Posterior urethral valve: Prognostic factors and renal outcome

Comparing Estimated and Measured Glomerular Filtration Rate in Children with Posterior Urethral Valve

Background

Posterior urethral valve (PUV) is obstructive uropathy that may lead to chronic kidney disease (CKD) and end-stage renal disease (ESRD) in children. Glomerular filtration rate (GFR) measurement remains the gold standard for renal function measurement. However, due to its less availability and cumbersome, it is not commonly used, and GFR is estimated utilizing various endogenous filtration markers.

Objective

This study includes pediatric patients with PUV. We aimed to compare the measured GFR (mGFR) with various creatinine-based estimated GFR methods (eGFR).

Materials and Methods

A single-center retrospective study included 62 treated cases of PUV, postvalve fulguration. The mGFR measured by 99mTc-diethylenetriaminepentaacetate in vitro method and compared with eight eGFR (Schwartz, Cockcroft-Gault [CG], Counahan-Barratt [CB], CKD Epidemiology Collaboration [CKD-EPI], full-age spectrum [FAS] age, FAS height (FAS Ht), Schwartz-Lyon [SL], and Ht independent). Patients were subdivided into different CKD grades and compared with various eGFR.

Discussion

PUV is a common cause of CKD in children and needs special consideration as there is growth retardation associated with it. It decreases creatinine production and thus fallacies in eGFR measurement. There is a requisite to identify and closely monitor the subset of patients with baseline decreased renal function and therefore at risk of developing ESRD.

Results

A total of 62 patients were included. Mean age and serum creatinine levels were 8.02 ± 5.53 years and 1.15 ± 0.95 mg/dl (range: 0.4-4.5), respectively. The mean mGFR was 61.6 ± 31.80 mL/min/1.73 m2 and a positive variable correlation was 0.46-0.77 between mGFR and eGFR. Based on mGFR, there were 14 (22.6%), 21 (33.8%), 13 (20.9%), 9 (14.5%), and 5 (8.1%) patients in Grades I-V, respectively. The correct classification of the CKD grades was noted in 25 (40.3%), 16 (25.8%), 32 (51.6%), 16 (25.8%), 25 (40.3%), 27 (43.5%), 26 (41.9%), and 28 (45.2%) patients by Schwartz, CG, CB, CKD-EPI, FAS age, FAS Ht, SL, and Ht-independent equation. The eGFR overestimates GFR at the lower level and underestimates at higher levels.

Conclusion

Our results confirm the considerable limitations of various creatinine-based clearance methods for estimating actual GFR. The creatinine clearance-based eGFR should not replace the measurement of the GFR. An initial measure of the mGFR followed by serial follow-up with the eGFR equation may be done. The most accurate eGFR equations are CB for Grade II, SL or Ht independent for Grade III, FAS age for Grade IV, and SL for Grade V CKD.

Does Early Upper Tract Diversion and Delayed Undiversion in Megaureters Secondary to Severe Posterior Urethral Valves Lead to Better Renal Outcomes?

Background

There are conflicting reports for the management of severe posterior urethral valve (PUV) after ablation. The primary objective was to assess the renal outcomes using the estimated glomerular filtration rate (eGFR) and secondary outcomes in severe PUVs who underwent early partially diverting reduction ureterostomy (PDRU) and a delayed undiversion protocol.

Materials and Methods

This 10-year retrospective study reviewed the records of 1094 boys with PUV, where severe PUV cases were treated with early PDRU (324 surgeries). We then analyzed those patients who completed the early diversion and delayed undiversion protocol. The long-term renal outcomes using eGFR and antero-posterior diameter (APD) were compared at various time points using appropriate statistical methods.

Results

Of the 171 severe PUV patients who underwent PDRU, 31 completed undiversion and 26 (47 renal units) were analyzed after exclusions. The mean age (standard deviation) at presentation was 1.46 ± 4.1 months. Thirty-two units were refluxing and 15 were nonrefluxing megaureters. PDRU was closed at a mean age of 3.9 years and had a mean duration of follow-up of 6.4 years. The mean eGFR increased from a minimum of 10.78 ± 10.25 at baseline and remained stable at 28.69 ± 18.89 after closure of both stoma. Similarly, mean APD decreased from 12.07 ± 6.79 at the diagnosis to 7.00 ± 6.20. Three patients (3 renal units) required revision of the stoma for stenosis and 1 patient had a parastomal hernia that was repaired at the time of undiversion.

Conclusions

In severe PUVs, early PDRU with delayed undiversion is a reliable surgical option that may ensure better renal outcomes in the long-term. Nonrefluxing renal units recover better than the refluxing. APD measurements also are shown to improve favorably.

