For more than 100,000 patients in the U.S., their life depends on finding an organ to replace a damaged or diseased one. In the never-ending tug between organ supply and demand, the scales have never tipped in favor of the patient; only a fraction of the people needing a new kidney, liver or heart actually receive one. To move people off the organ-waiting list, doctors either have to boost the supply of donors, or improve the viability of existing organs.
Researchers from the Netherlands report in the New England Journal of Medicine that they have found a way to increase the chances that kidneys from deceased donors will succeed after transplant, thus sparing patients from expensive follow-up care or even another organ transplant. In the largest and first study of its kind, doctors compared two existing ways of preserving kidneys taken from deceased donors in cold storage in an ice pack, or via cold perfusion, which involves hooking the kidney up to a machine that pumps a chilled blood-like solution throughout the organ. (See the top 10 medical breakthroughs of 2008.)
At the end of a year, 94% of the kidneys that were perfused had survived once transplanted, compared with 90% of the cold-stored kidneys. More significantly, 26% of the cold-stored organs failed to function in the first weeks after transplant, compared with only 21% of the kidneys that were perfused. While the differences were small, say experts, they can be significant when you consider the costs of dialysis and follow-up care for failed transplants. "Four percent may not appear to be a lot, but if this difference persisted across the country, that would be a significant cost benefit on behalf of the patient," says Dr. Bryan Becker, president of the National Kidney Foundation. "I think this study is a big step toward using available technology to optimize the kidneys that are donated today."
Currently, about 62% of kidneys transplanted each year in the U.S. are harvested from deceased donors; many of those organs cannot be transplanted if they aren't correctly preserved. Past studies have shown that a kidney must be transplanted within 24 hours to lessen the risk of failure in its new host. Most organ centers handle kidneys pre-transplant by washing, then submerging them in a preservation solution and melting ice. But recent evidence has suggested that perfusion machines, which have been around since the 1970s, might do a better job of maintaining the organs and perhaps promote survival once they are transplanted.
So Dr. Rutger Ploeg, professor of surgery at the University Medical Center of Groningen in the Netherlands, set up a trial involving patients from the international organ exchange group called Eurotransplant. Researchers procured a pair of kidneys from 336 deceased donors and, within 24 hours, placed one from each pair in cold storage, and attached the other to a LifePort Kidney Transporter perfusion machine. The kidneys were then transplanted into 672 recipients. Among the patients who received a cold-stored kidney, 89 developed a condition called delayed graft function in which the kidney fails to function immediately after transplant. Only 70 of the machine-preserved kidney patients developed the complication meaning that the perfused kidneys had 12% better graft survival than those in cold storage. "Normally, in transplantation, we know within the first two weeks whether the transplant is good or bad. So we already see a huge difference," says Ploeg.
Ploeg notes that these results should help doctors make the most of the kidneys that are currently available. Ploeg's study found that machine-preserved kidneys performed consistently better than cold-stored kidneys no matter who the donor. In other words, perfusion proved beneficial, even when the organ donor was older or had other issues that would make the tissue marginal for transplant. That's especially important, since in recent years, the quality of donated kidneys has declined, due in part to the typical donor's advanced age and increase in accumulated health problems and diseases. Given the dwindling of an already small pool of viable organs, many patients are choosing to obtain kidneys from living donors usually close relatives, who must undergo an extremely invasive and dangerous operation to donate the organ. But machine preservation, if used more widely, could help curb that trend, says Ploeg. "When we have good kidneys from deceased donors, we don't have to harm a living donor," he says.
About half of U.S. transplant organ facilities currently have perfusion machines, according to estimates by the National Kidney Foundation, something that may change based on the results of the new study. "If we can take the kidneys that we have and increase the likelihood that they will work [better], then that's going to be marvelous," says Becker of the National Kidney Foundation. And, if the study results hold, that benefit could extend to other transplant tissue as well. "We're going to see interest in utilizing this principle for other groups of organs," says Dr. Stefan Tullius, chief of transplant surgery at Brigham and Women's Hospital in Boston. "That's part of the value of this study."