What are the implications of portal vein thrombosis (PVT)?

From the Guidelines

Portal vein thrombosis (PVT) should be treated with anticoagulation therapy, with low molecular weight heparin (LMWH) as the initial treatment, followed by oral anticoagulants, such as warfarin or direct oral anticoagulants (DOACs), for at least 6 months, as recommended by the most recent guidelines 1. The treatment approach for PVT involves several key considerations, including the use of anticoagulation therapy to prevent thrombus extension and bowel ischemia, as well as the evaluation of underlying causes such as cirrhosis, malignancy, inflammatory conditions, or hypercoagulable states. Some of the key points to consider in the management of PVT include:

• The use of LMWH as the initial treatment, with a dose of 1 mg/kg twice daily, followed by oral anticoagulants, such as warfarin, with a target INR of 2-3, or DOACs, such as rivaroxaban, 15-20 mg daily 1.
• The duration of treatment, which depends on whether the thrombosis is provoked (3-6 months) or unprovoked (often indefinite) 1.
• The consideration of thrombolysis in select cases of acute PVT, particularly in patients with severe symptoms or those who are at high risk of complications 1.
• The evaluation of underlying causes, including cirrhosis, malignancy, inflammatory conditions, or hypercoagulable states, and the management of these conditions to reduce the risk of recurrent thrombosis 1.
• The monitoring of patients for complications, such as portal hypertension, variceal bleeding, and intestinal ischemia, and the management of these complications with therapies such as beta-blockers, endoscopic variceal ligation, and surgical intervention, as needed 1.
• The consideration of long-term anticoagulation in patients with unprovoked PVT, or those with a history of recurrent thrombosis, as well as the use of anti-Xa activity monitoring in patients with overweight, pregnancy, or poor kidney function, targeting a level between 0.5 and 0.8 IU/ml 1. Overall, the management of PVT requires a comprehensive approach that takes into account the individual patient's risk factors, underlying conditions, and clinical presentation, with the goal of preventing complications and improving outcomes.

From the Research

Portal Vein Thrombosis Overview

• Portal vein thrombosis (PVT) is the most frequent among the splanchnic vein thrombosis, accounting for 90% of cases 2
• More than half of PVT are provoked by liver cirrhosis, solid cancer or myeloproliferative neoplasms 2
• The remaining cases are non-malignant non-cirrhotic PVT and include either unprovoked events or thrombosis secondary to other less common risk factors 2

Treatment and Management

• 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 2
• Different treatment options (unfractionated or low molecular weight heparin, vitamin K antagonists and direct oral anticoagulants [DOACs]) can be considered 2
• Anticoagulation therapy with warfarin is safe and effective for the prevention of PVST in cirrhotic patients with portal hypertension after laparoscopic splenectomy and azygoportal disconnection 3
• Low-molecular-weight heparin and vitamin K antagonist have a similar safety profile without specific data in favor of any of them 4

Associated Factors and Prognosis

• Thrombocytopenia, hypersensitive c-reactive protein >3 mg/L, anti β2GPI positive and aPL double-positive are independent associated factors for PVT in antiphospholipid syndrome (APS) patients 5
• Early diagnosis and anticoagulation treatment can bring thrombus re-canalization thereby significantly improving the prognosis 5
• Effective anticoagulation could increase re-canalization rate significantly, with better prognosis (lower mortality rate) 5

Future Clinical Studies

• Endpoints for future clinical studies in PVT, both in patients with and without cirrhosis, include classification of portal vein thrombus extension, classification of PVT evolution, timing of assessment of PVT, and global endpoints for studies on PVT including clinical outcomes 6
• These endpoints will help homogenise studies on PVT and thus facilitate reporting, comparison between studies, and validation of future studies and trials on PVT 6