Coronary Artery Calcium Scoring Does Not Add Prognostic Value to Standard 64-Section CT Angiography Protocol in Low-Risk Patients Suspected of Having Coronary Artery Disease

Abstract

Purpose:To evaluate the prognostic outcome of cardiac computed tomography (CT) for prediction of major adverse cardiac events (MACEs) in low-risk patients suspected of having coronary artery disease (CAD) and to explore the differential prognostic values of coronary artery calcium (CAC) scoring and coronary CT angiography. Materials and Methods:Institutional review committee approval and informed consent were obtained. In 4338 patients who underwent 64-section CT for evaluation of suspected CAD, both CAC scoring and CT angiography were concurrently performed by using standard scanning protocols. Follow-up clinical outcome data regarding composite MACEs were procured. Multivariable Cox proportional hazards models were developed to predict MACEs. Risk-adjusted models incorporated traditional risk factors for CAC scoring and coronary CT angiography. Results:During the mean follow-up of 828 days 6 380, there were 105 MACEs, for an event rate of 3%. The presence of obstructive CAD at coronary CT angiography had independent prognostic value, which escalated according to the number of stenosed vessels ( P , .001). In the receiver operating characteristic curve (ROC) analysis, the superiority of coronary CT angiography to CAC scoring was demonstrated by a signifi cantly greater area under the ROC curve (AUC) (0.892 vs 0.810, P , .001), whereas no signifi cant incremental value for the addition of CAC scoring to coronary CT angiography was established (AUC = 0.892 for coronary CT angiography alone vs 0.902 with addition of CAC scoring, P = .198). Conclusion:Coronary CT angiography is better than CAC scoring in predicting MACEs in low-risk patients suspected of having CAD. Furthermore, the current standard multisection CT protocol (coronary CT angiography combined with CAC scoring) has no incremental prognostic value compared with coronary CT angiography alone. Therefore, in terms of determining prognosis, CAC scoring may no longer need to be incorporated in the cardiac CT protocol in this population.q RSNA, 20111 From the Divisions of Cardiology

Evaluation of postmortem MDCT and MDCT-angiography for the investigation of sudden cardiac death related to atherosclerotic coronary artery disease

“…However, in younger patients, a population which is mostly investigated in the forensic setting, noncalcified plaques have also been linked to episodes of acute chest pain. Kwon et al [30] showed that CT cannot assess the coronary stenosis of non-calcified plaques in low risk patients suspected of having coronary artery disease because coronary CT angiography coupled with coronary artery calcium has no incremental prognostic value when compared to coronary CT angiography alone. It has been demonstrated that the amount of calcified plaque may not be associated with an increased risk of future coronary events [31].…”

Coronary Artery Calcium Testing in Symptomatic Patients: An Issue of Diagnostic Efficiency

“…Data from the CONFIRM registry [34••] and others [54] have shown that CCTA provides superior prognostic information as compared to CAC testing among symptomatic patients (Fig. 2).…”

The Prognostic Significance of Coronary CT Angiography

“…Kwon et al [17] evaluated the differential prognostic ability of coronary CTA compared with CAC scoring and risk factors in 4,388 patients clinically referred for coronary CTA at a single center. These patients were of a mean age of 60 years old, 52% were men, 29% had low pretest probability of obstructive CAD, and the mean Agatston CAC score was relatively low (76 units).…”

“…As a result, calcium scoring in selected asymptomatic patients was recently endorsed by American and European guidelines, with the goal of refining risk prediction in selected patients to better guide the application of preventative treatments [38,39]. The robust prognostic information highlighted above in primarily symptomatic patients using coronary CTA, along with technical advances in CT technology that have markedly reduced radiation exposure [40] and data in symptomatic patients demonstrating that CTA provides prognostic information that is incremental to Agatston calcium scores [17,18], have prompted some investigators to evaluate coronary CTA as a screening test.…”