HIV-infected subjects on a stable protease inhibitor (PI) containing antiretroviral regimen with plasma HIV RNA \<500 copies/mL, who have LDL cholesterol levels \>130 mg/dL or fasting triglycerides levels \>200 mg/dL, will be randomized (1:1) to continue their current antiretroviral regimen or to switch the PI to atazanavir (ATV). Brachial artery reactivity will be measured before (at entry) and 12 and 24 weeks after subjects are randomized.
ARM A: Switch current PI to atazanavir 400 mg once daily plus current \> 2 nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) for 24 weeks.
Subjects currently on ritonavir (RTV) (400 mg BID or greater) or RTV-boosted PI (\<400 mg/day) , or tenofovir (TDF) as backbone NRTI therapy, will switch to ATV 300 mg boosted with RTV 100mg once daily.
ARM B: Continue current antiretroviral regimen (single or RTV-boosted PI plus \> 2 NRTIs) for 24 weeks
Brachial artery reactivity in response to two vasoactive stimuli (increased forearm blood flow and nitroglycerin) will be assessed by measuring brachial artery diameter.
