Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation - COAPT

Contribution To Literature:

The COAPT trial showed that transcatheter mitral valve approximation using the MitraClip on a background of maximally tolerated GDMT was superior to GDMT alone in reducing HF hospitalization and mortality in symptomatic HF patients with grade 3-4+ MR.

Description:

The goal of the trial was to assess the safety and efficacy of transcatheter mitral leaflet approximation using MitraClip among symptomatic heart failure (HF) patients with secondary mitral regurgitation (MR).



Study Design

Patients with HF and grade 3-4+ MR who remained symptomatic despite maximally tolerated guideline-directed medical therapy (GDMT) were randomized to MitraClip + GDMT (n = 302) vs. GDMT alone (n = 312). This trial had an open-label design.

  • Total number of enrollees: 614
  • Duration of follow-up: 24 months
  • Mean patient age: 72 years
  • Percentage female: 37%

Inclusion criteria:

  • Ischemic or nonischemic cardiomyopathy with left ventricular ejection fraction (LVEF) 20%-50% and LV end-systolic dimension (LVESD) ≤70 mm
  • Moderate-to-severe (3+) or severe (4+) secondary MR confirmed by an independent echocardiographic core laboratory prior to enrollment (US American Society of Echocardiography criteria)
  • New York Heart Association (NYHA) functional class II-IVa (ambulatory) despite a stable maximally tolerated GDMT regimen and cardiac resynchronization therapy (CRT) (if appropriate), per societal guidelines
  • Patient has had ≥1 HF hospitalization within 12 months and/or a B-type natriuretic peptide (BNP) ≥300 pg/ml or a NT-proBNP ≥1500 pg/ml 
  • Not appropriate for mitral valve surgery by local heart team assessment
  • Interventional cardiologist believes secondary MR can be successfully treated by the MitraClip

Exclusion criteria:

  • American College of Cardiology/American Heart Association stage D HF, hemodynamic instability, or cardiogenic shock 
  • Untreated clinically significant coronary artery disease requiring revascularization
  • Chronic obstructive pulmonary disease (COPD) requiring continuous home oxygen or chronic oral steroid use 
  • Severe pulmonary hypertension or moderate or severe right ventricular dysfunction 
  • Aortic or tricuspid valve disease requiring surgery or transcatheter intervention
  • Mitral valve orifice area <4.0 cm2 by site-assessed transthoracic echocardiography
  • Life expectancy <12 months due to noncardiac conditions     

Other salient features/characteristics:

  • Prior myocardial infarction: 51%, prior percutaneous coronary intervention: 46%, prior coronary artery bypass grafting: 40%, COPD: 23%
  • Society of Thoracic Surgeons Predicted Risk of Mortality score (STS PROM) for replacement: 8.1%, ≥8%: 42%
  • High surgical risk: 69%
  • Ischemic HF: 61%
  • HF hospitalization within 1 year: 57%
  • Prior CRT: 36%
  • Echo (mean): effective regurgitant orifice area (EROA): 0.41 cm2, LVESD: 53 mm, LV end-diastolic dimension: 62 mm, LVEF: 31.3%, tricuspid regurgitation ≥2+: 16%
  • Beta-blockers: 91%, angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker/angiotensin receptor–neprilysin inhibitor: 66%, mineralocorticoid receptor antagonist: 50%

Principal Findings:

The primary effectiveness endpoint, HF hospitalization at 24 months for MitraClip + GDMT vs. GDMT, was 35.8% vs. 67.9% (hazard ratio [HR] 0.53, 95% confidence interval [CI] 0.40-0.70, p < 0.001). The primary safety endpoint, freedom from device-related complications at 12 months, was 96.6% for MitraClip (p < 0.001).

Secondary outcomes for MitraClip + GDMT vs. GDMT:

  • All-cause mortality: 29.1% vs. 46.1%, HR 0.62, 95% CI 0.46-0.82, p < 0.001
  • Death or HF hospitalization: 45.7% vs. 67.9%, p < 0.001
  • Cardiovascular death: 29.1% vs. 46.1%, p < 0.001
  • Stroke: 4.4% vs. 5.1%, p = 0.93
  • LV assist device or heart transplant: 4.4% vs. 9.5%, p = 0.01
  • Mean change in LV end-diastolic volume (LVEDV) at 1 year compared with baseline: -3.7 vs. 17.1 mm
  • MR severity ≤2% at 24 months: 99.1% vs. 43.4%, p < 0.001
  • MR severity improved by ≥2 grades: 84.1% vs. 15.9%, p < 0.0001
  • Tricuspid regurgitation severity worsened: 17.7% vs. 16.1%, p = 0.34

On echo subanalysis, it appeared that PISA and hemodynamics after MitraClip had limitations, while color Doppler, pulmonary vein flow, and vena contracta were more reliable to assess residual MR.

