Editorial: Challenges in the contemporary assessment of coronary physiology

In the recently published Research Topic "Challenges in the Contemporary Assessment of Coronary Physiology" of Frontiers in Cardiovascular Medicine Journal, two review articles and three original studies were focused on the novel invasive and non-invasive imagebased modalities for the assessment of coronary physiology. The physiological assessment of coronary artery disease (CAD) has become an integral part of the decision-making process for myocardial revascularization. There are currently more than 10 modalities available for the functional assessment of coronary stenosis severity, although these physiological tools, whether intracoronary or image-based, are still not widely adopted (1). In this Research Topic, Dobric at al. have presented current status and future perspectives of commercially available image-based fractional flow reserve (FFR) which is derived from invasive coronary angiography (CA), such as: (1) quantitative flow ratio (QFR; Medis Medical Imaging System, Leiden, the Netherlands and Pulse Medical Imaging Technology, Shanghai, China); (2) vessel FFR (vFFR; Pie Medical Imaging, Maastricht, the Netherlands); (3) FFRangio (CathWorks, Kefar Sava, Israel); (4) computational pressure-flow dynamics derived FFR (caFFR; FlashPressure, Rainmed Ltd, Suzhou, China); and (5) AccuFFRAngio (ArteryFlow Technology, Hangzhou, China). These angiography-derived indices could provide an FFR estimation using 3D reconstruction of the interrogated coronary arteries derived from at least two separated angiographic projections taken during invasive CA, without the use of drugs that induce hyperemia, a significantly prolongation of procedural time, patient discomfort, additional costs and the possibility of damaging the coronary artery with the wire (1). All of these technologies showed excellent diagnostic accuracy for detecting the invasive FFR ischemic values 0.80 with areas under the curves (AUCs) between 93% and 98%, and with a low incidence of non-analyzable cases (0.9%-10%) (1-11). These findings implicate that angiography-derived physiological indices without hyperemia could provide fast, simple and accurate identification of coronary lesions associated with inducible ischemia. However, only QFR was prospectively validated in a large randomised controlled trial (FAVOR III China trial) which compare the clinical outcomes of myocardial revascularization guided by QFR and revascularization guided by standard visual angiographic assessment (12). This trial showed that myocardial revascularization guided