Background: The relationship between sex differences and long-term outcomes after fractional flow reserve (FFR)- and instantaneous wave-free ratio (iFR)-guided deferral of revascularization has yet to be elucidated.

Methods and Results: From the J-CONFIRM registry (long-term outcomes of Japanese patients with deferral of coronary intervention based on FFR in a multicenter registry), this study included 432 lesions from 385 patients (men, 323 lesions in 286 patients; women, 109 lesions in 99 patients) with paired data of FFR and iFR. The primary endpoint was the cumulative 5-year incidence of target vessel failure (TVF), including cardiac death, target vessel-related myocardial infarction, and clinically driven target vessel revascularization. The median FFR value was lower in men than in women (0.85 [0.81, 0.88] vs. 0.87 [0.83, 0.91], P=0.002), but the iFR value was comparable between men and women (0.94 [0.90, 0.98] vs. 0.93 [0.89, 0.98], P=0.26). The frequency of discordance between FFR and iFR was comparable between men and women (19.5% vs. 23.9%, P=0.34), although with different discordance patterns (P=0.036). The cumulative incidence of 5-year TVF did not differ between men and women after adjustment for baseline characteristics (13.9% vs. 6.9%, adjusted hazard ratio 1.82 [95% confidence interval: 0.44–7.56]; P=0.41).

Conclusions: Despite sex differences in the results for physiological indexes, the 5-year TVF in deferred lesions did not differ between men and women after adjustment for baseline characteristics.