Normative Left Ventricular M-Mode Echocardiographic Values in Preterm Infants up to 2 kg

The Bronchopulmonary Dysplasia score: A predictive model for bronchopulmonary dysplasia or death in high-risk preterm infants

AIM

Progressive respiratory deterioration in infants at high risk of bronchopulmonary dysplasia (BPD) is associated with patent ductus arteriosus (PDA) exposure. This study aimed to design an early predictive model for BPD or death in preterm infants using early echocardiographic markers and clinical data.

METHODS

Infants born with gestational age (GA) ≤ 29 weeks and/or birth weight (BW) < 1500 g at Cork University Maternity Hospital, Ireland were retrospectively evaluated. Those with echocardiography performed between 36 h and 7 days of life were eligible for inclusion. Exclusion criteria were pulmonary hypertension and major congenital anomalies. The primary outcome was a composite of BPD and death before discharge.

RESULTS

The study included 99 infants. A predictive model for the primary outcome was developed, which included three variables (BW, Respiratory Severity Score and flow pattern across the PDA), and yielding an area under the curve of 0.98 (95% CI 0.96-1.00, p < 0.001). Higher scores were predictive of the primary outcome. A cut-off of -1.0 had positive and negative predictive values of 89% and 98%, and sensitivity and specificity of 98% and 88%, respectively.

CONCLUSION

Our prediction model is an accessible bedside tool that predicts BPD or death in premature infants.

Echocardiography in the neonatal unit: current status and future prospects

INTRODUCTION

Traditionally echocardiography was used by pediatric cardiologists to diagnose congenital heart defects in neonates. Formalized neonatal hemodynamic fellowships have been established where neonatologists acquire advanced echocardiographic skills to gain anatomical, physiological, and hemodynamic information in real time and utilize this information in making a timely and accurate physiology-based clinical decision.

AREA COVERED

Differences between a comprehensive formal structural echocardiography, neonatologist performed targeted echocardiography and limited assessment on point-of-care-ultrasonography for specific indications have been covered. This article is focused at providing a comprehensive review of the status of echocardiography in the neonatal units, recent advancements and its future prospects in the neonatal intensive care units.

EXPERT OPINION

Comprehensive guidelines providing the scope of practice, a framework for training, and robust clinical governance process for the neonatologist performed targeted echocardiography have been established. In the last decade, echocardiography has emerged as essential vital bedside diagnostic tool in providing high-quality care to the sick infants in the neonatal units, and it has proved to improve the outcomes in neonates. It is now being considered as a modern hemodynamic monitoring tool. Advances in technology, machine learning, and application of artificial intelligence in applications of echocardiography seem promising adjunct tools for rapid assessment in emergency situations.

Cardiac Hypertrophy Associated with Insulin Therapy in Extremely Preterm Infants

BACKGROUND

In the neonatal period, cardiac hypertrophy (CH) has been commonly associated with hyperinsulinemic pathologies, and the first case of CH in an extremely preterm infant treated with insulin infusion has recently been reported. To confirm this association, we report a case series of patients who developed CH after insulin therapy.

METHODS

Infants with gestational age < 30 weeks and birth weight < 1500 g, born from November 2017 to June 2022, were studied if they developed hyperglycemia requiring treatment with insulin and had echocardiographic diagnosis of CH.

RESULTS

We studied 10 extremely preterm infants (24.3 ± 1.4 weeks) who developed CH at a mean age of 124 ± 37 h of life, 98 ± 24 h after the initiation of insulin therapy. All surviving patients had resolution of CH at discharge, while three of four (75%) of the deceased patients had persistent CH.

CONCLUSIONS

Our case series supports the association between the development of CH and insulin therapy in extremely preterm infants and suggests further caution and the need for echocardiographic monitoring when treating these fragile patients with insulin.

Echocardiographic nomograms and Z-scores for term Indian neonates

Background

The availability of nomograms is crucial for the correct interpretation of pediatric and neonatal echocardiograms. Echocardiographic Z-score applications/websites use Western nomograms as reference, which may not be an appropriate standard for gauging Indian neonates. Currently available Indian pediatric nomograms either have not included neonates or have not been specifically designed for neonates. This gross underrepresentation of neonates renders available nomograms unreliable for use as standards for comparison.

