Short-term Effect of Upstream Administration in Comparison to Deferred Injection of Tirofiban on Patients with Acute ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Background: High bolus dose tirofiban has been demonstrated to provide greater inhibition of platelet aggregation, but the most appropriate timing of its administration remains unknown. Objectives: To evaluate the efficacy of upstream vs. deferred administration of tirofiban in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention (PCI) on clinical outcomes. Methods: The 660 patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention were divided into upstream (n=330, administration of tirofiban to all patients in emergency room) and deferred groups (n=330, treatment of patients with large thrombus burden or no-reflow phenomenon in cardiac catheterization laboratory during PCI). The primary end-points were death, nonfatal myocardial infarction (MI), stent thrombosis (ST), revascularization of targeted vessels (TVR) or major adverse cardiac events (MACE) at 1 month and 6 months following PCI, with safety end-point at 7 days. Results: Compared with that of the deferred group, there was a significant increase of left ventricular ejection fraction (LVEF) in the upstream group within 7 days (55.5 +/- 6.6% vs. 54.6 +/- 7.9%, P=0.011). The rates of 7-day and 1-month MACE in the upstream group were lower than those in the deferred group (1.5% vs. 4.2%, 3.3% vs. 7.0%, P=0.037 and 0.034, respectively). However, there were higher tendencies for major and minor bleedings in the upstream group (1.8% vs. 0.9%, 2.7% vs. 1.5%, P=0.315 and 0.280, respectively). Conclusion: To the Chinese patients with acute myocardial infarction undergoing primary PCI, upstream administration of tirofiban was slightly superior to deferred injection for short-term clinical outcomes.