A high maintenance dose of clopidogrel improves short-term clinical outcomes in patients with acute coronary syndrome undergoing drug-eluting stent implantation

Background Recurrent ischemic events occurred even during routine use of 75 mg clopidogrel in addition to aspirin, that indicated a potentially insufficient maintenance dosage of clopidogrel. The aim of the present study was to evaluate the short-term efficacy and safety of a 150 mg maintenance dose of clopidogrel following a 600 mg loading dose in patients with an acute coronary syndrome （ACS） undergoing drug eluting stent （DES） implantation. Methods Between November 2005 and November 2006, a total of 813 consecutive ACS patients undergoing DES implantation were enrolled. A 600 mg loading dose was administered before percutaneous coronary intervention （PCI） and patients were randomized to receive clopidogrel 75 mg or 150 mg for 30 days in addition to 300 mg aspirin daily. Primary end points were the composite of cardiac death, non-fatal myocardial infarction （MI） and urgent target vessel revascularization （UTVR）. Secondary end points included stent thrombosis （ST）, major and minor bleeding events at 30 days. Results At a follow-up period of 30 days, 4 （1.0%） patients in the 150 mg group and 9 （2.2%） patients in the 75 mg group （P 〉0.05） reached the primary end points. There was no significant difference in the incidences of MI （0.5% vs 1.2%, P〉0.05）, UTVR （0.7% vs 2.0%, P 〉0.05）, and cardiac death （0.2% vs 0.2%, P 〉0.05） between the two groups. The incidence of ST （0 vs 1.5%, P 〈0.05） was significantly lower in the 150 mg group than that in the 75 mg group. There were no significant differences between both groups regarding the risk of major （0.2% vs 0, P 〉0.05） or minor （0.5% vs 0.2%, P 〉0.05） bleedings. Conclusion A high clopidogrel maintenance dose of 150 mg daily following a 600 mg loading dose for the first month after PCI procedure reduces the risk of ST and appears to be safe in patients with ACS undergoing DES implantation.

A Randomized Controlled Trial of Adjunctive Bunchang Naoxintong Capsule (步长脑心通胶囊) Versus Maintenance Dose Clopidogrel in Patients with CYP2C19*2 Polymorphism

Objective：To determine the impact of adjunctive Buchang Naoxintong Capsule（步心脑心通胶囊,NXT） on dual antiplatelet therapy in patients with cytochrome P450 2C19＊2（CYP2C19＊2） polymorphism undergoing percutaneous coronary intervention（PCI）.Methods：Ninety patients with CYP2C19＊2 polymorphism were enrolled,and their genotypes were confirmed by polymerase chain reaction（PCR）.The patients were randomly assigned to receive either adjunctive NXT（triple group,45 cases） or dual antiplatelet therapy（dual group,45 cases） using a computer-generated randomization sequence and sealed envelopes.Platelet function was assessed at baseline and 7 days after treatment with conventional aggregometry.Subsequent major adverse cardiovascular events（MACE,including sudden cardiac arrest and acute coronary syndrome） were recorded during a 12-month followup.Results：Baseline platelet function measurements were similar in both groups.After 7 days,percent inhibitions of maximum platelet aggregation and late platelet aggregation were significantly greater in the triple versus dual group（42.3%±16.0%vs.20.8%±15.2%,P〈0.01,and 54.7%±18.3%vs.21.5%±29.2%,P〈0.01,respectively）.During the 12-month follow-up,the rate of subsequent MACE（6/45） was significantly lower in the triple group compared with the dual group（14/45;P〈0.05）.Conclusion：Adjunctive NXT to maintenance dose clopidogrel（75 g） could enhance the antiplatelet effect and decrease subsequent MACE in patients with the CYP2C19＇2polymorphism undergoing PCI.