Association of Preterm Birth With Myocardial Fibrosis and Diastolic Dysfunction in Young Adulthood

Differences in Pulmonary Artery Stiffness Measured by CMR in Preterm-Born Young Adults With and Without Bronchopulmonary Dysplasia

BACKGROUND

Very preterm-born infants are at risk for developing bronchopulmonary dysplasia (BPD), a chronic lung disease. Nowadays, the majority of these infants reach adulthood. Very preterm-born young adults are at risk for developing pulmonary arterial (PA) hypertension later in life. An early sign of PA hypertension is increased PA stiffness. This study aims to use cardiovascular magnetic resonance to compare PA stiffness using PA relative area change (RAC) and pulse wave velocity (PWV) to identify early signs for PA hypertension in young adults born very premature, with and without BPD.

METHODS

Twenty preterm-born young adults with and 20 without BPD underwent cardiovascular magnetic resonance and were compared with 20 at-term-born young adults. RAC was calculated as the percentage change between the maximal and minimal areas of the PA. PWV was calculated using a method that simultaneously compares flow and area increase in the pulmonary artery during early systole.

RESULTS

In 57 of 60 patients, PWV and RAC measurements could be performed. Preterm-born young adults with BPD showed increased PWV compared with preterm-born young adults without BPD (median [25th-75th percentile] 2.07 m/s [1.45-3.05] versus 1.61 m/s [1.18-1.85]; P=0.04) and at-term-born young adults (1.35 m/s [1.08-2.23]; P=0.04). RAC was decreased in both preterm-born young adults with (62% [56-82]; P<0.01) and without BPD (78% [67-93]; P<0.01), compared with at-term-born young adults (101% [87-122]).

CONCLUSIONS

Preterm-born young adults with BPD show increased PA stiffness as measured by PWV compared with preterm-born young adults without BPD and at-term-born young adults; RAC was decreased in both preterm-born groups compared with at-term controls. This noninvasive method of measuring PA stiffness might be a valuable tool to identify individuals at risk for early signs of PA hypertension in this population.

Dose-related cardiac outcomes in response to postnatal dexamethasone treatment in premature lambs

BACKGROUND

Postnatal corticosteroids are used in the critical care of preterm infants for the prevention and treatment of bronchopulmonary dysplasia. We aimed to investigate the effects of early postnatal dexamethasone therapy and dose on cardiac maturation and morphology in preterm lambs.

METHODS

Lambs were delivered prematurely at ~128 days of gestational age and managed postnatally according to best clinical practice. Preterm lambs were administered dexamethasone daily at either a low-dose (n = 9) or a high-dose (n = 7), or were naïve to steroid treatment and administered saline (n = 9), over a 7-day time-course. Hearts were studied at postnatal Day 7 for gene expression and assessment of myocardial structure.

RESULTS

High-dose dexamethasone treatment in the early postnatal period led to marked differences in cardiac gene expression, altered cardiomyocyte maturation and reduced cardiomyocyte endowment in the right ventricle, as well as increased inflammatory infiltrates into the left ventricle. Low-dose exposure had minimal effects on the preterm heart.

CONCLUSION

Neonatal dexamethasone treatment led to adverse effects in the preterm heart in a dose-dependent manner within the first week of life. The observed cardiac changes associated with high-dose postnatal dexamethasone treatment may influence postnatal growth and remodeling of the preterm heart and subsequent long-term cardiac function.

Impact of Preterm Birth on Long-Term Cardiac Function: A Comprehensive Echocardiographic Study in School-Aged Children

Background and Objectives: This study aimed to evaluate the cardiac functions of 7- to 11-year-old children with a history of preterm birth using echocardiography and to assess the relationship between these functions and neonatal factors. Materials and Methods: A total of 64 children were included in the study, consisting of 32 children aged 7 to 11 years with a history of preterm birth and 32 age- and gender-matched term birth controls. Results: While no significant differences were detected between the preterm and term birth groups regarding age, height, and body weight, echocardiographic data revealed higher values of mitral E, mitral A, and tricuspid A by pulse wave Doppler, as well as septal E by tissue Doppler, in the preterm group compared to the term birth group (p < 0.05). Additionally, the left ventricular global longitudinal peak strain, right ventricular free wall and right ventricular 4-chamber strain, IVRT, MPI, MAPSE, and LVESV values were lower in the preterm group than in the term birth group (p < 0.05). No significant differences were detected in circumferential strain measurements. Right ventricular strain measurements were significantly lower in the preterm group (p = 0.001). Conclusions: While conventional echocardiographic examinations did not reveal obvious pathological findings in school-age children with a history of preterm birth, further echocardiographic assessments demonstrated differences compared to term birth controls, particularly in diastolic functions and right and left ventricular longitudinal strain measurements.

Small Left Ventricular Chamber Size and Mortality in a Large General Population

Enlargement of the left ventricle (LV) is an important marker of adverse cardiac remodeling and poor prognosis. Previous studies demonstrated increased cardiovascular risk in small subsets of patients with a small LV chamber size; however, the prognostic implications of small chamber size in the general population remains unclear. This study aimed to examine the prognosis of a small LV chamber in a large general cohort. All consecutive subjects who underwent echocardiography examinations from 2011 to 2023 were retrieved for analysis. Small chamber size was defined as end-diastolic diameter <42 mm for men and 37.8 mm for women as per American Society of Echocardiography guidelines. The primary end point for the study was all-cause mortality. A total of 46,529 subjects (mean age 60 ± 19 years, 56% men) were included, of whom 3,787 had a small LV chamber size. Clinical variables associated with small chamber included increasing age and lower body surface area. Echocardiographic variables included higher relative wall thickness and E/e' ratio. On the multivariable analysis, the presence of a small LV was significantly associated with mortality (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.22 to 1.46, p <0.001). This finding was significant in older (over 65 years) (HR 1.30, 95% CI 1.19 to 1.41, p <0.001) and younger (HR 2.09, 95% CI 1.81 to 2.41, p <0.001) subjects and in men and women. In conclusion, in this retrospective large cohort study, small LV chamber size was significantly associated with mortality in a broad range of patients. Further study is necessary to elucidate mechanisms and design preventive strategies.

Low birth weight associations with cardiac structure and function in adults after arterial switch for transposition of the great arteries

Background and aims

The objective of this study was to assess the associations of birth weight with cardiac structure and function in adults with dextro-transposition of the great arteries (D-TGA) who underwent the arterial switch operation (ASO).

