Veno-occlusive disease of the liver after bone marrow transplantation: is hypercoagulability really part of the problem?

Patients undergoing bone marrow transplantation (BMT) experience changes in various proteins with important functions in the coagulation and fibrinolysis system. Veno-occlusive disease (VOD) of the liver is a leading cause of non-relapse mortality after BMT. Because of the concurrent occurrence of changes in the coagulation and fibrinolysis system and development of VOD, most authors assume a causative relationship between these two observations, but the results leading to this conclusion are not unequivocal. Data currently available do not allow the conclusion that coagulation activation and local excess fibrin generation are key factors in the pathogenesis of VOD. One approach to deciding whether there is, in fact, excessive local fibrin generation during the development of VOD might be the monitoring of high risk patients with tools that enable differentiation of local and systemic hypercoagulability (e.g. anti-D-dimer immunoscintigraphy). Screening of patients at risk for VOD with special coagulation parameters pretransplant does not seem appropriate at present. However, markedly increased plasminogen activator inhibitor-1 levels (from baseline) seem to be an appropriate tool to confirm the diagnosis of VOD when clinical suspicion exists. More research is needed in order to advance our understanding of the disease and to improve outcomes in both the prophylaxis and treatment of VOD.