Exchange donor program in kidney transplantation

The first 4-way liver paired exchange from an interdisciplinary collaboration between health care professionals and design economists

We report initial results of a liver paired exchange (LPE) program established at the Liver Transplant Institute at Inonu University through collaboration with design economists. Since June 2022, the program has been using a matching procedure that maximizes the number of living donor liver transplants (LDLTs) to the patients in the pool subject to the ethical framework and the logistical constraints of the program. In 1 4-way and 4 2-way exchanges, 12 LDLTs have been performed via LPE in 2022. The 4-way exchange, generated in the same match run with a 2-way exchange, is a first worldwide. This match run generated LDLTs for 6 patients, revealing the value of the capacity to carry out larger than 2-way exchanges. With only 2-way exchanges, only 4 of these patients would receive a LDLT. The number of LDLTs from LPE can be increased by developing the capacity to perform larger than 2-way exchanges in either high-volume centers or multicenter programs.

Increasing Kidney-Exchange Options Within the Existing Living Donor Pool With CIAT: A Pilot Implementation Study

Computerized integration of alternative transplantation programs (CIAT) is a kidney-exchange program that allows AB0- and/or HLA-incompatible allocation to difficult-to-match patients, thereby increasing their chances. Altruistic donors make this available for waiting list patients as well. Strict criteria were defined for selected highly-immunized (sHI) and long waiting (LW) candidates. For LW patients AB0i allocation was allowed. sHI patients were given priority and AB0i and/or CDC cross-match negative HLAi allocations were allowed. A local pilot was established between 2017 and 2022. CIAT results were assessed against all other transplant programs available. In the period studied there were 131 incompatible couples; CIAT transplanted the highest number of couples (35%), compared to the other programs. There were 55 sHI patients; CIAT transplanted as many sHI patients as the Acceptable Mismatch program (18%); Other programs contributed less. There were 69 LW patients; 53% received deceased donor transplantations, 20% were transplanted via CIAT. In total, 72 CIAT transplants were performed: 66 compatible, 5 AB0i and 1 both AB0i and HLAi. CIAT increased opportunities for difficult-to-match patients, not by increasing pool size, but through prioritization and allowing AB0i and "low risk" HLAi allocation. CIAT is a powerful addition to the limited number of programs available for difficult-to-match patients.

Kidney Paired Donation Chains Initiated by Deceased Donors

Introduction

Rather than generating 1 transplant by directly donating to a candidate on the waitlist, deceased donors (DDs) could achieve additional transplants by donating to a candidate in a kidney paired donation (KPD) pool, thereby, initiating a chain that ends with a living donor (LD) donating to a candidate on the waitlist. We model outcomes arising from various strategies that allow DDs to initiate KPD chains.

Methods

We base simulations on actual 2016 to 2017 US DD and waitlist data and use simulated KPD pools to model DD-initiated KPD chains. We also consider methods to assess and overcome the primary criticism of this approach, namely the potential to disadvantage blood type O-waitlisted candidates.

Results

Compared with shorter DD-initiated KPD chains, longer chains increase the number of KPD transplants by up to 5% and reduce the number of DDs allocated to the KPD pool by 25%. These strategies increase the overall number of blood type O transplants and make LDs available to candidates on the waitlist. Restricting allocation of blood type O DDs to require ending KPD chains with LD blood type O donations to the waitlist markedly reduces the number of KPD transplants achieved.

Conclusion

Allocating fewer than 3% of DD to initiate KPD chains could increase the number of kidney transplants by up to 290 annually. Such use of DDs allows additional transplantation of highly sensitized and blood type O KPD candidates. Collectively, patients of each blood type, including blood type O, would benefit from the proposed strategies.

Increasing transplantability in Brazil: time to discuss Kidney Paired Donation

Introduction:

Kidney transplantation (KT) is the best treatment for chronic kidney disease. In Brazil, there are currently more than 26 thousand patients on the waitlist. Kidney Paired Donation (KPD) offers an incompatible donor-recipient pair the possibility to exchange with another pair in the same situation, it is a strategy to raise the number of KT.

Discussion:

KPD ceased being merely an idea over 20 years ago. It currently accounts for 16.2% of living donors KT (LDKT) in the USA and 8% in Europe. The results are similar to other LDKT. It is a promising alternative especially for highly sensitized recipients, who tend to accumulate on the waitlist. KPD is not limited to developed countries, as excellent results were already published in India in 2014. In Guatemala, the first LDKT through KPD was performed in 2011. However, the practice remains limited to isolated cases in Latin America.

Conclusion:

KPD programs with different dimensions, acceptance rules and allocation criteria are being developed and expanded worldwide to meet the demands of patients. The rise in transplantability brought about by KPD mostly meets the needs of highly sensitized patients. The Brazilian transplant program is mature enough to accept the challenge of starting its KPD program, intended primarily to benefit patients who have a low probability of receiving a transplant from a deceased donor.

