Fractional flow reserve and instantaneous wave-free ratio discordance in patients with severe aortic valve stenosis

Background It has been reported that discordance between fractional flow reserve (FFR) and Instantaneous Wave-Free Ratio (iFR) could occur in up to 20% of cases. However, there are no reports regarding discordance between FFR and iFR in patients with severe aortic valve stenosis (AS). Purpose We aimed to investigate the discordance between FFR and iFR in patients with severe AS. Methods Severe AS was defined as an aortic-valve area of ≤1.0 cm2, a mean aortic-valve gradient of 40mmHg or more, or a peak aortic-jet velocity of 4.0 m/s or more. Intermediate coronary artery stenosis was defined as 30% to 70% stenosis (visual estimation). FFR and iFR were calculated in 4 quadrants based on values of FFR ≤0.8 and iFR ≤0.89 (positive discordance; low FFR and high iFR, negative discordance; high FFR and low iFR). Results We examined consecutive 140 patients (164 intermediate coronary artery stenosis vessels). Mean FFR and iFR ± standard deviation was 0.82±0.09 and 0.82±0.14, respectively. The discordance was observed in 48 vessels (29.3%). In the discordant group, most of cases were negative discordance (45 cases, 93.6%). Binary logistic regression analysis showed that left anterior descending artery (Hazard Ratio 3.80; 1.55 to 9.31, p=0.0036) was independently associated with negative discordance. Conclusions In patients with severe AS, the discordance between FFR and iFR could be observed in 29.3% of the vessels, mostly negative discordance. The left anterior descending artery is an independent predictor for negative discordance. Funding Acknowledgement Type of funding source: None