Temporal trends in kidney paired donation in the United States: 2006-2021 UNOS/OPTN database analysis.

Kidney paired donation (KPD) is a major innovation that is changing the landscape of kidney transplantation in the United States. We used the 2006-2021 United Network for Organ Sharing data to examine trends over time. KPD is increasing, with 1 in 5 living donor kidney transplants (LDKTs) in 2021 facilitated by KPD. The proportion of LDKT performed via KPD was comparable for non-Whites and Whites. An increasing proportion of KPD transplants are going to non-Whites. End-chain recipients are not identified in the database. To what extent these trends reflect how end-chain kidneys are allocated, as opposed to increase in living donation among minorities, remains unclear. Half the LDKT in 2021 in sensitized (panel reactive antibody ≥ 80%) and highly sensitized (panel reactive antibody ≥ 98%) groups occurred via KPD. Yet, the proportion of KPD transplants performed in sensitized recipients has declined since 2013, likely due to changes in the deceased donor allocation policies and newer KPD strategies such as compatible KPD. In 2021, 40% of the programs reported not performing any KPD transplants. Our study highlights the need for understanding barriers to pursuing and expanding KPD at the center level and the need for more detailed and accurate data collection at the national level.

Anonymity in Kidney Paired Donation: A Systematic Review of Reasons.

The objective of this study was to investigate reasons for or against anonymity that are pertinent to kidney paired donations (KPD). We conducted a systematic review of reasons using PubMed and Google Scholar until May 2022 and through snowballing. Inclusion criteria were publications that: 1) discussed organ donation anonymity; 2) was peer-reviewed; 3) presented at least one reason on anonymity. Exclusion criteria: 1) not published in a scientific journal; 2) grey literature and dissertations. Four researchers independently reviewed and selected papers based on the criteria, extracted text passages and coded them into narrow and broad reason types, selected reasons that were valid for kidney paired donations. 50 articles were included, 62 narrow reasons (n = 24 for; n = 38 against) and 13 broad reasons were coded. Broad reasons were: protection against harm, general benefits, gratitude, curiosity, unrealistic to implement, fundamental rights, respect people's wishes, professional neutrality, timing is important, information disclosure, altruism, reciprocity and donation pool. We did not find reasons that justify legal prohibition of donor-recipient interactions for KPD, if they consented to meet. Professional counselling, follow-up and careful evaluations to prevent potential harm.

Changing patterns of clinical decision making: are falling numbers of antibody incompatible transplants related to the increasing success of the UK Living Kidney Sharing Scheme? A national cohort study.

Antibody incompatibility is a barrier to living kidney transplantation; antibody incompatible transplantation (AIT) is an accepted treatment modality, albeit higher risk. This study aims to determine changes to clinical decision making and access to AIT in the UK. An electronic survey was sent to all UK renal transplant centres (n = 24), in 2014, and again in 2018. Questions focused on entry & duration in the UKLKSS for HLA and ABO-incompatible pairs, Can and provision of direct AIT transplantation within those centres. Between 2014 & 2018, the duration recommended for patients in the UKLKSS increased. In 2014, 34.8% of centres reported leaving HLA-i pairs in the UKLKSS indefinitely, or reviewing on a case by case basis, by 2018 this increased to 61%. Centres offering direct HLA-i transplantation reduced from 58% to 37%. For low titre (1:8) ABO-i recipients, 66% of centres recommended at least 9 months (3 matching runs) in the UKLKSS scheme in 2018, compared to 47% in 2014, 50% fewer units consider direct ABO-i transplantation for unsuccessful pairs with high ABO titres (>1:512). Over time, clinicians appear to be facilitating more conservative management of AIT patients, potentially limiting access to living donor transplantation.

Transplanting the Untransplantable.

