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Kidney swapping can increase organ donor pool

Jul 05 2016

On any given day, more than 100,000 people are on the waiting list for a kidney transplant. Most wait in worsening health for an average of seven years before getting a kidney from someone who has died. Not all are so lucky — thousands die while waiting for a transplant.

Fortunately the concept of paired kidney donation, or kidney swaps, is catching on, making more kidneys available and helping patients get transplants earlier, often with better results.

On average, 3,000 people are added to the kidney waiting list each month.

Paired kidney donation involves two or more live donor transplants. If a living kidney donor doesn’t match with the person they wanted to donate to, they can exchange kidneys with another donor/recipient pair in the same situation, if they are a match for that recipient. Sometimes the chain of donations is longer, involving more than two donor/recipient pairs to find the right match for everyone. In total, there have been more than 3,500 paired transplants in the U.S., according to Michael Rees, M.D., Ph.D., head of kidney transplantations at University of Toledo Medical Center in Ohio.

“There is an organ donor shortage. Our primary challenge is how we can increase the pool of available organs for patients waiting on the transplant list,” said James Coates, M.D., M.B.A., clinical head of Aetna’s National Medical Excellence Program®.

On average, 3,000 people are added to the kidney waiting list each month. In 2014, more than 17,000 kidney transplants took place in the U.S. Of those transplants, close to 12,000 came from deceased donors and about 5,500 came from living donors. While waiting for a transplant, almost 5,000 people died and another 3,700 became too sick to receive a new kidney.

At the start of 2016, there were 121,678 people waiting for an organ transplant in the U.S. Of those, about 85 percent were waiting for a kidney, according to the National Kidney Foundation.

The difficulty with finding a matching organ donor

While the organ donor pool is slowly growing, there are a variety of obstacles that may prevent a transplant candidate from receiving an organ. Having the correct blood type between the donor and recipient is important, but antibodies against other humans also play a role in the matching process. Antibodies help identify and remove foreign targets in the body, such as viruses and bacteria.

It’s even more difficult for women who have been pregnant to find a match because their bodies may have created antibodies against their child and child’s father during pregnancy.

“The likelihood of finding an acceptable match for these women is extremely small because there are too many antibodies against humans,” Rees said. “We can’t get a big enough pool for them.”

Databases to help find kidney matches

The idea of paired kidney donations was first raised in the 1980s and first implemented in the United States in 2000. About that time, Rees and his father designed the first internet-based paired kidney donation matching system. Four years later, Rees completed the first transplant using the system. In 2006 he founded the Alliance for Paired Kidney Donation, a non-profit organization helping people receive new kidneys through a paired kidney donation or swap. To date, the Alliance for Paired Kidney Donation has facilitated more than 350 transplants, according to Rees.

Another national database is operated by the United Network for Organ Sharing (UNOS), a private non-profit that operates the Organ Procurement and Transplantation Network. The UNOS database contains information from every person in the U.S. waiting for an organ transplant and provides matches to organs from living donors and deceased donors. Medical information is put into the national database and the organization is estimated to match pairs twice a week, according to its website.

Although the two databases are operated by independent organizations, there could be overlapping information because transplant centers may send information about a candidate to both UNOS and the Alliance for Paired Kidney Donation, according to Coates.

It’s unclear if the overlapping information between systems can be beneficial for the patient because it can be bad for efficiency overall, Rees said.

Living donor vs deceased

Receiving an organ donation from a living donor is more desired than a deceased donor because it improves the chances of the recipient’s body accepting the donation. An organ from a living donor is also expected to last longer. The survival rate from a living kidney donor is about 26 years, according to the New York-Presbyterian Weill Cornell Medical Center. The survival rate for a kidney from a deceased donor is between 14 and 15 years.

Receiving a donation from a living donor also means a shorter wait time for the recipient and ensures the transplant can happen when the recipient is healthy, according to Johns Hopkins Medicine.

Someone is added to the national kidney waiting list every 14 minutes, according to the National Kidney Foundation.

On average, 13 people die each day while waiting for a kidney.

With a limited donor pool and a waiting list that grows each day, candidates often face long wait times for an organ. The average wait time for an organ from a deceased donor can range from three to 10 years.

New ways to find donors

Paired kidney donation has also led to different ways of finding donors, such as a non-simultaneous altruistic donor chain. The chain is started by an anonymous altruistic kidney donor, who gives his or her kidney to someone they don’t know. The donor’s kidney is given to a recipient that has a willing, but unmatched donor. That donor donates his or her kidney to someone else in the chain, and so on.

Since 2007, Rees said there has been an increase in people wanting to donate kidneys to strangers.

“You don’t have to die to donate an organ. You can donate your organ and live to see the good that it does because it’s a kidney and we have two of them,” Rees said. “We are very particular who we let donate a kidney, so that it’s safe if a doctor properly assesses you.”

In the beginning, there were many reservations in the transplant community before anonymous donations were accepted, according to Coates. But because the anonymous donors go through a rigorous medical and psychological screening the method has been embraced.

In transplant situations, Coates describes donors as “altruistic” because it benefits the recipient more than the person donating an organ. He says many do it because they just want someone to have another chance in life.

For more information, visit the Alliance for Paired Kidney Donation, the National Kidney Registry, or UNOS.