Association of Renal Glomerular and Tubular Function With Renal Outcome in Patients With Posterior Urethral Valves

OBJECTIVE

To analyze renal glomerular and tubular function and their association in patients operated for posterior urethral valves and to prognosticate the risk for end-stage kidney disease (ESKD) METHODS: Sixty-three previously treated patients were evaluated for renal function during 1987-1991. The patients' age at evaluation was 11 years (range 2-24). Glomerular function was assessed by measuring glomerular filtration rate (GFR) and urine albumin excretion. Tubular function was determined by measuring urine concentration capacity and excretion of electrolytes (Na, K, Cl, Ca, P, Mg) and β-2-microglobulin. Additionally, the prevalence of hypertension and serum parathyroid hormone and aldosterone values were registered. Tubular function was compared with GFR and the risk of developing ESKD before November 2018.

RESULTS

Twenty of the study patients (32%) had decreased GFR. In addition, 19% had proteinuria and 56% were hypertensive. Those without proteinuria or hypertension had better GFR values (P < .01 for both). There was a significant correlation between GFR and all the tubular function (P < .05) variables (except excretion of chloride) measured. Compared to the patients with favorable renal outcome, the patients (n = 10) who later developed ESKD had significantly (P < .01) lower GFR and reduced urinary excretion of all measured electrolytes except calcium. Consistently, urine β-2 microglobulin and serum parathyroid hormone and aldosterone values were significantly higher in the patients who developed ESKD (P ≤ .01).

CONCLUSION

Both glomerular and tubular function decline was common and several parameters were likely to predict ESKD in posterior urethral valves patients.

Role of Urinary Transforming Growth Factor Beta-B1 and Monocyte Chemotactic Protein-1 as Prognostic Biomarkers in Posterior Urethral Valve

Background:

Posterior Urethral Valves (PUV) are the most common cause of congenital LUT obstruction in males. Biomarkers of glomerular or tubular injury may be of particular value in predicting the need for surgical intervention or in tracing progression of chronic kidney disease. Measurement of biomarker in urine is relatively easy.

Aim:

To evaluate the changes in values of urinary Transforming Growth Factor Beta 1(TGF-B1) and Monocyte Chemotactic Protein (MCP-1) before and after valve ablation and its prognostic value in Posterior urethral valve.

Material and Method:

This prospective study was conducted from September 2016 to August 2018. The study group included 20 consecutive male babies with the diagnosis of PUV treated and followed up versus equal numbers of age matched control without any renal or urinary tract disease. Pre-operative urine samples were collected in Operative room. Cystoscopy and valve ablation was done. Follow up was done clinically by urinary stream and radiologically with VCUG. Follow-up was planned at 1 month, 3 months and 6 months following cystoscopic valve ablation. All collected urine samples were centrifuged at 10,000 rpm for 20 minutes. Supernatant was collected and two divided aliquots were stored at -200c to be thawed on the day of assay. Optical density of each well was recorded at 450 nm and 540 nm A p-value of <0.05 was considered to be statistically significant.

Result and Discussion:

Out of 20 cases of PUV, 14 (70%) cases were 1st born males of their family. The median age at the time of valve ablation in PUV cases was 2.5 (1.20-3.87) years.. Most common symptoms are fever and UTI. The preoperative median serum creatinine level was 1.65 mg/dl(1.22-2.42) pre-ablation, and fall significantly after ablation. Median eGFR level (calculated) was 25.635 (16.38-35.40) and after 6 months was 71.490 (45.44-96.93). Preoperative median MCP1 in PUV cases was 147.2 (82.8-512.5) and significant difference was also found in 1st, 3rd and 6th months after surgery (p<0.001, p=0.004 and p=0.002).Preoperative median TGF-B1 level was 197.8 pg/ml (79.9-386.4). There was no statistically significant change in TGF-B1 level at preoperative to 1 month and preop to 3 months after surgery but at 6 months after surgery the median TGF-B1 level significantly decreased as compared with preoperative TGF-B1 level.

Conclusion:

TGF β1 and MCP1 can be considered as prognostic urinary biomarkers in patients of PUV and can be used to specify and counsel patient's attendant regarding possibility of ESRD and need for further intervention.

Serum creatinine levels in cases of posterior urethral valve: 29 years experience of a pediatric urology reference center

OBJECTIVES

The aim of this retrospective study is to describe the importance of serum creatinine levels for the long-term renal outcome in cases of posterior urethral valve.

