The Role of Urodynamics in the Pre-transplant Evaluation of Renal Transplant

Posterior urethral valves and kidney transplantation: Identifying opportunities for improvement

BACKGROUND

Posterior urethral valves (PUV) represents a heterogenous spectrum in which guidelines for management are lacking particularly for those patients facing end-stage kidney disease and transplant. In this study we aim to 1) evaluate our long term PUV pediatric transplant outcomes compared to those without lower urinary tract dysfunction and 2) assess our PUV cohort for trends in bladder management and evaluate outcomes to inform development of institutional guidelines.

MATERIALS AND METHODS

A retrospective cohort analysis of all patients with a diagnosis of PUV who underwent kidney transplant from 2000 to 2023 was completed. A matched cohort of patients without lower urinary tract dysfunction was identified for comparison of graft function. Charts of PUV patients were reviewed for both sociodemographic and clinical variables. Patients were classified by bladder management at the time of transplantation into three separate groups for analysis: voiding, clean intermittent catheterization, and incontinent diversion. Primary outcomes of interest were eGFR, graft failure, and UTIs post-transplant.

RESULTS

45 patients met inclusion criteria. 69% were on dialysis prior to transplant. 51% of grafts were from a deceased donor. Bladder management consisted of voiding (62%), CIC (4 via urethra, 10 via channel) (31%), and incontinent diversion (7%). 20% underwent augmentation cystoplasty (5 = ureter, 2 = gastric, 1 = colon, and 1 = ileum) prior to or at the time of transplant. Median follow up duration was 5.4 years (3.0, 10.8). Patients on CIC had higher rates of UTI; however, we found no significant difference in graft function outcomes (eGFR, graft failure) between bladder management groups or year of transplant. VUR in the transplant kidney was associated with vesicostomy (p = 0.028). 2 of 2 gastric augments developed malignancy, one of which was cause of death. Graft failure rate was 22% in both the PUV group and matched cohort, with median interval times to failure of 6.7 years and 3.7 years, respectively (p = 0.71). There were no differences in eGFR at follow-up time points between the PUV and matched cohort.

CONCLUSIONS

Patients with PUV represent a spectrum of disease with heterogeneous management before and after kidney transplant. Overall, graft function outcomes were similar when compared to matched cohort without lower urinary tract dysfunction. Patients on CIC had higher rates of UTI but without impact on graft function. Gastric augmentation cystoplasty should be avoided given risk for malignancy. Guidelines to standardize evaluation and management would be helpful for patient care and outcomes.

Children Are Not Small Adults: Similarities and Differences in Renal Transplantation Between Adults and Pediatrics

Kidney transplantation is the treatment of choice for all patients with end-stage kidney disease, including pediatric patients. Graft survival in pediatrics was lagging behind adults, but now is comparable with the adult cohort. Although many of the protocols have been adopted from adults, there are issues unique to pediatrics that one should be aware of to take care of this population. These issues include recipient size consideration, increased incidence of viral infections, problems related to growth, common occurrence of underlying urological issues, and psychosocial issues. This article addresses the similarities and differences in renal transplantation, from preparing a patient for transplant, the transplant process, to post-transplant complications.

Diagnostic and therapeutic management of vesico-ureteral reflux in pediatric kidney transplantation-Results of an online survey on behalf of the European Society for Paediatric Nephrology

BACKGROUND

Vesico-ureteral reflux (VUR) is considered to be a risk factor for recurrent febrile urinary tract infections and impaired renal transplant survival.

METHODS

An online survey supported by the European Society for Paediatric Nephrology was designed to evaluate current management strategies of VUR in native and transplanted kidneys of recipients aged <18 years.

RESULTS

Seventy-three pediatric transplant centers from 32 countries contributed to the survey. All centers performed urological evaluation prior to pediatric kidney transplantation (KTx) with subsequent interdisciplinary discussion. Screening for VUR in native kidneys (30% in all, 70% in selected patients) led to surgical intervention in 78% (11% in all, 89% in selected patients) with a decided preference of endoscopic intervention over ureterocystoneostomy. Following KTx, continuous antibiotic prophylaxis was applied in 65% of the patients and screening for allograft VUR performed in 93% of selected patients. The main management strategies of symptomatic allograft VUR were continuous antibiotic prophylaxis (83%) and surgical treatment (74%) (endoscopic intervention 55%, redo ureterocystoneostomy 26%).

CONCLUSIONS

This survey demonstrates the high variability in the management of VUR in pediatric KTx recipients, points to knowledge gaps, and might serve as a starting point for improving the care for patients with VUR in native and transplanted kidneys.

