阿司匹林和氯吡格雷抵抗的研究进展

近来阿司匹林和氯吡格雷抵抗受到了越来越多的关注,它被用来描述冠状动脉疾病患者在用阿司匹林和氯吡格雷抗血小板治疗后仍发生不良心血管事件。明确抵抗的原因和机制将使冠状动脉疾病患者受益匪浅。现就阿司匹林和氯吡格雷抵抗的定义、可能机制和检测方法做一综述。     

氯吡格雷抵抗研究进展

氯吡格雷的抗血小板聚集作用在急性冠脉综合征和经皮冠状动脉介入术患者中得到广泛应用,但氯吡格雷抵抗的出现影响了其临床疗效。现就氯吡格雷抵抗的定义、临床意义、血小板聚集检测方法、发生机制及防治策略分别加以阐述。     

氯吡格雷抵抗相关因素的研究进展

临床上部分冠状动脉性心脏病患者未从氯吡格雷抗血小板治疗中获益,这就是氯吡格雷抵抗现象。氯吡格雷抵抗反映氯吡格雷抗血小板治疗失败。研究表明,氯吡格雷抵抗可能与血栓事件复发密切相关。它可能受多个因素影响,主要分为内源性和外源性两方面。现就氯吡格雷抵抗的检测方法、影响因素及临床对策进行了详细综述。     

他汀类药物对氯吡格雷抵抗的影响

双联抗血小板治疗被广泛应用于冠状动脉疾病的治疗,尤其是急性冠状动脉综合征(ACS)或经皮冠状动脉介入治疗(PCI)术后患者。其中一部分应用氯吡格雷治疗患者由于对氯吡格雷反应性差而未达到很好的治疗效果,这就是"氯吡格雷抵抗"现象。近年通过对不同他汀类药物种类、药物剂量、联用时其他因素的干扰等研究表明,他汀类药物直接独立影响个体对氯吡格雷抗血小板的反应证据不足,但这些研究为进一步研究氯吡格雷抵抗机制及明确他汀类药物与氯吡格雷相互作用提供依据,从而指导临床医师及时调整抗血小板治疗患者的用药方案,以避免恶性血栓栓塞事件发生,本文综述了他汀类药物与氯吡格雷的相互作用。     

氯吡格雷抵抗的临床研究进展

氯吡格雷是一种抗血小板药物,是新型二磷酸腺苷受体拮抗剂,已广泛应用于各种血栓性疾病尤其是急性冠脉综合征和经皮冠状动脉介入治疗术后的抗血栓治疗。但近年来,在长期随访中研究发现,部分患者存在氯吡格雷抵抗现象,即应用氯吡格雷治疗的患者仍会发生心血管血栓事件。本文就氯吡格雷的作用机制、氯吡格雷抵抗定义、氯吡格雷抵抗韵发生机制及临床意义等作一综述。     

氯吡格雷治疗后血小板高反应性研究现状

<正>氯吡格雷是目前冠状动脉支架术后抗血小板治疗的基石,在美国食品与药物管理局(FDA)批准普拉格雷之前,氯吡格雷是惟一被指南推荐使用的噻吩吡啶类抗血小板药物。然而,即使接受足量、长期的氯吡格雷治疗,部分患者仍有心脑血管血栓事件发生,谓之"氯吡格雷抵抗"。氯吡格雷抵抗     

氯吡格雷抵抗的实验室诊断及临床价值

氯吡格雷与阿司匹林双联抗血小板治疗可显著减少接受经皮冠状动脉介入(PCI)治疗冠心病患者的心血管事件。然而,氯吡格雷的疗效存在显著的个体差异,氯吡格雷抵抗是引起冠心病PCI患者血栓事件的重要原因之一。当前,针对氯吡格雷抵抗患者的管理策略尚未达成共识。临床是否应针对氯吡格雷抵抗进行常规血小板功能检测,以指导抗血小板药物的应用尚存在广泛争议。该文汇总了近年氯吡格雷抵抗的相关研究结果,主要介绍氯吡格雷抵抗的实验室诊断及临床价值。     

氯吡格雷抵抗

氯吡格雷是目前广泛应用的抗血小板药物，其对血小板的抑制具有个体差异。氯吡格雷抵抗的定义，国际上尚缺乏一致性标准。氯吡格雷抵抗的出现已影响其疗效发挥，氯吡格雷抵抗的机制迄今尚未完全阐明。本文试对其定义、发生率、氯吡格雷抵抗机制及临床意义作一综述。     

