Diseases of the mitral valve (MV) are the second most frequent clinically significant form of valvular disease in adults. In particular, MV regurgitation occurs with increasing frequency as part of degenerative changes in the ageing process.1
The annual incidence of degenerative MV disease is estimated at approximately 2–3 %. In addition to degenerative valve disease, MV regurgitation can be caused by cardiac ischaemia (functional mitral regurgitation), infective endocarditis and rheumatic diseases (prevalent in less developed countries).1 Severe mitral regurgitation (MR) develops gradually over the years and carries a high annual mortality rate of at least 5 %.2 Medical therapy relieves symptoms but does not reverse the underlying mitral pathology.
Conventional surgical repair or replacement has been the standard of care for symptomatic severe MR.3,4 Those with degenerative MR (DMR) have excellent outcomes with repair surgery.5 However, the long-term benefits of surgical treatment of functional MR (FMR) are harder to demonstrate and remain controversial.6,7
Before the emergence of transcatheter valve therapies, optimal medical therapy and cardiac resynchronisation therapy in selected candidates have been the only treatment for patients deemed too high-risk for conventional surgery.8–11 Although a variety of MV transcatheter therapies grew in parallel with aortic valve therapies, the MV therapies have had a slower development path.2 Percutaneous edge-to-edge MV repair with the Mitraclip® system was demonstrated to be a safe and feasible alternative to surgical treatment for severe MR.12–15 Adverse valve morphology and severe left ventricular dysfunction have been the two major challenges for the treatment with the Mitraclip system.16–18
Multidisciplinary assessment is essential for high-risk patients. A heart team including surgeons, interventional cardiologists, clinical cardiologists and imaging experts should discuss individual cases, considering the surgeon’s/institution experience with MV repair versus replacement.