Objective: To observe the effects of upstream versus downstream application of tirofiban on platelet aggregation and clinical outcomes (major adverse cardiovascular event, MACE) in patients with high-risk non-ST-segment elevation acute coronary syndromes (NSTE-ACS) undergoing percutaneous coronary intervention (PCI).
Methods: From July 2006 to July 2007, 160 high-risk NSTE-ACS patients undergoing PCI were randomized to receive upstream (4-6 h prior PCI) tirofiban and downstream (immediately prior to PCI) tirofiban. Platelet aggregation inhibition was determined at admission, before coronary angiography and after PCI. Incidences of MACE at 1, 3, 7, 30 and 180 days after PCI were compared. The incidences of bleeding complications and thrombocytopenia during tirofiban treatments were recorded.
Results: The extent of platelet aggregation inhibition post tirofiban was significantly greater in upstream tirofiban than that in downstream tirofiban group (8% vs. 42%, P<0.05). The incidences of MACE at various time points were similar between the two groups (all P>0.05). Aging, hypertension and type-2 diabetes were independent risk factors of MACE. The incidences of major and minor bleeding complications as well as mild thrombocytopenia during tirofiban treatments were similar between the two groups (2.5% vs. 1.3%, 1.3% vs. 1.3% and 1.3% vs. 1.3%, respectively; all P>0.05).
Conclusion: On top of aspirin and clopidogrel, upstream application of tirofiban is associated with increased platelet aggregation inhibition but the incidences of MACE up to 180 days post tirofiban are similar in the upstream and downstream tirofiban treated patients with high-risk NSTE-ACS after PCI. Aging, hypertension and type-2 diabetes were independent risk factors of MACE in these patients.