Endothelium-dependent dilation of the coronary arteries in syndrome X: effects of the cold pressor test.
The coronary flow reserve is abnormal in syndrome X, but the response to the cold pressor test, which in normals produces flow-mediated endothelium-dependent epicardial coronary dilation, has not been studied. In this study, in 12 patients with typical syndrome X and angiographically normal coronary arteries, the response to the cold pressor test was abnormal with a mean fall in diameter (10 +/- 8%) in 6 patients, no change in 1, and a minimal increase (4 +/- 2%) in 5 patients (normal increase 12 +/- 1%). The coronary blood flow fell slightly during the cold pressor test, and the coronary vascular resistance increased significantly (from 2.4 +/- 1.1 to 3.2 +/- 1.7 mm Hg/cm.s-1.mm2; p = 0.05), both abnormal responses. This study confirms that in syndrome X patients there is coronary endothelial dysfunction which is apparent in response to physiological stimuli induced by the cold pressor test.
Sanderson
J E
JE
Department of Medicine, Chinese University of Hong Kong, Prince of Wales Hospital.
Woo
K S
KS
Chung
H K
HK
Chan
W M
WM
Tse
K K
KK
White
H D
HD
D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003080:Cold Temperature; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D017566:Microvascular Angina / Q000503:physiopathology*; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology; D012212:Rheology / Q000187:drug effects; D014463:Ultrasonography; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation
D005996:Nitroglycerin