Effects Of Tirofiban On Recovery Of Coronary Flow And Infarct Size In Patients With Acute ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Objectives: ST-segment elevation acute myocardial infarction (STEMI) is the most devastating clinical syndrome, and make the cardiac metabolism, structure and function destoried. Primary percutaneous coronary intervention (Primary PCI) is one of the effective measures which can reduce the mortality of acute myocardial infarction at present. It can quickly opened infarct-related artery (IRA), improve reperfusion in the infracted region and prognosis in mortality of patients with STEMI undergoing primary PCI. It also could reduce myocardial infarction size. However, the rupture of inherent atheromatous plaques. the thrombus load, abnormal activation of platelet adhesion, and hypercoagulability associated with PCI are the causes of cardiovascular events. Multi-factor-mediated reperfusion injury is most important. Aspirin, clopidogrel can inhibit platelet aggregation, but to a certain limit. And platelet glycoproteinⅡb/Ⅲa (GPⅡb/Ⅲa) receptor antagonist blocked the ultimate necessary way of platelet aggregation. Tirofiban is currently the most widely used GPⅡb/Ⅲa receptor antagonist. So the tirofiban is alternative to solve the problem of repeated thrombosis like no-reflow and slow-reflow phenomena. Then the major adverse cardiovascular events and mortality can be reduced. We will split the STEMI patients into two groups in this prospectively experiment, use tirofiban hydrochloride both in vein and in coronary for tirofiban group, and the regular operational methods for non-tirofiban group during PCI. During the experiment, we will observe the IRA'TIMI Flow, Corrected TIMI Frame Count (CTFC), myocardial blush grade, myocardial infarction size, to evaluate the effect of tirofiban hydrochloride on recovery of coronary flow and myocardial infarction size in patients with acute myocardial infarction in PCI。Methods: A total of 142 STEMI patients (110males,32females),aged 60.23±12.57 years old were selected from the patients with primary PCI, from July, 2008 to November, 2010 in our hospital. A preoperative evaluation was made in all. A dose of 300mg aspirin and 300mg clopidogrel were given. They were randomly allocated to either primary PCI combined with tirofiban hydrochloride therapy in vein (2/3standard loading dose) and in coronary artery (1/3 standard loading dose) (tirifiban group, n=72) or primary PCI treatment alone after aspirin and clopidogrel by oral (non-tirofiban group, n=70). Heparin was administrated for 7-14 days in the two groups. Aspirin 100-300mg/d, clopidogrel 75mg/d and statins were given by oral, including ACEI or ARB, and/orβ-blocker, and/or nitrates. Primary PCI was performed in both groups. Baseline clinical characteristics, TIMI grade, CTFC, myocardial blush grade, duration of the disease, door to baloon time and myocardial infarction size were compared between tirifiban group and non-tirofiban group. Myocardial infarction size was calculated by IMAGEJ, and SPSS 17.0 was used in stastic analysis.Results: There were no significant difference between the two groups in baseline clinical characteristics before primary PCI (P>0.05), including the IRA, the number of stents, the time of on set, the door to balloon time. The IRA were opened successfully in both of the two groups. Although the percentage of TIMI grade 3 achieved in IRA after PCI in tirofiban group was higher than non-tirofiban group, there was no significant difference between the two groups (92.7% vs. 86.6%, P>0.05). The CFTC of IRA (29.36±12.50 vs. 37.48±11.94, P<0.05) in tirofiban group was lower than non-tirofiban group. While the percentage of myocardial blush grade 3 of IRA after PCI in tirofiban group was higher, but no significant difference was found in the two groups (72.5% vs. 64.3%, P>0.05). The myocardial infarction size is smaller in tirofiban group than non-tirofiban group,but there is no significant difference between the two groups (4389.90±1449.38 vs. 5582.39±1851.36, P>0.05). Conclusion: Application of tirofiban in patients with STEMI undergoing primary PCI can improve significantly reperfusion of infarct area, increase the blood flow of IRA. There was a trend that the myocardial infarction size was smaller in tirofiban group, however, no significant diference was found.