Risk aversion in the use of complex kidneys in paired exchange programs: Opportunities for even more transplants?

This retrospective review of the largest United States kidney exchange reports characteristics, utilization, and recipient outcomes of kidneys with simple compared to complex anatomy and extrapolates reluctance to accept these kidneys. Of 3105 transplants performed, only 12.8% were right kidneys and 23.1% had multiple renal arteries. 59.3% of centers used fewer right kidneys than expected and 12.1% transplanted zero right kidneys or kidneys with more than 1 artery. Five centers transplanted a third of these kidneys (35.8% of right kidneys and 36.7% of kidneys with multiple renal arteries). 22.5% and 25.5% of centers currently will not entertain a match offer for a left or right kidney with more than one artery, respectively. There were no significant differences in all-cause graft failure or death-censored graft loss for kidneys with multiple arteries, and a very small increased risk of graft failure for right kidneys versus left of limited clinical relevance for most recipients. Kidneys with complex anatomy can be used with excellent outcomes at many centers. Variation in use (lack of demand) for these kidneys reduces the number of transplants, so systems to facilitate use could increase demand. We cannot know how many donors are turned away because perceived demand is limited.

The benefit to waitlist patients in a national paired kidney exchange program: Exploring characteristics of chain end living donor transplants.

Nondirected kidney donors can initiate living donor chains that end to patients on the waitlist. We compared 749 National Kidney Registry (NKR) waitlist chain end transplants to other transplants from the NKR and the Scientific Registry of Transplant Recipients between February 2008 and September 2020. Compared to other NKR recipients, chain end recipients were more often older (53 vs. 52 years), black (32% vs. 15%), publicly insured (71% vs. 46%), and spent longer on dialysis (3.0 vs. 1.0 years). Similar differences were noted between chain end recipients and non-NKR living donor recipients. Black patients received chain end kidneys at a rate approaching that of deceased donor kidneys (32% vs. 34%). Chain end donors were older (52 vs. 44 years) with slightly lower glomerular filtration rates (93 vs. 98 ml/min/1.73 m2 ) than other NKR donors. Chain end recipients had elevated risk of graft failure and mortality compared to control living donor recipients (both p < .01) but lower graft failure (p = .03) and mortality (p < .001) compared to deceased donor recipients. Sharing nondirected donors among a multicenter network may improve the diversity of waitlist patients who benefit from living donation.

Ensuring the need is met: A 50-year simulation study of the National Kidney Registry's family voucher program.

The National Kidney Registry (NKR) Advanced Donation Program enables living donors the opportunity to donate altruistically, or in advance of a potential recipient's transplant, and to receive a voucher that can be redeemed for a future transplant facilitated by the NKR. Family vouchers allow a donor to identify multiple individuals within their immediate family, with the first person in that group in need of a transplant being prioritized to receive a kidney. An increase in vouchers introduces concerns that demand for future voucher redemptions could exceed the supply of available donors and kidneys. A Monte Carlo simulation model was constructed to estimate the annual number of voucher redemptions relative to the number of kidneys available over a 50-year time horizon under several projected scenarios for growth of the program. In all simulated scenarios, the number of available kidneys exceeded voucher redemptions every year. While not able to account for all real-life scenarios, this simulation study found that the NKR should be able to satisfy the likely redemption of increasing numbers of vouchers under a range of possible scenarios over a 50-year time horizon. This modeling exercise suggests that a donor family's future needs can be satisfied through the voucher program.

The "oldest and coldest" shipped living donor kidneys transplanted through kidney paired donation.

