Prospective Study of Risk Factors for Postoperative Atrial Fibrillation After Cardiac Surgery

Abstract

Introduction: To examine risk factors for new-onset postoperative atrial fibrillation (POAF) after cardiac surgery.

Methods: Patients enrolled in the Cardiothoracic Surgical Trials Network multicenter, randomized trial of rate control versus rhythm control for POAF were included. Predictors of POAF were determined using multivariable logistic regression.

Results: Among the 2104 patients who were enrolled preoperatively, 695 developed POAF (33.0%). Rates of POAF were 28.1% after isolated coronary artery bypass grafting (CABG), 33.7% after isolated valve repair or replacement, and 47.3% after CABG plus valve repair or replacement. Baseline characteristics associated with an increased risk of POAF identified on multivariable analysis included older age (odds ratio [OR] 1.57; 95% confidence interval [CI] 1.42-1.73, per 10 y), White race or non-Hispanic ethnicity (OR 1.52; CI: 1.11-2.07), history of heart failure (OR 1.55; CI: 1.16-2.08), and history of hypothyroidism (OR 1.42; CI 1.04-1.94). The type of cardiac procedure was associated with an increased risk of POAF with both isolated valve repair or replacement (OR 1.33, CI 1.08-1.64) and combined CABG plus valve repair or replacement (OR 1.64, CI 1.24-2.17) having increased risk of POAF compared to isolated CABG. No preoperative cardiac medication was associated with POAF.

Conclusions: In this prospective cohort of patients, older age, a history of hypothyroidism, a history of heart failure, and valve repair or replacement, with or without CABG, and White non-Hispanic race were associated with an increased risk of POAF.

Keywords: Postoperative atrial fibrillation; Risk factor.

Figure 1.

Rates of postoperative atrial fibrillation across types of cardiac surgery. Abbreviations: CABG: coronary artery bypass grafting.

Figure 2.

Multivariable logistic regression analysis of occurrence of postoperative atrial fibrillation after cardiac surgery. Analysis is adjusted for demographic, clinical, pharmacologic, and procedural covariates including age per 10 years (centered on mean), sex, White race or non-Hispanic ethnicity, body mass index (continuous), diabetes mellitus, hypertension, heart failure, hypothyroidism, and pre-procedure use of diuretics, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and calcium channel blockers. The covariate “non-rheumatic heart disease” was collinear with type of cardiac procedure and is excluded from this analysis. Interactions between all variables were considered and none were found to be significant. Abbreviations: CABG: coronary artery bypass grafting; CI: confidence intervals; OR: Odds Ratio.