OBJECTIVE:We describe the angiographic diagnosis and significance of persistence of the primitive hepatic venous plexus with underdevelopment of the infrahepatic inferior vena cava. CONCLUSION:We recommend that inferior venacavography be performed in routine assessment before surgery of patients with azygos or hemiazygos continuation of the inferior vena cava, in whom redirection of systemic venous blood to the pulmonary artery is contemplated.