Objectives

The objective of this study was to collect normative data for the measurement of various cardiac structures using M-Mode and two-dimensional (2D) echo in healthy Indian neonates and to derive Z-scores for each measured parameter.

Methods

Echocardiograms were performed on healthy term neonates (within first 5 days of life). Birth weight and length were recorded, and body surface area was calculated using Haycock's formula. Twenty M-mode and 2D-echo parameters were measured (including left ventricular dimensions, atrioventricular valves, and semilunar valves' annuli sizes, pulmonary artery and branches, aortic root, and arch).

Results

We studied 142 neonates (73 males) with a mean age of 1.83 ± 1.12 days and mean birth weight of 2.89 ± 0.39 Kg. Regression equations with linear, logarithmic, exponential and square root models were tested to select the best model of fit for the relationship between birth weight and each echocardiographic parameter. Scatter plots and nomogram charts with Z-scores were prepared for each echocardiographic parameter.

Conclusions

Our study provides nomograms with Z-scores for term Indian neonates weighing between 2 kg and 4 kg at birth, within first 5 days of life, for a set of echocardiographic parameters that are frequently used in clinical practice. This nomogram has poor predictability for babies at extremes of birth weight. There is a need for further indigenous studies to include neonates at extremes of weight, both term, and preterm.

The chance of spontaneous patent ductus arteriosus closure in preterm infants born before 32 weeks of gestation is high and continues to increase until 5 years of follow-up

AIM

The primary aim was to estimate premature infants' spontaneous patent ductus arteriosus closure rate. Secondly, to identify criteria associated with the chance of spontaneous closure.

METHODS

We performed a retrospective cohort study of 167 infants born before 32 weeks of gestation and diagnosed with a patent ductus arteriosus between 1 January 2008 and 31 December 2017. The spontaneous patent ductus arteriosus closure event rate was evaluated using the Kaplan-Meier estimator.

RESULTS

The spontaneous closure rate within the first year of life was 66% (95% CI 58%-73%), increasing to 80% (95% CI 72%-86%) five years after birth. When including both spontaneous closure and closure following treatment, 96% (95% CI 86%-100%) closed within 5 years after birth. The chance of spontaneous closure was reduced in the case of a large patent ductus arteriosus: OR 0.16 (95% CI 0.05-0.52), left atrial enlargement: OR 0.16 (95% CI 0.05-0.51), and pulmonary hypertension: OR 0.23 (95% CI 0.07-0.74).

CONCLUSION

The chance of spontaneous closure in premature infants born between 23 and 32 weeks of gestation was high, and the incidence continued increasing until 5 years of follow-up.

Percentile curves of normal echocardiographic measurements values for left heart structures in 1570 Han Chinese preterm and term infants

OBJECTIVE

This study was designed to evaluate echocardiographic measurements in Han Chinese preterm and term infants and to build percentile curves of normal echocardiographic measurements values related to the weight.

METHOD

From December 2014 to December 2021, a total of 797 male infants and 773 female infants born in * were included in the study. The echocardiographic measurements of each subject were as follows: left ventricular internal diameter at end-diastole (LVIDd), left ventricular internal diameter at end-systole (LVIDs), left ventricular posterior wall thickness at end-diastole (LVPWd), left ventricular posterior wall thickness at end-systole (LVPWs), interventricular septal thickness at end-diastole (IVSd), interventricular septal thickness at end-systole (IVSs), ascending aorta diameter (AO), left atrium (LA) dimension, left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS) and left ventricular mass (LVM). The correlations between echocardiography measurements and birth weight (BW), length (L), gestational age (GA), and body surface area (BSA) were analyzed.

RESULTS

There was a good correlation between the echocardiographic measurements and birth weight and percentile curves of the echocardiographic measurements were established according to different birth weight. The echocardiographic measurements were not affected by gender. However, LVEF and LVFS did not change with BW or gender.

