COAPT Trial: Transcatheter Mitral Valve Repair Leads to Early and Sustained Health Improvements in Patients with Secondary Mitral Regurgitation

A study led by Dr. Suzanne Arnold published in the Journal of American College of Cardiology showed that in patients with heart failure secondary to mitral regurgitation, transcatheter mitral valve repair resulted in early and sustained health status improvement compared with medical therapy alone.

The COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) demonstrated that transcatheter mitral valve repair (TMVr) was superior to guideline-directed medical therapy in reducing heart failure hospitalization and mortality in symptomatic heart failure patients with grade 3-4 mitral regurgitation. In addition to prolonging survival and reducing hospitalization, improving a patient’s health status is a key goal of treatment with TMVr. The effect of TMVr on the health status of patients with secondary mitral regurgitation is currently not known. Using the results of COAPT, the investigators aimed to address this knowledge gap.

The COAPT trial was a multicenter, randomized open-label trial that enrolled patients with 3+ and 4+ secondary mitral regurgitation with an ejection fraction ranging from 20% to 50% who were symptomatic despite maximally tolerated guideline-directed therapy. Patients were randomized to either TMVr or standard of care and followed up for a minimum of 1 year (and up to 2 years). Health status was evaluated at baseline, 1, 6, 12, and 24 months using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the Medical Outcomes Study Short Form 36 (SF-36) Health Survey.

Out of the 614 patients enrolled, 302 were randomized to TMVr and 312 to standard care. At baseline, both groups had an impaired health status (mean KCCQ score – 52.4). Unlike patients in the standard care arm, patients randomized to TMVr had an improvement in their health outcome by 1 month (mean difference between the two groups: 15.9 points, 95% CI 12.3 to 19.5 points). The difference remained significant at 24 months (mean difference of 12.8 points, 95% CI 7.5 to 18.2 points). Additionally, 36.4% of TMVr patients were alive at 24 months with a moderately large improvement in their KCCQ score (10 points or more), compared to 16.6% of patients (p < 0.001, for a number needed to treat of 5.1). Patients in the TMVr arm also reported a better overall health outcome status, as indicated by SF-35, at 24 months.

The COAPT trial previously demonstrated that TMVr reduced mortality and heart failure hospitalization in patients with secondary mitral regurgitation. This study demonstrated that TMVr led to an improvement in symptoms, functional status and quality of life. This effect was evident by 1 month and continued through to 24 months of follow up. The investigators highlight the value of TMVr in patients with secondary mitral regurgitation. Dr. Arnold wrote, “Considering the previously reported benefits of TMVr on survival and HF hospitalization, these health status findings further support TMVr as a valuable treatment option for HF patients with severe secondary MR who remain symptomatic despite maximally tolerated guideline-directed medical therapy.” In an editorial, Dr. Bernard Iung recognizes the implications of this study and also compares its findings with a similar trial that used mitral clips in secondary mitral regurgitations. Dr. Iung said, “The findings by Arnold et al. represent an important contribution in the knowledge of the treatment of secondary MR. However, considerable challenges remain with regard to clinical practice. The first step is to identify which patients with secondary MR are good candidates for TMVr. In contrast to the COAPT trial, the MITRA-FR (Percutaneous Repair with the MitraClip Device for Severe Functional/ Secondary Mitral Regurgitation) trial did not show any benefit on survival free of heart failure hospitalization. These contradictory findings have already generated a number of comments.” Ultimately, Dr. Iung highlights the need to identify factors that would predict futile TMVr procedures in patients with secondary mitral regurgitation.