Renal Dialysis Fistulas and Grafts Flashcards
(22 cards)
What are some indications of an US with renal dialysis?
Inadequate dialysis, thrombosed access, perigraft mass, upper extremity swelling, decreased thrill or pulse, suspected steal, infection, bleeding, post revision f/up
What are the methods of evaluation for dialysis?
Ultrasound, arteriography, fistulography
What is the US protocol for a dialysis fistula/graft?
Record PSV at native artery prox, arterial anastomosis, graft/fistula, venous anastomosis, venous outflow
What does a steal look like sonographically?
Retrograde flow in the inflow artery distal to the anastomosis, large venous outflow branches
Where is an increased chance of thrombus forming?
SCV
What is the waveform like in the arterial limb?
Increased velocity, continuous forward flow, marked spectral broadening
What is the waveform like in the venous limb?
Slightly lower velocity than arterial limb
What is the most common site of stenosis/thrombosis?
Venous limb
What is a normal graft/AVF PSV?
100-400 cm/s
What is a normal graft/AVF EDV?
60-200 cm/s
What type of flow and resistance are seen in a normal graft/AVF?
Increased flow, decreased resistance
What is the sonographic appearance of an occlusion?
No flow in graft or outflow vein distal to fistula, increased resistance in artery leading into graft/fistula (staccato), decreased venous outflow
What is the PSV of a graft stenosis or fistula?
> 400 cm/s
What is the velocity ratio >/= 50% of a graft or fistula stenosis?
> /= 2:1
What is the velocity ratio >/= 75% of a graft of fistula stenosis?
> /= 3:1
What graft flow volume indicates pending graft failure?
<350 ml/min
What graft flow volume indicates an increased risk of graft failure?
<500 ml/min
What is a normal flow range for a graft?
> 800 ml/min
What graft flow volume indicates possible CHF?
> 1500 ml/min
What is a normal AVF flow volume w/a 4 mm outflow vein?
> 500 ml/min
What is a normal AVF flow volume?
> 800 ml/min
What are the most common abnormalities of a graft or AVF?
Venous outflow obstruction, venous anastomosis stenosis (50-90%), pseudoaneurysm, diffuse aneurismal dilation, hematoma, perigraft abscess, intimal flaps (from needle punctures), arterial anastomotic stenosis (15%)
