A 3-day old girl, born at 36 weeks’ gestation, presented with a cystic lesion of the pelvis seen on prenatal ultrasound and fetal MRI. On day one of life, an MRI/MRA of the abdomen/pelvis was obtained (A) and demonstrated a large abnormal vessel extending from the liver caudally with the tortuous path toward the right internal iliac vein (arrows). A large portosystemic shunt was suspected. A subsequent echocardiogram showed elevated right heart pressures. Abdominal ultrasound (B) was also performed demonstrating a “to and fro” flow within the main portal vein.
The patient was taken to the interventional radiology suite for a more detailed evaluation of the shunt. Left common femoral vein approach was chosen and accessed using a 21-gauge needle and microcatheter system without sheath. Through the right internal iliac vein, the shunt was accessed with retrograde navigation toward the liver. Contrast injection from the superior mesenteric vein (C, blue arrow) demonstrates a high-flow tortuous shunt directing flow away from the fusiform main portal vein to the right internal iliac vein (D, green arrow). Note the stasis of contrast within the dysgenic portal system (D, yellow arrow) demonstrating fusiform main portal vein and mildly hypoplastic portal veins.
The pressure gradient was measured without and with manual external pressure occluding the shunt to evaluate whether performing an embolization procedure would be safe. Occluding a shunt with a pressure gradient greater than 10 mmHg carries a risk of acute portal hypertensive complication.1 The gradient measured 6 mmHg and the shunt was successfully occluded with coils (E). Liver ultrasound performed the following day demonstrated monophasic antegrade/hepatopedal flow (F).
Congenital portosystemic shunts (Abernathy malformations) were described by Dr. Abernathy in 1793 and result from persistence of embryonic vessels. With advances in imaging, earlier identification of these congenital anomalies has allowed for potential earlier intervention. When left untreated, they may go unnoticed for years presenting as heart failure or hepatic encephalopathy.2 Smaller shunts may close spontaneously1 and can be monitored in the absence of acute sequelae such as heart failure.
Beydoun T, Nahl D. JAOCR at the Viewbox: Congenital Extrahepatic Portosystemic Shunt (Abernathy Malformation). J Am Osteopath Coll Radiol. 2021;10(3):28-29.
