Impact of Nonhemodynamically Significant Patent Ductus Arteriosus on Pulmonary Function in Premature Neonates

To quantify the impact of nonhemodynamically significant patent ductus arteriosus (non-hsPDA) on pulmonary function in neonates.

We analyzed a retrospective cohort of very low birthweight (<1500 g) infants born <32 weeks' gestation admitted to a single tertiary neonatal intensive care unit between 2019 and 2023 who underwent both echocardiography and pulmonary function testing at approximately 34 weeks postmenstrual age. Infants with ventricular or atrial septal defects were excluded. Passive respiratory compliance (Crs) was compared among infants with hsPDA, non-hsPDA, and age-matched controls without PDA using one-sided t-tests and ANOVA, with multivariable regression controlling for birth weight and length.

Twenty-four infants were analyzed (8 hsPDA, 8 non-hsPDA, 8 controls). Mean Crs was significantly reduced in both hsPDA (0.83 ± 0.34 mL/cmH₂O/kg) and non-hsPDA (0.92 ± 0.21) groups compared with controls (1.23 ± 0.34; P < .05). The presence of PDA demonstrated a stepwise inverse relationship with Crs that persisted after adjustment for covariates.

Even non-hsPDAs are associated with measurable reductions in pulmonary compliance among preterm infants. These findings suggest that current binary classifications of PDA significance may underestimate pulmonary impact and support re-evaluation of management thresholds for "non-significant" shunts.