Distal Ureteral Diameter Ratio is More Predictive of Outcome in Patients with Primary Vesicoureteral Reflux than Ureteral Diameter Alone
Angela M. Arlen, MD1, Andrew J. Kirsch, MD2, Traci Leong, PhD2, Christopher S. Cooper, MD1.
1University of Iowa Hospitals and Clinics, Iowa City, IA, USA, 2Children's Healthcare of Atlanta and Emory University, Atlanta, GA, USA.
Spontaneous resolution of vesicoureteral reflux (VUR) is impacted by multiple factors, and management, including the decision to pursue surgical correction, should therefore be individualized. Voiding cystourethrogram (VCUG) has marked potential to provide detailed information about the functional and anatomical status of the urinary tract, including ureteral dilation. Increased ureteral diameter (UD) has been reported as a risk factor for persistent reflux, and distal ureteral diameter ratio (UDR) has recently been shown to be more predictive of outcomes than grade in children with primary VUR.
VCUGs of children with primary VUR were reviewed. The largest UD within the pelvis was measured and then normalized by dividing by distance from the L1-L3 vertebral body giving the UDR. Both UD and UDR were tested in uni- and multivariate analysis. Primary outcome was status of reflux at last clinical follow-up (i.e. resolution, persistence or surgical intervention). Patient demographics, VUR grade, timing of reflux, laterality, and history of urinary tract infection were also assessed.
One hundred and forty-seven children (98 girls, 49 boys) were diagnosed with primary VUR at a mean age of 5.5 ± 4.7 months. Of the 147 patients, 67 (45.6%) resolved spontaneously, 55 (37.4%) had persistent disease at the end of the follow up period and 25 (17%) were surgically corrected. Median time to resolution (censoring patients at the time of surgical correction or those with persistent disease) was 21.5 months (95% CI 17-25 months). On univariate analysis, children who had spontaneous resolution had significantly lower VUR grade, refluxed later in
the bladder cycle, and had lower UD and UDR (all p values <0.001). In a multivariate model, grade of VUR (p = 0.001), age (p = 0.008), UD (p = 0.02) and UDR (p < 0.0001) retained statistical significance. For every 0.1 unit increase in UDR, there was a 2.6 (95% CI 1.58-4.44) increased odds of persistent disease compared to a 1.28 (95% CI 1.07-1.52) increased odds of persistent disease for every 1 mm increase in UD. The correlation of UDR and UD with VUR grade was significantly greater than 0 demonstrating a positive linear relationship [Table]. Correlation with UDR was 0.68 (p <0.0001; 95% CI 0.58-0.76) and was 0.60 (p<0.0001; 95% CI 0.48-0.69) with UD. Only 3 (4.5%) of children with resolution had a UDR of >0.35; however high UD did not preclude resolution.
Maximal distal ureteral diameter and ureteral diameter ratio are readily accessible on VCUG, and provide an objective measure of VUR. While both UD and UDR are associated with VUR grade, the ureteral diameter ratio is a more accurate predictor of outcome than ureteral diameter alone, as it adjusts for differences in magnification during VCUG.
|VUR grade||UDR, Mean (SEM)||UD, Mean (SEM)|
|1-2(n = 52)||.19 (.01)||4.50 mm (.29)|
|3 (n = 51)||.23 (.01)||5.25 mm (.32)|
|4 (n = 31)||.40 (.03)||9.10 mm (.66)|
|5 (n = 13)||.52 (.05)||11.78 mm (1.62)|
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