According to current estimates, 95,000 patients with end-stage renal disease (ESRD) in the United States who have cleared medical evaluations to receive a deceased donor kidney remain on the waiting list. Approximately 9,000 of these patients are removed from the waiting list each year due to death or deteriorating health. However, the need for donor kidneys is rising by 8% per year but their availability has not grown at the same rate to match the need. Researchers have proposed using kidneys from deceased donors with acute kidney injury (AKI) to potentially help reduce the shortage of these organs.

In some clinical settings, AKI and chronic kidney disease (CKD) are seen as interconnected, but AKI in the setting of deceased donor transplant may not be comparable. A variety of factors can lead to serum creatinine (SCr) fluctuations that meet criteria for AKI in deceased donors who typically do not have CKD, severe cardiovascular disease, or sepsis. “AKI may be a manageable issue in the context of organ donation,” explains Chirag R. Parikh, MD, PhD.

A New Study Analysis

Recent clinical trials support the cautious use of select kidneys from deceased donors with AKI, but current allocation practices of such kidneys by organ procurement organizations have not been well characterized. “Currently, the national discard or rejection rate for all potential donor kidneys is approximately 18%, but this rate increases to 30% for AKI kidneys,” says Dr. Parikh. For a study published in JAMA, Dr. Parikh and colleagues mimicked a clinical trial using registry data to match deceased donors with and without AKI. They evaluated the association of deceased donor AKI with recipient graft survival and then characterized current recovery and discard practices of AKI kidneys across the country.

Kidneys from 13,444 deceased donors were transplanted into 25,323 patients with ESRD in the U.S. from 2010 to 2013. Of these, 12,810 received kidneys with AKI and 12,513 were given kidneys without signs of AKI. Each AKI kidney was paired at the beginning of the study with a non-AKI kidney using a statistical method that mathematically linked several donor characteristics, including age, sex, ethnicity and medical conditions other than AKI. Transplant recipients were followed for 4 to 6 years after surgery.

Highlighting Important Data

The study revealed that deceased donor AKI status had no association with death-censored or all-cause graft failure (Table). “Our key finding was that that deceased-donor AKI had no association with either short-term or long-term survival of the organ,” says Dr. Parikh. AKI kidneys transplantations had comparable rates of recipient graft survival, even among the highest stages of injury. Results were consistent after examining by AKI stage and adjusting for recipient and transplant characteristics. More recipients of AKI kidneys developed delayed graft function (29% vs 22), but few recipients developed primary nonfunction, regardless of deceased donor AKI status.

To determine how many potentially viable kidneys with AKI were lost during the study, the authors assessed how many deceased donor kidneys with AKI were recovered and then either transplanted or discarded. Nearly 17,500 of the more than 20,500 available AKI kidneys were procured over the 3-year study, but only slightly more than 12,700 were transplanted. “This means almost 8,000 organs were either rejected after procurement or never obtained at all simply because the donors had AKI,” Dr. Parikh says.

Expanding the Pool

The study findings strongly support the idea that kidneys with AKI should be actively procured and transplanted. “Our results suggest that the transplant community should consider cautiously using deceased donor AKI kidneys to expand the donor pool,” says Dr. Parikh. “Future investigations should determine if currently discarded AKI kidneys from deceased donors without substantial comorbidities can be used more effectively. For example, it is possible there is a labeling effect of SCr on the kidney quality score that may lead to discarding AKI kidneys when they may actually be usable for patients with kidney disease.”