Imaging the Rex vein preoperatively using wedged hepatic venous portography

Mesentericoportal bypass, the Rex shunt, restores the physiological hepatic portal flow and reduces the clinical sequelae of portal hypertension in children with extrahepatic portal vein obstruction (EHPVO). The preoperative evaluation includes an accurate assessment of the portal venous inflow and outflow. The former is readily assessed by ultrasound and MRI, while the outflow intrahepatic portal vein is harder to assess. To assess the efficacy of wedged hepatic venous portography (WHVP) at detecting a patent Rex vein preoperatively in children with EHPVO who were considered for mesenterico-portal bypass. A single-institution retrospective chart review was undertaken for children with EHPVO who had been considered for a mesoportal bypass between January 2001 and January 2010. Sixteen children were considered for mesoportal bypass, including four post reduced-size liver transplant patients. Ten children (63%) underwent WHVP. The Rex vein was clearly identified in 8/10 (80%). One Rex vein was seen at surgery but not demonstrated at WHVP. Six mesoportal bypasses were performed without WHVP, of which three (50%) were successful. WHVP had a sensitivity of more than 80% and specificity of 100% in the preoperative patency assessment of the Rex vein.