A Cardiac Catheterisation is sometimes carried out to confirm the exact nature of a heart defect if the results from an echocardiogram provide insufficient detail to decide on treatment. The procedure can also be used to treat some conditions, for instance to close small holes, stretch a narrow blood vessel or even replace a valve, thus avoiding the need for open heart surgery.
How it is done
Catheterisation is carried out either using a local anaesthetic under sedation, or else under general anaesthetic, and there is no discomfort or pain.The catheter, which is a fine tube, is inserted through a special needle or small incision through the skin of the groin, and into a vein or artery. The Cardiologist then gently manipulates the catheter and guides it along with the blood flow into the various chambers of the heart, using low dose x ray screening to monitor its progress.
Once positioned, the catheter can be used to measure the pressures within each chamber and in the arteries and small blood samples taken to check the oxygen levels in the different parts of the heart. It is also possible to perform an angiogram where a special liquid is injected through the catheter, to show the details of the heart chambers and blood vessels, and these images are recorded on x-ray and video for the cardiac team to review at a later date, when they plan the best treatment for the condition.
If the catheterisation is being undertaken to treat a problem, this will all be done through the catheter using very fine surgical instruments to perform the surgery. This technique can be used to widen narrow valves or blood vessels (balloon dilation or stent), or it can be used to block off channels or some holes in the heart (for example ASD occlusion or Duct occlusion) and also to make holes in the septum if necessary (balloon septostomy).
The patient will not be allowed to eat or drink for about four hours before their Catheterisation, so if you have a young baby it may mean altering their feeding pattern to fit in with this. Sometimes older children are given a pre-med on the ward.
Children may also be given a patch with some "magic cream" on the back of each hand. This is called Emla Cream or Amitop, which reduces pain or discomfort when inserting a needle or cannula by numbing the skin.
Most units will let you go with your child to the catheter unit, and stay until the anaesthetist has put them to sleep if they are having a general anaesthetic. To do this he will use either a mask, or a needle inserted into your child's hand.
The time taken varies from about one to three hours depending on the type of defect and the procedure being undertaken, but you will usually be given an estimate of the time beforehand.
After the Test
Once the Cardiologist has completed the surgery or obtained all the information and blood samples required, they will remove the catheter and pressure is applied to the small hole in the groin until the bleeding stops. Your child will then be woken up and taken back to the ward. They may feel sleepy or restless for the next few hours, or perhaps even feel sick from the effects of the anaesthetic.
The nursing staff on the ward will carry out regular checks including taking their temperature and checking the wound in their groin. Sips of clear fluids will be allowed initially and if they are not sick, these will be increased. Milk and other drinks will be given later.
The cardiologist who performed the catheterisation will usually come and speak to you on the same day to tell you how it went. If the catheter was undertaken to obtain more information they may not have the full detailed results immediately and will want to take a closer look at the films and make calculations before explaining fully, which may be done either before discharge or at a later outpatient appointment.
Provided your child is well they will be allowed to go home the next day, but the groin area should be kept clean and dry whilst the wound is healing, and it is advisable for them not to go into water or have a bath for five days after catheterisation to prevent infection of the wound.
Although this is a complex procedure, in the vast majority of patients it can be performed safely without any problems. However, there are a few complications which occur occasionally:
- Blocked blood vessel
As a result of inserting the catheter tube into the blood vessels at the top of the leg, these can sometimes becomes blocked at the end of the procedure. This is usually just a temporary event, being unblocked by a heparin (blood thinning) medication or by use of a clot buster (such as streptokinase).
Sometimes there is bleeding from the groin after or during the procedure, and occasionally blood transfusion is required.
- Heart rhythm problems
These usually occur during the catheter procedure, and are treated at the time. They may require medicine or even a small electric shock during the operation.
Although it is often routine to use blood thinning medicine during a catheter procedure, clots may occur in the chambers of the heart. These are treated as for blocked blood vessels above.
As the operation will involve passing tubes into the heart, it is very important that the procedure is carried out very cleanly or in a sterile manner. Sometimes antibiotics are given, to treat or prevent infection.
- Unwell Children
Performing cardiac catheterisation on sick children is potentially dangerous and sometimes the children will need to go to intensive care after the procedure for recovery, and sometimes they will need to undergo emergency operation. Rarely, the outcome is fatal, but most children and young adults progress well and recover without any complications at all.