The value of endothelium dependent vasodilatation in diagnosing coronary artery disease and its comparison with the results of routine diagnostic tests

OBJECTIVE: To determine the predictive value of flow-mediated vasodilation (FMD) compared with angina pectoris, exercise electrocardiography, and myocardial perfusion imaging (MPI). METHODS: This study was carried out in Shahid Madani Heart Center, Tabriz, Iran from April 2004 to September 2006. A total of 92 patients with chest pain syndrome were enrolled in this study. Using high resolution ultrasound system endothelial function was evaluated, and the result of the flow-mediated dilation (FMD%) was defined as the percent change in the internal diameter of the brachial artery during reactive hyperemia related to baseline. RESULTS: Coronary artery disease (CAD) was documented in 77 (83.7%) patients. The percentage of FMD was lower in patients with CAD compared with those +/- 4.61, p=0.001). In comparison with typical anginal chest pain (sensitivity 46.7%, specificity 80%), exercise stress test (sensitivity 75%, specificity 60%), and MPI (sensitivity 96.5, specificity 55.6%) the receiver operator characteristic curve showed the percentage FMD optimal cut-off value as </=7.41 with a sensitivity of 87.0%, specificity of 66.7%, negative predictive value of 93.0%, and positive predictive value of 50%. CONCLUSION: In patients with chest pain syndrome, the FMD is a sensitive indicator of CAD with moderate specificity that is unable to predict accurately the extent and severity of it.