Comparative predictive and diagnostic value of flow-mediated vasodilation in the brachial artery and intima media thickness of the carotid artery for assessment of coronary artery disease severity.

BACKGROUND: While recent reports suggest that both flow-mediated vasodilation (FMD) in the brachial artery (BA), endothelium-dependent vasodilatation, and intima media thickness (IMT) in the carotid artery correlate with the extent of coronary artery disease (CAD), it is not clear which modality is a better predictor for CAD severity and whether either of these modalities are superior to conventional ST-segment depression in exercise stress electrocardiogram (ECG). Thus, the goal of the present study was to compare the predictive value of FMD and IMT for CAD severity and to evaluate the diagnostic accuracy.

STUDY: A total of 103 consecutive patients (62+/-9 years, 79 men) with clinically suspected CAD underwent FMD and nitroglycerin-induced dilation (NTG-D) in the BA as well as measurement of carotid artery IMT by using high-resolution ultrasound, and exercise treadmill testing. Coronary stenosis index (CSI) was calculated from coronary angiography.

RESULTS: Seventy-three patients had significant CAD, and 30 patients showed no CAD (NL). FMD was significantly lower and IMT was significantly higher in patients with CAD compared with NL patients (FMD, 3.7+/-3.0% vs. 7.5+/-2.9%; IMT, 1.1+/-0.2 mm vs. 0.7+/-0.1 mm). FMD and IMT correlated to CSI to a similar degree (r=-0.67, r=0.69, respectively), and there was a significant correlation between FMD and IMT. In contrast, NTG-D did not correlate with CSI or IMT. Further, the diagnostic accuracy of FMD and IMT was comparable or even better than that obtained with conventional ST-segment depression during exercise in this cohort.

CONCLUSIONS: FMD in BA and IMT could represent a surrogate diagnostic method for assessment of CAD severity.