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601 Cards in this Set
- Front
- Back
**What 3 vessels arise from Aortic Arch? |
Innominate/Brachiocephalic
LCCA
L Subclavian Artery |
|
**What does Innominate/Brachiocephalic Artery divide into? |
RCCA
R Subclavian Artery |
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**Most Common Anomaly of Aortic Arch? |
Common origin of innominate & L CCA |
|
*Subclavian arteries arch _____ the calvicle, ______ apex of lung, and behind the _____ muscle |
Above
In front of
Scalenus anterior |
|
**What are the most important subclavian artery branches? |
Vertebral (1st branch)
Thyrocervical
Internal thoracic (Internal mammary)
Costocervical Arteries |
|
*CCA divides into its external & internal branches usually at level of the upper border of ? |
Thyroid cartilage which forms the prominence of larynx |
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*Extracranial ICA has ____ branches |
0/no |
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*Which is larger, ICA or ECA? |
ICA |
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**1st branch of ECA is _______ artery |
Superior Thyroid |
|
**8 Branches of ECA |
Superior Thyroid Ascending pharyngeal Lingual Facial (Angular) Occipital Posterior Auricular Maxillary (infraorbital) Superficial Temporal (STA)
|
|
Mnemonic for 8 Branches of ECA |
SUsan ASked LINus For OCtavia's Phone Message Service
Some Aggressive Lovers Find Odd Positions More Stimulating |
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*Angular artery is terminal part of |
Facial artery |
|
*Infraorbital artery is terminal branch of |
Maxillary artery |
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*What does carotid sinus contain? |
A chemoreceptor sensitive to changes in O2 tension of blood that then signals necessary changes in respiratory activity to maintain homeostatis & pressoreceptors (baroreceptors) that regular heart rate. Compression can cause an increase pressure which leads to decreased heart rate. Compression can also cause decreased cerebral perfusion &/or distal embolization. |
|
**Largest of Intra-arterial connections is? |
Circle of Willis |
|
**What is the Circle of Willis? |
Hexagonal arrangement of distal ICA, anterior & posterior cerebral arteries, joined together by the anterior & posterior communicating arteries
anterior communicating --> anterior cerebral --> middle cerebral --> ICA --> posterior communicating --> posterior cerebral --> basilar --> vertebral |
|
**First branch of ICA |
Ophthalmic artery |
|
**Second & Third ICA branches |
Anterior Choroidal
Posterior Communicating Arteries |
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**What are the two terminal arteires of ICA? |
MCA
ACA |
|
**How does ICA connect w/ ECA fro collateral flow? |
3 branches of ophthalmic artery: Supraorbital Frontal Nasal arteries |
|
**Describe Periorbital Circulation |
Ophthalmic artery --> supraorbital artery --> globe to join w/ STA of ECA
Ophthalmic artery --> frontal artery, exits orbit --> forehead to join w/ STA
Ophthalmic artery --> frontal --> nasal artery --> angular --> to join w/ facial artery of ECA |
|
*What are some intracranial-extracranial anastomoses? |
ICA-ECA connections thru ophthalmic & orbital arteries
Meningohypophyseal branches & carotid-tympanic branches
Occipital branch of ECA w/ atlantic branch of vertebral
ECAs across midline |
|
**What is the most common anomaly of Circle of Willis? |
Absence or hypoplasia of one or both of communicating arteries |
|
**Why is the MCA not a collateral pathway? |
It is terminal artery |
|
*Why is STA not an intracranial collateral pathway of clinical significance? |
It not an intracranial artery |
|
**What is the tunica intima? |
Thin & smooth surface inner layer of endothelium, then base membrane, & connective tissue |
|
**What is tunica externa/adeventitia? |
Thin, white fibrous connective tissue & smooth muscle fibers all arranged longitudinally |
|
**The blood supply to vascular tissue is provided by ____, tiny layers that carry blood to walls of larger arteries |
Vaso vasorum located in adventitial layer |
|
*What happens in cardiac contraction? |
Pressure rises in left ventricle & left ventricle pressure exceeds aortic pressure, aortic valve opens, blood is ejected, and blood pressure rises |
|
**The heart pump represents what kind of energy? |
Potential (pressure) energy measure in mmHg |
|
*The blood pressure is greatest where and least where in arterial system? |
Greatest in heart & gradually decreases |
|
**What determines the amount of blood leaving arterial system/reservoir What does the amount of flow depend on? |
The same thing: arterial pressure/energy difference and total peripheral resistance |
|
*What stores some of the blood volume and the energy? |
Distended arteries |
|
**The total energy is the sum of |
Potential (pressure), kinetic (velocity), and gravitational/hydrostatic (HP) energies |
|
**In supine PT, there is ____ difference in HP between arteries & veins |
Negligible (0 mmHg) |
|
**What is the dynamic (mean) hydrostatic pressure in supine PT? |
15 mmHg (negligible) |
|
**What is the hydrostatic pressure at ankle of a standing pt? |
100 to 102 mmHg |
|
*The greater the energy difference/gradient, the ____ the flow |
Higher/great |
|
**What is Poiseuille's equation? |
Pressure = flow X resistance |
|
**What two things are required for blood flow (Q)? |
Pathway & pressure/energy difference (gradient) |
|
*Flow is ____ proportional to pressure |
Directly |
|
*Flow is ______ proportional to resistance |
Inversely |
|
*High rsistance = ________ flow rate |
Low |
|
*The lower the resistance, the ____ flow to maintain pressure |
Higher |
|
**What factors affect resistance to flow? |
Resistance = 8 x n x l / pi x r^4, where n = viscosity, l = length, & r = radius |
|
**A change in what has the most affect on resistance? |
Vessel diameter/radius |
|
*Flow is ____ proportional to radius |
Directly |
|
*Longer the vessel, the ___ the pressure required to maintain flow |
Higher |
|
**The radius of a vessel, the blood viscosity, the vessel length is _____ proportional to velocity |
Inversely |
|
**What are the two forms of energy loss? |
Viscous Inertial |
|
*In a rigid tube, energy losses are mainly |
Viscous |
|
*What is viscous energy loss due to? |
Increased friction between molecules and laminar layers |
|
*Internal friction is measured by its |
Viscosity (thickness of a fluid) |
|
**Energy is expended largely in the form of heat as the eddies and vortices work against the _____ of the blood |
Viscosity |
|
*An elevated hematocrit increases |
viscosity |
|
**What is inertia? |
The tendency of fluid to resist changes in its velocity in order to help maintain flow |
|
**What are inertial losses due to? |
Deviations from laminar flow as in changes in blood direction &/or velocity (eddy currents, turbulence, and vortices) |
|
**What type of energy loss occurs at the exit of a stenosis? |
Inertial |
|
**According to Bernoulli's equation, if kinetic energy (velocity) increaases, pressure energy? |
Decreases in order to equate the total energy amount |
|
*Velocity is ____ to pressure |
Inversely proportional |
|
*Pressure distal to a stenosis is ____ than pressure within a stenosis |
Higher |
|
*Laminar flow has an ____ distribution of frequencies at systole |
Even |
|
*Pressure gradients can be described as flow |
Separations |
|
**Where do flow separations in vessel occur? |
Geometry changes w/ or w/o disease (carotid bifurcation) & because of curves, and as in a bypass graft anastomosis site |
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*What nonsteady conditions affect fluid behavior? |
Fluid acceleration, deceleration, & rest |
|
**______ results because velocity & area are inversely proportional |
Acceleration |
|
*Flow accelerates ___ a stenosis |
through |
|
*Flow decelerates ____ to a stenosis |
distal |
|
*Laminar flow ____ downstream from a stenosis |
resumes |
|
*Diastolic reversal of flow is most likely in |
Extremity arteries at rest |
|
*How do arterioles assist w/ regulating blood flow? |
Contraction (constriction) & relaxation (dilation) |
|
*Flow reversal increases with |
Vasoconstriction |
|
**What happens during vasoconstriction? |
Pulsatile changes in small arteries are increased, while these changes are decreased in minute arteries, arterioles, and capillaries |
|
*Diastolic flow reversal may be ___ in vasodilated limbs |
Absent |
|
**Describe low resistance flow |
Continuous (steady) nature feeding a vasodilated vascular bed |
|
**What are some examples of vessels with low resistance flow? |
ICA Vertebral Celiac Post-prandial SMA Renal Splenic Hepatic |
|
**What are some examples of vessels w/ high resistance |
ECA Subclavian Aorta Fasting SMA Iliac Extremity arteries |
|
*When can a high resistance signal occur? |
Vasoconstriction at arteriolar level or from distal arterial obstruction |
|
**What cannot cause vasodilatation of high resistance bed? |
Hyperventilation |
|
**Why does reversal quality of high resistance signal disappear after a stenosis? |
Decreased peripheral resistance secondary to ischemia |
|
*How may arterial obstruction alter flow in collateral channels? |
Increased flow Reversed flow direction Increased velocity Waveform pulsatility changes |
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**In presence of total occlusion of main artery, why may there be normal flow? |
Collateral network & decrease in peripheral resistance |
|
**What is most controllable risk factor? |
Smoking |
|
**What does smoking cause? |
Irritation of endothelial lining Vasoconstriction |
|
*Where is HTN important? |
Increased incidence of coronary atherosclerosis |
|
*What is the most common arterial pathology? |
Atherosclerosis |
|
**What is atherosclerosis? |
Generalized disease that may begin in adolescence in which there is thickening, hardening, and loss of arterial elasticity beginning in intima & then media layer |
|
**What are the three major risk factors for atherosclerosis? |
Smoking HLD Family Hx |
|
**What are two less important factors? |
HTN DM |
|
**What are the most common sites for atherosclerosis? |
Carotid bifrucation (#1) Origins of brachicephalic vessel Origins of visceral vessels Aorto-iliac bifurcation CFA birfurcation SFA at adductor canal (vessel changes course) Popliteal trifurcation |
|
