Coronary Artery Calcium Improves CHD Risk Assessment in Elderly
A coronary calcium score is a cardiovascular test that doctors may use to learn more about your risk for coronary heart disease. Although routine scans on people without symptoms of heart disease is not currently recommended by the American Heart Association, researchers have learned that coronary artery calcium (CAC) levels can be a powerful method to more appropriately classify risk status, particularly in elderly patients, thus getting earlier treatment.
Coronary Artery Calcium Score May Predict Latent Atherosclerosis
Suzette E. Elias-Smale MD of the Erasmus Medical Center in the Netherlands and colleagues followed over 2,000 elderly subjects without symptoms of coronary heart disease for approximately 9 years. The participants were initially classified into three risk categories (low, intermediate, and high) based on the Framingham risk model. After a CT scan was performed to assess coronary artery calcium levels, the patients were reclassified.
Just over half of the participants were initially determined to be at intermediate risk. Of those, following the CAC scoring, 21 percent of men and 24 percent of women were moved into the higher risk category.
A second study at the Tulane University School of Medicine observed over 10,000 patients with similar results. The amount of calcium accumulated in coronary arteries predicted whether an individual (with no symptoms of heart disease) had a fatal event within the next five years.
Another recent study learned that high CAC levels is associated with a 2.2-fold higher chance of regional wall motion abnormalities (RWMAs) – meaning that the motion of the heart muscle is abnormal, a risk factor of ischemic heart disease. “Participants with CAC scores of 100 or greater had more than double the chance of having an RWMA compared with participants with lower CAC scores," the authors of the study write.
Coronary artery calcium scoring can be used as a measure of subclinical atherosclerosis, as arterial plaques that cause blockages are usually a combination of fat, cholesterol, and calcium. Coronary artery calcium scoring is accomplished using an electron beam computerized tomography scan, or EBCT – sometimes called an ultra-fast CT. Calcium deposits show up as bright white spots on the scan.
Currently CAC scoring is only used for those at intermediate or borderline risk of having a cardiovascular incidence such as heart attack due to other factors such as age, sex, cholesterol levels, blood pressure and tobacco use. In these cases, the risk of heart attack in the next 10 years is between 10 and 20 percent, so the CAC scoring may help physicians better target prevention techniques.
Journal of the American College of Cardiology, October 19 issue
Radiology, September and October issues