Relation between the ankle-brachial index and the complexity of coronary artery disease in older patients

BACKGROUND: In the elderly, the ankle-brachial index (ABI) has greater than 90% sensitivity and specificity for peripheral artery disease identification. A well-known relation exists between peripheral artery disease and the number of diseased coronary vessels. Yet, other anatomical characteristics have important impacts on the type of treatment and prognosis. PURPOSE: To determine the relation between ABI and the complexity of coronary artery disease, by different anatomical classifications. METHODS: This study was a prospective analysis of patients ≥65 years old who were undergoing elective coronary angiography for ischemic coronary disease. The ABI was calculated for each leg, as the ratio between the lowest ankle pressure and the highest brachial pressure. The analysis of coronary anatomy was performed by three interventional cardiologists; it included classification of each lesion with >50% diameter stenosis, according to the American Heart Association criteria, and calculation of the SYNTAX score. RESULTS: The study recruited 204 consecutive patients (median age: 72.5 years). Stable angina was present in 51% of patients. Although only 1% of patients reported peripheral artery disease, 45% exhibited an abnormal ABI. The number of lesions per patient, the number of patients with complex lesions, and the median SYNTAX scores were greater in the group with abnormal ABI. However, among 144 patients with obstructive coronary artery disease, despite abnormal ABI being able to identify a higher rate of patients with B2 or C type lesions (70.9% versus 53.8%; P=0.039), the mean SYNTAX scores (13 versus 9; P=0.14), and the proportion of patients with SYNTAX score >16 (34.2% versus 27.7%; P=0.47), were similar, irrespective of ABI. CONCLUSION: In patients ≥65 years old the presence of peripheral artery disease could discriminate a group of patients with greater occurrence of B2 and C type lesions, but similar median SYNTAX score.