Matching method helps doctors successfully transplant higher-risk kidneys

By carefully matching the estimated function of kidneys from deceased donors with the needs of potential recipients, surgeons can successfully transplant kidneys that would otherwise be discarded, according to a report from Wake Forest University Baptist Medical Center. The center was able to double its transplant volume within a year.

In addition, a second report concludes that age alone shouldn’t prohibit older adults from being organ donors – or having a kidney transplant themselves – success rates are similar in older and younger patients.

“There is a critical shortage of kidneys for transplantation, which puts us in the difficult situation of rationing organs,” said Robert Stratta, M.D., director of Transplantation Services at Wake Forest Baptist. “Newer ways to match organs to recipients allow us to use kidneys that once were considered unsuitable.”

In the May issue of Annals of Surgery, Stratta and colleagues reported on their experience using kidneys under a new system that was implemented by the United Network for Organ Sharing (UNOS) in 2001. It allows the use of kidneys from deceased donors over age 60, as well as from donors over age 50 with at least two of the following: high blood pressure, fatal stroke, or certain levels of a protein called creatinine. Levels of creatine, which is produced by muscle, are used to determine kidney function.

Using kidneys from these donors, which UNOS calls expanded criteria donors (ECDs), permits more patients to benefit from transplantation, Stratta said, without affecting either patient survival or short-term survival of the transplanted kidney.

Transplant centers across the nation are working to determine how to use the organs most effectively. Wake Forest Baptist’s approach is to estimate the function of a donated kidney and to match it with the needs of a potential recipient.

“In the past, kidneys were matched exclusively by blood and tissue type,” said Stratta. “Now, we are matching based on age, weight and kidney function. Someone who weighs less doesn’t need as much transplanted kidney capacity; it is a concept that is in evolution.”

Stratta and colleagues compared survival rates and other measures of success in 53 patients who received kidneys from standard criteria donors (SCDs) and 37 patients who received kidneys from ECDs. Patients were followed for an average of 16 months. Patient and kidney graft survival rates were similar between the two groups.

“The use of ECD kidneys at our center doubled our transplant volume within one year,” said Stratta. “A systematic approach to matching ECD kidneys that is based on kidney function seems to provide short-term outcomes that are comparable to SCD kidneys.”

The transplant team will continue to follow these patients to assess long-term kidney function and survival. Stratta believes that with careful patient selection, the kidneys from expanded criteria donors may function for as long as kidneys donated under the standard criteria, about eight to 12 years.

Stratta and colleagues are also studying the issue of transplantation and the aging American population. There are more elderly kidney donors, as well as older adults who need kidney transplants, than ever before.

“Controversy exists regarding the optimal approach to the elderly donor or recipient,” said Stratta.

In a separate study of 129 transplant patients who received kidneys from deceased donors, Stratta and colleagues compared 96 patients ages 19 to 59 to 33 transplant patients who were 60 years of age and older.

“An average followup of 17 months showed no difference in patient survival or kidney survival,” said Stratta, who reported the results today at the American Transplant Congress in Boston. “You can no longer make the argument that transplanting a kidney into an older recipient is a wasted organ.”

About 66 percent of patients in the older group received kidneys from ECDs, compared to 30 percent of patients in the younger group.

“The older group did equally well, in spite of the fact that they usually received kidneys from older donors,” said Stratta, who has performed transplants in patients as old as 76.

Patients receiving the ECD kidneys did have slightly higher rates of viral infection, which could affect hospital readmission rates, and this finding needs to be explored, said Stratta.