Low Ankle-Brachial Index Predicts Cardiovascular Risk After Acute Ischemic Stroke or Transient Ischemic Attack

Abstract

Background and Purpose— A low ankle-brachial blood pressure index (ABI) is an established risk marker for cardiovascular disease and mortality in the general population, but little is known about its prognostic value in individuals with acute ischemic stroke or transient ischemic attack (TIA). Methods— An inception cohort of 204 patients with acute ischemic stroke or TIA was followed up for a mean of 2.3 years. At baseline, patients underwent ABI measurement and were assessed for risk factors, cardiovascular comorbidities, and cervical or intracranial artery stenosis. The association between low ABI (≤0.9) and the risk of the composite outcome of stroke, myocardial infarction, or death was examined by Kaplan-Meier and Cox regression analyses. Results— A low ABI was found in 63 patients (31%) and was associated with older age, current smoking, hypertension, peripheral arterial disease, and cervical or intracranial stenosis. During a total of 453.0 person-years of follow-up, 37 patients experienced outcome events (8.2% per person-year), with a higher outcome rate per person-year in patients with low ABI (12.8% vs 6.3%, P =0.03). In survival analysis adjusted for age and stroke etiology, patients with a low ABI had a 2 times higher risk of stroke, myocardial infarction, or death than those with a normal ABI (hazard ratio=2.2; 95% CI, 1.1 to 4.5). Additional adjustment for risk factors and cardiovascular comorbidities did not attenuate the association. Conclusions— A low ABI independently predicted subsequent cardiovascular risk and mortality in patients with acute stroke or TIA. ABI measurement may help to identify high-risk patients for targeted secondary stroke prevention.