Antiplatelet effects of a 600 mg loading dose of clopidogrel are not attenuated in patients receiving atorvastatin or simvastatin for at least 4 weeks prior to coronary artery stenting.

AIMS: To test prospectively whether the antiplatelet effect of a 600 mg loading dose of clopidogrel is attenuated in patients receiving atorvastatin and simvastatin for at least 4 weeks prior to coronary artery stenting. METHODS AND RESULTS: Blood samples were obtained at least 2 h after receiving 100 mg aspirin and 600 mg clopidogrel and prior to coronary stenting from 90 patients without statin therapy and 90 patients with statin (atorvastatin and simvastatin) therapy for at least 4 weeks. Maximal and residual platelet aggregation was evaluated with optical aggregometry in response to ADP (5 and 20 micromol/l). Surface expression of IIb/IIIa (CD61) and P-selectin (CD62) was assessed with whole blood flow-cytometry at baseline and following stimulation (5 and 20 micromol/l ADP). Inhibition of ADP-induced platelet aggregation was not impaired in the presence of concomitant statin therapy. Moreover, patients with and without statin therapy did not differ in respect to all flow-cytometric parameters obtained. CONCLUSION: The antiplatelet effect of a high, 600 mg loading dose of clopidogrel is not diminished in patients receiving atorvastatin and simvastatin for at least 4 weeks prior to coronary stenting.     

急性冠状动脉综合征冠状动脉支架术后应用他汀类药物对氯吡格雷抗血小板作用无影响

目的探讨急性冠状动脉综合征（ACS）患者行冠状动脉支架术后服用阿托伐他汀或普伐他汀对氯吡格雷抗血小板作用的影响。方法研究对象为150例2006年4至12月成功实施冠状动脉支架术的住院ACS患者,术后第1天起随机接受阿托伐他汀20mg／d（n=50）、普伐他汀20mg／d（／7,=50）或无他汀（n=50）治疗。围术期抗血小板治疗为阿司匹林300mg／d,当天氯吡格雷负荷量300mg,继以维持量75mg／d。观测各组患者术后第1天（基线值）及第3天的血小板膜糖蛋白P-选择素（CD62P）、血小板活化复合物（PAC-1）表达及20μmol／L二磷酸腺苷（ADP）诱导的血小板最大聚集率（MPAR）。结果三组患者临床及CD62P、PAC-1和MPAR的基线值差异均无统计学意义。各观测指标第二次测定值与基线值的差值显示,阿托伐他汀、普伐他汀和无他汀组的ACD62P[（4．69±16．78）％、（1．35±10．86）％和（2．97±10．21）％]、APAC-1[（12．78±22．07）％、（8．01±21．23）％和（10．65±21．39）％l及AMPAR[（5．44±18．68）％、（7．15±19．59）％和（3．76±23．42）％]差异均无统计学意义（P〉0．05）。急性心肌梗死患者亚组分析结果表明,ACD62P[（7．50±19．35）％、（3．24±11．18）％和（2．53±8．87）％]、APAC-1[（13．40±24．62）％、（11．28±19．90）％和（10．11±21．29）％]及AMPAR[（7．56±19．11）％、（7．87±23．60）％和（6．75±23．30）％]三组间差异亦均无统计学意义（P〉0．05）。结论接受冠状动脉支架术的ACS患者服用阿托伐他汀或普伐他汀后,短期内未发现对氯吡格雷的抗血小板作用产生显著影响。     