*What is pulsatile mass in neck usually related to? |
Tortuous common carotid rather than aneurysm |
|
**What are five types of atherosclerotic plaque? |
Fatty streak Fibrous plaque Complicated lesion Ulcerative lesion Intra-plaque hemorrhage |
|
*What is an ulcerative lesion? |
Deterioration of intimal layer's fibrous cap & may result in intraplaque hemorrhage, thrombosis, embolization |
|
*What is dissection? |
Non-atherosclerotic lesion that results from sudden tear in intima |
|
*What can happen to the collected blood on lumen? |
It may thrombose |
|
*What is an embolism? |
Obstruction of blood vessel by foreign substance or blood clot |
|
*What is an embolism composed of? |
Solid, liquid, or gas |
|
**What is most frequent cause of embolism? |
Part of plaque formation breaks loose (from atherosclerotic lesion, arteritis, or aniographic procedure) and travels distally until it lodges (most common) or may enter from outside body |
|
**What is a subclavian (vertebral) steal? |
Blood flow retrograde down the vertebral artery secondary to ipsilateral subclavian or innominate artery stenosis/occlusion, not secondary to vertebral artery stenosis occlusion |
|
**Subclavian steal is usually a ______ hemodynamic phenomenon |
Harmless |
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*Flow is stolen from the contralateral vertebral artery by way of the ____ artery |
Basilar |
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*It occurs most commonly on the ____ side |
Left |
|
**Patients are usually ______ meaning there are decreased pulses in affected arm w/ arm claudication being rare |
Asymptomatic |
|
*There is a lower brachial blood pressure difference of _____ in affected arm |
> 15-20 mmHg |
|
*What is a carotid body tumor? |
Small mass of non-atherosclerotic vascular tissue that adjoins carotid sinus between internal & external carotid arteries |
|
*How are tumors fed? |
Usually through ECA |
|
**What is fibromuscular dysplasia (FMD)? |
Multiple arterial stenosis caused by medical hyperplasia w/ collagen overgrowth |
|
**FMD is usually seen in young |
women |
|
**How is FMD diagnosed? |
"String of beads" Maybe post stenotic dilatation |
|
**What vessels is it seen in ? (FMD) |
Carotid & renal arteries |
|
*A patient undergoes carotid endarterectomy, 6 months later angiography is performed because of symptoms referable to other side. The angiogram reveals that operated carotid is significantly narrowed. The most likely cause is? |
Neointimal hyperplasia |
|
**What is neointimal hyperplasia? |
Intimal thickening from rapid production of smooth muscle cells (6 to 24 months) as response to vascular injury/reconstruction |
|
**What is TIA? |
Transient Ischemic Attack that lasts a few minutes up to 24 hours |
|
*Stenosis of what vessel presents highest risk for TIA? |
ICA |
|
*What does RIND (stroke w/ recovery) mean? |
Resolving ischemic neurologic deficit |
|
*How long does RIND last? |
More than 24 hours, like a stroke, but there is complete recovery |
|
*What is a stroke/CVA? |
Cerebrovascular accident lasting more than 24 hours w/ permanent neurologic deficit |
|
**What are the three classifications of CVA? |
Acute (sudden onset, unstable)
Stroke in evolution (symtpoms come & go, unstable)
Completed stroke (no progression or resolution, stable) |
|
**What is the incidence of new strokes per year? |
500,000 |
|
*The strongest risk factor for stroke is |
HTN |
|
*The most prevalent type of stroke is |
Ischemic (85%) |
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**After carotid bifurcation disease, the next most common source of stroke symptoms is |
Cardiac-source embolization |
|
**The cause of a right hemispheric infarct may be |
R ICA occlusion |
|
**When the source of the lesion is the ICA, the following symptoms are usually seen: |
Aphrasia Amaurosis fugax (AF) Unilateral contralateral paresthesia Anesthesia or paresis |
|
**Amaurosis Fugax (AF) can be interpreted as |
TIA |
|
**What is paresthesia? |
Pricking/tingling/numb sensation of the skin |
|
**What is hemiparesis? |
Weakness of one side |
|
**When the source of the lesion is MCA, the following symptoms are usually seen |
Aphasia
Dysphagia
More severe contralateral hemiparesis/hemiplegia
Behavior changes |
|
*A Patient describes a 30 minute episode of garbled speech. This is called |
Dysphasia |
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**A binocular distrubance that disrupts vision in half the visual field of both eyes is called |
Homonymous hemaniopia |
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*When the source of the lesion is ACA, the following symptoms are seen |
More severe leg hemiparesis or hemiplegia Incontienence Loss of coordination |
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*When the source of the lesion is the PCAs, the following symptoms are seen |
Dyslexia Coma usually w/o paralysis |
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*When the source of the lesion is in the posterior circulation (Vertebrobasilar arteries), the following symptoms are seen: |
Bilateral or global symptoms such as vertigo Bilateral ataxia (muscular incoordination) Bilateral visual disturbances (blurring, diplopia/double vision) Bilateral paresthesia or anesthesia Drop attack |
|
**What are four more vertebrobasilar insufficiency (VBI) symptoms? |
Dizziness Ectasia Syncope Dysphagia (difficulty swallowing) |
|
**What are some non-localizing symptoms with a variety of causes? |
Dizziness (with a tendecy to fall) Syncope Speech difficulty (alone) Headache |
|
**Where might a bruit be heard? |
Stenosis or dissection of carotid, subclavian, aorta, femoral, popliteal arteries |
|
*Bruits heard bilaterally, loudest low in neck, are most likely caused by |
aortic valve stenosis |
|
*Why is a bruit not heard with stenosis > 90%? |
Velocities are slowing in pre-occlusive state, and there is no longer any tissue vibration |
|
*The most important reason Doppler evaluations should be performed with patient in a basal state & warm temperature is |
Results are influenced by pt's peripheral resistance |
|
*What are some limitations of periorbital Doppler? |
Not diagnostic w/ lesions < 50% diameter reduction
Cannot differentiate occlusion from tight stenosis
Cannot establish exact location of disease
Non-diagnostic when collaterals exist
Requires considerable technical skill |
|
**How is the frontal artery (of the ophthalmic artery) evaluated? |
Use 8-10 MHz probe on inner canthus of eye to locate frontal artery
Normal antegrade flow should be noted on recorder
Ipsilateral & contralateral compression manuevers on ECA branches are performed |
|
*Flow _____ upon compression of ECA branches or low CCA is evidence of collateral development |
Reversal |
|
**What are some contraindications to OPG-GEE? |
Allergies to local anesthetics
Eye surgery within the last six months
Past spontaneous retinal detachment
Acute or unstable glaucoma |
|
**What are not contradications of OPG-GEE? |
Myopia Conjunctivitis |
|
*True or false: Plethysmography detects blood volume changes in systole but not diastole |
False |
|
**Standardization deflections should have an amplitude of approximately _____ on the chart recorder paper |
10 mm above & below the baseline |
|
*If the amplitude is not 10 mm, press ____ and adjust GAIN or press STD |
recaliberate |
|
*A pt w/ brachial systolice pressure < 140 mmHg may only require |
300 mmHg vacuum pressure |
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*A pt w/ brachial systolic pressure > 140 mmHg opr pt w/ ocular pulsations at 300 mmHg may require |
Max vacuum of 500 mmHg |
|
*Pressure in the ophthalmic artery reflects pressure in the |
distal ICA |
|
**Ophthalmic systolic pressures should not differ by more than |
5 mmHg |
|
**A normal ratio of ophthalmic to brachial systolic pressure should be |
OSP-39/BSP >= .430 |
|
**What is abnormal OPG-Gee? |
OSP's that differ by 5 mmHg or more &/or OSP-39/BSP ratio <.43 |
|
*What is least likely to produce an abnormal indirect cerebrovascular test? |
Disease in external carotid |
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*What imaging transducer frequencies would appropriately be used for carotid arterial assessment? |
5, 7.5, or 10 MHz, usually 8-10 MHz |
|
*In duplex imaging, the best arterial wall image quality is obtained when beam is at the following angle to artery walls |
90 degrees where angle of reflection = angle of incidence |
|
*What is the biggest limitation to duplex scanning? |
Acoustic shadowing |
|
*What can acoustic shadowing cause? |
Erroneous calcification of percent stenosis |
|
**How is an abnormal B-mode image interpreted? |
Fatty streaks (hypoechoic & homogenous echoes)
Soft fibrous (homogenous)
Complex plaque (heterogeneous echoes of soft & dense plaque)
Calcification
Thrombosis (same echogenicity of blood)
Surface characteristics (smooth, irregular, crater) |
|
**How can overestimation of disease occur? |
Artifact is mistaken for plaque, accelerated flow due to other causes (tortuous vessel, collateralization for ipsilateral or contralateral disease), inappropriately large doppler angle |
|
**What is the most frequent reason for underestimation of the amount of stenosis? |
Improper placement of the sample volume |
|
*What is the Doppler equation? |
Doppler frequency = 2 X transmit freq X RBC x (cos angle)/(1540m/s) |
|
*The reflected frequency is higher or lower depending on |
Direction of flow |
|
**What does the 2 represent (in the Doppler equation) |
2 Doppler shifts because the RBC is first an observer of an US field, then it acts as a wave source when struck |
|
*The angle correct cursor for velocity estimates is best |
Adjusted parallel w/ arterial walls, not adjusted 60 degrees at all times |
|
*What is the greatest source of error? |
Doppler probe > 60 degree angle |
|
*What is continuous wave (CW) DOppler? |
Two PZT crystals w/o range resolution/range gating & w/ fixed sample size |
|
**CW has ____ spectral window |
Little to No |
|
*Why is frequency open window not as apparent with CW? |
Because it cannot regulate its sample size, there is spectral broadening |
|
*In using CW Doppler w/ spectral analysis to assess the ICA, which of the following operator-induced errors would most likely result in falsely low frequency shift? |
Increasing the beam angle to 70 degrees |
|
*Non-imaging CW & PW Doppler provide |
