Abstract 9660: The Impact of Anatomical Variation of the Brachial Artery for measuring Flow-mediated Vasodilation in Healthy Subjects and Patients with Cardiovascular Diseases

Abstract

Background: Measurement of flow-mediated vasodilation (FMD) is widely used for assessment of endothelial function. The purpose of this study was to evaluate the effect of anatomical variation of the brachial artery on FMD in healthy subjects and patients with cardiovascular diseases (CVD). Methods and results: There was no significant difference in the ratio of existence of a double brachial artery between healthy subjects (6.1%, 13/213) and patients with CVD (6.5%, 11/169). In healthy subjects, FMD was larger in a single brachial artery than in large and small vessels of a double brachial artery (7.2±3.4% vs. 4.7±3.3% and 4.5±2.5%, P<0.01, respectively), while FMD was similar in large and small vessels of a double brachial artery. In patients with CVD, there were no significant differences in FMD among a single brachial artery, large vessel of a double brachial artery and small vessel of a double brachial artery (3.3±1.4%, 3.1±2.3% and 3.6±2.1%). FMD in a single brachial artery was smaller in patients with CVD than in healthy subjects (P<0.01). There were no significant differences in FMD in the large vessel of a double brachial artery between the two groups or in the small vessel of a double brachial artery between the two groups. Nitroglycerine-induced vasodilation was similar in all arteries in healthy subjects and patients with CVD. These findings suggest that when measuring FMD, we should take care about the existence of a double brachial artery, especially a double brachial artery in healthy subjects. FMD measured in a double brachial artery may be underestimated in healthy subjects.