The Long-Term Outcome of Posterior Urethral Valves Treated with Primary Valve Ablation and Observation

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.

Antenatal hydronephrosis: evaluation and outcome

We present a comprehensive and current review of the etiology, evaluation, treatment, and outcome of antenatal hydronephrosis. When a diagnosis of antenatal hydronephrosis is made, many questions regarding pregnancy, prenatal care, intervention, and what may be expected after birth are raised. Debate and controversy exist on the diagnosis and subsequent evaluation and management of the child with antenatal hydronephrosis. A review of the literature and our own experience with antenatal hydronephrosis are presented in order to guide the physician who is caring for mother and child.

The valve bladder syndrome: pathophysiology and treatment with nocturnal bladder emptying

PURPOSE

We determine the etiology and treat the specific pathophysiology of the valve bladder syndrome.

MATERIALS AND METHODS

Defined as persisting or progressive severe hydroureteronephrosis without residual or recurrent obstruction, the valve bladder syndrome developed in 18 boys who underwent successful ablation of the posterior urethral valve. Serial radiographic, renal function, renographic, urodynamic and perfusion studies were performed for a mean time of 11 years.

RESULTS

The cause of the valve bladder syndrome proved to be sustained bladder over distention due to a combination of polyuria with 24-hour urine volume greater than 2 l. in 10 boys, impaired bladder sensation in 18 and residual urine volume in 14. Treatment of over distention during the daytime alone was unsuccessful. Nocturnal bladder emptying was performed with an indwelling nighttime catheter, intermittent nocturnal catheterization and/or frequent nocturnal double voiding. Hydronephrosis markedly improved once nocturnal bladder emptying was started and was comparable to the results after urinary diversion.

CONCLUSIONS

The valve bladder syndrome is not due to a permanent prenatal alteration in bladder anatomy and function. Instead, it appears to result from sustained postnatal bladder over distention due to a combination of polyuria, impaired bladder sensation and residual urine volume, which represent sequelae of prenatal valve injury. These factors synergize to prevent bladder normalization after valve ablation and progressively reduce functional bladder capacity to maintain bladder over distention. Bladder decompensation, upper tract dilation, and renal injury develop and characterize the valve bladder syndrome. Because current therapy, including intermittent catheterization, leaves the bladder full throughout the night, it remains markedly over distended. Nocturnal bladder emptying is the specific antidote for this pathophysiological situation, and results in prompt and impressive improvement or elimination of hydronephrosis in these and similar groups of patients. This response to nocturnal bladder emptying suggests that the bladder is not the primary cause for the valve bladder syndrome.

Fetal surgery for posterior urethral valves: long-term postnatal outcomes

OBJECTIVE

Fetal intervention for obstructive uropathy was first performed at the University of California, San Francisco in 1981. Indications for treatment were bilateral hydronephrosis with oligohydramnios. Preintervention criteria included fetal urinary electrolytes with beta-microglobulin levels, karyotyping, and detailed sonography specifically looking for renal cortical cysts. We reviewed the outcomes of children who underwent fetal intervention with specific long-term follow-up in patients who were found postnatally to have posterior urethral valves.

METHODS

A retrospective review of the University of California, San Francisco fetal surgery database was performed for patients with a prenatal diagnosis of obstructive uropathy. Medical records from 1981 to 1999 were reviewed. Long-term follow-up was documented if the cause of the urinary tract obstruction was posterior urethral valves. We collected data points, focusing on time and type of intervention, fetal urinary electrolytes, appearance of fetal kidneys, present renal function, length of follow-up, and present status of the urinary tract.

RESULTS

Forty patients were evaluated for fetal intervention; 36 fetuses underwent surgery during this time period. Postnatal confirmation of posterior urethral valves was demonstrated in 14 patients. All patients had favorable fetal urinary electrolytes. Mean gestational age at intervention was 22.5 weeks. The procedures performed included creation of cutaneous ureterostomies in 1, fetal bladder marsupialization in 2, in utero ablation of valves in 2, and placement of vesicoamniotic catheter in 9. Six deaths occurred before term delivery with premature labor and the newborns succumbing to respiratory failure. One pregnancy was terminated electively because of shunt failure and declining appearance of fetal lungs and kidney. The remaining 8 living patients had a mean follow-up of 11.6 years. Chronic renal disease with abnormal serum creatinine was present in 5 patients. Two patients have undergone renal transplantation, and 1 is awaiting organ donation. Five of the 8 living patients have had urinary diversion with vesicostomy, cutaneous ureterostomy, or augmentation cystoplasty with later reconstruction.

