The association between endothelial function, evaluated using flow-mediated dilatation (FMD), and the severity of coronary artery disease remains to be elucidated.A total of 245 consecutive patients with stable angina were prospectively enrolled. FMD was evaluated in the brachial artery before percutaneous coronary intervention. Patients were divided into 2 groups according to the FMD value (lower FMD group [FMD < 2.0], n = 82; higher FMD group [FMD ≥ 2.0], n = 163). The severity of coronary artery disease was evaluated using findings of angiography and optical coherence tomography, and compared between the 2 groups.The prevalence of left main (LM) disease was significantly higher in the lower FMD group than in the higher FMD group (8.5% versus 2.5%, P = 0.046), although the prevalence of multivessel disease was comparable between the groups. Lower FMD was independently associated with a higher prevalence of LM disease (odds ratio, 3.89; 95% confidence interval, 1.12-15.5; P = 0.033). A general linear model with multiple variables revealed that the minimal lumen area (MLA) in the culprit lesion was significantly smaller in patients with lower FMD than in those with higher FMD (regression coefficient b, -0.249 mm2; 95% confidence interval, -0.479--0.018 mm2; P = 0.035). The prevalence ofvulnerable plaque characteristics was comparable between the 2 groups.Patients with lower FMD had a higher incidence of LM disease and a smaller MLA in the culprit lesion. FMD may be a useful, noninvasive indicator for identifying patients with severe coronary artery disease.
Keywords: Endothelial dysfunction; Optical coherence tomography; Vulnerable plaque.