Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
1183 Cards in this Set
- Front
- Back
|
3 Branches off Aortic Arch |
1. Innominate/brachiocephalic artery 2. Left CCA 3. Left Subclavian
|
|
|
What does innominate divide into |
Right CCA Right Subclavian
|
|
|
Location of subclavian arteries |
Posterior to clavicle & scalenus muscle |
|
|
At 1st rib, subclavian artery becomes what |
axillary artery |
|
|
Location & borders of axillary artery |
Runs to lower border of axilla Bordered in front by pectoral muscle, anterior thoracic nerve, arcromio-thoracic & cephalic veins |
|
|
Axillary artery becomes what |
Brachial artery |
|
|
Brachial artery bifurcates into |
Radial & Ulnar arteries |
|
|
Radial artery on which side |
thumb side/lateral aspect of forearm |
|
|
Ulnar Artery on which side |
pinky side/Inner side of forearm
Larger of two terminal branches of brachial artery |
|
|
Palmar arch |
Formed by ulnar artery in hand Completed by anastomosing w/ branch of radialis indicis |
|
|
Palmar arch courses where |
Over palm in curve to space between index finger & thumb |
|
|
What do the four digital branches supply |
Course between the fingers, superficial to flexor tendons
Provide blood supply to the fingers |
|
|
Location of CCA |
Lateral to trachea & thyroid gland
Courses up lateral aspect of neck to superior aspect of thyroid |
|
|
ICA provides blood to |
Anterior portion of brain, eye, & its appendages w/ branches to forehead & nose |
|
|
ICA location (in reference to ECA) |
Posterior to ECA |
|
|
4 segments of ICA |
Cervical portion Petrous portion Cavernous portion Cerebral portion |
|
|
ICA: Cervical portion |
Begins at bifurcation, opposite upper border of thyroid
Courses in front of cervical transverse processes to carotid canal
No branches typically seen |
|
|
ICA: Petrous portion |
Where the vessel enters the carotid canal |
|
|
ICA: Cavernous portion |
Where ICA is located between layers of dura matter forming cavernous sinus |
|
|
ICA: Cerebral portion |
Part of ICA passing between 2nd & 3rd cranial nerves at inner extremity of sylvian fissure where it gives rise to its terminal branches |
|
|
1st major branch of ICA |
Ophthalmic artery |
|
|
Ophthalmic artery: location & branches |
Enters orbit through optic foramen
Divides into its terminal branches: frontal, nasal, & supraorbital arteries |
|
|
Which cerebral arteries arise from ICA & serve as terminal branches of ICA |
Anterior cerebral Middle cerebral |
|
|
What connects the Anterior Cerebral Artery (ACA) with the opposite ACA? |
Anterior Communicating Artery |
|
|
ECA provides blood to |
Face & Scalp
(doesn't normally supply brain but can become collateral pathway if occlusion in ICA or vertebral) |
|
|
Location of ECA |
Commences at upper border of thyroid cartilage |
|
|
8 Branches of ECA |
Superior thyroid
(Some Aggressive Lovers Find Odd Positions More Stimulating) |
|
|
Superior Thyroid Artery |
1st branch of ECA |
|
|
Ascending Pharyngeal Artery: Location & Supply |
Smallest branch of ECA
Arises at level of carotid artery bifurcation
4 branches supply blood to longus coli muscle, lymph glands, palate, typani, & dura matter |
|
|
Lingual Artery: Location & Supplies |
Anterior branch arising between superior thyroid & facial arteries
Provides blood to tongue |
|
|
Facial Artery: Location & Supplies |
Arises just above lingual artery & courses along lower mandible, across cheek to the angle of the mouth, continues superior along side of nose to inner canthus of eye (becomes angular artery)
Provides blood to tongue, lips, nose, and lachrimal sac |
|
|
Occipital Artery: Location & Communication |
Arises from posterior portion of ECA opposite facial artery
Communicates w/ muscular branches of vertebral artery |
|
|
Posterior Auricular Artery: Location & Supplies |
Originates above digastric & stylo-hyoid muscles opposite apex of styloid process
3 branches
Supplies membranous tympani, back of ear, & muscle |
|
|
(Internal) Maxillary Artery: Location & Segments |
Large of two terminal branches of ECA
Arises at level of parotid gland opposite neck of condyle of lower jaw
Divides into 3 segments: maxillary pterygoid spheno-maxillary |
|
|
Superficial Temporarl Artery: Location & Supplies |
Smaller of 2 terminal branches of ECA Arises between neck & lower jaw & external auditory meatus
Divides into anterior temporal & posterior temporal
Provides blood supply to muscles & supraorbital rim |
|
|
Vertebral Arteries: Location/Path |
Arise from 1st segment of subclavian artery
Enter the transverse cervical foramina coursing up posterior aspect of neck
Then pass through atlas, winding around & passing beneath posterior occipital-atlantal ligament
Pierce the dura matter & arachnoid, entering skull through foramen magnum
|
|
|
Where do both vertebrals join & what do they form |
Join at midline at lower border of Pons Varoli to form basilar artery |
|
|
Vertebral Artery: Supplies |
Provide blood supply to posterior aspect of brain
Branches supply medulla & interior surface of cerebellum |
|
|
Circle of Willis - formed by |
In front - Anterior Cerebral Arteries (ACA)
In back - two Posterior Cerebral Arteries |
|
|
What connects the ACA branches of the ICA? |
Anterior Communicating Artery |
|
|
What connects the branches of the Basilar artery to the Middle Cerebral Arteries? |
Posterior Communicating Artery |
|
|
3 trunks that arise from Circle of Willis |
2 Anterior Cerebral Arteries Middle Cerebral Arteries Posterior Cerebral Arteries |
|
|
What do the trunks of the Circle of Willis supply? |
Each cerebral hemispher |
|
|
Most Common Malformation of Circle of Willis |
Absence/hypoplasia of one or more of the communicating arteries |
|
|
Where does the vessels of central ganglionic system arise? |
The Circle of Willis or vessels immediately after their origin from the Circle of Willis |
|
|
Cortical Arterial System: formed by & give rise to |
Formed by vessels which are terminal branches of anterior, middle, & posterior cerebral arteries
Give rise to nutrient arteries that penetrate cortex |
|
|
2 types of arterial branches that supply brain |
Penetrating Arteries
Superficial/Circumferential arteries |
|
|
Penetrating Arteries: supply |
Provide nutrient supply to CNS to support neuronal function |
|
|
Superficial/Circumferential Arteries |
Major arterial trunks that spread over entire surface of cervical hemispheres, brain stem, & spinal cord |
|
|
3 Categories of Intracranial Collateral Circulation |
Large interarterial connections
Intra-cranial extracranial pathway
Small interarterial communications |
|
|
Example of Large Interartial Connections |
Circle of Willis
Major collateral pathway that provides communication between two common carotid arteries or between basilar artery & right/left CCA |
|
|
Intra-cranial extracranial pathway |
Formed by anastomosis between ECA & ICA via orbital & ophthalmic & other ECA/ICA connections |
|
|
What are the most important ECA branches? |
Those which communicate with branches of ophthalmic artery
|
|
|
Examples of Important ECA Branches |
Include: facial with nasal superficial temporal to supraorbital internal maxillary to ophthalmic occipital with vertebral ascending pharyngeal to vertebral artery
Other connections: occipital artery w atlantic branch of vert
deep cervical & ascending cervical branches of subclavian w/ vert
|
|
|
Another name for Intracranial-extracranial connections |
Pre-Willisian anastomosis |
|
|
Small Interarterial Communications |
transdural anastomosis crossing subdural space from dural arteries on surface of brain |
|
|
Another name for Small Interarterial Communications |
Rete Mirable / wonderful net |
|
|
No effective anastomosis between? |
Neighboring cerebral arterial branches Deep penetrating arteries Superficial & deep cerebral arteries |
|
|
Risk Factors that contribute to development of atherosclerosis & subsequent stroke |
HTN Diabeters Smoking |
|
|
Reasons for non-invasive evaluation of CVS |
Asymptomatic bruits HX of TIA, Stroke Non-localizing symptoms Pts undergoing major cardiac or vascular procedure Obesity Family Hx of vascular disease Hyperlipidemia Stress |
|
|
Number 1 risk factor of stroke |
High blood pressure |
|
|
Theory of HTN = Stroke |
Accelerated flow rates seen with high blood pressure will increase the rate of damage to vessel wall at carotid bifurcation where there is already some degree of continual wear & tear due to turbulence
If stenosis exists, HTN can cause plaque components to become dislodged resulting in embolic event |
|
|
Mechanisms for extracranial disease |
Stenosis Thrombosis Embolism Cardiac Disease |
|
|
Stenosis (Definition) |
Narrowing of vessel lumen usually due to atherosclerotic plaque |
|
|
Embolic even result of? |
Can occur due to plaque ulceration & fibrinoplatelet material breaking off to embolize distally |
|
|
Thrombus formation |
Occurs with stagnation of blood flow
Components can embolize distally or totally occlude vessel |
|
|
Cardiac Sources of Embolic Event |
A Fib LV Dysfx Bacterial Endocarditis Prosthetic heart valve |
|
|
Atherosclerosis |
Progressive disease where fat deposits, calcifications, & fibers develop in intima & medial of arterial wall |
|
|
Atherosclerosis: permanent form |
Begins as fibrous plaque Uniform w/ smooth walls Progression leads to areas of necrosis & surface irregularities |
|
|
Plaque Ulceration |
Source of embolic event or thrombus formation |
|
|
Intraplaque hemorrhage |
Bleeding into plaque
Very unstable & may rupture sending shower of emboli that travel distally/cause rapid occlusion of vessel |
|
|
Arterial Dissection (Definition) |
Occurs when blood flows through a tear in media causing separation of intima & sometimes media creating new/false lumen |
|
|
Most common cause of dissection |
Weakening of arterial media associated w/ aging process |
|
|
Other Causes of Dissection |
Marfan's syndrome Fibromuscular dysplasia Chiropractic manipulation Blunt trauma Idiopathic |
|
|
Pt's Symptoms of Dissection |
Headache Neck/face pain Hemispheric symtpoms Cranial nerve palsy |
|
|
Dissection Classifications: DeBakey Model Type 1 |
Dissection begins at root extending entire length of arch & into abdomen |
|
|
Dissection Classifications: DeBakey Model Type 1 & 2 |
Considered to be most dangerous especially if it extends to CCA & Subclavian artery |
|
|
Dissection Classifications: DeBakey Model Subclavian Level |
Extend to descending aorta, but may/not continue into abdomen |
|
|
Dissection Classifications: DeBakey Model Type 3 |
Begins at lower descending Aorta & extends into abdomen
May be critical if it involves renal arteries |
|
|
Aortic Dissection of US |
2 lumens w/ echogenic intimal flap
Doppler/color evaluation may be helpful in documenting higher resistant flow in false lumen |
|
|
Subclavian Steal |
Occurs when there is flow-reducing lesion in subclavian or innominate artery PROXIMAL to origin of vertebral artery |
|
|
What does reduced flow in arm result in? |
Branchial pressure drop on affected side |
|
|
What happens to flow on side w/ pressure drop & why? |
Flow is reversed in vertebral artery on side w/ pressure drop to serve as collateral vessel to supply arm |
|
|
What does reverse flow in vertebral indicate? |
Subclavian steal |
|
|
What does a waveform alternating between forward & reverse indicate? |
Intermediate stage where subclavian artery stenosis is not causing sufficient pressure gradient to produce continuous reversal of flow |
|
|
Which side and in who is subclavian steal most common? |
Left side
Men |
|
|
Symptoms of subclavian steal |
Arm claudication due to lack of blood supply to muscle during exercise &/or may experience vertigo since blood supply is stolen from posterior circulation
Most pts asymptomatic |
|
|
Carotid Body Tumor: Location |
Located in adventitia of carotid bifurcation
Measures approx. 1 - 1.5 mm in size
|
|
|
Carotid Body Tumor |
Rare highly vascular tumors
Symptoms of palpable neck mass, headache, & beck pain
Usually benign & exhibit relentless growth |
|
|
Carotid Body Tumor: US appearance |
Mass will be seen separating ICA & ECA
Color/Spectral Doppler will revel high degree of vascularity
Sometimes mass may totally surround ECA or ICA |
|
|
Carotid Body Tumor: Treatment |
Surgical resection to prevent other associated complications such as invasion of carotid artery or laryngeal nerve palsy |
|
|
Fibromuscular Dysplasia (FMD) |
Non-inflammatory disease of arteries of unknown etiology |
|
|
FMD: Typically identified where? most common in who & where? |
Mid to distal segments of vessel
Most frequent in women
Most common in renal arteries (85%)
|
|
|
FMD: Most common location |
Renal arteries |
|
|
FMD: Second most common location |
ICA |
|
|
FMD: Symptoms & Reason for Referral |
Symptoms like TIA/Thromboembolic stroke
Most common referral for eval of asymptomatic cervical bruit |
|
|
FMD: 4 Types Based on Layers of Vessel Involved |
Intimal Fibroplasia Medial Fibroplasia Perimedial Fibroplasia Periarterial Fibroplasia |
|
|
FMD: US & Angiographic Appearance |
String of beads alternating dilation & narrowing of vessel |
|
|
Medial Fibroplasia Appearance |
Beading larger than proximal vessel caliber |
|
|
Perimedial Fibroplasia Appearance |
Beading smaller than proximal vessel caliber |
|
|
FMD: Treatment |
Varies from observation to surgical intervention |
|
|
Neointimal Hyperplasia |
Due to overgrowth of endothelial cells on intimal surface after surgery |
|
|
Most common cause of restenosis |
Smooth muscle & fibrous overgrowth |
|
|
Neointimal hyperplasia: US Appearance |
Diffuse narrowing at surgical site & increased velocity associated w/ post stenotic turbulence |
|
|
Follow up for Pts undergoing uncomplicated carotid endartectomy |
duplex/color follow up at 1-2 year intervals |
|
|
Amaurosis fugax |
transient loss of vision in one eye
"shade being pulled down over eye, either from top down or bottom up" |
|
|
Cause of Amaurosis fugax |
Embolic central retinal artery occlusion or Hollenhorst plaque |
|
|
Hollenhorst plaque |
Retinal cholesterol emboli |
|
|
Which side is disease when amaurosis fugax occurs? |
Same side as symptoms bc ophthalmic artery 1st major branch of ICA |
|
|
Vertebrobasilar Symtpoms |
Ataxia Limb weakness Drop attacks Visual disturbances Vertigo Dysarthria Headaches Vomiting |
|
|
How are symptoms categorized |
Depending on duration & effect on residual functions |
|
|
Transient Ischemic Attack |
Symptoms which last less than 24 hours
Usual duration is about 5 to 15 min
No residual effect |
|
|
Crescendo TIAs |
Monocular/hemispheric symptoms
Resolves within minutes after each attack w/ increase in frequency occurring several times per day
|
|
|
Percentage of pts with TIAs who have stroke w/in 3 months |
10% |
|
|
Pts w/ symptoms lasting at least 1 hour have what chance of stroke |
97% |
|
|
Reversible Ischemic Neurological Deficit (RIND) |
Symptoms last longer than 24 hours
Resolve w/in 72 hours |
|
|
Cerebrovascular Accident (CVA)/ Completed Stroke |
Symptoms last longer than 72 hours
Some degree of permanent residual deficit |
|
|
Other indications for non-invasively evaluating pts for CVA |
Carotid bruit High cardiovascular risk pt Pre Op eval for stenosis Other imaging tests suspicious for carotid disease |
|
|
Duplex Imaging |
Combination of high-resolution real time image & pulsed techniques |
|
|
Duplex Imaging: Provides |
Anatomical info regarding: location & course of vessel plaque formation visual placement of Doppler sample gate |
|
|
Color Imaging: Provides Info About |
Quality of flow Presence of flow Flow direction |
|
|
Spectral Doppler Interrogation Used To |
Quantify flow using measurements: Peak Systolic Velocity (PSV) End Diastolic Velocity (EDV) Velocirt Ratios |
|
|
Spectral Doppler evaluates: |
Flow quality & physiology |
|
|
Area Measurement: Technique |
Made by tracing true lumen of vessel followed by tracing of residual lumen |
|
|
Area Measurement Formula |
(True Lumen - Residual Lumen)/ (True Lumen x 100) |
|
|
Diameter Measurement Technique |
Anterior true wall to posterior true wall at site of max stenosis
|
|
|
Residual Lumen Measured |
Inside wall of plaque to bottom wall of plaque on opposite side of vessel |
|
|
50% diameter reduction = what CSA reduction |
75% |
|
|
Transducer Positioning: Anterior |
Pt looking up at ceiling, transducer on anterior of neck
Limited by angle of jaw & reduces ability to see bifurcation |
|
|
Transducer Positioning: Lateral |
Pt's head turned away, transducer on sternocleidomastoid muscle and aimed medially
Optimal view for most pts |
|
|
Transducer Positioning: Posterior |
Transducer behind sternocleidomastoid muscle and aimed anteriorly
Helpful for short neck or high bifurcation
**Posterior wall of ICA is seen first** |
|
|
Primary advantage of PW |
Range Resolution |
|
|
Primary disadvantage of PW |
Limitation in detecting high velocity flow at greater depth |
|
|
Aliasing Formula |
reflected freq > 1/2 PRF |
|
|
Eliminate Aliasing by: |
Adjusting zero baseline Increasing PRF (Scale, Velocity Range) Use CW |
|
|
Fast Fourier Techniques |
Computer method very rapidly analyzes full range of freq shifts & displays them on monitor in grayscale
Horizontal axis = time Vertical axis = freq &/or velocity Z axis = distribution of grayscale |
|
|
CCA: Waveform Characteristics |
Sharp systolic upstroke
Fairly rapid deceleration into diastole w/ prominent DICROTIC NOTCH
Diastolic flow above zero baseline
Compare to opposite CCA |
|
|
What differences between CCAs would represent significant proximal/distal disease? |
Significant changes in pulsatility & resistance |
|
|
ECA: Waveform Characteristics |
Sharp systolic upstroke
Rapid deceleration w/ prominent DICROTIC NOTCH
Diastolic flow diminished, absent, or reversed in nml vessel
|
|
|
ECA: Audible Signal |
Short & snappy w/ high pitch in systole
Little/no flow signal in diastole |
|
|
ICA: Waveform characteristics |
Sharp rise to systole w/ gradual deceleration into diastole
No dictoric notch
Diastolic flow above baseline |
|
|
ICA: Audible Signal |
Higher pitch systolic flow
Lower pitch signal in diastole |
|
|
Vertebral Artery: Waveform Characteristics |
Low resistance
Sharp rise to systole
Diastolic flow above baseline |
|
|
Subclavian Artery: Waveform Characteristics |
High resistance
Triphasic/multiphasic waveform
Sharp rise to systole
Rapid deceleration w/ reverse flow component followed by second forward component (triphasic) |
|
|
Color Assignment |
Normally - BART
Cerebrovascular & peripheral vascular - invert colors to show arteries red, veins blue
Abdominal & transcranial - standard BART |
|
|
Color Hues |
Changes in frequency shift
Higher reflected freq shift, lighter color displayed
|
|
|
Reasons for increase in freq shift |
Stenosis Changes in Doppler angle Vessel tortuosity |
|
|
What does black color hue represent |
crossing of baseline in spectral Doppler display |
|
|
Flow Separation/ Boundary separation layer |
The black layer separating the dark red and dark blue colors from reversal of flow
