A rare case of Gynura-segetum-related hepatic sinus obstruction syndrome complicated with alcoholic liver disease.

Hepatic sinus obstruction syndrome (HSOS) is easy to be misdiagnosed or missed, and there is no unified and effective treatment for it. A patient was considered to have Budd-Chiari syndrome. He underwent a transjugular liver biopsy, and pathological examination revealed HSOS without liver cirrhosis. After the failure of anticoagulation therapy, he successfully received a transjugular intrahepatic portosystemic shunt (TIPS). After discharge, he was followed-up for four years with a good prognosis. G. segetum-induced HSOS can be easily overlooked, especially in patients with underlying liver diseases. When medical therapy fails, TIPS can control ascites and portal hypertension, and the long-term prognosis is optimistic.

[Porto sinusoidal vascular disease: an unusual cause of digestive bleeding]. / Enfermedad vascular porto sinusoidal: una causa inusual de sangrado digestivo.

Portal hypertension (PHT) is defined as an increase in pressure at the level of the portal vein above 5 mmHg, the most common cause being liver cirrhosis. Among the presinusoidal intrahepatic causes of PHT with portal venular involvement, what was traditionally known as idiopathic non-cirrhotic portal hypertension (NCIH) is described, with the requirements of excluding those patients who did not present PHT, as well as those with the presence of liver cirrhosis and thrombosis. portal venous vein (PVT). Currently, the diagnostic criteria for this entity have been reconsidered, and its name, being known as porto-sinusoidal vascular disease (PSVD), also does not exclude patients with PHT or the presence of underlying liver disease. Liver biopsy continues to be the gold standard for diagnosis. The clinical manifestations are derived from PHT and the management is similar to the complications that occur in patients with liver cirrhosis. The case of a male patient is presented who presents with symptoms of digestive bleeding, with findings of esophageal varices in upper endoscopy in addition to a study of viral, autoimmune liver disease and negative deposits, with a conclusive liver biopsy of porto-sinusoidal vascular disease.

Primary Budd-Chiari syndrome versus sinusoidal obstruction syndrome: a review.

Budd-Chiari syndrome (BCS) and sinusoidal obstruction syndrome (SOS) are two major vascular disorders of the liver, of which both can cause portal hypertension related complications, but their locations of obstruction are different. BCS refers to the obstruction from the hepatic vein to the junction between the inferior vena cava and right atrium, which is the major etiology of post-sinusoidal portal hypertension; by comparison, SOS is characterized as the obstruction at the level of hepatic sinusoids and terminal venulae, which is a cause of sinusoidal portal hypertension. Both of them can cause hepatic congestion with life-threatening complications, especially acute liver failure and chronic portal hypertension, and share some similar features in terms of imaging and clinical presentations, but they have heterogeneous risk factors, management strategy, and prognosis. Herein, this paper reviews the current evidence and then summarizes the difference between primary BCS and SOS in terms of risk factors, clinical features, diagnosis, and treatment.

Transjugular intrahepatic portosystemic shunt for pyrrolidine alkaloids-induced hepatic sinusoidal obstruction syndrome: a retrospective cohort study.

BACKGROUND: This study aimed to investigate the efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) in the treatment of patients with pyrrolidine alkaloids-induced hepatic sinusoidal obstruction syndrome (PA-HSOS). METHODS: Patients diagnosed with PA-HSOS and treated in Ningbo No.2 Hospital between November 2017 and October 2022 were enlisted in this retrospective cohort study. RESULTS: This cohort comprised a total of 22 patients with PA-HSOS, of which 12 patients received TIPS treatment and 10 patients experienced conservative treatment. The median follow-up duration was 10.5 months. Baseline characteristics existed with no significant difference between the two groups. No operation failures or any TIPS-associated intraoperative complications were observed after TIPS. In the TIPS group, the portal venous pressure was substantially decreased from 25.3 ±â€…6.3 mmHg to 14.4 ±â€…3.5 mmHg after TIPS ( P  = 0.002). Compared with preoperative, the ascites after TIPS were significantly subsided ( P  = 0.001) and there existed a considerable decrease in Child-Pugh score. At the end of follow-up, 5 patients died, involving 1 in the TIPS group and 4 in the conservative treatment group. The median survival time was 13 (3-28) months in the TIPS group and 6.5 (1-49) months in the conservative treatment group, respectively. The survival analysis demonstrated that the total survival time of TIPS group was longer than that of the conservative treatment group, no statistical significance was observed ( P  = 0.08). CONCLUSION: TIPS may be a secure and effective therapeutic strategy for PA-HSOS patients who do not respond to conservative treatment.

