N-terminal probrain natriuretic peptide level inversely correlates with cardiac index after arterial switch operation...

Natriuretic peptide levels are associated with cardiac output and ventricular function. We hypothesized that concomitant measurement of the peptide fragments and the hemodynamic parameters could elucidate the associations of these parameters after pediatric cardiac surgery.

After approval of the institutional review board and parents' informed consent, we investigated the clinical data of eight neonates undergoing correction of transposition of the great arteries. We measured the level of N-terminal fragments of prohormones of atrial and brain natriuretic peptides (NT-proANP, NT-proBNP) preoperatively, postoperatively and 12, 24, 48, and 72 h after arrival in the intensive care unit. The hemodynamic status was assessed by transpulmonary thermodilution at the same time points. Creatinine and other laboratory values were analyzed in the first 48 h postoperatively.

NT-proBNP levels were inversely correlated with cardiac index (CI, r = -0.47, P = 0.030), stroke volume index (r = -0.65, P = 0.005), and global end-diastolic volume index (GEDI; r = -0.63, P = 0.011). There was strong inverse correlation between the change of NT-proBNP levels and the change of CI between two consecutive measurements during the postoperative period (r = -0.79, P = 0.001). The NT-proBNP level 12 h after surgery was strongly correlated with the creatinine level of the postoperative 24th hour (r = 0.81, P = 0.014).

NT-proBNP correlated with the hemodynamic parameters and with the severity of renal dysfunction. Therefore, NT-proBNP is a reliable indicator of the circulatory state and the severity of a low output syndrome after arterial switch operation in neonates.