Background The introduction of non-vitamin-K-antagonist oral anticoagulants (NOAC) has shifted the landscape of anticoagulation in the setting of atrial fibrillation (AF), as an alternative to warfarin. Despite extensive evidence for NOACs in non-perioperative and non-valvular AF, there remains little consensus on anticoagulation choice for patients with postoperative atrial fibrillation (POAF) after cardiac surgery.

Methods This retrospective, observational study included 2263 patients who underwent cardiac surgery between 1 March 2016 and 13 January 2023 at a tertiary cardiac centre. Patients with pre-existing AF, valvular AF and transcatheter interventions were excluded. Short- and long-term outcomes were compared between patients who received a NOAC and those who received warfarin for POAF. A Cox regression model was constructed to identify independent predictors for time-to-mortality. Subgroup analysis was performed based on the type of surgery, including CABG-only, aortic valve replacement (AVR)-only, and combined surgery cohorts.

Results Of the 2263 patients, 556 (24.5%) developed POAF. Of those who developed POAF, 162 were anticoagulated with warfarin and 65 were anticoagulated with a NOAC, including apixaban, rivaroxaban and dabigatran. There were three cases of permanent stroke in the warfarin group compared with no cases in the NOAC group. All-cause 30-day and one-year readmission rates were similar between groups. The use of NOAC or warfarin did not impact overall survival in the Kaplan–Meier analysis. Subgroup analysis demonstrated similar outcomes in CABG-only, AVR-only and combined surgery groups.

Conclusions Warfarin and NOAC performed similarly in short- and long-term complications, suggesting NOAC as a plausible alternative to warfarin for anticoagulation in POAF.