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Volume: 18 Issue: 1 January 2020 - Supplement - 1

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Lower Urinary Tract Dysfunction and Pediatric Renal Transplant

Objectives: Lower urinary tract abnormalities have been considered to be contraindications for renal transplant. However, advancements in diagnosis and treatment in this area have allowed renal transplant as a treatment choice in selected cases. We evaluated clinical outcomes of pediatric renal transplant in patients with lower urinary tract dysfunction.

Materials and Methods: We retrospectively evaluated data from 165 pediatric renal transplant patients, and data were compared between patients with and without lower urinary tract dysfunction. Patient demographics, cause of chronic renal failure, acute rejection episodes, and graft loss were included in our analyses.

Results: Seventeen patients had lower urinary tract dysfunction, and the remaining 148 patients had functional lower urinary tracts. Patients with lower urinary tract dysfunction were younger than the other patient group at diagnosis of chronic renal failure. The mean follow-up after renal transplant in the 2groups was similar. Differences with regard to donor type, immunosuppressive treatment, and acute rejection episodes were not significant between the 2 groups. Eight patients had lost their grafts during follow-up; however, only 1of these patients was in the lower urinary tract dysfunction group. Graft loss rate was similar between the groups.

Conclusions: Pediatric patients with lower urinary tract dysfunction had similar graft outcomes versus other pediatric renal transplant patients. Careful evaluation and preparation of the lower urinary tract are important factors for renal transplant success.


Key words : Bladder augmentation, Kidney transplantation, Neurogenic bladder

Introduction

Congenital anomalies of the kidney and urinary tract are the most common causes of renal failure. In pediatric patients with end-stage renal failure, 20% to 30% have lower urinary tract dysfunction.1 Lower urinary tract abnormalities have been recently considered to be contraindications for renal transplant.

Lower urinary tract abnormalities involve high risks after transplant for renal graft function, urinary tract complications, and infections. For a successful transplant, a bladder must have adequate capacity, good compliance, and efficient voluntary emptying.2 Bladder reconstruction or rehabilitation can be curative for these patients. Advancements in diagnosis and treatment in this area have allowed renal transplant to be a treatment choice in selected cases.

In this study, we evaluated clinical outcomes of renal transplant in pediatric patients with lower urinary tract dysfunction.

Materials and Methods

We retrospectively evaluated data from 165 pediatric renal transplant patients (73 female and 92 male patients). For our analyses, we divided patients into those with and without lower urinary tract dysfunction. Patient demographics, cause of chronic renal failure, radiologic imaging results, urodynamic testing results, age at time of transplant, donor type, immunosuppressive treatment, serum creatinine level, glomerular filtration rate, infection episodes, acute rejection episodes, and graft loss were recorded.

All patients underwent urinary tract ultrasono­graphy and radiographic voiding cystoureterography before transplant. Urinary tract ultrasonography was performed in prone position and included examination of size, shape, presence of hydroneph­rosis, scars and parenchymal thickness, and structure of the kidney and urinary tract. The bladder was examined for capacity, wall structure, and thickness. Voiding cystoureterography was con­ducted with the use of a digital screening unit for vesicoureteral reflux existence and bladder and urinary tract structure. Urodynamic tests were performed on patients with suspicion of lower urinary tract dysfunction.

Bladder reconstruction was performed generally 3 months before transplant. Some patients with recent bladder reconstruction before end-stage renal failure were also included in the study.

Results

Congenital anomalies of the kidney and urinary tract and glomerulonephritis were the most common cause of renal failure in our study group. Seventeen patients (10.3%) had lower urinary tract dysfunction, and the remaining 148 patients had a functional lower urinary tract (Table 1). In the group with lower urinary tract dysfunction, 7 patients had posturethral valve, 8 patients had neurogenic bladder due to different causes (prune belly syndrome, Bardet Biedl syndrome, etc.), 1 patient had nonneurogenic neurogenic bladder, and 1 patient had vesical hypoplasia.

