Acute Kidney Injury May Not Preclude Transplant

Laurie Barclay, MD

March 11, 2015

In light of reasonable 6-month graft function, clinicians should consider kidney transplant from deceased donors with acute kidney injury (AKI), according to a multicenter study published online March 11 in the American Journal of Transplantation. However, there are risks for kidney discard and delayed graft function (DGF), defined as the need for continued dialysis support in the first week after transplantation.

"There appears to be room to attempt more transplants using these AKI kidneys rather than throwing them away," senior author Chirag R. Parikh, MD, director of the Program of Applied Translational Research at Yale University School of Medicine, New Haven, Connecticut, said in a university news release.

"The waiting list has grown to over 100,000 patients as thousands more people are wait-listed each year than actually receive a transplant. In addition, the median time it takes for an adult to receive a transplant in the United States increased from 2.7 to 4.2 years between 1998 and 2008, and more than 5,000 people die each year while waiting for a kidney," Dr Parikh continued.

Using a sample of 1632 donors, Isaac E. Hall, MD, from the Program of Applied Translational Research, Department of Medicine, Yale University School of Medicine, and colleagues examined associations of AKI, defined as increasing admission-to-terminal serum creatinine, with kidney discard, DGF, and 6-month estimated glomerular filtration rate (eGFR).

Compared with donor kidneys with no AKI, kidneys with AKI Network stages 1, 2, and 3 had increased kidney discard risk. Adjusted relative risks were 1.28 (95% confidence interval [CI], 1.08 - 1.52), 1.82 (95% CI, 1.45 - 2.30), and 2.74 (95% CI, 2.00 - 3.75), respectively.

Donor AKI stage was also linked to risk for DGF, with adjusted relative risks of 1.27 (95% CI, 1.09 - 1.49) for stage 1, 1.70 (95% CI, 1.37 - 2.12) for stage 2, and 2.25 (95% CI, 1.74 - 2.91) for stage 3.

Surprisingly, however, AKI was not linked to poor kidney transplant function 6 months later, and AKI stages did not differ significantly in terms of 6-month eGFR. However, recipients with DGF had significantly lower 6-month eGFR (48 mL/minute per 1.73 m2; interquartile range, 31 - 61 mL/minute per 1.73 m2) than those without DGF (58 mL/minute per 1.73 m2; interquartile range, 45 - 75 mL/minute per 1.73 m2; P < .001).

There was a significant, favorable interaction between donor AKI stage and DGF. Six-month eGFR increased in tandem for DGF kidneys with increasing donor AKI (P for interaction = .05).

"What we saw was, with worsening AKI in the donor, the six-month outcome was actually better for recipients who experienced DGF," Dr Hall said in the news release.

A possible explanation offered by Dr Hall was that kidneys acutely injured in the donor may develop ischemic preconditioning, which could protect the organs from later injury. Alternatively, the successfully transplanted kidneys with AKI may have been of better quality otherwise than the rejected kidneys with AKI, despite adjustment for donor age, comorbidity, and other clinical factors.

The authors note several study limitations, including its observational design with possible residual confounding and lack of complete follow-up data beyond 6 months. Nonetheless, the study authors suggest considering cautious expansion of the donor pool to deceased donors with AKI.

"Even if it only means a few dozen more kidney transplants each year, those are patients who would come off of the waiting list for transplants sooner and have much better survival than continuing on dialysis in hopes of seemingly higher-quality kidney offers, which may never come in time," Dr Parikh said in the release.

The American Heart Association and the National Institutes of Health supported this study. Dr Parikh received a Roche Organ Transplantation Research Foundation Award. The other authors have disclosed no relevant financial relationships.

Am J Transplant. Published online March 11, 2015. Abstract

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