Portal Vein Complications

Split liver transplantation may be technically challenging due to the short vascular pedicles. During the operation, vascular extensions with vascular grafts may be necessary to complete the procedure. In addition to the short vascular pedicles intrinsic to the graft, many small children with biliary atresia have sclerotic, small-diameter portal veins. 
Removing of the sclerotic segment and placing the portal vein anastomosis at the confluence of the superior mesenteric and splenic vein may increase flow and provide better long term patency. The incidence of portal vein thrombosis varies in several reported series from 0 to 33% &, and is generally much greater than that observed in adult recipients. Several factors probably influence the development of portal vein complications in children: type of graft utilized, portal vein size, and positional factors.
In our series, portal vein complications occurred in 6 (9%) split liver recipients. Incidence of portal complications in our series of split liver transplant was in the upper range, all in small children. The triangulation technique adopted for the left hepatic vein anastomosis decreased the graft’s rotation to the right, reducing the risk for portal vein strictures. We  dissected the recipient’s extrahepatic portal vein, even if slightly sclerotic, past the primary portal branches obtaining an adequate length of portal vein to anastomose to the graft left branch of the portal vein. We limited the use of interposition venous grafts to very sclerotic and small portal veins of patients with biliary atresia, performing the anastomosis to the confluence of the splenic vein and superior mesenteric vein. Five out of 6 split liver recipients developing portal vein thrombosis were transplanted for extrahepatic biliary atresia and two required an interposition graft. Another possible risk factor in the development of portal vein thrombosis is the volume of the transplanted graft. The tight closure of the abdomen following very large-to-size liver grafts, particularly in small children, can result in impaired perfusion of the graft, high intrahepatic vascular resistance and portal vein thrombosis. In our series, one patient, transplanted for acute liver failure of unknown ethiology with a left lateral segment with donor to recipient body weight ratio of 17.6, developed portal vein occlusion. The extensive use of delayed abdominal closure adopted by others might help to address this issue &.