Pediatric renal transplantation: a single center experience over 14 years

The impact of multiple donor renal arteries on perioperative complications and allograft survival in paediatric renal transplantation

BACKGROUND

The impact of using allografts with multiple renal arteries in paediatric kidney transplantation has not been clearly established. The aim of this study was to determine whether kidney grafts with multiple arteries pose any adverse effects upon perioperative surgical outcomes, and graft survival up to 12 months post-transplant.

OBJECTIVE

The objective of this study was to perform a comparative analysis of a minimum of 12-month graft survival and transplant renal function in paediatric renal transplant recipients receiving single versus multiple donor arteries, and to assess perioperative and early post-operative surgical outcomes.

STUDY DESIGN

A retrospective divisional chart review of 379 transplants performed (2000-2018), of which 90 (23.7%) contained multiple donor arteries. The number of arteries of the graft, donor type, vascular reconstruction technique, occurrence of urological and vascular complications, estimated GFR and graft survival up to 12 months post-transplantation, graft loss and mortality were analysed. Comparisons in baseline characteristics and outcome measures were made between both groups.

RESULTS

No significant differences were found in age (p = 0.42), BMI (p = 0.39), estimated intraoperative blood loss (p = 0.14), overall (p = 0.63) or warm ischaemic time (p = 0.37). 51.3% patients with multiple donor arteries underwent an ex vivo reconstruction. There were no differences in the site of arterial anastomosis (aorta, external iliac, internal iliac), or anastomotic type (end-side; end-end). Whilst there was a significantly higher post-operative lymphocoele rate in the multiple vessel cohort (p = 0.024), there was no increase in post-transplant urine leaks, rejection episodes, graft loss (1.1% multiple vs 2.1% single), perioperative complications (p = 0.68), or estimated GFR at 1 month (p = 0.9) or at 1 year (p = 0.67).

DISCUSSION

We demonstrated in this study that there was no significant difference in postoperative complications up to 3 months, eGFR and renal function up to 1 year, and graft survival up to 4 years post transplantation irrespective of allograft type or reconstruction technique. There was however, a higher rate of lymphocoeles in the multiple artery cohort. The results seen here broadly mirror trends seen in adult studies, however, there is little data available from paediatric series.

CONCLUSION

Our study demonstrates that multiple renal artery allografts - previously been considered to carry a high complication risk - can be safely used for paediatric renal transplantation with equivalent perioperative complications and graft outcomes to single artery allografts.

Kidney transplant in pediatric patients with severe bladder pathology

The aim of the current study was to compare results in pediatric renal transplantation of patients with and without SBP. Between 2001 and 2013, a total of 168 kidney transplants were performed at our center. A retrospective analysis was performed and recipients were divided into two groups: NB and SBP. Incidence of surgical complications after procedure, and graft and patient survival were evaluated. A total of 155 recipients (92%) with complete data were analyzed, and 13 recipients that had had previous bladder surgeries were excluded (11 with VUR surgery and two with previous kidney transplants), of the 155 recipients: 123 (79%) patients had NB, and 32 (21%) patients had SBP, with a median follow-up of 60 (1-137) and 52 (1-144) months, respectively. Among post-transplant complications, UTI (68.8% vs. 23%, p < 0.0001) and symptomatic VUR to the graft (40.6% vs. 7.3%, p < 0.0001) were significantly higher in the SBP group. There was no significant difference in overall graft and patient survival between groups. Renal transplantation is safe in pediatric recipients with SBP; however, urologic complications such as UTI and VUR were significantly higher in this group. Graft and patient survival was similar in SBP and NB groups.

The effect of chemokine receptor gene polymorphisms (CCR2V64I, CCR5-59029G>A and CCR5Δ32) on renal allograft survival in Pakistani transplant patients

BACKGROUND

Gene polymorphisms of the chemokine receptors CCR2 and CCR5 (CCR2V64I, CCR5-59029G>A and CCR5Δ32) have been shown to be associated with renal allograft rejection. The aim of this study was to investigate the association of these polymorphisms with allograft rejection among Pakistani transplant patients.

METHOD

A total of 606 renal transplant patients and an equal number of their donors were included in this study. DNA samples were used to amplify polymorphic regions of CCR2V64I, CCR5-59029G>A and CCR5Δ32 by polymerase chain reaction using sequence specific primers. The amplified products of CCRV64I and CCR5-59029G>A were digested with restriction enzymes (BsaB1 and Bsp12861) respectively. The CCR5Δ32 genotypes were determined by sizing the PCR amplicons. The association of these polymorphisms with the biopsy proven rejection and other clinical parameters was evaluated using the statistical software SPSS v.17.

