Klinik für Anästhesiologie und Intensivmedizin, Universitätsklinkum Essen, Universität Duisburg-Essen, Hufelandstrasse 55, D-45122 Essen, Germany.
Best Pract Res Clin Anaesthesiol. 2012 Jun;26(2):179-98. doi: 10.1016/j.bpa.2012.04.003.
The incidence of bleeding and thrombo-embolic complications in patients undergoing mechanical circulatory support therapy remains high and is associated with bad outcomes and increased costs. The need for anticoagulation and anti-platelet therapy varies widely between different pulsatile and non-pulsatile ventricular-assist devices (VADs) and extracorporeal membrane oxygenation (ECMO) systems. Therefore, a unique anticoagulation protocol cannot be recommended. Notably, most thrombo-embolic complications occur despite values of conventional coagulation tests being within the targeted range. This is due to the fact that conventional coagulation tests such as international normalised ratio (INR), activated partial thromboplastin time (aPTT) and platelet count cannot detect hyper- or hypofibrinolysis, hypercoagulability due to tissue factor expression on circulating cells or increased clot firmness, and platelet aggregation as well as response to anti-platelet drugs. By contrast, point-of-care (POC) whole blood viscoelastic tests (thromboelastometry/-graphy) and platelet function tests (impedance or turbidimetric aggregometry) reflect in detail the haemostatic status of patients undergoing mechanical circulatory support therapy and the efficacy of their anticoagulation and antiaggregation therapy. Therefore, monitoring of haemostasis using POC thromboelastometry/-graphy and platelet function analysis is recommended during mechanical circulatory support therapy to reduce the risk of bleeding and thrombo-embolic complications. Notably, these haemostatic tests should be performed repeatedly during mechanical circulatory support therapy since thrombin generation, clot firmness and platelet response may change significantly over time with a high inter- and intra-individual variability. Furthermore, coagulation management can be hampered in non-pulsatile VADs by acquired von Willebrand syndrome, and in general by acquired factor XIII deficiency as well as by heparin-induced thrombocytopenia. In addition, POC testing can be used in bleeding patients to guide calculated goal-directed therapy with allogeneic blood products, haemostatic drugs and coagulation factor concentrates to optimise the haemostasis and to minimise transfusion requirements, transfusion-associated adverse events and to avoid thrombo-embolic complications, as well. However, coagulation management in patients undergoing mechanical circulatory support therapy is somehow like navigating between Scylla and Charybdis, and development of protocols based on POC testing seems to be beneficial.
在接受机械循环支持治疗的患者中，出血和血栓栓塞并发症的发生率仍然很高，并且与不良结局和增加的成本相关。不同的脉动和非脉动心室辅助装置（VAD）和体外膜氧合（ECMO）系统之间，抗凝和抗血小板治疗的需求差异很大。因此，不能推荐一种独特的抗凝方案。值得注意的是，尽管常规凝血试验值在目标范围内，但大多数血栓栓塞并发症仍会发生。这是因为常规凝血试验，如国际标准化比值（INR）、部分激活凝血活酶时间（aPTT）和血小板计数，无法检测到高纤维蛋白溶解或低纤维蛋白溶解、循环细胞表面组织因子表达导致的高凝状态或增加的凝块硬度，以及血小板聚集和对抗血小板药物的反应。相比之下，即时检测（POC）全血粘弹性试验（血栓弹力描记术/图）和血小板功能试验（阻抗或比浊聚集测定法）详细反映了接受机械循环支持治疗的患者的止血状态和抗凝和抗聚集治疗的疗效。因此，建议在机械循环支持治疗期间使用 POC 血栓弹力描记术/图和血小板功能分析来监测止血，以降低出血和血栓栓塞并发症的风险。值得注意的是，由于凝血酶生成、凝块硬度和血小板反应可能随时间显著变化，具有较高的个体内和个体间变异性，因此在机械循环支持治疗期间应重复进行这些止血试验。此外，非脉动 VAD 中可获得性血管性血友病，以及一般的获得性因子 XIII 缺乏症以及肝素诱导的血小板减少症，可能会阻碍凝血管理。此外，POC 检测可用于出血患者，以指导计算导向的治疗，使用同种异体血液制品、止血药物和凝血因子浓缩物，以优化止血，并最大限度地减少输血需求、输血相关不良事件，并避免血栓栓塞并发症。然而，接受机械循环支持治疗的患者的凝血管理有点像在 Scylla 和 Charybdis 之间航行，基于 POC 检测的方案似乎是有益的。
