Anticoagulation in new-onset postoperative atrial fibrillation: An analysis from the Society of Thoracic Surgeons Adult Cardiac Surgery Database

Background: New-onset postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery and is associated with increased long-term stroke and mortality. Anticoagulation has been suggested as a potential therapy, but data on safety and efficacy are scant. Objectives: To determine the association between anticoagulation for POAF and long-term outcomes. Methods: Adult patients with POAF after isolated coronary artery bypass surgery (CABG) were identified through the Society of Thoracic Surgeons Adult Cardiac Surgery Database and linked to the Medicare Database. Propensity-matched analyses were performed for all-cause mortality, stroke, myocardial infarction, and major bleeding for patients discharged with or without anticoagulation. Interaction between anticoagulation and CHA₂DS₂-VASc score was also assessed. Results: Of 38,936 patients, 9861 (25%) were discharged on oral anticoagulation. After propensity score matching, discharge anticoagulation was associated with increased mortality (hazard ratio [HR] 1.16, 95% confidence interval [CI] 1.06–1.26). There was no difference in ischemic stroke between groups (HR 0.97, 95% CI 0.82–1.15), but there was significantly higher bleeding (HR 1.60, 95% CI 1.38–1.85) among those discharged on anticoagulation. Myocardial infarction was lower in the first 30 days for those discharged on anticoagulation, but this effect decreased over time. The incidence of all complications was higher for patients with CHA₂DS₂-VASc scores ≥5 compared to patients with scores of 2–4. Anticoagulation did not appear to benefit either subgroup. Conclusion: Anticoagulation is associated with increased mortality after new-onset POAF following CABG. There was no reduction in ischemic stroke among those discharged on anticoagulation regardless of CHA₂DS₂-VASc score.