Coronary artery disease is the narrowing or blockage of the coronary arteries, usually caused by atherosclerosis. Atherosclerosis (sometimes called “hardening” or “clogging” of the arteries) is the buildup of cholesterol and fatty deposits (called plaques) on the inner walls of the arteries.
Coronary artery disease (CAD) is the most common type of heart disease in the United States. For some people, the first sign of CAD is a heart attack. You and your health care team may be able to help you reduce your risk for CAD.
Causes of CAD
CHD is believed to start with injury or damage to the inner layer of a coronary artery. This damage causes fatty plaque deposits to build up at the site of the injury. These deposits consist of cholesterol and other cellular waste products. The accumulation is called atherosclerosis.
If pieces break off or rupture, platelets will clump in the area, attempting to repair the blood vessel. This clump can block the artery, reducing or blocking blood flow, and leading to a heart attack.
The doctor will ask questions about your medical history, do a physical exam and order routine blood tests. He or she may suggest one or more diagnostic tests as well, including:
- Electrocardiogram (ECG). An electrocardiogram records electrical signals as they travel through your heart. An ECG can often reveal evidence of a previous heart attack or one that’s in progress.
In other cases, Holter monitoring may be recommended. With this type of ECG, you wear a portable monitor for 24 hours as you go about your normal activities. Certain abnormalities may indicate inadequate blood flow to your heart.
- Echocardiogram. An echocardiogram uses sound waves to produce images of your heart. During an echocardiogram, your doctor can determine whether all parts of the heart wall are contributing normally to your heart’s pumping activity.
Parts that move weakly may have been damaged during a heart attack or be receiving too little oxygen. This may indicate coronary artery disease or various other conditions.
- Stress test. If your signs and symptoms occur most often during exercise, your doctor may ask you to walk on a treadmill or ride a stationary bike during an ECG. This is known as an exercise stress test. In some cases, medication to stimulate your heart may be used instead of exercise.
Some stress tests are done using an echocardiogram. For example, your doctor may do an ultrasound before and after you exercise on a treadmill or bike. Or your doctor may use medication to stimulate your heart during an echocardiogram.
Doctors may also use medications to stimulate your heart during an MRI. Doctors may use this imaging test to evaluate you for coronary artery disease.
Another stress test known as a nuclear stress test helps measure blood flow to your heart muscle at rest and during stress. It’s similar to a routine exercise stress test but with images in addition to an ECG. A tracer is injected into your bloodstream, and special cameras can detect areas in your heart that receive less blood flow.
- Cardiac catheterization and angiogram. To view blood flow through your heart, your doctor may inject a special dye into your coronary arteries. This is known as an angiogram. The dye is injected into the arteries of the heart through a long, thin, flexible tube (catheter) that is threaded through an artery, usually in the leg, to the arteries in the heart.
This procedure is called cardiac catheterization. The dye outlines narrow spots and blockages on the X-ray images. If you have a blockage that requires treatment, a balloon can be pushed through the catheter and inflated to improve the blood flow in your coronary arteries. A mesh tube (stent) may then be used to keep the dilated artery open.
- Heart scan. Computerized tomography (CT) technologies can help your doctor see calcium deposits in your arteries that can narrow the arteries. If a substantial amount of calcium is discovered, coronary artery disease may be likely.
A CT coronary angiogram, in which you receive a contrast dye injected intravenously during a CT scan, also can generate images of your heart arteries.
Reducing Your Risk for CAD
If you have CAD, your health care team may suggest the following steps to help lower your risk for heart attack or worsening heart disease:
- Lifestyle changes, such as eating a healthier (lower sodium, lower fat) diet, increasing physical activity, and quitting smoking.
- Medications to treat the risk factors for CAD, such as high cholesterol, high blood pressure, an irregular heartbeat, and low blood flow.
- Surgical procedures to help restore blood flow to the heart.