Kidney, pancreas and liver allocation and distribution in the United States

Retrospective Analysis of the Impact of High- and Low-Quality Donor Livers for Patients with High-Acuity Illness

BACKGROUND Patients with high-acuity liver failure have increased access to marginal and split liver options, owing to historically high waitlist mortality rates. While most research states that donor liver quality has no impact on patients with high-acuity illness, there have been inconsistencies in recent research on how liver quality impacts post-transplant outcomes for these patients. We aimed to quantify donor liver quality with various post-transplantation patient outcomes for patients with high-acuity illness. MATERIAL AND METHODS Using the liver donor risk index (LDRI), model for end stage liver disease (MELD), and clinically relevant recipient factors, we used multivariate logistic regression to analyze how donor liver quality affects varying measures of patient outcomes for 9923 high-acuity patients from June 18, 2013, to June 18, 2022. RESULTS Using LDRI, high-quality livers had a significant protective impact on high-acuity patient mortality, compared with low-quality livers (OR=0.695 [0.549, 0.879], P=0.002). High-quality livers also had significant impact on graft survival (OR=0.706 [0.558, 0.894], P=0.004). Two sensitivity patient mortality analyses, excluding patients with status 1A and hepatocellular carcinoma, showed significant protective findings for high-quality livers. High-quality livers had insignificant outcomes on long-term survivor mortality, length of hospitalization, and primary non-function outcomes, compared with low-quality donor livers. CONCLUSIONS While our findings suggest donor quality has an impact on high-acuity patient outcomes, these findings indicate further research is needed in intent-to-treat analysis on clinical offer data to provide a clearer finding of how donor quality affects patients with high-acuity illness.

A modified Kidney Donor Risk Index for pediatric kidney transplant recipients

BACKGROUND

The Kidney Donor Risk Index (KDRI) by Rao et al. was developed to measure the quality of kidney allografts. While Rao's KDRI has been found to be a robust measure of kidney allograft survival for adult kidney transplant recipients, many studies have indicated the need to create a distinct pediatric KDRI.

METHODS

Our retrospective study utilized data from the United Network for Organ Sharing database. We examined 9295 deceased donor recipients' data for age < 18 years from 1990 to 2020. We performed a multivariate Cox regression to determine the significant recipient and transplant factors impacting pediatric kidney allograft survival.

RESULTS

Multivariate analysis found 5 donor factors to be independently associated with graft failure or recipient death: age, female sex, anoxia as the cause of death, history of cigarette use, and cold ischemia time. Using receiver operator characteristic (ROC) curve analysis and analyzing the predictive value of each KDRI at 1, 5, and 10 years, the proposed pediatric KDRI had a statistically significant and higher predictive value for pediatric recipients at 5 (0.60 versus 0.57) and 10 years (0.61 versus 0.57) than the Rao KDRI.

CONCLUSIONS

The proposed pediatric KDRI may provide a more accurate and simpler index to assess the quality of kidney allografts for pediatric recipients. However, due to the mild increase in predictive capabilities over the Rao index, the study serves as a proof of concept to develop a pediatric KDRI. Further studies should focus on increasing the index's predictive capabilities. A higher resolution version of the Graphical abstract is available as Supplementary information.

Deceased donor organ allocation in pediatric transplantation: A historical narrative

BACKGROUND

Since the earliest clinical successes in solid organ transplantation, the proper method of organ allocation for children has been a contentious subject. Over the past 30-35 years, the medical and social establishments of various countries have favored some degree of preference for children on the respective waiting lists. However, the specific policies to accomplish this have varied widely and changed frequently between organ type and country.

METHODS

Organ allocation policies over time were examined. This review traces the reasons behind and the measures/principles put in place to promote early deceased donor transplantation in children.

RESULTS

Preferred allocation in children has been approached in a variety of ways and with varying degrees of commitment in different solid organ transplant disciplines and national medical systems.

CONCLUSION

The success of policies to advantage children has varied significantly by both organ and medical system. Further work is needed to optimize allocation strategies for pediatric candidates.

Organ allocation in pediatric abdominal transplant

Pediatric patients constitute an important group within the general transplant population, given the opportunity to significantly extend their lives with successful transplantation. Children have historically received special consideration under the various abdominal solid organ allocation algorithms, but matching patients with size and weight restrictions with appropriate donors remains an ongoing issue. Here, we describe the historical trends in pediatric organ allocation policies for liver, kidney, intestine, and pancreas transplantation. We also review recent changes to these allocation policies, with particular attention to recent amendments to geographical prioritization, with the dissolution of donor service areas and United Network for Organ Sharing (UNOS) regions and the subsequent creation of acuity circles.

Evolving Trends in Risk Profiles and Outcomes in Older Adults Undergoing Kidney Retransplantation

BACKGROUND

In older adults (≥65), access to and outcomes following kidney transplantation (KT) have improved over the past 3 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 1743 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 expanded criteria donors and Kidney Donor Profile Index 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% to 4.2% to 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 panel reactive antibody 80-100 (22.0%-32.7%-48.7%, P < 0.001), and donation after circulatory death (1.1%-13.4%-19.5%, P < 0.001) have increased. Despite this, the 3-y 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 retransplant recipients during 1995-2002, those during 2003-2014 and 2015-2016 had lower mortality hazard (aHR = 0.78, 95% confidence interval, 0.63-0.86 and aHR = 0.55, 95% confidence interval, 0.35-0.86, respectively). These declines were noted but not significant for DCGF and in living donor re-KTs.

CONCLUSIONS

In older retransplant 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.

Technology-Enabled Care and Artificial Intelligence in Kidney Transplantation

Purpose of Review

Artificial intelligence (AI), machine learning, and technology-enabled remote patient care have evolved rapidly and have now been incorporated into many aspects of medical care. Transplantation is fortunate to have large data sets upon which machine learning algorithms can be constructed. AI are now available to improve pretransplant management, donor selection, and post-operative management of transplant patients.

