Right ventricular systolic dysfunction in young adults born preterm

Postexercise Heart Rate Recovery in Adults Born Preterm

OBJECTIVE

To evaluate postexercise heart rate recovery (HRR) in adults born preterm.

STUDY DESIGN

We studied the association between preterm birth and postexercise HRR in 545 adults (267 women) at 23.3 years of age (range 19.9-26.3 years). One hundred three participants were born early preterm (<34 completed weeks), 178 late preterm (34-36), and 264 were full term (control group). HRR was calculated as change in heart rate (HR) 30 seconds and 60 seconds after cessation of submaximal step test and maximum HR slope during the first minute after.

RESULTS

Mean peak HR was 159.5 bpm in the early preterm (P = .16 with controls), 157.8 bpm in the late preterm (P = .56), and 157.0 bpm in the control group. Mean HRR 30 seconds after exercise was 3.2 bpm (95% CI 1.1-5.2) lower in the early preterm group and 2.1 bpm (0.3-3.8) lower in the late preterm group than the full term controls. Mean 60s HRR was 2.5 (-0.1 to 5.1) lower in the early preterm group and 2.8 bpm (0.6-4.9) lower in the late preterm group. Mean maximum slope after exercise was 0.10 beats/s (0.02-0.17) lower in the early preterm group and 0.06 beats/s (0.00-0.12) lower in the late preterm group.

CONCLUSIONS

Our results suggest reduced HRR after exercise in adults born preterm, including those born late preterm. This suggests altered reactivation of the parasympathetic nervous system, which may contribute to cardiovascular risk among adults born preterm.

The Transitional Heart: From Early Embryonic and Fetal Development to Neonatal Life

Formation of the human heart involves complex biological signals, interactions, specification of myocardial progenitor cells, and heart tube looping. To facilitate survival in the hypoxemic intrauterine environment, the fetus possesses structural, physiological, and functional cardiovascular adaptations that are fundamentally different from the neonate. At birth, upon separation from the placental circulation, the neonatal cardiovascular system takes over responsibility of vital processes for survival. The transition from the fetal to neonatal circulation is considered to be a period of intricate physiological, anatomical, and biochemical changes in the cardiovascular system. With a successful cardiopulmonary transition to the extrauterine environment, the fetal shunts are functionally modified or eliminated, enabling independent life. Investigations using medical imaging tools such as ultrasound and magnetic resonance imaging have helped to define normal and abnormal patterns of cardiac remodeling both in utero and ex utero. This has not only allowed for a better understanding of how congenital cardiac malformations alter the hemodynamic transition to the extrauterine environment but also how other more common complications during pregnancy including intrauterine growth restriction, preeclampsia, and preterm delivery adversely affect offspring cardiac remodeling during this early transitional period. This review article describes key cardiac progenitors involved in embryonic heart development; the cellular, physiological, and anatomical changes during the transition from fetal to neonatal circulation; as well as the unique impact that different pregnancy complications have on cardiac remodeling.

Assessment of Right Ventricular Function in the Research Setting: Knowledge Gaps and Pathways Forward. An Official American Thoracic Society Research Statement

BACKGROUND

Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.

METHODS

A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.

RESULTS

This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.

CONCLUSIONS

This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Increased risk of pulmonary hypertension following premature birth

Background

Pulmonary hypertension (PAH) among children and adults has been linked to premature birth, even after adjustments for known risk factors such as congenital heart disease and chronic lung disease. The aim of this population-based registry study was to assess the risk of PAH following exposure to premature birth and other factors in the decades when modern neonatal care was introduced and survival rates increased.

Methods

Data on pulmonary hypertension and perinatal factors were retrieved from population-based governmental and national quality registers. Cases were adults and children over five years of age with pulmonary hypertension born from 1973 to 2010 and individually matched to six controls by birth year and delivery hospital. Conditional multiple logistic regression was performed to assess the risk of pulmonary hypertension following premature birth and to adjust for known confounding factors for the total study population and for time of birth, grouped into five-year intervals.

Results

In total, 128 cases and 768 controls were included in the study group. Preterm birth was over three times more common among cases (21%) than among controls (6%). The overall adjusted risk of pulmonary hypertension was associated with premature birth, OR = 4.48 (95% CI; 2.10–9.53). Maternal hypertension, several neonatal risk factors and female gender were independently associated with PAH when potential confounders were taken into account. For each five-year period, the risk of PAH following premature birth increased several times for children born in the 2000s and later, OR = 17.08 (95% CI 5.60–52.14).

Conclusions

Preterm birth, along with other factors, significantly contributes to PAH. PAH following premature birth has increased over the last few decades. Our study indicates that new, yet unknown factors may play a role in the risk of preterm-born infants developing PAH later in life.

Third Trimester Fetal Cardiac Blood Flow and Cardiac Outcomes in School-Age Children Assessed By Magnetic Resonance Imaging

Background

An adverse fetal environment leads to fetal hemodynamic adaptations with cardiac flow alterations that may subsequently affect cardiac development. We examined the associations of third trimester placental and fetal cardiac hemodynamics with cardiac outcomes in school‐age children.

Methods and Results

We performed a population‐based prospective cohort study among 547 mothers and their children. At a gestational age of 30.4 (95% range 28.4–32.7) weeks, we measured umbilical and cerebral artery resistance, cardiac output, and tricuspid and mitral E/A waves with Doppler. At the median age of 10.0 years (95% range 9.4–11.7) we measured cardiac outcomes with cardiac magnetic resonance imaging. Cardiac outcomes included right ventricular end‐diastolic volume) and right ventricular ejection fraction, left ventricular end diastolic volume and left ventricular ejection fraction, left ventricular mass, and left ventricular mass‐to‐volume ratio as left ventricular mass/left ventricular end diastolic volume. Higher third‐trimester umbilical artery resistance was associated with higher childhood right ventricular ejection fraction (P value <0.05), but not with other cardiac outcomes. The third‐trimester umbilical artery‐cerebral artery pulsatility index ratio was not associated with childhood cardiac outcomes. Higher third‐trimester fetal left cardiac output was associated with lower childhood left ventricular ejection fraction and higher left ventricular mass‐to‐volume ratio (P value <0.05). Third‐trimester fetal right cardiac output was not associated with childhood cardiac outcomes. A higher third‐trimester fetal tricuspid valve E/A ratio was associated with higher childhood right ventricular ejection fraction (P value <0.05).

Conclusions

Our findings suggest that fetal cardiac fetal blood flow redistribution may have long‐term effects on cardiac structure and function. These results should be considered as hypothesis generating and need further replication.

Fetal and infant growth patterns and left and right ventricular measures in childhood assessed by cardiac MRI

OBJECTIVES

Early life is critical for cardiac development. We examined the associations of longitudinal fetal and childhood growth patterns with childhood right and left ventricular structures measured by cardiac magnetic resonance imaging.

METHODS

In a population-based prospective cohort study among 2827 children, we measured growth at 20 and 30 weeks of pregnancy, at birth, 0.5, 1, 2, 6 and 10 years. At 10 years, we measured right ventricular end-diastolic volume, left ventricular end-diastolic volume, left ventricular mass and left ventricular mass-to-volume ratio by cardiac magnetic resonance imaging.

RESULTS

Small size for gestational age at birth was associated with smaller right and left ventricular end-diastolic volume relative to current body surface area, but with larger left ventricular mass-to-volume ratio (P < 0.05). Children in the upper 25% of right and left ventricular end-diastolic volume and left ventricular mass at age 10 years were larger at birth and became taller and leaner in childhood (P < 0.05). In contrast, children in the lower 25% of right and left ventricular end-diastolic volume and left ventricular mass were smaller at birth and became shorter and heavier in childhood (P < 0.05). Both fetal and childhood growth were independently of each other associated with childhood right and left ventricular end-diastolic volume and left ventricular mass.

