How should veno‑occlusive disease (VOD) be managed?

Management of Veno-Occlusive Disease (VOD)

VOD management relies primarily on supportive care with defibrotide as the only approved specific therapy for severe cases, requiring early diagnosis and prompt treatment initiation within 2 days of diagnosis to reduce mortality. 1, 2, 3

Diagnostic Confirmation

Before initiating treatment, confirm VOD diagnosis using clinical criteria combined with objective measures:

• Apply EBMT 2023 diagnostic criteria for early detection 2, 4
• Measure hepatic venous pressure gradient via transjugular approach (>10 mmHg has 91% specificity and 85% positive predictive value) 1
• Obtain transjugular liver biopsy when feasible, as findings influence treatment decisions in ~90% of patients 1
• Use Doppler ultrasound to assess portal flow reversal and monophasic hepatic vein flow, though sensitivity is limited 1
• Monitor bilirubin (sensitive but not specific), platelet count, and liver enzymes 1

Critical pitfall: Percutaneous biopsy is often contraindicated due to thrombocytopenia and coagulopathy—use transjugular approach instead 1.

Treatment Algorithm by Severity

Mild to Moderate VOD

• Supportive care alone is the primary approach 1
• Manage fluid retention aggressively
• Treat sepsis promptly
• Support organ function as needed
• Monitor closely for progression to severe disease

Severe VOD (with hyperbilirubinemia, weight gain >5%, hepatomegaly, ascites)

Initiate defibrotide immediately 1, 3, 5:

• Dose: 6.25 mg/kg IV every 6 hours (25 mg/kg/day total)
• Start on day of diagnosis—71% of successful cases began same-day treatment 3
• Continue for minimum 21 days or until VOD resolution
• Do not interrupt dosing—minimizing interruptions is key to successful outcomes 3

Supportive measures:

• Diuretics for fluid management
• Avoid hepatotoxic medications
• Maintain platelet count >30,000/μL if possible
• Monitor for multiorgan failure

Very Severe VOD (with multiorgan failure)

In addition to defibrotide 3, 5:

• Consider TIPS (transjugular intrahepatic portosystemic shunt) as rescue therapy if expertise available 1
• Molecular adsorbent recirculating system (MARS) for acute liver failure 6
• Liver transplantation only as last resort in select cases with intractable disease 1

Important caveat: Surgical shunting and transplantation have limited data and should only be considered when defibrotide fails and expertise is immediately available 1.

Prevention Strategies

For High-Risk Patients (pre-HSCT, post-inotuzumab ozogamicin)

Defibrotide prophylaxis is justified in pediatric high-risk patients despite EMA DHPC 7:

• Reduces VOD risk by 70% (risk ratio 0.30) 7
• Particularly critical for infants and children with multiple risk factors
• Use weighted scoring system to identify candidates 7

For patients receiving inotuzumab ozogamicin before transplant 8, 9:

• Limit to maximum 2 cycles before HSCT
• Monitor bilirubin strictly before conditioning
• Avoid conditioning regimens with two alkylating agents or busulfan
• Use VOD prophylaxis with ursodeoxycholic acid or defibrotide
• Age ≥55 years increases risk significantly

Risk Reduction Measures

• Reduce intensity of myeloablative regimens when possible 1
• Avoid hepatotoxic drugs during high-risk periods
• Screen for pre-existing liver disease (portal hypertension, cirrhosis) 8

Monitoring During Treatment

Weekly imaging even without clinical suspicion of VOD 10:

• Doppler ultrasound for hepatic flow patterns
• Assess for ascites, hepatomegaly, splenomegaly

Laboratory monitoring:

• Daily bilirubin, transaminases, coagulation studies
• Platelet counts
• Renal function

Clinical assessment:

• Daily weights
• Abdominal girth measurements
• Signs of fluid overload or organ dysfunction

Adverse Event Management with Defibrotide

Hemorrhagic complications occur but are generally mild 3:

• Hematuria (43% of patients)
• Epistaxis (18%)
• Hypotension (11%)
• Severe hemorrhage rare (7%), typically with progressive VOD

Management approach:

• Continue defibrotide unless life-threatening bleeding
• Transfuse platelets to maintain >30,000/μL
• Manage hypotension with fluids; vasopressors if needed
• Severe bleeding requires multidisciplinary assessment of risk-benefit

Outcomes and Prognosis

With early defibrotide treatment 3:

• Complete VOD resolution: 75%
• Day 100 survival: 64% overall
• Day 100 survival with very severe VOD: 53%

Key success factors 2, 3:

• Early diagnosis (within 2 days of symptom onset)
• Prompt defibrotide initiation
• Minimizing treatment interruptions
• Multidisciplinary team involvement (hematologists, hepatologists, radiologists)

The evidence strongly supports that delayed diagnosis and treatment initiation are the primary modifiable factors associated with poor outcomes 2, 3, 5.