Administration of 300 mg of aspirin, per os.

2 blood samples will be performed

We study laboratory parameters of the first 300 mg oral dose of aspirin given, within 48 hours, after ischemic cerebral event. For all patients, two blood sampling are performed, the first, during the third hour after aspirin intake and the second during the twenty-fourth hour. Platelet reactivity is studied on the basis of serum thromboxane B2 levels and light transmission aggregometry after stimulation of platelet-rich plasma by acid arachidonic and collagen 2µg/ml reported to results with collagen 20 µg/ml.

For patients already treated with a daily dose of aspirin, a supplementary withdrawn was done before aspirin intake. Platelet reactivity was studied on the basis of serum thromboxane B2 levels and light transmission aggregometry after stimulation of platelet-rich plasma by acid arachidonic and collagen 2µg/ml reported to results with collagen 20 µg/ml.