Cardiac Catheterisation

What is it for?

Cardiac catheterisation is a procedure using X-rays to get detailed pictures (angiograms) of the heart and the arteries feeding the heart muscle. It can also provide important information about the pressures within the heart and the function of the pumping chambers and the valves in the heart.

This test can help diagnose the cause of symptoms and/or establish the most appropriate treatment.

What does it involve?

Most catheterisations are performed as day case procedures. This means that most patients will be in hospital only for a day. Sometimes patients need to stay in overnight if, for example, the test is done late in the day.

The test will be done in a hospital which has a fully equipped cardiac unit. After being admitted you will be seen by your consultant. You will be asked to put on a hospital gown and will be taken to the X-ray room and asked to lie on a special table. Sticky pads (electrodes) will be applied to your body so that your heart rate can be monitored. Your blood pressure and the oxygen level in your blood will also be monitored. The skin at the top of your leg will be painted with antiseptic and you will be covered with sterile towels. (Sometimes the procedure is done through a small incision in the right arm or wrist in which case the arm is cleaned and the sterile towels applied accordingly).

The test is done under local anaesthetic. This means that an injection will be given into the skin. After a few minutes the skin will be numb but you may still be able to feel pressure as the operator feels for your pulse. You will be awake during the procedure and able to talk to the operator as procedure continues.

If the procedure is done from the leg, a needle will be inserted into the artery just below the skin. This will then be replaced by a soft plastic tube. You will not feel any sensation of this tube inside you. X-rays are then used to position the tube. Measurements of your blood pressure will be made. Pictures of your heart will then be taken by injecting some fluid (dye) into the arteries and into the main pumping chamber of the heart. This may give you the sensation for a few seconds of a "hot flush". Some people describe this as feeling as if they have wet themselves when in fact they have not. You will be aware of the X-ray machinery moving around to get pictures from different angles.

Patients do sometimes get angina (chest pain) when the pictures are taken of the arteries. If you get any discomfort you should tell the operator.

Are there any risks involved?

Your doctor will not have recommended cardiac catheterisation unless the likely benefits were thought to be greater than the risks involved. Cardiac catheterisation is relatively safe and serious complications are rare. It would be wrong to suggest, however, that investigations such as this can be performed on patients who may have serious heart problems without any risk. Less serious complications include bruising or bleeding at the point where the tubes are inserted. The risk of a serious event (heart attack, stroke or death) is approximately 1 in 1000.

Very occasionally there can be a sudden change in the rhythm of the heart during the procedure. If this happens you will be given appropriate drug treatment or, in certain special cases, an electrical shock to stabilise the heart rhythm.

If you are or believe yourself to be allergic to iodine or shellfish, please inform your consultant beforehand.

Please feel free to discuss with your consultant beforehand any worries you have about the procedure and especially if you feel unable to have the test done without a sedative.

Do I have to starve before the test?

Unless you are advised otherwise, please have a light breakfast (cereal or toast and tea or coffee) no later than 0630 on the morning of the test. You may drink clear fluids up to the time you arrive on the ward.

If your test has been scheduled for the afternoon, please do not eat after 1030 am.

I have diabetes, what should I do about my treatment for this?

If you have diabetes, please ask your consultant for specific instructions about what to do in preparation for the test and especially if you take metformin (glucophage).

Should I take all my usual medication on the day of the test?

Please take all your usual medication on the morning of the test. If you take warfarin or attend an anticoagulant clinic, please let your consultant know beforehand.

You may be asked to stop your warfarin or similar medication a few days before the test.

What happens after the test?

If the procedure is done from the leg the plastic tube will be removed. The operator or an assistant will then press for about 5 to 10 minutes on the point where the tube went in. Sometimes a special plug device will be inserted to seal the entry point. If the plug device (Angioseal®) is used in your case you will be given specific instructions about this. You will be rested on a bed or trolley after the tube has been removed. You will be asked to rest for a few hours or for a shorter time if the plugging device is used.

If the procedure is done from the arm the artery and the skin incision will be sewn up. Your arm will be bandaged. You will be rested, but sitting up and for a shorter period.

If the tubes are inserted at the wrist, a special cuff will be used to maintain pressure and prevent bleeding until the entry point is sealed.

The pulse in your foot, arm or hand will be checked regularly to ensure that all is well with the circulation.

Whichever way the procedure is done you will be given further instructions about what to do after returning home.

When will I get the results?

You should be given the results of your test before going home. A final decision about the most appropriate treatment for you may be delayed until the results of additional tests are known. If heart surgery is thought likely to be best for you a definite decision may be delayed until a heart surgeon has seen your pictures (angiograms).

Will I need to come to the outpatient clinic again?

This will depend on the results of your cardiac catheter test. You may be asked to return either to a cardiac clinic or to a clinic with another consultant. Alternatively you may simply be asked to report to your GP.

SPECIAL NOTE FOR FEMALE PATIENTS:

If you are still having monthly periods, please let your consultant know. This is because the test uses X-rays and can only be done safely in women during some days of the monthly cycle. The test will be done during the 10 days after the beginning of your monthly period. If you have not started your monthly period as expected on the day you are due for your catheter test, please tell your consultant.