Encouraging outcomes of using a small-donor single graft in pediatric kidney transplantation

BACKGROUND

The use of small pediatric kidneys as single grafts for transplantation is controversial, due to the potential risk for graft thrombosis and insufficient nephron mass.

METHODS

Aiming to test the benefits of transplanting these kidneys, 375 children who underwent kidney transplantation in a single center were evaluated: 49 (13.1%) received a single graft from a small pediatric donor (≤ 15 kg, SPD group), 244 (65.1%) from a bigger pediatric donor (> 15 kg, BPD group), and 82 (21.9%) from adult living donors (group ALD).

RESULTS

Groups had similar baseline main characteristics. After 5 years of follow-up, children from the SPD group were comparable to children from BPD and ALD in patient survival (94%, 96%, and 98%, respectively, p = 0.423); graft survival (89%, 88%, and 93%, respectively, p = 0.426); the frequency of acute rejection (p = 0.998); the incidence of post-transplant lymphoproliferative disease (p = 0.671); the odds ratio for severely increased proteinuria (p = 0.357); the rates of vascular thrombosis (p = 0.846); and the necessity for post-transplant surgical intervention prior to discharge (p = 0.905). The longitudinal evolution of eGFR was not uniform among groups. The three groups presented a decrease in eGFR, but the slope of the curve was steeper in ALD children. At 5 years, the eGFR of the ALD group was 10 ml/min/1.73m² inferior to the others. At that time, the eGFR from the SPD group was statistically similar to the BPD group (p = 0.952).

CONCLUSION

In a specialized transplant center, the use of a single small pediatric donor kidney for transplantation is as successful as bigger pediatric or adult living donors, after 5 years of follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

APOL1 in an ethnically diverse pediatric population with nephrotic syndrome: implications in focal segmental glomerulosclerosis and other diagnoses

BACKGROUND

APOL1 high-risk genotypes (HRG) are associated with increased risk of kidney disease in individuals of African ancestry. We analyzed the effects of APOL1 risk variants on an ethnically diverse Brazilian pediatric nephrotic syndrome (NS) cohort.

METHODS

Multicenter study including 318 NS patients, categorized as progressors to advanced CKD [estimated glomerular filtration rate (eGFR)] < 30 mL/min/1.73 m²] and slow/non-progressors (eGFR > 30 mL/min/1.73 m² through the study). We employed Cox regression with progression time as the outcome and APOL1 genotype as the independent variable. We tested this association in the entire cohort and three subgroups; (1) focal segmental glomerulosclerosis (FSGS), (2) steroid-resistant NS (SRNS), and (3) those who underwent kidney biopsy.

RESULTS

Nineteen patients (6%) had an HRG. Of these, 47% were self-reported White. Patients with HRG manifested NS at older ages and presented higher frequencies of FSGS and SRNS. HRG patients progressed to advanced CKD more often than low-risk-genotype (LRG) children in the whole NS cohort (p = 0.001) and the three subgroups. In SRNS and biopsied patients, a single risk variant was associated with trends of higher CKD progression risk.

CONCLUSIONS

Novel discoveries include a substantial prevalence of HRG among patients self-reported White, worse kidney outcomes in HRG versus LRG children in the FSGS subgroup, and a trend of higher CKD progression risk associated with a single risk variant in the SRNS cohort. These findings suggest APOL1-associated NS extends beyond patients self-reported non-White, the HRG effect is independent of FSGS, and a single risk variant may have a detrimental impact in children with NS.

Strategy to Enable and Accelerate Kidney Transplant in Small Children and Results of the First 130 Transplants in Children ≤15 kg in a Single Center

BACKGROUND

Proper care of young children in need of kidney transplant (KT) requires many skilled professionals and an expensive hospital structure. Small children have lesser access to KT.

METHODS

We describe a strategy performed in Brazil to enable and accelerate KT in children ≤15 kg based on the establishment of one specialized transplant center, focused on small children, and cooperating with distant centers throughout the country. Actions on 3 fronts were implemented: (a) providing excellent medical assistance, (b) coordinating educational activities to disseminate expertise and establish a professional network, and (c) fostering research to promote scientific knowledge. We presented the number and outcomes of small children KT as a result of this strategy.

RESULTS

Three hundred forty-six pediatric KTs were performed in the specialized center from 2009 to 2017, being 130 in children ≤15 kg (38%, being 41 children ≤10 kg) and 216 in >15 kg (62%). Patient survival after 1 and 5 years of the transplant was 97% and 95% in the "small children" group, whereas, in the "heavier children" group, it was 99% and 96% (P = 0.923). Regarding graft survival, we observed in the "small children" group, 91% and 87%, whereas in the "heavier children" group, 94% and 87% (P = 0.873). These results are comparable to the literature data. Groups were similar in the incidence of reoperation, vascular thrombosis, posttransplant lymphoproliferative disease, and estimated glomerular filtration rate.

CONCLUSIONS

The strategy allowed an improvement in the number of KT in small children with excellent results. We believe this experience may be useful in other locations.

Collaborative Brazilian pediatric renal transplant registry (CoBrazPed-RTx): A report from 2004 to 2018

The Brazilian collaborative registry for pediatric renal transplantation began in 2004 as a multicenter initiative aimed at analyzing, reporting, and disseminating the results of pediatric renal transplantation in Brazil. Data from all pediatric renal transplants performed from January 2004 to May 2018 at the 13 participating centers were analyzed. A total of 2744 pediatric renal transplants were performed in the thirteen participating centers. The median age at transplantation was 12.2 years, with the majority being male recipients (56%). The main underlying diseases were CAKUT (40.5%) and glomerulopathy (28%). 1981 (72%) of the grafts were from deceased donors (DD). Graft survival at one year (censored by death) was 94% in the live donor group (LD) and 91% in the DD group (log-rank test P < 0.01). The patient's survival at one and 5 years was 97% and 95% for the LD group and 96% and 93% for the DD group (log-rank test P = 0.02). The graft loss rate was 19% (n = 517), more frequently caused by vascular thrombosis (n = 102) and chronic graft nephropathy (n = 90). DD recipients had 1.6 (1.0-2.2) times greater chance of death and 1.5 (1.2-1.8) times greater chance of graft loss compared to LD recipients. The mortality rate was 5.4% (n = 148), mainly due to infection (n = 69) and cardiovascular disease (n = 28). The results of this collaborative pediatric renal transplant record are comparable to other international registries, although we still have a high infection rate as a cause of death.

Cost analysis of substitutive renal therapies in children

OBJECTIVE

End-stage renal disease is a health problem that consumes public and private resources. This study aimed to identify the cost of hemodialysis (either daily or conventional hemodialysis) and transplantation in children and adolescents.

METHODS

This was a retrospective cohort of pediatric patients with End-stage renal disease who underwent hemodialysis followed by kidney transplant. All costs incurred in the treatment were collected and the monthly total cost was calculated per patient and for each renal therapy. Subsequently, a dynamic panel data model was estimated.

RESULTS

The study included 30 children who underwent hemodialysis (16 conventional/14 daily hemodialysis) followed by renal transplantation. The mean monthly outlay for hemodialysis was USD 3500 and USD 1900 for transplant. Hemodialysis costs added up to over USD 87,000 in 40 months for conventional dialysis patients and USD 131,000 in 50 months for daily dialysis patients. In turn, transplant costs in 50 months reached USD 48,000 and USD 70,000, for conventional and daily dialysis patients, respectively. For conventional dialysis patients, transplant is less costly when therapy exceeds 16 months, whereas for daily dialysis patients, the threshold is around 13 months.

CONCLUSION

Transplantation is less expensive than dialysis in children, and the estimated thresholds indicate that renal transplant should be the preferred treatment for pediatric patients.

Pediatric Chronic Dialysis in Brazil: Epidemiology and Regional Inequalities

INTRODUCTION

There are few reports in the literature estimating the epidemiologic characteristics of pediatric chronic dialysis. These patients have impaired physical growth, high number of comorbidities and great need for continuous attention of specialized services with high demand for complex and costly procedures.

OBJECTIVE

The aim of this study was to estimate the incidence and prevalence rates and describe the characteristics of children and adolescents undergoing chronic dialysis treatment in a Brazilian demographic health survey.

MATERIALS AND METHODS

A cross-sectional study was performed in a representative sample of dialysis centers (nc = 239) that was established from the 2011 Brazilian Nephrology Society Census (Nc = 708). We collected data encompassing the five Brazilian macro-regions. We analyzed the data from all patients under 19 years of age. The sample population consisted of 643 children and adolescents who were on chronic dialysis program anytime in 2012. Data collection was carried out in the dialysis services by means of patients' records reviews and personal interviews with the centers' leaders.

