Compared with matched controls, patients with postoperative atrial fibrillation (POAF) have increased long-term AF after CABG, and POAF is further associated with increased ischemic stroke, heart failure and mortality even after adjustment for AF

Abstract

Abstract Objective To analyze (1) associations between postoperative atrial fibrillation (POAF) after CABG and long-term cardiovascular outcome, (2) whether associations were influenced by AF during follow-up, and (3) if morbidities associated with POAF contribute to mortality. Methods An observational cohort study of 7145 in-hospital survivors after isolated CABG (1996–2012), with preoperative sinus rhythm and without AF history. Incidence of AF was compared with matched controls. Time-updated covariates were used to adjust for POAF-related morbidities during follow-up, including AF. Results Thirty-one percent of patients developed POAF. Median follow-up was 9.8 years. POAF patients had increased AF compared with matched controls (HR 3.03; 95% CI 2.66–3.49), while AF occurrence in non-POAF patients was similar to controls (1.00; 0.89–1.13). The observed AF increase among POAF patients compared with controls persisted over time (> 10 years 2.73; 2.13–3.51). Conversely, the non-POAF cohort showed no AF increase beyond the first postoperative year. Further, POAF was associated with long-term AF (adjusted HR 3.20; 95% CI 2.73–3.76), ischemic stroke (1.23; 1.06–1.42), heart failure (1.44; 1.27–1.63), overall mortality (1.21; 1.11–1.32), cardiac mortality (1.35; 1.18–1.54), and cerebrovascular mortality (1.54; 1.17–2.02). These associations remained after adjustment for AF during follow-up. Adjustment for other POAF-associated morbidities weakened the association between POAF and overall mortality, which became non-significant. Conclusions Patients with POAF after CABG had three times the incidence of long-term AF compared with both non-POAF patients and matched controls. POAF was associated with long-term ischemic stroke, heart failure, and corresponding mortality even after adjustment for AF during follow-up. The increased overall mortality was partly explained by morbidities associated with POAF. Graphic abstract