- The time course and differential effects of statin regimens on endothelial function after acute coronary syndromes (ACSs) are unknown and could contribute to the superiority of a more intense strategy. A subset of subjects who were enrolled in the PROVE IT-TIMI 22 trial (n = 50) underwent evaluation of vascular reactivity by high-resolution brachial ultrasound. Endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent sublingual nitroglycerin-mediated dilation (NMD) were measured at baseline and at 48 hours, 1 month, and 4 months after the initiation of 40 mg of pravastatin (n = 26) or 80 mg of atorvastatin (n = 24). After 4 months, low-density lipoprotein cholesterol was decreased by 32% in the atorvastatin group but was not different from baseline after ACS in the pravastatin group. C-reactive protein decreased similarly in the 2 groups. Brachial artery diameters at rest were similar in the 2 groups and at each time point of the trial. FMD and NMD increased significantly after 4 months by 27% and 24%, respectively (p <0.05), with no difference between groups. There was no correlation between the change in FMD and the change in lipids or C-reactive protein. In subjects who had received previous statin therapy (n = 15), there was no significant variation in FMD (p = 0.140) and NMD (p = 0.129). In conclusion, initiation of statin therapy soon after ACS is associated with improvements in endothelium-dependent and independent vascular reactivities after 4 months.