Renal transplantation in children with posterior urethral valves

Clean Intermittent Catheterization in Children under 12 Years Does Not Have a Negative Impact on Long-Term Graft Survival following Pediatric Kidney Transplantation

BACKGROUND

Congenital anomalies of the kidneys and urinary tract (CAKUTs) are one of the most prevalent primary causes of end-stage renal disease (ESRD) in young children, and approximately one-third of these children present with lower urinary tract dysfunction (LUTD). Many children with LUTD require therapy with clean intermittent catheterization (CIC). CIC commonly leads to bacteriuria, and considerations have arisen regarding whether CIC in immunosuppressed children is safe or whether repeated febrile urinary tract infections (UTIs) may lead to the deterioration of kidney graft function.

MATERIAL AND METHODS

We retrospectively reviewed all cases of primary kidney transplantation performed in our center between 2001 and 2020 in recipients aged less than twelve years. The number of episodes of febrile UTIs as well as the long-term kidney graft survival of children undergoing CIC were compared to those of children with urological causes of ESRD not undergoing CIC, as well as to those of children with nonurological causes of ESRD.

RESULTS

Following successful kidney transplantation in 41 children, CIC was needed in 8 of these patients. These 8 children undergoing CIC had significantly more episodes of febrile UTIs than did the 18 children with a nonurological cause of ESRD (p = 0.04) but not the 15 children with a urological cause of ESRD who did not need to undergo CIC (p = 0.19). Despite being associated with a higher rate of febrile UTIs, CIC was not identified as a risk factor for long-term kidney graft survival, and long-term graft survival did not significantly differ between the three groups at a median follow-up of 124 months.

CONCLUSIONS

Our study demonstrates that, under regular medical care, CIC following pediatric transplantation is safe and is not associated with a higher rate of long-term graft loss.

Does bladder augmentation negatively affect renal transplant outcome in posterior urethral valve patients?

OBJECTIVE

Although renal transplant (RT) is a safe and effective treatment for end-stage renal disease, the outcome of RT has been mixed for posterior urethral valve (PUV) patients. In addition, some PUV patients need an augmentation cystoplasty (AC), which may negatively affect their RT outcome. The aim of this study is to compare RT outcome between PUV children with and without AC.

MATERIALS AND METHODS

Between 1985 and 2012 a total of 309 children received 369 RTs at our institution. Among these patients, 36 were had classified as having PUV. Of these, 12 underwent an AC before RT (AC group) and 24 did not (controls). Data, including age at transplant, allograft source, urological complications, urinary tract infection (UTI) incidence, the presence of vesicoureteral reflux (VUR), and patient and graft survival, were compared between groups.

RESULTS

Mean age at RT and mean follow-up were 7.6 versus 7.9 years and 8.9 versus 7.9 years in the AC group and in the control group, respectively (not significant [NS]). Allografts were from living donors in 50% of the AC group and in 41.6% of the controls (NS). The rate of UTI was 0.02 UTI/patient/year and 0.004 UTI/patient/year in the AC and control group, respectively (p = 0.001). Of the nine patients with UTI in the augmented group, five (55.5%) had VUR, while 5/8 (62.5%) patients in the control group with UTI had VUR. All patients with VUR in either group had UTIs previously. Of the five AC patients with more than three UTIs, two (40%) were non-compliant with clean intermittent catheterization (CIC), and UTI incidence was not associated with either a Mitrofanoff conduit or the urethra being used for CIC. Graft function at the end of study was 87.8 ± 40.5 ml/min/m(2) in the AC group and 88.17 ± 28.20 ml/min/m(2) in the control group (NS). The 10-year graft survival rate was 100% in AC group and 84.8% in controls. Two patients in the AC group lost their grafts (mean follow-up 13.3 ± 0.8 years) and five in the control group (mean follow-up 7.1 ± 4.7 years).