Patients with lower urinary tract dysfunction were younger than patients in the other group (3.73 ± 2.42 vs 7.84 ± 5.19 y; P = .002) at time of diagnosis of chronic renal failure.

Three patients with lower urinary tract dysfunction underwent ileo bladder surgery before transplant. Two patients with recent bladder reconstruction underwent bladder augmentation before end-stage renal failure. Other patients with lower urinary tract dysfunction were transplanted with recommendation for frequent voiding.

Immunosuppressive treatment consisted of calcineurin inhibitors (cyclosporine or tacrolimus), sirolimus, or everolimus, mycophenolate mofetil, and prednisolone. Of total patients, 127 received living-related donor allografts and 38 received grafts from deceased donors. Donor type and immunosup­pressive treatment were not significantly different between the 2 groups. Mean follow-up time after renal transplant (58.00 ± 24.88 vs 78.29 ± 52.73 mo; P = .136) was similar between groups.

Urinary tract infections rate was significantly higher in the lower urinary tract dysfunction group (2.47 ± 1.57 vs 1.20 ± 0.37 infection episodes per patient; P = .044).

Acute rejection episodes between groups were not significantly different: glomerular filtration rate at year 5 of follow-up was similar between the 2 groups (53.85 ± 37.36 vs 63.40 ± 32.57 mL/min; P = .492). Eight patients (4.84%) had graft loss during the 5-year follow-up period, but only 1 of these patients was in the lower urinary tract dysfunction group. Graft loss rate was similar between the 2 groups (P > .05) (Table 2).

Discussion

Patients with lower urinary tract dysfunction are not preferred candidates for renal transplant. The high risk of graft loss can halt the chance of transplant in these patients.

A functioning bladder is key to a successful transplant for patients with lower urinary tract dysfunction. Urine storage of a functioning bladder must be done at low bladder pressure without any urine leak, and the bladder must be able to completely empty without any residue.3,4 Preoperative evalu­ations must be done carefully to avoid posttransplant allograft injury. Bladder reconstruction in selected cases can allow a chance for transplant for these patients.

Although patients may have a normal functioning bladder, urinary tract infections are common after renal transplant. Recurrent urinary tract infections are related with worse outcomes in all patients.5 Patients with lower urinary tract dysfunction, despite having undergone bladder reconstruction, tend to have considerably more urinary tract infections than patients without lower urinary tract dysfunction.6 The rate of urinary tract infections was significantly higher in our patients with lower urinary tract dysfunction. Rates were higher during the first year posttransplant and then decreased. This may be related to improved bladder function with time and reduction of immunosuppressive treatment. Recurrent urinary tract infections were not associated with worse graft function in our study group.

Five-year graft survival has been shown to be between 58% and 88.9%. Some studies have demonstrated that graft survival with lower urinary tract dysfunction was better with a graft from a living donor than from a deceased donor. Some studies have shown that transplant recipients with lower urinary tract dysfunction had higher incidence of rejection episodes; however, these findings have not been confirmed.3,7 Incidence of acute rejection episodes, glomerular filtration rate at year 5 posttransplant, and graft loss rate at year 5 posttransplant were similar in patients with and without lower urinary tract dysfunction.

We demonstrated that pediatric patients with lower urinary tract dysfunction had graft outcomes similar to other pediatric renal transplant recipients. Careful evaluation and preparation of lower urinary tract are important factors for success with renal transplant.


References:

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Volume : 18
Issue : 1
Pages : 41 - 43
DOI : 10.6002/ect.TOND-TDTD2019.O21


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From the Departments of 1Pediatric Nephrology, 2General Surgery, and 3Radiology, Başkent University, Ankara, Turkey
Acknowledgements: The authors have no sources of funding for this study and have no conflicts of interest to declare.
Corresponding author: Kaan Gulleroglu, Baskent University Pediatric Nephrology Department, Temel Kuğuluoğlu C. No: 24 K: 3, Bahcelievler-Cankaya 06490, Ankara, Turkey
Phone: +90 312 2234936
E-mail: kaangulleroglu@yahoo.com