Endothelial dysfunction, assessed by measurement of brachial artery reactivity, is associated with coronary artery disease. Previous studies showed that patients taking HIV protease inhibitors (PIs) had a buildup of fatty deposits in their arteries and impaired flow-mediated vasodilation of the brachial artery, whereas endothelial function was normal in HIV-infected individuals not taking PIs. The effect of three different antiretroviral regimens on endothelial function in antiretroviral naïve HIV-infected patients will be examined in this substudy.
Patients in this substudy will have Brachial Artery Reactivity Tests (BARTs), which are painless ultrasound tests of an artery in the lower arm. Brachial artery reactivity will be measured at entry and at 4 and 24 weeks after patients are randomized to one of three open-label drug regimens in ACTG A5142. Brachial artery reactivity in response to two vasoactive stimuli (flow-mediated and nitroglycerin) will be assessed by measuring brachial artery diameter and flow velocity. Blood will be drawn at Weeks 4 and 24 for insulin and lipid tests. Patients will fast and refrain from tobacco and caffeine use for at least 8 hours prior to each study visit. For the duration of the substudy, patients will be asked not to change the amount of fruits, juices, antioxidants, and tea that they consume.