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156 Cards in this Set

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explain why duplex u/s is useful?
-provides useful info about physiologic anatomy at the actual sites of stenosis
-imaging of the arteries is effective and accurate in identifying arterial disease in lower limbs and abdomen
-color ofers advantages to arterial evaluation
-2D would show cleen wals w/out atheroma
why is it important when evaluating a peripheral artery, to doppler at closely spaced intervals?
-high velocity jet and turbulence are damped out only after a distance of a few vessel diameters
-failure to documentall of the lesions along th evessel will severey underestimate the severity of the disease
what hare the indications for arterial reconstructive surgery?
gangrene
-non-healing ishemic ulcer
-isschemic rest pain
-immediate limb salvage(thromboembolism)
-less clear cut indications may be for patients that have relatively debilitating claudication effecting their daily routines
what are the most common sites of chronic obliterative atherosclerosis?
-infrarenal abdominal ao(most troublesome at the bifercation)
-iliac arteries
-obliterative disease below the inguinal ligament
-disease is usually segmental
explain type 1 of aortoilliac disease
-localized to distal AO, and common iliacs
-rarely produces limb thretening condictions due to adequeate colloaterals
-only 5-10% of patients are this type
-impotence occurs 30-50% in men with this type
-younger patients w/ low incidence of diabetes or hypertension
type 3 aortoilliac disease
-widespread disease(multisegmental)
-patients are more likely to have diabetes, hypertension, and associated atherosclerotic disease
-more likely to have advanced claudication resulting in ishemic rest pain and tissue nechrosis
-acounts for 65% of patients w/ aorto-illiac disease
plain endartectomy
-feasible w/ type 1 patients
-low infection rate, and has excellent results
-pt. must have disease just limited to at or just beyond the common iliac bifercation
-risk of neointimal hyperplasia
what are the contraindications of endartectomy in the lower extremity?
-possible aneurysmal degredation
-total occlusion in the Ao below the level of the renals
-Type 2 or 3 disease
explain the pros and cons of end to end vs. end to side for aortic grafts?
End to end:
-most recommended to to stability of hemodynamics
-better long term patency and less flow disruption
-placed directly into anatomic aortic bed which is most advantageous

