Influence of short-term simvastatin administration on parameters of autonomic nervous system activity and blood pressure in hypercholesterolemic patients with or without hypertension

Background The beneficial effects of statins are probably not exclusively related to lipid lowering activity. Therefore, we investigated the effect of simvastatin on blood pressure and heart rate variability (HRV), which can be used for studying autonomous nervous system activity. Material and methods In a prospective, placebo-controlled, crossover trial, we studied 9 males and 11 females aged 55.2 +/- 9.7 years with hypercholesterolemia (TC > 220 mg/dl), and normal blood pressure or essential hypertension stage 1-2. After 4 weeks of dietary modifications and placebo administration all subjects were given 20 mg of simvastatin for 4 weeks, followed by a placebo for another 4 weeks. Office and 24-h blood pressure (ABPM), the biochemical parameters of neuroendocrine function and HRV were evaluated. Time-domain and frequency-domain variables were studied such as: SDNN, r-MSSD, pNN50, TP, HF, LF and LF/HF ratio. Results All subjects had significant decrease in total and LDL-cholesterol as well as triglycerides. However, four weeks of simvastatin was not associated with a significant change in office or ambulatory blood pressure. Treatment did not affect basal or stimulated plasma levels of catecholamines, aldosterone, cortisol, neuropeptide Y, renin activity. The differences in HRV between groups did not reach statistical significance. No significant correlation between changes in serum lipid levels and change in cardiac autonomic indices was found. Conclusions This short, prospective, cross-over study has not shown significant effects of simvastatin on blood pressure, biochemical parameters of neuroendocrine function and heart rate variability (HRV) parameters in patients with hypercholesterolemia with or without hypertension.