Abstract P007: Ankle-brachial Index And Cardiovascular Outcomes In Older Adults: The Atherosclerosis Risk In Communities Study

Abstract

Introduction: The ankle-brachial index (ABI) is a representative diagnostic indicator of peripheral artery disease (PAD) and recognized as a risk enhancer in the ACC/AHA guidelines for primary prevention of atherosclerotic cardiovascular disease (ASCVD). However, our understanding of the association between ABI and cardiovascular (CVD) risk in older adults is limited. Additionally, the prognostic value of ABI among individuals with prior ASCVD is not well understood. Hypothesis: In a contemporary cohort of older adults, low ABI is independently associated with higher risk of CVD events, regardless of prevalent ASCVD at baseline (coronary heart disease [CHD], stroke, and/or symptomatic PAD). Methods: At ARIC Visit 5 (2011-2013), we studied 5,005 participants (4,160 without prior ASCVD [median age 74 years, 38% male], and 843 with ASCVD [median age 76 years, 65% male]). We quantified the association between ABI categories and subsequent risk of heart failure (HF) and composite CHD/stroke using multivariable Cox proportional hazards models. Results: Over a median follow-up of 5.5 years, we observed 400 CHD/stroke and 338 HF cases (242 CHD/stroke and 199 HF cases in those without prior ASCVD). After adjustment for CVD risk factors, in those without ASCVD history, ABI ≤0.9 was associated with a higher risk of both CHD/stroke and HF ( Table ). In those with a history of ASCVD, low ABI was not significantly associated with CHD/stroke, but was associated with HF (hazard ratio 7.1, 95% CI: 2.5-20.5); ABI categories of 0.9-1.1 and >1.3 were also significantly associated with HF. Addition of ABI to traditional risk factors improved prediction of CHD/stroke risk in those without prior ASCVD and prediction of HF, regardless of baseline ASCVD ( Table ). Conclusions: Low ABI (≤0.9) was associated with incident CHD/stroke in those without prior ASCVD and HF regardless of baseline ASCVD status. These results support ABI as a risk enhancer for guiding primary prevention of ASCVD and suggest its potential value in HF risk assessment for older adults.