End to Side:
-prosthetic end anastomosis to the side of the aorta instead of insitu
-desirable in certain anatomic patterns of disease, or done in order to avoid sacrafice of SMA or renal arteries
what happens to arterial ouflow post operatively w/ leg grafts?
arterial ouflow post operatively will be hyperemic, but over the course of about 2 wks, the flow should return to normal triphasic appearance
name and explain the diagnostic criteria for stenosis of a graft from normal to occlusion
normal=walls and lumen free of irregularity; no evidence of stenosis
1-19% diam reduction=minimal disease shows minor changes within lumen. Velocity ratio<2
50-74%=stenotic jet and post stenotic turbulence; usually due to valve leaflet or intimal hyperplasia; velocity ration2.5-3.5
75-99%=stenotic jet; velocity ratio>3.5; post stenotic turbulence; abnormal ABI
Occlusion=no flow; limb ishemia
-adjust color parameters or use color doppler to be sure
If a graft is abnormal, it may require revision, which may be what?
-patch
-angioplasty
-percutaneous transluminal angioplasty(PTA)
-replacement of graft
what is the standard for graft survalence
-intraoperative to 4 weeks discharge
-2-3 months intervals for 1st year
-6-12 months after that
Explain assessment for AV fistulas?
-difficult to confirm w/ visualization; indirect evidenc may be the only basis for diagnosis
Document:
-arterial flow @ the point of cannulation(assuming iatrogenic AV fistula)
-there may be turbulence @ the site of defect but no other flow abnormalities
-venous flow at the site and distal in the leg:
-pulsitile w/ increased velocities
-compare effected leg to unaffected leg.
-document connection btw artery and vein
what should be documented when scanning an aneurysm?
-size
-prox and sital extent
-sag measurments
-proximity to renal arteries
-check other sites for aneurysm
-presence of thrombus or dissection
-spectral doppler and color doppler to assess for stenosiss
-assess arterial flow prox and distal to aneurysm for flow abnormalities
what are the treatment options for patients who are not candidates for bypass grafting?
Non-operative care: limit disease progression
Surgical treatment:
-endartectomy(don't do frequently)
-bypass grafting
-extra-anatomic grafts
What are the classifications of bypass grafts?
-abdominal aortic grafts
-infrainguinal grafts
-extra-anatomic bypass grafts
what are the presenting symptoms w/ type 1 aorto-illiac disease?
-various degrees of claudication(usually involving the prox. musculature of the thick, hip or butt; one leg is more affected than the other)
-impotence in 30-50% of male patients
-youger patients w/ a low incidence of diabetes or hypertension
-can be treated w/ angioplasty
Explain infrainguinal bypassing?
-grafting for disease below the groin
-80-90% limb salvage rate
what are the indications for extra-anatomic bypass grafts?
-limited salvage
-intra-abdominal disease where abdominal approach is limited
How are grafts selected?
-most important criteria=proper size of graft; grafts that are too large for run off vessels cause:
-sluggish flow
-development of excessive pseudolaminar deposition
-may cause graft loss.
Pre-op assessment of the distal circulation is important
what is the surgical success rate of bypass grafts?
-85-95% graft patency at 5 years
-70-75% graft patency at 10 years
-perioperative mortality rates under 3%(higher w/ multilevel disease)
-long term survival=poor(25-30% die within 5 years due to MI)
What are the early complications of bypass grafts?(<30 days)
-technical
-hypercoagulable state
-inadequate flow
-hemorrage
-limb ishemia(acute thrombosis of reconstruction distal thromboembolic complications-perfusion should increase in 4-6 hours)
what are the complications w/ bypass grafts 1-6 months post op, 6-24 months, >24 months
1-6 months-residual lesion(ocurs in 3-5% of grafts and accounts for 1/4 of graft failures)
6-24 months-myointimal hyperplasia(acounts for 3/4 of graft failures)
>24 months=progression of atherosclerosis
Explain thrombus as a complication of bypass grafting?
can happen when they clamp
-atheromatous debri, or thrombus dislodge after clamping
-trash foot occurs as a result
explain trash foot?
-acute occlusion or thrombus that affects blood flow int he toes or feet
-common frusteration to the vascular surgeon
-assessment of the distal arteries and popiteal artery is NB
-occurs as a symptom of thrombus post bypass graft
what are some complications that can occur immediately post op(usually w/ patients that have underlying medical conditions)
-renal failure
-intestinal ishemia
-spinal cord ishemia
-ureteral injury
why is there such high survallence on bypass grafts post op?
-20-30% stenosis rate within 1 year
-if graft occludes, 20-50% patency rate after thrombectomy
-60% of graft stenoses are asymptomatic due to limited ambulation of patients(doesn't allow them to pick up clinical symptoms)
what are the goals w/ bypass graft assessment?
-identify correctable lesions before graft thrombosis
-determine baseline hemodynamics post revascularization
-provide objective clinical info to aid in decision making regarding treatment alternatives
what are you looking for/what images are you taking in longitudinal and transverse of bypass grafts?
longitundinal-velocity spectral waveforms
transverse:
-change in diameter
-intimal hyperplasia
-valve leaflets and features
-wall thickening
-directional changes
what should you look for w/ 2D and color of the walls and leaflets of a bypass graft?
walls:
-contour
-thickness
-kinks/twists
-anastomosis sites

valves:
-description
-location
-desciption of valve sinus
-mobility of the valves
explain the overall dysfunction of graft function?
-stenosis within 3 months; spontaneous regression seen in <one third of cases; most progress and eventually become occlused
-40% remain stable or progress
What are some things to consider when assessing bypass grafts?
-normal variations in flow patterns
-naturally occuring diameter changes in the early post-op period(hyperemia)
-waveform is affected by the receoding site, length of time post op and outlow resistance
What are some factors that need to be corrilated with the diagnostic criteria to determine stenossi?
-waveform configeration
-status of ABI
-B-mode image
-Max graft PSV from smallest normal segment of graft
-Serial exam changes(>0.15 decrease in ABI; >30cm/sec decreased in graft PSV)
what are some serial exam changes to look for with bypass grafts?
>0.15decrease in ABI
>30cm/sec decrease in graft PSV
what is the criteria for a failing illiac system?
-ABI or toe pressure decrease >o.15 compared to last study
-development of an abrnomal CFA doppler waveform
-Hemodynamically failing iliac angioplasty:
PSV>300cm;sec
VR>2
What is the threshold for graft revision?
PSV>300cm/sec
VR>3.5
Low velocity <40-45cm/sec
Decreased ABI
what is the thrombotic threshold velocity?
PSV <45 or >30cm/sec diff from prev./ exam
PSV>200 may be indicitive of graft failure


