1349075 - Differences in pulmonary artery stiffness measured by CMR in preterm born young adults with and without bronchopulmonary dysplasia compared with controls.

About 10% of adults has been born prematurely and this percentage is increasing. Those born prematurely are at increased risk for cardiopulmonary diseases later in life (1). This may relate to decreased pulmonary arterial elastance, as has been shown invasively (2). For follow-up of this population, it is important to be able to non-invasively follow pulmonary artery (PA) elastance. The aim of our study was to investigate if individuals born prematurely (with or without bronchopulmonary dysplasia (BPD)) have increased pulmonary vascular stiffness compared to at term born individuals in early adulthood, using cardiovascular magnetic resonance (CMR).

Methods:

60 young adults were included in this study: 20 premature born with BPD (median gestational age (GA) 27 weeks (Interquartile range (IQR) 26-28)), 20 premature born without BPD (GA 28 weeks (IQR 27-29)) and 20 at term born young adults (GA 39 weeks (IQR 38-40)). CMR (1.5T) was performed including phase contrast imaging of the PA (~1 cm above the valve proximal to bifurcation) and bSSFP cine imaging for ventricular volumes and function. Vascular elastance was approximated with pulse wave velocity (PWV) based on the early systolic flow and area method and relative area change (3, 4). Wilxocon test was used to calculate differences between groups.

Results:

The age of all 60 included individuals was 23 (± 2) years (33 female; 27 male  ). No differences were found for age, sex, body mass index and body surface area between the different groups. In 57 of the 60 CMRs vascular stiffness measurements could be performed. In 3 premature born with BPD individuals no accurate contours of the pulmonary artery could be drawn.

Figure 1 shows a lower pulmonary artery relative area change in the preterm group (with BPD and without BPD) compared to at term born subjects (p< 0.001 and p=0.006). No significant difference was shown between preterms with and without BPD (p=0.10). PA PWV was higher in preterms with BPD compared to those without BPD (p=0.039) and to at term subjects (p=0.036). There was no significant difference between preterms without BPD and at term subjects (p=0.46). In agreement with previous studies, left and right ventricular end-diastolic volume (LVEDV & RVEDV) was reduced in preterms with BPD compared to at term subjects (LVEDV 80±11ml/m² vs. 91±14ml/m², p=0.03; RVEDV 85±12ml/m² vs. 91±14ml/m² p=0.02) and left ventricular mass was comparable.

Conclusion:

Using (non-invasive) CMR we demonstrated clear differences in PA vascular elastance for preterm born young adults. Even in preterms without BPD there are signs of abnormal PA vascular characteristics. This is in agreement with invasive data in literature for those with BPD and has not previously been demonstrated for preterms without BPD at this age (2). CMR could be used for research and follow-up in this growing population at risk for cardiovascular events.