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

Cardiac Mechanics Evaluation in Preschool-Aged Children with Preterm Birth History: A Speckle Tracking and 4D Echocardiography Study

Background: The premature-born adult population is set to grow significantly, and prematurity has emerged as an important cardiovascular risk factor. We aimed to comprehensively assess cardiac mechanics and function in a cohort of ex-preterm preschoolers. Methods: Ex-preterm children (<30 weeks of gestation), aged 2 to 5 years, underwent transthoracic 2D, speckle-tracking, and 4D echocardiography. The findings were compared with 19 full-term children. Results: Our cohort of 38 children with prematurity history showed a normal morpho-functional echocardiographic assessment. However, compared to controls, the indexed 3D end-diastolic volumes of ventricular chambers were reduced (left ventricle 58.7 ± 11.2 vs. 67.2 ± 8.5 mL/m2; right ventricle 50.3 ± 10.4 vs. 57.7 ± 11 mL/m2; p = 0.02). Left ventricle global and longitudinal systolic function were worse in terms of fraction shortening (32.9% ± 6.8 vs. 36.5% ± 5.4; p = 0.05), ejection fraction (59.2% ± 4.3 vs. 62.3% ± 3.7; p = 0.003), and global longitudinal strain (-23.6% ± 2.4 vs. -25.5% ± 1.7; p = 0.003). Finally, we found a reduced left atrial strain (47.4% ± 9.7 vs. 54.9% ± 6.8; p = 0.004). Conclusions: Preschool-aged ex-preterm children exhibited smaller ventricles and subclinical impairment of left ventricle systolic and diastolic function compared to term children. Long-term follow-up is warranted to track the evolution of these findings.

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.

Risk factors for isolated atrial septal defect secundum morbidity

Atrial septal defect secundum is a common type of congenital heart defect and even more common among children born premature. The aim of this study was to assess premature birth as a potential associated risk factors for cardiac morbidity in children with isolated ASD II. In this retrospective national registry-based case-control study all children born in Sweden between 2010 and 2015 with an isolated ASD II diagnosis were included. Association between premature birth and cardiac morbidity in children with isolated ASD II was assessed by different outcomes-models using conditional logistic regression and adjustments were made for confounding factors. Overall, 11% of children with an isolated ASD II received treatment for heart failure. Down syndrome was the only independent risk factors for associated with cardiac morbidity in children with ASD II (OR = 2.25 (95%CI 1.25-4.07). Preterm birth in children was not associated with an increased risk of ASD II cardiac morbidity.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Echocardiography Assessment of Left Ventricular Function in Extremely Preterm Infants, Born at Less Than 28 Weeks' Gestation, With Bronchopulmonary Dysplasia and Systemic Hypertension

BACKGROUND

The survival of smaller and more immature premature infants has been associated with lifelong cardiorespiratory comorbidities. Infants with bronchopulmonary dysplasia (BPD) undergo routine screening echocardiography to evaluate for development of chronic pulmonary hypertension, a late manifestation of pulmonary vascular disease.

METHODS

Our aim was to evaluate left ventricular (LV) performance in infants with BPD and pulmonary vascular disease who developed systemic hypertension. We hypothesized that infants with hypertension were more likely to have impaired LV performance. We present a single-center cross-sectional study of premature infants born at less than 28 0/7 weeks' gestational age with a clinical diagnosis of BPD. Infants were categorized by the systolic arterial pressure (SAP) at time of echocardiography as hypertensive (SAP ≥90 mm Hg) or normotensive (SAP <90 mm Hg). Sixty-four patients were included.

RESULTS

Infants with hypertension showed altered LV diastolic function with prolonged tissue Doppler imaging-derived isovolumic relaxation time (54.2 ± 5.1 vs 42.9 ± 8.2, P < .001), lower E:A, and higher E:e'. Indices of left heart volume/pressure loading (left atrium:aorta and LV end-diastolic volume [6.1 ± 2 vs 4.2 ± 1.2, P < .001]) were also higher in the hypertensive group. Finally, infants in the hypertensive group had higher pulmonary vascular resistance index (4.42 ± 1.1 vs 3.69 ± 0.8, P = .004).

CONCLUSIONS

We conclude that extremely preterm infants with BPD who develop systemic hypertension are at risk of abnormal LV diastolic dysfunction. Increased pulmonary vascular resistance index in the hypertensive group may relate to pulmonary venous hypertension secondary to LV dysfunction. This is an important consideration in this cohort when selecting the physiologically most appropriate treatment.

Effect of preterm birth on growth and blood pressure in adulthood in the Pelotas 1993 cohort

BACKGROUND

Preterm birth has been associated with increased risk of hypertension and cardiovascular disease later in adulthood, attributed to cardiovascular and metabolic alterations in early life. However, there is paucity of evidence from low- and middle-income countries (LMICs).

METHODS

We investigated the differences between preterm (<37 weeks gestational age) and term-born individuals in birth length and weight as well as adult (18 and 20 years) height, weight and blood pressure in the Brazilian 1993 Pelotas birth cohort using linear regressions. Analyses were adjusted for the maternal weight at the beginning of pregnancy and maternal education and family income at childbirth. Additional models were adjusted for body mass index (BMI) and birthweight. Separate analyses were run for males and females. The complete sample was analysed with an interaction term for sex.

