Contrasting Prognostic Value of Discordance Between Resting Distal-to-Aortic Coronary Pressure Ratio and Fractional Flow Reserve in Coronary Artery Disease.

BACKGROUND: Discordance between nonhyperemic pressure ratios and fractional flow reserve (FFR), observed in up to 20% of cases, complicates clinical decision-making for coronary revascularization and warrants further investigation of its clinical implications. This study aimed to evaluate the outcomes of medically managed discordant lesions between FFR and the resting whole-cycle distal-to-aortic coronary pressure ratio (Pd/Pa). METHODS: From the prospective IRIS-FFR registry (Interventional Cardiology Research In-Cooperation Society Fractional Flow Reserve), 9737 lesions in 7376 patients treated medically were analyzed. The lesions were grouped based on resting Pd/Pa (≤0.93) and FFR (≤0.80) values. The primary outcome was 5-year target-vessel failure, including target-vessel myocardial infarction and target-vessel revascularization, with death from any cause considered as a competing risk. The key secondary outcome was death from any cause. RESULTS: Discordance between resting Pd/Pa and FFR was present in 15.91% of lesions treated medically (n=1549). Lesions with resting Pd/Pa >0.93 and FFR ≤0.80 had a higher risk of target-vessel failure than those with resting Pd/Pa ≤0.93 and FFR >0.80 (adjusted hazard ratio, 1.67 [95% CI, 1.09-2.55]; P=0.020) but a lower risk of all-cause death (adjusted hazard ratio, 0.23 [95% CI, 0.11-0.52]; P<0.001). The reduction in target-vessel failure with revascularization was observed only in the group with resting Pd/Pa >0.93 and FFR ≤0.80. CONCLUSIONS: FFR predicts vessel-specific coronary events, whereas resting Pd/Pa is associated with overall survival. The contrasting prognostic value of discordant lesions underscores the clinical importance of a complementary assessment using both resting and hyperemic coronary physiological indices. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01366404.