# Association between intrarenal venous flow Doppler and postoperative acute kidney injury in children undergoing cardiac surgery: A retrospective cohort study

## TL;DR

This study found that abnormal kidney blood flow patterns in children after heart surgery are linked to a higher risk of kidney injury, suggesting early detection could help prevent complications.

## Contribution

The study identifies intrarenal venous Doppler patterns as a novel predictor of postoperative acute kidney injury in pediatric cardiac surgery patients.

## Key findings

- 12.1% of patients developed postoperative acute kidney injury (AKI).
- AKI patients showed higher rates of abnormal renal venous flow patterns compared to non-AKI patients.
- Higher preoperative ICU admission and lower albumin levels were associated with AKI.

## Abstract

The role of intrarenal Doppler parameters in predicting postoperative acute kidney injury (AKI) has been increasingly emphasized, but remains underexplored in children undergoing cardiac surgery. This study aimed to investigate the association between intrarenal venous Doppler patterns and the occurrence of postoperative AKI in children after congenital cardiac surgery. This retrospective study included 338 pediatric patients who underwent elective cardiac surgery between June 2019 and December 2021. Intrarenal blood flow Doppler measurements were performed before and after surgery. The primary outcome was the difference in postoperative renal venous Doppler patterns between patients with and without AKI according to the Kidney Disease: Improving Global Outcomes criteria. Multivariate logistic regression analysis was performed to identify factors associated with AKI. Of the 338 patients, 12.1% developed postoperative AKI. Patients with AKI had a higher prevalence of biphasic and monophasic renal venous flow patterns than those without AKI (63.5% vs. 19.9%, p < 0.001). The AKI group had higher pre- and postoperative renal resistive index than the non-AKI group. Discontinuous renal venous flow pattern, preoperative intensive care unit admission, higher Risk Adjustment for Congenital Heart Surgery-1 score and intraoperative vasoactive-inotropic score, and lower preoperative albumin levels were associated with postoperative AKI.

Conclusion: Abnormal postoperative intrarenal venous Doppler patterns were associated with AKI in pediatric patients after congenital cardiac surgery. Intraoperative Doppler assessment of renal venous flow may help identify children at a higher risk of AKI, allowing for early interventions.