Recanalized umbilical vein conduit for meso-Rex bypass in extrahepatic portal vein obstruction.

BACKGROUND: Meso-Rex bypass is used to treat patients with clinically important extrahepatic portal vein obstruction (EHPVO). Usually, an autologous left internal jugular vein graft is used to bypass the portal blood circulation from the superior mesenteric vein to the left portal vein. Other vascular conduits have included the autogenous saphenous vein, splenic vein, right gastroepiploic vein, and inferior mesenteric vein.

METHODS: A total of 20 umbilical veins with attached livers were harvested from 20 deceased liver donors. Umbilical veins were dilated mechanically and checked for patency and communication with the left portal vein. Vein length and diameter after dilatation were recorded. Cross-sections of 15 recanalized umbilical veins were processed by routine histologic examination and stained with hematoxylin and eosin, as well as processed by immunohistochemistry for CD31 and factor VIII antigens. Subsequently, 3 children with EHPVO underwent this modified meso-Rex bypass using the umbilical vein as a vascular conduit.

RESULTS: The mean length of harvested umbilical veins was 15 cm (range, 7-21); the mean length of recanalized and usable umbilical veins was 10 cm (range, 5-15). Recanalization was successful in 16 (80%) of the 20 donor umbilical veins. The mean diameter of the umbilical veins after serial dilatation and recanalization was 1.2 cm (range, 1-2). In 11 (73%) of the 15 recanalized vein specimens, the lumen was lined by endothelial cells. In 2 children, the vascular conduit was constructed entirely with native umbilical vein. In the remaining child, 3 cm of umbilical vein was preserved and anastomosed to a mobilized inferior mesenteric vein due to inadequate length. All 3 children had patent bypass and resolution of clinical manifestations of portal hypertension at a mean follow-up of 21 months.

CONCLUSION: Meso-Rex bypass may prove to be a definitive treatment for patients with EHPVO. The use of native umbilical vein as a vein conduit achieved decompression of the splanchnic venous system and should be considered a natural alternative to other interposition vein grafts.