The role of bypass filters in deceased donor kidney allocation in the United States

Patient and Provider Attitudes Toward Patient-Facing Kidney Organ Offer Reporting

Introduction

In the United States (US), deceased donor kidney offers are most commonly declined by transplant centers on behalf of waitlisted candidates, without notifying them. We sought to understand patient and provider attitudes toward patient-facing organ offer reporting.

Methods

We conducted a cross-sectional survey of patients, nephrologists, and nephrology social workers on the National Kidney Foundation mailing list and the medical and surgical directors of US kidney transplant programs.

Results

Among 755 patient respondents, 64% wanted to receive organ offer reports. Patients who wanted organ offer information were younger, more likely to be of a non-White race, and more likely to be on dialysis or on the waiting list. Of the patients, 87% reported that centers should be required to tell candidates about the offers they receive, and 62% reported that candidates should be informed after every offer. Among the 107 nephrology respondents, 73% reported that candidates should be provided with organ offer information and 88% reported that they would want to receive a copy of their patients' offer reports. Among 26 transplant program director respondents, 77% reported that candidates should not be notified of offers declined on their behalf. If organ offer reports were required, most program director respondents believed that they should include the reasons offers were declined and should not include offers for kidneys that were ultimately discarded.

Conclusions

Most patients and nephrology providers, but only a minority of transplant program directors, supported the sharing of patient-facing information about individual deceased donor kidney offers that were declined on candidates' behalf.

Decreasing efficiency in deceased donor kidney offer notifications under the new distance-based kidney allocation system

Organ Procurement Organizations (OPOs) recover deceased donor kidneys and place them with matched recipients according to ranked match runs of patients, but offer notification practices differ across the OPOs and have changed following updates to allocation policy (kidney allocation system 250 [KAS250]). This national registry study used batch notification data to quantify time spent on kidney allocation and identify variations in batch notification practices across OPOs before and after the KAS250 allocation system era. Overall allocation time between the first and last offer notifications increased from a median of 1 to 7 hours under the KAS250 allocation system. For match runs of unplaced kidneys, allocation time increased from a median of 18 to 28 hours. Out-of-sequence (OOS) allocation, used by OPOs to limit nonutilization due to excess cold ischemia time, more than doubled in frequency between 2018 and 2022, with median time from first offer to initiation of OOS varying across OPOs from 0 to 47 hours. Increasing rates of organ nonutilization and the observed allocation practice differences based on organ quality demonstrate the urgent need for new approaches to achieve more efficient placement of hard-to-place kidneys. Data-driven approaches to optimize kidney allocation efforts will help ensure fairness in a system that currently allows for wide practice variation and frequent OOS allocation.

The dynamics of deceased donor kidney transplant decision making: insights from studying individual clinicians' offer decisions

Despite the high demand, >7500 recovered kidneys annually go unused, with transplant centers showing significant variation in their offer acceptance practices. However, it remains unclear how much of this variation occurs between individual clinicians within the same center and its impact on allocation efficiency and equity. This study quantified the variability in kidney offer acceptance decisions attributable to clinicians vs centers and examined the role of donor quality in acceptance decisions. We analyzed national transplant registry data (from January 2016 to December 2020) linked to on-call records from 15 transplant centers, creating a clinician-level data set with 344 678 deceased donor kidney offers. The primary outcome was the variability in offer acceptance attributable to clinicians vs centers, quantified via hierarchical, mixed-effect logistic regression models. To complement kidney donor profile index as a measure of donor quality, we incorporated expected acceptance probability, adjusting for a broader set of donor characteristics and recipient factors. Both center-level (0.35; 95% CI: 0.15-0.79) and clinician-level (0.10; 95% CI: 0.06-0.18) variances were significant, with heterogeneity in the kidney donor profile index-acceptance association among clinicians. These results underscore the need for further research into the mechanisms driving the clinician-level variation and its implications for organ allocation efficacy, equity, and patient outcomes.

Variation Across Organ Procurement Organizations in Deceased-Donor Kidney Offer Notification Practices

INTRODUCTION

How offer notifications are distributed early in the kidney allocation timeline, including how widely they are offered, is unclear. A better understanding of offer notification practices across organ procurement organizations (OPOs) may identify opportunities for more efficient allocation.

