Sinusoidal Obstruction Syndrome (Veno-occlusive Disease) Following Hematopoietic Stem Cell Transplant: Insights and Therapeutic Advances.

Hepatic sinusoidal obstruction syndrome (SOS) is a rare fatal clinical entity seen following hematopoietic stem cell transplant (HSCT). It is more commonly reported to occur following allogeneic HSCT compared to autologous HSCT. Historically, it is known as hepatitis following HSCT. It is thought that endothelial damage to the hepatic venules leading to occlusion of the terminal hepatic venules and hepatic sinusoids is the trigger for the development of SOS. Several risk factors have been associated with this condition. Some of these risk factors are patient related while others are transplant process related. Given the high mortality of this condition, early identification of high-risk patients with severe disease is of utmost importance. The management of SOS varies depending on the severity of the disease. Mild to moderate disease has a good outcome with supportive measures alone, while severe presentation of the disease requires a more aggressive management. Defibrotide is the only Food and Drug Administration-approved therapy and it is reserved for severe cases of SOS. The role of defibrotide as a prophylactic therapy remains under investigation.