RESUMO
INTRODUCTION: The purpose of this study was to assess the change in theoretical probability of coronary artery disease (CAD) in patients with suspected CAD undergoing coronary CT angiography (CCTA) as first line test vs. patients who underwent CCTA after an exercise ECG. METHODS: Pre- and post-test probabilities of CAD were assessed in 158 patients with suspected CAD undergoing dual-source CCTA as the first-line test (Group A) and in 134 in whom CCTA was performed after an exercise ECG (Group B). Pre-test probabilities were calculated based on age, gender and type of chest pain. Post-test probabilities were calculated according to Bayes' theorem. RESULTS: There were no significant differences between the groups regarding pre-test probability (median 23.5% [13.3-37.8] in group A vs. 20.5% [13.4-34.5] in group B; p=0,479). In group A, the percentage of patients with intermediate likelihood of disease (10-90%) was 90% before testing and 15% after CCTA (p<0,001), while in group B, it was 95% before testing, 87% after exercise ECG (p=NS), and 17% after CCTA (p<0,001). CONCLUSION: Unlike exercise testing, CCTA is able to reclassify the risk in the majority of patients with an intermediate probability of obstructive CAD. The use of CCTA as a first-line diagnostic test for CAD may be beneficial in this setting.
