Most commonly used noninvasive test in the diagnosis of peripheral arterial occlusive disease.
Defined as the ratio of the ankle systolic blood pressure to the brachial artery systolic blood pressure.
The systolic blood pressure increases distally in the arterial circulation and is higher in the lower than in the upper limb.
With hemodynamically significant stenosis, there is a decline in the systolic pressure distal to the obstruction that is proportional to its severity.
The ratio of systolic pressure measured at the brachial artery and at the ankle arteries has been adopted to diagnosed peripheral arterial disease.
A normal supine resting ABI is 1.0, with values of 0.8 to 0.9, 0.5 to 0.8 and <0.5 correlating with mild, moderate and severe peripheral arterial occlusive disease.
An independent predictor of cardiovascular mortality and cerebrovascular events.
A normal resting ABI does not rule out peripheral arterial disease and an exercise ABI should be obtained if claudication is suspected.
A low ABI is associated with concomitant coronary and cerebrovascular disease, and in healthy persons an increased risk of vascular events, independent of cardiovascular risk factors(Fowkes FG).
A meta-analysis of 16 studies of healthy individuals, the 10 year risk of major coronary events in men with an ABI of 0.90 or less was 27% compared with 9% in those with an ABI in the normal range(Fowkes FG).
A meta-analysis of 16 studies of healthy individuals, the 10 year risk of major coronary events in women with an ABI of 0.90 or less was 19% compared with 6% in those with an ABI in the normal range(Fowkes FG).
The Aspirin for Asymptomatic Atherosclerosis trial involving 28980 men and women age 50-75 years free of clinical cardiovascular disease, with 3350 patients with low ABI treated with 100 mg of daily aspirin compared to placebo: no difference was noted in vascular events.