Significance of an abnormal ankle-brachial index in patients with established coronary artery disease with and without associated diabetes mellitus

Abstract

An abnormal ankle-brachial index (ABI) is associated with higher risk for future cardiovascular (CV) events; however, it is unknown whether this association is true in patients with established coronary artery disease (CAD) and associated diabetes mellitus (DM). We evaluated 679 patients with stable CAD enrolled in the Excellence in Peripheral Arterial Disease and Veterans Affairs North Texas Healthcare System peripheral arterial disease databases. ABI and 12-month major adverse CV events (MACEs, a composite of all-cause death, nonfatal myocardial infarction, need for repeat coronary revascularization, and ischemic stroke) were assessed. Cox proportional hazard models were used to assess the association of ABI and DM with subsequent CV events. An abnormal ABI (<0.9 or >1.4) was present in 72% of patients with stable CAD and 68% had DM. Using patients without DM and normal ABI as reference, the adjusted hazard ratio for 12-month MACE was 1.7 (95% confidence interval [CI] 0.71 to 4.06) for patients with DM and normal ABI; 2.03 (95% CI 0.83 to 4.9) for patients without DM with abnormal ABI; and 4.85 (95% CI 2.22 to 10.61) for patients with DM and abnormal ABI. In conclusion, in patients with stable CAD, an abnormal ABI confers an incremental risk of MACE in addition to DM and traditional CV risk factors.