Predictive value of proximal and distal ureteral diameter ratio for impacted stones in the middle and upper ureter / 中华泌尿外科杂志

ABSTRACT

Objective:To evaluate the predictive value of proximal ureteral diameter (D1)to distal ureteral diameter (D2)ratio (DDR) for impacted stones in the middle and upper ureter.Methods:The clinical data of 173 patients with middle and upper ureteral calculi admitted to the Third Hospital of Shanxi Medical University from January 2014 to November 2021 were retrospectively analyzed. There were 75 males and 98 females, with the median age of 56.0 (51.0, 62.0) years old and median body mass index of 26.1 (24.8, 27.2) kg/m 2. The imaging data of the patients were analyzed. The impacted stones were defined as the inability of the contrast agent to pass through the site of obstruction when intravenous urography or CT urography was performed, resulting in the inability of the ureter to visualize normally in parts below the site of obstruction. D1 was defined as the proximal ureteral diameter at the lower pole of the kidney on horizontal CT images. D2 was defined as the ureteral diameter 3 cm from the calculi. The stone diameter, stone CT value, D1, D2, and DDR were compared between impacted stone group and non-impacted stone group. Univariate logistic regression analysis was used to analyze the different indicators. Random number table was used to divide the training set and validation set according to the ratio of 7∶3. Through least absolute shrinkage and selection operator(LASSO) regression analysis, the independent influencing factors were obtained and the nomogram model was established (Model 1). Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to verify the predictive efficacy of the model, and the other three effective models (Model 2-4) were constructed by stepwise multivariate logistic regression. The deLong test was used to compare whether there was a significant difference in the AUC between Model 1 and the other three models, and the net benefit of patients was analyzed by clinical decision curve analysis(DCA). Results:In this study, 64 cases (37.0%) were impacted ureteral calculi and 109 cases (63.0%) were non-impacted ureteral calculi, and there were significant differences in diameter[7.8(6.2, 8.8)mm vs. 6.3(5.2, 8.1)mm] , CT value[878.5(763.8, 940.5)HU vs.764.0 (613.0, 854.0) HU], D1[11.1(8.9, 14.9) mm vs. 9.1(7.1, 10.8) mm], D2[4.1(3.1, 4.9) mm vs. 5.0(4.1, 5.9) mm] and DDR[3.1(2.3, 3.9) vs. 1.8(1.4, 2.4)] between the two groups( P < 0.05). The results of univariate logistic regression analysis showed that stone diameter ( OR = 1.333, P < 0.001), CT value ( OR = 1.002, P=0.002), D1 ( OR = 1.146, P<0.001), D2 ( OR = 0.652, P < 0.001) and DDR ( OR = 2.995, P<0.001) were the influencing factors of impacted stones. The training set and validation set included 122 cases and 51 cases, respectively, without significant differences in their image characteristics and outcomes ( P > 0.05). The results of LASSO regression analysis showed that λ corresponding to the simplest result in the optimal range was 0.0908, and three variables were included at this time, and the influencing factors of impacted stones were stone diameter (coefficient 0.0700, OR = 1.073), CT value (coefficient 0.0003, OR = 1.001) and DDR (coefficient 0.5960, OR = 1.815). Moreover, Model 1 was established. According to the model fitting results, ROC curves were plotted, and the AUC of Model 1 was 0.862, and the AUCs of Model 2-4 were 0.859, 0.762, and 0.793, respectively. After deLong test, there was no significant difference between Model 1 and Model 2 ( Z = 0.248, P = 0.804). The AUC of Model 1 was superior to that of Model 3 ( Z = 2.888, P = 0.004) and Model 4 ( Z = 2.321, P = 0.020). The DCA suggested that Model 1 could improve the net benefit rate by up to approximately 21% of patients. Conclusions:DDR is the influencing factor of impacted ureteral calculi, and the model constructed by DDR, stone CT value and stone diameter can effectively predict the probability of impacted ureteral calculi in the middle and upper ureter.