Potassium Channel Openers in Therapy, Current Uses, and Perspectives: Cardiac Ischemia and Angina

Abstract

The myocardial blood flow regulation in coronary artery disease has been a matter of controversy for a long time. In the past, much of the literature focused on the characterization of coronary stenoses which were considered the major determinant of perfusion abnormalities observed in such a disorder. However, it is now well recognized that the hydraulics of epicardial obstruction can not be considered solely responsible for all phenomena which are observed in these patients. In fact, several recent studies demonstrated that atherosclerosis induces more complex changes in vascular physiology, leading to a microvascular dysfunction (and reduced vasodilating capability) even in regions supplied by angiographically normal vessels [1 3]. Although the exact mechanisms of these puzzling findings have not been fully elucidated, several authors suggested that mechanisms regulating coronary blood flow could be much more complex than previously thought and that coronary atherosclerosis might produce profound alterations in vascular smooth muscle and endothelial function in both large epicardial arteries and coronary microvasculature, even in the absence of significant lumen reduction [4 6].