In conclusion, the OPTIENOX-PCI study will 1) obtain the Anti-Xa activity of enoxaparin at each time point of sampling; 2) assess the anticoagulation profile of high- versus standard-dose enoxaparin (0.75 mg/kg vs. 0.5 mg/kg), as well as that of staged- versus single-administration of high-dose enoxaparin (0.5+0.25 mg/kg vs. 0.75 mg/kg). The result of the present study will provide pharmacodynamical data for the design of future outcome studies.