Rivaroxaban vs. Warfarin for Post Cardiac Surgery Atrial Fibrillation

New onset atrial fibrillation (NOAF) is a common occurrence following cardiac surgery, occurring in 20-30% of patients post-operatively. Historically, Vitamin K antagonist therapy with Warfarin has been the treatment of choice for prophylaxis against stroke and systemic arterial thromboembolism in NOAF. Warfarin inhibits the Vitamin K dependent factors involved in both the intrinsic and extrinsic coagulation cascades, thus decreasing systemic clotting. However, Warfarin therapy comes with many challenges including prolonged titration, tedious monitoring requirements and in some cases, increased bleeding risk. The limitations associated with Warfarin may be mitigated by using new oral anticoagulants (NOACs) like Rivaroxaban which have no routine monitoring requirements. Rivaroxaban is a direct inhibitor of Factor Xa, a central reactant in both the intrinsic and extrinsic coagulation cascades. Studies in non-operative patients with atrial fibrillation have shown that Rivaroxaban is non-inferior to Warfarin for stroke prophylaxis with similar risk profiles. This study aims to compare the efficacy, safety and financial cost of these two drugs when used for the management of new onset atrial fibrillation that occurs after cardiac operations.