Effect of centre volume and high donor risk index on liver allograft survival

Background: A growth in the utilization of high-risk allografts is reflective of a critical national shortage and the increasing waiting list mortality. Using risk-adjusted models, the aim of the present study was to determine whether a volume-outcome relationship existed among liver transplants at high risk for allograft failure. Methods: From 2002 to 2008, the Scientific Registry of Transplant Recipients (SRTR) database for all adult deceased donor liver transplants (n= 31 587) was queried. Transplant centres (n= 102) were categorized by volume into tertiles: low (LVC; 31 cases/year), medium (MVC: 64 cases/year) and high (HVC: 102 cases/year). Donor risk comparison groups were stratified by quartiles of the Donor Risk Index (DRI) spectrum: low risk (DRI 1.63), moderate risk (1.64 > DRI > 1.90), high risk (1.91 > DRI > 2.26) and very high risk (DRI 2.27). Results: HVC more frequently used higher-risk livers (median DRI: LVC: 1.82, MVC: 1.90, HVC: 1.97; P < 0.0001) and achieved better risk adjusted allograft survival outcomes compared with LVC (HR: 0.90, 95%CI: 0.85-0.95). For high and very high risk groups, transplantation at a HVC did contribute to improved graft survival [high risk: hazard ratio (HR): 0.85, 95% confidence interval (CI): 0.76-0.96; Very High Risk: HR: 0.88, 95%CI: 0.78-0.99]. Conclusion: While DRI remains an important aspect of allograft survival prediction models, liver transplantation at a HVC appears to result in improved allograft survival with high and very high risk DRI organs compared with LVC.