Abstract 9416: Undiagnosed Peripheral Arterial Disease (PAD) is Common in Patients Referred for Stress Tests Without a History of Atherosclerotic Heart Disease

Abstract

Background: The ankle brachial index (ABI) is a highly sensitive and specific method to diagnose peripheral arterial disease (PAD). Abnormal ABI (≤0.9 or ≥1.4) predicts cardiovascular events and mortality, independent of traditional risk factors. Post-exercise ABIs can identify additional individuals with hemodynamically significant PAD. METHODS: ABI was measured at rest and immediately post-exercise in patients referred for stress testing without known carotid, coronary, or peripheral atherosclerotic disease. ABI was classified as normal (1-1.39), borderline (0.91-0.99), low (≤0.9), or consistent with poorly compressible arteries (≥1.4). Abnormal post-exercise ABI was defined according to guidelines as a ≥20% decrease in ABI or a decline in ankle systolic blood pressure of ≥30 mmHg. ABIs were measured using automated oscillometric cuffs, which correlate well with Doppler and have excellent specificity. RESULTS: 223 patients were enrolled in this ongoing study at the time of analysis, 108 of whom had post-exercise measurements. At rest, 20/223 (9%) had poorly compressible arteries, 7/223 (3.1%) had borderline ABI, and 1/223 (0.5%) had low ABI. Of those with normal ABI for whom post-exercise ABI was obtained, 34/108 (31.5%) had abnormal post-exercise ABI. Among patients with PAD by ABI, rates of use of aspirin (12/35), statins (9/35), and ACE-inhibitor/angiotensin receptor blockers (10/35) were low. Only 2 of 35 patients diagnosed with PAD had abnormal stress tests. 12 of the 223 patients overall had positive stress tests for ischemia. CONCLUSIONS: ABI measurement in patients referred for stress testing led to a diagnosis of peripheral vascular disease (poorly compressible arteries or PAD) in 24.6% of patients, despite low rates of ischemia on clinically indicated stress tests. ABI screening in this patient population may improve our ability to target use of guideline-recommended therapies for the prevention of cardiovascular events.