The practice of transplantation is unique in medicine because it is governed by a defining federal statute—the National Organ Transplantation Act (NOTA) of 19841 and amendments made to it in 1988 with the Health Omnibus Extension. NOTA has provided guidance to the transplant community for 25 years since it was made operational,2 helping the community navigate the challenges of improving equity in an environment of rapid clinical and technological advances. However, the time has arrived when advances in clinical practice cause the transplant community to consider whether NOTA needs updating to keep pace with a rapidly evolving field. The rules of NOTA pertaining to organ allocation were not written to anticipate the recovery of organs with a large range of quality and their distribution over long geographical distances. The wider sharing of organs without accounting for their ability to tolerate the increase in cold ischemic time that is inherent to this allocation is a likely contributor to the increasing number of discarded kidneys.3

Organ discard is an animating topic in the field of kidney transplantation. Despite efforts to improve the utilization of marginal organs,4 the discard rate of kidneys with Kidney Donor Profile Index (KDPI) >0.85 remains stubbornly higher than 50% (Scientific Registry of Transplant Recipients data). The reasons for organ discard are numerous and include a lack of patient readiness for transplantation, allocation system inefficiency leading to longer cold ischemic times, and transplant center resource constraints. However, a factor that is hard to quantify but well known to those with clinical experience is the concern on the part of surgeons and physicians who make the decision to accept an organ that they are doing right by their patient when accepting a specific kidney for transplantation. As the quality of the organ, as assessed by increasing KDPI, declines, this concern rises. The report published in this issue of CJASN by Kadatz et al.5 provides supporting evidence to those accepting doctors trying to appropriately match donor organs with recipients that there are patients who will meaningfully benefit from these higher-KDPI kidneys. The patients who will benefit the most are those not yet on dialysis.

By conducting a thorough study that includes a mate kidney comparison and multiple sensitivity analyses, Kadatz and colleagues demonstrate that not only do preemptively transplanted high-KDPI kidneys outperform like comparisons, but they also outperform lower KDPI kidneys that are transplanted into patients on dialysis. In these comparisons, high-KDPI kidneys provided longer death-censored graft survival and overall patient survival. The authors correctly point out that a potential limitation of this study is lead time bias because the improved outcomes may be due to more native eGFR or fewer comorbidities in the recipients. In addition, this study does not compare outcomes of preemptive transplantation with high-KDPI kidneys with waiting for a lower KDPI kidney; therefore, this approach at present only has data to support use in patients who are not expected to receive traditional offers. These critiques aside, because a long-standing goal of the transplant system is to make use of kidneys at risk of discard,4 this study provides important clinical guidance on how to best use high-KDPI kidneys and raises provocative questions about how to better construct allocation policy.

These data force policy makers and the transplant community to consider whether the policies currently being developed enable the transplant system to serve the individual needs of its patients appropriately. Although the literature on the benefit of transplantation with high-KDPI kidneys in aggregate supports the use of high-KDPI organs for adding more life years to the population at large,6 it does not provide guidance about which individual patient is best served by them. This knowledge resides with experienced transplant professionals who match these organs to patients best suited to receive them. In addition, the aggregate data do not account for differences in transplant center expertise and their available resources, which enable the transplanting of more complex patients with high-KDPI kidneys. This creates a discordance between what the data suggest should occur and observed individual patient outcomes.

A major contributor to this difference between predicted and observed outcomes is the stipulation within NOTA that organs are allocated to individual patients sequentially and not preferentially to those best suited for them. At the time of its writing, this approach was appropriate because there were fewer transplant centers spread farther apart geographically. Sequential allocation to patients ensured an opportunity to receive an organ offer, regardless of where they lived. While the issue of organ discard is complicated and multifaceted, as the transplant community has implemented policies to increase the sharing of organs over larger geographic areas, there has been an association between longer cold ischemic time and organ discard.3 The need to make offers sequentially to individual patients imposes delays in organ placement that lead to increased cold ischemia times in donated organs. In the case of high-KDPI kidneys, these are the organs least able to tolerate prolonged cold ischemic time,7 and the delay leads to a cascade of offer declines that results in organ wastage.

There have been attempts at both the national and local levels to improve the utilization of kidneys with higher KDPI. The Collaborative Innovation and Improvement Network Project sponsored by the Organ Procurement and Transplantation Network attempted to integrate best practices between transplant centers to improve utilization.4 This had only modest success. Individual transplant center approaches have many different names: brevity matching, dealing from the bottom of the deck, and accelerated placement. Although the names are different, the goal is the same: to rapidly pair an organ at risk of discard with a patient who will benefit from it. However, both national and local approaches attempting to reduce organ discard are hampered by the mandate of NOTA to allocate an organ to a patient and not a center.

To meaningfully decrease organ discards, the allocation policy needs to facilitate rapid placement of organs at risk of discard to transplant centers that have the expertise to use them. Approaches to accomplish this do not require completely abandoning the principle of allocating organs to individual patients. Thresholds can be identified where the risk of discard increases significantly.8 Crossing a threshold would trigger a new pathway for allocation.9 This pathway could take different forms: batch allocation to the next ten patients on the waitlist with the first responding program receiving the offer for that patient, batch allocation to the next ten programs represented on the waitlist with the first responding program receiving the offer to use in any patient on their list deemed appropriate, and allocation to a program with known expertise in using such organs. However, these and other approaches will all require modification of NOTA to permit allocation to centers and not patients when justifiable criteria are met.

