Transcatheter valve-in-valve implantation in degenerated surgical aortic and mitral bioprosthesis: Current state and future perspectives.

The use of bioprosthetic valves for treating patients with severe valve disease has increased over the last 2 decades, and, as a consequence, a growing number of patients with failing surgical bioprosthesis is expected in the near future. In this setting, valve-in-valve (ViV) transcatheter aortic/mitral valve replacement (TAVR and TMVR) has emerged as an alternative to redo surgery. Despite the increasing experience in ViV procedures, the development of these techniques faces several specific challenges, mainly related to the unique anatomical and physiological characteristics of ViV-TAVR/TMVR. Subsequently, various approaches have been proposed to overcome ViV-related complications and pitfalls. A growing body of evidence is currently available concerning early- and long-term clinical outcomes of patients undergoing ViV-TAVR/TMVR. These data should be comprehensively evaluated by the Heart Team in the decision-making process involving patients with failing surgical bioprostheses. In this review, we aimed to delineate the technical challenges and risks associated with ViV-TAVR and ViV-TMVR, provide an updated overview of the main clinical results, and summarize the future perspectives of this evolving field.