OP1 Coronary artery disease and atherosclerotic plaque subtypes in patients with suspected angina and a coronary calcium score of zero

IntroductionThis post-hoc analysis of the SCOT-HEART (Scottish COmputed Tomography of the HEART Trial) assessed the frequency and implications of coronary artery disease (CAD) in patients with a zero coronary artery calcium score (CACS).MethodsAgatston CACS was assessed on non-contrast and CAD on contrast CT coronary angiography. Adverse plaque characteristics (APC) were visually identified as positive remodelling or low attenuation plaque and quantitative plaque burden was measured.ResultsOf 642 patients with zero CACS, CAD was present in 105 (16%). Compared to patients with normal coronary arteries, those with zero CACS and CAD were older (55±9 vs 53±10 years, p=0.016) and had higher cardiovascular risk scores (14±9 vs 12±8, p=0.013). On CTCA 92 (14%) had non-obstructive CAD, 13 (2%) obstructive CAD, 14 (2%) APC and 85 (13%) low attenuation plaque burden >4%. Compared to patients with normal coronary arteries, those with zero CACS and CAD were more likely to receive statins (67% vs 17%, p