Preterm Birth Is Associated with Altered Myocardial Function in Infancy

Cardiac biomarkers and left ventricular systolic function in former very preterm infants and term controls at preschool age

Introduction

Due to improvements in perinatal care, survival rates of preterm infants have improved during the last decades. However, these infants remain at risk of developing cardiovascular sequelae later in life. This study aimed to investigate the cardiac biomarkers and left ventricular systolic function in former preterm infants in comparison with term controls at preschool age.

Methods

The study included children aged 5-7 years old born below 32 weeks of gestational age. The control group consisted of same-age children born at term. Basic data of study participants were collected using questionnaires and follow-up databases. During the study visit, we recorded anthropometric data and blood pressure readings, determined high-sensitive cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) concentrations, and calculated fractional shortening (FS) and left ventricular mass (LVM).

Results

Term-born (n = 25; median gestational age, 40.1 weeks) compared with preterm-born infants (n = 80; median gestational age 29.6 weeks) showed no significant differences in the median concentration of hs-cTnT [median, 3.5 (IQR 3.5; 3.5) vs. 3.5 (3.5; 3.5) ng/L, p = 0.328] and the median concentration of NT-pro-BNP [median, 91.0 (IQR 40.8; 150.3) vs. 87.5 (50.1; 189.5) ng/L, p = 0.087]. FS and LVM/LVMI were not significantly different between the two groups.

Conclusion

At preschool age, we observed no significant differences in cardiac biomarkers and left ventricular systolic function in preterm infants. Further studies are warranted to explore the potential of cardiac biomarkers as a prognostic tool for subclinical cardiac alterations after preterm birth.

Left Ventricular Diastolic Function in Subjects Conceived through Assisted Reproductive Technologies

Subjects conceived through assisted reproductive technologies (ART) potentially suffer from impaired left ventricular (LV) function due to premature vascular aging. This study aimed to evaluate whether subtle differences in LV diastolic function can be observed echocardiographically between young ART subjects and their spontaneously conceived peers. The echocardiographic assessment included the measurement of LV dimensions, mitral inflow velocities, and myocardial velocity at early diastole (E', cm/s) at the LV wall and the interventricular septum (IVS). An average from E/E'LV and E/E'IVS (E/E'AVG) was derived. In total, 66 ART subjects and 83 controls (12.85 ± 5.80 years vs. 13.25 ± 5.89 years, p = 0.677) were included. The ART subjects demonstrated a significantly lower E'LV (19.29 ± 3.29 cm/s vs. 20.67 ± 3.78 cm/s, p = 0.020) compared to their spontaneously conceived peers. Study participants of ≥ 10 years of age displayed a significantly higher E/E'AVG (6.50 ± 0.97 vs. 6.05 ± 0.99, p = 0.035) within the ART cohort. The results of this study demonstrate a significantly lower LV diastolic function in the ART subjects. However, no significant changes in LV diastolic function were observed between the two groups when the results were adjusted for age, birth weight percentile, and gestational age. Those ART subjects born preterm might have an elevated risk of developing LV diastolic alterations and could therefore profit from close echocardiographic monitoring.

Linking the Perinatal Environment to Neonatal Cardiovascular Outcomes

Cases of high-risk pregnancies continue to rise throughout the United States and globally, increasing rates of maternal and neonatal morbidity. Common pregnancy complications and morbidities include preterm birth, hypertensive disorders, fetal growth restriction, diabetes mellitus, and chorioamnionitis. Exposure to these perinatal conditions contributes to cardiac morbidities in the fetus and neonate, including altered cardiac growth, congenital heart disease, and cardiac dysfunction. Significant research has demonstrated lasting effects of these pregnancy complications, with increased rates of cardiac morbidities seen in children and adults after these perinatal exposures. The link between the perinatal environment and long-term outcomes has not been fully elucidated. The aim of this review is to discuss the current understanding of the implications of a high-risk pregnancy on fetal and neonatal cardiac development.

Subclinical Changes in Left Heart Structure and Function at Preschool Age in Very Low Birth Weight Preterm Infants

Background

Survivors of preterm birth are at risk of long-term cardiovascular consequences. The objective of this prospective observational study was to assess left heart function at preschool age in preterm children with very low birth weight (VLBW).

Methods

We recruited children aged 5–6 years from preterm infants and full-term children. All subjects underwent conventional echocardiography and speckle-tracking echocardiography. The results were compared between the preterm and term groups.

