Introduction: transcatheter mitral valve replacement (TMVR) is indicated in case of degenerated bioprosthesis in high-risk patients. however, durability of these valves still represents an important issue. methods: early severe structural valve deterioration of a mitral porcine surgical bioprosthesis and of a subsequent bovine TMVR, both at 4 years follow-up, is here presented. results: gross, histopathologic, and X-ray examination revealed massive calcification of both devices and fibrous tissue overgrowth involving the TMVR stent. conclusions: careful clinical evaluation and strict follow-up are mandatory to identify early signs of dysfunction and to intervene in a timely manner