CONCLUSION

Children who are larger at birth and grow taller and leaner in childhood have larger hearts relative to body surface area. Small size at birth children, who grow shorter and heavier in childhood, have relatively smaller hearts with larger left ventricular mass-to-volume ratio. Both fetal and childhood growth are important for the development of cardiac dimensions.

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.

Preterm Birth as a Risk Factor for Metabolic Syndrome and Cardiovascular Disease in Adult Life: A Systematic Review and Meta-Analysis

OBJECTIVE

To determine if preterm birth is associated with components of the metabolic syndrome in adult life.

STUDY DESIGN

A structured literature search was performed using PubMed. All comparative studies reported metabolic and cardiovascular outcomes in adults (≥18 years of age) born preterm (<37 weeks of gestation) compared with adults born at term (37-42 weeks of gestation) and published through March 2018 were included. The major outcomes assessed were body mass index, waist circumference, waist-to-hip ratio, fat mass, systolic blood pressure (SBP), diastolic blood pressure (DBP), 24-hour SBP, 24-hour DBP, endothelium-dependent brachial artery flow-mediated dilation, carotid intima-media thickness, pulse wave velocity, fasting glucose and insulin, Homeostasis Model Assessment-Estimated Insulin Resistance Index, and lipid profiles. Quality appraisal was performed using a modified version of the Newcastle-Ottawa scale. A meta-analysis was performed for comparable studies which reported sufficient data.

RESULTS

Forty-three studies were included, including a combined total of 18 295 preterm and 294 063 term-born adults. Prematurity was associated with significantly higher fat mass (P = .03), SBP (P < .0001), DBP (P < .0001), 24-hour SBP (P < .001), and 24-hour DBP (P < .001). Furthermore, preterm-born adults presented higher values of fasting glucose (P = .01), insulin (P = .002), Homeostasis Model Assessment-Estimated Insulin Resistance Index (P = .05), and total cholesterol levels (P = .05) in comparison with adults born at term, in random effect models. No statistically significant difference was found between preterm and term-born adults for the other outcomes studied.

CONCLUSIONS

Preterm birth is strongly associated with a number of components of the metabolic syndrome and cardiovascular disease in adult life.

Serial Changes in Right Ventricular Systolic Function Among Rejection-Free Children and Young Adults After Heart Transplantation

BACKGROUND

Evolution of right ventricular (RV) systolic function after pediatric heart transplantation (HT) has not been well described.

METHODS

We analyzed echocardiograms performed over the first year after HT among children and young adults who remained rejection-free. Ninety-six patients (median age 7.1 [0.1-24.4] years at HT) were included: 22 infants (≤1 year) and 74 noninfants (>1 year). Two-dimensional tricuspid annular plane systolic excursion (TAPSE), tissue Doppler-derived tricuspid annular systolic velocity (S'), fractional area change (FAC), myocardial performance index (MPI), and two-dimensional speckle-tracking-derived RV global longitudinal (GLS) and free wall strain (FWS) were assessed.

RESULTS

All measures of RV function were impaired immediately after HT and significantly improved over the first year: TAPSE z-score (-8.15 ± 1.88 to -3.94 ± 1.65, P < .0001), S' z-score (-4.30 ± 1.36 to -2.28 ± 1.33, P < .0001), FAC (24.37% ± 7.71% to 42.02% ± 7.09%, P < .0001), MPI (0.96 ± 0.47 to 0.41 ± 0.22, P < .0001), GLS (-10.37% ± 3.86% to -21.05% ± 3.41%, P < .0001), and FWS (-11.2% ± 4.08% to -23.66% ± 4.13%, P < .0001). By 1 year post-HT, TAPSE, S', GLS, and FWS, remained abnormal, whereas FAC and MPI nearly normalized. Patients transplanted during infancy demonstrated better recovery of RV systolic function.

CONCLUSIONS

Although RV systolic function improved over the first year after HT in children and young adults without rejection, measures that assess longitudinal contractility remained abnormal at 1 year post-HT. These findings contribute to our understanding of RV myocardial contractility after HT in children and young adults and improve our ability to assess function quantitatively in this population.

Ventricular remodeling in preterm infants: computational cardiac magnetic resonance atlasing shows significant early remodeling of the left ventricle

BACKGROUND

Premature birth is associated with ventricular remodeling, early heart failure, and altered left ventricular (LV) response to physiological stress. Using computational cardiac magnetic resonance (CMR) imaging, we aimed to quantify preterm ventricular remodeling in the neonatal period, and explore contributory clinical factors.

METHODS

Seventy-three CMR scans (34 preterm infants, 10 term controls) were performed to assess in-utero development and preterm ex-utero growth. End-diastolic computational atlases were created for both cardiac ventricles; t statistics, linear regression modeling, and principal component analysis (PCA) were used to describe the impact of prematurity and perinatal factors on ventricular volumetrics, ventricular geometry, myocardial mass, and wall thickness.

RESULTS

All preterm neonates demonstrated greater weight-indexed LV mass and higher weight-indexed end-diastolic volume at term-corrected age (P < 0.05 for all preterm gestations). Independent associations of increased term-corrected age LV myocardial wall thickness were (false discovery rate <0.05): degree of prematurity, antenatal glucocorticoid administration, and requirement for >48 h postnatal respiratory support. PCA of LV geometry showed statistical differences between all preterm infants at term-corrected age and term controls.

CONCLUSIONS

Computational CMR demonstrates that significant LV remodeling occurs soon after preterm delivery and is associated with definable clinical situations. This suggests that neonatal interventions could reduce long-term cardiac dysfunction.

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.

Postnatal undernutrition alters adult female mouse cardiac structure and function leading to limited exercise capacity

KEY POINTS

Impaired growth during fetal life can reprogramme heart development and increase the risk for long-term cardiovascular dysfunction. It is uncertain if the developmental window during which the heart is vulnerable to reprogramming as a result of inadequate nutrition extends into the postnatal period. We found that adult female mice that had been undernourished only from birth to 3 weeks of age had disproportionately smaller hearts compared to males, with thinner ventricle walls and more mononucleated cardiomyocytes. In females, but not males, cardiac diastolic function, and heart rate responsiveness to adrenergic stimulation were limited and maximal exercise capacity was compromised. These data suggest that the developmental window during which the heart is vulnerable to reprogramming by inadequacies in nutrient intake may extend into postnatal life and such individuals could be at increased risk for a cardiac event as a result of strenuous exercise.

ABSTRACT

Adults who experienced undernutrition during critical windows of development are at increased risk for cardiovascular disease. The contribution of cardiac function to this increased disease risk is uncertain. We evaluated the effect of a short episode of postnatal undernutrition on cardiovascular function in mice at the whole animal, organ, and cellular levels. Pups born to control mouse dams were suckled from birth to postnatal day (PN) 21 on dams fed either a control (20% protein) or a low protein (8% protein) isocaloric diet. After PN21 offspring were fed the same control diet until adulthood. At PN70 V ̇ O 2 , max was measured by treadmill test. At PN80 cardiac function was evaluated by echocardiography and Doppler analysis at rest and following β-adrenergic stimulation. Isolated cardiomyocyte nucleation and Ca²⁺ transients (with and without β-adrenergic stimulation) were measured at PN90. Female mice that were undernourished and then refed (PUN), unlike male mice, had disproportionately smaller hearts and their exercise capacity, cardiac diastolic function, and heart rate responsiveness to adrenergic stimulation were limited. A reduced left ventricular end diastolic volume, impaired early filling, and decreased stored energy at the beginning of diastole contributed to these impairments. Female PUN mice had more mononucleated cardiomyocytes; under resting conditions binucleated cells had a functional profile suggestive of increased basal adrenergic activation. Thus, a brief episode of early postnatal undernutrition in the mouse can produce persistent changes to cardiac structure and function that limit exercise/functional capacity and thereby increase the risk for the development of a wide variety of cardiovascular morbidities.