Only physiologic information
Unable to distinguish tight stenosis from an occlusion
Information from more than one vessel may be included
Collateralized ECA may be mistaken for an occluded ICA
Must be performed by an experienced tech |
|
*The __ method allows the individual frequencies that make up the returned signal to be displayed |
FFT |
|
**____ is on the horizontal axis |
Time |
|
**____ are on the vertical axis |
Various true frequency shifts |
|
**Bilateral diminished CCA flow velocities are indicative of |
Poor cardiac output or stroke volume (cardiac insufficiency) |
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**The waveform of the _____ has a rapid upstroke and down stroke with a strong, high diastolic component |
ICA |
|
*Another name for upstroke is |
Spectral envelope |
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*A dicrotic notch may ___ evident |
not be |
|
*A high resistance signal is not |
continuous |
|
**The ___ has a rapid upstroke and down stroke with a low, almost no diastolic flow component |
ECA |
|
**How is it best to differentiate ICA from ECA? |
Waveform characteristics, vessel positions, presence of branches |
|
*During a cerebrovascular exam, you obtain equal brachial systolic pressures bilaterally. During the scan, you obtain this pulsatile signal between the transverse processes. You move the beam to the CCA and the waveform is below the baseline. This waveform suggests |
You should ask patient to perform a Valsalva manuever because it's probably a vertebral venous signal |
|
*What is the maximum Doppler shift frequency displayed? |
1/2 PRF |
|
**When might aliasing occur? |
When PRF is too low |
|
**How can PRF be increased and avoid aliasing? |
Decrease the transducer frequency, increase the angle of insonation closer to 90 degrees to decrease vessel depth, change to CW |
|
*What are Doppler shifts above & below the baseline? |
Mirror image artifact or helical (non-axial corkscrew) flow |
|
*What is mirror image artifact caused by? |
Presence of strong reflectors (B-mode) or utilizing too much gain (doppler) |
|
**Why are scan rates lower with Color Doppler? |
Multiple pulse cycles (7-20) in each color line |
|
**What is not a useful color flow adjustment in an effort to detect slow flow in a possibly occluded ICA? |
Increase color flow PRF because increasing the PRF will make the color flow less sensitive to slow flow |
|
*Diameter reduction is a ____ -dimensional measurement |
One |
|
**The two flow characteristics that define arterial stenosis anywhere in the body include focal flow acceleration velocities and |
Distal turbulence |
|
**_______ into the stneosis produced an increase in Doppler shift frequencies resulting in increased velocites |
Entrance |
|
**True spectral broadening & loss of spectral window is consistent with |
Turbulent flow |
|
*What is flow disturbance due to? |
Interrupted flow stability with high velocities and eddy currents |
|
**At stenosis _____, post-stenotic turbulence characterized by flow reversals, flow separations, vortices/eddy currents occur near edge of flow pattern |
Exit |
|
**Where can a jet of elevated velocities be found? |
Approaching a stenosis
Within a stenosis
Upon leaving the stenosis |
|
**What must be considered if there are high resistance flow patterns in the ICA? |
Disease at the carotid siphon |
|
**A low resistance pattern is present in many arteries except |
Proximal ICA in presence of siphon high-grade stenosis |
|
**A hemodynamically significant stenosis usually begins w/ a CSA reduction of ___ which corresponds to a diemter reduction of 50% |
75% |
|
*What diagnostic criterion is anticipated in the presence of a 50-60% diameter stenosis of the ICA? |
Elevation of systolic frequency w/ post-stenotic turbulence due to pressure & flow gradients |
|
**What is the range of Doppler diagnostic guidelines? (stenosis: normal, PSF, EDF, PSV, EDV) |
PSF: < 4 kHz EDF: PSV: < 125 cm/s EDV |
|
**What is the range of Doppler diagnostic guidelines? (stenosis: 1-15%, PSF, EDF, PSV, EDV) |
PSF: < 4 kHz EDF: PSV: < 125 cm/s EDV |
|
**What is the range of Doppler diagnostic guidelines? (stenosis: 16-49%, PSF, EDF, PSV, EDV) |
PSF: < 4 kHz EDF: PSV: < 125 cm/s EDV |
|
**What is the range of Doppler diagnostic guidelines? (stenosis: 50-79%, PSF, EDF, PSV, EDV) |
PSF: > 4 kHz EDF: < 4 kHz PSV: > 125 cm/s EDV: < 140 cm/s |
|
*What does an occluded vessel look like? |
Varying degrees of echogenic material, vessel completely filled w/ echoes, vessel motion is piston-like or horizontal |
|
**The loss of a diastolic component proximally in ipsilateral CCA is consistent w/ |
ICA occlusion |
|
*What are some conditions in which TCD might be useful? |
Vasospasm following subarachnoid hemorrhage Determination of brain death Cerebral artery monitoring during surgery Carotid siphon stenosis |
|
**What size transducer is used? |
2 MHz PW |
|
**What angle of insonation is assumed? |
0 degrees |
|
**What are the main three acoustic windows? |
Transtemporal Transorbital Transforaminal/suboccipital |
|
*The _____ approach allows for three windows: anterior, middle, and posterior |
Transtemporal |
|
**What is the standard method of quanitfy velocity measurements? |
Time-averaged maximum velocity (TAMV), not peak velocities |
|
**What is the technique for a TCD exam? |
Unilateral transtermporal approach & identify MCA, ACA, PCA, and terminal ICA (gives most information)
Ipsilateral transorbital approach & identify ophthalmic artery & carotid siphon
Repeat on contralateral side
Foramen magnum/subocciptal approach & identify the vertebral & basilar arteries |
|
**What artery is not evaluated? |
Posterior communicating because of inappropriate Doppler angle |
|
**How are the TCD vessels evaluated: MCA (Window, Depth, Direction, Velocity, Angle) |
Window: transtemp Depth: 30-60 mm Direction: antegrade Velocity: 55 +/- 12 cm/s Angle: Anterior & Superior |
|
**How are the TCD vessels evaluated: Distal ICA (Window, Depth, Direction, Velocity, Angle) |
Window: Transtemp Depth: 55-65 mm Direction: bidirectional Velocity: 55 +/- 12 cm/s Angle: Anterior & Superior |
|
**How are the TCD vessels evaluated: ACA (Window, Depth, Direction, Velocity, Angle) |
Window: Transtemp Depth: 60-80mm Direction: retrograde Velocity: 50 +/- 11 cm/s Angle: anterior & superior |
|
**How are the TCD vessels evaluated: PCA (Window, Depth, Direction, Velocity, Angle) |
Window: Transtemp Depth: 60-70 mm Direction: antegrade Velocity: 39 +/- 10 cm/s Angle: anterior & superior |
|
**How are the TCD vessels evaluated: ICA (Window, Depth, Direction, Velocity, Angle) |
Window: transorbit Depth: 60-80 mm Direction: antegrade/retrograde Velocity: 47 +/- 14 cm/s Angle: varies |
|
**How are the TCD vessels evaluated: Ophthalmic Artery (Window, Depth, Direction, Velocity, Angle) |
Window: Transorbit Depth: 40-64 mm Direction: antegrade Velocity: 21 +/- 5 cm/s Angle: Medial |
|
**How are the TCD vessels evaluated: Vertebral Artery (Window, Depth, Direction, Velocity, Angle) |
Window: Transforam Depth: 50-90 mm Direction: retrograde Velocity: 38 +/- 10 cm/s Angle: R & L of midline |
|
**How are the TCD vessels evaluated: BasilarArtery (Window, Depth, Direction, Velocity, Angle) |
Window: transforam Depth: 80-120 mm Direction: retrograde Velocity: 41 +/- 10 cm/s Angle: midline |
|
**Using the temporal window, you find a strong signal w/ considerable diastolic flow at a depth of 50mm. This is most likely |
MCA |
|
*If a TCD exam has a spectral waveform labeled "suboccipital window", and depth is 90 mm, this vessel is most likely |
Basilar artery |
|
**What does TCD interpretation incorporate? |
Flow depth Flow direction Flow velocity Turbulence Pulsatility Systolic upstroke Hemispheric index of MCA/ICA |
|
**What is not incorporated in TCD interpretation? |
The amount of spectral broadening |
|
**How does collateralization occur? |
Antegrade flow in the ACA via the contralateral ACA
Retrograde flow never occurs in MCA
Retrograde flow in the Ophthalmic artery from external-to-internal collateralization through the ipsilateral Ophthalmic artery,
Increased flow velocities in the PCA through posterior-to-anterior collateralization through the ipsilateral PCA |
|
*Diagnosis of occlusion is most accurate in |
ICA & MCA |
|
**What is one example that is not a main collateral pathway in the event of ICA obstruction? |
Genicular to arcuate branches because genicular arteries are around the knee (genuflect), and arcuate arteries are in the kidney |
|
*The diagnosis of vasospasm is most accurate in |
MCA |
|
**How is vaospasm diagnosed? |
Serial recordings of increased mean velocities > 120 cm/s w/ a hemispheric ratio index (MCA TAMV/distal extracranial ICA TAMV) > 3 |
|
*What does a pinging noise mean? |
Microembolization |
|
*How is an intraoperative TCD interpreted? |
Decrease in MCA flow during cross-clamping may signal a need for shunting |
|
**What are some limitations to an arteriogram? |
Contrast (iodine) allergy
Renal failure
Inaccurate as a functional (hemodynamic) assessment
Unable to provide multiple images in multiple planes |
|
**What are the most common arteries used? |
CFA
Axillary
Brachial |
|
*Which is the safest approach? |
CFA |
|
**How is an arteriogram interpreted? |
Extent & location of filling defect, aberrant anatomy |
|
**What are common locations for atherosclerotic plaque? |
The adductor canal (#1 location), origins of vessels at arch, other bifurcations |
|
**How is diameter reduction calculated? |
{(1-diameter of residual lumen)/Diameter of true lumen} x 100 D = 5 mm, d = 1.5 mm 1-(1.5/5) x 100 (1-.3) x 100 .7 x 100 = 70% |
|
**How is diameter reduction calculated? |
{(1-diameter of residual lumen)/Diameter of true lumen} x 100 D = 8 mm, d = 2 mm 1-(2/8) x 100 (1-.25) x 100 .75 x 100 = 75% |
|
**How is area/cross-sectional reduction calculated? |
Assuming lesion is symmetrical, {1-(d squared/D squared)} x 100 Ex. 1 -2 squared/8 squared x 100 = 1 - 4/64 x 100 = 1 - .06 x 100 = .94 x 100 = 94% |
|
**What is critical stenosis? |
50% diameter (75% area) reduction |
|
**What are complications of an arteriogram? |
Puncture site hematoma
Pseudoaneurysm
Local arterial occlusion
Neurologic complications |
|
**What is not a common complication of arteriography? |
Nerve damage |
|
*What is unique about digital substraction arteriography (DSA)? |