Correct:

what are the late complications of graft failure?
what are the late complications of graft failure?
occlusion
anastamotic false aneurysm
impotence
imfections
aortoenteric fistula
explain Graft occlusion
5-10% chance 5 yrs post op
15-30% chance 10 years post op
most common late complication
Explain graft occlusion for Aortofemoral grafts:
-occlusion will affect one limb
-resulting ishemia more severe than prior
-reoperation urgent for limb salvage
Explain anatomotic false anurysms, and their contributing factors?
-second most common complication
-1-5%
-most common at the femoral anastamosisContributing factors:
-degenerative changes within arterial wal(dehiscence of suture line)
-excessive tension on anastamosis due to improper graft length
-poor suture technique
-thin walled artery
explain infection as a late complication of bypass grafts? What are the contributing factors?
-worst complication pt. can get
-high morbidity and mortality
-<1%

Contributing factors:
-multiple vascular procedures
-presence of hematoma, seroma, lymph leakage at groin
-emergency operation
what should you assess with arterial steel?
-perfusion distally
-obtain PVR's or PPG
-obtain digital pressures
-if possible, temorarily occlude fistula while obtaining PVR/PPG waveforms
what do you look for post operatively for AVF's?
-Graft thrombus/stenosis
-flow volume
-arterial steel
-venous outflow
-peri-graft mass
-graft/fistula maturity(usually takes up to 4-6 wks)
-up to 40% of initial failure
-bridge grafts(PTFE) are most common procedure, 2: 1 to fistulas
explain PTFE loop grafts
-distal branchial artery to cephalic, median cubital, or basilic veins
-proximal brachial artery to axial vein
-lower extremity: SMA to saphenous vein
what are the indications for pre-op assessment?
-patients with a history of vein stripping
-previous DVT
-previous harvesting or bypass surgery
explain the basic conscept of hemodialysis?
-Central circulation is accessed-AVF, Graft, and central venous catheter
-blood cleansed by diffusion across a semi-permeable membrane
-2 15G needles placed into AVF or graft
-more distal(caudal) needle carries blood from the patient to the dialyzer
-second, mor proximal needle returns blood to patients circulation
what is the most common preoblem w/ dialysis grafts? explain it?
-venous anastamosis site or outflow bein becomees stenotic and thrombus formes due to increased arterial pressure.
-Stenosis in teh venous side of the graft happens in more than 80% of cases
-can produce endothelial damage or intimal hyperplasia
what is considered graft thretening lession?
propensity to:
-progress in severity
-reduce graft flow
-form surface thrombus
what are some exam indications for dialysis patients?
-pre-op assessment
-elevated pressures during dialysis
-puncture problems
-peri-graft fluid or mass
-distal limb ischemia
-poor dialysis
what are the purposes of intraoperative sonography?
-focal regions of abnormal flow
-presence of intimal flaps
-stricures
-early thrombus deposition
-perforating veins
-reassure surgeon
what is the protocol for surveillence of PTA's?
-obtain post-op history
-perform a pulse evaluation
-measure ABI
-color doppler
-characterize hamodynamics of graft flow
explain venous hypertension with dialysis grafts?
-too much blood in the hand; have to go and ligate vessels
forarm loop graft with venous stenosis
-retrograde venous flow
-patient w/ hand swelling and venous stasis
What are the criteria for graft flow volumes?
<250=poor dialysis pending graft failure
300-1000(ml/min)-normal
>1200-possible CHF(has to do w/ venous return to the heart)
what is ultrasound useful for in post-operative assessment?
-determining graft maturity
-If AVF maturity in doubt, serves as a triage function
-evaluates multiple anastomic features of the AVF
with arterrial evaluation for dialysis, what is considered normal?
<20mmHg btw brachials
arterial lumen diamter>2mm(outer to outer)
absence of radial artery stenosis
-patent palmar arch
what is the u/s purpose of assessing endografts?
aids in assessment of complications:
-endoleak
-limb dysfunction
-stenosis
-enlarging aneurysmal size
-other anatomical or hemodynamic impariment
what are the types of dialysis grafts placed in the upper arm, and rank them from most common to least?
-brachial artery to axillary artery(most common)
-brachial artery to antecubital vein(next)
-radial artery to cephalic vein(bresica-cimino graft)-least common
what are some things that can cause flow disturbances with dialysis grafts/
-venous thrombus
-kinking
-extrinsic compression
what is the threshold for graft revision?
-PSV>300cm/sec
-VR>3.5
-Low velociy<40-45cm/sec
-decreased ABI
what are the complications associated with dialysis access grafts/fistulas?
-thrombosis/occlusion/stenosis
-infection; mostly synthetic grafts(2puncture sites)
-arterial steal-digital ischemia
-distal venous hypertension
-aneruryms, pseudoaneurysms
-elevated rt. side heart pressure due to excessive graft flow
venous catheters
usesd for temporary ccess because grafts and fistulas take awhile to mature
-inserted into vein in neck, chest, or leg near groin
-have 2 chambers to allow two-way flow of blood
-look for thrombus
what is done to reliably identify failing PTA?
-serial clinical evaluations-mesurement of limb pressures
-doppler waveform analysis at 6 month intervls
how is graft flow volume calculated? what is the formula?
-Q=graft area x TAV x 60
-Q=area x avg max vel. x 60sec
-select clean site midgraft
-in trx, obtain lumen diamete r(turn off color to measure diameter)
-in longitudinal, expand sample gate to diameter of vessel
-obtain several spectral wavefomrs and calculate time average velocity.
what are some signs of possible access failure twith dialysis grafts?
-difficult cannulation, or thrombus aspiration
-elevated venous pressure>200Hg
-access recirculation of 12% or greater
-unexplained area reduction
-shunt collapse
what is the pre-operative assessment procedure?
-evaluat arterial inflow
-evaluate entire venous outflow
-assess vessel size
-assess palmar patency
What is the normal flow pattern of grafts and fistulas for dialysis?
PSV=100-400cm/sec
EDV=60-200cm/sec
high flow
low resistance
disorganized flow w/ spectral broadening due to larger diameter of vessel
explain how pseudoaneurysms can effect dialysis grafts?
-<1cm=no problem
>1cm=problematic
graft disentegration, anastomotic failure
Explain PTA surveillance?
aka peripheral trasluminal angioplasty
Indirect evaluation:
-Clinical status
-ABI's
-Toe pressure in diabetics
graft stenosis criteria for dialysis grafts?
-MIld stenosis: velocity increase, but <50% or preceding segment
-moderate stenosis=50-99%velocity increase from preceding segment
-severe stenosis:
-velocity increase>100% of preceding segment with a 50% drop distally(>50% diam. reduction)
-PSV>300cm/sec
explain how to assess endografts w/ 2D, color and spectral?
2D;
-assess entire endograft
-assess attachment sites
-assess entire residual aneurysm sac