CONCLUSIONS

Fetal intervention for posterior urethral valves carries a considerable risk to the fetus with fetal mortality rate of 43%. The long-term outcomes indicate that intervention may not change the prognosis of renal function or be a predictor for possible urinary diversion. Despite all of these patients' having favorable urinary electrolytes, this did not seem to have any implication postnatally. When counseling families about fetal intervention, efforts should be focused on that intervention may assist in delivering the fetus to term and that the sequelae of posterior urethral valves may not be preventable. Fetal surgery for obstructive uropathy should be performed only for the carefully selected patient who has severe oligohydramnios and "normal"-appearing kidneys.

Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in children

Most children with end-stage renal failure are born with abnormal kidneys, with fetal obstructive uropathy accounting for about half these cases. Posterior urethral valves (PUV) is overwhelmingly the most common, specific diagnosis, and is confined to boys. In general, the condition is sporadic, although familial cases have been reported, perhaps suggesting that genetic factors play a role in pathogenesis. PUV can present antenatally, detected on routine fetal ultrasonography, or postnatally, when it is associated with renal failure and bladder dysfunction. Advances in postnatal surgery and medical management have reduced the mortality in PUV, but it is uncertain whether antenatal diagnosis or treatment (eg, with vesicoamniotic shunts) improves long-term renal outcome. Other disorders associated with human fetal obstructive uropathy are urethral atresia, the prune belly syndrome, and multicystic dysplastic kidney. The nephropathy associated with fetal obstructive uropathy is renal dysplasia and comprises undifferentiated and metaplastic tissues. Several studies in animals and in humans suggest that fetal urine flow impairment causes deregulation of renal precursor cell turnover and expression of growth factor/survival and transcription factor genes. Furthermore, some of these morphologic and molecular changes can be ameliorated experimentally by fetal surgical decompression or administration of specific growth factors.

Posterior urethral valves presented at birth despite normal prenatal ultrasound scans

Most patients with significant posterior urethral valves are identified antenatally. However, even with a normal antenatal ultrasound scan, posterior urethral valves may be detected after birth. We present a patient with significant upper urinary tract involvement identified 2 days after birth, despite a normal third-trimester antenatal ultrasound scan.

Obstructive nephropathy in children: long-term progression after relief of posterior urethral valve

BACKGROUND

Approximately one third of children with end-stage renal disease have the illness because of urinary tract malformations, obstructive uropathy, and hypoplasia/dysplasia. The significant drop in infant mortality from obstructive uropathies in recent decades, attributable to prenatal diagnosis with renal ultrasonography and coordinated surgical and medical care, necessitated a reevaluation of the long-term outcome.

METHODS

To that end, we examined the long-term progression of obstructive nephropathy after neonatal relief of posterior urethral valves in our center over a span of 21 years, with diagnosis and care being provided by the same pediatric and urology team.

RESULTS

The 10 consecutive cases of posterior urethral valves represented 7% of all patients with congenital malformative uropathies seen over this period. The following procedures were performed: primary valve ablation (90%) and vesicostomy (40%). Seventy percent of patients progressed to end-stage renal disease over a (mean +/- standard error of the mean) follow-up of 11.3 +/- 2.1 years. The linear plot of the log of the inverse of serum creatinine versus time suggested unrelenting progression. The rate of progression was rapid after serum creatinine exceeded 5 mg/dL but the rate was slow and steady from serum creatinine of 1.5 to 5 mg/dL.

CONCLUSIONS

To test the effect of a therapeutic intervention to ameliorate the rate of progression, this steady and prolonged progression of 0.5 mg/dL per year between serum creatinine concentration of 1.5 to 5 mg/dL would seem the optimal study.