A mask, often w/o contrast, is selected to be subtracted from the frames obtained during injection of contrast solution |
|
**MR Angiography (MRA) functions by processing |
Radio frequency pulses/energy created by tissue and blood, and a strong magnetic field |
|
*MRA uses ____ radiation |
Non-ionizing |
|
**MRA's are useful for what diagnoses? |
Abdominal aortic aneurysm (AAA) in determining aortic diameter, & dissection |
|
**What are the limitations of MRA? |
Metalic (surgical) clips
Pacemakers
Monitors
Claustrophobia
Expense |
|
**What aren't MRAs able to assess degree of stenosis? |
Stenosis may be overestimated due to slow flow or turbulence, resulting in loss of magnetic signal |
|
*What is CT's most frequent application in CV disease? |
Evaluate nature of: cerebral infarctions Intracranial aneurysms Hemorrhage AV malformations |
|
*CT is more accurate than what two modalities in diagnosing aneurysms? |
Arteriography & MRA because the IV contrast allows for more discreet evaluation |
|
**The most common medical treatment of acute ischemic stroke consists of |
Recombinant tissue plasminogen actrivator (rtPA) within three hours of onset of symptoms |
|
*What are some lifestyle modifications? |
Stop smoking
Increase exercise
Control weight
Low-cholesterol diet
Protection to prevent injury/infection |
|
**The NASCET trail indicated that the best treatment for carotid stenosis in the symptomatic patient is |
Carotid endarterectomy for stenosis greater than 70% in diameter |
|
**The shape of veins is determined by the |
Trasmural pressure = pressure within vein minus pressure outside of vein |
|
*What caries 2/3 of the blood in the body? |
Extra-pulmonary veins |
|
*What are the components of calf muscle pump? |
Leg muscles & venous valves |
|
**What happens in muscle pump during contraction? |
The calf ("venous heart") muscle contracts, squeezing blood in soleal sinuses from superficial to deep system resulting in decreaed venous pressure, decreased venous pooling (volume), increased venous return to heart, increased cardiac output |
|
**During inspiration, there is venous return from the ___ extremities |
Upper |
|
**What happens during valsava? |
Both intra-thoracic & intra-abdominal pressures increase, and venous return is halted |
|
**What are venae comitantes? |
Corresponding veins referring to close proximity to its accompanying artery |
|
**The radial, ulnar, & brachial veins are |
Paired venae comitantes |
|
**Where do the radial & ulnar veins form the paired brachial veins? |
Near elbow |
|
**The brachial veins become axillary vein at confluence of basilic vein in the |
axilla |
|
*The digital veins form the cephalic vein on the ____ aspect of the forearm |
Lateral |
|
*The digital veins form the basilic vein on the ___ aspect of the forearm |
medial |
|
**The axillary vein becomes the subclavian vein at the confluence of the ___ vein |
cephalic |
|
**The subclavian vein joins the IJV's to form the ____ veins in the neck bilaterally |
Brachiocephalic/Innominate |
|
**What forms the deep venous arches? |
The deep digital veins that form the metarsal veins |
|
*What are the paired veins of the LE? |
ATVs
PTVs
Peroneal veins
Gastrocnemius veins |
|
*Which veins empty the back of the leg? |
P(osterior)TVs |
|
**What are the venous sinuses of the LE? |
Located in the dilated, saccular muscular (soleal & gastrocnemius) veins that are a major part of the calf-muscle pump, they serve as reservoir spaces and drain blood into the PTVs, peroneal, and popliteal veins |
|
**Where does most DVTs begin? |
The soleal veins |
|
**A thrombus is found in a large, muscular soleal vein, a bit proximal to mid calf. If this were to propagate, it would next involve? |
Posterior tibial &/or peroneal veins, & not popliteal veins |
|
*Where are the peroneal veins located? |
A few cm up calf and deeper than PTVs in lateral leg |
|
**A thrombus is found in gastrocnemius vein approximately 1/3 of the way down calf from knee. If this were to propagate proximally, it would next involve? |
Popliteal vein |
|
*The CFV becomes the ___ just above the inguinal ligament |
EIV (External Iliac Vein) |
|
**Why is there more left DVT than right DVT? |
Left iliac vein passes under left liac artery causing an extrinsic compression point |
|
*What is the longest vein in the body? |
GSV |
|
*What is the purpose of perforating veins? |
To empty blood from superficial system into the deep system |
|
*Where is the posterior communicating branch of GSV that is connected to perforator? |
Medial lower calf |
|
**Why are the two perforators of the PTVs at medial malleolus so important? |
Site of venous stasis ulceration |
|
**The superficial vein that receives flow from the three main perforating veins od the distal calf/ankle is called |
Posterior arch vein |
|
**Why is the posterior arch vein important? |
It is a site for venous ulceration |
|
*The aorta is to the ____ of the midline; the IVC is to the ____ |
Left, right |
|
**Describe the SVC |
Formed by confluence of right & left innominate/brachiocephalic veins & drains head & UEs |
|
**What are venous valves? |
Bicuspid extensions of initimal layer |
|
**What are some veins without valves? |
Soleal sinuses
External iliac vein (75% of time)
Common Iliac
Interal Iliac
Innominate
SVC
IVC |
|
*What are some veins w/ valves? |
GSV (10 - 12 below knee)
LSV/SSV (6 - 12)
Perforators (1 each)
Infrapopliteal (7 - 12 each)
Popliteal & SFV (1 - 3 each)
Extenal iliac (25% of time)
CFV (1)
Jugular Vein (1) |
|
*Valves of the lower extremity are more susceptan the UE due to |
Venous thrombosis
Increased ambulatory venous pressure
Increased intra-abdominal pressure &/or venous obstruction |
|
**The development of venous thrombosis is based on |
Virchow's Triad = (Endothelial) trauma, stasis, hypercoagulability |
|
**What may venous stasis be caused by? |
Immobility (bed rest, paraplegia)
MI
CHF
Hypotension
COPD
Obsesity
Pregnancy
Previous DVT
Extrinsic compression
Surgery
Fractured hips
Multiple injuries |
|
*What are some causes of hypercoagulability? |
Pregnancy
Cancer
Hormones (Estrogen)
Myeloproliferative disorders |
|
**What are diseases that are not risk factors for DVT? |
Lymphangitis
Diabetes
Smoking (when not on birth control)
Arthritis |
|
**What is the most common sequeala of DVT? |
Valvular destruction |
|
*Approximately what percentage of untreated calf vein DVT is thought to propagate to a proximal level (i.e. popliteal or above)? |
15-20 or 28% |
|
**What are some complications of DVT? |
Venous insufficiency
Venous hypertension
Pulmonary embolism (PE) |
|
*What are the most common findings in chronic venous obstruction? |
Swelling
Heaviness
Discoloration
Ulcers
Varicosities |
|
*Where does chronic venous insufficiency come from? |
As clot prpagates, flow restrictions cause increased venous pressure, stretching the walls, and damaging the valves |
|
**What happens in vavular incompetence? |
Blood flows antegrade and retrograde (venous reflux)
Increased pressure in the veins
Increased venous pooling
Decreased return to heart
Decreased cardiac output |
|
**What is ambulatory venous hypertension? |
Increased LE venous pressure when pt is standing or walking |
|
*The greatest pressure of venous hypertension occurs |
During muscle contraction |
|
**Venous hypertension MOST often results from |
Deep venous reflux |
|
*What can ambulatory venous hypertension result in? |
Edema
Hyperpigmentation
Ulcer formation |
|
**What is the most consistent sign of elevated venous pressure? |
Edema |
|
**Edema from venous disease occurs because of |
Increased capillary pressure due to an obstructive process |
|
*What is a result of incompetent perforators? |
Blood from deep veins backs up into superficial veins |
|
*______ may leak into surrounding tissue secondary to increased pressure |
Fluid
RBCs
Fibrinogen |
|
**What is the result? |
The increased venous pressure interferes with normal cellular activity resulting in brawny (toughened & swollen) discoloration from the breakdown of stagnant RBCs into hemosiderin, & ulcer formation |
|
**What is post-thrombotic syndrome (Post-phlebitic syndrome)? |
Result of chronic venous hypertension usually secondary to DVT w/ complaints of leg swelling, pain, & hyperpigmentation |
|
*What is venous claudication? |
Complication of post-phlebitic syndrome w/ chronic obstruction of ilio-femoral veins causing severe pressure & thigh pain relieved w/ rest & elevation |
|
*The effects of gravity & walking can precipitate |
Edema
Varicosities (varices)
Ulcer formation |
|
*A varicose vein is most often |
a dilitation of the greater saphenous vein or superficial tributary |
|
*________ varicose veins are caused by valvular incompetence of the superficial veins |
Primary |
|
** _____ varicose veins are caused by incompetence of the superficial system resulting from DVT & incompetence of perforators & the deep system |
Secondary |
|
*What are three examples of congenital venous disease? |
Avalvular veins
AV malformations (AVMs)
3 syndromes |
|
** A person with pulm emb might have |
Chest pain
Reduced arterial blood gasses
Diaphoresis
SOB
Tachypnea
Pleural effusion |
|
**What is a lung perfusion scan? |
A VQ (ventilation quotient/ventilation perfusion) scan to look for Pulm Emb |
|
*What are limitations of VQ scan? |
Other disorders that can cause perfusion defect
Emphysema
Asthma
Pneumonia
Bronchial cancer
CHF
Liver cirrhosis
Radiography
Multiple blood transfusions
Post-operative period |
|
**What is better than a VQ scan? |
Pulmonary angiogram |
|
**What is better than a VQ scan? |
Pulmonary angiogram |
|
**What is the "gold standard" for Pulm Emb? |
Pulmonary angiogram |
|
**Pts complaining of pain, swelling, erythema of LE may have DVT, but vascular tech knows that dx DVT by these symptoms alone is approximately |
46 - 62% accurate |
|
**What does the differential diagnosis include? |
Muscle strain
Direct injury
Muscle tear
Baker's cyst
Cellulitis
Lymphangitis
Extrinsic compression
CHF
Complications of chronic venous insufficiency |
|
**What are the most common findings for DVT, in order? |
Swelling
Pain
Redness
Warmth |
|
*Edema caused by DVT is characterized by |
Swelling in ankles & legs but not the feet |
|
*Some time after being hit by a car, pt has severe pain in anterior aspect of right knee & massive left LE edema. The pt most likely has |
Extensive left fempop DVT |
|
*What is a Baker's cyst? |
Synovial fluid from knee joint |
|
