The tip of the catheter is pushed just inside a main coronary artery. Some dye is then injected down the catheter into the artery. Several x-ray films are rapidly taken as the dye is injected (the dye shows up clearly on x-ray films). The x-ray films are recorded as a moving picture and this is called an angiogram. The angiogram shows the vessels filling with blood and the sites of any narrowing can be seen.
The tip of the catheter is then put into the other main coronary artery and the test is repeated. So, an angiogram picture is built up of each of the coronary arteries and their branches.
You cannot feel the catheter inside the blood vessels. You may feel an occasional 'missed' or 'extra' heartbeat during the procedure. This is normal and of little concern. During the procedure your heartbeat is monitored by electrodes placed on your chest which provide a tracing on an ECG machine (electrocardiograph). Sometimes a sedative is given before the test if you are anxious.
When the test is over, the catheter is gently pulled out. If it was inserted through a small cut in the skin in the arm then you will normally need a few stitches. If it was inserted through a wide needle in your groin then a nurse will press over the site of insertion for about 10 minutes to prevent any bleeding.
How do I prepare for a coronary angiography?
You should get instructions from your local hospital about what you need to do. The sort of instructions may include:
- If you take warfarin (a 'blood thinning' drug), you will need to stop this for 2-3 days before the test. (This prevents excessive bleeding from the site of the catheter insertion.)
- If you take insulin or drugs for diabetes, the timing of when to take these on the day of the test may need to be clarified.
- If you may be pregnant, you need to tell the doctor who will do the test.
- You may be asked to stop eating and drinking for a few hours before the test.
- You may be asked to shave both groins before the test.
- You will have to sign a consent form at some point before the test to confirm that you understand the procedure, understand the possible complications (see below), and agree to the procedure being done.
How long does coronary angiography take?
It usually takes about 30 minutes. In most cases it is done as a day-case procedure.
After the test
- The doctor will discuss what he or she found during the test. A letter is also sent to your GP giving details of the test results.
- You will need to rest for a few hours after the test. You should ask a friend or relative to accompany you home. Most people are able to resume their normal activities the next day.
- There may be some bruising at the site of the catheter insertion which may be a little sore when the anaesthetic wears off. Painkillers such as paracetamol will help to ease this.
- You may need to have some stitches removed after about seven days if a small cut was made to insert the catheter.
Are there any risks or side-effects?
- One problem is that a bruise may form under the skin where the catheter was inserted (usually the groin). This is not serious, but it may be sore for a few days.
- The small wound where the catheter is inserted sometimes becomes infected. Tell your GP if the wound becomes red and tender. A short course of antibiotics will usually deal with this if it occurs.
- Some people get a short angina-type pain during angiography. This soon goes.
- The dye may give you a hot, flushing feeling when it is injected. Many people also describe a warm feeling in the groin when the dye is injected - as if they have "wet themselves". These feelings last just a few seconds (and the operator will tell you when they are about to inject the dye). Rarely, some people have an allergic reaction to the dye.
- Serious complications are rare, but do sometimes occur. The risk is mainly in people who already have serious heart disease. Your doctor will only recommend coronary angiography if they feel the benefits outweigh the small risk. Potential serious complications are:
- A heart attack occurring during the procedure. This occurs in less than 1 in 100 cases.
- The catheter may damage a coronary artery. This is rare, and occurs in less than 1 in 200 cases. If this occurs, the artery may be repaired by emergency heart surgery.
- A stroke is another rare complication.
- Rarely, some people (about 1 in 500) die during this procedure as a consequence of one of these serious complications.
©EMIS and PIP 2006 Updated: June 2006 PRODIGY Validated