CONCLUSIONS

Bladder augmentation does not negatively affect renal outcome in PUV patients undergoing transplantation. However, recurrent UTIs are more frequent in transplanted PUV patients with an AC than in those without AC, and they are generally related to non-compliance with CIC or the presence of VUR but, mostly, they will not result in impaired graft function.

Long-term consequences of posterior urethral valves

Posterior urethral valves (PUV) are the most common congenital cause of bladder outlet obstruction in infancy, and it is the effect of this obstruction on the bladder and the kidneys that will decide a patient's prognosis. With the improvements in diagnosis and treatments, what was previously a poor prognosis for boys with PUV has improved, and more patients will encounter the long-term sequelae of PUV during puberty and adulthood. In these patients the long-term prognosis in terms of renal and bladder function and fertility, as well as the risk of malignancy in those whose bladders were augmented with gastrointestinal segments, is still a matter of great concern and all of these topics will be discussed in this article.

Impact of posterior urethral valves on pediatric renal transplantation: a single-center comparative study of 297 cases

OBJECTIVE

  This is a retrospective long-term evaluation of the renal allografts and bladder functions in pediatric recipients who had posterior urethral valves (PUV).

PATIENTS AND METHODS

Between March 1976 and February 2009, 2033 live-donor renal transplantations were carried out in our center. Of these, 297 (14.2%) were in the pediatric age (≤18 yr). The pediatric recipients included 20 (6.7%) boys who developed end-stage renal disease as a late complication of PUV and recognized as group I while the remaining 277 pediatric recipients were defined as group II. Demographic characteristics, post-transplant complications and graft function were compared among both groups. Patient and graft survivals of both groups were also estimated. Moreover, the bladder function of the study group was evaluated by urodynamic studies.

RESULTS

Patients with PUV (group I) were significantly younger than group II. Although the overall rate of urological complications in both groups was essentially similar, the incidence of urinary fistulae and urinary tract infection were higher in group I. The mean (SD) follow up periods for group I and II were 4.7 (4.1) and 6.4 (4.8) yr, respectively. At last follow up the serum creatinine values were similar among patients of both groups. Moreover, there were no differences in graft or patient survival at five and 10 yr. Detrusor over-activity could be elicited in only one of group I patients. Schafer nomogram showed non-obstructed pattern in all cases.

CONCLUSION

Good functional outcome could be achieved for patients with PUV if renal transplantation is necessary. Pre-transplant surgical procedures may be required such as nephroureterectomy, cytoplasty or injection of refluxing ureters. A robust anti-refluxing uretero-vesical anastomosis is important, and can be achieved by a Lich-Gregoir procedure.

Treatment strategies to minimize or prevent chronic allograft dysfunction in pediatric renal transplant recipients: an overview