RESULTS

We estimated that there were a total of 1,283 pediatric patients on chronic dialysis treatment in Brazil, resulting in a prevalence of 20.0 cases per million age-related population (pmarp) (95% CI: 14.8-25.3) and an incidence of 6.6 cases pmarp in 2012 (95% CI: 4.8-8.4). The South region had the highest prevalence and incidence rates of patients under dialysis therapy, 27.7 (95% CI: 7.3-48.1) and 11.0 (95% CI: 2.8-19.3) cases pmarp, respectively; the lowest prevalence and incidence rates were found in the North-Midwest region, 13.8 (95% CI: 6.2-21.4), and in the Northeast region, 3.8 (95% CI: 1.4-6.3) cases pmarp, respectively.

CONCLUSION

Brazil has an overall low prevalence of children on chronic dialysis treatment, figuring near the rates from others countries with same socioeconomic profile. There are substantial differences among regions related to pediatric chronic dialysis treatment. Joint strategies aiming to reduce inequities and improving access to treatment and adequacy of services across the Brazilian regions are necessary to provide an appropriate care setting for this population group.

Vascular anastomosis for paediatric renal transplantation and new strategy in low-weight children

The technical aspects of RT in low-weight children should be specific, particularly with regard to VA. This retrospective study assesses the main VA options in paediatric RTs and proposes a new strategy for renal artery trajectory when using the Ao and the right iVC. The sample included 81 patients and was categorized into a group of children weighing <16 kg and the other group of children weighing 16 kg or more. The smaller children received the graft predominantly on the Ao and iVC (63%); however, the VA options varied in children weighing more than 16 kg, with anastomoses predominantly to the common iliac vessels (46%). In the first group, when the Ao was the selected vessel for anastomosis on the right side, the trajectory adopted for the transplanted kidney artery was posterior to the iVC. This strategy may reduce the risk of compression of the iVC by the renal artery of the donor kidney and may reconstitute the normal anatomy of the renal artery. Moreover, it did not represent a risk factor for graft loss in this sample.

Does graft mass impact on pediatric kidney transplant outcomes?

BACKGROUND

The aim of this study is to assess the evolution of renal size and function in pediatric transplant patients according to the graft mass/recipient size ratio.

METHODS

Fifty pediatric renal transplant recipients were followed over 2 years. Grafts were weighed, and three different graft mass/m(2) ratios were determined: (1) low graft mass (58 g/m(2), range 31-57 g/m(2)), (2) median (142 g/m(2), range 59-141 g/m(2)) and high (267 g/m(2), range 143-353 g/m(2)). Patients underwent repeated ultrasound Doppler scans and repeated measurements of estimated glomerular filtration rate (eGFR; 1 week and 1, 6, 12 and 24 months), urinary retinol-binding protein (RBP) and proteinuria (1 week and 6, 12 and 24 months).

RESULTS

The volume of renal tissue increased by 12 ± 5.6 cm(3) at 24 months (p = 0.035) in the low graft mass and decreased by -14 ± 7 cm(3) (p = 0.046) in the high graft mass. The eGFR increased when either low (30 ± 5 ml/min/1.73 m(2), p < 0.001) or median (19 ± 4 ml/min/1.73 m(2), p < 0.001) graft mass was transplanted but remained stable when high graft mass was transplanted. The resistive index (RI) presented a significant decrease throughout early follow-up in the transplants involving low and median graft mass, whereas a slight rise was observed in those involving high graft mass. A significant difference was apparent 6 months post-transplant. Transplants of low and median graft mass were associated with an initial higher urinary RBP. No significant differences in proteinuria were detected.

CONCLUSIONS

Small kidneys undergo increases in volume and function without escalation of either proteinuria or urinary RBP, characterizing an adequate adaptation to the recipient. Children receiving larger kidneys present a reduction in volume, stable GFR and higher RI at 6 months.

Estimated prevalence of childhood end-stage renal disease in the state of São Paulo

OBJECTIVE

To estimate the prevalence of pediatric end-stage renal disease and evaluate demographics and renal disease characteristics in state of São Paulo over the year 2008.

