What is the treatment for acute portal vein thrombosis?

Treatment of Acute Portal Vein Thrombosis

Anticoagulation should be initiated immediately in all patients with acute portal vein thrombosis to prevent thrombus extension, mesenteric infarction, and achieve recanalization. 1

Initial Management Strategy

Immediate Anticoagulation Initiation

• Start therapeutic anticoagulation as soon as acute PVT is diagnosed, regardless of whether the patient has cirrhosis or not 1
• Early anticoagulation prevents thrombus extension in virtually all patients and prevents the catastrophic complication of mesenteric venous infarction 1, 2
• Delayed initiation of anticoagulation is associated with failure to achieve recanalization 1

Pre-Anticoagulation Assessment

Before starting anticoagulation, implement adequate prophylaxis for gastrointestinal bleeding, particularly variceal bleeding screening and management 1

• Evaluate for presence of esophageal varices via endoscopy 1
• Ensure varices are adequately treated with beta-blockers or band ligation before anticoagulation 1
• Assess platelet count and bleeding risk factors 1

Choice of Anticoagulant Agent

For Patients WITHOUT Cirrhosis

Use LMWH or fondaparinux as initial therapy 1

• LMWH is preferred over unfractionated heparin (UFH) due to lower risk of heparin-induced thrombocytopenia (which occurs in up to 20% of PVT patients on UFH) 1
• Fondaparinux is also preferred over IV or subcutaneous UFH 1
• Transition to vitamin K antagonist (VKA) targeting INR 2.0-3.0 after initial parenteral therapy 1

For Patients WITH Cirrhosis

The choice depends on Child-Pugh classification 1:

• Child-Pugh A or B: Use either DOAC or LMWH with/without VKA 1
• Child-Pugh C: Use LMWH alone (or as bridge to VKA only if baseline INR is normal) 1

The 2024 ISTH guidance endorses DOACs for Child-Pugh A and B cirrhosis, representing the most current evidence 1

Duration of Anticoagulation

Minimum Treatment Duration

Treat for at least 6 months in all patients with acute PVT 1

• Recanalization typically occurs within the first 6 months; no recanalization occurs beyond this timeframe 1, 2
• In the prospective multicenter study, recanalization of the portal vein occurred in 39% of anticoagulated patients after median 234 days 2

Extended/Lifelong Anticoagulation Indications

Continue anticoagulation beyond 6 months in the following scenarios 1:

• Liver transplant candidates: Continue until transplantation 1
• Superior mesenteric vein involvement with history of intestinal ischemia: Consider lifelong anticoagulation 1
• Underlying permanent prothrombotic conditions: Continue lifelong 1, 3
• Incomplete recanalization in transplant candidates: Prolong anticoagulation until transplant 1
• Progressive PVT despite anticoagulation in transplant candidates: Consider TIPS referral 1

Monitoring and Reassessment

Imaging Follow-up

• Assess thrombus extension with CT or MRI (not just ultrasound) 1
• Monitor for recanalization at regular intervals during the first 6 months 1, 2
• Recanalization rates: Portal vein 38-39%, mesenteric vein 61-73%, splenic vein 54-80% 2

Factors Associated with Recanalization Failure

Poor prognostic indicators for recanalization include 1, 2:

• Presence of ascites (hazard ratio 3.8) 2
• Occluded splenic vein (hazard ratio 3.5) 2
• Delayed anticoagulation initiation 1

Special Considerations

Thrombocytopenia in Cirrhosis

Do not withhold anticoagulation for moderate thrombocytopenia 1

• Full-dose anticoagulation is appropriate when platelets >50 × 10⁹/L 1
• When platelets are <50 × 10⁹/L, make individualized decisions based on thrombus extent, risk of extension, and bleeding risk 1
• Consider platelet support in the initial 30 days if needed 1

Symptomatic PVT with Bowel Ischemia

In patients not responding to anticoagulation or with contraindications, consider TIPS placement 1

• Catheter-directed thrombolysis may be considered but has not shown superior recanalization rates compared to anticoagulation alone 1
• Surgical evaluation is mandatory if bowel infarction is present 1

Safety Profile

Bleeding Risk

• Bleeding while on anticoagulation occurs in approximately 9-18% of patients 1, 4
• Mortality from anticoagulation-related bleeding is rare (2% in prospective studies) 1
• The risk of NOT anticoagulating (intestinal infarction, death) exceeds the bleeding risk 1, 2

Contraindications

Active bleeding is the primary contraindication 1

• Regularly reassess for contraindications if anticoagulation cannot be initiated 1
• Once bleeding is controlled, anticoagulation should be started 1