| Objective:Coronary heart disease(CHD) is the most common type of organ lesions due to atherosclerosis. It is also seriously harm to human health at present. Acute coronary syndrome(ACS) is a severe and acute clinical event in coronary heart disease. The major pathogenesis is unstable atherosclerotic plaque rupture or erosion which leads to suffering from coronary artery thrombosis. Besides, platelet activating is a key and initiating factor to thrombosis. Percutaneous coronary intervention therapy(PCI) is one of the main methods of treating the ACS, which itself can activate platelets and cause thrombosis. Therefore, effective antiplatelet therapy is the foundation for patients to undergoing percutaneous coronary intervention with stent implantation and acute coronary syndrome. Although great efforts were having made to assess the optimal duration of dual antiplatelet therapy(DAPT) after stent implantation, 2011AHA/ACC guidelines recommends at least 12 moths of aspirin and clopidogrel after DES implantation for patients at low risk of bleeding. There is surprisingly little evidence on the optimal mode of clopidogrel discontinuation once the decision to stop the drug has been made.The purpose of the present study is using monitor platelet function of patients with at least one-year DAPT after PCI by thrombelastography, and comparing with platelet activity between gradual discontinuation group and abrupt discontinuation group to explore whether gradual discontinuation is superior to abrupt discontinuation clopidogrel of chronic clopidogrel therapy in patients through planned clopidogrel withdrawal after PCI, which can provide guidance on the methods of clopidogrel discontinuation for patients under PCI.Methods:A total of 75 ACS patients who have received PCI during January 2013 to December 2013 and stadrad dual antiplatelet treatment(the combination of asprin and clopidogrel) at least one year, who were enrolled and divided to gradual and abrupt clopidogrel discontinuation.All the patients can finish follow-up in the Second Hospital of Hebei Medical University. These patients of gradual clopidogrel group(n=35) firstly received clopidogrel 75mg/d for 12 months, and then took 50mg/d for 2 weeks, and then took 25mg/d for 2 weeks; these patients of abrupt clopidogrel group(n=35) received clopidogrel 75mg/d for 12 months, and then stop using this kind of drug. We measured the platelet function by thrombelastography of all patients at the end of 12 months after dual antiplatelet treatment and 1 month after clopidogrel cessation. Baseline and residual platelet reactivity were described as MAthrombin and MAADP/AA, respectively. The rate of clopidogrel-induced platelet inhibition and the rate of aspirin-induced platelet inhibition were described as ADP% and AA%. Major adverse cardiovascular events(including cardiovascular death, myocardial infraction and recurrent angina) were record in 3 months after cloidogrel withdrawal.Statistical analysis was performed by SPSS 19.0. Measurement data were presented as mean ± standard deviation. The main statistical indicators were tested for normality and equality of variance test. Independent samples T test is used between two groups, and paired samples T test is used to inter-group. Enumeration data were presented as rate or percentage, Chi-square is used between two groups. Statistically significance was defined as P <0.05.Results: 1 There was no significant difference in sex, age, body mass index(BMI), hypertension, diabetes, hyperlipidemia, stroke, smoking, drinking, the type of drug-based treatment and blood test in patients between taper and abrupt clopidogrel cessation(P>0.05).2 No statistically significance difference was found in coronary angiography and the number and length of stent(P>0.05). 3 Comparion of palatelet reactivity between two groups 3.1 Palatelet reactivity of before clopidogerl discontinuation or decreaseThere was no significant difference for baseline,residual of on-treatment platelet reactivity, the rate of ADP-induced platelet inhibition and the rate of AA-induced platelet inhibition at the end of 12 months after dual antiplatelet treatment(P>0.05).MAthrombin(mm)62.91±4.89 vs. 62.42±4.76,P=0.672;MAADP(mm)41.98±14.80 vs. 42.59±13.03,P=0.850;MAAA(mm)21.46±5.23 vs. 22.51±4.98,P=0.393;ADP Inhibit(%) 48.05±6.37 vs. 45.99±6.79,P=0.195;AA Inhibit(%) 50.98±8.28 vs.52.97±10.03,P=0.369。 3.2 Palatelet reactivity of 1 month after clopidogerl discontinuation.There was no significant difference for baseline,residual of on-treatment platelet reactivity, the rate of ADP-induced platelet inhibition and the rate of AA-induced platelet inhibition after clopidogerl discontinuation 1 month(P>0.05).MAthrombin(mm)62.91±4.89 vs. 62.42±4.76,P=0.672;MAADP(mm)49.78±12.56 vs. 51.28±13.54,P=0.628;MAAA(mm) 25.82±4.95 vs. 26.78±5.01,P=0.423;ADP Inhibit(%) 6.56±2.24 vs. 5.91±2.45,P=0.251;AA Inhibit(%) 25.46±5.56 vs. 27.28±4.54,P=0.138 3.3 The changes of palatelet reactivity before and after clopidogerl discontinuation or decrease in each group.No statistically significance difference was found in baseline of palatelet reactivity each group(P>0.05). The residual of on-treatment platelet reactivity of before clopidogrel discontinuation or decrease was significantly less than after clopidogrel discontinuation, the difference was statistical significant(P<0.05). The ADP-induced inhibition rate and AA-induced inhibition rate of before clopidogrel discontinuation was significantly higher than after clopidogrel discontinuation, the difference was statistical significant(P<0.05).4 Adverse cardiovascular events within 3 months after clopidogrel cessationThere was no significant difference for adverse cardiovascular events between two groups within 3 months after clopidogrel cessation(tapered 0% vs. aburpted 5.7%, P=0.473).Conclusion:1 There is no significant difference on plataletet inhibit rate for gradual and abrupt discontinuation clopidogrel of chronic clopidogrel therapy in patients with planned clopidogrel withdrawal after PCI.2 There is a synergy for the combination using asprin and clopidogrel on palatelet inhibition. |
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