METHODS

We merged the Scientific Registry of Transplant Recipients potential transplant recipient file with additional offer notification time stamps to identify 54 631 deceased-donor kidney match runs from 2017 to 2023. Offer notifications for a given match run are sent to candidates/centers in "batches." We quantified the number of offers in the initial batch-which theoretically reflects the OPO's initial estimate of how widely a kidney should be offered-and compared this metric across OPOs.

RESULTS

Kidneys were offered to a median of 14 candidates (IQR 9-38) in the first batch of notifications, and this varied across OPOs from 3 to 746 candidates per initial batch. Batch size at the OPO-level did not correlate with rank at kidney placement or OPO nonuse rate. OPOs in the highest quartile of batch size sent more offers (median 100) than presumably necessary to place kidneys (median rank at placement 21), and OPOs in the lowest quartile of batch size sent fewer offers (6) than needed to place kidneys (rank at placement 19).

CONCLUSIONS

Offer notification practices vary widely across OPOs, and many OPOs offer kidneys far more widely than necessary for placement. Optimization of offer notification practices may reduce unnecessary communications. Further research into allocation processes is needed to identify opportunities to improve efficiency of allocation for OPOs and transplant centers.

Short-Term, Mid-Term, and Long-Term Outcomes after Deceased Donor Kidney Transplantation in Patients with AKI: A Systematic Review and Meta-Analysis

Key Points

This study reviews the willingness to use kidneys from donors who have experienced AKI during transplantation and provides a thorough analysis of the existing literature. While delayed graft function is more common, primary nonfunction and acute rejection rates appear comparable, as do allograft function and graft survival compared with non-AKI donor kidneys. Considering the shortage of available organs and the high mortality rate of patients on dialysis, the use of donors with AKI as a source for kidney transplantation is a viable alternative.

Background

AKI is a common complication in hospitalized patients and may occur in potential kidney donors. Observational studies have suggested that kidney transplantation in patients with AKI is feasible and safe, but no systematic evaluation has been performed.

Methods

We performed a systematic review and meta-analysis to evaluate the outcomes of kidney transplantation in patients with AKI. We searched MEDLINE, Embase, Cochrane, Google Scholar, and other databases for studies reporting outcomes of donor kidneys with AKI. We included single-center, multicenter, and registry-based studies and analyzed them according to the definition and severity of AKI. End points were primary and delayed graft function (DGF), primary nonfunction (PNF), length of hospital stay, rejection, graft function, and patient and graft survival at 1, 3, 5, and 8–10 years after transplantation. This study was registered in PROSPERO, number CRD42021260088.

Results

We identified 33 single-center, four multicenter, and seven registry studies with more than 100,000 patients published between 2005 and 2022. Recipients from donors with AKI had a higher risk of DGF (relative risk, 1.51; 95% confidence interval [CI], 1.35 to 1.68). Graft function at discharge was worse in the AKI group (MDCrea [95% CI]: 0.96 mg/dl [0.36 to 1.56, I2=96%], MDGFR [95% CI]: −8.88 ml/min per 1.73 m2 [−15.32 to −2.44, I2=93%]), but improved thereafter and was similar in both groups at 3 months after transplantation (MDCrea [95% CI]: −0.05 mg/dl [−0.18 to 0.07, I2=0%], MDGFR [95% CI]: −1.83 ml/min per 1.73 m2 [−5.29 to 1.63, I2=91%]). Primary nonfunction and patient and graft survival were similar at 1, 3, 5, and 8–10 years after transplantation. There were no differences in rejections regardless of AKI definition and severity.

Conclusions

Transplantation of kidneys with AKI is associated with satisfactory short-term and long-term outcomes and should be pursued to increase the donor pool.

