A novel risk-adjusted anticoagulation protocol, based on preoperatory risk factors as well as intraoperative and postoperative events, could decrease the risk of both thrombotic and hemorrhagic complications following pediatric liver transplant (PLT), according to a recently published study in Pediatric Blood and Cancer.

PLT can be the only therapeutic alternative for many diseases, including Alagille syndrome (ALGS), biliary atresia, and autoimmune hepatitis. Early thrombotic complications are the main cause of graft failure and retransplantation in the pediatric population. However, there is a great diversity among the anticoagulation protocols used by PLT programs, with no definite consensus on the appropriate agents or duration of therapy. 

The authors aimed to evaluate the performance of their risk-adjusted anticoagulation protocol through a retrospective review that included 69 patients and 73 transplants performed between 2014 and 2018 in the Children’s Hospital of Chicago in Illinois. 

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The median age of the included population was 2.3 years, with a median weight of approximately 13 kg (28.6 lb). Although biliary atresia was the most common indication for transplant, the study included patients with varied conditions, including ALGS, neoplasia, autoimmune hepatitis, and citrullinemia type 1. 

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According to protocol, only patients with an international normalized ratio (INR) lower than 1.5 received intraoperative unfractionated heparin (UFH). The standard dose was 100 units per kilogram. Platelet transfusions were only administered to patients with platelet counts below 20.000 or severe bleeding. Fresh frozen plasma was used in all patients weighing less than 10 kg.

All patients were initiated on a UFH drip after surgery. The low-risk group received a prophylactic dose of 10 units/kg/h, while the high-risk group received a therapeutic dose 2 to 3 times that dose based on the indication for anticoagulation. Criteria for anticoagulation included portal vein thrombosis (PVT) or hepatic artery thrombosis (HAT) during surgery, history of thrombosis, and history of HAT or PVT within 7 days previous to surgery, among others. 

More than 70% of patients received low dose anticoagulation, of which 6 were changed to a therapeutic dose due to postoperative vascular events. The most common causes of high-dose anticoagulation were intraoperative HAT and PVT.

The overall incidence of both PVT and HAT was approximately 5%. No patient in the low-dose group suffered from PVT, and HAT was more frequent in the high-dose group. There was no statistically significant difference in transfusion requirements between both groups. Nonetheless, the high-dose group required more surgical exploration for bleeding. 

All patients continued low-dose aspirin treatment for 6 months after surgery. After a 3-year follow-up, there was no significant difference in survival among groups. Yet, patients in the high-dose group were more likely to suffer from graft loss.

“The use of a standardized risk-adjusted anticoagulation protocol after PLT is associated with a low occurrence of thrombotic and hemorrhagic complications. High-dose anticoagulation leads to more bleeding, but those risks outweigh the risks of possible graft loss,” the authors wrote. 


Lemoine CP, Brandt KA, Mohammad S, et al. Early thrombotic and hemorrhagic complications associated with a risk‐adjusted postoperative anticoagulation protocol after pediatric liver transplantation. Pediatr Blood Cancer. Published online July 29, 2022. doi:10.1002/pbc.29898