Intima-Media Thickness of Brachial Artery, Vascular Function, and Cardiovascular Risk Factors

Abstract

Cardiovascular diseases are associated with impaired flow-mediated vasodilation (FMD) and increase in carotid intima-media thickness (IMT). Both FMD and IMT are independent predictors for cardiovascular outcomes. When measuring FMD and nitroglycerine-induced vasodilation in the brachial artery, IMT can also be simultaneously assessed in the same brachial artery. The purpose of this study was to determine the relationships between IMT of the brachial artery, vascular function, and cardiovascular risk factors. We measured brachial IMT, FMD, and nitroglycerine-induced vasodilation by ultrasound in 388 subjects who underwent health examination (mean age, 45±22 years; age range, 19-86), including patients with cardiovascular diseases. Univariate regression analysis revealed that brachial IMT significantly correlated with age (r=0.71; P<0.001), body mass index (r=0.27; P<0.001), systolic blood pressure (r=0.40; P<0.001), diastolic blood pressure (r=0.31; P<0.001), heart rate (r=0.15; P=0.002), glucose level (r=0.18; P=0.01), and smoking pack-years (r=0.42; P<0.001), as well as Framingham risk score, a cumulative cardiovascular risk index for heart attack (r=0.49; P<0.001). FMD and nitroglycerine-induced vasodilation were inversely associated with brachial IMT (r=-0.39, P<0.001; r=-0.32, P<0.001, respectively). In addition, there was a significant relationship between brachial IMT and carotid IMT (r=0.58; P<0.001). Multivariate analysis revealed that age, sex, hypertension, and brachial artery diameter were independent predictors of brachial IMT. These findings suggest that brachial IMT may be a marker of the grade of atherosclerosis and may be used as a marker of vascular function, providing additive information for stratifying subjects with cardiovascular risk factors.