Diastolic Hyperemia-Free Ratio in Patients With Coronary Artery Disease: A Prospective Observational Study.

Background and objectives: Diastolic hyperemia-free ratio (DFR), an alternative to fractional flow reserve (FFR) for the assessment of intermediate coronary artery stenosis, helps reduce patients' time, and inconvenience. However, the validation data for DFR and FFR are lacking. We aimed to evaluate the diagnostic accuracy of DFR and FFR and to assess the effective decision making for revascularization using their values.

Methods: Patients subjected to an invasive physiological study for intermediate coronary artery stenosis at a single center in South Korea between August 2022 and January 2024 were prospectively recruited. We evaluated the correlation between DFR and FFR measurements and the diagnostic accuracy of DFR ≤0.89 to predict FFR ≤ 0.80. We also compared the correlation for each coronary artery.

Results: A total of 324 intermediate coronary stenotic lesions from 300 patients were evaluated using DFR and FFR values simultaneously. There was a strong linear relationship between DFR and FFR (r = 0.80; 95% confidence interval [CI], 0.76-0.84; p < 0.001). The diagnostic accuracy of the DFR was 92.0% in predicting FFR ≤0.80. When compared separately for each coronary artery, all vessels showed a strong linear relationship with no statistical differences between any of the vessels (p=0.641). There was also a strong linear relationship between DFR and distal coronary pressure/aorta pressure (r=0.93; 95% CI, 0.91-0.94; p<0.001).

Conclusions: There was a strong correlation between DFR and FFR and a high diagnostic accuracy rate of DFR compared to FFR. Good diagnostic performance of DFR was also observed in each coronary artery.

Trial registration: ClinicalTrials.gov Identifier: NCT05421169.