Association Between Ischemic Stroke and Left Atrial Appendage Morphology in Patients With Atrial Fibrillation and Low CHA2DS2-VASc Scores

Background Patients with atrial fibrillation are at risk for ischemic stroke, even with low CHA2DS2-VASc scores. The left atrial appendage is a known site of thrombus formation in individuals with atrial fibrillation. Methods We conducted a prospective study, enrolling patients with nonvalvular atrial fibrillation and CHA2DS2-VASc scores of 0 or 1. Patients were divided into groups based on left atrial appendage morphology (determined by computed tomography): the “chicken wing” group and the non–chicken wing group. We followed patients for more than 1 year to observe the incidence of stroke. Results Of 509 patients with a mean (SD) age of 48.9 (11.6) years; 332 (65.2%) were men. The chicken wing group had fewer left atrial appendage lobes, a lower left atrial appendage depth, and a smaller left atrial appendage orifice area (all P < .001). During the follow-up period, 5 of the 133 patients (3.8%) in the chicken wing group and 56 of the 376 patients (14.9%) in the non–chicken wing group experienced ischemic stroke (P < .001). The following findings were significantly associated with the incidence of stroke: left atrial appendage depth (hazard ratio [HR], 1.98; 95% CI, 1.67-3.12; P = .03), left atrial appendage orifice area (HR, 2.16; 95% CI, 1.59–3.13; P < .001), and non–chicken wing left atrial appendage morphology (HR, 1.16; 95% CI, 1.10–1.23; P < .001). Conclusion For patients with atrial fibrillation and a low CHA2DS2-VASc score, the non–chicken wing left atrial appendage morphology type is independently associated with ischemic stroke.