title: The relationship between flow-mediated brachial artery vasodilation and coronary vasomotor responses to bradykinin: comparison with those to acetylcholine.
abstract: Flow-mediated dilation (FMD) of brachial artery provides a noninvasive assessment of coronary endothelial dysfunction. Acetylcholine (ACh) has been used as an agent for estimating coronary endothelial function. In contrast to ACh, there is no evidence for a relationship between FMD and coronary vasodilation to bradykinin (BK). The aim of this study was to compare the flow-mediated vasodilation of brachial artery with coronary vasomotor responses to intracoronary ACh or BK in patients with an angiographically normal left anterior descending coronary artery. Ninety-one patients underwent the cardiac catheterization examination with coronary endothelial function testing and the brachial ultrasound study. BK (0.2, 0.6, 2.0 microg/min) and ACh (3, 10, 30 microg/min) were administered into the left coronary artery in a stepwise manner. Coronary blood flow was evaluated by the Doppler flow velocity measurement. Coronary diameters were measured by the quantitative coronary angiography. The assessment of endothelial function in the brachial artery was made in response to reactive hyperemia with high-resolution ultrasound. Bradykinin induced dose-dependent increases in epicardial coronary diameter and blood flow. There was a significant positive correlation between FMD- and BK-induced vasodilations of epicardial coronary arteries (0.2 microg/min: r = 0.30; 0.6 microg/min: r = 0.42; 2.0 microg/min: r = 0.44, P < 0.01, respectively) and resistance coronary arteries (0.2 microg/min: r = 0.40; 0.6 microg/min: r = 0.56; 2.0 microg/min: r = 0.59, P < 0.0001, respectively). FMD correlated with ACh-induced vasomotions of resistance but not epicardial coronary arteries. No correlation was seen between nitroglycerin-induced brachial artery vasodilation and BK-induced coronary vasodilation. The endothelial dysfunction of peripheral arteries correlated well with that of the coronary arteries especially vasomotor responses to BK.
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan. smatsuo@belle.shiga-u.ac.jp
authors.forename: Shinro
authors.initials: S
authors.lastname: Matsuo
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takashima
authors.forename: Naoto
authors.initials: N
authors.lastname: Ohira
authors.forename: Tetsunobu
authors.initials: T
authors.lastname: Yamane
authors.forename: Yo
authors.initials: Y
authors.lastname: Yasuda
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tarutani
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D000109:Acetylcholine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000328:Adult; D000368:Aged; D001916:Brachial Artery / Q000502:physiology* / Q000503:physiopathology; D001920:Bradykinin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006328:Cardiac Catheterization / Q000379:methods; D003324:Coronary Artery Disease / Q000175:diagnosis; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000187:drug effects / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D005260:Female; D006801:Humans; D007261:Infusions, Intra-Arterial; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000187:drug effects; D014463:Ultrasonography; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000502:physiology*; D014666:Vasomotor System / Q000187:drug effects / Q000502:physiology*
chemical_list: D000109:Acetylcholine; D001920:Bradykinin