Long-term allograft survival poses a major problem in pediatric renal transplantation, with allograft nephropathy being the principal cause of graft failure after the first post-transplant year. The mechanisms of nephron loss resulting in graft dysfunction are multiple, comprising both immunologic factors such as acute and chronic antibody- or T-cell-mediated rejection and non-immunologic components. The latter include peri-transplant injuries and renovascular lesions (renal artery stenosis, thrombosis) as well as cardiovascular risk factors such as arterial hypertension and hyperlipidemia. Another relevant issue leading to progressive nephron loss and declining kidney transplant function is acute and chronic nephrotoxicity induced by the calcineurin inhibitors (CNIs) ciclosporin (cyclosporine microemulsion) and tacrolimus. Furthermore, the presence of an abnormal lower urinary tract as well as bacterial (recurrent pyelonephritis) and viral (cytomegalovirus [CMV], polyomavirus [BK virus; BKV]) infections are crucial factors involved in the incidence of chronic allograft dysfunction and graft failure. Renovascular lesions and lower urinary tract obstruction are typical indicators for surgical intervention. The aim of treatment in pediatric patients with renal failure secondary to a dysfunctional lower urinary tract is to create a sterile, continent, and nonrefluxive reservoir. Surgical techniques such as bladder augmentation and the introduction of intermittent catheterization and anticholinergic therapy have significantly improved graft outcome. Arterial hypertension, another factor responsible for graft function deterioration in pediatric renal transplant recipients, is controlled preferably by the use of angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists, which are known to possess nephroprotective properties in addition to their potent antihypertensive effects. Although treatment of subclinical rejection with augmented immunosuppression has been associated with better graft survival, an increase of the immunosuppressive level to avoid subclinical rejection should be weighed against the risk of infection. The majority of viral infections affecting kidney allografts are caused by CMV and BKV. Antiviral CMV prophylaxis or pre-emptive therapy with ganciclovir has been shown to have beneficial effects in the pediatric renal transplant population. Treatment of BKV-induced nephropathy is based on reduction of the immunosuppressant therapy, although specific antiviral agents such as cidofovir and leflunomide are known to inhibit BKV. However, cidofovir itself is nephrotoxic and should therefore be administered cautiously to pediatric renal transplant patients. Since CNIs are likewise known for their nephrotoxic effects, especially with long-term use, alteration of the immunosuppressant regimen is necessary in case of deteriorating graft function due to CNI-induced histopathologic changes. Complete CNI avoidance seems inappropriate because, in this situation in pediatric renal transplant recipients, other relatively potent immunosuppressant agents such as lymphocyte-depleting antibodies, which are frequently accompanied by a higher incidence of infections, are needed for rejection prophylaxis. CNI withdrawal and switching of the immunosuppressant regimen from CNI therapy to sirolimus may be an option for some pediatric renal transplant patients with less advanced graft function deterioration. Nevertheless, potential adverse events such as aggravation of proteinuria, hyperlipidemia, myelosuppression, and hypergonadotropic hypogonadism have to be considered, and controlled studies are lacking. At present, an immunosuppressant maintenance therapy composed of low-dose tacrolimus or ciclosporin (CNI minimization) and mycophenolate mofetil with low-dose corticosteroids appears to be the most promising strategy to adopt in pediatric renal transplant recipients at low or normal immunologic risk.

Laparoscopic ureterocystoplasty before kidney transplantation

PURPOSE

To describe the technique of total laparoscopic ureterocystoplasty.

MATERIALS AND METHODS

Laparoscopic ureterocystoplasty was performed to optimize the bladder function before kidney transplantation in a 23-year-old man. This patient had undergone bilateral cutaneous ureterostomy with fulguration of a posterior urethral valve at the age of 11 months. He underwent open surgical removal of multiple renal stones at age 10. He progressed to chronic renal failure at the age of 20, at which time hemodialysis was initiated. Because of grade IV vesicoureteral reflux and a poorly compliant bladder, the patient underwent laparoscopic ureterocystoplasty.

RESULTS

The patient's lower urinary tract symptoms improved, and a urodynamic study performed after 6 months revealed a compliant bladder. Subsequently, a right nephrectomy and a live-donor renal transplantation from his mother were performed. At 1-year follow-up, his renal parameters were within normal range, he does not have any significant residual urine or urinary symptoms.

CONCLUSION

Laparoscopic ureterocystoplasty is an excellent option for a poorly compliant bladder, especially when a patient has had multiple open surgeries and is awaiting renal transplantation.

Increased urologic complications in children after kidney transplants for obstructive and reflux uropathy

In the cyclosporine era, reports on pediatric kidney transplant (KTx) patients with obstructive and reflux uropathy are limited by small numbers, short follow-up, and/or lack of control groups. Our single-center study evaluated long-term outcomes (patient and graft survival, urinary tract infections [UTIs], urologic complications) in a large cohort of KTx recipients (<20 years old). We matched our 117 study patients with obstructive and reflux uropathy with 117 controls whose KTx was needed for other reasons; all 234 underwent their KTx between April 25, 1984, and October 23, 2002. The mean age was 8.0 +/- 6.2 years; mean follow-up, 133 +/- 67 months. The urologic complication rate was higher in study patients (43%) than in controls (11%) (p < 0.0001), as was the UTI rate (45% vs. 2%; p < 0.0001). The metabolic acidosis and UTI rates were higher in study patients who did (vs. did not) undergo bladder augmentation (p < 0.0001). We found no significant difference between study patients and controls in patient or graft survival, acute or chronic rejection, or mean estimated glomerular filtration rates. Unique to our study is the finding of higher metabolic acidosis and UTI rates in study patients who underwent bladder augmentation.

