LAUSR

A sixty-one-year-old man with a history of hyperlipidaemia, arterial hypertension, positive family history, smoking, and atypical angina pectoris was referred for investigation of coronary artery disease. (Panel A) Coronary computed tomography angiography (CCTA) revealed a non-stenotic atherosclerotic plaque located in the left main (LM) and the proximal left anterior descending artery (pLAD), exhibiting high-risk plaque features including napkin-ring sign, low attenuation, and positive external remodelling. Non-stenotic calcified lesions were also found in the mid-LAD and proximal right coronary artery. (Panel B) The patient underwent a N-NH3 positron emission tomography–myocardial perfusion imaging (PETMPI) test, which showed no perfusion abnormalities and normal myocardial flow reserve (MFR). (Panel C) Hybrid imaging allowing coregistration of CCTA and PETMPI demonstrated normal perfusion in the LAD territory. (Panel D) Computational simulation of local haemorheological parameters revealed (Panel Da) an area of normal endothelial shear stress (ESS) and normal velocity at LM, (Panel Db) an area of high ESS and high velocity at the most stenosed part of the high-risk lesion, and (Panel Dc) an area of low ESS and turbulent flow at the downstream plaque shoulders. Sustained low ESS increases local thrombogenicity and holds a proatherogenic role activating molecular cascades implicated in thin-cap fibroatheroma formation. The patient was prescribed high-dose statin and a short 2-year follow-up with non-invasive imaging was recommended. Such non-invasive triple hybrid imaging integrating coronary morphology, myocardial perfusion, and local haemorheology may provide a novel comprehensive multi-parametric assessment of coronary atherosclerotic risk, advance our pathophysiological understanding of atherothrombotic complications, and inform decision-making towards optimal patient management.