Long-term inhibition of platelet aggregation is essential for the
secondary prevention after
acute coronary syndromes (ACS). Inhibition of platelet aggregation with
acetylsalicylic acid (ASA) has been established as a safe and effective
therapy in this indication already end of the eighties in the preceding century. A decade later, with the introduction of the thieno-
pyridines, combined platelet aggregation inhibition became possible. This opened the door for new treatment strategies in interventional cardiology. The first substance,
ticlopidine was more or less replaced by the newer substance
clopidogrel, which has improved pharmacological properties and less side effects. Low dose ASA (75 mg/d) is still regarded as the standard
therapy for
secondary prevention after ACS. However, large clinical trials established
clopidogrel as at least as effective and safe as ASA in this indication. Following PCI with bare
metal stent implantation, a combined
therapy of ASA and
clopidogrel should be given for at least 4 weeks. After ACS with
non-ST-elevation myocardial infarction the combined
therapy with ASA and
clopidogrel gives a better outcome than ASA alone. Recently published clinical trials show superiority of this strategy in patients with
ST-elevation myocardial infarction, too. If a combined long-term platelet aggregation inhibition with ASA and
clopidogrel will be safe and more effective for
secondary prevention is discussed.