Digital Designing And Manufacturing Of The Bioprosthetic Heart Valves

In terms of engineering, human's heart works as a pump, while the heart valve is the check valve forcing the blood to flow in a expected direction. If there are some diseases of the heart valve, the main therapy is to use the prosthetic heart valve, but medicine just is an assistant method. Heart valve disease poses a significant public health risk. Since the early 1960s, prosthetic heart valve have been used in the treatment of cardiovalvular disease. These artificial heart valve can be classified as the mechanical heart valve or the bioprosthetic heart valve (BHV). Each of them have their own advantages and disadvantages, and both of them are used. Although mechanical valves exhibit better durability, patients must undergo anticoagulation therapy for the remainder of their lives due to an increased risk of thrombosis. On the other side, BHV is improved in antithrombotic, and its flow pattern is unobstructed central flow pattern which is similar to human heart valve. But they often failed due to leaflet calcification and tearing, which affect its durability. In order to prolong the lifetime of BHV, the research on the stress analysis on the BHV leaflet and the precision modeling on the BHV stent should be studied further.The stress distribution of curved surface with different shapes, such as cylindrical surface, spherical surface, paraboloidal surface and ellipsoid surface, is analyzed based on Membrane theory. The ellipsoid surface finally is chosen to be the one to manufacture the BHV, according to the surface stress analysis given by the finite element software, By Pro/E software, the solid model of the supporting stent and the casting mould of three dimensions are designed. The casting mould is worked by the wire cut electrical discharge machine, the carving miller and the electric spark machine. The problem of the elastic deformation of the valvular stent is solved by compensative method. Finally, the finished production of the BHV stent is consistent with the theoretical design. The method to manufacture the BHV stent will be useful to prolong the lifetime of the BHV and to improve clinical practice.