Recent Findings

Changes in patient and donor characteristics warrant new approaches to listing and organ acceptance practices. Machine learning has been employed to optimize donor selection to identify patients likely to benefit from transplantation of higher risk organs, increasing organ discard and reducing waitlist mortality. These models have greater precisions and predictive ability than currently employed metrics including the Kidney Donor Profile Index and the expected posttransplant survival models. After transplant, AI tools have been developed to optimize immunosuppression management, track patients adherence, and assess graft survival.

Summary

AI and technology-enabled management tools are now available throughout the transplant journey. Unfortunately, those are frequently not available at the point of decision (patient listing, organ acceptance, posttransplant clinic), limiting utilization. Incorporation of these tools into the EMR, the Donor Net® organ offer system, and mobile devices is vital to ensure widespread adoption.

Mortality and Access to Kidney Transplantation in Patients with Sickle Cell Disease-Associated Kidney Failure

BACKGROUND AND OBJECTIVES

Patients with sickle cell disease-associated kidney failure have high mortality, which might be lowered by kidney transplantation. However, because they show higher post-transplant mortality compared with patients with other kidney failure etiologies, kidney transplantation remains controversial in this population, potentially limiting their chance of receiving transplantation. We aimed to quantify the decrease in mortality associated with transplantation in this population and determine the chance of receiving transplantation with sickle cell disease as the cause of kidney failure as compared with other etiologies of kidney failure.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using a national registry, we studied all adults with kidney failure who began maintenance dialysis or were added to the kidney transplant waiting list in 1998-2017. To quantify the decrease in mortality associated with transplantation, we measured the absolute risk difference and hazard ratio for mortality in matched pairs of transplant recipients versus waitlisted candidates in the sickle cell and control groups. To compare the chance of receiving transplantation, we estimated hazard ratios for receiving transplantation in the sickle cell and control groups, treating death as a competing risk.

RESULTS

Compared with their matched waitlisted candidates, 189 transplant recipients with sickle cell disease and 220,251 control recipients showed significantly lower mortality. The absolute risk difference at 10 years post-transplant was 20.3 (98.75% confidence interval, 0.9 to 39.8) and 19.8 (98.75% confidence interval, 19.2 to 20.4) percentage points in the sickle cell and control groups, respectively. The hazard ratio was also similar in the sickle cell (0.57; 95% confidence interval, 0.36 to 0.91) and control (0.54; 95% confidence interval, 0.53 to 0.55) groups (interaction P=0.8). Nonetheless, the sickle cell group was less likely to receive transplantation than the controls (subdistribution hazard ratio, 0.73; 95% confidence interval, 0.61 to 0.87). Similar disparities were found among waitlisted candidates (subdistribution hazard ratio, 0.62; 95% confidence interval, 0.53 to 0.72).

CONCLUSIONS

Patients with sickle cell disease-associated kidney failure exhibited similar decreases in mortality associated with kidney transplantation as compared with those with other kidney failure etiologies. Nonetheless, the sickle cell population was less likely to receive transplantation, even after waitlist registration.

Cytomegalovirus serologic matching in deceased donor kidney allocation optimizes high- and low-risk (D+R- and D-R-) profiles and does not adversely affect transplant rates

Cytomegalovirus (CMV) is a major cause of infection-related morbidity and mortality in kidney transplantation. The most significant risk for developing CMV infection after transplant depends upon donor (D) and recipient (R) CMV serostatus. In 2012, our Organ Procurement Organization (OPO) began a novel pretransplant CMV prevention strategy via matching deceased kidney donors and recipients by CMV serostatus. Prior to the matching protocol, our distribution of seropositive and seronegative donors and recipients was similar to the United States at large. After the matching protocol, high-risk D+R- were reduced from 18.5% to 2.9%, whereas low-risk D-R- were increased from 13.5% to 24%. There was no adverse effect on transplant rates and no differential effect on waiting times for R+ vs R- after the protocol was implemented. This protocol could be implemented on a regional or national level to optimize low and high-risk CMV seroprofiles and potentially improve CMV-related outcomes in kidney transplantation.

Outcomes of kidney transplantation from elderly deceased donors of a Korean registry

To overcome organ shortage, expanded criteria donors, including elderly deceased donors (DDs), should be considered. We analyzed outcomes of kidney transplantation (KT) from elderly DDs in a nationwide study. In total, data of 1049 KTs from DDs using the database of Korean Organ Transplantation Registry (KOTRY) were retrospectively analyzed based on the age of DDs: age ≥60 years vs. <60 years. Clinical information, graft status, and adverse events were reviewed in DDs and recipients. The mean age of the 1006 DDs was 51.04±10.54 years, and 21.5% of donors were aged ≥60 years. Elderly DDs had a significantly higher prevalence of diabetes and hypertension and higher Kidney Donor Risk Index (KDRI) and Kidney Donor Profile Index (KDPI). The mean age of the recipients was 47.45±14.87 years. Patients who received KT from elderly DDs were significantly older (53.12±15.14 vs. 45.88±14.41, P<0.001) and had a higher rate of diabetes (41.9 vs. 24.4%, P<0.001). Graft outcomes were not significantly different. Renal function was similar between the groups at the time of discharge and at 6 months, 1 year, and 2 years after KT. The rate of delayed graft function (DGF) was not significantly different. Risk factors of DGF were significantly different in DDs aged ≥60 years and <60 years. In the multivariable model, male sex (odds ratio: 3.99, 95% confidence interval: 1.42–11.22; P = 0.009) and KDRI (12.17, 2.23–66.34; P = 0.004) were significant risk factors for DGF in DDs aged ≥60 years. In DDs aged <60 years, thymoglobulin induction (2.62, 1.53–4.48; P<0.001) and continuous renal replacement therapy (3.47, 1.52–7.96; P = 0.003) were significant factors. Our data indicated that graft outcomes, including renal function and DGF, were similar for elderly DDs and DDs aged <60 years. Elderly DDs might be considered tolerable donors for KT, with active preoperative surveillance.

Basic principles of liver allocation and development over the years

PURPOSE OF REVIEW

Prior to the enactment of the National Organ Transplant Act in 1984, there was no organized system to allocate donor organs in the United States. The process of liver allocation has come a long way since then, including the development and implementation of the Model for End-stage Liver Disease, which is an objective estimate of risk of mortality among candidates awaiting liver transplantation.

