Associations of ankle-brachial index (ABI) with cerebral arterial disease and vascular events following ischemic stroke

Abstract

Objectives: Low ankle-brachial index (ABI), indicative of peripheral arterial disease (PAD), is a risk factor for stroke. ABI has been shown to be associated with cerebral arterial disease and prognosis following stroke. We studied the associations of the degree of ABI lowering with extracranial carotid disease (ECD), intracranial large artery disease (ICLAD), and subsequent vascular events in a prospective cohort of acute ischemic stroke patients.

Methods: ABI, extracranial and intracranial cerebral arteries were assessed in a blinded manner. ABI was categorized into 0.9-1.3 (normal), 0.8-0.89 (mildly lowered) and <0.8 (severely lowered). Follow-up data at 1 year were obtained from standardized telephone interviews and verified with medical records.

Results: Among the 1311 patients, 73% had normal ABI, 13% had ABI 0.8-0.89 and 13% had ABI <0.8. Compared to patients with normal ABI, those with ABI<0.8 had higher prevalence of severe ECD (15% vs. 5%, p = 0.006) and ICLAD (72% vs. 48%, p = 0.003), even after adjustment for age, gender, hypertension, diabetes, hyperlipidemia, smoking, ischemic heart disease and atrial fibrillation (severe ECD p < 0.001, ICLAD p < 0.001). At 1 year, patients with ABI <0.8 had a higher incidence of composite vascular events (19% vs. 11%, p = 0.02), stroke (15% vs. 10%, p = 0.06) and myocardial infarction (4% vs. 2%, p = 0.07) than patients with normal ABI.

Conclusion: Among ischemic stroke patients, large cerebral arterial disease and incidence of subsequent vascular events at 1 year were associated with severe ABI lowering <0.8, but not with mild ABI lowering (0.8-0.89).