90 Systemic doppler velocities in newborns with congenital heart defects - A prospective study

Abstract Background Neonates with congenital heart disease (CHD) are at high risk for systemic steal, hypoperfusion, and organ dysfunction due to abnormal cardiac anatomy and persistent shunts. Understanding these physiological changes is crucial for optimizing management strategies and improving outcomes. Objectives To evaluate longitudinal ultrasonographic (US) estimators of systemic blood flow during the postnatal transition in neonates with CHD using Doppler measurements of the aorta (Ao) during the first week of life. Design/Methods This prospective observational single-center study recruited neonates born at ≥34 weeks' gestation between 2018 and 2021 with CHD requiring NICU admission. Infants with significant genetic anomalies were excluded. Daily Aortic (Ao) ultrasounds were performed until day 7 of life, discharge, or cardiac intervention. Pulse-wave Doppler measurements were obtained from the suprasternal (ascending, preductal and postductal descending Ao) and subcostal views (postductal Ao). Key measurements included velocity-time integral (VTI), peak systolic velocity (PSV), end-diastolic velocity (EDV), and mean velocity (VM). Temporal changes and associations with retrograde flow were analyzed using mixed-effects models to assess systemic blood flow dynamics during the postnatal transition. Results Of the 62 enrolled neonates, data from 22 were analyzed (work in progress). CHD types in this cohort are detailed in Table 1. Over the first week, heart rate significantly increased (Table 2). VTI at the ascending aorta increased over time (β = 0.004, p = 0.03), and VM increased at both the ascending (β = 0.02, p = 0.009) and preductal sites (β = 0.02, p = 0.009), suggesting compensatory mechanisms to maintain cerebral perfusion (while PVR is dropping). Retrograde flow was linked to significant HR increases (Table 2) and VM decreases at the subcostal (β = –0.12, p = 0.02) and postductal sites (β = –0.2, p < 0.001). EDV at the subcostal site became more negative with retrograde flow (β = –0.19, p = 0.005). Conclusion Preliminary data suggest neonates with CHD undergo significant hemodynamic changes during the early postnatal period, including increased HR and differencial flow velocity time evolution in pre and post ductal Aorta, reflecting compensatory mechanisms for maintaining cerebral and systemic perfusion. These findings emphasize the value of hemodynamic monitoring to provide real-time insights not always evident through standard assessments, aiding in optimizing clinical management.