阿托伐他汀或瑞舒伐他汀与氯吡格雷合用在非ST段抬高型急性冠状动脉综合征患者支架置入术后的近期疗效比较

目的比较阿托伐他汀或瑞舒伐他汀与氯吡格雷合用在非ST段抬高型急性冠状动脉综合征(NSTE-ACS)支架置入术后患者的近期疗效。方法共154例NSTE-ACS的患者接受支架置入术后,随机分为服用阿托伐他汀组(74例)及服用瑞舒伐他汀组(80例),术前服用阿司匹林(100mg)5 d、氯吡格雷(75 mg)5 d以上或术前12 h以上顿服氯吡格雷300 mg及阿司匹林片300 mg,于术前服抗血小板药前、手术当天、术后3、7 d及术后1、6个月抽取静脉血测定二磷酸腺苷(ADP)(浓度为10μmol/L)诱导的血小板聚集功能,观察住院期间及6个月的主要不良心脏事件(MACE)。结果两组患者的临床基线资料及服药情况差异无统计学意义,服用氯吡格雷(75 mg)5 d或顿服300 mg能达到明显的血小板聚集率抑制作用,血小板聚集率在阿托伐他汀组由基线的(57.2±10.3)%降至手术当日的(32.5±11.2)%,而瑞舒伐他汀组分别为(59.1±9.8)%和(30.4±10.1)%(均为P<0.01),而且这种抑制作用稳定持续至6个月之后。6个月时两组间总的MACE发生率差异无统计学意义(13.0%比15.0%,P>0.05),两组心原性死亡、非致死性心肌梗死、靶血管重建术、支架内血栓形成及出血事件差异均无统计学意义(均为P>0.05)。结论接受冠脉支架置入术的NSTE-ACS患者,服用阿托伐他汀或瑞舒伐他汀后,短期内未发现对氯吡格雷抗血小板作用产生显著影响,且两组间的近期疗效相近。     

瑞舒伐他汀和阿托伐他汀对氯吡格雷抗血小板活性的影响

目的观察瑞舒伐他汀和阿托伐他汀对氯吡格雷抗血小板活性的影响。方法选择60例冠心病患者接受阿司匹林100mg/d、氯吡格雷75 mg/d及低分子肝素5000 U/12 h治疗,5 d后随机分为阿托伐他汀20mg/d(阿托伐他汀组,30例)和瑞舒伐他汀10 mg/d(瑞舒伐他汀组,30例)。在服用氯吡格雷之前(基线值)、加用他汀类药物之前及服用他汀类药物3d后,用全血阻抗法分别测定不同浓度二磷酸腺苷(5、10、20μmol/L)诱导的血小板聚集率。结果与基线值比较,服用氯吡格雷5 d后和加服他汀类药物治疗3 d后,2组患者血小板聚集率明显降低,差异有统计学意义(P<0.05);与治疗前比较,阿托伐他汀组患者血小板聚集率有所升高,而瑞舒伐他汀组患者血小板聚集率有所下降,但差异无统计学意义(P>0.05)。结论经细胞色素3A4途径代谢的阿托伐他汀及不经细胞色素3A4代谢的瑞舒伐他汀,短期内对氯吡格雷抗血小板活性无影响。     

Accelerated platelet inhibition by switching from atorvastatin to a non-CYP3A4-metabolized statin in patients with high platelet reactivity (ACCEL-STATIN) study

Aims CYP3A4-metabolized statins can influence the pharmacodynamic effect of clopidogrel. We sought to assess the impact of switching to a non-CYP3A4-metabolized statin on platelet function among patients receiving clopidogrel and atorvastatin with high on-treatment platelet reactivity (HPR). Methods and results Percutaneous coronary intervention (PCI)-treated patients (n= 50) with HPR [20 μM adenosine diphosphate (ADP)-induced maximal platelet aggregation (MPA) >50%] were enrolled during chronic administration of atorvastatin (10 mg/day) and clopidogrel (75 mg/day) (≥6 months). They were randomly assigned to a 15-day therapy with either rosuvastatin 10 mg/day (n= 25) or pravastatin 20 mg/day (n= 25). Platelet function was assessed before and after switching by conventional aggregometry and the VerifyNow P2Y12 assay. Genotyping was performed for CYP2C19*2/*3, CYP3A5*3, and ABCB1 C3435T alleles. The primary endpoint was the absolute change in 20 μM ADP-induced MPA. After switching, MPAs after stimuli with 20 and 5 μM ADP were decreased by 6.6% (95% confidence interval: 3.2-10.1%; P < 0.001), and 6.3% (95% confidence interval: 2.5-10.2%; P = 0.002), respectively. Fifty-two P2Y12 reaction units fell (95% confidence interval: 35-70; P < 0.001) and the prevalence of HPR decreased (24%; P < 0.001). Pharmacodynamic effects were similar after rosuvastatin and pravastatin therapy. In addition to smoking status, the combination of calcium channel blocker usage and ABCB1 C3435T genotype significantly affected the change of 20 μM ADP-induced MPA. Conclusions Among PCI-treated patients with HPR during co-administration of clopidogrel and atorvastatin, switching to a non-CYP3A4-metabolized statin can significantly decrease platelet reactivity and the prevalence of HPR. This switching effect appears similar irrespective of the type of non-CYP3A4-metabolized statin.     

