Should computed tomography coronary angiography be aborted when the calcium score exceeds a certain threshold in patients with chest pain?

ABSTRACT

BACKGROUND: There is ongoing debate about whether a computed tomography coronary angiography (CTCA) should be aborted when the calcium score (CS) exceeds a certain threshold in patients with chest pain. The aim of this study was to discover whether specific "cutpoints" regarding coronary artery CS could be determined to predict severe coronary stenoses assessed by CTCA, thus identifying patients amenable to an invasive diagnostic approach. METHODS: 294 consecutive patients with chest pain of uncertain cause who were referred for non-invasive diagnostic CTCA were included. Subjects underwent Agatston CS and CTCA using current 64-slice technology. RESULTS: Severe coronary stenoses were noted in 75 of 294 (25.1%) patients on CTCA. A very high prevalence of severe coronary stenoses was found in patients with CS ≥ 400 (87.0%). The CS had area under the ROC curve 0.86 to predict severe coronary stenoses on CTCA. The best discriminant cut-off point was CS ≥ 400 (sensitivity of 55.3%, specificity of 93.5, positive predictive value of 85.8%, negative predictive value of 84.0%). Multivariable logistic regression analysis controlling for traditional risk factors showed CS ≥ 400 remained an independent predictor of severe coronary stenoses on CTCA (OR 14.553, 95% confidence interval 4.043 to 52.384, p<0.001). CONCLUSIONS: CS can be used as a "gatekeeper" to CTCA in patients with chest pain. Due to the very high prevalence of severe coronary stenoses in patients with CS ≥ 400, further evaluation with CTCA is not warranted as these patients should be referred to invasive coronary angiography, avoiding the repeated exposure to ionizing radiation and iodinated contrast.