The old paradigm states that the greater the stenosis, the greater the risk of cardiac events. Revascularization procedures are the only effective approach to improving prognosis associated with coronary artery disease. In contrast, on the basis of the new paradigm, the nature of the plaque determines the risk of acute cardiovascular events. Dangerous plaques have a lipid-rich core with surrounding inflammation and a thin friable overlying fibrous cap, but they usually appear innocuous on angiography. Effective risk factor modification stabilizes the dangerous plaques and is associated with prompt improvement in endothelial dysfunction and a substantial decrease in the risk of acute cardiovascular events and death.