Renal Dialysis Fistulas and Grafts

Question 1

What are some indications of an US with renal dialysis?

Answer 1

Inadequate dialysis, thrombosed access, perigraft mass, upper extremity swelling, decreased thrill or pulse, suspected steal, infection, bleeding, post revision f/up

Question 2

What are the methods of evaluation for dialysis?

Answer 2

Ultrasound, arteriography, fistulography

Question 3

What is the US protocol for a dialysis fistula/graft?

Answer 3

Record PSV at native artery prox, arterial anastomosis, graft/fistula, venous anastomosis, venous outflow

Question 4

What does a steal look like sonographically?

Answer 4

Retrograde flow in the inflow artery distal to the anastomosis, large venous outflow branches

Question 5

Where is an increased chance of thrombus forming?

Answer 5

SCV

Question 6

What is the waveform like in the arterial limb?

Answer 6

Increased velocity, continuous forward flow, marked spectral broadening

Question 7

What is the waveform like in the venous limb?

Answer 7

Slightly lower velocity than arterial limb

Question 8

What is the most common site of stenosis/thrombosis?

Answer 8

Venous limb

Question 9

What is a normal graft/AVF PSV?

Answer 9

100-400 cm/s

Question 10

What is a normal graft/AVF EDV?

Answer 10

60-200 cm/s

Question 11

What type of flow and resistance are seen in a normal graft/AVF?

Answer 11

Increased flow, decreased resistance

Question 12

What is the sonographic appearance of an occlusion?

Answer 12

No flow in graft or outflow vein distal to fistula, increased resistance in artery leading into graft/fistula (staccato), decreased venous outflow

Question 13

What is the PSV of a graft stenosis or fistula?

Answer 13

> 400 cm/s

Question 14

What is the velocity ratio >/= 50% of a graft or fistula stenosis?

Answer 14

> /= 2:1

Question 15

What is the velocity ratio >/= 75% of a graft of fistula stenosis?

Answer 15

> /= 3:1

Question 16

What graft flow volume indicates pending graft failure?

Answer 16

<350 ml/min

Question 17

What graft flow volume indicates an increased risk of graft failure?

Answer 17

<500 ml/min

Question 18

What is a normal flow range for a graft?

Answer 18

> 800 ml/min

Question 19

What graft flow volume indicates possible CHF?

Answer 19

> 1500 ml/min

Question 20

What is a normal AVF flow volume w/a 4 mm outflow vein?

Answer 20

> 500 ml/min

Question 21

What is a normal AVF flow volume?

Answer 21

> 800 ml/min

Question 22

What are the most common abnormalities of a graft or AVF?

Answer 22

Venous outflow obstruction, venous anastomosis stenosis (50-90%), pseudoaneurysm, diffuse aneurismal dilation, hematoma, perigraft abscess, intimal flaps (from needle punctures), arterial anastomotic stenosis (15%)