Transurethral injection therapy with carbon-coated beads (Durasphere®) for treatment of recurrent pyelonephritis in kidney transplant patients with vesico-ureteral reflux to the allograft

Urologic issues in pediatric transplant recipients

The limited supply of kidneys for pediatric transplantation leads to a large number of children in waiting transplant list. These patients have to be properly evaluated and prepared before organ transplantation to increase its success. The aim of this review is focus on urologic issues of pediatric kidney transplants such as preoperative evaluation and urinary tract abnormalities correction, surgical technique, and postoperative complications. All children that are candidates for kidney transplantation should be submitted to abdominal ultrasound. If bladder dysfunction is suspected, a more detailed evaluation is mandatory, including a voiding cystourethrography and urodynamic study. Patients with a poor bladder capacity and compliance will require bladder augmentation. Whenever possible the native ureter is recommended for that. Regarding kidney transplantation, recipient surgery can be safely performed through an extraperitoneal access, even in children weighting less than 10 kilograms. It allows adequate access to iliac vessels, aorta and vena cava. Graft survival continued to improve over the past decade and it is around 80% in 5 years. Postoperative complications such as urinary fistula may occur in less than 5% of cases, while vascular complications are reported in 1% to 2% of cases.

Durasphere® EXP: a non-biodegradable agent for treatment of primary Vesico-Ureteral reflux in children

Introduction:

Durasphere^® EXP (DEXP) is a compound of biocompatible and non--biodegradable particles of zirconium oxide covered with pyrolytic carbon. The aim of this study is to evaluate the durability of off-label use of DEXP in the treatment of primary vesicoureteral reflux in children.

Materials and Methods:

Patients who underwent subureteric injection of DEXP for the correction of primary VUR were retrospectively reviewed. Patients aged >18 years as well as those who had grade-I or -V VUR, anatomic abnormalities (duplicated system, hutch diverticulum), neurogenic bladder or treatment refractory voiding dysfunction were excluded. Radiologic success was defined as the resolution of VUR at the 3rd month control. Success was radiographically evaluated at the end of the first year.

Results:

Thirty-eight patients (9 boys, 29 girls; mean age, 6.3±2.7 years) formed the study cohort. Forty-six renal units received DEXP (grade II: 22; grade III: 18; grade IV: 6). Mean volume per ureteric orifice to obtain the mound was 0.70±0.16mL. First con- trol VCUG was done after 3 months in all patients. After the first VCUG, 6 patients had VUR recurrence. Short-term radiologic success of DEXP was 84.2%. Rate of radiologic success at the end of the first year was 69.4% (25/32). Lower age (p:0.006) and lower amount of injected material (p:0.05) were associated with higher success rates at the end of 1 year.

Conclusion:

This is the first study to assess the outcomes of DEXP for treatment of primary VUR in children. After 1 year of follow-up, DEXP had a 69.4% success rate.

Renal function outcomes in pediatric patients with symptomatic reflux into the transplanted kidney treated with redo ureteroneocystostomy

INTRODUCTION

Asymptomatic post-renal transplant reflux is common but only 5-10% patients are diagnosed with vesico-ureteral reflux in the setting of post-transplant febrile urinary tract infections, requiring redo ureteroneocystostomy (redo-UNC). Here we report the renal function outcomes of 37 such patients, stratified by lower urinary tract (LUT) status.

OBJECTIVE

We hypothesized that those with pre-transplant LUT dysfunction would have lower glomerular filtration rate (GFR) on follow-up.

STUDY DESIGN

Using procedure codes, 37 patients who underwent renal transplant followed by redo-UNC for transplant reflux at our institution between 1991 and 2014 were identified. Patient characteristics and GFR levels from four different time points were recorded. Comparisons were made between those with and without LUT dysfunction, using Fisher's exact, Wilcoxon rank sum, or signed-rank tests. Generalized estimating equations were constructed to account for the clustered nature of GFR within each LUT group and to assess their change over time.

RESULTS

Twelve patients (32%) had pre-transplant LUT dysfunction. The proportion of males in this group was significantly higher (75% vs. 32%, p = 0.032), and there was no statistical difference towards presenting earlier with post-transplant reflux (1.4 vs. 2.3 years, p = 0.087). After an average of 4.9 years, the median GFRs were similar between the two groups (53 mg/dL vs. 58 mg/dL, p = 0.936). There was no significant difference in GFR at this last follow-up time point in patients with and without LUT dysfunction.

DISCUSSION

Vesicoureteral reflux in the setting of renal transplantation is common and doesn't often require repair. In our series, we found that those with LUT dysfunction did not present statistically sooner with symptomatic transplant reflux. Longer-term follow-up did show a decline in GFR but did not reveal a difference in GFR in patients' with and without LUT dysfunction.

CONCLUSIONS

Pediatric post-transplant GFR after open redo ureteral reimplant decreases over time in similar fashion in patients with symptomatic reflux regardless of whether they have LUT dysfunction or normal anatomy. Vigilance should apply to the recognition, treatment, and follow-up of all symptomatic transplant reflux regardless of LUT status.

Recurrent urinary tract infections in kidney transplant recipients

Urinary tract infections (UTIs) are the most common infectious complication after kidney transplantation (KT). Recurrent UTIs after KT can contribute to increased morbidity and may also be associated with graft loss and mortality. Though several risk factors like female gender, diabetes mellitus, presence of ureteric stents, native kidney disease with urological malformations and re-transplantation have been associated with recurrent UTIs after KT, vesicoureteric reflux appears to be a unique risk factor in this patient population. The emergence of drug-resistant pathogens as causative agents for post-transplant recurrent UTIs poses a significant therapeutic challenge. The use of pathogen-specific antibiotic therapy guided by culture and sensitivity data is warranted. The optimal duration of antimicrobial therapy for recurrent UTIs in renal transplant recipients remains uncertain.