Using kinetic eGFR to identify acute kidney injury risk in children undergoing cardiac transplantation.

BACKGROUND: Acute kidney injury (AKI) is common following pediatric cardiac transplantation. Since no treatments exist, strategies focus on early identification and prevention. Kinetic glomerular filtration rate (kGFR) was developed to assess renal function in the non-steady state. Although used to predict AKI in adults, kGFR has not been explored in children. Our study examines AKI and the ability of kGFR to identify AKI risk in pediatric heart transplant recipients. METHODS: One hundred and seventy-five patients under 21 years who underwent cardiac transplantation at Lucile Packard Children's Hospital between September 2007-December 2017 were included. kGFR1 was calculated using pre-operative and immediate post-operative creatinines; kGFR2 was calculated with the first two post-operative creatinines. The primary outcome was AKI as defined by the Kidney Disease: Improving Global Outcomes criteria. RESULTS: One hundred and thirty-one (75%) and 78 (45%) patients developed AKI and severe AKI, respectively; 5 (2.9%) required dialysis. kGFR was moderately associated with post-operative AKI risk. The adjusted area under the curve (AUC) for kGFR1 was 0.72 (discovery) and 0.65 (validation). The AUC for kGFR2 was 0.72 (discovery) and 0.68 (validation). CONCLUSIONS: AKI is pervasive in children undergoing cardiac transplant, particularly in the 24 h after surgery. kGFR moderately identifies AKI risk and may represent a novel risk stratification technique. IMPACT: Our research suggests that kGFR, a dynamic assessment of renal function that uses readily available laboratory values, can moderately identify AKI risk in children undergoing cardiac transplantation. Current published studies on kGFR are in adult populations; this study represents the first formal study of kGFR in a pediatric population. kGFR may serve as an early AKI indicator, allowing providers to implement preventative strategies sooner in a patient's clinical course.