RESULTS

In this study, the G/G genotype of CCR2V64I was associated with a high frequency of allograft rejection (p=0.009; OR=2.14; 95% CI=1.2-3.7). Rejection episode(s) in the GA+AA genotypes were found to be significantly lower as compared to the GG genotype (p=0.009; OR=0.4; 95% CI=0.2-0.8). The Kaplan-Meier curve also indicated a reduced overall allograft survival for patients with the G/G genotype of CCR2V64I (59.2 ± 1.4 weeks, log p=0.008). There was a significant association with rejection by female donors possessing the CCR2 GG genotype (p=0.02; OR=2.6; CI=1.1-6.3) and male donors with the CCR5-59029 GG genotype (p=0.004; OR=1.7; CI=1.03-3.01).

CONCLUSION

This study shows an association of the CCR2V64I (G/G) genotype with renal allograft rejection. However, no such association was found for the CCR5 gene polymorphisms. Therapeutic interventions such as blocking the CCR2 receptor (especially G polymorphism) may yield better survival of renal allograft in this patient group. Further, chemokine receptors may be added to the spectrum of the immunogenetic factors that are known to be associated with renal allograft rejection.

Early steroid withdrawal in pediatric renal transplant: five years of follow-up

This prospective, comparative trial investigated the impact on mean change in height standard deviation score (SDS), acute rejection rate, and renal function of early steroid withdrawal in 96 recipients with 5 years of follow-up. Recipients under basiliximab induction and steroid withdrawal (SW: TAC/MMF; n = 55) were compared with a matched steroid control group (SC: TAC/MMF/STEROID, n = 41). SW received steroids until Day 6, SC decreased to 10 mg/m(2) within 2 months post-transplant. Five years after SW, the longitudinal growth (SDS) gain was 1.4 ± 0.4 vs. 1.1 ± 0.3 for SC group (p < 0.02). Height benefits in prepubertal and pubertal status in both groups were demonstrated in the delta growth trends (mixed model; p < 0.01). Biopsy-proven acute rejection in SW was 11% and 17.5%, SC (p: ns). Mean eGFR (ml/min/1.73 m(2)) at 5 years post-transplant was SW 80.6 ± 27.8 vs. 82.6 ± 25.1 for SC (p: ns). The death-censored graft survival rate at 1 and 5 years was 99 and 90% for SW; 98 and 96% for SC (p = ns). PTLD incidence in SW 3.3 vs. 2.5% in SC (p: ns). Five years post-transplant, early steroid withdrawal showed positive impacts on growth, stable renal function without increased acute rejection risk, and PTLD incidence.

Outcome of renal transplantation in children: a multi-center national report from Iran

The outcome of pediatric renal transplantation was previously reported by a single-center study at the year 2006. Therefore, we aimed to evaluate and report the characteristics and outcome of renal pediatric renal transplantation in a multi-center nationwide study. In this nationwide report, medical records of 907 children (≤18yr) with renal transplantation in eight major pediatric transplant centers of Iran were recorded. These 907 patients received a total of 922 transplants. All children who failed to follow-up were excluded. Rather than baseline characteristics, graft and patient outcomes were considered for survival analysis. For further analysis, they were divided into two groups: patients who had graft survival time more than 10yr (n=91) and the ones with graft survival time of equal or less than 10yr (n=831). Of 922 recipients, 515 (55.8%) were boys and 407 (44.2%) were girls with the mean age of 13.10 (s.d.=3.54) yr. DGF and AR were occurred in 10% and 39.5% of the transplanted children, respectively. Transplantation year, dialyzing status before transplantation, DGF, and AR were significant enough to predict graft survival in cox regression model (overall model: p<0.001). Nowadays, there is a successful live donor pediatric renal transplantation in Iran. Graft survival has improved in our recipients and now the graft survival rates are near to international standards.

Adherence to the immunosuppressive regimen in pediatric kidney transplant recipients: a systematic review

As most prior reviews on NA focus on adult transplant patients, there is a need for a comprehensive overview on adherence to the immunosuppressive regimen in pediatric kidney transplant patients. This systematic review searched for English-language papers (1990-2008) addressing the prevalence of NA to the immunosuppressive regimen, its consequences, determinants, and interventions in pediatric kidney transplant patients (< age 21 yr). We found 36 papers, showing a prevalence of NA (weighted mean) of 31.8% with adolescents being more at risk compared to younger patients. About 44% of all graft losses and 23% of late acute rejection episodes are associated with NA. Most studies investigated socio-economic, condition-related or treatment-related determinants. Only one educational intervention has been tested but yielded inconclusive results. NA to the immunosuppressive regimen is prevalent with serious clinical consequences in pediatric kidney transplant patients, but the economic consequences have not yet been explored. More studies on determinants of NA are needed. The literature currently lacks fully powered RCTs testing adherence-enhancing interventions. The results of this systematic review identify the gaps in the present evidence-based information regarding NA and can be used as a tool to pursue future adherence research in pediatric populations.

