Abstract: Objective To assess the effects of thrombus aspiration during percutaneous coronary intervention(PCI) on high risk non-ST element acute coronary syndrome(NSTEACS).Methods A total of 78 patients with NSTEACS were randomly assigned to the thrombus-aspiration group and the conventional PCI group.In the thrombus-aspimtion group,patients had thrombus-aspiration before urgent PCI;in the eonventional PCI group,patients underwent urgent PCI routinely.The endpoints included angiographic evidence of myocardial perfusion(myocardial blush grade),the peak volume of cardiac troponin T(cTnT) and left ventrieular ejection fraction(LVEF)one month later.Results In the thrombus-aspiration group and the conventional-PCI group,patients with blush grades 0/1 were 7.7 %(3/39) vs 28.2%(11/39),P < 0.05,grades 2 were 23.1%(9/39) vs 30.8%(12/39,P > 0.05) and grades 3 were 69.2 %(27/39) vs 41.0%(16/39),P < 0.05.The peak volume of cTnT [(4.7±1.3) μg/L vs(9.3±3.1) μg/L,P < 0.05 ] and LVEF one month later [(55±15) % vs(40±10) %(P <0.05) ] between the thrombus-aspiration group and the conventional PCI group were observed.Conclusion Thrombus aspiration during urgent PCI in patients with high risk NSTEACS shows an optimistic effect on myocardial perfusion,myocardial necrosis and heart function.