DEVELOPMENT OF A NOVEL WHOLE BLOOD COAGULATION ASSAY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在过去的40年里，我们对血液凝固的理解发生了显著的变化。新的、更有效的抗血小板和抗凝药物已经推出。尽管药物疗法不断创新，但我们的止血标准实验室化验并不能反映我们对凝血机制的新见解，也不能作为这些新药的适当实验室监测。目前的临床实验室分析是在不含血小板的血浆样本上进行的。越来越明显的是，全血是分析凝血的最合适的患者样本。血液动力学止血分析系统(H.A.S.)使用定量物理技术分析全血样本。先前的研究表明，H.A.S测量的参数不仅反映了血液凝块的结构质量，还反映了凝块形成过程中的血小板功能。H.A.S是第一个定量评估血栓形成过程中的血小板功能的体外系统。 由于最近推出了非常有效的抗血小板和抗凝药物，监测它们的效果的能力变得越来越重要。这些强效药物在疗效和毒性之间的治疗窗口非常窄。虽然它们能有效控制高凝状态下的血栓形成，但它们的相对效力增加了大出血的风险。遗憾的是，常规监测参数(即PT、aPTT、INR)不能衡量或预测疗效或毒性。因此，临床医生不能充分(或安全地)监测这些新药疗法的安全性或有效性。虽然一些抗凝剂(如低分子肝素(LMWH))的常规监测对于正常患者可能不是必要的，但对于同时存在出血危险因素的复杂患者(例如，肝或肾功能障碍患者)，记录充分和安全的临床反应的重要性至关重要。我们在终末期肾病(ESRD)受试者中进行的令人信服的初步数据显示，暴露于低分子肝素依诺肝素后抗凝反应增强。 对于这些特殊人群，临床医生迫切需要一种廉价的检测方法，能够快速测量疗效并预测毒性风险。我们相信H.A.S.可以发挥这一作用，并改善对这些患有凝血障碍的特殊人群的护理。通过这样做，这将使临床医生能够量身定做抗凝治疗，以实现成功的结果，同时防止不良出血事件。这些结果应该会降低医疗成本。 这项研究有两个具体目的。第一项涉及使用血液动力学止血分析系统，以确定在两组受试者中，在增加依诺肝素(0.25、0.50和1.0 mg/kg)剂量后，体内抗凝血因子Xa活性与凝血酶生成时间(TGT)的关系：1)没有肾功能障碍的正常健康受试者；2)终末期肾病(ESRD)维持血液透析的受试者(ESRD；肌酐清除；10毫升/分钟)。第二个目标是确定Hemodyne止血分析系统在单剂量依诺肝素1 mg/kg后12小时内(对照组与ESRD组)凝血酶生成时间的组间差异。 所有以前和现在的血小板功能测量都必须与凝血一起进行。通过表征这些重要的凝血参数，H.A.S是一种灵敏、新颖的全血检测方法，可以监测各种疾病状态和接受抗凝治疗的患者的凝血状态。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Over the last 40 years, our understanding of blood coagulation has changed significantly. Newer, more potent antiplatelet and anticoagulant medications have been introduced. Despite the innovation of drug therapy, our standard laboratory assays of hemostasis do not reflect our new insights into the clotting mechanism, and do not serve as adequate laboratory monitors for these new drugs. Current clinical laboratory assays are performed on plasma samples that do not contain platelets. It is becoming increasingly apparent that whole blood is the most appropriate patient sample for analyzing coagulation. The Hemodyne Hemostasis Analysis System (H.A.S.) analyzes whole blood samples using quantitative physical techniques. Previous investigations have shown that the parameters measured by the H.A.S. reflect not only the structural qualities of the blood clot, but also platelet function during clot formation. The H.A.S. is the first ex vivo system to quantitatively assess platelet function during clot formation. Due to the recent introduction of very potent antiplatelet and anticoagulant medications, the ability to monitor their effects is increasingly important. These potent drugs have a very narrow therapeutic window between efficacy and toxicity. Although they effectively control thrombosis in hypercoagulable conditions, their relative potency increases the risk of major hemorrhage. Unfortunately conventional monitoring parameters (i.e., PT, aPTT, INR) cannot measure or predict efficacy or toxicity. Thus, clinicians cannot adequately (or safely) monitor these new drug therapies for safety or efficacy. While the routine monitoring of some anticoagulants (such as low molecular weight heparin (LMWH)) may not be necessary in normal patients, the importance of documenting adequate and safe clinical response is critical in complex patients with concurrent risk factors for hemorrhage (e.g., patients with hepatic or renal dysfunction). We have compelling preliminary data conducted in end-stage renal disease (ESRD) subjects that demonstrate an enhanced anticoagulant response following exposure to the LMWH enoxaparin. For these special populations, clinicians desperately need an inexpensive assay that can quickly measure efficacy and predict risk of toxicity. We believe the H.A.S. can serve this role, and improve the care to these special populations with coagulation disorders. By doing so, this would allow clinicians to tailor anticoagulant therapy to achieve successful outcomes while preventing adverse bleeding events. These outcomes should result in reduced healthcare costs. This study has two specific aims. The first involves using the Hemodyne Hemostasis Analysis System , to define the in vivo relationship of antifactor Xa activity to thrombin generation time (TGT) following increasing doses of enoxaparin (0.25, 0.50 and 1.0 mg/kg) in two groups of subjects: 1) normal, healthy subjects without renal dysfunction; and 2) subjects with end-stage renal disease (ESRD; creatinine clearance < 10 mL/min) on maintenance hemodialysis. The second goal is to determine the ability of the Hemodyne Hemostasis Analysis System to characterize intergroup (control versus ESRD) differences in thrombin generation time over 12 hours following single dose enoxaparin 1 mg/kg. All previous and current measures of platelet function must be performed with clotting by characterizing these important clotting parameters, the H.A.S. is a sensitive, novel, whole blood assay that monitors coagulation status in various disease states and in patients on anticoagulant therapy.