Left Atrial Appendage Characteristics Assessed with Cardiac Computed Tomography in Patients with Atrial Fibrillation and Severe Mitral Valve Disease.

Purpose: The morphological and functional characteristics and clinical significance of the left atrial appendage (LAA) are well established in patients with non-valvular atrial fibrillation (AF). However, data on the LAA characteristics in patients with mitral valve (MV) disease are limited. This study aimed to identify the LAA characteristics in AF patients with severe MV disease.

Materials and methods: A total of 506 AF patients who underwent cardiac computed tomography (CT) as preoperative evaluations for MV surgery were retrospectively analyzed. The prevalences of different LAA morphologies (cactus, cauliflower, windsock, chicken wing), LAA ostium diameter, LAA volume, and LAA flow stasis or thrombus were assessed. The LAA variables were compared according to the predominant MV dysfunction.

Results: The most common LAA morphology was cactus (n=211, 41.7%), followed by cauliflower (n=143, 28.3%), windsock (n=90, 17.8%), and chicken wing (n=60, 11.9%). The average LAA ostium maximal diameter and LAA volume were 35.3±8.0 mm and 22.1±15.1 mL, respectively. LAA stasis was found in 215 patients (42.5%) and LAA thrombus in 93 patients (18.4%). Patients with mitral stenosis predominance showed significantly smaller LAA volume compared to those with mitral regurgitation predominance (17.8±11.7 mL vs. 26.9±16.8 mL, p<0.001). However, LAA flow stasis [190 (71.7%) vs. 25 (10.4%), p<0.001] and thrombus [89 (33.6%) vs. 4 (1.7%), p<0.001] were remarkably prevalent in these patients.

Conclusion: Due to advanced LAA remodeling in AF patients with severe MV disease, the morphologic distribution of LAA types differs from that established in patients without MV disease.