With implementation of the Kidney Allocation System, the growth of kidney paired donation programs, and advances in desensitization and immunosuppression, the outlook for "untransplantable" kidney transplantation candidates has never been more promising. The Kidney Allocation System prioritized compatible matches for candidates with calculated panel-reactive antibody levels of 98%, 99%, or 100% and broadened allocation of non-A1 and non-A1-B subgroup kidneys to blood group type B candidates. Concurrently, the growth of kidney paired donation programs and use of incompatible transplantation as part of kidney paired donation to achieve "more compatible" kidney transplantation has improved options for candidates with an incompatible living donor. Finally, advances in desensitization and immunosuppression have strengthened the ability to manage donor-specific antibodies and antibody-mediated rejection. Although no patient should be labeled "untransplantable" due to blood group type or donor-specific antibody, all candidates should be provided with individualized and realistic counseling regarding their anticipated wait times for deceased donor or kidney paired donation matching, with early referral to expert centers when needed. In this Perspective, we consider blood group type ABO incompatibility, HLA antigen incompatibility, antibody-mediated rejection, kidney paired donation, and recent developments in incompatible transplantation in more depth and recommend an approach to the sensitized candidate.

Paired kidney exchange transplantation - pushing the boundaries.

The scarcity of living organ donors makes it imperative to develop newer innovations to optimize and maximize the utilization of the available pool. ABO and HLA sensitization are important immunological barriers in renal transplant and can potentially lead to rejection of almost one-third of the willing living donors. Paired kidney exchange (PKE) is a rapidly growing method used to overcome these barriers and has grown in popularity over the last three decades since its introduction in 1986. Evolution of the matching strategies and use of complex algorithms has led to increase in the number of possible matches thereby benefiting multiple recipients. The use of altruistic donors and compatible pairs has also helped in increasing the possible exchanges. This review provides an in-depth analysis of the evolution, the present global scenario, and the future of PKE. It also discusses the recent trends of advanced donation, trans-organ paired exchange and global kidney exchange and the associated ethical concerns.

Crossing borders to facilitate live donor kidney transplantation: the Czech-Austrian kidney paired donation program - a retrospective study.

Kidney paired donation (KPD) is a valuable tool to overcome immunological barriers in living donor transplantation. While small national registries encounter difficulties in finding compatible matches, multi-national KPD may be a useful strategy to facilitate transplantation. The Czech (Prague) and Austrian (Vienna) KPD programs, both initiated in 2011, were merged in 2015. A bi-national algorithm allowed for ABO- and low-level HLA antibody-incompatible exchanges, including the option of altruistic donor-initiated domino chains. Between 2011 and 2019, 222 recipients and their incompatible donors were registered. Of those, 95.7% (Prague) and 67.9% (Vienna) entered into KPD registries, and 81 patients received a transplant (95% 3-year graft survival). Inclusion of ABO-incompatible pairs in the Czech program contributed to higher KPD transplant rates (42.6% vs. 23.6% in Austria). After 2015 (11 bi-national match runs), the median pool size increased to 18 pairs, yielding 33 transplants (8 via cross-border exchanges). While matching rates doubled in Austria (from 9.1% to 18.8%), rates decreased in the Czech program, partly due to implementation of more stringent HLA antibody thresholds. Our results demonstrate the feasibility of merging small national KPD programs to increase pool sizes and may encourage the implementation of multi-national registries to expand the full potential of KPD.

Kidney exchange strategies: new aspects and applications with a focus on deceased donor-initiated chains.

Kidney paired donation (KPD) is a valuable way to overcome immunological incompatibility in the context of living donation, and several strategies have been implemented to boost its development. In this article, we reviewed the current state of the art in this field, with a particular focus on advanced KPD strategies, including the most recent idea of initiating living donor (LD) transplantation chains with a deceased donor (DD) kidney, first applied successfully in 2018. Since then, Italy has been running a national programme in which a chain-initiating kidney is selected from a DD pool and allocated to a recipient with an incompatible LD, and the LD's kidney is transplanted into a patient on the waiting list (WL). At this stage, since the ethical and logistic issues have been managed appropriately, KPD starting with a DD has proved to be a feasible strategy. It enables transplants in recipients of incompatible pairs without the need for desensitizing and also benefits patients on the WL who are allocated chain-ending kidneys from LDs (prioritizing sensitized patients and those on the WL for longer).

Pre- and postdonation kidney function in donors of a kidney paired donation with unique criteria for donor glomerular filtration rate - a longitudinal cohort analysis.

Baseline predonation estimated GFR (eGFR) appears to predict the risk of postdonation chronic kidney disease in live donors. New KIDGO guidelines recommend an eGFR ≥90 ml/min/1.73 m2 as an acceptable level of glomerular filtration rate (GFR) for kidney donation. In the Australian Paired Kidney Exchange (AKX) program, all donors with a raw measured GFR (mGFR) ≥80 ml/min are deemed suitable for donation, but the significance of this selection indicator is unclear. We analysed the first 129 live donors in the AKX program with at least 1-year follow-up linking records in the AKX database and ANZDATA. There were 73 male and 56 female donors; mean (±SD) age was 53 ± 11 years. Predonation eGFR was 94 ± 13 ml/min/1.73 m2 , mGFR 99 ± 17 ml/min/1.73 m2 and raw mGFR 108 ± 18 ml/min. Baseline eGFR was <80 ml/min/1.73 m2 in 19 donors, and <90 ml/min/1.73 m2 in 42 donors. At 1 year postdonation eGFR was 68 ± 15 ml/min/1.73 m2 and the predicted eGFR at 30 years postdonation was on average 50 (29-83) ml/min/1.73 m2 . The hypothetical mean age at end-stage kidney disease was estimated to be 145 (95% CI 120-263) years. Over 30% of AKX live donors would have been excluded from donation using KDIGO guidelines. Using AKX donor guidelines, the majority of donors with predicted eGFR <30 ml/min/1.73 m2 30-year postdonation were aged ≥50 years. Long-term outcome data on AKX donors with low eGFR will need careful monitoring.

Finding long chains in kidney exchange using the traveling salesman problem.

As of May 2014 there were more than 100,000 patients on the waiting list for a kidney transplant from a deceased donor. Although the preferred treatment is a kidney transplant, every year there are fewer donors than new patients, so the wait for a transplant continues to grow. To address this shortage, kidney paired donation (KPD) programs allow patients with living but biologically incompatible donors to exchange donors through cycles or chains initiated by altruistic (nondirected) donors, thereby increasing the supply of kidneys in the system. In many KPD programs a centralized algorithm determines which exchanges will take place to maximize the total number of transplants performed. This optimization problem has proven challenging both in theory, because it is NP-hard, and in practice, because the algorithms previously used were unable to optimally search over all long chains. We give two new algorithms that use integer programming to optimally solve this problem, one of which is inspired by the techniques used to solve the traveling salesman problem. These algorithms provide the tools needed to find optimal solutions in practice.

Case Report of Kidney Paired Donation (KPD) with Desensitization: the Strategy and Experience of 3-Way KPD in Samsung Medical Center.

As the need for the organ donation increases, strategies to increase kidney transplantation (KT) through expanded living donation have become essential. These include kidney paired donation (KPD) programs and desensitization in incompatible transplantations. KPD enables kidney transplant candidates with incompatible living donors to join a registry with other incompatible pairs in order to find potentially compatible living donor. Positive cross match and ABO incompatible transplantation has been successfully accomplished in selective cases with several pre-conditionings. Patients who are both difficult-to-match due to broad sensitization and hard-to-desensitize because of donor conditions can often be successfully transplanted through a combination of KPD and desensitization. According to the existing data, KPD can increase the number of KTs from living donors with excellent clinical results. This is also a cost-effective treatment as compared with dialysis and desensitization protocols. We carried out 3-way KPD transplantation with one highly sensitized, positive cross match pair and with two ABO incompatible pairs. Herein we report our first successful 3-way KPD transplantation in a single center. To maximize donor-recipient matching and minimize immunologic risk, KPD programs should use proper algorithms with desensitization to identify optimal donor with simultaneous two-, three- or more complex multi-way exchanges.

Cold ischemia time up to 16 hours has little impact on living donor kidney transplant outcomes in the era of kidney paired donation.

In living donor transplantation, cold ischemia time is a concern in transplants involving kidney paired donation. The impact of cold ischemia time over eight hours is unknown. Here we examined the association of cold ischemia time with delayed graft function and allograft loss among 48,498 living recipients in the Scientific Registry of Transplant Recipients registry. The incidence of delayed graft function was low but significantly higher among patients with longer cold ischemia times (0-2.0 hours: 3.3%; 2.1-4.0 hours: 3.9%; 4.1-8.0 hours: 4.3%; 8.1-16.0 hours: 5.5%). In multivariate analyses, only those with cold ischemia times of 8.1-16.0 hours had increased odds of delayed graft function (odds ratio 1.47; 95% confidence interval 1.05-2.05) compared to patients with times of 0-2.0 hours. In multivariate time-to-event analyses, cold ischemia times of 16 hours or less were not associated with allograft loss from any cause including death or death-censored graft loss with hazard ratios for cold ischemia times between 8.0-16.0 hours of 0.97 (95% confidence interval 0.74-1.26) and 1.09 (0.81-1.48) compared to patients with times of 0-2.0 hours). The results were consistent in paired and non-kidney paired donation transplants and in those with living donors over 50 years of age. In subgroup analysis restricted to kidney paired donation recipients, there was no difference in the risk of delayed graft function with an odds ratio of 1.40 (0.88, 2.40) or all-cause graft loss with a hazard ratio of 0.89 (0.62, 1.30) in transplant recipients who received kidneys that were shipped versus not shipped. Thus, a cold ischemia time up to 16 hours has limited impact on living donor outcomes. These findings may help expand living donor transplantation through kidney paired donation.

Impact of single centre kidney paired donation transplantation to increase donor pool in India: a cohort study.

In a living donor kidney transplantation (LDKT) dominated transplant programme, kidney paired donation (KPD) may be a cost-effective and valid alternative strategy to increase LDKT in countries with limited resources where deceased donation kidney transplantation (DDKT) is in the initial stages. Here, we report our experience of 300 single-centre KPD transplantations to increase LDKT in India. Between January 2000 and July 2016, 3616 LDKT and 561 DDKT were performed at our transplantation centre, 300 (8.3%) using KPD. The reasons for joining KPD among transplanted patients were ABO incompatibility (n = 222), positive cross-match (n = 59) and better matching (n = 19). A total of 124 two-way (n = 248), 14 three-way (n = 42), one four-way (n = 4) and one six-way exchange (n = 6) yielded 300 KPD transplants. Death-censored graft and patient survival were 96% (n = 288) and 83.3% (n = 250), respectively. The mean serum creatinine was 1.3 mg/dl at a follow-up of 3 ± 3 years. We credit the success of our KPD programme to maintaining a registry of incompatible pairs, counselling on KPD, a high-volume LDKT programme and teamwork. KPD is legal, cost effective and rapidly growing for facilitating LDKT with incompatible donors. This study provides large-scale evidence for the expansion of single-centre LDKT via KPD when national programmes do not exist.

Outcomes of kidney paired donation transplants in relation to shipping and cold ischaemia time.

