Je. Sanderson et al., ENDOTHELIUM-DEPENDENT DILATION OF THE CORONARY-ARTERIES IN SYNDROME-X- EFFECTS OF THE COLD PRESSOR TEST, Cardiology, 88(5), 1997, pp. 414-417
The coronary flow reserve is abnormal in syndrome X, but the response
to the cold presser test, which in normals produces flow-mediated endo
thelium-dependent epicardial coronary dilation, has not been studied.
In this study, in 12 patients with typical syndrome X and angiographic
ally normal coronary arteries, the response to the cold presser test w
as 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 presser test, and the coronary vascular resistance increased sign
ificantly (from 2.4 +/- 1.1 to 3.2 +/- 1.7 mm Hg/cm.s(-1).mm(2.); 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 presser test.