To date, thousands of living donor kidneys have been shipped through kidney paired donation (KPD). To expand on this growing segment of living donor transplantation, we evaluated the effect of advanced age donation ("oldest kidneys") and prolonged cold ischemia time ("coldest kidneys") on graft function and survival using the National Kidney Registry database from February 2008 to May 2018. Donors were stratified by age at time of donation (<65 or ≥65 years) and kidneys were stratified by cold ischemia time (<16 or ≥16 hours). We evaluated delayed graft function and death-censored graft failure (DCGF) for up to seven posttransplant years. Of the 2363 shipped living donor kidney transplants, 4.1% of donors were ≥65 years and 6.0% of transplanted kidneys had cold ischemia times ≥16 hours. Delayed graft function and DCGF occurred in 5.2% and 4.7% of cases. There were no significant associations between delayed graft function and donor age (P = .947) or cold ischemia (P = .532). Donor age and cold ischemia time were not predictive of delayed graft function (OR = 0.86,1.20; P = .8, .6) or DCGF (HR = 1.38,0.35, P = .5, .1). These findings may alleviate concerns surrounding the utilization of kidneys from older donors or those originating from distant transplant centers.

Factors predicting kidney delayed graft function among recipients of simultaneous liver-kidney transplantation: A single-center experience.

BACKGROUND: Kidney delayed graft function (kDGF) remains a challenging problem following simultaneous liver and kidney transplantation (SLKT) with a reported incidence up to 40%. Given the scarcity of renal allografts, it is crucial to minimize the development of kDGF among SLKT recipients to improve patient and graft outcomes. We sought to assess the role of preoperative recipient and donor/graft factors on developing kDGF among recipients of SLKT. METHODS: A retrospective review of 194 patients who received SLKT in the period from January 2004 to March 2017 in a single center was performed to assess the effect of preoperative factors on the development of kDGF. RESULTS: Kidney delayed graft function was observed in 95 patients (49%). Multivariate analysis revealed that donor history of hypertension, cold static preservation of kidney grafts [versus using hypothermic pulsatile machine perfusion (HPMP)], donor final creatinine, physiologic MELD, and duration of delay of kidney transplantation after liver transplantation were significant independent predictors for kDGF. kDGF is associated with worse graft function and patient and graft survival. CONCLUSIONS: Kidney delayed graft function has detrimental effects on graft function and graft survival. Understanding the risks and combining careful perioperative patient management, proper recipient selection and donor matching, and graft preservation using HPMP would decrease kDGF among SLKT recipients.

The Role of Media in Non-Directed (Altruistic) Living Kidney Donation.

This study seeks to characterize how non-directed living kidney donors use media and informational resources over the course of their kidney donation journey. We conducted semi-structured interviews with non-directed donors (NDDs) who initiated kidney transplant chains. Interview transcripts were reviewed and references to media or informational resources were classified by type and pattern of use. More than half (57%) of NDDs reported that an identifiable media or informational resource resulted in their initial interest in donation. Two-thirds (67%) of NDDs cited the influence of stories and personal narratives on their decision to donate. After transplant, media and informational resources were used to promote organ donation, connect with other donors or recipients, and reflect on donation. From the study's findings, we conclude that media and informational resources play an important role in the process of donation for NDDs, including inspiring interest in donation through personal narratives. Media sources provide emotionally and intellectually compelling discussions that motivate potential donors. The results of this study may facilitate the development of more targeted outreach to potential donors through use of personal narratives in articles and television programming about donation.

Innovations in kidney paired donation transplantation.

PURPOSE OF REVIEW: To analyze the innovations that have increased the reliability, convenience, and outcomes of kidney paired donation (KPD) that has led to thousands of living donor kidney transplants across the United States. RECENT FINDINGS: Over the past 10 years, KPD has grown over 200% on an annual basis. Though concerns had existed over cold ischemia time, research has shown that there is no correlation between travel time of a shipped kidney and the transplant outcome. The voucher program has started to continue to expand how to overcome obstacles to donation by solving the issue of a pair chronological incompatibility. SUMMARY: KPD is a relatively new field and the innovations it has spawned should continue to improve availability of high-quality living donor organs. The introduction of the family voucher should continue this trend.

The first 9 years of kidney paired donation through the National Kidney Registry: Characteristics of donors and recipients compared with National Live Donor Transplant Registries.