Preventing bronchopulmonary dysplasia: new tools for an old challenge

Bronchopulmonary dysplasia (BPD) is the most prevalent chronic lung disease in infants and presents as a consequence of preterm birth. Due to the lack of effective preventive and treatment strategies, BPD currently represents a major therapeutic challenge that requires continued research efforts at the basic, translational, and clinical levels. However, not all very low birth weight premature babies develop BPD, which suggests that in addition to known gestational age and intrauterine and extrauterine risk factors, other unknown factors must be involved in this disease's development. One of the main goals in BPD research is the early prediction of very low birth weight infants who are at risk of developing BPD in order to initiate the adequate preventive strategies. Other benefits of determining the risk of BPD include providing prognostic information and stratifying infants for clinical trial enrollment. In this article, we describe new opportunities to address BPD's complex pathophysiology by identifying prognostic biomarkers and develop novel, complex in vitro human lung models in order to develop effective therapies. These therapies for protecting the immature lung from injury can be developed by taking advantage of recent scientific progress in -omics, 3D organoids, and regenerative medicine.

Preterm Birth Is a Novel, Independent Risk Factor for Altered Cardiac Remodeling and Early Heart Failure: Is it Time for a New Cardiomyopathy?

PURPOSE OF REVIEW

Around 10% of the global population is born preterm (< 37 weeks' gestation). Preterm birth is associated with an increased risk of cardiovascular events, with preterm-born individuals demonstrating a distinct cardiac phenotype. This review aims to summarize the main phenotypic features of the preterm heart and directions for future research to develop novel intervention strategies.

RECENT FINDINGS

Being born between 28 and 31 weeks' gestation results in a 4-fold higher risk of heart failure in childhood and adolescence and 17-fold increased risk when born less than 28 weeks' gestation. In support of this being due to a reduction in myocardial functional reserve, preterm-born young adults have an impaired left ventricular cardiac systolic response to moderate and high intensity physiological stress, despite having a preserved resting left ventricular ejection fraction. Similar impairments under physiological stress were also recently reported regarding the right ventricle in young adults born preterm. Preterm birth relates to a unique cardiac phenotype with an impaired response to stress conditions. These data, combined with the work in animal models, suggest that being born preterm may lead to a novel form of cardiomyopathy. Understanding the driving mechanisms leading to this unique cardiac phenotype is important to reduce risk of future heart failure and cardiovascular events.

Fetal programming and the angiotensin-(1-7) axis: a review of the experimental and clinical data

Hypertension is the primary risk factor for cardiovascular disease that constitutes a serious worldwide health concern and a significant healthcare burden. As the majority of hypertension has an unknown etiology, considerable research efforts in both experimental models and human cohorts has focused on the premise that alterations in the fetal and perinatal environment are key factors in the development of hypertension in children and adults. The exact mechanisms of how fetal programming events increase the risk of hypertension and cardiovascular disease are not fully elaborated; however, the focus on alterations in the biochemical components and functional aspects of the renin-angiotensin (Ang) system (RAS) has predominated, particularly activation of the Ang-converting enzyme (ACE)-Ang II-Ang type 1 receptor (AT1R) axis. The emerging view of alternative pathways within the RAS that may functionally antagonize the Ang II axis raise the possibility that programming events also target the non-classical components of the RAS as an additional mechanism contributing to the development and progression of hypertension. In the current review, we evaluate the potential role of the ACE2-Ang-(1-7)-Mas receptor (MasR) axis of the RAS in fetal programming events and cardiovascular and renal dysfunction. Specifically, the review examines the impact of fetal programming on the Ang-(1-7) axis within the circulation, kidney, and brain such that the loss of Ang-(1-7) expression or tone, contributes to the chronic dysregulation of blood pressure (BP) and cardiometabolic disease in the offspring, as well as the influence of sex on potential programming of this pathway.

Heart rate recovery after maximal exercise is impaired in healthy young adults born preterm

PURPOSE

The long-term implications of premature birth on autonomic nervous system (ANS) function are unclear. Heart rate recovery (HRR) following maximal exercise is a simple tool to evaluate ANS function and is a strong predictor of cardiovascular disease. Our objective was to determine whether HRR is impaired in young adults born preterm (PYA).

METHODS

Individuals born between 1989 and 1991 were recruited from the Newborn Lung Project, a prospectively followed cohort of subjects born preterm weighing < 1500 g with an average gestational age of 28 weeks. Age-matched term-born controls were recruited from the local population. HRR was measured for 2 min following maximal exercise testing on an upright cycle ergometer in normoxia and hypoxia, and maximal aerobic capacity (VO_2max) was measured.

RESULTS

Preterms had lower VO_2max than controls (34.88 ± 5.24 v 46.15 ± 10.21 ml/kg/min, respectively, p < 0.05), and exhibited slower HRR compared to controls after 1 and 2 min of recovery in normoxia (absolute drop of 20 ± 4 v 31 ± 10 and 41 ± 7 v 54 ± 11 beats per minute (bpm), respectively, p < 0.01) and hypoxia (19 ± 5 v 26 ± 8 and 39 ± 7 v 49 ± 13 bpm, respectively, p < 0.05). After adjusting for VO_2max, HRR remained slower in preterms at 1 and 2 min of recovery in normoxia (21 ± 2 v 30 ± 2 and 42 ± 3 v 52 ± 3 bpm, respectively, p < 0.05), but not hypoxia (19 ± 3 v 25 ± 2 and 40 ± 4 v 47 ± 3 bpm, respectively, p > 0.05).

CONCLUSIONS

Autonomic dysfunction as seen in this study has been associated with increased rates of cardiovascular disease in non-preterm populations, suggesting further study of the mechanisms of autonomic dysfunction after preterm birth.

Clinical applications of feature-tracking cardiac magnetic resonance imaging

Cardiovascular diseases represent the leading cause of mortality and morbidity in the western world. Assessment of cardiac function is pivotal for early diagnosis of primitive myocardial disorders, identification of cardiac involvement in systemic diseases, detection of drug-related cardiac toxicity as well as risk stratification and monitor of treatment effects in patients with heart failure of various etiology. Determination of ejection fraction with different imaging modalities currently represents the gold standard for evaluation of cardiac function. However, in the last few years, cardiovascular magnetic resonance feature tracking techniques has emerged as a more accurate tool for quantitative evaluation of cardiovascular function with several parameters including strain, strain-rate, torsion and mechanical dispersion. This imaging modality allows precise quantification of ventricular and atrial mechanics by directly evaluating myocardial fiber deformation. The purpose of this article is to review the basic principles, current clinical applications and future perspectives of cardiovascular magnetic resonance myocardial feature tracking, highlighting its prognostic implications.

Right ventricular function in infants with bronchopulmonary dysplasia and pulmonary hypertension: a pilot study

Premature birth and bronchopulmonary dysplasia (BPD) are risk factors for the development of echocardiographic signs of pulmonary hypertension (PH) and are associated with changes in cardiac structure and function. It is unclear whether this association persists beyond early infancy. The aims of this study are to prospectively investigate the prevalence of PH in children with severe BPD and to investigate the effect of BPD and PH on myocardial structure and function at six months corrected age. Preterm infants (gestational age ≤ 32 weeks) with severe BPD were included. Echocardiography was used to define PH and to measure speckle tracking derived longitudinal and circumferential strain of the left ventricle (LV) and right ventricle (RV). Sixty-nine infants with a median (interquartile range [IQR]) gestational age of 25.6 (24.9–26.4) weeks and a median birthweight of 770 (645–945) gram were included. Eight (12%) infants had signs of PH at six months corrected age. RV fractional area change was lower in infants with severe BPD and PH at six months compared to infants without PH (35% ± 9% vs. 43% ± 9%, P = 0.03). RV mean longitudinal systolic strain was lower in infants with severe BPD and PH compared to infants without PH (17.6% [−19.5%/−16.1%] vs. −20.9% [−25.9%/−17.9%], P = 0.04). RV size and LV longitudinal and circumferential strain in children with BPD with or without PH were similar. Signs of PH were found in 12% of infants with severe BPD at six months corrected age and the presence of PH is associated with reduced RV systolic function.

