Transcatheter therapies for secondary mitral regurgitation in advanced heart failure: what are we aiming for?

A severe secondary mitral regurgitation (SMR) can be found in a significant portion of patients affected by advanced heart failure (AHF). Conventional therapies (optimal medical therapy, devices, surgery) present restricted clinical efficacy in this stage of the left ventricle disease which is burdened by high mortality and morbidity rates. Although the treatment of choice is represented by heart transplantation (HTx), there is an unmet need related to the limited supply of donor hearts (as opposed to the growing prevalence of AHF) and the low eligibility of highly symptomatic patients. In case of concomitant severe SMR, transcatheter mitral valve therapies (repair and replacement) may play a crucial role in this setting. While a direct prognostic improvement after correction of SMR has yet to be proved, AHF patients can benefit from the following: hemodynamic stabilization, symptomatic relief, normalization of pulmonary arterial pressures, and reduction in hospitalizations for acute heart failure. Obtaining these results may lead to the clinical consequences of reaching the HTx in good enough clinical status (bridge to heart transplantation), becoming eligible for the HTx (bridge to HTx candidacy), and being delisted for clinical improvement (bridge to recovery). Therefore, achieving traditional secondary endpoints in patients with AHF and SMR can translate into significant clinical implications.