Preliminary study on the new self-closing mechanical mitral valve

A natural mitral valve starts closing before systole. Conventional mechanic al mitral valves start their closing motion after systole. In order to let the mechanical mitral valves start closing before systole, we propose a new self-closing Valve by adjusting the center of gravity of the leaflet. As a first step, we adjusted the center of gravity by attaching a block of lead to the leaflet of a CarboMedics bileaflet valve and evaluated it using a p ulse duplicator and an x-ray high-speed video camera. Comparative study was conducted under 60 bpm and 4 L/min as the mean now rate. It was clarified that the self-dosing valve started closing before systole, no influence on inflow volume was found, the final closing speed of the self-closing valve just before complete closure was slower than the conventional valve (1.9-0. 34 m/s), a design strategy of a self-closing valve (sewing ring diameter 29 mm) was obtained from the experiment that momentum of inertia of the leafl et should be less than 14.9 x 10(-9) kg.m(2) and the torque caused by gravi ty should be more than 4.2 x 10(-6) N . m, and only one leaflet should be d esigned as self-closing, and surgeons need to pay attention to the position ing of the two leaflets. In conclusion, the preliminary study showed the ab ility of starting to close before systole and the design strategy for futur e prototyping.