Portosystemic shunt with hyperammonemia and high cardiac output as a complication after Fontan surgery.

In the late phase after Fontan surgery, organ dysfunction due to high central venous pressure (CVP) is a major clinical problem. We have described the cases of two patients with portosystemic shunts who exhibited hyperammonemia and high cardiac output associated with peripheral vasodilatation after Fontan surgery. A high CVP in these patients may have resulted in the formation of a portosystemic shunt. We performed coil embolization and balloon-occluded retrograde transvenous obliteration for each case. The possibility of a portosystemic shunt as a postoperative complication of Fontan surgery should always be considered. Early detection and therapeutic intervention seem necessary from the viewpoint of stabilizing the Fontan circulation and delaying the progression of liver disorder. < A portosystemic shunt may develop due to the high central venous pressure after Fontan surgery independent of hepatic disorder and should be considered as a potential cause of unexplained hyperammonemia and high cardiac output status. Transcatheter closure of the portosystemic shunt may improve the clinical status.>.