Functional assessment 3.0: From wire through angio to OCT

Precision percutaneous coronary intervention (PCI) is a constantly evolving field, which is redefining the standards for indicated and optimised procedures. Physiological assessment of coronary stenoses is recommended by clinical practice guidelines as a tool to investigate the presence of ischaemia-generating lesions and to assist in making decisions on coronary revascularisation1 . Imagingguided PCI is associated with a more favourable prognosis than an angio-guided approach, especially in complex coronary settings (i.e., left main stem disease, chronic total occlusion, long lesions with severe calcifications)2 . The utilisation of either physiology or imaging post PCI to optimise the procedural result is associated with improved outcomes2,3. Against this background, a single tool able to provide both imaging and functional information is particularly appealing and may improve the penetration of both physiology and imaging. Indeed, despite strong evidence coming from randomised clinical trials and registries, physiology and intracoronary imaging are still underused, because the main barrier, more than economic and technical issues, is the persistence of confidence in the angio-guided approach by a significant number of operators4,5. In the present issue of EuroIntervention, Huang et al present a retrospective analysis to evaluate the diagnostic performance of an optical coherence tomography (OCT)-based functional assessment (optical flow ratio [OFR]