State of the ArtCoronary insufficiency (CI) is the state in which an imbalance occurs between the supply and demand of oxygen, which prevents adequate maintenance of the metabolic needs of the myocardium, resulting in ischemia of several degrees of intensity.CI has numerous causes among which are cardiac valvular diseases (aortic stenosis), hypertrophic cardiomyopathy, microvasculature diseases (diabetes mellitus, syndrome X), anomalous origin of coronary arteries, and coronary fistulas.However, the most important cause, because of its frequency and the resulting morbidity and mortality, is atherosclerotic obstructive CI.Therefore, this discussion will be specifically about coronary atherosclerosis.The main objective is not to suggest practical applications for specific situations, but to outline concepts, based on critical analysis of data in the literature, which may provide a basis for conducting further investigation and for providing treatment of coronary artery disease (CAD).