Trial of exercise to prevent HypeRtension in young adults (TEPHRA) a randomized controlled trial: study protocol

Background

Hypertension prevalence in young adults has increased and is associated with increased incidence of cerebrovascular and cardiovascular events in middle age. However, there is significant debate regards how to effectively manage young adult hypertension with recommendation to target lifestyle intervention. Surprisingly, no trials have investigated whether lifestyle advice developed for blood pressure control in older adults is effective in these younger populations.

Methods/Design

TEPHRA is an open label, parallel arm, randomised controlled trial in young adults with high normal and elevated blood pressure. The study will compare a supervised physical activity intervention consisting of 16 weeks structured exercise, physical activity self-monitoring and motivational coaching with a control group receiving usual care/minimal intervention. Two hundred young adults aged 18–35 years, including a subgroup of preterm born participants will be recruited through open recruitment and direct invitation. Participants will be randomised in a ratio of 1:1 to either the exercise intervention group or control group. Primary outcome will be ambulatory blood pressure monitoring at 16 weeks with measure of sustained effect at 12 months. Study measures include multimodal cardiovascular assessments; peripheral vascular measures, blood sampling, microvascular assessment, echocardiography, objective physical activity monitoring and a subgroup will complete multi-organ magnetic resonance imaging.

Discussion

The results of this trial will deliver a novel, randomised control trial that reports the effect of physical activity intervention on blood pressure integrated with detailed cardiovascular phenotyping in young adults. The results will support the development of future research and expand the evidence-based management of blood pressure in young adult populations.

Trial Registration

Clinicaltrials.gov registration number NCT02723552, registered on 30 March, 2016.

Endothelial colony-forming cell therapy for heart morphological changes after neonatal high oxygen exposure in rats, a model of complications of prematurity

Very preterm birth is associated with increased cardiovascular diseases and changes in myocardial structure. The current study aimed to investigate the impact of endothelial colony-forming cell (ECFC) treatment on heart morphological changes in the experimental model of neonatal high oxygen (O2 )-induced cardiomyopathy, mimicking prematurity-related conditions. Sprague-Dawley rat pups exposed to 95% O2 or room air (RA) from day 4 (P4) to day 14 (P14) were randomized to receive (jugular vein) exogenous human cord blood ECFC or vehicle at P14 (n = 5 RA-vehicle, n = 8 RA-ECFC, n = 8 O2 -vehicle and n = 7 O2 -ECFC) and the hearts collected at P28. Body and heart weights and heart to body weight ratio did not differ between groups. ECFC treatment prevented the increase in cardiomyocyte surface area in both the left (LV) and right (RV) ventricles of the O2 group (O2 -ECFC vs. O2 -vehicle LV: 121 ± 13 vs. 179 ± 21 μm2 , RV: 118 ± 12 vs. 169 ± 21 μm2 ). In O2 rats, ECFC treatment was also associated with a significant reduction in interstitial fibrosis in both ventricles (O2 -ECFC vs. O2 -vehicle LV: 1.07 ± 0.47 vs. 1.68 ± 0.41% of surface area, RV: 1.01 ± 0.74 vs. 1.77 ± 0.67%) and in perivascular fibrosis in the LV (2.29 ± 0.47 vs. 3.85 ± 1.23%) but in not the RV (1.95 ± 0.95 vs. 2.74 ± 1.14), and with increased expression of angiogenesis marker CD31. ECFC treatment had no effect on cardiomyocyte surface area or on tissue fibrosis of RA rats. Human cord blood ECFC treatment prevented cardiomyocyte hypertrophy and myocardial and perivascular fibrosis observed after neonatal high O2 exposure. ECFC could constitute a new regenerative therapy against cardiac sequelae caused by deleterious conditions of prematurity.

Perioperative Factors Influence the Long-Term Outcomes of Children and Adolescents with Repaired Tetralogy of Fallot

Tetralogy of Fallot (TOF) often carries long-term seqüelae following surgical intervention. We hypothesized that early perioperative factors are associated with long-term adverse right ventricular (RV) remodeling, diminished exercise capacity, and increased morbidity. We conducted a retrospective cohort study of patients operated for TOF that underwent cardiac magnetic resonance imaging study (CMR), exercise stress test (EST), and detailed review of past medical history. Outcome variables included measures of RV size, and function, maximal work rate, and oxygen consumption, and interim hospitalizations, surgeries, and catheterizations. Thirty-nine subjects were included. Age at surgical repair was 0.3 ± 0.3 years and age at testing was 9.7 ± 1.4 years. On CMR, there was borderline RV dilation with moderate pulmonary insufficiency (PI) [RF 32% (8; 43)] and normal RV ejection fraction [60% (55; 67)]. On EST, there was low percent-predicted maximal oxygen consumption (77 ± 20%), and percent-predicted maximal work rate (84 ± 23%). On multivariable analysis, mechanical ventilation and Blalock-Taussig (BT) shunt prior to complete surgical repair were associated with the number of future hospitalizations. Duration of cardiopulmonary bypass and prior BT shunt were associated with future catheterizations. Prior BT shunt was a predictor of worse RVEF, while duration of mechanical ventilation and use of transannular patch were predictors of worse PI. Longer duration of mechanical ventilation (or LOS) was associated with worse maximal work rate. Surgical and perioperative factors may portend long-term RV remodeling and outcome in TOF. Further studies are warranted to explore these associations and potential underlying mechanisms.

Long-term pulmonary vascular consequences of perinatal insults

Development of the pulmonary circulation is a critical component of fetal lung development, and continues throughout infancy and childhood, marking an extended window of susceptibility to vascular maldevelopment and maladaptation. Perinatal vascular insults may result in abnormal vascular structure or function, including decreased angiogenic signaling and vascular endowment, impaired vasoreactivity through increased pulmonary artery endothelial dysfunction and remodeling, or enhanced genetic susceptibility to pulmonary vascular disease through epigenetic modifications or germline mutations. Although some infants develop early onset pulmonary hypertension, due to the unique adaptive capabilities of the immature host many do not have clinically evident early pulmonary vascular dysfunction. These individuals remain at increased risk for development of late-onset pulmonary hypertension, and may be particularly susceptible to secondary insults. This review will address the role of perinatal vascular insults in the development of late pulmonary vascular dysfunction with an effort to highlight areas of critical research need.

Endothelial Colony-Forming Cells in Young Adults Born Preterm: A Novel Link Between Neonatal Complications and Adult Risks for Cardiovascular Disease

BACKGROUND

Preterm birth is linked to cardiovascular risks and diseases. Endothelial progenitor cells play a critical role in vascular development and repair. Cord blood endothelial progenitor cells of preterm-born infants, especially endothelial colony-forming cells (ECFC), show enhanced susceptibility to prematurity-related pro-oxidant stress. Whether ECFC dysfunction is present in adulthood following preterm birth is unknown.

METHODS AND RESULTS

This cross-sectional observational study includes 55 preterm-born (≤29 gestational weeks) young adults (18-29 years old, 38% male) and 55 sex- and age-matched full-term controls. ECFC were isolated from peripheral blood; cell proliferative and vascular cord formation capacities were assessed in vitro. Daytime systolic blood pressure was higher, whereas glucose tolerance and body mass index were lower in preterm-born subjects. ECFC colonies grew in culture for 62% of full-term- and 58% of preterm-born participants. Preterm-born participants have formed ECFC colonies later in culture and have reduced proliferation compared with controls. Only in preterm-born individuals, we observed that the later the ECFC colony grows in culture, the worse was overall ECFC function. In addition, in preterms, elevated systolic blood pressure significantly correlated with reduced ECFC proliferation (r_S=-0.463; P=0.030) and numbers of branches formed on matrigel (r_S=-0.443; P=0.039). In preterm-born subjects, bronchopulmonary dysplasia was associated with impaired ECFC function, whereas exposure to antenatal steroids related to better ECFC function.

