The purpose of this study is to determine whether a 6 month duration of clopidogrel therapy after DES implantation is not inferior to that of a 12 month therapy.

Drug elution from stent struts is associated with less smooth muscle cell proliferation and delayed stent strut re-endothelialization. Thus it seems conceivable that a longer duration of dual antiplatelet therapy (aspirin and clopidogrel) after DES implantation is needed. However, no studies have been done to investigate which is the optimal antiplatelet therapy duration after DES implantation. Therefore, the objective of the randomized, double-blind, placebo-controlled ISAR-SAFE study is to evaluate the safety and efficacy of a 6 month versus a 12 month duration of clopidogrel therapy after DES implantation.

Patients on clopidogrel therapy at least 6 months after DES implantation, who do not require a reintervention will be randomized to an additional 6 month period of clopidogrel or placebo. The patients will be followed-up for 9 months after randomization.

Inclusion Criteria:

• Patients on clopidogrel therapy at 6 months (-1/+2 months) after DES implantation
• Informed, written consent by the patient

Exclusion Criteria:

• Age ≤18 years
• Clinically symptoms, proof of ischemia and/or presence of angiographic lesions requiring revascularization
• Previous stent thrombosis
• DES in left main coronary artery
• ST-elevation and non-ST-elevation myocardial infarction during the last 6 months
• Malignancies or other comorbid conditions with a life expectancy of less than one year or that may result in protocol noncompliance
• Planned major surgery within the next 6 months with the need to discontinue antiplatelet therapy
• Active bleeding; bleeding diathesis; history intracranial bleeding
• Oral anticoagulation therapy with coumadin derivatives
• 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
• Prior enrollment in the same clinical trial.