• anticoagulant therapy;
  • hemorrhage;
  • heparin;
  • liver transplantation;
  • living donor;
  • thrombosis

Abstract:  Heparin is widely used to reduce the incidence of vascular thrombosis after liver transplantation. Appropriate use of heparin based on changes in coagulation and fibrinolytic profiles, however, has not yet been discussed in detail. We performed living-donor liver transplantation for 128 adult patients. In this series, dalteparin (25 IU/kg/d) was administered until post-operative day (POD) 2. On POD 3, the anticoagulant drug was changed to heparin (unfractionated heparin sodium, 5000 U/d), the dose of which was changed according to the level of activated clotting time (ACT) targeted between 130 and 160 s. The plasma level of plasmin-alpha2 plasmin inhibitor complex, thrombin-antithrombin III complex (TAT), and fibrin degradation product D-dimer (FDP-DD) were monitored in the 21 patients. Predictors for heparin doses were analyzed among clinical parameters (n = 128). Four patients (3%) were complicated with thrombosis despite the above-mentioned anticoagulation protocol. Transfusion and/or relaparotomy for hemostasis were necessary for bleeding in 19 patients (15%). The TAT level markedly elevated until POD 3 and FDP-DD peaked later. The required heparin dose to maintain adequate ACT levels increased linearly until POD 8, and kept constant thereafter, which correlated with the weight of the liver graft (p = 0.01). Thus, frequent monitoring of the heparin dosage is necessary to keep the ACT level in the target range in the first post-operative week. High hemorrhage complications in our series indicate that the lower target ACT range may be preferable in the second post-operative week.