Plasma From Patients Undergoing Liver Transplantation Is Resistant to Anticoagulant Activity of Soluble Thrombomodulin

Recombinant human soluble thrombomodulin (ART‐123) is an anticoagulant and anti‐inflammatory agent clinically used for treatment of disseminated intravascular coagulation. Preclinical studies have shown that ART‐123 reduces hepatic ischemia/reperfusion. Although ART‐123 may therefore have clinical benefit in orthotopic liver transplantation, the substantial alterations in the hemostatic system may complicate its use in this setting. Here, we studied the in vitro effect of ART‐123 on coagulation of patients with end‐stage liver disease undergoing liver transplantation. Ten patients with end‐stage liver disease undergoing liver transplantation were included in this study. Plasma samples of 10 healthy individuals were included to establish reference values. Different concentrations of ART‐123 were added to plasma samples, and peak thrombin generation and clot lysis times (CLTs) were determined. In patient samples, plasma was profoundly resistant to the anticoagulant action of ART‐123, as reflected by significantly higher median inhibitory concentration (IC(50)) values of peak thrombin generation compared with controls. This might be partially explained by low levels of protein C, protein S, and elevated levels of factor VIII during transplantation. Intraoperative levels of thrombin activatable fibrinolysis inhibitor were significantly lower when compared with controls. However, ART‐123–dependent prolongation of CLTs was not significantly different from healthy controls. In conclusion, this study suggests that ART‐123 is unlikely to provoke bleeding in patients undergoing liver transplantation because proposed clinical dosages have a virtually absent anticoagulant effect in these patients. Clinical studies are required to confirm the safety of ART‐123 and efficacy on alleviating ischemia/reperfusion injury during liver transplantation.