Coronary angiogram: what happens and risks

What does a coronary angiogram show?

A coronary angiogram is an X-ray of the coronary arteries, the blood vessels that supply the heart muscle. These arteries do not show on ordinary X-rays, so dye is used to make them visible.

It helps doctors look for narrowing, blockages and blood flow problems. It is also called cardiac catheterisation.

What happens during the test?

It is done under local anaesthetic. A thin tube called a catheter is passed in through the wrist or groin, and X-ray images guide it to the coronary arteries.

Contrast dye is injected while X-ray images are taken. The test usually takes between 30 minutes and 2 hours.

Is it done through the wrist or the groin?

The cardiologist chooses whether to use the wrist or the groin. The wrist is often used, and the choice affects aftercare.

Wrist access usually means faster recovery and fewer restrictions. With groin access people may need to lie flat for a period afterwards.

What are the risks?

The NHS describes the risk of serious complications as very small. Bruising and a collection of blood under the skin, called a haematoma, where the catheter went in are the most common problems.

A very small risk of more serious problems is listed, including an allergic reaction to the contrast dye, stroke or heart attack.

What is recovery like?

Most people go home the same day. A compression band is often placed on the wrist, or a seal or pressure device on the groin, to close the entry point. Bruising and soreness for a few days or weeks are common.

Leaflets list a growing or painful lump, swelling, redness, discharge, or a cold, pale or painful hand or leg as reasons to seek advice. The ward or the GP can advise, and NHS 111 can help out of hours.

Leaflets say bleeding from the entry site that does not stop with firm pressure needs a 999 call.

What happens if a narrowing is found?

The images show whether arteries are narrowed or blocked. If it is unclear how severe a narrowing is, doctors may measure pressure with a wire in the artery or scan it from inside with a tiny imaging device.

If a blockage is found, treatment such as angioplasty with a stent can sometimes be done at the same time.