PROGNOSTIC MODEL OF HIGH-PRESSURE BALLOON DILATATION EFFECTIVENESS FOR PRIMARY OBSTRUCTIVE MEGAURETER TREATMENT IN CHILDREN
Dmitry Shakhnovskiy, MD, Sergei ZORKIN, MD, PhD, Alexandra GALUZINSKAYA, MD, Evgeniy PETROV, MD.
National Medical Research Center for Children's Health, Moscow, Russian Federation.
BACKGROUND:Currently one of the minimally invasive treatment options for primary obstructive megaureter (POM) in children is endoscopic high pressure balloon dilatation (HPBD). It was shown to be an effective alternative for ureteral reimplantation, but there are no clear indications for its application and reliable efficiency prognostic model. The aim of this study was to develop an efficiency prognostic model of HPBD for POM in children.
Methods: From 2020 to 2022 a total of 200 children aged 1 month to 2 years were treated by HPBD. Results were evaluated using ultrasonography and MAG-3 renogram at 6 months following the procedure. Positive outcome we considered a decrease of pelvic anteroposterior and distal ureteral diameters and an improvement of drainage according to renogram. HPBD was performed using cardiac balloon catheters, followed by J-stent placement. In all patients we assessed stenosis length, ureteral lumen diameter and area of stenosis before and after a procedure.
RESULTS:Overall success rate was 92.5%. The most statistically significant predictors of good treatment outcome were length of ureteral stenosis less than 1.7 mm (p<0.001), ureteral stenosis diameter more than 0.4 mm (p<0.001) and area of ureteral stenosis less than 96.8% (p<0.001). Based on three obtained HPBD efficiency predictors, we developed a binomial logistic regression model.Depending on length of ureteral stenosis before a procedure in mm. (x1), ureteral stenosis diameter before a procedure in mm. (x2) and area of ureteral stenosis before a procedure in percent (x3) the equation for probability of a successful procedure outcome was: P=1/1+e-(61,2237 - 1,4632x1 + 13,7686x2 - 0,6415x3). The chi-square of the model was 67.14, which, in the presence of three degrees of freedom, corresponded to p<0.0001. Area under the ROC curve was 0.977 with 95% CI: 0.951 - 0.996 (p < 0.0001). Threshold value at the cut-off point was 0.9083. Positive outcome was predicted for value higher than cut-off point.
CONCLUSIONS:Results of this study confirm that HPBD proved its effectiveness for vast majority of primary obstructive megaureter cases. The use of a newly developed linear logistic regression model allows to predict the effectiveness of HPBD in POM. Obtaining P value of a model greater than or equal to 0.9083 predict a positive treatment result. In case of prognostic treatment efficiency is less than 51.7% ureter reimplantation is indicated.
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