Ankle-Brachial Index and Recurrent Stroke Risk: Meta-Analysis

Abstract

Background and purpose: The ankle-brachial index (ABI) is a fast, cheap, noninvasive indicator of atherosclerotic burden that may also be a predictor of stroke recurrence. In this systematic review and meta-analysis, we sought to explore ABI's merit as a marker for stroke recurrence and vascular risk by synthesizing the data currently available in stroke literature.

Methods: We searched Embase, MEDLINE, and Pubmed databases for prospective cohort studies that included consecutive patients with stroke and transient ischemic attack, measured ABI at baseline, and performed a follow-up assessment at least 12 months after initial stroke or transient ischemic attack. The following end points were chosen for our analysis: recurrent stroke and combined vascular end point (recurrent vascular event or vascular death). Crude risk ratios and adjusted Cox proportional hazard ratios were combined separately using the random-effects model. Study-level characteristics (eg, percent of cohort with a history of hypertension, average cohort age, level of adjustment, and mean follow-up duration) were included as covariates in a metaregression analysis.

Results: We identified 11 studies (5374 patients) that were not significantly heterogeneous. Pooling adjusted hazard ratios showed that low ABI was associated with both an increased hazard of recurrent stroke (hazard ratio, 1.70; 95% confidence interval, 1.10-2.64) and an increased risk of vascular events or vascular death (hazard ratio, 2.22; 95% confidence interval, 1.67-2.97).

Conclusion: Our results confirm the positive association between ABI and stroke recurrence. Further studies are needed to see whether inclusion of ABI will help improve the accuracy of prediction models and management of stroke patients.

Keywords: ankle-brachial index; ischemic attack, transient; regression analysis; risk; stroke.