| Objective: The aim of this study was to assess the beneficial efficacy and safety of the high maintenance dose of clopidogrel in acute anterior myocardial infarction(AMI)patients undergoing selective percutaneous coronary intervention (PCI).Methods: From April 2008 to December 2007, 52 patients ( 29 males and 23 females, average age was 64.44±8.57 years old ) who had been diagnosed as acute anterior myocardial infarction and prepared to selective percutaneous coronary intervention (PCI) treatment were enrolled into this study. The course of diseases were over 24 hours.Conforming to the AMI diagnostic criterion of ACC/AHA in 1999: persistent angina for more than 30 minutes and the cardiac enzyme peak twice than normal range and troponin positive and∕or ECG showing ST segment elevation 2 leads or new left bandle branch block. Determine the primary platelet aggregation rate (PAR) and the platelet aggregation rate with loading dose 300mg clopidogrel after 5 hours(PAR1).Calculate the absolute reduction(△PAR1) and define Inadequate response to clopidogrel as absolute reduction of platelet aggregation rate was <30%.All the patients with hypersensitiveness to clopidogrel,bleeding diathesis,thrombocytopenia, digestibility ulcer,mechanical complication, recent stroke and received GPIIb/IIIa receptor antagonist therapy were excluded. These 52 cases were randomly divided into two groups, the high maintenance dose group (n=26, 14 males, 12 females, 150mg clopidogrel per day) and the control group (n=67,15 males, 11 females 75mg clopidogrel per day). In each group,the detailed clinical information including: age, gender, risk factors, routine medicine. All patients received selective PCI. All patients received 300mg oral clopidogrel loading dose, aspirin,lipid-lowering, suppresstion of remodeling and Low Molecular Heparin injection in both groups. QCA (the stenosis more than 75 percent was positive) and TIMI Myocardial perfusion grading (TMPG) were used to analyse the lesion and reperfusion of the culprit vessel and myocardium. Record the information of patients in-hospital , in the 1 month and 6 months including the level of BNP, left ventricular ejection fraction (LVEF),the left ventricular peak ejection rate (LPER), the left ventricular peak filling rate (LPFR),the left ventricular time to peak ejection rate (LTPER) and left ventricular time to peak filling rate (LTPFR).SPSS 13.0 statistics software was used to analyse all data. The variables were presented as the means and the SD. Differences between two groups means were assessed with the t-test. TheΧ2 analysis or the Fisher exact test were used to test differences between proportions. Statistical significance was indicated by P value <0.05.Result:1.There were no significant differences in age, gender, risk factors between the high maintenance dose group and standard dose group.2.The CTFC of the high maintenance dose group after PCI was smaller than the standard dose group (24.20±1.05 vs 25.08±1.85, P>0.05). The percentage of TMPG 3 grade was higher in the high maintenance dose group (88.46% vs 73.08%, P >0.05).3.There was no significant difference in the level of BNP between the two groups after 1 month ( 139.65±105.61pg/ml vs 155.77±98.98 pg/ml,P >0.05),but there was significant difference after 6 months (34.81±19.71 pg/ml vs51.31±19.33 pg/ml,P <0.05).4.The primary platelet aggregation rate was no significant difference between the two groups(77.87±6.64%vs77.93±5.40%,P >0.05), but there was significant difference after 1 month and 6 months (16.21±6.27%vs26.95±5.97%,P >0.05;15.00±4.82%vs26.09±6.55%, P >0.05).5.The left ventricular peak ejection rate (LPER), the left peak filling rate (LPFR) 6 months after PCI in the high maintenance dose group was higher than the control group (2.89±0.20EDV/S vs 2.78±0.23 EDV/S, P <0.05; 2.71±0.22 vs 2.58±0.27, P <0.05), but there was no significant difference 1 month (2.70±0.26 EDV/S vs 2.72±0.25 EDV/S, P >0.05;2.55±0.28 EDV/S vs 2.53±0.27 EDV/S, P>0.05).The left ventricular time to peak ejection rate (LTPER), left ventricular time to peak filling rate (LTPFR) 1 month after PCI in the high maintenance were lower than the control group (144.27±16.65ms vs 152.54±13.30ms, P<0.05;152.00±15.97ms vs 162.31±15.14ms, P <0.05), but there was no significant difference 1 month (154.62±17.96ms vs155.92±14.11ms,P>0.05;165.00±19.20msvs168.96±16.57ms,P>0.05).6.There were less acute and subacute thrombosis cases in the high maintenance dose group than the standard dose group (0%vs.7.7%, P >0.05).There was no significant difference in hemorrhage events between two groups (11.54%vs3.85% ,p>0.05).Conclusion: The high maintenance dose clopidogrel (150mg per day) can improve cardiac function. There is potential benefit in increasing coronary blood flow and improving myocardium perfusion. High maintenance dose clopidogrel decreases the acute and subacute thrombosis but do not increase the hemorrhage events. |
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