The choice of perioperative inotropic support impacts the outcome of small infants undergoing complex cardiac surgery: an observational study

Vaso-inotropic agents are frequently used to prevent and/or treat low cardiac output syndrome in infants undergoing surgery for congenital heart disease. Due to the lack of comparative studies, their use is largely dependent on physician- and center preferences. The aim was to assess the impact of two different inotropic regimens, milrinone-epinephrine versus dobutamine on postoperative morbi-mortality in young children undergoing complex cardiac surgery.

All consecutive children younger than one year of age admitted for complex cardiac surgery (Risk Adjustment in Congenital Heart Surgery-1 [RACHS-1] score ≥3) with cardiopulmonary bypass (CPB) from January 2008 to December 2018 were included. Children received either milrinone in association with low dose epinephrine (milrinone-epinephrine group) or dobutamine (dobutamine group) groups were matched and compared using a propensity score. Our primary outcome was a composite measure including either hospital death and/or the presence of at least two of the following events: respiratory failure, prolonged inotropic support, or renal failure.

Two hundred and fifty patients were included in the analysis. Children in the milrinone-epinephrine group (N.=184) suffered more frequently from a cyanotic heart disease and had longer surgery, CPB, and aortic cross clamp times than those in the dobutamine group (N.=66). After matching, children in the milrinone-epinephrine group had a higher incidence of severe postoperative morbidity or mortality compared to those in the dobutamine group (27.4 versus 13.9%; P=0.016). Respiratory failure (28% vs. 12%), prolonged inotropic support (71% vs. 35%) and in-hospital death (3 vs. 0%) were more frequent in the milrinone-epinephrine group.

In young infants undergoing complex cardiac surgery, milrinone combined with epinephrine is associated with a higher incidence of postoperative morbidity or mortality compared to dobutamine for perioperative inotropic support. Further prospective randomized studies are required to confirm this finding.