Six-hour renal resistive index as an early marker of acute kidney injury after infant cardiac surgery: a prospective cohort study

BACKGROUND: Acute kidney injury after infant congenital cardiac surgery is common and worsens outcomes. Renal resistive index may aid early postoperative risk stratification. OBJECTIVE: To evaluate a single six-hour postoperative renal resistive index as an early acute kidney injury marker and its association with postoperative haemodynamic support. METHODS: = 22). Renal resistive index was measured at six hours (primary), 48 hr, and discharge. Postoperative acute kidney injury was diagnosed using Kidney Disease: Improving Global Outcomes serum creatinine and urine output criteria over 48 hr. Vasoactive-inotropic score was recorded, and discrimination was assessed using receiver operating characteristic analysis. RESULTS: < 0.001). Three acute kidney injury infants required peritoneal dialysis, all with six-hour renal resistive index ≥ 0.90. CONCLUSIONS: A six-hour renal resistive index may help early acute kidney injury risk assessment after infant cardiac surgery. External validation is warranted.