Infants born before 29 weeks of gestation demonstrated abnormal pulmonary artery acceleration time (PAAT) at 1-year corrected age, regardless of neonatal lung disease status, according to the results of a study published in The Journal of Pediatrics.

Philip T. Levy, MD, of the Department of Pediatrics, Washington University School of Medicine in St Louis, Missouri, and colleagues set out to test the hypothesis that echocardiographic markers of pulmonary vascular disease (PVD) exist in asymptomatic infants born preterm at 1-year corrected age. They conducted a prospective cohort study of 80 infants born preterm and 100 age- and weight-matched infants born at term and compared broad-based conventional and quantitative echocardiographic measures of pulmonary hemodynamics at 1-year corrected age.

Using PAAT, a validated index of pulmonary vascular resistance, arterial pressure, and compliance, they assessed pulmonary hemodynamics. A lower PAAT score is indicative of PVD. The researchers performed subanalyses in infants with bronchopulmonary dysplasia (BPD; n=48; 59%) and/or late-onset pulmonary hypertension (n=12; 15%).

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At 1 year, the investigators found no differences between conventional measures of pulmonary hypertension in infants born at term and those born prematurely. However, all infants born preterm had significantly lower PAAT values than infants born at term (73 milliseconds vs 98 milliseconds, P <.001). Infants born preterm with BPD had even lower PAAT than infants without BPD (69 milliseconds vs 79 milliseconds, P <.01). At 1-year corrected age, the degree of PVD was inversely related to gestation in all infants born preterm. Data analysis accounted for ventricular function and other confounding factors.

The authors argued that these results suggest the existence of PVD beyond infancy. They noted that although this PVD is commonly associated with BPD, it appears to be a distinct pathology of prematurity. They further suggested that PAAT measurements may offer a reliable, noninvasive tool for screening and longitudinal monitoring of pulmonary hemodynamics in infants.

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Levy PT, Patel MD, Choudhry S, Hamvas A, Singh GK. Evidence of echocardiographic markers of pulmonary vascular disease in asymptomatic infants born preterm at one year of age [published online April 3, 2018]. J Pediatr. doi:10.1016/j.peds.2018.02.006