1991 Fiscal Year Final Research Report Summary
Development of a low-priced artificial heart, valve with high valvular functions
| Project/Area Number |
01890001
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Hokkaido University |
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Principal Investigator |
YUHTA Toshio Hokkaido Univ. Faculty of Eng., 工学部, 教授 (70001170)
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| Co-Investigator(Kenkyū-buntansha) |
MISHIMURA Ikuya Hokkaido Univ. Faculty of Eng., 工学部, 助手 (00228214)
SHIMOOKA Toshiyuki Hokkaido Univ. Faculty of Eng., 工学部, 助手 (50196549)
MURABAYASHI Shun Hokkaido Univ. Faculty of Eng., 工学部, 助教授 (30200306)
MITAMURA Yoshinori Hokkaido Tokai Univ. Faculty of Eng. (70002110)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Cardiac valve prosthesis / Central flow-type bileaflet valve / Duralumin / Reactive sputtering / Flow visualization / Alumina / Titanium nitride / Accelerated endurace test system |
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| Research Abstract |
In the first year ultra-duralumin was selected as a material to construct an artificial heart valve from the standpoints of price, mechanical strength, machanibility, and surface condition after machining. Stagnation and vortexes were observed in the regions distal to valve flaps and also around valve ring of commercially available valves in both computer simulation and flow visualization studies, Relatively stable flow pattern was obtained in the developed central flow-type bileaflet valve with arched flaps. Alumina was deposited on the ultra-duralumin flaps by sputtering to immprove durability and blood compatibility. Reactive sputtering deposited smoother and stronger membrane than conventional sputtering. By interposing functionally gradient material durability and adhesion of the film increased twice.
In the second year valve design was determined based on fluid dynamics in both static and dynamic flow tests. The flaps are supported by pivots and inclined at the closed position. The valve has relatively large minor orifice to obtain enough secondary flow. Activation of contact coagulation factor and also platelet. Adhesion on the sputter-deposited alumina were examined. The experiments disclosed that the alumina has as good blood ompatibility as biomaterials.
In the last year curvature of the flap, position of the pivol, and opening angle of the flap were determined based on static and dynamic flow tests and also flow visualization studies. The optimun curvature was 9%, pivot position 70%, and opening angle 67 degrees. The valve ring was machined from stainless steel and the surface was coated by TIN. The valve ring can also be machined from titanium. We also developed an accelerated endurance test system with the speed three times higher than other systems and also with lower water hammer pressure.
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