Posterior urethral valves: pre- and postnatal management

Posterior urethral valves are a common problem encountered by pediatric urologists. The diagnosis is most frequently suggested by antenatal screening ultrasound. A variety of pre- and postnatal parameters have been identified to aid in predicting ultimate renal outcome. These prognostic tools are invaluable to the clinician for counseling parents and for choosing appropriate management. Several approaches to the treatment of patients with posterior urethral valves exist, and the ideal strategy is debatable. As technology evolves, more options for early intervention become available. Whether early detection and antenatal intervention improve patient outcome remains to be proven.

Outcomes of primary valve ablation versus urinary tract diversion in patients with posterior urethral valves

OBJECTIVES

Although valve ablation is the treatment of choice for patients with posterior urethral valves, debate continues as to the role of urinary diversion. We sought to retrospectively compare the clinical and radiologic outcomes between valve ablation and urinary diversion for patients with posterior urethral valves.

METHODS

We retrospectively reviewed the records of 50 consecutive patients with posterior urethral valves since January 1995. On the basis of the initial renal function and radiologic findings, patients were divided into three groups: group 1, normal renal function and radiologically normal upper tracts; group 2, normal renal function with hydronephrosis and/or reflux; and group 3, azotemia with hydronephrosis or reflux.

RESULTS

All 22 patients in group 1 were treated with valve ablation. After a mean follow-up of 32 months, these children had normal renal function and no evidence of upper tract deterioration. All 13 patients in group 2 were also treated with valve ablation. The radiologic abnormalities (hydronephrosis, reflux) resolved in 50% of cases, with an average follow-up of 28 months. Of the 15 patients in group 3, 7 underwent valve ablation and 8 underwent urinary diversion. Urinary diversion was performed in patients with renal deterioration and severe hydronephrosis and/or high-grade reflux. Renal function returned to normal in all patients who underwent valve ablation except one; renal function returned to normal in only 3 of 8 patients who underwent urinary diversion. Radiologically, the severity of the hydronephrosis and reflux was downgraded in patients who underwent valve ablation but not in the diverted group.

CONCLUSIONS

Valve ablation is the mainstay of treatment for patients with posterior urethral valves. Prenatal and postnatal factors, such as renal dysplasia and urinary tract infection, respectively, rather than the posterior valve treatment dictate the long-term renal and radiologic outcomes.

Defunctionalized bladders: effects before and after refunctionalization in an animal model

PURPOSE

Bladder behavior after refunctionalization is usually unpredictable. We comparatively analyze various aspects of bladder defunctionalization and subsequent refunctionalization using an animal model.

MATERIALS AND METHODS

A total of 18 rabbits were divided equally into 3 groups. Animals in group 1 underwent 2 successive surgical procedures, including bladder division and reattachment. Bladder division was performed by hemisecting the bladder from dome to trigone into a functioning and nonfunctioning chamber. Bladder reattachment was achieved by reanastomosing both hemibladders. Group 2 animals underwent sham operations, and group 3 animals were age matched normal controls. Serial urodynamic studies and fluoroscopic cystograms were performed in all animals. Gross, histochemical (hematoxylin and eosin, Masson's trichrome and Sirius red) and immunocytochemical (alpha-actin, collagen I and III) analyses, collagen content determination and organ bath studies were performed.

RESULTS

The defunctionalized hemibladders demonstrated lower wet weight, capacity and compliance compared to the functional contralateral and normal control bladders. Refunctionalization of the bladders resulted in a progressive recovery of capacity and compliance with time. The bladder contractile response and connective tissue-to-muscle ratio were abnormal in the defunctionalized segments but normalized after bladder refunctionalization.

CONCLUSIONS

Defunctionalization results in remarkable alterations in bladder growth, capacity, compliance and distribution of connective tissue. However, these bladders demonstrate an innate capacity to recover from these alterations following refunctionalization.

Does neonatal pyeloureterostomy worsen bladder function in children with posterior urethral valves?

PURPOSE

We determine whether long-term bladder dysfunction is more frequent in children with posterior urethral valves who undergo early supravesical urinary diversion (pyeloureterostomy) than in those who undergo valve ablation.