Immunosuppressant therapy adherence and graft failure among pediatric renal transplant recipients

The study objective was to determine the association between immunosuppressant therapy (IST) adherence and graft failure among pediatric renal transplant recipients (RTRs) using data reported in the United States Renal Data System (USRDS), which contains Medicare prescription claims. RTRs (<or=18 years) who received their only transplant during 1995-2000, experienced graft survival more than 6 months posttransplant, had 36 months of USRDS data (or had data until graft failure or death), utilized Medicare IST coverage, and were prescribed cyclosporine/tacrolimus were included. IST adherence was measured by medication possession ratio (MPR). Cox proportional hazards analysis was used to assess the relationship between time to graft failure and continuous MPR. MPR quartiles were used to examine MPR as a categorical variable (Quartile 4 = adherent group, Quartiles 1-3 = nonadherent group). Kaplan-Meier estimates of time to graft failure were compared between adherent and nonadherent groups. 877 RTRs met inclusion criteria. Cox proportional hazards modeling suggested that greater adherence was significantly associated with longer time to graft failure (p = 0.009), after adjusting for relevant clinical factors. Kaplan-Meier analysis found a difference between adherent and nonadherent groups in graft survival by time (chi(2)= 5.68, p = 0.017). Interventions promoting adherence should be implemented among pediatric RTRs and parents/guardians to optimize graft survival.

Nineteen-Year Experience of Paediatric Renal Transplantation in Singapore

Introduction: Renal transplantation is the treatment of choice for children with end-stage renal failure (ESRF). The paediatric renal transplant programme in Singapore was initiated in 1989. This study aimed to examine our outcomes over the 19-year period from 1989 to 2007. Materials and Methods: A total of 38 renal transplants were performed at our centre. Another 4 patients with overseas transplants who returned within 3 weeks post-transplant were included. The proportion of living donor (LD) transplants was 61.9%. Structural abnormalities and glomerulopathies were the most common aetiologies comprising 33% each. Median age at transplant was 13.9 years and median waiting time was 2.2 years. LD transplant recipients were younger and had a shorter waiting time than deceased donor (DD) recipients. Results: Overall patient survival rates were 95%, 92%, 86% and 86% at 1, 5, 10 and 15 years, respectively. There were 4 deaths, of which 3 were due to infections. Graft survival rates at 1, 5, 10 and 15 years for LD and DD transplants were 100%, 89.5%, 67.3%, 67.3% and 80.8%, 56.5%, 42.2%, 28.3% respectively, and were significantly higher in LD transplants. The main cause of graft loss was rejection following non-adherence. Multivariate analysis showed male gender, late acute rejections and acute tubular necrosis as predictors of graft failure. There was a high incidence of early bacterial infections (42.9%) and cytomegalovirus disease (16.7%). Conclusion: Our graft survival rates for LD transplants were comparable to North American rates, although our DD transplant rates were slightly worse, probably a reflection of the prevailing transplant policies. Key words: Deceased donor, Living donor, Paediatric transplantation

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Long-term outcome of pediatric renal transplantation: the Norwegian experience in three eras 1970-2006

During the years 1970-2006, 251 renal transplantations were performed in 178 children in Norway. The proportion of LD was 84%. Transplantations were performed preemptively in 52%. Pretransplant dialysis time was median three months. Structural abnormalities and hereditary renal disorders constituted 69% of end-stage renal diseases, 29% were caused by glomerulopathies and other acquired disorders and 2% of unknown cause. Patient survival rates were 94.2, 93.5, and 84.4% at five, 10, and 20 yr, respectively. The most frequent cause of death was infections followed by cardiovascular events. For recipients of living donor grafts (n = 149), survival of first transplant was 82, 68.8, and 45.1% at five, 10, and 20 yr, respectively, and was significantly higher than for recipients of deceased donor organs (n = 29; log rank, p = 0.008). The only significant predictor for better transplant survival when modeled with multiple regression analysis adjusted for pretransplant dialysis, diagnosis, donor age, sex and immunosuppressive era, was the use of LD compared with DD (HR = 2.1, 95% CI [1.1-4.0], p = 0.02). The acute rejection rate declined significantly from 61.5% in 1970-1982 to 14.5% in 2000-2006 (log rank, p = 0.002). It remains to be seen whether the reduction in acute rejection rate and present immunosuppressive therapy will have a positive impact on long-term graft survival in years to come.

