Current status of transcatheter mitral valve repair therapies - From surgical concepts towards future directions.

Transcatheter mitral valve (MV) intervention has emerged as an effective treatment option for symptomatic severe mitral regurgitation (MR) in patients considered to be inoperable or at high operative risk for surgical MV surgery. In primary mitral regurgitation, surgical repair is the standard of care. Transcatheter edge-to-edge MV repair with the MitraClip system has the largest clinical experience to date and offers a sustained clinical benefit in selected surgical high-risk patients. Surgery for secondary MR remains a challenge. Indications and the preferred surgical procedure remain controversial, mainly because of high recurrence rate of MR and the absence of evidence for survival benefit after surgery. Secondary MR is currently the most common indication for MitraClip use in Europe. Many registries show the safety of this procedure and improvements in patient symptoms and quality of life after 1 year, but most patients still have considerable residual MR. Other transcatheter MV repair devices are still in their early experiences. However, durability, safety, and possible damage of adjacent cardiac structures remain important concerns. Future directions for treatment of patients with secondary MR will depend on outcomes from the clinical trials in progress, whatever the use of transcatheter techniques is expected to expand substantially in the next years. This review aims to provide an overview of transcatheter MV interventions, emerging from surgical concepts, including leaflet repair, chordal replacement, and annuloplasty, and to discuss the challenges they face and future directions in achieving successful clinical application.