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96 Cards in this Set
- Front
- Back
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name the advantages and disadvantages of using arteriography, indirect methods, single plane arteriograms, biplane arteriograms, and ultrasound for evaluating lower extremities?
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-Arteriography-gold standard; useful for anatomy; invasive, and doesn't provide info about physiologic events
-indirect methods-sidely used and provides important physiologic info, but is limited in anatomic info. -single plane arteriograms-may miss plaque on post wall -biplanar arteriograms-better at visiualizing post wall, but increased accuracy of diagnosis has not been proved. -ultrasound-useful in may aspects, esp for predicting outcome of treatment options; provides useful baseline. |
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explain why duplex u/s is useful?
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-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 |
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what scan heads are used for average sized patients for abdominal doppler, small abdominal doppler patients, leg doppler?
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average pt abdominal=3mHz
small pt. abdominal=5mHz distal, superficial arteries in the legs=5, 7.5, 10mHz |
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why is it important when evaluating a peripheral artery, to doppler at closely spaced intervals?
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-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 |
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how are occluded segments measured?
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from the prox. point of occlusion to the distal site where recanalization occurs
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T/F like carotid disease, hemodynamically signficant stenosis may not produce symptoms of ishemia in the lower extremities?
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false
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where does a complete lower arterial scan begin?
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at the prox potion of the abdominal aorta
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explain the interogation of the Internal iliac artery for lower extremity testing purposes?
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-velocity measurement can be obtaned at the origin, but it doesn't have to be followed unless indicated.
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what are the sites where waveforms should be obtained for duplex scanning of the lower extremity arteries?
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-Prox and dist. CFA
-Prox PFA -Prox, mid nd dist. SFA -Prox and dis. Pop a. -Prox and distal PTA, ATA, and peroneal artery -areas of aliasing or plaque |
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how does the peak velocity change from the illiac to popiteal?
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-decrease in PSV from illiac to pop.
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what are the 3 phases of the triphasic waveform?
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-high velocity forward flow in systole
-breif reversal in early diastole -low velocity forward flow in late diastole |
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what is the reversed flow component in a triphasic waveform due to? when is it lost
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-result of high peripheral reistance in the lower extremity
-lost when there is reactive hyperemia or limp warming which decreases the resistance -lost distal to severe occlusive lesions |
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T/F you can often see arterial grafts because a patient had intermittent claudication?
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false-rarely done for intermittent claudication
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what hare the indications for arterial reconstructive surgery?
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-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 |
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what are the most common sites of chronic obliterative atherosclerosis?
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-infrarenal abdominal ao(most troublesome at the bifercation)
-iliac arteries -obliterative disease below the inguinal ligament -disease is usually segmental |
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explain type 1 of aortoilliac disease
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AORTO-ILLIAC 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 |
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explain type 2 of aortoilliac disease
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-where the disease is confined to the abdomen and accounts for 25% of patents
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type 3 aortoilliac disease
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-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 |
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what are some clear cut indications ofr arterial reconstruction?
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-tissue nechrosis(ishemic ulcers and gangrene)
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T/F there is no known cure for occlusive disease?
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true
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what are the surgical treatments for occulsive disease?
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-endartectomy
-bypass -grafting -entraanatomic grafts |
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Explain endartectomy
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-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 |
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what are the contraindications of endartectomy in the lower extremity?
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-possible aneurysmal degredation
-total occlusion in the Ao below the level of the renals -Type 2 or 3 disease |
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explain the pros and cons of end to end vs. end to side for aortic grafts?
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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 |
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why may inflow arterial reconstruction not be done in patients w/ multilevel disease?
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-often insufficient to releive symptoms
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explain myointimal hyperplasia?
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-thickened, echogenic walls that develop over time
-most common cause of graft failure<5 yrs -may cause stenosis |
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what is the most common cause of graft complication? second?
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first=myointimal hyperplasia
second=false aneurysm |
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which artery is particularly important to assess preoperatively for grafts of the lower limbs?
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the profunda artery because it's patency is very important for graft success.
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what do outflow and runoff assessment determine?
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the overall sucess of the graft
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what happens to arterial ouflow post operatively w/ leg grafts?
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arterial ouflow post operatively will be hyperemic, but over the course of about 2 wks, the flow should return to normal triphasic appearance
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what sites should be interogated post operative of a leg graft?(from sup to inf)
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-inflow
-prox anastamosis -post anastamosis -prox, mid, and dist graft -pre anast -distal anastamosis -outflow |
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name and explain the diagnostic criteria for stenosis of a graft from normal to occlusion
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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 |
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what is the formula for velocity ratio?
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PSV in stenosis/PSV proximal segment
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If a graft is abnormal, it may require revision, which may be what?
