Anticoagulation for Incident Atrial Fibrillation/Flutter Following Surgical Left Atrial Appendage Occlusion and CABG

Surgical left atrial appendage occlusion (sLAAO) reduces stroke in patients with atrial fibrillation (AF), but its benefit in those without pre-existing AF, when performed prophylactically with cardiac surgery, remains unclear. Further, the role of anticoagulation in patients who develop new AF or atrial flutter (AF/AFL) after sLAAO is not well defined. Given that new-onset AF commonly occurs after coronary artery bypass grafting (CABG), we aimed to compare outcomes between anticoagulation and no anticoagulation in patients developing new AF/AFL following CABG-sLAAO.

Using TriNetX, we identified patients with prior CABG-sLAAO who subsequently developed new AF/AFL. Those with pre-existing AF/AFL and those who underwent percutaneous LAAO were excluded. Patients were categorized based on whether they received anticoagulation or not. Propensity score matching (PSM) was used to balance baseline characteristics, achieving a standardized mean difference of <0.1. Outcomes included ischemic stroke, major bleeding (per ISTH criteria), and all-cause mortality.

Out of 549 patients receiving anticoagulation and 1,004 not receiving anticoagulation, we identified 451 well-matched pairs. The mean age was 69 years, with >75% being male and >75% being White. Hypertension and type 2 diabetes were present in approximately 70% and 45% of the patients, respectively. Over 90% of the patients were on aspirin, beta-blockers, and lipid-lowering agents. There was no significant difference in risk of ischemic stroke (9.3% vs. 7.3%; risk ratio [RR] 1.27, 95% confidence interval [CI] 0.82-1.97, p = 0.28) or all-cause mortality (9.6% vs. 11.2%; RR 0.86, 95% CI 0.58-1.26, p = 0.43), but risk of major bleeding was higher with anticoagulation (10.6% vs. 5.2%; RR 2.04, 95% CI 1.15-3.62, p = 0.013).

Among patients developing new AF/AFL after CABG-sLAAO, anticoagulation was not associated with lower risk of stroke or mortality but was linked to significantly greater bleeding risk. These findings suggest a limited incremental benefit of anticoagulation in this population and highlight the need for prospective evaluation.