Comparison of Renal Growth, Proteinuria and Graft Survival between Recipients of Pediatric and Adult Cadaveric Kidney Transplants

BACKGROUND The shortage of cadaveric kidney donors has prompted transplant teams to expanding the donor selection criteria. The usage of pediatric cadaveric kidneys is one of those expanded criteria. But the main concern is the probability of hyperfiltration syndrome due to small renal mass of pediatric donors. OBJECTIVE To compare the graft and patient survivals, post-transplantation complications, rate and severity of proteinuria secondary to hyperfiltration injury and the kidney growth of recipients who underwent transplantation from adult (group 1) and pediatric deceased donors (group 2). METHODS In this historical cohort study, each group contains 36 patients. Outcome measures included patient and graft survivals, quality of graft function as assessed by serum creatinine (SCr) and estimated GFR (eGFR), surgical complications, proteinuria that was detected by routine urinalysis and then confirmed by a 24-h urine protein >150 mg, blood pressure, and kidney length and volume measured by early and follow-up ultrasonography. RESULTS The mean donor age in groups 1 and 2 was 36 and 6.5 years, respectively. 9 (25%) kidneys taken from pediatric donors (group 2) were offered en-bloc. The mean follow-up was 28 month. The two groups were not significantly different in terms of the incidence of DGF, rate of acute rejection, 1-year graft survival, SCr and eGFR levels, rates of surgical complications requiring surgical interventions, development of proteinuria, and rate of post-transplantation rise in blood pressure. The mean±SD kidney length within 24 hours of transplantation was significantly higher in group 1 compared to group 2 recipients (112±14 vs. 75±12 mm; p=0.001), but the rate of increase in kidney length in group 2 was significantly higher than that in group 1 recipients (43±4 vs. 10±2 mm; p=0.002) during the follow-up period. 80% of the increase in the kidney size was observed during the first 12 months of surgery; another 20% happened between 12 and 18 months. CONCLUSION We found that obligatory and compensatory growth of pediatric kidney donors can overcome the concern of hyperfiltration syndrome and that the outcome is the same as adult donors.