title: 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: OBJECTIVE
  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.
  
  
  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 ± 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 significantly greater area under the ROC curve (AUC) (0.892 vs 0.810, P < .001), whereas no significant 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Divisions of Cardiology and Radiology, Severance Cardiovascular Hospital, and Department of Research Affairs, Yonsei University College of Medicine, 250 Seongsanno Seodaemungu, Seoul 120-752, Republic of Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Kwon
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jaemin
authors.initials: J
authors.lastname: Shim
authors.forename: Ji Min
authors.initials: JM
authors.lastname: Sung
authors.forename: Mi Eun
authors.initials: ME
authors.lastname: Han
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Kang
authors.forename: Ji-Ye
authors.initials: JY
authors.lastname: Kim
authors.forename: Byoung Wook
authors.initials: BW
authors.lastname: Choi
authors.forename: Hyuk-Jae
authors.initials: HJ
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000401:mortality*; D015897:Comorbidity; D017023:Coronary Angiography / Q000706:statistics & numerical data*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000401:mortality*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*