Early cardiac function and death, severe bronchopulmonary dysplasia and pulmonary hypertension in extremely preterm infants

Association between early cardiac function and neonatal outcomes are scarcely reported. The aim of the current study was to describe this association with death, severe bronchopulmonary dysplasia (BPD) and BPD-related pulmonary hypertension (PH).

Retrospective cohort study of infants <29 weeks born between 2015 and 2019. Infants with clinically acquired echocardiography at ≤21 days after birth were included and data were extracted by an expert masked to outcomes.

A total of 176 infants were included. Echocardiogram was performed at a median of 9 days (IQR 5-13.5). Of these, 31 (18%) had death/severe BPD and 59 (33.5%) had death/BPD-related PH. Infants with death/severe BPD were of lower birth weight (745 [227] vs 852 [211] grams, p = 0.01) and more exposed to invasive ventilation, late-onset sepsis, inotropes and/or postnatal steroids. Early echocardiograms demonstrated decreased right ventricular [Tricuspid Annular Plane Systolic Excursion: 5.2 (1.4) vs 6.2 (1.5) cm, p = 0.03] and left ventricular function [Ejection fraction 53 (14) vs 58 (10) %, p = 0.03]. Infants with death/BPD-related PH had an increased Eccentricity index (1.35 [0.20] vs 1.26 [0.19], p = 0.02), and flat/bowing septum (19/54 [35%] vs 20/109 [18%], p = 0.021).

In extremely premature infants, altered ventricular function and increased pulmonary pressure indices within the first 21 days after birth, were associated with the combined outcome of death/severe BPD and death/BPD-related PH.

Decreased cardiac function on echocardiography performed during first three weeks of life is associated with severe bronchopulmonary dysplasia in extremely premature infants. In extreme preterm infants, echocardiographic signs of pulmonary hypertension in early life are associated with later BPD-related pulmonary hypertension close to 36 weeks post-menstrual age. Early cardiac markers should be further studied as potential intervention targets in this population. Our study is adding comprehensive analysis of echocardiographic data in infants born below 29 weeks gestational age.