1999 Fiscal Year Final Research Report Summary
Preventive developments in thrombosis and intimal hyperplasia in metallic stent placement for peripheral vessels
| Project/Area Number |
09670909
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | HIROSAKI UNIVERSITY |
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Principal Investigator |
YODONO Hiraku Hirosaki University, Hospital, Division of Radiology, associate professor, 医学部・付属病院, 助教授 (30113848)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Yoshinao Hirosaki University Hospital, Department of Radiology, professor, 医学部, 教授 (10167950)
NODA Hiroshi Hirosaki University Hospital, Department of Radiology, Instructor, 医学部・付属病院, 助手 (00292152)
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| Project Period (FY) |
1997 – 1999
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| Keywords | metallic stent / thrombosis / intimal hyperplasia / prevention / coating / annimal experiments |
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| Research Abstract |
(Purpose) Thrombosis and over intimal hyperplasia as secondary effects of metallic stent placement for peripheral arteries might influence long term patency after angioplasty because they might cause stenosis or occlusion of vessels. We herein report that we have depeloped the method of thrombosis and over intimal hyperplasia prevention by making coated stents.
(Materials and Methods) Modified Z stents(GZS- 10-1.5-CF) were used in this investigation, and they were coated with teflon, silicon and hydro-polymer . To evaluate their anti-coagulant effects, we estimate coagulation volume on the surface of non-coated stent and the coated stents after soaking in human blood. To evaluate the degree of intimal hyperplasia after stent implantation, we performed the experiments with 12 dogs. We placed the four kind of stens(non-coated, and three different coated stents) into the iliac arteries of each dog under venous anesthesia. After keeping for 6 months, we sacrified them, removed the iliac arteries with stents and evaluated the degree of intimal hyperplasia by inspective and microscopic examination.
(Results) In test of anti-coagulant effect, we recognized much more clot formation on the hydro-polymer coated stent than the other stents. In evaluation of intimal hyperplasia, very thin menbranes were noted on the stents placed into the arteries of every dogs. The depths of the membranes were from 200 to 300um, and consisted of deep collagen fibers. Macrophage, neutrocyte, lymphocyte, smooth muscle cell, myofibroblast and other giant cells were not found. These were recognized as pseudcendotherization. There was no difference between these menbranes.
(Conclusions) Coated stents could not prevent over intimal hyperplasia of stented arteries, but there was a value in this experiments that vessel reaction after stenting was revealed as pseudoendothelization.
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