RECENT FINDINGS

The Liver Transplant Community is constantly working to optimize the distribution and allocation of scare organs, which is essential to promote equitable access to a life-saving procedure in the setting of clinical advances in the treatment of liver disease. Over the past 17 years, many changes have been made. Most recently, liver distribution changed such that deceased donor livers will be distributed based on units established by geographic circles around a donor hospital rather than the current policy, which uses donor service areas as the unit of distribution. In addition, a National Liver Review Board was created to standardize the process of determining liver transplant priority for candidates with exceptional medical conditions. The aim of these changes is to allocate and distribute organs in an efficient and equitable fashion.

SUMMARY

The current review provides a historical perspective of liver allocation and the changing landscape in the United States.

Trends in kidney transplant outcomes in children and young adults with cystinosis

Temporal changes in kidney transplant outcomes for cystinosis are unknown. We used the SRTR to identify all kidney transplants performed for cystinosis in patients younger than 31 years between 1987 and 2017. We divided time into three equal eras (1987-1997, 1998-2007, and 2008-2017) to assess changes in outcomes using Cox proportional and linear regression models. We examined 441 transplants in 362 patients. Age at ESRD progressively increased (12.1 vs 13.3 vs 13.4; P = .046). Eras 2 and 3 had lower risk of acute rejection (aHR 2 vs 1:0.45; P < .001) (aHR 3 vs 1:0.26; P < .001) and higher 5-year mean GFR (difference 2 vs 1:9.2 mL/min/1.73 m² ; P = .005) (difference 3 vs 1:12.9 mL/min/1.73 m² ; P = .002) compared with era 1. Five-year graft survival was similar across eras, but 5-year patient survival was higher for era 2 (aHR: 0.25; P = .01). Seventy-nine patients underwent retransplantation. Five-year patient (94.2% vs 92.5%; P = .57) and graft survival (79.1% vs 74.1%; P = .52) were similar between primary and subsequent transplants. Age at ESRD, acute rejection, GFR at 5 years, and patient survival improved over time. Kidney retransplantation is associated with excellent outcomes in children and young adults with cystinosis.

Evaluation of Accepting Kidneys of Varying Quality for Transplantation or Expedited Placement With Decision Trees

BACKGROUND

Underutilization of marginal-quality kidneys for transplantation produced ideas of expediting kidney placement for populations with decreased opportunities of receiving transplants. Such policies can be less efficacious for specific individuals and should be scrutinized until the decision-making for accepting marginal-quality organs, which has relied on experiential judgment, is better understood at the individual level. There exist rigorous tools promoting personalized decisions with useful and objective information.

METHODS

This article introduces a decision-tree methodology that analyzes a patient's dilemma: to accept a kidney offer now or reject it. The methodology calculates the survival benefit of accepting a kidney given a certain quality now and the survival benefit of rejecting it. Survival benefit calculation accounts for patients' and donors' characteristics and transplant centers' and organ procurement organizations' performances and incorporates patients' perceived transplant and dialysis utilities. Valuations of rejecting an offer are contingent on future opportunities and subject to uncertainty in the timing of successive kidney offers and their quality and donor characteristics.

RESULTS

The decision tree was applied to a realistic patient profile as a demonstration. The tool was tested on 1000 deceased-donor kidney offers in 2016. Evaluating up to 1 year of future offers, the tool attains 61% accuracy, with transplant utility of 1.0 and dialysis utility of 0.5. The accuracy reveals potential bias in kidney offer acceptance/rejection at transplant centers.

CONCLUSIONS

The decision-tree tool presented could aid personalized transplant decision-making in the future by providing patients with calculated, individualized survival benefits between accepting and rejecting a kidney offer.

How Inaccurate Metrics Hide the True Potential for Organ Donation in the United States

BACKGROUND

There is a discrepancy between the reported increase in donor conversion rates and the number of organs available for transplant.

METHODS

Secondary analysis of data obtained from the Scientific Registry of Transplant Recipients from January 2003 through December 2015 was performed. The primary outcomes were the (1) number of brain-dead donors from whom solid organs were recovered and (2) number of the organs transplanted. Descriptive statistics and growth plots were used to examine the trajectory of organ donation, recovery, and transplantation outcomes over the 11-year period.

RESULTS

From 2003 to 2006, the number of brain-dead donors increased from 6187 to 7375, remaining relatively stable at approximately 7200 thereafter. The average eligible deaths per organ procurement organization dropped from 182.7 (standard deviation [SD]: 131.3) in 2003 to 149.3 (SD: 111.4) in 2015. This suggests a total of 12 493 unrealized potential donors (2006-2015).

CONCLUSIONS

Since 2006, a steady decline in the number of donor-eligible deaths was reported. In 2003, the reported eligible deaths was 11 326. This number peaked in 2004 at 11 346, tumbling to 9781 eligible donors in 2015, despite a 9% increase in the US population. From 2006 to 2015, the data indicate an artificial depression and underestimation of the true potential of brain-dead donors in the United States of conservatively 12 493 donors or 39 728 missing organs. New metrics providing objective but verifiable counts of the donor pool are needed.

Renal allograft loss due to renal vascular thrombosis in the US pediatric renal transplantation

BACKGROUND

Renal vascular thrombosis (RVT) is a major cause of early allograft loss in the first year following pediatric kidney transplantation. We examined recent trends in allograft loss due to RVT and identified associated risk factors.

METHODS

We identified 14,640 kidney-only transplants performed between 1995 and 2014 with follow-up until June 30, 2016, in 13,758 pediatric patients aged < 19 years from the US Renal Data System. We examined the 1-year incidence of allograft loss due to RVT by year of transplant, and plotted the trend over time. Cox proportional hazards models were used to investigate the relationship between year of transplant as well as recipient, donor, and transplant characteristics with allograft loss due to RVT.

