Abstract 2944: 64-Slice Computed Tomography Coronary Angiography in Patients with High, Intermediate or Low Pre-test Probability of Significant Coronary Artery Disease

Objectives We assessed the usefulness of 64-slice CT coronary angiography (CTCA) to detect or rule out coronary artery disease (CAD) in patients with various estimated pre-test probabilities of CAD. Background The pre-test probability of the presence of CAD may impact on the diagnostic performance of CTCA. Methods 64-slice CTCA (Siemens Sensation 64, Germany) was performed in 254 symptomatic patients. Patients with heart rates ≥65 bpm received beta-blockers before CTCA. The pre-test probability for significant CAD was estimated by type of chest discomfort, age, gender, traditional risk factors and defined as high (≥71%), intermediate (31–70%) and low (≤ 30%). Significant CAD was defined as the presence of at least one ≥ 50% coronary stenosis on quantitative coronary angiography which was the standard of reference. No coronary segments were excluded from analysis. Results The estimated pre-test probability of CAD in the high (N:105), intermediate (N:83) and low (N:66) group was 87%, 53% and 13%, respectively. The diagnostic performance of the CT scan was different in the three subgroups. The estimated post-test probability of the presence of significant CAD after a negative CT scan was 17%, 0%, and 0%, and after a positive CT scan 96%, 88% and 68%. Conclusions CTCA is useful in symptomatic patients with a low or intermediate estimated pre-test probability of having significant CAD, and a negative CT-scan reliably rules out the presence of significant CAD. CTCA does not provide additional relevant diagnostic information in symptomatic patients with a high estimated pre-test probability of CAD.