Delayed upper tract drainage on voiding cystourethrogram may not be associated with increased risk of urinary tract infection in children with vesicoureteral reflux

The ureteral diameter ratio as a predictive factor in renal scarring associated with primary vesicoureteral reflux

INTRODUCTION

The ureteral diameter ratio (UDR) is reported to be effective in predicting the outcomes of vesicoureteral reflux (VUR) in several studies.

OBJECTIVE

The objective of the current study was to compare the risk of scarring in patients with VUR relative to UDR and the VUR grade. We also aimed to demonstrate other associated risk factors in scarring and investigate the long-term complications of VUR and their relationship with UDR.

STUDY DESIGN

Patients diagnosed with primary VUR were retrospectively enrolled in the study. UDR was calculated by dividing the largest ureteral diameter (UD) by the distance between L1-L3 vertebral bodies. Demographic and clinical data, laterality, VUR grade, UDR, delayed upper tract drainage on voiding cystourethrogram, recurrent urinary tract infections (UTI), and long-term complications of VUR were compared between the patients with and without renal scars.

RESULTS

A total of 127 patients and 177 renal units were included in the study. There was a significant difference between the patients with and without renal scars according to age at diagnosis, bilaterality, reflux grade, UDR, recurrent UTI, bladder bowel dysfunction, hypertension, decreased estimated glomerular filtration rate, and proteinuria. The logistic regression analysis revealed that UDR had the highest odds ratio among the factors affecting scarring in VUR.

DISCUSSION

VUR grading based on the evaluation of the upper urinary tract is one of the most important predictors for treatment options and prognosis. However, it is more likely to reflect ureterovesical junctional anatomy and function, which play a crucial role in the pathogenesis of VUR.

CONCLUSION

UDR measurement seems to be an objective method that can help clinicians predict renal scarring in patients with primary VUR.

Additional VCUG-related parameters for predicting the success of endoscopic injection in children with primary vesicoureteral reflux

INTRODUCTION AND OBJECTIVE

Prediction of vesicoureteral reflux (VUR) prognosis and decision for treatment are usually made according to the reflux grading classification. But the management of VUR is still controversial since there are difficulties in distinguishing reflux grade due to inter- and intra-observer variations. Previous studies have demonstrated that the distal ureteral diameter ratio (UDR) on voiding cystourethrography (VCUG) may be more predictive for clinical prognosis than reflux grade. We aimed to predict the success of endoscopic injection in primary VUR by creating new models that include other additional parameters (timing of reflux, delayed post-voiding contrast drainage of the upper urinary tract) as well as UDR.

STUDY DESIGN

A total of 200 patients aged 2-15 years with primary VUR undergoing endoscopic injection were retrospectively evaluated. Demographic and clinical data for a total of 248 renal units were recorded. Besides reflux grade and laterality, distal ureteral diameter, UDR, timing of reflux [early filling, late filling or voiding] and presence of contrast delay in upper tract drainage were also assessed on VCUG. According to the complete resolution of VUR on the control VCUG at the postoperative 3rd month, the renal units were divided into two main groups: successful (n = 171, 68.9%) and unresolved (n = 77, 31.1%) RESULTS: The failure rate of endoscopic injection was found to be 4.068 times greater with early filling reflux on VCUG, 3.076 times greater with UDR>0.24, 2.745 times greater with delayed contrast drainage of the upper urinary tract, 2.666 times greater with the presence of scar in DMSA, 2.493 times greater with bladder-bowel dysfunction and 2.341 times greater with febrile urinary tract infection. We also observed that a model in which all VCUG-related parameters were combined provided a better estimation of endoscopic injection outcomes compared to only the reflux grade (AUC: 0.903 vs. 0.604, respectively).

DISCUSSION

Distal ureteral dilatation is considered to be a more decisive factor for clinical outcomes of primary VUR rather than upper urinary tract dilatation since ureterovesical junction anatomy plays a more important role in primary VUR pathophysiology. Studies investigating new prediction models on this topic have recently become more popular. However, a consensus has not yet been achieved.

CONCLUSION

We consider that UDR level, the timing of reflux and delayed upper tract drainage on VCUG may be more predictive parameters of endoscopic injection success compared with reflux grade, and could facilitate selecting the best candidates for surgery.