Long-Term Clinical Outcome Of Paediatric Kidneys Transplanted To Adults
Long-Term Clinical Outcome Of Paediatric Kidneys Transplanted To Adults
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 × width × thickness × π/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 μmol/l (range, 32–131). The mean estimated GFR was 84 ml/min/1.73 m. 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.
Although live donation in kidney transplantation is steadily increasing, the uraemic population awaiting a kidney transplant is expanding. There is evidence that paediatric kidneys transplanted into adult recipients have good graft function and satisfactory graft survival. Still, data show that a significant part of paediatric donor kidneys is not used for transplantation and that graft survival, when transplanted to adults, often is inferior compared to adult kidney grafts. Due to the scarcity of donors and a high mortality rate of the dialysis population, it is of uttermost importance to clarify and analyse all aspects for the optimal use of paediatric donor kidneys. In a recent prospective, single-centre study, we have shown that paediatric kidneys transplanted to adults have a substantial potential for growth, improvement of function and excellent graft function (100%) up to 1 year post-transplant. When initial complications are avoided, several authors have suggested that paediatric kidneys may be considered as excellent, rather than marginal, for transplantation to adults. Data regarding long-term function and single or en bloc transplantation of small paediatric kidneys are diverging. In the present study, a complete long-term follow-up of the patients from the mentioned primary study was performed with primary focus on continued growth and graft function.
In the primary study, 19 adults received a kidney from a donor of <10 years of age. The study was prospectively designed. Increment in the size post-transplant and measurements of function were evaluated at 1, 3, 6 and 12 months post-transplant. At 1 year post-transplant, patient and graft survival was 100%, indicating that paediatric kidneys are excellent for transplantation to adult recipients at least up to 1 year following transplantation. At transplantation the patients received standard immunosuppression, which consisted of steroids, cyclosporine and azathioprine for the first 13 recipients enrolled in the study. In the last six patients, basiliximab (n = 3) or mycophenolate mofetil (n = 3) was used instead of azathioprine.
After the first year post-transplant, the patients have been regularly examined by their local nephrologist. Each year, updated reports of all patients have been received and recorded in the Norwegian Nephrology Registry. In the present study, all patients from the primary study were summoned for a complete long-term check-up, 6–9 years post-transplant (median, 7 years). The general condition of the patients, body weight, blood and urine tests, blood pressure (BP), immunosuppression and use of antihypertensive agents were recorded. GFR was estimated based on the updated MDRD study equation, i.e. GFR = 30 849 × (standardized Scr) × (age) × 0.742 (0.742 was replaced by 1.0 if the subject was male), and expressed as ml/min/1.73 m.
To evaluate if paediatric renal transplants increase in size beyond the first year post-transplant, U/S measurement of the cranio-caudal length of the transplanted grafts was repeated and compared with measurement performed at 1 year post-transplant. The same U/S machine was used in the follow-up study as in the primary study (Siemens Acuson SequoiaTM, 4C1 ultrasound transducer). All examinations in the follow-up study were done by one radiologist (A.G.). The maximal cranio-caudal length was measured on a longitudinal scan through the renal hilum. In recipients with two en bloc grafts, the sum of both kidneys was calculated as the graft length. Scans were retrospectively compared to the scans from the primary study (1 year post-transplant) in order to reduce measurement inaccuracies due to different placement of the electronic callipers.
Kidney transplants from donors <5 years, and particularly en bloc transplants, are of special interest. The cohort is too small to give valid answers to what extent en bloc kidneys increase in size. However, to give a hint, volumes (length × width × thickness × π/6) of en bloc kidneys and single transplanted kidneys at 7 years post-transplant were compared. To assess whether en bloc kidneys reach the size of an adult kidney volume, measures of en bloc kidneys were compared with nine functioning adult-to-adult kidney grafts 5–10 years after transplantation. 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.
Statistical level of significance was set to P < 0.05. Data in the figure are expressed as mean and 95% confidence interval (CI) and in the table as mean and range. For comparisons of 1-year data and long-term data, two-tailed repeated measures analyses of variance were performed. To assess the association between the maximal cranio-caudal length of the kidneys and BMI, a linear regression analysis was performed. SPSS (version 13, SPSS Inc., Chicago, IL, USA) was used for the statistical calculations.
