RVT Ultrasound-Guided Procedures and Intraoperative Assessment

Question 1

What is the preferred ultrasound-guided intervention for an iatrogenic femoral pseudoaneurysm that fails compression therapy?

Accepted Answer

Ultrasound-guided thrombin injection into the pseudoaneurysm sac

Answer

Ultrasound-guided thrombin injection is the first-line treatment for pseudoaneurysms that do not respond to compression. A small volume of thrombin (100–500 units) is injected directly into the sac under real-time imaging, inducing rapid thrombosis while the neck is monitored to prevent inadvertent arterial embolization.

Question 2

During intraoperative TCD monitoring of a carotid endarterectomy, which finding should prompt the surgeon to insert an intraluminal shunt?

Accepted Answer

MCA mean velocity decrease of more than 50% from pre-clamp baseline

Answer

A >50% drop in ipsilateral MCA mean velocity after carotid cross-clamping indicates inadequate collateral perfusion and cerebral ischemia risk. This threshold is widely used as the criterion for shunt placement to maintain cerebral blood flow during the endarterectomy.

Question 3

What is the primary duplex role during endovenous thermal ablation (EVTA) of the great saphenous vein?

Accepted Answer

Guiding catheter tip placement and detecting endothermal heat-induced thrombosis (EHIT) post-procedure

Answer

Ultrasound guides correct catheter positioning (typically 2 cm distal to the saphenofemoral junction) and monitors tumescent anesthesia placement. Post-ablation, the technologist scans for EHIT — thrombus propagation into the deep system — which can occur in the first few days and requires classification and follow-up.

Question 4

Which intraoperative duplex finding after infrainguinal bypass graft creation most likely warrants immediate surgical revision?

Accepted Answer

Focal peak systolic velocity ratio greater than 3:1 across an anastomotic segment

Answer

A PSV ratio >3:1 across a focal segment indicates a hemodynamically significant stenosis (≥75% diameter reduction). When found intraoperatively before the wound is closed, it signals a technical defect — suture narrowing, intimal flap, or kinking — that should be corrected immediately to prevent early graft failure.

Question 5

Ultrasound-guided compression repair of a femoral pseudoaneurysm is MOST likely to fail or be contraindicated when the patient is:

Accepted Answer

Undergoing anticoagulation therapy

Answer

Anticoagulation significantly impairs the ability to thrombose the pseudoaneurysm sac during compression, making the procedure much less effective and requiring prolonged compression times. In anticoagulated patients, ultrasound-guided thrombin injection is the preferred alternative because it does not depend on the coagulation cascade.

(RVT) Registered Vascular Technologist Practice Test

(RVT) Registered Vascular Technologist Practice Test

RVT Ultrasound-Guided Procedures and Intraoperative Assessment