Transcatheter Mitral Valve Replacement in Valve-in-Valve, Valve-in-ring, and Valve-in-Mitral Annular Calcification: A Case-based Review.

Transcatheter mitral valve replacement has emerged as a viable alternative to surgery in patients with failed mitral bioprostheses, annuloplasty rings, or native disease with mitral annular calcification. This case-based review explores the evolving transcatheter mitral valve replacement landscape through 3 illustrative cases, emphasizing key aspects of preprocedural planning, technical features, and postprocedural management. Valve-in-valve procedures remain the most predictable, with encouraging mid-term outcomes. In contrast, valve-in-ring and valve-in-mitral annular calcification procedures pose greater challenges due to more complex baseline patient characteristics, anatomical intricacy, and higher procedural risk including valve embolization and paravalvular leak. Advances in dedicated transcatheter mitral valve replacement systems and refined procedural strategies have begun to address these limitations, particularly for valve-in-mitral annular calcification. Continued progress in imaging, device design, and patient selection-supported by data from ongoing pivotal trials-will be essential to safely and effectively expand the benefits of transcatheter mitral valve replacement to this anatomically and clinically high-risk population.