Endothelial Dysfunction in Patients With Coronary Artery Disease: Insights From a Flow-Mediated Dilation Study

Background: The use of flow-mediated dilation (FMD) as a surrogate indicator for the extent of coronary artery disease (CAD) remains largely unknown. We assessed FMD at the brachial artery in 89 consecutive patients undergoing coronary angiography. Methods and Results: Patients were classified in groups 0 to 3 according to the number of diseased vessels and the SYNTAX score was calculated. The FMD decreased significantly from groups 0 to 3 (P < .001). There was a significant linear relation between SYNTAX score and FMD (corrected r(2) = .64, P < .001). In multivariate analysis, a reduced FMD was the only significant independent predictor of the presence of CAD (odds ratio [OR] 1.78, P = .032) and of CAD severity (OR 1.85, P = .005). Conclusion: This study confirms that FMD is reduced in patients with CAD and that such reduction in FMD is related to the extent of the disease. Therefore, FMD at the brachial artery is likely to represent a reliable indicator of CAD burden.