Color/Spectral:
-identify and confirm endoleaks
-identify source of endoleak
-limb dysfunction
-graft patency
-outlfow vessels
explain arterial grafts
-radial or mammary arteries
-reduced incidence of basospasm
-improved longevity
-mapping proceduce-similar to vein mapping
-radial artery study for palmar arch patency
if the arterial flow is >400cm/sec, what is the probable outcome of the dialysis graft?
-75% diameter reduction
-due to increased vnous return from the dialysis graft, CHF can develop
explain type 4 endoleak
graft porosity:
-flow through graft material
-"porosity blush"-when blood seeps through the walls
-don't see distinct walls(shaggy look)
what should you focus on when scanning a aortic endovascular graft stent?
-patency
-presenc of perigraft leaks
-enlarging aneurysm size'
-other complications
Other than endoleaks, what other complications can occur with aortic endovascular stent grafts?
-graft limb dysfunction
-intimal tears or dissections
-pseudoaneurysm
-AV fistulas
-Ishemia/Embolization
-Graft redundancy
-wire cracks/fractures
what are the endograft characteristics of support, design, and configurations?
Support:
-complete externally supported
-supported at attachment or fixation sites

Design:
-modular design
-single body construction

Configurations:
-bifurcated tube
-aorto-uni-illiac configuration
what are the categories of endoleaks?
look at diagram in power point:
I-attachment leak
2-branch leak
3-device related
4-graft porosity
5-site undefined
why must patients that have had PTA take medications?
-make platelets less active
-combination of aspirin and plavix
-once the stent is completely covered by natural material, plavix can be discontinued
how is endoleak diagnosed? explain
-primarily by CT
-Color duplex sonography is used because it's inexpensive, reproducable, and compliments CT scan
Explain endograft limb dysfunction?
-most common complication other than endoleaks
-twisting or kinking
-stenosis/crimping
-incomplete deployment
-thrombosis/occlusion
-migration
explain some contraindications for renal artery stentting?
-relative, and not absolute
-risk to benefit must be considered:
-atheroembolic disease(shaggy ao)
-renal artery aneurysms
explain type 3 endoleak?
device related:
-flow through the body of the graft
-graft to graft connections(w/ multilib graft)
-graft defect or hole
what are the indications for renal stenting?
->70% stenosis of RA and poorly controlled HTN
-aortoostial lesions
-restenosis lesions
-suboptimal balloon angioplasty
-renal failure and assoc. renal artery stenosis
-hemdialysis patients w/ stenosis
explain the aortic endovascular stent graft
-introduced in the 90's
-follow carefully w/ u/s
-alternative to surgical repair of abdominal aortic aneurysm
-placed transluminally through small femoral incisions and deployed remotely
explain endoleaks with aorto endovascular stent grafts?
-presence of flow within residual aneurysm sac after endovascular graft placement
-identified w/ all devices
-occurs in 44% of all repairs
-provide potential for aneurysm expansion
-increase risk of aneurysm rupture
-no way to predict endoleak or potential rupture
what are the types of renal stents commonly used?
-pure metal alloys(wallstent, pamaz)
-elastic
-plastic
-thermoelastic-nitinol
If there is no attenuation when either CCA is compressed with supraorbital doppler, what does this mean?
there is collateralization via the vertebrobasilar arteries
Explain how carotid compressions are done with OPG-G testing?
-carotid artery is compressed for 3-5 seconds while the OPG maintains an intraocular pressure of 60mmHg
-If pulsations are noted during this, then the carotid artery is compressed for < or equal to 15 seconds while the OPG decreases the intraocular pressure from 110mmHg to the level at which the pulsations reappear.
-carotid compressions should be released gradually to prevent the sudden return of blood flow
diff. btw penetrating arteries supplying the brain, and diffuse superficial arteries
-Penetrating arteries; neuronal function and nutrient supply for CNS
-Diffuse superficial arteries: collateral circulation routes including circle of willis and major arterial trunks
What are the techinical errors that can be made w/ periorbital doppler?
-ECA branches vs. opthalmic artery branches
-excessive transducer pressure
-inapropriate compression technique
what are the different types of intracranial to extracranial anastamosis?
-connections via the opthalmic and orbital arteries, the meningophophyseal branches, and the carotid-typanic branches
-connections via the occipital branch of the ECA and the atlantic portion of the vertebral artery
-ECA's connections across midline
-Deep cervical and ascending cevical branches of the subclavian artery to the lower vertebral artery, atlantic portion of the vertebral artery, and the occipital branch of the ECA
Explain the anatomy of the ECA?
-3mm
-anterior and medial to ICA
-gives off branches right away
-has eight branches that supply the face, neck, thyroid, ear, scalp and dura maater
what are the major collateral pathways via the circle of willis?
-ECA to ICA via the opthalmic artery
-Crossover collateral via the ACA
-post. to ant. collateral via the PCA
What is the technique for supraorbital PPG?
-obtain signal from PPG
-optimally adjust pulse amplitude(25-30mmheight and paper speed at 5mm/sec)
-compress temporal arteries bilaterally(for 5 beats)
-depress foot switch at the same time of compression
-compress supraorbital
-compress both facial art.
-compress ipsilateral and contralateral CCA's(optional)
explain the anatomy of the common carotid artery?
-5-6mm in size
-rt CCA originates from the brachio-cephalic artery
-lt. CCA originates from the aortic arch
-bifercates into internal and external carotid artery
what are the eight branches of the ECA?
remember*A PISTOLS:
Ascending pharyngeal
Post. Auricle
Internal Maxillary
Superior thyroidal
Transverse faceial
Occipital
Linguial
Superficial temporal
What are the side effects that occur with OPG-G testing?
-subjunctival edema(redness and tearing-usually disappears within 30 minutes)
-severe redness of the sclera
-pt. should not rub eyes for a while
how is the OPG-G test done?
-patient supine
-bilateral brachial pressures taken(if BP<140, 300mmHg may be used; If BP>140mmHg, 500mmHg may be needed to obliterate flow)
-local anesthetic applied to eyes
-eye cups placed on lateral sclera(white of the eyes)
-vacuum applied to cups deforming the shape of the globe, and increasing intraocular pressure
-strip chart recordings are made as pressure increases to obliterate arterial flow-patient may experience temporary loss of vision
-as vacuum is released, pulse returns when the opthalmic arterial pressure exceeds the introcular pressure
-pressure in the opthalmic artery reflects the pressure n the distal ICA
What could cause a false negative or false positive with supraorbital PPG?
False negatives:
-improper ECA branch compression
-ipsilateral ICA and ECA obstruction

