Introduction: Postoperative onset atrial fibrillation (POAF) is a common complication of coronary artery bypass surgery (CABG). However, the long-term risk of thromboembolism in patients who develop POAF after CABG surgery is unknown. Also, there is no information about stroke prevention in this setting. To investigate the long-term risk of stroke and thromboembolism in patients with new-onset POAF after initial CABG alone compared with patients with non-functional non-valvular atrial fibrillation (NVAF)

Material and Methods: This study used data from the Clinical Cardiac Surgery Database and the Danish National Registry to identify patients undergoing a primary CABG procedure and de novo CABG between January 1, 2000 and June 30, 2015. The age, sex, CHA2DS2-VASc score and year of diagnosis of these patients were compared with dysfunctional NVAF between 1 and 4. Data analysis was performed between 2012-15. Proportion of patients starting oral anticoagulation within 30 days and thromboembolic rate.

Results: 115 patients who developed POAF after CABG surgery and 115 patients who developed NVAF were compared. In the total population of 10,540 patients, the median (interquartile range) age was 69 years.2 (63.7-74.7) years; 8675 patients (82.3%) were male. 175 POAF patients (8.4% and 3549 patients with NVAF (42.9%). The risk of thromboembolism was lower in the POAF group than in the NVAF group (18.3 vs. 29.7 events per 1000 person-years; adjusted hazard ratio [HR], 0.55; 95% confidence interval, 0.32-0.95; P = .03) and NVAF (adjusted HR, 0.59; 95% CI, 0.68; P < .001) compared with patients not receiving anticoagulant therapy.

Conclusion: Patients undergoing CABG surgery had a longer risk of thromboembolic new POAF than those undergoing NVAF. These data do not support the view that de novo POAF should be considered the same as primary NVAF in terms of long-term thromboembolic risk.