Bleeding risk assessment in patients with new-onset atrial fibrillation after coronary surgery: A proof-of-concept study

AIMS: Current guidelines recommend considering long-term oral anticoagulation in patients with new-onset postoperative atrial fibrillation (POAF) after cardiac surgery, balancing stroke and bleeding risk. However, no specific approach to bleeding risk assessment is provided. We explored in a proof-of-concept study whether a bleeding risk score can identify patients with POAF after coronary artery bypass grafting (CABG) with increased risk of post-discharge major bleeding. METHODS AND RESULTS: This observational cohort study included 4436 patients with POAF after CABG in 2009-2020 without oral anticoagulation. The four-item PRECISE-DAPT score (based on age, creatinine clearance, preoperative hemoglobin concentration, and previous bleeding) was calculated for all patients. Bleeding risk was defined as high (≥25 points), medium (16-24 points), or low (≤15 points). Associations between bleeding risk and major bleeding events during the first postoperative year were assessed by Cox regression. Discrimination was evaluated with C-statistics, and calibration by comparing expected and observed bleeding rates. Major bleeding occurred in 2.1% of patients during the first year. The score classified 36.0% of patients as high bleeding risk. The hazard ratio for high versus low bleeding risk was 4.81 (95% CI 2.59-8.96). The area under the receiver operating characteristic curve was 0.68 (95% CI 0.63-0.73). Calibration showed good agreement between expected and observed bleeding events in patients with an annual bleeding risk up to 7%. CONCLUSIONS: A bleeding risk score can be used to stratify patients with POAF after CABG into groups with different post-discharge bleeding risk. Further studies are necessary to identify the optimal risk score and its role in OAC decision pathway to improve clinical outcomes.