Liver transplantation in pigs with von Willebrand's disease.

Nine pigs with von Willebrand's disease (vWd pigs) received normal auxiliary livers; in the immediate postoperative period, three pigs died, three survived from 3 days to 3 weeks, and three were killed 5-13 weeks postoperatively. There was an increase in factor VIII (up to 90 u/dl) but with a type of factor VIII that was more labile than normal and that decreased after 2 weeks, probably as a result of liver rejection. There was a slight increase in the levels of the ristocetin-Willebrand factor postoperatively (up to 11%) but this activity was undetectable after 2 weeks. There was no correction of the abnormal bleeding time and platelet retention. When a vWd liver was transplanted orthotopically into a normal pig, the factor-VIII coagulant activity and the ristocetin-Willebrand factor remained normal. The abnormality in porcine von Willebrand's disease is only partially corrected by liver transplantation, which suggests that there also is extrahepatic synthesis of the missing or abnormal plasmatic activity or activities.