The carefully designed protocol and consideration of its ethical consequences are offered for public comment in the June 12 issue of the New England Journal of Medicine.
"We wanted to devise an ethical framework for a fair and voluntary exchange in order to make the best use of a scarce resource," says ethicist Lainie Friedman Ross, M.D., Ph.D., assistant professor of pediatrics and associate director of the MacLean Center for Clinical Medical Ethics at the University of Chicago Medical Center and first author of the study. "At the same time, we wanted to minimize the risk of coercing donors and to ensure that this exchange does not promote the commercialization of organ donation.
"We think the proposed protocol meets these criteria," adds Ross, "but by seeking public and professional criticism of the proposal before performing the procedure -- an approach to the ethics of innovation previously developed at the University of Chicago -- we hope to refine the process and gauge public acceptance of this imaginative project."
To make it easier for the general public to comment, the authors have created an
open web site for responses, suggestions or critiques at
In 10 to 20 percent of cases at the University of Chicago Hospitals, patients who need a kidney transplant have family or friends who agree to donate, but the willing donor is found to be biologically unsuited for that specific recipient. In the past, this meant a recipient had to wait in line for years, dependent on dialysis, until a kidney from a cadaver donor became available.
In December, 1996, 34,550 people in the United States were on the United Network for Organ Sharing (UNOS) waiting list for a kidney. Last year 1,814 died waiting.
Success rates with living kidney donors (around 70% graft survival five years after surgery) exceed those using cadaveric donors (58%). Until recently, living-donor kidney transplantation was confined to genetically similar relatives. Now, improved immunosuppression allows increased use of biologically dissimilar but emotionally related kidney donors, such as a spouse. Graft survival five years after surgery from unrelated living donors is about the same as from related but non-identical donors.
Despite improved medications, however, some donor-recipient pairs remain incompatible because of discordant blood types or antagonistic immune systems.
In this proposal, an incompatible donor could still contribute a kidney, but it would go instead to an unrelated second recipient. In exchange, the volunteer donor for the second recipient would contribute a kidney for transplantation to the first recipient. By exchanging donor kidneys, both recipients receive a timely transplant with a living, compatible kidney, circumventing the incompatibility with their own living donor.
Although medically feasible, a donor exchange creates unusual logistical and ethical challenges. For example, each set of transplants will require coordination of the evaluation and scheduling of four patients: two donors and two recipients. The surgical procedures will require the simultaneous efforts of four transplant teams in four operating rooms.
But the tactical concerns are dwarfed by the ethical challenges of ensuring informed consent and confidentiality for all four patients. In this pilot study, recipients and donors will be asked whether they would consider participation in this research protocol before any work-up as a direct donor has begun. Only if a recipient has no emotionally related match and a potentially willing exchange donor will the transplant team re-address the option of an exchange with the donor and recipient.
"Of utmost importance in this protocol is the protection of voluntary organ donors," explains E. Steve Woodle, M.D., senior author of the proposal and director of renal transplantation at the University of Chicago.
The physicians were concerned that the organ exchange might compromise the voluntary nature of kidney donation. To make certain that the donor's decision was voluntary, the researchers added a psychiatric evaluation to the protocol, providing one more opportunity to withdraw consent.
In order to ensure that one donor does not withdraw after the other has already entered surgery, both transplants will be performed simultaneously.
The authors predict that the kidney-exchange protocol will be "as ethically acceptable to donors and recipients as direct donation," and that success rates will equal those of direct donation to a spouse or friend.
If that is the case, however, they recommend that such protocols be restricted to major transplant centers, which have the capability to perform simultaneous transplants and the resources to ensure that patients give voluntary and informed consent. A nationwide registry may offer less protection to donors and complicate the timing of an organ exchange.
Additional authors include David Rubin, M.D., department of medicine; Mark Siegler, M.D., MacLean Center for Clinical Medical Ethics; nephrologist Michelle Josephson, M.D.; and Richard Thistlethwaite, M.D., Ph.D., section chief of transplantation, all from the University of Chicago. Web site prepared by Rubin and David Liebovitz, M.D.