Normal in bulb, means free of significant disease |
|
|
Color Turbulence: distal to stenosis |
Mosaic pattern displayed as mixture of red, blue, and green colors
More severe stenosis, more severe post-stenotic color turbulence |
|
|
Color Aliasing |
Lighter shades of red & blue separated by white or green |
|
|
Optimization of technical factors for Color Doppler |
High velocity arterial - higher PRF, higher wall filter
Lower velocity venous/trickle arterial flow - lower PRF, lower wall filter
Change color box angle
Manipulate transducer to create angle to vessel |
|
|
General Color Optimization Factors |
Size of the color box to cover area of interest
Adjust color gain to fill vessel from wall to wall w/o splashing outside
|
|
|
Characteristics of Color Flow for CCA, ICA, Vertebrals |
Persistent flow throughout systole & diastole
Systole - lighter hues
Diastole - darker hues |
|
|
Characteristics of Color Flow for ECA |
color flow in systole
black or blue in diastole |
|
|
Power Doppler |
Analyzes strength or intensity of Doppler signal |
|
|
Power Doppler: More Sensitive in? |
Detecting presence of blood flow & not angle dependent |
|
|
Power Doppler: Advantages |
Allows more flexibility when interrogating low velocity flow, small vessels, and tissue perfusion
no aliasing
advantages for contrast since no splash outside vessel |
|
|
Power Doppler: Increased Sensitivity Achieved How |
Extensive use of dynamic range of dippler signal |
|
|
Power Doppler: Disadvantages |
Slower frame rate
Inability to derive quantitative info |
|
|
Stenosis Assessment: Factors that affect accuracy of study |
Knowledge & experience of technologist & physician
Capabilities of US equipment
Patient cooperation
Patient size & body habitus |
|
|
Evaluation of carotid artery stenosis includes |
Plaque characterization
Qualitative analysis of Doppler waveform profiles
Quantitative analysis of measurements
All taken at each site of interrogation |
|
|
Plaque Characterization on US |
Extent & severity
Evaluation of internal plaque composition
Surface characteristics
Assess plaque thickness - in Long for extent & in trv for thickness
|
|
|
Early US signs of Atherosclerosis |
Increased thickness of intimal & media layers |
|
|
Where Intima-medial thickness measurement is performed |
Obtained at distal CCA or prox ICA in long axis
Doesn't include visible plaque |
|
|
What IMT thickness is abnormal |
> .90 |
|
|
Plaque echogenicity: Fibrofatty plaques |
Low echogenicity due to high levels of lipid |
|
|
Plaque echogenicity: Fibrous plaques |
Medium level echogenicity due to increased amounts of collagen |
|
|
Plaque echogenicity: Calcific plaques |
Higher echogenicity with posterior acoustic shadowing |
|
|
Internal Composition of Plaque: Homogeneous plaque |
Uniform echogenicity w/o evidence of any focal areas of decreased echogenicity
Smooth surface
Scattered or focal calcifications may be seen |
|
|
Internal Composition of Plaque: Heterogeneous Plaque |
Complex in echogenicity
Exhibit at least one focal anechoic area
Sonolucent area may present intraplaque hemorrhage or lipid deposits
Surface may be smooth or irregular |
|
|
Doppler Characteristics: Qualitative Assessment |
Waveform Characteristics
Flow Direction Quality of flow |
|
|
Which arteries (in carotid study) show low resistance waveforms? |
CCA ICA Vertebral Artery |
|
|
Which arteries (in carotid study) show high resistance waveforms? |
ECA Subclavian Artery |
|
|
Laminar Flow (Description) |
Spectal flow profile w/ narrow range of freq
Area underneath systolic peak should be black |
|
|
Turbulent Flow (Description) |
Seen just distal to moderate/severe stenosis
Area underneath systolic peak filled in
Severe turbulence - flow below zero baseline
Color flow - mosaic pattern distal to stenosis |
|
|
Turbulent Flow: Mild to Moderate Window Filling Due To? |
Vessel Tortuosity
|
|
|
3 Quantitative Analysis of Velocities |
Peak Systolic Velocity
End Diastolic Velocity
Systolic Velocity Ratio |
|
|
Peak Systolic Velocity |
Most important
Increases w/ increased severity of stenosis
Obtained by placing cursor at max systolic peak of waveform |
|
|
What causes PSV to descrease rapidly in the setting of ICA stenosis >70%? |
Increased flow resistance |
|
|
End Diastolic Velocity |
Obtained by placing cursor on spectral tracing at end diastole just before onset of next systolic upstroke |
|
|
When & What are Elevated EDV? |
> 40 cm/sec in stenosis > 50% diameter reduction
> 100 cm/sec in stenosis >70% diameter reduction |
|
|
Systolic Velocity Ratio: Formula/Derived By |
PSV of ICA at max site of stenois ---------------------------------------------- PSV of CCA 1-4 cm prox to bifurc |
|
|
Where & What Doppler Interrogations Performed for Stenosis |
Prox to site of stenosis to evaluate flow characteristics
Throughout stenotic region to evaluate severity of disease
Distal to stenosis toe val post-stenotic turbulence |
|
|
Correlation Parameters (5) |
Presence & Severity of Plaque Formation
Plaque Characteristics
Spectral Doppler Quantitative Analysis
Waveform Morphology
Qualitative Flow Analysis |
|
|
When Distal Disease Present, Flow changes seen where? |
Proximal vessel segments
Ex. Diastolic flow in CCA will decrease as severity of ICA stenosis increases > 70%
Compared to contralateral side, discrepancy in diastolic flow noted |
|
|
Rule of Thumb (4 D's) |
Decreased Diastolic Flow = Distal Disease |
|
|
Total Vessel Occlusion: Characterized by |
Lack of arterial pulsations
Debris-filled vessel
Decreased diastolic CCA flow
No flow signal in the affected vessel
Small vessel size in chronic occlusion |
|
|
System Controls to Adjust to R/O Low Flow State |
Lowering PRF (min 2000 Hz)
Decrease wall filter settings (min 25 Hz)
Increase sample gate size & doppler/color gain
Power Doppler
Increase Doppler/color gain |
|
|
Severe Proximal Disease Exhibits What |
Changes in Systolic Flow Characteristics |
|
|
Tardus & Parvus Waveform |
Demonstrates delayed systolic acceleration time
Peak systolic velocity severely reduced & can reach 1:1 ratio w/ diastolic flow component
PSV affected along entire course of vessel & can result in underestimation of distal stenosis |
|
|
North American Symptomatic Carotid Endarterectomy Trial (NASCET) |
Endartectomy greater long-term benefits for symptomatic pts w/ > 70% stenosis (vs medicine)
Pts w/ 50-69% stenosis w/ ispilateral hemispheric TIA or CVA benefit from surgery
|
|
|
Asymptomatic Carotid Atherosclerosis Study (ACAS) |
Surgical benefit for asymptomatic pts w/ > 60% stenosis w/ good-risk for prophylactic surgery |
|
|
CEA |
Carotid Endarterectomy |
|
|
University of Washington Criteria: Stenosis 0-15% |
PSV < 125 cm/s Little/no spectral broadening |
|
|
University of Washington Criteria: Stenosis 16-49% |
PSV > 125 cm/s Spec broadening thru/o systole |
|
|
University of Washington Criteria: Stenosis 50-69% |
PSV > 125 cm/s Extensive spectral broadening |
|
|
University of Washington Criteria: Stenosis 70-99% |
PSV > 125 EDV > 140 Extensive spectral broadening |
|
|
University of Washington criteria based on ? |
Traditional angiographic correlation w/ measurements comparing diameter of residual lumen at max site of stenosis to diameter of ICA bulb if no plaque present |
|
|
NASCET criteria based on? |
Comparison of residual lumen at max site of stenosis to distal ICA lumen diameter |
|
|
SRU Consensus Criteria: Parameters Evaluated |
ICA PSV IVA EDV ICA/CCA PSV ratio ICA/CCA EDV ratio |
|
|
SRU Consensus Criteria: Normal |
ICA PSV < 125 cm/s ICA EDV < 40 ICA/CCA PSV ratio < 2 Plaque - none |
|
|
SRU Consensus Criteria: < 50% |
ICA PSV < 125 ICA EDV < 40 ICA/CCA PSV ratio < 2 Plaque - < 50% diam reduc |
|
|
SRU Consensus Criteria: 50-69% |
ICA PSV 125-230 ICA EDV 40-100 ICA/CCA PSV ratio 2-4 Plaque >/= 50% diam reduc |
|
|
SRU Consensus Criteria: > 70% |
ICA PSV > 230 ICA EDV > 100 ICA/CCA PSV ratio > 4 Plaque >/= 50% diam reduction |
|
|
SRU Consensus Criteria: Near occlusion |
ICA PSV - low or undetectable ICA EDV - variable ICA/CCA PSV ratio - variable Plaque - visible |
|
|
SRU Consensus Criteria: Total Occlusion |
ICA PSV - undetectable ICA EDV - N/A ICA/CCA PSV ratio N/A Plaque - visible; no detectable lumen |
|
|
Intraoperative US: performed for to assess what |
Adequacy of reconstructed lumen Detect intimal flaps or dissections Determine if signficicant restenosis present |
|
|
TCD Intraoperatively: |
Provides immediate info regarding cerebral perfusion
Helps assess amount of microembolization during dissection & wound closure to predict risk of post op stroke
M1 segment of MCA evaluated continuous/repeatedly during CEA or open-heart surgery (>10 cm/s = adequate collateral circulation) |
|
|
Intraoperative US to eval pt for: |
Portal HTN undergoing surgical portosystemic shunting
Renal trumors
Partial nephrectomy
Guide radioactive seed placement for postate brachytherapy & neurosurgical applications |
|
|
Intraoperative US visualizes: |
Vasculature Tumor borders Extent of tumor invasion |
|
|
Transcranial Doppler: Definition |
Non-invasive technique for evaluating blood flow info from intracranial arteries located at base of brain |
|
|
Clinical Applications of TCD |
Detecting severe stenosis in major intracranial vessels
Assessment of patterns & extent of collateral circulation w/ known regions of severe stenosis or occlusion
Detecting of arteriovenous malformations (AVM) & supplying arteries
Evaluation & F/U w/ vasospasm after subarachnoid hemorrhage
Assessment of pts w/ suspicion of brain death
Screening for stenosis in pediatric pts w/ sickle cell |
|
|
Indications of TCD |
Pt symptomatic for cerebrovascular disease
Pt w/ known cerebrovascular disease > 8-% diameter reduction
Pt w/ normal carotid duplex exam w/ peristent TIAs
Pt w/ subarachnoid hemorrhage who are at risk for vasospasm
Pt w/ head trauma who may need eval for hyperdynamic flow |
|
|
Cerebrovascular Anatomy evaluated by TCD |
Anterior Circulation Posterior Circulation Siphon Genu |
|
|
A. Anterior Communicating Artery B. Anterior Cerebral Artery C. Middle Cerebral Artery D. Posterior Cerebral Artery E. Basilar Artery F. Vertebral Artery G. Posterior Communicating Artery H. Internal Carotid Artery |
|
|
TCD: Temporal Window - Evaluates Flow in ? |
MCA ACA PCA Terminal ICA Anterior Communicating Artery Posterior Communicating Artery |
|
|
TCD: Temporal Window - Transducer Placement |
Front of ear, over temporal bone just superior to zygomatic arch |
|
|
TCD: Temporal Window - Depth |
55 to 65 mm |
|
|
TCD - MCA |
First segment M1 - direct continuation of ICA
Bifurcates into M2
Courses superiorly & posteriorly into deepest portion of Sylvian fissure |
|
|
MCA supplies? |
Lateral surfaces of both hemispheres |
|
|
MCA: Depth, Flow Direction, Mean Velocity |
Depth - 30 - 65 mm
Flow Direction - towards transducer, low resistance
Nml mean velocity - 55 cm/s +/- 12 |
|
|
ACA/MCA birfucation: Flow & Locating ACA |
Bidirectional flow
Locate ACA by angling sound beam anterior from MCA |
|
|
ACA: Depth, Flow Direction, Mean Velocity |
Depth - 60 to 88 mm
Flow Direction - away from transducer, low resistance
Nml mean velocity - 50 cm/s +/- 11 |
|
|
Posterior Cerebral Arteries: Terminal branches of? |
Basilar Artery |
|
|
Posterior Cerebral Arteries: P1 Segment courses? |
Anterior & Lateral |
|
|
Posterior Cerebral Arteries: P2 Segment courses? |
Posterior & Superiorly |
|
|
Posterior Cerebral Arteries(PCA): Relation to MCA |
Sound beam angled posterior from level of MCA |
|
|
Posterior Cerebral Arteries (PCA): Depth, Flow Direction, Mean Velocity |
Depth - 60 to 70 mm
Flow Direction - P1 towards transducer; P2 away from transducer
Nml Mean Velocity - 39 cm/s +/- 9 |
|
|
Imaging Landmark for PCA |
Peduncles |
|
|
Terminal ICA: Located? |
Angle sound beam towards feet from level of posterior cerebral arteries or peduncle area |
|
|
Terminal ICA: Depth, Flow Direction, Mean Velocity |
Depth - 55 to 65 mm
Flow Direction - towards transducer
Nml Mean Velocity - 39 cm/s +/- 9 |
|
|
Terminal ICA - Imaging Landmarks |
Sphenoid & Petrous bones |
|
|
Posterior Communicating Artery: Located? |
Angle transducer posterior from level of bifurcation |
|
|
Posterior Communicating Artery: Depth, Flow Direction, Mean Velocity |
Depth - ~75 mm
Flow Direction - P1 towards transducer, P2 not always seen but would be away from transducer
Nml Mean Velocity - 39 cm/s +/- 9 |
|
|
Occipital Window: Evaluates? |
Vertebral & Basilar Arteries |
|
|
Occipital Window: Transducer Placement |
Base of skull at hairline level
Sometimes off center and angled towards side of interest |
|
|
Vertebral Arteries: Depth, Flow Direction, Mean Velocity |
Depth - 60 to 90 mm
Flow Direction - away from transducer
Nml Mean Velocity - 38 cm/s +/- 10 |
|
|
Basilar Artery: Depth, Flow Direction, Mean Velocity |
Depth - 80 to 120 mm
Flow Direction - away from transducer
Nml Mean Velocity - 41 cm/s +/- 9 |
|
|
Vertebral & Basilar Arteries: Imaging Landmark |
Foramen Magnum |
|
|
Orbital Window: Evaluates? |
Ophthalmic Artery
Carotid Siphon |
|
|
Orbital Window: Transducer Placement |
Over closed eyelid & power setting lowered
Only non-imaging pulsed doppler TCD should be used |
|
|
Ophthalmic Artery: Depth, Flow Direction, Mean Velocity |
Depth - 50 mm
Flow Direction - towards transducer
Nml Mean Velocity - 21 cm/s |
|
|
Carotid Siphon: Depth, Flow Direction, Mean Velocity |
Depth - 6 cm
Flow Direction - toward, away, bidirectional
Nml Mean Velocity - 41 cm/s +/- 11 |
|
|
Factors of Primary Interest for determining nml TCD |
All Vessels low resistance
Mean velocity: MCA ~ 79 cm/s MCA > ACA > PCA = BA = Vertebral
Depth of Vessel & Angulation aid in identifying vessels
Flow Direction Important (towards - MCA & PCA; Away - ACA, PCA, Vetebral, Basilar |
|
|
TCD Vessels Exhibiting Flow Away From Transducer |
ACA
PCA
Vertebral
Basilar |
|
|
TCD Vessels Exhibiting Flow Toward Transducer |
MCA
PCA |
|
|
MCA Stenosis: Determined by |
Identify localized increase in velocity combined w/ post-stenotic turbulence |
|
|
Flow Changes in Intracranial Vessel secondary to severe ICA stenosis or occlusion will reveal: |
Slow upstrokes to systole
Lower velocity on affected side
Decrease in pulsatility index |
|
|
Collateral Flow: ICA Obstruction fed from Contralateral Side on TCD will show |
Reverse flow in ipsilateral or receiving side anterior cerebral artery
Increased velocity in contralateral ACA > 150% of MCA on same side
Damped ipsilateral MCA flow |
|
|
ECA - ICA Collateral (via Ophthalmic Artery) Reveal |
Reverse flow in ophthalmic artery on side of obstruction
Ophthalmic artery pulsatility low
Decreased, absent or reverse flow w/ compression of superficial temporal artery & facial artery |
|
|
Vasospam: Occurs most frequently due to |
Cerebral Aneurysm Rupture
|
|
|
Vasospams: Other Reasons for Occurence |
Head Trauma
Intracerebral hematoma
Arteriovenous Malformation
Tumor Formation |
|
|
Cerebral Artery spasm following subarachnoid hemorrhage is major cause of? |
Mortality |
|
|
Evaluation for Vasospasm involves |
Monitoring of Flow Velocities
Day to day changes > 20 cm/s usually progress to severe spasm
Larger the bleed, higher the risk of spasm
Flow changes same as stenosis
Baseline study day zero, repeat study day four |
|
|
Treatment fro Vasospasm |
Early surgical intervention w/in 24-72 hrs to clip aneurysm
Aggressive vasospasm tx then implemented |
|
|
Arteriography: Used for |
Invasive procedure
Pre operative assessment of arterial anatomy & pathology after initial non-invasive test has been completed & indications for further eval are recommended |
|
|
Arteriography: Provides info about |
Arch vessels
Extracranial cerebrovascular vessels
Intracranial circulation
|
|
|
Arteriography: Provides Diagnosis of |
Subclavian Steal
Intimal Flaps
Pseudoaneurysms
A-V Fistula
Dissection
Arteritis |
|
|
Arteriography: Process |
Radioplaque material injected into artery & multiple x-ray films obtained
AP, Lateral, Oblique views to allow adequate visualization of anatomy & regions of abnormality |
|
|
Quality Arteriogram: Influenced by |
Selection of most appropriate contrast agent
Determining best radiographic projections
Selecting proper injection volume
Rate of injection volume along w/ synchronization of rapid filming |
|
|
Arteriography: Performed by |
Using catheter system w/ radiolucent plastic sheath w/ soft tip or Seldinger method which uses guide wire system |
|
|
Arteriography: 4 Basic Approaches for Accessing Arterial System |
Transfemoral
Transaxillary
Brachial
Translumbar
|
|
|
What determines which access point to use |
Distribution of disease
Primary region of interest |
|
|
Arteriography: Complications |
Due to administration of contrast media or mechanical vascular injury from manipulation of catheter |
|
|
Patients most at risk for complication of renal failure from arteriography |
Low renal blood flow
Diabetes
Proteinuria
Dehydration
Pre-existing renal insufficiency |
|
|
Pts w/ hx of MI at risk due to: |
Contrast agent is myocardial depressant resulting in hypotension |
|
|
Other side effects of contrast agents |
Convulsion
Cortical blindness
Frank stroke |
|
|
Mechanical Complications from catheter manipulation include: |
Bleeding (most common complication)
Thrombosis
A-V fistula
Pseudoaneurysm |
|
|
Interpretation of arterigram |
Identifying arteries/ segments of vessel that do not opacify |
|
|
Magnetic Resonance Angiography (MRA): Used to Detect |
Intracranial aneurysm
Intracranial vascular disease
Thrombosis of major cerebral veins
|
|
|
MRA: Technique |
Manipulates signal from blood to allow vessels to be separated from surround tissue |
|
|
2 Types of MR Techniques |
Time of Flight
Phase Contrast |
|
|
MR: Time of Flight Technique |
More commonly used
Less time consuming
High intesnity signals received from surrounding tissue to allow blood vessels w/ flowing blood to be highlighted |
|
|
MR: Phase Contrast |
Velocity differences & phase shifts from moving blood to provide image contrast
Used to determine speed & direction of blood flow |
|
|
MR: Limitations |
Patient's unable to remain still for at least 10 minutes render non-diagnostic tests since MR very sensitive to movement |
|
|
Computed Tomography Angiography (CTA) |
Combines use of x rays & computerized image anaylsis to evaluate blood flow in arterial vessels
Cross sectional images assembled by computer into 3D picture of region of interest |
|
|
CTA: Used for |
Detection of stenosis or occlusion of arteries
Evaluate stent placement |
|
|
CTA: Limitations |
Pt movement results in blurred images
Difficulty imaging totally occluded vessels as well as small tortuous vessels |
|
|
Treatment/Follow Up: Medical Therapy |
Pts w/ carotid disease < 70% |
|
|
Medical Therapy Includes |
Thrombin inhibitors
Platelet antiaggregants
Antihypertensive medications |
|
|
3 caterogies of Stroke Treatment |
Prevention
Acute
Subacute/chronic tx |
|
|
Stroke: Primary Prevention |
Initiated in pts w/ no previous hx of stroke
