Asymmetric dimethylarginine determines the effect of simvastatin on endothelium-dependent vasodilation in severe hypercholesterolemia

Research into the influence of statins on the percentage of flow-mediated vasodilatation (%FMD) has revealed controversial results. Asymmetric dimethylarginine (ADMA) could provide a likely explanation for these controversial results. In this study, we attempt to establish whether ADMA levels influence the effect of 40 mg/day simvastatin on %FMD. A total of 120 hypercholesterolemic patients were enrolled. Patients were assigned to two groups, according to their ADMA level. Patients with ADMA greater than or equal to 1.7 µmol/l demonstrated decreased %FMD compared with patients with ADMA less than 1.7 µmol/l. There was no statistically significant reduction in ADMA level following 40 mg/day simvastatin therapy for 1 month between the two subgroups. In patients with ADMA less than 1.7 µmol/l, a significant increase in %FMD was observed. Statistically significant correlations were found between %FMD change and the baseline values of ApolB, ADMA and total homocysteine in the patients with ADMA level of less than 1.7 µmol/l (p < 0.001). Backward selection processes for predicting values of %FMD change selected ADMA as the most important significant factor related to %FMD change. ADMA level was found to determine the therapeutic effect of simvastatin on %FMD.