CVT Peripheral Vascular Assessment 2 — Questions and Answers
Question 1: Which waveform characteristic on a peripheral arterial Doppler study is most indicative of a hemodynamically significant proximal stenosis?
- Triphasic waveform with sharp systolic peak
- Monophasic waveform with prolonged systolic upstroke and absent diastole (Correct answer)
- Biphasic waveform with high-amplitude reverse flow
- Multiphasic waveform with rapid upstroke
Correct answer: Monophasic waveform with prolonged systolic upstroke and absent diastole
A monophasic waveform with a prolonged systolic upstroke (tardus-parvus pattern) distal to a stenosis indicates significant proximal arterial obstruction.
Question 2: During venous duplex imaging of the lower extremity, which maneuver is used to assess valve competence?
- Valsalva maneuver (Correct answer)
- Hyperemia test
- Reactive hyperemia
- Treadmill exercise
Correct answer: Valsalva maneuver
The Valsalva maneuver increases intra-abdominal pressure, temporarily halting venous flow, and upon release reveals reflux in incompetent valves.
Question 3: What is the normal duration threshold for pathologic venous reflux in the great saphenous vein?
- Greater than 0.5 seconds (Correct answer)
- Greater than 1.0 second
- Greater than 2.0 seconds
- Greater than 3.0 seconds
Correct answer: Greater than 0.5 seconds
Reflux duration exceeding 0.5 seconds in the great saphenous vein is considered pathologic and indicative of valvular incompetence.
Question 4: A patient presents with acute limb ischemia. Which of the '6 P's' is considered the most urgent sign requiring immediate intervention?
- Pain
- Pallor
- Paralysis (Correct answer)
- Pulselessness
Correct answer: Paralysis
Paralysis (motor deficit) indicates advanced ischemia with muscle and nerve involvement, requiring emergent revascularization to prevent irreversible limb loss.
Question 5: When performing a renal artery duplex study, a peak systolic velocity (PSV) ratio of the renal artery to the aorta (RAR) greater than what value indicates significant renal artery stenosis?
- 1.5
- 2.0
- 3.5 (Correct answer)
- 5.0
Correct answer: 3.5
A renal-aortic ratio (RAR) greater than 3.5 is the standard threshold for diagnosing hemodynamically significant renal artery stenosis.
Question 6: In a patient with suspected subclavian steal syndrome, which finding on duplex ultrasound confirms the diagnosis?
- Antegrade flow in the ipsilateral vertebral artery
- Retrograde or bidirectional flow in the ipsilateral vertebral artery (Correct answer)
- Increased PSV in the subclavian artery distal to the stenosis
- Monophasic flow in the contralateral vertebral artery
Correct answer: Retrograde or bidirectional flow in the ipsilateral vertebral artery
Subclavian steal syndrome is confirmed by retrograde or bidirectional (to-and-fro) flow in the vertebral artery ipsilateral to the subclavian stenosis or occlusion.
Question 7: Which Doppler angle should be used when obtaining velocity measurements in peripheral vascular studies to ensure accuracy?
- 0 degrees
- 45 degrees
- 60 degrees or less (Correct answer)
- 90 degrees
Correct answer: 60 degrees or less
Doppler angles of 60 degrees or less are required for accurate velocity measurements; angles greater than 60 degrees introduce significant cosine error.
CVT Peripheral Vascular Assessment 2
Which waveform characteristic on a peripheral arterial Doppler study is most indicative of a hemodynamically significant proximal stenosis?