Involves platelet antiaggregants (Aspirin, Statins, & exercise) |
|
|
Stroke: Secondary Prevention |
Suggested in pts who have had stroke
Includes platelet aggregants, statins, antihypertensives, &/or thrombin inhibitors |
|
|
Stroke: Acute Treatment |
Must be initiated w/in 0-24 hrs from onset of stroke
Includes thrombolytics, anticoagulants, statins, antihypertensives, neuroprotectants |
|
|
Medical Therapy: Pts w/ A Fib |
Pts w/ a fib are at risk for stroke
Stagnation of slow blood flow procedures blood clots that can cause an embolic event |
|
|
Endovascular: Angioplasty on Symptomatic Pt |
Carotid disease > 70% diameter stenosis
Failed medical tx
Not good surgical canditates due to location of stenosis or health issues |
|
|
Complete Angiographic Evaluation: Performed to |
Document the location & degree of stenosis
Adequacy of collateral blood supply to affected territory
Associated pathology |
|
|
Angioplasty: Procedure Process |
Performed by inserting soft-tipped excahnge guidewire into stenosis & balloon angioplasty catheter w/ ability to inflate to diameter equal to lumen diameter of adjacent nml vessel & 1 to 2 cm longer than stenotic area
Balloon inflated 10 to 30 sec
Repeat inflation may be necessary if significant residual stenosis |
|
|
Angioplasty: Potential Complications |
Arterial Dissections
Spasm
Occlusion
Thromboembolism |
|
|
Stent Placement |
Reduces incidence of intimal flap when places simultaneously w/ dilation of stenosis
Reduces rate of subsequent thrombosis of vessel |
|
|
Advantages of Angioplasty |
Perform procedure under local anesthesia
Possibility of treating stenosis that is inaccessible or difficult to approach surgically
Elimination of other surgical risks s/a cranial nerve injury
Reduced pt discomfort
Potentially shorter hospital stay |
|
|
Endartectomy: Performed to |
Remove atherosclerotic plaque w/in artery
Prevent pt from having further possible catastrophic events
Not on pt who have total occlusion |
|
|
North America Symptomatic Carotid Endartectomy Trial (NASCET): Endarterectomy Benefits who |
Symptomatic pts
> 50 % diameter reduction |
|
|
National Institute of Neurological Disorders and Strokes: Asymptomatic Atherosclerosis Study (ACA): Endarterectomy Benefits Who |
Asymptomatic carotid stenosis > 60% diameter reduction confirmed by angiography in these situations: - Endartectomy performed in medical centers w/ documented combined preop morbidity & mortality for asymptomatic edartectomy of < 3% - Endartectomy performed on carefully selected pt who continue to have aggressive modifiable risk factor management |
|
|
Pulmonary circulation |
Circulation in lungs |
|
|
Carries deoxygenated blood to lungs |
Pulmonary arteries |
|
|
Carries oxygenated blood back to LA |
Pulmonary veins |
|
|
Systemic circulation |
General/peripheral circulation |
|
|
Portal Circulation |
Return of blood from viscera to liver, where it travels to IVC then onto RA |
|
|
Deep veins located where? |
Deep in tissue, below fascia & surrounded by muscle
Have direct communication w/ IVC & SVC |
|
|
Superficial Venous System located? |
Between layers of superficial fascia beneath integument
Return blood from these areas & communicate w/ deep veins via perforating/communicating veins |
|
|
Perforating veins: Connect what & reason for name |
Connect superficial to deep system
Perforate fascia when connecting 2 systems |
|
|
Deep Palmar Veins: Accompany what & Communicates w/ |
Accompanies deep palmar arch
Communicates w/ deep ulnar veins |
|
|
Deep Palmar Veins unite with what vessels at wrist |
Radial Veins |
|
|
Interosseous veins: Accompany what & connect with what at wrist |
Accompany anterior & posterior interosseous arteries
Connect w/ Radial & Ulnar Veins at wrist |
|
|
Common Ulnar Vein: Formed by & Joins what |
Short trunk formed by Anterior & Posterior Ulnar Veins
Joins median basilic vein to form basilic vein of superficial system |
|
|
Radial & Ulnar Veins: Join where & form what |
Join at elbow
Form brachial vein |
|
|
Why are Radial & Ulnar veins not always considered part of deep system? |
Vary in course above & below fascia |
|
|
Brachial Vein: Begins where, Courses where, & Ends Where |
Begins at antecubital fossa at elbow
Courses adjacent to Brachial Artery along entire humerus
Terminates to form Axillary Vein |
|
|
Axillary Vein: Location & # of Valves |
Located at level of armpit
~ 2 valves |
|
|
Subclavian Vein: Courses Where |
Continuation of Axillary Vein
Courses from outer border of 1st rib to inner end of clavicle
|
|
|
What vessel does Subclavian vein join & together they form what? |
Joins IJV to form Innominate Vein |
|
|
Right Innominate Vein: Begins where & Joins w/ Left Innominate where |
Begins at inner medial end of clavicle
Joins w/ Left Innominate Vein just below 1st rib to form SVC |
|
|
Right Innominate Vein receives blood from what vessels? |
Right Vertebral Vein
Right Internal Mammary
Right Inferior Thyroid
Right Superior Intercostal Veins (Sometimes) |
|
|
Which Innominate Vein is larger? |
Left |
|
|
Left Innominate Vein: Courses Where & Joins Right Innominate where? |
Courses from Left to right across upper anterior aspect of chest
Joins w/ Right Innominate Vein to form SVC |
|
|
SVC receives blood from what vessels? |
Right & Left Innominate Veins |
|
|
Where does SVC commence? terminate? |
Commences just below 1st rib on right side
Enters pericardium
Terminates at RA |
|
|
Inner & Outer Plexus Join to form what on back of hand? |
Superficial Arch |
|
|
Median Vein: Courses where & joins what vessels? |
Courses along inner aspect of forearm
Joins w/ anterior ulnar & radial veins |
|
|
What & Where does Median Vein divide? |
Divides at antecubital fossa
Divides into Cephalic & Basilic veins |
|
|
Median Cephalic Vevin: Courses where & joins what vessels |
Courses through groove btw supinator longus & biceps muscle
Joins w/ radial & cephalic veins |
|
|
What does Median Basilic Vein unite with & what does it form? |
Joins w/ Common Ulnar Vein to form Basilic Vein
|
|
|
Where does Median Basilic Vein course? |
In front of Brachial Artery |
|
|
Basilic Vein: Formed by & location |
Formed by Common Ulnar & Median Basilic Veins
Located on inner side of Bicpes muscle & at Axillary Vein |
|
|
What is the largest superficial vein? |
Basilic Vein |
|
|
Cephalic Vein: Courses where |
Courses along outer border of biceps muscle
|
|
|
Cephalic Vein Terminates Where |
Just below clavicle into Subclavian vein
Sometimes ends in Axillary Vein |
|
|
Common Iliac vein: Location |
Begin at approximately 4th lumbar vertebrae @ level of bifurcation of IVC |
|
|
Common Iliac Vein divides into? |
Internal Iliac & External Iliac Veins |
|
|
Does Internal Iliac Veins contain valves? |
No |
|
|
Left External Iliac Vein: Courses where |
Along inner side of corresponding artery |
|
|
Right External Iliac Vein: Courses where |
Along inner side of iliac artery & then continues in path behind artery |
|
|
Where does External Iliac Veins receive blood from? |
Deep epigastric & Circumflex veins |
|
|
How many valves are contained in External Iliac Veins? |
Up to 2 valves |
|
|
Common Femoral Vein (CFV): Location |
At level of inguinal ligament in crease of groin
Lies medial to CFA |
|
|
Sapheno-femoral Junction (SFJ) |
Located where GSV drains into CFV |
|
|
CFV: Divides into |
Femoral (formerly SFV) & Deep Femoral Vein (Profunda/DFV) |
|
|
Femoral Vein (FV): location |
Adjacent to SFA
Commences just below inguinal ligament
Extends down enitre length of thigh
Distally courses posteriorly through adductor canal to form Pop Vein |
|
|
Approximately how much of population has duplicate FVs? |
25% |
|
|
How many valves does FV contain? |
up to 4 valves |
|
|
Popliteal Vein: Receives blood from where |
Sural veins from gastrocnemius muscle
Articular Veins
Lesser Saphenous Veins (LSV) |
|
|
Approximately how much of population has duplicate Pop Veins? |
25% |
|
|
How many valves does the Pop Vein contain? |
~ 4 valves |
|
|
Anterior Tibial Veins: Formed by what & Courses where |
Dorsalis Pedis Veins form ATVs
Courses between tibia & fibula above interosseous membrane |
|
|
What is the ratio of veins to arterys in the calf? |
At least 2 veins to each artery in calf |
|
|
Tibial & Peroneal Veins: Valves |
About every 2 cm along length of vessel there is a valve |
|
|
Posterior Tibial Veins (PTVs): Formed by & Located where |
Formed by External & Internal Plantar Veins
Located posterior to medial malleolus, continuing along medial aspect of lower leg to form Tibio-peroneal trunk about 3 fingerbreadths below knee |
|
|
PTVs receive blood from where |
Soleal sinuses in calf muscle |
|
|
Peroneal Veins: Course where |
Along posterolateral trunk @ same level as PTVs |
|
|
What vessels make up LE Superficial Venous System? |
GSV
LSV |
|
|
Greaster/Long Saphenous Vein (GSV): Begins & Courses Where & Terminates Where |
Begins anterior to medial malleoulus
Courses along inner side of leg behind tibia
Terminates at CFV just below inguinal ligament |
|
|
GSV: Receives Blood from where |
Ankle Perforating Veins & numerous other tributary veins |
|
|
Approximately how many valves does the GSV contain? |
10 to 12 valves |
|
|
Lesser/Short Saphenous Vein (LSV): Begins Where & Courses Where & Terminates Where |
Begins at outer dorsum of foot
Courses behind lateral malleous
Terminates at Pop Vein |
|
|
Approximately how many valves does LSV contain? |
3 to 9 valves |
|
|
Direction of blood flow in perforating veins? |
From Superficial system to deep system |
|
|
4 main groups of Perforators (clinically relevant for treating GSV insufficiency) |
Hunterian Perforator
Cockett/Linton Perforators
Boyd's Perforating Vein
Dodd's Perforators |
|
|
Location of Hunterian Perforator |
Mid-Upper medial thigh |
|
|
Cockett/Linton Perforators: Connect what |
connect PTVs to Posterior Arch Vein at ankle region |
|
|
Boyd's Perforating Vein: Connect what |
Connect GSV to PTVs in upper calf |
|
|
Dodd's Perforators: Connect what |
GSV to FV in medial thigh above knee |
|
|
Giacomini Vein |
Extension of LSV beyond Pop V to become continguous w/ Profunda Femoris Vein (PFV) |
|
|
Alternate Path of Giacomini Vein |
Alternates superficially curving around leg to join GSV by its posteromedial branch in upper thigh |
|
|
IVC: Begins, Courses, Terminates |
Begins @ level of 4th lumbar vertebra
Courses adjacent to right side of AO
Terminates at RA |
|
|
IVC: Receives blood from |
LE
Renal veins
Hepatic veins |
|
|
What forms Portal Venous System |
Confluence of: Splenic Vein Inferior Mesenteric Vein Superior Mesenteric Vein |
|
|
Portal Vein: Location & Course |
Located anterior to IVC
Courses into liver & divides into right & left Portal Veins |
|
|
How much oxygenated blood does the Portal Vein carry? |
75% |
|
|
Portal Vein: Receives blood from |
Spleen
Pancreas
Stomach
Other abdominal viscera |
|
|
Hepatic Veins: Transport blood where |
From liver to IVC |
|
|
Left Renal Vein: Course & Terminates |
Courses anterior to AO & posterior to SMA
Terminates at IVC |
|
|
Right Renal Vein: Course & Terminates |
Courses directly from kidney into IVC |
|
|
Renal Veins course ______ to Renal Artery (Anterior, Posterior, Inferior, Superior) |
Anterior |
|
|
Venous Capillaries: Composition |
Single layer of endothelial wall that allows absorption of gases & chemicals into blood
Blood flows from capillary bed to venules |
|
|
Venules: 2 layers |
Outer adventitia
Endothelium |
|
|
Venule: Adventitia - Composition & Purpose |
Thinnger & less strong as compared to arteries
Allows veins to expand w/ changes in position or gravity |
|
|
Name of internal vessels that feed the walls of arteries & veins |
Vasa Vasoorum |
|
|
4 Main Functions of Veins |
Regulate body temperature
Control rate of blood return to heart & regulate cardiac output
Store 2/3 to 3/4 of body's total blood volume
Act as highway to transport blood out of organ or extremity towards heart |
|
|
What does the location of veins help with & How? |
Helps regulate temprature
Superficial veins great for cooling
Deep veins w/in muscles warm blood |
|
|
What is the ability of veins to expand and collapse w/o change in pressure helpful in? |
Thermal control |
|
|
3 Primary contributing factors to blood flow in UE & LE |
Heart contraction
Intraluminal blood pressure
Peripheral resistance in capillary beds |
|
|
What is required for blood to flow? |
Pressure gradient |
|
|
Blood flows towards which type of pressure ? (high or low) |
Blood flows from high pressure to low pressure |
|
|
Contributing factors to energy loss: |
Viscosity
Blood volume
Vessel length
Vessel diameter |
|
|
In a prone pt what is the intraluminal venous pressure gradient? What does it decrease to at level of RA? |
15 mmHg
0 at level of RA |
|
|
Where is the highest pressure? |
In the arterioles |
|
|
Where is the lowest pressure? |
Venules |
|
|
Intravascular pressure |
Sum of static filling pressure, dynamic pressure from LV contraction, & hydrostatic pressure |
|
|
Which is not important in venous pressure system? Dynamic or Hydrostatic |
Dynamic pressure from LV contraction not imporant |
|
|
Hydrostatic pressure calculated as |
Product of specific gravity of blood, gravitational acceleration, & vertical distance from heart |
|
|
The ______ the vertical distance from the heart, the _________ the outward force against the vein walls. |
Further; greater |
|
|
Where is the greatest vertical distance achieved? |
Ankles of a standing patient
Produces greatest hydrostatic pressure |
|
|
Is the value of hydrostatic pressure positive or negative in a raised arm above the heart? |
Negative value above the heart |
|
|
Is the value of hydrostatic pressure positive or negative below the heart? |
Positive value below the heart |
|
|
In a supine pt, the vertical distance from the heart is? |
Negligible |
|
|
Where does edema occur? |
Edema occurs where intravascular pressure exceeds tissue pressure |
|
|
How is venous blood returned to the heart? |
Contraction of calf muscle (veno-motor pump) |
|
|
What does the effectiveness of the pump depend on? |
Forcefulness of venous contraction
Competence of venous valves |
|
|
How does calf muscle pump work? |
It shunts blood out of deep muscular sinuses into deep veins of thigh, onward & upward into heart
As blood is moved out of calf veins, intramural & transmural pressure drops. This decreases amount of fluid shunted into tissue surrounding capillaries |
|
|
What happens if the muscle contraction is weak? |
Less blood is moved out of leg & transmural pressure will remain high |
|
|
What happens with incompetent valves? |
Blood is pushed out with muscle contraction but falls back into the leg with relaxation (reflux)
Arteries will bring blood into the leg faster than veins can carry it out |
|
|
Efficient muscle pump shows what |
No/low flow at rest
Augmented forward flow w/ contraction
No/low flor on relaxation |
|
|
Inefficient muscle pump (due to venous incompetence) shows what |
Reflux at rest
Augmented flow on contraction
Reflux on relaxation
Blood goes up & then falls back down |
|
|
Transmural pressure: Definition |
Difference/gradient between intramural & tissue pressure |
|
|
What does increased trasmural pressure create? |
Distended vein |
|
|
What happens when tissue pressure exceeds intramural pressure? |
Vein collapses |
|
|
What happens on inspiration to the IVC? |
Diaphragm descends causing increase in abdominal pressure of tissue pressure around IVC
Transmural pressure drops & IVC collapses
|
|
|
What happens on inspiration to the CFV? |
CFV experiences increased resistance to flow
Intramural pressure rises, as does transmural pressure, forcing vein to expand
|
|
|
What happens on inspiration to the Calf Veins? |
Assuming venous valves competent distal to CFV, veins of calf should experience no change in pressure or volume |
|
|
What happens on expiration? |
Transmural pressure is higher & velocity profile accelerates slight back toward heart |
|
|
What can impede flow into the heart? |
Anything that causes increased RA pressure or central venous pressure |
|
|
What are some examples of things that can impede flow? |
Tricuspid Regurg Tricuspid Stenosis CHF |
|
|
How many cases of acute DVT are reported each year? |
2.5 million cases |
|
|
How many people will develop a pulmonary embolus? How many will die? |
650,000; 150,000 |
|
|
What helps significantly decrease incidence of pulmonary embolus & post-phlebitic syndrome? |
Early detection & treatment of acute DVTs |
|
|
Virchow's Triad |
Stasis
Wall Injury (intimal)
Hypercoagulability |
|
|
Specific Risk Factors that increase risk of acute DVT |
Prior Hx of DVT
Trauma
Obesity
Blood Clotting Disorder
Cancer
Recent surgery
Prolonged inactivity
Use of oral contraceptives
Increased central venous pressure (CHF, TR)
Pregnancy |
|
|
Classic Presentation of LE Acute DVT |
Leg swelling
Edema
Dilated superficial veins along calf & thigh tenderness |
|
|
How does the leg feel for an acute DVT? |
Warm & tender |
|
|
How often does bilateral acute DVTs occur? |
< 1 % |
|
|
Other clinical signs of acute DVT |
Positive Neuhof's sign
Positive Homan's sign
Palpable, painful popliteal cord |
|
|
What is a Positive Neuhof sign |
Pain upon palpation of PTVs about 6-7" above Achilles tendon |
|
|
What is a positive Homan sign |
Pain upon dorsiflexion of foot
Test is insensitive & nonspecific |
|
|
Phlegmasia Alba Dolens |
Condition where there is severe ilio-femoral venous thrombosis |
|
|
Phlegmasia Alba Dolens: Appearance/Symptoms |
Massive leg swelling, pain, tenderness & cyanosis of entire extremity |
|
|
Why does Phlegmasia Alba Dolens occur? |
Arterial supply compromised as a result of massive swelling |
|
|
Trousseau Syndrome |
spontaneous iliofemoral thrombosis |
|
|
What is Trousseau Syndrome indicative of? |
Malignancy |
|
|
Where do acute DVTs occur more frequently? |
LE, originating in calf veins |
|
|
What increases incidence of UE DVTs? |
Increased use of indwelling subclavian vein catheters & dialysis access |
|
|
What under lying conditions can increase risk of acute UE DVT? |
Cancer
Trauma
Radiation therapy
Paget-Schroetter Syndrome |
|
|
Paget-Schroetter Syndrome |
Anatomical abnormalities of thoracic outlet such as cervical rib or muscular band
Results in spontaneous effort thrombosis |
|
|
What is most common source of axillosubclavian DVT in ambulatory population? |
Paget-Schroetter Syndrome |
|
|
UE DVT: Signs & Symtpoms |
Swelling
Prominent superficial veins
Vague pain |
|
|
What % of pts with acute UE DVT have pulmonary embolism? |
36% |
|
|
Superficial Thrombophlebitis |
Thrombus formation in GSV or LSV or superficial veins of UE |
|
|
Superficial Thrombophlebitis: LE presentation |
Palpable, tender cord along course of GSV or LSV w/ associated mild erythema of skin |
|
|
What % of pts w/ LE superficial thrombphlebitis at thigh level had extension into FV? |
70% |
|
|
What % of pts w/ superficial thrombosis have assoicated DVT |
20-40% |
|
|
3rd leading cause of death in US |
Pulmonary Embolism |
|
|