Deceased donors as nondirected donors in kidney paired donation

As proof of concept, we simulate a revised kidney allocation system that includes deceased donor (DD) kidneys as chain-initiating kidneys (DD-CIK) in a kidney paired donation pool (KPDP), and estimate potential increases in number of transplants. We consider chains of length 2 in which the DD-CIK gives to a candidate in the KPDP, and that candidate's incompatible donor donates to theDD waitlist. In simulations, we vary initial pool size, arrival rates of candidate/donor pairs and (living) nondirected donors (NDDs), and delay time from entry to the KPDP until a candidate is eligible to receive a DD-CIK. Using data on candidate/donor pairs and NDDs from the Alliance for Paired Kidney Donation, and the actual DDs from the Scientific Registry of Transplant Recipients (SRTR) data, simulations extend over 2 years. With an initial pool of 400, respective candidate and NDD arrival rates of 2 per day and 3 per month, and delay times for access to DD-CIK of 6 months or less, including DD-CIKs increases the number of transplants by at least 447 over 2 years, and greatly reduces waiting times of KPDP candidates. Potential effects on waitlist candidates are discussed as are policy and ethical issues.

Creating Options for Difficult-to-match Kidney Transplant Candidates

BACKGROUND

Most transplantation centers recognize a small patient population that unsuccessfully participates in all available, both living and deceased donor, transplantation programs for many years: the difficult-to-match patients. This population consists of highly immunized and/or ABO blood group O or B patients.

METHODS

To improve their chances, Computerized Integration of Alternative Transplantation programs (CIAT) were developed to integrate kidney paired donation, altruistic/unspecified donation, and ABO and HLA desensitization. To compare CIAT with reality, a simulation was performed, including all patients, donors, and pairs who participated in our programs in 2015-2016. Criteria for inclusion as difficult-to-match, selected-highly immunized (sHI) patient were as follows: virtual panel reactive antibody >85% and participating for 2 years in Eurotransplant Acceptable Mismatch program. sHI patients were given priority, and ABO blood group incompatible (ABOi) and/or HLA incompatible (HLAi) matching with donor-specific antigen-mean fluorescence intensity (MFI) <8000 were allowed. For long-waiting blood group O or B patients, ABOi matches were allowed.

RESULTS

In reality, 90 alternative program transplantations were carried out: 73 compatible, 16 ABOi, and 1 both ABOi and HLAi combination. Simulation with CIAT resulted in 95 hypothetical transplantations: 83 compatible (including 1 sHI) and 5 ABOi combinations. Eight sHI patients were matched: 1 compatible, 6 HLAi with donor-specific antigen-MFI <8000 (1 also ABOi), and 1 ABOi match. Six/eight combinations for sHI patients were complement-dependent cytotoxicity cross-match negative.

CONCLUSIONS

CIAT led to 8 times more matches for difficult-to-match sHI patients. This offers them better chances because of a more favorable MFI profile against the new donor. Besides, more ABO compatible matches were found for ABOi couples, while total number of transplantations was not hampered. Prioritizing difficult-to-match patients improves their chances without affecting the chances of regular patients.

KPDGUI: An interactive application for optimization and management of a virtual kidney paired donation program

BACKGROUND AND OBJECTIVES

The aim in kidney paired donation (KPD) is typically to maximize the number of transplants achieved through the exchange of donors in a pool comprising incompatible donor-candidate pairs and non-directed (or altruistic) donors. With many possible options in a KPD pool at any given time, the most appropriate set of exchanges cannot be determined by simple inspection. In practice, computer algorithms are used to determine the optimal set of exchanges to pursue. Here, we present our software application, KPDGUI (Kidney Paired Donation Graphical User Interface), for management and optimization of KPD programs.

METHODS

While proprietary software platforms for managing KPD programs exist to provide solutions to the standard KPD problem, our application implements newly investigated optimization criteria that account for uncertainty regarding the viability of selected transplants and arrange for fallback options in cases where potential exchanges cannot proceed, with intuitive resources for visualizing alternative optimization solutions.

RESULTS

We illustrate the advantage of accounting for uncertainty and arranging for fallback options in KPD using our application through a case study involving real data from a paired donation program, comparing solutions produced under different optimization criteria and algorithmic priorities.

CONCLUSIONS

KPDGUI is a flexible and powerful tool for offering decision support to clinicians and researchers on possible KPD transplant options to pursue under different user-specified optimization schemes.

An efficient algorithm to enumerate sets with fallbacks in a kidney paired donation program

Kidney paired donation is a partial solution to overcoming biological incompatibility preventing kidney transplants. A kidney paired donation (KPD) program consists of altruistic or non-directed donors (NDDs) and pairs, each of which comprises a candidate in need of a kidney transplant and her/his willing but incompatible donor. Potential transplants from NDDs or donors in pairs to compatible candidates in other pairs are determined by computer assessment, though various situations involving either the donor, candidate, or proposed transplant may lead to a potential transplant failing to proceed. A KPD program can be viewed as a directed graph with NDDs and pairs as vertices and potential transplants as edges, where failure probabilities are associated with each vertex and edge. Transplants are carried out in the form of directed cycles among pairs and directed paths initiated by NDDs, which we refer to respectively as cycles and chains. Previous research shows that selecting disjoint subgraphs with a view to creating fallback options when failures occur generates more realized transplants than optimal selection of disjoint chains and cycles. In this paper, we define such subgraphs, which are called locally relevant (LR) subgraphs, and present an efficient algorithm to enumerate all LR subgraphs. Its computational efficiency is significantly better than the previous, more restrictive, algorithms.

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.

Accounting for Fairness in a Two-Stage Stochastic Programming Model for Kidney Exchange Programs

Kidney exchange programs, which allow a potential living donor whose kidney is incompatible with his or her intended recipient to donate a kidney to another patient in return for a kidney that is compatible for their intended recipient, usually aims to maximize the number of possible kidney exchanges or the total utility of the program. However, the fairness of these exchanges is an issue that has often been ignored. In this paper, as a way to overcome the problems arising in previous studies, we take fairness to be the degree to which individual patient-donor pairs feel satisfied, rather than the extent to which the exchange increases social benefits. A kidney exchange has to occur on the basis of the value of the kidneys themselves because the process is similar to bartering. If the matched kidneys are not of the level expected by the patient-donor pairs involved, the match may break and the kidney exchange transplantation may fail. This study attempts to classify possible scenarios for such failures and incorporate these into a stochastic programming framework. We apply a two-stage stochastic programming method using total utility in the first stage and the sum of the penalties for failure in the second stage when an exceptional event occurs. Computational results are provided to demonstrate the improvement of the proposed model compared to that of previous deterministic models.

Effect of match-run frequencies on the number of transplants and waiting times in kidney exchange

Numerous kidney exchange (kidney paired donation [KPD]) registries in the United States have gradually shifted to high-frequency match-runs, raising the question of whether this harms the number of transplants. We conducted simulations using clinical data from 2 KPD registries-the Alliance for Paired Donation, which runs multihospital exchanges, and Methodist San Antonio, which runs single-center exchanges-to study how the frequency of match-runs impacts the number of transplants and the average waiting times. We simulate the options facing each of the 2 registries by repeated resampling from their historical pools of patient-donor pairs and nondirected donors, with arrival and departure rates corresponding to the historical data. We find that longer intervals between match-runs do not increase the total number of transplants, and that prioritizing highly sensitized patients is more effective than waiting longer between match-runs for transplanting highly sensitized patients. While we do not find that frequent match-runs result in fewer transplanted pairs, we do find that increasing arrival rates of new pairs improves both the fraction of transplanted pairs and waiting times.

Ethical and Logistical Issues Raised by the Advanced Donation Program "Pay It Forward" Scheme

The advanced donation program was proposed in 2014 to allow an individual to donate a kidney in order to provide a voucher for a kidney in the future for a particular loved one. In this article, we explore the logistical and ethical issues that such a program raises. We argue that such a program is ethical in principle but there are many logistical issues that need to be addressed to ensure that the actual program is fair to both those who do and do not participate in this program.

Valuing Sets of Potential Transplants in a Kidney Paired Donation Network

In kidney paired donation (KPD), incompatible donor-candidate pairs and non-directed (also known as altruistic) donors are pooled together with the aim of maximizing the total utility of transplants realized via donor exchanges. We consider a setting in which disjoint sets of potential transplants are selected at regular intervals, with fallback options available within each proposed set in the case of individual donor, candidate or match failure. We develop methods for calculating the expected utility for such sets under a realistic probability model for the KPD. Exact expected utility calculations for these sets are compared to estimates based on Monte Carlo samples of the underlying network. Models and methods are extended to include transplant candidates who join KPD with more than one incompatible donor. Microsimulations demonstrate the superiority of accounting for failure probability and fallback options, as well as candidates joining with additional donors, in terms of realized transplants and waiting time for candidates.

A Look-Ahead Strategy for Non-Directed Donors in Kidney Paired Donation

While there is a growing need for kidney transplants to treat end stage kidney disease, the supply of transplantable kidneys is in serious shortage. Kidney paired donation (KPD) programs serve as platforms for candidates with willing but incompatible donors to assess the possibility of exchanging donors, thus opening up new transplant opportunities for these candidates. In recent years, non-directed (or altruistic) donors (NDDs) have been incorporated into KPD programs beginning chains of transplants that benefit many candidates. In such programs, making optimal decisions in transplant exchange selection is of critical importance. With the aim of improving the selection of chains beginning with an NDD, this paper introduces a look-ahead multiple decision strategy to select chains, that are easy to extend in the future. Simulation studies are adopted to assess performance of this strategy. Taking into account the extensibility of chains increases the number of realized transplants.

Donor and Recipient Perspectives on Anonymity in Kidney Donation From Live Donors: A Multicenter Survey Study

BACKGROUND

Maintaining anonymity is a requirement in the Netherlands and Sweden for kidney donation from live donors in the context of nondirected (or unspecified) and paired exchange (or specified indirect) donation. Despite this policy, some donors and recipients express the desire to know one another. Little empirical evidence informs the debate on anonymity. This study explored the experiences, preferences, and attitudes of donors and recipients toward anonymity.

STUDY DESIGN

Retrospective observational multicenter study using both qualitative and quantitative methods.

SETTING & PARTICIPANTS

414 participants from Dutch and Swedish transplantation centers who received or donated a kidney anonymously (nondirected or paired exchange) completed a questionnaire about anonymity. Participation was a median of 31 months after surgery.

FACTORS

Country of residence, donor/recipient status, transplant type, time since surgery.

OUTCOMES

Experiences, preferences, and attitudes toward anonymity.

RESULTS

Most participants were satisfied with their experience of anonymity before and after surgery. A minority would have liked to have met the other party before (donors, 7%; recipients, 15%) or after (donors, 22%; recipients, 31%) surgery. Significantly more recipients than donors wanted to meet the other party. Most study participants were open to meeting the other party if the desire was mutual (donors, 58%; recipients, 60%). Donors agree significantly more with the principle of anonymity before and after surgery than recipients. Donors and recipients thought that if both parties agreed, it should be permissible to meet before or after surgery. There were few associations between country or time since surgery and experiences or attitudes. The pros and cons of anonymity reported by participants were clustered into relational and emotional, ethical, and practical and logistical domains.

LIMITATIONS

The relatively low response rate of recipients may have reduced generalizability. Recall bias was possible given the time lag between transplantation and data collection.

CONCLUSIONS

This exploratory study illustrated that although donors and recipients were usually satisfied with anonymity, the majority viewed a strict policy on anonymity as unnecessary. These results may inform policy and education on anonymity.

Broken Chains and Reneging: A Review of 1748 Kidney Paired Donation Transplants

Concerns regarding the potential for broken chains and "reneges" within kidney paired donation (KPD) and its effect on chain length have been raised previously. Although these concerns have been tested in simulation studies, real-world data have yet to be evaluated. The purpose of this study was to evaluate the actual rate and causes of broken chains within a large KPD program. All patients undergoing renal transplantation through the National Kidney Registry from 2008 through May 2016 were included for analysis. Broken chains and loops were identified. A total of 344 chains and 78 loops were completed during the study period, yielding a total of 1748 transplants. Twenty broken chains and one broken loop were identified. The mean chain length (number of transplants) within broken chains was 4.8 compared with 4.6 of completed chains (p = 0.78). The most common causes of a broken chain were donor medical issues incurred while acting as a bridge donor (n = 8), donors electing not to proceed (n = 6), and kidneys being declined by the recipient surgeon (n = 4). All recipients involved in a broken chain subsequently received a transplant. Based on the results, broken chains are infrequent, are rarely due to lack of donor motivation, and have no significant impact on chain length.

A Kidney Graft Survival Calculator that Accounts for Mismatches in Age, Sex, HLA, and Body Size

BACKGROUND AND OBJECTIVES

Outcomes for transplants from living unrelated donors are of particular interest in kidney paired donation (KPD) programs where exchanges can be arranged between incompatible donor-recipient pairs or chains created from nondirected/altruistic donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using Scientific Registry of Transplant Recipients data, we analyzed 232,705 recipients of kidney-alone transplants from 1998 to 2012. Graft failure rates were estimated using Cox models for recipients of kidney transplants from living unrelated, living related, and deceased donors. Models were adjusted for year of transplant and donor and recipient characteristics, with particular attention to mismatches in age, sex, human leukocyte antigens (HLA), body size, and weight.

RESULTS

The dependence of graft failure on increasing donor age was less pronounced for living-donor than for deceased-donor transplants. Male donor-to-male recipient transplants had lower graft failure, particularly better than female to male (5%-13% lower risk). HLA mismatch was important in all donor types. Obesity of both the recipient (8%-18% higher risk) and donor (5%-11% higher risk) was associated with higher graft loss, as were donor-recipient weight ratios of <75%, compared with transplants where both parties were of similar weight (9%-12% higher risk). These models are used to create a calculator of estimated graft survival for living donors.

CONCLUSIONS

This calculator provides useful information to donors, candidates, and physicians of estimated outcomes and potentially in allowing candidates to choose among several living donors. It may also help inform candidates with compatible donors on the advisability of joining a KPD program.

Kidney Exchange to Overcome Financial Barriers to Kidney Transplantation

Organ shortage is the major limitation to kidney transplantation in the developed world. Conversely, millions of patients in the developing world with end-stage renal disease die because they cannot afford renal replacement therapy-even when willing living kidney donors exist. This juxtaposition between countries with funds but no available kidneys and those with available kidneys but no funds prompts us to propose an exchange program using each nation's unique assets. Our proposal leverages the cost savings achieved through earlier transplantation over dialysis to fund the cost of kidney exchange between developed-world patient-donor pairs with immunological barriers and developing-world patient-donor pairs with financial barriers. By making developed-world health care available to impoverished patients in the developing world, we replace unethical transplant tourism with global kidney exchange-a modality equally benefitting rich and poor. We report the 1-year experience of an initial Filipino pair, whose recipient was transplanted in the United states with an American donor's kidney at no cost to him. The Filipino donor donated to an American in the United States through a kidney exchange chain. Follow-up care and medications in the Philippines were supported by funds from the United States. We show that the logistical obstacles in this approach, although considerable, are surmountable.

Attitudes of Lay Stakeholders and Transplant Professionals About Disclosure to Living Kidney Donors in Exchanges and Chains

Background:

Current policies require very limited informational disclosure between living kidney donors and recipients regardless of the relationship type. No specific policies exist to suggest that exchange/chain donors and their recipients should be treated differently. We surveyed transplant professionals (surgeons and nephrologists) and members of the National Kidney Foundation (NKF) to determine their support for disclosing to donors the health, health behavior, and social information of their exchange/chain donors and exchange/chain recipients.

Methods:

Twenty questions regarding disclosing to donors information about both their exchange/chain donors and exchange/chain recipients were included in 2 larger surveys on disclosure about kidney transplantation. Survey A was sent electronically to NKF list-servs, and survey B was sent to transplant professionals both electronically and by postal mail.

Results:

Survey A yielded 236 valid surveys from NKF donors and recipients (lay stakeholders). Survey B yielded 111 valid surveys from transplant professionals. Both sets of stakeholders support disclosing to donors some health and health behavior information of their exchange/chain donor and exchange/chain recipient, and mostly oppose disclosure of social information. Lay stakeholders favored disclosing significantly more information than transplant professionals. Among lay stakeholders, donor respondents were more supportive than recipient respondents in disclosing to donors health information about the exchange/chain recipient. Among transplant professionals, surgeons were more supportive than nephrologists in disclosing to donors information about the exchange/chain recipient that may impact graft survival.

Conclusions:

There is broad stakeholder support for disclosing some health and health behavior information to donors about their exchange/chain donors and recipients.

Planning for Uncertainty and Fallbacks Can Increase the Number of Transplants in a Kidney-Paired Donation Program

A kidney-paired donation (KPD) pool consists of transplant candidates and their incompatible donors, along with nondirected donors (NDDs). In a match run, exchanges are arranged among pairs in the pool via cycles, as well as chains created from NDDs. A problem of importance is how to arrange cycles and chains to optimize the number of transplants. We outline and examine, through example and by simulation, four schemes for selecting potential matches in a realistic model of a KPD system; proposed schemes take account of probabilities that chosen transplants may not be completed as well as allowing for contingency plans when the optimal solution fails. Using data on candidate/donor pairs and NDDs from the Alliance for Paired Donation, the simulations extend over 8 match runs, with 30 pairs and 1 NDD added between each run. Schemes that incorporate uncertainties and fallbacks into the selection process yield substantially more transplants on average, increasing the number of transplants by as much as 40% compared to a standard selection scheme. The gain depends on the degree of uncertainty in the system. The proposed approaches can be easily implemented and provide substantial advantages over current KPD matching algorithms.

Features and ethical considerations associated with living kidney and liver transplantations in South Korea

When the Organ Transplantation Act came into effect in 2000 in South Korea, living organ donations were legalized and the Korean Network for Organ Sharing (KONOS) had a duty to approve the application of donation. The number of living organ donors has increased and the waiting time of recipients has been steady or decreased. The Organ Transplantation Act mainly focuses on the informed consent process of donations, so unrelated directed donations are permitted unless there is a suspicion of organ trafficking. But the annual reports show that directed donations of unrelated and related donors may have an ethical concern about organ sales. The donations of family members show another ethical concern. The numbers of ABO-incompatible transplantations have steadily increased since 2008, and lineal descendants, including minors, comprised 61% of living liver donors in 2012. Addressing the unethical practices without inhibiting living organ donations is the current task in South Korea. Private agencies have actively operated the living organ donations programs. The web-based computerized organ exchange program has been cooperatively run by hospital-based organizations. The strict legal regulations that could decrease living organ donations are hard to adopt. In the current situation, the functions of the official system need to be more developed. A national organ exchange program run by KONOS could be an option which could reduce ABO-incompatible transplantations and relieve the ethical concern of organ sales in unrelated directed donations.

Alternative Living Kidney Donation Programs Boost Genetically Unrelated Donation

Donor-recipient ABO and/or HLA incompatibility used to lead to donor decline. Development of alternative transplantation programs enabled transplantation of incompatible couples. How did that influence couple characteristics? Between 2000 and 2014, 1232 living donor transplantations have been performed. In conventional and ABO-incompatible transplantation the willing donor becomes an actual donor for the intended recipient. In kidney-exchange and domino-donation the donor donates indirectly to the intended recipient. The relationship between the donor and intended recipient was studied. There were 935 conventional and 297 alternative program transplantations. There were 66 ABO-incompatible, 68 domino-paired, 62 kidney-exchange, and 104 altruistic donor transplantations. Waiting list recipients (n = 101) were excluded as they did not bring a living donor. 1131 couples remained of whom 196 participated in alternative programs. Genetically unrelated donors (486) were primarily partners. Genetically related donors (645) were siblings, parents, children, and others. Compared to genetically related couples, almost three times as many genetically unrelated couples were incompatible and participated in alternative programs (P < 0.001). 62% of couples were genetically related in the conventional donation program versus 32% in alternative programs (P < 0.001). Patient and graft survival were not significantly different between recipient programs. Alternative donation programs increase the number of transplantations by enabling genetically unrelated donors to donate.

The Canadian kidney paired donation program: a national program to increase living donor transplantation

BACKGROUND

Establishment of a national kidney paired donation (KPD) program represents a unique achievement in Canada's provincially organized health care system.

METHODS

Key factors enabling program implementation included consultation with international experts, formation of a unique organization with a mandate to facilitate interprovincial collaboration, and the volunteer efforts of members of the Canadian transplant community to overcome a variety of logistical barriers.

