Cardiac catheterisation and coronary angiography can provide important information about the heart and the surrounding blood vessels supplying it.

This can help diagnose heart conditions, plan future treatments, and carry out certain procedures.

The heart has 4 chambers: the 2 small chambers at the top are called atria and the 2 larger chambers at the bottom are called ventricles.

Each ventricle has 2 valves to control the flow of blood in and out of the ventricle.

Using cardiac catheterisation, your cardiologist (heart specialist) can tell how well your heart valves and chambers are working.

The procedure can also provide important information about the blood pressure inside your heart.

Coronary angiography also gives video images (angiograms) that can show whether the blood vessels surrounding your heart are narrowed or blocked.

You may need treatment if there are any narrow areas or blockages.

Diagnosing heart conditions

Cardiac catheterisation and coronary angiography can be used to help diagnose a number of heart conditions.

These include:

• coronary heart disease (CHD) – where a build-up of fatty substances in the coronary arteries (the arteries that supply blood to the heart) affects the heart's blood supply; CHD can cause heart attacks and angina
• heart attacks – serious medical emergencies where the heart's blood supply is suddenly blocked, usually by a blood clot
• angina – a dull, heavy or tight chest pain caused by a restriction in the heart's blood supply
• congenital heart disease in children – a range of birth defects that affect the normal workings of the heart
• valvular heart disease – problems with the function of 1 or more of the 4 valves within your heart
• cardiomyopathy – diseases of the heart muscle, which are sometimes inherited

Treating heart problems

Coronary angiography is also used before or during certain treatments.

For example, it may be used if you need to have:

• a coronary angioplasty or percutaneous coronary intervention – a procedure to widen blocked or narrowed coronary arteries
• a coronary artery bypass graft (CABG) – surgery to divert blood around narrow or clogged arteries and improve blood flow to the heart
• heart valve surgery – an operation to repair or replace the heart valves

Cardiac catheterisation and coronary angiography is carried out at a hospital or specialist heart centre.

The team responsible for your care may include:

• a cardiologist (heart specialist)
• a nurse
• a cardiac technician
• a radiographer (a specialist in using imaging technology)

The procedure is usually carried out in an X-ray room or a catheterisation laboratory.

Before the procedure

Before the procedure is carried out, you should tell your cardiologist if:

• you have any allergies
• you're taking any medication – either for a heart problem or another medical condition

You'll be told whether to continue taking your medication or if you need to stop.

You shouldn't stop taking prescribed medication unless you're advised to do so.

You may also be asked not to eat or drink anything for a few hours before the procedure.

Anaesthetic

The procedure is usually carried out under local anaesthetic, so you'll be awake while the procedure is carried out, but the area where the catheter is inserted (either the groin or arm) will be numbed.

You may also be given the option of having a sedative. This makes you feel sleepy and relaxed while remaining awake and being aware enough to respond to instructions, such as being asked to take a deep breath and hold it at certain points during the procedure.

General anaesthetic is sometimes used when young children need to have the procedure. This is because they may find it too difficult to stay still while it's being carried out.

Monitoring your heart

You'll be attached to an electrocardiogram (ECG) machine throughout the procedure. An ECG records your heart's rhythms and electrical activity.

A number of electrodes (small metallic discs) are placed on your arms, legs and chest. The electrodes are connected to a machine that records the electrical signals of each heartbeat.

The procedure

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GABRIELLE VOINOT/LOOK AT SCIENCES/SCIENCE PHOTO LIBRARY

If you don't need any further procedures, such as balloon angioplasty, cardiac catheterisation and coronary angiography should take about half an hour.

Here's a step-by-step guide to what you can expect during the procedure.

The healthcare professionals who are with you will explain what's happening.

• After entering the catheterisation laboratory, you'll be asked to lie on a special table. If the catheter is being inserted into your groin, your groin may be shaved and cleansed with antiseptic fluid.
• You'll be covered with a sterile sheet and given an injection of local anaesthetic to numb the skin of your groin or arm, so the procedure shouldn't be painful.
• A small cut (incision) will be made in your groin or arm and a fine tube called a sheath is inserted to hold the blood vessel open.
• The catheter will be moved through your blood vessels and into your heart using X-ray guidance.
• A small amount of dye called contrast medium is injected through the catheter and the pressure in your heart will be measured.
• As the dye is injected, you may feel a hot flushing sensation that passes quickly. You may also experience a warm sensation in your groin that feels as if you have wet yourself, or you may have a metallic taste in your mouth. This is nothing to worry about and you'll be warned when to expect it. 
• You won't feel the catheter being guided through your blood vessels. But you may be aware of the odd missed or extra heartbeat.
• A series of X-ray images are taken of your heart and the blood vessels around it. These are called angiograms and will be stored on a computer.
• In certain circumstances (for example, if your arteries are blocked) your cardiologist may decide to carry out a balloon angioplasty (a procedure to widen blocked arteries). This will be carried out immediately and adds about an extra hour to the procedure. This should have been discussed with you beforehand, unless it's needed as an emergency procedure.
• The catheter and sheath will be removed once the procedure is complete.
• If the catheter was inserted into your groin, the nurse or cardiologist may apply pressure to the entry site for about 10 minutes to stop any bleeding.
• Alternatively, a number of different plugs, stitches or clips may be used to seal or close up the wound.
• If the catheter was inserted through your arm, a tight dressing or cuff may be applied for around 2 to 3 hours.

