New Evidence Supporting Increased Use of Split Liver Transplantation.

Background: Young children and small-statured candidates are dying on liver candidate waitlists. The Organ Procurement and Transplantation Network and United Network for Organ Sharing have proposed a split liver (SL) variance encouraging transplant programs to split more livers to aid these smaller statured candidates.

Methods: We evaluated the US experience of splitting donor livers during 2002-2016. The results of our analysis provide new evidence to support this variance.

Results: During 2002-2016, SL grafts from 935 donors were transplanted into 1870 recipients. Controlling for recipient factors and using time period and program identification as random variables, a multivariable mixed Cox proportional hazards model for graft failure revealed that donor aged 3-10 years had a relative risk (RR) of 3.94 (2.86-5.44), and donor aged >30 years had a RR of 1.94 (1.59-2.35) for graft failure. Donor-to-recipient body surface area ratio <0.90 had a RR of 1.40 (1.13-1.75). Programs with experience transplanting <23 SLs had a RR of 1.43 (1.21-1.75). The same program transplanting both split segments had a RR of 1.38 (1.20-1.59).

Conclusions: Splitting protocols based on these findings could improve graft survival after SL transplantation, which would encourage programs to opt into splitting more livers. The new protocols may consider donor age restrictions, necessary program experience, donor with body surface area appropriate for recipient, and improved logistical factors to share segments between transplant programs. The result would likely be a drastic reduction in liver waitlist deaths for young children and small-statured candidates.