ID | 32442 |
JaLCDOI | |
FullText URL | |
Author |
Saito, Daiji
Yasuhara, Koichiro
Takeda, Kou
Hyodo, Tatsuo
Fujii, Akinobu
Uchida, Toshiaki
Abe, Yukihiro
Haraoka, Shoichi
Nagashima, Hideo
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Abstract | The effects of intravenous infusion of isoproterenol on stenosis resistance were studied in the anesthetized open-chest dog. The circumflex coronary artery (LCx) was isolated near its origin and an electromagnetic flow transducer was placed around the vessel for measuring coronary flow. A polyethylene catheter was inserted into the small branch of LCx for monitoring distal coronary pressure. LCx was constricted with a thick cotton string to a degree of obstruction that eliminated reactive hyperemia following a 20-second coronary occlusion. The coronary resistance across the stenotic segment (RL) was calculated as the pressure gradient across the stenosis divided by coronary flow. Isoproterenol was infused intravenously in a dose to keep the heart rate at a level 25-30% above the control with and without coronary constriction. For maintaining the ascending aortic pressure at the pre-isoproterenol level, the descending thoracic aorta was constricted with a tape. In the absence of coronary constriction, the vascular resistance of large coronary arteries was not affected by isoproterenol with a significant increase in coronary flow. In the presence of coronary stenosis, isoproterenol markedly increased RI regardless of additional aortic constriction. The magnitude of the increase in RL during aortic constriction varied directly with the percent increase in the pressure gradient across the coronary stenosis. Pacing-tachycardia essentially did not affect RL. These results suggest that isoproterenol increased the vascular resistance of the stenotic segment with fixed caliber. |
Keywords | coronary cinstriction
open-chest dog
distal coronary pressure
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Amo Type | Article
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Publication Title |
Acta Medica Okayama
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Published Date | 1983-02
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Volume | volume37
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Issue | issue1
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Publisher | Okayama University Medical School
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Start Page | 59
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End Page | 66
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ISSN | 0386-300X
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NCID | AA00508441
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Content Type |
Journal Article
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language |
English
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File Version | publisher
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Refereed |
True
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PubMed ID | |
Web of Science KeyUT |