After having cardiac catheterisation and coronary angiography, your pulse and blood pressure will be checked and recorded.

If the catheter was inserted into your groin, a nurse may apply pressure for up to 10 minutes to stop the bleeding after the catheter and sheath have been removed.

Sometimes the doctor carrying out the procedure inserts a small surgical plug, a special stitch or another closure device to seal the wound. In these cases, it isn't necessary to apply pressure to the wound.

If the catheter was inserted into your arm, a small pressurised cuff may be placed around your arm. The pressure is gradually decreased over the course of several hours.

A nurse will check whether there's any bleeding at the point where the catheter was inserted.

You should be able to sit up straight away and may be able to walk around soon afterwards if the catheter was inserted into your arm. 

But if the catheter was inserted into your groin, you'll be asked to lie flat after any bleeding has stopped.

If all is well, you'll be asked to sit up after a few hours and should be able to get up and walk around shortly after.

You should tell the healthcare professionals treating you if you feel unwell at any time after the procedure.

Going home

Most people are able to go home on the same day the procedure is carried out, although you'll need to arrange a lift home from a family member or friend.

You should also make sure that someone stays with you overnight in case you experience any problems.

Most people feel fine a day or so after having the procedure. You may feel a bit tired, and the wound site is likely to be tender for up to a week.

Any bruising may last for up to 2 weeks.

Recovery advice

You'll be advised about things to do or avoid during your recovery before leaving hospital.

Examples of advice you may be given include:

• Avoid having a bath for a day or two. You can still take a shower, but try to keep the wound as dry as possible.
• If you have a plaster on your groin, it can be removed the day after the procedure and it doesn't usually need to be replaced.
• Don't drive until told that it's safe to do so, which may not be for up to 3 days.
• Avoid playing sport, excessive activity or lifting anything heavy for about 2 days.

Call your GP or NHS 111 if you have concerns about your wound or recovery in general.

When to seek medical advice

Contact your GP if you experience:

• any increase in pain, swelling, redness or discharge at the wound site
• a hard, tender lump (larger than the size of a pea) under the skin around your wound
• a high temperature (fever)
• discolouration, coldness or numbness in the leg or arm on the same side of the body where the catheter was inserted

If you experience any bleeding from your wound, apply pressure to the area.

If the bleeding from your wound doesn't stop or restarts after applying pressure for 10 minutes, dial 999 and ask for an ambulance.

Getting the results

A copy of your angiography results will be sent to your GP and referring specialist (if appropriate).

Depending on the results, you may be advised to:

• take medication to treat your heart condition
• have a coronary angioplasty (a procedure to widen the coronary arteries)
• have heart surgery, such as a coronary artery bypass graft (a surgical procedure to divert blood around clogged arteries)

Cardiac catheterisation and coronary angiography are generally considered to be safe procedures. However, as with all medical procedures, there are some associated risks.

The main risks of coronary angiography include:

• bleeding under the skin at the wound site (haematoma) – this should improve after a few days, but contact your GP if you're concerned
• bruising – it's common to have a bruise in your groin or arm for a few weeks
• allergy to the contrast dye used, causing symptoms such as a rash and a headache – this is uncommon, but you should discuss any allergies with your cardiologist (heart specialist) before having the procedure

Serious complications

In very rare cases, more serious complications of coronary angiography can occur. These include:

• damage to the artery in the arm or groin in which the catheter was inserted, with the blood supply to the limb possibly being affected
• heart attack – a serious medical emergency where the heart's blood supply is suddenly blocked
• stroke – a serious medical condition that occurs when the blood supply to the brain is interrupted
• damage to the kidneys caused by the contrast dye
• tissue damage caused by X-ray radiation if the procedure is prolonged
• death

The risk of a serious complication occurring is estimated to be less than 1 in 1,000. People with serious underlying heart problems are most at risk.

Your cardiologist should discuss the risks with you before the procedure.