Point shear-wave elastography for the diagnosis of veno-occlusive disease in children and young adults.

BACKGROUND: Hepatic veno-occlusive disease or sinusoidal obstruction syndrome is a potentially life-threatening complication of hematopoietic stem cell transplantation. OBJECTIVE: To assess the usefulness of point shear-wave elastography (pSWE) for the early diagnosis of sinusoidal obstruction syndrome (SOS) in children. MATERIALS AND METHODS: A retrospective study was carried out in 43 patients with suspected SOS assessed between March 2018 and November 2021. Diagnosis of SOS was confirmed in 28 patients based on the European Society for Blood and Marrow Transplantation diagnostic criteria. Abdominal ultrasound and pSWE of the liver were performed before and after hematopoietic stem cell transplantation on first suspicion of SOS. RESULTS: Liver stiffness on initial suspicion was higher in patients diagnosed with SOS and these values increased compared to the pre-transplantation values. A cutoff value of 1.37 m/s was found for the diagnosis of SOS, with an area under the curve of 0.779 (95% CI 0.61-0.93). CONCLUSION: Point shear wave elastography of the liver is a promising technique for the early diagnosis of pediatric SOS.

Endothelial dysfunction and vascular complications after allogeneic hematopoietic cell transplantation: an expert analysis.

INTRODUCTION: Allogeneic hematopoietic cell transplantation (alloHCT) is the standard of care for many diseases. However, survivors often present with serious complications resulting from acute and chronic toxicities and it is crucial to increase consciousness from treating physicians. AREAS COVERED: We performed a comprehensive review of the literature and critically examined recent available data, mostly using the PubMed and Medline search engines for original articles published over the last decade. Better understanding of many alloHCT-related disorders has shown that endothelial injury and vascular damage plays a critical role. EXPERT OPINION: The most widely studied endothelial injury syndromes (EIS) are veno-occlusive disease/sinusoidal obstruction syndrome (SOS/VOD), graft-versus-host-disease (GVHD), and transplant-associated thrombotic microangiopathy (TA-TMA). TA-TMA, frequently underdiagnosed, needs to be clarified using certain criteria and, as a life-threatening condition, requires immediate and intensive treatment. The first-in-class complement inhibitor eculizumab has significantly improved outcomes in both the pediatric and adult population. Cardiovascular (CV) events are the second major cause of morbidity and mortality of alloHCT survivors, after GVHD. Long-term monitoring and management of CV risk is expected to also incorporate patient stratification with CV risk prediction models, early markers of vascular dysfunction or procoagulant activity, subclinical target organ damage, arterial stiffness, and subclinical atherosclerosis.

Sinusoidal Obstruction Syndrome Promotes Liver Metastatic Seeding of Colorectal Cancer Cells in a Rat Model.

BACKGROUND/AIM: Sinusoidal obstruction syndrome (SOS) after neoadjuvant chemotherapy with oxaliplatin for colorectal liver metastases (CRLM) has been reported to lead to early recurrence. This study investigated the effects of SOS on the development of CRLM in a rat model. MATERIALS AND METHODS: RCN-H4 cells were injected into the spleen or liver of ten monocrotaline-treated (SOS group) and ten untreated (control group) rats. The number and size of liver tumors were compared between the groups. RESULTS: The number of liver tumors in the splenic RCN-H4 injection model was significantly higher in the SOS group than in the control group (332±213 vs. 16±5, p=0.029); however, the largest tumor diameter in the hepatic model was similar between groups (6.2±1.8 vs. 6.4±2.4 mm, p=0.87). CONCLUSION: SOS promotes CRLM development by splenic RCN-H4 cell injection. This might be due to the higher incidence of cancer cell implantation into the liver.

Liver Stiffness by Transient Elastography to Detect Porto-Sinusoidal Vascular Liver Disease With Portal Hypertension.

