Postoperative atrial fibrillation predicts cause-specific late mortality after coronary surgery

Abstract

Objectives. To investigate the association between postoperative atrial fibrillation (POAF) and cause-specific death after coronary artery bypass grafting (CABG) over time. Design. The cohort included 6821 patients undergoing primary isolated CABG between 1996 and 2009. Survival analyses using Cox proportional hazards determined the association between POAF and late mortality and cause of death. Four categories of mortality were examined: cardiac mortality; and death related to arrhythmia, cerebrovascular disease, and heart failure. Results. Median follow-up was 9.8 years and 2152 of 6821 patients (32%) developed POAF. During follow-up, 2302 of 6821 patients (34%) died. For all mortality categories, lower survival rates were found among POAF patients. After adjustment for baseline characteristics, medical history, and preoperative status, POAF was related to increased mortality in all four categories: cardiac mortality (HR 1.4; 95% CI 1.3–1.5); death related to arrhythmia (HR 1.8; 95% CI 1.6–2.0); cerebrovascular disease (HR 1.4; 95% CI 1.2–1.6); and heart failure (HR 1.4; 95% CI 1.3–1.6). The effect remained more than 8 years after surgery. Conclusions. POAF predicts cause-specific late mortality after CABG, with a sustained effect many years postoperatively. This suggests that POAF-episodes are not merely an indication of more advanced disease at surgery, but predicts a persistent negative effect on cause-specific survival.