When is it reasonable to split pediatric en bloc kidneys for transplantation into two adults?

Traditionally, kidneys from donors ≥60 years old and pediatric kidneys are considered marginal organs for transplantation. Pediatric donor kidneys are underutilized for transplantation into adult recipients due to concern for poor outcomes.

Using data from the Organ Procurement and Transplant Network, we analyzed patterns of pediatric kidney use (single vs en bloc) in the United States from 1987 to 2007. Using the Cox proportional hazards model, graft outcomes of pediatric donor kidneys transplanted as single vs en bloc grafts from different donor weight groups were compared with renal transplantation from donors ≥60 years old in an attempt to define a pediatric donor weight at which kidneys can be justifiably split to expand the donor pool.

Compared with older donor kidneys, graft failure risk of pediatric single kidneys was consistently lower when the donor weight exceeded 10 kg. On the other hand, graft survival benefit for pediatric en bloc kidneys was evident starting at donor weight ≤10 kg in comparison to older donor kidneys. Pediatric en bloc kidneys performed consistently better than pediatric single kidneys for all donor weight groups.

Splitting of pediatric donor en bloc kidneys for transplantation into 2 adults when the donor weight exceeds 10 kg was associated with acceptable graft outcomes. This practice, along with increased use of small pediatric donor kidneys, may help to alleviate the waiting list burden in renal transplantation.