MATERIALS AND METHODS

Urodynamic studies were performed in 59 boys with severe posterior urethral valves who were divided into 2 groups based on initial treatment of valve ablation (30) and bilateral pyeloureterostomy (29).

RESULTS

Of the 59 boys 25 (42%) had a normal bladder, including 11 with an over distended bladder and 34 (58%) had bladder dysfunction, including instability in 22, poor compliance in 9 and myogenic failure in 3. Of the 30 boys initially treated with valve ablation 14 (46.6%) had a normal bladder, including 7 with an over distended bladder and 16 (53.4%) had bladder dysfunction, including instability in 10, poor compliance in 4 and myogenic failure in 2. Of the 29 boys initially treated with temporary bilateral pyeloureterostomy 11 (38%) had normal bladders, 4 with an over distended bladder and 18 (62%) had bladder dysfunction, including instability in 12, poor compliance in 5 and myogenic failure in 1. There were no statistically significant differences in the number or type of bladder dysfunction between the diversion and valve ablation groups.

CONCLUSIONS

Therefore, temporary pyeloureterostomy did not affect bladder function adversely in the long term.

Increased urinary transforming growth factor-beta(1) excretion in children with posterior urethral valves

OBJECTIVES

Patients with posterior urethral valves (PUV) are at significant risk for progression to end-stage renal disease, despite early correction of the obstruction. Experimental models of urinary obstruction demonstrate increased renal expression of the profibrotic inflammatory mediator, transforming growth factor-beta(1) (TGF-beta(1)). Urinary TGF-beta(1) excretion is elevated in certain glomerular diseases, but has not been well studied in patients with obstructive lesions. The objective of this study was to examine urinary TGF-beta(1) excretion in children with PUV.

METHODS

Fourteen patients with PUV, aged 3.2 to 14.5 years, with estimated glomerular filtration rates (GFRs) of 12.8 to 139 mL/min/1.73 m(2) were enrolled. Sixteen normal subjects (9 male, 7 female), aged 4.3 to 20.5 years, served as controls. Total urinary TGF-beta(1) concentration was assayed by enzyme-linked immunoabsorbent assay, and expressed as a ratio to urinary creatinine concentration.

RESULTS

Urinary TGF-beta(1) excretion was significantly greater in patients with PUV (range 0 to 0.063, median 0.019 ng/mg urine creatinine) compared with that of healthy controls (range 0 to 0.022, median 0.005 ng/mg urine creatinine) (P <0.01). There was no correlation between urinary TGF-beta(1) excretion and estimated GFR, past urinary diversion surgery, or bladder wall thickening. Among healthy controls, urinary TGF-beta(1) was not correlated with age or gender.

CONCLUSIONS

Results from this study suggest that TGF-beta(1) may contribute to progressive renal insufficiency in patients with PUV. Further studies are indicated to determine if agents that affect TGF-beta(1) expression, such as angiotensin-converting enzyme inhibitors, can slow the progression of renal disease in PUV.

[Posterior urethral valve: determining factors of long-term results]

Posterior urethral valves (PUV) is the most common congenital urine flow impairment in boys. Long-term prognosis involves: renal function impaired in 30 to 50% of PUV and leading to hyperdiuresis, low GFR and acidosis; bladder urodynamics impaired in 75% of PUV with abnormal urine storage, abnormal micturition and vesicoureteric reflux. Incontinence and recurrent urinary tract infections commonly reflect bladder and renal failures; abnormal bladder outlet leads to incontinence and abnormal ejaculation. The roles of antenatal treatments (vesico-amniotic shunts), neonatal treatments (resuscitation and endoscopic treatment of PUV) and long-term treatments (urinary diversions, bladder augmentation, alpha blockers, anticholinergic, dialysis and renal transplant) in the long-term outcomes of PUV are reviewed.

Delayed presentation of posterior urethral valves: a not so benign condition

PURPOSE

Posterior urethral valves are usually detected during infancy by prenatal sonography. Rarely they may be diagnosed during later childhood, adolescence or even adulthood. Less is known about presentation and outcome in these older patients. We reviewed our experience at 4 institutions with the late presentation of posterior urethral valves.

