Randomized Ischemic Mitral Evaluation - RIME

Description:

The goal of the trial was to evaluate a strategy of coronary artery bypass grafting (CABG) plus mitral valve repair compared with CABG along among patients with multivessel coronary artery disease and at least moderate functional mitral regurgitation.

Hypothesis:

CABG plus mitral valve repair will improve functional capacity.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Patients with multivessel coronary artery disease and at least moderate functional mitral regurgitation

    Number of screened applicants: 172
    Number of enrollees: 73
    Duration of follow-up: 1 year
    Mean patient age: 71 years
    Percentage female: 26%
    Ejection fraction: 40%
    New York Heart Association (NYHA) class: I-3%, II-65%, III-32%

Exclusions:

  • Severe LV dysfunction (LV ejection fraction <30%)
  • Structural abnormality of the mitral valve
  • Significant aortic valve disease
  • Past or present endocarditis
  • Severe comorbidities
  • NYHA class IV, unstable angina, acute pulmonary edema, cardiogenic shock
  • Previous cardiac surgery

Primary Endpoints:

  • Functional capacity, as measured by peak oxygen consumption

Secondary Endpoints:

  • LV reverse remodeling
  • Mitral regurgitation
  • BNP value

Drug/Procedures Used:

Patients with multivessel coronary artery disease and at least moderate functional mitral regurgitation were randomized to CABG plus mitral valve repair (n = 34) versus CABG alone (n = 39).

Moderate functional mitral regurgitation defined by the following:
- Effective regurgitant orifice area 0.2-0.39 cm2
- Regurgitant volume 30-59 ml/beat
- Regurgitant fraction 30-49%
- Vena contracta width 0.3-0.69 cm

Principal Findings:

Overall, 73 patients were randomized. The mean age was 71 years, 26% were women, mean left ventricular (LV) end-systolic diameter was 4.6 cm, mean LV end-diastolic diameter was 5.7 cm, and mean LV ejection fraction was 40%. In the CABG plus mitral repair group, the mean size of the mitral ring was 28 mm.

The median cardiopulmonary bypass time was 147 minutes in the CABG plus mitral repair group versus 84 minutes in the CABG alone group (p < 0.001), median intubation time was 28 hours versus 17 hours (p = 0.004), median volume of transfused blood was 900 ml versus 153 ml (p = 0.016), and median length of hospital stay was 15 days versus 9 days (p = 0.05), respectively.

The primary outcome, percent change in peak oxygen consumption at 1 year, was 22% in the CABG plus mitral valve repair group versus 5% in the CABG alone group (p < 0.001).

LV reverse remodeling: -28% versus -6% (p = 0.002), mitral regurgitation volume: -80% versus -29% (p = 0.001), B-type natriuretic peptide (BNP): -75% versus -58% (p = 0.003), respectively for CABG plus mitral repair versus CABG alone.

Mortality at 30 days was 3% in each group. One-year survival was 91% versus 95% (p = 0.66), and hospital admission for heart failure was 3% versus 3% (p = 0.62), respectively.

Interpretation:

Among patients with multivessel coronary artery disease and at least moderate mitral regurgitation, CABG plus mitral valve repair improved functional capacity at 1 year. This strategy also improved LV reverse remodeling, mitral regurgitation, and BNP levels. CABG plus mitral valve repair required longer bypass time, greater volume of blood transfusion, longer intubation times, and longer hospital stay. Therefore, future studies are needed to determine the impact of this added surgical technique on clinical outcomes.

References:

Chan KM, Punjabi PP, Flather M, et al., on behalf of the RIME Investigators. Coronary Artery Bypass Surgery With or Without Mitral Valve Annuloplasty in Moderate Functional Ischemic Mitral Regurgitation: Final Results of the Randomized Ischemic Mitral Evaluation (RIME) Trial. Circulation 2012;126:2502-2510.

Presented by Dr. John Chan at the American Heart Association Scientific Sessions, Los Angeles, CA, November 7, 2012.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Atherosclerotic Disease (CAD/PAD), Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Interventions and Coronary Artery Disease, Interventions and Structural Heart Disease, Mitral Regurgitation

Keywords: Coronary Artery Disease, Mitral Valve Insufficiency, Length of Stay, Blood Transfusion, Intubation, Oxygen Consumption, Ventricular Remodeling, Heart Failure, Cardiopulmonary Bypass, Coronary Artery Bypass, Mitral Valve Annuloplasty, Mitral Valve, Natriuretic Peptide, Brain


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