Abstract and Introduction
Abstract
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 × width × thickness × π/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 μmol/l (range, 32–131). The mean estimated GFR was 84 ml/min/1.73 m. 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.
Introduction
Although live donation in kidney transplantation is steadily increasing, the uraemic population awaiting a kidney transplant is expanding. There is evidence that paediatric kidneys transplanted into adult recipients have good graft function and satisfactory graft survival. Still, data show that a significant part of paediatric donor kidneys is not used for transplantation and that graft survival, when transplanted to adults, often is inferior compared to adult kidney grafts. Due to the scarcity of donors and a high mortality rate of the dialysis population, it is of uttermost importance to clarify and analyse all aspects for the optimal use of paediatric donor kidneys. In a recent prospective, single-centre study, we have shown that paediatric kidneys transplanted to adults have a substantial potential for growth, improvement of function and excellent graft function (100%) up to 1 year post-transplant. When initial complications are avoided, several authors have suggested that paediatric kidneys may be considered as excellent, rather than marginal, for transplantation to adults. Data regarding long-term function and single or en bloc transplantation of small paediatric kidneys are diverging. In the present study, a complete long-term follow-up of the patients from the mentioned primary study was performed with primary focus on continued growth and graft function.
Subjects and Methods
In the primary study, 19 adults received a kidney from a donor of <10 years of age. The study was prospectively designed. Increment in the size post-transplant and measurements of function were evaluated at 1, 3, 6 and 12 months post-transplant. At 1 year post-transplant, patient and graft survival was 100%, indicating that paediatric kidneys are excellent for transplantation to adult recipients at least up to 1 year following transplantation. At transplantation the patients received standard immunosuppression, which consisted of steroids, cyclosporine and azathioprine for the first 13 recipients enrolled in the study. In the last six patients, basiliximab (n = 3) or mycophenolate mofetil (n = 3) was used instead of azathioprine.
After the first year post-transplant, the patients have been regularly examined by their local nephrologist. Each year, updated reports of all patients have been received and recorded in the Norwegian Nephrology Registry. In the present study, all patients from the primary study were summoned for a complete long-term check-up, 6–9 years post-transplant (median, 7 years). The general condition of the patients, body weight, blood and urine tests, blood pressure (BP), immunosuppression and use of antihypertensive agents were recorded. GFR was estimated based on the updated MDRD study equation, i.e. GFR = 30 849 × (standardized Scr) × (age) × 0.742 (0.742 was replaced by 1.0 if the subject was male), and expressed as ml/min/1.73 m.
To evaluate if paediatric renal transplants increase in size beyond the first year post-transplant, U/S measurement of the cranio-caudal length of the transplanted grafts was repeated and compared with measurement performed at 1 year post-transplant. The same U/S machine was used in the follow-up study as in the primary study (Siemens Acuson SequoiaTM, 4C1 ultrasound transducer). All examinations in the follow-up study were done by one radiologist (A.G.). The maximal cranio-caudal length was measured on a longitudinal scan through the renal hilum. In recipients with two en bloc grafts, the sum of both kidneys was calculated as the graft length. Scans were retrospectively compared to the scans from the primary study (1 year post-transplant) in order to reduce measurement inaccuracies due to different placement of the electronic callipers.
Kidney transplants from donors <5 years, and particularly en bloc transplants, are of special interest. The cohort is too small to give valid answers to what extent en bloc kidneys increase in size. However, to give a hint, volumes (length × width × thickness × π/6) of en bloc kidneys and single transplanted kidneys at 7 years post-transplant were compared. To assess whether en bloc kidneys reach the size of an adult kidney volume, measures of en bloc kidneys were compared with nine functioning adult-to-adult kidney grafts 5–10 years after transplantation. 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.
Statistical Methods
Statistical level of significance was set to P < 0.05. Data in the figure are expressed as mean and 95% confidence interval (CI) and in the table as mean and range. For comparisons of 1-year data and long-term data, two-tailed repeated measures analyses of variance were performed. To assess the association between the maximal cranio-caudal length of the kidneys and BMI, a linear regression analysis was performed. SPSS (version 13, SPSS Inc., Chicago, IL, USA) was used for the statistical calculations.
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