Jack Burns and his wife, Adele, welcomed Doug Robertson with open arms. It was a very special reunion!

“I
didn’t know whether I was ever going to meet my recipient and I was
just thrilled that we could get together,” said Doug, who had traveled
from his home in Portsmouth, N.H., to meet Jack and his wife. Doug came
into Jack and Adele’s lives in 2010 when Jack, who has diabetes and high
blood pressure, needed a new kidney. Adele wanted to give him one of
her own. “I wanted to have my husband around and I knew that we didn’t
have a lot of options,” says Adele.

Jack
gets choked up thinking about what his wife sacrificed. “I was grateful
to have someone who loved me that much.” But, Adele was not a good
medical match to her husband. So, they joined a live-donor kidney
exchange program. She donated one of her kidneys to a suitable recipient
and Jack got a kidney from Doug. It can be much quicker than getting an
organ from a deceased donor.

“The
deceased donor wait list can be very long for people,” explains
Ruthanne Hanto, director of the Organ Procurement and Transplantation
Network (OPTN) Kidney Paired Donation pilot program, which is operated
under the United Network for Organ Sharing (UNOS). “If somebody brings a
living donor with them, then they have a great chance of getting
transplanted sooner.”

With
support from the National Science Foundation (NSF), Harvard University
economist Alvin Roth helped develop a suite of computer programs that
match living kidney donors with recipients. His team includes market
designer Itai Ashlagi and operations researcher David Gamarnik at MIT
and economists Utku Unver and Tayfun Sonmez at Boston College.

Together,
they developed an optimization program which looks at all the donors
and recipients in the program. “You look for ways to arrange those
exchanges so as to get as many of them as possible,” says Roth.

“A
combination of tools from the optimization theory, theory of graphs and
probabilistic methods enable building models which provide a unique
insight into the fascinating challenge of finding the right matches,”
explains Gamarnik. “Without these techniques, the practitioners face the
proverbial ‘finding-a-needle-in-a-haystack problem’ of searching
through the astronomic number of potential matches.”

“This
research is making it possible for one altruistic person to spark a
chain of donations, whereas before one kidney donor helped one person,”
says Nancy Lutz, program director for the Social and Economic Sciences
(SES) Division of NSF’s Directorate for Social, Behavioral and Economic
Sciences (SBE). “Now, someone associated with the first kidney recipient
then donates to someone else, and so on, kicking off a domino effect of
donations and matches. In addition, it’s especially rewarding to see
such a clear and immediate benefit to the public. This research moved
from abstract, academic theory to real world, direct impact very
quickly.”

Transplant surgeon Michael Rees at the University of Toledo Medical center is CEO of the Alliance for Paired Donation (see www.paireddonation.org).
“When I first got involved with kidney paired donation in 2000, I was
sitting at my kitchen table with the medical charts of 10 incompatible
transplant patients and it took me four hours to find just one 2-way
exchange. I knew then that I needed a computer to help find the
matches,” recalls Rees.

“But,
then Al and his team showed me that with just 600 incompatible patient
pairs, the maximum number of possible 2-way exchanges is about 180,000!
And, if you include multi-way exchanges and chains of transplants, the
best supercomputers in the world cannot find the best solution,”
continues Rees. “So, game theory and market design have come together to
find practical solutions for kidney disease patients. Their matching
software is the engine that has allowed us to help transplant centers in
30 states work together to create over 125 paired exchange kidney
transplants since 2007.”

So
what are economists doing organizing kidney transplants? It turns out
that an understanding of game theory and market dynamics is key to
optimizing pairings.

“If
you’re trying to organize an exchange, you need a marketplace and a
clearinghouse, and that’s what we tried to help our surgical colleagues
put together,” explains Roth. “Game theory turns out to be a giant thing
for thinking about big systems in which there are lots of different
incentives. The care of patients with kidney disease is a $100 billion a
year industry so there are lots of interests in it.”

“When
we started working on market design for kidney exchange, ad hoc
exchanges were being conducted sparsely in the country,” says Unver.
“Our experience in studying other allocation and exchange problems such
as dormitory room allocation in colleges helped us tremendously in the
design of centralized clearinghouses for kidney exchange. With the help
of health professionals, the ideas we developed were adopted, tested and
got refined in the field in various programs over the years. We
eventually hope to help thousands of patients per year.”

Think
of it as a medical version of match-dot-com, linking donors and
recipients, making chains of transplants possible across the country.
It’s all about streamlining complicated matches using the science of the
marketplace.

“Kidney
exchange is a powerful example of how research transforms into services
which have profound impact on our lives,” says Sonmez.

The software is comprehensive, matching participants with compatible blood types and antibodies.

“It
can put together an amazing string of different potential transplants
that you just could not do manually. It is an amazing computer system,”
explains OPTN’s Hanto.

“It
is the combination of research and practice that led us to understand
that using chains, exchanges that begin with an altruistic donor, vastly
increase the number of transplants for highly sensitized patients who
are difficult to match,” notes Ashlagi.

Jack, Adele and Doug talk about how the live kidney exchange program changed their lives.

“I’m
just grateful and lucky that this person was out there,” says Jack, as
he smiles at Doug. The two joke with each other. “How are you doing with
my old spare part,” asks Doug. “Your kidney is probably the healthiest
thing in my body!” chuckles Jack. “I was just hoping someone could use
an old kidney like mine,” laughs Doug.

Source: National Science Foundation