Galectin-3 is an independent predictor of postoperative atrial fibrillation and survival after elective cardiac surgery

Background Postoperative atrial fibrillation (POAF) is a frequent complication after heart surgery and is associated with thromboembolic events, prolonged hospital stay, and adverse outcomes. Inflammation and fibrosis are involved in the pathogenesis of atrial fibrillation. Objective The purpose of this study was to assess whether galectin-3, which reflects preexisting atrial fibrosis, has the potential to predict POAF and mortality after cardiac surgery. Methods Four hundred seventy-five consecutive patients (mean age 67.4 ± 11.8 years; 336 (70.7%) male) undergoing elective heart surgery at the Medical University of Vienna were included in this prospective single-center cohort study. Galectin-3 plasma levels were assessed on the day before surgery. Results The 200 patients (42.1%) who developed POAF had significantly higher galectin-3 levels (9.60 ± 6.83 ng/mL vs 7.10 ± 3.54 ng/mL; P < .001). Galectin-3 significantly predicted POAF in multivariable logistic regression analysis (adjusted odds ratio per 1-SD increase 1.44; 95% confidence interval 1.15–1.81; P = .002). During a median follow-up of 4.3 years (interquartile range 3.4–5.4 years), 72 patients (15.2%) died. Galectin-3 predicted all-cause mortality in multivariable Cox regression analysis (adjusted hazard ratio per 1-SD increase 1.56; 95% confidence interval 1.16–2.09; P = .003). Patients with the highest-risk galectin-3 levels according to classification and regression tree analysis (>11.70 ng/mL) had a 3.3-fold higher risk of developing POAF and a 4.4-fold higher risk of dying than did patients with the lowest-risk levels (≤5.82 ng/mL). Conclusion The profibrotic biomarker galectin-3 is an independent predictor of POAF and mortality after cardiac surgery. This finding highlights the role of the underlying arrhythmogenic substrate in the genesis of POAF. Galectin-3 may help to identify patients at risk of POAF and adverse outcome after cardiac surgery.