Update on percutaneous mitral valve therapy: clinical results and real life experience

Mitral regurgitation (MR) is a common valvulopathy worldwide increasing in prevalence. Cardiac surgical intervention, preferable repair, is the standard of care, but a relevant number of patients with severe MR do not undergo surgery because of high peri-operative risk. Percutaneous mitral valve repair with the MitraClip System has evolved as a new tool for the treatment of severe MR. The procedure simulates the surgical edge-to-edge technique, developed by Alfieri in 1991, creating a double orifice valve by a permanent approximation of the two mitral valve leaflets. Several preclinical studies, registries and Food and Drug Administration approved clinical trials (EVEREST, ACCESS-EU) are currently available. The percutaneous approach has been recently studied in a randomized controlled trial, concluding that the device is less effective at reducing MR, when compared with surgery, by associated with a lower adverse event rate. The patients enrolled in this trial had a normal surgical risk and mainly degenerative MR with preserved left ventricular function. On the other hand, results derived from the clinical "real life" experience, show that patients actually treated in Europe present a higher surgical risk profile, more complex mitral valve anatomy and functional MR in the most of cases. Thus these data suggest that MitraClip procedure is feasible and safe in this subgroup of patients that should be excluded from the EVEREST trial due to rigid exclusion criteria. Despite the promising results clinical experience is still small, and no data related the durability are currently available. Therefore, MitraClip device should be reserved now to high risk or inoperable patients.