Mortality rate of untreated Pulmonary Embolus? |
18-38%
Drops to 8% once dx & tx |
|
|
Pulmonary Embolus: Classic Presenting Symptoms |
Hemoptysis
Pleural pain
Thrombophlebitis
Can also mimic other heart & lung disorders |
|
|
Pulmonary Embolus: Predisposing Conditions |
Prolonged immbolization
LE fractures
Surgery
Paralysis
Pregnancy
CHF
Oral contraceptives
Long-distance travel |
|
|
Diagnostic tests for diagnosis of Pulm Emb: |
Chest X-ray
EKG
Lung scan
Arterial oxygen tension
Pulmonary angiography
Echo
Multidetector CT scan
LE duplex scan to clarify undeterminate lung scan |
|
|
Primary Varicose Veins |
Hereditary or congenital
Occur most freq in Greater Saphenous System along medial thigh |
|
|
Primary Varicose Veins are result of? |
Incompetent valves of superficial venous system |
|
|
What causes prominent varicosities? |
Transmission of hydrostatic pressure from long column of blood in IVC, iliac, & femoral veins to wall of saphenous vein |
|
|
Secondary Varicose Veins |
Results due to DVT |
|
|
Chronic Venous Insurfficiency results when |
Persistent obstruction caused by incomplete recanalization or more freq valve destruction |
|
|
Post-phlebitic Syndrome |
Constant high pressure along w/ disordered interstitial fluid clearance |
|
|
Post-Phlebitic Syndrome: Presentation |
Edema (in distal extremity)
Stasis dermatitis/hyperpigmentation
Ulceration |
|
|
What causes Dermatitis & Hyperpigmentation |
Due to hemosiderin deposits from RBCs seeping into tissues |
|
|
Where do venous ulcers occur & what are they associated with? |
Occur along medial aspect of ankle/gaitor zone
Associated w/ incompetence of superficial & deep systems |
|
|
Complaints of pts w/ valve incompetence |
Heaving, aching legs after prolonged standing or sitting w/ legs in dependent position |
|
|
If no venous obstruction, what helps relieve pt's symptoms |
Leg elevation or walking |
|
|
What happens to pt's symptoms w/ DVT & valve incompetence |
Walking causes venous congestion resulting w/ leg cramping & burning that resolves upon cessation of activity |
|
|
Lyphedema |
Collection of interstitial fluid caused by lymphatic obstruction & is congenital or acquired |
|
|
Primary/Congenital Lymphedema |
Abnormality of lymphatics superficial to deep muscle fascia |
|
|
Appearance of limb w/ Primary/Congenital Lymphedema |
Painless enlargement of affected extremity
Resistant to pitting
Normal color & no venous insufficiency |
|
|
Lymphedema Preacox |
Congenital lymphedema that more frequently affects females during puberty |
|
|
What happens with activity w/ Lymphedema Preacox? |
Swelling of ankle or foot worsens w/ activity
Eventually entire leg becomes involved |
|
|
Milroy's Disease |
Hereditary form of lymphedema that occurs at birth |
|
|
Primary Lymphedema: Caused by |
Hypoplasia
Aplasia
Dilatation of superficial lymphatics |
|
|
Primary Lymphedema: Results in |
Functional obstruction w/ increases in lymphatic pressures
As lymphatic vessels dilate, valves become incompetent & result in stasis
Stasis causes interstitial fluid to increase resulting w/ greater degree of edema & fibrosis |
|
|
Secondary Lymphedema |
Acquired
Maybe due to: Malignancy Trauma Radiation Surgical procedures s/a radical mastectomy |
|
|
Obstructive Lymphedema: Onset |
Abrupt onset of unilateral swelling w/o inflammatory changes |
|
|
Lymphedema: Complications |
Cellulitis
Recurrent lymphangitis
Thickened skin
Edema |
|
|
Lymphangitis: Presentation |
Tender, swollen extremity w/ red streaking from proximal site of infection |
|
|
Inflammatory Lymphedema: Presentation |
Acute onset associated w/ fever, chills, & red, hot streaks along course of lymphatic channels |
|
|
Most Common Organism for Inflammatory Lymphedema |
Streptococcus |
|
|
Gastrocnemius veins |
Small vessels entering Pop V
Drain gastrocnemius muscle
Look like PTVs but cannot be followed to ankle since gastrocnemius muscle ends in distal 1/3 of calf |
|
|
Another name for Gastrocnemius veins |
Sural veins |
|
|
Imaging Landmarks for Tibial Peroneal Trunk |
Shadow from tibia
Shadow from fibula
Fascia (bright white reflection lining muscle) |
|
|
What adjustment needs to be made in order to compress PTVs |
Slide transducer little more medial & angle beam slightly anterior to enable probe compression |
|
|
What technique can be employed to help visualize calf veins? |
Have patient in upright position
Gravity helps distend vessel to improve vessel identification |
|
|
Transducer positioning for ATVs |
Placed in space between tibia & fibula
Locate interosseous membrane (bright white reflection between tibia & fibula)
ATVs course anterior to membrane |
|
|
Why are compressions not performed in SAG(LONG) |
Only a small slice of vein is imaged at one time & slight angulations of sound beam can make vein appear to be compressed when sound beam has simply been angled away from vessel |
|
|
5 Qualities of Flow evaluated: |
Spontaneity
Phasicity
Augmentation
Competence
Non-Pulsatility |
|
|
Spontaneous signal |
Detecting of flow signal at site of interrogation |
|
|
What does absence of spontaneous signal indicate? |
Obstruction at that site
Except calf veins |
|
|
Why is spontaneous flow not always seen in calf veins? |
Cool vasconstricted vessels will have reduced blood flow
Augmentation will help detect flow in a cool room |
|
|
Phasicity |
Venous flow varies w/ respiration
|
|
|
What occurs when a pt takes a deep breath? |
Diaphragm descends causing increased abdominal pressure & decreased venous return |
|
|
What occurs when pt exhales? |
Diaphragm rises, creating a "sucking" effect causing increase in venous return |
|
|
What does a continuous flow signal w/o respiratory variations indicate? |
Proximal obstruction from thrombus or extrinsic compression |
|
|
What does pulsatile flow signal suggest? |
Increased central venous pressure |
|
|
Augmentation: Definition |
To increase |
|
|
Why are augmentation maneuvers performed in venous exams? |
To assess presence of thrombus & to evaluate valve incompetence |
|
|
Distal augmentation |
Sample placed in Pop V
Pt foot squeezed
Flow increases |
|
|
What does an increase in flow with distal augmentation show? |
Indicates there is no obstruction between point of interrogation (pop v) & level of manual augmentation (foot) |
|
|
Proximal Augmentation |
Sample volume in Pop V
Pt thigh squeezed above knee
No flow signal should be obtained |
|
|
What does no change in flow with proximal augmentation show? |
Indicates normal valve function
Upon release of prox augmentation, flow should increase |
|
|
What is an alternative manuever to proximal augmentation? |
Valsalva
Deep inspiration followed by bearing down
Used for iliac veins |
|
|
When is valsalva contraindicated & why? |
No valsalva if thrombus seen at level of CFV or sapheno-femoral junction
Increased pressure could result in further propagation of thrombus & increase potential for pulm emb |
|
|
How is valve competence determined? |
By evaluating flow during augmentation maneuvers |
|
|
What does a flow signal obtained upon the release of distal augmentation indicate? |
Valvular incompetence |
|
|
What does a flow signal heard upon performing a prox augmentation indicate? |
Venous insufficiency or valve incompetence |
|
|
Reflux/reverse flow moving in cadual direction lasting longer than ___ indicates valve incompetence |
0.75 seconds |
|
|
What signal is seen on color evaluation upon release of distal augmentation? |
Red signal |
|
|
What type of patients will have more pulsatile flow signals? |
Those with increased central venous pressure |
|
|
What conditions cause increased central venous pressure |
CHF
TR |
|
|
CFV Sampling: Where is distal augmentation performed? What does it evaluate for? |
Performed over thigh just above knee
Evaluates for thrombus formation in FV |
|
|
CFV Sampling: Where is proximal augmentation performed? What does it evaluate for? |
Performed by pressing on pt's abdomen just below umbilicus, over common iliac vein region, or pt valsalva
Upon release, flow should increaase if no clot located between CFV & point of compression (EIV) |
|
|
FV Sampling: Prox & Distal Levels - Distal Augmentation performed ? Evaluates what? |
Squeezing foot
Evaluates flow from tibial peroneal vessels to pop vein |
|
|
FV Sampling: Prox & Distal Levels - Proximal Augmentation performed ? Evaluates what? |
Squeeze above knee
Evaluates flow from tibial peroneal vessels to pop vein |
|
|
Sample Sites for CW Doppler |
CFV
FV (P, M, D)
Pop V
PTVs at ankle level |
|
|
Acute DVT: Defined |
first 14 days after thrombus has formed |
|
|
US Appearance of fresh thrombus |
Anechoic to hypoechoic
May be difficult to visualize |
|
|
How does the appearance of thrombus change as it ages? |
Low to medium level gray echogenicity w/ rounded tip
Walls inflamed, thrombus not adhered to vessel wall increasing risk of pulmonary embolus |
|
|
Typical Sonographic Characteristics of acute DVT |
Dilated vein
Hypoechoic echogenicity
Non-compressible vein
Free-floating thrombus
Decreased or absent distal augmentation
Continuous Doppler flow signal: indicates prox obstruction |
|
|
What is used to determine degree of obstruction? |
Doppler exam |
|
|
Subacute DVT: Defined |
2 wks & 6 months |
|
|
Subacute DVT: Appearance |
Increased echogenicity
Ability to determine age is difficult
Not free-floating
Collateral vessels will begin to develop & enlarge |
|
|
Baker's Cyst |
Crescent-shape
Located medially in pop fossae close to medial head of gastrocnemius muscle
|
|
|
When is popliteal rupture considered? |
When cyst has ill-defined bordered & pointed inferior end of cyst |
|
|
Approximately how long does it take for thrombus to organize & adhere to vessel wall? |
24 to 72 hours |
|
|
When does recanalization occur? |
3 to 6 months |
|
|
Recanalization |
Flow coursing around & through thrombus by Doppler or color techniques
"Web-like appearance"
Valve incompetence seen |
|
|
Chronic DVT/Chronic Post-thrombotic Scarring: Defined |
Thrombus being present for 6 months or longer |
|
|
Chronic DVT: Appearance |
Bright echogenicity & adheres to vessel wall
May also appear similar to calcified plaque w/ posterior shadowing
Vein wall will be thickened due to scarring
Vein size reduced |
|
|
Who is at increased risk for development of new thrombus? |
Pt w/ prior episode of acute DVT |
|
|
What else is commonly seen with chronic DVT? |
Valve damage |
|
|
Appearance of Damaged Valve |
Thickened w/ shaggy appearance |
|
|
Valve Competence |
Determined by evaluating flow during augmentation maneuvers
Flow signal obtained upon release of distal augmentation indicates valvular incompetence
Flow signal heard upon performing proximal augmentation indicates venous insufficiency or valve incompetence |
|
|
Superficial Venous Insufficiency |
Performed w/ pt standing on low step stool while examining non-wt bearing leg |
|
|
Evaluation of Superficial Venous Insufficiency: Transducer Placement |
Transducer placed over CFV, GSV, & Pop V respectively
Manual calf compression is applied or one may rapidly inflate air cuff to augment flow |
|
|
When is Superficial Venous Insufficiency diagnosed? |
Reflux time of 0.75 to 1.0 sec or longer detected |
|
|
Short Saphenous Vein (SSV): Location |
Extends along posterior aspect aof calf
Passes between two heads of gastrocnemius muscle in upper calf |
|
|
Giacomini vein: Location |
Courses as continuation of SSV along posterior aspect of thigh above sapheno-popliteal junction
Termination variable, draining into GSV at thigh or groin level
May also drain directly into FV or branches of internal iliac vein system |
|
|
What function do perforating veins perform? |
Connect superficial system to deep system
Have one way valves to allow flow from superficial to deep system |
|
|
How are incompetent perforating valves identified? |
Using b-mode imaging & color &/or spectral doppler |
|
|
What is the measurement for determining competence in perforating veins? |
Incompetent > 4 mm in diameter
Competent < 3 mm in diameter |
|
|
In the thigh, what do the primary perforators connect? |
GSV to deep veins of thigh at level of common femoral vein |
|
|
Dodd's Perforators |
Located in middle 1/3 of thigh coursing between GSV or branches of GSV to FV |
|
|
Cockett's Perforators |
Located along medial calf at 6, 13, and 18 cm above medial malleolus
Connect branches of GSV to PTV |
|
|
Boyd's Perforator |
Located in upper calf about 10 cm beow knee
Courses between GSV & PTV |
|
|
Perforator Scan Protocol |
Scan pt in upright position while evaluating non-wt bearing leg
Transducer in TRV scanning from medial condyle to medial malleolus
Identify perforators as they penetrate fascia
Measure perforator, perform distal & prox augmentation to assess valve incompetence using color or spectral doppler
Abnormal -- retrograde flow towards transducer greater than 1 second
Can also scan GSV & LSV to identify incompetent perforators
Mark with I or C on skin |
|
|
Photoplethysmography/PPG |
Device w/ infrared light emitting diode mounted on probe next to phototransistor
Probe secured on skin surface by tape or velcro strap
Infrared light is transmitted into superficial tissues
Portion relfected back to phototransistor will vary w/ number of RBCs
Signal amplified to produce voltage proportional to quantity of blood in cutaneous microvasculature |
|
|
What does/doesn't PPG measure? |
Doesn't measure volume change
Info obtained related to cutaneous circulation |
|
|
What is PPG useful for evaluating? |
Digital arterial flow
Determine venous reflux
Venous insufficiency |
|
|
How is PPG performed? |
Pt sitting on side of bed w/ legs in dependent position
PPG placed on medial aspect of leg just above medial malleolus
Pt must initially keep leg & foot still
Strip chart recorder started & resting baseline displayed
Pt asked to flex foot rapidly five times & then relax foot completely
Strip chart recorder should be running entire time
Adjustments in gain & positioning of mechanical zero point are made to ensure entire tracing displayed on paper
Adjustments in chart speed may be necessary from pt to pt |
|
|
PPG Diagnostic Criteria: Normal Response to Exercise |
Normally reduction in venous volume & drop in venous presure w/ exercise of calf muscle
|
|
|
PPG Diagnostic Criteria: Refill time |
Refill time is measured from time dorsiflexion ceases to stable endpoint for at least 5 seconds
Capillary refilling time primarily function of arterial flow |
|
|
PPG Diagnostic Criteria: Competent Valves |
Refilling time fairly slow, exceeding 20 seconds
|
|
|
PPG Diagnostic Criteria: Incompetent Valves & Venous Hypertension |
Refilling time short because of venous reflux & measures less than 20 seconds |
|
|
What is used to determine if incompetence is in the superficial or deep system? |
Tourniquet test |
|
|
How is the tourniquet test performed? |
Tourniquet tied above knee
PPG performed
Tourniquet then retied below knee
PPG performed again
|
|
|
When is the superficial system incompetent? (Tourniquet above knee) |
After performing tourniquet, if refill time normalizes to greater than 20 seconds |
|
|
When is both superficial & deep system incompetent? (Tourniquet above knee) |
After performing tourniquet test, if refill time improves but not to normal levels this indicates both deep & superficial systems are incompetent |
|
|
When is superficial system incompetent? (Tourniquet below knee) |
If refill time normalizes to great than 20 seconds |
|
|
When is the deep system incompetent? (Tourniquet below knee) |
Refill time less than 20 seconds |
|
|
Air Plethysmography (APG) |
Used to assess LE volume changes that occur w/ changes in position or exercise |
|
|
Venous APG can measure: |
Calf venous volume
Venous refill time
Indirectly assess ambulatory venous pressure |
|
|
How is APG performed? |
Performed by placing air-filled cuff around entire calf
Cuff connected to air-caliberated pressure transducer & recording device
Pt lies supine w/ leg in slight external rotation w/ heel elevated 45 on support
W/ pt still, baseline recording made
Pt then asked to quickly stand w/ wt supported by opposite leg
Refilling time recorded until stable baseline reached |
|
|
Functional Venous Volume |
The stable baseline that is reached |
|
|
Normal Venous Volume (VV) |
100 - 150 mL |
|
|
Venous Volume (VV) w/ Incompetence |
100 - 350 mL |
|
|
What does the Venous Filling Index evaluate? |
Overall valvular competence |
|
|
Venous Filling Index Formula |
Ratio of 90% of VV --------------------------- Time to reach VFT 90% |
|
|
What VFI suggests superficial system incompetence? |
Between 2 and 30 mL/sec |
|
|
What VFI suggests deep venous incompetence? |
Between 7 and 28 mL/sec |
|
|
How is the evaluation of Ejection Volume performed? |
Pt asked to perform one heel raise & return to normal resting position
This activates calf muscle to decrease venous volume & measure volume of blood ejected w/ single calf contraction
Pt performs 10 heel raises to completely empty calf veins & then returns to baseline position |
|
|
How is the Normal Ejection Volume calculated? |
60% of baseline volume
EF = (EV/VV_ x 100 |
|
|
Residual Venous Volume Fraction (RVF): Calculated |
(RV/VV) x 100 |
|
|
Residual Venous Volume Fraction (RVF) measures ? |
Percentage of total calf volume remaining after exercise
normal values < 35% |
|
|
UE Evaluation: Deep Veins |
Subclavian
Axillary
Brachial Veins |
|
|
Subclavian Vein: Flow |
Spontaneous but somewhat pulsatile flow signal due to referred pulsations from heart
Flow changes seen when valsalva performed |
|
|
Brachial Vein: Flow |
Spontaneous & become more phasic |
|
|
UE Evaluation: Superficial Veins |
Basilic Vein
Cephalic Vein
Forearms veins |
|
|
Basilic Vein: Location |
Medially in axillary space to locate junction of basilic & axillary veins |
|
|
Cephalic Vein: Location |
Lateral aspect of arm |
|
|
What was gold standard fro evaluating presence of acute DVT for years |
Venography |
|
|
Venography: Definition |
Invasive procedure that is painful for pt, more expensive than duplex technology, & carries small risk for causing thrombophlebitis |
|
|
What has caused the minimized use of venography today? |
The high accuracy rate for detecting acute DVT & venous reflux w/ duplex techniques |
|
|
What was Venography used to evaluate? |
Venous abnormalities in UE, LE, IVC, Hepatic, & Renal Veins |
|
|
What could venography differentiate & assess? |
Differentiate acute vs chronic DVT
Assess intrinsic thrombus formation vs extrinsic compression |
|
|
What was Ascending Venography used to determine? |
Patency of deep system & presence of thrombus formation |
|
|
How was Ascending Venography performed? |
Placing pt in 45 degree upright position
Leg being examined is non-wt bearing
Constrast medium injected into vein in foot
Fuoroscopy & subsequent x-ray films taken to detect flow patterns & venous obstruction
Thrombus seen as filling defect w/in vein
If IVC/larger vein need evaluation, puncture of emoral or antecubital vein w/ catheter placement required.