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-patch
-angioplasty -percutaneous transluminal angioplasty(PTA) -replacement of graft |
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what is the standard for graft survalence?
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-intraoperative to 4 weeks discharge
-2-3 months intervals for 1st year -6-12 months after that |
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Explain assessment for AV fistulas?
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-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 |
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Explain the venous flow at the site of anastamosis and distal in the leg with AVF's? HOw does this effect the extremity?
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-may be pulsitile, and increased velocities
-affected extremity appears edematous -comare affected leg to unaffected leg. |
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what should be documented when scanning an aneurysm?
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-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 |
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when someone has an aortic aneurysm, what other sites should be checked for aneursmal formation?
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-CFA
-Pop A -Illiac arteries |
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WHat should be assessed w/ popiteal entrapment?
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-complete assessment of pp arteries bilaterally including 2D
-compare course of artery from side to side -postition patient prone, and scan distal pop A w/ dorsiflexion observing for decfreased amplitude or obliteration |
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when scanning a PSA,what can you do to rule out branching?
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-doppler of the flow jet at the origin of the neck.
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What do they usually do before they resort to bypassing?
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Try to get patient to change their lifestyle
-prefer to use angioplasty before doing bypass graft |
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what are the treatment options for patients who are not candidates for bypass grafting?
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Non-operative care: limit disease progression
Surgical treatment: -endartectomy(don't do frequently) -bypass grafting -extra-anatomic grafts |
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What are the classifications of bypass grafts?
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-abdominal aortic grafts
-infrainguinal grafts -extra-anatomic bypass grafts |
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what are the presenting symptoms w/ type 1 aorto-illiac disease?
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-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 |
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Explain infrainguinal bypassing?
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-grafting for disease below the groin
-80-90% limb salvage rate |
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what are the indications for infrainguinal bypassing?
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-critical ishemia=tissue nechrosis or ulceration
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extra-anatomic bypass grafts
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-pass through significantly different anatomic pathway than the natural blood vessels they replace
-include axillofemoral, femorofemoral, or a combination of both. |
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What is the outcome of a axillofemoral bypass graft?
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poor patency rate
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what are the indications for extra-anatomic bypass grafts?
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-limited salvage
-intra-abdominal disease where abdominal approach is limited |
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What are the types of arterial bypass grafts?
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-aorto-bifem
-aorto-fem -femoropopiteal -axillofemoral -axillofeoral/femorofemoral -femorotibial -femorofemoral |
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what is the most successful type of bypass graft?
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fem-fem
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What are the types of synthetic and autogenous vein grafts?
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Synthetic=gore-tex, and dacron
Autogenous: -reversed vein grafts -in situ vein grafts -other(umbilical vein, lesser saf) |
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T/F never do BP on a synthetic graft
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true
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Explain the insitu vein graft?
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-usually end-side anastamosis
-uses greater saphenous vein(GSV) -valves are excised -perforaors/tributaries are ligated -prox and distal ends are anastamosed to an artery |
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explain autogenous vein graft
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aka reversed vein grafts:
-GSV harvested -Perforating veins and tributaries are ligated -Vein reversed and implanted as bypass -valves are not excised -small diameter proximally, large diameter distally is advantages |
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How are grafts selected?
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-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 |
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what is the surgical success rate of bypass grafts?
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-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) |
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What are the early complications of bypass grafts?(<30 days)
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-technical
-hypercoagulable state -inadequate flow -hemorrage -limb ishemia(acute thrombosis of reconstruction distal thromboembolic complications-perfusion should increase in 4-6 hours) |
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what are the complications w/ bypass grafts 1-6 months post op, 6-24 months, >24 months
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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 |
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explain acute occlusion w/ bypass grafts?
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-no colorflow or doppler signal
-distal arterial signals show compromise(monophasic) -treated by thrombectomy |
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Explain thrombus as a complication of bypass grafting?
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-can happen when they clamp
-atheromatous debri, or thrombus dislodge after clamping -trash foot occurs as a result |
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explain trash foot?
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-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 |
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what are some complications that can occur immediately post op(usually w/ patients that have underlying medical conditions)
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-renal failure
-intestinal ishemia -spinal cord ishemia -ureteral injury |
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why is there such high survallence on bypass grafts post op?
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-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) |
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what are the goals w/ bypass graft assessment?
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-identify correctable lesions before graft thrombosis
-determine baseline hemodynamics post revascularization -provide objective clinical info to aid in decision making regarding treatment alternatives |
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what pertinent patient hx must be obtain before scanning a post bypass graft patient?
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-type of graft
-graft location and placement-peri anastamotic sites -length of time post-op -any revisions or interventions |
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what is the formula for ABI?
