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

Abstract

Background: Treatment guidelines for nonvalvular atrial fibrillation (AF) recommend use of non-vitamin K antagonist oral anticoagulants (NOACs) 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: 30-day mortality, major bleeding complications, and stroke/transient ischemic attack. Secondary outcomes included postoperative length of stay, 30-day myocardial infarction, venous thromboembolism, and pericardial effusion/tamponade.

Results: A total of 9769 (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 (odds ratio [OR]_{NOAC/warfarin} 0.76, 95% confidence interval [CI] 0.49-1.18), stroke/transient ischemic attack (OR_{NOAC/warfarin} 0.94, 95% CI 0.53-1.67) or mortality (OR_{NOAC/warfarin} 1.08, 95% CI 0.80-1.45). After 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 (OR_{NOAC/warfarin} 1.17, 95% CI 0.62-2.22), venous thromboembolism (OR_{NOAC/warfarin} 0.91, 95% CI 0.47-1.78), or pericardial effusion/tamponade (OR_{NOAC/warfarin} 1.09, 95% CI 0.80-1.47) between the 2 groups. NOAC therapy was associated with a half-day reduction in postoperative length of stay (β_{NOAC/warfarin} -0.47, 95% CI -0.62 to -0.33).

Conclusions: NOACs are associated with a reduction in postoperative length of stay, without excess bleeding or other short-term complications, compared with 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.