Kidney Volume Growth and Kidney Function of En Bloc Pediatric Kidney Transplants: A Case Series

RATIONALE & OBJECTIVE: Kidney transplant is a mainstay of kidney replacement therapy. Given a continued shortage of organs, pediatric en bloc kidney transplants may have substantial utility. We present our long-term experience with en bloc transplants from donors aged 3 to 60 months, including changes in kidney function and kidney volume over time as well as biopsy findings. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Medical records from a single academic medical center were reviewed. Aggregate serial volumes of 22 en bloc kidney allografts from 2010 to 2017 were assessed at the time of transplant and during follow-up. Estimated glomerular filtration rates (eGFR) were described at 3 months after transplant (baseline) as well as over the ensuing 3 years. Interstitial fibrosis, a finding determined by histopathologic review, which results from an accumulation of collagen that is produced from mediators produced from complex interaction of multiple inflammatory cells, was assessed on 20 protocol biopsies obtained from 6 patients, of which 4 patients had 4 biopsies and 2 patients had 1 biopsy. RESULTS: Kidney volume was obtained from 51 ultrasound studies performed up to 74 months after transplant. Kidney volume generally increased and eGFR rose over time after the transplant, with 23% patients achieving an eGFR of >75 mL/min/1.73 m(2) at 3 months posttransplant. The remainder achieved an eGFR >75 mL/min/1.73 m(2) over the ensuing 3 years. Interstitial fibrosis noted on biopsies appeared to foreshadow an eventual reduction in kidney volume. LIMITATIONS: Retrospective study, possible selection bias, single-center experience. CONCLUSIONS: The kidney en bloc allografts increased in size after transplantation, with associated improved kidney function. Chronic damage to the graft, from interstitial fibrosis and tubular atrophy, resulted in long-term reduction in kidney volume.