Which of the following is/are true with respect to ankle blood pressure and ankle brachial index (ABI)?

a. An ABI of less than 0.92 almost always indicates hemodynamically significant arterial disease

b. Claudicants have a wide range of ABIs with average values of 0.6 +/– 0.15

c. In limbs with rest pain the mean ABI is typically 0.25 +/– 0.13

d. In limbs with impending gangrene ABIs seldom exceed 0.25 and average about 0.05 +/– 0.08

The normal person’s resting ankle brachial blood pressure usually exceeds brachial blood pressure. In persons with stenotic lesions that do not reduce the diameter of the arterial lumen by more than 50% there may be no change in resting ankle brachial blood pressure. Absolute ankle pressures of less than 40 mmHg always indicate severe arterial compromise regardless of the ABI. The ranges given above have been empirically derived from assessing large numbers of patients. When the arteries are incompressable secondary to calcification spuriously high ankle pressures may be obtained.