Relationship Between Brachial Artery Flow-Mediated Dilation, Carotid Artery Intima-Media Thickness and Coronary Flow Reserve in Patients With Coronary Artery Disease

Association between atherogenic risk-modulating proteins and endothelium-dependent flow-mediated dilation in coronary artery disease patients

PURPOSE

Endothelial dysfunction is an early and integral event in the development of atherosclerosis and coronary artery disease (CAD). Reduced NO bioavailability, oxidative stress, vasoconstriction, inflammation and senescence are all implicated in endothelial dysfunction. However, there are limited data examining associations between these pathways and direct in vivo bioassay measures of endothelial function in CAD patients. This study aimed to examine the relationships between in vivo measures of vascular function and the expression of atherogenic risk-modulating proteins in endothelial cells (ECs) isolated from the radial artery of CAD patients.

METHODS

Fifty-six patients with established CAD underwent trans-radial catheterization. Prior to catheterization, radial artery vascular function was assessed using a) flow-mediated dilation (FMD), and b) exercise-induced dilation in response to handgrip (HE%). Freshly isolated ECs were obtained from the radial artery during catheterization and protein content of eNOS, NAD(P)H oxidase subunit NOX2, NFκB, ET-1 and the senescence markers p53, p21 and p16 were evaluated alongside nitrotyrosine abundance and eNOS Ser¹¹⁷⁷ phosphorylation.

RESULTS

FMD was positively associated with eNOS Ser¹¹⁷⁷ phosphorylation (r = 0.290, P = 0.037), and protein content of p21 (r = 0.307, P = 0.027) and p16 (r = 0.426, P = 0.002). No associations were found between FMD and markers of oxidative stress, vasoconstriction or inflammation. In contrast to FMD, HE% was not associated with any of the EC proteins.

CONCLUSION

These data revealed a difference in the regulation of endothelium-dependent vasodilation measured in vivo between patients with CAD compared to previously reported data in subjects without a clinical diagnosis, suggesting that eNOS Ser¹¹⁷⁷ phosphorylation may be the key to maintain vasodilation in CAD patients.

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.