Coronary angiogram

Doctors looking away

An angiogram (also known as a cardiac catheterisation) is a special type of x-ray which uses contrast dye to allow your doctor to look at your coronary arteries (the blood vessels that supply your heart).

The dye lets your doctor see how well the blood is flowing and shows up any narrowings.

Depending on your results, the procedure can help your doctor decide what treatment you might need.

An angiogram can sometimes also be helpful for investigating other conditions, such as congenital heart disease.

What happens during an angiogram?

The test is done in a cardiac catheter laboratory or ‘cath lab’. You can expect the test to last around half an hour, although it can sometimes take longer. You will need to lie flat for the procedure.

  • You will be asked not to eat or drink anything for a few hours before your procedure.
  • You’ll be given a local anaesthetic injection in the wrist or groin. The catheter (a thin, flexible tube) will then be passed into an artery.
  • The catheter will be directed through your blood vessels and up to your heart. The doctors will use X-ray to help guide them to the arteries.
  • A special dye called contrast will then be passed through the catheter and a series of images will be taken. It is very common to feel a hot, flushing sensation as the dye enters your bloodstream, but this is completely normal and only lasts for a few seconds. The dye will show up any narrowed areas or blockages in the artery on the X-ray.
  • During your procedure, you’ll be attached to a heart monitor that records your heart rate and rhythm and you’ll have a probe measuring your oxygen levels on your finger. If you feel unwell or uncomfortable at any time, you should tell a member of the hospital staff.

What happens after an angiogram?

After the procedure, the catheter will be removed and a collagen plug called an angioseal will be left in place. This is common if the procedure is performed through the groin. You will need to stay on bedrest for about an hour. Some doctors prefer to apply a pressure pad to the wound, in which case you will need to stay on bedrest a bit longer, usually around 4 hours.  

If your procedure is performed through your wrist, a pressure device to reduce the risk of bleeding is left in place and the nurses will gradually reduce the pressure over a short period of time then remove it altogether. You will be able to sit in a chair almost straight away.

The nurses will check your blood pressure and pulse and keep an eye on your wound. It is important to drink plenty of fluid as this helps to flush the dye out of your system.

As long as you feel well, you should be able to go home the same day, although this may depend on the results. Your doctor will explain these to you before you leave.

The most common after-effect is bruising at the site where the catheter was inserted which may feel tender and numb for a few days. You might feel tired, but you should be back to normal within a few days. If you are worried about any of the after-effects, contact your doctor.

Some people who have a coronary angiogram go on to have a treatment called coronary angioplasty.

What is a CT coronary angiogram?

CT stands for ‘computerised tomography’. A CT scan is a modern, sophisticated type of X-ray.

A CT coronary angiogram shows the blood flow through the coronary arteries. For this test the dye is injected into a small vein in your arm. This makes the test less invasive than a traditional angiogram. 

You will then lie on a bed which passes through a doughnut-shaped opening in a CT scanner to show detailed images of your heart. Some people feel a bit claustrophobic during this test, so let the team know if you feel nervous.

A CT coronary angiogram is generally not as reliable at detecting narrowings in small coronary arteries or in small branches as a traditional coronary angiogram. This means that the standard coronary angiogram is still the ‘gold standard’ for diagnosing coronary heart disease.

What are the risks of having an angiogram?

An angiogram is a relatively safe, very common test. Serious complications are rare and your doctor will discuss these before you have it done.

Following an angiogram, some people may develop a collection of blood under the skin, which is called a haematoma. This can be uncomfortable and cause bruising, but it should go down after a few days. However, contact your doctor if you have any concerns.

A small amount of radiation is used during an angiogram. The doctor will bear this in mind if you have been exposed to higher levels than normal.

Want to know more?

Order or download our publications:

Tests booklet