Factors associated with discordance between fractional flow reserve and resting full-cycle ratio

Resting full-cycle ratio (RFR), a non-hyperemic pressure ratio, is alternative to fractional flow reserve (FFR) for the evaluation of coronary artery stenoses. Although FFR and RFR results are often discordant using the cut-off values (0.80 and 0.89), factors associated with the discordance are unclear. The aim of this study was to explore factors related to the discordant results. We performed FFR and RFR measurements in a total of 408 vessels with intermediate coronary artery stenosis in 277 patients. Positive FFR and RFR were defined based on the cut-off values of 0.80 and 0.89. The discordance was determined as positive FFR and negative RFR (FFR ≤0.80 and RFR >0.89) or negative FFR and positive RFR (FFR >0.80 and RFR ≤0.89). Overall, FFR and RFR were significantly correlated (r = 0.76, p