This is a prospective, randomized, open-label, control-active trial performed in elective patients candidates to coronary drug eluting stent implantation who presented high-on-treatment platelet reactivity, immediately before coronary intervention (PCI). All patients are treated with aspirin (100 mg/day) and standard-dose clopidogrel (600 mg as loading dose and 75 mg daily as maintenance dose)for at least 7 days before PCI. Platelet function is assessed by the VerifyNow P2Y12 assay (Accumetrics, San Diego, CA). Patients are eligible to be enrolled if they have high-on-treatment reactivity defined as P2Y12 reaction units (PRU) >= 230, immediately before PCI. After PCI, patients are randomized to receive high-dose clopidogrel (150 mg daily) or high-dose atorvastatin (80mg/day) + high-dose clopidogrel (150 mg daily). Study visits and platelet function testing with the VerifyNow P2Y12 test are conducted at 7 and 30 days after randomization.