Coronary artery disease (CAD) is one type of heart disease that occurs when the blood vessels that supply blood to the heart muscle (coronary arteries) are narrowed or blocked. This narrowing or blockage is most often caused by the buildup of fat (cholesterol) and calcium inside the walls of the arteries leading to the heart. This process is called atherosclerosis, or hardening of the arteries. The buildup of fat and calcium inside the arteries is called a plaque.

• Plaque may narrow the arteries, reducing blood flow to the heart muscle. If blood flow to the heart is reduced, a person may have chest pain (angina).
• A plaque may suddenly rupture or tear open, causing a blood clot to form in an artery. When blood flow to the heart muscle is blocked for an extended period of time, this sometimes results in a heart attack (myocardial infarction).

Coronary artery disease is the leading cause of death in the United States.