Transcatheter Mitral “Valve-in-Ring” Implantation: A Word of Caution

Transcatheter mitral valve-in-valve and valve-in-ring procedures have emerged as a potential alternative for patients with failed mitral bioprosthesis or mitral valve repair who are at very high or prohibitive surgical risk. However, transcatheter mitral valve-in-ring implantation (TMViRI) remains a challenging procedure, partially because of the oval shape of mitral rings, which may lead to prosthesis dysfunction when the ring is not able to adopt the circular shape of the transcatheter valve. We present a case of failed TMViRI in a dysfunctional mitral homograft. The potential factors leading to procedural failure are discussed.