*Typical findings of skin discoloration in pt w/ chronic venous insufficiency are |
Rusty brown color at ankles & calves |
|
*Symptoms of chronic venous insufficiency does not result from |
Gastrocnemius muscular insufficiency |
|
*What is pallor due to? |
Phlegmasia alba dolens |
|
*What is phlegmasia alba dolens? |
Limb-threatening arterial spasms secondary to extensive, acute ilio-femoral thrombosis with leg edema & pain |
|
*A condition that presents as severely swollen, blue, cool LE is called |
Phlegmasia cerulean dolens (venous gangrene) from hypoxia |
|
**What is phlegmasia cerulean dolens due to? |
Limb-threatening severely reduced venous outflow from ilio-femoral thrombosis which reduces arterial inflow |
|
**A patient presents with acute pronounced bright red discoloration & edema of skin along anterior calf. The most likely diagnosis is |
Cellulitis |
|
**Patients suspected of having venous disease may complain of pain that is |
Relieved by elevation |
|
*Pitting edema of both LEs is likely related to |
Cardiac or systemic origin |
|
*Complaints of chronic unilateral LE swelling, aching, and a sense of heaviness most likely suggest |
Postphlebitic syndrome |
|
*A pt presents w/ unilateral chronic swollen leg & previous diagnosis of DVT three years earlier. The most likely finding would be |
The popliteal vein is patent & the valves are incompetent |
|
*What is non-pitting edema result of? |
One cause is lymphedema as a result of obstruction in lymphatic system |
|
*What is lymphedema? |
When lymph nodes &/or lymph vessels are removed (as in cancer surgery) or damaged as in trauma, infection, inflammation, radiation or chemotherapy, and fluid accumulates |
|
**How are venous ulcers distinguished from arterial ulcers |
Venous ulcers are at medial malleolus, have uneven, shallow edges, mild pain, with signs of stasis dermatitis & venous ooze
Arterial ulcers are over a bony prominence (tibia, toes); have regular, well-defined, deep edges; with signs of trophic changes; severe pain |
|
*LE ulcers are overwhelmingly the result of |
Venous disease |
|
*A complete venous duplex exam should include |
Venous compression & Doppler evaluation |
|
*The subclavian vein is evaluated from the _____ approach to outer border of the first rib |
Supraclavicular |
|
**What is the most important criterion in identification of deep veins? |
Adjacent artery |
|
**What is preferred method of evaluating vein wall compressibility? |
Gentle pressure w/ probe, vessel in trv view wo color flow |
|
**What are the four main venous blood flow characteristics of LEs? |
Spontaneity
Phasicity
Augmentation w/ distal compression
Augmentation during proximal release |
|
**When is pulsatile venous flow evident? |
Primarily in pts w/ fluid overload such as CHF |
|
**Subclavian venous signals are more |
Pulsatile |
|
**How does the UE signal differ from LE signal? |
In UE, more limited vessel compressibility, phasicity increases w/ inspiration, and decreases w/ expiration |
|
**In LE, phasic venous sound ____ with expiration & decreases w/ inspiration |
Increases |
|
**Augmentation w/ distal compression ____ in the UE veins |
may not be evident |
|
**Normally flow should ______ following Valsalva maneuver |
Augment |
|
**Decreased augmentation following Valsalva indicates |
Obstruction |
|
**What are the characteristics of acute DVT? |
Dilated vessel
Low echogenicity
Spongy texture
Poor attachment to wall
Lack of collateralization or recanalization |
|
*What is least likely to be associated with acute DVT? |
Probably venous reflux as it is a sequela to acute DVT |
|
**What is consistent w/ a proximal iliac obstruction? |
Diminished velocities
Compressible femoral vein w/ evidence of rouleau formation
Poor augmentaton at CFV w/ release of Valsalva |
|
*A pt presents w/ a right swollen extremity, Duplex imaging demonstrates patency of femoral, popliteal, & calf veins. However, Doppler at CFV level on the right is continuous, not changing w/ respiration, while Doppler of left CFV is phasic. These findings might suggest |
Proximal obstruction: right iliac thrombosis |
|
*A ______ color PRF setting is necessary to accommodate slower flow in LE veins |
lower |
|
*Most often, the settings for venous color flow imaging of LEs are ____ those for abdominal venous scanning |
different from |
|
*If there is no color filling of a vein, what must be considered? |
DVT
Poor angle of insonation
Highpass filter set too high |
|
*What is a contraindication to this study? |
cardiac arrhythmias |
|
**What are some limitations to CW evaluation? |
Difficult to differentiate thrombosis from extrinsic compression (obesity, pt positioning)
Normal flow patterns may be evident w/ partial or well-collateralized thrombosis
Presence of bifed system
Difficult to diagnose calf vein DVT due to presence of paired veins
Severe PAD
Potentiality of false positives
Must be performed by extremely experienced tech |
|
*How can tech diminish extrinsic compression? |
By having pt lay on left side to reduce compression of IVC |
|
*In a CW venous Doppler exam, which flow characteristic is least important? |
Non-pulsatility as pulsatility is related to CHF, not venous disease |
|
**How can there be false positives? |
Extrinsic compression
Pain or anxiety causing muscle contraction
PAD causing decreased venous filling
COPD can elevate central venous pressure
Operator error |
|
**How can there be false negatives? |
Partial thrombosis
Chronic occlusion w/ large collaterals
Presence of bifed system |
|
**How long does venous reflux last to be called true venous reflux? |
Longer than 1 second |
|
*The examiner uses color flow to assess for competence at CFV level. With Valsalva maneuver, there is red flow lasting approximately half a second, then blue flow on release of Valsalva |
This finding is equivocal for significant valvular incompetence as most labs use 1 second rule |
|
*Augmentation or flow reversal during Valsalva indicates |
Reflux secondary to valvular incompetence |
|
*In sagittal view, color Doppler shows GSV as blue. During a Valsalva maneuver, the vessel is filled with red. What does this signify? |
Valvular incompetence |
|
*In fact, what is contraindication for PPG study? |
A pt w/ DVT |
|
*What are some limitations to PPG study? |
Placement of PPG over varicose vein
Thick skin may reduce infrared light penetration
Skin must be intact
Obesity |
|
**Light is transmitted/emitted from a |
Light emitting diode |
|
**The backscattered infrared light is received by adjacent |
Photodetector/photo-sensor/photocell |
|
*What is the sensor? |
The infrared light |
|
*Blood ____ light in proportion to its content in tissue |
Attenuates |
|
*A light is emitted & reflected back. Is it absorbed? |
No |
|
*What does the photocell do? |
Measures the reflection of light qualitatively |
|
**What is DC coupling? |
An electrical voltage that is either positive or negative with current flowing in only one direction to permit slower changes in the blood content to be evaluated in venous studies |
|
*Car and flashlight batteries are |
DC |
|
**A short venous refilling time (VRT of 20 seconds) detected by PPG results most commonly from |
Venous reflux |
|
**How is superficial venous insufficiency diagnosed? |
VRT < 20 seconds w/o tourniquet, & > 20 seconds w/ tourniquet above the knee |
|
*What are examples of artifact? |
Pt mvement
Absent/irregular tracings from system from being on AC
Off-the-scale-deflections that require changes in gain |
|
**What is the other test for reflux? |
Air plethysmorgraph (APG)
Trendelenburg test
Pneumoplethysmography |
|
** _____ are usually evident superimposed on the tracing of venous flow |
Tiny arterial pulsations |
|
*What are the physical principles/key technology of APG? |
Pneumatic cuff is connected to a pressure transducer monitoring cuff pressure over a limb; volume changes amplified & converted to analog |
|
*Why are the tip-toe maneuvers performed? |
To document a decrease in calf venous volume (VV), calculated as the ejection volume (EV) and the venous filling time (VFT) |
|
**How is the APG study interpreted? |
Venous filling index (VFI) = 90% VV/VFT x 90
< or = 2.0 is normal
> or = 10.0 is severe reflux |
|
*What is residual fraction volume (RFV)? |
Ambulatory venous pressure in mmHg |
|
*Insufficient veins have the following flow characteristics: |
Caudal flow may be abnormal while the pt is quietly standing
Venous pressure at ankle in the supine pt does not differ from that of nml limbs
Venous pressure at the ankle in the walking pt is markedly increased compared to that of nml limbs |
|
*With exercise in pts w/ post-phlebetic syndrome |
they have a prolonged return to pre-exercise pressure |
|
**(Contrast) venography is still considered to be the ___ for DVT |
Gold standard |
|
*What is ascending venography? |
Evaluate acute & chronic DVT
Congenital venous disease &/or anomalies |
|
**What is descending venography |
To detect & quantify reversed flow from incompetent valves |
|
*Where is the contrast injected for descending venography |
CFV |
|
**What are the advantages of isotope venography w/ I-labeled fibrinogen? |
Can simultaneously evaluate the pulmonary and peripheral veins
Is highly sensitive to active thrombus
Is extremely accurate in detecting an isolated calf clot |
|
*What are some lifestyle modifications to prevent venous disease? |
Control risk factors related to Virchow's triad:
Decrease venous stasis
Prevent injury/infection
Be aware of hyperocoagulability states/factors |
|
*Low dose heparin is administered prophylactically to |
Slow the conversion of prothrombin to thrombin
Increase the effect of antithrombin III
Decrease platelet adhesiveness to interfere w/ clot |
|
*Is low-dose heparin antilytic? |
No |
|
**What does the heparin do? |
Decrease clot propagation by increasing activated PTT (Partial thromboplastin time) |
|
**How is the IV dose regulated? |
So that the PTT is 1.5 - 2 times normal |
|
**Heparin can cause |
Thrombocytopenia
Formation of platelet antibody
Intraabdominal bleeding
Platelet aggregation |
|
**Nearing the end of heparinization, Coumadin (sodium Warfarin) is started for how long? |
3 to 6 months |
|
*What are some vena caval filters called? |
Greenfield umbrella filter
Bird's nest filter
Nitinol filter
Vena Tech filter |
|
*When is a filter used? |
In those pts at risk for PE and who cannot be anticoagulated |
|
