Postoperative Atrial Fibrillation and Long-Term Outcomes After Isolated Coronary Artery Bypass Grafting

OBJECTIVES: New-onset postoperative atrial fibrillation is the most common complication after cardiac surgery. This study aimed to evaluate the association between postoperative atrial fibrillation and short-term and long-term clinical outcomes after isolated coronary artery bypass grafting. METHODS: We conducted a retrospective cohort study of adults who underwent isolated coronary artery bypass grafting between 2000 and 2015 at a tertiary care centre. Baseline differences between patients who developed postoperative atrial fibrillation and those who did not were adjusted using inverse probability weighting based on propensity scores derived from demographic, clinical and procedural variables. In-hospital outcomes were analysed using weighted regression models, and long-term all-cause mortality was assessed using weighted Cox proportional hazards regression. RESULTS: Among 5,170 included patients, postoperative atrial fibrillation occurred in 652 (13%). After inverse probability weighting, postoperative atrial fibrillation was associated with a higher risk of perioperative stroke (odds ratio 2.59, 95% confidence interval 1.19-5.64), prolonged mechanical ventilation (odds ratio 1.73, 95% confidence interval 1.22-2.45) and longer hospital stay (mean difference 2.4 days, 95% confidence interval 1.6-3.3). During a median follow-up of 12.8 years, postoperative atrial fibrillation was also associated with higher long-term all-cause mortality (hazard ratio 1.31, 95% confidence interval 1.23-1.51). CONCLUSIONS: In patients undergoing isolated coronary artery bypass grafting, postoperative atrial fibrillation was associated, after inverse probability weighting, with major perioperative complications and reduced long-term survival. These findings suggest that postoperative atrial fibrillation may represent a marker of increased postoperative and long-term risk.