RESULTS

The incidence of allograft loss due to RVT consistently declined among pediatric kidney transplant performed between 1995 and 2014. Among transplants performed between 1995 and 2004, 128/7542 (1.7%) allografts were lost due to RVT compared to 53/7098 (0.8%) among transplants performed between 2005 and 2014; average 1-year cumulative incidence was 1.5% (95% CI, 1.3-1.9%) and 0.6% (95% CI, 0.5-0.8%), respectively. Increased risk for allograft loss due to RVT was associated with en bloc kidney transplantation (HR, 3.42; 95% CI 1.38-8.43) and cold ischemia time ≥ 12 h (HR, 1.78; 95% CI, 1.15-2.76). Interestingly, these risk factors were more prevalent in the latter decade.

CONCLUSIONS

The incidence of allograft loss due to RVT significantly and continuously declined among pediatric kidney transplants performed between 1995 and 2014. The causes for this improvement are unclear in the present analysis.

Histological and clinical evaluation of marginal donor kidneys before transplantation: Which is best?

Organ shortage represents one of the major limitations to the development of kidney transplantation. To increase the donor pool and to answer the ever increasing kidney request, physicians are recurring to marginal kidneys as kidneys from older donors, from hypertensive or diabetic donors and from non-heart beating donors. These kidneys are known to have frequently a worse outcome in the recipients. To date major problem is to evaluate such kidneys in order to use or to discard them before transplantation. The use of such kidneys create other relevant question as whether to use them as single or dual transplant and to allocate them fairly according transplant programs. The pre-transplant histological evaluation, the clinical evaluation of the donor or both the criteria joined has been used and according the time each criterion prevailed over the others. Aim of this review has been to examine the advantages and the drawbacks of any criterion and how they have changed with time. To date any criterion has several limitations and several authors have argued for the development of new guidelines in the field of the kidney evaluation for transplantation. Several authors argue that the use of omic technologies should improve the organ evaluation and studies are ongoing to evaluate these technologies either in the donor urine or in the biopsies taken before transplantation.

Leveraging marginal structural modeling with Cox regression to assess the survival benefit of accepting vs declining kidney allograft offers

Existing studies evaluating the survival benefit of kidney transplantation were unable to incorporate time-updated information on decisions related to each organ offer. We used national registry data, including organ turndown data, to evaluate the survival benefit of accepting vs turning down kidney offers in candidates waitlisted from 2007-2013. Among candidates who declined their first offer, only 43% ultimately received organ transplantations. Recipients who later underwent organ transplantation after declining their first offer had markedly longer wait times than recipients who accepted their first offer, and 56% received kidney transplants that were of similar or lower quality compared to their initial offer. In marginal structural modeling analyses accounting for time-updated offer characteristics (including Kidney Donor Profile Index, Public Health System risk status, and pumping), after 3 months posttransplant, there was a significant survival benefit of accepting an offer (adjusted hazard ratio 0.76, 95% confidence interval 0.66-0.89) that was similar among diabetics, candidates aged >65 years, and candidates living in donor service areas with the longest waitlist times. After carefully accounting for the effect of donor quality, we confirm that the survival benefit of accepting an organ offer is clinically meaningful and persistent beyond 3 months post-kidney transplantation, including high-risk subgroups of organ transplantation candidates.

Association of Kidney Transplant Center Volume With 3-Year Clinical Outcomes

RATIONALE & OBJECTIVE

A robust relationship between procedure volume and clinical outcomes has been demonstrated across many surgical fields. This study assessed whether a center volume-outcome relationship exists for contemporary kidney transplantation, specifically for diabetic recipients, older recipients (aged ≥65 years), and recipients of high kidney donor profile index (KDPI ≥ 85) kidneys.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Adult kidney-only transplant recipients who underwent transplantation between 2009 and 2013 (N = 79,581).

EXPOSURES

The primary exposure variable was center volume, categorized into quartiles based on the total kidney transplantation volume. Quartile 1 (Q1) centers performed a mean of fewer than 66 kidney transplantations per year, whereas Q4 centers performed a mean of more than 196 kidney transplantations per year.

OUTCOMES

All-cause graft failure and mortality within 3 years of transplantation.

ANALYTICAL APPROACH

Multivariable Cox frailty models were used to adjust for donor characteristics, recipient characteristics, and cold ischemia time.

RESULTS

Minor differences in rates of 3-year deceased donor all-cause graft failure across quartiles of center volume were observed (14.9% for Q1 vs 16.7% for Q4), including in subgroups (diabetic recipients, 18.4% for Q1 vs 19.7% for Q4; older recipients, 19.4% for Q1 vs 22.5% for Q4; recipients of high KDPI kidneys, 26.5% for Q1 vs 26.5% for Q4). Results were similar for 3-year mortality. After adjustment for donor, recipient, and graft characteristics using Cox regression, center volume was not significantly associated with all-cause graft failure or mortality within 3 years, except that diabetic recipients at Q3 centers had slightly lower mortality (compared with Q1 centers, adjusted HR of 0.85 [95% CI, 0.73-0.99]).

LIMITATIONS

Potential unmeasured confounding from patient comorbid conditions and organ selection.

CONCLUSIONS

These findings provide little evidence that care in higher volume centers is associated with better adjusted outcomes for kidney transplant recipients, even in populations anticipated to be at increased risk for graft failure or death.

Accuracy of the Pediatric End-stage Liver Disease Score in Estimating Pretransplant Mortality Among Pediatric Liver Transplant Candidates

IMPORTANCE

Fair allocation of livers between pediatric and adult recipients is critically dependent on the accuracy of mortality estimates afforded by the Pediatric End-stage Liver Disease (PELD) and Model for End-stage Liver Disease, respectively. Widespread reliance on exceptions for pediatric recipients suggests that the 2 systems may not be comparable.

OBJECTIVE

To evaluate the accuracy of the PELD score in estimating 90-day pretransplant mortality among pediatric patients on the United Network for Organ Sharing (UNOS) waiting list.

DESIGN, SETTING, AND PARTICIPANTS

Patients who were listed from February 27, 2002, to March 31, 2014, for primary liver transplant were included in this retrospective analysis and were followed up for at least 2 years through June 17, 2016. The study analyzed 2 cohorts using the UNOS Standard Transplant Analysis and Research data files. The full cohort comprised 4298 patients (<18 years of age) who had chronic liver disease (excluding cancer). The reduced cohort (n = 2421) excluded patients receiving living donor transplantation or PELD exception points.

