OBJECTIVETo evaluate the morbidity, risk factors, clinical characterisitics, treatments and prognosis of delayed hepatic veno-occlusive disease(HVOD) after haploidentical hematopoietic stem cell transplantation (hi-HSCT).

METHODSThe clinical data of 208 patients undergoing hi-HSCT were retrospectively analyzed.

RESULTSSix patients were diagnosed with delayed VOD, among them 4 patients were moderate VOD and 2 patients were severe VOD. The incidence of VOD after hi-HSCT was 2.88%, the median onset time was 44.5(30-57) days after transplant, 2 patients died of multiple organ failure (MOF) due to rapid progress of disease. With intravenous administration of defibrotide, 4 patients displayed encouraging response, but 2 patients died of hepatic acute graft-versus-host disease (aGVHD), 1 had bone marrow relapse and the other one was cured.

CONCLUSIONNorethindrone is one of the high risk factors, while sex, age and disease status are irrelevant to the occurrence of VOD. Unfractionated heparin (UH) can effectively decrease the morbidity. Pretransplant hepatic function reserve, high dose preconditioning regimens and pharmacotherapy may result in delayed VOD onset. The delayed VOD has the same clinical features and treatment-response as early VOD, but a poorer prognosis is usually observed. A larger amount of samples (patients) is needed to research the relationship of the delayed VOD with hi-HSCT. Defibrotide can effectively increase the survival rate of VOD patients.