Results

Eighty-seven VLBW preterm children and 29 term controls were included in the study. After adjusting for body surface area, the preterm group compared to the full-term group had significantly smaller left ventricular (LV) end-diastolic and end-systolic internal dimensions (31.2 vs. 33.5 mm, p = 0.048; and 20.0 vs. 21.6 mm, respectively; p = 0.024), lower LV end-diastolic and end-systolic volumes (38.8 vs. 46.3 mL, p = 0.024; and 12.8 vs. 15.6 mL, respectively; p = 0.008). Left atrial (LA) maximal and minimal volume were also significantly smaller in the preterm group (15.4 vs. 18.9 mL, p = 0.017; and 6.2 vs 7.5 mL, respectively; p = 0.018). LV global longitudinal strain (−21.4 vs. −23.2%, p < 0.0001) and systolic strain rate (−1.30 vs. −1.37 /s, p = 0.001) were significantly lower in the preterm group than in the term control group. LA longitudinal strain was decreased (43.9 vs. 52.8%, p < 0.0001) and left atrial stiffness index (0.17 vs. 0.14, p < 0.0001) was increased in preterm infants. However, all the measurements in both groups were within normal range.

Conclusions

Subclinical changes of left heart structure and function were found in VLBW infants at preschool age. Additional long-term follow-ups of the cardiovascular outcomes are needed in this vulnerable population.

Developmental Differences in Left Ventricular Strain in IUGR vs. Control Children the First Three Months of Life

BACKGROUND

Intrauterine growth restriction (IUGR) may directly affect cardiovascular function in early life. Longitudinal data on left ventricular longitudinal strain (LVLS), a key measure of cardiac function independent of body size, is not available. We hypothesize impaired cardiac function among IUGR newborns and persistence of the impairment until age 3 months.

METHOD

This is a prospective cohort study of consecutive pregnancies where IUGR was identified at 18-38 weeks gestational age (GA) with healthy controls randomly selected at 18-20 weeks GA. Echocardiograms were performed at birth and at age 3-4 months, and then compared.

RESULTS

At birth, mean (SD) LVLS did not differ between the IUGR group [N = 19; - 15.76 (3.12) %] and controls [N = 35; - 15.53 (3.56) %]. The IUGR group demonstrated no significant change in LVLS at age 3-4 months [- 17.80 (3.82) %], while the control group [- 20.91 (3.31) %] showed a significant increase (P < 0.001). Thus, LVLS was lower in the IUGR group at age 3-4 months (P = 0.003).

CONCLUSION

The lack of increase in LVLS may suggest that IUGR has a direct impact on cardiac function as early as during the first months of life. Trial registration Clinical trials.gov Identifier: NCT02583763, registration October 22, 2015. Retrospectively registered September 2014-October 2015, thereafter, registered prospectively.

Intrauterine inflammation exacerbates maladaptive remodeling of the immature myocardium after preterm birth in lambs

BACKGROUND

Antenatal conditions that are linked with preterm birth, such as intrauterine inflammation, can influence fetal cardiac development thereby rendering the heart more vulnerable to the effects of prematurity. We aimed to investigate the effect of intrauterine inflammation, consequent to lipopolysaccharide exposure, on postnatal cardiac growth and maturation in preterm lambs.

METHODS

Preterm lambs (~129 days gestational age) exposed antenatally to lipopolysaccharide or saline were managed according to contemporary neonatal care and studied at postnatal day 7. Age-matched fetal controls were studied at ~136 days gestational age. Cardiac tissue was sampled for molecular analyses and assessment of cardiac structure and cardiomyocyte maturation.

RESULTS

Lambs delivered preterm showed distinct ventricular differences in cardiomyocyte growth and maturation trajectories as well as remodeling of the left ventricular myocardium compared to fetal controls. Antenatal exposure to lipopolysaccharide resulted in further collagen deposition in the left ventricle and a greater presence of immune cells in the preterm heart.

CONCLUSIONS

Adverse impacts of preterm birth on cardiac structure and cardiomyocyte growth kinetics within the first week of postnatal life are exacerbated by intrauterine inflammation. The maladaptive remodeling of the cardiac structure and perturbed cardiomyocyte growth likely contribute to the increased vulnerability to cardiac dysfunction following preterm birth.

IMPACT

Preterm birth induces maladaptive cardiac remodeling and adversely impacts cardiomyocyte growth kinetics within the first week of life in sheep. These effects of prematurity on the heart are exacerbated when preterm birth is preceded by exposure to intrauterine inflammation, a common antecedent of preterm birth. Inflammatory injury to the fetal heart coupled with preterm birth consequently alters neonatal cardiac growth and maturation and thus, may potentially influence long-term cardiac function and health.

