Pediatric en bloc kidney transplantation to adult recipients: more than suboptimal?

Background. To optimize available organs, kidneys from young donors traditionally beleived to be suboptimal are transplanted to adults. The purpose of this study is to compare graft survival (GS) of en bloc kidney (EBK) from young pediatric donors to other deceased donor transplants in adult recipients. Methods. We analyzed United Network of Organ Sharing/STAR data on primary deceased donor kidney transplants to adult recipients (1988-2006). EBK (age younger than 5 years, n = 1696) was compared with solitary pediatric (SP; age younger than 5 years) kidneys (n = 1502), and matched standard adult donors (age 18-59 years, n = 9594) and expanded criteria donor (ECD; n = 6396). The adjusted GS was obtained using Cox proportional hazard model and hazard ratios were calculated. Results. EBK had lowest acute rejection rates (6.0%) but similar to standard adult transplants (6.3%), and lower than SP and ECD (9.0% and 8.2%; P<0.0001). Delayed graft function rates were lowest in EBK (17.9%), highest in ECD (34.8%; P<0.0001), and similar among SP and standard adult transplants (24.4% and 24.2%). The estimated glomerular filtration rate (eGFR) was best in EBK and worst in ECD (P<0.0001). The eGFR of EBK and SP transplants continuously improved but the eGFR of standard adult and ECD declined. Graft loss was higher in EBK and SP transplants than adult donor transplants during the first 6 months. Despite the highest thrombosis rates in EBK (5.0%) (SP, 3.3%; standard adult, 1.8%; ECD, 2.0%, P<0.0001), GS of EBK became similar to standard adult donor transplants by 5 years and best at 10 years posttransplant (64.0%) and worst in ECD (39.6%; P<0.0001). Conclusion. EBK had the best long-term outcomes among deceased donor transplants and offer unique options for adult kidney transplant recipients.