• To compare the Kinetics of inhibition of platelet aggregation (aggregometry) and platelet activation (flow cytometry) with different loading doses of clopidogrel
• To evaluate the effect on various parameters of inflammation and necrosis and the safety of these loading doses

Inclusion Criteria:

1. Patient hospitalised with ischemic symptoms (onset < 48 hours) and at least one of the following characteristics of NSTEMI:

   • ECG ST or T changes
   • positive troponin

2. Patient treated on admission with 250-500 mg aspirin (oral or IV) and who will receive low dose aspirin (< or = 100 mg daily) from the next day on

3. Patient treated with bid LMWH (indicated dosage for this indication)

Exclusion Criteria:

1. Catheterization scheduled within 24 hours after randomisation

2. Patient presenting an absolute contra-indication to the use of clopidogrel and/or ASA:

   - history of drug allergy to thienopyridine derivatives or ASA

3. Severe uncontrolled hypertension (BP > 180 / 100 despite therapy)

4. Platelet count < 100 000 / mm3

5. Neutrophil count < 1800 / mm3

6. Patient with increased risk of bleeding, such as severe hepatic insufficiency, current peptic ulceration, proliferative diabetic retinopathy

7. History of severe systemic bleeding

8. Patient with any contraindication to LMWH

9. Patient treated with clopidogrel within the last 10 days

10. Patient treated with oral anticoagulants or hirudin or planned to receive these products during the hospitalisation period

11. Patient treated with ticlopidine, dipyridamol, NSAIDs (including Cox1 and Cox2 inhibitors), cilostazol, GPIIb IIIa antagonists or planned to receive any of these products within the next 24 hours following randomisation.

12. Patient whose arm venous status is incompatible with an indwelling catheter

13. Patient presenting an evolving cancer

14. Patient with NYHA class IV heart failure

15. Intubated and ventilated patient