Portal Vein Cavernous Transformation

Cavernous transformation of the portal vein is the formation of a network of collateral hepatopetal veins around an occluded portal vein, as a response to chronic portal vein thrombosis.

• Develops within 1 to 5 weeks of portal vein obstruction.
• Causes in adults: cirrhosis, myeloproliferative neoplasm (JAK2), prothrombotic states, abdominal sepsis or surgery, pancreatitis, malignancy.
• Children: omphalitis, umbilical vein catheterisation, congenital portal vein anomalies; extrahepatic portal vein obstruction is a leading cause of portal hypertension in children in developing regions.
• Portal hypertension is presinusoidal, with preserved liver function.
• Complications: variceal bleeding (oesophageal, gastric, ectopic), hypersplenism, portal biliopathy, growth failure and minimal encephalopathy in children.

• Variceal bleeding with preserved liver function (often the presenting event).
• Splenomegaly, thrombocytopenia, leucopenia, anaemia.
• Ascites is uncommon unless liver disease coexists.
• Biliary symptoms: jaundice, cholangitis, biliary pain (portal biliopathy).
• Growth retardation in children.

• Doppler ultrasound: absent normal portal vein, tangle of tortuous collaterals ("honeycomb" or cavernoma) in the porta hepatis.
• CT or MR angiography to define extent, superior mesenteric and splenic vein patency, and portosystemic collaterals.
• Endoscopy for varices and gastropathy.
• Thrombophilia screen (JAK2, CALR, antiphospholipid antibodies, factor V Leiden, prothrombin gene, protein C and S, PNH).
• Liver function and elastography to exclude cirrhosis; MRCP for biliary involvement.
• Assess hypersplenism (platelet count, spleen size).

• Variceal bleeding: octreotide 50 micrograms IV bolus then 50 micrograms/h, ceftriaxone 1 g daily, endoscopic band ligation.
• Secondary prophylaxis: band ligation every 2 to 4 weeks until eradication, plus non selective beta blocker (propranolol 40 to 160 mg daily or carvedilol 6.25 to 12.5 mg daily).
• Primary prophylaxis for large varices: carvedilol or band ligation.
• Anticoagulation for recent thrombosis (under 6 months) or a prothrombotic condition: LMWH then warfarin or DOAC for at least 6 months, lifelong in thrombophilia, with banding first for high risk varices.
• Children: Meso Rex bypass (mesenteric to left portal vein) restores portal flow when a patent intrahepatic left portal vein exists; otherwise distal splenorenal shunt or proximal splenorenal shunt.
• Rescue procedures: surgical shunts, TIPS (technically difficult, recanalisation), splenic embolisation or splenectomy for symptomatic hypersplenism.
• Portal biliopathy treated as per its own measures.
• Follow up endoscopy every 6 to 12 months and growth in children.