Which statement explains why the Ankle-Brachial Index can be unreliable in patients with arterial calcification, and what alternative test can be used?

• A. Calcified, noncompressible arteries can yield falsely high or normal ABI; Toe-Brachial Index or duplex assessment can be used as alternatives.
• B. ABI is always reliable in calcified vessels; use pedal Doppler assessment as replacement.
• C. Low blood flow in calcified arteries reduces ABI; duplex is not helpful.
• D. Arterial calcification shortens vessel length affecting ABI; use CT angiography instead.

Answer: (A)

Arterial calcification makes the arteries noncompressible, so the ankle pressure used in the ABI can be falsely high or normal even when there is peripheral artery disease. Because the cuff can’t compress these calcified vessels, the ABI loses its reliability. The Toe-Brachial Index is a more dependable alternative in this situation since the digital arteries are less affected by calcification, providing a closer reflection of perfusion. Duplex ultrasound is another helpful option because it directly assesses blood flow and vessel patency without relying on compressible ankle arteries.