Vascular Mod 12

Question 1

Indication to for access duplex evaluation

Answer 1

1) dynamic venous pressure > 200 mmHg
2) recirculation > 12%
3) urea reduction ratio < 60%
4) water hammer pulse in access
5) pulsatile mass
6) loss of thrill
7) steal
8) venous hypertension/edema
9) check maturity

Question 2

Normal findings of a fistula duplex

Answer 2

1) low resistance waveform
2) EDV 1/2 to 2/3 PSV
3) antegrade flow in artery distal to proximal anast
4) PSV 100-200 cm/s throughout access
5) turbulent flow pattern
6) uniform access diameter > 4mm
7) absence of intraluminal defects
8) absence of aneurysm dilatation or wall disruption
9) respiratory phasicity and increased pulsatility in venous outflow system

Question 3

Normal volume flow in fistula

Answer 3

> 500-600 ml/min

Question 4

Normal velocity ratio of fistula to inflow

Answer 4

< 3

Question 5

Volume flow measurement in fistula needs these metrics

Answer 5

1) mean velocity

2) diameter measurement

Question 6

What is the DBI cutoff for risk of fistula steal

Answer 6

< 0.6