Right ventricular systolic dysfunction in young adults born preterm

Association of Systolic Blood Pressure Elevation With Disproportionate Left Ventricular Remodeling in Very Preterm-Born Young Adults: The Preterm Heart and Elevated Blood Pressure

Question

Are left ventricular structure and function in preterm-born adults more susceptible to remodeling in association with blood pressure elevation?

Findings

In this cross-sectional cohort study of 468 adults with cardiac magnetic resonance imaging, left ventricular mass index and mass to end-diastolic volume ratio were greater for each 1–mm Hg elevation in systolic blood pressure in preterm-born adults than in term-born adults, with the greatest rise in those born very and extremely preterm (<32 weeks’ gestation).

Meaning

The findings of this study show that adults born preterm demonstrate greater remodeling in response to systolic blood pressure elevation and may require earlier interventions to prevent cardiovascular disease progression.

Importance

Preterm-born individuals have higher blood pressure with an increased risk of hypertension by young adulthood, as well as potentially adverse cardiac remodeling even when normotensive. To what extent blood pressure elevation affects left ventricular (LV) structure and function in adults born preterm is currently unknown.

Objective

To investigate whether changes observed in LV structure and function in preterm-born adults make them more susceptible to cardiac remodeling in association with blood pressure elevation.

Design, Setting, and Participants

This cross-sectional cohort study, conducted at the Oxford Cardiovascular Clinical Research Facility and Oxford Centre for Clinical Magnetic Resonance Research, included 468 adults aged 18 to 40 years. Of these, 200 were born preterm (<37 weeks’ gestation) and 268 were born at term (≥37 weeks’ gestation). Cardiac magnetic resonance imaging was used to characterize LV structure and function, with clinical blood pressure readings measured to assess hypertension status. Demographic and anthropometric data, as well as birth history and family medical history information, were collected. Data were analyzed between January 2012 and February 2021.

Main Outcomes and Measures

Cardiac magnetic resonance measures of LV structure and function in response to systolic blood pressure elevation.

Results

The cohort was primarily White (>95%) with a balanced sex distribution (51.5% women and 48.5% men). Preterm-born adults with and without hypertension had higher LV mass index, reduced LV function, and smaller LV volumes compared with term-born individuals both with and without hypertension. In regression analyses of systolic blood pressure with LV mass index and LV mass to end-diastolic volume ratio, there was a leftward shift in the slopes in preterm-born compared with term-born adults. Compared with term-born adults, there was a 2.5-fold greater LV mass index per 1–mm Hg elevation in systolic blood pressure in very and extremely preterm-born adults (<32 weeks’ gestation) (0.394 g/m² vs 0.157 g/m² per 1 mm Hg; P < .001) and a 1.6-fold greater LV mass index per 1–mm Hg elevation in systolic blood pressure in moderately preterm-born adults (32 to 36 weeks’ gestation) (0.250 g/m² vs 0.157 g/m² per 1 mm Hg; P < .001). The LV mass to end-diastolic volume ratio per 1–mm Hg elevation in systolic blood pressure in the very and extremely preterm-born adults was 3.4-fold greater compared with those born moderately preterm (3.56 × 10⁻³ vs 1.04 × 10⁻³ g/mL per 1 mm Hg; P < .001) and 3.3-fold greater compared with those born at term (3.56 × 10⁻³ vs 1.08 × 10⁻³ g/mL per 1 mm Hg; P < .001).

Conclusions and Relevance

Preterm-born adults have a unique LV structure and function that worsens with systolic blood pressure elevation. Additional primary prevention strategies specifically targeting cardiovascular risk reduction in this population may be warranted.

Increased circulating endothelial progenitor cells (EPCs) in prepubertal children born prematurely: a possible link between prematurity and cardiovascular risk

BACKGROUND

Endothelial progenitor cells (EPCs) ensure vascular integrity and neovascularization. No studies have investigated EPCs in preterm-born children beyond infancy.

METHODS

One hundred and thirty-six prepubertal children were enrolled: 63 preterm and 73 born at term (controls). Circulating CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs were measured in preterm-born children compared to controls. Body mass index (BMI), waist-to-hip ratio (WHR), neck circumference, systolic and diastolic blood pressure (SBP and DBP, respectively), fasting glucose, insulin, lipid profile, common carotid and abdominal aortic intima-media thickness (cIMT and aIMT, respectively), endothelium-dependent brachial artery flow-mediated dilation (FMD), and echocardiographic parameters were also assessed.

RESULTS

Circulating CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs were significantly higher in preterm-born children compared to controls (p < 0.001 and p < 0.001, respectively). In total study population and in the preterm-born group, EPCs were significantly lower in children born to mothers with gestational diabetes compared to non-diabetic mothers. Prematurity was associated with higher WHR, neck circumference, SBP, DBP, cIMT, aIMT, mean pressure, and velocity of pulmonary artery; the peak velocity of the brachial artery was significantly lower in children born prematurely. In multiple regression analysis, preterm birth and maternal gestational diabetes were recognized as independent predictors of EPCs.

CONCLUSIONS

Circulating EPCs were increased in prepubertal preterm-born children in comparison with peers born full-term. Maternal gestational diabetes was associated with a decrease in EPCs.

IMPACT

Mounting evidence supports the adverse effect of prematurity on cardiovascular health. However, the underlying mechanisms that could lead to endothelial dysfunction in preterm-born individuals are not fully understood. Endothelial progenitor cells (EPCs) ensure vascular integrity, normal endothelial function and neovascularization. No studies have investigated the EPCs counts in peripheral blood beyond infancy in children born prematurely. Circulating EPCs were significantly higher in preterm-born prepubertal children compared to controls, thus indicating that prematurity is possibly associated with endothelial damage. In total study population and in the preterm-born group, maternal gestational diabetes was associated with decreased EPCs concentrations.

Association of Preterm Birth With Long-term Risk of Heart Failure Into Adulthood

IMPORTANCE

Preterm birth has been associated with increased risk of heart failure (HF) early in life, but its association with new-onset HF in adulthood appears to be unknown.

OBJECTIVE

To determine whether preterm birth is associated with increased risk of HF from childhood into mid-adulthood in a large population-based cohort.

DESIGN, SETTING, AND PARTICIPANTS

This national cohort study was conducted in Sweden with data from 1973 through 2015. All singleton live births in Sweden during 1973 through 2014 were included.

EXPOSURES

Gestational age at birth, identified from nationwide birth records.

MAIN OUTCOMES AND MEASURES

Heart failure, as identified from inpatient and outpatient diagnoses through 2015. Cox regression was used to determine hazard ratios (HRs) for HF associated with gestational age at birth while adjusting for other perinatal and maternal factors. Cosibling analyses assessed for potential confounding by unmeasured shared familial (genetic and/or environmental) factors.

RESULTS

A total of 4 193 069 individuals were included (maximum age, 43 years; median age, 22.5 years). In 85.0 million person-years of follow-up, 4158 persons (0.1%) were identified as having HF (median [interquartile range] age, 15.4 [28.0] years at diagnosis). Preterm birth (gestational age <37 weeks) was associated with increased risk of HF at ages younger than 1 year (adjusted HR [aHR], 4.49 [95% CI, 3.86-5.22]), 1 to 17 years (aHR, 3.42 [95% CI, 2.75-4.27]), and 18 to 43 years (aHR, 1.42 [95% CI, 1.19-1.71]) compared with full-term birth (gestational age, 39-41 weeks). At ages 18 through 43 years, the HRs further stratified by gestational age were 4.72 (95% CI, 2.11-10.52) for extremely preterm births (22-27 weeks), 1.93 (95% CI, 1.37-2.71) for moderately preterm births (28-33 weeks), 1.24 (95% CI, 1.00-1.54) for late preterm births (34-36 weeks), and 1.09 (95% CI, 0.97-1.24) for early term births (37-38 weeks). The corresponding HF incidence rates (per 100 000 person-years) at ages 18 through 43 years were 31.7, 13.8, 8.7, and 7.3, respectively, compared with 6.6 for full-term births. These associations persisted when excluding persons with structural congenital cardiac anomalies. The associations at ages 18 through 43 years (but not <18 years) appeared to be largely explained by shared determinants of preterm birth and HF within families. Preterm birth accounted for a similar number of HF cases among male and female individuals.