**When is ilio-femoral thrombectomy performed? |
In a pt w/ impending limb loss (phlegmasia cerulean dolens) when urokinase & streptokinase do not work |
|
*What is performed for chronic venous insufficiency? |
Ligation of perforators |
|
**What artery becomes axillary artery? |
Subclavian Artery |
|
*How many branches of axillary artery are there before becoming the brachial artery? |
Seven |
|
**The radial artery gives off what branch in the hand? |
Superficial palmar branch |
|
*The radial artery terminates into what artery? |
Deep palmar arch (by joining deep branch of ulnar artery) |
|
**The ulnar artery terminates into what artery? |
Superficial palmar arch |
|
*What is another name for palmar? |
Volar |
|
**The ________ passes under inguinal ligament to become CFA |
EIA |
|
**The SFA passes through what opening? |
In the tendon of adductor hiatus (adductor canal, Hunter's canal) |
|
*What does the popliteal artery give off which can act as collaterals? |
Genicular branches |
|
*What is the first branch of distal popliteal artery? |
ATA |
|
**This artery passes forward above interosseous membrane and distally comes to lie deep on the front of tibia |
ATA |
|
**The short tibio-peroneal trunk divides into what two vessels? |
Posterior Tibial Artery & Peroneal Artery |
|
*What is the largest branch of PTA? |
Peroneal Artery |
|
**The PTA divides into what two vessels below the medial malleolus |
The medial & lateral plantar arteries |
|
**The _______ artery is medial to the fibula |
Peroneal |
|
**The ATA becomes what vessel? |
The dorsalis pedis artery (DPA) |
|
**What is an important branch of DPA? |
Deep plantar artery |
|
**What does the plantar arch consist of? |
The deep plantar artery which unites w/ lateral plantar artery |
|
*What are the smallest vessels in body, the vessels of microcirculation? |
The capillaries |
|
*What is the diameter of a capillary? |
8-10 microns, about the same as RBC |
|
*What are the capillary walls made of? |
One-cell thick endothelial cells |
|
*Capillaries lose fluid through the ______ end and reabsorb fluid through the _______ end |
Arteriolar, Venular |
|
*What is not a risk factor? |
Hypolipidemia |
|
*Why is diabetes important as a risk factor? |
Increase in atherosclerosis at a younger age, higher incidence of disease in distal popliteal & tibial arteries, medial calcification in LE arteries, higher incidence of gangrenous changes & amputations, neuropathy leading to increased injury |
|
*In the presence of arterial obstructive disease & digital ischemia |
Vasodilatation increases & distal resistance decreases |
|
*The most common source of upper or lower extremity peripheral arterial embolus is |
the heart |
|
*What produces "blue toe syndrome" |
Ulcerated &/or atherosclerotic lesions, embolization, arteritis (which can lead to thrombosis), & some angiographic procedures |
|
*What happens w/ blue toe syndrome? |
The embolic material lodges in digital artery & results in toe ischemia |
|
**Where is the most common site of an aneurysm? |
Infrarenal aorta, then thoracic aorta, femoral, popliteal, & renal arteries |
|
**What causes aneurysms? |
Unknown, may be congenital (#1 reason), atherosclerosis (degenerative), poor arterial nutrition, infection/inflammation (syphillis), or trauma |
|
*What is a fusiform aneurysm? |
Diffuse, circumferential dilatation of arterial segment |
|
*What is saccular aneurysm? |
Localized out-pouching of artery, resulting from wall thinning & stretching |
|
**What is dissecting aneurysm? |
An aneurysm that occurs when small tear of the inner wall allows blood to form a cavity between two layers most often in thoracic aorta |
|
**What is the main complication of aneurysm? |
Rupture of aorta or distal embolization of peripheral aneurysms |
|
*With which type of aneurysm, aortic or peripheral, can thrombosis occur? |
either one |
|
**What is arteritis? |
Inflammation of arterial wall often resulting in thrombosis & sometimes superficial thrombophlebitis |
|
**Where does arteritis occur? |
Capillaries, arterioles, tibial, & peroneal arteries |
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**What is the most common form of arteritis? |
Buerger's disease (thromboangitis obliterans) & is associated w/ heavy smoking in med < 40 years old |
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*What are some of the symptoms of thromboangitis obliterans? |
Bilateral rest pain & ischemic ulcerations |
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*A condition that causes nonatherosclerotic narrowing of brachiocephalic arteries in overwhelmingly female Asian patients is called |
Takayasu's arteries |
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**What is primary Raynaud's syndrome? |
Raynaud's disease
Spastic Raynaud's syndrome
It is intermittent digital ischemia due to digital arterial spasm in absence of underlying disease |
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*What is secondary Raynaud's syndrome? |
Raynaud's phenomenon
Obstructive Raynaud's syndrome
Fixed arterial obstruction w/ normal vasoconstrictive responses of arterioles |
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**What is the most common cause of unilateral claudication in a young male? |
Popliteal artery entrapment syndrome (PAES) |
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*What are the symptoms of PAES? |
Symptomatic occlusion or claudication following running, not walking |
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*How can symptoms of PAES be elicited in the lab? |
Active plantar flexion or passive dorsiflexion of foot causing diminished pulses or altered waveforms |
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**What is claudication? |
Reproducible pain in muscles occurring during exercise whether origin is vascular or not |
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*What three areas are the most frequent sites of claudication? |
Buttocks, thighs, calves |
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*What levels of occlusive disease are indicated in true claudication? |
Aorto-iliac, ilio-femoral, femoro-popliteal |
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**A patient presenting w/ ischemic rest pain complains of |
Foot or forefoot pain at night when supine, relieved by standing or leg dependency |
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*Where does ischemic rest pain occur? |
Forefoot, heel, toes but not in calf |
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*When does ischemic rest pain occur? |
When the limb is not in dependent position, and the pt's blood pressure is decreased |
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**Ischemic ulcers are |
Very painful & commonly located over the tibia, over the dorsum of foot, &/or toes |
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*What are the 6 symptoms of acute arterial occlusion? |
Pain
Pallor (paleness)
Pulselessness
Paresthesia (Lack of sensation)
Paralysis
Polar (cold) |
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*Why is an acute arterial occlusion an emergency situation? |
The abrupt onset does not provide fro the development of collateral channels |
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**What are examples of LE arterial insufficiency skin changes? |
Changes in color, temperature, lesions; trophic changes (dryness, atrophy, shiny skin loss of hair growth over dorsum of toes & feet, thickening of toenails), capillary filling, & elevation/dependency changes |
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**When does cyanosis (blue color due to ischemia) occur? |
When there is a concentration of deoxygenated hemoglobin |
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*What does rubor suggest? |
Damaged, dilated vessels, or vessels dilated secondary to reactive hyperemia or infection |
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**Delayed return of capillary blush after pressure on pulp of digit is a sign of ? |
Decreased arterial perfusion/advanced ischemia |
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*The elevation of the extremity with impaired circulation produces |
Cadaveric pallor |
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*What is dependent rubor? |
Lowering the leg causes impaired skin to change from pallid to normal to red discoloration |
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**Why is it when the patient sits up, dependent rubor may occur? |
Marked increase of blood flow due to collaterals |
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**What extremity artery is NOT palpable/ |
Peroneal |
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*What is a thrill? |
A palpable bruit |
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**What does a palpable thrill signify? |
AVF
Post-stenotic turbulence
Patent hemodialysis access graft |
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*Why is there a thrill over a dialysis site? |
Increased flow volume |
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**What is the Allen test used for? |
To evaluate the patency of radial artery, ulnar artery, palmar arch |
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What is the limitations of the Allen test? |
Excessive wrist dorsiflexion or fingers forcibly extended may lead to false positive |
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*How is the Allen test performed? |
The radial artery is compressed, the hand is clenched then relaxed |
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*What size probe is used for non-invasive testing in both UE & LE? |
8 - 10 MHz |
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*What are some drawbacks to analog analysis? |
Signal easily affected by noise, less sensitive than spectral analysis, high velocities underestimated, low velocities overestimated, reverse component may be heard but not seen, uncompensated CHF may result in dampened waveforms, unable to discriminate stenosis from occlusion |
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**Since high velocities are underestimated, analog recordings ______ display amplitudes of all frequencies |
Do not |
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*The most widely used interpretive technique for analog Doppler waveforms is |
Qualitative approach or pattern recognition |
