Featured Research

from universities, journals, and other organizations

National pilot program facilitates kidney paired-donation transplants

November 29, 2010
Carnegie Mellon University
A computer algorithm matched living kidney donors with medically compatible transplant candidates late last month as the national Organ Procurement and Transplantation Network (OPTN) began a national pilot program to increase the number of kidney paired-donation (KPD) transplants.

A computer algorithm developed at Carnegie Mellon University matched living kidney donors with medically compatible transplant candidates late last month as the national Organ Procurement and Transplantation Network (OPTN), operated by the United Network for Organ Sharing (UNOS), began a national pilot program to increase the number of kidney paired-donation (KPD) transplants.

The initial run of the computer matching process included just 43 kidney transplant candidates and 45 potential living donors, but a national KPD pool eventually could include as many as 10,000 donor-recipient pairs.

Each pair includes a potential donor who is not medically compatible with his or her original intended recipient, or is less than an optimal match. In the matching process, the computer looks for new combinations between the pairs based on compatible blood and tissue types. For example, in a two-way exchange, the donor from one pair is matched with a compatible recipient from a second pair, while the donor from the second pair is matched with the recipient from the first pair. In the initial run, three-way exchanges also were calculated.

Establishing a national pool could boost kidney transplants because the chances of finding compatible matches increase as the size of the exchange pool grows.

Smaller, existing kidney exchanges, which take these incompatible donor-recipient pairs and match them with other donor-recipient pairs, already have boosted the number of KPD transplants. In the last three years, exchanges have enabled more than 700 kidney transplants that otherwise would not have occurred. Two of those exchanges have used the Carnegie Mellon computer algorithm to match pairs.

"A unified nationwide exchange can yield significantly better solutions than multiple separate exchanges, and it is extremely rewarding that after we have worked on this for six years, the nationwide program is now live," said Tuomas Sandholm, a Carnegie Mellon professor of computer science who has led the development of computer algorithms for optimizing match runs.

The pilot program's initial computer run on Oct. 27 successfully matched seven people who need kidney transplants with medically compatible individuals who agreed to donate a kidney. Two of the seven candidates were highly sensitized because of previous exposure to donor antigens, which can make it particularly difficult to find donors with compatible tissue types.

"We are grateful both for Dr. Sandholm's expert consulting in developing our national pilot program and for the use of Carnegie Mellon's algorithm," said OPTN/UNOS President Charles Alexander. "These contributions have helped us develop the program more quickly and at significantly lower cost than we could have achieved otherwise, so we can focus on saving and enhancing lives through kidney paired-donation."

The need to increase the efficiency of kidney exchanges is compelling. The demand for donor organs -- more than 86,000 people are now on the kidney waiting list -- far exceeds supply. Last year, 28,463 people received kidney transplants, with 6,609 of those kidneys coming from living donors.

Examining all of the possible combinations of two- and three-way exchanges between the donor-recipient pairs is a massive computational task. The first algorithm that could solve this problem optimally on a nationwide scale -- a projected 10,000 pairs in the pool -- was developed in 2006 by Sandholm, Computer Science Professor Avrim Blum and then-graduate student David J. Abraham. The algorithm has since been further refined by Sandholm and Ph.D. students Pranjal Awasthi, Erik Zawadzki and John Dickerson.

The optimization problem places a huge demand on computer memory, Sandholm explained. Therefore, the algorithm never writes down the entire problem in the computer's memory. It nevertheless finds an optimal solution by formulating into memory only those parts of the problem that turn out to be relevant.

In the pilot phase of the nationwide program, 77 living kidney donor transplant programs are participating. Each is affiliated with one of four coordinating centers -- the University of Toledo's Alliance for Paired Donation, Johns Hopkins Hospital, New England Program for Kidney Exchange and the UCLA Medical Center/California Pacific Medical Center.

Computerized matching will be performed every four to five weeks with information on potential living donors and candidates supplied by participating transplant programs. Each transplant program must document that potential donors have completed a rigorous medical screening and evaluation process, and that they have provided detailed informed consent for donation and for potential participation in a national match run.

"In the future, kidney exchanges could be made even better by using our newest generation of algorithms that consider not only the current problem but also anticipate donors and patients who might later join the system," Sandholm said. "It can sometimes be best to wait on some of the transplants so that more or better transplants can be found as new pairs enter the system. Our new algorithms figure that out automatically using statistical properties of the blood- and tissue-type distribution of the population to generate possible sequences of additional pairs joining."

In addition to OPTN funding, the pilot project has been made possible by charitable support and in-kind donations from Carnegie Mellon, Sandholm, the New England Program for Kidney Exchange, EDS Consulting, Sommer Gentry and numerous private charitable foundations.

Work by Sandholm's team has been supported by the National Science Foundation and by the CMU Center for Computational Thinking, which in turn is supported by Microsoft Research.

Story Source:

The above story is based on materials provided by Carnegie Mellon University. Note: Materials may be edited for content and length.

Cite This Page:

Carnegie Mellon University. "National pilot program facilitates kidney paired-donation transplants." ScienceDaily. ScienceDaily, 29 November 2010. <www.sciencedaily.com/releases/2010/11/101116122859.htm>.
Carnegie Mellon University. (2010, November 29). National pilot program facilitates kidney paired-donation transplants. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2010/11/101116122859.htm
Carnegie Mellon University. "National pilot program facilitates kidney paired-donation transplants." ScienceDaily. www.sciencedaily.com/releases/2010/11/101116122859.htm (accessed July 31, 2014).

Share This

More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News


    Free Subscriptions

    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile

    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?

    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins