Coronary Artery Calcium Aids Risk Classification in Elderly

Adding CAC to risk classification model most appropriate for those at intermediate risk

19 oct 2010-- Coronary artery calcium (CAC) levels can be used to fine-tune coronary heart disease (CHD) risk assessment in elderly people with no disease symptoms, according to a study in the Oct. 19 issue of the Journal of the American College of Cardiology.

Suzette E. Elias-Smale, M.D., of Erasmus Medical Center in Rotterdam, the Netherlands, and colleagues followed 2,028 elderly subjects without CHD symptoms for a median 9.2 years, during which 135 nonfatal myocardial infarctions and CHD deaths occurred. First the subjects were classified into low-, intermediate-, and high-risk categories in accordance with a Framingham risk model, and then the researchers added CAC levels (measured in Agatston units) to the risk model, assessed the impact of CAC on risk recalculation, and computed CAC cutoff values for risk reclassification.

Fifty-one percent of men and 53 percent of women initially classified as intermediate-risk were reclassified as a result of the inclusion of CAC levels. Among men, 30 percent of those initially at intermediate risk were moved to the low-risk category, and 21 percent were moved to the high-risk category. Among women, 29 percent of those initially at intermediate risk were moved to a lower-risk category and 24 percent were moved to a higher-risk category.

"In a general population of elderly patients at intermediate CHD risk, CAC scoring is a powerful method to reclassify persons into more appropriate risk categories. Empirically derived CAC cut-off values at which persons at intermediate risk reclassified to either high or low risk were 615 and 50 Agatston units, respectively," the authors write.

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