CONCLUSIONS AND RELEVANCE

In this large national cohort, preterm birth was associated with increased risk of new-onset HF into adulthood. Survivors of preterm birth may need long-term clinical follow-up into adulthood for risk reduction and monitoring for HF.

Postnatal Expression Profile of MicroRNAs Associated with Cardiovascular Diseases in 3- to 11-Year-Old Preterm-Born Children

(1) Background: Preterm-born children have an increased cardiovascular risk with the first clinical manifestation during childhood and/or adolescence. (2) Methods: The occurrence of overweight/obesity, prehypertension/hypertension, valve problems or heart defects, and postnatal microRNA expression profiles were examined in preterm-born children at the age of 3 to 11 years descending from preterm prelabor rupture of membranes (PPROM) and spontaneous preterm birth (PTB) pregnancies. The whole peripheral blood gene expression of 29 selected microRNAs associated with cardiovascular diseases was the subject of our interest. (3) Results: Nearly one-third of preterm-born children (32.43%) had valve problems and/or heart defects. The occurrence of systolic and diastolic prehypertension/hypertension was also inconsiderable in a group of preterm-born children (27.03% and 18.92%). The vast majority of children descending from either PPROM (85.45%) or PTB pregnancies (85.71%) had also significantly altered microRNA expression profiles at 90.0% specificity. (4) Conclusions: Postnatal microRNA expression profiles were significantly influenced by antenatal and early postnatal factors (gestational age at delivery, birth weight of newborns, and condition of newborns at the moment of birth). These findings may contribute to the explanation of increased cardiovascular risk in preterm-born children. These findings strongly support the belief that preterm-born children should be dispensarized for a long time to have access to specialized medical care.

Altered Right Ventricular Filling at Four-dimensional Flow MRI in Young Adults Born Prematurely

Purpose

To use four-dimensional (4D) flow MRI to measure intraventricular flow in young adults who were born prematurely to investigate mechanisms that may account for increased heart failure risk in this population.

Materials and Methods

In this secondary analysis of a prospective study, a total of 56 young adults participated in an observational cardiac 4D flow MRI study from 2016 to 2020. There were 35 participants who had been born moderately to extremely prematurely (birth weight <1500 g or gestational age ≤32 weeks; 23 women; mean age, 26 years ± 4) and 21 term-born participants (11 women; mean age, 25 years ± 3). Participants underwent cardiac MRI, including cine cardiac structure and function assessment, as well as 4D flow MRI. In each ventricle, normalized kinetic energy (KE/end diastolic volume) and flow through the atrioventricular valve were computed and compared between term-born and preterm participants at systolic and diastolic (early diastolic filling rate [E wave] and late diastolic filling [atrial contraction] rate [A wave]) time points by using Wilcoxon rank-sum tests.

Results

Preterm-born participants had lower right ventricular (RV) E wave/A wave (E/A) KE ratios (2.4 ± 1.7 vs 3.5 ± 1.4; P <.01) and lower E/A peak filling rate ratios (computed from RV volume-time curves; 2.3 ± 1.3 vs 3.5 ± 2.5; P = .03). Additionally, viscous energy dissipation was increased during systole (5.7 µW/mL ± 3.0 vs 4.2 µW/mL ± 1.6; P = .03), increased during late diastole (3.9 µW/mL ± 4.0 vs 2.2 µW/mL ± 1.6; P = .03), and summed over the cardiac cycle (2.4 µJ/mL ± 1.0 vs 1.9 µJ/mL ± 0.6; P = .02) in preterm relative to term participants.

Conclusion

These results suggest that RV diastolic filling is altered in young adults who were born moderately to severely prematurely.Supplemental material is available for this article. Keywords: Adults, Cardiac, Comparative Studies, MR-Imaging, Right Ventricle © RSNA, 2021.

Sildenafil administration improves right ventricular function on 4D flow MRI in young adults born premature

Extreme preterm birth conveys an elevated risk of heart failure by young adulthood. Smaller biventricular chamber size, diastolic dysfunction, and pulmonary hypertension may contribute to reduced ventricular-vascular coupling. However, how hemodynamic manipulations may affect right ventricular (RV) function and coupling remains unknown. As a pilot study, 4D flow MRI was used to assess the effect of afterload reduction and heart rate reduction on cardiac hemodynamics and function. Young adults born premature were administered sildenafil (a pulmonary vasodilator) and metoprolol (a β blocker) on separate days, and MRI with 4D flow completed before and after each drug administration. Endpoints include cardiac index (CI), direct flow fractions, and ventricular kinetic energy including E/A wave kinetic energy ratio. Sildenafil resulted in a median CI increase of 0.24 L/min/m2 (P = 0.02), mediated through both an increase in heart rate (HR) and stroke volume. Although RV ejection fraction improved only modestly, there was a significant increase (4% of end diastolic volume) in RV direct flow fraction (P = 0.04), consistent with hemodynamic improvement. Metoprolol administration resulted in a 5-beats/min median decrease in HR (P = 0.01), a 0.37 L/min/m2 median decrease in CI (P = 0.04), and a reduction in time-averaged kinetic energy (KE) in both ventricles (P < 0.01), despite increased RV diastolic E/A KE ratio (P = 0.04). Despite reduced right atrial workload, metoprolol significantly depressed overall cardiac systolic function. Sildenafil, however, increased CI and improved RV function, as quantified by the direct flow fraction. The preterm heart appears dependent on HR but sensitive to RV afterload manipulations.NEW & NOTEWORTHY We assessed the effect of right ventricular afterload reduction with sildenafil and heart rate reduction with metoprolol on cardiac hemodynamics and function in young adults born premature using 4D flow MRI. Metoprolol depressed cardiac function, whereas sildenafil improved cardiac function including right ventricular direct flow fraction by 4D flow, consistent with hemodynamic improvement. This suggests that the preterm heart is dependent on heart rate and sensitive to right ventricular afterload changes.

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

Background

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

Methods

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

Results

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

Conclusion

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

Left Ventricle Phenotyping Utilizing Tissue Doppler Imaging in Premature Infants with Varying Severity of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is characterized by alveolar-capillary simplification and is associated with pulmonary hypertension (PH) in preterm infants. The contribution of left ventricle (LV) disease towards this severe BPD-PH phenotype is not well established. We aimed to describe the longitudinal trajectory of the LV function as measured by tissue Doppler imaging (TDI) and its association with BPD-PH. We retrospectively assessed prospectively acquired clinical and echocardiographic data from 77 preterm infants born between 2011 and 2013. We characterized the LV function by measuring systolic and diastolic myocardial velocities (s’, e’, a’), isovolumetric relaxation time (IVRT), and myocardial performance index with TDI at three time periods from 32 and 36 weeks, postmenstrual age through one year of age. We also measured post systolic motion (PSM), a marker of myocardial dysfunction that results from asynchronous movement of the ventricular walls, and not previously described in preterm infants. Patients were stratified into groups according to BPD severity and the presence of PH and compared over time. Conventional TDI measures of the LV function were similar between groups, but the septal PSM was significantly prolonged over the first year of age in patients with BPD-PH. PSM provides a novel objective way to assess the hemodynamic impact of lung and pulmonary vascular disease severity on LV function in preterm infants with BPD and PH.

