It has been shown that an increased level of Nt-proBNP is an independent predictor of the occurrence of postoperative AKI in the general group of adult patients treated with cardiac surgery as well as in the pediatric group; otherwise, it has been demonstrated that elevated Nt-proBNP values are associated with a prolonged stay in an intensive care unit after cardiac surgery for congenital heart defects [14,15,16]. Here, NPPB is linked to acute kidney injury.