择期冠状动脉介入治疗患者氯吡格雷抵抗现象的观察

目的:利用流式细胞术观察择期冠状动脉介入治疗患者所服用药物氯吡格雷的作用特点及氯吡格雷抵抗现象。方法:选取60例择期冠状动脉介入治疗患者,在服用氯吡格雷前、术前(服药后5天)、术后2小时及术后5天分别采血,利用流式细胞术测定其二磷酸腺苷诱导的血小板聚集率及血小板表面活化的糖蛋白Ⅱb/Ⅲa复合物(PAC-1)的表达情况。结果:60例患者在服用氯吡格雷前及术后5天的血小板聚集率和PAC-1的表达基本符合正态分布曲线。氯吡格雷抵抗的发生率在术前为25%,术后2h为30%,术后5天为13%。不同基础血小板聚集率组中,术后2h氯吡格雷抵抗发生率无明显差别(P>0.05)。结论:在择期冠状动脉介入治疗患者中,氯吡格雷的抗血小板作用存在个体差异,部分患者存在氯吡格雷抵抗现象。氯吡格雷抵抗可能不受基础血小板聚集率高低的影响。     

Platelet aggregation according to body mass index in patients undergoing coronary stenting: should clopidogrel loading-dose be weight adjusted?

BACKGROUND: A 300 mg clopidogrel loading-dose (LD) is widely used as an adjunct antithrombotic treatment to reduce the risk of thrombotic events early after coronary stenting (CS). Antithrombotic drugs commonly used during percutaneous coronary interventions, such as heparin and platelet glycoprotein IIb/IIIa inhibitors, but not clopidogrel LD, are weight-adjusted, and few data are available on which is the most effective clopidogrel LD regimen. The aim of this study was to assess whether body mass index (BMI) influenced platelet response to clopidogrel LD in patients undergoing CS. METHODS: Adenosine diphosphate (ADP)-induced platelet aggregation (PA) was assessed by light transmittance aggregometry in 48 patients on aspirin treatment undergoing CS receiving a 300 mg clopidogrel LD at intervention time. PA was assessed at baseline and up to 24 hours after intervention. Patients were divided into 2 groups according to BMI: overweight (BMI greater than or equal to 25 kg/m2; 29 patients) and normal weight (BMI<25 kg/m2; 19 patients). PA was significantly higher in overweight than in normal weight patients at baseline (60.1+/-18.6%; versus 47.6+/-13.5%; p=0.01), at 24 hours (42.3+/-18.4% versus 38.5+/-18.3%; p=0.02) and during the overall study time (p=0.025). Percentage of inhibition of PA 24 hours following clopidogrel LD was suboptimal (<40%) in 59% and 26% of overweight and normal weight patients, respectively (p=0.04). An elevated BMI was the only independent predictor of suboptimal platelet response. CONCLUSION: These data suggest that overweight patients may need a higher loading-dose of clopidogrel and/or an adjunct antithrombotic treatment to adequately inhibit platelet aggregation early after CS.     

PAR-1 genotype influences platelet aggregation and procoagulant responses in patients with coronary artery disease prior to and during clopidogrel therapy

Genetic variations of the protease-activated receptor-1 (PAR-1) have been associated with platelet receptor density and linked to thrombin receptor-activating peptide (TRAP)-induced phenotypes of platelet aggregation and P-selectin expression. We investigated whether the PAR-1 intervening sequence-14 A?>?T dimorphism influences platelet procoagulant activity. We also determined whether the P2Y₁₂ antagonist clopidogrel could offset any observed functional polymorphism of the PAR-1 receptor by inhibiting P2Y₁₂-mediated amplification of TRAP-induced responses. We studied 54 patients listed for elective percutaneous coronary intervention assessing TRAP-induced platelet aggregation and markers of procoagulant activity. Platelet responses were measured at baseline, 4?h post clopidogrel 300?mg, and 10 and 28 days following clopidogrel 75?mg daily. Each patient was genotyped for the PAR-1 intervening sequence-14 A/T dimorphism. Increased platelet aggregation and procoagulant responses were observed with PAR-1 A allele homozygotes. Clopidogrel significantly inhibited these platelet responses regardless of PAR-1 genotype, but did not offset the hyper-reactivity associated with the A/A homozygotes. We conclude that a common sequence variation within the PAR-1 gene influences TRAP-induced platelet procoagulant activity as well as aggregation. Higher platelet reactivity associated with PAR-1 IVSn–14 A allele homozygotes persists despite clopidogrel therapy. These individuals may be at higher risk of thromboembolic events and may require additional anti-platelet medication.     

