What are the causes and symptoms of portal vein thrombosis (PVT)?

From the Guidelines

Portal vein thrombosis should be treated with immediate anticoagulation using low molecular weight heparin (LMWH) in the absence of major contraindications to anticoagulation. This approach is based on the most recent and highest quality evidence available, including the 2016 EASL clinical practice guidelines on vascular diseases of the liver 1. The guidelines recommend initiating anticoagulation with LMWH as the first line of treatment, with a target anti-Xa activity level between 0.5 and 0.8 IU/ml in overweight patients, pregnancy, and poor kidney function.

Key Considerations

• Anticoagulation therapy should be given for at least 6 months 1
• Patients should be evaluated for underlying causes, including cirrhosis, malignancy, inflammatory conditions, or hypercoagulable states
• Complications can include portal hypertension, variceal bleeding, and intestinal ischemia
• Regular monitoring with ultrasound or CT imaging is important to assess clot resolution
• Patients with cirrhosis require special consideration as anticoagulation carries higher bleeding risks

Special Considerations

• In patients with cirrhosis and portal vein thrombosis, urgent anticoagulation is required in cases of intestinal ischemia to minimize ischemic injury 1
• A multidisciplinary team approach, including gastroenterology and hepatology, interventional radiology, hematology, and surgery, is recommended for managing these complex cases
• Lifestyle modifications, such as avoiding dehydration and stopping oral contraceptives or hormone replacement therapy, may also be necessary

Monitoring and Follow-up

• A CT scan should be performed to assess recanalisation of the portal venous system at 6-12 months follow-up 1
• Patients with unrecanalised portal vein thrombosis should be screened for gastroesophageal varices 1
• MR imaging cholangiography may be necessary in patients with persisting cholestasis or biliary tract abnormalities suggestive of portal biliopathy 1

From the Research

Definition and Incidence of Portal Vein Thrombosis

• Portal vein thrombosis (PVT) is a rare disease with an estimated incidence of 2 to 4 cases per 100,000 inhabitants 2.
• PVT can be classified on the basis of the anatomical site, the degree of venous occlusion, and the timing and type of presentation 2.

Predisposing Conditions for Portal Vein Thrombosis

• The most common predisposing conditions for PVT are chronic liver diseases (cirrhosis), primary or secondary hepatobiliary malignancy, major infectious or inflammatory abdominal disease, or myeloproliferative disorders 2.
• More than half of PVT are provoked by liver cirrhosis, solid cancer or myeloproliferative neoplasms 3.

Management and Treatment of Portal Vein Thrombosis

• The management of PVT is based on anticoagulation and the treatment of predisposing conditions 2.
• Anticoagulant therapy in patients with acute symptomatic PVT should be started early after diagnosis, if no active bleeding, to obtain greater vessel recanalization and reduce the occurrence of portal-hypertension related complications 3.
• Different treatment options (unfractionated or low molecular weight heparin, vitamin K antagonists and direct oral anticoagulants [DOACs]) can be considered 3.
• The aim of anticoagulation in acute thrombosis is to prevent the extension of the clot and enable the recanalization of the vein to avoid the development of complications, such as intestinal infarction and portal hypertension 2.

Anticoagulation Therapy for Portal Vein Thrombosis

• The anticoagulant treatment is generally recommended for at least three to six months 2.
• Prosecution of anticoagulation is advised until recanalization or lifelong if the patient has an underlying permanent pro-coagulant condition that cannot be corrected or if there is thrombosis extending to the mesenteric veins 2.
• Anticoagulation is effective in preventing PVT progression and may achieve partial or complete PVT recanalization 4.
• Low-molecular-weight heparin and vitamin K antagonist have a similar safety profile without specific data in favor of any of them 4.

Interventional Treatment of Acute Portal Vein Thrombosis

• Interventional procedures have emerged as an alternative to surgery in symptomatic patients not responding to systemic anticoagulation 5.
• Different techniques for recanalization were employed, including catheter thromboaspiration, AngioJet device, local-lysis-only, and TIPSS 5.
• Interventional percutaneous approaches are able to improve patient outcome in patients with aPVT 5.