Validation of a novel non-hyperaemic index of coronary artery stenosis severity: the Resting Full-cycle Ratio (VALIDATE RFR) study

Clinical Outcome of Lesions With Discordant Results Among Different Invasive Physiologic Indices ― Resting Distal Coronary to Aortic Pressure Ratio, Resting Full-Cycle Ratio, Diastolic Pressure Ratio, Instantaneous Wave-Free Ratio, and Fractional Flow Reserve ―

“…10,19, 21 RFR was calculated from each individual waveform using a fully automated off-line software algorithm (CoroLab; Coroventis Research AB, Uppsala, Sweden) following standardization of the pressure sampling rate to 100 Hz, as previously described. 22 RFR was defined as the point at which the ratio of Pd and Pa was lowest during the entire cardiac cycle 22 and averaged within 5 consecutive heart cycles. Among the total 1,024 pressure tracings, RFR calculation was not possible in 11 vessels because of insufficient quality of the resting pressure tracings.…”

Conversation in cardiology: Is there a need for clinical trials for the nonhyperemic pressure ratios?

“…As summarized in your editorial, the theoretical concepts of the five NHPRs (Pd/Pa, RFR, iFR, full diastolic pressure ratio, Pd/Pa during flat period of the dP / dt of aortic pressure [dPR], DFR) have been subjected to careful validation, as reflected in the recent publications. Several studies now support numerical and clinical equivalence between the NHPR . These validation studies have, in the main, reported numerical equivalence within the family of NHPR.…”

“…In addition, in the RESOLVE cooperative study that we performed in 1593 core lab assessed measures, there were some differences between Pd/Pa and iFR 5 (Figure 3 Several studies now support numerical and clinical equivalence between the NHPR. 6,[9][10][11][12][13] These validation studies have, in the main, reported numerical equivalence within the family of NHPR. Theoretical differences in NHPR around 0.01-0.02 are within test-retest variance and, at least to me, are not clinically meaningful.…”

Validation and comparison of non‐hyperemic pressure reserve to fractional flow reserve for assessment of coronary artery stenosis: A real world study

“…The resting full‐cycle ratio (RFR) is calculated based on unbiased identification of the lowest NHPR . RFR can highly correlate to iFR ( R 2 = 0.99, P < 0.001) and might even be more accurate than iFR in identifying the significant lesions . Multiple diastolic pressure ratios (dPR) have also been used and compared to iFR.…”