An angiogram is an X-ray test that uses a special dye and camera (fluoroscopy) to take pictures of the blood flow in an artery (such as the aorta) or a vein (such as the vena cava). An angiogram can be used to look at the arteries or veins in the head, arms, legs, chest, back, or belly.
Common angiograms can look at the arteries near the heart (coronary angiogram), lungs (pulmonary angiogram), brain (cerebral angiogram), head and neck (carotid angiogram), legs or arms (peripheral), and the aorta (aortogram).
During an angiogram, a thin tube called a catheter is placed into a blood vessel in the groin (femoral artery or vein) or just above the elbow (brachial artery or vein). The catheter is guided to the area to be studied. Then an iodine dye (contrast material) is injected into the vessel to make the area show clearly on the X-ray pictures. This method is known as conventional or catheter angiogram. The angiogram pictures can be made into regular X-ray films or stored as digital pictures in a computer.
An angiogram can find a bulge in a blood vessel (aneurysm). It can also show narrowing or a blockage in a blood vessel that affects blood flow. An angiogram can show if coronary artery disease is present and how bad it is.
A magnetic resonance angiogram (MRA) or computed tomography angiogram (CTA) may be an option instead of an angiogram. Each of these tests is less invasive than a standard angiogram. Some MRA tests and all CTA tests require an injection of dye. A CTA also involves radiation exposure.
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Why It Is Done
An angiogram is done to:
- Detect problems with blood vessels that affect blood flow. Examples of such problems include a tear in a blood vessel (which can cause blockage or internal bleeding), aneurysms (which are weaknesses in the blood vessel wall), and narrowed areas.
- Look for changes in the blood vessels of injured or damaged organs.
- Show the pattern of blood flow to a tumour. This can not only help show how much the tumour has spread but also guide treatment.
- Show the condition, number, and location of renal arteries before a kidney transplant.
- Look for a source of bleeding, such as an ulcer.
- Prepare for surgery on diseased blood vessels of the legs (peripheral arterial disease) in people who have severe leg pain when walking.
- Check how bad atherosclerosis is in the coronary arteries.
In some cases, a method called interventional radiology may be used during an angiogram to treat diseases. For example, a catheter can be used to open a blocked blood vessel, deliver medicine to a tumour, or stop intestinal bleeding caused by diverticular hemorrhage. To stop intestinal bleeding, the catheter is moved into the small artery where the bleeding is occurring, and medicine that narrows the artery or causes the blood to clot is injected through the catheter.
How To Prepare
Before an angiogram, tell your doctor if you:
- Are or might be pregnant.
- Are breastfeeding. Use formula (throw out your breast milk) for 1 to 2 days after the angiogram until the dye has passed from your body. This generally takes 24 hours.
- Are allergic to iodine dye used in the test.
- Have ever had a serious allergic reaction (anaphylaxis) from any substance, such as the venom from a bee sting or from eating shellfish.
- Have asthma.
- Are allergic to any medicines.
- Have any bleeding problems or are taking blood-thinning medicines.
- Have a history of kidney problems or diabetes, especially if you take metformin (such as Glucophage) to control your diabetes. The dye used during an angiogram can cause kidney damage in people who have poor kidney function.
Do not eat or drink for 4 to 8 hours before the angiogram. You may be asked to not take aspirin, aspirin products, or blood thinners for several days before the test and for 1 day after the test. If you take these medicines, talk with your doctor.
An angiogram can be done as an in-patient or outpatient. If you are an outpatient, you will stay in a recovery room for several hours before you go home. You may want to bring something to do or read to pass the time. Arrange to have someone take you home because you may get a sedative before the test. If you stay overnight in the hospital, you will probably go home the next day.
The test may take several hours, so you will empty your bladder just before it begins.
Also before the angiogram you may have other blood tests, such as blood clotting (coagulation) studies, blood urea nitrogen (BUN), and creatinine.
You will be asked to sign a consent form that says you understand the risks of the test and agree to have it done.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form .
How It Is Done
You will need to take off any jewellery. You may need to take off all or most of your clothes. You will be given a gown to wear during the test.
During the test
You will likely have an intravenous (IV) line in a vein in your arm so your doctor can give you medicine or fluids if needed. A device called a pulse oximeter, which measures oxygen levels in your blood, may be clipped to your finger or ear. Small pads or patches (electrodes) are placed on your arms, chest, or legs to record your heart rate and rhythm.
You will lie on your back on an X-ray table. Ask for a pad or blanket to make yourself comfortable. A strap, tape, or sandbags may be used to hold your body still. A lead apron may be placed under your genital and pelvic areas to protect them from X-ray exposure.
A round cylinder or rectangular box that takes the pictures during fluoroscopy will be moved above you. The fluoroscope will move under you during the test.
The place where the catheter will be inserted (in the groin or above the elbow) will be shaved and cleaned. Your doctor will freeze the area with a local anesthetic. Then he or she will put a needle into the blood vessel. A guide wire will be put through the needle into the blood vessel and the needle will be removed. The catheter will be placed over the guide wire and moved into the blood vessel. The catheter then will be guided through the blood vessels until the tip is in the area to be studied. Your doctor will use the fluoroscope to watch the movement of the catheter in the blood vessels.
When the catheter is in place, the dye is injected through it. You may be asked to take a breath and hold it for several seconds. Several X-ray pictures will be taken one after another. These will be available right away for your doctor to look at. You need to lie very still so the pictures are clear. More pictures may be taken.
