The STREAM Percutaneous Coronary Intervention Anticoagulant Sub-study

Inclusion Criteria:

1. Age equal or greater than 18 years

2. Onset of symptoms of STEMI < 3 hours prior to randomisation

3. 12-lead ECG (ST elevation will be measured from the J point) indicative of an acuteSTEMI: >2 mm ST elevation across 2 contiguous precordial leads (best 2 of V1-V6) orleads I, AVL for a minimum combined total of >4 mm ST elevation,or >3 mm ST elevationin 2 contiguous inferior leads (best 2 of II, III, AVF) for a minimum combined totalof > 6 mm ST elevation.

4. Informed consent received

Exclusion Criteria:

1. PCI (1st balloon inflation) expected to commence < 60 minutes from diagnosis (qualifying ECG) or inability to arrive at the cardiac catheterization laboratory (1stballoon inflation) within 3 hours after randomisation.

2. Anticipated or obvious problem with vascular access.

3. Previous CABG

4. Left bundle branch block or ventricular pacing.

5. Patients with cardiogenic shock - Killip Class 4

6. Patients with a body weight < 55 kg (known or estimated)

7. Uncontrolled hypertension, defined as blood pressure measurement > 180/110 mm Hg (systolic BP > 180 mm Hg and/or diastolic BP > 110 mm Hg) confirmed on repeat measures (2 documented measurements at any time) prior to randomization.

8. Known use oral anticoagulants (warfarin or coumadin) or GP IIb/IIIa antagonists withinthe preceding 7 days or recent administration of any IV or SC anticoagulation within 12 hours including: unfractionated heparin, enoxaparin, and/or bivalirudin.

9. Active bleeding, known bleeding diathesis/disorder including thrombocytopenia orclinical diagnosis associated with increased risk of bleeding including: known activepeptic ulceration and/or neoplasm with increased bleeding risk.

10. Major surgery, biopsy of a parenchymal organ, or significant trauma within the past 2months (this includes any trauma associated with the current AMI)

11. Any history of central nervous system abnormality (i.e. neoplasm, aneurysm,intracranial or spinal surgery) or recent trauma to the head or cranium (i.e <3months)

12. Any known history of haemorrhagic stroke or stroke of unknown origin

13. Ischaemic stroke or transient ischaemic attack (TIA) in the preceding 6 months

14. Prolonged or traumatic cardiopulmonary resuscitation (> 10 minutes) within the past 2weeks

15. Known acute pericarditis and/or subacute bacterial endocarditis

16. Known acute pancreatitis or known severe hepatic dysfunction, including hepaticfailure, cirrhosis, portal hypertension (oesophageal varices) and active hepatitis

17. Chronic dialysis or known renal insufficiency (prior S-creatinine >2.5 mg% (>220 µmol/l) for men and >2.0 mg% (>175 µmol/l)) for women

18. Pregnancy or lactation or parturition within the previous 30 days; women ofchildbearing potential must be using a medically accepted method of birth control

19. Previous enrolment in this study or treatment with an investigational drug or deviceunder another study protocol in the past 7 days

20. Known hypersensitivity to tenecteplase, alteplase, ASA, clopidogrel, enoxaparin, or toany of the excipients or to the contrast media used in angiography Inability to followthe protocol and comply with follow-up requirements or any other reason that theinvestigator feels would place the patient at increased risk if the investigationaltherapy is initiated