Dérimay F, et al. - Researchers sought to determine the clinical, angiographic and hemodynamic predictors of discordance between instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in this prospective multicenter CONTRAST study. This study included 587 patients, of which 466 patients (79.4%) had agreement between FFR and iFR (both negative, n = 244 [41.6%], or positive, n = 222 [37.8%]). Compared with FFR, iFR was negative discordant (FFR+/iFR-) in 69 (11.8%) patients and positive discordant (FFR-/iFR+) in 52 (8.9%) patients. Predictors of a negative discordant iFR were stenosis location (left main or proximal left anterior descending), more severe stenosis, younger age, and slower heart rate, while predictors of a positive discordant iFR were the absence of a beta-blocker, older age, and less severe stenosis.