Editor's page: Focus Issue Coronary Artery Disease

We present a series of articles focusing on current and new developments in the evaluation of coronary artery disease (CAD) using imaging techniques. In particular, this issue deals with some of the new aspects in diagnostic testing, risk assessment, and monitoring therapy in patients with chronic coronary syndromes. The imaging aspects of the ESC Clinical Practice Guidelines on Chronic Coronary Syndromes presented at the recent ESC Congress and the differences to the 2013 Guidelines on Stable Coronary Artery Disease are discussed.1 Also presented is the phenomenon that in many centres a decreasing pre-test probability of the tested population is seen, and is lower than currently assumed.2 Novel approaches to improved pre-test probability prediction are promising and may result in increased discriminatory power.3 Modern coronary computed tomography (CCT) offers a wealth of information beyond merely looking at luminal narrowing. There is mounting evidence that coronary atherosclerotic plaque volume and composition, as assessed by CCT, are strongly associated to clinical presentation.4 Coronary CTA radiomics may provide a new tool to more accurately identify vulnerable plaques compared with conventional methods5 and have the potential to greatly improve individual risk prediction. Hybrid PET-CT provides complimentary information on presence and localization of atherosclerotic lesions and myocardial perfusion abnormalities.6 Differences in the progression of coronary artery calcium score (CACS) between patients on statins and those without are suggested by the PARADIGM study: in the non-statin group CACS progression apparently indicated progression of both calcified and non-calcified plaque volume; under the effect of statins CACS progression indicated only progression of calcified plaque volume but no progression of non-calcified plaques.7 There have been concerns that in special populations CCT risk profiles may be different from the general population. The CONFIRM registry found that in older patients the presence of obstructive and non-obstructive CAD and segment involvement score remain important predictors of prognosis.8 The Western Denmark Cardiac Computed Tomography Registry found that in diabetes patients without CCT evidence of CAD the risk of myocardial infarction was low and similar to non-diabetics. With diabetes, however, patients with obstructive CAD had the highest risk of suffering a myocardial infarction.9 Quantitative flow ratio, a recently developed technique to calculate fractional flow reserve (FFR) based on 3D quantitative coronary angiography and computational fluid dynamics appears to be a feasible tool for selection of patients for invasive FFR referral.10 Oxygen sensitive magnetic resonance imaging now allows to study adenosine-induced transmural changes in myocardial oxygenation.11 This approach may offer a new and promising pathway for assessment of cardiovascular risk. A novel simplified manual long-axis strain assessment of cardiovascular magnetic resonance studies early after reperfused acute myocardial infarction provides incremental prognostic information beyond established risk stratification parameters.12 A very different approach, visualizing carotid plaque neovascularization using contrast-enhanced ultrasound may prove to be an intriguing and relatively simple, widely available and low-cost methodology to identify patients with complex and significant CAD.13 It is our hope that these reports can offer the readership of the EHJCI a perspective of some of the newer and promising capabilities of cardiovascular imaging. These approaches allow for better understanding of anatomy, physiology and function, and hold great promise towards improved risk stratification as well as for monitoring and guiding treatment in patients with chronic coronary syndromes. Conflict of interest: none declared. The opinions expressed in this article are not necessarily those of the Editors of EHJCI, the European Heart Rhythm Association or the European Society of Cardiology.