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Coronary artery disease develops over time with the build-up of cholesterol and other fatty materials on the walls of coronary arteries. “When fatty material builds up, it attracts calcium. If enough calcium accumulates, the artery wall may become hard and even bone-like,” says Palmetto Health Heart Hospital cardiologist Dr. Stephen Humphrey.
Calcium scoring uses a highly sensitive and specially adapted CT scanner (cat scan) to measure the amount and distribution of the calcium inside the arteries, producing a calcium score. “There tends to be a correlation between the amount of calcium in an artery and the amount of fatty material in the artery wall,” says Dr. Humphrey. “Thus, the calcium score, in theory, can detect early coronary disease before it will be seen by other tests.”
Unfortunately, patients under age 55 may have significant coronary plaque, but not yet significant calcification to detect by this method. Other tests such as EKG, treadmill tests and nuclear scans measure blockages by detecting alterations in blood flow within the coronary arteries, providing more information about prognosis. Although a calcium-scoring test does not indicate blood flow problems nor provide a picture of the artery itself, it can detect the disease before there’s a blood-flow altering blockage.
Fortunately, the damaging effects of coronary artery disease can be controlled by adopting a heart-healthy lifestyle. A low-fat diet, regular exercise, smoking cessation, diabetes and blood pressure control, and the use of cholesterol lowering drugs will have the biggest effect.
“A calcium scoring test may help decide how aggressive we will be in the use of other diagnostic tests and treatments. It is critical to note that calcium scoring should never be used on its own to diagnose coronary artery disease” says Dr. Humphrey.
Calcium scoring should not be the only test used to diagnose coronary artery disease. “As we age, calcium naturally accumulates in the arteries regardless of the presence or absence of fatty plaque. So in patients over age 55, the calcium-scoring test becomes less reliable,” says Dr. Humphrey.
Also, the great majority of patients with diabetes will have a high calcium score, making this test less useful in the diabetic population. Calcium scoring is not, therefore, the best screening tool for coronary artery disease. Calcium scoring should ideally be used in special cases where the physician needs more information to factor into the decision of how aggressive an individual’s treatment program should be.