To compare treatment with aspirin alone versus the combined antiplatelet treatment aspirin and clopidogrel after 12 months of combined antiplatelet treatment following drug-eluting stent (DES) implantation.

Drug-eluting stents (DES) substantially reduce restenosis compared with bare metal stents and represent a significant advance in percutaneous coronary interventions (PCIs). Accordingly, DES have been rapidly adopted into practice and are currently used in the majority of PCI procedures. Despite their rapid acceptance, DES are not without limitations. In particular, patients who receive DES (like those who receive conventional bare metal stents) remain at risk of a 1% to 2% incidence of stent thrombosis, which is often associated with devastating consequences like death or myocardial infarction. Understanding and eliminating mediators of stent thrombosis are thus important goals for optimizing the clinical benefits of DES. Delayed endothelial coverage after DES implantation has been demonstrated and is thought to prolong the window of vulnerability to stent thrombosis. Consequently, current recommendations for DES are: dual antiplatelet therapy for at least 12 months in patients at low risk of bleeding, especially with " off-label " use. Because of rare but severe very late stent thrombosis, the dual antiplatelet therapy is more and more prescribed in clinical practice for several years.But it has been clearly demonstrated that the combination of aspirin and clopidogrel (the thienopyridine the most used) significantly increase the rate of severe and moderate bleedings when compared to aspirin alone. This is important if we consider the possibility or the necessity to prolong the combined antiplatelet therapy after stent implantation.ProposalTo compare treatment with aspirin alone versus the combined antiplatelet treatment with aspirin and clopidogrel after 12 months of combined antiplatelet treatment after DES implantation

NB : On the decision of the sponsor, the latest patient monitoring was advanced to September 30, 2014 instead of January 2015.

Inclusion can be done either after stenting or 12 months later :

A: Patients admitted for DES implantation can be selected. After 12 months of bi therapy, they will be randomized

B: patients who have got a DES implantation 12 months before can be selected and randomised

Inclusion criteria:

• Patients on aspirin and clopidogrel therapy at 12 months after DES implantation
• Informed, written consent by the patient

Exclusion criteria:

• DES in left main coronary artery
• Oral anticoagulation therapy with coumadin derivatives
• Active bleeding; bleeding diathesis; history intracranial bleeding
• Known allergy or intolerance to the study medications: aspirin and clopidogrel
• Pregnancy (present, suspected or planned) or positive pregnancy test (In women with childbearing potential a negative pregnancy test is mandatory)
• Patient's inability to fully comply with the study protocol