Preterm Birth With Neonatal Interventions Accelerates Collagen Deposition in the Left Ventricle of Lambs Without Affecting Cardiomyocyte Development

Background

Adults born preterm (< 37 weeks’ gestation) exhibit altered cardiac growth and are susceptible to cardiac dysfunction. Sheep studies have shown that moderate preterm birth results in maladaptive structural remodelling of the cardiac ventricles. The aim of this study was to examine ventricular structure in lambs born at a greater severity of preterm birth and ventilated postnatally.

Methods

Former-preterm lambs delivered at 128 days’ gestation, and mechanically ventilated for a week after birth, were compared with unventilated lambs born at term (150 days’ gestation), at 2 months (term: n = 10, former-preterm: n = 8), and 5 months (term: n = 9, former-preterm: n = 8) term-equivalent age. The right ventricle and left ventricle plus septum were analysed using immunohistochemistry, histology, and stereology.

Results

Cardiomyocyte number, cross-sectional area, proliferation, and apoptosis were not affected by preterm birth or age. Left ventricle plus septum interstitial collagen levels increased with age (P = 0.0015) and were exacerbated by preterm birth (P = 0.0006; 2 months term: 0.57% ± 0.07%, former-preterm: 1.44% ± 0.18%; 5 months term: 1.37% ± 0.25%, former-preterm: 2.15% ± 0.31%). Right ventricle interstitial collagen levels increased with age (P = 0.012) but were not affected by preterm birth.

Conclusion

This study is the first to explore the effect of preterm birth combined with modern neonatal interventions on the ventricular myocardium in lambs. There was no adverse impact on cardiomyocyte growth in early postnatal life. Of concern, however, there was increased collagen deposition in the preterm hearts, which has the potential to induce cardiac dysfunction, especially if it becomes exaggerated with ageing.

Gestational Hormone Concentrations Are Associated With Timing of Delivery in a Fetal Sex-Dependent Manner

BACKGROUND

Early delivery remains a significant public health problem that has long-lasting impacts on mother and child. Understanding biological mechanisms underlying timing of labor, including endocrine disruption, can inform prevention efforts.

METHODS

Gestational hormones were measured among 976 women in PROTECT, a longitudinal birth cohort in Puerto Rico. We evaluated associations between hormone concentrations at 18 and 26 weeks gestation and gestational age at birth, while assessing effect modification by fetal sex. Exploratory analyses assessed binary outcomes of overall preterm birth (PTB, <37 weeks gestation) and the spontaneous PTB subtype, defined as preterm premature rupture of membranes, spontaneous preterm labor, or both. Multivariable logistic and linear regressions were fit using visit-specific hormone concentrations, and fetal sex-specific effects were estimated using interaction terms. Main outcome models were adjusted for maternal age, education, marital status, alcohol consumption, environmental tobacco smoke exposure, and pre-pregnancy body mass index (BMI). Exploratory models adjusted for maternal age and education.

RESULTS

We observed reduced gestational age at birth with higher circulating CRH (β: -2.73 days, 95% CI: -4.97, -0.42), progesterone (β: -4.90 days, 95% CI: -7.07, -2.73), and fT4 concentrations (β: -2.73 days, 95% CI: -4.76, -0.70) at 18 weeks specifically among male fetuses. Greater odds of overall and spontaneous PTB were observed among males with higher CRH, estriol, progesterone, total triiodothyronine (T3), and free thyroxine (fT4) concentrations. Greater odds of PTB among females was observed with higher testosterone concentrations.

CONCLUSIONS

Various associations between hormones and timing of delivery were modified by fetal sex and timing of hormone measurement. Future studies are needed to understand differential mechanisms involved with timing of labor between fetal sexes.

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.

Microarchitecture of the hearts in term and former-preterm lambs using diffusion tensor imaging

Diffusion tensor imaging (DTI) is an MRI technique that can be used to map cardiomyocyte tracts and estimate local cardiomyocyte and sheetlet orientation within the heart. DTI measures diffusion distances of water molecules within the myocardium, where water diffusion generally occurs more freely along the long axis of cardiomyocytes and within the extracellular matrix, but is restricted by cell membranes such that transverse diffusion is limited. DTI can be undertaken in fixed hearts and it allows the three-dimensional mapping of the cardiac microarchitecture, including cardiomyocyte organization, within the whole heart. The objective of this study was to use DTI to compare the cardiac microarchitecture and cardiomyocyte organization in archived fixed left ventricles of lambs that were born either preterm (n = 5) or at term (n = 7), at a postnatal timepoint equivalent to about 6 years of age in children. Although the findings support the feasibility of retrospective DTI scanning of fixed hearts, several hearts were excluded from DTI analysis because of poor scan quality, such as ghosting artifacts. The preliminary findings from viable DTI scans (n = 3/group) suggest that the extracellular compartment is altered and that there is an immature microstructural phenotype early in postnatal life in the LV of lambs born preterm. Our findings support a potential time-efficient imaging role for DTI in detecting abnormal changes in the microstructure of fixed hearts of former-preterm neonates, although further investigation into factors that affect scan quality is required.