Preterm birth and cardiac function in adulthood

Preterm birth affects 1 in 10 pregnancies worldwide, with increasing survival rates over the last 30 years. However, as this new generation of long-term survivors approaches middle age, recent studies have revealed increased cardiovascular risk factors and higher rates of ischaemic heart disease and heart failure. Cardiovascular imaging has identified smaller cardiac chamber size, changes in myocardial mass and impaired ventricular function, particularly under physiological stress. Accordingly, this population should be recognised as having a higher risk of heart failure as they age. In this review, we present current evidence for increased rates of heart failure and evidence of alterations in cardiac structure and function in those born preterm. We discuss potential mechanisms to explain this risk including greater frequency of co-morbidities known to be associated with heart failure. We also explore potential mechanistic links specific to the preterm-born population, including the impact of premature birth on myocardial and vascular development and the effects of perinatal haemodynamic changes and chronic lung disease on the developing heart. We highlight gaps in our knowledge and consider implications for patient management relevant to the adult physician.

Very preterm birth results in later lower platelet activation markers

BACKGROUND

Premature birth entails an adverse cardiovascular risk profile, but the underlying mechanisms are insufficiently understood. Here, we employed an unbiased cardiovascular proteomics approach to profile former very preterm-born preschoolers.

METHODS

This observational study investigated differences in plasma concentrations of 79 proteins, including putative cardiovascular biomarkers between very preterm- and term-born children on average 5.5 years old (53.1% male) using multiple-reaction monitoring mass spectrometry.

RESULTS

Very preterm-born (n = 38; median gestational age 29.6 weeks) compared to term-born (n = 26; 40.2 weeks) children featured lower plasma concentrations of platelet factor 4 (PLF4; -61.6%, P < 0.0001), platelet basic protein (CXCL7; -57.8%, P < 0.0001), and hemoglobin subunit beta (-48.3%, P < 0.0001). Results remained virtually unchanged when adjusting for complete blood count parameters, including platelet count. Conversely, whole blood hemoglobin was higher (+7.62%, P < 0.0001) in preterm-born children.

CONCLUSIONS

Very preterm birth was associated with decreased markers of platelet activation among preschoolers. These findings are consistent with reduced platelet reactivity persisting from very preterm birth to a preschool age.

IMPACT

Former very preterm-born preschoolers featured reduced levels of platelet activation markers. While lower platelet reactivity in very preterm-born compared to term-born infants in the first days of life was established, it was unknown when, if at all, reactivity normalizes. The current study suggests that platelet hyporeactivity due to very preterm birth persists at least up to a preschool age. "Immaturity of the hemostatic system" may be a persistent sequel of preterm birth, but larger studies are needed to investigate its potential clinical implications.

Dynamic FDG PET Imaging to Probe for Cardiac Metabolic Remodeling in Adults Born Premature

Individuals born very premature have an increased cardiometabolic and heart failure risk. While the structural differences of the preterm heart are now well-described, metabolic insights into the physiologic mechanisms underpinning this risk are needed. Here, we used dynamic fluorodeoxyglucose (FDG) positron emission tomography/magnetic resonance imaging (PET-MRI) in young adults born term and preterm during normoxic (N = 28 preterm; 18 term) and hypoxic exposure (12% O2; N = 26 preterm; 17 term) to measure the myocardial metabolic rate of glucose (MMRglc) in young adults born term (N = 18) and preterm (N = 32), hypothesizing that young adults born preterm would have higher rates of MMRglc under normoxic conditions and a reduced ability to augment glucose metabolism under hypoxic conditions. MMRglc was calculated from the myocardial and blood pool time-activity curves by fitting the measured activities to the 3-compartment model of FDG kinetics. MMRglc was similar at rest between term and preterm subjects, and decreased during hypoxia exposure in both groups (p = 0.02 for MMRglc hypoxia effect). There were no differences observed between groups in the metabolic response to hypoxia, either globally (serum glucose and lactate measures) or within the myocardium. Thus, we did not find evidence of altered myocardial metabolism in the otherwise healthy preterm-born adult. However, whether subtle changes in myocardial metabolism may preceed or predict heart failure in this population remains to be determined.

The Preterm Heart-Brain Axis in Young Adulthood: The Impact of Birth History and Modifiable Risk Factors

People born preterm are at risk of developing both cardiac and brain abnormalities. We aimed to investigate whether cardiovascular physiology may directly affect brain structure in young adulthood and whether cardiac changes are associated with modifiable biomarkers. Forty-eight people born preterm, followed since birth, underwent cardiac MRI at age 25.1 ± 1.4 years and brain MRI at age 33.4 ± 1.0 years. Term born controls were recruited at both time points for comparison. Cardiac left and right ventricular stroke volume, left and right ventricular end diastolic volume and right ventricular ejection fraction were significantly different between preterm and term born controls and associated with subcortical brain volumes and fractional anisotropy in the corpus callosum in the preterm group. This suggests that cardiovascular abnormalities in young adults born preterm are associated with potentially adverse future brain health. Associations between left ventricular stroke volume indexed to body surface area and right putamen volumes, as well as left ventricular end diastolic length and left thalamus volumes, remained significant when adjusting for early life factors related to prematurity. Although no significant associations were found between modifiable biomarkers and cardiac physiology, this highlights that cardiovascular health interventions may also be important for brain health in preterm born adults.

Cardiac and vascular health in late preterm infants

Adults who were born preterm are at increased risk of hypertension and cardiovascular disease in later life. Infants born late preterm are the majority of preterm births; however, the effect of late preterm on risk of cardiovascular disease is unclear. The objective of this study was to assess whether vascular health and cardiac autonomic control differ in a group of late preterm newborn infants compared to a group of term-born infants.A total of 35 healthy late preterm newborn infants, with normal growth (34-36 completed weeks' gestation) and 139 term-born infants (37-42 weeks' gestation) were compared in this study. Aortic wall thickening, assessed as aortic intima-media thickness (IMT) by high-resolution ultrasound, and cardiac autonomic control, assessed by heart rate variability, were measured during the first week of life. Postnatal age of full-term and late preterm infants at the time of the study was 5 days (standard deviation [SD] 5) and 4 days (SD 3), respectively.Infants born late preterm show reduced aortic IMT (574 μm [SD 51] vs. 612 μm [SD 73]) and reduced heart rate variability [log total power 622.3 (606.5) ms2 vs. 1180. 6 (1114.3) ms2], compared to term infants. These associations remained even after adjustment for sex and birth weight.Infants born late preterm show selective differences in markers of cardiovascular risk, with potentially beneficial differences in aortic wall thickness in contrast to potentially detrimental differences in autonomic control, when compared with term-born control infants. These findings provide pathophysiologic evidence to support an increased risk of hypertension and sudden cardiac death in individuals born late preterm.

