Paired Kidney Exchange: Changing the Future of Organ Transplants

  • Kai Fong was about to save the lives of 11 people without knowing it. A college tennis coach from Idaho, Fong underwent testing to see if he was a kidney donor match for a co-worker. When the match was incompatible, Fong decided to donate anyway—this time to a complete stranger. He entered a paired kidney exchange program—essentially databases filled with names of people in need of kidney transplants and people willing to donate.


    Doctors found a match half way across the country: Georgia resident Phyllis Anderson. She had been on the transplant waiting list for five years with end-stage renal disease from diabetes and pneumonia complications. Fong flew to Piedmont Atlanta Hospital, where Anderson successfully received her new organ. Soon after, her husband donated his kidney to someone else.

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    Phyllis Anderson with her organ donor, Kai Fong.

    Image courtesy of Piedmont Hospital.


    This one act of generosity triggered a chain reaction of paired donations across several states—from Texas to Michigan to New Jersey—that ultimately ended with 11 people receiving new kidneys.


    This phenomenon is known as Non-simultaneous Extended Altruistic Donor (NEAD) Chains. And it’s a part of the growing paired kidney exchange system.


    What is paired kidney exchange donation?

    According to the Living Kidney Donors Network, roughly one-third of people who wish to donate are not a match for their planned recipient. This is when kidney exchanges come in. Paired donation occurs when incompatible pairs find their matches from a pool of donors and recipients, and they “swap” or “exchange” kidneys. For example, say you want to donate your kidney to your mother, but you’re not a match. You can then enter your name into a kidney exchange database and a recipient will be found for you. In return, your mother will be matched up with someone else in the database who is in the same situation. The illustration below is a visual representation of a how a paired kidney exchange works.


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    The Kidney Paired Donation Pilot Program is a national database still in development. Most programs are currently regional, such as the Alliance for Paired Donation that participates with Piedmont, or the New York-based nonprofit National Kidney Registry. This technique is the fastest growing source of transplantable kidneys in the last 10 years, explains Dr. Miguel Tan. Tan is the surgical director of kidney and pancreas transplantation at Piedmont Transplant Institute in Atlanta.  Piedmont performs around 150 to 170 kidney transplants annually.


    There are two types of paired kidney exchanges:


    One pair of people donates to another pair of people and vice versa, as seen in the illustration above. These transplant surgeries usually occur simultaneously, with multiple operating rooms running at once—even from states away. Transplant teams from different transplant hospital centers time it so both donors donate at the same time and both recipients receive them afterward. The reason for this timing, explains Tan, is so no one is at a disadvantage. For example, if someone becomes sick or backs out and is left without a donor to act as leverage for the swap system.


    Altruistic/NEAD chain

    Altruistic donors, like Kai Fong, donate to a recipient-donor pair who then “pays it forward” by donating a kidney to another pair, and so forth down the line. “The big advantage to having a domino chain is you can get more people transplants and it doesn’t have to be done at a certain time; it just has to be done in a certain order,” says Tan. Piedmont participated in the first transcontinental exchange where patients came from Greece, Caribbean and U.S. The longest chain ever performed involved 30 pairs in 2011.


    How does a kidney hop between states? After being inspected for damage or disease, the kidney is packed on ice and sent as cargo on a high-priority medical emergency flight to minimize wait time. The kidney is accompanied by a courier from the transplant hospital on long flights. Doctors have 24 hours to package, ship, and implant a kidney once it’s removed.

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    Living vs. deceased donors

    “A living donor kidney, on average, lasts twice as long as a deceased donor kidney,” explains Tan. This is particularly important for young people who need their new kidney to last a long time. Rejection rates and the amount of immunosuppressant drugs needed are also lower with a living donor kidney compared to a deceased donor kidney. Not to mention living donor kidneys have a much higher chance of working within 24 hours after the surgery. Up to 30 percent of deceased donor kidneys can take anywhere from a few days to a few weeks to kick in, says Tan.


    See the infographic below on how life expectancy for patients differs among dialysis, deceased, and living donations.




    As most know by now, people only need one kidney to be healthy. Once the additional kidney is removed, the remaining kidney realizes it’s solo and grows a little bit larger to cover the work of two.   “Having two kidneys is a redundant system, actually, because if you have two kidneys you are working at 100 percent function. If you donate a kidney, you drop down to 60 percent function, which is ok because you only need 30 percent function to be normal,” explains Tan. What this means is a donor will have normal kidney function, but they won’t have much reserve in the future if something happens, like if they develop diabetes. Donors are tested and evaluated beforehand to ensure they have a healthy medical history and will most likely not experience future problems.


    Donating a kidney does not increase a person’s chances of developing kidney disease. However, as with any major surgery, there are potential risks. Post-operative complications are generally short term and treatable and include infection, bleeding, and fever. The risk of death is .03 percent. Tan says thanks to technology these surgeries are now mostly laparoscopic and minimally invasive. The operation itself takes around two to three hours. At Piedmont, Tan says three-quarters of donors go home within 24 hours. Advancements like these make it easier for more living donors to volunteer, a crucial step forward as deceased donation has stalled.


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    Tan says the number of deceased kidney donors peaked around 2006. But the need for kidney transplants continues to grow by 1 or 2 percent each year, forcing thousands of people to face a grim reality.  Approximately 100,000 people in the U.S. are currently waiting for a kidney, but doctors perform only about 15,000 transplants a year. Roughly 5,000 people die each year waiting for a kidney transplant.


    Here’s a visualization of those numbers:  





    “The  big urgency is that people are dying on the list,” says Tan. “But now with living donation, and especially with paired exchange, we have a lot more options for getting people transplants.” He also says altruistic donors can potentially double the amount of transplants performed.


    The paired exchange program isn’t a guarantee. Donors will always be matched, but some recipients who are highly sensitized with lots of antibodies may not find a match.  Still, for people like Phyllis Anderson, it’s a miraculous gift. After receiving her kidney from Fong, she lived to celebrate her 40th wedding anniversary with a trip to Los Cabos, Mexico, and hopes to celebrate many more.


    For more information on becoming a living organ donor and paired kidney exchanges, visit


Published On: May 09, 2014