Ch. 14-16 Vascular Flashcards
What vessels are used for autogenous vein bypass graft
GSV usually, but can also use SSV or cephalic V
Orthograde BG involves
lyzing valves
Retrograde BG involves
flipping the vein
When you flip the vein, valves
do not need to be removed
How is a vein flip performed
large end of the vein anastomosed to small end of artery (and vice versa)
When you flip the vein, it is completely
removed from its nature tissue bed
During the first 30 days, what technical problems are more likely to occur with bypass graft failure
retained valve, intimal flap, graft entrapment
Patients who need more frequent surveillance are
intraoperative revision
What is the proper doppler technique when scanning bypass graft
60-degree angles or less, place sample volume in center of vessel, sample volume should be small
If angles less than 60 degrees are used in previous exams,
angles should be duplicated in follow-up exams
If both antegrade and retrograde are seen, it is most likely indicative of
retrograde flow through prox outflow artery
What is most likely to occur any point along bypass conduit
myointimal hyperplasia
Aneurysms can be
focal or diffuse
What should be used to document flow within incidental findings
color
What may be present with color imaging in a stenosis
aliasing
color can mask
small wall defects
What are the normal bypass waveform characteristics
multi-phasic, sharp upstroke and narrow systolic peak, HIGH RESISTANCE WF CHARACTERISTICS, REVERSE FLOW IN EARLY DIASTOLE
Occurs when branch of great saphenous vein is left unligated
arteriovenous fistula
Abnormal connection between artery and vein
arteriovenous fistula
What is the doppler spectrum PROXIMAL to fistula
will display low resistance pattern with continuous antegrade flow in diastole
What is the doppler spectrum DISTAL to fistula
little to no diastolic flow will be present
Spectral analysis of distal stenosis or occlusion can progress to
staccato waveform
What is the indicator of a staccato waveform
minimal forward flow in systole
What is the criteria for stenosis categorization
PSV ratio of 3.5 and PSV >300 cm/s consistent with a greater than or equal to 75% stenosis
What is the normal mean graft flow velocity (GFV)
greater than 45 cm/s
A decrease in GFV ______ indicates pending graft failure
> 30 cm/s
What does PTA stand for
percutaneous transluminal angioplasty
What is the most common endovascular treatment
PTA