Split liver transplantation: Will it ever yield grafts for two adults?

In 1984, with mortality on the pediatric liver transplant waiting list reaching 25% at major centers, Bismuth et al. described the first partial liver transplant of a large graft into a small child. Their report was later confirmed by Broelsch and others, with success equal to or better than that of cadaveric whole liver transplantation in children. Yet although the waiting time for pediatric livers was shortened, the practice of discarding the right hemiliver shifted the cost to the adult waiting list. In 1989, Bismuth et al. and Pichlmayr et al. simultaneously reported the first instances of split liver transplantation (SLT), in which adult/child pairs received grafts from a single cadaveric donor. After initial enthusiasm, however, discouraging outcomes of SLT versus cadaveric whole liver transplantation and living donor liver transplantation caused interest to fall. With technical refinements from experience in living donor liver transplantation and a better understanding of partial graft failure, SLT was reinvestigated in the late 1990s. The University of Hamburg in 1996 and the University of California–Los Angeles in 1997 reported adult and pediatric graft/patient survival comparable to that with whole liver transplantation. Although splitting a liver between an adult and a child is known to be effective, data on SLT between 2 adults [adult-to-adult split liver transplantation (A/A SLT)] are scarce. The first A/A SLT was described by Bismuth et al. in 1989. Only a few reports followed the first one, reflecting the challenge of the procedure. In the largest series, by Azoulay et al., patient survival and graft survival with right-lobe grafts were comparable to those with whole liver transplantation. Left-lobe grafts had a higher risk of primary nonfunction, mostly related to size inadequacy, but patient survival was comparable to survival in whole liver recipients (patients with primary nonfunction underwent retransplantation), and this led the authors to conclude that SLT between adults is technically feasible. In the first North American series of 12 A/A SLT procedures, patient and graft survival at 9 months was 89% for right-lobe grafts versus 78% for left-lobe grafts. Biliary complications were a frequent cause of morbidity (27%), followed by an 11% incidence of vascular complications that resulted in 2 deaths. Complications were observed in 26% of left-graft SLT recipients and 22% of right-graft SLT recipients. Renz et al. observed a similar pattern in their series: more frequent vascular complications in right-lobe grafts, more frequent biliary complications in left-lobe grafts, higher graft survival in right-lobe recipients, and rates of primary nonfunction and recipient death similar to those reported by others. In this issue of Liver Transplantation, 2 articles draw very different conclusions about A/A SLT. Giacomoni et al. found “compelling evidence of a poorer reliability of SLT for 2 adults.” Heaton et al., on the other hand, advise that we proceed with A/A SLT in combination with living donor liver grafts, when possible, to improve outcomes. In the report by Giacomoni et al., 1-year survival was 69% for SLT recipients versus 87% in a control group of whole-graft recipients. Five of the 16 SLT patients died of early allograft dysfunction before they could undergo retransplantation. Retransplantation, however, is crucial in making SLT a justifiable proce-