When is toe-brachial index preferred over ABI?

• A. In patients with calcified, incompressible arteries (e.g., diabetes, older adults) where ABI may be falsely elevated
• B. In patients with severe venous insufficiency
• C. In pediatric patients with suspected PAD
• D. In athletes with normal ABI

Answer: (A)

When arteries in the leg are calcified and incompressible, the ankle-brachial index can be falsely elevated and unreliable for detecting PAD. This happens in people with diabetes or older adults where medial calcification stiffens the tibial and ankle vessels, so cuff pressures don’t reflect true arterial flow. The toe arteries are less affected by this calcification and remain compressible, allowing a more accurate measurement when you compare toe pressures to the arm. So the toe-brachial index is preferred because it uncovers distal arterial disease that the ABI might miss or misrepresent. The other situations don’t specifically address the issue of arterial incompressibility: venous insufficiency alters venous pressures, pediatric PAD is uncommon, and athletes with a normal ABI don’t require an alternative index.