The practice of kidney paired donation (KPD) is expanding annually, offering the opportunity for live donor kidney transplant to more patients. We sought to identify if voluntary KPD networks such as the National Kidney Registry (NKR) were selecting or attracting a narrower group of donors or recipients compared with national registries. For this purpose, we merged data from the NKR database with the Scientific Registry of Transplant Recipients (SRTR) database, from February 14, 2008, to February 14, 2017, encompassing the first 9 years of the NKR. Compared with all United Network for Organ Sharing (UNOS) live donor transplant patients (49 610), all UNOS living unrelated transplant patients (23 319), and all other KPD transplant patients (4236), the demographic and clinical characteristics of NKR transplant patients (2037) appear similar to contemporary national trends. In particular, among the NKR patients, there were a significantly (P < .001) greater number of retransplants (25.6% vs 11.5%), hyperimmunized recipients (22.7% vs 4.3% were cPRA >80%), female recipients (45.9% vs 37.6%), black recipients (18.2% vs 13%), and those on public insurance (49.7% vs 41.8%) compared with controls. These results support the need for greater sharing and larger pool sizes, perhaps enhanced by the entry of compatible pairs and even chains initiated by deceased donors, to unlock more opportunities for those harder-to-match pairs.

Spirituality and religiosity of non-directed (altruistic) living kidney donors.

AIMS AND OBJECTIVES: To describe the spirituality and religiosity of 30 non-directed (altruistic) living kidney donors in the USA and explore how they may have affected their motivations to donate and donation process experiences. BACKGROUND: The rise in non-directed donors and their ability to initiate kidney chains offer a novel approach to help alleviate the overextended kidney transplant wait list in the USA. However, little is known about the non-directed donors' motivations, characteristics and experiences. DESIGN: We conducted a qualitative-dominant study and used a grounded theory approach to analyse data. METHODS: Thirty participants completed in-depth interviews between April 2013-April 2015. Three analysts independently read and coded interview transcripts. Grounded theory techniques were used to develop descriptive categories and identify topics related to the non-directed donors donation experience. RESULTS: Sixteen of the 30 non-directed donorss discussed the topic of spirituality and religiosity when describing their donation experiences, regardless of whether they were actively practising a religion at the time of donation. Specifically, three themes were identified within spirituality and religiosity: motivation to donate, support in the process, and justification of their donation decisions postdonation. CONCLUSIONS: Findings from this study are the first to describe how spirituality and religiosity influenced the experiences of U.S. non-directed donorss and may help improve non-directed donors educational resources for future spiritual or religious non-directed donors, and the overall non-directed donors donation experience in efforts to increase the living donor pool. RELEVANCE TO CLINICAL PRACTICE: Spirituality and religiosity are often overlooked yet potentially influential factors in Western medicine, as demonstrated through the experiences of Jehovah's Witnesses and their religious restrictions while undergoing surgery and the beliefs of Christian Scientists against taking medications and receiving medical procedures. Understanding needs of non-directed donors specifically with spirituality and religiosity can better position kidney transplant centres and teams to improve predonation screening of non-directed donor candidates and provide support services during the donation process.

Outcomes of shipped live donor kidney transplants compared with traditional living donor kidney transplants.

The disparity between kidney transplant candidates and donors necessitates innovations to increase organ availability. Transporting kidneys allows for living donors and recipients to undergo surgery with a familiar transplant team, city, friends, and family. The effect of shipping kidneys and prolonged cold ischemia time (CIT) with living donor transplantation outcomes is not clearly known. This retrospective matched (age, gender, race, and year of procedure) cohort study compared allograft outcomes for shipped live donor kidney transplants and nonshipped living donor kidney transplants. Fifty-seven shipped live donor kidneys were transplanted from 31 institutions in 26 cities. The mean shipping distance was 1634 miles (range 123-2811) with mean CIT of 12.1 ± 2.8 h. The incidence of delayed graft function in the shipped cohort was 1.8% (1/57) compared to 0% (0/57) in the nonshipped cohort. The 1-year allograft survival was 98% in both cohorts. There were no significant differences between the mean serum creatinine values or the rates of serum creatinine decline in the immediate postoperative period even after adjusted for gender and differences in recipient and donor BMI. Despite prolonged CITs, outcomes for shipped live donor kidney transplants were similar when compared to matched nonshipped living donor kidney transplants.

