Antenatal and Preoperative Factors Associated with 2-Year Outcome of Preterm Newborns with Biventricular Complex Congenital Heart Defects: A 23-Year Cohort Study

<b>Introduction:</b> To explore whether antenatal and preoperative factors predict disability-free survival of preterm newborns with biventricular complex congenital heart defects (CHD). <b>Methods:</b> Retrospective cohort study, using the prospectively designed database of Complex Pediatric Therapies Follow Up Program and a chart review of mother-newborn dyads, born under 37 weeks' gestation with biventricular complex CHD, between 1997 and 2019, who had open heart surgery up to 6 weeks corrected age. Surviving children had neurodevelopmental assessments between 18 and 24 months corrected age. Bayley Scales of Infant Development, 2nd edition, and Bayley Scales of Infant and Toddler Development, 3rd edition, assessed cognitive, language, and motor skills; Adaptive Behavior Assessment System, 3rd edition, assessed adaptive skills. Univariate and multivariate analyses assessed predictors of mortality, disability (cerebral palsy, visual impairment, permanent hearing loss), and neurodevelopmental delay. <b>Results:</b> Of 84 preterm newborns (34.6 ± 2.1 weeks' gestation, 2321 ± 609 g, 57% males), 8 (9.5%) died by 2 years of age; 69 (91%) survived without and 7 (9%) with disability. Chorioamnionitis was associated with death [Hazard ratio 7.92 (95% CI 1.3, 33.3), <i>p</i> = 0.025]; prolonged rupture of membranes was associated with disability [Odds Ratio 9.7 (95% CI 1.99, 46.9), <i>p</i> = 0.005]. Maternal diabetes, antenatal diagnosis of CCHD, birth head circumference, cardiopulmonary resuscitation, and chromosomal anomalies were associated with adverse neurodevelopment. <b>Conclusions:</b> Chorioamnionitis and prolonged rupture of membranes are associated with worse outcomes in preterm newborns with biventricular complex CHD up to 2 years of age. Adverse neurodevelopmental outcomes are associated with maternal diabetes and antenatal diagnosis of CCHD. Prospective studies are needed to confirm these results.