Expanding the access to kidney transplantation: Strategies for kidney transplant programs

Kidney transplantation is the most successful kidney replacement therapy available, resulting in improved recipient survival and societal cost savings. Yet, nearly 70 years after the first successful kidney transplant, there are still numerous barriers and untapped opportunities that constrain the access to transplant. The literature describing these barriers is extensive, but the practices and processes to solve them are less clear. Solutions must be multidisciplinary and be the product of strong partnerships among patients, their networks, health care providers, and transplant programs. Transparency in the referral, evaluation, and listing process as well as organ selection are paramount to build such partnerships. Providing early culturally congruent and patient-centered education as well as maximizing the use of local resources to facilitate the transplant work up should be prioritized. Every opportunity to facilitate pre-emptive kidney transplantation and living donation must be taken. Promoting the use of telemedicine and kidney paired donation as standards of care can positively impact the work up completion and maximize the chances of a living donor kidney transplant.

Increased volume of organ offers and decreased efficiency of kidney placement under circle-based kidney allocation

The newest kidney allocation policy kidney allocation system 250 (KAS250) broadened geographic distribution while increasing allocation system complexity. We studied the volume of kidney offers received by transplant centers and the efficiency of kidney placement since KAS250. We identified deceased-donor kidney offers (N = 907,848; N = 36,226 donors) to 185 US transplant centers from January 1, 2019, to December 31, 2021 (policy implemented March 15, 2021). Each unique donor offered to a center was considered a single offer. We compared the monthly volume of offers received by centers and the number of centers offered before the first acceptance using an interrupted time series approach (pre-/post-KAS250). Post-KAS250, transplant centers received more kidney offers (level change: 32.5 offers/center/mo, P < .001; slope change: 3.9 offers/center/mo, P = .003). The median monthly offer volume post-/pre-KAS250 was 195 (interquartile range 137-253) vs. 115 (76-151). There was no significant increase in deceased-donor transplant volume at the center level after KAS250, and center-specific changes in offer volume did not correlate with changes in transplant volume (r = -0.001). Post-KAS250, the number of centers to whom a kidney was offered before acceptance increased significantly (level change: 1.7 centers/donor, P < .001; slope change: 0.1 centers/donor/mo, P = .014). These findings demonstrate the logistical burden of broader organ sharing, and future allocation policy changes will need to balance equity in transplant access with the operational efficiency of the allocation system.

Characterization of Transplant Center Decisions to Allocate Kidneys to Candidates With Lower Waiting List Priority

Importance

Allocation of deceased donor kidneys is meant to follow a ranked match-run list of eligible candidates, but transplant centers with a 1-to-1 relationship with their local organ procurement organization have full discretion to decline offers for higher-priority candidates and accept them for lower-ranked candidates at their center.

Objective

To describe the practice and frequency of transplant centers placing deceased donor kidneys with candidates who are not the highest rank at their center according to the allocation algorithm.

Design, Setting, and Participants

This retrospective cohort study used 2015 to 2019 organ offer data from US transplant centers with a 1-to-1 relationship with their local organ procurement organization, following candidates for transplant events from January 2015 to December 2019. Participants were deceased kidney donors with a single match-run and at least 1 kidney transplanted locally and adult, first-time, kidney-only transplant candidates receiving at least 1 offer for a locally transplanted deceased donor kidney. Data were analyzed from March 1, 2022 to March 28, 2023.

Exposure

Demographic and clinical characteristics of donors and recipients.

Main Outcomes and Measures

The outcome of interest was kidney transplantation into the highest-priority candidate (defined as transplanted after zero declines for local candidates in the match-run) vs a lower-ranked candidate.

Results

This study assessed 26 579 organ offers from 3136 donors (median [IQR] age, 38 [25-51] years; 2903 [62%] men) to 4668 recipients. Transplant centers skipped their highest-ranked candidate to place kidneys further down the match-run for 3169 kidneys (68%). These kidneys went to a median (IQR) of the fourth- (third- to eighth-) ranked candidate. Higher kidney donor profile index (KDPI; higher score indicates lower quality) kidneys were less likely to go to the highest-ranked candidate, with 24% of kidneys with KDPI of at least 85% going to the top-ranked candidate vs 44% of KDPI 0% to 20% kidneys. When comparing estimated posttransplant survival (EPTS) scores between the skipped candidates and the ultimate recipients, kidneys were placed with recipients with both better and worse EPTS than the skipped candidates, across all KDPI risk groups.

