Hwang D, et al. - Researchers used other reference standards beyond fractional flow reserve (FFR) in order to assess the diagnostic performance of quantitative flow ratio (QFR). Overall 182 patients (253 vessels) with stable ischemic heart disease and 82 patients (105 nonculprit vessels) with acute myocardial infarction were analyzed. These patients had coronary stenoses evaluated with FFR, instantaneous wave-free ratio (iFR), and coronary flow reserve. By a core laboratory, contrast QFR analysis of interrogated vessels was carried out in a blinded manner. They assessed its diagnostic performance with respect to the other invasive physiological indices. Findings revealed a high correlation and agreement of QFR with respect to both FFR and iFR, although it was better when FFR was used as the comparator. For improving the adoption rate of physiology-based revascularization in clinical practice, a promising value of QFR was suggested, as a pressure-derived index not depending on wire or adenosine.