Factors associated with low-compliance bladder in end-stage renal disease patients and development of a clinical prediction model for urodynamic evaluation: the DUDi score

OBJECTIVES

To investigate factors associated with low-compliance bladders (LCB) in pretransplant patients with end-stage renal disease (ESRD) and develop a clinical prediction model for urodynamic studies.

METHODS

This study was a prospective cohort study. Patients with ESRD on the renal transplantation waiting list were recruited and underwent the urodynamic study. Demographics data, predictor factors related to the bladder compliance such as underlying disease of the lower urinary tract disease (LUTD), duration of urine < 250 mL/day, type and duration of renal replacement therapy (RRT), urine volume per day and urodynamic study information were collected. Univariable and multivariable logistic regression models were used to assess the independence of explanatory factors, then we developed the clinical prediction model.

RESULTS

One hundred fifty-two patients participated in the study: 94 patients in the normal bladder group and 58 patients in LCB group. Demographic data were not significantly different between the two groups, except diabetes. Cystometric capacity, detrusor pressure, compliance were significantly different. From the univariate analysis, DM status, duration of RRT, and passing < 100 mL of urine per day were related to LCB. We named the prediction model, the DUDi score based on the predictors (Duration of RRT, Urine volume/day, Diabetes). Higher scores predicted a higher risk of low-compliance bladder [P value = 0.464 according to the Hosmer-Lemeshow test, and the AUC was 0.87 (95% CI 0.81-0.92)].

CONCLUSIONS

Our clinical prediction model is easy to use and provides a high predictive value that is appropriate for patients who have no known LUTD to identify low-compliance bladder. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION FOR PROSPECTIVELY REGISTERED TRIALS: This study was approved by the Thai Clinical Trials Registry Committee on 09 February 2021. The TCTR identification number is TCTR20210209006.

Spectrum of lower urinary tract symptoms after renal transplant among adult non-urologic anuric patients and their management in a tertiary care center

INTRODUCTION

Lower urinary tract symptoms (LUTS) in a post-transplant patient can lead to several complications including recurrent UTI and deterioration of the graft kidney function. The aim of this study is to investigate the spectrum of LUTS, possible complications resulting from it and its management after renal transplant in pre-transplant anuric patients operated in our tertiary care institute.

MATERIALS AND METHODS

It was a retro-prospective observational study done on post-transplant patients operated in this institute from December 2016 to December 2020. Among 165 patients operated during this period 50 male and 21 female patients were finally included in this study. Urinary symptoms were evaluated using the IPSS Questionnaire. Pre and post-surgery Uroflowmetry findings were compared. Urodynamic assessment was done at least 6 months after surgery to determine the cause behind such symptoms. The data was analyzed with the help of standard statistical methods and SPSS 21 software.

RESULTS

The most common LUTS among the post renal transplant patients were frequency and nocturia. There was a marked improvement in voided volume and urinary flow in most of the patients. In 11 male and 7 female patients LUTS symptoms were moderate to severe and were seldom associated with recurrent UTI and graft compromise. A cautious approach in these patients helped in early diagnosis of the etiology behind LUTS, which were treated accordingly.

CONCLUSION

LUTS should be carefully evaluated before renal transplantation. Postoperatively moderate to severe LUTS symptoms should be thoroughly investigated so that graft compromise and related complications can be prevented by early intervention.

On-table urodynamic with ureteric occlusion: A resource for measuring bladder capacity and compliance in the management of patients with gross vesico-ureteric reflux

AIM

To describe a technique for on-table urodynamic with ureteric occlusion (OUUO) and present a case series comparing bladder capacity and pressure measurements performed with and without ureteric occlusion in patients with gross vesico-ureteric reflux (grade ≥ IV VUR) to highlight the clinical utility.

METHODS

We performed OUUO in seven patients who were being considered for surgical management of VUR and/or nephro-ureterectomy. We occluded the refluxing ureters using hysterosalpingogram catheters (HSG, single lumen 5.5 Fr catheter with 1.5 ml balloon), guidewires, and rigid cystoscope. A 6 Fr dual-lumen urodynamic (UD) catheter is then inserted into the bladder to perform OUUO. Bladder capacity and Compliance (C = ∆bladder volume/∆detrusor pressure) are recorded and compared with values obtained at standard UD (without ureteric occlusion).

RESULTS

The age range of the seven patients was 2.0-15.5 years. The etiology for the gross VUR were posterior urethral valve (PUV) and neuropathic. The bladder capacity and compliance finding between UD and OUUO findings were comparable in five patients. However, there was a clinically significant difference in bladder capacity (20%-50% decrease) and compliance (50%-90%) between UD and OUUO findings in two out of seven patients.

CONCLUSION

In the presence of gross VUR, OUUO allows for a potentially more accurate assessment of bladder capacity and compliance. OUUO should be considered when planning ureteric opening bulking/reimplantation and nephro-ureterectomy.

