Learning Objectives: 1. Review the anatomy of different types of Abernethy malformations.
2. Learn the long-term complications of untreated congenital portosystemic shunts.
3. Understand interventional radiology’s role in treating patients with Abernethy malformation.
Background: Congenital extrahepatic portosystemic shunts, also known as Abernethy malformations, are rare but important to recognize vascular anomalies which can have significant impacts on long-term hepatic health and survival for affected pediatric patients {1}. Type II Abernethy malformations can be corrected by interventional radiologists through selective occlusion of the abnormal portosystemic shunt, thereby improving portal venous flow and mitigating associated chronic complications {2}.
Clinical Findings/Procedure Details: Abernethy malformations are vascular anomalies of the portal venous system which result in shunting of blood flow from the splanchnic vessels directly to systemic circulation, usually via the inferior vena cava. Type I Abernethy malformations are subdivided: Type Ia shows complete absence of the portal vein (splenic and superior mesenteric veins connect directly to the IVC) while Type Ib has an extrahepatic portal vein which connects directly to the IVC and does not supply the liver. Type II Abernethy malformations show an anomalous side-to-side venous connection between a diminutive extrahepatic portal vein and the IVC.
The morbidity associated with untreated Abernethy malformation includes hepatic encephalopathy, development of benign and malignant hepatic lesions, hepatopulmonary syndrome, and pulmonary hypertension. A recently published 66-patient case series described long-term outcomes for those with both corrected and uncorrected shunts {2}. Type II Abernethy malformations can be treated with endovascular occlusion of the side-to-side portosystemic shunt, usually with large caliber occlusion devices such as an Amplatzer plug.
Conclusion and/or Teaching Points: Though Abernethy malformations are rare, interventional radiologists must be aware of the long-term health impact of untreated congenital portosystemic shunts and provide referring clinicians with appropriate guidance about their management. Type II (side-to-side) Abernethy malformations can be corrected via endovascular occlusion of the abnormal venous connection between the splanchnic vessels and systemic circulation.
