A groundbreaking approach to increasing the quantity and quality of kidney transplants across the country was explained by a UT Medical Center physician in the March 12 edition of the New England Journal of Medicine. The article titled “A Nonsimultaneous, Extended, Altruistic Donor Chain” highlights the world’s longest chain of kidney transplants made possible by maximizing the good that can come from an altruistic, or Good Samaritan, kidney donor.
Lead author of the report, Dr. Michael A. Rees, UT professor of urology, director of renal transplantation at UT Medical Center and medical director of the Alliance for Paired Donation (APD), said, “By passing the altruism of the first donor in the chain on to all subsequent donors, incompatible pairs no longer have to pay back the gift given to them. Instead, the barriers between donors and recipients are overcome through a chain of nonsimultaneous transplants in which participants ‘pay it forward’ to others in need.”
Typical paired donations occur when someone who needs a kidney has a loved one who is willing to donate one, but their body chemistry is not a good match. That willing donor and recipient are then placed in a computer registry until they can be matched with a pair in the same situation. Simultaneous kidney transplants then occur, so that neither party can harm the other by backing out of the arrangement.
The New England Journal of Medicine report details a twist on the paired donation — the first ever “non-simultaneous, extended, altruistic-donor” (NEAD) transplant chain in which willing donors make their donation only after their recipient has already received a transplant.
“When an altruistic donor starts a kidney donation chain, it is no longer imperative that the transplants are done simultaneously,” Rees said. “If a donor along the chain fails to donate to the next recipient, the outcome will be unfair, but the waiting pair will not have been irreparably harmed and can still enter into a new paired donation or chain because the pair is still intact.”
The authors suggest that this approach may help increase the number of transplants performed. Simulations show that paired donations involving more than two pairs will yield substantially more transplants than conventional two-way exchanges, and NEAD chains can overcome insurmountable logistical barriers, such as having 20 available operating rooms to perform 10 simultaneous transplants.
Those claims are supported in the New England Journal of Medicine case report of 10 kidney transplants initiated in July 2007 by a single altruistic donor and coordinated over eight months by two large paired-donation registries. The transplants involved six hospitals in five states, and no one reneged on his or her commitment.
The transplants occurred at UT Medical Center, Banner Good Samaritan Hospital in Phoenix, Ohio State University Medical Center, Johns Hopkins Hospital and Wake Forest Baptist Medical Center, and were made possible by an altruistic donor who came through Buffalo General Hospital.
Several other individuals played critical roles in making this NEAD chain possible through the development of computer models and software that identify the best possible matches. Jonathan Kopke of the Department of Public Health Sciences at the University of Cincinnati created the Web version of the Alliance for Paired Donation software; Dr. Alvin Roth, professor of economics at Harvard University, helped write the “matching” algorithm used by the APD; and Tuomas Sandholm of the Computer Science Department at Carnegie Mellon University and Utku Unver of the Department of Economics at Boston College developed the process for optimizing match runs.
In addition to helping potential recipients in incompatible pairs obtain transplants, the article states NEAD chains may make it possible for them to receive higher-quality transplants. Introduction of an altruistic donor allows greater flexibility for every donor to be matched to the recipient for whom the donor provides maximum benefit. Also, kidneys from living donors last longer on average than those from deceased donors —16.5 years versus 8.5 years.
Rees added that the potential for helping many patients instead of just one can serve as a strong motivation for potential altruistic donors. While in 2006 there were only 68 altruistically donated kidney transplants performed in the United States, more than 250 potential altruistic donors have registered with the Alliance for Paired Donation.
Read the article in the New England Journal of Medicine here.
For more information, go to the Alliance for Paired Donation Web site at http://paireddonation.org.