Peripheral Arterial Physiologic Testing Flashcards

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

Answer: Significant arterial obstruction reducing pulsatile flow to the digit

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.

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

Answer: Medial arterial calcification (Mönckeberg sclerosis)

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.

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

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

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.

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

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

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

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

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

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.

Which clinical scenario would MOST warrant transcutaneous oxygen pressure (TcPO2) measurement as part of peripheral arterial physiologic testing?

Answer: Predicting wound healing potential in a patient with a non-healing foot ulcer

TcPO2 measures tissue oxygenation at the skin surface and is used to predict amputation wound healing potential; values <20-30 mmHg predict poor healing.

In segmental limb pressure testing, what finding is characteristic of isolated popliteal artery disease?

Answer: Gradient between above-knee and below-knee segmental pressures with normal thigh pressures

Isolated popliteal disease produces a pressure drop between the above-knee and below-knee cuff levels with normal proximal thigh pressures, localizing disease to the popliteal segment.