CONCLUSIONS

The percentile curves of normal values make it possible to classify echocardiographic measurements for left heart structures and function as normal or abnormal and is helpful for the diagnosis of neonatal heart disease in preterm and term infants.

Reference Values for Point-of-Care Echocardiographic Measurements of Preterm Infants in China

BACKGROUND

Few studies have examined the reference value of the left ventricular structure and function in preterm infants. This study was designed to establish a point-of-care echocardiographic reference range of left ventricular structure and function based on different gestational age, weight, and body surface area (BSA) for preterm infants within 7 days after birth.

METHODS

We retrospectively studied 489 patients with traditional echocardiographic data of left ventricular (LV) M-mode: LV end diastolic dimensions (LVED), LV end systolic dimension (LVES), end-diastolic interventricular septal thickness (IVSd), end diastolic LV posterior wall thickness (LVPWd), left atrial (LA) and aortic root (AO) diameters, and index of LA/AO, LV ejection fraction (LVEF), LV fractional shortening (LVFS), and pulsed wave Doppler: aortic valve flow rate (AV), peak mitral valve flow rate E(MV-E), peak mitral valve flow rate A(MV-A), and MV-E/A. The LV dimensions and the maximum blood flow velocities of the aortic valves and mitral valves according to gestational age, birth weight, and body surface area (BSA) are presented in percentiles tables. Percentile curves of aforesaid four cardiac measurements (LVED, LA diameter (LAD), MV-E, MV-E/A) using the R language Generalized Additive Models for Location, Scale and Shape (GAMLSS) method were developed according to different gestational ages and weights.

RESULTS

Measurements of all cardiac dimensions and Doppler maximum velocities of AV, MV-E, and MV-E/A showed a correlation with gestational age, weight, and BSA. LVED, LAD, MV-E, and MV-E/A showed a trend of increasing values with gestational age and weight on the percentile curves.

CONCLUSION

The percentile tables and graphs of these point-of-care echocardiographic data can provide reliable reference data for Chinese neonates. Normative values are recommended as a source of reference data for the identification of potentially abnormal echocardiography.

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.

Cardiac remodeling during the neonatal intensive care period; a window of opportunity for early prevention of heart failure?

BACKGROUND

There is growing evidence that preterm birth is a risk factor for early heart failure as a result of cardiac remodeling during a critical period of growth and development. The aim of this study was to explore if cardiac remodeling can be detected very early after preterm birth, and if present, if those remodeling changes persist until discharge.

METHODS

Echocardiography parameters of left ventricular geometry and function were prospectively obtained with echocardiography in preterm infants <30 weeks gestation at postnatal day 3 and at 36 weeks postmenstrual age (PMA). Findings were compared to available data of healthy fetuses and cardiac remodeling was classified based on changes in left ventricular volume and/or mass.

RESULTS

65 (37 male) preterm infants were analysed. Three days after birth, 27.7% of infants had abnormal LV geometry, with immaturity and fetal growth restriction as risk factors for these early cardiac remodeling changes. At 36 weeks PMA, after a median period of 9 weeks of neonatal intensive care, 69.2% had abnormal cardiac geometry which could be classified as dilated hypertrophic remodeling (50.0%), dilated remodeling (11.5%) and hypertrophic remodeling (7.7%).

CONCLUSION

Cardiac remodeling changes can be detected very early after preterm birth. However, most changes take place during the neonatal intensive care period. The findings of this study could assist in identifying a group where an early and short-term intervention has the potential to prevent a pathway of abnormal cardiac development.

Differences in cardiac geometry in relation to body size among neonates with abnormal prenatal growth and body size at birth

OBJECTIVES

Both excessive and restricted fetal growth are associated with changes in cardiac geometry and function at birth. There are significant issues when indexing cardiac parameters for body size in the neonatal period. The aims of this study were to determine to what extent cardiac geometry is dependent on body size in term and preterm neonates with restricted or excessive fetal growth and how this is affected by adiposity.

