Abstract TP230: Left Atrial Appendage Volume Is Increased In More Than Half Of Patients With Cryptogenic Stroke

Abstract

Background: Ischemic stroke without a well-defined etiology is labelled as cryptogenic, and it accounts for 30 − 40 % of strokes in modern stroke registries. Enlarged left atrial appendage (LAA) is the most typical origin for intracardiac thrombus formation. We studied whether increased LAA volume detected with cardiac computed tomography (cCT) constitutes a risk factor in cryptogenic stroke patients. Materials and methods: Consecutive stroke or TIA patients with cryptogenic etiology for stroke after profound clinical, radiological and cardiological investigations were selected for the study. The 1993 TOAST criteriae modified by 2010 EAE recommendations for defining cardiac sources of embolism were used for classification. Eighty-two patients (57 males; mean age 58 years) were identified. Forty control subjects without cardiovascular diseases, matched for age and gender, were selected for pair-wise comparisons (21 males; mean age 54 years). LAA volume adjusted for body surface area was measured three dimensionally by tracing the borders of LAA on CT slices. The upper limit for normal LAA volume was defined as mean + 2 SD in control subjects. Results: In control subjects LAA volume was 3.4 ± 1.1 mL/m 2 (range 1.3 − 6.0 mL/m 2 ). The upper limit for normal LAA was 5.6 mL/m 2 . Of the patients with cryptogenic stroke/TIA 45 (55 %) had enlarged LAA. In matched pair-wise comparisons LAA volume was 67 % larger in cryptogenic stroke/TIA patients than in control subjects (5.7 ± 2.0 mL/m 2 vs. 3.4 ± 1.1 mL/m 2 ; P < 0.001). Conclusions: LAA is significantly enlarged in more than half of patients with cryptogenic stroke, and thus do not have atrial fibrillation as a preceding risk factor. LAA thrombosis may contribute in the pathogenesis of stroke in patients considered to have cryptogenic stroke after conventional evaluation.