Methods and results

Thirty-nine ASO patients (age 24.4 ± 3.3 years) were included during routine clinical follow-up from July 2019 to December 2021. All patients underwent cardiopulmonary exercise testing and cardiac magnetic resonance imaging at rest and during exercise. Early-life characteristics, including birth weight, were extracted from electronic medical health records. Linear regression analysis showed that lower birth weight was associated with smaller left ventricular (LV) and right ventricular (RV) end-diastolic volume index (LV: -14.5 mL/m2 [95 % confidence interval, CI: -26.5 to -2.5] per 1-kg decrease in birth weight, p = 0.04; RV: -11.2 mL/m2 [-20.7 to -1.7] per 1-kg decrease in birth weight, p = 0.03). Lower birth weight was associated with greater LV and RV ejection fraction at rest (LV: +8.5 % [+4.4 to +12.5] per 1-kg decrease in birth weight, p < 0.001); RV: +8.1 % [+2.8 to +13.4] per 1-kg decrease in birth weight, p = 0.005). Furthermore, lower birth weight was associated with an attenuated increase in LV stroke volume index from rest to peak exercise (-5.2 mL/m2 [-9.3 to -1.2] per 1-kg decrease in birth weight, p = 0.02).

Conclusions

Birth weight may be a novel risk factor for adverse cardiac remodeling in adult ASO patients. Further research is needed to delineate the mechanisms underlying the associations between birth weight and cardiac remodeling ASO patients as well as the broader adult CHD population.

Smaller Left Ventricular Size But Preserved Function in Adolescents and Adults Born Preterm

BACKGROUND

Prematurely born adults have increased risk for cardiovascular disease. There are limited cardiac data on US-born preterm individuals. We aimed to determine whether adolescents and adults born prematurely have altered left ventricular (LV) structure and function, and to interrogate diastolic function using isometric handgrip exercise.

METHODS AND RESULTS

Adolescents and adults born moderately to extremely preterm (≤32 weeks gestation or <1500 g birth weight) were recruited from the Parkland Health Neonatal Intensive Care Unit Registry. Full-term participants were recruited from the local area. Study procedures included anthropometrics and vitals, handgrip testing, and echocardiography performed at rest and during isometric handgrip exercise. Data were reported as mean±SD. The study enrolled 107 preterm and 48 term participants. Preterm participants (gestational age: 29.5±2.5 weeks) were shorter with higher body mass index (P<0.001) compared with term participants. Preterm participants exhibited smaller LV end-diastolic volume index (50.8±10.1 versus 56.9±10.0 mL/m2, P<0.001), LV stroke volume index (29.6±6.0 versus 34.1±6.5 mL/m2, P<0.001), and LV mass index (67.2±13.1 versus 73.3±14.2 g/m2, P=0.002) compared with term individuals. Preterm participants also had subclinical reductions in LV peak systolic tissue velocity and peak early diastolic tissue velocity lateral at rest. Isometric handgrip exercise promoted a reduction in diastolic function and an increase in hemodynamic measures, but changes during isometric handgrip exercise were similar between groups.

CONCLUSIONS

Adolescents and adults born preterm exhibit overall normal cardiac function despite smaller cardiac volumes and mass compared with individuals born full term. Effects are most pronounced at the lowest gestational ages.

Adverse childhood experiences: A health risk in emerging adulthood

Adverse Childhood Experiences (ACEs) represent a child's exposure to negative events that are detrimental to their mental and physical health. Despite this, very few studies have focused on the relationship between ACEs and physical health problems, in non-English-speaking populations and in emerging adulthood. Therefore, the objective of this study was to investigate the cumulative and differential impact of ACEs on diverse physical health problems in a Spanish population. Participants were 648 young adults (22% men), between the ages of 18 and 30 (mean age = 21.37, SD = 3.11), who completed the ACE Questionnaire and answered some questions about their health (e.g. asthma, obesity, global health). From the cumulative perspective, ACEs had a significant relationship with global health and asthma. Additionally, the differential approach revealed some specific ACEs related to three out of five health outcomes. Therefore, early detection of ACEs is of paramount importance to reduce their impact.

Respiratory, cardio-metabolic and neurodevelopmental long-term outcomes of moderate to late preterm birth: not just a near term-population. A follow-up study

INTRODUCTION

Moderate-to-late preterm infants constitute the majority within the preterm infant population. Most research on preterm infants has focused on very preterm children, often treating moderate-to-late preterm infants as similar to full-term infants. Our objective was to compare clinical, respiratory, cardio-metabolic and neurodevelopmental outcomes in adolescents aged 12-15 years born moderate and late preterm with a control group of the same age born full-term.

METHODS

Observational cross-sectional study, comparing moderate-to-late preterm (32-36+6 weeks' gestational age) with full-term adolescents (37-41+6 weeks' gestational age; 75 each group). Perinatal and neonatal history were collected as well as data on respiratory evolution (ISAAC questionnaire for asthma symptoms for adolescents 13-14 years), anthropometric values, learning difficulties, behavioral test (screening questionnaire for high-performance autism spectrum disorder and evaluation test for attention deficit hyperactivity disorder), skin prick test, pulmonary function test, echocardiogram and blood pressure. A blood test with metabolic profile was conducted.

RESULTS

Moderate-to-late preterm adolescents had more current asthma [p = 0.008, OR3 (95% CI 1.26-7.14)] and longer duration of combined treatments to control asthma (inhaled corticosteroids and anti-leukotrienes; p = 0.048). Forced vital capacity <80% was detected more often in moderate-to-late preterm patients (p = 0.013). When assessing right ventricle, moderate-to-late preterm adolescents showed better tricuspid annular plane systolic excursion z-score (p = 0.003), shortening fraction (p < 0.001) and E/A ratio z-score (p = 0.002). Regarding left ventricular assessment, moderate-to-late preterm group had smaller ventricle diastolic diameter (p = 0.04) and lower posterior wall z-score values (p = 0.037). They also showed a better S'wave z-score (p = 0.027), E wave (p = 0.005), E/A ratio (p = 0.003) and a higher septal myocardial performance index z-score (p = 0.025). Moderate-to-late preterm adolescents presented lower weight z-score (p = 0.039), body mass index z-score (p = 0.013), Waterlow weight index (p = 0.006) and higher undernutrition index [p = 0.04; OR 1.4 (95% CI 1-1.9)]. Although there were no differences in neurodevelopmental survey or behavioral tests.

CONCLUSION

Our findings underscore the importance of extended follow-up for this predominant group of premature infants to identify potential respiratory, cardiac and anthropometric issues that may emerge in the future.

