Premkumar Madhumita, Kulkarni Anand V, Kajal Kamal, Divyaveer Smita
Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012, India.
Department of Hepatology, Asian Institute of Gastroenterology, Hyderabad, India.
J Clin Exp Hepatol. 2022 Mar-Apr;12(2):533-543. doi: 10.1016/j.jceh.2021.05.001. Epub 2021 May 8.
Standard coagulation tests such as prothrombin time, activated partial thromboplastin time, and international normalized ratio are determined by liver-synthesized coagulation factors. Despite an increased international normalized ratio, patients with cirrhosis are in a "rebalanced" state of hemostasis as the concomitant effect of reduced protein C, protein S, and thrombomodulin is not evaluated in standard coagulation tests. The cell-based model of hemostasis indicates additional mechanisms such as systemic inflammation, sepsis, and organ failures tip the delicate coagulation balance to an anticoagulant type in acute-on-chronic liver failure. In acute liver failure, thrombin generation and platelet function remain intact despite a marked prolongation in prothrombin time. We aimed to explain the principles, application, and utility of viscoelastic tests such as thromboelastography, rotational thromboelastometry, and Sonoclot.
We reviewed the available literature from MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trial with the search terms 'coagulation', 'cirrhosis', 'acute-on-chronic liver failure', 'thromboelastography', 'thromboelastometry' and 'sonoclot' for cross sectional studies, cohort studies and randomized trials.
The point-of-care viscoelastic tests provide actionable targets for correcting the coagulation defect in a patient with bleeding and provide evidence-based algorithms for use in liver disease. A limitation of these tests is the inability to assess vessel injury and endothelial elements.
Global coagulation tests provide a comprehensive estimate of coagulation in vitro; however, their use has only been validated in the setting of liver transplantation. Newer guidelines for hemostatic resuscitation are now accepting these POC tests, but additional data are required to validate their use as standard of care.
诸如凝血酶原时间、活化部分凝血活酶时间及国际标准化比值等标准凝血试验是由肝脏合成的凝血因子所决定的。尽管国际标准化比值升高，但肝硬化患者处于止血的“再平衡”状态，因为标准凝血试验未评估蛋白C、蛋白S和血栓调节蛋白减少的伴随效应。基于细胞的止血模型表明，诸如全身炎症、脓毒症及器官功能衰竭等其他机制会使急性慢性肝衰竭中脆弱的凝血平衡倾向于抗凝类型。在急性肝衰竭中，尽管凝血酶原时间显著延长，但凝血酶生成及血小板功能仍保持完整。我们旨在解释诸如血栓弹力图、旋转血栓弹力测定法及声凝分析等粘弹性试验的原理、应用及效用。
我们检索了MEDLINE、EMBASE及Cochrane对照试验中心注册库中可用的文献，搜索词为“凝血”“肝硬化”“急性慢性肝衰竭”“血栓弹力图”“血栓弹力测定法”及“声凝分析”，以查找横断面研究、队列研究及随机试验。
即时粘弹性试验为纠正出血患者的凝血缺陷提供了可操作的靶点，并为肝病的应用提供了循证算法。这些试验的一个局限性是无法评估血管损伤及内皮成分。
整体凝血试验在体外对凝血进行全面评估；然而，其应用仅在肝移植背景下得到验证。新的止血复苏指南现正接受这些即时检验，但需要更多数据来验证其作为护理标准的应用。
