Prognostic value of coronary artery calcium score and coronary CT angiography in patients with intermediate risk of coronary artery disease

The aim of this study was to compare the prognostic value of coronary calcium scoring and coronary computed tomography (CT) angiography in assessing the cardiac risk and its temporal characteristics in patients at intermediate pre-test likelihood of coronary artery disease (CAD). Cardiac CT was performed in 326 patients at intermediate (15-85%) pre-test likelihood of CAD to evaluate calcium score and presence and severity of the disease. Patients were followed-up for the occurrence of major cardiac events (cardiac death, myocardial infarction, and unstable angina requiring revascularization). During follow-up (26 ± 12 months) 34 events occurred. Calcium score, extent of CAD, and plaque extent and distribution were higher (all P < 0.001) in patients with events than in those without. No patients with calcium score of 0 had events at follow-up. Calcium score (P < 0.001), number of segments with non-calcified or mixed plaque (P < 0.05), and segments-at-risk-score (P < 0.005) were independent predictors of events. Cardiac risk was greater for all time intervals and accelerated more over time with worsening of calcium score. In presence of coronary calcium, significant CAD further increased the probability of failure for all time intervals. Therefore, patients at intermediate CAD risk without coronary calcium do not need further evaluation with longer and higher-radiation-dose protocols, while in the presence of coronary calcium CT angiography is useful to further stratify patients.