Maturational patterns of left ventricular rotational mechanics in pre-term infants through 1 year of age

BACKGROUND

Pre-mature birth impacts left ventricular development, predisposing this population to long-term cardiovascular risk. The aims of this study were to investigate maturational changes in rotational properties from the neonatal period through 1 year of age and to discern the impact of cardiopulmonary complications of pre-maturity on these measures.

METHODS

Pre-term infants (<29 weeks at birth, n = 117) were prospectively enrolled and followed to 1-year corrected age. Left ventricular basal and apical rotation, twist, and torsion were measured by two-dimensional speckle-tracking echocardiography and analysed at 32 and 36 weeks post-menstrual age and 1-year corrected age. A mixed random effects model with repeated measures analysis was used to compare rotational mechanics over time. Torsion was compared in infants with and without complications of cardiopulmonary diseases of pre-maturity, specifically bronchopulmonary dysplasia, pulmonary hypertension, and patent ductus arteriosus.

RESULTS

Torsion decreased from 32 weeks post-menstrual age to 1-year corrected age in all pre-term infants (p < 0.001). The decline from 32 to 36 weeks post-menstrual age was more pronounced in infants with cardiopulmonary complications, but was similar to healthy pre-term infants from 36 weeks post-menstrual age to 1-year corrected age. The decline was due to directional and magnitude changes in apical rotation over time (p < 0.05).

CONCLUSION

This study tracks maturational patterns of rotational mechanics in pre-term infants and reveals torsion declines from the neonatal period through 1 year. Cardiopulmonary diseases of pre-maturity may negatively impact rotational mechanics during the neonatal period, but the myocardium recovers by 1-year corrected age.

Changes in the Preterm Heart From Birth to Young Adulthood: A Meta-analysis

CONTEXT

Preterm birth is associated with incident heart failure in children and young adults.

OBJECTIVE

To determine the effect size of preterm birth on cardiac remodeling from birth to young adulthood.

DATA SOURCES

Data sources include Medline, Embase, Scopus, Cochrane databases, and clinical trial registries (inception to March 25, 2020).

STUDY SELECTION

Studies in which cardiac phenotype was compared between preterm individuals born at <37 weeks' gestation and age-matched term controls were included.

DATA EXTRACTION

Random-effects models were used to calculate weighted mean differences with corresponding 95% confidence intervals.

RESULTS

Thirty-two observational studies were included (preterm = 1471; term = 1665). All measures of left ventricular (LV) and right ventricular (RV) systolic function were lower in preterm neonates, including LV ejection fraction (P = .01). Preterm LV ejection fraction was similar from infancy, although LV stroke volume index was lower in young adulthood. Preterm LV peak early diastolic tissue velocity was lower throughout development, although preterm diastolic function worsened with higher estimated filling pressures from infancy. RV longitudinal strain was lower in preterm-born individuals of all ages, proportional to the degree of prematurity (R ² = 0.64; P = .002). Preterm-born individuals had persistently smaller LV internal dimensions, lower indexed LV end-diastolic volume in young adulthood, and an increase in indexed LV mass, compared with controls, of 0.71 g/m² per year from childhood (P = .007).

LIMITATIONS

The influence of preterm-related complications on cardiac phenotype could not be fully explored.

CONCLUSIONS

Preterm-born individuals have morphologic and functional cardiac impairments across developmental stages. These changes may make the preterm heart more vulnerable to secondary insults, potentially underlying their increased risk of early heart failure.

Risk factors for adverse events within one year after atrial septal closure in children: a retrospective follow-up study

INTRODUCTION

Secundum atrial septal defect is one of the most common congenital heart defects. Previous paediatric studies have mainly addressed echocardiographic and few clinical factors among children associated with adverse events. The aim of this study was to identify neonatal and other clinical risk factors associated with adverse events up to one year after closure of atrial septal defect.

METHODS

This retrospective case-control study includes children born in Sweden between 2000 and 2014 that were treated surgically or percutaneously for an atrial septal defect. Conditional logistic regression was used to evaluate the association between major and minor adverse events and potential risk factors, adjusting for confounding factors including prematurity, neonatal sepsis, neonatal general ventilatory support, symptomatic atrial septal defects, and pulmonary hypertension.