Multiple films taken after rapid injection of contrast medium |
|
|
How is Descending Venography performed? |
Placing catheter in femoral vein & injecting contrast material w/ pt in upright position
|
|
|
What does Descending Venography evaluate for & how? |
Evaluates for valve incompetence
Since contrast material heavier than blood, it descends to distal venous valves
If valves competent, no contrast material will pass by valves
Contrast material will continue to flow distally if valvular insufficiency present |
|
|
Treatment for Acute DVT (Anticoagulant Therapy) |
Involves admitting pt into hospital on bed rest & IV heparin for 7 - 10 days & then discharging pt on oral coumadin for 3 to 6 months |
|
|
Treatment for Superficial Thrombophlebitis: Extension into Sapheno-femoral Junction |
Early aggressive anticoagulant therapy required
|
|
|
Treatment for Superficial Thrombophlebitis: If thrombus extends above knee |
High ligation of saphenous
Anticoagulant therapy implemented until pt can go to surgery to prevent further extension into deep system w/ subsequent pulm emb |
|
|
Treatment for Superficial Thrombophlebitis: Septic Thrombophlebitis |
Pt presents w/ fever, chulls, & leukocytosis
Condition requires prompt tx of IV antibiotics & excision of affected vein to prevent systemic complications |
|
|
Thrombolytic Therapy |
Dissolve thrombus
Ex. urokinase or streptokinase |
|
|
What are some complications of Thrombolytic Therapy? |
High bleeding complications
But long term post-thrombotic sequale can be reduced |
|
|
Surgical Intervention/Vena Cava Filter: Utilized for? |
Utilized when anitcoagulant therapy is contraindicated or when pt develops pulm emb despite anticoagulant therapy |
|
|
What is most common Vena Cava Filter? |
Greenfield filter
Other devices/use of caval clips & IVC ligation employed |
|
|
Vena Cava Filter Placement |
Percutaneously placed w/in IVC below level of renal veins via femoral or jugular veins
|
|
|
Support Hose |
Tx for venous insufficiency in deep system
Control high venous pressures & prevent edema |
|
|
Treatments for Ulcers |
Medicated bandage or una boot - applied to promote ulcer healing
If ulcers large/don't heal, surgerical intervention involving stripping of GSV & ligation of perforators in ulcer region |
|
|
Cockett Procedure |
Ligation of perforators behind medial malleolus as they enter deep fascia of leg |
|
|
Linton Surgical Procedure |
Involves more extensive dissection & ligation of perforators in subfascial plane |
|
|
Venous Bypass Surgery |
Can be performed but not widely used |
|
|
Venous Ablation Therapy: 2 Types & Treatment |
Endovenous Laser Ablation (EVLA)
Radiofrequency Ablation (RFA)
Treats GSV incompetence |
|
|
Venous Ablation Therapy |
Laser/radiofrequency energy delivered endovenously causes fibrotic occlusion of vein |
|
|
Venous Ablation Therapy: Indications |
Ambulatory pts w/ surface varices &/or symptoms related to superficial venous insufficiency |
|
|
Venous Ablation Therapy: Symptoms |
Leg aching/heaviness
Fatigue
Night cramps
Restless legs
Pruritus |
|
|
Venous Ablation Therapy: Role of US |
US used to map GSV
Provide guidance for placement of sheath & laser fiver/radiofrequency catheter
Monitor delivery of tumescent anesthesia
F/U success of tx |
|
|
Where does the abodminal aorta begin? |
After the aorta pierces the diaphragm |
|
|
Location of Abdominal Aorta |
Left of midline & bifurcates at level of 4th lumbar vertebral body |
|
|
Normal size of abdominal aorta |
less than 3 cm
tapers to 1 - 1.5 cm at bifurcation |
|
|
1st major branch of Abdominal Aorta |
Celiac Axis/Trunk |
|
|
What does the Celiac Axis branch into? |
Splenic & Left Gastric Arteries (to left)
Common Hepatic Artery (to right) |
|
|
2nd Branch of Abdominal Aorta |
Superior Mesenteric Artery (SMA)
Arises about 1 cm below Celiac |
|
|
Where do the renal arteries arise from? |
Just below level of SMA |
|
|
Where does the Inferior Mesenteric Artery arise from? |
Level of 3rd lumbar vertebrae
Branches off anterior aspect of AO
Smaller than SMA
Courses down to left iliac fossa where becomes superior hemorrhoidal artery |
|
|
What does the IMA become? |
Superir Hemorrhoidal Artery |
|
|
At what level does aortic bifurcation occur? |
Level of 4th lumbar vertebrae
Become Common Iliac Arteries |
|
|
Which Common Iliac Artery is longer & why? |
Right Common Iliac Artery is longer than Left
Crosses over Left Iliac Vein |
|
|
What do the Common Iliac Arteries branch into? |
Internal & External Iliac Arteries |
|
|
What does the Internal Iliac Artery/Hypogastric artery supply? |
Walls & viscera of pelvis, genitals, & innder side of thigh |
|
|
What does the Internal Iliac Artery divide into |
Anterior Artery Posterior Artery |
|
|
What does the Anterior Artery supply? |
Buttocks |
|
|
What does the Posterior Artery supply? |
Sacral canal & pelvic musculature
Important collateral pathway |
|
|
Other branches of the Internal Iliac Arteries |
Superior Vesical
Middle Vesical
Inferior Vesical
Middle hemorrhoidal
Uterine
Vaginal arteries |
|
|
External Iliac Artery courses |
Along inner border of psoas muscle from bifurcation of common iliac artery to inguinal ligament where it forms Common Femoral Artery |
|
|
2 Branches of External Iliac Artery |
Inferior Epigastric
Deep Iliac Circumflex |
|
|
CFA arises from |
External Iliac Artery beneath inguinal ligament |
|
|
CFA courses _____ to CFV |
Lateral |
|
|
SFA arises where |
About 4 cm below inguinal ligament
Arises from CFA |
|
|
SFA course |
Along mid aspect of entire thigh
|
|
|
Where does SFA become Popliteal Artery |
At the level of the adductor hiatus in the tendon of Hunter's canal |
|
|
What other vessel (which is an important collateral pathway) arises at the level of the adductor hiatus? |
Supreme Genicular Artery |
|
|
Deep Femoral/Profunda Femoris Artery (PFA) originates where |
Bifurcation of CFA |
|
|
PFA course/path |
Posterolateral at its origin & continues medial to femur |
|
|
PFA terminates where |
Distal third of the thigh as perforating artery |
|
|
PFA supplies |
Hamstrings & hip joint
Muscular branches critical collateral source in event of SFA obstruction |
|
|
Popliteal Artery: Location |
Begins at adductor hiatus after SFA gives rise to Genicular branch
Descends lateral |
|
|
Popliteal Artery: Terminates |
At popliteaus muscle |
|
|
What does the Popliteal Artery divde into |
Anterior Tibial Artery
Tibio-peroneal Trunk |
|
|
Branches of Popliteal Artery |
Superior Muscular Branches
Inferior Muscular/ Sural Branches
Cutaneous Branches
Superior & Inferior Articular Arteries |
|
|
Anterior Tibial Artery: arises from where |
Bifurcation of Popliteal Artery |
|
|
Anterior Tibial Artery: course & termination |
Between tibia & fibula
Terminates at Dorsalis Pedis Artery on anterior surface of foot |
|
|
What does tibio-peroneal trunk divide into |
Peroneal
Posterior Tibial Artery |
|
|
Posterior Tibial Artery: Course & Terminates |
Courses posterior to tibia, down to & behind medial malleolus
Terminates into Medial, Lateral, & Plantar Arteries of foot |
|
|
Peroneal Artery: Location & Terminates |
Lies adjacent to border of fibula
Terminates as External Calcanean Artery |
|
|
Plantar Arteries: Formed by what |
Formed by termination of Posterior Tibial Artery joining w/ branches of Dorsal Pedal Artery to form Plantar Arch |
|
|
What does Dorsalis Pedis Artery divide into? |
Deep Plantar Artery |
|
|
What does the Deep Plantar Artery give rise to? |
Lateral Tarsal Artery |
|
|
Where does the Lateral Tarsal Artery originate & what does it anastomosis w/ |
Originates over navicular bone
Anastomosis w/ Lateral Plantar and Lateral Malleolar branches |
|
|
Arcuate Artery: Arises from where & gives rise to what |
Arises at level of metatarsal bases
Gives rise to dorsal metatarsal branches to digits |
|
|
4 Potential Arterial Obstructions that benefit from Collateral Pathways |
SFA Obstruction
Deep Femoral Obstruction
External Iliac Obstruction
Severe Infrarenal Aortic or Iliac Obstruction |
|
|
SFA Obstruction: Collateral Pathways |
Deep Femoral to Popliteal collateral via Descending Lateral Femoral Circumflex & Genicular Arteries
May also use muscular communication between deep femoral & popliteal arteries |
|
|
Deep Femoral Obstruction: Collateral Pathways |
Flow through CFA to Superficial Iliac CIrcumflex to Lateral Femoral Circumflex
Deep Femoral & SFA anastomosis w/ Lateral Femoral Circumflex & Superior Medial & Lateral Genicular arteries |
|
|
External Iliac Obstruction: Collateral Pathways |
Lumbar/Intercostal vessels to Superficial Iliac Circumflex to Superficial Epigastric to Inferior Epigastric & Deep Iliac Circumflex
Ipsilateral Internal Iliac to Iliolumbar to Superior Gluteal through communications w/ Deep Iliac Circumflex to External Iliac |
|
|
Severe Infrarenal Aortic or Iliac Obstruction: Collateral Pathways |
If SMA & IMA patent, flow via SMA to Right & Middle Colic to Left Colic to IMA to Rectal, Hemorrhoidal, & Visceral arteries |
|
|
What does clinically apparent vascular disease result from? |
Due to destruction of normal architecture of vessel walls |
|
|
Conditions that can be the source of disturbance in normal wall structure |
Atherosclerosis
Embolus
Aneurysm
Non-Atherosclerotic lesions
Fibromuscular dysplasia
Vasculitis
Collagen Vascular Diseases
Raynaud's Syndrome
Compartment Syndromes
Compression Syndromes |
|
|
Atherlosclerosis: definition |
Progressive disease characterized by formation of plaque |
|
|
What layers of vessel walls are affected by atherosclerosis? |
Sub-endothelial
Endothelial
Intimal
Medial |
|
|
What is the early forms of plaque made of? |
Primarily lipid surrounded by elastic & collagenous tissue
Fibrous/Fibro-fatty plaque |
|
|
What can alter plaque? |
Hemorrhage
Cell necrosis
Ulceration |
|
|
What is the plaque called after it becomes altered? |
Complicated/Complex/Heterogeneous plaque |
|
|
Embolus |
Due to piece of plaque/thrombus/platelet aggregate that dislodges, travels w/in vessel & may obstruct distal vessel of smaller size |
|
|
Aneurysm: definition |
Abnormal dilation of vessel wall
Focal or diffuse |
|
|
Fibromuscular Dysplasia |
Non-atherosclerotic, non-inflammatory disease that involves small & medium sized arteries |
|
|
3 forms of Fibromuscular Dysplasia |
Intimal fibroplasia
Medial hyperplasia
Medial fibroplasia |
|
|
Medial Fibroplasia |
Most common form
Involves carotid or renal arteries |
|
|
What does medial fibroplasia cause |
Thickening of arterial wall
May result in stenosis or occlusion |
|
|
What population is medial fibroplasia seen in most frequently? |
Women of child bearing age |
|
|
Medial Fibroplasia: Angiography appearance |
Smooth, concentric lesions
"String of beads" |
|
|
Vasculitis: definition |
Inflammatory process that leads to progressive intimal proliferation & thrombosis |
|
|
Temporal/Giant Cell Arteritis |
Inflammation of medium & large sized arteries
Particularly branches of carotid |
|
|
What population is arteritis most seen in? |
Women over age of 55 |
|
|
Arteritis: Clinical Presentation |
Headaches
Fever
Anemia (which doesnt follow characteristic pattern)
High erythrocyte sedimentation rate |
|
|
Takayasu's Arteritis |
Uncommon chronic inflammatory arteriopathy of unknown etiology |
|
|
Takayasu's Arteritis: Population & Area Affected |
Young women between ages of 10 & 40
Usually involves aorta & major branches
50% of time involves pulmonary artery
|
|
|
Collagen Vascular Disease: Lupus |
Characterized by destruction of connective tissue & small blood vessels in variety of organs
Eventually organ failure occurs |
|
|
Raynaud's Syndrome |
Characterized by episodes of vasospasm resulting in closure of small arteries & arterioles of distal extremities upon exposure to cold or stress |
|
|
Compartment Syndromes |
Due to swelling w/in osteofascial compartments of arm or leg
Swelling results w/ increased intracompartmental pressure leading to decreased vascular perfusion |
|
|
Compression Syndromes |
Occur when artery is compressed by abnormal muscle or fibrous band
|
|
|
Compression Syndromes: See with what conditions |
Thoracic Outlet Syndrome
Popliteal Artery Entrapment
Adductor Canal Compression Syndrome |
|
|
Most Common Complaint in Pts w/ acute or chronic arterial disease |
Pain |
|
|
Intermitten Claudication |
Pain brought on by exercise & relieved by rest |
|
|
What causes the pain to occur? |
Occurs when there is muscle ischemia caused by reduced oxygen delivery |
|
|
Where is the site of arterial disease responsible for symptoms? |
PROXIMAL |
|
|
Pain in thigh & buttock is disease where |
Occlusive disease of aorto-iliac segment |
|
|
Cramping calf pain is disease where |
Popliteal or SFA disease |
|
|
Ischemic rest pain |
Constant pain, aching, or burning sensation in feet or toes
Intensifies at night & relieved by hanging foot over side of bed in dependent position |
|
|
What type of disease is rest pain found with? |
Advanced multi-segment arterial disease |
|
|
What is likely present w pts who have rest pain |
Tissue loss or gangrene due to insufficient tissue perfusion
Revascularization or amputation required |
|
|
Acute Arterial Occlusion |
Result of thrombus or embolus |
|
|
Acute Arterial Occlusion: Presentation |
Sudden onset of severe rest pain, pallor, paresthesia, pulselessness, & paralysis
Decreased skin temp |
|
|
What are the 5 Ps? |
severe rest PAIN
PALLOR
PARESTHESIA
PULSELESSNESS
PARALYSIS |
|
|
Cold Sensitivity/Primary Raynaud's Syndrome |
Caused by abnormal vasospasm of digital arteries in feet, toes, or fingers during cold exposure |
|
|
Primary Raynaud's Syndrome: Clinical Characterization |
Hand coolness
Pain
Numbness
Skin color changes |
|
|
3 Color Changes that occur in digits |
1st -- fingertips turn pale or white
2nd -- cyanotic or blue
3rd -- hyperemic or red |
|
|
Population most affected by Primary Raynaud's Syndrome |
70% are women |
|
|
Secondary Raynaud's Syndrome/Raynaud's Phenomenon |
Associated disorder is source of pt's symptoms
Characterized by spastic &/or obstructive arterial disease
Occlusive lesions in small arteries w/in hands seen |
|
|
Secondary Raynaud's Syndrome: Associated Conditions |
Scleroderma
Systemic Lupus |
|
|
Components of Physical Exam of Vascular Patient |
Inspection of skin for changes in color, temperature or texture
Palpitations of pulses & ascultation for bruits |
|
|
Upper Extremity: Skin Changes |
Examination of color of extremity & fingertips
Note an fingertip lesions, skin ulcerations or gangrene
Determine if there is muscle atrophy or edema |
|
|
Upper Extremity: Evaluation of |
Joint mobility
Signs of scleroderma (shiny, atrophic skin)
Motor & sensory functions of hands & fingers |
|
|
Upper Extremity: Pulse Palpation |
Palpate axillary, brachial, radial, & ulnar arteries
Diminished/absent pulse indicative of stenosis or occlusion PROXIMAL to site of exam |
|
|
Upper Extremity: Auscultation for Bruits |
Made over supraclavicular fossa to evaluate subclavian & innominate arteries |
|
|
Bruit |
Audible noise heard over artery
Usually due to stenosis which causes turbulent flow
Turbulence creates vibration of vessel wall & can be heard w/ stethoscope |
|
|
Upper Extremity: Bilateral Brachial Blood Pressures |
Difference of 20-40 mmHg from one side to another indicative of subclavian occlusive disease & possible subclavian steal |
|
|
Lower Extremity: Skin Changes |
Inspection for trophic changes due to arterial compromise
Ex: Hair loss on affected leg
Thin, smooth & shiny skin
Thick, brittle toenails
Inspection for ulceration or gangrene over pressure points
Size of extremities symmetrical w/o muscle atrophy or edema |
|
|
Lower Extremity: Skn Color |
Evaluate in multiple positions
Pallor w elevation - arterial disease Leg turns color when elevated 30-45 degrees
Dependent rubor - leg turns deep red color when hanging legs over side of bed D/t blood pooling in arterioles |
|
|
Blue toe syndrome |
Areas of discoloration or petechia lesions on toes
Occurs due to MICROEMBOLIZATION |
|
|
Lower Extremity: Motor Function |
Evaluated because ischemia reduced blood supply to distal nerve fibers |
|
|
Diabetic Neuropathy |
Contributes to impaired sensation
Sensory function assessed by touch or nail bed compression |
|
|
Lower Extremity: Pulse Palpation |
Performed over CFA, Pop, Posterior Tibial, & Dorsalis Pedis arteries & Abdominal Aorta |
|
|
Lower Extremity: Bruit Assessment |
Performed over Aorta, CFA, & Pop A |
|
|
Doppler Evaluation: Analogue |
Most common doppler instruments - pencil probe or pocket size tpe
CW devices - 2 to 10 MHz
Audible signal through speaker or headphones
Flow direction & qualitative assessment for Doppler characteristics evaluated by recording analog waveform on strip chart recorder |
|
|
Lower Extremity: Analog Waveforms obtained where |
CFA at level of inguinal ligament
SFA
Popliteal
Dorsalis pedis
Posterior tibial arteries |
|
|
Normal Doppler Characteristics: Triphasic waveform |
Sharp systolic rise
Rapid deceleration w/ flow reversal
Second forward flow |
|
|
What type of waveform is found DISTAL to site of stenosis? |
Monophasic
(Early systolic forward flow maintained but no reverse flow component) |
|
|
Abnormal Monophasic Tracing: Flow Proximal to Stenosis |
Vary depending on collateral development
If collateral channels not developed -- harsh thumping type signal observed
Collateral flow developed -- flow signal may be normal |
|
|
Pulsatility Index |
Calculated by dividing peak to peak frequency difference by mean frequency
|
|
|
What is a normal PI in the CFA? |
>= 6.0 |
|
|
What is normal PI in Popliteal artery? |
>= 8.0 |
|
|
What is normal PI in Posterior Tibial Arteries? |
>= 14.0 |
|
|
W/O SFA disease, what PI is indicative of severe aorto-iliac stenosis? |
< 4.0 |
|
|
Upper Extremity: Waveforms sampled where |
Vertebral
Subclavian
Axillary
Brachial
Radial
Ulnar |
|
|
What is UE Doppler evaluation performed in combination with? |
Other non-invasive techniques, s/a pulse volume recordings or segmental pressures |
|
|
Fast Fourier/FFT analysis |
Signal goes through analog to digital converter where it is digitized & stored in memory of microcomputer
Each digitized signal is analyzed at very rapid rate, which provides relative magnitude of each frequency component in signal
Magnitude is displayed on monitor w/ velocity on vertical axis, time on horizontal axis, & grayscale on z-axis
Both qualitative & quantitative analysis made |
|
|
What does window filling/echoes seen underneath systolic peak demonstrates what? |
Wide range of frequency shifts due to turbulent flow |
|
|
Reasons for false window filling |
Sample gate placement too close to vessel wall
Sample gate size too large
