The honeymoon phase and studies of nonsimultaneous chains in kidney-paired donation

Recipient Outcomes From Nondirected Live Kidney Donors: A UK-based Cohort Study

Background

Increasing numbers of patients with end-stage renal failure are receiving kidneys from nondirected kidney donors (NKDs), also known as altruistic donors. Transplant outcomes for recipients of such kidneys are largely inferred from studies on specified kidney donors (SKDs), which may be inaccurate due to differences in donor, recipient and transplant specific factors. We report the outcomes for recipients of NKD in the United Kingdom.

Methods

Outcomes for 6861 patients receiving a living donor kidney transplant between January 2007 and December 2014 were analyzed using both the National Health Service Blood and Transplant and the UK Renal Registry datasets. Graft and patient outcomes were compared for patients receiving NKD and SKD organs using univariable and multivariable analyses.

Results

There was significant discordance between the NKD and SKD donors and recipients. These included increased donor age (median, 58 years vs 47 years; P < 0.001) and higher rates of hemodialysis and previous transplants in the NKD group (both P < 0.001). Despite such markers of increased risk among both donors and recipients of NKD kidneys, there was no difference in graft survival on univariable (hazard ratio, 1.20; 95% confidence interval, 0.77-1.86; P = 0.419) or multivariable analysis (hazard ratio, 1.13; 95% confidence interval, 0.65-1.95; P = 0.665).

Conclusions

Despite some markers of transplant complexity, nondirected kidney donor organs are an excellent source of organs for transplantation.

Seventy-seven kidney paired donation transplantations at a single transplant centre in India led to an increase in living donor kidney transplantations in 2015

Background

To ascertain the validity of kidney paired donations (KPDs) as an alternative strategy for increasing living donor kidney transplantations (LDKTs) in an LDKT-dominated transplant programme since directed kidney transplantation, ABO-incompatible or crossmatch-positive pairs are not feasible due to costs and infectious complications.

Methods

This was a prospective single-centre study of 77 KPD transplantations (25 two-way, 7 three-way and 1 six-way exchange) from 1 January 2015 to 1 January 2016 of 158 registered donor recipient pairs. During this period, a total of 380 kidney transplantations [71 deceased donor kidney transplantations (DDKTs), 309 LDKTs] were performed. The reasons for opting for KPD were ABO incompatibility (n = 45), sensitization (n = 26) and better matching (n = 6).

Results

KPD matching was facilitated in 62% (n = 98) of transplants. In all, 48.7% (n = 77) of the transplants were completed in 2015, whereas 13.3% (n = 21) of the matched patients were to undergo transplant surgery in early 2016 after getting legal permission. The waiting time for KPD was shorter compared with DDKT. The death-censored graft survival and patient survival were 98.7% (n = 76) and 93.5% (n = 72), respectively. In all, 14.2% (n = 11) of patients had acute rejection. Match rates among sensitized (n = 60) and O group patients (n = 62) were 58.3% (n = 35) and 41.9% (n = 26), respectively. Of these, 43.3% (n = 26) and 29% (n = 18) of transplants were completed and 15% (n = 9) and 12.9% (n = 8), respectively, are waiting for legal permission.

Conclusions

LDKT increased by 25% in 1 year in our single-centre KPD programme. Our key to success was the formation of a KPD registry, awareness and active counselling programs and developing a dedicated team.

Six end-stage renal disease patients benefited from first non-simultaneous single center 6-way kidney exchange transplantation in India

AIM

To avoid desensitization protocols and ABO incompatible kidney transplantation (KT) due to high costs and increased risk of infections from intense immunosuppression.

METHODS

We present institutional ethical review board - approved study of single center 6-way kidney exchange transplantation. The participants comprised ABO incompatibility (n = 1); positive cross-match and/or presence of donor specific antibody (n = 5). The average time required from registration in kidney paired donation (KPD) registry to find suitable donors was 45 d and time required to perform transplants after legal permission was 2 mo.

