The use of kidneys from deceased donors should not be discouraged solely on the basis of age.
PRAGUE—New studies presented at the 13th Congress of the European Society for Organ Transplantation suggest that transplant surgeons can make more effective use of kidneys from deceased donors, even from donors at the outer limits of acceptance criteria.
“Our experience suggests that the limits of donor acceptability may continue to expand as we are able to achieve acceptable short-term results with kidneys that once would have been discarded,” said senior researcher Robert Stratta, MD, professor of surgery and director of abdominal transplantation at Wake Forest University Baptist Medical Center in Winston-Salem, N.C.
“Our findings point to the importance of matching donor and recipient ages, reducing waiting times for transplantation, and taking steps to reduce delayed graft function and acute rejection.”
Dr. Stratta and his colleagues conducted a retrospective study comparing results using expanded criteria donor (ECD) organs with what they term “extreme” ECD organs. The ECD category was created by the United Network for Organ Sharing (UNOS) in 2002 so higher-risk donor organs once considered unsuitable could be transplanted safely. The ECD category includes kidneys from deceased donors over age 60 or those over age 50 with health conditions such as hypertension, stroke, or elevated creatinine levels.
For this study, extreme donors were ECDs with any of the following additional criteria: deceased donor age above 70, donation after cardiac death (DCD), greater than 30% glomerulosclerosis on biopsy, cold ischemia time (CIT) greater than 30 hours, or calculated deceased donor creatinine clearance of less than 60 mL/min per 1.73 m2.
A total of 80 extreme ECD and 71 conventional ECD kidney transplants were performed between October 2001 and February 2007. The mean age of the deceased donor was 63.3 years in the extreme ECD group and 59.2 years in the conventional ECD group. The mean CIT was 26.4 and 21.1 hours for the extreme and conventional ECD groups, respectively. The deceased donor creatinine clearance, however, was significantly lower in the extreme group (68 vs. 87 mL/min per 1.73 m2). Dr. Stratta said other characteristics were similar.
After a mean follow-up of 30 months, patient and graft survival rates were found to be similar in the two groups (93% and 85%, respectively). The rate of delayed graft function was higher in the extreme group than in the conventional group (21% vs. 13%), but no significant differences were observed in the one-year serum creatinine levels (mean 1.8 mg/dL) and glomerular filtration rate (mean 42 mL/min per 1.73 m2). No significant differences were ob-served in the rates of acute rejection (11%), infection, re-operation, readmission, initial length of stay, and resource utilization.
“You should not discard organs based solely on a donor’s age,” Rajinder Singh, MD, a transplant
fellow at WFUBMC, told Renal & Urology News. “If a donor is above age 70 then that should not be the only reason to exclude them. You need to look at other factors as well.”
Dr. Singh, who presented the findings at the meeting, said this study and two others by his research group suggest that it is important to take a look at the donor on many different levels. He said considering only one issue such as advanced chronological age is a mistake.
In a second study, this same group looked specifically at whether there is an advantage to matching the ages of donors and recipients. This study, which involved 243 kidney transplant patients, compared re-sults when ECD kidneys were transplanted into older recipients and standard criteria donor (SCD) kidneys from younger donors (under age 60) were transplanted into younger recipients. These two groups were compared with similar groups in which donor and recipient age-matching did not occur.
Mortality was higher (9.5%) in the age-mismatched group compared with the age-matched group (3.3%). The difference held true regardless of whether the donors and recipients were older or younger than age 60. “Donor and recipient age-matching in deceased donor kidney transplants may confer a survival benefit that is independent of recipient age,” Dr. Stratta said.
In a third study, the researchers sought to identify risk factors for kidney graft failure. They reviewed 56 cases of graft failure in 390 patients who received kidneys from deceased donors. The researchers found that 29 of the failed organs were from SCDs and 27 were from ECDs. The risk factors for graft loss in both groups included diabetes in the recipient, recipients older than 60 years, episodes of acute rejection, or delayed graft function.
“We were surprised that both groups did equally well,” Dr. Stratta said. “So, it tends to dispel some of the myths of the usability of a given donor. Although donor age is the single most important variable in determining donor quality it is more important to try to get a grasp on the physiologic age as opposed to the chronologic age. That is not always easy to do. Some people age gracefully and some people don’t. We try to determine their physiologic age based on medical and physical characteristics, history, and kidney function. Once the kidneys are removed, we also look at anatomy and the biopsy and we often put the kidneys on a pump so the pump numbers can give us some idea on the viability of the kidneys.”
The similar outcomes in extreme ECDs and conventional ECDs suggest that limits of acceptability for ECDs continue to evolve in terms of kidney transplants, he noted.
“These extreme donors are worth using,” said Martin Jendrisak, MD, assistant professor of surgery at Washington University School of Medicine and the surgical director of the kidney program at Barnes-Jewish Hospital in St. Louis. “We need to look at extended and extreme donors more and use more of them if we can because the demand is growing so fast. The number of kidney patients be-ing added to the wait list is growing every year. Age becomes an issue in that we know after age 40 you start losing nephron mass. But it is not the most important thing to look at. Instead, it is the patients’ physiology that you should look at and examine their other health issues.”
The new studies by the Wake Forest team are clinically important and should help lead to a more expanded use of ECDs and extreme ECDs, Dr. Jendrisak said. “It is always good to try to maximize the gift of organ donation,” he said. “It is delicate balance with having the patients wait. You have to ask if it is in their better interest for a more viable organ or using one from an extended or extreme donor. They may not have the ability to wait too long because their health may be deteriorating on dialysis. A 25-year-old patient may be able to wait as opposed to someone who is already age 70, so it may be more appropriate in older patients.”