ExTRACT-TIMI 25 recruited 20,479 patients with STEMI for whom fibrinolysis was planned. Patients were randomized after treatment with aspirin and the fibrinolytic agent. All patients were randomized within 6 h of symptom onset. The choice of fibrinolytic agent was left to the treating physician.

UFH was given in a bolus of 60 U/kg, to a maximum of 4000 U, followed by an infusion of 12 U/kg/h, to a maximum of 1000 U/h, for at least 48 h.

Enoxaparin dosing varied according to patient age and renal function so as to reduce the risk of bleeding. Patients younger than 75 years received an IV bolus of 30 mg followed by 1.0 mg/kg every 12 h subcutaneously until hospital discharge. In patients aged 75 years and older, the bolus was omitted and the SC dose reduced to 0.75 mg/kg every 12 h until hospital discharge.

In patients of any age in whom creatinine clearance was less than 30 ml/min, the SC dose was reduced to 1 mg/kg every 24 h.

The primary efficacy end point was the composite of death or nonfatal recurrent myocardial infarction (reMI) at 30 days. The secondary efficacy end point was the composite of death, nonfatal reinfarction, or recurrent myocardial ischemia leading to urgent revascularization at 30 days. There were 3 secondary end points designed to measure net clinical benefit: