The combination of early echocardiographic evidence of pulmonary vascular disease (PVD) in preterm infants and the need for mechanical ventilation at day 7 are strong risk factors for late respiratory disease (LRD) during early childhood, according to the results of a prospective observational study of preterm infants published in the American Journal of Respiratory and Critical Care Medicine.

Investigators sought to establish whether PVD occurring at 7 days following preterm birth is associated with late respiratory outcomes during childhood. Echocardiograms of all preterm infants were performed at 7 days and at 36 weeks premenstrual age (PMA). Prenatal and early postnatal factors, along with postdischarge follow-up survey data at 6, 12, 18, and 24 months of age, were analyzed to identify early risk factors for LRD. Physician-diagnosed asthma, reactive airway disease, bronchopulmonary dysplasia exacerbation, bronchiolitis, pneumonia, or a respiratory-related hospitalization was used as the definition of LRD.

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Of 221 participants who completed the follow-up and had sufficient data, 61% met LRD criteria. The median patient PMA was 27 weeks (interquartile range [IQR], 25-28 weeks) and median weight was 920 g (IQR, 770-1090 g). Mechanical ventilator (MV) support, gestational diabetes, and PVD at 7 days were all associated with LRD. The combination of MV support and PVD at 7 days was one of the strongest predictors of LRD (odds ratio, 8.1; 95% CI, 3.1-21.9; P <.001).

In addition, modeled prenatal and early postnatal factors were able to accurately inform LRD (area under the curve [AUC], 0.764). When bronchopulmonary dysplasia (BPD) status at 36 weeks PMA was added to the model, the accuracy did not change (AUC, 0.771).

A potential limitation of this study was the reliability of data obtained from surveys, including maternal smoking status and data used to define LRD. Possible recall bias is another potential limitation.

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The investigators suggested that the risk for LRD should be determined early in the postnatal course of preterm infants, allowing for more timely identification of infants considered high risk, as well as the implementation of clinical strategies intended to prevent or lessen poor respiratory outcomes.


Mourani PM, Mandell EW, Meier M, et al. Early pulmonary vascular disease in preterm infants is associated with late respiratory outcomes in childhood [published online October 10, 2018]. Am J Respir Crit Care Med. doi:10.1164/rccm.201803-0428OC