Background: We have earlier shown an increase in the size and excellent graft function of paediatric kidneys transplanted to adults up to 1 year following transplantation. This study was performed to assess the long-term outcome of these transplants.
Methods: From a primary cohort of 19 adults, receiving a first kidney transplant from a paediatric donor <10 years of age, 16 patients were available for a complete long-term follow-up, 5-9 years post-transplant. Of these, eight patients were transplanted with a donor of <5 years. All medical files and registry data of the cohort, from the time of transplantation to the follow-up time point, were recalled and events were registered. The patients' general condition, body weight, blood and urine tests, blood pressure (BP), use of antihypertensive agents and GFR were recorded. To explore the temporal increment in the size of paediatric donor kidneys transplanted to adults, the maximal cranio-caudal length of the kidneys from the time of transplantation to follow-up was established by ultrasound. Volumes (length x width x thickness x pi/6) of en bloc kidneys versus single paediatric kidneys and adult-to-adult transplants were compared.
Results: Long-term (7 years, median) patient and graft survival was 95% and 89%, respectively. Mean serum creatinine was 85 micromol/l (range, 32-131). The mean estimated GFR was 84 ml/min/1.73 m(2). The mean BP was 134/79 mmHg (range, 120-185/70-90). The number of antihypertensive agents used was not statistically different from the number used at 1 year post-transplant. None of the patients had significant proteinuria as a sign of hyperfiltration injury of the graft. There were no statistically significant increases in the maximal cranio-caudal length of the transplanted kidney(s) from 1 year post-transplant to follow-up; however, the en bloc kidneys tended to be larger than single paediatric grafts (240 ml and 204 ml) and adult-to-adult grafts (170 ml).
Conclusion: Paediatric kidneys transplanted to adults should be considered as excellent for transplantation on a long-term basis.