Fellow Physician Baylor College of Medicine Houston, Texas, United States
Background: Infants with congenital diaphragmatic hernia (CDH) have altered hemodynamic milieu secondary to malaligned fetal cardiac structures. Following repair, mediastinal shift including the heart and lung units may lead to better lung expansion, better cardiac preload thus changing loading conditions of the heart with resultant improvement in overall hemodynamic status. The vasoactive inotropic score (VIS), which takes inotropic medication exposure into account, is a well-studied bedside tool to assess hemodynamic status of neonates. Objective: Our objective with the current study was to delineate the impact of an atrial level shunt on the VIS following CDH repair. Design/Methods: This is a retrospective chart review of 57 babies with a diagnosis of CDH at a single center. Factors analyzed Included-Atrial septal defect (ASD) shunt direction, Patent Ductus Arteriosus (PDA) shunt direction, and ventricular dysfunction. VIS was evaluated in the post-repair period. One factor analysis of variance (ANOVA) was used to compare VIS score among groups for each factor, with Tukey’s honestly significant differences test used for post-hoc analysis. If two factors were significant for an outcome at a given time point, two factor ANOVA was used to analyze both factors simultaneously. Results: At the 1st post-repair echo, the VIS differed significantly with ASD shunt direction (p=0.003) and PDA shunt direction (p=0.025). The mean VIS for patients with L-R ASD shunt was significantly lower compared to patients without an ASD shunt (p=0.002). Mean VIS for patients with R-L shunt direction across the PDA trended higher than bidirectional PDA shunt direction (p=0.061) and absent PDA shunt (p=0.079). VIS did not differ significantly for patients with versus without severe LV dysfunction (p=0.762) in the post-repair echocardiogram. When we utilized two factor ANOVA model to simultaneously compare mean VIS across these two categories, VIS differed significantly across ASD shunt direction categories, independent of PDA shunt direction (p=0.003).
Conclusion(s): Direction of atrial level shunting in postoperative patients may be influenced by the mediastinal shift and resultant improvement in ventricular function and compliance as indicated by the lower VIS. Further investigation is needed to confirm our findings and also to test if atrial level shunting plays a beneficial role in offloading the non-compliant left heart, and impact ductal level shunting and overall cardiac hemodynamics.
