Mitral valvular disease, and specifically mitral valve regurgitation is the most common valve disease in the US. Currently mitral valve surgery (open heart surgery), either with repair or replacement, is the standard of care for patients with symptomatic mitral valve disease. Transcatheter mitral valve replacement (TMVR) is an emerging therapy that could offer patient a less invasive alternative to open heart surgery. The goal of the APOLLO trial is to evaluate whether TMVR is non-inferior to conventional mitral surgery with respect to composite endpoint rate of all-cause mortality, all stroke, reoperation (or reintervention) and cardiovascular hospitalization at one year in patients with severe symptomatic native mitral regurgitation. The secondary objectives of this trial are to assess differences in quality of life, clinical benefit (efficacy endpoints) and health economics in patients with severe symptomatic native mitral regurgitation.