Rivaroxaban vs. Warfarin for Post Cardiac Surgery Atrial Fibrillation
Rivaroxaban vs. Warfarin for Post Cardiac Surgery Atrial Fibrillation
This prospective, randomized, active-controlled, parallel arm study compares the safety and
 financial benefits of arterial thromboembolism prophylaxis with Warfarin vs. Rivaroxaban (A
 novel oral anticoagulant) in patients with new onset atrial fibrillation after sternotomy for
 cardiac operations.
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.
Inclusion Criteria:

 -  Male or Female ≥ 18 years

 -  At least one of the following procedures: coronary artery bypass grafting, aortic
 valve repair, mitral valve repair, non-mechanical aortic valve replacement, any
 combination of these procedures

 -  Two or more episodes of New Onset Atrial Fibrillation (each lasting > 20 minutes) or
 persistent atrial fibrillation lasting > 24 hours (Or for >18 hours over a 24-hour
 interval)

 -  If female of child-bearing age, use of adequate contraception

 Exclusion Criteria:

 -  Pre-existing paroxysmal atrial fibrillation before cardiac surgery

 -  Pre-existing indications for therapeutic anticoagulation (Including but not limited to
 PE, DVT, mechanical valve)

 -  Moderate-to-severe mitral valve stenosis not surgically corrected

 -  Pre-existing allergy to study medications

 -  Recent (< 1 year) or ongoing pregnancy (Urine pregnancy test will be obtained for
 women of child bearing age at the time of enrollment into the study)

 -  Stroke within 1 month prior to surgery or postoperatively prior to initiation of study
 drugs

 -  Postoperative bleeding episode prior to initiation of study drug

 -  Severe dysfunction of another organ system including GFR < 30 ml/min, baseline INR >
 1.7, ileus or other gastrointestinal pathology hindering ability to absorb oral
 medications, and known coagulation pathway deficiencies

 -  Postoperative need for non-aspirin anti-platelet therapy that cannot be discontinued
 when therapeutic anticoagulation is initiated

 -  Patient taking medications with known major interactions with study drugs with no
 therapeutic alternatives)