Cardiovascular Sequelae of Bronchopulmonary Dysplasia in Preterm Neonates Born before 32 Weeks of Gestational Age: Impact of Associated Pulmonary and Systemic Hypertension

Bronchopulmonary dysplasia (BPD) remains the most common respiratory disorder of prematurity for infants born before 32 weeks of gestational age (GA). Early and prolonged exposure to chronic hypoxia and inflammation induces pulmonary hypertension (PH) with the characteristic features of a reduced number and increased muscularisation of the pulmonary arteries resulting in an increase in the pulmonary vascular resistance (PVR) and a fall in their compliance. BPD and BPD-associated pulmonary hypertension (BPD-PH) together with systemic hypertension (sHTN) are chronic cardiopulmonary disorders which result in an increased mortality and long-term problems for these infants. Previous studies have predominantly focused on the pulmonary circulation (right ventricle and its function) and developing management strategies accordingly for BPD-PH. However, recent work has drawn attention to the importance of the left-sided cardiac function and its impact on BPD in a subset of infants arising from a unique pathophysiology termed postcapillary PH. BPD infants may have a mechanistic link arising from chronic inflammation, cytokines, oxidative stress, catecholamines, and renin-angiotensin system activation along with systemic arterial stiffness, all of which contribute to the development of BPD-sHTN. The focus for the treatment of BPD-PH has been improvement of the right heart function through pulmonary vasodilators. BPD-sHTN and a subset of postcapillary PH may benefit from afterload reducing agents such as angiotensin converting enzyme inhibitors. Preterm infants with BPD-PH are at risk of later cardiac and respiratory morbidities as young adults. This paper reviews the current knowledge of the pathophysiology, diagnosis, and treatment of BPD-PH and BPD-sHTN. Current knowledge gaps and emerging new therapies will also be discussed.

Neonatal hyperoxia exposure leads to developmental programming of cardiovascular and renal disease in adult rats

Premature infants are often exposed to hyperoxia. However, there is limited data regarding the mechanistic underpinnings linking neonatal hyperoxia exposure and its contribution to cardio-renal dysfunction in adults born preterm. Our objective was to determine whether neonatal hyperoxia induces systemic vascular stiffness and cardio-renal dysfunction in adulthood. Newborn rats were randomly assigned to room air (RA) or hyperoxia (85% O2) from postnatal day 1 to 14, then recovered in RA until 1 year of life. Arterial stiffness, cardio-renal histomorphometry, and fibrosis in the aorta, heart, and kidney were assessed. RNA-sequencing (RNA-seq) of the aorta and kidney was also done. Adult rats exposed to neonatal hyperoxia had increased aortic and mesenteric artery stiffness as demonstrated by wire and pressure myography. They also had cardiomyocyte hypertrophy, glomerulomegaly, and tubular injury. Hyperoxia exposure altered the transcriptome profile associated with fibrosis and matrix remodeling in the aorta and kidney. There was also increased TGF-β1 levels and fibrosis in the aorta, left ventricle, and kidney. In conclusion, neonatal hyperoxia exposure was associated with systemic vascular and cardio-renal alterations in 1-year-old rats. Further studies to determine how targeted therapies could reprogram cardio-renal injury after neonatal hyperoxia exposure are indicated.

Cardiac dysfunction during exercise in young adults with bronchopulmonary dysplasia

Background

Worldwide, 1-2% of children are born premature and at risk for developing bronchopulmonary dysplasia (BPD). Preterm-born adults are at risk for early cardiovascular disease. The role of BPD is unclear. This study aims to examine cardiorespiratory function during submaximal exercise in young adult survivors of extreme prematurity, with or without BPD.

Methods

40 preterm-born young adults, 20 with BPD (median gestational age 27 weeks, interquartile range (IQR) 26-28 weeks) and 20 without BPD (median gestational age 28 weeks, IQR 27-29 weeks) were prospectively compared to age-matched at term-born adults (median gestational age 39 weeks, IQR 38-40 weeks). Participants underwent exercise testing and cardiovascular magnetic resonance with submaximal exercise.

Results

Resting heart rate in BPD subjects was higher than in at term-born subjects (69±10 mL versus 61±7 mL, p=0.01). Peak oxygen uptake during maximal cardiopulmonary exercise testing was decreased in BPD subjects (91±18% versus 106±17% of predicted, p=0.01). In BPD subjects, cardiac stroke volume change with exercise was impaired compared to at term-born subjects (11±13% versus 25±10%; p<0.001). With exercise, left ventricular end-diastolic volume decreased more in preterm-born subjects with versus without BPD (-10±8% versus -3±8%; p=0.01) and compared to at term-born subjects (0±5%; p<0.001). Exploratory data analysis revealed that exercise stroke volume and end-diastolic volume change were inversely correlated with oxygen dependency in those born prematurely.

Conclusions

In preterm-born young adults, particularly those with BPD, resting cardiac function, exercise performance and cardiac response to exercise is impaired compared to controls. Exercise cardiovascular magnetic resonance may reveal an important predisposition for heart disease later in life.

Bronchopulmonary dysplasia in adults: Exploring pathogenesis and phenotype

This review highlights both the longstanding impact of bronchopulmonary dysplasia (BPD) on the health of adult survivors of prematurity and the pressing need for prospective, longitudinal studies of this population. Conservatively, there are an estimated 1,000,000 survivors of BPD in the United States alone. Unfortunately, most of the available literature regarding outcomes of lung disease due to prematurity naturally focuses on pediatric patients in early or middle childhood, and the relative amount of literature on adult survivors is scant. As the number of adult survivors of BPD continues to increase, it is essential that both adult and pediatric pulmonologists have a comprehensive understanding of the pathophysiology and underlying disease process, including the molecular signaling pathways and pro-inflammatory modulators that contribute to the pathogenesis of BPD. We summarize the most common presenting symptoms for adults with BPD and identify the critical challenges adult pulmonologists face in managing the care of survivors of prematurity. Specifically, these challenges include the wide variability of the clinical presentation of adult patients, comorbid cardiopulmonary complications, and the paucity of longitudinal data available on these patients. Adult survivors of BPD have even required lung transplantation, indicating the high burden of morbidity that can result from premature birth and subsequent lung injury. In addition, we analyze the disparate symptoms and management approach to adults with "old" BPD versus "new" BPD. The aim of this review is to assist pulmonologists in understanding the underlying pathophysiology of BPD and to improve clinical recognition of this increasingly common pulmonary disease.

Pulmonary Hypertension in Established Bronchopulmonary Dysplasia: Physiologic Approaches to Clinical Care

Preterm infants with bronchopulmonary dysplasia (BPD) are prone to develop pulmonary hypertension (PH). Strong laboratory and clinical data suggest that antenatal factors, such as preeclampsia, chorioamnionitis, oligohydramnios, and placental dysfunction leading to fetal growth restriction, increase susceptibility for BPD-PH after premature birth. Echocardiogram metrics and serial assessments of NT-proBNP provide useful tools to diagnose and monitor clinical course during the management of BPD-PH, as well as monitoring for such complicating conditions as left ventricular diastolic dysfunction, shunt lesions, and pulmonary vein stenosis. Therapeutic strategies should include careful assessment and management of underlying airways and lung disease, cardiac performance, and systemic hemodynamics, prior to initiation of PH-targeted drug therapies.