Kidney paired donation in the presence of donor-specific antibodies.

Incompatible donor/recipient pairs with broadly sensitized recipients have difficulty finding a crossmatch-compatible match, despite a large kidney paired donation pool. One approach to this problem is to combine kidney paired donation with lower-risk crossmatch-incompatible transplantation with intravenous immunoglobulin. Whether this strategy is non-inferior compared with transplantation of sensitized patients without donor-specific antibody (DSA) is unknown. Here we used a protocol including a virtual crossmatch to identify acceptable crossmatch-incompatible donors and the administration of intravenous immunoglobulin to transplant 12 HLA-sensitized patients (median calculated panel reactive antibody 98%) with allografts from our kidney paired donation program. This group constituted the DSA(+) kidney paired donation group. We compared rates of rejection and survival between the DSA(+) kidney paired donation group with a similar group of 10 highly sensitized patients (median calculated panel reactive antibody 85%) that underwent DSA(-) kidney paired donation transplantation without intravenous immunoglobulin. At median follow-up of 22 months, the DSA(+) kidney paired donation group had patient and graft survival of 100%. Three patients in the DSA(+) kidney paired donation group experienced antibody-mediated rejection. Patient and graft survival in the DSA(-) kidney paired donation recipients was 100% at median follow-up of 18 months. No rejection occurred in the DSA(-) kidney paired donation group. Thus, our study provides a clinical framework through which kidney paired donation can be performed with acceptable outcomes across a crossmatch-incompatible transplant.

Apheresis of Deceased Donors as a New Source of Mobilized Peripheral Blood Hematopoietic Stem Cells for Transplant Tolerance.

BACKGROUND: Solid organ transplantation is the therapy of choice for many patients with end-stage organ failure; however, recipients must remain on lifelong immunosuppression, leaving them susceptible to infections and cancer. The study of transplant tolerance to prolong graft survival in the absence of immunosuppression has been restricted to recipients of living donor allografts; however, deceased donors significantly outnumber living donors. Mobilization of hematopoietic stem cells (HSCs) from the bone marrow to peripheral blood (PB) could allow PB-HSCs to be used to induce tolerance in deceased donor kidney recipients; however, a major concern is the well-known concomitant mobilization of immune cells into the liver. METHODS: We mobilized HSCs to the PD using a protocol of 2 doses of granulocyte colony-stimulating factor and 1 dose of plerixafor, followed by the collection of mobilized cells via apheresis in 3 deceased donors. The physiological, laboratory, and radiographic parameters were monitored throughout the procedure. Longitudinal biopsies were performed to assess the potential for ectopic liver mobilization. RESULTS: The use of both agents led to the successful mobilization of peripheral blood CD34+ cells, demonstrating the potential for use in transplant tolerance protocols. Increased immune cell trafficking into the liver was not observed, and apheresis of mobilized cells resulted in a uniform decrease in all liver leukocyte subsets. CONCLUSIONS: HSCs can be mobilized and collected from the PB of brain-dead donors. This new approach may facilitate the dissemination of immune tolerance trials beyond living-donor kidney transplantation to deceased-donor transplantation, without sacrificing the transplantability of the liver.

Kidney paired donation: advancements and future directions.

PURPOSE OF REVIEW: Kidney paired donation (KPD) has become a viable option for patients in need of a kidney transplant who have a willing, but incompatible living donor. The purpose of this review is to highlight the recent advances in KPD including shipping live-donor kidneys to their intended recipient, enrolling compatible pairs, and combining KPD with desensitization. RECENT FINDINGS: KPD has been expanded and facilitated by multiple organizations. KPD chains have been extended from single-center two-way 'swaps' to transcontinental KPD chains in which living-donor organs have been shipped without compromising outcomes. Living-donor kidneys have been shipped transcontinentally on commercial airlines with great success. Enrollment of compatible donor--recipient pairs, particularly those with blood group O donors, is one strategy that has been employed to extend KPD to even more patients. It has also become more apparent that KPD can be successfully combined with desensitization in order to transplant our most immunologically challenging patients. SUMMARY: KPD is becoming an established method of transplantation at transplant centers throughout the world. Advancements have been made through shipping living-donor kidneys, combining KPD with desensitization, and enrolling compatible pairs.

