Effect of Abciximab on the Levels of Circulating Microparticles in Patients with Acute Myocardial Infarction Treated by Primary Angioplasty

BACKGROUND AND OBJECTIVES We investigated the effect of the additional use of abciximab during percutaneous coronary intervention (PCI) on the level of procoagulant microparticles (MPs) in patients with ST-segment elevation myocardial infarction (STEMI) who had undergone primary PCI. SUBJECTS AND METHODS In this study, we studied 86 patients with STEMI (72 men, age 58±13) who had undergone primary PCI. The decision to administer abciximab immediately prior to PCI was left to the discretion of the operator. Blood samples for analysis of MPs were obtained from the femoral artery before and after PCI. MPs with procoagulant potential were measured using a commercial kit. The cellular origins of MPs were determined by antigenic capture with specific antibodies. RESULTS Procoagulant MPs captured onto annexin V were not changed significantly after PCI {13.4±13.2 nM vs. 13.2±16.1 nM phosphatidylserine equivalent (PS eq), p=0.479}. Abciximab was used in 30 of 86 patients (35%) immediately prior to PCI. In patients who had undergone PCI without abciximab, no significant change in the level of MPs was observed after PCI. However, in the abciximab group, the level of circulating MPs was significantly decreased after PCI (12.0±10.7 nM vs. 7.8±11.7 nM PS eq, p=0.018). Levels of endothelial- and platelet-derived MPs also showed a significant reduction after PCI in the abciximab group. CONCLUSION Primary PCI with additional abciximab significantly reduced the level of procoagulant MPs regardless of their cellular origins in patients with STEMI.