Left Atrial Appendage Morphology Assessment for Risk Stratification of Embolic Stroke in Patients with Atrial Fibrillation: A Meta-analysis

Background: Thromboembolic event (TE) risk stratification is performed by using CHA2DS2VASc score. It has been suggested that left atrial appendage (LAA) morphology independently influences TE risk in patients with nonvalvular atrial fibrillation. LAA morphology has been classified into 4 types: chicken wing, cauliflower, windsock, and cactus.

Objective: The purpose of this study was to determine TE risk for each LAA morphology in patients with atrial fibrillation with low to intermediate TE risk.

Methods: A systematic review of MEDLINE, Cochrane Library, and Embase for studies that used computed tomography, tridimensional transesophageal echocardiography, and cardiac magnetic resonance imaging to categorize the LAA morphologies with assessment of TE prevalence. Odds ratio (OR) and 95% confidence intervals (CIs) were measured using the Mantel-Haenszel method. The fixed effects model was used, and if heterogeneity (I2) was >25%, effects were analyzed using a random model.

Results: Eight studies with 2596 patients were included. Eighty-four percent (n=1872) of patients had a CHADS2 score of <2. TE risk was lower in chicken wing morphology than in non-chicken wing morphology (OR 0.46; 95% CI 0.36-0.58). Likewise, chicken wing morphology had lower TE risk than did other morphologies (chicken wing vs cauliflower: OR 0.38; 95% CI 0.26-0.56; chicken wing vs windsock: OR 0.48; 95% CI 0.31-0.73; chicken wing vs cactus: OR 0.49; 95% CI 0.36-0.66).

Conclusion: Patients with chicken wing LAA morphology are less likely to develop TE than patients with non-chicken wing morphology. LAA morphology may be a valuable criterion in predicting TE and could affect the stratification and anticoagulation management of patients with low to intermediate TE risk.