RESULTS

Graft and patient survival were 100%, and 100%, respectively. One patient had biopsy-proven acute borderline T cell rejection (Banff update 2013, type 3). Mean serum creatinine was 0.8 mg/dL at 9 mo follow-up. The waiting time in KPD was short as compared to deceased donor KT.

CONCLUSION

We report first non-simultaneous, single center, 6-way kidney exchange transplantation from India. Our experience will encourage other centers in India to undertake this practice.

Historical Matching Strategies in Kidney Paired Donation: The 7-Year Evolution of a Web-Based Virtual Matching System

Failure to convert computer-identified possible kidney paired donation (KPD) exchanges into transplants has prohibited KPD from reaching its full potential. This study analyzes the progress of exchanges in moving from "offers" to completed transplants. Offers were divided into individual segments called 1-way transplants in order to calculate success rates. From 2007 to 2014, the Alliance for Paired Donation performed 243 transplants, 31 in collaboration with other KPD registries and 194 independently. Sixty-one of 194 independent transplants (31.4%) occurred via cycles, while the remaining 133 (68.6%) resulted from nonsimultaneous extended altruistic donor (NEAD) chains. Thirteen of 35 (37.1%) NEAD chains with at least three NEAD segments accounted for 68% of chain transplants (8.6 tx/chain). The "offer" and 1-way success rates were 21.9 and 15.5%, respectively. Three reasons for failure were found that could be prospectively prevented by changes in protocol or software: positive laboratory crossmatch (28%), transplant center declined donor (17%) and pair transplanted outside APD (14%). Performing a root cause analysis on failures in moving from offer to transplant has allowed the APD to improve protocols and software. These changes have improved the success rate and the number of transplants performed per year.

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.

Allocation and matching in kidney exchange programs

Living donor kidney transplantation is the preferred treatment for patients suffering from end-stage renal disease. To alleviate the shortage of kidney donors, many advances have been made to improve the utilization of living donors deemed incompatible with their intended recipient. The most prominent of these advances is kidney paired donation (KPD), which matches incompatible patient-donor pairs to facilitate a kidney exchange. This review discusses the various approaches to matching and allocation in KPD. In particular, it focuses on the underlying principles of matching and allocation approaches, the combination of KPD with other strategies such as ABO incompatible transplantation, the organization of KPD, and important future challenges. As the transplant community strives to balance quantity and equity of transplants to achieve the best possible outcomes, determining the right long-term allocation strategy becomes increasingly important. In this light, challenges include making full use of the various modalities that are now available through integrated and optimized matching software, encouragement of transplant centers to fully participate, improving transplant rates by focusing on the expected long-run number of transplants, and selecting uniform allocation criteria to facilitate international pools.

Unspecified kidney donation--a review of principles, practice and potential

Unspecified kidney donation is an emerging resource to bridge the gap between supply and demand of kidneys for transplantation. However, uncertainty remains among both the transplantation community and lay public with regard to the intention, motivation, and legitimacy of such donors. Even within programs that use unspecified kidney donors, there is a lack of consensus regarding how to optimize the potential of the gifted kidney (and indirectly potentiate the altruistic benefit for the donor). Despite emerging guidance on how to work up unspecified donors, centers have adopted individualized unspecified donor pathways with regards to assessment, evaluation, and use. There are a variety of models for unspecified kidney donation, ranging from donation directly to deceased-donor waiting lists to benefit one recipient or chain transplantations occurring simultaneously (domino-paired donation) or nonsimultaneously (extended altruistic donor chains) to benefit many. After a brief exploration on the basis of altruism, this review will discuss the assessment, evaluation, and reported outcomes associated with unspecified kidney donation. It will also critique current utilization models and highlight some unresolved controversies. The aim is to highlight the principles, practice, and potential of unspecified kidney donation to bridge the current disparate international practice.

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.