Thromboembolic and Mortality Risk in Patients with Postoperative Atrial Fibrillation After Coronary Artery Bypass Graft—The TRIP-AF Study

Background/Objectives: Postoperative atrial fibrillation (POAF) is a common complication of coronary artery bypass grafting (CABG) and may recur during cardiac rehabilitation (CR); its long-term prognostic value remains unclear. We evaluated the impact of POAF on a composite endpoint of all-cause mortality and non-fatal stroke after isolated CABG and assessed POAF duration and timing, AF recurrence, and other predictors of adverse outcomes. Methods: This multicentre retrospective study enrolled 1139 patients who underwent CR after isolated CABG between 2011 and 2015 across 17 Italian centres. Clinical and outcome data were obtained from medical records and structured interviews; median follow-up was 5.78 years. Results: POAF occurred in 34.3% of patients and was associated with a higher incidence of the primary composite endpoint of all-cause mortality and non-fatal stroke in univariate analysis (15.4% vs. 10.0%, p = 0.008), particularly when lasting ≥48 h or occurring during both surgery and rehabilitation. However, in multivariate analysis POAF was not an independent predictor; instead, CHA2DS2-VASc score ≥3, reduced left ventricular ejection fraction, elevated urea, history of heart failure, and AF recurrence during follow-up predicted adverse outcomes. Conclusions: POAF reflects early vulnerability but does not independently predict long-term mortality or stroke. Conversely, AF recurrence and CHA2DS2-VASc score retain strong prognostic value, underscoring the need for long-term rhythm monitoring and individualised risk assessment post-CABG.