METHODS

This was a cross-sectional study of neonates born between 31 and 42 weeks of gestation, divided into three groups: (1) small-for-gestational age (SGA, birth weight > 2 SD below the mean); (2) large-for-gestational age (LGA, birth weight > 2 SD above the mean); and (3) appropriate-for-gestational-age controls (AGA, birth weight ≤ 2 SD from the mean). Cardiac geometry and function were compared between the study groups, adjusting for body size. The potential impact of infant adiposity and maternal disease was assessed.

RESULTS

In total, 174 neonates were included, of which 39 were SGA, 45 were LGA and 90 were AGA. Body size was reflected in cardiac dimensions, with differences in cardiac dimensions disappearing between the SGA and AGA groups when indexed for body surface area (BSA) or thoracic circumference. The same was true for the differences in atrial and ventricular areas between the LGA and AGA groups. However, left ventricular inflow and outflow tract dimensions did not follow this trend as, when indexed for BSA, they were associated negatively with adiposity, resulting in diminished dimensions in LGA compared with AGA and SGA neonates. Adiposity was associated positively with left ventricular mass, right ventricular length and area and right atrial area. The SGA group showed increased right ventricular fractional area change, possibly reflecting differences in the systolic function of the right ventricle. We found evidence of altered diastolic function between the groups, with the mitral valve inflow E- to lateral E'-wave peak velocity ratio being increased in the LGA group and decreased in the SGA group.

CONCLUSIONS

Cardiac geometry is explained by body size in both term and preterm AGA and SGA infants. However, the nature of the relationship between body size and cardiac dimensions may be influenced by adiposity in LGA infants, leading to underestimation of left ventricular inflow and outflow tract dimensions when adjusted for BSA. Adjustments for thoracic circumference provide similar results to those for BSA. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Echocardiographic Assessment of Right Ventricular Afterload in Preterm Infants: Maturational Patterns of Pulmonary Artery Acceleration Time Over the First Year of Age and Implications for Pulmonary Hypertension

BACKGROUND

Assessment of pulmonary hemodynamics is critical in the diagnosis and management of cardiopulmonary disease of premature infants, but reliable noninvasive indices of pulmonary hemodynamics in preterm infants are lacking. Because pulmonary artery acceleration time (PAAT) is a validated noninvasive method to assess right ventricular (RV) afterload in infants and children, the aim of this study was to investigate the maturational changes of PAAT measures in preterm infants over the first year of age and to discern the impact of typical cardiopulmonary abnormalities on these measures.

METHODS

In a prospective multicenter study of 239 preterm infants (<29 weeks at birth), PAAT was assessed at days 1, 2, and 5 to 7, at 32 and 36 weeks' postmenstrual age, and at 1-year corrected age. To account for heart rate variability, PAAT was adjusted for RV ejection time. Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately. Intra- and interobserver reproducibility analysis was performed.

RESULTS

PAAT was feasible in 95% of the image acquisitions, and there was high intra- and interobserver agreement (intraclass correlation coefficients > 0.9 and coefficients of variation < 6%). In uncomplicated preterm infants (n = 103 [48%]) PAAT and PAAT adjusted for RV ejection time increased longitudinally from birth to 1-year corrected age (P < .001) and were linearly associated with gestational age at birth (r = 0.81 and r = 0.82, P < .001) and increasing postnatal weight and postnatal age (r > 0.81, P < .001). PAAT measures were significantly reduced (P < .001) in infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]) beyond 1 week of age.

CONCLUSIONS

PAAT measures increase in preterm infants from birth to 1-year corrected age, reflective of the physiologic postnatal drop in RV afterload. Bronchopulmonary dysplasia and pulmonary hypertension have a negative impact on PAAT measures. By demonstrating excellent reliability and establishing reference patterns of PAAT in preterm infants, this study suggests that PAAT and PAAT adjusted for RV ejection time can be used as complementary parameters to assess physiologic and pathologic changes in pulmonary hemodynamics in neonates.

