Non-Vitamin K Antagonist Oral Anticoagulant vs Warfarin for Post Cardiac Surgery Atrial Fibrillation

Abstract Background Treatment guidelines for non-valvular atrial fibrillation (AF) recommend use of non-vitamin K antagonist oral anticoagulants (NOAC) over warfarin, yet clinical trials excluded individuals with post-cardiac surgery AF. We sought to compare outcomes with NOACs vs. warfarin for new onset post-cardiac surgery AF. Methods We examined 26,522 patients from the Society of Thoracic Surgeons’ database with post-cardiac surgery AF who were discharged on oral anticoagulation from July 2017–December 2018. Three primary outcomes were evaluated including 30-day mortality, major bleeding complications and stroke/transient ischemic attack (TIA). Secondary outcomes included post-operative length of stay (LOS) and 30-day myocardial infarction, venous thromboembolism and pericardial effusion/tamponade. Results 9,769 (36.8%) participants were prescribed NOACs and 16,753 (63.2%) warfarin. In multivariable analysis, there was no association between type of anticoagulant and 30-day major bleeding complications (ORNOAC/warfarin=0.76,95% CI 0.49-1.18), stroke/TIA (ORNOAC/warfarin=0.94,95% CI 0.53-1.67) or mortality (ORNOAC/warfarin=1.08,95% CI 0.80-1.45). Following stratification by renal function or isolated coronary bypass vs. valve surgery, there remained no difference in the primary outcomes. Additionally, there was no difference in 30-day myocardial infarction (ORNOAC/warfarin=1.17,95% CI 0.62-2.22), venous thromboembolism (ORNOAC/warfarin=0.91,95% CI 0.47-1.78) or pericardial effusion/tamponade (ORNOAC/warfarin=1.09,95% CI 0.80-1.47) between the two groups. NOAC therapy was associated with a half-day reduction in post-operative LOS (βNOAC/warfarin=-0.47,95% CI -0.62 to -0.33). Conclusions NOACs are associated with a reduction in post-operative LOS, without excess bleeding or other short-term complications, compared to warfarin. These findings support the broader use of NOACs as a safe alternative to warfarin in patients with post-cardiac surgery AF at elevated stroke risk and acceptable bleeding risk.