Abstract 4136632: Impact of Postoperative Atrial Fibrillation on Long-term Clinical Outcomes in Patients after Coronary Artery Bypass Grafting

Background: The impact of postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG) on long-term clinical outcomes has not been adequately evaluated yet. Methods: Among consecutive 14927 patients who underwent their first coronary revascularization in the CREDO-Kyoto PCI/CABG Registry Cohort-3 (2011-2013), the study population consisted of 1483 patients who underwent CABG after excluding those with prior AF. POAF was defined as newly documented AF during hospitalization for CABG. The primary outcome measure was all-cause death after discharge. The median clinical follow-up was 5.7 (interquartile range, 4.4-6.6) years. Results: POAF was observed in 337 patients (23%). Multivariable logistic regression analysis indicated that age >=75 years (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.24-2.10; P<0.001) and cardiopulmonary bypass (CPB) use (OR, 1.40; 95%CI, 1.09-1.79; P=0.01) were independent predictors of POAF. Of the 1400 patients discharged alive among the study population, the POAF group included more older patients, patients with prior stroke, and patients prescribed beta-blockers and oral anticoagulants than the non-POAF group. The cumulative 5-year incidence of all-cause death was 15.9% in the POAF group and 13.0% in the non-POAF group (Log-rank P=0.38). After adjusting for confounders, the adjusted risk for all-cause death was almost neutral (adjusted HR, 0.96; 95%CI, 0.70-1.31; P=0.81). The cumulative 5-year incidence of stroke was significantly higher in the POAF group than in the non-POAF group (8.0% versus 4.2%; Log-rank P=0.02), and the adjusted risk of stroke in the POAF group relative to the non-POAF group tended to be higher (adjusted HR: 1.58, 95%CI, 0.99-2.53; P=0.057). However, the cumulative 5-year incidence of major bleeding was significantly higher in the POAF group than in the non-POAF group (14.6% versus 10.7%; Log-rank P=0.01). Even after adjusting for confounders, the excess risk of major bleeding in the POAF group was significant (adjusted HR, 1.42; 95%CI, 1.01-2.00; P=0.041). Conclusions: Advanced age and CPB use were associated with POAF occurrence. POAF was not associated with long-term mortality after discharge. However, it tended to be associated with a higher risk for stroke and was associated with a significantly higher risk for major bleeding. Further study would be needed to clarify the appropriate management of POAF after CABG.