Venocclusive disease of the liver after bone marrow transplantation: The role of hemostasis

Venocclusive disease of the liver is a relatively frequent early complication of bone marrow transplantation related to pre-transplant toxic injury to the liver. Events that lead to toxicity of the liver in the pre-transplant setting are infection, anti-neoplastic and anti-infectious drug administration and radiation. The histological correlates of venocclusive disease are lesions mainly localized to structures in zone 3 of the liver acinus and in the sublobular central venules. At some point in the pathogenesis of venocclusive disease, blood clotting and inflammation occur. The first is characterized by laboratory signs of coagulation activation, by an increase in several procoagulant proteins and by a decrease in naturally occuring anticoagulants, particularly protein C, the latter being a sensitive index of liver injury. Inflammation is mediated by cytokine production, which maintains procoagulant endothelial responses and liver injury. Severe venocclusive disease is associated with multi-organ failure and elevated mortality. Attempts at finding predictive markers of the disease have succeeded in identifying some coagulation and inflammatory proteins which can be useful in predicting the occurrence of VOD in selected patient groups. The role of hemostasis in venocclusive disease is under-scored also by the reports on the successful prophylaxis and management of the disease with heparin and thrombolytic agents.