RESULTS

Of the 3585 babies included at birth, 3010 were followed up in adulthood at 22 years. Preterm participants had lower length and weight at birth. This difference remained for male participants in adulthood, but female participants were no shorter than their term counterparts by 18 years of age. At 22 years, females born preterm had lower blood pressures (systolic blood pressure -1.00 mmHg, 95%CI -2.7, 0.7 mmHg; diastolic blood pressure -1.1 mmHg, 95%CI -2.4, 0.3 mmHg) than females born at term. These differences were not found in male participants.

CONCLUSIONS

In this Brazilian cohort we found contrasting results regarding the association of preterm birth with blood pressure in young adulthood, which may be unique to an LMIC.

Effects of size at birth on health, growth and developmental outcomes in children up to age 18: an umbrella review

BACKGROUND

Size at birth, an indicator of intrauterine growth, has been studied extensively in relation to subsequent health, growth and developmental outcomes. Our umbrella review synthesises evidence from systematic reviews and meta-analyses on the effects of size at birth on subsequent health, growth and development in children and adolescents up to age 18, and identifies gaps.

METHODS

We searched five databases from inception to mid-July 2021 to identify eligible systematic reviews and meta-analyses. For each meta-analysis, we extracted data on the exposures and outcomes measured and the strength of the association.

FINDINGS

We screened 16 641 articles and identified 302 systematic reviews. The literature operationalised size at birth (birth weight and/or gestation) in 12 ways. There were 1041 meta-analyses of associations between size at birth and 67 outcomes. Thirteen outcomes had no meta-analysis.Small size at birth was examined for 50 outcomes and was associated with over half of these (32 of 50); continuous/post-term/large size at birth was examined for 35 outcomes and was consistently associated with 11 of the 35 outcomes. Seventy-three meta-analyses (in 11 reviews) compared risks by size for gestational age (GA), stratified by preterm and term. Prematurity mechanisms were the key aetiologies linked to mortality and cognitive development, while intrauterine growth restriction (IUGR), manifesting as small for GA, was primarily linked to underweight and stunting.

INTERPRETATION

Future reviews should use methodologically sound comparators to further understand aetiological mechanisms linking IUGR and prematurity to subsequent outcomes. Future research should focus on understudied exposures (large size at birth and size at birth stratified by gestation), gaps in outcomes (specifically those without reviews or meta-analysis and stratified by age group of children) and neglected populations.

PROSPERO REGISTRATION NUMBER

CRD42021268843.

Consequences of Preterm Birth: Knowns, Unknowns, and Barriers to Advancing Cardiopulmonary Health

Preterm birth occurs in 10% of all live births and creates challenges to neonatal life, which persist into adulthood. Significant previous work has been undertaken to characterize and understand the respiratory and cardiovascular sequelae of preterm birth, which are present in adulthood, i.e., "late" outcomes. However, many gaps in knowledge are still present and there are several challenges that will make filling these gaps difficult. In this perspective we discuss the obstacles of studying adults born preterm, including (1) the need for invasive (direct) measures of physiologic function; (2) the need for multistate, multinational, and diverse cohorts; (3) lack of socialized medicine in the United States; (4) need for detailed and better-organized birth records; and (5) transfer of neonatal and pediatric knowledge to adult care physicians. We conclude with a discussion on the "future" of studying preterm birth in regards to what may happen to these individuals as they approach middle and older age and how the improvements in perinatal and postnatal care may be changing the phenotypes observed in adults born preterm on or after the year 2000.

Severity of preterm birth and the risk of pulmonary hypertension in childhood: A population-based cohort study in Sweden

BACKGROUND

Preterm birth (<37 completed gestational weeks) has been linked to pulmonary hypertension (PH), but the relationship to severity of preterm birth has not been studied.

OBJECTIVES

We investigated associations between extremely (<28 weeks), very (28-31 weeks), moderately (32-36 weeks) preterm birth, early-term birth (37-38 weeks) and later PH. Additionally, we explored associations between birthweight for gestational age and PH.

METHODS

This registry-based cohort study followed 3.1 million individuals born in Sweden (1987-2016) from 1 up to a maximum of 30 years of age. The outcome was diagnosis or death from PH in national health registers. Adjusted hazard ratios (HR) were estimated using Cox regression analysis. Unadjusted and confounder-adjusted incidence rate differences were also calculated.

RESULTS

Of 3,142,812 individuals, there were 543 cases of PH (1.2 per 100,000 person-years), 153 of which in individuals without malformations. Compared with individuals born at 39 weeks, adjusted HRs with 95% confidence interval (CI) for PH for extremely, moderately, and very preterm birth were 68.78 (95% CI 49.49, 95.57), 13.86 (95% CI 9.27, 20.72) and 3.42 (95% CI 2.46, 4.74), respectively, and for early-term birth 1.74 (1.31, 2.32). HRs were higher in subjects without malformations. There were 90 additional cases of PH per 100,000 person-years in the extremely preterm group (50 after excluding malformations). Very small for gestational age (below 2 SD from estimated birthweight for gestational age and sex) was also associated with increased risk of PH (adjusted HR 2.02, 95% CI 1.14, 3.57).

