Incidence and Clinical Impact of Device-Related Thrombus Following Percutaneous Left Atrial Appendage Occlusion: A Meta-Analysis.

Objectives: This study sought to assess the incidence and clinical impact of device related thrombus (DRT) following precautions left atrial appendage occlusion (LAAO).

Background: Device-related thrombus is a known complication of LAAO. However, data on the incidence of DRT and its impact on outcomes are limited.

Methods: The authors performed a meta-analysis of randomized and observational studies to calculate the pooled incidence of DRT and the pooled odds ratio (OR) of ischemic events in patients with DRT and those without DRT.

Results: In the 66 included studies; the incidence of DRT was 351/10, 153 (3.8%, range 0% to 17%, I = 56.8). The diagnosis was made in <90, 90 to 365, and >365 days in 42%, 57%, and 1% of patients, respectively. There was no difference in DRT rates between the AMPLATZER (AMPLATZER, AGA Medical Corporation, Golden Valley, Minnesota) and WATCHMAN (WATCHMAN, Boston Scientific Corporation, Marlborough, Massachusetts) devices (3.6% vs. 3.1%, p = 0.24). In a meta-regression, age, gender, heart failure, diabetes, CHADS-VASc score, previous stroke, and post-LAAO antithrombotic regimen did not explain the heterogeneity in the incidence of DRT. The pooled incidence of ischemic events in studies that compared outcomes of patients with and without DRT (32 studies; n = 7,689) was 13.2% (37 of 280) in patients with DRT and 3.8% (285 of 7,399) in those without DRT (OR: 5.27, 95% confidence interval [CI]: 3.66 to 7.59; p < 0.001, I = 0). In a sensitivity analysis including randomized trials and prospective multicenter registries, the incidence of DRT was 3.7%, and DRT remained associated with higher rates of ischemic events (13.5% vs. 4.4%, OR: 4.15, 95% CI: 2.77 to 6.22; p < 0.001, I = 0).

Conclusions: DRT after LAAO is uncommon (3.8%) but is associated with a 4- to 5-fold increase in ischemic events. Further studies are needed to understand the underlying mechanisms and the optimal surveillance and management of DRT.