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 narrowed. It can also show where they are narrowed and by how much.

During the test, a thin tube called a catheter is placed in an artery of your wrist or groin. It's then gently threaded up into your heart. A dye is put through the catheter. The dye helps your doctor see the arteries on the X-ray.

Before the test, you may get medicine that relaxes you or puts you in a light sleep. The area being worked on will be numb. You may feel a brief sting or pinch from the numbing medicine. You may feel some pressure when the doctor puts in the catheter. You will probably feel some warmth when the dye is put in.

The procedure will take about 1 to 3 hours. You may be able to go home later the same day. Some people need to stay in the hospital overnight. You will need to avoid strenuous activity until your doctor says it is okay. This may be for several days.

Coronary artery disease occurs when fatty deposits called plaque (say "plak") build up inside the coronary arteries. These arteries wrap around the heart and supply it with blood and oxygen. When plaque builds up, it can narrow the arteries. This may limit how much blood can get to your heart muscle. If the plaque breaks apart, a blood clot could cause a heart attack.

Narrowing of the arteries can lead to symptoms of angina, such as chest pain or pressure and shortness of breath.

Treatment of coronary artery disease helps relieve symptoms. It also can slow how quickly the disease gets worse and can prevent a heart attack. Treatments include medicines, a heart-healthy lifestyle, angioplasty, and coronary artery bypass surgery. Everyone who has heart disease needs to take medicines and have a heart-healthy lifestyle—even if they have angioplasty or surgery.

An angiogram can help you and your doctor decide what treatment is best for you.

You may decide to have an angiogram because:^{footnote 2}

• It can help your doctor see if a change in treatment might lower your risk of heart attack or death from heart problems. An angiogram can show your doctor where plaques have narrowed your arteries and if blood flow is slowed. But it can't show if these plaques will cause a heart attack.
• You want more relief from your angina. The test can show your doctor if a procedure or surgery could improve your symptoms.

It's important to talk with your doctor about your angina symptoms. Do your symptoms limit your daily activities and make it hard to enjoy your life? Do you have angina during light physical activity, such as walking a couple of blocks or up stairs? Also, if you are taking medicine for angina, let your doctor know if it doesn't control your symptoms enough. Your doctor may change your dose or suggest a different medicine.

Having the test doesn't mean that you will have an angioplasty or bypass surgery.

But, if during the angiogram the doctor sees that your arteries are narrowed, angioplasty could be done right away. So before you have an angiogram, talk with your doctor about a possible angioplasty. During the test, you may not be able to decide about more treatment, because you might be sleepy from medicines.

An angiogram isn't right for everyone.^{footnote 2}

• Other tests may give you and your doctor all the information you need to make treatment decisions. These other tests do not have the risks of an angiogram.
• It's usually not suggested if you have a low risk of a heart attack or you don't have angina symptoms.
• If you can control your angina with medicines and a heart-healthy lifestyle, this test likely will not lead to changes in your treatment.
• You might choose not to have the test if you already know that you don't want to have angioplasty or bypass surgery.

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

Heart attack and stroke happen rarely, but they can be life-threatening. They are more likely to occur in older people or people who have health conditions that raise the risk of heart attack or stroke.

Other problems that can happen during or soon after an angiogram include:

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

Conditions that can raise risk of problems

Certain health conditions can raise your risk of having problems after angioplasty. Conditions that can raise the risk of death from the procedure include heart failure, heart valve problems, and chronic kidney disease. The risk of heart attack may be higher if you have heart disease in the left main coronary artery.

Having these conditions doesn't mean that you will have a problem from the procedure. You and your doctor can talk about whether your risk of a problem is higher than average.

Radiation risk

There is always a slight risk of damage to cells or tissues from being exposed to any radiation. This includes the low levels of X-ray used for this test.

Ask your doctor about your risk of radiation from this test. Talk about whether you feel the benefits of the test might outweigh the risks.

Benefits

The benefits of an angiogram aren't the kinds of things that can be directly measured by numbers. The main reason to think about having the test is that it can help you and your doctor make better decisions about whether and how to treat your heart disease.

Risks

Fewer than 1 out of 100 people have a stroke, bleed heavily, or die soon after a coronary angiogram.^{footnote 1} This means that more than 99 out 100 people do not have these problems. These numbers are based on observed rates of complications from patients, not from studies.