Abernethy malformation type Ib

Case Discussion

After the appearance of contractions, the mother was examined at the ED and a fetal US was performed which demonstrated absence of an intrahepatic portal system. It was decided to induce labor after 3 more weeks, for fear of fetal heart failure.
Postnatally, US Doppler (unavailable) demonstrated a portosystemic shunt. There was debate as to whether or not a portal system was present, as there were apparent differences between findings on 3 consecutive US studies.
MRA abdomen (unavailable) done ~1 month before the venography showed an extrahepatic shunt connecting the portal vein to the IVC, with substantial flow through it - appeared compatible with an Abernethy malformation type Ib. Referred for venography with temporary balloon occlusion of the shunt in order to assess the extent of the intrahepatic portal venous system and the hemodynamic repercussions of closing off this system, as the prospects of shunt reduction/closure are dependent on its anatomy.

During diagnostic catheterization, the malformation was demonstrated, showing drainage of the SMV into the infrahepatic IVC through a short, wide channel. A hypoplastic portal system was seen. No intervention was attempted during the procedure, as the shunt could not be occluded in one stage without impacting flow through the IVC or the common portal vein.

Surgery was recommended: either external shunt banding or a fenestrated patch across the orifice.