Abstract W MP56: Left Atrial Septal Pouch as a Stroke Risk Factor: Association With Cryptogenic Stroke

Abstract

Background: The left atrial septal pouch (LASP) is an anatomic variant of the interatrial septum, and its pathophysiological significance is uncertain (J Am Coll Cardiol Intv 2010;3:98-104). We examined the potential association between LASP and ischemic stroke subtypes in patients undergoing transesophageal echocardiography (TEE). Methods: In this cross-sectional study, we determined the prevalence of LASP ( Figure ) using a database of patients who underwent TEE at our institution between July 2008 and June 2011. Patients with ischemic strokes were evaluated by a vascular neurologist (blinded to the presence of LASP) for stroke subtyping using standard and modified TOAST (excluding ischemic stroke patients with multiple competing etiologies from the cryptogenic category) criteria. We compared the prevalence of LASP in ischemic stroke, cryptogenic stroke, and non-stroke patients. Results: The mean age of all 212 patients studied (including stroke and non-stroke patients) was 57 years. The overall prevalence of LASP was 17% (n=35). We studied 75 ischemic stroke patients. There were no significant differences in demographics or stroke risk factors comparing patients with or without LASP, except for hypertension (LASP 49% vs. no LASP 66% among all patients, p = 0.05). The prevalence of LASP among cryptogenic stroke (using standard and modified TOAST criteria) was increased compared to the prevalence among other ischemic stroke patients (26% vs. 9%, RR=1.8, 95% CI 1.1-3.1; and 30% vs. 9%, RR=2.3, 95% CI 1.2-4.1, respectively). There was no significant difference between LASP prevalence among all ischemic stroke patients (16%) and patients with no history of stroke or TIA (14%). Conclusion: In this population of relatively young patients, prevalence of LASP was increased in cryptogenic stroke compared to stroke patients of other subtypes. These findings suggest LASP may be a risk factor for stroke, which should be verified by further large-scale studies.