Doppler gain setting too high
Using poor Doppler angle |
|
|
Peak Systolic Velocity (PSV): Velocities for 30-49% stenosis |
150 - 200 cm/s |
|
|
Peak Systolic Velocity (PSV): Velocities for 50 - 75% stenosis |
200 - 400 cm/s |
|
|
Peak Systolic Velocity (PSV): Velocities for > 75% stenosis |
> 400 cm/s |
|
|
Velocity Ratio Measurements: Location of samples |
1st PSV proximal to site of stenosis
PSV at max site of stenosis |
|
|
Velocity Ratio: 30 - 29% stenosis |
1.5:1 - 2:1
|
|
|
Velocity Ratio: 50 - 75% stenosis |
2:1 - 4:1 |
|
|
Velocity Ratio: > 75% stenosis |
> 4:1 |
|
|
Acceleration Time (AT): How is measurement made |
Doppler waveform from CFA
Made by placing cursor @ end diastole & another cursor at peak systole
|
|
|
Acceleration Time: Measurement of >= 144ms (1.4 sec) indicates what |
Proximal or iliac disease |
|
|
Pressures: LE - taken where |
Pressure measurements taken at ankle using Posterior Tibial Artery (PTA) & Dorsalis Pedis Artery (DPA) & Brachial arteries bilaterally |
|
|
Which is normally higher, ankle systolic pressure or brachial pressure |
Ankle systolic pressure |
|
|
What does the degree of reduction in ankle pressure correlate with? |
Severity of arterial disease |
|
|
What kind of systolic ankle pressures do pts w/ severe arterial disease & ischemic rest pain have? |
< 40 mmHg |
|
|
For non-diabetic pt, at what ankle pressure do ischemic foot uclers not heal? |
< 55 mm/Hg |
|
|
For diabetic pt, at what ankle pressure do ischemic foot uclers not heal? |
< 80 mm/Hg |
|
|
What below the knee or calf pressure indicates healing with below the knee amputation? |
> 70 mmHg |
|
|
What does the absence of any Doppler flow signal below the knee indicate? |
Failure to heal |
|
|
Ankle/Brachial Index |
Ankle to brachial index obtained by dividing higher brachial pressure into higher ankle pressure on each side |
|
|
What does ABI compensate for? |
Variations in central perfusion pressure allowing for direct comparions of serial tests |
|
|
What does ABI > 0.96 indicate? |
Normal |
|
|
What does ABI < 0.5 indicate? |
Multi-level disease |
|
|
What does ABI < 0.3 indicate? |
Ischemic rest pain |
|
|
What does brachial systolic blood pressures < 100 or above 200 cause ? |
Ankle pressures in nml pt to be 25% lower than brachial pressures |
|
|
What ABI is a positive clinical response to sympathectomy procedure? |
> 0.35 |
|
|
Equipment for Segmental Pressures: |
Pneumatic cuffs of appropriate size
Manometer to measure cuff pressure
Method for detecting distal flow (CW Doppler) |
|
|
What bladder size of the cuff needs to be used to avoid cuff artifact? |
20% greater than diameter in limb which pressures are being measured |
|
|
What happens when smaller cuffs are used? |
Falsely elevated pressures |
|
|
Segmental Pressures: 3 Cuff Method |
Large 17 cm wide cuff for thihg
2 12-cm cuffs placed at calf & ankle
Single measurement above knee |
|
|
Segmental Pressures: 4 Cuff Method |
4 12-cm cuffs
2 above knee & 2 below knee at calf & ankle
|
|
|
What does the 4 Cuff Method allow differentiation of? |
Aortoiliac disease from SFA disease |
|
|
What does gradients > 20 mmhg between adjacent cuffs indicate? |
Significant arterial occlusive disease in that segment of vessel |
|
|
What does a 20 mmHg gradient between above the knee & below the knee indicate? |
Popliteal occlusive disease |
|
|
What does a gradient between high thigh & above knee cuffs indicate? |
SFA disease |
|
|
What does a gradient > 20 mmhg between below knee & ankle level indicate? |
Significant tibio-peroneal disease |
|
|
The high thigh pressure should _____ be less than brachial pressure |
NEVER |
|
|
What does an index between high thigh & brachial pressure between 0.8 & 1.2 suggest? |
Aorto-iliac stenosis |
|
|
What does an index between high thigh & brachial pressure < 0.8 suggest? |
Complete iliac occlusion |
|
|
What else can cause a reduced high thigh pressure? |
Combined stenosis of SFA & profunda femoris artery |
|
|
What is accurate segmental pressure measurements dependent on? |
Ability of cuff pressure to be transmitted through arterial wall to blood flow |
|
|
What are diabetic patients prone to? |
Medial wall calcifications that cause ABIs to falsely high |
|
|
What does an ABI > 1.35 indicate? |
Calcified arterial walls |
|
|
How are toe pressures obtained? |
Using CW Doppler or PPG device
1.9 to 2.5 cm digital cuff on great toe |
|
|
What is the normal systolic toe pressures? |
80-90% of brachial systolic pressure |
|
|
What do toe pressures > 30 mmHg predict? |
Ulcer healing |
|
|
What are normal toe brachial indices? |
> 0.8 |
|
|
What toe brachial indices is abnormal? |
< 0.66 |
|
|
When & for what are exercise testing performed? |
Performed after resting exam is complete
Evaluates pts w/ claudication |
|
|
What does an exercise test reproduce? |
Pts symptoms
Helps determine amount of disability under controlled conditions |
|
|
Treadmill test: settings |
Speed of 1.5 mph at 10% grade
Pt asked to walk for 5 minutes or until symptoms occur & force pt to stop |
|
|
What should be documented during treadmill test |
Walking time
Location of pain/symptoms |
|
|
What needs to be obtained immediately following pt stopping walking |
Ankle & brachial pressures
Doppler waveforms of CFA |
|
|
Treadmill Test: Normal Findings |
Ankle pressures remain same or increase compared to resting pressures |
|
|
Treadmill Test: Abnormal Findings |
Drop in ankle pressure |
|
|
What does the sonographer need to do if ankle pressures drop? |
continue to take ankle pressures every 2 minutes until return to pre-exercise levels for max of 10 min |
|
|
What does a drop in post-exercise ankle pressure < 60 mmHg indicate |
Significant for claudication |
|
|
What does ankle pressures that fall significantly then rise to pre-exercise levels w/in 2-6 min indicate? |
Single level stenosis or occlusion |
|
|
What does it suggest if ankle pressures remain decreased or unrecordable for up to 10 minutes? |
Multiple level arterial stenosis or occlusion |
|
|
What do symptoms w/o significant drop in ankle pressures mean? |
Not due to arterial occlusive disease |
|
|
What is an alternative to the treadmill for pts who cannot walk (cardiac disease or SOB)? |
Reactive hyperemia |
|
|
How is reactive hyperemia performed? |
Placing pneumatic cuff at thigh level & inflating cuff to 50 mmhg above resting systolic pressure
Cuff remains inflated for 3 to 5 min |
|
|
How does reactive hyperemia serve as an alternative to treadmill testing? |
Produces ischemia & vasodilatation distal to cuff
After 3 - 5 min, thigh cuff deflated & ankle pressures obtained
Transient drop in ankle pressure of up to 34% seen |
|
|
During reactive hyperemia, what does a drop in pressure < 50% indicate? |
Single level disease |
|
|
During reactive hyperemia, what does a pressure drop > 50% indicate? |
Multilevel stenosis |
|
|
What is treadmill testing the performed method? |
Creates physiologic stress which reproduces ischemic symptoms |
|
|
What are other methods of performing exercise |
Hall walking
post occlusive reactive hyperemia
Toe raises |
|
|
What are some contraindications to exercise testing |
Known or questionable cardiovascular disease
Severe pulmonary disease
Unable to walk on treadmill
Ischemic rest pain
Ischemic limb ulceration |
|
|
When is treadmill test or reactive hyperemia not necessary to perform? |
Pts w/ ischemic rest pain w/ systolic pressures < 40 mmHg & ABI < 0.35 |
|
|
What are UE pressure exams performed for |
To determine if significant arterial occlusive disease present & at what level
Usually performed in conjunction w/ doppler or plethysmography waveforms |
|
|
Segmental Pressures: Procedure |
Pneumatic cuff over upper arm to evaluate brachial artery & forearm to evaluate radial & ulnar flow
CW placed over artery of interest
Cuff inflated above systolic pressure & slowly deflated
Return of Doppler signal indicates pressure
Should be performed bilaterally (allows normal arm to used as reference & determine if asymptomatic disease) |
|
|
What does a difference > 20 mmHg between any two segments suggest? |
Arterial occlusive disease between the two level |
|
|
What does a unilateral drop in pressure of brachial artery suggest? |
Obstruction of ipsilateral innominate, subclavian, axillary, or proximal brachial artery |
|
|
What is > 20 mmHg drop in pressure in brachial artery suggest? |
Subclavian steal on side w/ pressure drop |
|
|
What is likely if systolic pressures are unusually low in both brachial arteries w/ abnormal ankle pressures? |
Bilateral proximal disease |
|
|
Modified Allen's Test |
Performed by placing CW doppler over Ulnar artery while radial artery compressed
Repeated placing CW over Radial artery while compressing ulnar artery
Repeated again by placing CW at base of each digit while compressing radial or ulnar artery |
|
|
Modified Allen's Test: What Indicates Palmar Arch being supplied by radial artery? |
Waveform/doppler signal obliterated while compressing radial artery |
|
|
Modified Allen's Test: Complete Arch Findings |
Waveform/doppler signal remains when compressing radial artery |
|
|
Modified Allen's Test: Digital Vessels |
CW at base of each digit while compressing radial or ulnar artery
Absence of pulsatile flow shows digital vessels arise form radial or ulnar artery not palmar arch |
|
|
Digital Pressures |
Obtained to assess arterial occlusive disease distal to palmar arch |
|
|
What does it mean when digital pressures are equally reduced along w/ normal wrist to digit gradient? |
Palmar circulation intact |
|
|
What does it mean if there are several digits w/ significant reduction in pressure? |
Significant arterial disease present in digital & palmar arch circulation |
|
|
What can cause distal arterial occlusive disease |
Emboli
Atherosclerosis
Buerger's disease
Vasospasm
Arthritis |
|
|
Thoracic Outlet Compression: definition |
Compression of Subclavian Artery as it emerges from throacic outlet
Combination of vascular & nervous system symptoms |
|
|
Location of Compression in Thoracic Outlet Syndrome |
Brachial plexus commences w/ vascular bundle as it courses btw first rib & clavicle
May occur due to motion between two bony structures
Congenital cervical rib or elongated transverse process can cause entrapment |
|
|
Thoracic Outlet Syndrome: Exam Technique |
Obtain resting doppler waveforms & pressure in UE vessels
Brachial or radial artery monitored by doppler or PPG of index finger while pt goes through series of arm maneuvers |
|
|
Thoracic Outlet Exam: Arm Manuevers |
Arm placed in full 90 degrees abduction
Arms elevated to 180 degrees above head
Adson Maneuver - abducting & externally rotating arm w/ pt's head turned towards arm & away from arm
Elbows at side & to back, shoulders pressed downward and back |
|
|
What occurs to Doppler signal in a positive thoracic outlet compression exam? |
Diminished or absent signal during performance of any of the maneuvers |
|
|
What will be noted if subclavian artery has become stenotic or thrombosed due to repeated trauma? |
Abnormal arterial signal seen in axillary artery
Pressure difference of 20-30 mmHg btw arms noted |
|
|
What is another possible complication of Thoracic Outlet Compression? |
Subclavian artery aneurysm
This can cause emboli occlusion of distal vessels |
|
|
What is a common source of hand & digit ischemia? |
Vasomotor disease |
|
|
What is the most frequently seen vasospastic condition of vasomotor diseases? |
Raynaud's phenomenon |
|
|
Raynaud's Phenomenon: Presentation |
Periodic episodes of vasopspasm of small arteries & arterioles when pt exposed to cold or emotional stimuli |
|
|
Raynaud's Phenomenon: Skin Changes |
1st -- pallor
2nd -- cyanosis
3rd -- rubor |
|
|
Primary Raynaud's |
Arteries normal but become occluded as result of abnormal vasospasm |
|
|
Secondary Raynaud's |
Vasospastic condition but arteries diseased
Associated with multiple systemic diseases, which are primarily collagen vascular disorders |
|
|
What is the most common collagen vascular disorder associated with Secondary Raynauds |
Scleroderma |
|
|
Scleroderma |
Chronic disease of unkown origin causing sclerosis of skin & various organs such as GI tract, kidneys, lungs, & heart
|
|
|
What organs does Scleroderma affect? |
Skin
GI tract
Kidneys
Lungs
Heart |
|
|
How is the skin affected in pts w/ scleroderma? |
Skin is taut, firm & edematous
Feels tough & leathery
May itch & become hyperpigmented |
|
|
What else can cause Secondary Raynauds? |
Repeated trauma
Buerger's disease |
|
|
Buerger's Disease |
Chronic reocurring inflammatory vascular occlusive disease seen primarily in peripheral vessels |
|
|
Buerger's Disease: Population affected |
Young, white Jewish males &/or heavy cigarette smokers |
|
|
What does the presence of an ulcer represent? |
Secondary Raynauds |
|
|
Why does primary Raynauds not get ulcers? |
They never develop enough ischemia to cause tissue loss |
|
|
Secondary Raynauds: Trauma |
Can cause partial or complete laceration of vessel wall
Vessel may thrombose or false aneurysm may develop |
|
|
Pseudoaneurysm is best evaluated how |
Duplex/color technique |
|
|
Complication of trauma: A-V Fistula |
Palpable thrill over affected area
|
|
|
A-V Fistula: Doppler proximal |
Increased arterial flow |
|
|
A-V Fistula: Doppler distal |
Decreased arterial flow |
|
|
A-V Fistula: Doppler over fistula |
Chaotic, turbulent flow w/ increased systolic & diastolic velocities
Venous signals from vein draining fistula will have increased pitch w/ more pulsatile characteristics |
|
|
Best way to exam A-V Fistulas |
duplex/color imaging |
|
|
Plethysmography |
Provides examiner w/ measurement of volume change in limb or organ |
|
|
Segmental Plethysmography: LE technique |
Utilzied to evaluate arterial disease by having pt lie supine on table w/ feet supported by sponge
Cuffs placed on thighs, calf, & ankles
Cuffs inflated in range of 10 to 65 mmHg & strip chart recording device started |
|
|
Segmental Plethysmography: LE Waveform Normal Findings |
Sharp rise to systole
More gradual deceleration into diastole
Usually prominent dicrotic notch |
|
|
Segmental Plethysmography: LE Waveform - Mild Proximal Arterial Disease |
Loss of dicrotic notch on downslope |
|
|
Segmental Plethysmography: LE Waveform - Moderate Arterial Disease |
Systolic peak delayed & becomes more rounded in appearance
Downslope bow away from baseline
|
|
|
Segmental Plethysmography: LE Waveform - Severe arterial occlusive disease |
Demonstrates pulse wave with very low amplitude
Equal upslope & downslope time or waveform may be unrecordable |
|
|
Plethysmography: Stress Testing |
Cuffs removed while pt walks on treadmill
Post exercise PVRs taken at ankle only
If aortoiliac disease suspected, thigh PVRs can be obtained |
|
|
Digital Plethymography |
Performed to evaluate digital artery occlusive disease ot pts w/ Raynaud's phenomenon
Volume & contour of digital pulse fairly comparable to digital pressures |
|
|
Digital Plethymography: Normal Findings |
Exhibits same characteristics as described in LE arteries |
|
|
Digital Plethymography: Obstruction Proximal Produces |
Rounded waveform
Slow rise to systole
Loss of dicrotic notch
Downslope bowing away from baseline |
|
|
What diseases are Peaked waveforms seen in? |
Pts w/:
Raynaud's
Buerger's
Traumatic arteritis |
|
|
Peaked Waveform: Appearance |
Rapid systolic upstroke
Anachrotic notch
Dichrotic notch located high on downslope of wave |
|
|
Raynaud's: Testing Procedure |
Warm room
H&P performed
Auscultation for bruits & pulse palpitations
Doppler/plethysmographic waveforms from each digit
When pressures & waveforms done, pts hand immersed in ice water, one at a time for 5 min or as long as pt can tolerate
Hand patted dry & digital waveforms quickly obtained
Same procedure repeated on opposite hand |
|
|
With cold sensitivity syndrome, what happens with Doppler? |
Doppler blood pressures will fall to unrecordable levels
|
|
|
How is primary Raynaud's confirmed with ice immersion? |
Peaked waveform after ice immersion w/ normal before ice exam waveform |
|
|
Raynaud's: Obstructive waveform appearance |
Rounded systolic peak & loss of dichrotic notch |
|
|
The more advanced the arterial occlusive disease, the _____ the waveform will be |
more dampened |
|
|
When is systemic disease (Scleroderma/Buerger's disease) suspected? |
If all digits suggest abnormal arterial occlusive characteristics |
|
|
What is expected if fixed digital arterial occlusion is detected? |
Intrinsic arterial disease suggested |
|
|
What is the next step when fixed arterial obstruction & hand ischemia is detected? |
Complete UE arterial exam including pressures & waveforms |
|
|
Reactive Hyperemia w/ Plethysmography |
Pneumatic cuff placed at point proximal to digits & inflated higher than systolic pressure for approximately 5 min
After 5 min, cuff rapidly deflated while strip chart recorder running
Continues until max hyperemia reached |
|
|
Reactive Hyperemia w/ Plethysmography: Normal Findings |
Pulse value will at least double w/ maximum pulse excursion ocurring w/in few second post-deflation |
|
|
Reactive Hyperemia w/ Plethysmography: Abnormal Findings - Proximal Obstruction |
Peak pulse volume will be delayed > 10 min
|
|
|
Reactive Hyperemia w/ Plethysmography: Abnormal Findings - Pulse Volume Doesn't Increase |
Peripheral arterioles may be too stiff to expand due to collagen disease
May be significant prox obstruction & vessels already max dilated to compensate for high resistance to flow |
|
|
Reactive Hyperemia w/ Plethysmography: Sympathetic Activity |
Demonstrated by having pt take deep breath
Little or no reduction in pulse volume indicates limb already effectively sympathectomized & therefore no response seen after performing surgical sympathectomy |
|
|
Sympathectomy Procedure |
Excision of part of sympathetic nervous pathways |
|
|
Lumbar Sympathectomy |
Helpful in LE vasospasm resistant to ordinary treatment |
|
|
Cervicothoracic Sympathectomy |
Offers temporary relief from Raynaud's syndrome
Rarely used |
|
|
Duplex Imaging: LE - Visualization of Vessel for |
Specific site(s) of stenosis
Number & length of stenotic segments
Plaque characteristics |
|
|
What is duplex imaging correlated with & why |
Doppler or PVR waveforms & segmental pressures
Provides accurate diagnosis & subequent pt management |
|
|
LE Duplex Imaging: Protocol |
Pt supine & leg externally rotated
Images & waveforms from: Iliac CFA SFA origin PFA origin Distal SFA Popliteal Posterior Tibial Artery
Additional images in stenotic segments
Peak systolic velocity (PSV) & Velocity Ratio Measurement made |
|
|
How can color flow assist in location of stenosis? |