Posterior urethral valve: Outcome of antenatal intervention

INTRODUCTION AND AIM

Antenatal treatment of obstructive uropathy, although widely performed, remains controversial. This study evaluated the long-term outcome of managing patients with posterior urethral valves (PUV), highlighting the effect of antenatal vesicoamniotic shunt placement for patients who underwent fetal surgery.

METHODS

The medical records of 58 patients with PUV were retrospectively reviewed from June 1998 to June 2004. On the basis of prenatal assessment of sonographic findings and serial urinary electrolytes and protein measurements, patients were divided into two groups: group 1 comprised patients who had antenatal vesicoamniotic shunt placement whereas group 2 comprised patients who underwent postnatal surgical correction of PUV. Their outcomes and long-term results were evaluated.

RESULTS

Patients were followed up from 6 months to 6(1/2) years (mean 3.9 years). Group 1 included 12 patients who had vesicoamniotic shunt placement and were confirmed postnatally to have PUV. Four patients out of 12 died (33.3%); three out of the eight living patients had perinatal complications. Of the eight living patients, three (37.5%) underwent valve ablation and five (62.5%) underwent urinary diversion (three vesicostomies and two cutaneous ureterostomies). Renal function returned to normal in only four patients (50%). Radiological abnormalities (hydronephrosis and/or reflux) resolved in three (37.5%) patients, was downgraded in one (12.5%) patient and persisted in four patients (50%). Group 2 included 46 patients who were treated postnatally. Thirty-five patients (76%) underwent primary valve ablation, while 11 (24%) underwent urinary diversion (seven vesicostomies, four cutaneous ureterostomy and one pyelostomy). Renal function returned to normal in all patients who underwent valve ablation, except in three, while renal function returned to normal in only three of 11 patients who underwent urinary diversion. Radiological hydronephrosis and/or reflux resolved in 28 patients (60.9%), was downgraded in six patients (13%) and persisted in 12 patients (26.1%).

CONCLUSIONS

Antenatal vesicoamniotic shunt placement makes no difference to the outcome and long-term results of patients with PUV and debate about its efficacy on renal outcome remains. Primary valve ablation is the keystone of treatment for patients with PUV that might achieve the primary goal of nephron preservation. The lowest creatinine concentration in the first year of life is the most appropriate predictor of future renal function.

RENAL TRANSPLANTATION IN CHILDREN WITH RECONSTRUCTED BLADDERS

In this article, we review the outcome and complications of renal transplantation in patients with reconstructed bladders and address specific issues and controversies regarding the management of such cases. Twenty-five articles covering the subjects of renal transplantation, lower urinary tract anomalies, and bladder reconstruction have been selected. Although urologic complications are higher when kidneys are transplanted into reconstructed bladders or urinary diversions, the graft and patient survival rates in most series are comparable with those transplanted into nonreconstructed bladders. The reported series of renal transplantation into abnormal bladders are small, and controlled studies are lacking. Bladder reconstruction should be performed before transplantation when clinically indicated.

Successful renal transplantation in children with posterior urethral valves

PURPOSE

The treatment of children with posterior urethral valve (PUV) and end-stage renal disease can be challenging. Some series have had poor outcomes after renal transplantation with an increased risk of graft dysfunction and urinary tract infections. We present our experience with a pediatric population and compare it to all the other pediatric renal transplants done at our institution.

MATERIALS AND METHODS

We identified 10 patients with PUV who underwent a total of 13 renal transplants between 1990 and 2000. The comparison group included 120 transplants done in 95 patients during the same period. Cumulative allograft survival and function were recorded.

