The association of ankle-brachial index with silent cerebral small vessel disease: Results of the Atahualpa Project

Background: An abnormal ankle-brachial index has been associated with overt stroke and coronary heart disease, but little is known about its relationship with silent cerebral small vessel disease. Aim: To assess the value of ankle-brachial index as a predictor of silent small vessel disease in an Ecuadorian geriatric population. Methods: Stroke-free Atahualpa residents aged ≥60 years were identified during a door-to-door survey. Ankle-brachial index determinations and brain magnetic resonance imaging were performed in consented persons. Ankle-brachial index ≤0·9 and ≥1·4 were proxies of peripheral artery disease and noncompressible arteries, respectively. Using logistic regression models adjusted for age, gender, and cardiovascular health status, we evaluated the association between abnormal ankle-brachial index with silent lacunar infarcts, white matter hyperintensities, and cerebral microbleeds. Results: Mean age of the 224 participants was 70±8 years, 60% were women, and 80% had poor cardiovascular health status. Ankle-brachial index was ≤0·90 in 37 persons and ≥1·4 in 17. Magnetic resonance imaging showed lacunar infarcts in 27 cases, moderate-to-severe white matter hyperintensities in 47, and cerebral microbleeds in 26. Adjusted models showed association of lacunar infarcts with ankle-brachial index≤0·90 (OR: 3·72, 95% CI: 1·35-10·27, P=0·01) and with ankle-brachial index≥1·4 (OR: 3·85, 95% CI: 1·06-14·03, P=0·04). White matter hyperintensities were associated with ankle-brachial index≤0·90 (P=0·03) and ankle-brachial index≥1·4 (P=0·02) in univariate analyses. There was no association between ankle-brachial index groups and cerebral microbleeds. Conclusions: In this population-based study conducted in rural Ecuador, apparently healthy individuals aged ≥60 years with ankle-brachial index values ≤0·90 and ≥1·4 are almost four times more likely to have a silent lacunar infarct. Ankle-brachial index screening might allow recognition of asymptomatic people who need further investigation and preventive therapy.