Portal vein thrombosis, cirrhosis, and liver transplantation.

Portal vein thrombosis is not uncommon in candidates for transplantation. Partial thrombosis is more common than complete thrombosis. Despite careful screening at evaluation, a number of patients are still found with previously unrecognized thrombosis per-operatively. The objective is to recanalize the portal vein or, if recanalization is not achievable, to prevent the extension of the thrombus so that a splanchnic vein can be used as the inflow vessel to restore physiological blood flow to the allograft. Anticoagulation during waiting time and transjugular intrahepatic portosystemic shunt (TIPS) are two options to achieve these goals. TIPS may achieve recanalization in patients with complete portal vein thrombosis. However, a marked impairment in liver function, which is a characteristic feature of most candidates for transplantation, may be a contraindication for TIPS. Importantly, the MELD score is artificially increased by the administration of vitamin K antagonists due to prolonged INR. When patency of the portal vein and/or superior mesenteric vein is not achieved, only non-anatomical techniques (renoportal anastomosis or cavoportal hemitransposition) can be performed. These techniques, which do not fully reverse portal hypertension, are associated with higher morbidity and mortality risks. Multivisceral transplantation including the liver and small bowel needs to be evaluated. In the absence of prothrombotic states that may persist after transplantation, there is no evidence that pre-transplant portal vein thrombosis justifies long term anticoagulation post-transplantation, provided portal flow has been restored through conventional end-to-end portal anastomosis.