RESULTS

Overall, 396 children with 400 atrial septal defect closures were included. The median body weight at closure was 14.5 (3.5-110) kg, and the median age was 3.0 (0.1-17.8) years. Overall, 110 minor adverse events and 68 major events were recorded in 87 and 49 children, respectively. Only symptomatic atrial septal defects were associated with both minor (odds ratio (OR) = 2.18, confidence interval (CI) 95% 1.05-8.06) and major (OR = 2.80 CI 95% 1.23-6.37) adverse events.

CONCLUSION

There was no association between the investigated neonatal comorbidities and major or minor events after atrial septal defect closure. Patients with symptomatic atrial septal defects had a two to four times increased risk of having a major event, suggesting careful management and follow-up of these children prior to and after closure.

Predictors of the Need for an Atrial Septal Defect Closure at Very Young Age

An asymptomatic Atrial Septal Defect (ASD) is often closed at the age of 3–5 years using a transcatheter or surgical technique. Symptomatic ASD or ASD associated with pulmonary hypertension (PHT) may require earlier closure, particularly in combination with other non-cardiac risk factors for PHT, but the indications for early closure and the potential risk for complications are largely unknown. The aim of this study was to assess risk factors for needing ASD closure during the first and second years of life. This case-control study included all children treated with surgical or percutaneous ASD closure between 2000 and 2014 at two out of three pediatric heart centers in Sweden. “Cases” were children with ASD closure at ≤1 or ≤2 years of age. Clinical data were retrieved from medical journals and national registries. Overall, 413 children were included. Of these, 131 (32%) were ≤2 years, and 50 (12%) were ≤1 year. Risk factors associated with a ≤2 years ASD closure were preterm birth, OR = 2.4 (95% CI: 1.5–3.9); additional chromosomal abnormalities, OR = 3.4 (95% CI: 1.8–6.5); pulmonary hypertension, OR = 5.8 (95% CI: 2.6–12.6); and additional congenital heart defects, OR = 2.6 (95% CI: 1.7–4.1). These risk associations remained after adjustments for confounding factors, such as need for neonatal respiratory support, neonatal pulmonary diseases, neonatal sepsis, additional congenital heart defects (CHD) and chromosomal abnormalities. ASD size:body weight ratio of 2.0, as well as a ratio of 0.8 (upper and lower limit of the ASD size:body weight ratios), was associated with increased risk of an early ASD closure. Risk factors such as very premature birth, very low birth weight, congenital, and chromosomal abnormalities, neonatal pulmonary disease and need for ventilation support, as well as pulmonary hypertension, were associated with very early (<1 year of age) ASD closure. Several independent neonatal risk factors were associated with an increased risk of early ASD closure at 2 and at 1 year of age. An ASD size:body weight ratio is a poor predictor for indications for ASD closure.

Dilated hypertrophy: a distinct pattern of cardiac remodeling in preterm infants

BACKGROUND

Young adults born preterm have remodeled hearts, i.e., altered cardiac shape and size with impaired cardiac function. At present, the natural history and pattern of prematurity related cardiac remodeling are not clearly established. The aim of this study was to compare the left ventricle (LV) geometry and function of preterm infants at 36 weeks postmenstrual age (PMA) with gestation matched newborn infants.

METHODS

LV end diastolic volume index (LV EDVI), LV mass index (LVMI), relative wall thickness (RWT), and sphericity index (SI) were prospectively obtained with echocardiography. LV geometry was classified according to the Gaasch method. LV function was assessed by determining ejection fraction (EF), longitudinal strain (LS), mitral annulus systolic motion (s'), and estimated LV filling pressure (E/e').

RESULTS

Eighty-three preterm infants between 23 and 29 weeks gestation, and 40 infants of 36 weeks gestation at birth were analysed. LV EDVI, LVMI, SI, LS, s', and E/e' were higher in preterm group while RWT and EF were comparable between groups. LV showed normal geometry in 55.4%, physiological enlargement in 23% and dilated hypertrophy in 21.6% preterm infants.

CONCLUSION

At 36 week, preterm infants have significantly dilated, hypertrophied, and more spherical LV with impaired diastolic function compared with PMA matched newborn infants.

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

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.

Adverse events within 1 year after surgical and percutaneous closure of atrial septal defects in preterm children

INTRODUCTION

Atrial septal defect is the third most common CHD. A hemodynamically significant atrial septal defect causes volume overload of the right side of the heart. Preterm children may suffer from both pulmonary and cardiac comorbidities, including altered myocardial function. The aim of this study was to compare the rate of adverse events following atrial septal defect closure in preterm- and term-born children.

METHOD

We performed a retrospective cohort study including children born in Sweden, who had a surgical or percutaneous atrial septal defect closure at the children's hospitals in Lund and Stockholm, between 2000 and 2014, assessing time to the first event within 1 month or 1 year. We analysed differences in the number of and the time to events between the preterm and term cohort using the Kaplan-Meier survival curve, a generalised model applying zero-inflated Poisson distribution and Gary-Anderson's method.

