Background

Infants born extremely preterm are at high risk for developing bronchopulmonary dysplasia (BPD) and mortality which may be increased further if associated with a hemodynamically significant PDA. The aim of this study was to determine if transcatheter PDA closure (TCPC) altered the observed mortality and BPD rates from expected rates.

Methods

This was a single center study (July 2017-June 2023) using infants born 23-28 weeks’ gestation and birth weight 501-1249 grams who underwent TCPC (infants on mechanical ventilator (MV) and O2 support with PDA diameter> 2mm by echocardiogram and descending aorta flow reversal on Doppler). The National Institute of Child Health and Human Development (NICHD) outcome calculator was used to estimate the risk of death or developing BPD. The observed BPD incidence was graded as per the NICHD definition.

Results

The median gestational age, birth weight, procedure age and procedure weight were 24 (23-28) weeks, 700 (501-1200) grams, 27 (9-68) days and 900 (540-1900) grams respectively for the 236 infants (53% male) included in the study. The average estimated risk for mortality, severe, moderate, mild and no BPD at the time of TCPC were 15.2±9.4%, 27.9±7.6%, 32.3±7.1%, 19.2±8.2%, and 3.4±2.1% respectively. Following TCPC, the rates for the aforementioned groups were 3.3%, 30.5%, 39.8%, 14.8% and 11.4% respectively. The mortality rate was significantly lower and the proportion of infants with no BPD were significantly higher than estimated (P< 0.01 for both). Age at TCPC> 28 days was the only significant predictor for severe BPD (OR= 3.7, 95% CI= 1.9-6.8; P< 0.01).

Conclusion

In this high-risk cohort of premature infants that underwent TCPC, the mortality and BPD rates were lower than estimated. Delayed PDA closure was associated with the development of a higher grade of BPD. Future randomized trials are required to validate the results of this study.