RESULTS

As of December 2013, the program had facilitated 240 transplantations including 10% with Calculated panel reactive antibody (cPRA) ≥97%. Unique features of the Canadian KPD program include participation of n = 55 nondirected donors, performance of only donor specific antibody negative transplants, the requirement for donor travel, and nonuse of bridge donors.

CONCLUSION

The national KPD program has helped maintain the volume of living kidney donor transplants in Canada over the past 5 years and serves as a model of inter-provincial collaboration to improve the delivery of health care to Canadians.

More than 300 consecutive living donor liver transplants a year at a single center

BACKGROUND

Living donor liver transplantation (LDLT) has been the first option for the patients requiring liver transplantation in East Asia because of the scarcity of cadaveric grafts. We have performed consecutively more than 300 LDLTs per year, and herein report our methods.

METHODS

In 1997, the first successful adult LDLTs used a left and subsequently a right lobe. However, congestion in the anterior segment of right-lobe grafts prompted us to initiate reconstruction of middle hepatic venous tributaries in 1998. Dual LDLT grafts using 2 left lobes were developed in 2000 to solve graft-size insufficiency and minimize donor risk. The indications for adult LDLT were broadened to near complete obstruction of the portal vein by application of intraoperative cine-portography and portal vein stenting in 2004. ABO-incompatible adult LDLT was initiated in 2008 to overcome the blood group barrier between recipient and donor.

RESULTS

With various innovations at our institution, 317 LDLTs were performed yearly in 2010 and 2011: 301 in 2010 and 298 in 2011. The most common primary diseases was hepatitis B virus-related liver cirrhosis with or without hepatocellular carcinoma (64.3%). The most common graft types were right hemiliver (82.6%). There has been no donor mortality. ABO-incompatible LDLT cases were 11.0% of the total. In-hospital mortality in 2011 was 2.5% (n = 8; adult 6, pediatric 2).

CONCLUSION

Innovations in operative techniques and perioperative care as well as dedicated team members have made it possible to perform more than 300 LDLTs per year consecutively with excellent outcomes.

Toward more than 400 liver transplantations a year at a single center

BACKGROUND

For the first time at Asan Medical Center (AMC) we performed more than 400 liver transplantations (LTs) per year in 2011, despite same number of living donor liver transplantations (LDLTs).

METHODS

Our OLT program was started in 1992, but not activated well due to the scarcity of deceased donor organs. Since adult LDLTs using a left lobe and then a right lobe were successfully performed in 1997, we have developed several innovative techniques and approaches for adult LDLT, for example, modified right-lobe graft reconstructing middle hepatic branches in 1998, dual graft LDLT using 2 left lobes in 2000; new criteria for hepatocellular carcinoma (HCC); as well as ABO-incompatible LDLT, the first in the world. As a result, the number of LDLTs has increased rapidly but reached a plateau recently. Nationwide efforts to promote deceased donation increased the number of deceased donor liver transplantation (DDLT).

RESULTS

We have performed 317 LDLTs per year in 2010 and 2011, respectively. The number of LTs reached 403 in 2011. This large number was possible due to a remarkable increase of DDLTs from 50 in 2010 to 86 in 2011. Seventy-nine patients (68.1%) among 116 patients (28.8%) required an urgent LT receiving a DDLT. LT for HCC or ABO-mismatch comprised 50.3% (n = 150) or 8.7% (n = 35), respectively. In-hospital mortality rate in 2011 was 4.7%.

CONCLUSIONS

The increased LTs number at AMC was aided by the nationwide campaign.

Coordinating unspecified living kidney donation and transplantation across the blood-type barrier in kidney exchange

BACKGROUND

This article studies multicenter coordination of unspecified living kidney donation and transplantation across the blood-type barrier in kidney exchange. Important questions are whether such coordination should use domino paired donation or non simultaneous extended altruistic donor chains, what the length of the segments in such chains should be, when they should be terminated, and how much time should be allowed between matching rounds. Furthermore, it is controversial whether the different modalities should be coordinated centrally or locally and independently.

METHODS

Kidney exchange policies are simulated using actual data from the Dutch national kidney exchange program. Sensitivity analysis is performed on the composition of the population, the time unspecified and bridge donors wait before donating to the wait list, the time between matching rounds, and donor renege rates.

RESULTS

Central coordination of unspecified donation and transplantation across the blood-type barrier can increase transplants by 10% (PG0.001). Especially highly sensitized and blood type O patients benefit. Sufficient time between matching rounds is essential: three-monthly exchanges result in 31% more transplants than weekly exchanges. Benefits of non simultaneous extended altruistic donor chains are limited in case of low numbers of highly sensitized patients and sufficient unspecified donors. Chains are best terminated when no further segment is part of an optimal exchange within 3 months.

CONCLUSIONS

There is clear synergy in the central coordination of both unspecified donation and transplantation across the blood-type barrier in kidney exchange. The best configuration of a national program depends on the composition of the patient Y donor population.

