Faculty Bibliography

Patient and graft survival are similar following whole versus split liver transplants (SLT) among pediatric and adult recipients, yet SLTs are rarely used. We sought to determine the survival benefit associated with accepting a splittable offer for SLT versus declining and waiting for a subsequent offer using 2010-2018 SRTR data on 928 pediatric and 1814 adult LT candidates who were ever offered a splittable graft. We compared eventual mortality, regardless of subsequent transplants, between those who accepted versus declined a splittable liver offer with adjustment for PELD/MELD, diagnosis, and weight among pediatric candidates, and matching for MELD, height, and offer among adult candidates. Among pediatric candidates ≤7kg, splittable offer acceptance versus decline was associated with a 63% reduction in mortality (aHR _0.17 0.37_0.80 , p=0.01; 93.1% versus 84.0% one-year survival post-decision). Within one year of decline for those ≤7kg, 6.4% died and 31.1% received a whole liver transplant. Among pediatric candidates >7kg, there was no significant difference associated with acceptance of a splittable offer (aHR _0.63 1.07_1.82 , p=0.81; 91.7% vs 94.4% one-year survival post-decision). Within one year of decline for those >7kg, 1.8% died and 45.8% received a whole liver. Among adult candidates, splittable offer acceptance was associated with a 43% reduction in mortality (aHR _0.39 0.57_0.83, p=0.005; 92.2% vs 84.4% one-year survival post-decision). Within one year of decline for adult candidates, 7.9% died and 39.3% received a whole liver. Conclusion: Accepting splittable offers for SLT could significantly improve survival for small children and adults on the waitlist.

Despite a documented survival benefit, older liver donor (OLD, age ≥70) graft offers are frequently declined, with utilization worsening over the last decade. To understand how offer acceptance varies by center, we studied 1113 eventually transplanted OLD grafts from 2009 to 2017 using Scientific Registry of Transplant Recipients (SRTR) data and random-intercept multilevel logistic regression. To understand how center-level acceptance of OLD graft offers might be associated with waitlist and posttransplant outcomes, we studied all adult, actively listed, liver-only candidates and recipients during the study period using Poisson regression (transplant rate), competing risks regression (waitlist mortality), and Cox regression (posttransplant mortality). Among 117 centers, OLD offer acceptance ranged from 0 (23 centers) to 95 acceptances, with a median odds ratio of 2.88. Thus, a candidate may be three times as likely to receive an OLD graft simply by listing at a different center. Centers in the highest quartile (Q4) of OLD acceptance (accepted 39% of OLD offers) accepted more nationally shared organs (Q4 versus Q1: 14.1% versus 0.0%, P < 0.001) and had higher annual liver transplant volume (Q4 versus Q1: 80 versus 21, P < 0.001). After adjustment, nationally shared OLD offers (adjusted odds ratio [aOR]: 0.16, 95% confidence interval [CI]: 0.13-0.20) and offers to centers with higher median Model for End-Stage Liver Disease (MELD) at transplant (aOR: 0.74, 95% CI: 0.62-0.87) were less likely to be accepted. OLD offers to centers with higher annual transplant volume were more likely to be accepted (aOR: 1.21, 95% CI: 1.14-1.30). Additionally, candidates listed at centers within the highest quartile of OLD graft offer acceptance had higher deceased donor liver transplantation (DDLT) rates (adjusted incidence rate ratio: 1.45, 95% CI: 1.41-1.50), lower waitlist mortality (adjusted subhazard ratio: 0.76, 95% CI: 0.72-0.76), and similar posttransplant survival (adjusted hazard ratio: 0.93, 95% CI: 0.86-1.01) when compared with those listed at centers in the lowest quartile of OLD graft offer acceptance. The wide variation in OLD offer acceptance supports the need for optimizing the organ offer process and efficiently directing OLD offers to centers more likely to use them.

BACKGROUND:Historically, donation after circulatory death (DCD) livers were frequently discarded due to higher mortality and graft loss after liver transplantation (LT). However, the demand for liver transplantation continues to outstrip the supply of "acceptable" organs. Additionally, changes in the donor pool, organ allocation, clinical management of donors and recipients, and improved clinical protocols might have altered post-DCD-LT outcomes. METHODS:We studied 5,975 recovered DCD livers using U.S. SRTR data from 2005-2017, with a comparison group of 78,235 adult DBD livers recovered during the same time period. We quantified temporal trends in discard using adjusted multilevel logistic regression and temporal trends in post-LT mortality and graft loss for DCD LT recipients using adjusted Cox regression. RESULTS:DCD livers were more likely to be discarded than DBD livers across the entire study period, and the relative likelihood of discard increased over time (adjusted odds ratio [aOR] of discard DCD vs. DBD 3.854.455.14 2005-2007, 5.225.876.59 2015-2017) despite improving outcomes after DCD LT. Mortality risk for DCD LTs decreased in each time period (compared to 2005-2007, aHR 2008-2011 0.720.840.97, aHR 2012-2014 0.480.580.70, aHR 2015-2017 0.340.430.55), as did risk of graft loss (compared to 2005-2007, aHR 2008-2011 0.690.810.94, aHR 2012-2014 0.450.550.67, aHR 2015-2017 0.360.450.56). CONCLUSIONS:Despite dramatic improvements in outcomes of DCD LT recipients, DCD livers remain substantially more likely to be discarded than DBD livers, and this discrepancy has actually increased over time. DCD livers are underutilized and have the potential to expand the donor pool.

BACKGROUND:Early steroid withdrawal (ESW) is a viable maintenance immunosuppression strategy in low-risk kidney transplant recipients. A low panel reactive antibody (PRA) may indicate low-risk condition amenable to ESW. We aimed to identify the threshold value of PRA above which ESW may pose additional risk, and to compare the association of ESW with transplant outcomes across PRA strata. METHODS:We studied 121,699 deceased-donor kidney-only recipients in 2002-2017 from SRTR. Using natural splines and ESW-PRA interaction terms, we explored how the associations of ESW with transplant outcomes change with increasing PRA values, and identified a threshold value for PRA. Then, we assessed whether PRA exceeding the threshold modified the associations of ESW with 1-year acute rejection, death-censored graft failure, and death. RESULTS:The association of ESW with acute rejection exacerbated rapidly when PRA exceeded 60. Among PRA≤60 recipients, ESW was associated with a minor increase in rejection (aOR=1.001.051.10) and with a tendency of decreased graft failure (aHR=0.910.971.03). However, among PRA>60 recipients, ESW was associated with a substantial increase in rejection (aOR=1.191.271.36; interaction p<0.001) and with a tendency of increased graft failure (aHR=0.981.081.20; interaction p=0.028). The association of ESW with death was similar between PRA strata (PRA≤60, aHR=0.910.961.01; and PRA>60, aHR=0.900.991.09; interaction p=0.5). CONCLUSIONS:Our findings show that the association of ESW with transplant outcomes is less favorable in recipients with higher PRA, especially those with PRA>60, suggesting a possible role of PRA in the risk assessment for ESW.