Introduction
MV replacement in patients with severe mitral annular calcification (MAC) can lead to poor outcomes and serious issues such as patient-prosthesis mismatch (PPM). PPM in patients with MAC must be prevented as it is associated with harmful effects and its future correction is extremely challenging and related to adverse results. The current case report describes a poor outcome of transcatheter mitral valve-in-valve (ViV) replacement for the treatment of mitral PPM. Approval by the Institutional Review Board (IRB) and informed consent were waived according to our institutional policies for anonymized case reports.