Effect of Aspirin at the Acute Phase of Cerebral Ischemic Event. (Aspirin)

Laboratory Effect on Platelet Activity of the First 300 mg Oral Dose Aspirin at the Acute Phase of Cerebral Ischemic Event.

Aspirin is the only anti-platelet medication used at the acute phase of ischemic stroke. The investigators would like to study laboratory effect of the first oral 300 mg dose of aspirin, given at hospital, after an ischemic event. The principal hypothesis is that platelet activity would be able to recover during this day and could lead to ischemic recurrences. Two blood samples are accomplished. The first 2 hours after aspirin intake and the second 23 hours after. Photometric aggregometry are performed with arachidonic acid and collagen induced platelet aggregation, measure of thromboxan B2 levels and reticular platelets count.

Measure of platelet activity recovery within 24 hours after the first 300 mg oral dose of aspirin given at hospital at the acute phase of ischemic stroke

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.

Measure of effect of the first 300 mg oral dose of aspirin given at the acute phase of cerebral ischemic stroke for already aspirin treated

For patients already treated with a daily dose of aspirin, a supplementary withdrawn was done before aspirin intake.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.

Inclusion Criteria: Adult men and women Ischemic stroke less than 48 hours Signed consent Exclusion Criteria: Danger to prescription of aspirin (haemorrhagic risk...) Prescription of heparin or VKA