445 - Dexamethasone is associated with Ductal Closure in Extremely Preterm Infants with Evolving Lung Disease

Publication Number: 3430.445

Phoenix Plessas-Azurduy, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Joshua Hazan Mea, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Thomas Sonea, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Pasinee Kanaprach, Chaophaya Yommarat Hospital, Suphanburi, Suphan Buri, Thailand; Sariya Sahussarungsi, Thammasat University, Khlong Luang, Pathum Thani, Thailand; Carolina Michel Macías, McGill University Faculty of Medicine and Health Sciences, Queretaro, Queretaro de Arteaga, Mexico; Shiran S. Moore, McGill University Faculty of Medicine and Health Sciences, Port Washington, NY, United States; Punnanee Wutthigate, Mahidol University, Bangkok, Krung Thep, Thailand; Jessica Simoneau, MUSC Children's Hospital, Montreal, PQ, Canada; Daniela Villegas Martinez, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Andréanne Villeneuve, CHU Sainte-Justine, Montréal, PQ, Canada; Anie Lapointe, Universite de Montreal Faculty of Medicine, Montreal, PQ, Canada; Guilherme Santanna, McGill University Health Center, MONTREAL, PQ, Canada; Gabriel Altit, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada

Background: Dexamethasone (DEXA) is frequently administered to extremely preterm infant with evolving lung disease, yet its influence on patent ductus arteriosus (PDA) dynamics remains poorly understood, especially in neonatal intensive care units practicing conservative PDA management.

Objective: To evaluate the trajectory of PDA size and closure rates following DEXA administration. We hypothesized that DEXA treatment would be associated with a progressive ductal constriction an increased likelihood of closure.

Design/Methods: We conducted a prospective observational cohort study of infants born at < 29 weeks' gestation (GA) who received DEXA for treatment of severe lung injury/inflammation. Serial echocardiographic images were obtained at seven predefined timepoints: baseline (prior to DEXA initiation), days 3, 7, and 14 of treatment, 1- and 2-weeks post-therapy, and at 36 weeks corrected GA. PDA diameter and flow pattern were measured by a blinded evaluator using standardized protocols. Longitudinal data were analyzed using a generalized estimating equations (GEE) model or a random mixed effects model.

Results: Between 2021-2024, 57 neonates were enrolled, of which 53 had a PDA diagnosed at baseline (mean GA 24.3 ± 5.3 weeks, birth weight 759 ± 192g, 59% male, 79% inborn) - Table 1. By day 7 of DEXA, 62% of the PDAs were closed/restrictive; by one week post-DEXA cessation 76% were closed or restrictive (Figure 1). With each timepoint, there was an increase in the likelihood of PDA closure (b: 0.35, p < 0.001). At 36 weeks corrected GA, 95% of infants demonstrated complete closure or restrictive PDA. Only 5 infants received pharmacological PDA treatment and 1 PDA was surgically ligated.

Conclusion(s): DEXA administration was associated with a consistent temporal reduction in PDA size and patency. Beyond its pulmonary benefits, DEXA may support spontaneous ductal closure in extremely preterm infants through favorable cardiovascular remodeling.

Table 1: Clinical characteristics of population.
Abbreviations: PMA (postmenstrual age); NEC (necrotizing enterocolitis); PDA (patent ductus arteriosus); HTN (hypertension); d (days); g (grams); w (weeks); APGAR (appearance, pulse, grimace, activity, respiration); IQR (interquartile range); CPAP (continuous positive airway pressure); NIMV (non-invasive mechanical ventilation); NAVA (neurally adjusted ventilatory assist); MV (mechanical ventilation); HFOV (high-frequency oscillatory ventilation); HFJV (high-frequency jet ventilation). Results are presented as n (%), mean ± standard deviation or median [IQR].

Figure 1: Trajectory of PDA profiles across study timepoints.
Most infants N=40/42 (95%) with an unrestrictive PDA at DEXA initiation had complete closure or a restrictive PDA pattern by 36 weeks PMA.

Figure 2: Median PDA size and open/closed PDA counts across study timepoints.
A PDA measuring 0 mm in size was considered closed. After 14 days of DEXA treatment, the cohort achieved PDA closure, with a median size of 0 mm [0-1.5]. Of the ducts remaining open throughout the whole study (N=13) the PDA sizes decreased from a median of 2.3 mm [1.8-2.7] at baseline to 1.4 mm [1-1.9] at 36 weeks PMA.