Exaggerated Cardiac Contractile Response to Hypoxia in Adults Born Preterm

Individuals born prematurely have smaller hearts, cardiac limitations to exercise, and increased overall cardiometabolic risk. The cardiac effects of acute hypoxia exposure as another physiologic stressor remain under explored. The purpose of this study was to determine the effects of hypoxia on ventricular function in adults born preterm. Adults born moderately to extremely preterm (≤32 weeks gestation or <1500 g, N = 32) and born at term (N = 18) underwent cardiac magnetic resonance imaging under normoxic (21% O₂) and hypoxic (12% O₂) conditions to assess cardiovascular function. In normoxia, cardiac function parameters were similar between groups. During hypoxia, the right ventricular (RV) contractile response was significantly greater in participants born premature, demonstrated by greater increases in RV ejection fraction (EF) (p = 0.002), ventricular-vascular coupling (VVC) (p = 0.004), and strain (p < 0.0001) measures compared to term-born participants, respectively. Left ventricular contractile reserve was similar to term-born participants. Adults born preterm exhibit an exaggerated contractile response to acute hypoxia, particularly in the RV. This suggests that adults born preterm may have contractile reserve, despite the lack of volume reserve identified in previous exercise studies. However, this exaggerated and hyper-adapted response may also increase their risk for late RV failure.

Association of Bronchopulmonary Dysplasia and Right Ventricular Systolic Function in Young Adults Born Preterm

BACKGROUND

Adults born preterm are at a higher risk of cardiopulmonary disease and premature death. Preterm birth is associated with abnormalities in right ventricular (RV) structure and function, but the impact of bronchopulmonary dysplasia (BPD), a common complication of extremely preterm birth, on these parameters remains unknown.

RESEARCH QUESTION

Are preterm birth and BPD associated with alterations in RV structure and function in early adulthood?

STUDY DESIGN AND METHODS

Echocardiographic and spirometry data were obtained from the Health of Adults Born Preterm Investigation (HAPI). RV structure and performance were evaluated by using echocardiography, and respiratory function was assessed by using spirometry.

RESULTS

The study comprised 86 young adults born preterm before 30 weeks of gestation, including 28 with moderate to severe BPD, and 85 adults of the same age born full term. Individuals were assessed at a mean age of 23 years. RV systolic function was altered in the preterm group, with lower tricuspid annular plane systolic excursion and lower RV s' and RV outflow tract velocity time integral values, especially in those born preterm with BPD. Nine (36%) participants born preterm with BPD, six (13%) participants born preterm without BPD, and six (8%) participants born full term had a tricuspid annular plane systolic excursion value < 16 mm, a marker of RV systolic dysfunction (P value for the comparison between preterm no BPD and BPD, .032). No difference was found in RV diastolic function or estimates of pulmonary artery pressure between groups. Although respiratory function was altered in those born preterm, and more so in the case of BPD, no association was observed between spirometry indices of respiratory function and RV systolic function.

INTERPRETATION

Preterm birth is associated in adulthood with alterations in RV systolic function, which are more pronounced in the case of BPD.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03261609; URL: www.clinicaltrials.gov.

Predicting the outcomes of preterm neonates beyond the neonatal intensive care unit: What are we missing?

Preterm infants are a population at high risk for mortality and adverse health outcomes. With recent improvements in survival to childhood, increasing attention is being paid to risk of long-term morbidity, specifically during childhood and young-adulthood. Although numerous tools for predicting the functional outcomes of preterm neonates have been developed in the past three decades, no studies have provided a comprehensive overview of these tools, along with their strengths and weaknesses. The purpose of this article is to provide an in-depth, narrative review of the current risk models available for predicting the functional outcomes of preterm neonates. A total of 32 studies describing 43 separate models were considered. We found that most studies used similar physiologic variables and standard regression techniques to develop models that primarily predict the risk of poor neurodevelopmental outcomes. With a recently expanded knowledge regarding the many factors that affect neurodevelopment and other important outcomes, as well as a better understanding of the limitations of traditional analytic methods, we argue that there is great room for improvement in creating risk prediction tools for preterm neonates. We also consider the ethical implications of utilizing these tools for clinical decision-making. IMPACT: Based on a literature review of risk prediction models for preterm neonates predicting functional outcomes, future models should aim for more consistent outcomes definitions, standardized assessment schedules and measurement tools, and consideration of risk beyond physiologic antecedents. Our review provides a comprehensive analysis and critique of risk prediction models developed for preterm neonates, specifically predicting functional outcomes instead of mortality, to reveal areas of improvement for future studies aiming to develop risk prediction tools for this population. To our knowledge, this is the first literature review and narrative analysis of risk prediction models for preterm neonates regarding their functional outcomes.

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

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

The determinants of positivisation of anterior T-wave inversion in children

BACKGROUND

Anterior T-wave inversion (aTWI) can be a common electrical sign in cardiomyopathies but also a benign feature regressing with age in healthy children. Unfortunately, little is known about the age of positivisation of aTWI and its determinants in children and longitudinal data are not available. The aim of this longitudinal study was to identify the age and determinants of positivisation of aTWI in healthy children.

METHODS

ATWI was observed in 331 healthy children. They were evaluated yearly until positivisation for a maximum period of 4 years. Positivisation of aTWI was observed in 312 children (94%). The weight, height/length and their respective percentiles at birth and at the time of positivisation of aTWI and weeks of gestation at birth were collected.

RESULTS

Positivisation of aTWI occurred at a mean age of 13.0±2.0 years. When aTWI became positive, the majority of children had a height between 51° and 75° or over the 75° percentile. At the multivariate logistic regression analysis height, weight, percentiles of height and weight at the time of positivisation were identified as the strongest independent predictors of the positivisation of aTWI. No correlation was found for prematurity and anthropometrics characteristics at birth.

CONCLUSIONS

ATWI is a common feature of pediatric ECG, usually regressing with age. Height, weight, percentiles of height and weight at the time of positivisation were identified as determinants of TWI positivisation. These simple anthropometric characteristics should be used in addition to chronological age in order to interpret aTWI in children.

Asthma prevalence, lung and cardiovascular function in adolescents born preterm

Our main objective was to study respiratory evolution and pulmonary and cardiac function in adolescents born preterm in the post-surfactant era. Observational cross-sectional study, comparing very preterm (< 32 weeks) and moderately-late preterm adolescents (≥ 32 weeks) (74 each group). We recorded respiratory symptoms, spirometry and functional echocardiogram. Very preterm adolescents required more respiratory admissions (45.9% vs. 28.4%) (p = 0.03, OR 2.1, CI95% 1.1–4.2) and had more current asthma (21.6% vs. 9.5%, p = 0.04, OR 2.3, CI95% 1.1–5.2). Preterm subjects with intrauterine growth restriction (IUGR) presented lower FEV₁ (88.7 ± 13.9 vs. 95.9 ± 13.3, p = 0.027) and lower FVC (88.2 ± 13.6 vs. 95.5 ± 13.3, p = 0.025). When assessing right ventricle, very preterm showed a greater E/E’ ratio (p = 0.02) and longer myocardial performance index (MPI) (p = 0.001). Adolescents with IUGR showed less shortening fraction (p = 0.016), worse E/E′ ratio (p = 0.029) and longer MPI (p = 0.06). Regarding left ventricle, very preterm showed less E′ wave velocity (p = 0.03), greater E/E′ ratio (p = 0.005) and longer MPI (p < 0.001). Gestational age < 32 weeks is independently associated with current asthma in adolescence. Children 13–14 years old born very preterm required more respiratory admissions and had poorer diastolic and global function of both ventricles. IUGR is a risk factor for poorer lung function in preterm adolescents, regardless gestational age.

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

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

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN12612000995875.