Vesicoureteral reflux, reflux nephropathy, and end-stage renal disease

Objective. To review the contribution of vesicoureteral reflux and reflux nephropathy to end-stage renal disease. Data Source. Published research articles and publicly available registries. Results. Vesicoureteral reflux (VUR) is commonly identified in pediatric patients and can be associated with reflux nephropathy (RN), chronic kidney disease (CKD), and rarely end-stage renal disease (ESRD). Patients with reduced GFR, bilateral disease, grade V VUR, proteinuria, and hypertension are more likely to progress to CKD and ESRD. Because progression to ESRD is rare in VUR and often requires many decades to develop, there are limited prospective, randomized, controlled trials available to direct therapy to prevent progression to ESRD. Conclusions. Identification of patients with increased risk of progression to CKD and ESRD should be the goal of clinical, biochemical, and radiological evaluation of patients with VUR. Treatment of patients with VUR should be directed at preventing new renal injury and preserving renal function.

Acute rejection episodes in pediatric renal transplant recipients with cytomegalovirus infection

CMV infection is the most important opportunistic virus infection after renal transplantation leading to increased patient mortality, graft loss, risk for acute rejection episodes and impaired renal function. The potential impact of prophylactic anti-viral therapy on long-term graft outcome is relevant. The aim of this study was to evaluate the incidence of CMV infection, its risk factors and long-term outcome in children after renal transplantation. 103 children (mean age 10.6 +/- 5.3, range 1.6-22.0 yr) were monitored weekly for pp65 for the first 6-8 wk after renal transplantation, followed by a monthly monitoring for the first year. CMV infection occurred in 23/103 children (21.1%) with 10 patients (9.7%) developing CMV disease characterized by positive pp65 in the presence of organ involvement. The CMV R-/D+ and R+/D+ serostatus was significantly associated with an increased risk of CMV infection (p < 0.0001 and p = 0.009). 14/28 R-/D+ patients developed CMV infection despite prophylactic treatment with CMV hyperimmune globulin. The incidence of acute rejection episodes after or during CMV infection was significantly increased (p = 0.003) and the D+ serostatus was significantly associated with acute rejection episodes within the first year after transplantation (p = 0.006). In summary the overall incidence of CMV infection in this single center experience is 21.1%. The D+ serostatus represents a serious risk factor for both CMV infection and acute rejection episodes. In future the potential impact of different modalities of prophylactic anti-viral therapy on the prevention of acute rejection should be considered.

Early steroid withdrawal in pediatric renal transplant on newer immunosuppressive drugs

Steroids have been a cornerstone in renal transplant immunosuppression. New immunosuppressive drugs have led to protocols using early steroid withdrawal or complete avoidance. A prospective protocol in 23 pediatric renal transplant (ages 2-14 yr) who received decreasing steroid doses stopping at day 7 post-Tx, FK, and MMF were compared with a CsA, AZT, historically matched steroid-based control group. Basiliximab was used in two doses. Anthropometric, biochemical variables, AR rates, and CMV infection were evaluated and compared using Student's t-test and regression analysis. A better growth pattern was seen in steroid withdrawal group. GFR rate and serum glucose were similar in both groups. Total serum cholesterol levels were significantly lower in steroid withdrawal group. The incidence of AR at 12 months was 4.3% in steroid withdrawal group vs. 8.6% in steroid-based group (p = ns). No difference in CMV infection was observed. Hemoglobin levels were low during the first months in both groups; reached normal values after six months. SBP became higher at 12 months in steroid-based group. Patient and graft survival was 98% in both groups at one-yr post-transplant. Early steroid withdrawal was efficacious, safe, and did not increase risk of rejection, preserving optimal growth, renal function, and reducing cardiovascular risk factors.

Outcome of Living Kidney Transplant: Pediatric in Comparison to Adults

BACKGROUND

Renal transplantation is the most optimal way to manage children with end-stage renal disease. Despite its benefits, pediatric renal transplantation is a challenge for several transplantation centers in terms of achieving a satisfactory outcome. We sought to compare the long-term outcome of pediatric versus adult recipients who underwent renal transplantation.

METHOD

We examined, 2631 recipients of a first kidney from a living donor between 1982 and 2002. The two groups were matched for immunosuppressive therapy and number of HLA mismatches. The patients were divided into a pediatric (n=301; age <or= 18 years) and an adult group (n=2330; age > 18 years) to compare 5-year patient and graft survivals.

RESULTS

The mean ages of the pediatric and adult groups were 40 +/- 13 and 14 +/- 13 years, respectively. The 5-year graft survival was lower among the pediatric versus the adult group (56% vs 68%; P=.015) with no difference in patient survival (88% vs 86%; P>.05).

CONCLUSION

The poorer graft survival in pediatric transplantation may be due to the nature of pediatric transplantation, in terms of inconsistent adherence to medication regimens, worse side effects of medications, higher rate of graft rejection due to recurrent disease, and more intense immunoreactivity of children.