Coronary calcium on electron beam tomography imaging as a surrogate marker of coronary artery disease.

Although currently recognized risk factors for coronary artery disease are helpful to predict the development of atherosclerosis, their ability to identify individual patients at risk of events is limited. Therefore, surrogate markers are being investigated to identify disease in its early phases in an attempt to decrease cardiovascular morbidity and mortality. Coronary artery calcification is a useful surrogate marker of coronary artery disease, and it can be visualized and measured noninvasively by means of electron beam tomography (EBT) imaging. Atherosclerosis starts to infiltrate the arterial intima layer much before luminal stenosis develops. Calcium is present in the large majority of mature atherosclerotic plaques, although, in rare cases, it may be absent. Recent research indicates that in selected patient subsets, coronary calcium may add incremental prognostic value to conventional risk factors for coronary artery disease and should therefore be used in association with such factors. EBT imaging for detection of arterial calcification is best employed in asymptomatic individuals at intermediate risk of coronary artery disease, symptomatic patients at low risk of coronary artery disease, and to track disease progression.