CONCLUSIONS

This study is the first to examine ECFC in preterm-born adults and to demonstrate ECFC dysfunction compared with full-term controls. In the preterm-born group, ECFC dysfunction was associated with bronchopulmonary dysplasia, the major prematurity-related neonatal morbidity, and with increased systolic blood pressure into adulthood.

Neonatal autonomic function after pregnancy complications and early cardiovascular development

BACKGROUND

Heart rate variability (HRV) has emerged as a predictor of later cardiac risk. This study tested whether pregnancy complications that may have long-term offspring cardiac sequelae are associated with differences in HRV at birth, and whether these HRV differences identify abnormal cardiovascular development in the postnatal period.

METHODS

Ninety-eight sleeping neonates had 5-min electrocardiogram recordings at birth. Standard time and frequency domain parameters were calculated and related to cardiovascular measures at birth and 3 months of age.

RESULTS

Increasing prematurity, but not maternal hypertension or growth restriction, was associated with decreased HRV at birth, as demonstrated by a lower root mean square of the difference between adjacent NN intervals (rMSSD) and low (LF) and high-frequency power (HF), with decreasing gestational age (p < 0.001, p = 0.009 and p = 0.007, respectively). We also demonstrated a relative imbalance between sympathetic and parasympathetic tone, compared to the term infants. However, differences in autonomic function did not predict cardiovascular measures at either time point.

CONCLUSIONS

Altered cardiac autonomic function at birth relates to prematurity rather than other pregnancy complications and does not predict cardiovascular developmental patterns during the first 3 months post birth. Long-term studies will be needed to understand the relevance to cardiovascular risk.

Prenatal exposure to preeclampsia as an independent risk factor for long-term cardiovascular morbidity of the offspring

INTRODUCTION

Preeclampsia is a leading cause of maternal and fetal morbidity and mortality. Regarding the offspring, little is known about the long-term complications. The objective of the current study is to assess whether in utero exposure to preeclampsia increases the risk of long-term cardiovascular morbidity in the offspring.

MATERIALS AND METHODS

A population-based cohort study compared the incidence of cardiovascular disease between singletons exposed and unexposed to preeclampsia. Deliveries occurred between 1991 and 2014 in a regional tertiary medical center. A Cox proportional hazard model was used to control for confounders.

RESULTS

During the study period 231,298 deliveries met the inclusion criteria; 4.1% of the births were to mothers diagnosed with preeclampsia, of which 3.2% with mild preeclampsia (n = 7286), 0.9% with severe preeclampsia (n = 2174) and 0.03% with eclampsia (n = 73). A significant linear association was noted between preeclampsia (no preeclampsia, mild preeclampsia, severe preeclampsia and eclampsia) and cardiovascular disease of the offspring (0.24%, vs. 0.33% vs. 0.51% vs. 2.73% respectively, p < 0.001 using the chi-square test for trends). In the offspring born at term, severe preeclampsia was found to be an independent risk factor for cardiovascular morbidity (adjusted HR = 2.32; 95% CI 1.15-4.67). In offspring born preterm, neither severe preeclampsia (adjusted HR = 1.36; 95% CI 0.53-3.48) nor mild preeclampsia (adjusted HR = 0.37; 95% CI 0.52-2.71) were associated with cardiovascular morbidity of the offspring.

CONCLUSION

Exposure to severe maternal preeclampsia is an independent risk factor for long-term cardiovascular morbidity in the offspring born at term.

Moderate preterm birth affects right ventricular structure and function and pulmonary artery blood flow in adult sheep

KEY POINTS

Preterm birth occurs when the heart muscle is immature and ill-prepared for the changes in heart and lung function at birth. MRI imaging studies show differences in the growth and function of the heart of young adults born preterm, with the effects more pronounced in the right ventricle. The findings of this study, conducted in sheep, showed that following moderate preterm birth the right ventricular wall was thinner in adulthood, with a reduction in the number and size of the heart muscle cells; in addition, there was impaired blood flow in the main artery leading from the right ventricle to the lungs. The findings indicate that being born only a few weeks early adversely affects the cellular structure of the right ventricle and blood flow to the lungs in adulthood. The reduced number of heart muscle cells has the potential to deleteriously affect right ventricular growth potential and function.

ABSTRACT

Preterm birth prematurely exposes the immature heart to the haemodynamic transition at birth, which has the potential to induce abnormal cardiac remodelling. Magnetic resonance imaging studies in young adults born preterm have shown abnormalities in the gross structure of the ventricles (particularly the right ventricle; RV), but the cellular basis of these alterations is unknown. The aim of this study, conducted in sheep, was to determine the effect of moderate preterm birth on RV cellular structure and function in early adulthood. Male singleton lambs were delivered moderately preterm (132 ± 1 days; n = 7) or at term (147 ± 1 days; n = 7). At 14.5 months of age, intra-arterial blood pressure and heart rate were measured. Pulmonary artery diameter and peak systolic blood flow were determined using ultrasound imaging, and RV stroke volume and output calculated. Cardiomyocyte number, size, nuclearity and levels of cardiac fibrosis were subsequently assessed in perfusion-fixed hearts using image analysis and stereological methods. Blood pressure (systolic, diastolic and mean), heart rate, levels of myocardial fibrosis and RV stroke volume and output were not different between groups. There was, however, a significant reduction in RV wall thickness in preterm sheep, and this was accompanied by a significant reduction in peak systolic blood flow in the pulmonary artery and in RV cardiomyocyte number. Cellular changes in the RV wall and reduced pulmonary artery blood flow following preterm birth have the potential to adversely affect cardiac and respiratory haemodynamics, especially when the cardiovascular system is physiologically or pathologically challenged.

Evidence of cardiac involvement in the fetal inflammatory response syndrome: disruption of gene networks programming cardiac development in nonhuman primates

BACKGROUND

Most early preterm births are associated with intraamniotic infection and inflammation, which can lead to systemic inflammation in the fetus. The fetal inflammatory response syndrome describes elevations in the fetal interleukin-6 level, which is a marker for inflammation and fetal organ injury. An understanding of the effects of inflammation on fetal cardiac development may lead to insight into the fetal origins of adult cardiovascular disease.

OBJECTIVE

The purpose of this study was to determine whether the fetal inflammatory response syndrome is associated with disruptions in gene networks that program fetal cardiac development.

STUDY DESIGN

We obtained fetal cardiac tissue after necropsy from a well-described pregnant nonhuman primate model (pigtail macaque, Macaca nemestrina) of intrauterine infection (n=5) and controls (n=5). Cases with the fetal inflammatory response syndrome (fetal plasma interleukin-6 >11 pg/mL) were induced by either choriodecidual inoculation of a hypervirulent group B streptococcus strain (n=4) or intraamniotic inoculation of Escherichia coli (n=1). RNA and protein were extracted from fetal hearts and profiled by microarray and Luminex (Millipore, Billerica, MA) for cytokine analysis, respectively. Results were validated by quantitative reverse transcriptase polymerase chain reaction. Statistical and bioinformatics analyses included single gene analysis, gene set analysis, Ingenuity Pathway Analysis (Qiagen, Valencia, CA), and Wilcoxon rank sum.