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**What are the three types of highly resistant signals? |
Triphasic
Biphasic
Monophasic |
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*What happens when a waveform goes from triphasic to biphasic? |
There is no forward flow in diastole |
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**Where might monophasic signals be obtained? |
Proximal or distal to obstruction |
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*What is autoregulation? |
The ability of most vascular beds to maintain a constant level of blood flow over wide range of perfusion pressures |
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*In autoregulation, the resistance vessels _____ in response to rise in blood pressure & _______ in response to fall in blood pressure |
Constrict
Dilate |
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**Flow to a warm (vasodilated) extremity will have _____ signals |
Continuous, steady |
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*Can a high resistance signal become monophasic proximal to stenosis? |
Yes, in order for there to be an increase in resistance |
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**How is it possible for a high resistance signal to become monophaisc proximal to stenosis? |
Vasodilation of distal vessels occur, reducing pulsatility, causing signals to have a low resistance (steady, continuous) flow quality |
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*An analog Doppler waveform of subclavian or axillary artery in normal individual would typically resemble? |
CFA or SFA waveform |
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*The AV shunts in the skin of fingertips cause flow patterns in the hand to be |
variable |
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**A dampened Doppler velocity waveform of subclavian artery isolates significant lesion |
Proximal to point of insonation |
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*Distal to aorto-iliac occlusion, the CFA signal is typically |
Low-pitched & monophasic
It is distinguished from pulsatile venou signal by having pt perform Valsalva |
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*What set of waveforms is most likely to obtained w/ CW Doppler when there is a long SFA occlusion? |
Triphasic waveforms at CFA & proximal SFA w/ monophasic waveforms in popliteal & tibial arteries |
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*Monophasic PTA waveforms, despite normal ABI in asymptomatic patient indicate that |
The high pass filter may be set too high, clipping frequencies near baseline |
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What is the Pulsatility index (PI)? |
The division of peak to peak frequency by mean frequency
(P1-P2)/mean
Peak systolic to peak end diastolic velocity divided by mean velocity
Peak systole-peak flow reversal/mean |
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*The PI is ______ beam-to-vessel angle |
independent of |
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*The values of the index ____ from central to peripheral arteries |
Increase
Ex. CFA > 5.5 & Pop = 8.0 |
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**What is the value of acceleration time? |
Helps to differentiate inflow (aorto-iliac) disease from outflow (SFA) disease |
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*There is _____ prolongation of acceleration time with disease distal to probe |
No |
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**What are some end-point detectors used to obtain pressure readings? |
Doppler instrument
Photocell (PPG)
APG
Strain-gauge plethysmography
Stethoscope
Pneumatic cuff |
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**How is the ABI calculated? |
Divide the ankle pressure by the higher of the two brachial pressures |
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**What is the ABI range for asymptomatic minimal arterial disease? |
.9 - 1.0 |
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**What is the range for claudication, moderate disease? |
0.5 - 0.9 |
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**What is the range for rest pain, severe arterial disease? |
< 0.5 |
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*An ABI , 0.5 may also suggest? |
Multi-level disease |
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**What are some limitations of Doppler segmental pressure study? |
Cannot discriminate between stenosis & occlusion, nor precisely locate the area of obstruction, it is difficult to distinguish CFA from EIA disease, & calcified vessels yield falsely elevated Doppler pressures |
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*What size cuffs are used on upper arms & legs? |
12 x 40 |
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*A _______ difference from one brachial pressure to the other suggests a > 50% diameter reduction of subclavian artery &/or vessel under cuff |
> 15 - 20 mmHg |
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**What suggests a brachial artery obstruction &/or obstruction in both radial & ulnar arteries, &/or obstruction in a single forearm artery? |
> 15-20 mmHg difference between upper arm & forearm |
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**The width of the cuffs on the legs should be at least _____ greater than the diameter of the limb |
20% |
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**Is there a disadvantage to using two high cuffs instead of one? |
Yes, artifically elevated pressures are obtained |
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**Why is one cuff more accurate? |
At 19 x 40 cm it is so wide that it satisfies the width-girth relationship |
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*In a non-diseased extremity, listening to popliteal artery w/ Doppler velocity detector & inflating thigh cuff, the observer is measuring pressure in which artery? |
Superficial femoral artery |
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*The cuffs should be inflated ______ beyond the last audible signal or higher than the highest brachial pressure |
no more than 20-30 mmHg |
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*What are two diseases that may falsely elevate Doppler pressures? |
Diabetes & ESRF |
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*Too narrow of a cuff may artifically _____ high thigh pressure |
elevate |
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**The high thigh pressure is at least _____ greater than the brachial pressure |
30 mmHg |
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*Which pressures should be at least the same as the brachial pressures? |
AK & BK |
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**If there is a drop in pressure of ______ between two consecutive levels, that is considered significant obstruction |
30 mmHg |
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*A horizontal difference of _____ suggests obstructive disease in the leg with lower level |
20-30 mmHg |
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**_______ is probably the best single vasodilator of resistance within skeletal muscle |
Exercise |
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*What is the purpose of exercise testing? |
To help differentiate between true claudication & pseudoclaudication, & to determine presence/absence of collaterals |
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**What are the effects of exercise? |
Vasodilatation causing decreased peripheral resistance & increasing blood flow |
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*What is the technique for using the treadmill? |
Pt walks at 10% elevation or less, 1.5 mph for up to 5 min or until symptoms are severe; duration of walking, progression of symptoms are documented, post-exercise ABIs are obtained at immediately then once every two minutes up to 20 min until pre-exercise ABIs are reached |
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**Normally, ABIs ____ post exercise |
Stay the same or slightly increase |
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**Ankle pressures that drop to low levels immediately & increase back to resting levels between 2 & 6 minutes suggest |
Single-level disease |
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**Why would a monophasic signal appear normally in an extremity artery after exercise? |
Exercise causes peripheral dilatation & reduced resistance w/ a continuous signal quality |
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*What is an alternative to exercise if the patient cannot walk, has pulmonary problems or poor cardiac status? |
Post-occlusive reactive hyperemia (PORH) |
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*Which one is preferable, treadmill or PORH? |
Treadmill because it produces physiologic stress that reproduces ischemic symptoms |
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*What is a contraindication for PORH? |
Bypass grafts & stents |
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*What is the technique for PORH? |
Thigh cuffs are inflated to suprasystolic pressures (20-30 mmHg higher) with pressure maintained for 3-5 minutes, & ankle pressures are recorded |
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*Little or no increase of blood flow velocity in response to PORH would most likely indicate? |
Significant obstructive disease |
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*What is the difference in immediate results between treadmill testing & PORH? |
Normal limbs do not show an ankle drop post treadmill, but they do PORH |
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**What is the normal ankle pressure transient decrease? |
17-34% |
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*Patients with single-level disease present with a ______ drop in ankle pressure |
34-50% |
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*A normal PORH velocity response is |
a > 100% increase in mean velocity |
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**________ is an electrical voltage that reverses its polarity (positive or negative voltages) at 60 times a second |
AC coupling |
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**Why is AC required for arterial studies? |
