Abstract: Abstract Objective To investigate the ST-segment elevation myocardial infarction (STEMI) patients in primary PCI, thrombus aspiration and different ways of giving tirofiban acute and long-term effects. Methods Patients were divided into three groups:1) simple thrombus aspiration group. 2) thrombus aspiration + tirofiban given by peripheral venous group, after thrombus aspiration to be the first 10μg.kg tirofiban bolus, followed by maintenance dose 0.15μg.kg-1.min-1 for 24 hours. 3) thrombus aspiration + tirofiban given by intra-infarction related artery group,after thrombus aspiration to inject tirofiban 500μg through the suction catheter , followed by maintenance dose 0.15ug.kg-1.min-1 for 24 hours. To observe the case of recanalization,preoperative and 90minutes after angioplasty ST-segment of ECG,peak of CK-MB, left ventricular ejection fraction 24 hours and 6 months after angioplasty. Follow-up of patients with bleeding and cardiovascular adverse events. Results The basic situation of three groups of patients was not statistically significant, forward flow reached TIMI 3 level after thrombus aspiration.The case of ST-segment after 90 minutes: group 2) and group 3) were significantly different from group 1). And the difference between group 2) and group 3)was not obvious. Peak of CK-MB:group 2) and group 3) were significantly different from group 1). And the difference between group 2) and group 3) was significantly different too.24 hours after angioplasty the left ventricular ejection fraction of group 3) was higher than group 2) and group 1), there was statistically significant between group 2) and group 1) (p <0.05 ). The left ventricular ejection fraction of three groups showed no significant difference after 6 months . Three groups of patients during follow-up were not bleeding and cardiovascular adverse events. Conclusion Primary PCI in acute ST-segment elevation myocardial infarction , thrombus aspiration combined tirofiban is better than a simple thrombus aspirationin in protecting left ventricular function and improving myocardial perfusion in acute phase , Within the intra-infarction related artery is better than the surrounding intravenous administration. Thrombus aspiration and different ways of giving tirofiban had no difference in long-term impact of left ventricular function.

Key words: Myocardial infarction, Thrombus aspiration, Tirofiban, Myocardium perfusion, Left ventricular function