Rivaroxaban for Valvular Heart Disease and Atrial Fibrillation - RIVER

Contribution To Literature:

The RIVER trial showed that rivaroxaban is noninferior to warfarin for prevention of thromboembolic events among patients with AF/AFL and a bioprosthetic mitral valve.


The goal of the trial was to assess the safety and efficacy of rivaroxaban compared with warfarin for patients with a bioprosthetic mitral valve and evidence of atrial fibrillation (AF) or flutter (AFL).

Study Design

Patients were randomized in a 1:1 open-label fashion to either rivaroxaban 20 (15 mg daily if creatinine clearance was 30-49) or warfarin with an international normalized ratio (INR) goal of 2-3. Usual care was provided at the discretion of the clinicians.

  • Total number of enrollees: 1,005
  • Duration of follow-up: 1 year
  • Mean patient age: 59.3 years
  • Percentage female: 60.4%

Inclusion criteria:

  • Age ≥18 years
  • AF or AFL
  • Bioprosthetic mitral valve
  • Receiving or planned use of oral anticoagulant (OAC) for thromboembolism prophylaxis >48 hours from mitral valve surgery

Exclusion criteria:

  • Contraindication to rivaroxaban or warfarin
  • Extremely high risk of bleeding
  • Transient postoperative AF
  • Mechanical valves

Other salient features/characteristics:

  • Mean CHA2DS2-VASc score: 2.6
  • Mean HAS-BLED score: 1.6
  • Interval between mitral valve surgery and randomization: <3 months: 18%, 3 months-<1 year: 16.8%, 1-<5 years: 32.2%, ≥5 years: 30.6%

Principal Findings:

The mean time to the primary outcome (death, major adverse cardiac events, major bleeding) for rivaroxaban vs. warfarin was 347.5 vs. 340.1 days (p < 0.0001 for noninferiority, p = 0.1 for superiority).

Secondary outcomes for rivaroxaban vs. warfarin:

  • Cardiovascular death or thromboembolic event: 3.4% vs. 5.1% (hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.35-1.20)
  • Any stroke: 0.6% vs. 2.4% (HR 0.25, 95% CI 0.07-0.88)
  • Valve thrombosis: 1% vs. 0.6%
  • Any bleeding: 13.0% vs. 15.4% (HR 0.83, 95% CI 0.59-1.15)


The results of this trial indicate that rivaroxaban is noninferior to warfarin for prevention of thromboembolic events among patients with AF/AFL and a bioprosthetic mitral valve. All strokes were lower with rivaroxaban.

This is one of the first trials to directly evaluate the role of a direct OAC (DOAC) in patients with mitral valve disease and atrial arrhythmias. Historically, these patients have been treated with warfarin. Although this trial has limitations (open-label design, etc.), these findings are likely to be practice changing. The only caveat is that it is unclear if the mitral valve surgery was for rheumatic heart disease, in particular mitral stenosis, where warfarin is still recommended as the OAC of choice.


Guimarães HP, Lopes RD, de Barros e Silva PG, et al., on behalf of the RIVER Trial Investigators. Rivaroxaban in Patients With Atrial Fibrillation and a Bioprosthetic Mitral Valve. N Engl J Med 2020;Nov 14:[Epub ahead of print].

Presented by Dr. Otavio Berwanger at the American Heart Association Virtual Scientific Sessions, November 14, 2020.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Prevention, Valvular Heart Disease, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias, Cardiac Surgery and VHD, Interventions and Structural Heart Disease

Keywords: AHA20, AHA Annual Scientific Sessions, Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Atrial Flutter, Cardiac Surgical Procedures, Creatinine, Heart Valve Diseases, Heart Valve Prosthesis, Hemorrhage, Mitral Valve Stenosis, Rheumatic Heart Disease, Secondary Prevention, Stroke, Thromboembolism, Warfarin

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