Relatively intense flow changes are required to produce a measurable signal |
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*Household receptacles deliver 120 volts of |
AC |
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**What are three capabilities of plethysmography? |
Can help differentiate between true arterial claudication & non-vascular claudication, help localize level of obstruction, & it can document the functional aspect of disease |
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**What are limitations of plethysmography? |
It cannot be specific to one vessel nor can it discriminate between major arteries & collaterals, cannot discriminate between stenosis & occlusion. Also, it is difficult to perform on obese patients |
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*Inability to center the stylus may be due to what? |
Incorrectly selected mode (AC vs DC) |
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*What is another name for volume pulse recording (VPR/PVR)? |
Air/displacement/volume plethysmography |
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**Momentary volume changes in the limb are converted into _____ within the cuff bladder due to arterial expansion in systole |
Pulsatile pressure changes |
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**A _______ converts pressure changes into an analog waveform |
Pressure transducer |
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**The waveform represents how much blood flow is moving via ____ pulsatile vessel |
every sized |
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*The usual cuff pressure in arterial volume recording is |
65 mmHg |
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**Qualitative criteria for a normal VPR & PPG waveform is |
sharp, swift systolic peak, rapid down stroke w/ a prominent reflected (dicrotic notched) wave halfway down |
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*What will often eliminate the dicrotic notch? |
Vasodilatation |
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*What is VPR artifact typically due to? |
Improper cuff application (too tight & can diminish/obliterate waveforms) |
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*PVR's demonstrate a lack of dicrotic notch in the recordings at the thigh, decreased pulses at the upper calf, & flat tracings at the ankle. The most likely interpretation of this study is |
mid ilio-femoral stenosis, severe SFA stenosis/occlusion, & severe infra popliteal disease |
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*The most often used application of PPG is for |
Evaluation of digits & penile pressures |
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*What can PPG test do? |
Differentiate fixed arterial obstruction from vasospasm |
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*How is the patient placed for finger evaluation? |
Sitting with arms resting on a pillow in patient's lap |
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*The width of the cuff should be at least ______ that of digit |
1.2 times |
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**What size cuff is used for the fingers? |
2 - 2.5 cm |
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*What size cuff is used for the great toe? |
2.5 - 3 cm |
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**How high is the cuff inflated? |
20-30 mmHg above the ankle pressure |
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*What is the paper speed? |
5 mm/s |
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*Where is peak systole seen? |
At first significant pulse |
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*What do the rapid fluctuations on plethysmography tracing represent? |
"Cyclic flow" |
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*What does the upstroke rise on a plethysmography tracing represent? |
Increase in blood volume secondary to obstruction from venous outflow |
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*Abnormal waveforms always reflect hemodynamically significant disease ____ to the level of tracing |
Proximal |
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*Reduced amplitude with no changes in the contour is likely to reflect insignificant disease, unless it is |
unilateral |
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**A mildly abnormal wave has an absent reflected wave (dicrotic notch), & the downslope is bowed away |
from the baseline |
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**Under what circumstance is there a fair (mildly abnormal) waveform quality but abnormal Doppler pressure? |
In the presence of collaterals there is a high amplitude signal but no dicrotic notch |
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**A moderately abnormal wave |
has a flattened systolic peak, upslope & downslope is more delayed, and reflected wave is absent reflecting hemodynamically significant disease |
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**A severely abnormal wave |
has a low amplitude or is absent |
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**Normally, the UE digits have finger/brachial indices of about |
0.8-0.9 |
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**Normal toe/ankle indices (TAIs) vary from _____ of the ankle pressure |
60-80% |
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*How do you document the presence/absence of intermittent digital ischemia in response to cold exposure? |
Perform the resting study, immerse the hands in ice cold water for three minutes, dry the hands, obtain waveforms & pressures immediately & five minutes later |
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**What is the difference between organic (obstructive/fixed) occlusive findings & functional (intermittent) obstructive findings? |
Organic disease has abnormal Doppler signals, systolic pressures, & PPG tracings. Functional disease has normal Doppler signals, etc but abnormal findings after cold stress test |
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**What is the difference between abnormal obstructive waveform quality & abnormal peaked waveform quality? |
Both have slow upstrokes, but after cold stimulation the peaked waveform of Raynaud's phenomenon has a sharp anacrotic notch, & the reflected wave is located high as a vasospastic process |
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*Patients with true vasospasm may have a contour that is normal in quality but decreased in |
amplitude |
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**If you suspect a 50% diameter reduction (75% area reduction), what do you obtain? |
Pre stenotic PSV, PSV within stenosis, post-stenotic signals |
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*If PSV increases by a 2:1 ratio in any artery, what does this mean? |
> or = 50% stenosis |
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*How common is UE aneurysm? |
not common |
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*______ aneurysms often are associated with embolization to digits |
Subclavian |
|
**What are two types of non-synthetic grafts? |
Reversed saphenous vein graft (RSVG), in situ GSV graft |
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**What are two types of synthetic grafts? |
Gore-Tex (PTFE), Dacron |
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*What must be done to the GSV prior to use as an in situ graft? |
Valves are broken up with a valvulatome & branches are ligated |
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*The UE vein most commonly used as a bypass in the leg is? |
Cephalic vein |
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*For a bypass graft to be successful, what is necessary |
Good inflow, good conduit, good outflow |
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**Why are anastomosis sites crucial? |
This is where aneurysms & stenosis occur |
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*The velocities measured in an RSVG are usually |
Higher proximally in the smaller diameter portion & lower distally |
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**What happens to flow velocity at the large venous end of an RSVG? |
The large end is anastomosed at the distal artery, and flow velocity is decreased |
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**Is PSV of 45 cm/s anbnormal in the large diameter segmet? |
Not necessarily |
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**What are other graft complications? |
CHF caused by increased venous return due to high pressure gradient, a steal syndrome in which distal arterial blood flow is reversed into venous system |
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**What are some abnormal findings in a vein bypass graft? |
A decrease of 30 cm/s in any graft segment, a change from triphasic to biphasic waveforms, a decrease in ABIs > 0.15, reduced PSVs in the smallest graft diameter to < 45 cm/s, AVF, valve cusp left intact |
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*What is retrograde flow in the native artery evident of? |
Distal anastomosis of an RSVG |
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**The stenotic & prestenotic PSVs are compared. What would suggest a 50% diameter reduction? |
A > 100% increase (2:1 ratio) and/or between 200 & 400 cm/s |
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**What would suggest a 75% diameter reduction? |
4:1 ratio &/or > 400 cm/s PSV |
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**What is Transcutaneous oximetry (TcpO2) used for? |
Wound healing, amputation level determination, skin graft viability, foot perfusion, healing of a stump |
|
*What is Tcp02? |
Reflects tissue oxygen tension & relies on balance between O2 supply & consumption |
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**What is normal pO2 in mmHg? |
60-80 mmHg |
|
*What is borderline pO2? |
30-40 mmHg & healing should still occur |
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*What is non-healing pO2? |
10-15 mmHg |
|
*The most effective lytic treatment for acute arterial thrombosis is |
Urokinase or streptokinase |
|
*What is angioplasty? |
Percutaneous transluminal angioplasty (PTLA, PTA) is used to dilate a precise region of focal plaque in a large vessel (illiac, femoral, popliteal, renal) |