Adult-sized Renal Transplantation in Small Pediatric Recipients Achieves Long-term Outcomes Comparable to Size-matched Transplantation

Abstract

Background: The use of adult-sized kidneys seems applicable to low-weight children where size-matched donors are scarce. The aim of this study is to assess the impact of donor-recipient size mismatch on long-term renal graft and patient survival in small recipients, in order to optimize graft allocation. Methods: Between 1999-2010, 46 renal transplants were performed in recipients glomerular filtration rate (GFR), proteinuria, rejection episodes, graft and patient survival were analyzed and compared between groups at the time of transplantation (T0), at one (T1), two (T2), five years (T5), and at the end of the study (TF). Results: The mean renal size (longitudinal length in cm) was significantly different at T0, T1 and T2 between both groups (pT0<0.01; pT1<0.01; pT2<0.01), showing a significant increase in group B during the follow up, being similar to group A at T5 and TF (pT5=0.16; pTF=0.92). The mean GFR (ml/min/1.73 m2) was significantly higher at T0 in group A, compared to B (GFRA=148 ± 47; GFRB=111 ± 33; pT0=0.01); at T1 it decreased in A and increased in B (GFRA=127 ± 38; GFRB=121 ± 31; pT1=0.66), with similar values in both groups at T2, T5 y TF (pT2=0.83; pT5=0.15; pTF=0.90). During follow-up (8.6 ± 4.1 yrs) 9 grafts were lost, 2 in A and 7 in B. Two patients died in group B. No significant differences were observed in graft and patient survival at 5 and 10 years (p=0.66; p=0.19) neither proteinuria nor rejection. Conclusion: Adult-sized grafts in small recipients showed a reduction of the function, but remained a stable size. These grafts can be safely transplanted with comparable outcomes to size-matched kidneys.