Relationship between diastolic hyperemia-free ratio and fractional flow reserve in patients with aortic valve stenosis

Abstract Background Diastolic hyperemia-free Ratio (DFR) is new resting index and uses a pragmatic definition by including areas below the average aortic pressure with negative slope. Aortic valve stenosis (AS) exhibits left ventricular hypertrophy and impaired microcirculation. The relationship between DFR and fractional flow reserve (FFR) in the patients with AS has not been yet investigated. Purpose We aimed to compare DFR and FFR in each of AS group and Non-AS group and to elucidate a suitable DFR cut-off value predicting less than 0.80 of FFR. Methods We enrolled 761 consecutive patients (1033 vessels) who underwent both DFR and FFR in the intermediate coronary artery stenosis between July 2020 and December 2023 in our hospital. We compared the DFR values with FFR values between AS group and Non-AS group. AS was defined as an aortic valve area of 1.5 cm2 or less, a mean aortic valve gradient of 20 mm Hg or more, or a peak aortic-jet velocity of 3.0 m/s or more. Results AS group consisted of 55 patients and Non-AS group consisted of 706 patients. A good correlation between DFR and FFR was observed in AS group (R=0.713; p < 0.0001) and Non-AS group (R=0.758; p < 0.0001). The patient backgrounds were similar between AS and Non-AS groups (Table). Regarding physiological findings, DFR in AS group was significantly lower than in Non-AS group (0.83 ± 0.12 vs. 0.88 ± 0.11, p < 0.0001), but FFR was similar (0.80 ± 0.07 vs. 0.81 ± 0.10, p = 0.12). Receiver operating characteristic curve showed that a suitable cut off value of DFR for equivalent FFR value of 0.80 was 0.85 in AS group and 0.89 in Non-AS group, respectively (Figure). Conclusion In the patients with AS, DFR may overestimate intermediate coronary artery stenosis and the suitable cut off value was 0.85.2024 ESC AS DFR Table2024 ESC AS DFR Figure