Conclusions and Relevance

In this cohort study of local kidney allocation at isolated transplant centers, we found that centers frequently skipped their highest-priority candidates to place kidneys further down the allocation prioritization list, often citing organ quality concerns but placing kidneys with recipients with both better and worse EPTS with nearly equal frequency. This occurred with limited transparency and highlights the opportunity to improve the matching and offer algorithm to improve allocation efficiency.

Beyond donation to organ utilization in the USA

PURPOSE OF REVIEW

The deceased donor organ pool has broadened beyond young, otherwise healthy head trauma victims. But an abundance of donated organs only benefits patients if they are accepted, expeditiously transported and actually transplanted. This review focuses on postdonation challenges and opportunities to increase the number of transplants through improved organ utilization.

RECENT FINDINGS

We build upon recently proposed changes in terminology for measuring organ utilization. Among organs recovered for transplant, the nonuse rate (NUR REC ) has risen above 25% for kidneys and pancreata. Among donors, the nonuse rate (NUR DON ) has risen to 40% for livers and exceeds 70% for thoracic organs. Programme-level variation in offer acceptance rates vastly exceeds variation in the traditional, 1-year survival benchmark. Key opportunities to boost utilization include donation after circulatory death and hepatitis C virus (HCV)+ organs; acute kidney injury and suboptimal biopsy kidneys; older and steatotic livers.

SUMMARY

Underutilization of less-than-ideal, yet transplant-worthy organs remains an obstacle to maximizing the impact of the U.S. transplant system. The increased risk of inferior posttransplant outcomes must always be weighed against the risks of remaining on the waitlist. Advanced perfusion technologies; tuning allocation systems for placement efficiency; and data-driven clinical decision support have the potential to increase utilization of medically complex organs.

Kidney utility and futility

Changes in kidney allocation coupled with the COVID-19 pandemic have placed tremendous strain on current systems of organ distribution and logistics. Although the number of deceased donors continues to rise annually in the United States, the proportion of marginal deceased donors (MDDs) is disproportionately growing. Cold ischemia times and kidney discard rates are rising in part related to inadequate planning, resources, and shortages. Complexity in kidney allocation and distribution has contributed to this dilemma. Logistical issues and the ability to reperfuse the kidney within acceptable time constraints increasingly determine clinical decision-making for organ acceptance. We have a good understanding of the phenotype of "hard to place" MDD kidneys, yet continue to promote a "one size fits all" approach to organ allocation. Allocation and transportation systems need to be agile, mobile, and flexible in order to accommodate the expanding numbers of MDD organs. By identifying "hard to place" MDD kidneys early and implementing a "fast-track" or open offer policy to expedite placement, the utilization rate of MDDs would improve dramatically. Organ allocation and distribution based on location, motivation, and innovation must lead the way. In the absence of change, we are sacrificing utility for futility and discard rates will continue to escalate.

The New Distance-Based Kidney Allocation System: Implications for Patients, Transplant Centers, and Organ Procurement Organizations

Purpose of Review

The goal of deceased donor kidney allocation policy is to provide objective prioritization for donated kidneys, and policy has undergone a series of revisions in the past decade in attempt to achieve equity and utility in access to kidney transplantation. Most recently, to address geographic disparities in access to kidney transplantation, the Kidney Allocation System changed to a distance-based allocation system—colloquially termed “KAS 250”—moving away from donor service areas as the geographic basis of allocation. We review the early impact of this policy change on access to transplant for patients, and on complexity of organ allocation and transplantation for transplant centers and organ procurement organizations.

Recent Findings

Broader sharing of kidneys has increased complexity of the allocation system, as transplant centers and OPOs now interact in larger networks. The increased competition resulting from this system, and the increased operational burden on centers and OPOs resulting from greater numbers of organ offers, may adversely affect organ utilization. Preliminary results suggest an increase in transplant rate overall but a trend toward higher kidney discard and increased cold ischemia time.

Summary

The KAS 250 allocation policy changed the geographic basis of deceased donor kidney distribution in a manner that is intended to reduce geographic disparities in access to kidney transplantation. Close monitoring of this policy’s impact on patients, transplant center behavior, and process measures is critical to the aim of maximizing access to transplant while achieving transplant equity.