An abnormal ankle-brachial index is defined as which value?

An abnormal ankle-brachial index is defined as which value?

• A. < 0.9
• B. > 1.3
• C. 1.0
• D. 0.95

Answer: (A)

The key idea is that the ankle-brachial index shows how well blood is getting to the legs by comparing ankle and arm pressures. A normal perfusion level is typically around 1.0 (roughly 1.0 to 1.3). When the ABI falls below 0.9, it indicates impaired blood flow to the legs, i.e., peripheral artery disease. So the value that defines an abnormal ABI—signaling reduced perfusion—is less than 0.9. Values around 1.0 or higher are normal, while a very high value (above about 1.3) can mean arteries are noncompressible due to calcification, which makes the measurement unreliable but is not the typical indication of PAD.

The key idea is that the ankle-brachial index shows how well blood is getting to the legs by comparing ankle and arm pressures. A normal perfusion level is typically around 1.0 (roughly 1.0 to 1.3). When the ABI falls below 0.9, it indicates impaired blood flow to the legs, i.e., peripheral artery disease. So the value that defines an abnormal ABI—signaling reduced perfusion—is less than 0.9. Values around 1.0 or higher are normal, while a very high value (above about 1.3) can mean arteries are noncompressible due to calcification, which makes the measurement unreliable but is not the typical indication of PAD.