CONCLUSIONS

We found an inverse association between gestational age and later PH, but the incidence and absolute risks are low. The severity of preterm birth adds clinically relevant information to the assessment of cardiovascular risks in childhood.

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.

Small vulnerable newborns-big potential for impact

Despite major achievements in child survival, the burden of neonatal mortality has remained high and even increased in some countries since 1990. Currently, most neonatal deaths are attributable to being born preterm, small for gestational age (SGA), or with low birthweight (LBW). Besides neonatal mortality, these conditions are associated with stillbirth and multiple morbidities, with short-term and long-term adverse consequences for the newborn, their families, and society, resulting in a major loss of human capital. Prevention of preterm birth, SGA, and LBW is thus critical for global child health and broader societal development. Progress has, however, been slow, largely because of the global community's failure to agree on the definition and magnitude of newborn vulnerability and best ways to address it, to frame the problem attractively, and to build a broad coalition of actors and a suitable governance structure to implement a change. We propose a new definition and a conceptual framework, bringing preterm birth, SGA, and LBW together under a broader umbrella term of the small vulnerable newborn (SVN). Adoption of the framework and the unified definition can facilitate improved problem definition and improved programming for SVN prevention. Interventions aiming at SVN prevention would result in a healthier start for live-born infants, while also reducing the number of stillbirths, improving maternal health, and contributing to a positive economic and social development in the society.

Aerobic Exercise Training Response in Preterm-Born Young Adults with Elevated Blood Pressure and Stage 1 Hypertension: A Randomized Clinical Trial

Rationale: Premature birth is an independent predictor of long-term cardiovascular risk. Individuals affected are reported to have a lower rate of [Formula: see text]o2 at peak exercise intensity ([Formula: see text]o2PEAK) and at the ventilatory anaerobic threshold ([Formula: see text]o2VAT), but little is known about their response to exercise training. Objectives: The primary objective was to determine whether the [Formula: see text]o2PEAK response to exercise training differed between preterm-born and term-born individuals; the secondary objective was to quantify group differences in [Formula: see text]o2VAT response. Methods: Fifty-two preterm-born and 151 term-born participants were randomly assigned (1:1) to 16 weeks of aerobic exercise training (n = 102) or a control group (n = 101). Cardiopulmonary exercise tests were conducted before and after the intervention to measure [Formula: see text]o2PEAK and the [Formula: see text]o2VAT. A prespecified subgroup analysis was conducted by fitting an interaction term for preterm and term birth histories and exercise group allocation. Measurements and Main Results: For term-born participants, [Formula: see text]o2PEAK increased by 3.1 ml/kg/min (95% confidence interval [CI], 1.7 to 4.4), and the [Formula: see text]o2VAT increased by 2.3 ml/kg/min (95% CI, 0.7 to 3.8) in the intervention group versus controls. For preterm-born participants, [Formula: see text]o2PEAK increased by 1.8 ml/kg/min (95% CI, -0.4 to 3.9), and the [Formula: see text]o2VAT increased by 4.6 ml/kg/min (95% CI, 2.1 to 7.0) in the intervention group versus controls. No significant interaction was observed with birth history for [Formula: see text]o2PEAK (P = 0.32) or the [Formula: see text]o2VAT (P = 0.12). Conclusions: The training intervention led to significant improvements in [Formula: see text]o2PEAK and [Formula: see text]o2VAT, with no evidence of a statistically different response based on birth history. Clinical trial registered with www.clinicaltrials.gov (NCT02723552).

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.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

The biventricular contribution to chronic pulmonary hypertension of the extremely premature infant

OBJECTIVE

Evaluate factors associated with significant pulmonary hypertension [PH] (≥2/3 systemic) and its impact on ventricular function at 36 weeks postmenstrual age (PMA).

STUDY DESIGN

Retrospective cohort of infants born at <29 weeks who survived to their echocardiography screening for PH at 36 weeks PMA. Masked experts extracted conventional and speckle-tracking echocardiography [STE] data.

RESULTS

Of 387 infants, 222 were included and 24 (11%) categorized as significant PH. Significant PH was associated with a decrease in tricuspid annular plane systolic excursion (0.79 vs 0.87 cm, p = 0.03), right peak longitudinal strain [pLS] by STE (-19.6 vs -23.1%, p = 0.003) and left pLS (-25.0 vs -22.7%, p = 0.02). The association between biventricular altered function by STE and significant PH persisted after adjustment for potential confounders - LV-pLS (p = 0.007) and RV-pLS (p = 0.01).

CONCLUSION

Our findings are suggestive that premature newborns with significant PH at 36 weeks PMA have a biventricular cardiac involvement to their pathophysiology.

Effect of preterm birth in rats on proliferation and hyperplasia of cardiomyocytes

Aim. To identify the effect of preterm birth on proliferation and hyperplasia of cardiomyocytes in the early postnatal period of ontogenesis in rats.

Materials and methods. Preterm birth (on day 21 and 21.5 of gestation) in Wistar rats was induced by subcutaneous administration of mifepristone. Immunohistochemistry was used to identify and calculate the number of Ki67-positive and Mklp2-positive cardiomyocytes in the left ventricle of preterm and full-term rats on days 1, 2, 3, 4, 5, and 6 of postnatal ontogenesis. Statistical analysis of morphometric parameters was performed using the Shapiro – Wilk test and Mann – Whitney test with the Bonferroni correction.