False positives:
-vasoconstriction
-anomolous circulation
-improper compression of ECA
what are the frequently seen symtoms of posterior cerebral artery stroke?
dyslexia and coma
name and explain the two systems that the brains blood supply is divided into?
-Anterior circulatory system: made up of carotid arteries and their branches
-Posterior circulatory system:made up of vertebrobasilar arteries and their branches
If siginificant stenosis is noted with Supraorbital PPG, how will the effect the temporal artery, or infraorbital or facial artery?
-W/ temporal artery compression, theer is attenuation of pulse amplitude by >33%
-w/ infraorbital or facial artery compression, there is reduction or >15% or pre-compression amplitude
what can cause false negatives with OPG testing?
-bilateral carotid artery disease
-stenosis<50%
-50-70% stenosis produces variable test results
what are the branches of the opthalmic artery? What do they supply
-central retial artery-supplies the eye
-suptraorbital artery-courses ant. and sup. till it reaches the globe, then joins the ECA via the superficial temporal artery
-frontal artery-exits orbit medially to supply midportion of the forhead; joins ECA via superficial temporal
-nasal artery/angular artery -branches off the fronatl artery to supply the nose. courses down lateral border of the nose. Joins ECA via the facial artery
what portions is the ICA divided into?
-Cervical
-petrois
-cavernous(siphon)-s-shaped
-supraclinoid
what does the carotid bulb do?
-the enlarged portion of the distal CCA(can be part of the proximal internal carotid artery)
-has baroreceptors that sense and regulate blood pressure
name and explain the arteries that the circle of willis is made up of?
-Anterior cerebral artery-carries 20-30% of the blood to the brain
-middle cerebral artery-carries 70-80% of blood to the brain
-post cerebral artery
-basilar artery-formed by vert. arteries and supplies blood to posterior structures
-distal ICA
-ant. communicating artery
-post communicating artery
explain how the test is done for palmar arch patency?
-basic upper arm study including digital pressures to r/o underlying stenosis
-PPG applied to thumb and 5th finger
-baseline arterial waveforms done
-compression of radial and ulnar arteries are done(both are compressed to ensure compression of the radial artery)
-record flatline waveform
-release ulnar artery, but continue pressing radial artery
-record waveform after release
-procedure may be repeated w/ ulnar artery compression
what is the function of duplex u/s in radial artery assessment?
r/o stenosis or incomplete palmar arch in the hand
what are the contraindications for using the radial artery for CABG
what are the contraindications for using the radial artery for CABG
Explain artery grafts?
-often the graft of choice over veins due to the ability to anastomose the artery to the native vessels and better longevity
explain the procedure for radial artery duplex imaging
-identify orign at the brachial artery
-measure diameter
-scan the course of the artery and measure distally
-average=2.8-men; 2.4mm=women
-make sure diameter is at least 2mm, but preferably >2.5-3mm
-not the course and any deviations from normal
Explain the course of the cephalic vein?
-begins along radial aspect of the hand
-communicates with basilic vein in the antecubital fossa via the medial cubital vein
-asc. laterall and empties into the axillary vein
what are the baseline PVR parameters for the resting digit study?
-digital BP should be within 20mmHg of the braqchial pressure
-digital/brachial ratio>0.8
-waveform should demonstrate upstroke time<0.2 seconds, and dicrotic notch
What is the purpose of radial artery harvesting? what are the advatages of using it over the saphenous vein?
-gaining popularity for CABG or some plastic surgeries
-usually taken from the non-dominent arm