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

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

Respiratory and cardiopulmonary limitations to aerobic exercise capacity in adults born preterm

Adults born preterm, regardless of whether they develop bronchopulmonary dysplasia, have underdeveloped respiratory and cardiopulmonary systems. The resulting impaired respiratory and cardiopulmonary systems are inadequate for the challenges imposed by aerobic exercise, which is exacerbated by the presence of bronchopulmonary dysplasia. Thus the respiratory and cardiopulmonary systems of these preterm individuals may be the most influential contributors to the significantly lower aerobic exercise capacity compared with their term born counterparts. The precise underlying cause(s) of the lower aerobic exercise capacity in adults born preterm is not entirely known but could be a number of interrelated parameters including mechanical ventilatory constraints, impaired pulmonary gas exchange efficiency, and excessive cardiopulmonary pressures. Likewise, additional aspects, such as impaired cardiovascular function and altered muscle bioenergetics, may play additional roles in limiting aerobic exercise capacity. Whether or not all or some of these aspects are present in adults born preterm and precisely how they may contribute to the lower aerobic exercise capacity are only beginning to be systematically explored. The purpose of this mini-review is to outline what is currently known about the respiratory and cardiopulmonary limitations during exercise in this population and to identify key areas where additional knowledge will help to advance this area. Additionally, where possible, we highlight the similarities and differences between obstructive lung disease resulting from preterm birth and chronic obstructive pulmonary disease (COPD) as the physiology and pathophysiology of these two forms of obstructive lung disease may not be identical.

Electrocardiographic features at rest and during exercise in young adults born preterm below 30 weeks of gestation

BACKGROUND

Preterm birth has adverse consequences on the cardiovascular system. Whether premature birth is associated with conduction and repolarisation abnormalities past childhood and into adulthood still needs to be demonstrated.

METHODS

We analyzed the ECG of young adults (23.9 ± 3.1 years) born term (≥37 weeks, n = 53) and preterm (<30 weeks, n = 49) at rest, peak exercise and 3 min into recovery during an exercise test on a cycle ergometer. We measured PR, QRS and QT intervals, calculated the corrected QT (QTc), and determined blood calcium, magnesium, potassium and fasting glucose.

RESULTS

Mean gestational age was 39.7 ± 1.1 and 27.3 ± 1.3 weeks for the term and the preterm groups, respectively. Apart from an increased heart rate at rest in individuals born preterm, no significant difference was found between both groups for any other ECG parameters at rest. None of the participants had a severely prolonged QTc (>500 ms) at rest; exercise revealed severely prolonged QTc in two participants including one in the preterm group. The use of QT-prolonging medications did not influence ECG parameters in either groups.

CONCLUSIONS

We observed no significant difference in electrocardiographic measurements between young adults born preterm and term. Current results do not support avoidance of QT-prolonging medications in individuals born preterm.

IMPACT

Preterm birth is associated with adverse cardiovascular consequences in early adulthood, but controversial evidence exists regarding differences in electrocardiographic features between young individuals born term and preterm.This study aims to assess the differences in electrocardiographic features between young adults born term and preterm, at rest and during exercise training.In contrast with previously published data, we observed no significant difference in electrocardiographic measurements between young adults born preterm and term.Our study does not support that preterm birth itself exposes young adults to a higher risk of QT prolongation.Current results do not support avoidance of QT-prolonging medications in individuals born preterm.

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

CONTEXT

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

OBJECTIVE

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

DATA SOURCES

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

STUDY SELECTION

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

DATA EXTRACTION

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

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

Importance

Premature birth is associated with substantially higher lifetime risk for cardiovascular disease, including arrhythmia, ischemic disease, and heart failure, although the underlying mechanisms are poorly understood.

Objective

To characterize cardiac structure and function in adolescents and young adults born preterm using cardiac magnetic resonance imaging (MRI).

Design, Setting, and Participants

This cross-sectional cohort study at an academic medical center included adolescents and young adults born moderately to extremely premature (20 in the adolescent cohort born from 2003 to 2004 and 38 in the young adult cohort born in the 1980s and 1990s) and 52 age-matched participants who were born at term and underwent cardiac MRI. The dates of analysis were February 2016 to October 2019.

Exposures

Premature birth (gestational age ≤32 weeks) or birth weight less than 1500 g.

Main Outcomes and Measures

Main study outcomes included MRI measures of biventricular volume, mass, and strain.

Results

Of 40 adolescents (24 [60%] girls), the mean (SD) age of participants in the term and preterm groups was 13.3 (0.7) years and 13.0 (0.7) years, respectively. Of 70 adults (43 [61%] women), the mean (SD) age of participants in the term and preterm groups was 25.4 (2.9) years and 26.5 (3.5) years, respectively. Participants from both age cohorts who were born prematurely had statistically significantly smaller biventricular cardiac chamber size compared with participants in the term group: the mean (SD) left ventricular end-diastolic volume index was 72 (7) vs 80 (9) and 80 (10) vs 92 (15) mL/m2 for adolescents and adults in the preterm group compared with age-matched participants in the term group, respectively (P < .001), and the mean (SD) left ventricular end-systolic volume index was 30 (4) vs 34 (6) and 32 (7) vs 38 (8) mL/m2, respectively (P < .001). Stroke volume index was also reduced in adolescent vs adult participants in the preterm group vs age-matched participants in the term group, with a mean (SD) of 42 (7) vs 46 (7) and 48 (7) vs 54 (9) mL/m2, respectively (P < .001), although biventricular ejection fractions were preserved. Biventricular mass was statistically significantly lower in adolescents and adults born preterm: the mean (SD) left ventricular mass index was 39.6 (5.9) vs 44.4 (7.5) and 40.7 (7.3) vs 49.8 (14.0), respectively (P < .001). Cardiac strain analyses demonstrated a hypercontractile heart, primarily in the right ventricle, in adults born prematurely.

Conclusions and Relevance

In this cross-sectional study, adolescents and young adults born prematurely had statistically significantly smaller biventricular cardiac chamber size and decreased cardiac mass. Although function was preserved in both age groups, these morphologic differences may be associated with elevated lifetime cardiovascular disease risk after premature birth.

The fetal inflammatory response syndrome: the origins of a concept, pathophysiology, diagnosis, and obstetrical implications

The fetus can deploy a local or systemic inflammatory response when exposed to microorganisms or, alternatively, to non-infection-related stimuli (e.g., danger signals or alarmins). The term "Fetal Inflammatory Response Syndrome" (FIRS) was coined to describe a condition characterized by evidence of a systemic inflammatory response, frequently a result of the activation of the innate limb of the immune response. FIRS can be diagnosed by an increased concentration of umbilical cord plasma or serum acute phase reactants such as C-reactive protein or cytokines (e.g., interleukin-6). Pathologic evidence of a systemic fetal inflammatory response indicates the presence of funisitis or chorionic vasculitis. FIRS was first described in patients at risk for intraamniotic infection who presented preterm labor with intact membranes or preterm prelabor rupture of the membranes. However, FIRS can also be observed in patients with sterile intra-amniotic inflammation, alloimmunization (e.g., Rh disease), and active autoimmune disorders. Neonates born with FIRS have a higher rate of complications, such as early-onset neonatal sepsis, intraventricular hemorrhage, periventricular leukomalacia, and death, than those born without FIRS. Survivors are at risk for long-term sequelae that may include bronchopulmonary dysplasia, neurodevelopmental disorders, such as cerebral palsy, retinopathy of prematurity, and sensorineuronal hearing loss. Experimental FIRS can be induced by intra-amniotic administration of bacteria, microbial products (such as endotoxin), or inflammatory cytokines (such as interleukin-1), and animal models have provided important insights about the mechanisms responsible for multiple organ involvement and dysfunction. A systemic fetal inflammatory response is thought to be adaptive, but, on occasion, may become dysregulated whereby a fetal cytokine storm ensues and can lead to multiple organ dysfunction and even fetal death if delivery does not occur ("rescued by birth"). Thus, the onset of preterm labor in this context can be considered to have survival value. The evidence so far suggests that FIRS may compound the effects of immaturity and neonatal inflammation, thus increasing the risk of neonatal complications and long-term morbidity. Modulation of a dysregulated fetal inflammatory response by the administration of antimicrobial agents, anti-inflammatory agents, or cell-based therapy holds promise to reduce infant morbidity and mortality.

The LifeCycle Project-EU Child Cohort Network: a federated analysis infrastructure and harmonized data of more than 250,000 children and parents

Early life is an important window of opportunity to improve health across the full lifecycle. An accumulating body of evidence suggests that exposure to adverse stressors during early life leads to developmental adaptations, which subsequently affect disease risk in later life. Also, geographical, socio-economic, and ethnic differences are related to health inequalities from early life onwards. To address these important public health challenges, many European pregnancy and childhood cohorts have been established over the last 30 years. The enormous wealth of data of these cohorts has led to important new biological insights and important impact for health from early life onwards. The impact of these cohorts and their data could be further increased by combining data from different cohorts. Combining data will lead to the possibility of identifying smaller effect estimates, and the opportunity to better identify risk groups and risk factors leading to disease across the lifecycle across countries. Also, it enables research on better causal understanding and modelling of life course health trajectories. The EU Child Cohort Network, established by the Horizon2020-funded LifeCycle Project, brings together nineteen pregnancy and childhood cohorts, together including more than 250,000 children and their parents. A large set of variables has been harmonised and standardized across these cohorts. The harmonized data are kept within each institution and can be accessed by external researchers through a shared federated data analysis platform using the R-based platform DataSHIELD, which takes relevant national and international data regulations into account. The EU Child Cohort Network has an open character. All protocols for data harmonization and setting up the data analysis platform are available online. The EU Child Cohort Network creates great opportunities for researchers to use data from different cohorts, during and beyond the LifeCycle Project duration. It also provides a novel model for collaborative research in large research infrastructures with individual-level data. The LifeCycle Project will translate results from research using the EU Child Cohort Network into recommendations for targeted prevention strategies to improve health trajectories for current and future generations by optimizing their earliest phases of life.

Early Pulmonary Vascular Disease in Young Adults Born Preterm

Rationale: Premature birth affects 10% of live births in the United States and is associated with alveolar simplification and altered pulmonary microvascular development. However, little is known about the long-term impact prematurity has on the pulmonary vasculature.Objectives: Determine the long-term effects of prematurity on right ventricular and pulmonary vascular hemodynamics.Methods: Preterm subjects (n = 11) were recruited from the Newborn Lung Project, a prospectively followed cohort at the University of Wisconsin-Madison, born preterm with very low birth weight (≤1,500 g; average gestational age, 28 wk) between 1988 and 1991. Control subjects (n = 10) from the same birth years were recruited from the general population. All subjects had no known adult cardiopulmonary disease. Right heart catheterization was performed to assess right ventricular and pulmonary vascular hemodynamics at rest and during hypoxic and exercise stress.Measurements and Main Results: Preterm subjects had higher mean pulmonary arterial pressures (mPAPs), with 27% (3 of 11) meeting criteria for borderline pulmonary hypertension (mPAP, 19-24 mm Hg) and 18% (2 of 11) meeting criteria for overt pulmonary hypertension (mPAP ≥ 25 mm Hg). Pulmonary vascular resistance and elastance were higher at rest and during exercise, suggesting a stiffer vascular bed. Preterm subjects were significantly less able to augment cardiac index or right ventricular stroke work during exercise. Among neonatal characteristics, total ventilatory support days was the strongest predictor of adult pulmonary pressure.Conclusions: Young adults born preterm demonstrate early pulmonary vascular disease, characterized by elevated pulmonary pressures, a stiffer pulmonary vascular bed, and right ventricular dysfunction, consistent with an increased risk of developing pulmonary hypertension.

Early impact of moderate preterm birth on the structure, function and gene expression of conduit arteries

NEW FINDINGS

What is the central question of this study? What is the immediate impact of moderate preterm birth on the structure and function of major conduit arteries using a pre-clinical sheep model? What is the main finding and its importance? Postnatal changes in conduit arteries, including a significant decrease in collagen within the thoracic aortic wall (predominately males), narrowed carotid arteries, reduced aortic systolic blood flow, and upregulation of the mRNA expression of cell adhesion and inflammatory markers at 2 days of age in preterm lambs compared to controls, may increase the risk of cardiovascular impairment in later life.

ABSTRACT

The aim of this work was to compare the structure and function of the conduit arteries of moderately preterm and term-born lambs and to determine whether vascular injury-associated genes were upregulated. Time-mated ewes were induced to deliver either preterm (132 ± 1 days of gestation; n = 11 females and n = 10 males) or at term (147 ± 1 days of gestation; n = 10 females and n = 5 males). Two days after birth, ultrasound imaging of the proximal ascending aorta, main, right and left pulmonary arteries, and right and left common carotid arteries was conducted in anaesthetized lambs. Lambs were then killed and segments of the thoracic aorta and left common carotid artery were either snap frozen for real-time PCR analyses or immersion-fixed for histological quantification of collagen, smooth muscle and elastin within the medial layer. Overall there were few differences in vascular structure between moderately preterm and term lambs. However, there was a significant decrease in the proportion of collagen within the thoracic aortic wall (predominantly in males), narrowing of the common carotid arteries and a reduction in peak aortic systolic blood flow in preterm lambs. In addition, there was increased mRNA expression of the cell adhesion marker P-selectin in the thoracic aortic wall and the pro-inflammatory marker IL-1β in the left common carotid artery in preterm lambs, suggestive of postnatal vascular injury. Early postnatal differences in the function and structure of conduit arteries and evidence of vascular injury in moderately preterm offspring may place them at greater risk of cardiovascular impairment later in life.

Prenatal and Postnatal Cardiac Development in Offspring of Hypertensive Pregnancies

Background

Pregnancy complications such as preterm birth and fetal growth restriction are associated with altered prenatal and postnatal cardiac development. We studied whether there were changes related specifically to pregnancy hypertension.

Methods and Results

Left and right ventricular volumes, mass, and function were assessed at birth and 3 months of age by echocardiography in 134 term‐born infants. Fifty‐four had been born to mothers who had normotensive pregnancy and 80 had a diagnosis of preeclampsia or pregnancy‐induced hypertension. Differences between groups were interpreted, taking into account severity of pregnancy disorder, sex, body size, and blood pressure. Left and right ventricular mass indexed to body surface area (LVMI and RVMI) were similar in both groups at birth (LVMI 20.9±3.7 versus 20.6±4.0 g/m², P=0.64, RVMI 17.5±3.7 versus 18.1±4.7 g/m², P=0.57). However, right ventricular end diastolic volume index was significantly smaller in those born to hypertensive pregnancy (16.8±5.3 versus 12.7±4.7 mL/m², P=0.001), persisting at 3 months of age (16.4±3.2 versus 14.4±4.8 mL/m², P=0.04). By 3 months of age these infants also had significantly greater LVMI and RVMI (LVMI 24.9±4.6 versus 26.8±4.9 g/m², P=0.04; RVMI 17.1±4.2 versus 21.1±3.9 g/m², P<0.001). Differences in RVMI and right ventricular end diastolic volume index at 3 months, but not left ventricular measures, correlated with severity of the hypertensive disorder. No differences in systolic or diastolic function were evident.

Conclusions

Infants born at term to a hypertensive pregnancy have evidence of both prenatal and postnatal differences in cardiac development, with right ventricular changes proportional to the severity of the pregnancy disorder. Whether differences persist long term as well as their underlying cause and relationship to increased cardiovascular risk requires further study.

Repair of isolated atrial septal defect in infants less than 12 months improves symptoms of chronic lung disease or shunt-related pulmonary hypertension

INTRODUCTION

Infants with isolated atrial septal defects are usually minimally symptomatic, and repair is typically performed after infancy. Early repair may be considered if there is high pulmonary blood flow and reduced respiratory reserve or early signs of pulmonary hypertension. Our aim was to review the characteristics and outcomes of a cohort of patients who underwent infant repair at our institute.

METHODS

The study included 56 infants (28 female, 19 trisomy 21) with isolated atrial septal defect (age: 8 months (1.5-12), weight: 6 kg (2.8-7.5), echo Qp/Qs: 1.9 ± 0.1) who underwent surgical closure (20 fenestrated). Three groups were identified: 1) chronic lung disease and pulmonary hypertension (group A: n = 28%); 2) acutely unwell infants with pulmonary hypertension but no chronic lung disease (group B: n = 20, 36%); and 3) infants with refractory congestive heart failure without either pulmonary hypertension or chronic lung disease (group C: n = 9, 16%).

RESULTS

Post-operatively, pulmonary hypertension infants (47/56) showed improvement in tricuspid annular plane systolic excursion z-score (p < 0.001) and right ventricular systolic/diastolic duration ratio (p < 0.05). All ventilator (14.3%) or oxygen-dependent (31.6%) infants could be weaned within 2 weeks after repair. One year later, weight z-score increased in all patients and by +1 in group A, +1.3 in group B and +2 in group C. Over a median follow-up of 1.4 years, three patients died, four patients continued to have pulmonary hypertension evidence and two remained on targeted pulmonary hypertension therapy.

CONCLUSION

Atrial septal defect repair within the first year may improve the clinical status and growth in infants with early signs of pulmonary hypertension or those requiring respiratory support and facilitate respiratory management.

Lung function and pulmonary vascular resistance are not associated in 6-year-old children born extremely preterm

AIM

Children born preterm are at increased risk of reduced lung function. The aim was to test whether lung function was associated with pulmonary vascular resistance.

METHODS

Participants were recruited from a population-based cohort born in 2004-2007. Lung function was assessed with spirometry after administration of a beta2-agonist. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁ ) were determined. Estimations of pulmonary vascular resistance, arterial dimensions, right ventricular wall thickness, sphericity, and systolic (TAPSE) and diastolic functions were performed with echocardiography. Adjusted regression analyses were used to study associations.

RESULTS

Sixty-six children (33 boys) born at 22-26 weeks of gestational age (birthweights 460-1134 g) were assessed at a mean age of 6.7 years. Despite large variations in lung function with FVC z-scores ranging from -4.6 to +2.8, there were no associations between lung function and pulmonary arterial pressure, right ventricular structure or function. Children with higher FVC z-scores (r = .52, β = .55 mm, P = .015) and higher FEV₁ z-scores (r = .58, β = .73 mm, P = .001) exhibited larger pulmonary arteries.

CONCLUSION

In children born extremely preterm, lung function was not associated with pulmonary vascular resistance. Routine echocardiographic evaluation of extremely preterm children may not be indicated at age 6.5 years.

Myocardial peak systolic velocity-a tool for cardiac screening of HIV-exposed uninfected children

HIV-uninfected children exposed prenatally to the virus and to prophylactic antiretroviral therapy are at an uncertain risk of long-term myocardial dysfunction. This study aimed to analyse the structure and function of their ventricles and to identify potential screening tools for this at-risk population. One hundred and fifteen children (77 exposed vs 38 controls) aged between 2.7 and 16.2 years were included. An echocardiographic study was performed where both ventricles' dimensions and systolic functions were evaluated. In the left ventricle, parameters related to diastolic function were also analysed. Tissue Doppler values were determined in the basal state and after passive leg raising. Serologic analysis of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) was carried out. The two groups had identical ventricular sizes and left ventricular diastolic functions. However, contractility assessed by myocardial peak systolic velocity was significantly inferior in the exposed group. These systolic echocardiographic differences were present despite similar values of NT-proBNP in both groups.Conclusion: HIV-exposed uninfected children may be vulnerable to ventricular systolic dysfunction at long term. Cardiovascular surveillance and periodic monitoring of biventricular function are therefore recommended. Myocardial peak systolic velocity may be a useful screening tool for this purpose.What is Known:• Previous studies on HIV-exposed uninfected children subjected prenatally to antiretroviral therapy have alerted to potential long-term cardiovascular toxicity effects on the left ventricle.What is New:• The study gives new insights on ventricular function and morphology in HIV-exposed uninfected children.• Myocardial peak systolic velocities are significantly inferior in this paediatric sub-group, therefore long-term cardiac surveillance is recommended.

Early life undernutrition reduces maximum treadmill running capacity in adulthood in mice

Undernutrition during early life causes chronic disease with specific impairments to the heart and skeletal muscle. The purpose of this study was to determine the effects of early life undernutrition on adult exercise capacity as a result of cardiac and skeletal muscle function. Pups were undernourished during gestation (GUN) or lactation (PUN) using a cross-fostering nutritive mouse model. At postnatal day 21, all mice were weaned and refed a control diet. At postnatal day 67, mice performed a maximal treadmill test. Echocardiography and Doppler blood flow analysis was performed at postnatal day 72, following which skeletal muscle cross-sectional area (CSA) and fiber type were determined. Maximal running capacity was reduced (diet: P = 0.0002) in GUN and PUN mice. Left ventricular mass (diet: P = 0.03) and posterior wall thickness during systole (diet × sex: P = 0.03) of GUN and PUN mice was reduced, causing PUN mice to have reduced (diet: P = 0.04) stroke volume. Heart rate of GUN mice showed a trend (diet: P = 0.07) towards greater resting values than other groups. PUN mice had greater CSA of soleus fibers. PUN had a reduced (diet: P = 0.03) proportion of type-IIX fibers in the extensor digitorum longus (EDL) and a greater (diet: P = 0.008) percentage of type-IIB fibers in the EDL. In conclusion, gestational and postnatal undernourishment impairs exercise capacity.

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

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

European Respiratory Society guideline on long-term management of children with bronchopulmonary dysplasia

This document provides recommendations for monitoring and treatment of children in whom bronchopulmonary dysplasia (BPD) has been established and who have been discharged from the hospital, or who were >36 weeks of postmenstrual age. The guideline was based on predefined Population, Intervention, Comparison and Outcomes (PICO) questions relevant for clinical care, a systematic review of the literature and assessment of the evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. After considering the balance of desirable (benefits) and undesirable (burden, adverse effects) consequences of the intervention, the certainty of the evidence, and values, the task force made conditional recommendations for monitoring and treatment of BPD based on very low to low quality of evidence. We suggest monitoring with lung imaging using ionising radiation in a subgroup only, for example severe BPD or recurrent hospitalisations, and monitoring with lung function in all children. We suggest to give individual advice to parents regarding daycare attendance. With regards to treatment, we suggest the use of bronchodilators in a subgroup only, for example asthma-like symptoms, or reversibility in lung function; no treatment with inhaled or systemic corticosteroids; natural weaning of diuretics by the relative decrease in dose with increasing weight gain if diuretics are started in the neonatal period; and treatment with supplemental oxygen with a saturation target range of 90-95%. A multidisciplinary approach for children with established severe BPD after the neonatal period into adulthood is preferable. These recommendations should be considered until new and urgently needed evidence becomes available.