Localize max site of stenosis by looking for change in color hues from dark to light
|
|
|
What do lighter shades in color hue represent? |
Higher frequency shifts |
|
|
How does multiphasic/triphasic flow display on color imaging? |
red, blue, & black color sequence indiciating intial forward flow towards transducer, followed by blue reverse flow component, and then next forward flow segment |
|
|
What does mosaic pattern in color flow represent? |
Post-stenotic turbulence |
|
|
LE Dupex: Stenosis Diagnostic Criteria - 1-19% |
Will demonstrate wall irregularities w/ mild turbulence, but no increase in peak systolic velocity |
|
|
LE Duplex: Stenosis Diagnostic Criteria - 20-49% |
Demonstrate an increase in peak systolic velocity > 30% but < 100% from segment preceding it
Reverse flow component remains
Do not have pressure gradient at rest |
|
|
LE Duplex: Stenosis Diagnostic Criteria - 50-99% |
Demonstrate > 100% increase in peak systolic velocity as compared to immediate PROX segment
Reverse flow component absent & significant spectral broadening |
|
|
LE Duplex: Total Occlusion |
No flow signals obtained even w/ lowered PRF & wall filter settings |
|
|
Settings to Adjust to r/o Possible occlusion |
Decrease wall filter & PRF settings to determine if low velocity trickle flow present
Use Color Flow Doppler, PW Doppler & Power Doppler |
|
|
Aneurysm Evaluation: Duplex Scanning |
Used to locate source of emboli
Evaluate aneurysms or pseudoaneurysms |
|
|
Aneurysm |
Focal dilation of arterial wall |
|
|
Abdominal Aortic Aneurysm: Diagnosis |
Diameter measurement > 3 cm |
|
|
Popliteal Aneurysm: Diagnosis |
Diameter measurement > 1.1 cm |
|
|
Pseudoaneurysm: What has caused an increase |
Use of diagnostic cardiac techniques & indwelling devices (balloon pumps) cause possibility of arterial wall damage w/ subsequent leaking & false aneurysm formation |
|
|
Most common complication of arterial catheterization |
Bleeding |
|
|
How is a pseudoaneurysm formed? |
Arterial wall defect persists in its communication w/ adjacent hematoma, together forming a fibrous capsule |
|
|
When can pseudoaneurysms form? |
Within days, months, or even years after initial arterial injury |
|
|
Appearance of pseudoaneurysm |
Anechoic cavity which has communication w/ adjacent artery w/ neck like appearance
Thrombus formation w/in anechoic cavity often seen |
|
|
Pseudoaneurysm: Doppler & color evaluation |
Increased velocity flow through communicating neck
Pulsatile mass w/ hx of trauma to artery |
|
|
Arterial Bypass Grafts |
Performed to provide alternative route for blood to flow around occluded segment |
|
|
Arterial Bypass Grafts: Materials used |
Dacron
Gortex
Saphenous vein segment |
|
|
What determines type of graft used |
Location & extent of stenotic segment |
|
|
Aortofemoral Grafts: Connected w/ |
Connected w/ either Common Femoral or Superficial Femoral Artery
|
|
|
Aortofemoral Grafts: Proximal Aortic Anastomosis |
End to end
End to side w/ distal anastomosis being end to end |
|
|
Fem-Fem Graft |
Used in pts that have incapacitating claudication due to unilateral iliac arterial disease
Moderate to high-risk surgical canditates |
|
|
Fem-Fem Graft: joined |
Joined w/ each CFA w/ end to side anastomosis
Placed subcutaneously just ventral to pubis |
|
|
Axillo-Femoral Grafts |
Attached to axillary & CFA
Located very superficially under skin surface & aids in evaluation of duplex techniques
|
|
|
Axillo-Femoral Grafts: Used in what type of pts |
Pts w/ bilateral iliac disease who are poor surgical candidates or in pts who have severe aortoiliac disease & abdominal collateral flow insufficient to supply legs |
|
|
Fem-Pop Grafts |
Placed in pts who have severe femoral popliteal occlusive disease that is causing disablinh claudication or threatening ischemia |
|
|
Saphenous Vein Graft |
Preferred due to better adaptability to flexion & extension of knee |
|
|
Reverse Saphenous Vein Bypass Graft |
Performed by removing saphenous vein & reversing its position to connect smaller end of femoral artery at inguinal ligament region & larger end to popliteal artery |
|
|
Reverse Saphenous Vein Bypass Graft: Connection |
connect smaller end of femoral artery at inguinal ligament region & larger end to popliteal artery |
|
|
Why is the reverse saphenous vein bypass graft placed in the position? |
Allows for venous valves to open w/o obstruction to allow arterial blood to flow down to extremity |
|
|
In-situ Saphenous Vein Graft |
Used in longer femoral to posterior tibial artery bypass grafts |
|
|
In-situ Saphenous Vein Graft: Positioning |
Saphenous vein left in its anatomical position connecting smaller end to tibial vessel & larger end placed in femoral artery |
|
|
What is used to disrupt the valves in the in-situ saphenous vein graft? |
Valvulotome (valves normally would prevent flow in vein) |
|
|
What is required to prevent the formation of A-V fistula? |
All tributary or perforating veins must be tied off |
|
|
Bypass Graft: Diagnostic Criteria - Doppler evaluation |
Doppler at each anastomotic site for obstruction as well as flow at prox, mid, distal segments of graft |
|
|
How often is graft evaluation performed? |
6 wks, 3 months, 6 months, & then annually for possible complications |
|
|
What is the velocities & ratios for PTA site residual stenosis > 50% |
Verified by duplex
PSV > 180 cm/s
Velocity ratio > 2 |
|
|
Graft Pseudoaneurysm: Appearance |
Anechoic pulsating mass adjacent to & communicating w/ artery
|
|
|
Proximal Pseudoaneurysm of Aorta |
Clinically silent but high mortality rate due to sudden rupture |
|
|
Perigraft Fluid |
Small amounts of fluid nml collect focally or at anastomotic sites during first 10 days after implantation & then gradually regress |
|
|
Procedure when Perigraft Fluid present |
Pt followed to ensure no hematoma, abscess, lymphocele, or other complication
Any fluid collection that increases or becomes symptomatic is abnml & complication |
|
|
Hematoma |
High risk for development of infection |
|
|
Process for Infected Graft |
Infected graft must be removed & infection aggressively treated bc of high associated mortality rate |
|
|
Fistula: Aortoduodenal Fistula - Most Common Location |
Between infrarenal segment of abdominal aorta & third segment of duodenum |
|
|
Aortoduodenal Fistula: US |
Fluid collection around proximal aorta |
|
|
UE Duplex Protocol |
Subclavian
Axillary
Brachial
Radial
Unar
Deep palmar arch
Digital arteries |
|
|
UE Duplex: Subclavian Artery |
Transducer in trv scan plan just above clavicle
Angle inferior to visualize vessel in sag
2D & Doppler (multiphasic waveform)
Follow vessel lateral & move below clavicle |
|
|
UE Duplex: Axillary Artery |
Pt abducts arm & transducer in axilla
|
|
|
UE Duplex: Brachial Artery |
Transducer on medial aspect of arm & aim laterally
Follow to antecubital fossae
Doppler prox, mid, distal |
|
|
UE Duplex: Radial, Ulnar, Palmar Arch, Digital Arteries |
Doppler waveforms prox, mid, distal |
|
|
Normal Subclavian & Axillary Velocities |
70 - 120 cm/s |
|
|
Normal Brachial Peak Velocities |
50 - 100 cm/s |
|
|
Normal Radial & Ulnar Velocities |
40 - 90 cm/s |
|
|
2 most Common sites for Aneurysm formation |
Subclavian & Axillary arteries |
|
|
UE Arterial Obstructions: due to |
Trauma (blunt type, arterial catheterization or drug addicts)
Emboli (A Fib, Bacterial endocarditis, MI, or heart conditions) |
|
|
2 Most frequent sites for Arterial Embolism in UE |
Brachial artery bifurcation
Middle 1/3 of brachial artery |
|
|
Atherosclerosis: Most Likely Vessels affected |
Subclavian & Axillary arteries |
|
|
Arteriography |
Invasive procedure
Not primary method of diagnosis of disease
Obtained after decision made for surgical intervention |
|
|
Arteriography: Provides |
Detailed image of arterial anatomy & disease that enables clinician to determine which therapeutic technique most appropriate |
|
|
Arteriography: Procedure |
Radiopaque material injected into artery & multiple x-ray films obtained
|
|
|
Arteriography: Quality exam dependent on |
Selecting most appropriate contrast agent, determining best radiographic projections, selecting proper injection volume, & rate of injection volume along w/ synchronization of rapid filming |
|
|
Arteriography: Performance |
Use catheter system w/ radiolucent plastic sheath w/ soft tip or Seldinger method that uses guide wire system |
|
|
4 Basic Approaches for Accessing Arterial System |
Transfemoral
Transaxillary
Brachial
Translumbar |
|
|
What determines where to access arterial system |
Distribution of disease & primary region of interest |
|
|
Arteriography: Complications |
Due to administration of contrast media or mechanical vascular injury from manipulation of catheter |
|
|
What pts are at increased risk for contrast induced renal failure |
Low renal blood flow
Diabetes
Proteinuria
Dehydration or pre-existing renal insufficiency |
|
|
What pts are at increased risk for hypotension from contrast agent? |
Pts w/ ischemic myocardial or cerebrovascular disease bc contrast agent is direct myocardial depressant |
|
|
Complications caused by contrast agents |
Source of convulsion
Cortical blindness
Frank stroke |
|
|
Arteriography: Mechanical Complications from catheter manipulation |
Bleeding (most common)
Thrombosis
A-V fistula
Pseudoaneurysm |
|
|
Interpretation of arteriogram |
By identifying arteries or segments of vessel that do not opacify |
|
|
Digital Subtraction Angiography (DSA) |
Utilizes less contrast material & relies on digitally recorded radiographic images "subtracted" from baseline image that enhances contrast areas
Multiple imaging planes implemented |
|
|
MR Angiography (MRA) |
Provide anatomic definition of occlusive disease & beneficial in preoperative planning of LE revascularization |
|
|
Time of flight (TOF) & Phase contrast MRA: Previously |
Valuable for evaluation of carotid & intracranial arteries but limited diagnostic capability for LE applications
Primarily limited due to long field of views that must be covered |
|
|
Contrast Enhanced MRA: Benefits |
Improved diagnostic capabilities for LE arterial disease
Less time consuming, easier to perform, good pt acceptance |
|
|
Contrast Enhanced MRA: Disadvantages |
Contraindicated in pts who have pacemakers
Calcifications not as distinctly displayed as w/ computed tomography
Tendency to overestimate stenosis
Image resolution lower when compared to DSA
Susceptible to artifacts such as pt motion, surgical clips, prostheses |
|
|
Computed Tomography Angiography (CTA) |
Originally only for abdominal aorta & iliac vessels
W/ upgrade to 64 slice, contrast enhanced helical CT scan provide preoperative assessment |
|
|
CTA: Provides |
Accurate determination of aneurysm size, & detect suspected rupture |
|
|
CTA: Performance |
Moving pt through CT gantry at constant speed while simultaneously rotating x-ray tube at constant speed around pt
X-ray data being collected continuously
Data reconstructed into slices, create overlapping images that allow multiplanar reformations, various 2D projections, & 3D images |
|
|
CTA: Abdominal Applications |
Contrast media power injected at rate of 2 to 4 ml/s while pt suspends breathing for up to 30 seconds
Delay time btw 50 to 70 seconds |
|
|
Arterial Occlusive Disease: Treatment |
Dependent upon location & extent of disease
Length of stenotic segment
Pts past medical hx
Whether pt good surgical candidate |
|
|
Percutaneous Transluminal Angioplasty (PTA): Procedure |
Catheter w/ inflatable non-deformable balloon at distal end inserted at site of stenosis
Balloon inflated to crack plaque & stretch medial layer of arterial wall to enlarge lumen
Best for short single stenotic lesions < 2 cm in otherwise normal artery
Best results w/ iliac arteries, but can be used for treating isolated aortic, femoral, popliteal & renal artery disease |
|
|
Atherectomy procedures |
Selectively shave & remove plaque & debris from diseased artery
Various devices available to perform procedure but technique does not improve restenosis rate compared to balloon angioplasty |
|
|
Bypass Grafts |
Performed for pts who have multiple diseased segments or long segment stenosis |
|
|
Which grafts use gortex or Dacron material? |
Above knee grafts
Fem-fem grafts
Aorto-fem grafts |
|
|
Thrombolytic Therapy |
Primary treatment for embolic or thrombotic events
Thrombolytic agents employed streptokinase or urokinase |
|
|
Thrombolytic Therapy: Technique |
Placement of indwelling arterial catheter directly into thrombus
High doses of agent are infused for 2 to 4 hours followed by repeat arteriogram
Catheter advanced further as needed w/ infusion of lower doses for prolonged period of time along w/ interval angiography
Pt continuously monitored thru/o exam along periodic hematologic evaluation |
|
|
Stent Placement |
More popular as choice for re-establishing patency in critically narrowed vessels
f/u studies help determines patency & to make sure no re-stenosis has occurred |
|
|
Abdominal AO: Location & Course |
Begins after passing through diaphragm
Lies to left of midline
Courses down to level of L4 |
|
|
At what level does the Abdominal AO bifurcate
|
L4
|
|
|
What does the Abdominal AO bifurcate into?
|
Left & Right Common Iliac Arteries
|
|
|
What is the normal diameter of aorta & what does it taper off to at bifurcation
|
Normal diameter < 3 cm
Tapers to 1.5 cm |
|
|
What type of resistance Doppler waveform does the Abdominal Aorta demonstrate?
|
High resistance Doppler waveform
|
|
|
Where in the AO is resistance less, proximal or distal?
|
Proximal
|
|
|
What first branch of the abdominal AO?
|
Celiac Artery
|
|
|
Location of Celiac Artery
|
Arises anteriorly off aorta just below level of xphoid process
|
|
|
What 3 vessels does the Celiac Artery divide into?
|
Hepatic Artery
Splenic Artery
Left Gastric Artery |
|
|
Common Hepatic Artery (CHA): Location
|
Courses towards right
Lies anterior to portal vein & adjacent to CBD |
|
|
Common Hepatic Artery: Gives Rise to What & Where
|
Gives rise to Gastroduodenal artery near porta hepatis
Changes name to Proper Hepatic Artery |
|
|
Where does the Proper Hepatic Artery enter the Liver?
|
At porta hepatis
|
|
|
What does the Proper Hepatic Artery divide into?
|
Right Hepatic Artery
Middle Hepatic Artery
Left Hepatic Artery |
|
|
Right Hepatic Artery: Location
|
Lies anterior to Portal vein & posterior to bile duct
|
|
|
What anatomical variation does 10% of the population have with the Common Hepatic Artery?
|
Common Hepatic Artery arises from the SMA instead of the celiac artery
|
|
|
Gastroduodenal Artery: Course/Location
|
Courses caudally towards posteromedial segment of duodenum & anterolateral aspect of pancreatic head
|
|
|
What is the second branch off the Abdominal AO? |
Superior Mesenteric Artery (SMA)
|
|
|
Where does the SMA arise in reference to the Celiac Artery?
|
1 cm below the Celiac Artery
|
|
|
Superior Mesenteric Artery: Course
|
Arises anteriorly off AO at slight angle
Courses inferiorly to provide blood supply to small bowel, portions of large intestine & pancreatic head
|
|
|
What does the SMA supply blood to?
|
Small bowel
Portions of large intestine
Pancreatic head |
|
|
How much separation should there be between AO & SMA?
|
< 1.1 cm between anterior wall of AO & posterior wall of SMA
|
|
|
What is increased separate (between SMA & AO) or angle of origination > 15 suspicious for?
|
Adenopathy
|
|
|
SMA: Sonographic Appearance in TRV |
Round circular vessel surrounded by bright white echogenicity
Bulls-eye sign/Target sign/Donut sign |
|
|
SMA: Sonographic Appearance in TRV |
Round circular vessel surrounded by bright white echogenicity
Bulls-eye sign/Target sign/Donut sign |
|
|
Inferior Mesenteric Artery (IMA): Location
|
Arises from anterior aspect of abdominal AO at level of L3 or L4
In LONG - small vessel arising from anterior aspect of abdominal AO just inferior to level of SMA |
|
|
Inferior Mesenteric Artery: Provides Blood To |
Descending colon Sigmoid Rectum Potential collateral pathway when mesenteric ischemia exists |
|
|
Renal Arteries: Location
|
Arises about 1cm below level of SMA |
|
|
Right Renal Artery: Course |
Posterior to IVC before entering right kidney |
|
|
Left Renal Artery: Course |
Branches lateral off the AO entering directly into left renal hilum |
|
|
What present of population has duplicate renal arteries? |
~ 15-20% |
|
|
After entering renal parenchyma, what does the segmental arteries form |
Interlobar arteries |
|
|
Interlobar Arteries: Course |
Toward cortex and form arcuate arteries Branches from arcuate arteries & course out to periphery of kidney |
|
|
Low Resistance Waveform |
Sharp acceleration into systole with gradual deceleration into diastole Flow present throughout cardiac cycle Spectral tracing - diastolic component will not touch zero baseline Clear or clean systolic window indicates normal laminary flow |
|
|
What type of vessels are low resistance? |
Vessels carrying blood to organs that require CONSTANT blood supply Ex. Liver, spleen, Kidneys |
|
|
High Resistance Waveforms |
Sharp rise to peak systole & rapid deceleration to zero baseline Little/no diastolic flow present Flow reversal in diastole common |
|
|
What type of vessels are high resistance? |
Vessels that supply blood to high resistance vascular beds Ex. SMA in fasting patients, Peripheral vessels & ECA in cerebrovascular system |
|
|
Risk Factors: Arterial Disease |
Diabetes HTN HLD Smoking |
|
|
Risk Factors: How does diabetes affect the arteries? |
Hardening of arterial wall & loss elasticity Frequently have isolated occlusions of vessels in lower legs |
|
|
Risk Factors: How does HTN affect arteries? |
Causes in increase in intraluminal arterial wall stress Contributes to development and/or progression of atherosclerosis |
|
|
Risk Factors: How does smoking affect arteries? |
Causes increase in levels of carbon monoxide in blood that irritates endothelial lining of vessel wall |
|
|
Risk Factors: How does HLD affect arteries? |
Contributing factor to development of atherosclerosis due to high saturation of lipid fats in blood |
|
|
Atherosclerosis: Characterized by Accumulation of |
Lipids Collagen Elastic & fibrous tissue Calcifications that involve intimal and medial layers of vessel wall. |
|
|
What is the early forms of plaque primarily composed of? What is it called? |
Primarily lipid in content surrounded by elastic & collagenous tissue Fibrous/Fibro-fatty plaques |
|
|
What can alter the plaque? |
Hemorrhage Cell necrosis Ulceration |
|
|
What is the plaque called once its altered? |
Complicated/Complex/Heterogeneous type plaque |
|
|
What is an embolus a result of?