MATERIALS AND METHODS

A 13-year retrospective review revealed the late presentation of posterior urethral valves in 47 patients 5 to 35 years old (mean age 8). Data collected included presenting symptomatology, radiographic findings and renal function. Statistical analysis determined the relationships among presenting symptoms, patient age at diagnosis and renal function.

RESULTS

The most common presenting symptoms were diurnal enuresis in 60% of the cases, urinary tract infection in 40% and voiding pain in 13%. Other presenting symptoms in less than 10% of the cases included poor stream, gross hematuria and proteinuria. At diagnosis hydronephrosis and vesicoureteral reflux were present in 40 and 33% of the patients, respectively, while serum creatinine was elevated in 35% and end stage renal disease had developed in 10%. The severity of presenting signs and symptoms was significantly associated with renal impairment, while patient age at diagnosis was not.

CONCLUSIONS

Posterior urethral valves is not merely a disease of infancy. Voiding cystourethrography should be considered in boys older than 5 years who have voiding complaints, especially in association with diurnal enuresis or urinary tract infection. Patients who present late with posterior urethral valves are at risk for progression to end stage renal disease.

Outcome of posterior urethral valves: to what extent is it improved by prenatal diagnosis?

PURPOSE

To assess the impact of prenatal diagnosis and evaluation on the outcome of posterior urethral valves we studied all cases of valves detected prenatally, including cases of pregnancy termination due to posterior urethral valves.

MATERIALS AND METHODS

Between 1989 and 1996, 30 neonates with prenatally detected posterior urethral valves were treated at our hospital. The prenatal parameters analyzed were age of gestation at diagnosis, ultrasonographic appearance of renal parenchyma and amniotic fluid volume. Fetal urine was analyzed in 9 cases. We reviewed the outcome of 10 neonates treated for posterior urethral valves which were not diagnosed prenatally during the same period.

RESULTS

Of the 30 neonatal survivors 6 (20%) had renal failure, including end stage renal disease in 2, after a mean followup of 4 years. Renal failure developed in 2 of 5 cases detected before 24 weeks of gestation, in 1 of 6 with oligohydramnios and in 2 of 5 with abnormal parenchymal renal ultrasound. Normal parenchymal ultrasound and amniotic volume could not predict for good outcome. Renal failure developed in 2 of 7 cases predicted by fetal urinalysis as good prognosis and in 1 of 2 cases predicted as poor prognosis. Pregnancy was terminated for posterior urethral valves in 5 cases based on prenatal criteria of severe renal impairment. Considering these cases as poor outcome, the rate of poor prognosis increased from 20 to 31%. Among the 10 neonates without a prenatal diagnosis of posterior urethral valves renal failure developed in 2 (20%), including end stage renal disease in 1.

CONCLUSIONS

When negative parameters were absent and/or fetal urine predicted good outcome there were no cases of end stage renal disease in early infancy, which was a significant help in parent counseling. The predictive value of the currently available prenatal parameters needs to be updated with larger series specifically dealing with posterior urethral valves. According to the current data, the outcome of posterior urethral valves is not yet significantly improved by prenatal diagnosis.

Report of the American Society of Nephrology meetings

PURPOSE

We summarize presentations on topics of interest to the pediatric urologist from the annual meeting of the American Society of Nephrology, November 1996.

MATERIALS AND METHODS

We reviewed all abstracts submitted for presentation and subsequently published in abstract form. Only those abstracts containing information pertinent to the field of pediatric urology were summarized for this report.

RESULTS

A total of 24 abstracts addressing a variety of topics were summarized. Obstructive uropathy was represented by the greatest number of papers and reflects the multiple investigative efforts currently evaluating the cellular aspects of this disorder. The genetic basis of hypercalciuria and the impact of water metabolism on nephroliathisis were also discussed.

CONCLUSIONS

Clinical and basic research activities that are of mutual interest to pediatric urologists and nephrologists are being conducted. The topic of obstructive uropathy has received the greatest attention during the last year. However, additional research, potentially collaborative in nature, on topics such as nephroliathisis and reflux nephropathy should be encouraged.