To assess the impact of shipping distance and cold ischaemia time (CIT) of shipped organs in a kidney paired donation (KPD) programme, we evaluated the outcomes of the initial 100 kidney transplants performed in the Australian KPD programme. In a 44-month period, 12 centres were involved in fifteen 2-way, twenty 3-way, one 4-way and one 6-way exchanges. Sixteen kidneys were transplanted at the same hospital (CIT 2.6 ± 0.6 h) and 84 required transport to the recipient hospital (CIT 6.8 ± 2.8 h). A spontaneous fall in serum creatinine by at least 10% within 24 h was observed in 85% of recipients, with no difference between nonshipped and shipped kidneys. There were two cases of transient delayed graft function requiring dialysis and patient and graft survival at 1 year were 99% and 97%, respectively. There was no difference in recipients of nonshipped compared with shipped kidneys with regard to serum creatinine at 1 month (mean difference (MD) 7.3 µmol/l, 95% CI -20.2 to 34.8, P = 0.59), 1-year graft survival (MD 3.9%, 95% CI -5.4 to 13.2, P = 0.41) or patient survival (MD -2.4%, 95% CI -10.0 to 5.2, P = 0.54). Despite prolonged CIT for interstate exchanges, the programme's decision to ship donor kidneys rather than the donor appears to be safe.

[Living kidney donation]. / Le donneur vivant de rein.

OBJECTIVES: To review ethical, legal and technical aspects of living kidney donor surgery. MATERIAL AND METHODS: An exhaustive systematic review of the scientific literature was performed in the Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of the following keywords: Donor nephrectomy; Kidney paired donation; Kidney transplantation; Laparoscopic nephrectomy; Living donor; Organs trafficking; Robotic assisted nephrectomy; Vaginal extraction. French legal documents have been reviewed using the government portal (http://www.legifrance.gouv.fr). Articles were selected according to methods, language of publication and relevance. A total of 6421 articles were identified; after careful selection, 161 publications were considered of interest and were eligible for our review. RESULTS: The ethical debate focuses on organ shortage, financial incentive, organ trafficking and the recent data suggesting a small but significant increase risk for late renal disease in donor population. Legal decisions aim to increase the number of kidneys available for donation, such as kidney-paired donation that faces several obstacles in France. Laparoscopic approach became widely used, while robotic-assisted donor nephrectomy failed to demonstrate improved outcome as compared with other minimal invasive techniques. CONCLUSION: Minimally invasive living donor nephrectomy aims to limit side effects in the donor without increasing the morbidity in this specific population of healthy persons; long term surveillance to prevent the onset of renal disease in mandatory.

Kidney paired donation: principles, protocols and programs.

Due to the ongoing shortage of deceased-donor organs, novel strategies to augment kidney transplantation rates through expanded living donation strategies have become essential. These include desensitization in antibody-incompatible transplants and kidney paired donation (KPD) programs. KPD enables kidney transplant candidates with willing but incompatible living donors to join a registry of other incompatible pairs in order to find potentially compatible transplant solutions. Given the significant immunologic barriers with fewer donor options, single-center or small KPD programs may be less successful in transplanting the more sensitized patients; the optimal solution for the difficult-to-match patient is access to more potential donors and large multicenter or national registries are essential. Multicenter KPD programs have become common in the last decade, and now represent one of the most promising opportunities to improve transplant rates. To maximize donor-recipient matching, and minimize immunologic risk, these multicenter KPD programs use sophisticated algorithms to identify optimal match potential, with simultaneous two-, three- or more complex multiway exchanges. The article focuses on the recent progresses in KPD and it also reviews some of the differences and commonalities across four different national KPD programs.

Four years of experience with the Australian kidney paired donation programme.

New approaches to increase kidney transplantation rates through expansion of live donor kidney transplantation have become necessary due to ongoing shortage of deceased donor organs. These strategies include desensitization in antibody-incompatible transplants to overcome the barrier of blood group incompatibility or human leucocyte antigen antibodies between recipient and donor and kidney paired donation (KPD) programmes. In KPD, a kidney transplant candidate with an incompatible live donor joins a registry of other incompatible pairs in order to find potentially compatible transplant solutions. To match the largest possible number of donor-recipient pairs while minimizing immunologic risk, KPD programmes use sophisticated algorithms to identify suitable matches with simultaneous two-way or more complex multi-way exchanges as well as including non-directed anonymous donors to start a chain of compatible transplantations. Because of the significant immunologic barriers when fewer donor options are available, the optimal solution for difficult-to-match, highly sensitized patients is access to more potential donors using large multi-centre or national KPD registries. This review focuses on the first 4 years of experience with the Australian multi-centre KPD programme that was established in October 2010.

