Depending on the complexity of the investigation, angiography can take between 30 minutes and two hours.

You'll usually be allowed to go home on the same day, although in some cases you may need to stay in hospital overnight.

Angiography is usually a planned procedure. However, it may occasionally be carried out as an emergency – for example, in the case of a heart attack.

For a planned angiography you're likely to have an initial appointment to discuss your health. For example, you may be asked:

• about your medical history
• whether you have any allergies
• whether you're currently taking any medication

You may also have a number of standard tests before having an angiography, including a physical examination and blood tests to check how well organs, such as your kidneys or liver, are working.

Some people choose to take a sedative to help them relax. In this case, you'll be asked not to eat for several hours before the procedure.

The procedure

Most angiography procedures are carried out using local anaesthetic to numb the area where the catheter is going to be inserted. General anaesthetic is sometimes used for young children.

The procedure will be carried out by a specialist, such as a cardiologist (a doctor who specialises in heart disease) or a radiologist (a doctor who specialises in using imaging studies). A nurse may also be present to assist with the procedure.

An intravenous (IV) line will be inserted into a vein in your arm. It can be used to deliver sedatives or any other medication as required. Electrodes (small, metallic discs) may be placed on your chest to record your heartbeat. A blood pressure monitor may also be attached to your arm.

A small plastic tube called a sheath will be placed into one of your arteries. A catheter (a long, thin flexible tube) is inserted through the sheath and on to the arteries being examined. Depending on the area being examined, the catheter is usually inserted into an artery in your wrist or groin.

X-rays are used to help guide the catheter to the right place. Contrast dye will then be injected through the catheter and a series of X-rays will be taken. This will allow a map of the arteries to be created.

The procedure isn't painful but you may feel a slightly warm sensation, or a mild burning sensation, as the contrast dye moves through your blood vessels. It can take between 30 minutes and two hours to complete the procedure, depending on the complexity of your condition and what the radiologist finds.

In some cases, other procedures can be carried at the same time, such as inserting a balloon or a small tube called a stent through the catheter to open up a narrowed artery. This is known as angioplasty.

Once the procedure has been completed, the catheter is removed and the incision is closed using manual pressure, a plug or a clamp.

Afterwards

Following angiography, you'll be taken to a recovery ward. You'll be asked to lie still for a few hours, to prevent bleeding at the site of the incision.

Most people are able to leave hospital on the same day as the procedure. However, occasionally, it may be necessary for you to stay in overnight for observation. You'll be able to eat and drink as soon as you feel ready to, but it may take eight to 12 hours before you're well enough to resume normal activities.

Depending on what the cardiologist or radiologist finds during the angiography, they may be able to discuss your results with you shortly after the procedure. Alternatively, they may write a report and send it to your GP.