Factors associated with postoperative atrial fibrillation and other adverse events after cardiac surgery

Abstract

Objective: The study objective was to evaluate the impact of various surgical characteristics and practices on the risk of postoperative atrial fibrillation and other adverse outcomes after cardiac surgery.

Methods: By using the prospectively collected data of patients who underwent cardiac surgery in 28 centers across the United States, Italy, and Argentina, the details of surgery characteristics were collected for each patient and the outcomes, including postoperative atrial fibrillation, major adverse cardiovascular events, and mortality. These were evaluated via multivariable-adjusted models.

Results: In 1462 patients, a total of 460 cases of postoperative atrial fibrillation, 33 major adverse cardiovascular events, 23 cases of 30-day mortality, and 46 cases of 1-year mortality occurred. We found that type of surgery and cardiopulmonary bypass use predicted the occurrence of postoperative atrial fibrillation. Compared with coronary artery bypass grafting alone, there was a higher risk of postoperative atrial fibrillation with valvular surgery alone (odds ratio, 1.4; 95% confidence interval, 1.1-1.9), and the risk was even higher with concomitant valvular and coronary artery bypass grafting surgery (odds ratio, 1.8; 95% confidence interval, 1.2-2.7). Compared with no bypass, use of cardiopulmonary bypass was associated with higher risk of postoperative atrial fibrillation (odds ratio, 2.4; 95% confidence interval, 1.7-3.5), but there were significant age and sex differences of the impact of bypass use among patients undergoing coronary artery bypass grafting (P for interaction = .04). In addition, compared with spontaneous return of rhythm, ventricular pacing was associated with a higher risk of major adverse cardiovascular events (odds ratio, 5.0; 95% confidence interval, 1.4-18), whereas concomitant coronary artery bypass grafting and valvular surgery was associated with a higher risk of 30-day mortality (hazard ratio, 4.3; 95% confidence interval, 1.2-14) compared with coronary artery bypass grafting alone. Occurrence of postoperative atrial fibrillation was associated with greater length of stay and 1-year mortality (hazard ratio, 2.2; 95% confidence interval, 1.2-3.9).

Conclusions: In this multicenter trial, we identified specific adverse outcomes that are associated with concomitant valvular and coronary artery bypass graft surgery, cardiopulmonary bypass, ventricular pacing, and occurrence of postoperative atrial fibrillation.

Keywords: adverse cardiovascular event; atrial fibrillation; cardiac surgery; mortality.