EDN1 and endothelial dysfunction: Sezgin et al. found that endothelial function was impaired in people with SCF, and the TIMI frame count was correlated with endothelial dysfunction.14 Pekdemir et al. showed that endothelin-1 (ET-1) was higher and NO concentration was lower in patients with SCF than in a matched group of control subjects, and it was suggested that this situation was due to endothelial dysfunction.22 The plasma levels of NO were also found to be lower in patients with SCF than in normal subjects.23,24