Femoral plaque burden by ultrasound is a better indicator of significant coronary artery disease over ankle brachial index

The ankle-brachial index is a commonly used tool for identifying peripheral artery disease for cardiovascular risk stratification. An abnormal ankle-brachial index occurs only following extensive peripheral atherosclerosis occlusion, and thus has poor sensitivity for coronary atherosclerosis. There is a critical need for the development of tools that can detect risk prior to advanced stages of atherosclerosis. We sought to determine the sensitivity of femoral ultrasound for coronary artery disease. In this prospective, cross-sectional study, participants (n = 124) underwent ankle-brachial index measurement and femoral ultrasound for assessment of intima-media thickness, maximal plaque height, and total plaque area following coronary angiography. Receiver operating characteristic areas under the curve were plotted for identifying significant coronary artery disease (≥ 50% stenosis). Logistic regression was utilized to evaluate associations. 64% of participants had significant, angiography-confirmed coronary artery disease. Femoral ultrasound plaque area yielded the highest area under the curve for detecting significant coronary disease (area under the curve = 0.731). In contrast, an abnormal ankle-brachial index (≤ 0.90) produced an area under the curve of 0.568. Femoral ultrasound had a higher sensitivity (85%) than the ankle-brachial index (25%) for ruling out significant coronary artery disease. Both ankle-brachial index and femoral ultrasound have similar capacity to detect peripheral artery disease. Femoral ultrasound has a significantly greater discriminatory power than ankle-brachial index to detect clinically significant coronary artery disease. Ultrasound-captured femoral plaque burden directly delineates the extent of peripheral arterial disease and is better at ruling out significant coronary atherosclerosis than the ankle-brachial index.