MAIN OUTCOMES AND MEASURES

Observed and expected 90-day pretransplant mortality rates evaluated at 10-point interval PELD levels.

RESULTS

Among the 4298 patients in the full cohort (mean [SD] age, 2.5 [4.2] years; 2251 [52.4%] female; 2201 [51.2%] white), PELD scores and mortality were concordant (C statistic, 0.8387 [95% CI, 0.8191-0.8584] for the full cohort and 0.8123 [95% CI, 0.7919-0.8327] for the reduced cohort). However, the estimated 90-day mortality using the PELD score underestimated the actual probability of death by as much as 17%.

CONCLUSIONS AND RELEVANCE

With use of the PELD score, the ranking of risk among children was preserved, but direct comparisons between adult and pediatric candidates were not accurate. Children with chronic liver disease who are in need of transplant may be at a disadvantage compared with adults in a similar situation.

Predictive Utility of Lung Allocation Score for Retransplantation Outcomes

BACKGROUND

Treatment of primary graft failure after lung transplantation (LTx) may include retransplantation (rLTx). The number of rLTx cases has doubled since implementation of the Lung Allocation Score in 2005. The Lung Allocation Score was intended to predict LTx outcomes, but its predictive utility has not been assessed in rLTx. We investigated whether 1-year outcomes of LTx and rLTX were equally well predicted by the Lung Allocation Score.

METHODS

Recipients of LTx and rLTx aged 18 years or more were identified in 2005 to 2015 United Network for Organ Sharing data. The Lung Allocation Score was entered in multivariable logistic regression models of 1-year retransplant-free survival. Areas under the receiver-operating characteristics curve summarized model predictive value. We examined whether the Lung Allocation Score and its components were differentially associated with outcomes of LTx and rLTx.

RESULTS

There were 16,837 LTx and 765 rLTx cases meeting inclusion criteria. Crude 1-year retransplant-free survival rates were 86% after LTx compared with 74% after rLTx. On univariate analysis, both LTx and rLTx cohorts showed poor predictive utility of the Lung Allocation Score (area under the curve 0.55 and 0.57, respectively; difference by transplant type, p = 0.307). Neither the Lung Allocation Score nor its components was differentially associated with LTx compared with rLTx outcomes.

CONCLUSIONS

The Lung Allocation Score achieved comparable, but poor, predictive utility for 1-year outcomes of primary LTx and rLTx. We found no evidence that Lung Allocation Score components should be weighted differently for rLTx candidates.

Mortality in Living Kidney Donors With ESRD: A Propensity Score Analysis Using the United States Renal Data System

Introduction

In recent years, data have emerged on the outcomes of living kidney donors who develop end-stage renal disease (ESRD). We aimed to evaluate mortality rates in kidney donors who had initiated dialysis compared with a propensity-matched cohort of dialysis patients without previous kidney donation.

Methods

We used the United States Renal Data System (USRDS) and abstracted 274 previous living kidney donors between 1995 and 2009. There were 609,398 individuals on dialysis without kidney donation. We used propensity score matching to identify 258 donors and 258 nondonors. The time-dependent Cox proportional hazards model was used to compare survival between the 2 matched cohorts.

Results

In the propensity score−matched cohort, mortality was lower in donors compared with nondonors (19% vs. 49%; P < 0.0001). The time-dependent Cox proportional hazards model demonstrated that donors had significantly lower mortality compared with nondonors 0 to 5 years since start of dialysis (hazard ratio [HR]: 0.17; 95% confidence interval [CI] 0.11−0.27; P < 0.0001) and with nondonors 5 to 10 years on dialysis (HR: 0.34; 95% CI: 0.19−0.63; P < 0.001). We were unable to estimate the difference between the 2 groups after 10 years on dialysis with any precision (HR: 0.51; 95% CI: 0.18−1.42; P = 0.20) due to the small sample size.

Conclusion

We observed a lower mortality rate in living kidney donors with ESRD compared with matched nondonors. This data should guide clinicians in the informed consent process with prospective donors.

Evolving Trends in Racial Disparities for Peri-Operative Outcomes with the New Kidney Allocation System (KAS) Implementation

INTRODUCTION

To improve kidney transplant allocation equitability, a new Kidney Allocation System (KAS) was implemented December 4, 2014. The purpose of this study was to determine if the impact of KAS on peri-operative outcomes differed by recipient race/ethnicity.

METHODS

This was a time series analysis using data aggregated in monthly intervals from October 2012 through September 2015 using the University HealthSystem Consortium (UHC). This includes national data aggregated at the center level of all US kidney transplant centers that participate in the UHC (416 centers). Segmented regression with interaction terms was used to determine the impact of KAS on outcomes and differences by race/ethnicity.

RESULTS

A total of 28,809 deceased donor kidney transplants were included with 25 months of pre-KAS data and 10 months of post-KAS data. After KAS implementation, the estimated transplant rate per month decreased significantly for Caucasians by 17.6 cases per month (p = 0.0001), and increased significantly for AAs by 37.8 (p = 0.0001), Hispanics by 16.3 (p = 0.0001), and other races by 8.2 cases per month (p = 0.0001). Delayed graft function, 7- and 14-day readmissions significantly increased after KAS, which did not differ by race. Hispanics saw a 7.7% decrease in ICU admissions after KAS, which differed as compared to other racial/ethnic cohorts (p = 0.0026). Costs of kidney transplantation increased significantly after KAS in all groups except Hispanics. Mortality, length of stay, in-hospital complications, and 30-day readmissions were not significantly impacted by KAS, also not differing by race/ethnicity.

CONCLUSION

KAS had substantial impact on transplant rates by race/ethnicity. KAS also led to increased costs, readmissions, and delayed graft function (DGF) across all racial/ethnic groups. The impact of KAS on ICU cases solely within Hispanics requires further investigation into potential etiologies.