Multiple antiplatelet effects of clopidogrel are not modulated by statin type in patients undergoing percutaneous coronary intervention

We investigated whether statin type or dose influenced the inhibition of platelet function induced by clopidogrel in a prospective, open, parallel group study in patients undergoing elective percutaneous coronary intervention. Patients were taking CYP3A4 metabolised atorvastatin (n = 20) or simvastatin (n = 21), non-CYP3A4 metabolised pravastatin (n = 11) or fluvastatin (n = 2), or no statin therapy (n = 5). ADP and TRAP-induced platelet aggregation were measured using optical aggregometry, whole-blood single-platelet counting, and the Ultegra and Plateletworks point-of-care systems. Platelet pro-coagulant activity (annexin V binding and microparticle formation), P-selectin expression and platelet-leukocyte conjugate formation were assessed by flow cytometry. Platelet responses were measured at baseline, 4 h post clopidogrel 300 mg, and after 10 and 28 days with clopidogrel 75 mg daily. Clopidogrel significantly inhibited both ADP and TRAP-induced platelet responses over time, with steady state inhibition achieved by day 10. This was demonstrated by all techniques used. There was no significant effect of statin type or dose on platelet responses by any method at any time-point. In conclusion, statins do not influence the inhibitory effects of clopidogrel on multiple platelet responses, including aggregation, P-selectin expression, platelet-leucocyte conjugate formation and pro-coagulant responses, in patients undergoing elective PCI.     

PAR-1 genotype influences platelet aggregation and procoagulant responses in patients with coronary artery disease prior to and during clopidogrel therapy

Genetic variations of the protease-activated receptor-1 (PAR-1) have been associated with platelet receptor density and linked to thrombin receptor-activating peptide (TRAP)-induced phenotypes of platelet aggregation and P-selectin expression. We investigated whether the PAR-1 intervening sequence-14 A>T dimorphism influences platelet procoagulant activity. We also determined whether the P2Y12 antagonist clopidogrel could offset any observed functional polymorphism of the PAR-1 receptor by inhibiting P2Y12-mediated amplification of TRAP-induced responses. We studied 54 patients listed for elective percutaneous coronary intervention assessing TRAP-induced platelet aggregation and markers of procoagulant activity. Platelet responses were measured at baseline, 4 h post clopidogrel 300 mg, and 10 and 28 days following clopidogrel 75 mg daily. Each patient was genotyped for the PAR-1 intervening sequence-14 A/T dimorphism. Increased platelet aggregation and procoagulant responses were observed with PAR-1 A allele homozygotes. Clopidogrel significantly inhibited these platelet responses regardless of PAR-1 genotype, but did not offset the hyper-reactivity associated with the A/A homozygotes. We conclude that a common sequence variation within the PAR-1 gene influences TRAP-induced platelet procoagulant activity as well as aggregation. Higher platelet reactivity associated with PAR-1 IVSn-14 A allele homozygotes persists despite clopidogrel therapy. These individuals may be at higher risk of thromboembolic events and may require additional anti-platelet medication.     