应用血栓弹力图评估ACS患者替格瑞洛与氯吡格雷抗血小板的疗效

目的通过血栓弹力图(TEG)检测血小板聚集率,观察接受双联抗血小板药物治疗的急性冠状动脉综合征(ACS)患者应用替格瑞洛或氯吡格雷的抗血小板疗效。方法选取清华大学第一附属医院心脏中心住院的84例急性冠状动脉综合征患者,随机分为两组,氯吡格雷组(n=42)与替格瑞洛组(n=42),通过TEG检测方法比较两组患者服用氯吡格雷和替格瑞洛后的血小板抑制率情况。结果氯吡格雷组中11例出现氯吡格雷抵抗,发生率为26.19%,替格瑞洛组中1例患者出现替格瑞洛抵抗,发生率为2.38%,两组发生率的比较差异有统计学意义(χ2=9.722,P=0.002);氯吡格雷组中有1例(2.38%)发生阿司匹林抵抗;替格瑞洛组中有2例(4.76%)发生阿司匹林抵抗,两者发生率比较差异无显著统计学意义(χ2=0.346,P=0.557)。结论接受标准抗血小板治疗的部分急性冠状动脉综合征患者存在抗血小板抵抗,TEG监测结果显示,替格瑞洛的抗血小板聚集效果明显优于氯吡格雷。     

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。     

Aspirin and clopidogrel resistance: an emerging clinical entity.

Antiplatelet therapy is a cornerstone of cardiovascular medicine. Aspirin and clopidogrel have emerged as critical therapies in the treatment of cardiovascular disease. Despite their efficacy, patients on these medications continue to suffer complications. Millions of patients are currently on low-dose antiplatelet therapy but it is unknown how many of these patients are under-treated or on the wrong medication. Aspirin and clopidogrel resistance are emerging clinical entities with potentially severe consequences such as recurrent myocardial infarction, stroke, or death. The mechanism of resistance remains incompletely defined, but there are specific clinical, cellular, and genetic factors that influence therapeutic failure. These factors range from physicians who fail to prescribe these medications despite appropriate indications to polymorphisms of platelet membrane glycoproteins. Rapid and accurate diagnosis of antiplatelet resistance also remains an issue as new bedside tests are developed. By understanding the mechanism of therapeutic failure and by improving the diagnosis of this clinical entity, a new era of individualized antiplatelet therapy may arise with routine measurements of platelet activity in the same way that cholesterol, blood pressure, and blood sugar are followed, thus improving the care for millions of people.     

阿司匹林抵抗研究存在的问题与展望

阿司匹林是心血管疾病治疗的关键用药之一。虽然它能有效的抗血小板聚集,但是有些患者经过长期随访仍有心血管事件发生,称为阿司匹林抵抗。阿司匹林抵抗的机制不明确,而且缺乏快速的、临床实用的、准确的检测方法。通过进一步研究阿司匹林抵抗的机制和临床特征,我们应该象监测胆固醇、血压、血糖一样,监测血小板活性而指导患者进行个体化的抗血小板治疗,从而提高此类患者的治疗效果。     

Resistenz gegenüber Plättchenfunktionshemmern: ein reales klinisches Problem

The benefit of dual antiplatelet therapy with acetylsalicylic acid and clopidogrel in cardiovascular risk patients has been documented by several studies. Patients undergoing coronary interventions are in jeopardy of periinterventional thrombotic complications, and stent thrombosis, although a rare event, is still a serious problem, especially in the era of drug-eluting stents. Recently, there is a growing body of evidence that response to antiplatelet therapy is a clinically important entity and subjects presenting a low response to conventional antiplatelet substances are at increased risk for atherothrombotic events. Thereby, aspirin and clopidogrel resistance have been considered a multifactorial phenomenon underlying factors ranging from nonadherence of patients to antiplatelet therapy to demographic characteristics (age, diabetes, renal failure, etc.), acute coronary syndromes as well as genetic polymorphisms involving platelet glycoproteins and cytochrome P450 isoenzymes. The introduction of point-of-care platelet function tests into clinical routine is a still ongoing process, partly because of missing common definitions of resistance, partly due to different laboratory methods that prevent transferability of results. However, first approaches of an adoption of antiplatelet therapy guided by platelet function analysis provide promising results that an individualized antiplatelet strategy might help to improve platelet inhibition in cardiovascular patients. If this will improve clinical outcome has to be evaluated in upcoming studies. The aim of the present article is to give a review about the clinical relevance of resistance to antiplatelet therapy and alternative treatment options.     

Aspirin and Clopidogrel: Efficacy, Treatment, and Resistance in Coronary Artery Disease

Oral antiplatelet therapy is a key element of the continuously evolving treatment of acute coronary syndromes. As part of this evolution, resistance to oral antiplatelet therapy has emerged as a new challenge adversely affecting patients’ clinical risk and outcome. This review addresses the role of two oral antiplatelet therapy agents, aspirin and clopidogrel, their mechanism of action, and the evidence supporting their use in the setting of coronary artery disease. Unfortunately, clinically relevant resistance to aspirin and clopidogrel exists. Resistance may indicate a higher risk for major adverse events. An established safe and reliable treatment alternative is lacking at this point; further research is needed to evaluate the efficacy of any alternative treatments that can be offered to decrease cardiovascular risk and improve clinical outcomes.     

