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We all know by now that the basic reason for heart attack is the development of sudden severe blockage in the blood vessels (called coronary arteries) of the heart muscle. This blockage prevents the free flow of blood and the oxygen it carries, to the heart muscle. The net result is death of the heart muscle cells, which we call heart attack.
Sometimes the blockages are incomplete, but severe enough to compromise blood supply to the heart during increased physical activity. A person may be completely comfortable when he is resting, but, when he or she engages in strenuous physical activity, chest pain may be precipitated. The characteristic feature of this pain is that the pain many times resolves with rest or by the use of nitroglycerine tablets (usually placed under the tongue). This kind of presentation is called exertional angina.
Although there are non-invasive tests (tests that do not involve getting inside the body), the ‘gold standard’ for testing the presence and evaluating the severity of any blockage in the coronary arteries, is the procedure called coronary angiogram. This is an invasive procedure that requires the use of needles and catheters, but gives definitive information in many cases and the same technique can be expanded to place stents or open blockages by inflating a small balloon using high pressure (coronary balloon angioplasty).
How is the procedure done?
After numbing the skin over the right or left groin with a local anaesthetic, a needle is used to puncture a blood vessel called ‘femoral artery’ that crosses that area. Using his access, catheters are threaded to reach the entrance to the heart. The coronary arteries take off from near the entrance to the left side of the heart. The catheters are positioned slightly inside the opening of the coronary artery, one at a time and a radiocontrast dye is injected. Pictures of the dye flowing through the arteries are obtained using X-rays. The restriction to the flow of dye caused by any blockages that may be present can be visualised and quantified using this technique.
What should you expect to feel?
The procedure may cause some anxiety, but patients are usually given medications to calm them down. There may be a warm sensation all over the body when the dye is injected. There may be slight discomfort in the area where the catheter is inserted. Occasionally, chest discomfort may be experienced.
Who should get this procedure done?
Need for the coronary angiogram will be determined by your cardiologist. The most useful and potentially life-saving use for coronary angiogram occurs in people who are in the process of having a heart attack. If such patients are brought to hospitals with cardiac catheterisation labs in a timely fashion, coronary angiogram and stent placement may not only save lives, but, will also reduce heart muscle damage significantly.
In general, people with blockage risk factors such as high blood pressure, high cholesterol, diabetes, obesity, etc., will require coronary angiogram, if their chest pain is determined to be suggestive of angina. In some patients like diabetics, shortness of breath may occur instead of chest pain. Such people may be candidates even in the absence of chest pain.
People who have had an abnormal stress test while being evaluated for their chest pain will generally need coronary angiogram, if determined to be the appropriate management by your cardiologist. There are other less common situations that may require coronary angiogram.
As a general rule, your cardiologist may perform a stress test, prior to proceeding with a coronary angiogram. A well-performed stress test will significantly increase the appropriateness of performing a coronary angiogram, in a given patient.
What happens after the test?
Once the test is completed, the catheters will be removed. Pressure will be applied to the area of catheter insertion, for about 15 minutes to stop bleeding. You will be asked to lie down, without moving, for several hours. Pain medications may be given, if your discomfort level is significant. You will be advised to not lift heavy weights for a few days. Your cardiologist will discuss the results of the test with you after the sedation wears away.
Coronary angiogram is a useful tool in the hands of experienced cardiologists, performing the procedure in well-equipped hospitals, on carefully selected patients.
Dr G Balachander
Cardiologist
Illinois, USA
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Effectiveness of coronary angiogram