Results. We revealed an increase in the number of Ki67-positive cardiomyocytes in the left ventricle of the rats: on day 1 of postnatal ontogenesis (in the rats born on day 21 of gestation) and on days 3–5 of postnatal ontogenesis (in the rats born on day 21.5 of gestation). Preterm birth in rats did not result in a change in the number of Mklp2-positive cardiomyocytes in the left ventricular wall.

Conclusion. A change in the pattern of Ki67 expression by cardiomyocytes in the rats born 12 or 24 hours before full term was demonstrated in the early postnatal period of ontogenesis. An isolated increase in Ki67 expression without a change in Mklp2 expression by cardiomyocytes in the left ventricular wall of preterm rats indicates acceleration of cardiomyocyte hypertrophy. Shorter duration of prenatal development is associated with more pronounced morphological and functional rearrangements in the rat myocardium.

The role of human milk feeds on inotrope use in newborn infants with sepsis

Background

Regarding neonatal hypotension, there is no certainty as to whether inotrope properties are beneficial or whether they may be harmful. However, given that the antioxidant content of human milk plays a compensatory role in neonatal sepsis and that human milk feeding has direct effects in modulating the cardiovascular function of sick neonates, this research hypothesized that human milk feeds might predict lower requirements of vasopressors in the management of neonatal septic shock.

Method

Between January 2002 and December 2017, all late preterm and full-term infants attending a neonatal intensive care unit, with clinical and laboratory findings of bacterial or viral sepsis, were identified in a retrospective study. During their first month of life, data on feeding type and early clinical characteristics were collected. A multivariable logistic regression model was constructed to determine the impact of human milk on the use of vasoactive drugs in septic newborns.

Results

322 newborn infants were eligible to participate in this analysis. Exclusively formula-fed infants were more likely to be delivered via C-section, to have a lower birth weight and a lower 1-minute Apgar score than their counterparts. Human milk-fed newborns had 77% (adjusted OR = 0.231; 95% CI: 0.07-0.75) lower odds of receiving vasopressors than exclusively formula-fed newborns.

Conclusion

We report that any human milk feeding is associated with a decrease in the need for vasoactive medications in sepsis-affected newborns. This observation encourages us to undertake further research to determine whether human milk feeds mitigate the use of vasopressors in neonates with sepsis.

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.

Left Ventricular Diastolic Function in Subjects Conceived through Assisted Reproductive Technologies

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

QTc intervals are not prolonged in former ELBW infants at pre-adolescent age

BACKGROUND

Whether preterm birth is associated with cardiac conduction or repolarization abnormalities in later life is still poorly explored, with conflicting data on QTc prolongation in former extreme low birth weight (ELBW, &lt;1000 g) infants.

METHODS

Twelve lead electrocardiograms (ECG) at rest, collected in the PREMATurity as predictor of children's Cardiovascular-renal Health (PREMATCH) study in former ELBW cases and term controls during pre-adolescence (8-14 years) were analyzed on corrected QT time (QTc, Bazett) and QT dispersion (QTd). ECG findings were compared between groups (Mann-Whitney), and associations with clinical and biochemical findings were explored (Spearman). In ELBW cases, associations between QTc and perinatal characteristics (at birth, neonatal stay) were explored (Mann-Whitney, Spearman).

RESULTS

QTc and QTd were similar between 93 ELBW cases and 87 controls [409 (range 360-465) versus 409 (337-460); 40 (0-100) versus 39 (0-110)] ms. Age, height, weight, or body mass index were not associated with the QTc interval, while female sex (median difference 11.4 ms) and lower potassium (r = -0.26) were associated with longer QTc interval. We could not observe any significant association between QTc interval and perinatal characteristics.

CONCLUSIONS

There were no differences in QTc or QTd between ELBW and term controls in ECGs at rest in pre-adolescents.

IMPACT

This study aimed to assess the differences in QTc and QTd intervals between extreme low birth weight infants (ELBW) and term controls in electrocardiographic measurements at rest during pre-adolescence. This analysis confirmed the absence of significant differences in QTc or QTd findings between ELBW cases and term controls, while female sex and lower potassium were associated with a prolonged QTc interval. These data suggest that QTc screening strategies-including for pharmacovigilance-should not differentiate between former ELBW cases and term controls.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02147457.

Evolution of Preterm Infant Nutrition from Breastfeeding to an Exclusive Human Milk Diet: A Review

The benefits of feeding human milk to human infants are well-established. Preterm infants, particularly those born with very low birthweight (VLBW; <1,500 g), are a uniquely vulnerable population at risk for serious, life-threatening complications as well as disruptions in normal growth and development that can affect their lives into adulthood. Feeding VLBW preterm infants an exclusive human milk diet (EHMD) from birth that consists of the mother's own milk or donor human milk plus a nutritional fortifier made exclusively from human milk has been associated with a reduction in morbidity and mortality and improved early growth and developmental metrics. Preliminary evidence suggests that the health benefits of adopting an EHMD (or avoiding cow milk products) early in life may last into adulthood. This review briefly summarizes the history of breastfeeding and describes the available evidence on the benefits of an EHMD among VLBW preterm infants as well as the importance of high-quality manufacturing standards for producing safe and effective human milk-based products.