Swaps and Chains and Vouchers, Oh My!: Evaluating How Saving More Lives Impacts the Equitable Allocation of Live Donor Kidneys

Live kidney donation involves a delicate balance between saving the most lives possible and maintaining a transplant system that is fair to the many thousands of patients on the transplant waiting list. Federal law and regulations require that kidney allocation be equitable, but the pressure to save patients subject to ever-lengthening waiting times for a transplant has been swinging the balance toward optimizing utility at the expense of justice. This article traces the progression of innovations created to make optimum use of a patient's own live donors. It starts with the simplest - direct donation by family members - and ends with voucher donations, a very recent and unique innovation because the donor can donate 20 or more years before the intended recipient is expected to need a kidney. In return for the donation, the intended recipient receives a voucher that can be redeemed for a live kidney when it is needed. Other innovations that are discussed include kidney exchanges and list paired donation, which are used to facilitate donor swaps when donor/recipient pairs have incompatible blood types. The discussion of each new innovation shows how the equity issues build on each other and how, with each new innovation, it becomes progressively harder to find an acceptable balance between utility and justice. The article culminates with an analysis of two recent allocation methods that have the potential to save many additional lives, but also affirmatively harm some patients on the deceased donor waiting list by increasing their waiting time for a life-saving kidney. The article concludes that saving additional lives does not justify harming patients on the waiting list unless that harm can be minimized. It also proposes solutions to minimize the harm so these new innovations can equitably perform their intended function of stimulating additional transplants and extending the lives of many transplant patients.

Kidney allograft offers: Predictors of turndown and the impact of late organ acceptance on allograft survival

There is growing interest in understanding patterns of organ acceptance and reducing discard. Little is known about how donor factors, timing of procurement, and geographic location affect organ offer decisions. We performed a retrospective cohort study of 47 563 deceased donor kidney match-runs from 2007 to 2013. Several characteristics unrelated to allograft quality were independently associated with later acceptance in the match-run: Public Health Service increased-risk donor status (adjusted odds ratio [aOR] 2.49, 95% confidence interval [CI] 2.29-2.69), holiday or weekend procurement (aOR 1.11, 95% CI 1.07-1.16), shorter donor stature (aOR 1.53 for <150 cm vs reference >180 cm, 95% CI 1.28-1.94), and procurement in an area with higher intensity of market competition (aOR 1.71, 95% CI 1.62-1.78) and with the longest waiting times (aOR 1.41, 95% CI 1.34-1.49). Later acceptance in the match-run was associated with delayed graft function but not all-cause allograft failure (adjusted hazard ratio 1.01, 95% CI 0.96-1.07). Study limitations include a lack of match-run data for discarded organs and the possibility of sequence inaccuracies for some nonlocal matches. Interventions are needed to reduce turndowns of viable organs, especially when decisions are driven by infectious risk, weekend or holiday procurement, geography, or other donor characteristics unrelated to allograft quality.

Long-term effects of pancreas transplant alone on nephropathy in type 1 diabetic patients with optimal renal function

Background

Limited data are available regarding optimal selection criteria for pancreas transplant alone (PTA) to minimize aggravation of diabetic nephropathy.

Methods

A total of 87 type 1 diabetic patients were evaluated before and after PTA at a single center from January, 1999 to December, 2015, together with 87 matched non-transplanted type 1 diabetic subjects who were candidates for PTA to compare deterioration of native kidney function. A total of 163 patients (79 in the transplanted group and 84 in the nontransplanted group) were finally enrolled after excluding nine patients with estimated glomerular filtration rate less than 60 mL/min/1.73 m² and two patients with moderate proteinuria (≥ 1.5 g/day).

Results

A total of seven recipients (8.9%) had end-stage renal disease post-transplant whereas only one patient (1.2%) developed end-stage renal disease in the nontransplanted group during their follow-up period (median 12.0, range 6–96 months) (p = 0.03). Furthermore, a composite of severe renal dysfunction and end-stage renal disease (31.6% vs 2.4%) was significantly higher in the transplanted group (p < 0.001). Multivariate Cox regression analysis revealed that a higher level of tacrolimus at six months post-transplant (HR = 1.648, CI = 1.140–2.385, p = 0.008) was the only significant factor associated with end-stage renal disease.

Conclusions

There is a considerable risk for deterioration of renal function in PTA recipients post-transplant compared with non-transplant diabetic patients. With rather strict selection criteria such as preoperative proteinuria and estimated glomerular filtration rate, PTA should be considered in diabetic patients to minimize post-transplant aggravation of diabetic nephropathy.

Liver biopsy may facilitate pancreatic graft evaluation: Positive association between liver steatosis and pancreatic graft adipose infiltration

OBJECTIVES

The number of pancreatic transplants has decreased in recent years. Pancreatic grafts have been underutilized compared to other solid grafts. One cause of discard is the macroscopic appearance of the pancreas, especially the presence of fatty infiltration. The current research is aimed at understanding any graft-related association between fatty tissue infiltration of the pancreas and liver steatosis.

METHODS

From August 2013 to August 2014, a prospective cross-sectional clinical study using data from 54 multiple deceased donor organs was performed.

RESULTS

Micro- and macroscopic liver steatosis were significantly correlated with the donor body mass index ([BMI]; p=0.029 and p=0.006, respectively). Positive gamma associations between pancreatic and liver macroscopic and microscopic findings (0.98; confidence interval [CI]: 0.95-1 and 0.52; CI 0.04-1, respectively) were observed. Furthermore, comparisons of liver microscopy findings showed significant differences between severe versus absent (p<0.001), severe versus mild (p<0.001), and severe versus moderate classifications (p<0.001). The area under the receiver operating curve was 0.94 for the diagnosis of steatosis by BMI evaluation using a cut-off BMI of 27.5 kg/m2, which yielded 100% sensitivity, 87% specificity, and 100% negative predictive value.

CONCLUSIONS

We observed a positive association of macroscopic and microscopic histopathological findings in steatotic livers with adipose infiltration of pancreatic grafts.

The Past, Present, and Future of HLA Typing in Transplantation

The HLA region is the most polymorphic genes in the human genome and is associated with an increasing number of disease states. Historically, HLA typing methodology has been governed by phenotypic determination. This practice has evolved into the use of molecular methods such as real-time PCR, sequence-specific oligonucleotides, and sequencing-based methods. Numerous studies have identified HLA matching as a key determinate to improve patient outcomes from transplantation. Solid-organ transplants focus on HLA-DRB1 in renal organ allocation while hematopoietic cell transplants focus on HLA-A, -B, -C, -DRB1 matching. The role of HLA typing in the future will be driven by HLA expression, understanding of HLA haplotypes, and rapid HLA typing.