METHODS

Records of 94 patients who underwent cystoscopic valve ablation were evaluated retrospectively. Demographic variables, radiologic findings, and serum creatinine levels were recorded. Patients were grouped according to the serum creatinine levels in the first month of life. Twenty-four patients' serum creatinine levels were found to be above 1 mg/dL in group 1 and ≤1 mg/dL in 70 patients in group 2.

RESULTS

The initial findings of 74 patients were as follows: pyelonephritis in 24 (32.43%) patients, hydronephrosis in 20 (27.02%), and inability to urinate in 18 (24.32%). Prenatal hydronephrosis was present in 36 cases (38.29%). Of the 92 voiding cystograms, 53.26% had findings that included vesicoureteral reflux. The mean serum creatinine levels of the patients in group 1 increased above 1 mg/dL in the 2nd year, the significant difference between the two groups lasted up to 7 years of age, and no significant difference was observed at the age of 7. The mean serum creatinine levels of the patients in group 2 were observed to increase above 1 mg/dL by the 10th year.

CONCLUSIONS

In patients with posterior urethral valves, nadir creatinine, especially higher than 1 mg/dL, should be considered as high risk for end-stage renal disease. Therefore, clinicians should improve awareness about early detection and treatment of posterior urethral valves, and these patients should be monitored as early as possible for the risk of chronic kidney disease.

Comparison of early neonatal valve ablation with vesicostomy in patient with posterior urethral valve

BACKGROUND

To compare the results of final renal function by two methods of treatment in patients diagnosed as posterior urethral valve (PUV) (valve ablation vs. vesicostomy).

MATERIALS AND METHODS

Fifty-four boys diagnosed with PUV participated in this study. They were divided into top two groups. Thirty-one of the total were treated with primary valve fulguration (Group 1) and 23 were treated with vesicostomy (Group 2). One-year-creatinine level and glomerular filtration rate (GFR) were measured. Also, they were taken ultrasonography detecting hydronephrosis. Data analysed in IBM SPSS21 with t-test and Chi-square test. Presented with 95% of confidence intervals.

RESULTS

Fifty-four boys diagnosed with PUV participated in this study. The mean age of patients in Group 1 was 3.8 ± 1.48 days and Group 2 was 4.7 ± 1.85 days. One-year Cr level was 1.57 ± 1.45 in Group 1 and 1.57 ± 1.45 in Group 2 which was not statistically significant (P < 0.8). Also 1-year GFR level was 31.1 ± 4.4 in Group 1 and 33 ± 4.7% in Group 2 (P < 0.10/23) in Group 2 (43.47%) had severe hydronephrosis and 14/31 (45.16%) in Group 1 had severe hydronephrosis. Graded ultrasound results were not significantly different (P = 0.24).

CONCLUSION

The results showed no significant difference. Vesicostomy might be a more favourable method due to less complication and follow-up in early neonatal life. Hence, the condition of the patients and decision of the surgeon are effective parameters in choosing an optimal method in patients diagnosed with PUV.

Study of prognostic significance of antenatal ultrasonography and renin angiotensin system activation in predicting disease severity in posterior urethral valves

Aims:

Study on prognostic significance of antenatal ultrasonography and renin angiotensin system activation in predicting disease severity in posterior urethral valves.

Materials and Methods:

Antenatally diagnosed hydronephrosis patients were included. Postnatally, they were divided into two groups, posterior urethral valve (PUV) and non-PUV. The studied parameters were: Gestational age at detection, surgical intervention, ultrasound findings, cord blood and follow up plasma renin activity (PRA) values, vesico-ureteric reflux (VUR), renal scars, and glomerular filtration rate (GFR).

Results:

A total of 25 patients were included, 10 PUV and 15 non-PUV. All infants with PUV underwent primary valve incision. GFR was less than 60 ml/min/1.73 m² body surface area in 4 patients at last follow-up. Keyhole sign, oligoamnios, absent bladder cycling, and cortical cysts were not consistent findings on antenatal ultrasound in PUV. Cord blood PRA was significantly higher (P < 0.0001) in PUV compared to non-PUV patients. Gestational age at detection of hydronephrosis, cortical cysts, bladder wall thickness, and amniotic fluid index were not significantly correlated with GFR while PRA could differentiate between poor and better prognosis cases with PUV.

Conclusions:

Ultrasound was neither uniformly useful in diagnosing PUV antenatally, nor differentiating it from cases with non-PUV hydronephrosis. In congenital hydronephrosis, cord blood PRA was significantly higher in cases with PUV compared to non-PUV cases and fell significantly after valve ablation. Cord blood PRA could distinguish between poor and better prognosis cases with PUV.