Voucher-Based Kidney Donation and Redemption for Future Transplant.

Importance: Policy makers, transplant professionals, and patient organizations agree that there is a need to increase the number of kidney transplants by facilitating living donation. Vouchers for future transplant provide a means of overcoming the chronological incompatibility that occurs when the ideal time for living donation differs from the time at which the intended recipient actually needs a transplant. However, uncertainty remains regarding the actual change in the number of living kidney donors associated with voucher programs and the capability of voucher redemptions to produce timely transplants. Objective: To examine the consequences of voucher-based kidney donation and the capability of voucher redemptions to provide timely kidney allografts. Design, Setting, and Participants: This multicenter cohort study of 79 transplant centers across the US used data from the National Kidney Registry from January 1, 2014, to January 31, 2021, to identify all family vouchers and patterns in downstream kidney-paired donations. The analysis included living kidney donors and recipients participating in the National Kidney Registry family voucher program. Exposures: A voucher was provided to the intended recipient at the time of donation. Vouchers had no cash value and could not be sold, bartered, or transferred to another person. When a voucher was redeemed, a living donation chain was used to return a kidney to the voucher holder. Main Outcomes and Measures: Deidentified demographic and clinical data from each kidney donation were evaluated, including the downstream patterns in kidney-paired donation. Voucher redemptions were separately evaluated and analyzed. Results: Between 2014 and 2021, 250 family voucher-based donations were facilitated. Each donation precipitated a transplant chain with a mean (SD) length of 2.3 (1.6) downstream kidney transplants, facilitating 573 total transplants. Of those, 111 transplants (19.4%) were performed in highly sensitized recipients. Among 250 voucher donors, the median age was 46 years (range, 19-78 years), and 157 donors (62.8%) were female, 241 (96.4%) were White, and 104 (41.6%) had blood type O. Over a 7-year period, the waiting time for those in the National Kidney Registry exchange pool decreased by more than 3 months. Six vouchers were redeemed, and 3 of those redemptions were among individuals with blood type O. The time from voucher redemption to kidney transplant ranged from 36 to 155 days. Conclusions and Relevance: In this study, the family voucher program appeared to mitigate a major disincentive to living kidney donation, namely the reluctance to donate a kidney in the present that could be redeemed in the future if needed. The program facilitated kidney donations that may not otherwise have occurred. All 6 of the redeemed vouchers produced timely kidney transplants, indicating the capability of the voucher program.

How Can We Help Alleviate the Financial Concerns of Non-Directed (Altruistic) Living Kidney Donors?

INTRODUCTION: The recent increase in non-directed donors (NDDs) in the United States (U.S.) may help reduce the overwhelming number of patients on the waitlist. However, non-directed donation may be limiting its full potential. Out-of-pocket donation costs upward of $8,000 may be a barrier to potential donors with altruistic tendencies, but inadequate financial support. This study aimed to describe the financial concerns of 31 U.S. NDDs. METHODS: We conducted qualitative interviews and administered quantitative demographic surveys between April 2013 and April 2015. Interview transcripts were analyzed using grounded theory techniques to describe and expand on themes relevant to the NDD experience. FINDINGS: We identified 4 sub-themes related to the theme of financial concerns: (1) direct costs related to transportation, lodging, and parking, (2) indirect costs of lost wages encountered from taking time off work to recover from surgery, (3) sources of financial support, and (4) suggestions for alleviating donor financial burden. Two thirds of participants (20) expressed concerns about direct and indirect donation costs. 11 NDDs reported the negative impact of direct costs,15 NDDs had concerns about indirect costs; only 7 donors received supplemental financial support from state mandates and transplant programs. DISCUSSION: Understanding the financial concerns of NDDs may guide improvements in the NDD donation experience that could support individuals who are interested in donating but lack the financial stability to donate. Removing financial disincentives may help increase nondirected donation rates, increase the living donor pool, and the number of kidneys available for transplantation.

