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

From the Guidelines

Portal vein thrombosis (PVT) is primarily caused by thrombosis, which can lead to cavernomatous transformation of the portal vein, and its symptoms include abdominal pain, rectal bleeding, and ascites, as evident from the EASL clinical practice guidelines 1. The causes of PVT can be categorized into three mechanisms: malignant invasion, portal vein narrowing within a malignant tumor, and thrombosis, with thrombosis being the most relevant mechanism in this context 1. The symptoms of PVT can vary, but common presentations include abdominal pain, which should prompt consideration of the diagnosis of acute portal vein obstruction 1. Other symptoms and complications of PVT include:

• Intestinal infarction, which should be considered in patients with persisting severe abdominal pain, rectal bleeding, moderate or massive ascites, or multiorgan dysfunction 1
• Gastroesophageal varices, which can develop in over half of the patients not achieving recanalisation 1
• Severe portal biliopathy, which can develop in 30% of patients with acute PVT within 1 year 1
• Ascites, with a two-year actual probability of 16% 1
• Variceal bleeding, with a two-year actual probability of 12% 1

The diagnosis of PVT should be considered in any patient with abdominal pain, and Doppler ultrasound should be used as the first line investigation, followed by CT for diagnostic confirmation and assessment of extension 1. In patients with cirrhosis and PVT, evidence of intestinal ischemia requires urgent anticoagulation to minimize ischemic injury, as stated in the AGA clinical practice update 1. Clinical features concerning for ischemia include abdominal pain out of proportion to examination, sepsis, elevated lactate, and imaging findings such as mesenteric fat stranding or dilated bowel loops 1. Timely anticoagulation significantly decreases the need for bowel resection and improves mortality, and interventional approaches with thrombectomy and thrombolysis have also been successful and should be considered if no clinical improvement is observed with anticoagulation 1.

Anticoagulation therapy should be initiated immediately with low molecular weight heparin (LMWH) in the absence of major contraindications, and oral anticoagulants such as warfarin or direct oral anticoagulants (DOACs) should be used for long-term anticoagulant treatment, targeting an INR between 2 and 3 1. The treatment duration should be at least 6 months, and patients should be monitored with regular ultrasound examinations to assess clot resolution 1. Underlying causes such as cirrhosis, malignancy, or thrombophilia should be addressed simultaneously, and patients should be advised to stay hydrated, avoid prolonged immobility, and report any symptoms of abdominal pain, bloating, or gastrointestinal bleeding immediately.

From the Research

Causes of Portal Vein Thrombosis (PVT)

• Liver cirrhosis, solid cancer, or myeloproliferative neoplasms are the most common causes of PVT, accounting for more than half of the cases 2
• Non-malignant non-cirrhotic PVT can be caused by abdominal surgery, intrabdominal inflammations/infections, or hormonal stimuli 2
• Myeloproliferative disorder, liver cirrhosis with portal hypertension, deficiency of natural anticoagulant proteins, gene mutation, and hepatocellular carcinoma are also frequent causes of PVT 3

Symptoms of Portal Vein Thrombosis (PVT)

• Gastroesophageal varices can occur as a result of PVT, but do not represent a contraindication to anticoagulant treatment 2
• Patients with PVT are at risk of negative long-term outcomes related to complications of portal hypertension, such as variceal bleeding, ascites, and portal cholangiopathy 4
• Intestinal infarction can occur in cases of acute extensive portal vein thrombosis 4

Diagnosis and Treatment of PVT

• Imaging methods such as sonography, color Doppler sonography, contrast-enhanced 3D MR angiography, and digital subtraction angiography can be used to diagnose PVT 3
• Anticoagulant therapy 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, including unfractionated or low molecular weight heparin, vitamin K antagonists, and direct oral anticoagulants (DOACs), can be considered 2, 5