Cardiac Remodeling After Hypertensive Pregnancy Following Physician-Optimized Blood Pressure Self-Management: The POP-HT Randomized Clinical Trial Imaging Substudy

BACKGROUND

Hypertensive pregnancy disorders are associated with adverse cardiac remodeling, which can fail to reverse in the postpartum period in some women. The Physician-Optimized Postpartum Hypertension Treatment trial demonstrated that improved blood pressure control while the cardiovascular system recovers postpartum associates with persistently reduced blood pressure. We now report the effect on cardiac remodeling.

METHODS

In this prospective, randomized, open-label, blinded end point trial, in a single UK hospital, 220 women were randomly assigned 1:1 to self-monitoring with research physician-optimized antihypertensive titration or usual postnatal care from a primary care physician and midwife. Participants were 18 years of age or older, with preeclampsia or gestational hypertension, requiring antihypertensives on hospital discharge postnatally. Prespecified secondary cardiac imaging outcomes were recorded by echocardiography around delivery, and again at blood pressure primary outcome assessment, around 9 months postpartum, when cardiovascular magnetic resonance was also performed.

RESULTS

A total of 187 women (101 intervention; 86 usual care) underwent echocardiography at baseline and follow-up, at a mean 258±14.6 days postpartum, of which 174 (93 intervention; 81 usual care) also had cardiovascular magnetic resonance at follow-up. Relative wall thickness by echocardiography was 0.06 (95% CI, 0.07-0.05; P<0.001) lower in the intervention group between baseline and follow-up, and cardiovascular magnetic resonance at follow-up demonstrated a lower left ventricular mass (-6.37 g/m2; 95% CI, -7.99 to -4.74; P<0.001), end-diastolic volume (-3.87 mL/m2; 95% CI, -6.77 to -0.98; P=0.009), and end-systolic volume (-3.25 mL/m2; 95% CI, 4.87 to -1.63; P<0.001) and higher left and right ventricular ejection fraction by 2.6% (95% CI, 1.3-3.9; P<0.001) and 2.8% (95% CI, 1.4-4.1; P<0.001), respectively. Echocardiography-assessed left ventricular diastolic function demonstrated a mean difference in average E/E' of 0.52 (95% CI, -0.97 to -0.07; P=0.024) and a reduction in left atrial volumes of -4.33 mL/m2 (95% CI, -5.52 to -3.21; P<0.001) between baseline and follow-up when adjusted for baseline differences in measures.

CONCLUSIONS

Short-term postnatal optimization of blood pressure control after hypertensive pregnancy, through self-monitoring and physician-guided antihypertensive titration, associates with long-term changes in cardiovascular structure and function, in a pattern associated with more favorable cardiovascular outcomes.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04273854.

Birth weight influences cardiac structure, function, and disease risk: evidence of a causal association

BACKGROUND AND AIMS

Low birth weight is a common pregnancy complication, which has been associated with higher risk of cardiometabolic disease in later life. Prior Mendelian randomization (MR) studies exploring this question do not distinguish the mechanistic contributions of variants that directly influence birth weight through the foetal genome (direct foetal effects), vs. variants influencing birth weight indirectly by causing an adverse intrauterine environment (indirect maternal effects). In this study, MR was used to assess whether birth weight, independent of intrauterine influences, is associated with cardiovascular disease risk and measures of adverse cardiac structure and function.

METHODS

Uncorrelated (r2 < .001), genome-wide significant (P < 5 × 10-8) single nucleotide polymorphisms were extracted from genome-wide association studies summary statistics for birth weight overall, and after isolating direct foetal effects only. Inverse-variance weighted MR was utilized for analyses on outcomes of atrial fibrillation, coronary artery disease, heart failure, ischaemic stroke, and 16 measures of cardiac structure and function. Multiple comparisons were accounted for by Benjamini-Hochberg correction.

RESULTS

Lower genetically-predicted birth weight, isolating direct foetal effects only, was associated with an increased risk of coronary artery disease (odds ratio 1.21, 95% confidence interval 1.06-1.37; P = .031), smaller chamber volumes, and lower stroke volume, but higher contractility.

CONCLUSIONS

The results of this study support a causal role of low birth weight in cardiovascular disease, even after accounting for the influence of the intrauterine environment. This suggests that individuals with a low birth weight may benefit from early targeted cardiovascular disease prevention strategies, independent of whether this was linked to an adverse intrauterine environment during gestation.

Association of Gestational Age at Birth With Left Cardiac Dimensions at Near-Term Corrected Age Among Extremely Preterm Infants

BACKGROUND

Remodeling and altered ventricular geometry have been described in adults born preterm. Although they seem to have an adverse cardiac phenotype, the impact of various degrees of prematurity on cardiac development has been scarcely reported. In this study, we evaluated the impact of gestational age (GA) at birth on cardiac dimensions and function at near-term age among extremely preterm infants.

METHODS

This is a retrospective single-center cohort study of infants born at <29 weeks of GA between 2015 and 2019. Infants with available clinically acquired echocardiography between 34 and 43 weeks were included. Two groups were investigated: those born <26 weeks and those born ≥26 weeks. All measurements were done by an expert masked to clinical data using the raw images. The primary outcome was measurements of cardiac dimensions and function based on GA group. Secondary outcomes were the association between cardiac dimensions and postnatal steroid exposure and with increments of GA at birth.

RESULTS

A total of 205 infants were included (<26 weeks, n = 102; ≥26 weeks, n = 103). At time of echocardiography, weight (2.4 ± 0.5 vs 2.5 ± 0.5 kg, P = .86) and age (37.2 ± 1.6 vs 37.1 ± 1.9 weeks, P = .74) were similar between groups. There was no difference in metrics of right-sided dimensions and function. However, left-sided dimensions were decreased in infants born <26 weeks, including systolic left ventricle (LV) diameter (1.06 ± 0.20 cm vs 1.12 ± 0.18 cm, P = .02), diastolic LV length (2.85 ± 0.37 vs 3.02 ± 0.57 cm, P = .02), and estimated LV end-diastolic volume (5.36 ± 1.69 vs 6.01 ± 1.79 mL, P = .02).

CONCLUSIONS

In our cohort of very immature infants, birth at the extreme of prematurity was associated with smaller left cardiac dimensions around 36 weeks of corrected age. Future longitudinal prospective studies should evaluate further the impact of prematurity on LV development and performance and their long-term clinical impact.

