Extending the Use of Coronary Calcium Scanning to Clinical Rather Than Just Screening Populations

Twenty-five years after its initial development, coronary artery calcium (CAC) scanning has become a relatively inexpensive test that has been extensively validated as a potent noninvasive means for assessing the burden of coronary atherosclerosis in asymptomatic individuals. A proportional relationship between the magnitude of CAC abnormality and the frequency of subsequent cardiac events over long-term follow-up has been consistently demonstrated, including observations from large patient and population-based cohorts.1–3 Incremental prognostic value over standard clinical assessments including the Framingham Risk Score and other scores of global risk has also been consistently reported.3,4 Consequently, the application of CAC scanning for assessing asymptomatic patients with intermediate clinical risk has now become part of clinical guidelines.5,6See Article by Engbers et al Information from CAC scanning may be used to favorably alter patient management in clinical practice. As an example, in the Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research (EISNER) trial, subjects were randomized to routine risk management with and without a concomitant CAC scan.7 In the scan group, incurred costs and intensity of treatment increased with high CAC scores, but decreased in the zero CAC subgroup. This counterbalance resulted in no net increase in downstream medical costs, which had been an initial concern with CAC scanning. Although there have been no subsequent large randomized clinical trials involving the effect of CAC scanning on patients management, its ability to aid in clinical management of selected asymptomatic patients is now endorsed in recent preventive guidelines.8Beyond its use for risk-stratifying asymptomatic individuals, there is now strong reason to consider applications of CAC scanning in symptomatic or asymptomatic patients being evaluated for obstructive coronary artery disease (CAD). Several of these potential uses of CAC scanning arise from its combination with the application of …