The purpose of this study is to evaluate the effect of a loading dose of two different statins on platelet reactivity (atorvastatin, metabolized by CYP3A4, and rosuvastatin, which is rather independent of this enzyme)in patients at least 5 days in therapy with aspirin and clopidogrel (with or without an undergoing treatment with statins) undergoing PCI for coronary disease with chronic stable angina and/or evidence of inducible myocardial ischemia.