Patient and Kidney Allograft Survival with National Kidney Paired Donation.

BACKGROUND AND OBJECTIVES: In the United States, kidney paired donation networks have facilitated an increasing proportion of kidney transplants annually, but transplant outcome differences beyond 5 years between paired donation and other living donor kidney transplant recipients have not been well described. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using registry-linked data, we compared National Kidney Registry (n=2363) recipients to control kidney transplant recipients (n=54,497) (February 2008 to December 2017). We estimated the risk of death-censored graft failure and mortality using inverse probability of treatment weighted Cox regression. The parsimonious model adjusted for recipient factors (age, sex, black, race, body mass index ≥30 kg/m2, diabetes, previous transplant, preemptive transplant, public insurance, hepatitis C, eGFR, antibody depleting induction therapy, year of transplant), donor factors (age, sex, Hispanic ethnicity, body mass index ≥30 kg/m2), and transplant factors (zero HLA mismatch). RESULTS: National Kidney Registry recipients were more likely to be women, black, older, on public insurance, have panel reactive antibodies >80%, spend longer on dialysis, and be previous transplant recipients. National Kidney Registry recipients were followed for a median 3.7 years (interquartile range, 2.1-5.6; maximum 10.9 years). National Kidney Registry recipients had similar graft failure (5% versus 6%; log-rank P=0.2) and mortality (9% versus 10%; log-rank P=0.4) incidence compared with controls during follow-up. After adjustment for donor, recipient, and transplant factors, there no detectable difference in graft failure (adjusted hazard ratio, 0.95; 95% confidence interval, 0.77 to 1.18; P=0.6) or mortality (adjusted hazard ratio, 0.86; 95% confidence interval, 0.70 to 1.07; P=0.2) between National Kidney Registry and control recipients. CONCLUSIONS: Even after transplanting patients with greater risk factors for worse post-transplant outcomes, nationalized paired donation results in equivalent outcomes when compared with control living donor kidney transplant recipients.

Delayed Implantation of Pumped Kidneys Decreases Renal Allograft Futility in Combined Liver-Kidney Transplantation.

BACKGROUND: Combined liver-kidney transplantation (CLKT) improves survival for liver transplant recipients with renal dysfunction; however, the tenuous perioperative hemodynamic and metabolic milieu in high-acuity CLKT recipients increases delayed graft function and kidney allograft failure. We sought to analyze whether delayed KT through pumping would improve kidney outcomes following CLKT. METHODS: A retrospective analysis (University of California Los Angeles [n = 145], Houston Methodist Hospital [n = 79]) was performed in all adults receiving CLKT at 2 high-volume transplant centers from February 2004 to January 2017, and recipients were analyzed for patient and allograft survival as well as renal outcomes following CLKT. RESULTS: A total of 63 patients (28.1%) underwent delayed implantation of pumped kidneys during CLKT (dCLKT) and 161 patients (71.9%) received early implantation of nonpumped kidneys during CLKT (eCLKT). Most recipients were high-acuity with median biologic model of end-stage liver disease (MELD) score of, 35 for dCLKT and 34 for eCLKT (P = ns). Pretransplant, dCLKT had longer intensive care unit stay, were more often intubated, and had greater vasopressor use. Despite this, dCLKT exhibited improved 1-, 3-, and 5-year patient and kidney survival (P = 0.02) and decreased length of stay (P = 0.001), kidney allograft failure (P = 0.012), and dialysis duration (P = 0.031). This reduced kidney allograft futility (death or continued need for hemodialysis within 3 mo posttransplant) for dCLKT (6.3%) compared with eCLKT (19.9%) (P = 0.013). CONCLUSIONS: Delayed implantation of pumped kidneys is associated with improved patient and renal allograft survival and decreased hospital length of stay despite longer kidney cold ischemia. These data should inform the ethical debate as to the futility of performing CLKT in high-acuity recipients.