Patterns of portal vein occlusion and their aetiological significance.

Clinical and angiographic findings in 53 patients with portal vein occlusion were reviewed to determine the relationship between the pattern of venous occlusion and its aetiology. Five major patterns were identified. Group 1 comprised three children with idiopathic intrahepatic portal vein occlusion alone (hepatoportal sclerosis). Those in group 2 (25 patients), with occlusion of the main portal vein, accounted for almost half the total number and for most of those with a probable congenital aetiology. The ten patients in group 3 had angiographic occlusion and collateralization of the main portal and superior mesenteric veins. Intra-abdominal sepsis, other than that from pancreatic disease, was associated with this pattern of venous occlusion in which the splenic vein is spared. No patients with isolated portal and splenic vein occlusion (group 4) were recorded. Widespread thrombosis throughout the portal venous system (group 5; 15 patients) had a multifactorial aetiology but was typically observed in hypercoagulable states that were also associated with hepatic vein occlusion or other deep vein thromboses.