The impact of race and postoperative atrial fibrillation on operative mortality after elective coronary artery bypass grafting

Black patients are less likely to develop postoperative atrial fibrillation (POAF) following coronary artery bypass grafting (CABG) than whites. However, the influence of race and POAF on operative mortality has not been examined. The objective of this study was to determine the influence of race and POAF on operative mortality after CABG. Patients undergoing elective CABG between 1992 and 2011 were included. Operative mortality was compared between patients with and those without new-onset POAF by race. Relative risk (RR) and 95% confidence intervals (CI) were computed using Poisson (robust variance estimates) and log-binomial regression models. A total of 1215 (23%) patients developed POAF (white n = 1060; black n = 155) following CABG (N = 5387). Operative mortality differed by POAF status within race category (white POAF: adjusted RR = 1.4, 95% CI = 0.86-2.2; black POAF: adjusted RR = 5.0, 95% CI = 1.9-13; P-interaction = 0.0016). Black POAF patients had a 2-fold increased risk of operative death compared with white POAF patients (P-adjusted = 0.052). POAF was observed to be a stronger predictor of operative mortality in black compared with white patients undergoing elective CABG.