The swap, already done at a handful of U.S. hospitals, would involve patients who need transplants and have relatives or friends willing to donate but whose kidneys aren't a match. Each patient-donor pair would be matched with another pair to allow reciprocal transplants.
Creating a national "paired kidney exchange" would allow transplants for about half the 6,000 U.S. patients yearly who have willing donors with incompatible kidneys because of different blood types or other reasons, said Dr. Robert Montgomery, director of Johns Hopkins University's Comprehensive Transplant Center.
"The payoff is huge," said Montgomery, who organized a conference in Chicago where dozens of specialists gathered to develop a blueprint for a national paired organ exchange program.
There are more than 60,000 U.S. patients awaiting kidney transplants; last year 3,718 on the waiting list died because suitable organs couldn't be found in time, according to the National Kidney Foundation.
The average wait is three to four years, and while there are more living than deceased donors, most transplants involve deceased donor organs because two kidneys can be taken from each cadaver. Paired organ exchanges shorten waiting times and provide kidneys from live donors, which are preferred because they improve patients' chances of survival, Montgomery said.
Some 22 patients have received kidneys through the paired exchange program at Johns Hopkins, which began in 2001. Johns Hopkins also did the world's first known three-way swap, bringing six strangers together for simultaneous operations at the Baltimore hospital in 2003.
New England Medical Center and Medical College of Ohio are among other U.S. hospitals that take part in paired kidney exchanges. Conference participants included specialists from those institutions and the United Network for Organ Sharing, the national group contracted by Congress to coordinate transplants from cadaver donors to U.S. patients waiting for donated organs.
Governmental involvement would likely be required, Montgomery said, since UNOS is not contracted to allocate organs from living donors.
Despite logistic and ethical hurdles, a national organ swap program likely will be established and the Chicago conference is a step in that direction, said Sheldon Zink, director of the University of Pennsylvania's Program for Transplant Policy and Ethics.
"The transplant community and doctors and family members are desperate to get organs for people on the waiting list, and this is just another way in trying to do that," said Zink, who did not attend the conference.
Zink said she supports the concept but she said it needs to be implemented carefully, with safeguards to help make sure that donors aren't coerced into participating.
Also, transplant surgery is a major operation for donors and recipients, and recovery times tend to be longer and transplant-related emotional difficulties greater in donors who aren't closely related or live far from recipients, Zink said. She said those problems could be exacerbated by a national swap program.