Living Kidney Donation Chains May Help More Get Transplants

These networks begin with one altruistic living donor, study explains

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By Serena Gordon
HealthDay Reporter

WEDNESDAY, March 11 (HealthDay News) -- In 2006, one healthy young man stepped forward, willing to give one of his kidneys to a complete stranger. Two years later, 10 people had received new kidneys from that one remarkable altruistic act.

That's because his donation started the first nonsimultaneous, extended altruistic-donor (NEAD) chain. The woman who received the altruistic donor's kidney had a family member (her husband) who was willing to donate, but couldn't donate to his wife. So, he gave his kidney to a young woman whose mother was also willing to donate, but didn't match, and so on, and so on, until 10 successful transplants had occurred. The final donor in the chain is still waiting for a good match to someone in need of a kidney.

If all of this sounds complex and difficult to coordinate, it is. But, fortunately the doctors involved now have sophisticated computer programs to help them match possible recipients to willing donors.

"We've now transplanted 19 people through NEAD chains," said study author Dr. Michael A. Rees, director of renal transplantation at the University of Toledo Medical Center. "We've started six NEAD chains. The first one is 10 in length, the second is five," he said, adding that he hopes each chain never ends.

Details of the first NEAD chain are published in the March 12 issue of the New England Journal of Medicine.

Nearly 80,000 people are waiting on the transplant list for a new kidney, according to the Organ Procurement and Transplantation Network. Many of these people have a friend or family member who is willing to donate a kidney but can't because of a mismatch or other problem.

People can find themselves unable to donate to a loved one if their blood type doesn't match or if they've developed certain antibodies, which can occur through blood transfusions or in pregnancy.

But instead of turning those willing donors away, doctors came up with the idea of paired donation. In paired donation, two transplant recipients essentially swap their donors to make a good donor-recipient match. These operations are done at the same time, requiring four operating rooms, to assure that no one backs out once their loved one has received a new kidney.

While paired donation was gaining a foothold in transplant medicine, Rees heard about an idea he thought might work. The idea was to come up with an exchange list for people who had willing, but incompatible donors. He found 10 pairs in his own center and sat down with all of their information at his kitchen table. He said he quickly realized that "a computer needs to do this complex matching, not me."

Rees' father actually designed the first computer model, which has since gone through major changes. M. Utku Unver, a theoretical economist from Boston College, led the team that redesigned the computer matching system that assigns point values to different characteristics that donors and recipients share. The higher the number, the better the match.

Donation chains allow for more people to receive transplants and once a match has been made, it's easier than trying to coordinate four simultaneous surgeries, according to Rees.

From the first donor chain, 10 transplants have been done in four states, including three that were done simultaneously at Johns Hopkins. None of the donors in the chain have reneged on their promise to donate an organ.

Living donations don't always go to the sickest person, as deceased organs do, according to Dr. Kenneth Andreoni, chairman of the subcommittee for national kidney paired donations at UNOS, the agency that directs the allocation of donated organs. But he said that NEAD chains can help reduce the time people spend on a waiting list, simply by reducing the list's size.

"The more you can get transplanted, the more access people on the list have to deceased donors. It's really a win-win situation," Andreoni said. But he added that because of the complexity of managing NEAD chains, it would be better to have a national list of recipient-donor pairs, so that as many pairs as possible can be matched up -- without having to create a chain.