|
Due to piece of plaque/thrombus/platelet aggregate which dislodges, travels upstream and may obstruct distal vessel of smaller size |
|
|
Fibromuscular Dysplasia |
Non atherosclerotic, non-inflammatory disease Involves small & medium sized arteries |
|
|
Fibromuscular Dysplasia: 3 Forms |
Intimal fibroplasia Medial hyerplasia Medial fibroplsia |
|
|
What is most common form of fibromuscular dysplasia? |
Medial fibroplasia |
|
|
Medial Fibroplasia: 2 places it involves |
Carotid or Renal arteries |
|
|
What does fibroplasia result in? |
Thickening of arterial wall which may result in stenosis or occlusion |
|
|
What population is fibroplasia most frequently seen in? |
Women, particularly of child bearing age |
|
|
What is angiographic appearance of fibroplasia? |
Smooth, concentric lesions
"string of beads" |
|
|
What is most common cause of Renovascular Hypertension? |
Atherosclerosis but may also be due to fibromuscular dysplasia |
|
|
What is the kidneys primary role in blood pressure regulation? |
Its influence on circulating plasma volume & vasomoto tone |
|
|
Renin-angiotensin system |
Complex mechanism that normally maintains homeostasis by regulating body's sodium potassium balance, fluid volume, and blood pressure under changing physiologic conditions |
|
|
What does the renin-angiotensin system regulate to maintain homeostasis? |
Body's sodium potassium balance
Fluid volume Blood pressure under changing physiologic conditions
|
|
|
What is the juxtaglomerular apparatus comprised of? |
Richly innervated smooth muscle cells that lie along afferent arterioles Cells are very sensitive monitors of perfusion pressure |
|
|
What causes the release of renin? |
Any condition that decreases the pressure will simulate release of renin into renal vein & systemic circulation |
|
|
What can cause the activation of renin-angiotension system and lead to renovascular hypertenson? |
Renal Artery Stenosis |
|
|
What is Mesenteric Ischemia? |
Life threatening condition that occurs when there is obstruction of any of the mesenteric vessels More serious conditions occur with occlusion of SMA that results in ischemia of small bowel & considered vascular emergency |
|
|
Acute Intestinal Ischemia |
Usually due to embolic or thrombotic event |
|
|
Chronic intestinal ischemia |
Due to progressive atherosclerosis, involving origin of celiac &/or SMA |
|
|
Renovascular Hypertension: BP numbers & percent of population |
5-10% of HTN population Pts who consistently have diastolic BP > 105-115 mmHg wo medication |
|
|
Acute Embolic Occlusion: Clinical Presentation |
Sudden onset pf severe abdominal pain followed by vomiting or diarrhea Abdominal distention may/not be present Leukocytosis develops quickly |
|
|
Chronic Mesenteric Occlusion: Symptoms |
Develop more gradually Mimic bowel obstructon History of post-prandial pain Weight loss Change in bowel habits |
|
|
What causes chronic intestinal ischemia? |
Progressive development of atherosclerosis that allows for collateral channels to develop |
|
|
Patient presentation for chronic intestinal ischemia when collateral development isn't sufficient |
Symptoms of post prandial pain that increases over period of weeks or months Because of pain, patients tend to eat less causing weight loss |
|
|
In the US, what is the primary cause of portal hypertension? |
Cirrhosis |
|
|
Portal Hypertension: Signs & Symptoms |
Ascites Malnutrition Progressive liver failure Possible encephalopathy LUQ fullness due to splenomegaly Dilated veins visualized due to enlargement of venous collaterals Elevated liver enzymes, AST & ALT |
|
|
Caput Medusae Sign |
When collaterals form through the umbilical vein, snake like appearance around umbilicus |
|
|
What causes cutaneous spider angiomata & palmar erethyma? |
Inability of liver to break down estrogen & other hormones |
|
|
What is atherosclersis due to? |
Increased lipid deposits in the intima If severe can cause stenosis/occlusion |
|
|
What can atherosclerosis be? (composition) |
Fibrofatty Complex Calcific |
|
|
What risk factors is atherosclerosis associated with? |
Hypertension Smoking Diabetes Hyperlipidemia |
|
|
Aneurysm: Definition |
Occurs when there is degeneration of elastic tissue within media that results with dilation, decreased wall thickness, and increased wall tension |
|
|
What does degeneration of elastic tissue within the media of an artery result in? |
Dilation Decreased wall thickness Increased wall tension |
|
|
What is the most common cause of abdominal aortic aneurysms (AAA)? |
Atherosclerosis |
|
|
What percent of US population over 60 will develop an AAA? |
5-10% |
|
|
Approximately what percent of AAA patients are symptomatic? |
75% |
|
|
How is diagnosis of AAA usually made? |
Incidental finding of painless pulsatile mass 50% of aneurysms have associated bruit |
|
|
What finding is suggestive of a rupture aneurysm? |
Unexplained abdominal or low back pain with prominent pulsation |
|
|
What is SAAVE & what is it used for? |
Screening Abdominal Aortic Aneurysms Very Efficiently One time US screening for pts who are high risk for asymptomatic AAA |
|
|
What does one time screening for AAA & surgical repair in male smokers over the age of 65 lead to? |
43% decrease in AAA-specific mortality |
|
|
AAA: High Risk Patients |
Males 65-75 who have ever smoked ( > 100 cigarettes in a lifetime) Women & men with positive family history for aneurysm or who have established medical risk factors |
|
|
2 types of Aneurysms |
Fusiform Saccular |
|
|
What is most common type of aneurysm? |
Fusiform (demonstrate gradual dilation) |
|
|
Saccular aneurysms |
Spherical Much larger ranging from 5 - 10 cm |
|
|
What makes an aneurysm have a higher incidence of rupture |
Extending into Iliac arteries |
|
|
What can partially/completely fill an aneurysm? |
Thrombus |
|
|
Normal Abdominal AO Measurement |
< 3 cm |
|
|
If AAA > 6 cm, what is 1 year survival rate |
50% |
|
|
If AAA > 7 cm, what is 1 year survival rate
|
25% |
|
|
Percent of operative mortality before rupture |
5% |
|
|
Emergent surgery mortality percentage |
50% |
|
|
US Evaluation |
3 - 5 MHz curved transducer Long & TRV obtained from level of celiac axis down to level of bifurcation |
|
|
How is AO measured? |
Wall to wall in plane perpendicular to long-axis of vessel |
|
|
What needs to be documented in presence of aneurysm? |
Size Extent of aneurysm Presence of thrombus Whether renal arteries are involved |
|
|
Iliac Artery Aneurysm: Normal Iliac Artery Measurement |
< 1 cm |
|
|
Iliac Artery Aneurysm |
Higher risk of rupture Can cause extrinsic compression on iliac vein resulting in acute DVT May also compress ipsilateral ureter causing hydronephrosis |
|
|
Thrombus: echogenicity |
Low to medium level echogenitcity |
|
|
What is thrombus associated with? |
Distal embolic events |
|
|
What happens to thrombus as it ages? |
It becomes more echogenic Fresh thrombus may have same echo properties as blood |
|
|
What is the second most common site for aneurysm formation? |
Popliteal artery 50% bilateral |
|
|
What is the most common complication of popliteal aneurysms? |
Microemboli |
|
|
US Findings of Popliteal Aneurysm |
Dilated popliteal artery with probable thrombus formation |
|
|
Aortic Dissection: what occurs |
Hemorrhage into media after initial intimal tear |
|
|
Where do most aortic dissections originate & extend which way? |
Originate in thoracic aorta Extend inferior or superior |
|
|
Typical aortic dissection patient |
Hypertensive male 40-60 years of age Marfans Disease |
|
|
Aortic Dissection: Symptoms |
Sudden excruciating pain radiating to the back |
|
|
DeBakey Models: Type 1 |
Dissection begins at the root extending entire length of arch & into abdomen |
|
|
DeBakey Models: Type 1 & 2 |
Considered most dangerous especially if extends into CCA & Subclavian |
|
|
What are most DeBakey Type 1 & 2 a result of? |
Hereditary Marfan's disease |
|
|
Marfan's Disease |
Connective tissue disorder commonly seen in tall thin double-jointed individuals |
|
|
Aortic Dissection: Subclavian Level |
Extend to descending AO but may/not continue into abdomen |
|
|
Debakey Type 3 |
Begins at lowering descending AO Extends into abdomen May be critical if reanl arteries involved |
|
|
Aortic Dissection: US Findings |
Two lumens with echogenic intimal flap Doppler/color evaluation hepful in documenting higher resistant flow in false lumen |
|
|
Surgical Intervention for Aortic Aneurysms |
Bypass graft or endoluminal aortic stent grafting |
|
|
4 Surgical Graft Procedures |
Tube grafts (limited to AO) Aortoiliac grafts Aorto-bifemoral grafts Wrapped |
|
|
Surgical Graft: Wrapped |
Native AO opened longitudinally Graft placed inside Native AO wrapped around graft |
|
|
What is appearance of graft? |
Textured & echogenic Grafts (before 1997) w/ associated plaque may be difficult to image |
|
|
Post Op US Evaluation Should Include: |
Entire graft length Stenosis assessment Aneurismal Disease Presence of fluid collection |
|
|
Where should Doppler waveforms & PSV be obtained? |
Any site of stenosis Proximal & Distal anastomotic site Run-off vessels just beyond distal anastomosis |
|
|
How much peri-graft fluid is acceptable and for how long? |
Small amount post-op lasting for a week or more Fluid should decrease over time |
|
|
When is peri-graft fluid suspicious for infection? |
Collection is large Increasing in size Echogenic |
|
|
Why has endoluminal graft stenting become more popular? |
Less invasive Requires only short hospital stay Less expensive Well-tolerated by patient |
|
|
What are grafts a combination of? |
Intravascular stent and prosthetic graft material (Goretex or Dacron) |
|
|
What determines the type & configuration of the graft used? |
Dependent upon extent of intervention required by patient |
|
|
How is the endograft held in position? |
By stent &/or hooks & barbs that serve as anchoring devices Blood flows only through graft wo communication with native AO/aneurysm |
|
|
Where is the graft usually placed? |
Just below the lowest renal artery proximally & near iliac bifurcation as possible distally |
|
|
Aortic Endograft: US Exam Looking For |
Persistent perigraft flow in aneurysm (endoleak) Measure maximum residual aneurysm sac diameter Identify stenosis or occlusion or dissection/flap |
|
|
Endograft US Exam Protocol - TRV |
TRV images of intra-aneurysm sac segment of endovascular graft Follow to superior anastomotic site, at level of renal arteries |
|
|
Endograft US Exam Protocol - LONG |
Evaluation of celiac & SMA origins Diameter of AO measured at prox aneurysm neck & used for comparison in f/u studies Entire length of graft evaluated for dissection & intimal falps |
|
|
Endograft US Exam Protocol - DOPPLER |
Proximal to endovascular graft
Intra-aneurysm portion of graft body Distal attachment site Max & min graft diameter measured |
|
|
Endograft US Exam Protocol - PERIGRAFT SAC |
Surrounds aneurysm Evaluate for flow outside of graft (endoleak) Look for thrombus formation & measure size of surrounding aneurysm |
|
|
Endograft US Exam Protocol - COLOR |
Optimize for low flow to allow greater sensitivity in detecting endoleaks If sonoloucent areas seen within clot, endoleak suspected |
|
|
True Endoleaks
|
Uniform color Doppler appearance that is reproducible Spectral waveforms - triphasic waveforms |
|
|
Pseudoleaks |
Seen early post op period Movement of non-clotted blood within aneurysm sac due to wall motion artifacts |
|
|
Endograft US Exam Protocol - MEASUREMENT |
Critical to measure AAA sac in at least two locations along length of aneurysm AP & TRV measurements taken outer to outer wall diameter Change in aneurysm > 0.5 cm in F/U period suggests endoleak |
|
|
Ruptured Aneurysm: Pt Presentation |
Excruciating abdominal pain extending to back & shock |
|
|
Ruptured Aneurysm: Most Common Site
|
Lateral wall below level of renal arteries Hemorrhage usually into posterior pararenal space May cause displacement of kidney or compress surrounding structures |
|
|
Pseudoaneurysm: Occurs due to |
Extravasation of blood outside of vessel wall into peri-vascular space |
|
|
Pseudoaneurysm: Most Common Etologies |
Post-catheterization Trauma Surgery Infection |
|
|
Pseudoaneurysm: Most common location |
CFA Rarely - abdominal AO |
|
|
Pseudoaneurysm: US Exam Findings - 2D |
Round/oval mass connected to artery by neck |
|
|
Pseudoaneurysm: US Exam Findings - Color/Doppler |
Blood entering into pseudoaneurysm w/ highest velocities occurring in neck & turbulence seen in dilated segment "to & fro" type spectral pattern seen |
|
|
Pseudoaneurysm: Treatment |
Compression of mass w/ linear array transducer for 20 min intervals until pseudoaneurysm communication closed US-guided thrombin injection treatment of choice If doesn't close, may require surgical intervention |
|
|
Renal Artery Stenosis (RAS): 2 Methods |
Direct Indirect |
|
|
RAS: Normal to Mild (RAR & PSV) |
RAR < 3.5 PSV < 180 cm/s |
|
|
RAS: < 60%, Moderate (RAR & PSV) |
RAR < 3.5 PSV > 180 cm/s |
|
|
RAS: > 60%, Severe (RAR & PSV) |
RAR > 3.5 PSV > 180 cm/s W/ post stenotic turbulence = flow limiting stenosis |
|
|
RAS: Direct Method Doppler Evaluation - Peak Systolic Velocities obtained: |
AO
Main Renal Artery - at origin - entire length until entering kidney |
|
|
How is RAR (Renal to Aortic Ratio) obtained? |
Doppler velocity sample in proximal AO Second velocity obtained at renal artery at max site of stenosis Ratio measurement is calculated as RA/Ao ratio |
|
|
What is the primary criteria for determining a normal vs stenotic evaluation includes: |
PSV (Peak Systolic Velocity) RAR (Renal to Aortic Ratio) |
|
|
What does Indirect Method of RAS interrogate? |
Segmental renal arteries Min of 3 waveforms should be obtained from different segments of kidney |
|
|
RAS Indirect Method: Normal Findings Criteria |
1) Waveform characteristics should have low-resistance profile 2) Presence of early systolic peak (ESP) or notch on the waveform 3) An acceleration time (AT) calculated by measuring from end of diastole to early systolic peak. Value should normally be < 0.07 4) An acceleration index is calculated by measuring from end diastole to the ESP. The change in velocity or (delta) V is divided by the AT. Normal value should be < 300 cm/s 5) Color evaluation should reveal flow extending all the way to the periphery of the kidney |
|
|
Resistive Index |
End diastole & peak systole measured Normal value < 0.7 Waveform exhibits low resistance profile |
|
|
Renal Transplant: Placed where |
Iliac fossae |
|
|
Renal Transplant: Vascular Connections |
Donor renal artery anastomosed end to end with internal iliac artery or end to side to external iliac artery Cadaver kidney - renal artery may be attached to Carrell's patch of AO Renal vein attached end to side to external iliac vein |
|
|
Renal Transplant: US Exam |
7.5 - 12 MHz transducer due to superficial location Assess for size, echogenicity, & fluid collections |
|
|
Renal Transplant US Exam - Timing for follow ups |
Baseline scan performed within 24-48 hours post op using sterile technique Repeat scans performed 5 - 7 days post op & then if/when clinically indicated thereafter |
|
|
Renal Transplant US Exam - Doppler |
Evaluate flow within kidney & anastomotic sites Renal Artery - low resistance flow characteristic Venous flow assessed |
|
|
Renal Transplant: Abnormal Findings/ Renal Transplant Rejection |
Pulsatility Index (PI) & Resistive Index (RI) calculations increase PI > 1.5 & RI > 0.90 indicative of acute renal allograft rejection Renal artery stenosis Renal artery thrombosis Renal vein thrombosis |
|
|
Mesenteric Evaluation: Doppler evaluation includes |
Celiac artery Common Hepatic artery Splenic artery SMA |
|
|
Celiac, CHA, & Splenic Arteries exhibit what type of waveform |
low resistance w/o evidence of significant turbulence |
|
|
Celiac Artery: PSV |
Normal PSV --> 98-105 cm/s w/ little variance in waveform pattern or PSV in fasting & postprandial pt Severe turbulence first indicator of severe prox stenosis |
|
|
SMA: what type of waveform |
High resistance waveform in fasting pt |
|
|
SMA: End diastolic velocity |
At least double in post-prandial patient Normal velocity ranges from 97 - 142 cm/s |
|
|
PSV criteria in stenosis > 70% in celiac artery & SMA |
PSV >/= 200 cm/s in celiac artery PSV >/= 275 cm/s in SMA |
|
|
IMA: What type of waveform |
High resistance pattern Normal velocities 93 - 189 cm/s |
|
|
How many vessels need to be obstructed for mesenteric ischemia to be considered? |
at least 2 Ex. Celiac & SMA |
|
|
What is mesenteric ischemia caused by? |
Occlusion of mesenteric veins SMV, PV, SV all need to be examined |
|
|
Normal Venous Appearance |
Low velocity flow that varies with respiration (phasic flow) Veins collapse & distend during normal quiet respiration |
|
|
Venous Thrombosis Appearance |
Echogenic filling of vein but fresh thrombus may be difficult to visualize since same echo characteristics of blood Doppler will reveal partially/totally occluded vessel |
|
|
Median Arcuate Ligament Syndrome/ Celiac Band Syndrome |
Non-atherosclerotic obstruction of celiac artery |
|
|
Median Arcuate Ligament of Diaphgram: Location & How it compresses |
Crosses over anterior aspect of aorta May cause extrinsic compression of celiac artery when pt i supine or during expiration |
|
|
Median Arcuate Ligament Syndrome: Patient Symptoms |
Asymptomatic |
|
|
Median Arcuate Ligament Syndrome: Treatment |
If pt symptomatic, surgery an option but success rate variable & many pts continue to have symptoms after surgery if related to psychosocial disorders |
|
|
What type of patient should be evaluated for median arcuate ligament syndrome? |
Isolated stenosis of celiac artery identified in young female pt |
|
|
Median Arcuate Ligament Syndrome: Exam Performance |
Interrogate pt in supine position during inspiration and expiration High velocity flow detected during expiration but return to nml with inspiration Pt can be examined supine & upright Results should normalize when pt placed in upright position |
|
|
IVC: Function |
Transporting blood from LE and abdominal organs to RA or heart |
|
|
IVC: Location & Course |
Begins at level of L5 after common iliac veins merge Continues superiorly coursing just to right of midline |
|
|
IVC: Size |
Varies with respiration Decrease in size with inspiration Increase in size with expiration Dilated > 2.5 cm |
|
|
IVC: Pathology Associated with Dilation |
Elevated right heart pressures Potential early warning to CHF Acute DVT Tumor invasion |
|
|
IVC: Tumor Invasion - Most Common Types |
Renal Cell Carcinoma Wilm's tumor & may extend into RA |
|
|
IVC: Acute DVT Appearance & Doppler Evaluation |
Hypoechoic to medium level echogenic material free-floating within dilated IVC Doppler - Absent/severely diminished flow Potentially life threatening situation |
|
|
IVC Filters: Placed Why & Where |
Filters placed within IVC in pts w/ DVT & recurrent emboli Wire-mesh filter usually placed below level of renal veins & serves to trap small emboli that could otherwise result in pulm emb Filter designed to trap thrombus but thrombus below filter still abnormal |
|
|
Right Renal Vein |
Exits hilum & courses anterior to right renal artery before entering IVC |
|
|
Left Renal Vein
|
Courses anterior to AO & posterior to SMA before entering IVC |
|
|
Left Gonadal Vein |
Empties into left renal vein |
|
|
Ascending Lumbar Veins |
Branches of Common Iliac Veins Course lateral to spine & posterior to psoas muscle |
|
|
What are the Ascending Lumbar Veins called Superior to the crus of the diaphragm? |
Azygos on the right Hemiazygos veins on the left |
|
|
Portal Venous System drains what |
GI tract GB Spleen Pancreas |
|
|
What percentage of blood does the Portal Venous System carry to the liver? |
up to 70% |
|
|
What is the Main Portal Vein formed by? |
Confluence of splenic vein & superior mesenteric vein "Portal-Splenic" confluence Indicates level of neck of pancreas |
|
|
Port Vein: Location & Course |
Lies anterior to IVC Courses toward porta hepatis where it bifurcates into right & left branches |
|
|
Right Portal Vein |
Usually larger than left Divides into Anterior & posterior branches which course intrasegmentally |
|
|
Left Portal Vein |
Courses towards caudate lobe Forms medial & lateral branches |
|
|
Splenic Vein |
Forms posterior border of tail & body of pancreas Continues towards right where joined by SMV to form portal vein at level of neck of pancreas |
|
|
Inferior Mesenteric Vein (IMV) |
Drains into splenic vein |
|
|
What two vessels join to form Portal Vein & at what location? |
Splenic vein & SMV Join at level of neck of pancreas |
|
|
Superior Mesenteric Vein (SMV) |
Arises in lower intestine in parallel course to SMA Seen posterior to pancreatic neck & anterior to uncinate process |
|
|
Portal Venous System: Doppler Characteristics |
Venous flow lower velocity than arterial & varies with respiration Specific measurements not made |
|
|
What is evaluated in venous flow? |
Presence Direction Quality of flow |
|
|
What kind of flow is seen in Splenic & Portal Vein? |
Low velocity demonstrated as being close to zero baseline with evidence of phasicity Flow direction should be towards liver |
|
|
Phasicity: Definition |
Flow varies with changes in respiration |
|
|
Portal Hypertension: Occurs When |
Elevated pressure in portal system |
|
|
What is most common etiology of portal hypertension in the US? |
Cirrhosis (usually due to alcohol abuse) |
|
|
Potential Anastomotic Routes in Portal Vein Obstruction |
1) Esophageal & gastric veins via coronary vein 2) Hemorrhoidal & intestinal veins 3) Splenic & left renal vein 4) Recanalization of paraumbilical vein, which connects with portal vein |
|
|
Portal Hypertension: US Evaluation |
Measure Portal Vein diameter Assess PV flow direction & velocity Assess splenic vein flow & hepatic artery flow Detect dilation of collaterals |
|
|
Secondary Signs of Portal Hypertension |
Splenomegaly Ascites Visualization of portosystemic venous collaterals Initially PV may enlarge ( > 13 mm) but normal size seen when collaterals develop Bi-directional or reverse (hepatofugal) PV flow |
|
|
Normal Portal Vein Flow |
Phasic flow towards liver (hepatopedal) with mean flow velocity of 14-18 cm/s |
|
|
Portal Vein Flow in Presence of Portal Hypertension |
Less phasic & eventually reverses with increased severity of disease |
|
|
Portosytemic Shunt Evaluation: created to |
Decompress portal system to protect pt with portal hypertension from gastroesophageal bleeding |
|
|
3 Primary Types of Portosystemic Shunts |
Portacaval Mesocaval Splenorenal |
|
|
How is assessment of flow determined in shunts? |
Doppler & color |
|
|
TIPS Procedure |
Transjugular Intrahepatic Portosystemic Shunts Involves creating a shunt percutaneously through internal jugular vein |
|
|
Pre TIPS - US Exam |
Evaluate patency & flow direction in portal, splenic, SMV, & hepatic veins Internal jugular vein patency Determine bifurcation of portal vein (w/in or outside liver parenchyma) Evaluate liver for mass or other abnormality |
|
|
Where is the TIPS shunt placed |
Connecting Right Portal Vein to middle or right hepatic vein |
|
|
TIPS - Post Procedure US |
Performed within first 24 hours after shunt placement Check patency & flow velocities in shunt & portal vein |
|
|
How often should repeat post TIPS US be performed? |
3 to 6 month intervals |
|
|
Post TIPS US Objectives
|
Detect shunt stenosis
Monophasic to slightly pulsatile flow characteristics Mild to moderate turbulence normal PSV = 90 - 120 cm/s but at least 50 - 60 cm/s |
|
|
Post TIPS US: Portal Vein Flow |
Hepatopedal with increased velocity as compared to pre-shunt values Average post-shunt portal vein velocities = 37 - 47 cm/s |
|
|
Most Common Site for Stenosis in Shunt |
Hepatic Vein branch adjacent to proximal end of stent |
|
|
US Findings w/ Shunt Stenosis |
Increased flow velocities (reported up to 400 cm/s) Reduced shunt velocity compared to baseline study < 50 - 60 cm/s Any change in velocity exceeding 100 cm/s from normal shunt segment to narrowed segment Decreased portal vein flow as compared to baseline study (< 300 cm/s) Shunt occlusion = no flow detected (sensitize machine, use power doppler to avoid missing trickle flow) |
|
|
Portal Vein Thrombosis: Most often related to what |
Neoplastic disease or inflammation secondary to intra-abdominal/pelvic infection (in adults) |
|
|
Portal Vein Thrombosis: Symptoms & Major Complaint |
Asymptomatic Ascites |
|
|
Portal Vein Thrombosis: US Appearance |
Portal Vein has low-level grey echogenicity within vessel May partially/totally occlude vessel Fresh thrombus same echo properties as blood |
|
|
Portal Vein Thrombosis: Doppler & Color Flow |
Help distinguish between benign or malignant process in patients with cirrhosis Pulsatile flow in portal vein typically seen in MALIGNANT thrombosis BENIGN thrombosis shows continuous flow pattern |
|
|
Cavernous Transformation of Portal Vein |
Periportal collaterals may develop in chronic thrombosis ( > 12 months) Numerous vessels around porta hepatis Associated with benign disease |
