Abstract
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. 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). 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.