RVT - Registered Vascular Technologist Peripheral Venous Testing Questions and Answers 1 — Questions and Answers
Question 1: A 68-year-old male is referred for a preoperative vein mapping of the right leg prior to coronary artery bypass grafting (CABG). Which of the following is the minimum acceptable diameter for the Greater Saphenous Vein (GSV) to be considered a suitable conduit?
- 1.0 mm
- 1.5 mm
- 2.0 mm (Correct answer)
- 3.5 mm
Correct answer: 2.0 mm
For a vein, most commonly the Greater Saphenous Vein, to be used as a conduit for bypass surgery, it must meet certain size criteria to ensure long-term patency. A diameter of 2.0 to 2.5 mm is generally considered the minimum acceptable size for a successful graft. Veins smaller than this have a higher risk of failure.
Question 2: During a lower extremity venous duplex examination for suspected deep vein thrombosis (DVT), the primary diagnostic criterion is:
- Demonstration of reversed flow with color Doppler.
- Lack of complete coaptation of the vein walls with transducer pressure. (Correct answer)
- The presence of a continuous, non-phasic waveform in the common femoral vein.
- Visualization of echogenic material within the vein lumen.
Correct answer: Lack of complete coaptation of the vein walls with transducer pressure.
The most reliable and primary criterion for diagnosing a deep vein thrombosis (DVT) with ultrasound is the inability to fully compress the vein walls together with gentle transducer pressure. While visualization of echogenic material is a supporting finding, and Doppler abnormalities can suggest obstruction, the failure to coapt is the definitive sign of an intraluminal thrombus.
Question 3: A patient presents with left lower extremity swelling and pain. Duplex ultrasound reveals compression of the left common iliac vein by the overlying right common iliac artery. This finding is most consistent with:
- Phlegmasia Cerulea Dolens
- Paget-Schroetter Syndrome
- Klippel-Trenaunay Syndrome
- May-Thurner Syndrome (Correct answer)
Correct answer: May-Thurner Syndrome
May-Thurner Syndrome (MTS), also known as iliac vein compression syndrome, is a condition where the left common iliac vein is compressed by the right common iliac artery against the lumbar spine. This compression can impede venous outflow from the left leg, leading to swelling, pain, and an increased risk of DVT.
Question 4: When performing a duplex ultrasound to evaluate for venous insufficiency, which patient position is considered optimal for eliciting venous reflux?
- Supine with the head of the bed flat.
- Reverse Trendelenburg at a 15-degree angle.
- Standing with weight on the contralateral leg. (Correct answer)
- Left lateral decubitus.
Correct answer: Standing with weight on the contralateral leg.
To accurately assess for venous reflux, the patient should be positioned to maximize hydrostatic pressure in the lower extremities, which challenges the vein valves. The standing position is the gold standard as it allows gravity to have its full effect. If standing is not possible, a steep reverse Trendelenburg position is an alternative, but standing is preferred.
Question 5: Which of the following describes the proper technique for performing compressions during a lower extremity venous DVT study?
- Apply pressure in the longitudinal plane every 5 cm.
- Compress the vein in the transverse plane every 1-2 cm. (Correct answer)
- Use color Doppler to confirm coaptation at the groin, popliteal, and ankle.
- Apply compressions only to symptomatic areas.
Correct answer: Compress the vein in the transverse plane every 1-2 cm.
The standard protocol for a lower extremity DVT evaluation involves applying direct pressure with the transducer in the transverse plane at intervals of 1-2 cm along the deep veins. This ensures that the entire length of the major deep veins is assessed for compressibility, as a thrombus can be focal.
Question 6: A sonographer is evaluating a patient with a history of DVT one year ago. The common femoral vein appears patent but contains echogenic, thickened walls and the enclosed valve leaflets are immobile. These findings are most characteristic of:
- An acute, non-occlusive thrombus.
- Venous aneurysm.
- Chronic post-thrombotic changes. (Correct answer)
- An arteriovenous fistula.
Correct answer: Chronic post-thrombotic changes.
Chronic post-thrombotic changes are the long-term sequelae of a DVT. Sonographically, this appears as thickened, echogenic vein walls, immobile or 'frozen' valve cusps, and possible residual, organized thrombus (synechiae) that may recanalize. The vein is typically compressible, unlike in an acute DVT.
RVT - Registered Vascular Technologist Peripheral Venous Testing Questions and Answers 1
A 68-year-old male is referred for a preoperative vein mapping of the right leg prior to coronary artery bypass grafting (CABG).
Which of the following is the minimum acceptable diameter for the Greater Saphenous Vein (GSV) to be considered a suitable conduit?