Early effects on endothelial function of atorvastatin 40 mg twice daily and its withdrawal.

Combined hyperlipidemia is associated with endothelial dysfunction. Atorvastatin has lipid-lowering and pleiotropic properties, including a protective effect on endothelial function. This study investigated the short- and medium-term effects of therapy with atorvastatin and of its discontinuation on lipid lowering and endothelial function. In 33 patients with combined hyperlipidemia who had been randomized and treated for 6 weeks with 40 mg of atorvastatin twice daily (n = 23) or placebo (n = 10), fasting lipid levels and flow-mediated dilation (FMD) of the brachial artery were measured at baseline, after 12 hours, 1 week, and 6 weeks during therapy, and 36 hours after discontinuation of therapy. Thereafter, all patients received 20 mg/day of atorvastatin for another 6 weeks. In the atorvastatin group, low-density lipoprotein cholesterol was decreased by 30% and 46% after 1 and 6 weeks, respectively (p <0.0001 for the 2 comparisons). In patients who already showed an impaired FMD at the beginning of the study (n = 15), atorvastatin caused a significant improvement in FMD, from 2.6% at baseline to 4.0% and 6.3% after 1 and 6 weeks, respectively (p <0.05 and <0.001). Thirty-six hours after withdrawal of atorvastatin, the FMD in this group decreased again to 2.8% (p <0.05), whereas low-density lipoprotein cholesterol level remained unchanged. The 6 patients with normal FMD at baseline showed no improvement in FMD during therapy or any decrease after withdrawal of the drug. In conclusion, only patients with endothelial dysfunction profit from high-dose atorvastatin treatment. When the treatment is abruptly discontinued, the effect on FMD disappears in 36 hours.