Enacting these proposed changes would require the transplant community to confront issues of inequity. In addition to the obvious issues of differential access to transplant centers willing to use high-KDPI organs, Kadatz et al. found that preemptive utilization of high-KDPI kidneys was associated with inequity. Their analysis found that “preemptive recipients were more likely to be White, female, older, privately insured, and have greater than high school education, but were less likely to have diabetes-related kidney failure.”5 This requires the community to decide where is the balance between treating all similarly situated individuals similarly and promoting system efficiency to achieve maximal utilization of donated organs.10 For this question, there are many valid answers, and not one will win the debate, but the discussion is important. A recent report by the National Academies of Sciences, Engineering, and Medicine concluded that to promote equity in access to kidney transplantation, preemptive placement on the waitlist should be removed from the policy.11 It is true that this would increase equity. However, it is also true that preemptive referral for kidney transplantation is the standard of care for patients with CKD. Moreover, it is without exception that a discarded organ provides equity to no one. Therefore, until the availability of organs meets the need of patients with organ failure, the transplant community may be forced to knowingly tolerate not fully achieving all its equity goals in an effort to maximize the use of donated organs.

Kidney transplantation has evolved since the 1980s from a nascent therapy for kidney failure to the preferred option. Currently, it is offered to patients of much greater age and with medical comorbidities that were once considered contraindications. Coupled with this, the spectrum of donated organs that are recovered for transplantation has broadened to a degree that was unimaginable in the 1980s. Both truths are a testament to the resourcefulness of the transplant community to find new ways to serve patients. Throughout these advances, NOTA has remained constant, and this has benefited the transplant community. The principles of NOTA have guided the community through many contentious issues, and year over year, more transplants are performed. However, the time has been reached when a thoughtful reconsideration of NOTA is required to prepare for the challenges and changes that are in the future for solid organ transplantation.

Disclosures

R.N. Formica Jr. reports consulting relationships with Sanofi Pharmaceuticals and Veloxis Pharmaceuticals, does non-branded educational lectures for Sanofi, and serves as an Associate Editor of CJASN and a member of the Organ Procurement and Transplantation Network Board of Directors.

Funding

None.

Acknowledgments

The content of this article reflects the personal experience and views of the author(s) and should not be considered medical advice or recommendation. The content does not reflect the views or opinions of the American Society of Nephrology (ASN) or CJASN. Responsibility for the information and views expressed herein lies entirely with the author(s).

Because Dr. Richard N. Formica Jr. is an Associate Editor of CJASN, he was not involved in the peer-review process for this manuscript. Another editor oversaw the peer-review and decision-making process for this manuscript.

Author Contributions

Conceptualization: Richard N. Formica Jr.

Writing – original draft: Richard N. Formica Jr.

Writing – review & editing: Richard N. Formica Jr.

References 3. Puttarajappa CM, Hariharan S, Zhang X, et al. Early effect of the circular model of kidney allocation in the United States. J Am Soc Nephrol. 2023;34(1):26–39. doi:10.1681/ASN.2022040471 4. Wey A, Foutz J, Gustafson SK, et al. The Collaborative Innovation and Improvement Network (COIIN): effect on donor yield, waitlist mortality, transplant rates, and offer acceptance. Am J Transplant. 2020;20(4):1076–1086. doi:10.1111/ajt.15657 5. Kadatz MJ, Gill J, Gill J, et al. The benefits of preemptive transplantation using high–Kidney Donor Profile Index kidneys. Clin J Am Soc. 2023;18(5):634–643. doi:10.2215/CJN.0000000000000134 6. Massie AB, Luo X, Chow EK, Alejo JL, Desai NM, Segev DL. Survival benefit of primary deceased donor transplantation with high-KDPI kidneys. Am J Transplant. 2014;14(10):2310–2316. doi:10.1111/ajt.12830 7. Summers DM, Johnson RJ, Hudson A, Collett D, Watson CJ, Bradley JA. Effect of donor age and cold storage time on outcome in recipients of kidneys donated after circulatory death in the UK: a cohort study. Lancet. 2013;381(9868):727–734. doi:10.1016/s0140-6736(12)61685-7 8. Zhou S, Massie AB, Holscher CM, et al. Prospective validation of prediction model for kidney discard. Transplantation. 2019;103(4):764–771. doi:10.1097/tp.0000000000002362 9. Callaghan CJ, Mumford L, Pankhurst L, Baker RJ, Bradley JA, Watson CJE. Early outcomes of the new UK deceased donor kidney fast-track offering scheme. Transplantation. 2017;101(12):2888–2897. doi:10.1097/tp.0000000000001860 10. Formica RN Jr, Schold JD. The unintended consequences of changes to the organ allocation policy. J Am Soc Nephrol. 2023;34(1):14–16. doi:10.1681/ASN.0000000000000009 11. Kizer KW, English RA, Hackmann M, eds. Realizing the Promise of Equity in the Organ Transplantation System. National Academies of Sciences, Engineering, and Medicine; 2022. Accessed February 16, 2023. https://nap.nationalacademies.org/catalog/26364/realizing-the-promise-of-equity-in-the-organ-transplantation-system