Platelet Reactivity in Stent Thrombosis Patients

Inclusion Criteria: * Patients with a history of a stent thrombosis in the period 2004-2008. Exclusion Criteria: * Persistent acute ST-segment elevation * Successful revascularization during the qualifying hospitalization, prior to study entry * Acute pulmonary edema, hypotension, or evidence of cardiogenic shock * Clinically significant liver disease * End stage kidney disease requiring dialysis * Use at study entry of drugs that are strong inhibitors of cytochrome P450 3A4 and CYP3A5 (i.e. clarithromycin, erythromycin, itraconazole, ketoconazole) * Contraindications to antithrombotic/antiplatelet therapy * Failed coronary intervention in the previous 2 weeks * Malignancies * Increased risk of bleeding (previous stroke in the past months, active bleeding or bleeding diathesis, recent trauma or major surgery in the last month, suspected aortic dissection, oral anticoagulation therapy with coumarin derivate within 7 days, recent use of GPIIb/IIIa inhibitors within 14 days, severe uncontrolled hypertension \>180 mmHg unresponsive to therapy) * Relevant hematologic deviations (haemoglobin \<100g/L (6,2 mmol/L) or hematocrit \<34%, platelet count \<100 x 109 /L or platelet count \> 600 x 109/L) * Known allergy to clopidogrel * Pregnancy (present or suspected) * uncontrolled hypertension at time of randomization