Heart Disease Health Center

What is coronary artery disease?

Coronary artery disease occurs when fatty deposits called plaque (say "plak") build up inside the coronary arteries. The coronary arteries wrap around the heart and supply it with blood and oxygen. When plaque builds up, it narrows the arteries and reduces the amount of blood that gets to your heart. This can lead to serious problems, including heart attack.

Coronary artery disease (also called CAD) is the most common type of heart disease. It is also the number one killer of both men and women in the United States.

It can be a shock to find out that you have coronary artery disease. Many people only find out when they have a heart attack. Whether or not you have had a heart attack, there are many things you can do to slow coronary artery disease and reduce your risk of future problems.

What causes coronary artery disease?

Coronary artery disease is caused by hardening of the arteries, or atherosclerosis. Atherosclerosis occurs when plaque builds up inside the arteries. (Arteries are the blood vessels that carry oxygen-rich blood throughout your body.) Atherosclerosis can affect any arteries in the body. When it occurs in the arteries that supply blood to the heart, it is called coronary artery disease.

Plaque is a fatty material made up of cholesterol, calcium, and other substances in the blood. To understand why plaque is a problem, compare a healthy artery with an artery with atherosclerosis:

• A healthy artery is like a rubber tube. It is smooth and flexible, and blood flows through it freely. If your heart has to work harder, such as when you exercise, a healthy artery can stretch to let more blood flow to your body's tissues.
• An artery with atherosclerosis is more like a clogged pipe. Plaque narrows the artery and makes it stiff. This limits the flow of blood to the tissues. When the heart has to work harder, the stiff arteries can't flex to let more blood through, and the tissues don't get enough blood and oxygen.

See a picture of a normal artery and an artery narrowed by plaque .

When plaque builds up in the coronary arteries, the heart doesn't get the blood it needs to work well. Over time, this can weaken or damage the heart. If a plaque tears, the body tries to fix the tear by forming a blood clot around it. The clot can block blood flow to the heart and cause a heart attack. See a picture of how plaque causes a heart attack .

What are the symptoms?

Usually people with coronary artery disease don't have symptoms until after age 50. Then they may start to have symptoms at times when the heart is working harder and needs more oxygen, such as during exercise. Typical first symptoms include:

• Chest pain or discomfort, called angina (say "ANN-juh-nuh" or "ann-JY-nuh").
• Shortness of breath.
• Heart attack. Too often, a heart attack is the first symptom of coronary artery disease.