Coronary segmental responses to acetylcholine and bradykinin in patients with atherosclerotic risk factors.
This study was designed to elucidate the nature of coronary endothelial dysfunction in patients with hypertension and/or hypercholesterolemia and normal smooth coronary arteries by evaluating the coronary vascular responses to acetylcholine and bradykinin. The study included 19 patients (10 men; age [mean +/- SD] 61 +/- 9 years) with angiographically normal smooth coronary arteries and either hypertension (n = 7) and/or hypercholesterolemia (n = 13). Patients received acetylcholine (3 or 30 microg/min) infusions followed by bradykinin (0.5, 1.5, 2.5 microg/min) and nitroglycerin (200 microg/min) infusions into the left coronary ostium. Epicardial coronary artery diameters were measured by quantitative angiography. Angiography detected both vasoconstricted and dilated segments following acetylcholine infusion. Bradykinin significantly dilated both types of segments (p <0.001, respectively). However, bradykinin-induced dilation was significantly greater in segments exhibiting acetylcholine-induced vasodilation than in those exhibiting vasoconstriction (p <0.01 in the proximal portion and p <0.02 in the distal portion). Nitroglycerin-induced dilation was similar in all segments. These results suggest that coronary endothelial dysfunction may be a heterogeneous process in patients with coronary risk factors. Moreover, the mechanism underlying diminished endothelium-dependent dilation involves not only the muscarinic receptor, but also B2-kinin receptor.
Kato
M
M
First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
Shiode
N
N
Yamagata
T
T
Matsuura
H
H
Kajiyama
G
G
D000109:Acetylcholine / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D001161:Arteriosclerosis / Q000209:etiology / Q000503:physiopathology*; D001920:Bradykinin / Q000494:pharmacology*; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000187:drug effects* / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006937:Hypercholesterolemia / Q000150:complications / Q000503:physiopathology; D006973:Hypertension / Q000150:complications / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology; D012307:Risk Factors; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D005996:Nitroglycerin; D000109:Acetylcholine; D001920:Bradykinin