RESULTS

Overall, 413 children were included in the study. Of these, 93 (22.5%) were born prematurely. The total number of adverse events was 178 (110 minor and 68 major). There was no difference between the cohorts in the number of events, whether within 1 month or within a year, between major (p = 0.69) and minor (p = 0.84) events or frequencies of multiple events (p = 0.92).

CONCLUSION

Despite earlier procedural age, larger atrial septal defects, and higher comorbidity than term children, preterm children appear to have comparable risk for complications during the first year after surgical or percutaneous closure.

Maturational patterns in right ventricular strain mechanics from the fetus to the young infant

AIM

To test the hypothesis that right ventricular (RV) function has age-specific patterns of development, we tracked the evolution of RV strain mechanics by 2D-speckle tracking echocardiography (2DSTE) in healthy subjects from mid-gestation through one year of age.

METHODS

We conducted a prospective longitudinal echocardiography study in 50 healthy subjects at five time periods across gestation (16-20 weeks, 21-25 weeks, 26-30 weeks, 31-35 weeks, and 36-40 weeks) and four time periods following delivery (1 week, 1 month, 6 months, and 1 year of age). We characterized RV function by measuring RV global and free wall longitudinal strain and systolic strain rate, and segmental longitudinal strain at the apical-, mid-, and basal- ventricular levels of the free wall. Possible associations of gestational age, postnatal age, estimated fetal weight, body surface area, gender, and heart rate on strain were investigated.

RESULTS

The magnitudes of RV global and free wall longitudinal strain and global strain rate were decreased throughout gestation (p < 0.05 for all). Following birth, the magnitudes of all measures increased from one week through one year (p < 0.001 for all). RV segmental longitudinal strain maintained a base-to-apex gradient (highest-to-lowest) from mid-gestation through one year (p < 0.001). There was no significant difference in strain patterns based on gender or hear rate.

CONCLUSION

The maturational patterns of RV strain are gestational- and postnatal age- specific. With accepted physiological maturation patterns in healthy subjects, these myocardial deformation parameters can provide a valid basis that allows comparison between health and disease.

Toward the integration of global longitudinal strain analysis in the assessment of neonatal aortic coarctation? A preliminary study

BACKGROUND

Coarctation of the aorta (CoA) is still challenging to diagnose in neonates with patent ductus arteriosus (PDA). Speckle tracking echocardiography allows reliable analysis of myocardial deformation in newborns and seems to provide important insides into regional changes in patients with left ventricular (LV) outflow tract obstruction.

AIMS

To assess the interest of LV global longitudinal strain (GLS) measurement for predicting CoA in neonates with PDA and prenatal suspicion.

METHODS

Prospective single-center study. Twenty-two newborns with prenatal suspicion of CoA were included. All newborns were evaluated in the first 12 hours of life. To assess the feasibility and the reproducibility of GLS, 14 healthy full-term newborns with PDA (group 3) were screened. CoA was diagnosed when DA closed, according to usual echocardiographic criteria.

RESULTS

Six neonates developed CoA after DA closure (group 1) whereas 16 did not (group 2). Mean gestational age and birth weight were not different between the groups. GLS measurements were possible in 100%. Intra- and inter-observer variability of strain measurements was acceptable. GLS values were significantly lower in neonates who developed CoA (P=0.015). To predict CoA, cut-off value of -17.42% gave the best compromise for sensitivity (83%) and specificity (72%). Aortic arch dimensions were modestly correlated with strain values. The presence of a bicuspid aortic valve was not associated with significant lower GLS values.

CONCLUSION

LV GLS analysis is a feasible and reproducible echocardiographic technique in newborns with PDA. Newborns who will develop CoA seem to have lower values of GLS than healthy neonates. Further studies are needed to confirm these preliminary results.

The Preterm Heart in Childhood: Left Ventricular Structure, Geometry, and Function Assessed by Echocardiography in 6-Year-Old Survivors of Periviable Births

BACKGROUND

Preterm birth has been associated with increased risk of cardiovascular morbidity in adult life. We evaluated whether preterm birth is associated with deviating cardiac structure and function before school start.

