Is Sciencific evidence but in the eye of the beholder?

The DEFINE FLOW study was designed to find out whether invasive coronary physiology beyond fractional flow reserve (FFR) can refine lesion selection for revascularization or provide additional prognostic value [ [1] Stegehuis V.E. Wijntjens G.W.M. van de Hoef T.P. Casadonte L. Kirkeeide R.L. Siebes M. et al. Distal evaluation of functional performance with intravascular sensors to assess the narrowing effect-combined pressure and Doppler FLOW velocity measurements (DEFINE-FLOW) trial: rationale and trial design. Am. Heart J. 2020; 222: 139-146 Crossref PubMed Scopus (13) Google Scholar ]. Due to fundamental physiologic relationships, binary classifications of FFR and coronary flow reserve (CFR) disagree in approximately 30–40% of cases. Current guidelines recommend percutaneous coronary intervention (PCI) for lesions with an FFR value ≤0.80 [ [2] Neumann F.J. Sousa-Uva M. Ahlsson A. Alfonso F. Banning A.P. Benedetto U. et al. 2018 ESC/EACTS Guidelines on myocardial revascularization. Eur. Heart J. 2019; 40: 87-165 Crossref PubMed Scopus (3735) Google Scholar ]. In theory, the presence of a FFR-significant stenosis should also result in an abnormal (low) CFR value because the increase in flow following adenosine would be restricted due to the stenosis. Normal (high) FFR values should on the other hand be accompanied by normal (high) CFR values in the presence of a normal microvasculature. Impact of core laboratory assessment on treatment decisions and clinical outcomes using combined fractional flow reserve and coronary flow reserve measurements – DEFINE-FLOW core laboratory sub-studyInternational Journal of CardiologyVol. 377PreviewThe role of combined FFR/CFR measurements in decision-making on coronary revascularization remains unclear. DEFINE-FLOW prospectively assessed the relationship of FFR/CFR agreement with 2-year major adverse cardiac event (MACE) and target vessel failure (TVF) rates, and uniquely included core-laboratory analysis of all pressure and flow tracings. We aimed to document the impact of core-laboratory analysis on lesion classification, and the relationship between core-laboratory fractional flow reserve (FFR) and coronary flow reserve (CFR) values with clinical outcomes and angina burden during follow-up. Full-Text PDF