What is the recommended treatment for a non-occlusive thrombus in the portal vein?

Treatment of Non-Occlusive Portal Vein Thrombosis

Immediate anticoagulation with low molecular weight heparin (LMWH) is the recommended first-line treatment for non-occlusive portal vein thrombosis in the absence of major contraindications. 1

Initial Assessment and Treatment

• Diagnostic confirmation:

  • Doppler ultrasound as first-line investigation
  • Confirm with contrast-enhanced CT scan during portal phase to assess extension and signs of intestinal ischemia 1

• Initial anticoagulation:

  • Start LMWH immediately with target anti-Xa activity of 0.5-0.8 IU/ml 1
  • Monitor anti-Xa levels in patients with obesity, pregnancy, or renal dysfunction
  • Screen for heparin-induced thrombocytopenia (HIT), which occurs in up to 20% of PVT patients treated with unfractionated heparin 1

Treatment Based on Liver Function

For patients without cirrhosis or with compensated cirrhosis:

• Child-Pugh A or B cirrhosis:
  • Either DOAC (direct oral anticoagulant) or LMWH with/without VKA (vitamin K antagonist) based on patient preference 2
  • After initial LMWH, transition to oral vitamin K antagonists targeting INR 2-3 1

For patients with decompensated cirrhosis:

• Child-Pugh C cirrhosis:
  • LMWH alone (or as bridge to VKA in patients with normal baseline INR) 2
  • Avoid DOACs in these patients due to limited evidence

Special Considerations for Thrombocytopenia

• Anticoagulation should not be withheld in patients with moderate thrombocytopenia secondary to advanced liver disease 2
• 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

Duration of Treatment and Monitoring

• Minimum duration of anticoagulation therapy: 6 months 1
• Follow-up imaging with CT scan at 6-12 months to assess recanalization 1
• Regular reassessment of bleeding risk, ideally at 6-month intervals 1
• Monitor for signs of intestinal infarction (persistent severe abdominal pain, rectal bleeding, organ failure, massive ascites) 1

Treatment Efficacy and Considerations

• Early initiation of anticoagulation is associated with higher rates of portal vein recanalization 1
• Complete (57.5%) or partial (25.0%) recanalization can be achieved with anticoagulation 3
• Recanalization typically does not occur beyond 6 months of anticoagulation 1
• Discontinuation of anticoagulation may lead to PVT recurrence 4

Bleeding Risk Management

• Evaluate for varices and implement prophylaxis before initiating anticoagulation in cirrhotic patients 1
• Bleeding complications occur in approximately 9-18% of patients 1
• In a study of 40 cirrhotic patients with PVT on anticoagulation, 15 bleeding episodes (37.5%) occurred, with 73.3% requiring hospitalization and 53.3% requiring blood transfusion 3

Advanced Interventions for Refractory Cases

• For patients with high-grade non-occlusive or occlusive PVT not responding to anticoagulation:
  • Consider portal vein recanalization with transjugular intrahepatic portosystemic shunt (PVR-TIPS) 1, 5
  • Operative thrombectomy with intraoperative and postoperative thrombolysis may be considered in selected cases 6

Long-term Management

• Consider indefinite anticoagulation for:
  • Liver transplant candidates
  • Patients with history of intestinal ischemia
  • Patients with inherited thrombophilia 1
• Unrecanalised patients have a 55% risk of developing gastroesophageal varices during follow-up 1

Portal vein thrombosis requires prompt recognition and treatment to prevent potentially life-threatening complications such as intestinal infarction, which has a mortality rate of up to 60% if untreated 1.