Optimal Decisions for Organ Exchanges in a Kidney Paired Donation Program

The traditional concept of barter exchange in economics has been extended in the modern era to the area of living-donor kidney transplantation, where one incompatible donor-candidate pair is matched to another pair with a complementary incompatibility, such that the donor from one pair gives an organ to a compatible candidate in the other pair and vice versa. Kidney paired donation (KPD) programs provide a unique and important platform for living incompatible donor-candidate pairs to exchange organs in order to achieve mutual benefit. In this paper, we propose novel organ allocation strategies to arrange kidney exchanges under uncertainties with advantages, including (i) allowance for a general utility-based evaluation of potential kidney transplants and an explicit consideration of stochastic features inherent in a KPD program; and (ii) exploitation of possible alternative exchanges when the originally planned allocation cannot be fully executed. This allocation strategy is implemented using an integer programming (IP) formulation, and its implication is assessed via a data-based simulation system by tracking an evolving KPD program over a series of match runs. Extensive simulation studies are provided to illustrate our proposed approach.

Controversies in kidney paired donation

Kidney paired donation represented 10% of living kidney donation in the United States in 2011. National registries around the world and several separate registries in the United States arrange paired donations, although with significant variations in their practices. Concerns about ethical considerations, clinical advisability, and the quantitative effectiveness of these approaches in paired donation result in these variations. For instance, although donor travel can be burdensome and might discourage paired donation, it was nearly universal until convincing analysis showed that living donor kidneys can sustain many hours of cold ischemia time without adverse consequences. Opinions also differ about whether the last donor in a chain of paired donation transplants initiated by a nondirected donor should donate immediately to someone on the deceased donor wait-list (a domino or closed chain) or should be asked to wait some length of time and donate to start another sequence of paired donations later (an open chain); some argue that asking the donor to donate later may be coercive, and others focus on balancing the probability that the waiting donor withdraws versus the number of additional transplants if the chain can be continued. Other controversies in paired donation include simultaneous versus nonsimultaneous donor operations, whether to enroll compatible pairs, and interactions with desensitization protocols. Efforts to expand public awareness of and participation in paired donation are needed to generate more transplant opportunities.

Nonsimultaneous chains and dominos in kidney- paired donation-revisited

Since 2008, kidney exchange in America has grown in part from the incorporation of nondirected donors in transplant chains rather than simple exchanges. It is controversial whether these chains should be performed simultaneously 'domino-paired donation', (DPD) or nonsimultaneously 'nonsimultaneous extended altruistic donor, chains (NEAD). NEAD chains create 'bridge donors' whose incompatible recipients receive kidneys before the bridge donor donates, and so risk reneging by bridge donors, but offer the opportunity to create more transplants by overcoming logistical barriers inherent in simultaneous chains. Gentry et al. simulated whether DPD or NEAD chains would produce more transplants when chain segment length was limited to three transplants, and reported that DPD performed at least as well as NEAD chains. As this finding contrasts with the experience of several groups involved in kidney-paired donation, we performed simulations that allowed for longer chain segments and used actual patient data from the Alliance for Paired Donation. When chain segments of 4-6 transplants are allowed in the simulations, NEAD chains produce more transplants than DPD. Our simulations showed not only more transplants as chain length increased, but also that NEAD chains produced more transplants for highly sensitized and blood type O recipients.

Donor exchange programs in kidney transplantation: rationale and operational details from the north central donor exchange cooperative

The increasing need for kidney transplants has led to innovations such as donor exchange programs. These programs offer transplant recipients with incompatible donors an opportunity to receive a compatible kidney. They also provide an alternative to costly desensitization protocols that have unproven long-term outcomes. Donor exchange programs have multiple options, including simple 2-pair exchanges, more complicated domino exchanges, or chain donations. The United States currently is limited by regional programs that provide for kidney donor exchanges. However, with the increasing public interest in and need for kidney transplants, general nephrologists will be approached with questions about these donor exchange programs. The goal of this review is to discuss donor exchange programs, including their role in expanding the donor pool, various types of exchanges, regional centers that provide these programs, and the process involved in patient enrollment. General knowledge of donor exchange programs will help providers in discussing options with patients approaching end-stage kidney disease and transplant.

Paired donor interchange to avoid ABO-incompatible living donor liver transplantation

We report an emergency paired donor interchange living donor liver transplant performed on January 13, 2009. The 4 operations (2 liver transplants) were performed simultaneously. The aim was to avoid 2 ABO-incompatible liver transplants. One recipient in acute liver failure underwent transplantation in a high-urgency situation. The abdomen of the other recipient had severe adhesions from previous spontaneous bacterial peritonitis that rendered the recipient operation almost impossible. The ethical and logistical issues are discussed. Approaches adopted in anticipation of potential adverse outcomes are explained in view of the higher donor and recipient mortality and morbidity rates in comparison with kidney transplantation.

Incentive compatibility in kidney exchange problems

The problem of kidney exchanges shares common features with the classical problem of exchange of indivisible goods studied in the mechanism design literature, while presenting additional constraints on the size of feasible exchanges. The solution of a kidney exchange problem can be summarized in a mapping from the relevant underlying characteristics of the players (patients and their donors) to the set of matchings. The goal is to select only matchings maximizing a chosen welfare function. Since the final outcome heavily depends on the private information in possess of the players, a basic requirement in order to reach efficiency is the truthful revelation of this information. We show that for the kidney exchange problem, a class of (in principle) efficient mechanisms does not enjoy the incentive compatibility property and therefore is subject to possible manipulations made by the players in order to profit of the misrepresentation of their private information.

