Ankle-brachial index long-term outcome after first-ever ischaemic stroke

Abstract

Background and purpose: Ankle-brachial blood pressure index (ABI) is a clinical tool to identify the presence of peripheral artery disease. There is a scarcity of data associating ABI with long-term outcome in patients with IS. The association between ABI and long-term outcome in patients with first-ever acute IS was assessed.

Methods: Ankle-brachial blood pressure index was assessed in all consecutive patients with a first-ever acute IS admitted at Alexandra University hospital (Athens, Greece) between January 2005 and December 2010. ABI was considered normal when > 0.90 and ≤ 1.30. The Kaplan-Meier product limit method was used to estimate the probability of 5-year composite cardiovascular event-free (defined as recurrent stroke, myocardial infarction or cardiovascular death) and overall survival. A multivariate analysis was performed to assess whether ABI is an independent predictor of 5-year mortality and dependence.

Results: Amongst 653 patients, 129 (19.8%) with ABI ≤ 0.9 were identified. Five-year cumulative composite cardiovascular event-free and overall survival rates were better in normal ABI stroke patients (log-rank test: 7.22, P = 0.007 and 23.40, P < 0.001, respectively). There was no difference in 5-year risk of stroke recurrence between low and normal ABI groups (hazard ratio, HR = 1.23, 95% CI 0.68-2.23). In multivariate Cox regression analysis, independent predictors of 5-year mortality included age (HR = 2.55 per 10 years, 95% CI 1.86-3.48, P < 0.001), the National Institutes of Health Stroke Scale (per point increase HR = 1.12, 95% CI 1.08-1.16, P < 0.001), and low ABI (HR = 2.22, 95% CI 1.22-4.03, P = 0.009). Age (HR = 1.21 per 10 years, 95% CI 1.01-1.45, P = 0.04) and low ABI (HR = 1.72, 95% CI 1.11-2.67, P = 0.01) were independent predictors of the composite cardiovascular end-point.

Conclusions: Low ABI in patients with acute IS is associated with increased 5-year cardiovascular event risk and mortality. However, ABI does not appear to predict long-term stroke recurrence.

Keywords: ankle-brachial index; functional disability; ischemic stroke (IS); mortality; outcome.