1353544 - Smaller ventricles but preserved cardiac pumping in adolescents born very preterm

Background: Preterm birth and low birth weight are both associated with cardiac disease including hypertension and heart failure later in life. To what extent fetal growth restriction (FGR) modifies the long-term effects of preterm birth on the cardiovascular system is not fully understood. This study therefore assessed cardiac volumes and function in adolescents born very preterm with or without preceding FGR.

Methods: Adolescents born very preterm due to early onset FGR verified with fetal doppler velocimetry and two control groups with appropriate birth weight (AGA), one delivered at similar gestation and one born at term, underwent CMR for assessment of cardiac volumes and function including ejection fraction, atrioventricular plane displacement and longitudinal and radial contribution to stroke volume. Blood was sampled for NT-proBNP.

Results: Seventy adolescents were included (13–16 years; 51% girls) (Table 1). Figure 1 shows left and right ventricular volumes and left ventricular mass normalized to body surface area. Adolescents born very preterm AGA showed smaller left (80 vs 88 ml/m2; p = 0.02) and right (85 vs 97 ml/m2; p = 0.03) ventricles compared to term AGA. No differences were observed between preterm FGR and term AGA for the left or right ventricle, respectively (82 vs 88 ml/m2; p = 0.39, and 94 vs 97 ml/m2; p = 0.82). Left ventricular mass was not different between preterm FGR, preterm AGA, and term AGA (47 vs 43 vs 47 ml/m2; p=0.22). Ejection fraction for the left and right ventricle was for preterm FGR (55% and 51%), for preterm AGA (56% and 52%) and for the term AGA group (54% and 52%), with no differences between groups for the left (p = 0.33) or right (p = 0.46) ventricle, respectively. Atrioventricular plane displacement and longitudinal and radial contribution to stroke volume did not differ between groups for the left (all p ≥ 0.17) or right ventricle (all p ≥ 0.07) (Figure 2). NT-proBNP was for preterm FGR 26 ng/l (5 – 80 ng/l), for preterm AGA 28 ng/l (14 – 87 ng/l) and for term AGA 18 ng/l (5 – 87 ng/l) with no difference between groups (p = 0.73).

Conclusion: Very preterm birth is associated with smaller ventricles whereas clinical measures of cardiac function including ejection fraction, longitudinal and radial pumping and left ventricular mass were unaffected. Early onset FGR did not exacerbate the effects of very preterm birth, indicating that preterm birth in itself is the main driver of cardiac changes in these adolescents.