Abstract T MP101: Association of Obstructive Sleep Apnea and Cardioembolic Stroke: A Retrospective Case Control Study

Abstract

Introduction: Obstructive sleep apnea (OSA) is an independent risk factor for ischemic stroke; however the causal mechanisms are unknown. Understanding etiology of stroke in OSA patients may: (1) aid in ascertaining how OSA exerts its influence in increasing stroke risk, and (2) facilitate tailoring recurrent stroke prevention management strategies in OSA patients. Our study compares stroke subtypes in OSA cases versus controls without significant sleep disordered breathing. Hypothesis: We hypothesized cardioembolic (CE) strokes would occur more frequently in OSA cases than in controls. Methods: Consecutive patients were identified who underwent polysomnography (PSG) at Mayo Clinic and suffered an ischemic stroke within one year after PSG. Patients with an apnea-hypopnea index (AHI) ≤ 10 were classified as controls; AHI > 10 classified as OSA cases. Mechanism of stroke was determined using (1) the Causative Classification System for Ischemic Stroke (CCS) and (2) the phenotype definitions used in the Trial of Org 10172 in Acute Stroke Treatment (TOAST). Information on cardiovascular risk factors, neuroimaging, and echocardiography data were collected on each patient. Results: In 53 total subjects, CE strokes were more common among OSA cases (72% vs 33%, p=0.01). Large artery atherosclerosis and small vessel occlusion strokes were more common in controls. Atrial fibrillation (AF) was more frequent in OSA patients (59% vs 24%, p=0.01). Frequency of CE stroke increased with OSA severity. The association between OSA and CE stroke remained significant after controlling for AF (p=0.03, OR 4.5). Echocardiogram data revealed CE stroke risk factors were more frequent in OSA cases (84% vs 52% p=0.02). There were no significant differences between groups for left ventricular ejection fraction, left atrial volume index, or right ventricular systolic pressure. Conclusions: The results demonstrate a strong association between OSA and CE stroke. In OSA patients presenting with cryptogenic stroke, high clinical suspicion for cardioembolism is warranted. This may lead to consideration of further studies (eg, transesophageal echocardiography, Holter monitoring, or extended cardiac monitoring) to identify cardioembolic risk factors such as paroxysmal AF.