90 - Ductal Shunting in Neonates with CDH: Does the Direction of Flow Predict Clinical Outcomes?

Clinically significant pulmonary hypertension (PH) is a common finding in newborns with congenital diaphragmatic hernia (CDH). Patients with PH often have intermittent or continuous right-to-left shunting through the patent ductus arteriosus (PDA). This shunting depends on multiple factors such as the size of the PDA, compliance of the receiving compartment, the pressure gradient between systemic and pulmonary vascular resistance (SVR, PVR), and right ventricular function. 

Objective: In this study, we sought to compare the clinical outcomes of CDH patients with continuous right-to-left ductal flow versus intermittent (right-to-left flow in systole and left-to-right in diastole) or no right-to-left (i.e. all left-to-right) shunting.

Design/Methods:

A retrospective chart review of 125 patients with CDH from 2011 to 2021 was done to assess the direction of ductal flow on the initial postnatal echocardiogram. Newborns with continuous right-to-left were compared to those with intermittent/no right-to-left ductal shunting in terms of quantitative variables using the two-sample t-test or Wilcoxon rank sum test, depending on normality. Fisher’s exact test was used for categorical variables.

Results:

Directionality of ductal flow was reported on in the initial echocardiogram of 93 patients (Table 1). Newborns with continuous right-to-left (n=20) had a statistically significant increased risk of mortality (p=0.047), need for ECMO (p< 0.001), intubation at 28 days (p=0.02), oxygen at 28 days (p=0.016), increased mechanical ventilation days (p=0.027), and increased number of PH medication exposure (p< 0.001). There was no statistically significant difference in total length of stay (p=0.389) or the total number of days on oxygen p=0.104). Interestingly, there was a significant predominance of male-to-female ratio among infants with continuous right-to-left ductal flow (p=0.028). A comparison of male vs. female patients with intermittent/no right-to-left ductal shunting showed no statistically significant outcomes (Table 2).

Conclusion(s):

Continuous right-to-left shunting across the PDA in neonates with CDH is associated with increased mortality and worse clinical outcomes. Ductal flow pattern is thus an important clinical variable in modulating outcomes in infants with CDH and should be included in predictive models of postnatal disease severity. Future studies should utilize quantitative measures for more critical function assessment and investigate myocardial deformation for subtle functional abnormalities.