Endothelial dysfunction and coronary artery spasm.

Coronary spasm plays an important role in the pathogenesis of not only variant angina but also coronary heart disease in general including acute coronary syndromes. The incidence of coronary spasm in Japanese patients with angina pectoris was about 40%. The total number of patients with angina pectoris increases with old age. The patients' age distribution was relatively younger in the coronary spasm than in the stable effort angina. The vascular endothelium has been reported to be a multifunctional organ whose integrity is essential to normal vascular physiology, and whose dysfunction can be a critical factor in the pathogenesis of vascular disease. Acetylcholine and methacholine cause vasodilation by endothelium-derived relaxing factor when endothelium is functioning normal, whereas they cause vasoconstriction when endothelium is removed or damaged. Coronary spasm can be induced by acetylcholine and methacholine. The patients with coronary spasm may have a disturbance in the endothelial function of the coronary arteries.