BACKGROUND - Data on the impact of residual peri-device leak after left atrial appendage occlusion (LAAO) are limited.

OBJECTIVES - The goal of this study was to explore the association of peri-device leak with adverse clinical events.

METHODS - The National Cardiovascular Data Registry LAAO Registry was queried to identify patients undergoing LAAO between January 1, 2016, and December 31, 2019. Patients were classified according to leak size on echocardiography at 45 ± 14 days (0 mm, no leak; >0-5 mm, small leak; and >5 mm, large leak).

RESULTS - A total of 51,333 patients were included, of whom 37,696 (73.4%) had no leak, 13,258 (25.8%) had small leaks, and 379 (0.7%) had large leaks. The proportion of patients on warfarin at 45 days was higher in the large vs small or no leak cohorts (44.9% vs 34.4% and 32.4%, respectively; P < 0.001). At 6 and 12 months, anticoagulant utilization decreased but remained more frequent in patients with large leaks. Thromboembolic and bleeding events were uncommon in all groups. However, compared with patients with no leak, those with small leaks had slightly higher odds of stroke/transient ischemic attack/systemic embolization (adjusted HR: 1.152; 95% CI: 1.025-1.294), major bleeding (HR: 1.11; 95% CI: 1.029-1.120), and any major adverse events (HR: 1.102; 95% CI: 1.048-1.160). There were no significant differences in adverse events between patients with large leaks and patients with small or no leaks.

CONCLUSIONS - Small (>0-5 mm) leaks after LAAO were associated with a modestly higher incidence of thromboembolic and bleeding events; large leaks (>5 mm) were not associated with adverse events, although higher proportions of these patients were maintained on anticoagulation. Newer devices with improved seal might mitigate the events associated with residual leaks.