Comparison between liver resection and liver transplantation on outcomes in patients with solitary hepatocellular carcinoma meeting UNOS criteria: a population-based study of the SEER database

Liver resection (LR) and liver transplantation (LT) are potential curative treatment methods for early hepatocellular carcinoma (HCC). However, it is controversial which treatment is more beneficial to patients with solitary HCC meeting the United Network for Organ Sharing (UNOS) criteria (single lesion, diameter≤50mm, no vascular invasion, no extrahepatic metastasis). We retrieved patients with solitary HCC meeting UNOS criteria diagnosed between 2004-2013 from the Surveillance Epidemiology and End Results (SEER) database. Multivariate Cox proportional hazards regression models were used to evaluate the impact of surgery type (LR/LT) on overall survival (OS) and disease-specific survival (DSS) in both the whole study group and subgroups. Our analyses show that LT Patients had significantly superior OS (Adjusted HR (95% CI): 0.39 [0.26-0.59]) and DSS (Adjusted HR (95% CI): 0.19 [0.10-0.35]) than those receiving LR, although compared with the 288 patients receiving LR, the 258 patients receiving LT had younger age, smaller tumor size, and higher fibrosis score (P<0.001). Subgroup analyses identified significant interactions between surgery type (LR/LT) and gender (Male/Female) in both OS (P=0.02) and DSS (P=0.02). Male patients benefit more from LT compared with LR in both OS (Adjusted HR (95% CI): 0.29 [0.18-0.47]) and DSS (Adjusted HR (95% CI): 0.10 [0.05-0.21]), but there is no difference between patients receiving LT and LR in female patients. In conclusion, LT is associated with superior survival than LR in patients with solitary HCC meeting UNOS criteria. Moreover, male patients benefits more from LT than LR, while female patients do not show different outcomes between the two procedures.

Organ allocation and utilization in pediatric transplantation

Pediatric transplant candidates include heart, lung, liver, pancreas, small intestine, and kidney. The purpose of this article is to review the history and current methods for determining priority of the above-mentioned transplantable organs. The methods used by the authors involved the review of historical and current manuscripts and UNOS policy documents. We summarized the findings in order to create a concise review of the current policies and wait times for transplantation in pediatric transplant patients.

Regional Differences in Communication Process and Outcomes of Requests for Solid Organ Donation

Although federal mandate prohibits the allocation of solid organs for transplantation based on "accidents of geography," geographic variation of transplantable organs is well documented. This study explores regional differences in communication in requests for organ donation. Administrative data from nine partnering organ procurement organizations and interview data from 1339 family decision makers (FDMs) were compared across eight geographically distinct US donor service areas (DSAs). Authorization for organ donation ranged from 60.4% to 98.1% across DSAs. FDMs from the three regions with the lowest authorization rates reported the lowest levels of satisfaction with the time spent discussing donation and with the request process, discussion of the least donation-related topics, the highest levels of pressure to donate, and the least comfort with the donation decision. Organ procurement organization region predicted authorization (odds ratios ranged from 8.14 to 0.24), as did time spent discussing donation (OR = 2.11), the number of donation-related topics discussed (OR = 1.14), and requesters' communication skill (OR = 1.14). Standardized training for organ donation request staff is needed to ensure the highest quality communication during requests, optimize rates of family authorization to donation in all regions, and increase the supply of organs available for transplantation.

Preemptive kidney transplantation is associated with survival benefits among pediatric patients with end-stage renal disease

Kidney transplantation is the preferred treatment for pediatric end-stage renal disease (ESRD). Preemptive transplantation avoids the increased morbidity and mortality of dialysis. Yet, previous studies have not demonstrated significant graft or patient survival benefits for children undergoing transplantation preemptively versus nonpreemptively. These previous studies were limited by small samples sizes and low rates of adverse events. Here we compared graft failure and mortality rates using Kaplan-Meier methods and Cox regression among a large national cohort of children with ESRD undergoing preemptive versus nonpreemptive kidney transplantation between 2000 and 2012. Among 7527 pediatric kidney transplant recipients in the United States Renal Data System, 1668 underwent preemptive transplantation. Over a median 4.8 years follow-up, 1314 experienced graft failure, and over a median 5.2 years of follow-up, 334 died. Dialysis exposure versus preemptive transplantation conferred a higher risk of graft failure (hazard ratio 1.32; 95% confidence interval: 1.10-1.56) and a higher risk of death (hazard ratio 1.69; 95% confidence interval: 1.22-2.33) in multivariable analysis. Compared with children undergoing preemptive transplantation, children on dialysis for >1 year had a 52% higher risk of graft failure and those on dialysis >18 months had an 89% higher risk of death, regardless of donor source. Thus, preemptive transplantation is associated with substantial benefits in allograft and patient survival among children with ESRD, particularly when compared with children who receive dialysis for >1 year. These findings support policies to promote early access to transplantation and avoidance of dialysis for children with ESRD whenever feasible.

Risk Factors for the Development of BK Virus Nephropathy in Renal Transplant Recipients

The BK polyoma virus has, in recent years, become a significant cause of renal allograft dysfunction and failure. Among 260 adult kidney transplant recipients, those with biopsy-proven BK virus nephropathy (BKVN) were compared with those without BKVN with regard to gender, age, race, rejection episodes, time on dialysis, number of organs transplanted, HLA match, live donor versus deceased donor, cold ischemia time, delayed graft function, cytomegalovirus (CMV) serostatus of donor and recipient, induction therapy, and maintenance immunosuppression. Episodes of rejection (35.7% of patients with BKVN vs 8.5% of patients without BKVN; P = .01), transplantation of >1 organ (35.7% of patients with BKVN vs 9.0% of patients without BKVN; P = .01), positive CMV serology in both donor and recipient (71.4% of patients with BKVN vs 41.1% of patients without BKVN; P = .03), and a greater cumulative dose of daclizumab use at the time of induction (2.24 ± 0.05 mg/kg in patients with BKVN vs 2.03 ± 0.14 mg/kg in patients without BKVN; P = .04) were statistically significant risk factors for the development of BKVN. Those who developed BKVN received a higher mean cumulative dose of rabbit antithymoglobulin for induction therapy, but that difference failed to achieve statistical significance (P = .07).

