In 2001, region 1 of United Network for Organ Sharing (UNOS) developed a program that permitted exchanges between two living donor/recipient pairs (living paired exchanges) and exchanges between a living donor and a deceased donor (list paired exchanges). Delmonico and colleagues report on their results through 2003 including four living paired exchanges and 17 list-paired exchanges (1Delmonico FL Morrissey PE Lipkowitz GS et al.Donor Kidney Exchanges.Am J Transplant. 2004; 4: 1628-1634Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar). The development of a regional consortium is commendable as it requires coordination between competing institutions. The authors deserve additional credit for openly discussing three programmatic snags that their program experienced in its first 2 years. The first was the number of candidates with high priority waiting for a cadaveric kidney. The consortium decided to permit only two high priority candidates at a time “to avoid an unpredictable period of waiting on the list”. While this policy may frustrate those who are waiting for a transplant and have a willing but ABO-incompatible donor, it is not unjust. Justice requires that equals be treated equally; it does not require that potential exchanges trump all other morally relevant allocation considerations. The second obstacle was the need to develop a policy to address the list-paired-exchange recipient whose cadaveric kidney fails in the first month post-transplant. The program did not have a policy initially, and in their first 17 list-paired exchanges, two recipients required a repeat transplant because the initial graft failed within days. Both recipients were given priority for a second deceased donor kidney. On reflection, the consortium decided that future exchange recipients would only receive one kidney with this special allocation priority. Morally we believe this is a more just policy as other recipients do not go to the head of the queue if their graft fails. Whether the paired recipients will be permitted to find another living donor for a second list-paired exchange to regain special priority, however, was not addressed. The consortium's current policy states that list paired exchange is only permissible if the recipient is a candidate for a first deceased donor kidney (1Delmonico FL Morrissey PE Lipkowitz GS et al.Donor Kidney Exchanges.Am J Transplant. 2004; 4: 1628-1634Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar), (although exceptions were made when the list-paired-exchange kidneys failed and they received a second deceased donor kidney). If the recipient can only participate in one list-paired exchange, this needs to be stated explicitly in the consent process. But ethically it is not clear why an individual should not be permitted to arrange for a second list-paired exchange and receive a second deceased donor kidney (or why an individual who has rejected a deceased donor graft should not be permitted to arrange for a first list-paired exchange and obtain a second-deceased donor kidney). The list-paired recipient is not decreasing the available supply to the waitlist, but is providing a better organ in its place. The only ethical reason to prohibit second-deceased donor kidneys to list-paired exchange recipients is the concern that it does greater harm to a subset of those on the waitlist. The third and most serious challenge, then, is the inequities incurred by candidates with blood type O who are worst-off (i.e., have the longest waiting times) and are made even worse-off (i.e., an increased waiting time) by the list-paired-exchange program. We predicted that this would occur (2Zenios S Woodle ES Ross LF Primum Non Nocere: avoiding harm to vulnerable candidates in an indirect kidney exchange.Transplantation. 2001; 72: 648-654Crossref PubMed Scopus (76) Google Scholar). We argued that list-paired exchanges (referred to as indirect exchanges) that involved an ABO-compatible crossmatch positive donor-recipient pair were ethically permissible because the waiting time for individuals within the particular blood group was shortened (3Ross LF Woodle ES Kidney Paired Exchange Programs: an expanded view of the ethical issues.in: Touraine JL Traeger J Betuel H Dubernard JM Revillard JP Dupuy C Organ Allocation: Proceedings of the 30th International Conference on Transplantation and Clinical Immunology. Kluwer Academic Publishers, Dordrecht1998: 285-295Crossref Google Scholar). However, the more likely exchange involves an ABO-incompatible donor-recipient pair such that the person who receives the living donor's kidney is from a different blood-group, than the individual who would have received the deceased donor kidney now to be transplanted into the paired recipient (3Ross LF Woodle ES Kidney Paired Exchange Programs: an expanded view of the ethical issues.in: Touraine JL Traeger J Betuel H Dubernard JM Revillard JP Dupuy C Organ Allocation: Proceedings of the 30th International Conference on Transplantation and Clinical Immunology. Kluwer Academic Publishers, Dordrecht1998: 285-295Crossref Google Scholar). This is because the most likely living donor who cannot donate directly will be an A or B donor who cannot donate to the potential O recipient. Although the number and quality of kidneys available for individuals on the waitlist could be increased by ABO-incompatible list-paired exchanges, and overall waiting time decreased, the exchange is unjust. Justice as fairness only permits policy changes that benefit those who are worst off (i.e, O waitlist candidates who already have the longest waiting time) (4Rawls J A Theory of Justice. Press of Harvard University Press, Cambridge, MA1971Crossref Google Scholar). The data from Delmonico et al. confirm our fears. They claim that the harm is temporary: “the small initial disadvantage to the O-list disappears completely once an exchange program in any given area has been in place for a period equaling the wait-time threshold for unsensitized O-patients in that area” (1Delmonico FL Morrissey PE Lipkowitz GS et al.Donor Kidney Exchanges.Am J Transplant. 2004; 4: 1628-1634Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar). We disagree. If the pool of transplant candidates is divided into two groups, one group with higher priority and another group with lower (or standard) priority, then the average waiting time for the patients in the standard group will be higher than their average waiting time, in a system where no patients enjoy higher priority. This effect is not transient, it persists over time, and can only be mitigated if the supply of organs in the system with priorities is sufficiently higher than in the second system with no priorities (which it will never be). Furthermore, the long-term harm will only get worse as the standard waitlist grows at a faster rate than the supply of kidneys (both living and deceased donor). The current list paired exchange process harms the worst-off group and is therefore unjust (3Ross LF Woodle ES Kidney Paired Exchange Programs: an expanded view of the ethical issues.in: Touraine JL Traeger J Betuel H Dubernard JM Revillard JP Dupuy C Organ Allocation: Proceedings of the 30th International Conference on Transplantation and Clinical Immunology. Kluwer Academic Publishers, Dordrecht1998: 285-295Crossref Google Scholar, 4Rawls J A Theory of Justice. Press of Harvard University Press, Cambridge, MA1971Crossref Google Scholar). ABO-incompatible list paired exchanges with O-paired recipients should not be performed (5Ross LF Zenios S Restricting living donor/cadaver donor exchanges to ensure that standard blood type O waitlist candidates benefit.in: Transplantation. 2004Google Scholar).
