Persistence of right ventricular dysfunction and altered morphometry in asymptomatic preterm Infants through one year of age: Cardiac phenotype of prematurity

Abstract

Introduction: Prematurity impacts myocardial development and may determine long-term outcomes. The objective of this study was to test the hypothesis that preterm neonates develop right ventricle dysfunction and adaptive remodelling by 32 weeks post-menstrual age that persists through 1 year corrected age.

Materials and methods: A subset of 80 preterm infants (born <29 weeks) was selected retrospectively from a prospectively enrolled cohort and measures of right ventricle systolic function and morphology by two-dimensional echocardiography were assessed at 32 weeks post-menstrual age and at 1 year of corrected age. Comparisons were made to 50 term infants at 1 month and 1 year of age. Sub-analyses were performed in preterm-born infants with bronchopulmonary dysplasia and/or pulmonary hypertension.

Result: In both term and preterm infants, right ventricle function and morphology increased over the first year (p < 0.01). The magnitudes of right ventricle function measures were lower in preterm-born infants at each time period (p < 0.01 for all) and right ventricle morphology indices were wider in all preterm infants by 1 year corrected age, irrespective of lung disease. Measures of a) right ventricle function were further decreased and b) morphology increased through 1 year in preterm infants with bronchopulmonary dysplasia and/or pulmonary hypertension (p < 0.01).

Conclusion: Preterm infants exhibit abnormal right ventricle performance with remodelling at 32 weeks post-menstrual age that persists through 1 year corrected age, suggesting a less developed intrinsic myocardial function response following preterm birth. The development of bronchopulmonary dysplasia and pulmonary hypertension leave a further negative impact on right ventricle mechanics over the first year of age.

Keywords: Right ventricular function; echocardiography; neonates; prematurity; strain imaging.

Conflict of interest statement

Conflicts of Interest: None.

Figures

Figure 1:

Study subject flow diagram.

Figure 2:

Comparison of right ventricle free wall longitudinal systolic strain (A) and strain rate (B) in term and preterm infants at 1 month of age and 1 year of age. * P + P < 0.001 vs. first echocardiogram. **In the preterm-born cohort, echocardiograms were performed at 32 weeks postmenstrual age with a median of 38 days (interquartile range: 33 - 45). In the term-born cohort, echocardiograms were performed at a median of 32 days (interquartile range: 31 - 35). ***In the preterm-born cohort, echocardiograms were performed at 1 year corrected of 494 days (interquartile range: 452 - 521). These numbers reflect actual days of age, but corrected age in days for all preterm infants was a median of 381 days (interquartile range: 355- 424). In the term-born cohort, echocardiograms were performed at a median of 371 days (interquartile range: 365 - 380).

Figure 3:

Comparison of right ventricle segmental longitudinal systolic strain in term and preterm infants at 1 month and 1 year of age. * P + P < 0.001 vs. first echocardiogram. **In the preterm-born cohort, echocardiograms were performed at 32 weeks postmenstrual age with a median of 38 days (interquartile range: 33 - 45). In the term-born cohort, echocardiograms were performed at a median of 32 days (interquartile range: 31 - 35). *** In the preterm-born cohort, echocardiograms were performed at 1 year corrected of 494 days (interquartile range: 452 - 521). These numbers reflect actual days of age, but corrected age in days for all preterm infants was a median of 381 days (interquartile range: 355- 424). In the term-born cohort, echocardiograms were performed at a median of 371 days (interquartile range: 365 - 380).