Preterm pigs for preterm birth research: reasonably feasible

Preterm birth will disrupt the pattern and course of organ development, which may result in morbidity and mortality of newborn infants. Large animal models are crucial resources for developing novel, credible, and effective treatments for preterm infants. This review summarizes the classification, definition, and prevalence of preterm birth, and analyzes the relationship between the predicted animal days and one human year in the most widely used animal models (mice, rats, rabbits, sheep, and pigs) for preterm birth studies. After that, the physiological characteristics of preterm pig models at different gestational ages are described in more detail, including birth weight, body temperature, brain development, cardiovascular system development, respiratory, digestive, and immune system development, kidney development, and blood constituents. Studies on postnatal development and adaptation of preterm pig models of different gestational ages will help to determine the physiological basis for survival and development of very preterm, middle preterm, and late preterm newborns, and will also aid in the study and accurate optimization of feeding conditions, diet- or drug-related interventions for preterm neonates. Finally, this review summarizes several accepted pediatric applications of preterm pig models in nutritional fortification, necrotizing enterocolitis, neonatal encephalopathy and hypothermia intervention, mechanical ventilation, and oxygen therapy for preterm infants.

Birth Weight Is Associated With Clonal Hematopoiesis of Indeterminate Potential and Cardiovascular Outcomes in Adulthood

Background High and low birth weight are independently associated with increased cardiovascular disease risk in adulthood. Clonal hematopoiesis of indeterminate potential (CHIP), the age-related clonal expansion of hematopoietic cells with preleukemic somatic mutations, predicts incident cardiovascular disease independent of traditional cardiovascular risk factors. Whether birth weight predicts development of CHIP later in life is unknown. Methods and Results A total of 221 047 adults enrolled in the UK Biobank with whole exome sequences and self-reported birth weight were analyzed. Of those, 22 030 (11.5%) had low (<2.5 kg) and 29 292 (14.7%) high birth weight (>4.0 kg). CHIP prevalence was higher among participants with low (6.0%, P=0.049) and high (6.3%, P<0.001) versus normal birth weight (5.7%, ref.). Multivariable-adjusted logistic regression analyses demonstrated that each 1-kg increase in birth weight was associated with a 3% increased risk of CHIP (odds ratio, 1.03 [95% CI, 1.00-1.06]; P=0.04), driven by a stronger association observed between birth weight and DNMT3A CHIP (odds ratio, 1.04 per 1-kg increase [95% CI, 1.01-1.08]; P=0.02). Mendelian randomization analyses supported a causal relationship of longer gestational age at delivery with DNMT3A CHIP. Multivariable Cox regression demonstrated that CHIP was independently and additively associated with incident cardiovascular disease or death across birth weight groups, with highest absolute risks in those with CHIP plus high or low birth weight. Conclusions Higher birth weight is associated with increased risk of developing CHIP in midlife, especially DNMT3A CHIP. These findings identify a novel risk factor for CHIP and provide insights into the relationships among early-life environment, CHIP, cancer, and cardiovascular disease.

Myocardial function including estimates of myocardial work in young adults born very preterm or with extremely low birthweight - a cohort study

BACKGROUND

Preterm birth and low birthweight have been associated with increased risk of heart failure and cardiovascular disease in young adulthood. However, results from clinical studies of myocardial function are not consistent. Echocardiographic strain analyses allow detection of early stages of cardiac dysfunction, and non-invasive estimates of myocardial work can provide additional information on cardiac function. We aimed to evaluate left ventricular (LV) myocardial function including measures of myocardial work in young adults born very preterm (gestational age < 29 weeks) or with extremely low birthweight (< 1000 g) (PB/ELBW), compared with term-born age- and sex matched controls.

METHODS

63 PB/ELBW and 64 controls born in Norway in the periods 1982-1985, 1991-1992, and 1999-2000 were examined with echocardiography. LV ejection fraction (EF) and LV global longitudinal strain (GLS) were measured. Myocardial work was estimated from LV pressure-strain loops after determination of GLS and construction of a LV pressure curve. Diastolic function was evaluated by determination of the presence or absence of elevated LV filling pressure, including measures of left atrial longitudinal strain.

RESULTS

The PB/ELBW with mean birthweight 945 (standard deviation (SD) 217) grams, mean gestational age 27 (SD 2) weeks, and mean age 27 (SD 6) years had LV systolic function mainly within normal range. Only 6% had EF < 50% or impaired GLS >-16%, but 22% had borderline impaired GLS between - 16% and - 18%. Mean GLS in PB/ELBW (-19.4% (95% confidence interval (CI) -20.0, -18.9)) was impaired compared to controls (-20.6% (95% CI -21.1, -20.1)), p = 0.003. Lower birthweight was associated to more impaired GLS (Pearson correlation coefficient - 0.2). Means of EF, measures of diastolic function including left atrial reservoir strain, global constructive and wasted work, global work index and global work efficiency was similar in PB/ELBW and controls.

CONCLUSION

The young adults born very preterm or with extremely low birthweight had impaired LV-GLS compared to controls, although systolic function mainly within normal range. Lower birthweight was associated with more impaired LV-GLS. These findings could indicate an elevated lifetime risk of developing heart failure in preterm born individuals. Measures of diastolic function and myocardial work were similar compared to controls.

Lower birth weight is linked to poorer cardiovascular health in middle-aged population-based adults

OBJECTIVE

To examine associations of birth weight with clinical and imaging indicators of cardiovascular health and evaluate mechanistic pathways in the UK Biobank.

METHODS

Competing risk regression was used to estimate associations of birth weight with incident myocardial infarction (MI) and mortality (all-cause, cardiovascular disease, ischaemic heart disease, MI), over 7-12 years of longitudinal follow-up, adjusting for age, sex, deprivation, maternal smoking/hypertension and maternal/paternal diabetes. Mediation analysis was used to evaluate the role of childhood growth, adulthood obesity, cardiometabolic diseases and blood biomarkers in mediating the birth weight-MI relationship. Linear regression was used to estimate associations of birth weight with left ventricular (LV) mass-to-volume ratio, LV stroke volume, global longitudinal strain, LV global function index and left atrial ejection fraction.

RESULTS

258 787 participants from white ethnicities (61% women, median age 56 (49, 62) years) were studied. Birth weight had a non-linear relationship with incident MI, with a significant inverse association below an optimal threshold of 3.2 kg (subdistribution HR: 1.15 (1.08 to 1.22), p=6.0×10-5) and attenuation to the null above this threshold. The birth weight-MI effect was mediated through hypertension (8.4%), glycated haemoglobin (7.0%), C reactive protein (6.4%), high-density lipoprotein (5.2%) and high cholesterol (4.1%). Birth weight-mortality associations were statistically non-significant after Bonferroni correction. In participants with cardiovascular magnetic resonance (n=19 314), lower birth weight was associated with adverse LV remodelling (greater concentricity, poorer function).

CONCLUSIONS

Lower birth weight was associated with greater risk of incident MI and unhealthy LV phenotypes; effects were partially mediated through cardiometabolic disease and systemic inflammation. These findings support consideration of birth weight in risk prediction and highlight actionable areas for disease prevention.

