Faculty Bibliography

Status 1A liver transplant candidates are given the highest medical priority for the allocation of deceased donor livers. Organ Procurement and Transplantation Network (OPTN) policy requires physicians to certify that a candidate has a life expectancy without a transplant of less than 7 days for that candidate to be given status 1A. Additionally, candidates receiving status 1A must have one of six medical conditions listed in policy. Using Scientific Registry of Transplant Recipients data from all prevalent liver transplant candidates from 2010 to 2020, we used a bias-corrected Kaplan-Meier model to calculate the survival of status 1A candidates and to determine their life expectancy without a transplant. We found that status 1A candidates have a life expectancy without a transplant of 24 (95% CI 20-46) days-over three times longer than what policy requires for status 1A designation. We repeated the analysis for subgroups of status 1A candidates based on the medical conditions that grant status 1A. We found that none of these subgroups met the life expectancy requirement. Harmonizing OPTN policy with observed data would sustain the integrity of the allocation process.

Acuity circles (AC), the new liver allocation system, was implemented on February 4, 2020. Difference-in-differences analyses estimated the effect of AC on adjusted deceased donor transplant and offer rates across Pediatric End-Stage Liver Disease (PELD) and Model for End-Stage Liver Disease (MELD) categories and types of exception statuses. The offer rates were the number of first offers, top 5 offers, and top 10 offers on the match run per person-year. Each analysis adjusted for candidate characteristics and only used active candidate time on the waiting list. The before-AC period was February 4, 2019, to February 3, 2020, and the after-AC period was February 4, 2020, to February 3, 2021. Candidates with PELD/MELD scores 29 to 32 and PELD/MELD scores 33 to 36 had higher transplant rates than candidates with PELD/MELD scores 15 to 28 after AC compared with before AC (transplant rate ratios: PELD/MELD scores 29-32, _2.34 3.32_4.71 ; PELD/MELD scores 33-36, _1.70 2.51_3.71 ). Candidates with PELD/MELD scores 29 or higher had higher offer rates than candidates with PELD/MELD scores 15 to 28, and candidates with PELD/MELD scores 29 to 32 had the largest difference (offer rate ratios [ORR]: first offers, _2.77 3.95_5.63 ; top 5 offers, _3.90 4.39_4.95 ; top 10 offers, _4.85 5.30_5.80 ). Candidates with exceptions had lower offer rates than candidates without exceptions for offers in the top 5 (ORR: hepatocellular carcinoma [HCC], _0.68 0.77_0.88 ; non-HCC, _0.73 0.81_0.89 ) and top 10 (ORR: HCC, _0.59 0.65_0.71 ; non-HCC, _0.69 0.75_0.81 ). Recipients with PELD/MELD scores 15 to 28 and an HCC exception received a larger proportion of donation after circulatory death (DCD) donors after AC than before AC, although the differences in the liver donor risk index were comparatively small. Thus, candidates with PELD/MELD scores 29 to 34 and no exceptions had better access to transplant after AC, and donor quality did not notably change beyond the proportion of DCD donors.

Increasing numbers of compatible pairs are choosing to enter paired exchange programs, but motivations, outcomes, and system-level effects of participation are not well described. Using a linkage of the Scientific Registry of Transplant Recipients and National Kidney Registry, we compared outcomes of traditional (originally incompatible) recipients to originally compatible recipients using the Kaplan-Meier method. We identified 154 compatible pairs. Most pairs sought to improve HLA matching. Compared to the original donor, actual donors were younger (39 vs. 50 years, p < .001), less often female (52% vs. 68%, p < .01), higher BMI (27 vs. 25 kg/m², p = .03), less frequently blood type O (36% vs. 80%, p < .001), and had higher eGFR (99 vs. 94 ml/min/1.73 m², p = .02), with a better LKDPI (median 7 vs. 22, p < .001). We observed no differences in graft failure or mortality. Compatible pairs made 280 additional transplants possible, many in highly sensitized recipients with long wait times. Compatible pair recipients derived several benefits from paired exchange, including better donor quality. Living donor pairs should receive counseling regarding all options available, including kidney paired donation. As more compatible pairs choose to enter exchange programs, consideration should be given to optimizing compatible pair and hard-to-transplant recipient outcomes.

BACKGROUND:In older adults (≥65) access to and outcomes following kidney transplantation (KT) have improved over the past three decades. It is unknown if there were parallel trends in re-KT. We characterized the trends, changing landscape, and outcomes of re-KT in older adults. METHODS:Among the 44,149 older kidney-only recipients (1995-2016) in the Scientific Registry of Transplant Recipients, we identified 1,743 who underwent re-KT. We analyzed trends and outcomes (mortality, death-censored graft failure [DCGF]) by eras (1995-2002, 2003-2014 and 2015-2016) that were defined by changes to the ECD and KDPI policies. RESULTS:Among all older kidney-only recipients during 1995-2002, 2003-2014, 2015-2016 the proportion that were re-KTs increased from 2.7%-4.2%-5.7% p<0.001, respectively. Median age at re-KT (67-68-68, p=0.04), years on dialysis after graft failure (1.4-1.5-2.2, p=0.003), donor age (40.0-43.0-43.5, p=0.04), proportion with PRA 80-100 (22.0%-32.7%-48.7%, p<0.001) and donations after circulatory death (1.1%-13.4%-19.5%, p<0.001) have increased. Despite this, the 3-year cumulative incidence for mortality (22.3%-19.1%-11.5%, p=0.002) and DCGF (13.3%-10.0%-5.1%, p=0.01) decreased over time. Compared with deceased donor re-transplant recipients during 1995-2002, those during 2003-2014 and 2015-2016 had lower mortality hazard (aHR=0.78, 95%CI:0.63-0.86 and aHR=0.55, 95%CI:0.35-0.86, respectively). These declines were noted but not significant for DCGF and in living donor re-KTs. CONCLUSIONS:In older re-transplant recipients, outcomes have improved significantly over time despite higher risk profiles; yet they represent a fraction of the KTs performed. Our results support increasing access to re-KT in older adults; however, approaches to guide the selection and management in those with graft failure need to be explored.