BACKGROUND AND AIMS: Porto-sinusoidal vascular liver disease (PSVD) is a rare cause of portal hypertension. PSVD is still often misdiagnosed as cirrhosis, emphasizing the need to improve PSVD diagnosis strategies. Data on liver stiffness measurement using transient elastography (TE-LSM) in PSVD are limited. The aim of this study was to evaluate the accuracy of TE-LSM to discriminate PSVD from cirrhosis in patients with signs of portal hypertension. APPROACH AND RESULTS: Retrospective multicenter study comparing TE-LSM in patients with PSVD, according to Vascular Liver Disease Interest Group criteria, with patients with compensated biopsy-proven cirrhosis associated with alcohol (n = 117), HCV infection (n = 110), or NAFLD (n = 46). All patients had at least one sign of portal hypertension among gastroesophageal varices, splenomegaly, portosystemic collaterals, history of ascites, or platelet count < 150 × 109 /L. The 77 patients with PSVD included in the test cohort had lower median TE-LSM (7.9 kPa) than the patients with alcohol-associated, HCV-related, and NAFLD-related cirrhosis (33.8, 18.2, and 33.6 kPa, respectively; P < 0.001). When compared with cirrhosis, a cutoff value of 10 kPa had a specificity of 97% for the diagnosis of PSVD with a 85% positive predictive value. A cutoff value of 20 kPa had a sensitivity of 94% for ruling out PSVD with a 97% negative predictive value. Of the patients, 94% were well-classified. Even better results were obtained in a validation cohort including 78 patients with PSVD. CONCLUSIONS: This study including a total of 155 patients with PSVD and 273 patients with cirrhosis demonstrates that TE-LSM < 10 kPa strongly suggests PSVD in patients with signs of portal hypertension. Conversely, when TE-LSM is >20 kPa, PSVD is highly unlikely.

A Meta-Analysis Evaluating the Incidence of Bleeding Events With Intravenous Defibrotide Treatment Outside the Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome Setting.

Defibrotide is approved to treat hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) with renal/pulmonary dysfunction following hematopoietic cell transplantation (HCT) in adult and pediatric patients in the United States, and to treat severe hepatic VOD/SOS post HCT in adult and pediatric patients aged >1 month in the European Union. The defibrotide prescribing information warns that defibrotide may increase bleeding risk in VOD/SOS patients. To broaden our understanding of the incidence of bleeding with defibrotide, we performed a meta-analysis of the published literature of defibrotide use outside of the post-HCT VOD/SOS setting. Of 1857 records identified, 125 reported on defibrotide; 23 contained data on bleeding events. The estimated overall incidence of bleeding events was 1% (95% confidence interval [CI]: 0%-2%) and 8% (95% CI: 3%-14%) in studies using intravenous defibrotide and studies with controls, respectively. The risk ratio for bleeding events with intravenous defibrotide versus controls was 0.36 (95% CI: 0.24-0.52; P < .00001) among studies with data on intravenous defibrotide and controls. This meta-analysis of defibrotide use outside of the post-HCT VOD/SOS setting suggests that the incidence of bleeding with defibrotide is lower than controls.

NRF2 activates growth factor genes and downstream AKT signaling to induce mouse and human hepatomegaly.

BACKGROUND & AIMS: Hepatomegaly can be triggered by insulin and insulin-unrelated etiologies. Insulin acts via AKT, but how other challenges cause hepatomegaly is unknown. METHODS: Since many hepatomegaly-inducing toxicants and stressors activate NRF2, we examined the effect of NRF2 activation on liver size and metabolism using a conditional allele encoding a constitutively active NRF2 variant to generate Nrf2Act-hep mice in which NRF2 is selectively activated in hepatocytes. We also used adenoviruses encoding variants of the autophagy adaptor p62/SQSTM1, which activates liver NRF2, as well as liver-specific ATG7-deficient mice (Atg7Δhep) and liver specimens from patients with hepatic sinusoidal obstruction syndrome (HSOS) and autoimmune hepatitis (AIH). RNA sequencing and cell signaling analyses were used to determine cellular consequences of NRF2 activation and diverse histological analyses were used to study effects of the different manipulations on liver and systemic pathophysiology. RESULTS: Hepatocyte-specific NRF2 activation, due to p62 accumulation or inhibition of KEAP1 binding, led to hepatomegaly associated with enhanced glycogenosis, steatosis and G2/M cell cycle arrest, fostering hyperplasia without cell division. Surprisingly, all manipulations that led to NRF2 activation also activated AKT, whose inhibition blocked NRF2-induced hepatomegaly and glycogenosis, but not NRF2-dependent antioxidant gene induction. AKT activation was linked to NRF2-mediated transcriptional induction of PDGF and EGF receptor ligands that signaled through their cognate receptors in an autocrine manner. Insulin and insulin-like growth factors were not involved. The NRF2-AKT signaling axis was also activated in human HSOS- and AIH-related hepatomegaly. CONCLUSIONS: NRF2, a transcription factor readily activated by xenobiotics, oxidative stress and autophagy disruptors, may be a common mediator of hepatomegaly; its effects on hepatic metabolism can be reversed by AKT/tyrosine kinase inhibitors. LAY SUMMARY: Hepatomegaly can be triggered by numerous etiological factors, including infections, liver cancer, metabolic disturbances, toxicant exposure, as well as alcohol abuse or drug-induced hepatitis. This study identified the oxidative stress response transcription factor NRF2 as a common mediator of hepatomegaly. NRF2 activation results in elevated expression of several growth factors. These growth factors are made by hepatocytes and activate their receptors in an autocrine fashion to stimulate the accumulation of glycogen and lipids that lead to hepatocyte and liver enlargement. The protein kinase AKT plays a key role in this process and its inhibition leads to reversal of hepatomegaly.