Clinical outcomes of multicenter domino kidney paired donation

Domino kidney paired donation (KPD) is a method by which an altruistic living nondirected donor (LND) is allocated to a pool of incompatible donor-recipient pairs (DRP) and a series of KPDs is initiated. To evaluate the feasibility and clinical outcomes of multicenter domino KPD, we retrospectively analyzed a cohort of DRPs who underwent domino KPD between February 2001 and July 2007 at one of 16 transplant centers. One hundred seventy-nine kidney transplants were performed, with 70 domino chains initiated by altruistic LND. There were 45 two-pair chains, 15 three-pair chains, 7 four-pair chains, 2 five-pair chains and 1 six-pair chain. A majority of donors were spouses (47.5%) or altruistic LNDs (39.1%). DRPs with a blood type O recipient or an AB donor comprised 45.9% of transplanted DRPs. HLA mismatch improved in transplanted donors compared to intended donors in pairs enrolled to improve HLA mismatch (3.4 +/- 0.7 vs. 4.8 +/- 1.0, p < 0.001). One-year and 5-year graft survival rates were 98.3% and 87.7%, respectively, with a median follow-up of 46 months. One-year and 5-year patient survival rates were 97.2% and 90.8%, respectively. In conclusion, multicenter domino KPD could multiply the benefits of donation from LNDs, with patients and graft survival rates comparable to those seen with conventional KPD.

Asynchronous, out-of-sequence, transcontinental chain kidney transplantation: a novel concept

The organ donor shortage has been the most important hindrance in getting listed patients transplanted. Living kidney donors who are incompatible with their intended recipients are an untapped resource for expanding the donor pool through participation in transplant exchanges. Chain transplantation takes this concept further, with the potential to benefit even more recipients. We describe the first asynchronous, out of sequence transplant chain that was initiated by transcontinental shipment of an altruistic donor kidney 1 week after that recipient's incompatible donor had already donated his kidney to the next recipient in the chain. The altruistic donor kidney was transported from New York to Los Angeles and functioned immediately after transplantation. Our modified-sequence asynchronous transplant chain (MATCH) enabled eight recipients, at four different institutions, to benefit from the generosity of one altruistic donor and warrants further exploration as a promising step toward addressing the organ donor shortage.

Successful expansion of the living donor pool by alternative living donation programs

Between January 2000 and December 2007, 786 potential recipients and 1059 potential donors attended our pretransplant unit with the request for a living-donor renal transplant procedure. The recipients brought one potential donor in 77.2% and two or more donors in 22.8% of cases. In the regular living donor program, a compatible donor was found for 467 recipients. Without considering alternative donation, 579 donors would have been refused. Alternative living donation programs led to 114 compatible combinations: kidney-exchange program (35), ABO-incompatible donation (25), anonymous donation (37) and domino-paired anonymous donation (17). Together, the 114 alternative program donations and the 467 regular living donations led to 581 living donor transplantations (24.4% increase). Eventually for 54.9% (581/1059) of our donors, a compatible combination was found. Donor-recipient incompatibility comprised 19.4% (89/458) in the final refused population, which is 8.8% of the potential donor-recipient couples. Without considering alternative donation, 30.1% (174/579) of the refused donors would have been refused on incompatibility and 6.4% (37/579) because they were anonymous. This is 20% of the potential donor population (211/1059). The implementation of alternative living donation programs led to a significant increase in the number of transplantations, while transplantations via the direct donation program steadily increased.

The roles of dominos and nonsimultaneous chains in kidney paired donation

Efforts to expand kidney paired donation have included matching nondirected donors (NDDs) to incompatible pairs. In domino paired donation (DPD), an NDD gives to the recipient of an incompatible pair, beginning a string of simultaneous transplants that ends with a living donor giving to a recipient on the deceased donor waitlist. Recently, nonsimultaneous extended altruistic donor (NEAD) chains were introduced. In a NEAD chain, the last donor of the string of transplants initiated by an NDD is reserved to donate at a later time. Our aim was to project the impact of each of these strategies over 2 years of operation for paired donation programs that also allocate a given number of NDDs. Each NDD facilitated an average of 1.99 transplants using DPD versus 1.90 transplants using NEAD chains (p = 0.3), or 1.0 transplants donating directly to the waitlist (p < 0.001). NEAD chains did not yield more transplants compared with simultaneous DPD. Both DPD and NEAD chains relax reciprocality requirements and rebalance the blood-type distribution of donors. Because traditional paired donation will leave many incompatible pairs unmatched, novel approaches like DPD and NEAD chains must be explored if paired donation programs are to help a greater number of people.

A nonsimultaneous, extended, altruistic-donor chain

We report a chain of 10 kidney transplantations, initiated in July 2007 by a single altruistic donor (i.e., a donor without a designated recipient) and coordinated over a period of 8 months by two large paired-donation registries. These transplantations involved six transplantation centers in five states. In the case of five of the transplantations, the donors and their coregistered recipients underwent surgery simultaneously. In the other five cases, "bridge donors" continued the chain as many as 5 months after the coregistered recipients in their own pairs had received transplants. This report of a chain of paired kidney donations, in which the transplantations were not necessarily performed simultaneously, illustrates the potential of this strategy.