RESULTS

Severe fetal inflammation developed in the context of intraamniotic infection and a disseminated bacterial infection in the fetus. Interleukin-6 and -8 in fetal cardiac tissues were elevated significantly in fetal inflammatory response syndrome cases vs controls (P<.05). A total of 609 probe sets were expressed differentially (>1.5-fold change, P<.05) in the fetal heart (analysis of variance). Altered expression of select genes was validated by quantitative reverse transcriptase polymerase chain reaction that included several with known functions in cardiac injury, morphogenesis, angiogenesis, and tissue remodeling (eg, angiotensin I converting enzyme 2, STEAP family member 4, natriuretic peptide A, and secreted frizzled-related protein 4; all P<.05). Multiple gene sets and pathways that are involved in cardiac morphogenesis and vasculogenesis were downregulated significantly by gene set and Ingenuity Pathway Analysis (hallmark transforming growth factor beta signaling, cellular morphogenesis during differentiation, morphology of cardiovascular system; all P<.05).

CONCLUSION

Disruption of gene networks for cardiac morphogenesis and vasculogenesis occurred in the preterm fetal heart of nonhuman primates with preterm labor, intraamniotic infection, and severe fetal inflammation. Inflammatory injury to the fetal heart in utero may contribute to the development of heart disease later in life. Development of preterm labor therapeutics must also target fetal inflammation to lessen organ injury and potential long-term effects on cardiac function.

Impact of preterm birth on the developing myocardium of the neonate

BackgroundGlobally, ∼10% of infants are born before full term. Preterm birth exposes the heart to the demands of postnatal cardiovascular function before cardiac development is complete. Our aim was to examine, in hearts collected from infants at autopsy, the effects of preterm birth on myocardial structure and on cardiomyocyte development.Methods and resultsHeart tissue was collected at perinatal autopsies of 16 infants who died following preterm birth between 23 and 36 weeks of gestation, and survived for 1-42 days; the hearts of 37 appropriately grown stillborn infants, aged 20-40 weeks of gestation, were used for comparison. Using confocal microscopy and image analysis, cardiomyocyte proliferation, maturation, ploidy, and size were quantified, and interstitial collagen and myocardial capillarization were measured. Preterm birth resulted in a marked reduction in the proliferation of cardiomyocytes relative to age-matched stillborn infant controls (preterm vs. control P<0.0001). In contrast, preterm birth did not affect heart weight, capillarization, interstitial collagen or cardiomyocyte maturation, ploidy, and size.ConclusionsPreterm birth appears to lead to an abrupt reduction in cardiomyocyte cell division. This reduced cardiomyocyte proliferation in preterm infants may adversely impact upon the final number of cardiomyocytes which may reduce cardiac functional reserve, and impair the reparative capacity of the myocardium.

Physiological Stress Elicits Impaired Left Ventricular Function in Preterm-Born Adults

BACKGROUND

Experimental and clinical studies show that prematurity leads to altered left ventricular (LV) structure and function with preserved resting LV ejection fraction (EF). Large-scale epidemiological data now links prematurity to increased early heart failure risk.

OBJECTIVES

The authors performed echocardiographic imaging at prescribed exercise intensities to determine whether preterm-born adults have impaired LV functional response to physical exercise.

METHODS

We recruited 101 normotensive young adults born preterm (n = 47; mean gestational age 32.8 ± 3.2 weeks) and term (n = 54) for detailed cardiovascular phenotyping. Full clinical resting and exercise stress echocardiograms were performed, with apical 4-chamber views collected while exercising at 40%, 60%, and 80% of peak exercise capacity, determined by maximal cardiopulmonary exercise testing.

RESULTS

Preterm-born individuals had greater LV mass (p = 0.015) with lower peak systolic longitudinal strain (p = 0.038) and similar EF to term-born control subjects at rest (p = 0.62). However, by 60% exercise intensity, EF was 6.7% lower in preterm subjects (71.9 ± 8.7% vs 78.6 ± 5.4%; p = 0.004) and further declined to 7.3% below the term-born group at 80% exercise intensity (69.8 ± 6.4% vs 77.1 ± 6.3%; p = 0.004). Submaximal cardiac output reserve was 56% lower in preterm-born subjects versus term-born control subjects at 40% of peak exercise capacity (729 ± 1,162 ml/min/m2 vs. 1,669 ± 937 ml/min/m2; p = 0.021). LV length and resting peak systolic longitudinal strain predicted EF increase from rest to 60% exercise intensity in the preterm group (r = 0.68, p = 0.009 and r = 0.56, p = 0.031, respectively).

CONCLUSIONS

Preterm-born young adults had impaired LV response to physiological stress when subjected to physical exercise, which suggested a reduced myocardial functional reserve that might help explain their increased risk of early heart failure. (Young Adult Cardiovascular Health sTudy [YACHT]; NCT02103231).

Pediatric Cardiovascular Morbidity of the Early Term Newborn

OBJECTIVE

To determine whether early term delivery (at 37^0/7-38^6/7 weeks of gestation) is associated with long-term pediatric cardiovascular morbidity of the offspring.

STUDY DESIGN

A population-based cohort analysis was performed including all term deliveries occurring between 1991 and 2014 at a single tertiary medical center. Gestational age at delivery was subdivided into early term (37^0/7-38^6/7), full term (39^0/7-40^6/7), late term (41^0/7-41^6/7) and post term (≥42^0/7) delivery. Hospitalizations of children up to the age of 18 years involving cardiovascular morbidity were evaluated, including structural valvular disease, hypertension, arrhythmias, rheumatic fever, ischemic heart disease, pulmonary heart disease, perimyoendocarditis, congestive heart failure, and others. Kaplan-Meier survival curves were used to compare cumulative hospitalization incidence between groups. A multivariable Weibull parametric model was used to control for confounders.

RESULTS

During the study period, 223 242 term singleton deliveries met the inclusion criteria. Of them, 24% (n = 53 501) occurred at early term. Hospitalizations involving cardiovascular morbidity were significantly more common in children delivered at early term (0.7%) as compared with those born at full (0.6%), late (0.6%), or post term (0.5%; P = .01). The survival curve demonstrated a significantly higher cumulative incidence of cardiovascular-related hospitalizations in the early term group (log-rank P <.001). In the Weibull model, early term delivery was found to be an independent risk factor for cardiovascular-related hospitalization as compared with full term delivery (adjusted HR, 1.16; 95% CI, 1.01-1.32; P = .02).

CONCLUSION

Early term delivery is independently associated with pediatric cardiovascular morbidity of the offspring as compared with offspring born at full term.

Impaired autonomic function in adolescents born preterm

Preterm birth temporarily disrupts autonomic nervous system (ANS) development, and the long-term impacts of disrupted fetal development are unclear in children. Abnormal cardiac ANS function is associated with worse health outcomes, and has been identified as a risk factor for cardiovascular disease. We used heart rate variability (HRV) in the time domain (standard deviation of RR intervals, SDRR; and root means squared of successive differences, RMSSD) and frequency domain (high frequency, HF; and low frequency, LF) at rest, as well as heart rate recovery (HRR) following maximal exercise, to assess autonomic function in adolescent children born preterm. Adolescents born preterm (less than 36 weeks gestation at birth) in 2003 and 2004 and healthy age-matched full-term controls participated. Wilcoxon Rank Sum tests were used to compare variables between control and preterm groups. Twenty-one adolescents born preterm and 20 term-born controls enrolled in the study. Preterm-born subjects had lower time-domain HRV, including SDRR (69.1 ± 33.8 vs. 110.1 ± 33.0 msec, respectively, P = 0.008) and RMSSD (58.8 ± 38.2 vs. 101.5 ± 36.2 msec, respectively, P = 0.012), with higher LF variability in preterm subjects. HRR after maximal exercise was slower in preterm-born subjects at 1 min (30 ± 12 vs. 39 ± 9 bpm, respectively, P = 0.013) and 2 min (52 ± 10 vs. 60 ± 10 bpm, respectively, P = 0.016). This study is the first report of autonomic dysfunction in adolescents born premature. Given prior association of impaired HRV with adult cardiovascular disease, additional investigations into the mechanisms of autonomic dysfunction in this population are warranted.

