Alternative Names coronary angiography, heart catheterisation, coronary angiogram, cardiac angiography
Definition Cardiac catheterisation is a test used to diagnose abnormalities of the coronary arteries. These are the vessels that supply blood to the heart. The test can also be used to examine the heart chambers and heart valves. Long thin tubes, called catheters, a TV system, and an x-ray machine are used to perform this examination. First, a catheter must be inserted through the skin and into a person's artery. An artery in the groin is the usual entry site. A contrast agent is then injected through the catheter. X-ray pictures are taken as the contrast travels through the person's arteries.
Who is a candidate for the test? This test may be advised for people who have or are suspected to have one of the following conditions:
stable angina or unstable angina. Angina refers to chest pain that occurs when too little oxygen reaches the heart for a short period of time.
coronary artery disease, or blockage in the arteries that supply blood to the heart. This is usually the cause of angina and heart attacks.
heart attack. This occurs when the heart is permanently damaged from being deprived of oxygen for an extended period of time.
How is the test performed? This test is performed in a special room containing cameras, TV screens, and x-ray devices called a catheter lab. The doctor who usually performs the test is a heart specialist, also called a cardiologist. Sometimes, an x-ray specialist, called a radiologist, may perform the test. During the procedure, the doctor and his or her assistants operate the equipment in the suite. A nurse checks the person's vital signs, such as the heart rate and blood pressure, during the examination.
To perform the test, the person lies on a flat platform. The doctor selects an artery in which to insert the catheter. The femoral artery in the right groin is usually used. The skin in the groin area is numbed with local anaesthetic. A small needle is then inserted through the skin and into the artery. Next, the doctor inserts a catheter into the artery through the small puncture made with the needle.
After being placed in the artery, the catheter can be advanced into the aorta. This is the largest artery in the body and connects directly to the heart. It can be used to access the heart chambers. The coronary arteries, which supply blood and oxygen to the heart also stem from the aorta. An x-ray machine is used to help guide the catheter into proper position.
The contrast agent is used to illuminate the structures of the heart and its arteries. The agent is injected into the catheter and enters the heart and heart arteries. This allows these structures to be clearly seen, as the contrast used is easily seen when x-ray pictures are taken. Several pictures are taken with an x-ray machine as the contrast agent travels through the heart and heart arteries. The doctor usually takes several pictures of the heart filled with contrast agent from different angles and positions. Usually, several injections of the contrast agent are needed. The images can be projected onto a TV or video screen so that the doctor can view the heart and its arteries during the test.
The standard test will typically take less than an hour. In more complex cases, the examination may last for several hours. The doctor may sometimes see an abnormality during the test that can be corrected during the examination. For example, a procedure called angioplasty is sometimes used to open up clogged arteries. This involves inserting a balloon catheter or other device through the catheter to open the area of blockage.
What is involved in preparation for the test? Special preparation is needed before the test. A brief physical examination is done to evaluate pulses in the groin and legs. If a person has a weak pulse in the groin, a different artery is used to insert the catheter. A review of the person's medical and surgical history is also needed. Questions may be asked about:
whether or not the person takes blood thinning medications such as aspirin or warfarin
whether the person has a bleeding tendency or any blood disorders
whether the person has any kidney disease or other kidney problems
Before the test, the person's blood is checked for indicators of a bleeding tendency and of kidney function. A woman of childbearing age will be screened for pregnancy. This is usually done with a urine or blood pregnancy test. Radiation from the test could harm an unborn child.
Six to eight hours before the test, the person cannot eat or drink anything. Dentures, eyeglasses and jewellery, such as necklace or earrings, should be removed before the examination.
The risks, benefits and complications of the test are usually explained to the person on the day of the procedure. Some possible complications from the test include:
If procedures are done during the examination, such as angioplasty, additional risks are involved. These will be discussed before the test by the doctor.
This test may be done on an outpatient basis. This means that the person can go home after the test. Sometimes, a patient must stay in the hospital for a day or more after the test. Often, this test is used for people in the hospital with serious or life-threatening heart conditions.
What do the test results mean? The doctor who performs the test is usually the one who reviews the results. This involves looking at the pictures taken during the examination to check for any abnormalities. The doctors will use the results of this test to help figure out the next course of action or a treatment plan.
Author: Lanita Dawson, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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