Incidence of acute kidney injury in infants with dextrotransposition of the great arteries after arterial switch operation (an observational cohort single-center study)

Introduction
Transposition of the great arteries (TGA) is a type of congenital cardiac disease that affects 4.7/10,000 live births. The arterial switch operation (ASO) is the most preferred surgery to repair this anomaly. Cardiopulmonary bypass (CPB) is imperative to perform the operation. Prolonged exposure to the CPB can affect the liver, brain, kidneys, gastrointestinal tract, and heart. This study aimed to evaluate the effect of CPB on the development of acute kidney injury (AKI) in infants with TGA who underwent the ASO and to validate the applicability of neutrophil gelatinase-associated lipocalin (NGAL) for diagnosis of AKI.

Material and methods
The single-center study included 390 cases. All patients were classified using the pediatric risk, injury, failure, loss, end stage (pRIFLE) classification to assess the incidence of AKI. 360 cases were retrospective, and thirty cases were prospective; those thirty cases were assessed three times (before the operation, immediately postoperatively, and one week after the operation) with NGAL as a biomarker of renal tubular impairment.

Results
Among a total of 390 patients with transposition of the great vessels who underwent ASO, postoperative urea and creatinine showed a significant increase (p-value < 0.001), and a significant decrease was observed in postoperative glomerular filtration rate (p-value < 0.001). Around 40% of the patients showed positive postoperative AKI according to the pRIFLE classification. There was a significant increase in immediate and one-week postoperative NGAL levels in the thirty prospective cases. At the cut-off point serum NGAL concentration of 15.7 ng/ml, the sensitivity was 100%, and negative predictive value was 100%.

Conclusions
Acute kidney injury is a serious complication that can occur after open-heart surgery. Postoperative NGAL level could be a good indicator for postoperative AKI.