JaLCDOI 10.18926/AMO/32442
FullText URL fulltext.pdf
Author Saito, Daiji| Yasuhara, Koichiro| Takeda, Kou| Hyodo, Tatsuo| Fujii, Akinobu| Uchida, Toshiaki| Abe, Yukihiro| Haraoka, Shoichi| Nagashima, Hideo|
Abstract <p>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.</p>
Keywords coronary cinstriction open-chest dog distal coronary pressure
Amo Type Article
Published Date 1983-02
Publication Title Acta Medica Okayama
Volume volume37
Issue issue1
Publisher Okayama University Medical School
Start Page 59
End Page 66
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 6846053
Web of Sience KeyUT A1983QD83600007
JaLCDOI 10.18926/AMO/30698
FullText URL fulltext.pdf
Author Saito, Daiji| Yasuhara, Koichiro| Takeda, Hikaru| Hyodo, Tatuo| Yamada, Nobuyuki| Uchida, Toshiaki| Haraoka, Shoichi| Nagashima, Hideo|
Abstract <p>Changes in the stenotic resistance of a coronary artery following brief coronary occlusion were studied in the anesthetized open-chest dog. A critical coronary stenosis was constructed by tying a thick string around the circumflex coronary artery (LCx) near its origin. The LCx was occluded for 5, 10, 15, 20 and 30 seconds with and without coronary stenosis then the reactive hyperemia was observed. In the absence of the stenosis, resistance of the segment of the large coronary artery remained unchanged during the reactive hyperemia independent of the duration of occlusion. In the presence of the stenosis, however, stenotic resistance increased for a certain time after the release of occlusion. This increased resistance lasted longer with more severe stenosis and with longer duration of coronary occlusion. These results suggest that stenotic resistance can increase dynamically, and that the duration of increased resistance may reflect the severity of the stenosis.</p>
Keywords stenotic resistance reactive hyperemia distal coronary pressure
Amo Type Article
Published Date 1982-06
Publication Title Acta Medica Okayama
Volume volume36
Issue issue3
Publisher Okayama University Medical School
Start Page 199
End Page 205
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 7113744
Web of Sience KeyUT A1982NV62100004