Porte R J
Department of Surgery, Westeinde Hospital, The Hague, The Netherlands.
Semin Thromb Hemost. 1993;19(3):191-6. doi: 10.1055/s-2007-994025.
Bleeding in OLT is related to two different mechanisms. There is no doubt that the extensive surgical trauma plays a critical role in the origin of serious bleeding. However, this bleeding can be aggravated by defects in the hemostasis system. Hemostasis defects can be divided into those present before the operation and secondary to the underlying liver disease and those originating during the operation. Intraoperative defects can be classified according to the three main systems of hemostasis: coagulation, fibrinolysis, and platelet function. Serious problems with coagulation are clearly related to the quality of the graft and are less frequent now since better graft preservation techniques have been introduced. Adequate intraoperative monitoring and substitution therapy with plasma products is also important in controlling coagulation defects. However, problems resulting from hyperfibrinolysis seem to be of clinical importance, especially during the anhepatic stage and after graft reperfusion. While lack of hepatic clearance seems to be an important cause of t-PA increase during the anhepatic stage, enhanced release may be important for the rise after graft reperfusion. There is also evidence that decreased platelet numbers and function, especially after graft reperfusion, play a role. The clinical relevance of this finding remains to be elucidated. Finally, it has recently been demonstrated that antifibrinolytic agents may reduce intraoperative blood loss. However, the effect of aprotinin and other antifibrinolytic agents has still to be confirmed by randomized clinical studies. Future scientific research should focus on the mechanisms underlying the hemostasis defects. It can be expected that these efforts may finally result in a further reduction in the usage of blood products during liver transplantation.
肝移植术中出血与两种不同机制有关。毫无疑问，广泛的手术创伤在严重出血的发生中起关键作用。然而，止血系统的缺陷会加重这种出血。止血缺陷可分为术前存在且继发于潜在肝脏疾病的缺陷以及手术过程中产生的缺陷。术中缺陷可根据止血的三个主要系统进行分类：凝血、纤维蛋白溶解和血小板功能。凝血方面的严重问题显然与移植物的质量有关，由于引入了更好的移植物保存技术，现在这种情况较少见。术中进行充分的监测以及用血浆制品进行替代治疗对于控制凝血缺陷也很重要。然而，纤维蛋白溶解亢进导致的问题似乎具有临床重要性，尤其是在无肝期和移植物再灌注后。虽然缺乏肝脏清除似乎是无肝期组织型纤溶酶原激活物（t-PA）增加的一个重要原因，但移植物再灌注后的升高可能与释放增强有关。也有证据表明血小板数量和功能的下降，尤其是在移植物再灌注后，起了一定作用。这一发现的临床相关性仍有待阐明。最后，最近已证明抗纤维蛋白溶解剂可能减少术中失血。然而，抑肽酶和其他抗纤维蛋白溶解剂的效果仍需通过随机临床研究来证实。未来的科学研究应聚焦于止血缺陷的潜在机制。可以预期，这些努力最终可能会进一步减少肝移植期间血液制品的使用。