Preventing disease in the 21st century: early breast milk exposure and later cardiovascular health in premature infants

Cardiovascular health of premature infants reaching early adulthood is an area of ongoing research. There is emerging evidence delineating the challenges faced by those individuals. Young adults born premature demonstrate a unique cardiac phenotype characterized by reduced biventricular volume, relatively lower systolic and diastolic function, and a disproportionate increase in muscle mass. This may clinically manifest by an increased risk of cardiovascular incidents, hypertension, and reduced exercise tolerance. Those consequences appear to result from early postnatal cardiac remodeling due to premature birth and associated co-morbidities. Recent evidence suggests that early exposure to breast milk slows down or even arrests those pathophysiological changes, thereby mitigating the long-term adverse effects of premature birth on cardiovascular health. In this review article, we discuss the role of breast milk in preventing early adulthood cardiovascular disease in infants born premature. We explore the emerging evidence and examine the possible mechanistic pathways mediating this phenomenon. Furthermore, we aim to demonstrate the vital role of early breast milk exposure in preventing cardiovascular disease in preterm infants.

When should cardiovascular prevention begin? The importance of antenatal, perinatal and primordial prevention

Cardiovascular diseases represent a major health problem, being one of the leading causes of morbidity and mortality worldwide. Therefore, in this scenario, cardiovascular prevention plays an essential role although it is difficult to establish when promoting and implementing preventive strategies. However, there is growing evidence that prevention should start even before birth, during pregnancy, aiming to avoid the onset of cardiovascular risk factors, since events that occur early in life have a great impact on the cardiovascular risk profile of an adult. The two pillars of this early preventive strategy are nutrition and physical exercise, together with prevention of cardio-metabolic diseases during pregnancy. This review attempts to gather the growing evidence of the benefits of antenatal, perinatal and primordial prevention, discussing also the possibility to reverse or to mitigate the cardiovascular profile developed in the initial stages of life. This could pave the way for future research, investigating the optimal time and duration of these preventing measures, their duration and maintenance in adulthood, and the most effective interventions according to the different age and guiding in the next years, the best clinical practice and the political strategies to cope with cardiovascular disease.

Nomograms of Fetal Right Ventricular Fractional Area Change by 2D Echocardiography

OBJECTIVES

Fetal right ventricular (RV) function assessment is challenging due to the RV geometry and limitations of in utero assessment. Postnatally, 2D echocardiographic RV fractional area change (FAC) is used to assess RV global systolic function by calculating the percentage of change in RV area from systole to diastole. Reports on FAC are scarce in prenatal life, and nomograms throughout pregnancy are not available. Our aims were (1) to study prenatal RV FAC feasibility and reproducibility and (2) to construct nomograms for RV FAC and end-diastolic (ED) and end-systolic (ES) RV areas from 18 to 41 weeks of gestation.

METHODS

Prospective cohort study including 602 low-risk singleton pregnancies undergoing a fetal echocardiography from 18 to 41 weeks of gestation. RV ED and ES areas were measured following standard recommendations for ventricular dimensions and establishing strict landmarks to identify the different phases of the cardiac cycle. RV FAC was calculated as: ([ED area - ES area]/ED area) × 100. RV FAC intra- and inter-observer reproducibility was evaluated in 45 fetuses by calculating the intraclass correlation coefficient (ICC). Parametric regressions were tested to model each parameter against gestational age (GA) and estimated fetal weight (EFW).

RESULTS

RV areas and FAC were successfully obtained in ∼99% of fetuses with acceptable reproducibility throughout gestation (RV ED area inter-observer ICC [95% CI] 0.96 [0.93-0.98], RV ES area 0.97 [0.94-0.98], and FAC 0.69 [0.44-0.83]). Nomograms were constructed for RV ED and ES areas and FAC. RV areas showed a quadratic and logarithmic increase with GA and EFW, respectively. In contrast, RV FAC showed a slight quadratic decrease throughout gestation (mean RV FAC ranged from 36% at 18 weeks of gestation [10-90th centiles: 25-47%, respectively] to 29% at 41 weeks [10-90th centiles: 18-40%, respectively]). The best models for RV areas and FAC were a second-degree polynomial.

CONCLUSIONS

RV FAC is a feasible and reproducible parameter to assess RV global systolic function in fetal life. We provide reference ranges adjusted by GA and EFW that can be used as normal references for the assessment of RV function in prenatal conditions.

Bronchopulmonary dysplasia

In the absence of effective interventions to prevent preterm births, improved survival of infants who are born at the biological limits of viability has relied on advances in perinatal care over the past 50 years. Except for extremely preterm infants with suboptimal perinatal care or major antenatal events that cause severe respiratory failure at birth, most extremely preterm infants now survive, but they often develop chronic lung dysfunction termed bronchopulmonary dysplasia (BPD; also known as chronic lung disease). Despite major efforts to minimize injurious but often life-saving postnatal interventions (such as oxygen, mechanical ventilation and corticosteroids), BPD remains the most frequent complication of extreme preterm birth. BPD is now recognized as the result of an aberrant reparative response to both antenatal injury and repetitive postnatal injury to the developing lungs. Consequently, lung development is markedly impaired, which leads to persistent airway and pulmonary vascular disease that can affect adult lung function. Greater insights into the pathobiology of BPD will provide a better understanding of disease mechanisms and lung repair and regeneration, which will enable the discovery of novel therapeutic targets. In parallel, clinical and translational studies that improve the classification of disease phenotypes and enable early identification of at-risk preterm infants should improve trial design and individualized care to enhance outcomes in preterm infants.

Bimodal right ventricular dysfunction after postnatal hyperoxia exposure: implications for the preterm heart

Rats exposed to postnatal hyperoxia develop right ventricular (RV) dysfunction, mild pulmonary hypertension, and dysregulated cardiac mitochondrial biogenesis when aged to one year, with the degree of cardiac dysfunction and pulmonary hypertension similar to that previously described in young adults born preterm. Here, we sought to understand the impact of postnatal hyperoxia exposure on RV hemodynamic and mitochondrial function across the life span. In Methods, pups from timed-pregnant Sprague-Dawley rats were randomized to normoxia or hyperoxia [fraction of inspired oxygen (FIO2), 0.85] exposure for the first 14 days of life, a commonly used model of chronic lung disease of prematurity. RV hemodynamic and mitochondrial function were assessed by invasive measurement of RV pressure-volume loops and by high-resolution respirometry at postnatal day 21 (P21), P90, and P365. In Results, at P21, hyperoxia-exposed rats demonstrated severe pulmonary hypertension and RV dysfunction, accompanied by depressed mitochondrial oxidative capacity. However, significant upregulation of mitochondrial biogenesis at P21 as well as improved afterload led to complete RV hemodynamic and mitochondrial recovery at P90. Mitochondrial DNA mutations were significantly higher by P90 and associated with significant late RV mitochondrial and hemodynamic dysfunction at P365. In conclusion, there appears to be a "honeymoon period" where cardiac hemodynamic and mitochondrial function normalizes following postnatal hyperoxia exposure, only to decline again with ongoing aging. This finding may have significant implications if a long-term pulmonary vascular screening program were to be developed for children or adults with a history of severe prematurity. Further investigation into the mechanisms of recovery are warranted.NEW & NOTEWORTHY Premature birth is associated with increased risk for cardiac dysfunction and failure throughout life. Here, we identify bimodal right ventricular dysfunction after postnatal hyperoxia exposure. Mitochondrial biogenesis serves as an early adaptive feature promoting recovery of cardiac hemodynamic and mitochondrial function. However, the accumulation of mitochondrial DNA mutations results in late mitochondrial and right ventricular dysfunction. This bimodal right ventricular dysfunction may have important implications for the development of screening programs in the preterm population.