Ultrasound-Based Renal Parenchymal Area and Kidney Function Decline in Infants With Congenital Anomalies of the Kidney and Urinary Tract

Abstract

Congenital anomalies of the kidney and urinary tract are the leading cause of chronic kidney disease in children. Noninvasive imaging biomarkers that predict chronic kidney disease progression in early infancy are needed. We performed a pilot study nested in the prospective Chronic Kidney Disease in Children cohort study to determine the association between renal parenchymal area (RPA) on first post-natal renal ultrasound and change in estimated glomerular filtration rate (eGFR) in children with congenital anomalies of the kidney and urinary tract. Among 14 participants, 78.6% were males, the median age at the time of the ultrasound was 3.4 months (interquartile range, 1.3-7.9 mo), and the median total RPA z-score at baseline was -1.01 (interquartile range, -2.39 to 0.52). After a median follow-up period of 7.4 years (interquartile range, 6.8-8.2 y), the eGFR decreased from a median of 49.4 mL/min per 1.73 m2 at baseline to 29.4 mL/min per 1.73 m2, an annual eGFR percentage decrease of -4.68%. Lower RPA z-scores were correlated weakly with a higher annual decrease in eGFR (Spearman correlation, 0.35; 95% confidence interval, -0.25 to 0.76). This pilot study shows the feasibility of obtaining RPA from a routine ultrasound and suggests that a lower baseline RPA may be associated with a greater decrease in eGFR over time. Further studies with larger patient cohorts are needed to confirm this association.

Keywords: CKD; children; congenital anomalies; kidney; renal parenchymal area; urinary tract.

Conflict of interest statement

Conflict of interest: All authors declare having no conflicts of interest.

Copyright © 2021 Elsevier Inc. All rights reserved.

Figures

Figure 1:

Flow chart showing subject selection

Figure 2:

Using ImageJ software we manually outlined the contour of the gross renal area (a). Renal collecting system (b) was then subtracted from the gross renal area to measure the RPA

Figure 3:

Relationship of estimated GFR annual percent change and RPA z-score measured on ultrasound of 13 participants. The baseline estimated GFR stages are depicted by color: blue shows baseline eGFR ≥ 60 ml/mi/1.73m2 and red depicts baseline eGFR