Is a 300 mg clopidogrel loading dose sufficient to inhibit platelet function early after coronary stenting? A platelet function profile study

BACKGROUND: Clopidogrel combined to aspirin reduces the early risk of stent thrombosis and a clopidogrel pre-treatment strategy is associated with a better outcome. However, in clinical practice such pre-treatment strategy is not always feasible and clopidogrel is frequently not administered until the time of intervention. Aim of the study was to compare platelet function profiles in patients undergoing coronary stenting receiving clopidogrel pre-treatment (75 mg x 2 daily at least 48 hours before intervention) compared to that of patients receiving a 300 mg loading dose at intervention time. METHODS: A total of 50 patients were included in whom patients' platelet aggregation (using light transmittance aggregometry) and platelet activation (P-selectin and PAC-1 expression by whole blood flow cytometry) were assessed following ADP stimuli at baseline, and 4 hours and 24 hours following coronary stenting. RESULTS: In the overall study population, 16/50 (32%) patients were pre-treated with clopidogrel and 34/50 (68%) received clopidogrel loading dose at intervention time. Platelet aggregation, as well as P-selectin and PAC-1 expression were significantly lower in clopidogrel pre-treated patients at baseline (p<0.001) and at 4 hours (p<0.01), while they were similarly inhibited 24 hours after intervention. In conclusion, platelet reactivity of patients treated with clopidogrel front loading at intervention time remains significantly higher than that of pre-treated patients in the early hours after coronary stenting. A higher loading dose at intervention time may be warranted to overcome the early risk of thrombotic complications.     

Influence of statin treatment on platelet inhibition by clopidogrel – a randomized comparison of rosuvastatin,atorvastatin and simvastatin co‐treatment

Objectives. Possible interactions between clopidogrel and atorvastatin, simvastatin or rosuvastatin (a ‘non‐CYP3A4’ metabolized statin) were investigated in a randomized prospective study using sensitive and specific ex vivo platelet function tests. Methods. Patients with coronary artery disease participating in a double‐blind study comparing lipid‐lowering effects of atorvastatin (20–80 mg OD; n = 22) and rosuvastatin (10–40 mg OD; n = 24) were studied before and after 2 weeks treatment with clopidogrel 75 mg OD after completed statin dose titration. In addition, 23 patients were randomized to open‐label simvastatin 40 mg OD. Results. Clopidogrel inhibited 10 μmol L^?1 ADP‐induced platelet aggregation by 40 ± 27%, 57 ± 28% and 51 ± 29%, respectively, in patients on rosuvastatin, atorvastatin and simvastatin treatment. The other platelet tests yielded similar results. No dose‐dependent effects of rosuvastatin or atorvastatin co‐treatment on clopidogrel efficacy were observed. Conclusions. Treatment with CYP3A4 metabolized statins, atorvastatin or simvastatin, did not attenuate the platelet inhibitory effect of clopidogrel maintenance treatment compared with the non‐CYP3A4 metabolized, rosuvastatin.     

他汀类药对氯吡格雷抗血小板作用的影响

目的 前瞻性评价普伐他汀、氟伐他汀、阿托伐他汀对氯吡格雷抗血小板作用的影响.方法 人选连续1015例急性冠状动脉综合征或稳定性心绞痛行冠状动脉造影和(或)支架术患者,分为普伐他汀组(228例)、氟伐他汀组(179例)、阿托伐他汀组(481例)和对照组(127例).比较各组术后支架内血栓发生率、不同浓度(2、5、10、20 μmol)二磷酸腺苷(ADP)诱导的1 min(ADP-1)、5 min(ADP-5)和最大血小板聚集力(ADP-M)及其影响因素.结果 4组患者基础临床情况(除年龄、高血压及冠状动脉造影复查率外)和冠状动脉病变和(或)支架术情况相似,术后支架内血栓发生率(普伐他汀组0.9%、氟伐他汀组1.1%、阿托伐他汀组1.0%、对照组0.8%,P>0.05)和ADP-1、ADP-5、ADP-M与对照组相比差异均无统计学意义(P均>0.05).多因素回归分析显示,年龄(B=0.21,P=0.001)、氯吡格雷总量(B=7.30,P=0.002)及低分子肝素的使用(OR=6.71,P=0.01)是影响氯吡格雷抗血小板作用的独立决定因素.结论 普伐他汀、氟伐他汀和阿托伐他汀对氯吡格雷的抗血小板作用无明显影响,而年龄、氯吡格雷总量及低分子肝素使用是决定氯吡格雷抗血小板作用的独立因素.     

High clopidogrel loading dose during coronary stenting: effects on drug response and interindividual variability.

