Patency of the Ductus Arteriosus at 72 h in Extremely Preterm Infants Born at Two Altitudes in Colombia: A Preliminary Descriptive Study.

Patent ductus arteriosus (PDA) is common in preterm neonates, especially before 28 weeks' gestation, and is associated with morbidity such as bronchopulmonary dysplasia, hemorrhage, and necrotizing enterocolitis. Beyond immaturity, perinatal factors, postnatal interventions, and altitude, may affect ductal persistence; altitude is proposed as a modifier, though evidence is limited. The objective of the study is to describe the prevalence, the clinical, and echocardiographic characteristics of PDA at 72 h of life in neonates born before 28.6 weeks of gestation in two Colombian cities located at different altitudes. A prospective observational descriptive study with exploratory analysis was conducted from January 2022 to January 2024 in Bucaramanga (959 m above sea level) and Pasto (2,527 m above sea level). Sixty neonates born before 28.6 weeks underwent color Doppler echocardiography at 72 h. Hemodynamically significant PDA was defined using a standardized, center-agreed echocardiographic scoring system criteria adapted from previously described criteria. Patent ductus arteriosus was present in 85% of neonates at 72 h, although only 11.7% (n=7) fulfilled criteria for hemodynamic significance (hs). The frequency of hsPDA did not differ between altitudes. Neonates with hsPDA showed no differences in inotropic support, ventilatory support, or oxygen requirements. No differences were observed in other variables either, such as birth weight, gestational age, surfactant type, or early fluid intake. No differences in early PDA persistence or hemodynamic relevance were observed between altitudes. However, the high prevalence of PDA at 72 h supports the need for early, structured echocardiographic follow-up to identify hemodynamic compromise and guide timely clinical decision-making.