Background/aims: In the animal model of auxiliary partial liver transplantation in the rat, the major problem is high outflow pressure since the direction of vascular outflow of the graft was perpendicular to that of the recipient inferior vena cava (IVC) and the anastomosis was far away from the right atrium. We aimed at developing an animal model that could prevent graft congestion.
Methodology: The graft contained the right lateral lobe and triangulated lobe of rat's liver. The modification of implantation included anatomizing an oblique cuff of IVC of donor graft into the recipient's IVC so that the size of anastomosis was large with an angle of 45 degrees and the resulting vascular outflow was no longer perpendicular to that of the recipient's IVC, and the creation of double grooves on the cuff body of the donor portal vein. Bile drainage was completed by inserting the bile duct (together with a stent) into the recipient's duodenum.
Results: Congestion of grafts was not seen in 25 rats undergoing auxiliary partial liver transplantation using an oblique IVC graft. The 1-week and 2-week survival rates were 88% and 80%, respectively. In the group of rats (n = 10) operated on by using a straight IVC graft, graft congestion was seen and only 1 rat could survive over 1 day.
Conclusions: Modification of vascular outflow anastomosis prevented graft congestion and improved animal survival. The model may be useful for studying liver regeneration, transplantation immunology, and gene transfer.