Risk Stratification for Pericardial Effusion After Leadless Pacemaker Implantation - Multicenter Study.

Background: Postoperative pericardial effusion (PPE) is a known complication associated with the use of leadless pacemakers (LPMs). The risk score (RS) is a useful tool for risk stratification. This study evaluated the utility of risk stratification using the RS in Japanese patients who received the Micra LPM.

Methods and results: We retrospectively enrolled 443 patients who received Micra LPMs that were implanted at 4 institutions between August 2017 and August 2024. Patients were risk stratified using the RS into 3 groups: low risk (score ≤0), intermediate risk (score 1), and high risk (score ≥2). PPEs were observed in 9.0% (20/221), 11.7% (9/77) and 17.9% (26/145) of patients in the low-, intermediate-, and high-risk groups, respectively (P=0.041). In multivariable analysis, chronic obstructive pulmonary disease was a significant risk factor (P=0.014) for PPE, whereas prior cardiac surgery significantly reduced the risk of PPE (P=0.023). Older age, being female, and hemodialysis were not identified as risk factors. Subsequently, we modified the RS (mRS). Using the mRS, PPEs were observed in 8.8% (27/306), 16.5% (14/85), and 26.9% (14/52) of patients in the low-, intermediate-, and high-risk groups, respectively (P<0.001).

Conclusions: The original RS is useful for PPE risk stratification after Micra LPM implantation. However, the mRS provides better risk discrimination and may therefore be a more suitable tool for use in the Japanese population.