Functional mitral regurgitation

Purpose of review Functional mitral regurgitation (FMR) is a complex condition in which significant mitral regurgitation coexist with cardiomyopathy and heart failure and carries an increased risk for associated morbidity and mortality. In addition to guideline-directed medical therapy and cardiac resynchronization therapy, percutaneous transcatheter mitral valve repair (TMVr) is a new therapeutic option but requires careful selection of the proper candidates. We describe the different mechanisms of functional mitral regurgitation, review echocardiographic parameters to assess its severity, and discuss recently published relevant studies including TMVr. Recent findings Two randomized controlled trials assessing the efficacy and safety of TMVr using the MitraClip in patients with heart failure and severe functional mitral regurgitation were published: MITRA-FR (Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation) and COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation). The results of these trials were opposite: although MITRA-FR failed to show clinical benefit, COAPT showed a dramatic clinical and echocardiographic benefit from transcatheter mitral valve repair using the MitraClip device. We discuss these two important trials and how differences in patient enrollment could explain the discrepant results and the manner they may influence future studies and clinical practice. Patients with FMR receiving optimal guideline-directed medical therapy and cardiac resynchronization therapy who meet specific clinical and echocardiographic criteria can benefit from transcatheter mitral valve repair.