Effects of atorvastatin on ADP-, arachidonic acid-, collagen-, and epinephrine-induced platelet aggregation

Objective: Atorvastatin reduces the incidence of cardiovascular events. However, the effects of atorvastatin on platelet aggregation are unknown. Methods: Blood samples were obtained from 126 healthy volunteers. Prepared isolated platelet suspensions were adjusted with saline to three different concentrations of 100 x 10(9), 300 x 10(9), and 600 x 10(9) platelets/L. Platelet samples were incubated with atorvastatin (10(-7) mol/L, 10(-6) mol/L or 10(-5) mol/L), and stimulated with ADP (10 mmol/L), arachidonic acid (0.5 mmol/L), collagen (2 mu g/mL), and epinephrine (1 mg/mL). The maximal amplitude of aggregation and the curve slope were measured by electric impedance aggregometry. Results: Atorvastatin inhibited platelet aggregation at moderate (300 x 10(9)/L) and high (600 x 10(9)/L) concentrations. However, an inhibitory effect of atorvastatin at low concentrations (100 x 10(9)/L) was not observed. Conclusions: The study shows that atorvastatin inhibits platelet aggregation in vitro, and this inhibitory effect is related to platelet concentrations.