Portal vein thrombosis

Portal vein thrombosis (PVT) refers to complete or partial closure of the portal vein due to a thrombus. Underlying causes include cirrhosis and malignancy. Acute PVT may present with abdominal pain and ascites, whereas chronic PVT is often asymptomatic. PVT is typically diagnosed with imaging demonstrating thrombus in the portal vein. Treatment depends on the acuity and whether there is underlying cirrhosis and typically consists of anticoagulation or thrombolysis; TIPS may be indicated in select cases.

• Cirrhosis or chronic liver disease
• Local complications of intraabdominal malignancy (e.g., HCC, pancreatic carcinoma) or inflammation (e.g., liver abscess, pancreatitis, cholangitis)
• Thrombophilia (e.g., antiphospholipid syndrome, factor V Leiden) or general risk factors of phlebothrombosis
• Myeloproliferative disorder
• Following TIPS procedure
• Chronic mesenteric venous thrombosis

• Possibly caused by an imbalance of coagulation factors in patients with impaired hepatic synthetic function
• The closure of portal vein flow → ↓ liver blood flow → vasodilation of the hepatic artery and development of collateral hepatic veins in an attempt to maintain liver perfusion
• Thrombotic closure of the splenic and superior mesenteric veins may extend to the portal vein → portal hypertension

Depend on the extent of thrombosis and the speed of manifestation

• Acute PVT
  • Abdominal pain (RUQ or generalized)
  • Splenomegaly
  • Fever
  • Ascites
• Chronic PVT
  • In cirrhotic patients, chronic PVT is often asymptomatic (incidental finding on ultrasound).
  • Abdominal pain (RUQ or generalized)
  • Esophageal variceal hemorrhage
  • Hepatic encephalopathy
  • Splenomegaly and hypersplenism
  • Jaundice and pruritus due to portal cholangiopathy

• Duplex ultrasound: decreased flow velocity or no flow in the portal vein
• Other abdominal ultrasound findings ^[1]
  • Portal cavernoma
  • Variable portion of mostly echogenic thrombus material in the portal vein
  • Widening of the portal vein
  • Dilated, coiled periportal veins
  • Hyperechoic or isoechoic thrombus in the portal vein
• CT or MRI abdomen (with contrast): to simultaneously investigate other abdominal organs and for patients with suspected cancer ^[1]
• Other studies
  • Liver chemistries: typically normal ^[1]
  • Screening for myeloproliferative and thrombophilic disorders: indicated in patients without cirrhosis to investigate the etiology of PVT (guided by hematology) ^[2]
  • Endoscopy: Variceal bleed is the initial symptom of PVT in up to 40% of cases. ^[1]

If PVT is detected in patients with cirrhosis, HCC must be ruled out as the cause. ^[2]

PVT can initially present with variceal bleed. Patients presenting with PVT should undergo screening for varices with upper GI endoscopy. ^[1]

Approach ^[2][3]

• All patients: Management is guided by the presumed time of onset of thrombosis and the degree of suspicion of intestinal ischemia.
  • Recent PVT and suspicion of intestinal ischemia: anticoagulation and surgery in patients with intestinal infarction
  • Chronic complete PVT: Focus on the management of portal hypertension sequelae.
• Patients with cirrhosis: Individualize treatment based on the degree of occlusion and other symptoms.
• Patients without cirrhosis with recent PVT: Consider anticoagulation.

Management of PVT (e.g., anticoagulation) is determined on a case-by-case basis and specialists should be involved early.

Anticoagulation

For patients with cirrhosis, the choice of anticoagulant should be individualized and guided by a hematologist. Data on the safety of direct oral anticoagulants in cirrhosis is scarce. ^[2]

• Traditional anticoagulants ^[2][3]
  • Start low molecular weight heparin (e.g., enoxaparin) OR unfractionated heparin.
  • Continue low molecular weight heparin and initiate an oral vitamin K antagonist (e.g., warfarin) in parallel (i.e., bridging anticoagulation) until the patient's INR is within the therapeutic range (usually 2–3).
• Direct oral anticoagulants: e.g., apixaban

Surgical or interventional procedures ^[2]

• Pharmacological thrombolysis (local or systemic): Consider in selected patients with persistent ischemia despite anticoagulation.
• TIPS placement: can be considered in selected cases