Adult kidney transplant recipients who receive a single kidney from a very young, deceased donor may do just as well in terms of life expectancy and organ function as those who are given both kidneys, new research has found.
The finding is centered on the controversial issue of how to handle kidney transplants coming from donors 5 years of age or younger, and raises new questions about the common assumption that such kidneys must be transplanted in unison to be viable.
Currently, kidneys taken from children 5 years of age or younger are typically kept together and transplanted as a set into adult recipients, the idea being that splitting up such tiny pediatric organs could undermine the success of the transplant.
By contrast, kidneys taken from donors 10 years of age or older are usually deemed separable. There is no clear protocol regarding kidneys from deceased children between the ages of 5 and 10.
But the new finding suggests that adult patients may fare equally well after receiving just one kidney from a very young donor — an observation that could prove auspicious for the approximately 80,000 Americans currently awaiting a kidney transplant.
“Basically, the normal practice of giving two small kidneys to an adult is unnecessary,” said study author Dr. Rubin Zhang, medical director of kidney and pancreas transplantation at the Tulane University Abdominal Transplant Institute in New Orleans. “It just doesn’t make sense to think of this as if two function better than one, because even though a pediatric kidney will grow larger over time everything else about it in terms of its function is there and fixed at birth. So transplanting two is wasting a lot of kidneys.”
The findings will be published in an upcoming issue of the Clinical Journal of the American Society of Nephrology.
The notion that a single pediatric kidney transplant might be as effective as a double transplant has huge implications, given that an estimated 4,000 American men and women with kidney disease die before a suitable organ becomes available, according to background information in the study.
To assess the viability of single pediatric kidney transplantations, the study authors tracked 79 adult kidney recipients who were patients at Tulane University Abdominal Transplant Institute between 1996 and 2007. During that time, all the adult patients received just one kidney from a deceased donor who was 10 years of age or younger.
Half the adults were given a single kidney from a child between the ages of 5 and 10, while the other half received a kidney from a child who was under the age of 5 — the youngest donor being a 9-month old female.
By most measures, the two groups fared equally well, regardless of the age of the donor child. Both groups were similar in terms of the need for additional surgery following the transplant due to complications, and both experienced comparable rates of kidney rejection and kidney function delays.
Also, kidney function improved along the same trajectory among both groups of recipients during the first three years following transplantation, and both had similar survival rates following surgery.
Zhang and his colleagues noted that the two kidneys from the 9-month-old donor remained healthy and functioning six years after they were transplanted into two separate patients.
The researchers did find that nearly twice as many recipients of kidneys from children younger than 5 had to undergo a urine-drainage procedure following transplantation.
But, the study authors concluded that single kidney transplants from children younger than 5 years old are safe and effective.
Zhang said that he views his finding as definitive, and suggested that “no matter how young the donor — even less than one year — one kidney transplant is enough.”
Dr. Jeremiah Lowney is an internist and medical advisor to a Canton, Mass.-based not-for-profit group called MatchingDonors.com, which seeks to give people in need of transplant surgery an “active way to search for a live organ donor,” according to its Web site. He called the new findings “fantastic news,” while noting that every day approximately 17 Americans die while awaiting a kidney transplant.
“So what we have right now in renal [kidney] transplantation is a supply problem,” Lowney explained. “And it’s actually been getting worse over the years, as the numbers continue to grow. So this study offers a lot of hope, in that this might be one way we can increase the supply of kidneys, and certainly help many more people who are already waiting for a transplant.”