Atrial appendage closure is associated with increased risk for postoperative atrial fibrillation.

Objectives: This study aims to examine the relationship between left atrial appendage closure (LAAC) and post-operative atrial fibrillation (POAF) in cardiac surgery patients with no pre-operative atrial fibrillation (AF).

Methods: We analyzed a cohort of 2059 adult patients in our Society of Thoracic Surgery (STS) database who underwent at least one of the following procedures between 2018 and 2021: coronary artery bypass grafting (CABG), aortic valve replacement, or mitral valve replacement. All patients had no pre-operative AF, and 169 (8.2%) of them received a left atrial appendage closure (LAAC). Primary outcome was new-onset POAF and secondary outcomes included 1-year mortality, 30-day readmission, 1-year incident stroke, and post-operative hospital length of stay (LOS). Patients without an LAAC were matched to patients with LAAC using a 1:1 nearest neighbor propensity score method to reduce the bias due to potential confounding. Associations between LAAC and postoperative adverse outcomes were assessed using appropriate statistical tests for matched analyses.

Results: The matched cohort included 162 pairs. LAAC was associated with elevated risk of new-onset POAF (41.4% vs. 25.3%, p = 0.003), and postoperative hospital LOS (142.1 vs. 120.5 h, p = 0.001). The LAAC did not significantly impact all-cause 1-year mortality, 30-day readmission, and 1-year incident stroke.

Conclusions: In cardiac surgery patients with no pre-operative history AF, LAAC was associated with substantially higher rates of new-onset POAF, without a corresponding impact on risk of 1-year incident stroke, 30-day readmission, or 1-year mortality.