AIM: To assess platelet inhibitory effects, interindividual variability in platelet inhibition as well as response to a 600 mg, compared to a standard 300 mg, clopidogrel loading dose (LD) after coronary stenting METHODS AND RESULTS: Platelet function profiles were assessed in 50 patients undergoing coronary stenting receiving either a 300 mg (n=27) or 600 mg clopidogrel LD. ADP (6 microM) and collagen (6 microg/mL) induced platelet aggregation, as well as ADP (2 microM) induced glycoprotein (GP) IIb/IIIa activation and P-selectin expression were assessed at baseline and 4, 24, and 48 h following clopidogrel front-loading. A more intense and rapid inhibition of platelet activation (both GP IIb/IIIa activation and P-selectin expression) were achieved using a 600 mg, compared to a 300 mg, LD throughout the entire 48 hours (p<0.001). Although there were no differences in platelet aggregation, overall a 600 mg LD increased the number of clopidogrel responders and this was also achieved earlier compared to a 300 mg LD. A 600 mg LD did not reduce interindividual variability of platelet response. CONCLUSION: The use of a 600 mg clopidogrel LD in patients undergoing coronary stenting optimises platelet inhibitory effects early after intervention and may provide a more effective protection against early thrombotic complications.     

Aspirin and clopidogrel drug response in patients undergoing percutaneous coronary intervention: the role of dual drug resistance.

We evaluated the response to clopidogrel among aspirin-resistant versus aspirin-sensitive patients undergoing elective coronary stenting. Patients (n = 150) treated with aspirin but not clopidogrel had blood samples drawn at baseline and 24 h after clopidogrel loading. Depending on the definition used, 9% to 15% were resistant to aspirin and 24% to clopidogrel. About half of the aspirin-resistant patients were also resistant to clopidogrel. As a group, aspirin-resistant patients had lower response to clopidogrel (assessed by platelet aggregation and activation markers) than aspirin-sensitive patients. Both aspirin- and clopidogrel-resistant patients had higher incidence of creatine kinase-MB elevation than the respective sensitive patients. OBJECTIVES: We sought to evaluate the response to clopidogrel among aspirin-resistant versus aspirin-sensitive patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: Wide variability has been reported in response to aspirin and clopidogrel. There are limited data on the simultaneous responses to both drugs. METHODS: Elective PCI patients (n = 150) who received aspirin for > or = 1 week but not clopidogrel were included. All patients received bivalirudin during PCI. Blood samples were drawn at baseline and 20 to 24 h after a 300-mg clopidogrel dose. Aspirin resistance was defined by > or = 2 of 3 criteria: rapid platelet function analyzer-ASA score > or = 550, 5 micromol/l adenosine diphosphate (ADP)-induced aggregation > or = 70%, and 0.5 mg/ml arachidonic acid-induced aggregation > or = 20%. Clopidogrel resistance was defined as baseline minus post-treatment aggregation < or = 10% in response to 5 and 20 micromol/l ADP. RESULTS: Nineteen (12.7%) patients were resistant to aspirin and 36 (24%) to clopidogrel. Nine (47.4%) of the aspirin-resistant patients were also clopidogrel resistant. Aspirin-resistant patients were more likely to be women and have diabetes than were aspirin-sensitive patients. They also had lower response to clopidogrel, assessed by platelet aggregation and activation markers (flow cytometry-determined PAC-1 binding and P-selectin expression). Elevation of creatine kinase-myocardial band after stenting occurred more frequently in aspirin-resistant versus aspirin-sensitive patients (38.9% vs. 18.3%; p = 0.04) and in clopidogrel-resistant versus clopidogrel-sensitive patients (32.4% vs. 17.3%; p = 0.06). CONCLUSIONS: Aspirin-resistant patients as a group have reduced response to clopidogrel. Furthermore, we have identified a unique group of dual drug-resistant patients who may be at increased risk for thrombotic complications after PCI.     

