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What is a coronary angiogram?
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By Paul W. Johnson, MD, and Eric A. Cohen, MD
At present, the coronary angiogram is the most definitive test for diagnosing coronary artery disease. It allows clinicians to study the coronary arteries, which supply blood to the heart muscle, through a process that injects a contrast agent into the coronary arteries while X-ray imaging is performed.
Who needs it?
Outlining the coronary arteries can help clinicians determine if there’s any significant narrowings that may require further treatment, like angioplasty — balloon dilatation — or coronary bypass surgery. If a patient has chest pain or shortness of breath, for instance, and their symptoms can’t be adequately controlled by medication, clinicians perform an angiogram. It’s also performed on patients when a doctor believes they have high risk of suffering a myocardial infarction, otherwise known as a heart attack. Like all medical procedures, angiograms pose some health risk, which physicians should discuss in advance with each patient.
What to expect
A trained cardiologist performs an angiogram in a special procedure room that’s equipped to record X-rays and monitor the heart. To inject dye into the coronary arteries, a long hollow tube or catheter is passed along the body’s major blood vessel, the aorta. This catheter may be introduced through an artery at the groin or, occasionally, the arm. Clinicians clean the chosen site with antiseptic solutions and inject the patient with local anaesthetic. Once the area is numb, they insert a short tube or introducer sheath through the skin into the artery. Different catheters are then inserted through the sheath to perform angiograms on the left and right coronary arteries, as well as the left ventricle, which is the main pumping chamber of the heart.
To outline the coronary arteries from different angles, the X-ray equipment will move around the patient during the procedure. Most patients don’t feel any discomfort as the dye is injected into the coronary arteries, although they may experience a warm sensation flushing downwards from their head during imaging of the left ventricle. But it usually passes quickly. The whole procedure takes about 45 minutes.
After taking adequate images, clinicians remove the introducer sheath and prevent the puncture site from bleeding by either compressing it by hand or clamp for about 20 minutes. The patient is confined to bed for four to six hours immediately following the diagnostic test.
The aftermath
Prior to discharge a doctor will explain the results of the procedure and any further treatment that may be indicated. Patients will also be told when they can resume their regular activities and what to watch out for. Although most people are slightly anxious prior to their angiogram, they usually find it painless and often comment that it wasn’t as bad as they expected.
Dr. Paul Johnston is a clinical fellow in interventional cardiology at Sunnybrook & Women’s College Health Sciences Centre, where Dr. Eric Cohen is director of the cardiac catheterization laboratory. Dr. Cohen is also assistant professor at the University of Toronto’s Department of Medicine.
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