Ocular hemorrhage secondary to thioguanine-associated veno-occlusive disease in a child with acute lymphoblastic leukemia in delayed intensification.

Hepatic VOD is a potentially fatal complication during stem cell transplantation and is rarely seen in the non-transplant setting. We report the case of a five-year-old boy who presented with visual complaints during delayed intensification phase of treatment for ALL. He was found to have bilateral retinal hemorrhages associated with profound thrombocytopenia due to chemotherapy. VOD was diagnosed based on EBMT criteria and was managed with supportive care. Despite resolution of VOD, his vision progressively deteriorated and resulted in blindness. This case highlights the significance of close monitoring of ALL patients in delayed intensification when they are at risk for developing VOD, the importance of refractory thrombocytopenia as a diagnostic feature and the potential for VOD to manifest with intraocular bleeding.

Analysis of glutathione S-transferase and cytochrome P450 gene polymorphism in recipients of dose-adjusted busulfan-cyclophosphamide conditioning.

Sporadic incidence of veno-occlusive disease (VOD) continues to occur, despite achievement of recommended busulfan (BU) concentrations after real-time BU dose adjustment. To explore the potential influence of glutathione S-transferase (GST) and cytochrome P450 (CYP) genotypes on plasma BU concentration, subsequent VOD, and transplant outcome, we assessed the polymorphisms of multiple GST and CYP genes. Fifty-five patients were included (median age 38 years; range 21-67). Of these, 49 received dose-adjusted BU/CY therapy. Twenty-six patients received transplants from human leukocyte antigen-identical siblings, 26 from unrelated donors. The GSTA1*A/*A genotype was significantly associated with lower BU first-dose area under curve (AUC1st). We found that patients with higher AUC1st showed a significantly higher serum total bilirubin during the first month after transplantation, but this was not necessarily associated with subsequent development of VOD. We further analyzed a possible association of GST and CYP polymorphisms and VOD development, and found none of the polymorphisms investigated was associated with VOD incidence. Regarding transplant outcomes, GSTM1-positive patients showed lower relapse rates and better overall survival in multivariate analyses. These results suggest that a GSTM1-positive genotype in patients receiving BU/CY conditioning protects against relapse of hematological malignancies after allogeneic hematopoietic stem cell transplantation.

Portal Hypertension: Pathogenesis and Diagnosis.

Portal hypertension (PH) is an increase in the pressure gradient between portal vein and inferior vena cava. Increased resistance occurs at different levels within the portal venous system, followed by increased portal venous inflow. PH is the main driver of cirrhosis decompensation. Varices on endoscopy or portosystemic collaterals on imaging indicate PH. Although its cause is determined mostly via noninvasive tests, the gold standard to measure portal pressure in cirrhosis and determine its severity is hepatic vein catheterization with determination of the hepatic venous pressure gradient. Measuring portal pressure is essential in proof-of-concept studies of portal pressure-lowering drugs.

Biomarkers for Early Complications After Hematopoietic Stem Cell Transplantation.

Advances in the field of omics have led to a significant expansion in biomarkers identified for complications after hematopoietic stem cell transplantation (HSCT). Biomarkers can offer an effective method for early identification of a specific disease and can be used to guide therapies. Ongoing investigations to discover biomarkers for acute graft-versus-host disease as well as other post-HSCT complications may improve early diagnosis, prognosis, and the development of new therapeutic targets. The authors review the most recent and validated diagnostic, prognostic, predictive, and response to treatment biomarkers for early complications following HSCT consistent with 2014 NIH consensus on biomarker criteria.