Antenatal hydronephrosis. Fetal and neonatal management

As many as 1% of newborn infants have a prenatal diagnosis of hydronephrosis or significant renal pelvic dilation. Hydronephrosis often is caused by nonobstructive conditions. The likelihood of significant urologic pathology is directly related to the size of the fetal renal pelvis, and 90% with an anteroposterior diameter more than 2 cm need surgery or long-term urologic medical care. Following delivery, antibiotic prophylaxis should be administered and a renal sonogram and voiding cystourethrogram should be obtained. If there is grade 3 or 4 hydronephrosis, usually a diuretic renogram is recommended also. Pediatric urologic or pediatric nephrologic consultation usually is helpful in planing evaluation and treatment. Prenatal recognition of hydronephrosis allows neonatal diagnosis and treatment of urologic pathology, preventing complications of pyelonephritis and obstruction.

Partial bladder outlet obstruction in the fetal rabbit

PURPOSE

We developed and tested an animal model of bladder dysfunction due to posterior urethral valves using partial outlet obstruction of the fetal rabbit bladder.

MATERIALS AND METHODS

Partial bladder outlet obstruction of fetal rabbit bladders was created on day 23 of gestation. Of the litter of 8 to 10 fetuses half was obstructed and the remainder served as controls. The doe and fetuses were sacrificed on day 30 of gestation (full term 31 to 32 days) and the fetal bladders were removed. Bladders that had doubled in weight from the average bladder weight of the control littermates were deemed sufficiently obstructed. Hematoxylin and eosin staining was performed and bladder strip response to 32 Hz. field stimulation, 200 microM. bethanechol and 200 mM. potassium chloride was measured.

RESULTS

Average body weight did not differ between the control and obstructed fetuses, indicating that surgery did not hinder fetal development. Hematoxylin and eosin staining confirmed smooth muscle cell hypertrophy and increased connective tissue in the obstructed bladders. Obstructed bladder strips responded significantly less to field stimulation, and significantly more to bethanechol and potassium chloride (mean plus or minus standard deviation 5.18 +/- 1.52, 6.29 +/- 1.3 and 10.15 +/- 2.18 x force per/100 mg. tissue, respectively)than control bladder strips (9.0 +/- 1.19, 3.5 +/- 0.46 and 6.16 +/- 1.33 x force per/100 mg. tissue, respectively) suggesting that denervation supersensitivity may have resulted from obstruction.

CONCLUSIONS

Partial outlet obstruction of the fetal rabbit bladder results in bladder hypertrophy and dysfunction but these changes are markedly different from those in the adult rabbit. Since rabbit fetal development is delayed compared to human fetal development, this model can be used to assess the consequences of posterior urethral valves.

Proximal urinary diversion in the management of posterior urethral valves: is it necessary?

PURPOSE

In infants with posterior urethral valves in whom renal function fails to normalize following decompression of the lower urinary tract supravesical urinary diversion is customarily recommended for presumed concomitant ureterovesical junction obstruction. We determined the true incidence of fixed or permanent ureterovesical junction obstruction and the renal prognosis for infants treated with proximal urinary diversion.

MATERIALS AND METHODS

We evaluated 26 patients with posterior urethral valves treated with supravesical urinary diversion. Mean gestational age at birth was 35 weeks (range 27 to 40). After initial decompression via an indwelling catheter for a median of 7 days (range 4 to 18) persistently high serum creatinine was present (median 2.5 mg./dl., range 1.9 to 3.5). One month after proximal urinary diversion median creatinine was 1.3 mg./dl. (range 0.5 to 2.8). At 1 year, median nadir creatinine was 1.0 mg./dl. (range 0.3 to 2.5). At reconstruction a Whitaker test in all 26 patients (52 renal units) demonstrated fixed ureterovesical junction obstruction in 2 units (4%).

RESULTS

Renal biopsy in 44 of the 52 renal units (85%) revealed renal dysplasia. At a median followup of 9 years (range 1 to 14) end stage renal disease developed in 11 patients (42%).

CONCLUSIONS

In neonates with posterior urethral valves who undergo proximal urinary diversion fixed ureterovesical junction obstruction is rare, renal biopsy invariably demonstrates areas of renal dysplasia and end stage renal disease frequently develops despite proximal diversion. These findings lead us to question the necessity of supravesical urinary diversion.