RESULTS

Overall patient survival in the PUV group was 100%. Mean age at transplant in the PUV group was 10.0 years and mean followup was 3.9 years. Six patients underwent high proximal urinary tract diversion, while the remainder had primary transurethral valve ablation. Three patients had bladder augmentation before transplantation. Cumulative allograft survival in the PUV group at 1 and 5 years was 85% and 64%, respectively. Of the 10 patients 9 currently have functioning living related donor transplants. One patient lost 3 cadaveric donor transplants to chronic rejection. No patients lost grafts due to infection or bladder dysfunction. Mean serum creatinine of the functioning grafts was 1.1 mg/dl.

CONCLUSIONS

Renal transplantation can be performed safely and effectively in patients with PUV, including those who have undergone previous proximal urinary tract diversion. Preoperative bladder management and continued monitoring of bladder and kidney function postoperatively are paramount in the preservation of allograft function.

Long-term results of pediatric renal transplantation into a dysfunctional lower urinary tract

BACKGROUND

The authors reviewed their long-term experience with pediatric renal transplantation into a dysfunctional lower urinary tract to evaluate the results of contemporary lower urinary tract evaluation and management on graft survival and function.

METHODS

Between 1990 and 1996, 21 renal transplants were performed in 20 children with dysfunctional lower urinary tracts and 61 transplants were performed in 61 patients with normal lower urinary tracts. The minimum follow-up was 36 months (mean, 62.0 +/- 19.6 months). The cause of lower urinary tract dysfunction included posterior urethral valves (n=13), prune belly syndrome (n=4), meningomyelocele (n=2), and urogenital sinus abnormality (n=1). Urodynamics were performed on all children with dysfunctional lower urinary tracts. Using these perioperative assessments, lower tract management strategies were devised, including timed voiding alone (n=6), clean intermittent catheterization (n=8), bladder augmentation (n=4), and supravesical urinary diversion (n=2).

RESULTS

Overall 5-year actuarial patient and graft survival rates were 100% versus 95% (P=not significant [NS]) and 83% versus 69% in the dysfunctional and normal urinary tract groups (P=NS), respectively. Mean serum creatinine levels in dysfunctional and normal urinary tract patients with functioning grafts at 3 years were 1.3 +/- 0.5 and 1.3 +/- 0.7 mg/dL, respectively (P=NS). However, 35% of patients with a dysfunctional lower urinary tract experienced urologic complications.

CONCLUSIONS

Pediatric renal transplantation into a dysfunctional lower urinary tract yields outcomes comparable to transplantation into the normal lower urinary tract. Because of the high urologic complication rates, careful surveillance of lower urinary tract function by urodynamic evaluation is essential to optimize these outcomes.

Limited surgical interventions in children with posterior urethral valves can lead to better outcomes following renal transplantation

There is currently no consensus as to the most appropriate means by which children with posterior urethral valves (PUV) are to be managed prior to transplantation. We compared (i) renal allograft survival and function in patients with PUV vs. those with non-obstructive causes of ESRD and (ii) graft outcomes in children who had limited interventions (Group 1) vs. those with more extensive urologic surgeries to decompress the urinary tract (Group 2). Twenty-six pediatric renal transplant recipients had ESRD due to PUV (Group 1, n = 16; Group 2, n = 10). The study group was compared to 23 matched controls with ESRD due to non-obstructive causes. Five yr patient and graft survival was similar in all patients with PUV (Groups 1 and 2) when compared to all other kidney recipients in the transplant program, 96.2% vs. 98.0% and 87.5% vs. 87.0%, respectively. Although calculated creatinine clearance (Ccr), was similar between the PUV group and controls for the first 4 yr, the 5 yr graft function was significantly lower in the PUV group. (53.7 +/- 15.7 vs. 70.2 +/- 21.0 mL/min/1.73 m2; p = 0.03). When the two PUV groups were compared, graft survival was equivalent, but graft function was significantly better at 5 yr in Group 1(60.4 +/- 10.8 vs. 33.8 +/- 9.3 mL/min/1.73 m2; p = 0.02). Thus, patients with PUV managed by a limited intervention approach of vesicostomy with delayed valve ablation or primary valve ablation, had better outcomes. When ESRD is virtually certain, additional pre-transplant surgeries affecting the urinary tract should be avoided.

