The Viatorr stent-graft device has a bare lower end that lies in the portal vein (arrow) and an upper covered end that bridges the liver parenchymal tract (arrowheads); the transition between the two is marked by an opaque ring (open arrow). When appropriately positioned, the bare end in the portal vein allows flow into the intrahepatic portal veins and the covered segment prevents intimal hyperplasia from blocking the shunt