CARDIAC-VALVE ENDOTHELIAL-CELLS - RELEVANCE IN THE LONG-TERM FUNCTIONOF BIOLOGIC VALVE PROSTHESES

Objective: For reasons that are still unclear, biologic heart valve pr ostheses undergo degeneration after implantation. We studied the possi ble role of the immune system in this process. Methods: We examined th e expression of immunologically relevant molecules by human cardiac va lve endothelium in situ and in vitro and studied re-endothelialization of implanted allogeneic and xenogeneic valvular surfaces using explan ted bioprostheses and valves obtained from donor hearts at cardiac ret ransplantation. Results: We demonstrate that human cardiac valve endot helial cells express molecules capable of initiating immune responses and might therefore play a role in the degeneration of viable cardiac valve prostheses. Also, we show evidence of re-endothelialization on t he surfaces off xenografts and allografts but not on valves obtained f rom previously transplanted hearts. Conclusion: Inasmuch as valves fro m previously transplanted hearts seem to be free from degeneration, we conclude that reduction of the immunogenicity of allograft valve pros theses by HLA matching or immunosuppressive treatment might further im prove long-term results after allograft valve replacement.