Improving outcomes of in situ split liver transplantation in Italy over the last 25 years

Background & aims: Split liver transplantation (SLT) is still considered a challenging procedure, by no means widely accepted. We aimed to present 25-year trends in SLT in Italy, and to investigate if, and to what extent, outcomes have improved nationwide during this time. Methods: The study included all consecutive SLTs performed from May 1993 to December 2019, divided into three consecutive periods: 1993-2005, 2006-2014, and 2015-2019, which match changes in national allocation policies. Primary outcomes were patient and graft survival, and the relative impact of each study period. Results: SLT accounted for 8.9% of all liver transplants performed in Italy. 1,715 in-situ split liver grafts were included in the analysis: 868 left lateral segments (LLSs) and 847 extended right grafts (ERGs). A significant improvement in patient and graft survival (p<0.001) was observed in ERG outcomes over the three periods. Predictors of graft survival were CIT <6h (p=0.009), UNOS status 2b (p<0.001), UNOS status 3 (p=0.009), and transplant centre volumes: 25-50 cases vs. <25 cases (p=0.003). LLS grafts showed a significantly higher patient survival in period 2 vs. period 1 (p=0.008). No significant improvement in graft survival was seen over the 3 periods where predictors of graft survival were CIT<6h (p= 0.007), CIT<6h vs. ≥10h (p=0.019), UNOS status 2b (p=0.038), and UNOS status 3 (p=0.009). Retransplantation was a risk factor in split-liver graft recipients, with significantly worse graft and patient survival for both types of graft (p <0.001). Conclusions: Our analysis showed Italian SLT outcomes to have improved over the last 25 years. These results could help to dispel reservations regarding the use of this procedure. Impact and implications: Split liver transplantation (SLT) is still considered a challenging procedure, and by no means widely accepted. This study included all consecutive in-situ SLTs performed in Italy from May 1993 to December 2019. With more than 1,700 cases, it is one of the largest series, examining long-term national trends of in-situ SLT since its introduction. The data presented indicate improved outcomes using split liver grafts over 25 years of experience. Improvements are probably due to better recipient selection, refinements in surgical technique, conservative graft-to-recipient matching, and the continuous, yet carefully managed, expansion of donor selection criteria under a strict mandatory split liver allocation policy. These results could help to dispel reservations regarding the use of this procedure.