Exposure to high levels of oxygen in neonatal rats induce a decrease in hemoglobin levels

BACKGROUND

Anemia of prematurity is common in extremely preterm neonates, and oxygen exposure may participate to anemia by inhibiting erythropoietin secretion. We aimed to determine whether hyperoxia exerts an independent role in the occurrence of the anemia of prematurity.

METHODS

Sprague-Dawley pups were exposed to 80% oxygen or room air from days 3 to 10 of life. Main outcome was the difference in hemoglobin and circulating erythropoietin levels in animals exposed to hyperoxia at 10 days of life. We performed a complete blood count analysis using fluorescent laser flow cytometry and measured circulating erythropoietin levels using ELISA.

RESULTS

We found lower hemoglobin in the hyperoxia group, compared to the normoxia group, both in males (70 ± 3 versus 78 ± 2 g/l) and in females (71 ± 2 versus 81 ± 3 g/l) at 10 days of life. Reticulocyte count was not increased in the hyperoxia group. Circulating erythropoietin levels were lower at 10 days of life in the animals exposed to hyperoxia, both in males (33 ± 7 versus 73 ± 6 pg/ml) and in females (37 ± 5 versus 66 ± 3 pg/ml), but were similar at 28 days of life.

CONCLUSION

Neonatal exposure to hyperoxia decreases hematopoiesis in rats.

IMPACT

Mechanisms leading to anemia of prematurity are not well known and their study in humans is complicated due to multiple confounders. This study shows for the first time that exposure to high concentrations of oxygen in the neonatal period decreases hematopoiesis in rats, providing insight on the pathophysiological mechanisms of the anemia of prematurity. This research paves the way for future therapeutic developments aiming to reduce the burden of anemia of prematurity and the necessity of red blood cell transfusions in extremely preterm neonates.

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

Abstract

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% FiO2), 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.

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.

Linking the Perinatal Environment to Neonatal Cardiovascular Outcomes

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

Preconception lifestyle intervention in women with obesity and echocardiographic indices of cardiovascular health in their children

BACKGROUND

Improving maternal lifestyle before conception may prevent the adverse effects of maternal obesity on their children's future cardiovascular disease (CVD) risk. In the current study, we examined whether a preconception lifestyle intervention in women with obesity could alter echocardiographic indices of cardiovascular health in their children.

METHODS

Six years after a randomized controlled trial comparing the effects of a 6-month preconception lifestyle intervention in women with obesity and infertility prior to fertility care to prompt fertility care, 315 of the 341 children conceived within 24 months after randomization were eligible for this study. The intervention was aimed at weight loss (≥5% or until BMI < 29 kg/m²). Children underwent echocardiographic assessment of cardiac structure and function, conducted by a single pediatric cardiologist, blinded to group allocation. Results were adjusted for multiple variables including body surface area, age, and sex in linear regression analyses.

RESULTS

Sixty children (32 girls, 53%) were included, mean age 6.5 years (SD 1.09). Twenty-four children (40%) were born to mothers in the intervention group. Children of mothers from the intervention group had a lower end-diastolic interventricular septum thickness (-0.88 Z-score, 95%CI -1.18 to -0.58), a lower left ventricle mass index (-8.56 g/m², 95%CI -13.09 to -4.03), and higher peak systolic and early diastolic annular velocity of the left ventricle (1.43 cm/s 95%CI 0.65 to 2.20 and 2.39 cm/s 95%CI 0.68 to 4.11, respectively) compared to children of mothers from the control group.

CONCLUSIONS

Children of women with obesity, who underwent a preconception lifestyle intervention, had improved cardiac structure and function; a thinner interventricular septum, lower left ventricle mass, and improved systolic and diastolic tissue Doppler velocities. Despite its high attrition rates, our study provides the first experimental human evidence suggesting that preconception lifestyle interventions may present a method of reducing CVD risk in the next generation.

CLINICAL TRIAL REGISTRATION

LIFEstyle study: Netherlands Trial Register: NTR1530 ( https://www.trialregister.nl/trial/1461 ). This follow-up study was approved by the medical ethics committee of the University Medical Centre Groningen (METC code: 2008/284).

Physiological aspects of cardiopulmonary dysanapsis on exercise in adults born preterm

Progressive improvements in perinatal care and respiratory management of preterm infants have resulted in increased survival of newborns of extremely low gestational age over the past few decades. However, the incidence of bronchopulmonary dysplasia, the chronic lung disease after preterm birth, has not changed. Studies of the long-term follow-up of adults born preterm have shown persistent abnormalities of respiratory, cardiovascular and cardiopulmonary function, possibly leading to a lower exercise capacity. The underlying causes of these abnormalities are incompletely known, but we hypothesize that dysanapsis, i.e. discordant growth and development, in the respiratory and cardiovascular systems is a central structural feature that leads to a lower exercise capacity in young adults born preterm than those born at term. We discuss how the hypothesized system dysanapsis underscores the observed respiratory, cardiovascular and cardiopulmonary limitations. Specifically, adults born preterm have: (1) normal lung volumes but smaller airways, which causes expiratory airflow limitation and abnormal respiratory mechanics but without impacts on pulmonary gas exchange efficiency; (2) normal total cardiac size but smaller cardiac chambers; and (3) in some cases, evidence of pulmonary hypertension, particularly during exercise, suggesting a reduced pulmonary vascular capacity despite reduced cardiac output. We speculate that these underlying developmental abnormalities may accelerate the normal age-associated decline in exercise capacity, via an accelerated decline in respiratory, cardiovascular and cardiopulmonary function. Finally, we suggest areas of future research, especially the need for longitudinal and interventional studies from infancy into adulthood to better understand how preterm birth alters exercise capacity across the lifespan.

