Abnormal flow-mediated epicardial vasomotion in human coronary arteries is improved by angiotensin-converting enzyme inhibition: A potential role of bradykinin

Abhiram Prasad, Syed Husain, Arshed A. Quyyumi

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

OBJECTIVES: This study was performed to determine whether angiotensin converting enzyme (ACE) inhibition improves endothelium-dependent flow- mediated vasodilation in patients with atherosclerosis or its risk factors and whether this is mediated by enhanced bradykinin activity. BACKGROUND: Abnormal coronary vasomotion due to endothelial dysfunction contributes to myocardial ischemia in patients with atherosclerosis, and its reversal may have an antiischemic action. Previous studies have shown that ACE inhibition improves coronary endothelial responses to acetylcholine, but whether this is accompanied by improved responses to shear stress remains unknown. METHODS: In 19 patients with mild atherosclerosis, metabolic vasodilation was assessed during cardiac pacing. Pacing was repeated during separate intracoronary infusions of low-dose bradykinin (BK) and enalaprilat. Endothelium-dependent and -independent vasodilation was estimated with intracoronary BK and sodium nitroprusside respectively. RESULTS: Enalaprilat did not alter either resting coronary vascular tone or dilation with sodium nitroprusside, but potentiated BK-mediated dilation. Epicardial segments that constricted abnormally with pacing (-5 ± 1%) dilated (3 ± 2%) with pacing in the presence of enalaprilat (p = 0.002). Similarly, BK at a concentration (62.5 ng/min) that did not alter resting diameter in the constricting segments also improved the abnormal response to a 6 ± 1% dilation (p < 0.001). Cardiac pacing-induced reduction in coronary vascular resistance of 27 ± 4% (p < 0.001) remained unchanged after enalaprilat. CONCLUSIONS: Thus ACE inhibition: A) selectively improved endothelium-dependent but not -independent dilation, and B) abolished abnormal flow-mediated epicardial vasomotion in patients with endothelial dysfunction, in part, by increasing endogenous BK activity.

Original languageEnglish (US)
Pages (from-to)796-804
Number of pages9
JournalJournal of the American College of Cardiology
Volume33
Issue number3
DOIs
StatePublished - Mar 1 1999

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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