The treatment of mitral insufficiency in refractory heart failure

Secondary mitral insufficiency (SMI) is caused by dilatation and left ventricular dysfunction and is a frequent finding in patients with heart failure (HF). It is associated with a mortality of between 40% and 50% at 3 years. The first-line treatment is represented by medical therapy, possibly associated, when indicated, with cardiac resynchronization. If the patient remains symptomatic, corrective action should be considered. Surgery is indicated in cases of severe SMI with ejection fraction >30% and the need for myocardial revascularization. The management of patients in whom revascularization is not an option remains extremely complex and the evidence in this field is extremely limited. Percutaneous transcatheter therapies, reparative or replacement, are rapidly emerging as valid alternatives in cases of patients at high surgical risk. In particular, edge-to-edge repair (MitraClip) has proven effective in improving symptoms and reducing hospitalizations for HF. However, neither transcatheter nor surgical mitral repair or replacement has been shown to significantly improve prognosis, with mortality remaining high (14-20% at 1 year). Randomized trials aimed at assessing the effect of these treatments and establishing their long-term outcomes are urgently required.