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.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Educational Review: The Impact of Perinatal Oxidative Stress on the Developing Kidney

Oxidative stress occurs when there is an imbalance between reactive oxygen species/reactive nitrogen species and antioxidant systems. The interplay between these complex processes is crucial for normal pregnancy and fetal development; however, when oxidative stress predominates, pregnancy related complications and adverse fetal programming such as preterm birth ensues. Understanding how oxidative stress negatively impacts outcomes for the maternal-fetal dyad has allowed for the exploration of antioxidant therapies to prevent and/or mitigate disease progression. In the developing kidney, the negative impact of oxidative stress has also been noted as it relates to the development of hypertension and kidney injury mostly in animal models. Clinical research addressing the implications of oxidative stress in the developing kidney is less developed than that of the neurodevelopmental and respiratory conditions of preterm infants and other vulnerable neonatal groups. Efforts to study the oxidative stress pathway along the continuum of the perinatal period using a team science approach can help to understand the multi-organ dysfunction that the maternal-fetal dyad sustains and guide the investigation of antioxidant therapies to ameliorate the global toxicity. This educational review will provide a comprehensive and multidisciplinary perspective on the impact of oxidative stress during the perinatal period in the development of maternal and fetal/neonatal complications, and implications on developmental programming of accelerated aging and cardiovascular and renal disease for a lifetime.

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.

Cardiac structure and function in very preterm-born adolescents compared to term-born controls: A longitudinal cohort study

BACKGROUND

There is emerging evidence of differences in cardiac structure and function in preterm-born adults and increased risk of heart failure. However, there is a paucity of data in populations who have been exposed to modern intensive care and the impact of perinatal factors is unclear.

AIMS

To compare echocardiographic measures of cardiac structure and function in a regional cohort of 17-year-olds born very preterm compared to term-born peers and the influence of perinatal factors.

STUDY DESIGN

Observational longitudinal cohort study.

SUBJECTS

A regional cohort of ninety-one 17-year-olds born at <32 weeks gestation compared to sixty-two term-born controls.

OUTCOME MEASURES

Echocardiographic measures of cardiac structure and function.

RESULTS

Left ventricular and right atrial volume and left ventricular mass, indexed to body surface area, were significantly smaller in preterm-born adolescents compared to term-born controls even when adjusted for sex. There were no between group differences in cardiac function. Within those born preterm we found a significant association between gestational age and birthweight z-score and measures of cardiac function at 17 years. Within the preterm group, those with a diagnosis of bronchopulmonary dysplasia had higher left ventricular posterior wall thickness, higher mitral deceleration time and lower left atrial area and tricuspid annular plane of systolic excursion.

CONCLUSIONS

Adolescents born very prematurely, who have received modern intensive care, have measurable differences in heart structure compared to their term-born peers but heart function is preserved. For those born preterm, gestational age, birthweight and bronchopulmonary dysplasia are associated with differences in cardiac function.

Cardiovascular impact and sequelae of bronchopulmonary dysplasia

The development, growth, and function of the cardiac, pulmonary, and vascular systems are closely intertwined during both fetal and postnatal life. In utero, placental, environmental, and genetic insults may contribute to abnormal pulmonary alveolarization and vascularization that increase susceptibility to the development of bronchopulmonary dysplasia (BPD) in preterm infants. However, the shared milieu of stressors may also contribute to abnormal cardiac or vascular development in the fetus and neonate, leading to the potential for cardiovascular dysfunction. Further, cardiac or pulmonary maladaptation can potentiate dysfunction in the other organ, amplify the risk for BPD in the neonate, and increase the trajectory for overall neonatal morbidity. Beyond infancy, there is an increased risk for systemic and pulmonary vascular disease including hypertension, as well as potential cardiac dysfunction, particularly within the right ventricle. This review will focus on the cardiovascular antecedents of BPD in the fetus, cardiovascular consequences of preterm birth in the neonate including associations with BPD, and cardiovascular impact of prematurity and BPD throughout the lifespan.

Right Ventricular Structure and Function in Young Adults Born Preterm at Very Low Birth Weight

Being born preterm (PT, <37 weeks gestation) or at very low birth weight (VLBW, <1500 g) is associated with increased rates of cardiopulmonary disorders in childhood. As survivors age, late cardiac effects, including right ventricular (RV) remodelling and occult pulmonary hypertension are emerging. In this population-based study, we aimed to investigate right heart structure and function in young adults born PT at VLBW compared to normal-weight term-born controls. The New Zealand VLBW Study has followed all infants born in 1986 with birth weight <1500 g. All were born preterm from 24 to 37 weeks. A total of 229 (71% of survivors) had echocardiograms aged 26–30 years which were compared to age-matched, term-born, normal-weight controls (n = 100). Young adults born preterm at very low birth weight exhibited smaller RV dimensions compared to term-born peers. Standard echocardiographic measures of RV function did not differ, but mildly reduced function was detected by RV longitudinal strain. This difference was related to birth weight and gestational age but not lung function or left ventricular function. Echocardiographic strain imaging may be an important tool to detect differences in RV function preterm and VLBW.

