Excessive portal flow causes graft nonfunction in small size liver transplantation: an experimental study in pigs

We investigated the effects of portocaval shunt (PCS) on excessive portal flow in producing sinusoidal microcirculatory injury in small-for-size liver transplants in pigs. The posterior segment of a whole liver (25%) was transplanted orthotopically. The pigs were divided two groups: group A, graft with PCS (n = 11), and group B, graft without PCS (n = 11). The PCS was a side-to-side anastomosis of the portal vein and the inferior vena cava. In group A, eight pigs survived for more than 4 days; all pigs except for one died of graft nonfunction within 24 hours in group B. The portal flow after reperfusion decreased in group A, but increased about three times greater in group B than that before the operation (P < .01). In group B, destruction of the sinusoidal lining and bleeding in the periportal areas were observed after reperfusion, findings that were not recognized in group A. These results suggest that graft nonfunction after small-for-size liver transplantation may be attributable to excessive portal flow producing sinusoidal microcirculatory injury.