Abstract 18311: Low and Borderline Ankle Brachial Index Are Associated With Intracranial Aneurysms - A Retrospective Cohort Study

Abstract

Background: A low ankle-brachial index (ABI) is associated with a higher risk of cardiovascular diseases, stroke, and systemic inflammation. Intracranial aneurysms (IAs) share similar risk factors with other cardiovascular diseases. However, there is a lack of studies that investigate the association between low ABI and IAs. Aims: To study whether low, borderline, or high ABI is associated with an increased risk of IAs compared to a normal ABI. Methods: We conducted a retrospective review of all patients (n=2751) who had ABI measurements at our tertiary hospital between 2011 and 2013. Patients with available cerebrovascular imaging or a diagnosis of a ruptured IA were included in the study (n=776) to examine the association between ABI and saccular IAs. The patients were classified into four groups as follows: low ABI (≤0.9, n=464), borderline ABI (0.91-0.99, n=47), high ABI (>1.4, n=56), and normal ABI (1.00-1.40, n=209). Results: The prevalence of IAs was 20.3% (18.1% unruptured IAs) in the low ABI group, 14.9% (12.8% unruptured IAs) in the borderline ABI group, 7.0% (5.3% unruptured IAs) in the high ABI group, and 2.4% (1.9% unruptured IAs) in the normal ABI group (p <0.001). In the multinomial regression, which included clinically relevant variables, low ABI (odds ratio [OR], 11.3; 95% confidence interval [CI], 4.1-31.5; p < 0.001) and borderline ABI (OR, 7.1; 95% CI, 1.9-26.6; p <0.001) were the only variables significantly associated with unruptured IAs. Conclusions: Patients with low ABI and borderline ABI had a higher prevalence of IAs compared to patients with a normal ABI. The prevalence of IAs was almost 9-fold higher in the low ABI group and nearly 7-fold higher in the borderline ABI group when compared to the normal ABI group.