Motivations and outcomes of compatible living donor-recipient pairs in paired exchange.

Increasing numbers of compatible pairs are choosing to enter paired exchange programs, but motivations, outcomes, and system-level effects of participation are not well described. Using a linkage of the Scientific Registry of Transplant Recipients and National Kidney Registry, we compared outcomes of traditional (originally incompatible) recipients to originally compatible recipients using the Kaplan-Meier method. We identified 154 compatible pairs. Most pairs sought to improve HLA matching. Compared to the original donor, actual donors were younger (39 vs. 50 years, p < .001), less often female (52% vs. 68%, p < .01), higher BMI (27 vs. 25 kg/m², p = .03), less frequently blood type O (36% vs. 80%, p < .001), and had higher eGFR (99 vs. 94 ml/min/1.73 m², p = .02), with a better LKDPI (median 7 vs. 22, p < .001). We observed no differences in graft failure or mortality. Compatible pairs made 280 additional transplants possible, many in highly sensitized recipients with long wait times. Compatible pair recipients derived several benefits from paired exchange, including better donor quality. Living donor pairs should receive counseling regarding all options available, including kidney paired donation. As more compatible pairs choose to enter exchange programs, consideration should be given to optimizing compatible pair and hard-to-transplant recipient outcomes.

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

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

The 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.

HLA Matching Trumps Donor Age: Donor-Recipient Pairing Characteristics That Impact Long-Term Success in Living Donor Kidney Transplantation in the Era of Paired Kidney Exchange.

BACKGROUND: We sought to identify donor characteristics influencing long-term graft survival, expressed by a novel measure, kidney life years (KLYs), in living donor kidney transplantation (LDKT). METHODS: Cox and multiple regression analyses were applied to data from the Scientific Registry for Transplant Research from 1987 to 2015. Dependent variable was KLYs. RESULTS: Living donor kidney transplantation (129 273) were performed from 1987 to 2013 in the United States. To allow sufficient time to assess long-term results, outcomes of LDKTs between 1987 and 2001 were analyzed. After excluding cases where a patient died with a functioning graft (8301) or those missing HLA data (9), 40 371 cases were analyzed. Of 18 independent variables, the focus became the 4 variables that were the most statistically and clinically significant in that they are potentially modifiable in donor selection (P <0.0001; ie, HLA match points, donor sex, donor biological sibling and donor age). HLA match points had the strongest relationship with KLYs, was associated with the greatest tendency toward graft longevity on Cox regression, and had the largest increase in KLYs (2.0 year increase per 50 antigen Match Points) based on multiple regression. CONCLUSIONS: In cases when a patient has multiple potential donors, such as through paired exchange, graft life might be extended when a donor with favorable matching characteristics is selected.

Kidney transplant chains amplify benefit of nondirected donors.

IMPORTANCE: Despite the potential for altruistic nondirected donors (NDDs) to trigger multiple transplants through nonsimultaneous transplant chains, concerns exist that these chains siphon NDDs from the deceased donor wait list and that donors within chains might not donate after their partner receives a transplant. OBJECTIVE: To determine the number of transplantations NDDs trigger through chains. DESIGN: Retrospective review of large, multicenter living donor-recipient database. SETTING: Fifty-seven US transplant centers contributing donor-recipient pairs to the database. PARTICIPANTS: The NDDs initiating chain transplantation. MAIN OUTCOMES MEASURE: Number of transplants per NDD. RESULTS: Seventy-seven NDDs enabled 373 transplantations during 46 months starting February 2008. Mean chain length initiated by NDDs was 4.8 transplants (median, 3; range, 1-30). The 40 blood type O NDDs triggered a mean chain length of 6.0 (median, 4; range, 2-30). During the interval, 66 of 77 chains were closed to the wait list, 4 of 77 were ongoing, and 7 of 77 were broken because bridge donors became unavailable. No chains were broken in the last 15 months, and every recipient whose incompatible donor donated received a kidney. One hundred thirty-three blood type O recipients were transplanted. CONCLUSION AND RELEVANCE: This large series demonstrates that NDDs trigger almost 5 transplants on average, more if the NDD is blood type O. There were more blood type O recipients than blood type O NDDs participating. The benefits of transplanting 373 patients and enabling others without living donors to advance outweigh the risk of broken chains that is decreasing with experience. Even 66 patients on the wait list without living donors underwent transplantation with living-donor grafts at the end of these chains.

The National Kidney Registry: 175 transplants in one year.

Since organizing its first swap in 2008, the National Kidney Registry had facilitated 389 kidney transplants by the end of 2011 across 45 U.S. transplant centers. Rapid innovations, advanced computer technologies, and an evolving understanding of the processes at participating transplant centers and histocompatibility laboratories are among the factors driving the success of the NKR. Virtual cross match accuracy has improved from 43% to 94% as a result of improvements in the HLA typing process for donor antigens and enhanced mechanisms to list unacceptable HLA antigens for sensitized patients. By the end of 2011, the NKR had transplanted 66% of the patients enrolled since 2008. The 2011 wait time (from enrollment to transplant) for the 175 patients transplanted that year averaged 5 months.

National Kidney Registry: 213 transplants in three years.

Since its establishment in 2008, the National Kidney Registry has facilitated 213 kidney transplants between unrelated living donors and recipients at 28 transplant centers. Rapid innovations in matching strategies, advanced computer technologies, good communication and an evolving understanding of the processes at participating transplant centers and histocompatibility laboratories are among the factors driving the success of the NKR. Virtual cross match accuracy has improved from 43% to 91% as a result of changes to the HLA typing requirements for potential donors and improved mechanisms to list unacceptable HLA antigens for sensitized patients. A uniform financial agreement among participating centers eliminated a major roadblock to facilitate unbalanced donor kidney exchanges among centers. The NKR transplanted 64% of the patients registered since 2008 and the average waiting time for those transplanted in 2010 was 11 months.

The National Kidney Registry: transplant chains--beyond paired kidney donation.

The National Kidney Registry (NKR) has facilitated more than 100 transplants at 24 centers in the past 2 years and the numbers are rapidly increasing. The NKR has inherent capability for rapid change as innovations are developed and incorporated in the approach to matching donors and recipients in transplant chains. Kidneys are shipped with geotracking devices utilizing existing OPO procedures whenever patients are willing to accept them. This reduces the need for donor travel and increases the geographic area where matches can be made. Out-of-sequence transplants can be performed to improve logistics. Matching software is designed to facilitate chain transplantation and incorporates metrics that help transplant centers develop strategies to improve the chances that their patients can be transplanted. Daily match runs and close attention to repairing broken chains have been critical to growing the number of transplants that can be facilitated. A number of new innovations are expected to increase the opportunities for patients and their potential living donors.