A Better Method of Kidney Storage
WEDNESDAY Dec. 31, 2008 -- Pumping a solution continuously through a donated kidney raised the chances of a successful transplant when compared to simple cold storage of the organ, European researchers report.
The study, published in the Jan. 1 issue of the New England Journal of Medicine, got generally favorable reviews from American transplant experts.
It was hailed as "a landmark study" by Dr. Jonathan Bromberg, chairman of the Mount Sinai Medical Center Transplant Institute in New York.
"Machine perfusion has been performed for upwards of 20 years, and there has been a general perception among people in the field that it might do several important things -- better preservation of the kidney, clearing away toxins, giving data on whether the kidney is any good," Bromberg said. "But all the data until this have come from small, single-center retrospective studies. This is the largest and far away best to be done."
The European study, led by Dutch physicians, compared results of 336 transplants in which the donated kidney was subjected to hyperthermic machine perfusion to the same number in which the organs were kept in cold storage. Overall, the perfused kidneys did better once transplanted.
Delayed function of the transplanted kidney that required dialysis was seen in 70 cases where the organ was perfused, compared to 89 cases in the cold-storage group. Lower serum creatinine levels, a measure of better kidney function, was more common in the perfused organs. The one-year success rate for perfused organs was 94 percent, compared to 90 percent for the cold-storage group.
"This is clearly the best paper around," Bromberg said. "But you really have to look at the details and analysis of subsets of patients, and also at the economics. The study was not large enough to enable a subset analysis, and there was no economic or financial analysis at all."
Dr. John Fung, director of transplant services at the Cleveland Clinic, did his own financial analysis, which was not favorable for perfusion.
"To pump a kidney costs about $1,000 to $1,500," Fung said. "Is that added cost going to be offset by the benefits? If you look at the data, the reduced cost of dialysis and better survival at one year, they didn't answer that question."
The study will not change the Cleveland Clinic's use of perfusion, which is limited, Fung said. "We use cold storage for most kidneys," he said. "We use the pump for those kidneys we are not so sure about -- from older donors, those where the kidney function may not be as good, for example. We're selective about it."
And the study will not change the practice at Mount Sinai, which is governed by the rules of the New York Organ Donor Network, Bromberg said. "The overwhelming majority of kidneys transplanted in New York have been on the machine," he said. "Every now and then, we don't use it."
Still, the study does not provide definitive evidence about whether perfusion is necessary for all donated kidneys, Bromberg said.
The practice in New England is to use perfusion for "extended-criteria" kidneys, such as those from older donors or donors whose heart stopped beating before the kidney was removed, said Dr. Stefan G. Tullius, chief of transplant surgery at Brigham and Women's Hospital in Boston, who wrote an editorial accompanying the journal report.
"We will continue to do that," Tullius said. "But there will be greater emphasis on using perfusion with the report of this clinical trial."
The study showed "a significant reduction of delayed organ function, which is certainly a very unique finding, and this is the first trial showing it," Tullius said.
The basics of kidney transplantation are described by the U.S. National Library of Medicine.
Posted: December 2008