Graft Survival and Segment Discards Among Split-Liver and Reduced-Size Transplantations in the United States From 2008 to 2018

Abstract

Split-liver transplantation has allocation advantages over reduced-size transplantation because of its ability to benefit 2 recipients. However, prioritization of split-liver transplantation relies on the following 3 major assumptions that have never been tested in the United States: similar long-term transplant recipient outcomes, lower incidence of segment discard among split-liver procurements, and discard of segments among reduced-size procurements that would be otherwise "transplantable." We used United Network for Organ Sharing Standard Transplant Analysis and Research data to identify all split-liver (n = 1831) and reduced-size (n = 578) transplantation episodes in the United States between 2008 and 2018. Multivariable Cox proportional hazards modeling was used to compare 7-year all-cause graft loss between cohorts. Secondary analyses included etiology of 30-day all-cause graft loss events as well as the incidence and anatomy of discarded segments. We found no difference in 7-year all-cause graft loss (adjusted hazard ratio [aHR], 1.1; 95% confidence interval [CI], 0.8-1.5) or 30-day all-cause graft loss (aHR, 1.1; 95% CI, 0.7-1.8) between split-liver and reduced-size cohorts. Vascular thrombosis was the most common etiology of 30-day all-cause graft loss for both cohorts (56.4% versus 61.8% of 30-day graft losses; P = 0.85). Finally, reduced-size transplantation was associated with a significantly higher incidence of segment discard (50.0% versus 8.7%) that were overwhelmingly right-sided liver segments (93.6% versus 30.3%). Our results support the prioritization of split-liver over reduced-size transplantation whenever technically feasible.