An initial differential renal function between 35% and 40% has greater probability of leading to normal after pyeloplasty in patients with unilateral pelvic-ureteric junction obstruction

Deep Learning Algorithms to Predict Differential Renal Function <40% in Unilateral Hydronephrosis Based on Key Parameters of Urinary Tract Ultrasound

OBJECTIVE

To identify the correlation between ultrasound findings and the incidence of differential renal function (DRF) <40%, we conducted an analysis of the key parameters of urinary tract ultrasound in children with unilateral hydronephrosis. For children with unilateral hydronephrosis, DRF <40% serves as a compelling indication for surgical intervention, and it can be assessed through diuretic renogram. However, a significant number of patients do not have convenient access to high-quality renograms. So we conducted this analysis aiming to identifying value of urinary tract ultrasound in surgical intervention decision.

METHODS

We retrospectively reviewed the dynamic renogram and urinary tract ultrasound data of 802 children with hydronephrosis presented to our department. Independent risk factors related to DRF <40% were screened out. Several machine learning models were employed. The area under receiving operating curves (AUROC) was calculated for each model to compare their efficiency.

RESULTS

The renal pelvis anterior-posterior diameter, upper calyx dilation, and renal length ratio were found to be independent risk factors for DRF <40%. Among these factors, the renal length ratio had the highest AUROC of 0.820. These 3 factors, alone with the patients' age, were then introduced into 3 machine learning models: random forest, logistic regression, and support vector machines (SVM), among which, the SVM exhibited the highest AUROC of 0.941, with a sensitivity of 90.32% and a specificity of 81.03%.

CONCLUSION

The length ratio exhibited the strongest correlation with DRF <40% among multiple ultrasound indices. Moreover, the SVM model exhibited significant improvement compared to individual factors. Therefore, it can be employed to identify high-risk children with impaired renal function in the assessment of congenital hydronephrosis.

Can pyeloplasty restore normal renal function in patients with severe unilateral ureteropelvic junction obstruction and DRF < 35

PURPOSE

To assess the outcome of successful pyeloplasty in infants with Ureteropelvic Junction Obstruction (UPJO) and a differential renal function of (DRF) < 35% whether they can attain normal postoperative renal function or not.

METHODS

All children who were diagnosed with antenatal hydronephrosis due to UPJO were presented to our institutions and were prospectively followed up. Pyeloplasty was performed based on predefined indications such as: initial DRF ≤40%, progression of hydronephrosis, and febrile urinary tract infection (UTI). A total of 173 children, who had successful surgical intervention due to impaired DFR, were divided according to their pre-intervention DRF value as follows: DRF <35% (group I) and DRF 35-40% (group II). The renal morphology and function changes were recorded and used for comparison between both groups.

RESULTS

Group I was comprised of 79 patients, and group II included 94 patients. Pyeloplasty achieved significant improvement in the anatomical and functional indices in both groups (p-value <0.001). The degree of improvement in Anteroposterior diameter (APD) and cortical thickness was comparable in both groups (P-value, 0.64 and 0.44 respectively). While the improvement in the DRF was significantly higher in group I (16.06 ± 6.6) than in group II (6.25 ± 2.66) (P-value <0.001). Despite that, a significantly higher percentage of infants in group II (61.7%) achieved normal final DRF compared with only (10.1%) in group I (Figure).

CONCLUSION

Even in severely impaired renal function (<35%), successful pyeloplasty can recover a significant part of lost renal function. However, most of these patients do not achieve normal postoperative renal function.

Factors predicting improvement of differential renal function after pyeloplasty in children of ureteropelvic junction obstruction

INTRODUCTION

To evaluate differential renal function (DRF) in unilateral ureteropelvic junction obstruction (UPJO) patients under 18 years old after pyeloplasty and to identify factors predicting postoperative improvement.

MATERIAL AND METHODS

A total of 95 patients with unilateral UPJO treated by pyeloplasty between March 2019 to March 2020 were prospective enrolled. All patients had preoperative dynamic renal scintigraphy and were required to review after surgery 6 months. We defined DRF improvement as postoperative DRF increased ≥5% (If preoperative DRF less than 55%) or postoperative DRF reduced ≥5% and reached a normal range (45-55%) (preoperative DRF more than 55%) with drainage improvement. Drainage improvement indications were defined as a resolution of symptoms; decrease in hydronephrosis without requiring additional procedures and T_1/2＜20min in dynamic renal scintigraphy. All parameters were statistically compared.

RESULTS

In the study, 28 (29.5%) patients showed improvement in postoperative DRF, and 67 (70.5%) patients maintained stable postoperative DRF. Gender, age, baseline DRF, anteroposterior pelvic diameters (APD), minimum and maximum renal parenchymal thickness (PT), and anterior-posterior diameter/maximum renal parenchymal thickness (APD/PT) were correlated with postoperative DRF improvement in univariable analysis. In the multivariable analyses, maximum PT and APD/PT were predictors of improvement in postoperative DRF.