ADVANTAGES(over saphenous):
-appropriate diameter
-thicker wall, less intimal hyperplasia
-availability
explain the course of the LSV, and its valves
aka short saphenous, small saphenous, or external saphenous
-distal end is post to lat. malleolus
-ascends in the subutaneous tissue of the calf btw the heads of the gastrochnemius muscles
-terminates in popiteal vein
-contains 7-13 valves which are more closely spaced than the GSV
Explain how visual inspection and venography are useful for vein mapping?
Visial inspection-cannot reveal diameter of vessel or duplications
Venography:
-can determine patency, location of tributaries, diameter, and double systems
-cannot map vessel on skin
-painful-risk of dye-induced phlebitis
explain the course of the basilic vein
-ulnar side of the wrist
-travels medially to join the brachial vein at the mid to upper 1/3 of the arm
explain how to mark the GSV a vein?
explain how to mark the GSV a vein?
-marks should be made every 2 cm
-vein should be centered in the middle of the u/s screen
-mark skin w/ straw, use a washcloth to wipe off gel, then mark the skin w/ an undelible marker
-dry the leg completely when finished, and connect the dots
-if a section is<2mm, it should be represented by a dotted line
-if a dual system is seen, the larger one should be a solid line, and the smaller one should be a dotted line
what are the phases for harvesting veins for CABG?
-determining suitability of vein
-mapping the vein
what should you look for when tracking the GSV?
-Ant. lateral vein-upper thigh
-posteromedial vein-mid thigh
-post. arch vein-below the knee
cutpoint
-point on the graph where above the test is considered abnormal, and below is considered normal
-cutpoint can be changed by changing criteria for what constitutes a positive test
-changing the cutpoint alters the sensitivity and specificty of a test
explain transient caviation
-bubble implode
-high requencies and large intensities are required to preoduce this effect(i.e.100w/cm2 at 1 MH
What does the ROC curve stand for?
receiver operating characteristic curve:
-graph that plots true positive rate against false positive rate for diff. possible cutpoints of a diagnostic test
-shows relationship btw sensitivity and specificity
how do you calculate the likelihood ratio for positive?
sensitivity/1-specificity
What is max heat related to?
SPTA:Descripter used in the AIUM statement on mammalian bioeffects
SPTA=SP/SA
For CW u/s, what intensities are equal?
SATP=SPTP
SATA=SPTA
describe stable caviation
-bubbles grow and fluctuate which can produce sheer stress, and micro-streaming
-doesn't occur in clinical practice because 2 or 3 ms pulses are required for bubbles to grow
-peak pressures >10megapascals or 3300w/cm2 can induce caviation
Likelihood ratio
-ratio that demonstrates the likelihood of disease as determined by the test
what are the main determinants that control exposure in u/s? how can exposure be reduced?
power, intensity, and time
-exposure can be reduced by keeping power output low, raise gain to keep power low, and decrease exam time
what (on a ROC curve), gives teh likelihood ratio for the value of the test?
the slow of the tangent line at a cutpoint gives the likelihood ratio fr that value of the test
When is intensity the highest? When is acoustic power the highest? lowest?
highest intensity=pulsed doppler
highest acoustic power=color
lowest acoust power=m-mode because PRF is only 500/s
How can you impliment the ALARA priniciple?
-keep output, intensit or power, and gain to the minimum level necessary by chosing the appropriate application of u/s equipment
-don't surpass FDA recomended intensities
-choose the most appropriate mode(b-mode, m-mode, or doppler)
-chose the most appropriate trx frequency, focal zone, focal range, and doppler sample volume size