METHODS

Observational, descriptive, and cross-sectional study based on a population sample with subjects < 18 years. The data collecting assumed three forms: 1. A questionnaire for dialysis units; 2. Search in the Transplant Center to determine the number and characteristics of patients who had been in a transplant waiting list over the study period; 3. Search in the database of patients registered at the Latin American Collaborative Registry of Pediatric Kidney Transplantation.

RESULTS

Data from 301 patients aged 9.0 ± 5.8, including 140 girls (46.5%), resulting in an estimate prevalence of 23.4 cases per million age-related population (pmarp). The age group most frequently found was 10 to 15 years (32.2%), and urinary tract malformation was the most usual known etiology (24.9%). Most children underwent kidney transplantation (62.1%) and among subjects on dialysis, hemodialysis was predominant (71.2%). The Sistema Único de Saúde - Unified National Health System - (SUS) provided the financial support for treatments.

CONCLUSION

The prevalence of 23.4 cases pmarp found by the authors is lower than that reported in Western world. We believe data were underestimated in the present study, as few dialysis units returned the completed questionnaire. This potential bias does not invalidate the exploratory character of results. Further mechanisms for retrospective and earlier data collecting on pediatric chronic renal disease (CRD) are needed so that the burden of this serious health condition can be appropriately sized up.

Assessment of Factors Determining Graft Size in Transplant of Cadaver Kidneys from Child Donors

BACKGROUND

Kidneys from child donors are very efficient at adapting to the recipient organism. This research aims to verify the size of kidney grafts from pediatric donors after transplant and to identify factors responsible for the size attained by these kidneys. Moreover, it aims to seek relationships between size and function of the transplanted pediatric kidney.

METHODS

Seventy-seven renal transplants performed at least 6 months earlier, with cadaver donor 15 years old or younger, had ultrasound measurements of the graft and renal function assessment. Potential factors for graft volume were analyzed using bivariate analysis, followed by multiple linear regression.

RESULTS

After a follow up of 4.2+/-3.3 years posttransplant, the grafts presented the following range of measures: length 10.61+/-1.13 cm, width 4.67+/-0.84 cm, and depth 4.76+/-0.99 cm. Graft volumes were 126.62+/-47.76 cm. Bivariate analysis showed that (1) age of both donor and recipient at transplantation; (2) sex of recipient; (3) occurrence of acute rejection episodes were statistically significant. After multivariate analysis, age and sex of recipients were the only significant factors influencing graft volume; child kidneys reached greater volumes when transplanted into adult and male individuals. Larger volume kidneys presented significantly more proteinuria. No difference was evident with regard to creatinine clearance values or urinary retinol binding protein among kidneys of differing sizes.

CONCLUSIONS

The size of the recipient (age and sex) is the main factor responsible for volumes achieved by kidneys from pediatric donors. The volume attained by these kidneys demonstrated no relationship with glomerular or tubular function of the organ.

Renal complications of sickle cell disease: managing for optimal outcomes

A broad spectrum of renal changes is observed in patients with sickle cell anemia, and ideal therapeutic measures for the management of these alterations are still being studied. Affected patients have deficient urinary concentration and potassium excretion. Perhaps owing to a compensatory mechanism, the proximal tubules are in a condition of "hyperfunction", with increased sodium and phosphorus reabsorption and greater creatinine and uric acid secretion. Mild tubular acidosis may be present. No treatment has been reported for these tubular changes, except for care in the maintenance of hydration. The use of anti-inflammatory drugs is being studied in order to inhibit the prostaglandins involved in the process. Increased renal blood flow, glomerular filtration rate, and filtration fraction are frequent findings. Hematuria commonly occurs as a consequence of red blood cell sickling in the renal medulla, papillary necrosis, or even renal medullary carcinoma. Measures such as increased fluid ingestion, urine alkalinization and, if necessary, administration of epsilon-aminocaproic acid and certain invasive procedures have been proposed to treat hematuria. Nephropathy in patients with sickle cell anemia can be manifested by proteinuria and, more rarely, nephrotic syndrome. Drugs such as prednisone and cyclophosphamide are ineffective for the treatment of patients with nephrotic syndrome. Angiotensin converting enzyme inhibitors decrease proteinuria, but their long-term effect in preventing the progression of glomerular disease has not been established. Chronic renal failure, although infrequent, may be one of the manifestations of this disease. Hemodialysis and transplantation are satisfactory therapeutic options for patients with end-stage renal disease.