Serum brain natriuretic peptide and risk of acute kidney injury after cardiac operations in children.

Background: Acute kidney injury (AKI) after pediatric cardiac operations is associated with poor outcomes and is difficult to predict. We conducted a prospective study to evaluate whether preoperative brain natriuretic peptide (BNP) levels predict postoperative AKI among children undergoing cardiac operations.

Methods: This was a three-center, prospective study (2007-2009) of 277 children undergoing cardiac operations (n = 121, aged <2 years) with available preoperative BNP values. Preoperative BNP was measured and categorized into tertiles. The performance of BNP was evaluated alone and in combination with clinical factors. AKI was defined as doubling of serum creatinine or need for acute dialysis.

Results: Postoperative AKI occurred in 165 children (60%), with 118 cases (43%) being mild and 47 cases (17%) severe. Preoperative BNP was not associated with increased risk of mild or severe postoperative AKI and did not significantly improve AKI risk prediction when added to clinical models. Preoperative BNP was, however, associated with several clinical outcomes, including length of stay and mechanical ventilation. The results were similar when the analysis was repeated in the subset of children younger than 2 years of age or when the association of postoperative BNP and AKI was evaluated.

Conclusions: Preoperative BNP levels did not predict postoperative AKI in this cohort of children undergoing cardiac operations. Both preoperative and postoperative BNP levels are associated with postoperative outcomes. Clinical Trial Registration at Clinicaltrials.gov as NCT00774137.