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.

The economic impact of prematurity and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is one of the most serious chronic lung diseases in infancy and one of the most important sequels of premature birth (prevalence of 15-50%). Our objective was to estimate the cost of BPD of one preterm baby, with no other major prematurity-related complications, during the first 2 years of life in Spain. Data from the Spanish Ministry of Health regarding costs of diagnosis-related group of preterm birth, hospital admissions and visits, palivizumab administration, and oxygen therapy in the year 2013 were analyzed. In 2013, 2628 preterm babies were born with a weight under 1500 g; 50.9% were males. The need for respiratory support was 2.5% needed only oxygen therapy, 39.5% required conventional mechanical ventilation, and 14.9% required high-frequency ventilation. The incidence of BPD was of 34.9%. The cost of the first 2 years of life of a preterm baby with BPD and no other major prematurity-related complications ranged between 45,049.81 € and 118,760.43 €, in Spain, depending on birth weight and gestational age. If the baby required home oxygen therapy or developed pulmonary hypertension, this cost could add up to 181,742.43 €.

CONCLUSION

Prematurity and BPD have an elevated cost, even for public health care systems. This cost will probably increase in the coming years if the incidence and survival of preterm babies keeps rising. The development of new therapies and preventive strategies to decrease the incidence of BPD and other morbidities associated with prematurity should be a priority. What is known: • Bronchopulmonary dysplasia (BPD) is a serious chronic lung disease related with premature birth. • BPD is an increasing disease due to the up-rise in the number of premature births. What is new: • The economic cost of preterm birth and BPD has never before been estimated in Spain nor published with European data. • Preterm babies with BPD and a good clinical outcome carry also an important economic and social burden.

Pulmonary Artery Pressures in School-Age Children Born Prematurely

OBJECTIVES

To test the hypothesis that pulmonary artery pressures were higher in school aged children born extremely premature than those born at term. We also wanted to assess whether pulmonary artery pressures differed between children born prematurely with or without bronchopulmonary dysplasia (BPD) or between those randomized in the neonatal period to different ventilation modes.

STUDY DESIGN

Transthoracic echocardiography was performed on 193 children born extremely premature (106 had BPD) and 110 children born at term when they were 11-14 years of age. Ninety-nine children born extremely premature had been supported by high-frequency oscillation and 94 by conventional ventilation. Tricuspid regurgitation was assessed in the apical 4-chamber and modified parasternal long-axis views. Continuous-wave Doppler of the peak regurgitant jet velocity was used to estimate the right-ventricular-to-right-atrial systolic pressure gradient.

RESULTS

Tricuspid regurgitation was measurable in 71% (137/193) of the children born preterm and 75% (83/110) of the children born at term (P .23). The children born prematurely compared with the children born at term had a greater peak tricuspid regurgitation velocity (2.21 vs 1.95 m/s, P < .001) and the children born prematurely who had BPD vs those without BPD had a greater peak tricuspid regurgitation velocity (P = .023). There were no significant differences in pulmonary artery pressures according to neonatal ventilation mode.

CONCLUSIONS

Pulmonary artery pressures were estimated to be greater in 11- to 14-year-old children born extremely prematurely compared with those born at term and in those born prematurely who developed BPD compared with those who did not but did not differ significantly by neonatal ventilation mode.

Aortic stiffness and blood pressure variability in young people: a multimodality investigation of central and peripheral vasculature

Introduction:

Increased blood pressure (BP) variability is a cardiovascular risk marker for young individuals and may relate to the ability of their aorta to buffer cardiac output. We used a multimodality approach to determine relations between central and peripheral arterial stiffness and BP variability.

Methods:

We studied 152 adults (mean age of 31 years) who had BP variability measures based on SD of awake ambulatory BPs, 24-h weighted SD and average real variability (ARV). Global and regional aortic distensibility was measured by cardiovascular magnetic resonance, arterial stiffness by cardio-ankle vascular index (CAVI) and pulse wave velocity (PWV) by SphygmoCor (carotid–femoral) and Vicorder (brachial–femoral).

Results:

In young people, free from overt cardiovascular disease, all indices of SBP and DBP variability correlated with aortic distensibility (global aortic distensibility versus awake SBP SD: r = −0.39, P < 0.001; SBP ARV: r = −0.34, P < 0.001; weighted 24-h SBP SD: r = −0.42, P < 0.001). CAVI, which closely associated with aortic distensibility, also related to DBP variability, as well as awake SBP SD (r = 0.19, P < 0.05) and weighted 24-h SBP SD (r = 0.24, P < 0.01), with a trend for SBP ARV (r = 0.17, P = 0.06). In contrast, associations with PWV were only between carotid–femoral PWV and weighted SD of SBP (r = 0.20, P = 0.03) as well as weighted and ARV of DBP.

Conclusion:

Greater BP variability in young people relates to increases in central aortic stiffness, strategies to measure and protect aortic function from a young age may be important to reduce cardiovascular risk.

Adults born preterm: a review of general health and system-specific outcomes

In this review of 126 publications, we report that an overwhelming majority of adults born at preterm gestations remain healthy and well. However, a small, but a significant fraction of them remain at higher risk for neurological, personality and behavioural abnormalities, cardio-pulmonary functional limitations, systemic hypertension and metabolic syndrome compared to their term-born counterparts. The magnitude of increased risk differed across organ systems and varied across reports. The risks were proportional to the degree of prematurity at birth and seemed to occur more frequently among preterm infants born in the final two decades of the 20th century and later. These findings have considerable public health and clinical practice relevance.

CONCLUSION

Preterm birth needs to be considered a chronic condition, with a slight increase in the risk for long-term morbidities among adults born preterm. Therefore, obtaining a history of gestational age and weight at birth should be a routine part of care for patients of all age groups.

Preterm Birth and Risk of Heart Failure Up to Early Adulthood

BACKGROUND

In small clinical studies, preterm birth was associated with altered cardiac structure and increased cardiovascular mortality in the young.

OBJECTIVES

The goal of this study was to determine the association between preterm birth and risk of incident heart failure (HF) in children and young adults.

METHODS

This register-based cohort study included 2,665,542 individuals born in Sweden from 1987 to 2012 who were followed up from 1 year of age to December 31, 2013. The main study outcome was diagnosis of HF in the National Patient Register or the Cause of Death Register. The association between preterm birth and risk of incident HF was analyzed by using a Poisson regression model. Estimates were adjusted for maternal and pregnancy characteristics, socioeconomic status, and maternal and paternal cardiovascular disease.

RESULTS

During 34.8 million person-years of follow-up (median 13.1 years), there were 501 cases of HF. After exclusion of 52,512 individuals with malformations (n = 196 cases), 305 cases of HF remained (0.88 per 100,000 person-years). Gestational age was inversely associated with the risk of HF. Compared with individuals born at term (≥37 weeks' gestation), adjusted incidence relative risks for HF were 17.0 (95% confidence interval [CI]: 7.96 to 36.3) after extremely preterm birth (<28 weeks) and 3.58 (95% CI: 1.57 to 8.14) after very preterm birth (28 to 31 weeks). There was no risk increase after moderately preterm birth (32 to 36 weeks) (relative risk: 1.36; 95% CI: 0.87 to 2.13).

CONCLUSIONS

There was a strong association between preterm birth before 32 weeks of gestation and HF in childhood and young adulthood. Although the absolute risk of HF is low in young age, our findings indicate that preterm birth may be a previously unknown risk factor for HF.

Blood Pressure in 6-Year-Old Children Born Extremely Preterm

Background

Advances in perinatal medicine have increased infant survival after very preterm birth. Although this progress is welcome, there is increasing concern that preterm birth is an emerging risk factor for hypertension at young age, with implications for the lifetime risk of cardiovascular disease.

