Intravascular ultrasonic evidence by constant cross-sectional area of atherosclerotic plaques during coronary vasomotion in humans.

AIMS This study aims to visualize ultrasonically deformation of atherosclerotic plaques in human coronary arteries during vasoconstriction and vasodilatation. METHODS AND RESULTS Intravascular ultrasound detected occult atherosclerosis in angiographically normal coronary arteries of eight patients with chest pain at rest. During the acetylcholine provocative test, intravascular ultrasound monitored deformation of the atherosclerotic plaques. At the last step of the test, intracoronary injection of isosorbide dinitrate caused vasodilation. Under control, acetylcholine-treated, and isosorbide dinitrate-treated conditions, cross-sectional areas of sonolucent circle and vessel lumen were measured. Subtraction of the latter from the former gave the area of atherosclerotic plaque. In the process of vasoconstriction and vasodilation, the plaque area did not change significantly. CONCLUSION The cross-sectional area of the atherosclerotic plaque appeared to be constant during vasomotion of human coronary arteries.