A coronary angiogram is an X-ray test that takes pictures of the blood flow through your coronary arteries. It helps your doctor see if your arteries are clogged, where they are clogged, and by how much. An angiogram helps you and your doctor decide what treatment is best for your coronary artery disease. Treatments include medicines, angioplasty, and coronary artery bypass surgery.

During an angiogram, a thin tube called a catheter is placed in an artery of your arm or leg and gently threaded up into your heart. A special dye goes through the catheter. The dye helps the arteries show up on the X-ray. The doctor checks the X-rays to see if your coronary arteries are clogged or blocked.

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 limits how much blood can get to your heart.

Coronary artery disease can occur slowly over time without your knowing it. You may not have any symptoms until the arteries are very narrow. Symptoms include angina, such as chest pain or pressure, and shortness of breath.

Without treatment, coronary artery disease can lead to serious problems, such as a heart attack or a stroke.

Your doctor is likely to suggest that you adopt healthy habits such as quitting smoking, eating a heart-healthy diet, and getting regular exercise. By doing these things, you can slow the spread of the disease and improve your quality of life.

You may need to take medicines to lower your cholesterol or high blood pressure. Your doctor may prescribe aspirin to reduce your risk of heart attack. And he or she may prescribe other medicines to control angina, if you have it.

If lifestyle changes and medicines don't work well enough to relieve your symptoms and lower your risk for a heart attack, you may need to have angioplasty or bypass surgery.

If during the angiogram the doctor sees that your arteries are badly blocked, you may need angioplasty or bypass surgery right away. You may want to talk with your doctor about these treatments before you have an angiogram. During the test, you will not be able to decide about more treatment, because you will be sleepy from medicines.

Most people do not have serious problems during or after an angiogram.

Serious problems, such as heart attack and stroke, are rare but can be life-threatening. They are more likely to occur in some people, such as people who are critically ill or elderly.

Less serious problems may include:

• A tear or sudden closure in an artery.
• Allergic reaction to the dye used to see the coronary arteries.
• Kidney damage related to the dye.
• Bleeding or bruising where the catheter was inserted.

Radiation risk. There is always a slight risk of damage to cells or tissues from being exposed to any radiation, including the low levels of X-ray used for this test. But the risk of damage from the X-rays is usually very low compared with the potential benefits of the test.

*Based on the best available evidence (evidence quality: borderline)

Benefits

The benefits of an angiogram aren't the kinds of things that can be directly measured by numbers. The main reason to consider having the test is that it can help you and your doctor make better decisions about whether and how to treat your heart disease. In some cases, those treatment decisions can be life-saving.

Risks

The quality of evidence about risks is borderline.

Take a group of 1,000 people who have an angiogram . They are at risk for several rare but serious risks, including:

• Heart attack: 1 person out of 1,000 may have a heart attack related to the procedure. This means that 999 probably won't.
• Stroke:1 person out of 1,000 may have a stroke related to the procedure. This means that 999 probably won't.
• Serious bleeding at the site where the tube is placed: 10 to 40 people out of 1,000 may have serious bleeding. This means that 960 to 990 probably won't.
• Death: 1 to 2 out of 1,000 may die as a result of the procedure. This means that 998 to 999 probably won't.

Understanding the evidence

Some evidence is better than other evidence. Evidence comes from studies that look at how well treatments and tests work and how safe they are. For many reasons, some studies are more reliable than others. The better the evidence is—the higher its quality—the more we can trust it.

The information shown here is based on the best available evidence.^{1, 2, 3, 4, 5, 6, 7, 8} The evidence is rated using four quality levels: high, moderate, borderline, and inconclusive.

Another thing to understand is that the evidence can't predict what's going to happen in your case. When evidence tells us that 2 out of 100 people who have a certain test or treatment may have a certain result and that 98 out of 100 may not, there's no way to know if you will be one of the 2 or one of the 98.

Your doctor may suggest that you have this test if:

• A cardiac stress test suggests that you have severe heart disease. This test checks for changes in your heart while you exercise.
• You have angina symptoms while you are at rest or during only moderate physical activity. Or you are taking medicines for angina but they don't control it.
• You have another heart problem, such as heart failure, that may be caused by heart disease.

You probably do not need an angiogram if you can control your angina and other symptoms with medicines and lifestyle changes and if you are otherwise healthy.