ObjectivesThe aim of this study was to investigate the impact of myocardial area supplied by the coronary artery on fractional flow reserve (FFR).BackgroundVarious factors other than the degree of epicardial stenosis influence the physiological significance of a coronary artery stenosis.MethodsA total of 296 coronary lesions in 217 patients were analyzed by quantitative coronary angiography and FFR. Myocardial area supplied by the coronary artery distal to the stenosis was evaluated by angiography using a modified version of the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) score.ResultsPercent diameter stenosis of the coronary lesion was 57 ± 15% (mean ± standard deviation). FFR <0.80 was seen in 132 (45%) lesions. FFR was significantly correlated with minimum lumen diameter (r = 0.584, P <0.001), percent diameter stenosis (r = −0.565, P <0.001), lesion length (r = −0.306, P <0.001), and myocardial supply area (r = −0.504, P <0.001). Multivariate logistic analysis demonstrated that minimum lumen diameter (odds ratio [OR] = 0.031, 95% confidence interval [CI] = 0.013–0.076, P < 0.001), lesion length (OR = 1.038, 95% CI = 1.009–1.069, P = 0.001), and myocardial supply area (OR = 1.113, 95% CI = 1.079–1.147, P <0.001) were independent determinants for FFR <0.80.ConclusionsFFR, which is the index of physiological significance of coronary artery stenosis, is influenced by myocardial supply area distal to the stenosis as well as by its own minimal lumen diameter and lesion length. © 2013 Wiley Periodicals, Inc.