TY - JOUR
T1 - Preliminary study on the new self-closing mechanical mitral valve
AU - Naemura, Kiyoshi
AU - Umezu, M.
AU - Dohi, T.
PY - 1999/10/4
Y1 - 1999/10/4
N2 - A natural mitral valve starts closing before systole. Conventional mechanical 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 pulse duplicator and an x-ray high-speed video camera. Comparative study was conducted under 60 bpm and 4 L/min as the mean flow rate. It was clarified that the self-closing 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 vane (sewing ring diameter 29 mm) was obtained from the experiment that momentum of inertia of the leaflet should be less than 14.9 x 10-9 kg·m2 and the torque caused by gravity should be more than 4.2 x 10-6 N·m, and only one leaflet should be designed as self-closing, and surgeons need to pay attention to the positioning of the two leaflets. In conclusion, the preliminary study showed the ability of starting to close before systole and the design strategy for future prototyping.
AB - A natural mitral valve starts closing before systole. Conventional mechanical 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 pulse duplicator and an x-ray high-speed video camera. Comparative study was conducted under 60 bpm and 4 L/min as the mean flow rate. It was clarified that the self-closing 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 vane (sewing ring diameter 29 mm) was obtained from the experiment that momentum of inertia of the leaflet should be less than 14.9 x 10-9 kg·m2 and the torque caused by gravity should be more than 4.2 x 10-6 N·m, and only one leaflet should be designed as self-closing, and surgeons need to pay attention to the positioning of the two leaflets. In conclusion, the preliminary study showed the ability of starting to close before systole and the design strategy for future prototyping.
KW - Center of gravity of the leaflet
KW - Design
KW - Final closing speed
KW - Mechanical mitral valve
KW - Motion measurement
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U2 - 10.1046/j.1525-1594.1999.06257.x
DO - 10.1046/j.1525-1594.1999.06257.x
M3 - Article
C2 - 10491036
AN - SCOPUS:0032851568
VL - 23
SP - 869
EP - 875
JO - Artificial Organs
JF - Artificial Organs
SN - 0160-564X
IS - 9
ER -