538 - Effectiveness of Pharmacological Treatment of Ductus Arteriosus in Newborns < 1500 grams in Neonatal Units of the Iberoamerican Society of Neonatology (SIBEN) Neonatal Network

During 2021, 40 neonatal units reported data of 1916 newborns (NB’s) ≤
1500 grams to SIBEN’s NETWORK; 486 (25%) had patent ductus arteriosus (PDA) and 323
(66%) received pharmacological treatment. Each unit selects the drug for closure
based on availability and/or local experience. In previous studies, we have observed that
together with indomethacin (INDO) or ibuprofen (IBU), the use of paracetamol (PAR) is high.

Objective:

To determine the effectiveness on PDA closure according to the drug selected for
the first cycle of treatment in clinical care. Secondarily, to describe the need for surgical ligation,
complications and evolution of treated NB’s.

Design/Methods:

Multicenter observational study through analysis of data from SIBEN’s neonatal
network in 2021. NB’s with PDA, treated with INDO, IBU or PAR were included when the effect
after the first full course of treatment was reported to the data base. The independent variables
were: birth weight (BW), gestational age (GA), sex, multiples, prenatal corticosteroids (PC) and
need for intubation in the delivery room. The primary outcome was effective post-treatment
closure; secondary outcomes were the need for surgical ligation, rate of necrotizing enterocolitis
(NEC) and clinical course. Data was analyzed through descriptive statistics, Chi square test and
ANOVA using STATA 16.0. The confounding effect was established by multivariate logistic
regression.

Results:

304 NB’s were included; GA 28.6±2.1 weeks; BW 1134±337g (40% < 1000g); 47%
male, 20% twins, 70% PC and 54% required intubation in the delivery room. PDA treatment:
111 received INDO (36.5%); 97 IBU (32%) and 96 PAR (31.5%). In 107 (35%) there was a
failure to close; 36 NB’s required surgical ligation (12%) and 64 (21%) died. The PAR group had
a higher frequency of PC and significantly lower BW and GA. Failure of pharmacological
closure: 53% with PAR, 34% with IBU and 26% with INDO (p < 0.007). Surgery in 20% of PAR,
9% of IBU and 7% of INDO (p< 0.007); NEC: 27% PAR, 18% INDO, 13% IBU (p< 0.05).
Multivariate analysis showed that the possibility of closure with PAR was significantly lower
(ORa 0.48 95%CI 0.25-0.92) independently of BW and GA. Mortality was also higher with PAR
(ORa 3.1 95% CI 1.3 to 7.3). However, for this finding, there are multifactorial variables that
were not evaluated in this study.

Conclusion(s): In clinical care, INDO was the most effective drug for pharmacological closure of
PDA, followed by IBU. PAR was the least effective drug regardless of BW and GA - this group
also had a greater need for surgical ligation and NEC.