Characteristics of Myocardial Blood Vessels in Preterm Rats in the Late Postnatal Ontogeny

Immunohistochemical study (CD31 detection) and morphometric analysis (evaluation of specific volumes of cardiomyocytes and blood capillaries, diameter of blood capillaries, trophic index, and pericapillary diffusion zone) of the left ventricular myocardium in preterm (12 h and 24 h preterm) Wistar rats was carried out on postnatal days 56 and 180. A decrease in the trophic index and an increase in the zone of pericapillary diffusion in the myocardium of the left ventricle in preterm rats were shown, which indicates deterioration of the heart supply during the postnatal ontogeny.

Heart rate surge at respiratory event termination in preterm and term born children with sleep disordered breathing

BACKGROUND

Repetitive surges in heart rate (HR) at respiratory event termination underpin the altered autonomic HR control associated with sleep disordered breathing (SDB). As children born preterm are at greater risk of adverse cardiovascular outcomes, we aimed to determine whether the HR response to obstructive respiratory events was elevated compared to term-born children.

METHODS

Fifty children (3-12 years) born preterm, were matched for SDB severity, age and gender with term born children. Multilevel modelling determined the effect of preterm birth and arousal on HR changes between a 10s baseline to the latter half of respiratory events and 15s post event during NREM and REM.

RESULTS

1203 events were analysed (NREM: term 380; preterm 383; REM: term 207; preterm 233). During NREM fewer events terminated in arousal in the preterm compared with term group (preterm 68%; term 84%; χ² = 27.2, p < 0.001). There were no differences in REM. During NREM, HR was lower in the preterm group at all event phases, with and without associated arousals (P < 0.01 for all). % change in HR from baseline to post event was higher in the preterm compared with term group (preterm: median 23% IQR (12%,34%); term: 18% (10%,29%); p < 0.01) and late event to post event (preterm: 30% (21%, 32%); term 28% (20%,39%); p < 0.01) in events associated with arousals.

CONCLUSION

The greater magnitude of surges in HR following respiratory events terminating with arousal in preterm born children, although small, occur repeatedly throughout the night and may contribute to adverse cardiovascular outcomes, although further studies are required.

Differing Impact of Preterm Birth on the Right and Left Atria in Adulthood

Background Preterm birth affects 10% of live births and is associated with an altered left ventricular and right ventricular phenotype and increased cardiovascular disease risk in young adulthood. Because left atrial (LA) and right atrial (RA) volume and function are known independent predictors of cardiovascular outcomes, we investigated whether these were altered in preterm-born young adults. Methods and Results Preterm-born (n=200) and term-born (n=266) adults aged 18 to 39 years underwent cardiovascular magnetic resonance imaging. LA and RA maximal and minimal volumes (absolute, indexed to body surface area, and as a ratio to ventricular volumes) were obtained to study atrial morphology, while LA and RA stroke volume, strain, and strain rate were used to assess atrial function. Secondary analyses consisted of between-group comparisons based on degree of prematurity. Absolute RA volumes and RA volumes indexed to right ventricular volumes were significantly smaller in preterm-born compared with term-born adults. In addition, RA reservoir and booster strain were higher in preterm-born adults, possibly indicating functional compensation for the smaller RA volumes. LA volumes indexed to left ventricular volumes were significantly greater in preterm-born adults as compared with term-born adults, although absolute LA volumes were similar between groups. LA and RA changes were observed across gestational ages in the preterm group but were greatest in those born very-to-extremely preterm. Conclusions Preterm-born adults show changes in LA and RA structure and function, which may indicate subclinical cardiovascular disease. Further research into underlying mechanisms, opportunities for interventions, and their prognostic value is warranted.

Preterm Birth Is Associated With Adverse Cardiac Remodeling and Worse Outcomes in Patients With a Functional Single Right Ventricle

OBJECTIVE

To assess the effects of preterm birth on cardiac structure and function and transplant-free survival in patients with hypoplastic left heart syndrome and associated anomalies throughout the staged palliation process.

STUDY DESIGN

Data from the Single Ventricle Reconstruction trial were used to assess the impact of prematurity on echocardiographic measures at birth, Norwood, Stage II, and 14 months in 549 patients with a single functional right ventricle. Medical history was recorded once a year using medical records or telephone interviews. Cox regression models were applied to analyze transplant-free survival to age 6 years. Causal mediation analysis was performed to estimate the mediating effect of birth weight within this relationship.

RESULTS

Of the 549 participants, 64 (11.7%) were born preterm. Preterm-born participants had lower indexed right ventricle end-diastolic volumes at birth but higher volumes than term-born participants by age 14 months. Preterm-born participants had an increased risk of death or heart transplantation from birth to age 6 years, with an almost linear increase in the observed risk as gestational age decreased below 37 weeks. Of the total effect of preterm birth on transplant-free survival, 27.3% (95% CI 2.5-59.0%) was mediated through birth weight.

CONCLUSIONS

Preterm birth is associated with adverse right ventricle remodeling and worse transplant-free survival throughout the palliation process, in part independently of low birth weight. Further investigation into this vulnerable group may allow development of strategies that mitigate the impact of prematurity on outcomes in patients with hypoplastic left heart syndrome.

Exercise and hypoxia unmask pulmonary vascular disease and right ventricular dysfunction in a 10- to 12-week-old swine model of neonatal oxidative injury

Prematurely born young adults who experienced neonatal oxidative injury (NOI) of the lungs have increased incidence of cardiovascular disease. Here, we investigated the long-term effects of NOI on cardiopulmonary function in piglets at the age of 10-12 weeks. To induce NOI, term-born piglets (1.81 ± 0.06 kg) were exposed to hypoxia (10-12%F iO 2 ${F}_{{\rm{iO}}_{\rm{2}}}$ ), within 2 days after birth, and maintained for 4 weeks or until symptoms of heart failure developed (range 16-28 days), while SHAM piglets were normoxia raised. Following recovery (>5 weeks), NOI piglets were surgically instrumented to measure haemodynamics during hypoxic challenge testing (HCT) and exercise with modulation of the nitric-oxide system. During exercise, NOI piglets showed a normal increase in cardiac index, but an exaggerated increase in pulmonary artery pressure and a blunted increase in left atrial pressure - suggesting left atrial under-filling - consistent with an elevated pulmonary vascular resistance (PVR), which correlated with the duration of hypoxia exposure. Moreover, hypoxia duration correlated inversely with stroke volume (SV) during exercise. Nitric oxide synthase inhibition and HCT resulted in an exaggerated increase in PVR, while the PVR reduction by phosphodiesterase-5 inhibition was enhanced in NOI compared to SHAM piglets. Finally, within the NOI piglet group, prolonged duration of hypoxia was associated with a better maintenance of SV during HCT, likely due to the increase in RV mass. In conclusion, duration of neonatal hypoxia appears an important determinant of alterations in cardiopulmonary function that persist further into life. These changes encompass both pulmonary vascular and cardiac responses to hypoxia and exercise. KEY POINTS: Children who suffered from neonatal oxidative injury, such as very preterm born infants, have increased risk of cardiopulmonary disease later in life. Risk stratification requires knowledge of the mechanistic underpinning and the time course of progression into cardiopulmonary disease. Exercise and hypoxic challenge testing showed that 10- to 12-week-old swine that previously experienced neonatal oxidative injury had increased pulmonary vascular resistance and nitric oxide dependency. Duration of neonatal oxidative injury was a determinant of structural and functional cardiopulmonary remodelling later in life. Remodelling of the right ventricle, as a result of prolonged neonatal oxidative injury, resulted in worse performance during exercise, but enabled better performance during the hypoxic challenge test. Increased nitric oxide dependency together with age- or comorbidity-related endothelial dysfunction may contribute to predisposition to pulmonary hypertension later in life.

