Peripheral Vascular Assessment Flashcards

Which physiologic principle explains the increased velocity at a stenosis as measured by Doppler ultrasound?

Answer: Bernoulli's Principle and the continuity equation

The continuity equation (conservation of mass) combined with Bernoulli's Principle dictates that flow velocity must increase as the vessel lumen narrows to maintain constant volume flow.

In a patient with intermittent claudication, post-exercise ankle pressures typically show what change compared to resting values?

Answer: Significant decrease in ankle pressure

Exercise-induced vasodilation increases demand distal to a stenosis; since the stenosis limits flow augmentation, ankle pressures fall significantly after exercise in PAD patients.

Chronic venous insufficiency is most accurately graded using which classification system?

Answer: CEAP classification

The CEAP (Clinical, Etiology, Anatomy, Pathophysiology) classification is the internationally accepted standard for grading and communicating chronic venous disease severity.

Which finding on carotid duplex ultrasound is most consistent with a string sign (near-occlusion) rather than complete occlusion of the internal carotid artery?

Answer: Very low amplitude, slow flow detectable only with power Doppler or low PRF settings

Near-occlusion (string sign) preserves a trickle of flow detectable only with sensitive power Doppler or very low PRF, distinguishing it from true occlusion where no flow is detected.

A patient undergoes lower extremity venous mapping for bypass surgery. Which vein is preferred as a conduit and what minimum diameter is generally required?

Answer: Great saphenous vein; minimum 3 mm

The great saphenous vein is the preferred bypass conduit, and a minimum diameter of 3 mm is generally required for adequate long-term graft patency.

During mesenteric artery duplex evaluation, a fasting superior mesenteric artery (SMA) PSV greater than what value suggests significant stenosis?

Answer: 275 cm/s

A fasting SMA PSV greater than 275 cm/s is the established threshold for diagnosing hemodynamically significant superior mesenteric artery stenosis.

Which of the following best describes the spectral Doppler appearance of a normal common femoral artery waveform in a resting adult?

Answer: Triphasic with forward systolic flow, brief reverse flow, and forward diastolic flow

A normal common femoral artery at rest displays a triphasic waveform reflecting the high-resistance nature of the resting peripheral vascular bed.