Effect of atorvastatin and pravastatin on platelet inhibition by aspirin and clopidogrel treatment in patients with coronary stent thrombosis

We sought to determine a potential interaction between statins and antiplatelet therapy with aspirin and clopidogrel. Previous laboratory studies have shown a possible drug-drug interaction of statins metabolized by cytochrome P450 3A4 and clopidogrel (prodrug metabolized by cytochrome P450 3A4), resulting in an impaired inhibitory effect of clopidogrel on platelet aggregation. However, conclusive prospective data assessing this potentially relevant interaction are lacking. In 73 patients, 23 with previous coronary stent thrombosis (ST) (ST group) and 50 without coronary ST (control group), platelet aggregation was measured 3 times in monthly intervals using light transmission aggregometry (adenosine diphosphate [ADP] and arachidonic acid induction). Measurements were carried out with aspirin monotherapy (100 mg/day), dual antiplatelet therapy with aspirin plus clopidogrel (75 mg/day), and additional treatment of 20 mg/day of atorvastatin or 40 mg/day of pravastatin. ADP (5 and 20 micromol)-induced platelet aggregation was significantly decreased with clopidogrel (p <0.001) but remained stable under additional treatment with atorvastatin or pravastatin in the 2 groups. Patients with previous ST showed a higher ADP-induced aggregation level than control subjects. This difference was not influenced by clopidogrel or statin treatment. In conclusion, patients with previous ST show a higher aggregation level than control subjects independent of statin treatment. Atorvastatin and pravastatin do not interfere with the antiaggregatory effect of aspirin and clopidogrel. In conclusion, drug-drug interaction between dual antiplatelet therapy and atorvastatin or pravastatin seems not to be associated with ST.     

Lack of evidence of a clopidogrel-statin interaction in the CHARISMA trial.

OBJECTIVES: The purpose of this study was to evaluate the potential impact of clopidogrel and statin interaction in a randomized, placebo-controlled trial with long-term follow-up. BACKGROUND: There are conflicting data regarding whether statins predominantly metabolized by CYP3A4 reduce the metabolism of clopidogrel to its active metabolite and diminish its clinical efficacy. METHODS: The CHARISMA trial was a randomized trial comparing long-term 75 mg/day clopidogrel versus placebo in patients with cardiovascular disease or multiple risk factors on aspirin. The primary end point was a composite of myocardial infarction, stroke, or cardiovascular death at median follow-up of 28 months. We performed a secondary analysis evaluating the interaction of clopidogrel versus placebo with statin administration, categorizing baseline statin use to those predominantly CYP3A4 metabolized (atorvastatin, lovastatin, simvastatin; CYP3A4-MET) or others (pravastatin, fluvastatin; non-CYP3A4-MET). RESULTS: Of 15,603 patients enrolled, 10,078 received a statin at baseline (8,245 CYP3A4-MET, 1,748 non-CYP3A4-MET) and 5,496 did not. For the overall population, the primary end point was 6.8% with clopidogrel and 7.3% with placebo (hazard ratio [HR] 0.93; p = 0.22). This was similar among patients on CYP3A4-MET (5.9% clopidogrel, 6.6% placebo, HR 0.89; p = 0.18) or non-CYP3A4-MET statin (5.7% clopidogrel, 7.2% placebo, HR 0.78; p = 0.19). There was no interaction between statin types and randomized treatment (p = 0.69). Patients on atorvastatin (n = 4,127) (5.7% clopidogrel, 7.1% placebo, HR 0.80; p = 0.06) or pravastatin (n = 1,440) (5.1% clopidogrel, 7.0% placebo, HR 0.72; p = 0.13) had similar event rates. CONCLUSIONS: Despite theoretic concerns and ex vivo testing suggesting a potential negative interaction with concomitant clopidogrel and CYP3A4-MET statin administration, there was no evidence of an interaction clinically in a large placebo-controlled trial with long-term follow-up.     

氯吡格雷对不稳定型心绞痛患者血小板功能的影响

目的 :观察氯吡格雷对不稳定型心绞痛 （UAP）患者血小板功能的影响 ,探讨其临床应用价值。方法 :UAP患者 85例 ,随机分为氯吡格雷负荷剂量组 （n=30 ） ,氯吡格雷常规剂量组 （n=30 ）及噻氯匹定治疗组 （n=2 5 ）。所有患者在给予阿司匹林 30 0 mg/ d的基础上 ,氯吡格雷负荷剂量组 1次性给予氯吡格雷 （波立维 ） 30 0 mg,氯吡格雷常规剂量组给予波立维 75 mg/ d,噻氯匹定组给予噻氯匹定 （抵克力得 ） 2 5 0 mg/ d,观察 3组患者治疗前 ,氯吡格雷负荷剂量组给药 2 h后 ,氯吡格雷常规剂量组及噻氯匹定组给药 3d后患者血浆 GMP- 14 0含量及血小板最大聚集率（MPAR）的变化。结果 :各组患者治疗后血浆 GMP- 14 0含量及 MPAR较治疗前显著降低 （P<0 .0 1） ,组间血浆GMP- 14 0含量及 MPAR无显著性差异 （P>0 .0 5 ）。结论 :氯吡格雷起效迅速 ,首剂负荷剂量 30 0 mg服药后 2 h即可有效抑制血小板激活 ,可达到服用常规剂量氯吡格雷或噻氯匹定连续 3d抑制血小板激活的效果     