Association Between Organ Procurement Organization Social Network Centrality and Kidney Discard and Transplant Outcomes

BACKGROUND

Given growth in kidney transplant waitlists and discard rates, donor kidney acceptance is an important problem. We used network analysis to examine whether organ procurement organization (OPO) network centrality affects discard and outcomes.

METHODS

We identified 106,160 deceased donor kidneys recovered for transplant from 2000 to 2010 in Scientific Registry of Transplant Recipients. We constructed the transplant network by year with each OPO representing a node and each kidney-sharing relationship between OPOs representing a directed tie between nodes. Primary exposures were the number of different OPOs to which an OPO has given a kidney or from which an OPO has received a kidney in year preceding procurement year. Primary outcomes were discard, cold-ischemia time, delayed graft function, and 1-year graft loss. We used multivariable regression, restricting analysis to the 50% of OPOs with highest discard and stratifying remaining OPOs by kidney volume. Models controlled for kidney donor risk index, waitlist time, and kidney pumping.

RESULTS

An increase in one additional OPO to which a kidney was given by a procuring OPO in a year was associated with 1.4% lower likelihood of discard for a given kidney (odds ratio, 0.986; 95% confidence interval, 0.974-0.998) among OPOs procuring high kidney volume, but 2% higher likelihood of discard (odds ratio, 1.021; 95% confidence interval, 1.006-1.037) among OPOs procuring low kidney volume, with mixed associations with recipient outcomes.

CONCLUSIONS

Our study highlights the value of network analysis in revealing how broader kidney sharing is associated with levels of organ acceptance. We conclude interventions to promote broader inter-OPO sharing could be developed to reduce discard for a subset of OPOs.

Allocating Deceased Donor Kidneys to Candidates with High Panel-Reactive Antibodies

BACKGROUND AND OBJECTIVES

In December of 2014, the Organ Procurement and Transplant Network implemented a new Kidney Allocation System (KAS) for deceased donor transplant, with increased priority for highly sensitized candidates (calculated panel-reactive antibody [cPRA] >99%). We used a modified version of the new KAS to address issues of access and equity for these candidates.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a simulation, 10,988 deceased donor kidneys transplanted into waitlisted recipients in 2010 were instead allocated to candidates with cPRA≥80% (n=18,004). Each candidate's unacceptable donor HLA antigens had been entered into the allocation system by the transplant center. In simulated match runs, kidneys were allocated sequentially to adult ABO identical or permissible candidates with cPRA 100%, 99%, 98%, etc. to 80%. Allocations were restricted to donor/recipient pairs with negative virtual crossmatches.

RESULTS

The simulation indicated that 2111 of 10,988 kidneys (19.2%) would have been allocated to patients with cPRA 100% versus 74 of 10,988 (0.7%) that were actually transplanted. Of cPRA 100% candidates, 74% were predicted to be compatible with an average of six deceased donors; the remaining 26% seemed to be incompatible with every deceased donor organ that entered the system. Of kidneys actually allocated to cPRA 100% candidates in 2010, 66% (49 of 74) were six-antigen HLA matched/zero-antigen mismatched (HLA-A, -B, and -DR) with their recipients versus only 11% (237 of 2111) in the simulation. The simulation predicted that 10,356 of 14,433 (72%) candidates with cPRA 90%-100% could be allocated an organ compared with 7.3% who actually underwent transplant.

CONCLUSIONS

Data in this simulation are consistent with early results of the new KAS; specifically, nearly 20% of deceased donor kidneys were (virtually) compatible with cPRA 100% candidates. Although most of these candidates were predicted to be compatible with multiple donors, approximately one-quarter are unlikely to receive a single offer.

Optimizing the utilization of kidneys from small pediatric deceased donors under 15 kg by choosing pediatric recipients

Currently, most kidneys from small pediatric deceased donors are transplanted into adult recipients (i.e., PTA). However, due to the weight mismatch, there is a high discard rate and a high ratio of EBKTs if adopting PTA. Here, we sought both to optimize utilization of these challenging but scarce donor grafts by selecting pediatric recipients and to characterize the feasibility and efficacy of this PTP allocation strategy. From February 2012 to October 2014, kidneys from 27 infant donors ≤ 15 kg were procured and distributed to 38 pediatric candidates in our center. The grafts were utilized for EBKT if the donor weighed 2.5-5 kg and for SKT if the donor weighed 5-15 kg, leading to 10 EBKTs and 28 SKTs. The overall utilization rate from small pediatric deceased donors was 94.12%. After a follow-up of 3-26 months, the graft survival rate was 89.47%, with four graft losses due to vascular thrombosis. Kidneys from low-body-weight donors should be applied to pediatric recipients, and the kidneys from infant donors ≥ 5 kg can be used in single-kidney-transplant procedures at experienced centers to optimize utilization.

Financial Impact of Liver Sharing and Organ Procurement Organizations' Experience With Share 35: Implications for National Broader Sharing

The Share 35 policy for organ allocation, which was adopted in June 2013, allocates livers regionally for candidates with Model for End-Stage Liver Disease scores of 35 or greater. The authors analyzed the costs resulting from the increased movement of allografts related to this new policy. Using a sample of nine organ procurement organizations, representing 17% of the US population and 19% of the deceased donors in 2013, data were obtained on import and export costs before Share 35 implementation (June 15, 2012, to June 14, 2013) and after Share 35 implementation (June 15, 2013, to June 14, 2014). Results showed that liver import rates increased 42%, with an increased cost of 51%, while export rates increased 112%, with an increased cost of 127%. When the costs of importing and exporting allografts were combined, the total change in costs for all nine organ procurement organizations was $11 011 321 after Share 35 implementation. Extrapolating these costs nationally resulted in an increased yearly cost of $68 820 756 by population or $55 056 605 by number of organ donors. Any alternative allocation proposal needs to account for the financial implications to the transplant infrastructure.