Reshaping the Preterm Heart: Shifting Cardiac Renin-Angiotensin System Towards Cardioprotection in Rats Exposed to Neonatal High-Oxygen Stress

BACKGROUND

Approximately 10% of infants are born preterm. Preterm birth leads to short and long-term changes in cardiac shape and function. By using a rat model of neonatal high-oxygen (80%O₂) exposure, mimicking the premature hyperoxic transition to the extrauterine environment, we revealed a major role of the renin-angiotensin system peptide Angio II (angiotensin II) and its receptor AT1 (angiotensin receptor type 1) on neonatal O₂-induced cardiomyopathy. Here, we tested whether treatment with either orally active compounds of the peptides Angio-(1-7) or alamandine included in cyclodextrin could prevent postnatal cardiac remodeling and the programming of cardiomyopathy induced by neonatal high-O₂ exposure.

METHODS

Sprague-Dawley pups were exposed to room air or 80% O₂ from postnatal day 3 (P3) to P10. Neonatal rats were treated orally from P3 to P10 and assessed at P10 and P28. Left ventricular (LV) shapes were characterized by tridimensional computational atlases of ultrasound images in addition to histomorphometry.

RESULTS

At P10, high O₂-exposed rats presented a smaller, globular and hypertrophied LV shape versus controls. Treatment with cyclodextrin-Angio-(1-7) significantly improved LV function in the O₂-exposed neonatal rats and slightly changed LV shape. Cyclodextrin-alamandine and cyclodextrin-Angio-(1-7) treatments similarly reduced hypertrophy at P10 as well as LV remodeling and dysfunction at P28. Both treatments upregulated cardiac angiotensin-converting enzyme 2 in O₂-exposed rats at P10 and P28.

CONCLUSIONS

Our findings demonstrate LV remodeling changes induced by O₂-stress and the potential benefits of treatments targeting the cardioprotective renin-angiotensin system axis, supporting the neonatal period as an important window for interventions aiming at preventing cardiomyopathy in people born preterm.

Diffuse Myocardial Fibrosis at Cardiac MRI in Young Adults Born Prematurely: A Cross-sectional Cohort Study

Purpose

To measure native T1 values, a marker of diffuse fibrosis, by using cardiac MRI (CMR) in young adults born prematurely.

Materials and Methods

This secondary analysis of a prospective cohort study included young adults born moderately to extremely preterm and age-matched, term-born participants. CMR was performed with a 3.0-T imager that included cine imaging for the quantification of left ventricular (LV) and right ventricular (RV) volumes and function and native saturation recovery T1 mapping for the assessment of diffuse myocardial fibrosis. Values between preterm and term were compared by using the Student t test. Associations between T1 values and other variables were analyzed by using linear regression and multivariate regression.

Results

Of the 50 young-adult participants, 32 were born preterm (mean age, 25.8 years ± 4.2 [SD]; 23 women) and 18 were born at term (mean age, 26.2 years ± 5.4; 10 women). Native T1 values were significantly higher in participants born preterm than in participants born at term (1477 msec ± 77 vs 1423 msec ± 71, respectively; unadjusted P = .0019). Native T1 values appeared to be positively associated with indexed LV end-diastolic and end-systolic volumes (β = 2.1, standard error = 0.7 and β = 3.8, standard error = 1.2, respectively), the RV end-diastolic volume index (β = 1.3, standard error = 0.6), and the LV mass index (β = 2.5, standard error = 0.9). Higher T1 values may be associated with reduced cardiac systolic strain measures and diastolic strain measures. Five-minute Apgar scores were inversely associated with native T1 values.

Conclusion

Young adults born moderately to extremely preterm exhibited significantly higher native T1 values than age-matched, term-born young adults.

Keywords: MRI, Cardiac, Heart, Left Ventricle, Cardiomyopathies

Clinical trial registration no. NCT03245723

Published under a CC BY 4.0 license

Supplemental material is available for this article.

New Insights Into Cerebrovascular Pathophysiology and Hypertension

Despite advances in acute management and prevention of cerebrovascular disease, stroke and vascular cognitive impairment together remain the world's leading cause of death and neurological disability. Hypertension and its consequences are associated with over 50% of ischemic and 70% of hemorrhagic strokes but despite good control of blood pressure (BP), there remains a 10% risk of recurrent cerebrovascular events, and there is no proven strategy to prevent vascular cognitive impairment. Hypertension evolves over the lifespan, from predominant sympathetically driven hypertension with elevated mean BP in early and mid-life to a late-life phenotype of increasing systolic and falling diastolic pressures, associated with increased arterial stiffness and aortic pulsatility. This pattern may partially explain both the increasing incidence of stroke in younger adults as well as late-onset, chronic cerebrovascular injury associated with concurrent systolic hypertension and historic mid-life diastolic hypertension. With increasing arterial stiffness and autonomic dysfunction, BP variability increases, independently predicting the risk of ischemic and intracerebral hemorrhage, and is potentially modifiable beyond control of mean BP. However, the interaction between hypertension and control of cerebral blood flow remains poorly understood. Cerebral small vessel disease is associated with increased pulsatility in large cerebral vessels and reduced reactivity to carbon dioxide, both of which are being targeted in early phase clinical trials. Cerebral arterial pulsatility is mainly dependent upon increased transmission of aortic pulsatility via stiff vessels to the brain, while cerebrovascular reactivity reflects endothelial dysfunction. In contrast, although cerebral autoregulation is critical to adapt cerebral tone to BP fluctuations to maintain cerebral blood flow, its role as a modifiable risk factor for cerebrovascular disease is uncertain. New insights into hypertension-associated cerebrovascular pathophysiology may provide key targets to prevent chronic cerebrovascular disease, acute events, and vascular cognitive impairment.

