Atherosclerosis, or hardening of the arteries, is an inflammatory process that may cause a number of diseases. The diseases stem from the loss of normal function of the blood vessels caused by the presence of the atheromatous mass or plaque that progressively encroaches on the lumen of the artery. The ensuing loss of function results in the inability to provide an adequate flow of blood to a particular downstream organ, a circumstance called ischemia. The discomfort associated with intermittent and recurrent ischemia of the heart is called angina pectoris, or simply angina.