Anatomical characteristics of the left atrial appendage in cardiogenic stroke with low CHADS2 scores.

BACKGROUND: Strokes develop even in patients with low CHADS2 scores, and the left atrial appendage (LAA) is the embolic source 90% of the time. We focused on the LAA morphology as a new predictor of strokes. OBJECTIVE: To clarify the anatomical characteristics of the LAA for risk stratification of strokes in patients with nonvalvular atrial fibrillation (AF) who have low CHADS2 scores. METHODS: Among 80 patients who underwent catheter ablation of AF with contrast-enhanced computed tomography, the LAA characteristics were compared between 30 patients with histories of strokes and 50 age-matched controls. The LAA anatomy was classified into 4 types--"cactus," "cauliflower," "chicken wing," and "windsock"--discriminated by the computed tomography measurements of the length, angle, and number of lobes of the LAA. RESULTS: The average CHADS2 score did not differ significantly between patients with stroke and controls (0.8 ± 0.8 vs 0.6 ± 0.7; P = .277). Eight (26.7%) patients with stroke had CHA2DS2-VASc scores of 0. The left atrial size, LAA flow velocity, left ventricular function, and serum brain natriuretic peptide level were also unable to predict strokes. However, a "cauliflower" LAA, defined as a main lobe of less than 4 cm long without forked lobes, was significantly more common in patients with stroke (odds ratio 3.857; 95% confidence interval 1.482-10.037; P = .005). The CHA2DS2-VASc score-adjusted logistic regression analysis revealed the cauliflower LAA as an independent predictor of a stroke (odds ratio 3.355; 95% confidence interval 1.243-9.055; P = .017). CONCLUSIONS: The LAA anatomy might be useful for predicting strokes in patients with nonvalvular AF who have low CHADS2 scores.