Transcatheter Mitral Valve Replacement

Abstract

The use of bioprosthetic valves to treat valvular heart disease has increased over the last two decades. Although bioprosthetic valves exhibit a lower thrombogenicity than mechanical valves, which allows avoidance of long-term anticoagulation for patients in sinus rhythm, their limited durability creates a management dilemma when they degenerate. Patients with failed bioprosthetic mitral valves or rings can be treated with either redo surgery or transcatheter valve replacement. Redo mitral valve surgery is associated with an 11.1% mortality risk (according to the Society for Thoracic Surgery database), thus making transcatheter replacement a favorable alternative. The 2020 ACC/AHA guidelines for the management of patients with valvular heart disease give a 2a recommendation to valve-in-valve (ViV) interventions for bioprosthetic valve failure in patients with prohibitive surgical risk. Currently, most ViV procedures in the mitral position are performed with balloon-expandable valves designed for the treatment of degenerative aortic stenosis, which creates challenges related to device delivery, sizing, and safe and stable anchoring and sealing, particularly in non-circular anatomies. Overall, according to the available literature, procedural complications are higher for valve-in-ring (ViR) compared to ViV, perhaps due to poor patient selection. Not all rings are suitable for ViR procedures. Approaching such cases with adequate pre-procedural planning, especially with respect to the size and characteristics of the degenerated prosthesis, is paramount. Valve-in-mitral annular calcification (ViMAC) is reserved for severely symptomatic patients who are at prohibitive surgical risk. Mortality and complication rates are highest with ViMAC procedures across available registries. However, ongoing trials using dedicated prostheses for ViMAC seem to have promising safety and feasibility. In this chapter, we discuss outcome data, pre-procedural planning, procedural tips, and complications associated with ViV, ViR, and ViMAC procedures.