Safety, Feasibility, and Impact of Enalapril on Cardiorespiratory Physiology and Health in Preterm Infants with Systemic Hypertension and Left Ventricular Diastolic Dysfunction

Neonatal hypertension has been increasingly recognized in premature infants with bronchopulmonary dysplasia (BPD); of note, a sub-population of these infants may have impaired left ventricular (LV) diastolic function, warranting timely treatment to minimize long term repercussions. In this case series, enalapril, an angiotensin-converting enzyme (ACE) inhibitor, was started in neonates with systemic hypertension and echocardiography signs of LV diastolic dysfunction. A total of 11 patients were included with birth weight of 785 ± 239 grams and gestational age of 25.3 (24, 26.1) weeks. Blood pressure improvement was noticed within 2 weeks of treatment. Improvement in LV diastolic function indices were observed with a reduction in Isovolumic Relaxation Time (IVRT) from 63.1 ± 7.2 to 50.9 ± 7.4 msec and improvement in the left atrium size indexed to aorta (LA:Ao) from1.73 (1.43, 1.88) to 1.23 (1.07, 1.29). Neonatal systemic hypertension is often underappreciated in ex-preterm infants and may be associated with important maladaptive cardiac changes with long term implications. It is biologically plausible that identifying and treating LV diastolic dysfunction in neonates with systemic hypertension may have a positive modulator effect on cardiovascular health in childhood and beyond.

Reduced Exercise Capacity in Adults Born Very Low Birth Weight: A Population-Based Cohort Study

RATIONALE

Population-based data regarding the consequences of very low birth weight (VLBW) and bronchopulmonary dysplasia (BPD) on adult exercise capacity is limited.

OBJECTIVES

To compare exercise capacity in a national VLBW cohort with term-born controls and explore factors contributing to the differences.

METHODS

At 26-30 years of age, 228 VLBW survivors and 100 controls underwent lung function tests, cardiopulmonary exercise testing and assessment of resting cardiac structure/function using echocardiography. Data on self-reported physical activity were collected.

MEASUREMENTS AND MAIN RESULTS

Compared with controls, VLBW adults demonstrated reduced oxygen uptake, work rate and oxygen pulse at peak exercise (9.3%, 10.7%, 10.8% lower, respectively) and earlier anaerobic threshold (all p<0.0001), with all mean values within normal range. VLBW survivors showed reduced physical activity, impaired lung function (reduced FEV1, FEV1/FVC, DLCO), altered left ventricular structure/function (reduced mass, size, stroke volume, cardiac output) and reduced right atrial/ventricular size. Adjustment for the combination of three sets of covariates (physical activity with BMI, lung function, cardiac structure/function) explained most of the exercise group-differences. Beyond the effects of physical activity and BMI, lung function and cardiac structure/function contributed approximately equally. BPD with other prematurity-related perinatal factors (ventilation, antenatal steroids, extremely low birth weight, extreme preterm) were not associated with a reduced exercise capacity.

CONCLUSIONS

Exercise capacity was significantly reduced in VLBW adults, which we speculate is from combined effects of impaired lung function, altered heart structure/function and reduced physical activity. Perinatal factors including BPD were not associated with a reduced exercise capacity.

Effect of Preterm Birth on Cardiac and Cardiomyocyte Growth and the Consequences of Antenatal and Postnatal Glucocorticoid Treatment

Preterm birth coincides with a key developmental window of cardiac growth and maturation, and thus has the potential to influence long-term cardiac function. Individuals born preterm have structural cardiac remodelling and altered cardiac growth and function by early adulthood. The evidence linking preterm birth and cardiovascular disease in later life is mounting. Advances in the perinatal care of preterm infants, such as glucocorticoid therapy, have improved survival rates, but at what cost? This review highlights the short-term and long-term impact of preterm birth on the structure and function of the heart and focuses on the impact of antenatal and postnatal glucocorticoid treatment on the immature preterm heart.

Cardiac Performance in the First Year of Age Among Preterm Infants Fed Maternal Breast Milk

IMPORTANCE

There is a beneficial association between human breast milk exposure in the neonatal period and cardiac mechanics in adults who were born preterm. It is unknown whether this benefit is apparent in infants in the first year of age.

OBJECTIVE

To test the hypothesis that higher consumption of mother's own milk in preterm infants is associated with enhanced cardiac performance during the first year of age.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study of cardiac and nutritional data at an academic medical center included 80 individuals born preterm and 100 individuals in the control group born full-term. All births were between 2011 and 2013. Two-dimensional echocardiograms were performed at 32 weeks' and 36 weeks' postmenstrual age and at 1 year's corrected age in individuals born preterm and at 1 month and 1 year of age in individuals born full-term. Statistical analysis was performed from January to May 2021.

EXPOSURES

Consumption of mother's own milk.

