| Project/Area Number |
60870045
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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 |
Thoracic surgery
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| Research Institution | Hokkaido University |
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Principal Investigator |
MITAMURA Yoshinori Research Institute of Applied Electricity, Hokkaido Univ., Associate Prof., 応用電気研究所, 助教授 (70002110)
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| Co-Investigator(Kenkyū-buntansha) |
AMINO Hirokazu Kyocera Corp., Bioceram Division, Researcher, バイオセラム事業部, 研究員
北村 安弘 京セラ, バイオセラム事業部, 研究員
YUTA Toshio Faculty of Engineering, Hokkaido Univ., Professor, 工学部, 教授 (70001170)
MIKAMI Tomohisa Research Institute of Applied Electricity, Hokkaido Univ., Professor, 応用電気研究所, 教授 (00001678)
KITAMURA Yasuhiro Kyocera Corp., Bioceram Division, Researcher
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥9,900,000 (Direct Cost: ¥9,900,000)
Fiscal Year 1986: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1985: ¥7,700,000 (Direct Cost: ¥7,700,000)
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| Keywords | Artificial Heart Valve / Ceramics / Alumina / Titanium Nitride / 抗血栓性 / 人工弁 / 単結晶アルミナ |
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| Research Abstract |
A durable, thromboresistant tilting flat disk-type valve was developed. It is comprised of a thin (0.6 mm) single-crystal alumina ceramic disk and titanium nitride housing. The housing was milled from a single piece of titanium and coated with titanium nitride by ion plating.
(1) Critical surface tension was 32 dyne/cm for titanium nitride, and 26 dyne/cm for single crystal alumina and LTI carbon. These are nearly equal to the value of 20-30 dyne/cm in which the critical surface tensions of most blood compatible biomaterials range.
(2) The single-crystal alumina and titanium nitride showed excellent blood compatibility in vena cava ring tests. Two weeks after implantation one alumina ring showed no thrombi, and the other 4 rings showed a small amount of clot formation at the edges. Three titanium nitride rings showed no thrombi, and the other 2 rings showed a small amount of clot formation at the edges after 2 weeks.
(3) Durability testing under high pressure ( up to 1750 mmHg) pulsatile conditions showed that the safety factor appears to be at least 7 times what could be experienced in vivo.
(4) Pin on disk wear testings were conducted for measuring the wear rates of the single-crystal crystal alumina and titanium nitride. The wear factor of titanium nitride ( vs single crystal alumina ) was 1.8 X <10^(-7)> <mm^3> /Nm, which would indicate a long life of the valve.
(5) The pressure gradient of the ceramic valve was lower than that of the Bjork-Shiley, and nearly equal to those of the Omni-Science and SJM valves. The opening time of the valve disk was measured by optical sensor. The ceramic valve opened most quickly among commercially available valves.
(6) The ceramic valve was incorporated into a pneumatic assist pump as an outflow valve and was implanted in 2 sheep. After 5 days, no thrombi were observed on the ceramic valves although a thrombus was found on the conventional valves used as an inflow valve.
The ceramic valve is a promising heart valve.
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