Ankle—Brachial Index: A Marker of Both Peripheral Arterial Disease and Systemic Atherosclerosis As Well As a Predictor of Vascular Events

Abstract

Signorelli et al in this issue of Angiology screened almost 3500 asymptomatic individuals (mean age 61.3 + 9.7 years) using the ankle brachial index (ABI) to detect unrecognized peripheral arterial disease (PAD). An ABI 0.9 was considered diagnostic. A total of 80 (2.3%) participants had unrecognized PAD. Of interest, among those individuals with unrecognized PAD, 5% (n 1⁄4 4) also had >75% asymptomatic carotid artery stenosis, whereas 12.5% (n 1⁄4 8) had an ejection fraction 30% asymptomatic carotid artery stenosis. In multivariate analysis, an ABI 50% stenosis, whereas 2.7% had an occluded internal carotid artery. An ABI 3-fold increased risk for >50% carotid stenosis compared with individuals with an ABI >0.9 (odds ratio [OR], 3.37; 95% CI, 1.04-10.93; P 1⁄4 .033). An ABI <0.9 in patients with asymptomatic PAD is not only a marker of generalized atherosclerosis but also a predictor of perioperative myocardial damage, should these patients undergo vascular surgery for an unrelated condition. The ABI was recorded in 627 consecutive patients undergoing carotid endarterectomy or abdominal aortic aneurysm repair. In multivariate analysis, an asymptomatic ABI <0.9 was associated with a 2.4-fold increased risk of perioperative myocardial damage (OR, 2.4; 95% CI, 1.4-4.2). Besides the ABI, several other markers/tests may reflect the presence of PAD. Examples include C-reactive protein (CRP) and functional photoplethysmograph technology using a noninvasive automated device. Both have the advantage that, unlike the ABI, they are less operator-dependent. Future studies should evaluate the prognostic significance of these variables in patients with PAD as well as their ability to identify unrecognized PAD. The identification of subclinical PAD holds implications for the timely initiation of preventive measures, namely smoking cessation, weight reduction, adoption of exercise, blood pressure and diabetes mellitus control, management of dyslipidemia, and antiplatelet treatment. Patients with PAD need to be closely monitored. The early diagnosis of PAD and the initiation of conservative measures is associated not only with a reduction in disease progression but also with several additional beneficial actions. For example, PAD is associated with the metabolic syndrome which requires treatment in its own right. Besides the management of dyslipidemia, routine statin treatment in patients with PAD is associated with an improvement in claudication, increased walking distance, and