Ureterocystoplasty (bladder augmentation) with a solitary kidney

Children who develop end-stage renal disease (ESRD) as a result of obstructive uropathies require evaluation and treatment of associated bladder dysfunction to ensure a good outcome following renal transplantation. Bladder dynamics can often be optimized medically, although surgical intervention is occasionally necessary. For those patients who require bladder augmentation, the use of a dilated native ureter (ureterocystoplasty) is preferred to the more commonly used intestine or stomach (enterocystoplasty), which carry a higher risk of complications. Unfortunately, most patients do not have a suitable anatomy for ureterocystoplasty and, by necessity, intestine or stomach has to be utilized. Herein, we describe the successful application of ureterocystoplasty in the presence of ESRD and a solitary kidney prior to renal transplantation. We believe that owing to the many advantages of native urothelium, every effort should be made to use ureter and avoid the use of intestine.

The valve bladder: etiology and outcome

The infravesical obstruction created by posterior urethral valves produces a series of structural, biochemical, and functional changes in these boys' bladders that begins during fetal life. Any change can be irreversible and result in the alterations in bladder function that can be found in some of these patients. Bladder instability, poor compliance, and myogenic failure are the three most common urodynamic patterns and are also responsible for some of these patients' poor long-term prognosis. Treatment of bladder dysfunction in these patients is basically directed toward improving their kidney function prognosis and also to avoid the urinary incontinence presented secondarily by some valve bladders.

Does treatment of bladder dysfunction prior to renal transplant improve outcome in patients with posterior urethral valves?

Fourteen patients with posterior urethral valves and end-stage renal failure were urodynamically evaluated in order to identify and correct any bladder dysfunction before renal transplant. Of the 14 patients, during filling, six had normal bladder function, two had an over-distended bladder (one with instability), one had instability, four had poor compliance, and one had a very reduced bladder capacity. During the voiding phase, one had a myogenic failure and another had detrusor-sphincteric dyssynergia. Four patients underwent bladder augmentation. Three were managed with anticholinergic therapy and two required clean intermittent catheterization owing to post-voiding residual urine. A renal transplant was performed in all of these patients at a mean age of 8.2 years. We compared outcome in these 14 patients with bladder dysfunction treated before transplantation with outcome in a matched control group of 14 transplant patients. Graft function and survival were similar in both groups. We believe that urodynamic studies must be included in the pretransplant evaluation of patients with posterior urethral valves in order to diagnose any bladder dysfunction and commence appropriate treatment to avoid any negative influence on graft function.

Posterior urethral valves: long-term renal function consequences after transplantation

PURPOSE

We assessed the long-term efficacy of renal transplantation in children with posterior urethral valves.

MATERIALS AND METHODS

We retrospectively compared the outcomes of renal transplantation in 66 children with posterior urethral valves and 116 with malformation uropathies (controls).

RESULTS

Graft survival in the posterior urethral valves and control groups was 69 and 72% at 5 years, and 54 and 50% at 10 years, respectively (not statistically significant). A statistically significant increase in serum creatinine was noted at 10 years in children with posterior urethral valves but not in controls (p < 0.05).

CONCLUSIONS

Renal transplantation in children with posterior urethral valves is not associated with a high rate of failure. However, long-term deterioration of graft function is likely related to lower urinary tract dysfunction.

