Background.
Donor liver biopsy (DLBx) in liver transplantation provides information on allograft quality; however, predicting outcomes from these allografts remains difficult.
Methods.
Between 2006 and 2015, 16 691 transplants with DLBx were identified from the Standard Transplant Analysis and Research database. Cox proportional hazard regression analyses identified donor and recipient characteristics associated with 30-d, 90-d, 1-y, and 3-y graft survival. A composite model, the Liver Transplant After Biopsy (LTAB) score, was created. The Mini-LTAB was then derived consisting of only donor age, macrosteatosis on DLBx, recipient model for end-stage liver disease score, and cold ischemic time. Risk groups were identified for each score and graft survival was evaluated. P values <0.05 were considered significant.
Results.
The LTAB model used 14 variables and 5 risk groups and identified low-, mild-, moderate-, high-, and severe-risk groups. Compared with moderate-risk recipients, severe-risk recipients had increased risk of graft loss at 30 d (hazard ratio, 3.270; 95% confidence interval, 2.568-4.120) and at 1 y (2.258; 1.928-2.544). The Mini-LTAB model identified low-, moderate-, and high-risk groups. Graft survival in Mini-LTAB high-risk transplants was significantly lower than moderate- or low-risk transplants at all time points.
Conclusions.
The LTAB and Mini-LTAB scores represent guiding principles and provide clinically useful tools for the successful selection and utilization of marginal allografts in liver transplantation.
Liver transplantation (LT) represents the sole curative option for patients with end-stage liver disease (ESLD); however, there remains a persistent unmet need for donor organs. To overcome the deficit in available allografts, the utilization of marginal organs has been widely promoted. However, this movement is balanced by the need to maintain excellent recipient outcomes.
Donor liver biopsy (DLBx) is used to evaluate questionable or marginal donors and provides information on fibrosis, necrosis, and levels of macrosteatosis (MaS). Historically, allografts with high levels of MaS, typically defined as >30%, have been associated with early allograft dysfunction (EAD), primary nonfunction (PNF), and worse outcomes overall.1–3 Despite this, multiple single-center studies have shown successful allograft and patient survival with the use of highly steatotic allografts, even up to 90% MaS.4–7 This has been further supported by a recent study showing that allografts with MaS >30% have better survival in the current transplant era compared with those used 10 y ago.8 Separately, our group showed equivalent 1-y graft survival for liver allografts with up to 50% MaS when used in recipients with model for end-stage liver disease (MELD) scores <33 and up to 40% MaS in higher MELD recipients.9 Together, these findings support the use of increasingly steatotic allografts with attention to recipient selection.
The influence of donor characteristics on transplant outcomes was first described by the Donor Risk Index (DRI).10 While difficult to calculate, this score has been additionally critiqued for its overall poor predictive ability.11 In 2011, de Graaf et al12 showed that severe allograft MaS >30% carried a greater impact on graft survival than the DRI alone. Attempts to include graft MaS into scoring systems predicting graft survival have been undertaken; however, these are limited by the incorporation of organs with MaS >30% into a single risk group.3,13 This unfortunately limits the ability to apply these scoring systems, in light of new findings supporting the use of higher MaS organs.
The aim of the present study is to develop a simple, clinically useful, scoring system to risk stratify LT for marginal donors undergoing DLBx. By identifying donor and recipient characteristics significantly associated with increased risk of graft loss, we created the Liver Transplant After Biopsy (LTAB) score, as well as a more clinically useful Mini-LTAB, to risk stratify donor–recipient pairs in LT after DLBx.