Role of electron-beam computed tomography and nuclear stress testing in cardiovascular risk assessment.

Although it is well recognized that stenotic coronary artery lesions carry a significant risk for cardiac events, the importance of nonstenotic lesions is generally underappreciated. However, many acute myocardial infarctions are caused by lesions that cause <50% stenosis. Coronary artery calcification is being increasingly studied as a marker of risk for cardiac events. Measurement of coronary artery calcium using electron-beam computed tomography is emerging as a useful tool to further risk-stratify patients who are otherwise at intermediate risk for events. Coronary calcium scores have been shown to add independent predictive value to traditional risk assessment.