Center-defined unacceptable HLA antigens facilitate transplants for sensitized patients in a multi-center kidney exchange program.

Multi-center kidney paired donation (KPD) is an exciting new transplant option that has not yet approached its full potential. One barrier to progress is accurate virtual crossmatching for KPD waitlists with many highly sensitized patients. Virtual crossmatch results from a large multi-center consortium, the National Kidney Registry (NKR), were analyzed to determine the effectiveness of flexible center-specific criteria for virtual crossmatching. Approximately two-thirds of the patients on the NKR waitlist are highly sensitized (>80% CPRA). These patients have antibodies against HLA-A (63%), HLA-B (66%), HLA-C (41%), HLA-DRB1 (60%), HLA-DRB3/4/5 (18-22%), HLA-DQB1 (54%) and HLA-DPB1 (26%). With donors typed for these loci before activation, 91% of virtual crossmatches accurately predicted an acceptable cell-based donor crossmatch. Failed virtual crossmatches were attributed to equivocal virtual crossmatches (46%), changes in HLA antibodies (21%), antibodies against HLA-DQA (6%), transcription errors (6%), suspected non-HLA antibodies (5%), allele-specific antibodies (1%) and unknown causes (15%). Some failed crossmatches could be prevented by modifiable factors such as more frequent assessment of HLA antibodies, DQA1 typing of donors and auditing data entry. Importantly, when transplant centers have flexibility to define crossmatch criteria, it is currently feasible to use virtual crossmatching for highly sensitized patients to reliably predict acceptable cell-based crossmatches.

Decision Making in Kidney Paired Donation Programs with Altruistic Donors.

In recent years, kidney paired donation (KPD) has been extended to include living non-directed or altruistic donors, in which an altruistic donor donates to the candidate of an incompatible donor-candidate pair with the understanding that the donor in that pair will further donate to the candidate of a second pair, and so on; such a process continues and thus forms an altruistic donor-initiated chain. In this paper, we propose a novel strategy to sequentially allocate the altruistic donor (or bridge donor) so as to maximize the expected utility; analogous to the way a computer plays chess, the idea is to evaluate different allocations for each altruistic donor (or bridge donor) by looking several moves ahead in a derived look-ahead search tree. Simulation studies are provided to illustrate and evaluate our proposed method.

Low-risk delisting strategy in highly sensitized patients without donor offers included in exchange donation programs. One single-center experience.

Donor exchange programs were designed to allocate organs for highly sensitized (HS) patients. The allocation algorithm differs slightly among countries and includes different strategies to improve access to transplants in HS patients. However, many HS patients with a calculated panel reactive of antibodies (cPRA) of 100 % remain on the waiting list for a long time. Some allocation algorithms assume immunological risk, including Imlifidase treatment, to increase the chance of transplantation in very HS patients. Here, we describe our unicenter experience of low-risk delisting strategy in 15 HS patients included in the Spanish donor exchange program without donor offers. After delisting, 7 out of 15 HS patients reduced the cPRA below 99.95 % and impacted the reduction of time on the waiting list (p = 0.01), where 5 out of 7 achieved transplantation. Within those HS that remained above 99.95 %, 1 out of 8 was transplanted. All the HS were transplanted with delisted DSA, and only one with DSA level rebounded early after transplantation. All HS transplanted after delisting maintain graft function. The transplant immunology laboratories are challenged to search intermediate risk assessment methods for delisting high HS patients.