Methods and Results

We measured casual blood pressures (BPs) in a population‐based cohort of 6‐year‐old survivors of extremely preterm birth (<27 gestational weeks; n=171) and in age‐ and sex‐matched controls born at term (n=172). Measured BP did not differ, but sex, age‐, and height‐adjusted median z scores were 0.14 SD higher (P=0.02) for systolic BP and 0.10 SD higher (P=0.01) for diastolic BP in children born extremely preterm than in controls. Among children born extremely preterm, shorter gestation, higher body mass index, and higher heart rate at follow‐up were all independently associated with higher BP at 6 years of age, whereas preeclampsia, smoking in pregnancy, neonatal morbidity, and perinatal corticosteroid therapy were not. In multivariate regression analyses, systolic BP decreased by 0.10 SD (P=0.08) and diastolic BP by 0.09 SD (P=0.02) for each week‐longer gestation.

Conclusions

Six‐year‐old children born extremely preterm have normal but slightly higher BP than their peers born at term. Although this finding is reassuring for children born preterm and their families, follow‐up at older age is warranted.

Disproportionate cardiac hypertrophy during early postnatal development in infants born preterm

BackgroundAdults born very preterm have increased cardiac mass and reduced function. We investigated whether a hypertrophic phenomenon occurs in later preterm infants and when this occurs during early development.MethodsCardiac ultrasound was performed on 392 infants (33% preterm at mean gestation 34±2 weeks). Scans were performed during fetal development in 137, at birth and 3 months of postnatal age in 200, and during both fetal and postnatal development in 55. Cardiac morphology and function was quantified and computational models created to identify geometric changes.ResultsAt birth, preterm offspring had reduced cardiac mass and volume relative to body size with a more globular heart. By 3 months, ventricular shape had normalized but both left and right ventricular mass relative to body size were significantly higher than expected for postmenstrual age (left 57.8±41.9 vs. 27.3±29.4%, P<0.001; right 39.3±38.1 vs. 16.6±40.8, P=0.002). Greater changes were associated with lower gestational age at birth (left P<0.001; right P=0.001).ConclusionPreterm offspring, including those born in late gestation, have a disproportionate increase in ventricular mass from birth up to 3 months of postnatal age. These differences were not present before birth. Early postnatal development may provide a window for interventions relevant to long-term cardiovascular health.

Velocity vector imaging shows normal cardiac systolic function in survivors of severe bronchopulmonary dysplasia at six to 16 years of age

AIM

This study evaluated global myocardial function and associations between cardiac function and lung function in very low birth weight (VLBW) children, with and without severe radiographic bronchopulmonary dysplasia (BPD), at six to 14 years of age.

METHODS

We studied 34 VLBW and 19 term-born controls, and the VLBW group was further divided into a BPD group with severe radiographic BPD and those without radiographic BPD in infancy. Detailed right and left ventricular myocardial functions were analysed by velocity vector imaging, and the left ventricular mass was calculated. The associations between cardiac function and lung function were assessed by impulse oscillometry.

RESULTS

The right and left ventricular myocardial systolic functions and the left ventricular mass were similar in the three groups. Lung function was not associated with cardiac systolic function. Neonatal exposure to dexamethasone treatment was negatively associated with right ventricular function, as measured by the automated fractional area change, with an odds ratio of 7.9 and 95% confidence interval of 1.9-33.5 (p = 0.005).

CONCLUSION

Lung function measurements were not associated with cardiac systolic function in preterm infants at six to 14 years of age. Neonatal exposure to dexamethasone, used for weaning from the ventilator, was negatively associated with right ventricular function.

Pulmonary arterial resistance and compliance in preterm infants

BACKGROUND

Preterm birth is known to be associated with an increased risk of pulmonary arterial hypertension, although how preterm birth influences pulmonary hemodynamics has not been fully understood. Pulmonary arterial resistance (Rp) and compliance (Cp) are important factors to assess the pulmonary circulation. The purpose of this study is to clarify the relationship between Rp and Cp in preterm infants.

METHODS

We performed cardiac catheterization in 96 infants (50 males) with ventricular septal defect, and compared pulmonary hemodynamic parameters including Rp and Cp between preterm and full-term infants.

RESULTS

Thirteen infants were preterm. There were no significant differences in sex, age, preoperative pulmonary arterial pressure, preoperative pulmonary-to-systemic flow ratio, and preoperative Rp between the 2 groups. However, preoperative Cp and resistor-capacitor (RC) time in preterm infants were significantly lower than those in full-term infants (2.1 vs 2.8mL/mmHg/m² and 0.31 vs 0.36s, respectively; p<0.05 and p<0.01, respectively). Postoperative systolic and mean pulmonary arterial pressures were higher in preterm infants than those in full-term infants (29 vs 25mmHg and 18 vs 14mmHg, respectively; both p<0.01). It was also observed that postoperative Cp was lower in preterm infants, although postoperative Rp remained unchanged.

CONCLUSIONS

We demonstrated that preterm infants with pulmonary arterial hypertension had lower Cp than full-term infants, causing a modest increase in pulmonary arterial pressure. It is important to consider the unique pulmonary vasculature characterized by lower Cp, when managing preterm infants with congenital heart disease.

Adult Consequences of Extremely Preterm Birth: Cardiovascular and Metabolic Diseases Risk Factors, Mechanisms, and Prevention Avenues

Extremely preterm babies are exposed to various sources of injury during critical stages of development. The extremely preterm infant faces premature transition to ex utero physiology and undergoes adaptive mechanisms that may be deleterious in the long term because of permanent alterations in organ structure and function. Perinatal events can also directly cause structural injury. These disturbances induce morphologic and functional changes in their organ systems that might heighten their risks for later adult chronic diseases. This review examines the pathophysiology of programming of long-term health and diseases after preterm birth and associated perinatal risk factors.

Optimizing Nutrition in Preterm Low Birth Weight Infants-Consensus Summary

Preterm birth survivors are at a higher risk of growth and developmental disabilities compared to their term counterparts. Development of strategies to lower the complications of preterm birth forms the rising need of the hour. Appropriate nutrition is essential for the growth and development of preterm infants. Early administration of optimal nutrition to preterm birth survivors lowers the risk of adverse health outcomes and improves cognition in adulthood. A group of neonatologists, pediatricians, and nutrition experts convened to discuss and frame evidence-based recommendations for optimizing nutrition in preterm low birth weight (LBW) infants. The following were the primary recommendations of the panel: (1) enteral feeding is safe and may be preferred to parenteral nutrition due to the complications associated with the latter; however, parenteral nutrition may be a useful adjunct to enteral feeding in some critical cases; (2) early, fast, or continuous enteral feeding yields better outcomes compared to late, slow, or intermittent feeding, respectively; (3) routine use of nasogastric tubes is not advisable; (4) preterm infants can be fed while on ventilator or continuous positive airway pressure; (5) routine evaluation of gastric residuals and abdominal girth should be avoided; (6) expressed breast milk (EBM) is the first choice for feeding preterm infants due to its beneficial effects on cardiovascular, neurological, bone health, and growth outcomes; the second choice is donor pasteurized human milk; (7) EBM or donor milk may be fortified with human milk fortifiers, without increasing the osmolality of the milk, to meet the high protein requirements of preterm infants; (8) standard fortification is effective and safe but does not fulfill the high protein needs; (9) use of targeted and adjustable fortification, where possible, helps provide optimal nutrition; (10) optimizing weight gain in preterm infants prevents long-term cardiovascular complications; (11) checking for optimal weight and sucking/swallowing ability is essential prior to discharge of preterm infants; and (12) appropriate counseling and regular follow-up and monitoring after discharge will help achieve better long-term health outcomes. This consensus summary serves as a useful guide to clinicians in addressing the challenges and providing optimal nutrition to preterm LBW infants.