Flow-mediated vasodilation and anatomical variation of the brachial artery (double brachial artery) in healthy subjects and patients with cardiovascular disease.

The purpose of this study was to evaluate the effect of anatomical variation of the brachial artery on flow-mediated vasodilation (FMD) in healthy subjects and patients with cardiovascular disease (CVD). There was no significant difference in the prevalence of double brachial artery between healthy subjects (6.1%) and patients with CVD (6.5%). 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). 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. There were no significant differences in FMD in the large vessel of a double brachial artery between the 2 groups or in the small vessel of a double brachial artery between the 2 groups. Nitroglycerine-induced vasodilation was similar in all arteries in healthy subjects and patients with CVD. When measuring FMD, the existence of a double brachial artery should be checked. FMD measured in a double brachial artery may be underestimated in healthy subjects.