English: Replaceable models of heart valve prostheses

Mechanical or biological (bioprostheses or "tissue valves"), the replaceable models of implantable heart valve prostheses are made by two or three mechanical components. The gear attachment mechanism usually uses the coil effect or the bayonet coupling system. The replaceable models of implantable heart valve prostheses are typically supplied with a sewing or suturing ring surrounding the valve body or stent that is to be sutured by the surgeon to the valvar rim. The biggest challenge in this type of prostheses is the difficulty in its future removal. This is due to the formation of pannus fibrotic around the valve body and sewing ring. To separate the parts is very laborious, keeping intact the sewing ring, which will be used in the coupling of the new valve. To easily remove the old replaceable bioprostheses, its "stent" can be sectioned to dismount its framework and so facilitate its removal from the sewing ring.

Estudo in vitro, de uma bioprotese recambiavel. Lyra, R M.