Outcomes of Different Device Sizing Strategies Using the Newer-Generation WATCHMAN Devices for Closure of Borderline-Sized Left Atrial Appendage.

BACKGROUND

In left atrial appendage closure (LAAC) using newer-generation WATCHMAN FLX/FLX Pro devices, managing borderline-sized LAA within overlapping zones is common, but optimal device sizing strategies remain unknown.

AIMS: To compare clinical outcomes and device-related complications between smaller and larger device sizing strategies for borderline-sized LAA.

METHODS

This single-center retrospective study evaluated 91 patients undergoing newer-generation WATCHMAN implantation for borderline-sized LAA between September 2021 and June 2024. Follow-up imaging (transesophageal echocardiography and/or cardiac computed tomography angiography) was performed 45-120 days post-LAAC, and one-year clinical outcomes were assessed.

RESULTS

Patients were divided into smaller (n = 36) and larger (n = 55) device groups. The composite primary endpoint (cardiovascular mortality and ischemic stroke) was similar between groups (8.3% vs. 3.6%; hazard ratio [HR], 0.372; 95% CI: 0.074-2.650, p = 0.334). However, the secondary efficacy endpoint-peridevice leak (PDL) 〉3 mm and/or device-related thrombus (DRT)-was significantly higher in the smaller device group at initial follow-up, even after covariate adjustment (13.9% vs. 1.8%; HR, 0.091; 95% CI: 0.009-0.887, p = 0.039). Similar findings were observed at one year.

CONCLUSION

For borderline-sized LAA treated with newer-generation WATCHMAN devices, smaller and larger sizing strategies yielded similar one-year clinical outcomes. However, the larger device strategy showed a lower incidence of PDL >3 mm and/or DRT.