ESOT: Growing Acceptance for Kidney Transplants from Higher-Risk Donors

PRAGUE, Czech Republic, Oct. 1 -- Donated kidneys at the extreme end of acceptability because of donor age, storage time, or kidney condition may have good short-term outcomes, researchers said.

That's especially true if the donors are age matched and if steps are taken to reduce delayed graft function, said Rajinder Singh, M.D., of Wake Forest University in Winston-Salem, N.C., and colleagues in three studies presented here at the European Society for Organ Transplantation meeting.

"We're not going to make the claim that a kidney from an expanded criteria donor is going to last as long as a kidney from a standard criteria donor or younger donor," said Robert J. Stratta, M.D., of Wake Forest, who was the primary investigator on the studies.

But, he added, "if you pay attention to detail and chose your recipients wisely, you're not necessarily going to put your patients at any short term risk because they will have equivalent outcomes and, more importantly, you get them off the waiting list."

Long waiting lists have put pressure on the transplant community to optimize the use of organs from all consented deceased donors, Dr. Singh said.

An "expanded criteria" category for kidneys from deceased donors was created by the United Network for Organ Sharing in 2002. It allowed use of higher-risk organs from donors over age 60 or those over age 50 with health conditions such as high blood pressure, stroke, or poorer kidney function.

Dr. Singh's group retrospectively reviewed their single center experience with transplants from 80 "extreme" expanded criteria donors and 71 conventional extended criteria donors.

The "extreme" category encompassed donors who were over age 70, donated after cardiac death, had more than 30% glomerulosclerosis on biopsy, donated kidneys that were on cold ischemia longer than 30 hours, or had a creatinine clearance less than 60 mL/min.

"In the recent past, people were fairly dogmatic about refusing kidneys if they had any of these additional criteria," Dr. Singh said "The entire area is kind of a moving target right now."

They found that rates for patient survival (93%) and graft survival (85%) were similar between groups after an average 30 months of follow-up.

Delayed graft function, which requires temporary dialysis until the transplanted kidney begins functioning on its own, was more frequent in the extreme criteria group, but the difference was not significant (21% versus 13%, P=0.11).

Nor was there a significant difference in acute rejection, infection, reoperation, readmission, or initial length of hospital stay.

At one year, there was no difference in kidney function as measured by serum creatinine or Modification of Diet in Renal Disease glomerular filtration rate.

"Similar outcomes in extreme- and conventional-extended criteria donors suggest that the limits of acceptability for extended criteria donors in kidney transplant continue to evolve," Dr. Singh said.

But, "If you're going to use some of these donor organs that are on the edge of acceptability you have to be careful about choosing your recipients wisely," Dr. Stratta said.

In a separate study comparing extended and standard criteria donors, the researchers showed that donor-recipient age matching may improve outcomes.

Patients were considered age matched to their donors if those older than 60 received extended criteria donor organs and those 60 or younger received standard criteria donor organs.

Comparing the 243 age-matched patients to the 147 who were mismatched, the findings included:

• A higher mortality rate with age mismatch (9.5% versus 3.3%, P=0.012).
• A higher graft loss rate with age mismatch (18.4% versus 11.9%, P=0.10).
• Death-censored graft survival was not significantly greater when donor-recipient age was mismatched (90% versus 89%).

In another analysis of this same group of transplant recipients from standard and extended criteria donors, delayed kidney function was the major risk factor for graft loss among the 151 patients who received a kidney from extended criteria donors (OR 4.7, P=0.01).

One way to get around that risk is to use a pump to force fluid through the kidneys before transplant rather than leaving it sitting in cold storage, Dr. Stratta said.

"Pumping can reduce the incidence of delayed graft function," he said, particularly for extreme extended criteria kidneys.