Monday, March 7, 2011

Non-simultaneous kidney chains are getting longer

Mike Rees' revolution in non-simultaneous extended altruistic donor (NEAD) chains continues to grow in importance in kidney exchange. Since the 2009 NEJM paper reporting the first NEAD chain, which accomplished 10 transplants (and therefore required 20 surgeries, ten of them nephrectomies), chains have been getting both more frequent and often longer.

The venerable transplant center at the University of Pittsburgh reports its recent involvement in a long chain:
A UPMC First: Transplant Team Participates In Large Multi-State Kidney Chain Involving 32 Operations and 16 Transplants
"The paired kidney exchange, coordinated by the National Kidney Registry, involved 32 patients and 16 transplants performed at 12 U.S. hospitals over two months. It marked the first time that UPMC participated in a kidney chain."

The National Kidney Registry is one of the relatively nimble networks that, following the New England Program for Kidney Exchange, and Rees' Alliance for Paired Donation, have grown by recruiting sometimes overlapping networks of transplant centers.
Sean Hamill at the Pittsburgh Post Gazette gives the story a competitive angle by contrasting the NKR with the national exchange that is slowly gearing up (emphasis added, on which I'll comment after):

"This most recent chain started Dec. 17, 2010, and by the time it ended Feb. 11 it involved 16 donors and 16 recipients at 12 transplant centers in nine states from New York to California. Mr. Johnson's transplant and Ms. Dolezal's kidney removal both took place Feb. 10 in Pittsburgh and both of them are doing well.
"A national program that could push the number of paired donations from nearly 400 last year nationally to 3,000 or more a year has been the dream for the last half decade. That's significant when 93,000 people are on the national waiting list for kidneys and only about 17,000 a year get transplants

"Last fall, the United Network for Organ Sharing, an organization that oversees the nation's organ and transplant network, finally began its long-awaited pilot program that will attempt to do just that and link all of the eligible patients from the nation's more than 200 transplant centers.

"But Garet Hil, founder and president of the National Kidney Registry in Babylon, N.Y., which organized the 32-person chain, said UNOS's pilot program "is a failure."

"Mr. Hil, who runs a consulting and software development company, sits on the Kidney Paired Donation Pilot working group that has been trying to make the program work.

"I've witnessed a program with a flawed design, working in a bureaucratic way that's not going to get many people transplanted," he said Friday in a phone interview. "The program has been out since October and it's only done two transplants and we've done 60 since then -- including this chain" of which UPMC was a part.
"He has a host of criticisms with the pilot program, including that it allows only small chains that would give just two or three people new kidneys at a time, while the National Kidney Registry runs chains, like this recent one, where dozens of people get new kidneys.

"Ken Andreoni, an Ohio State University transplant surgeon who chairs UNOS's kidney committee, has heard Mr. Hil's arguments and concerns before and he believes he's just being too impatient.

"I'm in this for the 50-year- and 100-year-long issues," he said, adding that they will take time to solve.

"He concedes the pilot program is slowed by the bureaucracy of having to follow rigid rules that aim to maximize successful transplants and minimize risk.

"But that's the price you pay when you're creating what is to be a real national program that answers to everyone, unlike Mr. Hil's registry.

"The pilot program has had a difficult time because, first, the patients who have signed on are typically the most difficult patients to match, with significant variables that make them hard to match.

"And while UNOS would love to run long chains like the registry, currently it believes that shorter, two- and three-person-paired chains are safer because they're less complicated, Dr. Andreoni said.

"He doesn't see it as the competition Mr. Hil does.

"In the end, if you get people off the waiting list, that's great," Dr. Andreoni said, "no matter who is doing it."

About the controversy about long versus short chains, the concerns about long chains are based in part on a modeling error, see this earlier post: Nonsimultaneous kidney exchange chains produce more transplants than simultaneous chains

And the issue about having only hard-to-match patients enrolled so far in the national exchange, that is likely to be a problem that will need to be addressed at a fairly fundamental level, because the current incentives make that a tempting strategy for transplant centers. See this earlier post: Kidney exchange when hospitals are the players

Finally, regarding time horizons, I sure hope that in 50 and 100 years we'll have better cures for kidney disease than transplantation. But for the next 10 or 20 it's likely to be the best solution by far for patients with end stage renal disease, and so we'd better keep figuring out how to make the best use of it.

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