Normal right and left ventricular volumes prospectively obtained from cardiovascular magnetic resonance in awake, healthy, 0- 12 year old children

INTRODUCTION

Pediatric z scores are necessary to describe size and structure of the heart in growing children, however, development of an accurate z score calculator requires robust normal datasets, which are difficult to obtain with cardiovascular magnetic resonance (CMR) in children. Motion-corrected (MOCO) cines from re-binned, reconstructed real-time cine offer a free-breathing, rapid acquisition resulting in cines with high spatial and temporal resolution. In combination with child-friendly positioning and entertainment, MOCO cine technique allows for rapid cine volumetry in patients of all ages without sedation. Thus, our aim was to prospectively enroll normal infants and children birth-12 years for creation and validation of a z score calculator describing normal right ventricular (RV) and left ventricular (LV) size.

METHODS

With IRB approval and consent/assent, 149 normal children successfully underwent a brief noncontrast CMR on a 1.5 T scanner including MOCO cines in the short axis, and RV and LV volumes were measured. 20% of scans were re-measured for interobserver variability analyses. A general linear modeling (GLM) framework was employed to identify and properly represent the relationship between CMR-based assessments and anthropometric data. Scatter plots of model fit and Akaike's information criteria (AIC) results were used to guide the choice among alternative models.

RESULTS

A total of 149 subjects aged 22 days-12 years (average 5.1 ± 3.6 years), with body surface area (BSA) range 0.21-1.63 m2 (average 0.8 ± 0.35 m2) were scanned. All ICC values were > 95%, reflecting excellent agreement between raters. The model that provided the best fit of volume measure to the data included BSA with higher order effects and gender as independent variables. Compared with earlier z score models, there is important additional growth inflection in early toddlerhood with similar z score prediction in later childhood.

CONCLUSIONS

Free-breathing, MOCO cines allow for accurate, reliable RV and LV volumetry in a wide range of infants and children while awake. Equations predicting fit between LV and RV normal values and BSA are reported herein for purposes of creating z scores.

TRIAL REGISTRATION

clinicaltrials.gov NCT02892136, Registered 7/21/2016.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Risk factors and prognostic significance of altered left ventricular geometry in preterm infants

OBJECTIVE

Left ventricular (LV) hypertrophy (LVH) predicts adverse cardiac events in adults. We sought to determine the risk factors and prognostic significance of altered LV geometry in preterm infants.

STUDY DESIGN

In an echocardiographic, single-center, retrospective case-control study we investigated the risk factors and outcomes in patients with altered LV geometry (either increased left ventricular mass index (LVMI) or increased relative wall thickness (RWT)) from a cohort of 503 preterm infants ≤2 kg.

RESULT

Altered LV geometry was seen in 180 patients and was predicted by postnatal steroids and small for gestational age. Hospital stay was longer in the elevated RWT cases. Altered LV geometry resolved in 129 of the 131 cases with follow-up echocardiogram. Fifteen of 94 patients with elevated RWT died compared to 3/90 controls (P = 0.004).

CONCLUSION

Altered LV geometry in preterm infants is associated with postnatal steroid use and small for gestational age. Elevated RWT is associated with longer hospital stay and increased mortality.

Growth of Cardiovascular Structures from the Fetus to the Young Adult

The size, hemodynamics, and function of cardiovascular structures change dramatically from the early fetal life to late adolescence. The principal determinants of cardiovascular dimensions are related to the blood flow needed to meet metabolic demands. This demand is in turn tightly related to body size and body composition, keeping in mind that various tissues may have different metabolic rates. There is no simple model that links cardiac dimensions with a single body size measurement. Consequently, despite abundant scientific literature, few studies have proposed pediatric reference values that efficiently and completely account for the effect of body size. Other factors influence cardiovascular size and function in children, including sex. The influence of sex is multifactorial and not fully understood, but differences in body size and body composition play an important role. We will first review the determinants of cardiovascular size and function in children. We then explore the evaluation and normalization of cardiovascular size and function in pediatric cardiology in relation to the growth of cardiovascular structures during childhood, with a particular focus on sex differences.