-keep exposure time to a minimum by utilizing color when available
-performing only required u/s scans
formula for prevalence
true positives + false negatives/all people
Both the deep superior epigastric artery and the deep inferior epigastric artery branch off a different artery. Name the arteries.
Both of these arteries contribute blood to what muscle?
-The superior epigastric artery is a terminal branch of the internal mammary artery.
-It branches smaller, anastomosing with branches of the deep inferior epigastric artery which arises off the external iliac artery.
-This anastomatic region is known as the “watershed area”.
-Both of these arteries, including their perforators, contribute to the blood supply of the rectus abdominus muscle, a long strap muscle, vertically oriented, lying one to either side of midline.
What is the dialysis graft stenosis criteria according to diagle?
Mild=Velocity increase, but<50% increase in velocity compared to the preceding segment
MOderate=velocity increase btw 50-99% of preceding segment
Severe=velocity increase>100% of preceding segment w/ a 50% velocity drop distally; PSV>300cm/sec
What is the main reason the superior epigastric artery and deep inferior epigastric artery are mapped prior to surgery?
-the surgeon uses the best arterially supplied muscle section for what is called the TRAM flap, used for autogeneous breast reconstruction after a mastectomy.
what are the complicatios for bypass grafts in the first 30 days, 1-6 months, 6-24 months, and >24 months
-<30 days: Technical, hypercoagulable states, inadequate flow
-1-6mo: residual lesion
-6-24mo: myointimal hyperplasia
->24 months: progression of atherosclerosis
Describe two complications that can occur with placement of a hemodialysis access graft.
1. Increased venous return to the heart, resulting in congestive heart failure (CHF). The closer to the heart the access graft is (e.g. arm), the higher the likelihood is of this happening.
2. “steal syndrome”. With the “dialysis access” in the forearm (e.g. Brescia-Cimino), a “steal syndrome” would cause pain on exertion, and pallor and coolness of the hand due to its distal proximity to the shunt.
A patient presents to your diagnostic facility to evaluate an asymptomatic right carotid bruit. The carotid duplex examination documents a complete occlusion of the left internal carotid artery. Name three collateral pathways that could be providing blood flow to the left hemisphere preventing a neurological deficit.
-Cross-over collateralization:
-External-to-internal collateralization:
-Posterior-to-anterior collateralization:
what is the criteria for failing iliac system(threshold for graft revision)
-ABI or to pressure decrease by >0.15 from previous
-abnormal CFA doppler wavefom
-PSV>300cm/sec; EDV 20cm/sec
-VR>2
-Overall velocity(<40-45cm/sec)
Give two reasons why intraoperative monitoring is useful during insertion of a vein graft.
 check the patency of the anastomatic sites
 evaluate suspicious stenotic or turbulent flow areas (such as valve cusp sites or suspected branch sites).
describe stents, and how they work?
 designed to maintain the intraluminal structure and patency of the artery
 acts as a type of “scaffold”
 similar techniques as in angiography utilized to insert the introducer sheath
What are the most common sites of stenosis in a hemodialysis access graft?
Why are these sites so vulnerable to stenosis?
-The venous anastomosis and the outflow vein are the most common sites of stenosis in a hemodialysis access graft.
-vulnerable due to the increased arterial pressure into the outflow vein, which can produce endothelial damage. In addition, intimal hyperplasia can also occur, resulting in stenosis.
what is the diagnostic criteria for graft stenosis?
1-19%-minimal disease w/ minor changes within lumen walls; PSV <150cm/sec, VR<2