Prasugrel loading dose in diabetic patients with acute STEMI – Always sufficiently effective? Observation in two cases and review of current knowledge

The activation and subsequent platelet aggregation play a key role in the formation of arterial thrombosis and therefore is the key therapeutic target in the treatment of acute coronary syndromes. Dual antiplatelet therapy containing aspirin and P2Y12 ADP receptor antagonist forms currently the basis in acute ST – elevation myocardial infarction (STEMI) pharmacological treatment. Nevertheless, there is a wide variability in pharmacodynamic response to administration of clopidogrel, the most frequently used P2Y12 ADP receptor antagonist. High platelet reactivity after clopidogrel administration is associated with increased risk of stent thrombosis and points to the suitability of laboratory monitoring of antiplatelet therapy efficacy in clinical practice. Laboratory monitoring of antiplatelet therapy by ex vivo platelet function tests may help to identify individuals with poor antiplatlet response. Recently, there is a growing number of data reporting a failure in antiplatelet response following clopidogrel administration, which is specifically associated with insulin resistance and diabetes mellitus. Prasugrel, a new, potent P2Y12 ADP receptor antagonist, provides faster and more consistent inhibition of platelet function compared with clopidogrel. Prasugrel therapy was repeatedly described as an effective method to overcome clopidogrel resistance and prasugrel resistance has not yet been reliably described. We report two cases of patients with diabetes mellitus type 2 at the stage of organ complications, in whom a prasugrel loading dose of 60 mg did not reach adequate antiplatelet response in 60 min after prasugrel administration. The antiplatelet response was measured by light transmission aggregometry and by VASP protein phosphorylation assessment.     

Variable response to clopidogrel in patients with coronary artery disease

Antiplatelet drug resistance is a multifactorial phenomenon that affects a large number of cardiovascular patients with symptomatic coronary artery disease. Although unique definitions for aspirin and clopidogrel resistance are missing, there is growing evidence for a clinical importance of response to antiplatelet therapy. The prevalence for aspirin and clopidogrel resistance has been reported to be between 5 and 30% in literature. Moreover, recent data suggest a high rate of dual antiplatelet drug resistance. Although there are convincing data about an association of aspirin resistance and clinical outcome, little is known about the clinical relevance of clopidogrel hyporesponsiveness. This article reviews the evidence for the clinical impact of antiplatelet drug resistance, with particular attention on the clinical outcome of clopidogrel low response according to current clinical data. Additional systematic studies are needed to evaluate the effects of alternative antiplatelet therapies in patients identified as low responders.     

Recent developments in the use of antiplatelet agents to prevent cardiovascular events

Platelets are pivotal contributors to arterial thrombosis. Dual antiplatelet therapy with aspirin and clopidogrel has become the standard of care for the secondary prevention of cardiovascular events in patients with acute coronary syndromes and after percutaneous coronary intervention. Clinical evidence of the continued risk of cardiovascular events plus pharmacodynamic evidence of substantial variability in on-treatment platelet reactivity has supported the development of new therapeutic strategies, using established agents and new antiplatelet drugs. This article will highlight recent pivotal clinical trials seeking to advance the use of antiplatelet therapy in patients with cardiovascular disease.     

Antiplatelet and Anticoagulant Therapies in Acute Coronary Syndromes

The combination of aspirin and clopidogrel is the mainstay antiplatelet therapy for acute coronary syndromes (ACS). However, the dosing of aspirin, the dosing of clopidogrel, the timing of clopidogrel initiation as well as the duration of clopidogrel therapy remain controversial matters. Clopidogrel resistance is an emerging concept with potential clinical implications. In the era of clopidogrel and bivalirudin, the role of glycoprotein IIb/IIIa antagonists is being challenged, yet they are still indicated in a select high-risk population. Concerning anticoagulant use in ACS, newer agents, bivalirudin and fondaparinux, have improved outcomes in comparison to heparin in patients managed with an invasive or conservative strategy, respectively. Combining multiple antiplatelet agents and an anticoagulant is the standard of care for ACS.     

Update: orale Thrombozyteninhibitoren in der Kardiologie

The antithrombotic therapy in patients with atherosclerotic vascular disease is subject of several new therapeutic approaches. Simultaneous treatment with acetylsalicylic acid (ASS) and a thienopyridin (clopidogrel) represents the standard of care for patients with acute coronary syndrome and following coronary stenting recommended by many guidelines. Without true evidence this drug combination is used for the prevention of arterial thrombosis in many other vascular interventions (e.g. carotid or aortic stenting). The main problems of this dual antiplatelet therapy are the slow onset of action and the high interindividual variation in the degree of platelet inhibition. The thienopyridin prasugrel is a more potent platelet inhibitor with a more rapid onset of action and smaller interindividual variations in platelet inhibition. The therapeutic superiority of prasugrel was proven in patients with acute coronary syndrome undergoing coronary interventions. As a higher rate of bleeding complications was seen in patient subgroups further clinical studies with prasugrel are ongoing. Newer developments are focusing on ticagrelor, a new ADP-receptor antagonist, which has been proven superior to clopidogrel in clinical studies and triple therapy utilizing ASS, clopidogrel, and one of the new highly specific antithrombotics (e.g. factors Xa-antagonists or direct thrombin inhibitors).