Prognostic Impact of Lesion-Specific Hemodynamic Index and Disease Characteristics in Patients with Coronary Artery Disease Assessed by Diastolic Hyperemia-Free Ratio and Instantaneous Wave-Free Ratio (PRIME-DFRiFR).

BACKGROUND

The aim of this study was to investigate the consistency of diastolic hyperemia-free ratio (DFR) and instantaneous wave-free ratio (iFR) before and after lesions in the distal coronary artery.

METHODS

The PRIME-DFRiFR Study was a single-center, prospective, observational study that evaluated DFR and iFR at points distal and proximal to lesions in distal coronary vessels after angiography and successful percutaneous coronary intervention (PCI). Target lesions with diameter stenosis of 50% to 70% were selected, and DFR and iFR were evaluated from the vessel distal point, the lesion distal point, the lesion proximal point, and the vessel proximal point, respectively.

RESULTS

Thirty patients (23 males [76.7%]; age 70.6 ± 10.2 years) were enrolled between August 2022 and December 2023, with a total of 37 single intermediate coronary lesions, clinical manifestations of unstable angina, acute coronary syndrome, dilated cardiomyopathy, or syncope. The DFR and iFR values at the vessel distal point, lesion distal point, lesion proximal point, and vessel proximal point were 0.95 ± 0.06 and 0.94 ± 0.05, 0.96 ± 0.05 and 0.95 ± 0.05, 0.99 ± 0.03 and 0.99 ± 0.03, and 1.00 ± 0.01 and 1.00 ± 0.02, respectively. The Pearson correlation coefficients of the four point values were 0.894, 0.834, 0.667 and 0.632, respectively (p < 0.001).

CONCLUSIONS

The significant positive correlations indicate that DFR can show relevant pressure changes before and after lesions in a comparable manner to iFR. In this study, the biggest influencing factor for discordance between DFR and iFR was old myocardial infarction. Post-PCI results indicated that DFR wires appeared to maintain relatively good maneuverability with comparable accuracy to iFR wires.