RVT Post-Intervention and Grafts 2

Question 1

Which PSV ratio across a graft stenosis is most consistent with a hemodynamically significant (>50%) lesion?

Accepted Answer

PSV ratio >2.0

Answer

A peak systolic velocity ratio greater than 2.0 at the stenosis versus the adjacent graft segment indicates a hemodynamically significant stenosis of greater than 50%.

Question 2

On duplex surveillance of a PTFE above-knee femoropopliteal bypass graft, a focal PSV of 380 cm/s with a PSV ratio of 3.8 is found. What is the most appropriate next step?

Accepted Answer

Refer for angiography or intervention

Answer

A PSV >300 cm/s with a ratio >3.5 indicates a severe stenosis (>70%), warranting urgent referral for angiographic evaluation and possible intervention.

Question 3

A vein graft exhibiting low-velocity, monophasic waveforms throughout its length without a focal stenosis most likely represents which condition?

Accepted Answer

Impending graft failure due to inflow disease or low-flow state

Answer

Uniformly low velocities with monophasic waveforms throughout a graft suggest poor inflow or high outflow resistance, placing the graft at risk for thrombosis.

Question 4

During carotid endarterectomy surveillance, which finding at the endarterectomy site is MOST concerning for restenosis requiring intervention?

Accepted Answer

ICA PSV >300 cm/s with ICA/CCA ratio >4.0

Answer

An ICA PSV >300 cm/s combined with an ICA/CCA ratio >4.0 indicates severe (>70%) post-CEA restenosis, which typically warrants intervention.

Question 5

A patient presents 2 years after renal artery stent placement. Duplex shows an intrarenal acceleration time of 0.09 seconds with a tardus-parvus waveform. What does this suggest?

Accepted Answer

Significant in-stent restenosis proximal to the sampling site

Answer

An acceleration time >0.08 seconds with a tardus-parvus pattern indicates a significant proximal stenosis damping flow to the renal parenchyma, suggesting in-stent restenosis.

(RVT) Registered Vascular Technologist Practice Test

(RVT) Registered Vascular Technologist Practice Test

RVT Post-Intervention and Grafts 2