Despite being a vital source of kidneys for transplantation, donation after circulatory death (DCD) is underutilized and less common in the United States. New research shows that DCD kidneys may be as viable as kidneys from other donors, and that accepting more DCD donor kidneys may reduce discard rate.

The diseased donor kidney discard rate has been increasing for at least 20 years, starting at 5.1 percent in 1988 and rising steadily to a high of 19.1 in 2009. This trend occurred at a time when the number of kidneys nearly doubled, skyrocketing from 7,705 to 14,394. The discard rate stabilized between 2010 and 2015, settling at 18 to 19 percent.

Researchers have recently revealed a way to minimize DCD kidney damage and improve preservation of the organs for transplantation. They study, published in the Journal of the American Society of Nephrology (JASN), found that more kidneys from DCD donors are discarded, compared with the number of kidneys procured from neurologically brain dead (NBD) donors.

The team, led by John Gill, M.D., of the University of British Columbia in Vancouver, looked at national data from 2008 to 2015. They found that a quarter of donor service areas recovered fewer than 10 DCD kidneys annually. Some donor service areas were more amenable to procuring DCD kidneys: just four of the 58 donor service areas procured a full 25 percent of all accepted DCD kidneys. Donor service areas discarded 1 in 5 DCD kidneys, with discard rates ranging from 3 to 33 percent among donor service areas.

Clinicians discard more DCD kidneys than those from neurologically brain dead (NBD) donors. The researchers noted that refusal was more common for DCD with longer warm ischemic times, with total warm ischemic time beginning upon withdrawal of life support and lasting until the onset of cold perfusion. Compared with NBD kidneys, the odds of discard were 1.3 and 2.7 times higher for DCD kidneys, with total warm ischemic times of 10 to 26 minutes and more than 48 minutes, respectively.

DCD allografts are associated with promising survival rates, with 75 percent of recipients surviving for at least five years after receiving a transplant. Among the 12,831 DCD kidneys transplanted, survival rates for those receiving kidneys with total warm ischemic times of 48 minutes or less were similar to NBD kidneys.

The risk for allograft failure increased by 23 percent when warm ischemia was longer than 48 minutes, but only in instances where cold ischemia time was longer than 12 hours. The researchers noted that reducing cold ischemia time might prevent injury and improve results.

"We found that use of DCD kidneys is variable throughout the United States, that the outcomes are generally excellent, and that the use of these organs could probably be safely increased if cold ischemia times are limited," Gill commented in a release from the American Society of Nephrology, the publishers of JASN.

The authors of the study concluded that there are significant variations between donor service area-level in the recovery and discard of DCD kidneys. They also call for the collection of more national data to help researchers understand the potential for increasing DCD donor transplantation in the U.S.

The researchers suggest investigating strategies to minimize cold ischemic injury in ways that allow increased use of DCD kidneys with warm ischemic times greater than 48 minutes.