TUESDAY, Oct. 4, 2005 (HealthDay News) -- The best treatment option for someone with end-stage renal disease is to receive a "new" kidney from a living donor.
But the waiting lists for kidney transplants are growing longer. And even if a patient finds a willing live donor, that donor's organ is often incompatible and can't be transplanted.
However, a study appearing in the Oct. 5 issue of the Journal of the American Medical Association has found that cross-matching recipient/donor pairs had success rates comparable to live donor transplants.
If practiced more widely, the procedure, known as kidney paired donation (KPD) transplantation, could expand the available supply of kidneys, the study authors said.
In KPD transplants, two donor/recipient pairs exchange kidneys so that each needy recipient ends up receiving a compatible organ.
For example, patient A may have a willing donor in his friend, donor A. Unfortunately, that friend's kidney isn't compatible with patient A's body. And at another transplant center, a second patient, B, is facing the same dilemma with his friend, donor B.
But what if doctors could access a "living donor" database and discover that donor B's kidney is compatible with patient A? And what if that same database revealed a match the other way around -- with donor A perfectly matched to patient B?
A database like this -- that matched up willing, living donors across the United States with needy recipients -- could allow willing donors to save a loved one's life by "switching out" kidneys with a compatible recipient elsewhere.
"It's a very simple idea, but we needed to show that it worked and that the results were good," said study author Dr. Robert Montgomery, director of the Comprehensive Transplant Center at Johns Hopkins University School of Medicine in Baltimore. "It is something that can be done more widely if we can get buy-in from other institutions. Ideally, if there were a national program, we could optimize the number of these matches."
Other experts point out that the idea may be less simple in practice.
"All of us who see patients are for anything that will get us one more transplant," said Dr. Jonathan Bromberg, chairman of the Transplantation Institute at Mount Sinai Medical Center in New York City. "But there are a lot of logistical problems, working through issues of compatibility of donors and recipients, working through what percentage of the population has what particular blood type, issues of fairness. When you take all of those different ingredients and put them in a pot and stir them up, when you come out at the end of this, you can transplant a few people but not a lot."
Kidney donors and recipients can be incompatible in one of two ways: because of blood type incompatibility or because of human leukocyte antigens (HLA) antigen sensitization. Sensitization can occur in patients who had previously mounted an immune response against a foreign tissue (when pregnant, for instance, or during a previous transplant). The sensitization can cause a kidney to be rejected.
According to the study, there is a 36 percent probability that any two individuals will be blood incompatible, while about 30 percent of the patients on the deceased donor waiting list have HLA antigen sensitization.
Currently in the United States, 63,275 people are waiting for kidney transplants. The wait for a deceased donor organ can be as long as three to five years. The number of live donors has tripled over the last decade, making this the most common source of kidneys for transplants.
The new study followed 22 patients who received transplants through 10 kidney-paired donations. One was a triple exchange. After a median follow-up of 13 months, the patient survival rate was 100 percent and graft survival rate was 95.5 percent. One transplant was unsuccessful because the kidney failed, the researchers said.
The authors estimated that about half of the incompatible pairs in the United States could receive transplants if there were a national registry in place to match pairs. According to Montgomery, about 2,000 to 3,500 patients have living donors who are incompatible.
While a national network exists for deceased-donor kidneys, there is no such system for living donors.
Johns Hopkins has started its own registry.
Bromberg said that a donor exchange program in New York has yielded no transplants as of yet.
The potential problems, he said, ran from transportation issues to issues of liability and whether it's fair, for instance, to transplant a 30-year-old kidney into one patient while the other patient in the pair gets a 60-year old kidney. Or one living donor could contract an infectious disease right before the transplant surgery, he added.
More information
Learn about living kidney donations from the National Kidney Foundation.