DISCUSSION

In our study, the maximum PT was associated with the improvement of renal function in patients with UPJO, and when the thickest part of the renal parenchyma was measured, APD/PT can predict the improvement of renal function. We infer that the compression of the thickest part of the renal parenchyma may be the reason for the impaired renal function in some patients, and when the obstruction was relieved, the compressed parenchyma function can be significantly improved.

CONCLUSIONS

Postoperative DRF of UPJO patients can be effectively improved and preserved through pyeloplasty. Maximum PT and APD/PT can predict improvement of renal function in patients with UPJO after pyeloplasty.

Changes in differential renal function after pyeloplasty in infants and children

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis in pediatric populations. Many need surgical intervention. The aim of surgery is preserving renal function and reducing symptoms such as urinary tract infections and pain.

OBJECTIVES

The objectives were to evaluate differential renal function (DRF) in infants and children after surgery for UPJO and to identify factors predicting postoperative improvement. The difference in outcomes between patients with antenatal hydronephrosis and those diagnosed later was evaluated.

STUDY DESIGN

A total of 85 children (63 boys and 22 girls) aged 0-16 years, treated for UPJO with dismembered pyeloplasty, were followed up as per a structured protocol including ultrasounds and renal scans (MAG-3) pre-operatively and three and 18 months postoperatively. Five children with bilateral or single kidney UPJO were excluded. Patient records were retrospectively reviewed, and the patients were grouped as per prenatal (group 1, n = 23) or postnatal (group 2, n = 57) diagnosis. Univariable and multivariable logistic regression analyses searching for factors predicting >5% postoperative improvement in DRF on the obstructed side were performed. Factors included in analyses were age at diagnosis and surgery, sex, type of presentation, cause of obstruction, estimated glomerular filtration rate, pre-operative DRF, anteroposterior diameter (APD), APD/renal parenchymal thickness, and grade of hydronephrosis as per the Onen alternative grading system (grade 1-4).

RESULTS

Pre-operative DRF on the obstructed side was a mean of 42% (standard deviation, 12), with no difference between the groups. The median age at surgery was 0.9 (0.2-10) and 8.1 (0.6-16) years in groups 1 and 2, respectively (P < 0.001). The majority had unchanged DRF 18 months postoperatively, 19 (27%) patients improved by >5%, and one deteriorated. The proportion of patients with improved DRF was higher in group 1 (n = 10; 45%, P = 0.026). Anteroposterior diameter, APD/parenchymal thickness, pre-operative DRF, and antenatal diagnosis were predictors in the univariable analyses, and high APD (odds ratio [OR] = 1.1, P = 0.0023), antenatal diagnosis (OR = 0.23, P = 0.048), and low pre-operative DRF (OR = 0.90, P = 0.0045) built the best model of independent factors predicting improvement in DRF in multivariable analyses (Summary Figure).

DISCUSSION

The limitation of the study is that it is retrospective, but it has the advantage of a uniform follow-up protocol, including patients from a five-year period, with few lost to follow-up. The results can be of interest in evaluating factors of importance for predicting recovery of function in obstructive uropathies in children.

CONCLUSION

The majority of children had preserved or improved function after surgery for UPJO. Those with an antenatal diagnosis displayed a greater ability to catch up in DRF, and high APD, antenatal diagnosis, and low pre-operative DRF were independent predictive factors of an improvement in renal function after pyeloplasty.

Ultrasound-Based Scoring System for Indication of Pyeloplasty in Patients With UPJO-Like Hydronephrosis

Background: Previous scoring systems have used renal scan parameters to assess severity of ureteropelvic junction obstruction-like hydronephrosis (UPJO-like HN), however this information is not always reliable due to protocol variation across centers and renogram limitations. Therefore, we sought to evaluate the Pyeloplasty Prediction Score (PPS), which utilizes only baseline ultrasound measurements to predict the likelihood of pyeloplasty in infants with UPJO-like. Methods: PPS was developed using three ultrasound parameters, Society of Fetal Urology (SFU) grade, transverse anteroposterior (APD), and the absolute percentage difference of ipsilateral and contralateral renal lengths at baseline. PPS was evaluated using prospectively collected prenatal hydronephrosis data (n = 928) of patients with UPJO-HN. Children with vesicoureteral reflux. primary megaureter, other associated anomalies, bilateral HN and <3 months of follow-up were excluded. Scores were analyzed regarding its usefulness in predicting which patients would be more likely to undergo pyeloplasty. Sensitivity, specificity, likelihood ratios (LR) and receiver operating characteristic (ROC) curve were determined. Results: Of 353 patients, 275 (78%) were male, 268 (76%) had left UPJO-like HN, and 81 (23%) had a pyeloplasty. The median age at baseline was 3 months (IQR 1-5). The PPS system was highly accurate in distinguishing patients who underwent pyeloplasty using baseline ultrasound measurements (AUC: 0.902). PPS of 7 and 8 were found to have a sensitivity of 85 and 78%, and specificity of 81 and 90%, respectively. PPS of 8 was associated with a LR of 7.8, indicating that these patients were eight times more likely to undergo pyeloplasty. Conclusion: Overall, PPS could detect patients more likely to undergo pyeloplasty using baseline ultrasound measurements. Those with a PPS of eight or higher were eight times more likely to undergo pyeloplasty.