Risk factors for hepatic veno-occlusive disease caused by Gynura segetum: a retrospective study.

BACKGROUND: Hepatic veno-occlusive disease (HVOD) caused by Gynura segetum has been increasingly reported in China in recent years. The aim of this retrospective study was to identify independent prognostic markers for survival in patients with Gynura segetum-induced HVOD and to evaluate the effect of anticoagulants and transjugular intrahepatic portosystemic shunt (TIPS) on survival rate. METHODS: Clinical data including symptoms, signs, imaging characteristics, laboratory test results, results of liver tissue biopsies, type of treatment during follow-up and clinical outcomes were collected. Univariate, multivariate and time-dependent Cox regression analyses were performed. RESULTS: Survival rates were 91% (95% confidence interval [CI], 82-95%), 64% (95% CI, 53-69%) and 57% (95% CI, 51-65%) at 1, 3 and 60 months, respectively. Total bilirubin, albumin and hepatic encephalopathy were independent prognostic markers of survival. Anticoagulants were administered to 76% of the patients. Among 75 patients treated with anticoagulants, 49 patients (65.3%) were cured, whereas 26 patients (34.7%) died; the cure rate in anticoagulant-treated patients was higher than that of those not treated with anticoagulants (χ2 = 9.129, P = 0.004). Cure rate of the anticoagulation + TIPS treatment group was 64.3%, which was also higher than that of the non-anticoagulation group; however, this was not significantly different (χ2 = 3.938, P = 0.096). CONCLUSIONS: The presence of hepatic encephalopathy, serum bilirubin and albumin levels were major prognostic factors for Gynura segetum-induced HVOD. Anticoagulation therapy significantly increased the cure rate; however, TIPS treatment did not have a beneficial effect on the cure rate.

Fulminant hepatitis due to very severe sinusoidal obstruction syndrome (SOS/VOD) after autologous peripheral stem cell transplantation: a case report.

BACKGROUND: Hepatic veno-occlusive disease, also called sinusoidal obstruction syndrome (SOS/VOD), is a potentially fatal complication of allogeneic or autologous hematopoietic stem cell transplantation. A plethora of transplant and patient-related risk factors predispose to SOS/VOD and should be taken into account for prognosis assessment as well as for adequate therapeutic intervention. CASE PRESENTATION: We describe the case of a mantle cell lymphoma patient who developed a fulminant hepatitis following oxaliplatin-containing intensive chemotherapy and autologous transplantation. This clinical manifestation was secondary to a very severe SOS/VOD. The patient did not exhibit the usual risk factors and presented a non-classical form with major cytolysis, thus puzzling SOS/VOD diagnosis in this context. CONCLUSION: SOS has been previously reported after oxaliplatin-based chemotherapy regimens for colorectal cancers, in particular in patients with colorectal liver metastases. We therefore suspected a potential relationship with oxaliplatin-based regimen as a driver of SOS/VOD in a non-susceptible lymphoma patient. With regards to this case, clinicians and especially intensivists should be aware of this atypical presentation.

Biology of portal hypertension.

Portal hypertension develops as a result of increased intrahepatic vascular resistance often caused by chronic liver disease that leads to structural distortion by fibrosis, microvascular thrombosis, dysfunction of liver sinusoidal endothelial cells (LSECs), and hepatic stellate cell (HSC) activation. While the basic mechanisms of LSEC and HSC dysregulation have been extensively studied, the role of microvascular thrombosis and platelet function in the pathogenesis of portal hypertension remains to be clearly characterized. As a secondary event, portal hypertension results in splanchnic and systemic arterial vasodilation, leading to the development of a hyperdynamic circulatory syndrome and subsequently to clinically devastating complications including gastroesophageal varices and variceal hemorrhage, hepatic encephalopathy from the formation of portosystemic shunts, ascites, and renal failure due to the hepatorenal syndrome. This review article discusses: (1) mechanisms of sinusoidal portal hypertension, focusing on HSC and LSEC biology, pathological angiogenesis, and the role of microvascular thrombosis and platelets, (2) the mesenteric vasculature in portal hypertension, and (3) future directions for vascular biology research in portal hypertension.