After the test
An angiogram takes 1 to 3 hours. The catheter is taken out after the angiogram, and pressure is put on the needle site for 10 to 15 minutes to stop any bleeding. A bandage or compression device is put on the site. This will prevent bleeding. You will be given pain medicine if you need it.
If the catheter was put in your groin, you will need to lie still and keep your leg straight for several hours. The nurse may put a weighted bag on your leg to keep it still. If the catheter was put in your arm, you may be able to sit up and get out of bed right away. But you will need to keep your arm still for at least 1 hour.
Your doctor will give you specific instructions after the test. You can use an ice pack on the needle site to relieve pain and swelling.
The place in your hands and feet where your heartbeat (peripheral pulse) can be felt may be marked with a pen. Your pulse may be checked before and after the angiogram.
How It Feels
You may feel a brief sting or pinch from the freezing medicine. Most people do not have pain when the catheter is in the blood vessel.
You may feel pressure in the blood vessel as the catheter is moved. Let your doctor know if you are having pain.
You will probably feel some warmth when the dye is put in. This feeling lasts only a few seconds. For some people, the feeling of heat is strong and for others it is very mild.
You may have a headache, flushing of the face, or a salty or metallic taste in your mouth after the dye is used. These feelings do not last long. Some people may feel sick to their stomachs or may vomit, but this is not common.
After the test, you may have some tenderness and bruising at the site where the catheter was inserted.
You can drink extra fluids to pass the dye from your body unless your doctor has told you not to.
The chance of any major problem from an angiogram is very small, but some problems can occur. In most cases, the problems occur within 2 hours after the test when you are in the recovery room. If the problem occurs during the angiogram, the test may not be completed. You may need urgent treatment that could include surgery.
- There is a chance of an allergic reaction to the iodine dye. The reaction can be mild (itching, rash) or severe (trouble breathing or sudden shock). Most reactions can be treated with medicines. Be sure to tell your doctor if you have hay fever, asthma, or iodine allergy or food allergies.
- There is a small chance that the catheter may damage a blood vessel or dislodge a piece of clotted blood or fat from the vessel wall. The clot or fat can block blood flow to the brain, arm, leg, or intestine (bowel).
- Bleeding from the needle site may occur. Also, a blood clot can form where the catheter was inserted. This may cause some blockage of the blood flow in the arm or leg.
- The iodine dye used for the test can cause water loss or direct damage to the kidneys. This is a special concern for people who have kidney problems, diabetes, or who are dehydrated. Special measures are used during the test to prevent problems for people who need an angiogram and have these conditions.
- There is always a small chance of damage to cells or tissue from being exposed to any radiation, even the low level used for this test.
An angiogram is an X-ray test that uses a special dye and camera (fluoroscopy) to take pictures of the blood flow in an artery (such as the aorta) or a vein (such as the vena cava). Your doctor may tell you some results right after the test. Full results are usually ready the same day.
The blood vessels are normal in shape, size, location, and number.
The dye flows evenly through the blood vessels.
No narrowing, blockage, bulging, or other problem of the blood vessels is seen.
Blood vessels that are not in their normal position may mean that a tumour or other growth is pushing against them.
A narrow spot in an artery may mean that a fat deposit, calcium deposit, or clot is reducing blood flow through the blood vessel.
A bulge in a blood vessel may mean a weakness in the blood vessel wall ( aneurysm).
Dye that leaks out of a blood vessel may mean a hole in the blood vessel.
There is abnormal branching of blood vessels present since birth (congenital).
An abnormal pattern of blood vessels may mean that a tumour is present.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
- Being pregnant. An angiogram is not usually done during pregnancy because the radiation could damage the developing baby (fetus).
- Blockage or curving of the blood vessels caused by atherosclerosis, high blood pressure, or aging. This may make it hard to guide the catheter through the blood vessels or hard to inject the dye.
- Not being able to lie still during the test.
What To Think About
- A magnetic resonance angiogram (MRA) or computed tomography angiogram (CTA) may be an option instead of an angiogram. Each of these tests is less invasive than a standard angiogram. Some MRA tests and all CTA tests require an injection of dye. A CTA also involves radiation exposure. Some surgeons may want results from a standard angiogram before doing surgery to repair a damaged or abnormal blood vessel.
- For people with kidney problems, diabetes, or dehydration, steps are taken to prevent kidney damage. Less dye may be used or more fluids may be given before, during, and after the test. If you have a history of kidney problems, other blood tests (creatinine, blood urea nitrogen) may be done before an angiogram to make sure that your kidneys are working well.
- In rare cases, surgery may be needed to repair a hole in the blood vessel where the catheter was placed. There is also a substance that can be used to help plug the hole in the vessel and stop the bleeding. The substance used to plug the hole in the vessel is normally absorbed by the body over several months.
Other Works Consulted
- Bluemke, D, et al. (2008). Noninvasive coronary artery imaging: Magnetic resonance angiography and multidetector computed tomography angiography. A scientific statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young. Circulation, 118: 586–606.
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
- Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Current as of: December 9, 2019
Author: Healthwise Staff
Medical Review: Rakesh K. Pai, MD - Cardiology, Electrophysiology
Brian O'Brien, MD, FRCPC - Internal Medicine
Adam Husney, MD - Family Medicine
Martin J. Gabica, MD - Family Medicine
E. Gregory Thompson, MD - Internal Medicine
Howard B. Schaff, MD - Diagnostic Radiology
Current as of: December 9, 2019
Author: Healthwise Staff
Medical Review:Rakesh K. Pai, MD - Cardiology, Electrophysiology & Brian O'Brien, MD, FRCPC - Internal Medicine & Adam Husney, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & Howard B. Schaff, MD - Diagnostic Radiology