Effects of triple antiplatelet therapy (aspirin, clopidogrel, and cilostazol) on platelet aggregation and P-selectin expression in patients undergoing coronary artery stent implantation

The purpose of this study was to determine the effect of the addition of cilostazol to aspirin plus clopidogrel on platelet aggregation after intracoronary stent implantation. Twenty patients who underwent coronary stent placement were randomly assigned to therapy with aspirin plus clopidogrel (dual-therapy group, n = 10) or aspirin plus clopidogrel plus cilostazol (triple-therapy group, n = 10). A loading dose of clopidogrel (300 mg) and cilostazol (200 mg) was administered immediately after stent placement, and clopidogrel (75 mg/day) and cilostazol (100 mg twice daily) were given for 1 month. Platelet aggregation in response to adenosine diphosphate (ADP; 5 and 20 micromol/L) or collagen and P-selectin (CD-62P) expression was assayed at baseline, 2 hours, 24 hours, 1 week, and 1 month after stent placement. Inhibition of ADP-induced platelet aggregation was significantly higher in patients receiving triple therapy than those receiving dual therapy from 24 hours after stent placement, and inhibition of collagen-induced platelet aggregation was significantly higher in the triple-therapy group beginning 1 week after stent placement. P-Selectin expression was significantly lower in the triple-therapy than dual-therapy group at 1 week and 30 days. In conclusion, compared with dual antiplatelet therapy, triple therapy after coronary stent placement resulted in more potent inhibition of platelet aggregation induced by ADP and collagen. These findings suggest that triple therapy may be used clinically to prevent thrombotic complications after coronary stent placement.     

Markers of inflammation and platelet aggregation in patients with non ST elevation acute coronary syndrome treated with atorvastatin or pravastatin

AIM: To find out whether early use of atorvastatin and pravastatin in patients with non-ST elevation acute coronary syndrome is associated with rapid changes of platelet aggregation and plasma levels of markers of inflammation. MATERIAL AND METHODS: Ninety patients (<24h from pain onset, age 64+/-10 years) treated with aspirin and heparin were randomized to open atorvastatin 10 mg/day (n=30), atorvastatin 40 mg/day (n=29) or pravastatin 40 mg/day (n=31). Spontaneous and ADP induced platelet aggregation (light transmission), plasma levels of interleukin 6 (IL-6) and C-reactive protein (CRP) (immunoassay) were assessed at baseline, on days 7 and 14. RESULTS: Baseline clinical characteristics, platelet aggregation parameters, CRP and IL-6 levels were similar in all groups. In all groups levels of total and low-density lipoprotein (LDL) cholesterol (CH) were lowered by days 7 (p<0.01) and 14 (p<0.01 vs. baseline and for both atorvastatin groups vs. day 7). Spontaneous platelet aggregation decreased by 15% from baseline, p<0.01, on day 14 in patients receiving atorvastatin 40 and was unchanged in other groups. Changes of ADP induced platelet aggregation, IL-6 and CRP levels were not significant in all groups. However combination of 2 atorvastatin groups (n=59) revealed decrease of CRP by 18% from baseline on day 14 (from 6.94+/-0.97 to 4.76+/-0.76 mg/l, p=0.028). No correlations were found between changes of LDL CH and those of other parameters. CONCLUSION: In otherwise conventionally treated patients with non-ST elevation acute coronary syndrome early use of atorvastatin was associated with rapid (in 14 days) decrease of CRP level. Higher dose of atorvastatin (40 mg/day) induced favorable changes of spontaneous platelet aggregation. There were no significant changes of parameters studied in pravastatin treated patients.