Are All Stent Bearers Equal? Ureteral Stent Symptoms in Kidney Transplant Patients: A Case-Control Prospective Study

Purpose: The aim of this study is to conduct a prospective, controlled single-center study to determine the prevalence and types of ureteral stent symptoms in kidney transplant (KTx) recipients and compare them with nontransplant subjects. Materials and Methods: From December 2012 to June 2019, a total of 102 patients having undergone a KTx and Double-J stent (DJS) placement and 88 patients having undergone endourological lithotripsy and DJS placement were enrolled. The Ureteral Stent Symptom Questionnaire (USSQ) was administered to patients with a median of 25 (KTx) and 31 (urolithiasis) days after stent placement. USSQ scores were used to compare symptoms between the two groups. Results: Of the 190 patients enrolled, 88 belonged to the lithotripsy group (control group) and 102 to the KTx recipients' group. Mean score for urinary symptoms was 21.42 for KTx patients vs 27.53 for control patients with statistical significance (p < 0.001, CI -7.792 to -4.433). The visual analog scale, overall bother, pain at voiding, flank pain at voiding, and frequency of painkiller use scores were significantly higher for control patients than for KTx patients (p = 0.024, <0.001, <0.001, <0.001, and 0.014, respectively). Frequency of rest, changes in work duration, work domain score, suspicion of urinary tract infection (UTI), and need for professional assistance scores were significantly lower for KTx patients than the control. There were no significant differences in general health and sexual domains between groups. Conclusions: KTx recipients have significantly fewer urinary symptoms, pain, work-related disturbances, suspected UTIs, and hospitalizations associated with stent placement than urolithiasis patients.

Utility of pre-transplant lower urinary tract investigation in pediatric renal transplant population after referral: A 16-year institutional experience

To evaluate the clinical utility of pre-renal transplant LUT investigations in pediatric populations after their referral for transplant evaluation based on the etiology of their ESRD. A 16 year retrospective review of patients undergoing RT performed at our institution was performed. Patients were stratified into two groups: Group 1-non-urologic and Group 2-urologic etiology for ESRD. Baseline characteristics, pre-transplant LUT investigations, and urologic interventions were assessed. One-year clinical outcomes were compared between those with and without LUT investigations following referral for renal transplantation (RT). 227 patients and 97 patients were identified for Groups 1 and 2, respectively. 19% of Group 1 and 73% of Group 2 had VCUG, while 1% and 13%, respectively, had UDS ordered following referral for RT. In both groups, >50% of VCUG and UDS were ordered without specific clinical concerns. These had low likelihood of prompting interventions, both pre-transplant (Group 1-VCUG 0%, UDS 0%; Group 2-VCUG 0%, UDS 8%) or post-transplant (Group 1-0%, Group 2-5%). In both groups, LUT investigation following referral for RT did not lead to differences in 1 year outcomes assessed. In anticipation of pediatric RT, LUT investigations ordered without clinical indications did not provide information that altered management prior to transplantation.

Increasing bladder capacity and vesicoureteral reflux in pediatric kidney transplant patients

OBJECTIVES

To investigate the frequency of vesicoureteral reflux, and the relationship of pretransplant decreased bladder capacity and post-transplant vesicoureteral reflux in children undergoing kidney transplantation.

METHODS

A voiding cystourethrography was carried out in 172 pediatric kidney transplantation recipients before, and 4 months after, transplantation to evaluate bladder capacity and vesicoureteral reflux. The correlation of post-transplant vesicoureteral reflux with pretransplant bladder capacity, vesicoureteral reflux in the native kidney and the method of ureteral reimplantation (intravesical/extravesical) was analyzed. Atrophic bladder was defined as having ≤50% functional bladder capacity (age in years + 2) × 25 (mL) or ≤150 mL in patients aged >10 years.

RESULTS

Bladder capacity increased remarkably after transplantation in both post-transplant vesicoureteral reflux- group (from 180 to 253 mL) and vesicoureteral reflux+ group (from 82 to 171 mL). Voiding cystourethrography showed vesicoureteral reflux in 12 cases of kidney transplantation (7%; grade 1: 2, grade 2: 3, grade 3: 7). Pretransplant atrophic bladder was an independent risk factor of post-transplant vesicoureteral reflux (P = 0.004, hazard ratio 9.5). There was no difference in renal function between the vesicoureteral reflux- group and vesicoureteral reflux+ group at 4 months to 5 years post-transplantation.

CONCLUSIONS

Pretransplant atrophic bladder is a risk factor of post-transplant vesicoureteral reflux in pediatric patients. However, bladder capacity can remarkably increase after transplantation, and kidney function in the post-transplant vesicoureteral reflux+ group is stable.