Burden of illness associated with sinusoidal obstruction syndrome/veno-occlusive disease in patients with hematopoietic stem cell transplantation.

AIMS: Sinusoidal obstruction syndrome (SOS) is a life-threatening complication of hematopoietic stem cell transplantation (HSCT) associated with significant morbidity and mortality. Healthcare utilization, costs, and mortality were assessed in HSCT patients diagnosed with SOS, with and without multi-organ dysfunction (MOD). MATERIALS AND METHODS: This retrospective observational study identified real-world patients undergoing HSCT between January 1, 2009 and May 31, 2014 using the Premier Healthcare Database. In absence of a formal ICD-9-CM diagnostic code, SOS patients were identified using a pre-specified definition adapted from Baltimore and Seattle criteria and clinical practice. Severe SOS (SOS/MOD) and non-severe SOS (SOS/no-MOD) were classified according to clinical evidence for MOD in the database. RESULTS: Of the 5,418 patients with a discharge diagnosis of HSCT, 291 had SOS, with 134 categorized as SOS/MOD and 157 as SOS/no-MOD. The remaining 5,127 patients had HSCT without SOS. Overall SOS incidence was 5.4%, with 46% having evidence of MOD. Distribution of age, gender, and race were similar between the SOS cohorts and non-SOS patients. After controlling for hospital profile and admission characteristics, demographics, and clinical characteristics, the adjusted mean LOS was 31.0 days in SOS/MOD compared to 23.9 days in the non-SOS cohort (medians = 26.9 days vs 20.8 days, p < .001). The adjusted mean cost of SOS/MOD patients was $140,653, which was $41,702 higher than the non-SOS cohort (medians = $105,749 vs $74,395, p < .001). An almost 6-fold increased odds of inpatient mortality was associated with SOS/MOD compared to the non-SOS cohort (odds ratio = 5.88; 95% CI = 3.45-10.33). LIMITATIONS: Limitations of retrospective observational studies apply, since the study was not randomized. Definition for SOS was based on ICD-9 diagnosis codes from a hospital administrative database and reliant on completeness and accuracy of coding. CONCLUSIONS: Analysis of real-world data shows that SOS/MOD is associated with significant increases in healthcare utilization, costs, and inpatient mortality.

Defibrotide for Patients with Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome: Interim Results from a Treatment IND Study.

Hepatic veno-occlusive disease, or sinusoidal obstruction syndrome (VOD/SOS), is a serious and potentially fatal complication of conditioning for hematopoietic stem cell transplantation (HSCT) or of chemotherapy regimens alone. Defibrotide is a complex mixture of single-stranded polydeoxyribonucleotides that is approved in the United States for treating hepatic VOD/SOS with renal or pulmonary dysfunction post-HSCT and in the European Union, Israel, and South Korea for treating severe hepatic VOD/SOS post-HSCT. Defibrotide was previously available in the United States as an investigational drug through a treatment protocol (treatment IND) study. Interim results of that large, treatment IND study of patients with VOD/SOS and with or without multiorgan dysfunction (MOD; also known as multiorgan failure) are presented here. Defibrotide was administered i.v. at 6.25 mg/kg every 6 hours (25 mg/kg/day), with a recommended treatment duration of at least 21 days. Enrolled patients (n = 681) were diagnosed with VOD/SOS based on Baltimore or modified Seattle criteria or liver biopsy analysis. Among the 573 HSCT recipients, 288 (50.3%; 95% confidence interval [CI], 46.2% to 54.4%) were alive at day +100 post-HSCT. Day +100 survival for the pediatric (≤16 years) and adult (>16 years) subgroups was 54.5% (95% CI, 49.1% to 60.0%; n = 174 of 319) and 44.9% (95% CI, 38.8% to 51.0%; n = 114 of 254), respectively. In the MOD subgroup, 159 of 351 patients (45.3%; 95% CI, 40.1% to 50.5%) of patients were alive at day +100 post-HSCT. Treatment with defibrotide was generally well tolerated, and drug-related toxicities were consistent with previous studies. Adverse events were reported in 69.6% of safety-evaluable patients (399 of 573). Other than VOD/SOS and associated MOD symptoms, the most commonly reported treatment-emergent adverse event was hypotension (13.8%). Day +100 survival results observed in this trial were consistent with results seen in previous trials of defibrotide for VOD/SOS in adult and pediatric patients. These data support the potential benefit of defibrotide in treating a VOD/SOS patient population that includes those with and without MOD.