Per-Vessel Level Analysis of Fractional Flow Reserve and Instantaneous Wave-Free Ratio Discordance - Insights From the AJIP Registry.

Background: The per-vessel level impact of physiological pattern of disease on the discordance between fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) has not been clarified.

Methods and results: Using the AJIP registry, vessels with FFR/iFR discordance (133/671 [19.8%]) were analyzed. In the left anterior descending artery (LAD), physiologically diffuse disease, as assessed by pressure-wire pullback, was associated with FFR-/iFR+ (83.3% [40/48]), while physiologically focal disease was associated with FFR+/iFR- (57.4% [31/54]), significantly (P<0.0001). These differences were not significant in non-LAD (P=0.17).

Conclusions: The impact of physiological pattern of disease on FFR/iFR discordance is more pronounced in the LAD.