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highest ankle pressure/highest brachial pressure
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Describe the u/s appearance of autogenous vein grafts and synthetic grafts?
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Autogenous:
-GSV lies in the usual normal position -can be insitu or reversed -prevides info about anastomic sites -provides info regarding valves Synthetic grafts: -appear as thick, bright interface w/ a corrugated or rippled wall |
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what are you looking for/what images are you taking in longitudinal and transverse of bypass grafts?
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longitundinal-velocity spectral waveforms
transverse: -change in diameter -intimal hyperplasia -valve leaflets and features -wall thickening -directional changes |
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what should you look for w/ 2D and color of the walls and leaflets of a bypass graft?
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walls:
-contour -thickness -kinks/twists -anastomosis sites valves: -description -location -desciption of valve sinus -mobility of the valves |
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what is the early presentation of intimal hyperplasia?
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-hypoechoic
-narrowing demonstrated on color -elevated velocities and flow disturbances -unexpected kinking/twisting |
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what is the formula for velocity ratio?
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-PSV increase across stenosis/proximal PSV
-walk sample volume box through and take proximal PSV closest to the stenosis where the waveform is normal still. |
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explain the overall dysfunction of graft function?
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-stenosis within 3 months; spontaneous regression seen in <one third of cases; most progress and eventually become occlused
-40% remain stable or progress |
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what are the stages of bypass graft dysfunction?
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early stenosis
worsening stenosis thrombosis |
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what is one way to measure the lenght of a graft stenosis?
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use a tape measure
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what does it mean if the flow in a graft is <40 cm/s?
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graft at increased risk for thrombosis
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What are some things to consider when assessing bypass grafts?
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-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 -NB to identify and decipher the diff. btw normal variations and pathology |
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Name the PSV, EDV, VR, and spectral broadening with <20 to >75% stenosis?
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<20%=PSV <150 VR <1.5; mild spectral broadening
20-50%= PSV <150; EDV<100; VR 1.5-2.5; moderate spectral broadening 50-75%= PSV >150 EDV<100; VR >2.5; post stenotic turbulence(complete cardiac cycle) >75%=PSV>300cm/s; EDV>100; VR>3.5 post stenotic turbulence(complete cycle) |
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What are some factors that need to be corrilated with the diagnostic criteria to determine stenossi?
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-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) |
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what are some serial exam changes to look for with bypass grafts?
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>0.15decrease in ABI
>30cm/sec decrease in graft PSV |
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what is the criteria for a failing illiac system?
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-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 |
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What is the threshold for graft revision?
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PSV>300cm/sec
VR>3.5 Low velocity <40-45cm/sec Decreased ABI |
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what is the thrombotic threshold velocity?
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PSV <45 or >30cm/sec diff from prev./ exam
PSV>200 may be indicitive of graft failure |
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what are the late complications of graft failure?
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occlusion
anastamotic false aneurysm impotence imfections aortoenteric fistula |
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explain Graft occlusion
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5-10% chance 5 yrs post op
15-30% chance 10 years post op most common late complication |
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Explain graft occlusion for Aortofemoral grafts:
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-occlusion will affect one limb
-resulting ishemia more severe than prior -reoperation urgent for limb salvage |
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Explain anatomotic false anurysms, and their contributing factors?
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-second most common complication
-1-5% -most common at the femoral anastamosis Contributing 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 |
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explain impotence as a late factor of bypass graft failure?
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-25% from iatrogenic causes
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explain infection as a late complication of bypass grafts? What are the contributing factors?
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-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 |
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explain Aortoenteric fistula and the treatment of it?
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Aortoenteric fistula:
-assoc w/ GI hemorrahge -occurs @ 4th part of duodenum because it crosses over the AO -primary cause is rupture of aneurysms directly into the organs Treament: -emergency surgery and repair of the affected intestinal organ and repair of the ao |
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If a graft has less than expected perfusion, what could have happend?
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ther surgeon could have missed a perforating vein and thus an AV fistula exists
-decreased amount of blood available to the lower limb -tremendous turbulence |
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how often should velocities be measured in a graft? @ what ratio should you be concerned?
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every 4-5cm
If ratio btw 2 measurements is <2, it's free of disease -if its >2, 50-75% stenosis -if >3, at least 75% stensosis |
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if a large(diameter) segment of a graft has a low velocity(40-45cm/sec), should you be concerned?
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no, because blood flows slower in larger vessels
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If you see retrograde flow in the proximal direction in the native arterial segment at a distal anastomosis, what should you think?
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-not unusual
-caused by low pressure in the diseased nateive vessel and the fact that blood flows from low to high presure areas. -the segment of native artery distal to the anastamosis carries flow in the normal direction towards the feet |
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valvulotome
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instrament used to take out valves
-stubs of valves are stll left in place |