Acute and chronic cardiac adaptations in adults born preterm

New Findings

What is the topic of this review?

Studies using cardiovascular magnetic resonance imaging and echocardiography to investigate cardiac alterations at rest and during exercise‐induced physiological stress in adults born preterm.

What advances does it highlight?

People born preterm have a greater long‐term cardiovascular risk, which may be explained in part by their cardiac structural and functional alterations. They have potentially adverse alterations in left and right ventricular structure and function that worsens with blood pressure elevation; an impaired myocardial functional reserve; and an increase in diffuse myocardial fibrosis that may drive their lower diastolic function.

Abstract

Preterm birth accounts for more than 10% of births worldwide and associates with a long‐term increase in cardiovascular disease risk. The period around preterm birth is a rapid and critical phase of cardiovascular development, which might explain why changes in multiple components of the cardiovascular system have been observed in individuals born preterm. These alterations include reduced microvascular density, increased macrovascular stiffness, and higher systolic and diastolic blood pressure. Cardiac alterations have been observed in people born preterm as early as neonatal life and infancy, with potentially adverse changes in both left and right ventricular structure and function extending into adulthood. Indeed, studies using cardiovascular magnetic resonance imaging and echocardiography have demonstrated that preterm‐born individuals have structural cardiac changes and functional impairments. Furthermore, myocardial tissue characterization by cardiovascular magnetic resonance imaging has demonstrated an increase in left ventricular diffuse myocardial fibrosis in young adults born preterm, and under acute physiological stress, their myocardial functional reserve assessed by echocardiography is reduced. The preterm heart is also more susceptible to chronic systolic blood pressure elevation, with a significantly greater increase in left ventricular mass as systolic blood pressure rises observed in preterm‐born compared to term‐born young adults. Given these known, potentially adverse acute and chronic cardiac adaptations in the preterm‐born population, primary prevention strategies are needed to reduce long‐term cardiovascular disease risk in this subgroup of the population.

Understanding the Preterm Human Heart: What do We Know So Far?

Globally, preterm birth affects more than one in every 10 live births. Although the short‐term cardiopulmonary complications of prematurity are well known, long‐term health effects are only now becoming apparent. Indeed, preterm birth has been associated with elevated cardiovascular morbidity and mortality in adulthood. Experimental animal models and observational human studies point toward changes in heart morphology and function from birth to adulthood in people born preterm that may contribute to known long‐term risks. Moreover, recent data support the notion of a heterogeneous cardiac phenotype of prematurity, which is likely driven by various maternal, early, and late life factors. This review aims to describe the early fetal‐to‐neonatal transition in preterm birth, the different structural and functional changes of the preterm human heart across developmental stages, as well as potential factors contributing to the cardiac phenotype of prematurity.

Perinatal Origins of Adult Disease and Opportunities for Health Promotion: A Narrative Review

The "developmental origins of health and disease" (DOHaD) hypothesis refers to the influence of early developmental exposures and fetal growth on the risk of chronic diseases in later periods. During fetal and early postnatal life, cell differentiation and tissue formation are influenced by several factors. The interaction between genes and environment in prenatal and early postnatal periods appears to be critical for the onset of multiple diseases in adulthood. Important factors influencing this interaction include genetic predisposition, regulation of gene expression, and changes in microbiota. Premature birth and intrauterine growth restriction (IUGR) are other important factors considered by the DOHaD hypothesis. Preterm birth is associated with impaired or arrested structural or functional development of key organs/systems, making preterm infants vulnerable to cardiovascular, respiratory, and chronic renal diseases during adulthood. Growth restriction, defined as impaired fetal growth compared to expected biological potential in utero, is an additional negative factor increasing the risk of subsequent diseases. Environmental factors implicated in the developmental programming of diseases include exposure to pollution, stress, drugs, toxic agents, nutrition, and exercise. The DOHaD may explain numerous conditions, including cardiovascular, metabolic, respiratory, neuropsychiatric, and renal diseases. Potential antenatal and postnatal preventive measures, interventions, and future directions are discussed.

From Other Journals: A Review of Recent Articles by Our Editorial Team

In this review, we provide a brief description of recently published articles addressing topics relevant to pediatric cardiologists. Our hope is to provide a summary of the latest articles published recently in other journals in our field. The articles address (1) preterm birth association with ventricular fibrosis and diastolic dysfunction in adulthood, (2) shared decision-making as a viable strategy to counsel patients with long QT syndrome to return to play, (3) using pulmonary-to-aortic surgical shunt in patients with severe pulmonary hypertension which is associated with similar 5-year survival compared to lung transplant, (4) the use of donor-derived cell-free DNA to screen for heart transplant rejection, and (5) the role of microvasculature in hypoplastic left heart syndrome using cardiac magnetic resonance.

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.

The heart in congenital diaphragmatic hernia: Knowns, unknowns, and future priorities

There is growing recognition that the heart is a key contributor to the pathophysiology of congenital diaphragmatic hernia (CDH), in conjunction with developmental abnormalities of the lung and pulmonary vasculature. Investigations to date have demonstrated altered fetal cardiac morphology, notably relative hypoplasia of the fetal left heart, as well as early postnatal right and left ventricular dysfunction which appears to be independently associated with adverse outcomes. However, many more unknowns remain, not least an understanding of the genetic and cellular basis for cardiac dysplasia and dysfunction in CDH, the relationship between fetal, postnatal and long-term cardiac function, and the impact on other parts of the body especially the developing brain. Consensus on how to measure and classify cardiac function and pulmonary hypertension in CDH is also required, potentially using both non-invasive imaging and biomarkers. This may allow routine assessment of the relative contribution of cardiac dysfunction to individual patient pathophysiological phenotype and enable better, individualized therapeutic strategies incorporating targeted use of fetal therapies, cardiac pharmacotherapies, and extra-corporeal membrane oxygenation (ECMO). Collaborative, multi-model approaches are now required to explore these unknowns and fully appreciate the role of the heart in CDH.

Cardiac Left Ventricle Mitochondrial Dysfunction After Neonatal Exposure to Hyperoxia: Relevance for Cardiomyopathy After Preterm Birth

Supplemental Digital Content is available in the text.

Individuals born preterm present left ventricle changes and increased risk of cardiac diseases and heart failure. The pathophysiology of heart disease after preterm birth is incompletely understood. Mitochondria dysfunction is a hallmark of cardiomyopathy resulting in heart failure. We hypothesized that neonatal hyperoxia in rats, a recognized model simulating preterm birth conditions and resulting in oxygen-induced cardiomyopathy, induce left ventricle mitochondrial changes in juvenile rats. We also hypothesized that humanin, a mitochondrial-derived peptide, would be reduced in young adults born preterm.