The purpose of this study is to determine whether shear-induced platelet aggregation is able to discriminate first acute coronary syndrome (ACS) from recurrent ACS

Predictive factors of recurrence of ACS are not well determined. Platelet aggregation and leucocyte activation seem to be involved in the pathogenesis. The aim of our study is to compare SIPA, platelet activation and platelet-leucocytes aggregates on the onset of the ACS and 3 months later in 2 groups of patients scheduled for a first episode of ACS or recurrent ACS .

Inclusion Criteria:

over 18 years old. informed consent signed. acute coronary syndrome not associated with co-morbidity as bleeding diathesis or myocardial infarction during the procedure.

clinical symptoms in agreement with myocardial infarction during the preceding 24 hours.

CK OR troponin elevation and one or more of the following criteria: ECG modifications transient ST elevation>1 mm. new inversion of ST <1 mm on 2 contiguous derivations.

Exclusion criteria:

Acute coronary syndrome with persistent ST elevation. Angioplasty in emergency before blood sampling. Inflammatory disease or cancer. Coagulation abnormalities. Antiphospholipid syndrome. Treatment by vitamin K antagonist. Severe disease with life expectancy lower than 2 years. One-year follow up impossible.

patients admitted in the intensive care unit with acute coronary syndrome