What is the treatment for portal vein thrombosis?

Treatment of Portal Vein Thrombosis

Anticoagulation therapy is the cornerstone of treatment for portal vein thrombosis (PVT), with immediate initiation recommended for recent (<6 months) PVT that is >50% occlusive or involves the main portal vein or mesenteric vessels. 1

Diagnostic Approach

• First-line investigation: Doppler ultrasound
• Confirmatory test: Contrast-enhanced CT scan during portal phase (shows filling defects, mesenteric venous engorgement, fat-stranding, and edema) 1

Anticoagulation Decision Algorithm

When to Start Anticoagulation

• Immediate anticoagulation for:

  • Recent PVT (<6 months) that is >50% occlusive
  • Involvement of main portal vein or mesenteric vessels
  • Transplant candidates
  • Multiple vascular bed involvement
  • Evidence of thrombus progression
  • Inherited thrombophilia 1

• Observation with serial imaging for:

  • PVT with <50% occlusion
  • Isolated intrahepatic branch involvement 1

Choice of Anticoagulant Based on Liver Function

1. For Child-Pugh A or B cirrhosis:

   • Either Direct Oral Anticoagulants (DOACs) or Low Molecular Weight Heparin (LMWH) with/without Vitamin K Antagonists (VKAs) based on patient preference 2, 1

2. For Child-Pugh C cirrhosis:

   • LMWH alone (or as bridge to VKA in patients with normal baseline INR) 2, 1

3. For non-cirrhotic PVT:

   • LMWH (target anti-Xa activity 0.5-0.8 IU/ml in overweight patients, pregnancy, or poor kidney function)
   • VKAs (target INR 2-3) 1

Anticoagulation Duration

• Minimum: 6 months 1, 3
• Continue until:
  • Complete clot resolution in non-transplant candidates
  • Transplantation in transplant candidates
  • Lifelong in permanent hypercoagulable states or if thrombosis extends to mesenteric veins 1, 3

Monitoring Response

• Cross-sectional imaging every 3 months to assess recanalization 1
• Expected recanalization rates with anticoagulation:
  • Portal vein: 38-39%
  • Splenic vein: 54-80%
  • Superior mesenteric vein: 61-73% 1

Special Considerations

Thrombocytopenia

• Anticoagulation should not be withheld in patients with moderate thrombocytopenia secondary to advanced liver disease
• Case-by-case decision when platelet count is <50 × 10^9/L, based on:
  • Site and extent of thrombosis
  • Risk of thrombus extension
  • Patient preference
  • Presence of active bleeding/additional bleeding risk factors 2, 1

Variceal Bleeding

• Do not delay anticoagulation for variceal screening as this decreases recanalization rates 1
• For patients with recent variceal bleeding, endoscopic eradication of varices by band ligation should be performed before initiating anticoagulation 4, 5

Intestinal Ischemia

• Medical emergency requiring immediate inpatient care and urgent anticoagulation 1
• Consider interventional approaches (thrombectomy or thrombolysis) if no clinical improvement with anticoagulation 1

Benefits of Early Anticoagulation

• Early initiation (within 2 weeks) improves recanalization rates 1
• Improves survival (HR: 0.59; 95% CI: 0.49-0.70) 1
• Does not increase portal hypertensive bleeding risk 1, 6

Potential Complications

• Bleeding episodes may occur (37.5% in one study), but are generally non-severe and manageable 6
• Recurrence of PVT is common (70%) after anticoagulation withdrawal, supporting the need for extended therapy 6

Additional Interventions

• Consider Transjugular Intrahepatic Portosystemic Shunting (TIPS) for:
  • Patients with additional indications (refractory ascites, variceal bleeding)
  • Transplant candidates to facilitate technical feasibility 1

Key Pitfalls to Avoid

1. Delaying anticoagulation due to concerns about variceal bleeding
2. Premature discontinuation of anticoagulation (high recurrence risk)
3. Failing to monitor for recanalization with regular imaging
4. Withholding anticoagulation in patients with moderate thrombocytopenia