P06 Establishing a new cut off of calcium score

Introduction CT coronary angiography (CTCA) is the preferred test in patients with low to intermediate likelihood of coronary artery disease. This retrospective study was conducted to determine a new cut for calcium score without adversely affecting the diagnostic accuracy of CTCA. Methods CTCA was performed on a third generation dual-source CT scanner (Siemens Force 512 slice). Agatston method was used for the quantification of the coronary artery calcium. The degree of luminal narrowing was classified using the CAD-RAD scoring system. The coronary plaques were classified into calcified, non-calcified and mixed subtypes. We reviewed the results of any subsequent non-invasive (stress echocardiography, cardiac magnetic resonance perfusion imaging) and invasive (coronary angiography) tests to assess the correlation with CTCA. Results 296 patients were included in the analysis. 22% (64/296) did not go on to further investigations. 78% (232/296) underwent non-invasive or invasive tests. The correlation of CTCA with further investigations did not depend on total calcium score. 76% of CTCAs correlated with further investigations, 5% did not correlate and 19% had inconclusive results. (Multiple artefacts preventing complete CTCA interpretation). Conclusion The correlation or non-correlation of the CTCA results with further investigations was not affected by the total calcium score. Therefore we deem it is reasonable to proceed with a CTCA even when the calcium score exceeds 1000.