RVT Peripheral Arterial Physiologic Testing 4

Question 1

Photoplethysmography (PPG) is used to assess digital perfusion. What does a flattened, obstructive waveform on digital PPG indicate?

Accepted Answer

Significant arterial obstruction reducing pulsatile flow to the digit

Answer

A flat or nearly absent PPG waveform indicates severely reduced or absent pulsatile arterial inflow to the digit, consistent with significant obstruction or critical ischemia.

Question 2

Which condition can produce a falsely HIGH ABI, potentially masking severe peripheral arterial disease?

Accepted Answer

Medial arterial calcification (Mönckeberg sclerosis)

Answer

Medial calcification renders vessels incompressible, requiring supra-systolic cuff pressures that never fully occlude the artery, resulting in ABI values >1.3 despite significant disease.

Question 3

During peripheral arterial physiologic testing, what is the significance of a 'pole test' (elevation test)?

Accepted Answer

It determines the critical closing pressure of limb arteries by elevating the limb until Doppler signal disappears

Answer

The pole test elevates the limb to determine the height at which Doppler signal disappears, estimating the effective perfusion pressure in critically ischemic limbs when cuff pressures are unreliable.

Question 4

A patient with Raynaud's phenomenon undergoes cold stimulation testing. Which finding would confirm vasospastic disease rather than fixed obstruction?

Accepted Answer

Complete recovery of digital waveform amplitude after rewarming to 37°C

Answer

Vasospastic Raynaud's phenomenon is characterized by reversible digital vessel spasm that resolves completely with rewarming, distinguishing it from fixed structural obstruction.

Question 5

What hemodynamic principle explains why a 50% diameter stenosis may not produce a resting pressure gradient but becomes hemodynamically significant during exercise?

Accepted Answer

Bernoulli's equation: pressure loss is proportional to flow velocity squared

Answer

Pressure loss across a stenosis is proportional to flow velocity squared (Bernoulli), so the increased flow demanded during exercise dramatically amplifies pressure gradient across a previously subcritical stenosis.

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RVT Peripheral Arterial Physiologic Testing 4