Association Between Preterm Birth and Arrested Cardiac Growth in Adolescents and Young Adults

Right Heart Structure, Geometry and Function Assessed by Echocardiography in 6-Year-Old Children Born Extremely Preterm-A Population-Based Cohort Study

Preterm birth has been associated with altered cardiac phenotype in adults. Our aim was to test the hypothesis that children surviving extremely preterm birth have important structural or functional changes of the right heart or pulmonary circulation. We also examined relations between birth size, gestational age, neonatal diagnoses of bronchopulmonary dysplasia (BPD) and patent ductus arteriosus (PDA) with cardiac outcomes. We assessed a population-based cohort of children born in Sweden before 27 weeks of gestation with echocardiography at 6.5 years of age (n = 176). Each preterm child was matched to a healthy control child born at term. Children born preterm had significantly smaller right atria, right ventricles with smaller widths, higher relative wall thickness and higher estimated pulmonary vascular resistance (PVR) than controls. In preterm children, PVR and right ventricular myocardial performance index (RVmpi’) were significantly higher in those with a PDA as neonates than in those without PDA, but no such associations were found with BPD. In conclusion, children born extremely preterm exhibit higher estimated PVR, altered right heart structure and function compared with children born at term.

Cardiovascular Outcomes in Young Adulthood in a Population-Based Very Low Birth Weight Cohort

OBJECTIVES

To assess differences in left heart structure and function, and endothelial function in a national cohort of very low birth weight (VLBW) young adults and term-born controls.

STUDY DESIGN

The New Zealand VLBW study is a prospective, population-based, longitudinal cohort study which included all infants born <1500 g in 1986. The VLBW cohort (n = 229; 71% of survivors) and term-born controls (n = 100), were assessed at age 26-30 years. Measures of left heart structure and function were evaluated by echocardiography, vascular function was assessed using blood pressure, reactive hyperemia index, and arterioventricular coupling by calculating left ventricular (LV) and arterial elastance.

RESULTS

Compared with controls, those born VLBW had smaller LVs, even when indexed for body surface area (mean LV mass, 89.7 ± 19.3 g/m² vs 95.0 ± 22.3 g/m² [P = .03]; LV end-diastolic volume, 58.3 ± 10.9 mL/m² vs 62.4 ± 12.4 mL/m² [P = .002]; and LV end-systolic volume, 20.8 ± 4.9 mL/m² vs 22.6 ± 5.8 mL/m² [P = .004]). VLBW participants had lower stroke volume (median, 37.2 mL/m² [IQR, 33-42 mL/m²] vs median, 40.1 mL/m² [IQR, 34-45 mL/m²]; P = .0059) and cardiac output (mean, 4.8 ± 1.2 L/min vs 5.1 ± 1.4 L/min; P = .03), but there was no difference in ejection fraction. The VLBW group had higher LV elastance (3.37 ± 0.88 mm Hg/mL vs 2.86 ± 0.75 mm Hg/mL; P < .0001) and arterial elastance (1.84 ± 0.4 vs 1.6 ± 0.4; P < .0001) and lower reactive hyperemia index (0.605 ± 0.28 vs 0.688 ± 0.31; P = .041). These measures were influenced by birth weight and sex, but we found limited associations with other perinatal factors.

CONCLUSIONS

Being born preterm and VLBW is associated with differences in cardiovascular structure and function in adulthood. This population may be more vulnerable to cardiovascular pathology as they age.

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN12612000995875.

Impact of the Vulnerable Preterm Heart and Circulation on Adult Cardiovascular Disease Risk

Preterm birth accounts for over 15 million global births per year. Perinatal interventions introduced since the early 1980s, such as antenatal glucocorticoids, surfactant, and invasive ventilation strategies, have dramatically improved survival of even the smallest, most vulnerable neonates. As a result, a new generation of preterm-born individuals has now reached early adulthood, and they are at increased risk of cardiovascular diseases. To better understand the sequelae of preterm birth, cardiovascular follow-up studies in adolescents and young adults born preterm have focused on characterizing changes in cardiac, vascular, and pulmonary structure and function. Being born preterm associates with a reduced cardiac reserve and smaller left and right ventricular volumes, as well as decreased vascularity, increased vascular stiffness, and higher pressure of both the pulmonary and systemic vasculature. The purpose of this review is to present major epidemiological evidence linking preterm birth with cardiovascular disease; to discuss findings from clinical studies showing a long-term impact of preterm birth on cardiac remodeling, as well as the systemic and pulmonary vascular systems; to discuss differences across gestational ages; and to consider possible driving mechanisms and therapeutic approaches for reducing cardiovascular burden in individuals born preterm.