Relationship between brachial flow-mediated dilation and carotid intima-media thickness in patients with coronary artery disease.

Background: Although flow-mediated vasodilation (FMD) of brachial artery and carotid intima-media thickness (IMT) are important surrogate markers in the process of atherosclerosis, information about relationship between both markers is insufficient. In the present study, we assessed extensively the relationship in patients with coronary artery disease (CAD).
Methods: The values of brachial FMD and carotid ultrasonography findings in 159 patients (67±8 years, 130 males) with angiographically verified CAD were retrospectively analyzed.
Results: In all patients, mean carotid IMT tended to be correlated with FMD, although the correlation was not statistically significant (R=-0.149, P=0.061). Maximum IMT was not correlated with the FMD (R=0.053, P=0.508). In addition, carotid artery diameter was significantly correlated with the FMD (R=0.290, P=0.0002). Prevalence of high IMT value (≥1.0 mm) was higher in the abnormal FMD group (4%>; N.=67), compared with the normal FMD group (≥7%; N.=24; P<0.05). Carotid artery diameter was larger in abnormal FMD group, compared with both groups of normal FMD (P<0.01) and borderline FMD (4-7%; N.=68) (P<0.01). In all patients, receiver operating characteristics analysis demonstrated that cut-off value of FMD to predict the prevalence of ischemic stroke was 3.7% (AUC=0.735, P<0.001). The cut-off value of maximum IMT was 1.9 mm, but was not significant (AUC=0.522, P=0.829).
Conclusions: Brachial FMD and carotid IMT would be different in clinical significance as a surrogate marker for pathophysiology of atherosclerotic disease.