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J Am Coll Cardiol, 2001; 38:1188-1194 © 2001 by the American College of Cardiology Foundation |
a First Department of Internal Medicine, Fukushima Medical University, Fukushima, Japan
Manuscript received January 2, 2001; revised manuscript received May 30, 2001, accepted June 19, 2001.
Reprint requests and correspondence: Dr. Yukio Maruyama, Professor and Chairman, First Department of Internal Medicine, Fukushima Medical University, Hikarigaoka-1, Fukushima 960-1295, Japan
maruyama{at}fmu.ac.jp
OBJECTIVES
We investigated the changes in coronary vascular resistance caused by angiotensin II, angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 or 2 receptor (AT1R and AT2R, respectively) antagonists in chronic heart failure (CHF).
BACKGROUND
Angiotensin II is an intense vasoconstrictor, and increased angiotensin II in CHF might exert significant vasoconstriction.
METHODS
Eleven dogs were studied. Before and after three and five weeks of rapid pacing, coronary flow dynamics were evaluated by the coronary pressureflow relationship (PFR) in long diastole, before and after intracoronary injection of angiotensin II, the ACE inhibitor enalaprilat, the AT1R antagonist L158,809 or the AT2R antagonist PD123319
RESULTS
Before rapid pacing, angiotensin II reduced the slope of PFR (1.16 ± 0.08 to 0.81 ± 0.07 ml/min/100 g left ventricular mass per mm Hg; p < 0.01) and increased the perfusion pressure at which coronary flow ceased (zero-flow pressure [Pf = 0]), whereas enalaprilat did not change either of them. After rapid pacing, angiotensin II did not change the slope or Pf = 0. In contrast, enalaprilat increased the slope (three weeks: 1.20 ± 0.05 to 1.50 ± 0.03; five weeks: 1.25 ± 0.19 to 1.37 ± 0.08; both p < 0.05) and decreased Pf = 0 after three weeks of pacing, but not after five weeks. Pretreatment with the bradykinin antagonist HOE-140 attenuated the enalaprilat-induced increase in coronary blood flow. L158,809 and PD123319
CONCLUSIONS
This suggests that the coronary vasoconstrictive effect of angiotensin II would disappear and the vasodilatory effect of the ACE inhibitor, partly through bradykinin, would be enhanced in the early stage of CHF.
This article has been cited by other articles:
Abbreviations and Acronyms
ACE = angiotensin-converting enzyme ANP = atrial natriuretic peptide AT1R = angiotensin II type 1 receptor AT2R = angiotensin II type 2 receptor CHF = chronic heart failure NE = norepinephrine NO = nitric oxide PFR = (coronary) pressureflow relationship Pf = 0 = zero-flow pressure
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D. Merkus, D. B. Haitsma, O. Sorop, F. Boomsma, V. J. de Beer, J. M. J. Lamers, P. D. Verdouw, and D. J. Duncker
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Copyright © 2001 by the American College of Cardiology Foundation.
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