Kidney transplantation to patients with congenital malformations of the distal urinary tract

Fourteen of 1000 consecutive kidney transplant patients had congenital malformations affecting the bladder or urethra: six had congenital valvulus of the urethra, two congenital sclerosis of the bladder outlet, and six a neurogenic bladder. Pretransplant surgery had been performed in all patients: reimplantation of ureter (n = 11), resection of congenital valvulus (n = 7), and nephrectomy (n = 6). Four patients had an intestinal bladder. Age was 0-17 (median 1) years at diagnosis. Follow-up time was 3-10 (median 5) years. Special transplant surgery techniques were required in five patients. Patient survival after 2 years was 100% and graft survival 93%. No graft was lost due to outflow obstruction, infection or other causes related to the underlying disorder. Late technical problems were seen in two patients. Urinary tract infections were reported in 13 patients before transplantation and in eight after. Results of transplantation were excellent. Infections and surgical problems had a minor impact on outcome.

Long-term results of renal transplantation into the valve bladder

Between 1970 and 1990 renal transplantation was performed in 16 patients with a history of posterior urethral valves. While 10 patients had undergone supravesical urinary diversion before the development of end stage renal disease, all but 1 transplant were drained to the unaugmented native bladder. The 2 and 5-year graft survival rates were 70% and 59%, respectively. Of the 15 surviving patients 11 have allografts that are functioning at a mean of 86 months after transplantation with a mean serum creatinine of 2.0 mg./dl. Urological complications occurred in 19% of the transplants. No detrimental effect of the valve bladder on long-term allograft survival or function was apparent. With appropriate treatment of vesical dysfunction, these patients can be expected to have graft function comparable to the general transplant population despite use of the unaugmented native bladder.

Renal transplantation in young boys with posterior urethral valves: preliminary report

Seven boys (mean age 38 months) with posterior urethral valves underwent renal transplantation between June 1988 and August 1991. Urodynamic studies were performed before transplantation in 6/7 patients. In 4 the investigation indicated bladders of capacity and compliance which were deemed suitable for transplantation. Two patients had poorly compliant bladders; one of these underwent bladder augmentation before engraftment and the other proceeded to transplantation without bladder surgery. Six patients have functioning renal allografts with a mean follow-up of 1.3 years and a mean plasma creatinine of 51.6 mumol/l. Mean glomerular filtration rate (ml/min/1.73 m2 SA) 6 months after transplantation was 76.8 and at 1 year it was 84.5. In one patient early rejection was followed by transplant nephrectomy. Careful pre-operative evaluation is mandatory for a successful outcome of renal transplantation in young boys with posterior urethral valves.

Results of renal transplantation in boys treated for posterior urethral valves

The results of renal transplantation in boys treated for posterior urethral valves were evaluated and compared with a matched control group. Patient and graft survival was equal in both groups, although serum creatinine levels were slightly higher in the posterior urethral valves group. Postoperative complications, such as urinary tract infections, occurred more frequently in the posterior urethral valves group. Urodynamic evaluation was performed before transplantation in 11 of 20 patients. Adequate treatment of bladder dysfunction, such as poor compliance and/or hyperreflexia, is essential in diminishing the risks of secondary graft damage due to severe bladder dysfunction.

Non-immunological risk factors in paediatric renal transplantation

In paediatric renal transplantation, non-immunological risk factors account for about one-third of graft losses. Recurrence of original disease is observed mainly in primary hyperoxaluria and glomerulopathies such as steroid-resistant nephrotic syndrome and membranoproliferative glomerulonephritis. In both glomerulopathies, 20% of grafts are lost from recurrence. Vascular thrombosis is, in most series, the second cause of graft loss in children, particularly in young recipients or with young donors (under 5 years of age). Non-compliance with treatment is a common non-immunological factor in adolescent recipients, which may trigger a severe rejection process resulting in graft loss. The role of factors related to graft preservation and intra- and post-operative management (ischaemia time, delayed graft function) or to cytomegalovirus infection is less obvious in our series. Prevention of vascular thrombosis and of non-compliance is most important in order to improve the results of paediatric renal transplantation.