Keep donor kidneys cool to stave off post-transplant dialysis in recipients, study says

Slightly lowering body temperature of deceased organ donors by as little as 2 degrees reduces the risk for post-op dialysis by nearly 40% in kidney transplant recipients—a finding that could help increase the availability of kidneys for transplant, according researchers and collaborators at University of California San Francisco (UCSF).

Their study appears in the July 30 issue of the New England Journal of Medicine.

Delayed function of donor kidneys (defined in this study as a recipient’s need for dialysis within 7 days after renal transplantation) occurs in up to 50% of renal allografts recovered from deceased donors, and leads to increased costs and reduced long-term graft function.

Current protocols require that organ donors be maintained at normal body temperature. Lowering body temperature—termed therapeutic hypothermia or targeted temperature management—is a common practice in patients with certain types of cardiac arrest, stroke, and asphyxia to protect neurologic function.

The authors of this article pointed to an earlier retrospective study of patients with cardiac arrest that showed mild hypothermia appeared to protect against renal injury.

So, in their study, the investigators passively cooled body temperature in deceased organ donors (34°-35°C) from normal body temperature (36.5°-37.5°C). This slight, 2-degree change demonstrated a 38% increase in the successful function of donated kidneys after surgery. In fact, the researchers stopped the trial early when an interim analysis demonstrated the overwhelming efficacy of therapeutic hypothermia.

“This is a free intervention that can be done at any hospital in the world, and tens of thousands of patients worldwide can benefit from it,” said co-lead author Claus Niemann, MD, professor of anesthesia and surgery at UCSF.

A total of 572 patients in this study received kidney transplants—287 from donors in the normal body temperature group and 285 from donors in the hypothermia group. Delayed graft function developed in 112 (39%) of the normal body temperature group compared with 79 (28%) of the hypothermia group.

Kidneys from “extended criteria donors” and other high-risk subgroups especially benefited from therapeutic hypothermia. These included older donors or donors who had health issues that previously would have excluded use of their organs.

“From these findings, potentially more organs could be available for transplantation since we can push the limits with these ‘marginal donors’,” Dr. Niemann said. “This is critical because the number of available deceased organ donors has been stagnant, but the demand has dramatically increased. In the United States alone, about 101,000 patients wait for kidney transplantation.”

This finding “could have a major impact on global health, especially in resource-limited countries, and provide significant cost savings in the United States through less dialysis, shorter hospital stays, and potentially less need for expensive interventions,” Dr. Niemann said.

In an editorial in the same issue, transplant specialists Ina Jochmans, MD, PhD, of Belgium, and Christopher J.E. Watson, MD, of the UK wrote: “The results reported here will be welcomed for many reasons, not least of all because they have shown that, in this era of high-technology medicine and targeted drug therapy, it is still possible to identify a simple, cheap intervention that can have dramatic therapeutic effects.”