Short-term Respiratory and Hemodynamic Outcomes Following Transcatheter PDA Closure in Premature Infants

Background: Patent ductus arteriosus (PDA) is associated with increased risk of necrotizing enterocolitis, renal failure, bronchopulmonary dysplasia (BPD), and death. Traditional management options relied on conservative approach, medical treatment or surgical ligation. Respiratory deterioration with hypotension (post-ligation syndrome) is observed in as many as 45% of preterm infants undergoing surgical ligation. In recent years, effective devices for transcatheter PDA closure (TCPC) of premature infants have been approved.

Methods: A retrospective chart review from 5/2018 to 5/2021 was performed at the University of California Davis Medical Center level 4 NICU. Infants ≤29w0d gestation and ≤1500 g diagnosed with HsPDA who underwent TCPC were included. HsPDA was defined by a ductus arteriosus (DA) >1.5 mm in diameter and a pulmonary score >0.5. The pulmonary score (FIO2 * respiratory support score + medication score) was used to compare respiratory support 72h pre- and 72h post-TCPC. FIO2 is expressed as a fraction and Respiratory support score =2.5 if on invasive mechanical ventilation, 1.5 if on non-invasive support, and 1.0 if on nasal cannula; Medication score: steroids=0.2 and caffeine=0.05 (Madan A et al. Pediatrics 2005). If these criteria were met, infants were treated with acetaminophen, ibuprofen, or indomethacin. If a HsPDA persisted after medical treatment, TCPC was considered. Patients with congenital heart defects were excluded.

Results: Twenty-five infants met inclusion criteria. Median weight (IQR) and gestational age at birth were 710g (600, 810) and 24w (24, 25), respectively. Weight and postmenstrual age (PMA) at TCPC were 890g (760, 1058) 27w (26, 28), respectively. Mean pulmonary scores (SD) at 24h pre- and 72h post-TCPC were 0.766 ±0.32 and 0.906 ±0.42 respectively (p=0.13 Figure 1). Analysis of 19 patients who were on mechanical ventilation prior to TCPC showed mean pulmonary scores (SD) at 24h pre- and 72h post-TCPC of 0.884 ±0.29 and 0.938 ±0.27 respectively (p=0.32). Blood pressures were significantly higher post-TCPC (Table 1) and there was no difference in vasoactive inotropic score pre- and post-TCPC. Median (IQR) extubation days after TCPC was 8 (2, 12). Respiratory support at 36w PMA (n=21) were as follows (data is missing from 4 patients, 3 transfers and 1 death): 1/21 (5%) on mechanical ventilation, 12/21 (57%) on high flow nasal cannula ≥2 lpm >21% O2 or CPAP/non-invasive ventilation and 8/21 (38%) on nasal cannula (NC). Upon discharge, 5/21 (24%) were in room air, 15/21(71%) on NC and 1/21 (5%) on a home vent.

Conclusion: In extremely premature infants with a HsPDA, TCPC is safe and effective and is associated with a significant increase in blood pressures. There is no short-term change in the pulmonary score with TCPC. Large randomized controlled studies are warranted to determine long-term respiratory and neurodevelopmental outcomes.