METHODS AND RESULTS

In total, 176 children aged 6 years and born extremely preterm (EXPT; gestational age of 22-26 weeks) and 134 children born at term (control [CTRL]) were studied. We used echocardiography to assess left heart dimensions, geometry, and functions. Recording and off-line analyses of echocardiographic images were performed by operators blinded to group belonging. Body size, blood pressure, and heart rate were also measured. Rates of family history of cardiovascular disease and sex distribution were similar in the EXPT and CTRL groups. Heart rate and systolic blood pressure did not differ, whereas diastolic blood pressure was slightly higher in EXPT than CTRL participants. After adjusting for body surface area, left ventricular length, width, and aortic valve annulus diameter were 3% to 5% smaller in EXPT than CTRL participants. Left ventricular longitudinal shortening and systolic tissue velocity were 7% to 11% lower, and transversal shortening fraction was 6% higher in EXPT than CTRL participants. The EXPT group also exhibited lower atrial emptying velocities than the CTRL group. Sex, fetal growth restriction, or a patent ductus arteriosus in the neonatal period did not contribute to cardiac dimensions or performance.

CONCLUSIONS

Six-year-old children born extremely preterm exhibit a unique cardiac phenotype characterized by smaller left ventricles with altered systolic and diastolic functions than same-aged children born at term.

Outcomes of Left Ventricular Function According to Treatment Response for a Patent Ductus Arteriosus in Preterm Infants

Background

To evaluate the outcomes of left ventricular (LV) function according to treatment response for a hemodynamically significant patent ductus arteriosus (hsPDA) in preterm infants.

Methods

Echocardiograms of 21 preterm infants born at gestational age < 31 weeks obtained at term-equivalent age were retrospectively studied. Among preterm infants with a hsPDA, 9 underwent ligation after failure of pharmacological closure (ligation group) and 6 experienced successful pharmacological closure (medication group). Six preterm infants without hsPDA (no-hsPDA group) were studied as controls. LV peak longitudinal systolic strain (ε) of each infant was retrospectively obtained from echocardiograms using velocity vector imaging, along with neonatal outcomes.

Results

Pharmacological closures were attempted at postnatal day 2-3. In the ligation group, the median postnatal age at ligation was 20 days. In the ligation group, LV peak longitudinal systolic ε was significantly decreased at term-equivalent age compared to the other groups. Between the medication and no-hsPDA groups, LV peak longitudinal systolic ε did not differ significantly. Among the neonatal outcomes, infants who experienced necrotizing enterocolitis (NEC) showed significantly decreased LV peak longitudinal systolic ε compared to the infants who did not experience NEC .

Conclusion

We speculate that in preterm infants with an hsPDA, in cases of medical treatment failure, early PDA ligation at less than 20 days of postnatal age would be beneficial for preserving LV systolic function.

Application of Neonatologist Performed Echocardiography in the assessment and management of persistent pulmonary hypertension of the newborn

Pulmonary hypertension contributes to morbidity and mortality in both the term newborn infant, referred to as persistent pulmonary hypertension of the newborn (PPHN), and the premature infant, in the setting of abnormal pulmonary vasculature development and arrested growth. In the term infant, PPHN is characterized by the failure of the physiological postnatal decrease in pulmonary vascular resistance that results in impaired oxygenation, right ventricular failure, and pulmonary-to-systemic shunting. The pulmonary vasculature is either maladapted, maldeveloped, or underdeveloped. In the premature infant, the mechanisms are similar in that the early onset pulmonary hypertension (PH) is due to pulmonary vascular immaturity and its underdevelopment, while late onset PH is due to the maladaptation of the pulmonary circulation that is seen with severe bronchopulmonary dysplasia. This may lead to cor-pulmonale if left undiagnosed and untreated. Neonatologist performed echocardiography (NPE) should be considered in any preterm or term neonate that presents with risk factors suggesting PPHN. In this review, we discuss the risk factors for PPHN in term and preterm infants, the etiologies, and the pathophysiological mechanisms as they relate to growth and development of the pulmonary vasculature. We explore the applications of NPE techniques that aid in the correct diagnostic and pathophysiological assessment of the most common neonatal etiologies of PPHN and provide guidelines for using these techniques to optimize the management of the neonate with PPHN.

Deformation imaging and rotational mechanics in neonates: a guide to image acquisition, measurement, interpretation, and reference values

Advances in neonatal cardiac imaging permit a more comprehensive assessment of myocardial performance in neonates that could not be previously obtained with conventional imaging. Myocardial deformation analysis is an emerging quantitative echocardiographic technique to characterize global and regional ventricular function in neonates. Cardiac strain is a measure of tissue deformation and strain rate is the rate at which deformation occurs. These measurements are obtained in neonates using tissue Doppler imaging (TDI) or two-dimensional speckle tracking echocardiography (STE). There is an expanding body of literature describing longitudinal reference ranges and maturational patterns of strain values in term and preterm infants. A thorough understanding of deformation principles, the technical aspects, and clinical applicability is a prerequisite for its routine clinical use in neonates. This review explains the fundamental concepts of deformation imaging in the term and preterm population, describes in a comparative manner the two major deformation imaging methods, provides a practical guide to the acquisition and interpretation of data, and discusses their recognized and developing clinical applications in neonates.

