Kidney Outcomes 5 Years After Pediatric Cardiac Surgery: The TRIBE-AKI Study

Importance: Acute kidney injury (AKI) after pediatric cardiac surgery is associated with high short-term morbidity and mortality; however, the long-term kidney outcomes are unclear. Objective: To assess long-term kidney outcomes after pediatric cardiac surgery and to determine if perioperative AKI is associated with worse long-term kidney outcomes. Design, Setting, and Participants: This prospective multicenter cohort study recruited children between ages 1 month to 18 years who underwent cardiopulmonary bypass for cardiac surgery and survived hospitalization from 3 North American pediatric centers between July 2007 and December 2009. Children were followed up with telephone calls and an in-person visit at 5 years after their surgery. Exposures: Acute kidney injury defined as a postoperative serum creatinine rise from preoperative baseline by 50% or 0.3 mg/dL or more during hospitalization for cardiac surgery. Main Outcomes and Measures: Hypertension (blood pressure ≥95th percentile for height, age, sex, or self-reported hypertension), microalbuminuria (urine albumin to creatinine ratio >30 mg/g), and chronic kidney disease (serum creatinine estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m2 or microalbuminuria). Results: Overall, 131 children (median [interquartile range] age, 7.7 [5.9-9.9] years) participated in the 5-year in-person follow-up visit; 68 children (52%) were male. Fifty-seven of 131 children (44%) had postoperative AKI. At follow-up, 22 children (17%) had hypertension (10 times higher than the published general pediatric population prevalence), while 9 (8%), 13 (13%), and 1 (1%) had microalbuminuria, an eGFR less than 90 mL/min/1.73 m2, and an eGFR less than 60 mL/min/1.73 m2, respectively. Twenty-one children (18%) had chronic kidney disease. Only 5 children (4%) had been seen by a nephrologist during follow-up. There was no significant difference in renal outcomes between children with and without postoperative AKI. Conclusions and Relevance: Chronic kidney disease and hypertension are common 5 years after pediatric cardiac surgery. Perioperative AKI is not associated with these complications. Longer follow-up is needed to ascertain resolution or worsening of chronic kidney disease and hypertension.