Marginal Kidneys Are Okay
They are comparable to ideal donor kidneys with respect to outcomes.
Patients who receive a kidney from a marginal donor, however, have significantly reduced graft function, as measured by glomerular filtration rate, at one, two, and three years post-transplant.
The findings are based on a retrospective chart review of all patients transplanted at a single institution between September 1998 and March 2003. All the patients received basiliximab induction followed by a maintenance regimen that included cyclosporine microemulsion, mycophenolate mofetil, and prednisone.
The investigators defined marginal donors as either expanded donors (based on a definitions estimated by the United Network for Organ Sharing) or non-heart beating donors. Forty patients received a kidney from a marginal deceased donor and 100 patients received a kidney from an ideal deceased donor. The two groups were then assessed for patient and graft survival and GFR, which was determined using the modified Modification of Diet in Renal Disease study equation at one, two, and three years post-transplant.
The two groups were similar in their gender ratios, time on dialysis prior to transplant, and incidence of delayed graft function. The mean number of months on dialysis for the patients receiving kidneys from an ideal or marginal donor was 24 and 25 months, respectively. Delayed graft function occurred in 47% of patients receiving an ideal donor kidney and 55% of patients receiving a marginal donor kidney. The two groups also were found to be relatively similar in terms of the percentage of CMV positive donors (52% for ideal donors, and 62% for the marginal donors) and CMV positive recipients (50% and 67% of recipients of kidneys from ideal and marginal donors, respectively). The mean cold ischemia time was 20 hours in both groups.
The rejection rate was 14% and 15% for recipients of ideal and marginal kidneys, respectively, the investigators reported here during Renal Week 2006. The survival rate of patients who received an ideal donor kidney was 95% at one year, 94% at two years, and 90% at three years; the rates for those who received a marginal donor kidney were 93%, 89%, and 81%, respectively. The differences between the groups were not statistically significant. Graft survival rates for recipients of ideal donor kidneys were 90% at one year, 89% at two years, and 86% at three years. The rates for the recipients of marginal donor kidneys were 87%, 85%, and 84%, respectively.
The mean GFR for the ideal donor kidney recipients was 57 mL/min at one year, 56 mL/min at two years, and 54 mL/min at three years; for the recipients of marginal donor kidneys, the mean GFR was 44, 40, and 39 mL/min, respectively.
“We found that these marginal deceased kidneys should be used,” said study investigator James Hartle II, MD, director of nephrology at the
The marginal donors were significantly older than the ideal donors (mean 59 years vs. 33 years), and the recipients of marginal donor kidneys were significantly older than the recipients of ideal donor kidneys (mean 58 years vs. 48 years).
The study should be of particular interest to nephrologists because the continued shortage of kidney donors has led to a greater use of marginal deceased kidneys, Dr. Hartle observed. Large-scale database analyses have confirmed the benefits of marginal deceased kidney usage over maintenance dialysis. Dr. Hartle said, however, that there has been a lack of studies looking at the usage of marginal kidneys in terms of specific immunosuppressive regimens.