Quality-of-life (QoL) subanalysis:

  • Mean Kansas City Cardiomyopathy Questionnaire (KCCQ)-OS (overall summary) at baseline for MitraClip + GDMT vs. GDMT: 53.2 vs. 51.6; mean KCCQ-QoL: 45.2 vs. 44.7
  • At 24 months, mean KCCQ-OS: 70.9 vs. 61.2, p < 0.01; mean KCCQ-QoL: 71.6 vs. 58.5, p < 0.05
  • Alive and moderately improved at 24 months: 36.4% vs. 16.6%, p < 0.001
  • Alive and substantially improved at 24 months: 29.1% vs. 11.7%, p < 0.001

Interpretation:

The results of this landmark trial indicate that transcatheter mitral valve approximation using the MitraClip on a background of maximally tolerated GDMT was superior to GDMT alone in reducing HF hospitalization and mortality in symptomatic HF patients with grade 3-4+ MR. Improvements were also observed in LV dimensions and patient symptoms. Significant improvements were noted in QoL measurements starting at 1 month and sustained out to 24 months. The device had excellent safety.

All operators in this trial were experienced in the use of MitraClip. These results come on the heels of the recently published MITRA-FR trial, which did not show a benefit in this patient population. Possible reasons for differences include enrollment of patients with more severe MR (EROA >30 in COAPT vs. >20 in MITRA-FR) and less dilated ventricles (LVEDV 101 vs. 135, respectively). Procedural complications and success in reducing MR were also higher in the COAPT trial. These are truly landmark findings and will likely have a significant impact on the management of patients with secondary MR.

References:

Arnold SV, Chinnakondepalli KM, Spertus JA, et al., on behalf of the COAPT Investigators. Health Status After Transcatheter Mitral-Valve Repair in Heart Failure and Secondary Mitral Regurgitation: COAPT Trial. J Am Coll Cardiol 2019;73:2123-32.

Editorial Comment: Iung B, Messika-Zeitoun D. Transcatheter Mitral Valve Repair in Secondary MR: New Findings and New Challenges. J Am Coll Cardiol 2019;73:2133-4.

COAPT: Presented by Dr. Federico M. Asch at the American College of Cardiology Annual Scientific Session (ACC 2019), New Orleans, LA, March 17, 2019.

COAPT QoL Subanalysis: Presented by Dr. Suzanne Arnold at the American College of Cardiology Annual Scientific Session (ACC 2019), New Orleans, LA, March 17, 2019.

Stone GW, Lindenfeld JA, Abraham WT, et al., on behalf of the COAPT Investigators. Transcatheter Mitral-Valve Repair in Patients With Heart Failure. N Engl J Med 2018;379:2307-18.

Editorial: Nishimura RA, Bonow RO. Percutaneous Repair of Secondary Mitral Regurgitation — A Tale of Two Trials. N Engl J Med 2018;379:2374-6.

Presented by Dr. Gregg W. Stone at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2018), San Diego, CA, September 23, 2018.

Clinical Topics: Cardiac Surgery, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Heart Transplant, Mechanical Circulatory Support, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound, Mitral Regurgitation

Keywords: ACC19, ACC Annual Scientific Session, TCT18, Transcatheter Cardiovascular Therapeutics, Adrenergic beta-Antagonists, Cardiac Surgical Procedures, Cardiomyopathies, Coronary Artery Bypass, Echocardiography, Geriatrics, Heart-Assist Devices, Heart Failure, Heart Transplantation, Heart Valve Diseases, Mitral Valve Insufficiency, Myocardial Infarction, Myocardial Ischemia, Natriuretic Peptide, Brain, Percutaneous Coronary Intervention, Pulmonary Disease, Chronic Obstructive, Stroke, Stroke Volume


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