The study by the radiology and transplant teams at UC Davis Health System is the first to evaluate a number of en bloc transplants that involve giving two kidneys from a very small (under 5 kilograms, or 11 pounds) donor to an adult recipient to determine the occurrence of GAS, which causes blood vessels to constrict and risk the longevity of the graft.
“It’s been assumed that complication rates are relatively high for en bloc grafts,” said study lead author Ghaneh Fananapazir, assistant professor of radiology and a specialist in abdominal imaging. “We found the opposite to be true for this particular complication.”
Published online in the American Journal of Transplantation, the outcome highlights the importance of using kidneys for transplant from even from the smallest donors, which can also provide some solace to the parents of children who, in death, give those with end-stage kidney disease a new lease on life.
“Every possible kidney that can be utilized for transplant should be utilized for transplant,” said senior study author Christoph Troppmann, professor of transplant surgery. “It reduces time on dialysis and significantly extends life.”
The reported incidence of post-transplant GAS in single adult transplants varies widely — between 1 and 23 percent — with the highest risk for transplants involving kidneys from deceased instead of living donors and from pediatric instead of adult donors. Prior to the current study, the risk of GAS following en bloc transplants was unclear.
Fananapazir and his team evaluated the medical records of 182 adult transplant patients at UC Davis who each received two kidneys from very small donors between January 2005 and February 2014. Ultrasound screening following the surgeries identified GAS in only 1.1 percent or just two patients, putting en bloc procedures at the lowest end of the GAS risk scale rather than at the highest end as previously assumed.
The difference, according to Troppmann, is modern surgical techniques and post-surgical care.
“We know a lot more now about how to accomplish these operations,” Troppmann said. “We use more of the donor’s blood vessels and have refined immunosuppressive treatments to reduce graft rejection. These changes have improved the long-term health of transplanted organs and attached blood vessels.”
The researchers also attribute the lower-than-expected risk to a prior lack of data. Many transplant centers don’t perform the en bloc procedure owing to its complexity.
UC Davis surgeons, however, have the greatest amount of experience in the nation with deceased donor transplants of all kinds, including en bloc grafts, providing a substantial body of clinical experience for accurate evaluation. The renal transplant team works collaboratively with UC Davis radiologists, whose leadership in cutting-edge imaging techniques allows for accurate, noninvasive evaluations of transplant patients.
“By publishing updated outcomes based on adequate volume, we hope more centers will be encouraged to perform en bloc procedures and help reduce the number of people on kidney transplant wait lists,” Fananapazir said.
Additional study authors (all from UC Davis) were Christopher Bent, Gary Tse, Michael Corwin, Catherine Vu, Chandrasekar Santhanakrishnan and Richard Perez. The study received no external funding.
A copy of “Graft Arterial Stenosis in Kidney En Bloc Grafts from Very Small Pediatric Donors: Incidence, Timing and Role of Ultrasound in Screening” is available online.
More information about UC Davis Health System, including its radiology department and transplant center, is at http://healthsystem.ucdavis.edu.