Progression of Right Ventricular Systolic Dysfunction Detected by Myocardial Deformation Imaging in Asymptomatic Preterm Children

Background

To detect progression of right ventricular (RV) systolic dysfunction (RVSD) in asymptomatic preterm children from infancy to 24-month corrected age, using velocity vector imaging (VVI).

Methods

Retrospective study comparing sequential RV longitudinal peak systolic strain (LPSS) from 24 children born at < 33 weeks of gestational age and 10 term infants recruited as controls, obtained at a mean of 4-month (first exam) and 24-month corrected age (second exam).

Results

In 7/24 (29.2%) of preterm children, RV LPSS of < 16%, defined as RVSD, was detected at the second exam; 5/7 of these children had RV LPSS > 16% at the first exam, and only 2/7 of these children had a history of moderate or severe bronchopulmonary dysplasia.

Conclusion

In asymptomatic preterm children, routine echocardiographic screening using VVI could detect RVSD which could progress from 4–24 month corrected age.

Post-transitional adaptation of the left heart in uncomplicated, very preterm infants

BACKGROUND

The postnatal period in preterm infants involves multiple physiological changes occurring immediately after birth and continuing for days or weeks. To recognise and treat compromise, it is important to measure cardiovascular function. The aim of this study was to describe longitudinal left ventricular function using conventional and novel echocardiography techniques in preterm infants who did not experience significant antenatal or postnatal complications and treatments.

METHODS

We prospectively obtained cardiac ultrasound images at days 3, 7, 14, 21, and 28 in 25 uncomplicated, preterm infants <30 weeks of gestation. Speckle tracking analysis of the four chambers and short-axis images provided parameters of left ventricular volume, deformation, and basal myocardial velocities. The patent ductus arteriosus, cardiac dimensions, and atrial volume were also measured.

RESULTS

Stroke volume increased by 24% during the study period (1.05-1.30 ml/kg, p<0.05). Cardiac length, diameter, and systolic basal myocardial velocity increased with unchanged wall stress and deformation parameters. Diastolic function parameters resembled that of the fetus with predominance of atrial contraction compared with early diastolic velocities. Blood pressure and estimates of left ventricular filing pressure increased, suggesting that left ventricular compliance did not change in this period.

CONCLUSION

Stroke volume increased in the first 28 days after preterm birth. The preterm heart adapted by increasing its size, while maintaining systolic and atrial function, independent of early diastolic maturation. Longitudinal deformation of the left ventricle remained unchanged, suggesting relatively preserved function with maturation.

Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle-Tracking Echocardiography in Preterm Infants over the First Year of Age

BACKGROUND

The aim of this study was to determine the maturational changes in systolic ventricular strain mechanics by two-dimensional speckle-tracking echocardiography in extremely preterm neonates from birth to 1 year of age and discern the impact of common cardiopulmonary abnormalities on the deformation measures.

METHODS

In a prospective multicenter study of 239 extremely preterm infants (<29 weeks gestation at birth), left ventricular (LV) global longitudinal strain (GLS) and global longitudinal systolic strain rate (GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricular (RV) free wall longitudinal strain and strain rate, and segmental longitudinal strain in the RV free wall, LV free wall, and IVS were serially measured on days 1, 2, and 5 to 7, at 32 and 36 weeks postmenstrual age, and at 1 year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately.

RESULTS

In uncomplicated preterm infants (n = 103 [48%]), LV GLS and GLSRs remained unchanged from days 5 to 7 to 1 year CA (P = .60 and P = .59). RV free wall longitudinal strain, RV free wall longitudinal strain rate, and IVS GLS and GLSRs significantly increased over the same time period (P < .01 for all measures). A significant base-to-apex (highest to lowest) segmental longitudinal strain gradient (P < .01) was seen in the RV free wall and a reverse apex-to-base gradient (P < .01) in the LV free wall. In infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]), RV free wall longitudinal strain and IVS GLS were significantly lower (P < .01), LV GLS and GLSRs were similar (P = .56), and IVS segmental longitudinal strain persisted as an RV-dominant base-to-apex gradient from 32 weeks postmenstrual age to 1 year CA.

CONCLUSIONS

This study tracks the maturational patterns of global and regional deformation by two-dimensional speckle-tracking echocardiography in extremely preterm infants from birth to 1 year CA. The maturational patterns are ventricular specific. Bronchopulmonary dysplasia and pulmonary hypertension leave a negative impact on RV and IVS strain, while LV strain remains stable.