Persistent Markers of Kidney Injury in Children Who Developed Acute Kidney Injury After Pediatric Cardiac Surgery:A Prospective Cohort Study

Background Acute kidney injury (AKI) after pediatric cardiac surgery is common. Longer-term outcomes and the incidence of chronic kidney disease after AKI are not well-known. Methods and Results All eligible children (aged <16 years) who had developed AKI following cardiac surgery at our tertiary referral hospital were prospectively invited for a formal kidney assessment ≈5 years after AKI, including measurements of estimated glomerular filtration rate, proteinuria, α1-microglobulin, blood pressure, and kidney ultrasound. Longer-term follow-up data on kidney function were collected at the latest available visit. Among 571 patients who underwent surgery, AKI occurred in 113 (19.7%) over a 4-year period. Fifteen of these (13.3%) died at a median of 31 days (interquartile range [IQR], 9-57) after surgery. A total of 66 patients participated in the kidney assessment at a median of 4.8 years (IQR, 3.9-5.7) after the index AKI episode. Thirty-nine patients (59.1%) had at least 1 marker of kidney injury, including estimated glomerular filtration rate <90 mL/min per 1.73 m2 in 9 (13.6%), proteinuria in 27 (40.9%), α1-microglobinuria in 5 (7.6%), hypertension in 13 (19.7%), and abnormalities on kidney ultrasound in 9 (13.6%). Stages 1 to 5 chronic kidney disease were present in 18 (27.3%) patients. Patients with CKD were more likely to have an associated syndrome (55.6% versus 20.8%, P=0.015). At 13.1 years (IQR, 11.2-14.0) follow-up, estimated glomerular filtration rate <90 mL/min per 1.73 m² was present in 18 of 49 patients (36.7%), suggesting an average estimated glomerular filtration rate decline rate of -1.81 mL/min per 1.73 m² per year. Conclusions Children who developed AKI after pediatric cardiac surgery showed persistent markers of kidney injury. As chronic kidney disease is a risk factor for cardiovascular comorbidity, long-term kidney follow-up in this population is warranted.