Influence of the coronary calcium score on the ability to rule out coronary artery stenoses by coronary CT angiography in patients with suspected coronary artery disease

Background: Recent guidelines for the workup of patients with chest pain and suspected coronary artery disease include coronary computed tomography angiography (CTA). However, its diagnostic value may be limited in patients with severe coronary calcification. Objective: We investigated the relationship between the extent of coronary calcium and the ability of coronary CTA to rule out significant stenoses in a series of consecutive patients with suspected coronary artery disease. Methods: 2614 consecutive patients with suspected coronary artery disease in whom coronary calcium scoring and coronary CTA had been performed by Dual Source CT were analyzed. The ability of coronary CTA to rule out coronary artery stenoses (fully evaluable coronary arteries and absence of any luminal stenosis >75%) was analyzed relative to the coronary calcium score. Results: The median coronary calcium score was 12, with calcium present in 60.5% of all patients. Coronary CTA ruled out stenoses in 82% of patients, while in 18% of patients at least one stenosis was found or could not be excluded. The threshold above which coronary CTA permitted to rule out stenoses in less than 50% of patients was an "Agatston Score" of 287. This threshold was significantly lower for male patients (213 vs. 330), for patients with a heart rate >65 beats/min (157 vs. 317) and for patients with a body mass index >= 25 kg/m(2) (208 vs. 392). The evaluability of coronary arteries decreased with increasing amounts of calcium and differed significantly between heart rates <= 65 beats/min and >65 beats/min (p < 0.0001). Conclusion: In the largest patient series evaluated so far, we identified an "Agatston Score" of 287 to represent a threshold above which coronary CTA permits to rule out coronary artery stenoses in less than 50% of cases. (C) 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.