20-50% diam reduction: PSV <150cm/sec; EDV<100cm/sec; VR 1.5-2.5; mod spectral broadening

50-74%= PSV>140cm/sec; EDV<100cm/sec; VR 2.5-3.5cm/sec; spectral broadening throughout cardiac cycle w/ turbulence

75-99%=PSV>300cm/sec; EDV>100cm/sec; VR >3.5; ABI >0.15 change from serial exam; spectral broadening throughout cardiac cycle and turbulenc
what is the suggested criteria for carotid stent stenosis?
50-75%=PSV>150-200cm/sec; ICA/CCA ratio 2:4
70-80% stenosis: PSV>300cm/sec; ICA/CCA ratio >4
>80% stenosis: PSV 320-340cm/sec
EDV 120-140cm/sec
Besides the epigastric arteries, preoperative arterial mapping is also done for two other arteries. Name the arteries and how they are utilized.
1. Internal mammary artery (internal thoracic artery):
 Utilized as a recipient site for “free flaps” (which are smaller flaps) in breast reconstruction
 A second important use is as a graft to the left anterior descending (LAD) coronary artery.
2. Radial artery:
 Duplex imaging is used to determine artery’s suitability for use as a graft for coronary artery bypass.
When utilizing duplex scanning for assessment of a dialysis access graft, what are the key areas that must be evaluated?
 Inflow artery
 Arterial anastomosis
 Body of the graft
 Venous anastomosis
 Outflow vein
what questions should we, as sonographers, ask ourselves when performing serial scans on a bypass graft patient?
-Has flow in any graft segment decreased by at least 30 cm/sec?
-Has the Doppler signal quality changed from triphasic to biphasic?
-Has the ABI decreased by more than 0.15?
-Has the Doppler PSV decreased to < 45 cm/sec in the smallest diameter
Name at least 2 surgical uses for a suitable vein
-as a bypass graft for extremity or coronary
-for use in dialysis access.
what do successful bypass grafts require?
 good inflow
 adequate conduit
 good outflow
Explain external to internal collateralization
-Retrograde flow is seen in the ophthalmic artery.
-The majority of flow results from external-to-internal carotid collateralization through distal branches of the superficial temporal artery that anastomose with distal branches of the ophthalmic artery.
-Intracranial flow is via the ipsilateral ophthalmic artery.
Describe “blue toe syndrome” and what causes it.
-when embolic material moves distally until it becomes lodged in a small caliber vessel such as a digital artery.
-The resulting lack of flow causes cyanosis (bluish discoloration related to the presence of deoxygenated hemoglobin in the blood).
-can be a reversible condition.

This syndrome may be caused by any of the following:
 aneurysmal disease
 arteritis (inflammation of the artery wall that can lead to thrombosis)
 ulcerated and/or atherosclerotic lesions
 some angiographic procedures
What is the stenosis criteria for dialysis fistulas?
PSV>250-400cm/sec=at least >50% stenosis
Ratio>3:1 PSV@ stenotic site compared to 2cm cranially