Cardiac catheterisation is an invasive diagnostic procedure that provides important information about the structure and function of the heart.
It usually involves taking X-ray pictures of the heart's arteries (coronary arteries) using a technique called coronary angiography or arteriography. The resulting images are known as coronary angiograms or arteriograms.
Why do I need coronary angiography?
Coronary angiography can be used to help diagnose heart conditions, help plan future treatments and carry out certain procedures. For example, it may be used:
after a heart attack – where the heart's blood supply is blocked
to help diagnose angina – where pain in the chest is caused by a restricted blood supply to the heart
to plan interventional or surgical procedures – such as a coronary angioplasty, where narrowed or blocked blood vessels are widened
Coronary angiography is also considered to be the best method of diagnosing coronary heart disease (where a build-up of fatty substances in the coronary arteries affects the heart's blood supply).
What happens during coronary angiography?
During the procedure, a long, thin and flexible tube called a catheter is inserted into a blood vessel in your groin or arm. Using X-ray images as a guide, the tip of the catheter is passed up to the heart and coronary arteries.
A special type of dye called contrast medium is injected into the catheter and X-ray images (angiograms) are taken.
The contrast medium is visible on the angiograms, showing the blood vessels that the fluid travels through. This clearly highlights any blood vessels that are narrowed or blocked.
The procedure is usually carried out under local anaesthetic, so you will be awake while the procedure is carried out, but the area where the catheter is inserted will be numbed.
After coronary angiography
You will usually be able to leave hospital on the same day you have a coronary angiography after a period of rest and observation.
Most people feel fine a day or so after having the procedure, although you may feel a bit tired afterwards and the wound site is likely to be tender for up to a week. Any bruising may last for several weeks.
You will usually be advised to avoid certain activities, such as bathing, driving and lifting heavy objects, for a day or two after the procedure.
While you are recovering, it's important to look out for signs of any problems. You should seek immediate medical attention if swelling at the site of your wound gets worse, or if you experience excessive bleeding or circulation problems in your limbs.
Cardiac catheterisation and coronary angiography are usually very safe. However, as with all procedures there are some risks, including:
being allergic to the contrast dye – this is uncommon, but you should discuss any allergies that you have with your cardiologist (heart specialist) before having the procedure
bleeding under the skin where the catheter was inserted – this should stop after a few days, but you should contact your GP if you are concerned about it
a very small risk of more serious complications, including damage to the artery in the arm or leg where the catheter was inserted, heart attack, stroke, kidney damage and, very rarely, death
cardiac catheterisation and coronary angiography are used
Cardiac catheterisation and coronary angiography can provide important information about the heart and the blood vessels that surround and supply it.
This can help diagnose heart conditions, help plan future treatments and carry out certain procedures.
The heart has four chambers: the two small chambers at the top are called atria and the two larger chambers at the bottom are called ventricles. Each ventricle has two 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
Coronary angiography can be used to help diagnose a number of heart conditions, including:
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
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 – 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
How cardiac catheterisation and coronary angiography are performed
Cardiac catheterisation and coronary angiography will be carried out at a hospital or specialist heart centre.
The team responsible for your care will usually include a cardiologist (heart specialist), nurse, cardiac technician and a radiographer (a specialist in using imaging technology).
The procedure will usually be 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 and if you are taking any medication, either for a heart problem or another medical condition.
You will be told whether to continue taking your medication or if you need to stop. You should not stop taking prescribed medication unless you are advised to do so.
You may also be asked not to eat or drink anything for a few hours before the procedure.
The procedure will be carried out under local anaesthetic, so you will 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 to make 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 because they may find it too difficult to stay still while it is being carried out.
Monitoring your heart
You will 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.
Provided that you do not need to have a further procedure such as balloon angioplasty, cardiac catheterisation and coronary angiography should take about half an hour.
Below is a step-by-step guide to what you can expect during the procedure. The healthcare professionals who are with you will explain what is happening.
After entering the catheterisation laboratory, you will 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 will 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 should not be painful.
A small cut (incision) will be made in your groin or arm and a fine tube called a sheath will be 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 will be 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 will be warned when to expect it.
You will not feel the catheter being guided through your blood vessels. However, you may be aware of the odd missed or extra heartbeat.
A series of X-ray images will be 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 (an interventional procedure to widen blocked arteries). This will be carried out immediately and will add about an extra hour to the procedure. This usually should have been discussed with you beforehand, unless it is required 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 or clips may be used to seal or close up the wound.
If the catheter was inserted through your arm, a tight dressing will be applied for around two to three hours.
Illustration of coronary angiography
Catheter in arm
Catheter in groin
Recovering from cardiac catheterisation and coronary angiography
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 will insert a small surgical plug to seal the wound or a special stitch or other closure device. In these cases it will not be 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 and the pressure will gradually be decreased over the course of several hours. A nurse will check whether there is any bleeding at the point where the catheter was inserted.
You should be able to sit up straight away and you may be able to walk around soon afterwards if the catheter was inserted into your arm.
However, if the catheter was inserted into your groin, you will be asked to lie flat after any bleeding has stopped. If all is well, you will be asked to sit up after a few hours and you 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.
Most people are able to go home on the same day the procedure is carried out, although you will 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 two weeks.
You will 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.
Do not drive until advised that it is safe to do so, which may not be for up to three days.
Avoid playing sport, excessive activity or lifting anything heavy for about two days.
When to seek medical advice
Contact your GP if you experience:
any increase in pain, swelling, redness and/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 (an interventional 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)
Risks of cardiac catheterisation and coronary angiography
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 are concerned
bruising – it is 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 that you have with your cardiologist (heart specialist) before having the procedure
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
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 you have the procedure.