Thromboembolic Risk in AF After CABG

Study Questions:

What is the risk of thromboembolism in patients with new-onset postoperative atrial fibrillation (AF) after a first-time isolated coronary artery bypass graft (CABG) surgery?


The authors performed a cohort study from a Danish nationwide registry to identify patients undergoing a first CABG surgery with postoperative AF between 2000 and 2015. These patients were matched to patients with nonsurgical nonvalvular AF. The main outcomes were the proportion of patients initiated on anticoagulation and the rate of thromboembolism.


A total of 2,108 patients with postoperative AF following CABG surgery were matched with 8,432 patients with nonvalvular AF. Oral anticoagulation was initiated within 30 days in 175 (8.4%) postoperative AF CABG patients as compared to 3,549 (42.9%) nonsurgical AF patients. The risk of thromboembolism was lower in the postoperative AF group than the nonsurgical group (18.3 vs. 29.7 events per 1,000 person-years; adjusted hazard ratio [aHR], 0.67; 95% confidence interval [CI], 0.55-0.81; p < 0.001). Anticoagulation therapy during follow-up was associated with a lower risk of thromboembolic events in both postoperative AF patients (aHR, 0.55; 95% CI, 0.32-0.95; p = 0.03) and nonsurgical AF patients (aHR, 0.59; 95% CI, 0.51-0.68; p < 0.001) as compared to nonanticoagulated patients.


The authors concluded that new-onset postoperative AF in first-time CABG patients was associated with a lower long-term thromboembolic risk than patients with nonsurgical AF.


Given the high prevalence of postoperative AF following CABG (11-40%), clinicians must decide if the benefit of long-term anticoagulation for thromboembolism prevention outweighs the bleeding risk. This study suggests that for most patients, long-term anticoagulation is likely not necessary for postoperative AF following CABG surgery. However, patients who remain in AF likely require anticoagulation therapy. Further studies are needed to determine how best to use moderate to long-term event monitors to determine which patients with postoperative AF do require long-term anticoagulation.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias

Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Cardiac Surgical Procedures, Coronary Artery Bypass, Hemorrhage, Risk, Secondary Prevention, Thromboembolism, Vascular Diseases

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