Coronary artery disease is caused by the buildup of plaque on the inside of the coronary arteries, the blood vessels that supply oxygen-rich blood to the heart muscle. Plaque is made up of excess cholesterol, calcium, and other substances that float in blood and, over time, build up on the inside walls of the coronary arteries and other arteries.

This process of plaque buildup is called hardening of the arteries, or atherosclerosis. The plaque deposits decrease the space through which blood can flow. Poor blood flow can "starve" the heart muscle and lead to chest pain. A heart attack results when blood flow is completely blocked, usually by a blood clot forming over a plaque that has broken open (ruptured).

Coronary artery disease is treated with lifestyle changes, such as increasing exercise, eating a heart-healthy diet, and stopping smoking. Coronary artery disease also is treated with medications to help reduce high cholesterol, control high blood pressure, and manage other risk factors.