Do gynecologic oncology patients with severely diminished renal function and urinary tract obstruction benefit from ureteral stenting or percutaneous nephrostomy?

Objective

To assess the renal outcomes of gynecologic oncology patients who present with hydronephrosis and acute kidney injury (AKI), have <20% renal function on diuretic renal scintigraphy, and undergo placement of a ureteral stent or percutaneous nephrostomy (PCN) tube.

Methods

This is a single-institution case series of gynecologic oncology patients who underwent diuretic renal scintigraphy from January 1, 2007, to June 1, 2017. Univariate and multivariate logistic analyses were used to assess predictors of <20% renal function. Recovery from AKI or elevated creatinine was reported for women with <20% renal function who received a unilateral ureteral stent or PCN tube on the same side as their more compromised kidney.

Results

Among 353 gynecologic oncology patients who underwent diuretic renal scintigraphy, 58 (16%) had renal function <20%. Mean age was 59.6 years, 17% had preexisting chronic kidney disease, and 44% had a diagnosis of cervical cancer. Renal atrophy on computed tomography scan (aOR 18.24, 95% CI 1.21–274.92) predicted renal function <20%. Of 10 women with <20% renal function who received a stent or PCN tube, 7 recovered from AKI or elevated creatinine.

Conclusions

Gynecologic oncology patients with <20% renal function may recover from AKI after placement of a stent or PCN tube, indicating that a diuretic renal scintigraphy cutoff of <20% renal function may be overly conservative. Future studies are warranted to determine optimal renal function cutoffs for stent/PCN tube placement in gynecologic oncology patients.

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Renal atrophy on CT scan is an independent predictor of severely compromised renal function.

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Gynecologic oncology patients with <20% renal function may recover from AKI after placement of a stent or PCN tube.

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<20% relative renal function on diuretic renal scintigraphy may be an overly conservative cutoff for kidney salvageability.

Diuretic renography in hydronephrosis: a retrospective single-center study

PURPOSE

Ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis other than transient hydronephrosis. In children with unilateral hydronephrosis, mercaptoacetyltriglycine-3 diuretic renography (MAG₃) is used to calculate differential renal function and to assess drainage. The aim of our study is to examine whether anteroposterior pelvic diameter on renal ultrasound (US) scan can predict both differential renal function (DFR) and obstruction in pediatric patients, and whether an US adequately identifies those patients who need further investigation. We also aimed to design a study with a larger sample size than previous studies investigating the relationship between MAG₃ and US.

METHODS

We retrospectively reviewed the MAG₃, US, dimercaptosuccinic acid scan (DMSA) findings, and medical records of pediatric patients with hydronephrosis and/or atrophy who were at follow-up between January 2013 and December 2016 in our center which is located in the south-east region of Turkey.

RESULTS

Two hundred and twenty-five pediatric patients (M/F = 156/69) with unilateral hydronephrosis but without VUR were enrolled in this study. The mean age of the children was 45.4 ± 48.3 months (range 2-173 months). Sixty-nine patients had obstructive pattern on ^99mTc-MAG₃. With respect to obstructive pattern, there was a significant difference between the hydronephrosis groups both with 15 and 20 mm border. An APD of greater than 20 mm had 15.8 times (95% CI 5.72-43.69) higher likelihood of having obstruction MAG3 findings. On the other hand, an APD of greater than 15 cm had 9.2 times (95% CI 3.01-28.57) higher likelihood of having obstruction MAG₃ findings. The incidence of urinary tract infections was lower than in the obstructive group than the other groups. The regression analysis showed that an APD of greater than 20 mm was a risk factor for low DRF (OR = 5.208, 95% CI 1.529-17.743, p = 0.008). However, the regression analysis showed that an APD of greater than 15 mm was not a risk factor low DRF.

CONCLUSIONS

The combination of ultrasound and MAG₃ provides the necessary anatomical and functional information to follow the degree of obstruction and to decide between surgical intervention and conservative follow-up. Our study supports a threshold of 20 mm rather than 15 mm for severe obstruction and a low DRF. An APD threshold greater than 15 mm did not have a predictive value in DRF estimation.