Aim Bronchopulmonary dysplasia, which occurs most frequently in extremely prematurely born infants, can be complicated by pulmonary hypertension due to dysregulation of angiogenesis and increased muscularisation of the pulmonary arteries. (1) Our aim study was to assess, whether at school age, pulmonary artery pressures differed between children born very prematurely and those born at term.
Methods Transthoracic echocardiography was performed at 11–14 years in children born extremely prematurely (<29 weeks of gestation) who had been entered into the United Kingdom Oscillation Study and in term born children. Measurements were performed according to the American Society of Echocardiography guidelines. Tricuspid regurgitation (TR) was assessed in the apical four-chamber view and parasternal right ventricular inflow. A minimum of three sequential complexes were recorded. Continuous-wave Doppler of the peak regurgitant jet velocity was used to estimate the right-ventricular-to-right-atrial (RV-RA) systolic pressure gradient with the use of the modified Bernoulli equation. The mean RV-RA gradient was calculated by tracing the TR time-velocity integral. (2) Pulmonary hypertension was defined as a peak TR jet velocity ≥ 2.5 m per second. The difference in the echocardiographic results between term and preterm children were examined using mixed models, which allowed for clustering due to multiple births. The p-values reported are based on unadjusted models.
Results Echocardiographic results were analysed from 191 preterm and 45 term born children. The preterm compared to the term born children had higher mean TR peak velocity (2.21 vs. 1.89, p < 0.001), systolic RV-RA gradient (19.9 vs. 14.5, p < 0.001) and mean RV-RA gradient (14.0 vs. 11.3, p < 0.001). TR velocity was measurable in 78% of term born and 69% of preterm children; 13% of preterm children, but no term born child had a peak TR velocity of >2.5 m/s (p = 0.011).
Conclusion Extremely prematurely born children have higher pulmonary artery pressures at school age than those born at term.
Mourani PM et al, Pulmonary vascular effects of inhaled nitric oxide and oxygen tension in bronchopulmonary dysplasia. Am J Respir Care Med 2004;170:1006–1013
Fikret E. et al, Accuracy of Doppler-Echocardiographic Mean Pulmonary Artery Pressure for Diagnosis of Pulmonary Hypertension, www.plosone.org, Dec2010, Volume 5, Issue 12
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