BACKGROUND: The 2004 ACC/AHA guidelines on ST-elevation myocardial infarction state that it is reasonable to start treatment with abciximab as early as possible before primary percutaneous coronary intervention (PCI). We investigated the potential benefit of early use of abciximab by pooling data from all the available studies. METHODS: Six prospective studies were identified that had allocated 260 patients to receive early abciximab (either prehospital or soon after the patient arrived in hospital) and 342 to receive late abciximab (at the time of PCI). RESULTS: TIMI flow grade 2 or 3 was present in 42% of the early group compared with 29% in the late group (P = .001). After PCI, 59% of patients in the early group showed ST-resolution >or = 70%, compared with 41% in the late group (P = .003). The composite clinical outcomes death, new myocardial infarction, or repeat target vessel revascularization at 30 days occurred in 7.3% of the early group compared with 9.7% in the late group (odds ratio 0.73, 95% CI 0.41-1.32) and death alone occurred in 2.7% versus 4.7%, respectively (odds ratio 0.56, 95% CI 0.23-1.39). CONCLUSIONS: Early administration of abciximab improves epicardial patency (TIMI flow) before PCI and results in better myocardial tissue perfusion (ST-resolution) after the procedure. The promising effects on clinical outcomes need to be tested in larger studies.