Lancet: Kidneys from cardiac-death equal to those from brain-death patients
For first-time kidney recipients, kidneys from controlled cardiac-death donors were equivalent to those donated from brain-death donors and had similar rates of graft survival and graft function, according to a study published online Aug. 19 in the Lancet.

“The demand for kidney transplantation far exceeds the supply of donor organs and the shortfall is becoming more severe as donor numbers fail to keep pace with increasing numbers of patients listed for transplantation,” the authors wrote. “A third of all kidneys from deceased donors in the U.K. are donated after cardiac death, but concerns have been raised about the long-term outcome of such transplants.”

To compare outcomes of kidneys donated from cardiac-death patients and brain-death patients, Dominic M. Summers, MD, of the University of Cambridge, in Cambridge, U.K., and colleagues evaluated 9,134 kidney transplants performed at 23 U.K. centers to assess factors that affect graft survival and function.

Kidneys donated subsequent to brain or cardiac death acquire variant degrees of injury including metabolic and hormonal disturbances after brain death and warm ischemia after cardiac death. According to the authors, warm ischemic injury can delay graft function in some instances, “suggesting that kidneys from cardiac-death donors are inferior to those from brain-death donors.”

Summers et al used the U.K. transplant registry to identify renal transplants from deceased donors between Jan. 1, 2000, and Dec. 31, 2007. The authors chose patients who received transplants from cardiac-death donors of Maastricht category III, defined as donors awaiting cardiac arrest after withdrawal of life-support treatment.

Researchers defined delayed graft function as having a need for dialysis after transplantation. All-cause graft function was taken at the time from transplantation to graft nephrectomy or return to dialysis. Graft function was measured from an estimated glomerular filtration rate.

The median follow-up for the study was six to 10 years and graft survival was assessed at five years.

Of the 9,134 recipients, 845 (9 percent) received kidneys from controlled cardiac-death donors, while 8,289 (91 percent) received kidneys from heart-beating brain-dead donors.

Cardiac-death donors were younger, more likely to be white and male and were less likely to have smoked compared to the brain-dead donors. Additionally, the most common cause of death in the donors was stroke, but this was more common in the brain-dead donors. Trauma was the most common cause of death for cardiac-death patients.

Patients who received kidneys from cardiac-death patients were older, less likely to have a prior renal transplant and received kidneys that were less well matched for human leukocyte antigen (HLA).

Primary non-function for patients who received kidneys from cardiac-death donors was higher for repeat than for first transplants.

The researchers found that delayed graft function occurred in 50 percent of kidneys from cardiac-death donors compared to 25 percent in kidneys from brain-death donors.

Additionally, acute rejection occurred in 17 percent of patients who received kidneys from cardiac-death donors and 24 percent of recipients who received kidneys from brain-death donors during the first three months after transplantation.

For first-time kidney recipients, graft survival up to five years after implantation was similar between both donors.

The researchers performed a Cox proportional hazards regression to control confounding variables.

They found that graft failure at five years was equivalent for first-time recipients of kidneys from cardiac-death donors (n=739) compared with brain-death donors (n=6,759).

Donors who were aged 60 or older held twice the risk of graft failure. Additionally, the researchers found that increased cold ischemic time was linked to inferior graft survival--graft failure doubled at a cold ischemic time of 12 hours of more.

The results also showed that cardiac-death donor kidneys that were poorly matched for HLA had an inferior outcome that was not significant and delayed graft function and warm ischemic time had no effect on outcomes.

“Widespread enthusiasm for expansion of kidney transplant programs that use controlled cardiac-death donors has been tempered by concerns that transplant outcome might be inferior to that with kidneys from brain-death donors, with a worryingly high incidence of primary non-function and reports of poor long-term graft function,” the authors wrote. “Our results show that for controlled cardiac-death donors, such concerns are unfounded: although kidneys from cardiac-death donors had a higher rate of delayed graft function than did those from brain-death donors, the incidence of primary non-function was similar in recipients of kidneys from both donor type, and graft survival and function did not differ between the donor types up to five years after transplantation.”

The researchers said that avoiding exposure to nephrotoxic immunosuppressive agents in the period after transplantation can be important, particularly if graft function is delayed.

“The factors shown to affect transplant outcome for kidneys from cardiac-death donors will help to guide clinical decision making and inform future allocation policy.”