MAIN OUTCOMES AND MEASURES

Main study outcomes included echocardiography measures of right and left ventricle longitudinal strain (function), left ventricle mass index and right ventricular areas (morphology), and pulmonary vascular resistance (pulmonary hemodynamics) at age 1 year.

RESULTS

Of 180 infants included in the study, 97 (54%) were Black infants and 89 (49%) were female infants. Among the 80 infants born in the preterm cohort, 43 (54%) were female infants and 43 (54%) were Black infants. The median gestational age at birth of the preterm infants was 27.0 weeks (interquartile range, 26.0-28.0 weeks) and the median birth weight was 960 g (interquartile range, 800-1138). For each week of exposure to mother's own milk, preterm infants had greater magnitudes of right ventricular strain (eg, right longitudinal strain: β, 0.021; 95% CI, 0.002-0.041; P < .001) and left ventricular strain (eg, left longitudinal strain: β, 0.065; 95% CI, 0.049-0.080; P = .01), larger right ventricle areas (eg, systolic area: β, 0.026; 95% CI, 0.011-0.042; P = .009), larger left ventricle mass index (β, 0.045; 95% CI, 0.024-0.073; P = .003), and decreased pulmonary vascular resistance (eg, pulmonary artery acceleration time: β, 0.041; 95% CI, 0.018-0.063; P < .001) at 1 year's corrected age, even after accounting for gestational age and common neonatal morbidities. Cardiac values approached those seen in controls born full-term with increased mother's own milk exposure. There were no differences in any of the cardiac indices at 32 weeks' postmenstrual age, but with each week of exposure, right ventricle function (eg, right longitudinal strain: β, 0.016; 95% CI, 0.002-0.031; P < .001) was greater and pulmonary pressured (eg, pulmonary artery acceleration time: β, 0.0032; 95% CI, 0.0013-0.0062; P < .001).

CONCLUSIONS AND RELEVANCE

This study found that preterm infants with higher consumption of mother's own milk had enhanced cardiac performance at age 1 year, suggesting that mother's own milk consumption may play a dynamic modulator role on cardiac mechanics in preterm-born infants and help in normalization of the preterm cardiac phenotype.

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

Background

Preterm birth affects about 10% of live births worldwide and is associated with cardiac alterations. Animal models of preterm birth suggest that left ventricular functional impairment may be due to an up-regulation of myocardial fibrosis.

Objectives

The aim of this study was to determine whether diffuse left ventricular fibrosis is evident in young adults born preterm.

Methods

One hundred one normotensive young adults born preterm (n = 47, mean gestational age 32.8 ± 3.2 weeks) and term (n = 54) were included from YACHT (Young Adult Cardiovascular Health sTudy). Left ventricular structure and function were quantified by cardiovascular magnetic resonance and echocardiography. Intravenous administration of a gadolinium-based contrast agent during cardiovascular magnetic resonance was used to quantify focal myocardial fibrosis on the basis of late gadolinium enhancement and, in combination with T1 mapping, to quantify diffuse myocardial fibrosis on the basis of assessment of myocardial extracellular volume fraction.

Results

Adults born preterm had smaller left ventricular end-diastolic and stroke volumes, with greater left ventricular mass and wall thickness (P < 0.001). In addition, longitudinal peak systolic strain and diastolic strain rate by both cardiovascular magnetic resonance and echocardiography, and E/A ratio measured by echocardiography, were lower in preterm-born compared to term-born adults (P < 0.05). Extracellular volume fraction was greater in preterm-born compared with term-born adults (27.81% ± 1.69% vs 25.48% ± 1.41%; P < 0.001) and was a significant mediator in the relationship between gestational age and both longitudinal peak diastolic strain rate and E/A ratio.

Conclusions

Preterm-born young adults have greater extracellular volume fraction in the left ventricle that is inversely related with gestational age and may underlie their diastolic functional impairments.

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.

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.

The Immediate and Long-Term Impact of Preeclampsia on Offspring Vascular and Cardiac Physiology in the Preterm Infant

Hypertensive disorders of pregnancy, including preeclampsia, affect nearly 10% of all pregnancies and are associated with significant long-term detrimental effects on both maternal and offspring cardiovascular health. Current management of preeclampsia involves timely delivery with the more severe form of disease requiring iatrogenic preterm birth. The effects on the maternal cardiovascular system have been studied extensively; however, less is known about the short- and long-term impacts on offspring cardiovascular health. There is a growing body of evidence suggesting that the offspring of pre-eclamptic pregnancies have an altered cardiac structure and function, along with a unique vascular physiology driven by lower endothelial function. Many of these changes can also be seen in those born preterm even in the absence of pregnancy hypertension. It is difficult to determine the relative contribution of pre-maturity and preeclampsia to the cardiovascular phenotype of those exposed to these pregnancy complications as they are, in many cases, inextricably linked. This review, therefore, focuses specifically on the evidence from clinical studies showing a negative cardiovascular impact of preeclampsia in preterm-born offspring, investigating phenotypic similarities and differences between offspring born preterm to normotensive vs. pre-eclamptic pregnancies. We explore the unique cardiac and vascular alterations in pre-eclamptic offspring born preterm, highlighting knowledge gaps, and potential areas of further research in the field.