WIP 50 - Clinical validity of the definition of non-significant patent ductus arteriosus during transition in extremely low gestational age neonates

Publication Number: WIP 50.7450

Federica Savio, The Hospital for Sick Children, Toronto, ON, Canada; Poorva Deshpande, Mount Sinai Hosptial, Toronto, ON, Canada; Ashraf Kharrat, Mount Sinai Hospital, Toronto, ON, Canada; Amish jain, University of Toronto Temerty Faculty of Medicine, Toronto, ON, Canada; Faith Zhu, University of Toronto Temerty Faculty of Medicine, Toronto, ON, Canada

Background: Patent ductus arteriosus (PDA) with a diameter < 1.5 mm and/or a restrictive shunt is typically classified as “non-significant (nsPDA)” and often excluded from treatment in clinical practice and trials. These criteria are based on studies in more mature preterm infants, highlighting the need for evaluation in extremely low gestational age neonates (ELGANs). In practice, nsPDA can subsequently enlarge, increasing the risk of complications.

Objective: To identify early clinical and echocardiographic (ECHO) features that differentiate between progression to large PDA and spontaneous closure among ELGANs initially diagnosed with nsPDA.

Design/Methods: This is a single-center, retrospective cohort study conducted in a tertiary neonatal intensive care unit (NICU) from January 2023 to July 2024. All admitted ELGANs during this period underwent routine ECHO screening for PDA ≤72 hours age. Inclusion criteria: gestational age < 27 weeks, initial ECHO showing nsPDA (diameter < 1.5 mm and/or restrictive shunt [maximal (Vmax)/minimal velocity (Vmin) ratio < 2]), and no PDA treatment after first ECHO. Exclusion criteria: infants with acute illness requiring cardiotropic drugs or inhaled nitric oxide at first ECHO, lack of follow-up ECHO to confirm final PDA status, or PDA treatment without prior ECHO. The cohort will be divided based on primary outcome of progression to “large PDA” (diameter ≥1.5 mm, unrestrictive shunt) as diagnosed by ECHO ≤14 days of age. Intergroup comparisons will include demographic and perinatal variables, ventilation status at first ECHO, and predefined ECHO variables [PDA diameter, Vmax and ratio with Vmin, mean pressure gradient, peak pulmonary vein velocity, left ventricular output, and diastolic flow in systemic arteries]. Logistic regression and ROC analysis will identify predictors for large PDA. Institutional research ethics board approval (REB 24-0144-C) was obtained, with data collection ongoing and expected completion of study by January 2025. This project aims to establish a clinically informed definition of nsPDA for ELGANs early in postnatal life.