Novel Echocardiography Methods in the Functional Assessment of the Newborn Heart

Global longitudinal strain is an informative index of left ventricular performance in neonates receiving intensive care

Echocardiographic assessment of left ventricular function is crucial in NICU. The study aimed to compare the accuracy and agreement of global longitudinal strain (GLS) with conventional measurements. Real-life echocardiograms of neonates receiving intensive care were retrospectively reviewed. Shortening fraction (SF), ejection fraction (EF) and S' measurements were retrieved from health records. GLS was calculated offline from stored images. The association with stroke volume indexed for body weight (iSV) was evaluated by regression analysis. The diagnostic ability to identify uncompensated shock was assessed by ROC curve analysis. Cohen's κ was run to assess agreement. 334 echocardiograms of 155 neonates were evaluated. Mean ± SD gestational age and birth weight were 34.5 ± 4.1 weeks and 2264 ± 914 g, respectively. SF, EF, S' and GLS were associated with iSV with R2 of 0.133, 0.332, 0.252 and 0.633, (all p < .001). Including all variables in a regression model, iSV prediction showed an adjusted R2 of 0.667, (p < .001). GLS explained 73% of the model variance. GLS showed a better ability to diagnose uncompensated shock (AUC 0.956) compared to EF, S' and SF (AUC 0.757, 0.737 and 0.606, respectively). GLS showed a moderate agreement with EF (κ = .500, p < .001) and a limited agreement with S' and SF (κ = .260, p < .001, κ = .242, p < .001). GLS was a more informative index of left ventricular performance, providing the rationale for a more extensive use of GLS at the cotside.

Tissue-Tracking Mitral Annular Displacement in Neonates: A Novel Index of Left Ventricular Systolic Function

OBJECTIVES

To assess the feasibility, accuracy, and reproducibility of tissue-tracking mitral annular displacement (TMAD) compared with other measures of left ventricular systolic function in healthy preterm and term neonates in the transitional period.

METHODS

This was a prospective observational study. Two echocardiograms were performed at 24 and 48 hours of life. TMAD, shortening fraction (SF), ejection fraction (EF), s', and global longitudinal strain (GLS) were measured offline. Accuracy to detect impaired GLS was tested by ROC curve analysis. DeLong test was used to compare AUCs. Intra and interobserver reproducibility of the off-line analysis was calculated.

RESULTS

Mean ± SD gestational age and weight were 34.2 ± 3.8 weeks and 2162 ± 833 g, respectively. TMAD was feasible in 168/180 scans (93%). At 24 hours the AUC (95% CI) of SF, EF, s', and TMAD (%) was 0.51 (0.36-0.67), 0.68 (0.54-0.82), 0.63 (0.49-0.77), and 0.89 (0.79-0.99) respectively. At 48 hours the AUC (95% CI) of SF, EF, s', and TMAD (%) was 0.64 (0.51-0.77), 0.59 (0.37-0.80), 0.70 (0.54-0.86), and 0.96 (0.91-1.00), respectively. The AUC of TMAD was superior to the AUC of SF, EF, s', at both timepoints (P < .02). Intraclass correlation coefficients (95% CI) of intra and interobserver reproducibility of TMAD were 0.97 (0.95-0.99) and 0.94 (0.88-0.97), respectively.

CONCLUSION

TMAD showed improved accuracy and optimal reproducibility in neonates in the first 48 hours of life.

Shape of Pulmonary Artery Doppler Flow Profile and Right Ventricular Hemodynamics in Neonates

OBJECTIVES

To characterize pulmonary artery Doppler flow profile (PAFP) patterns among infants receiving care in neonatal intensive care units and to examine the association of PAFP patterns with pulmonary and right ventricular (RV) hemodynamics.

STUDY DESIGN

This is a retrospective study at 2 tertiary intensive care units over 4 years that included neonates who demonstrated a complete tricuspid regurgitation envelope on targeted neonatal echocardiography. Separate personnel reviewed TNEs to characterize PAFP patterns, divide cohort into PAFP groups, and measure quantitative indices of RV hemodynamics (RV systolic pressure, pulmonary artery acceleration time and its ratio with RV ejection time, tricuspid annular plane systolic excursion, and RV output), for intergroup comparisons.

RESULTS

We evaluated TNEs from 186 neonates with median gestational age of 28.5 weeks (IQR, 25.9-35.9 weeks). Four distinct PAFP patterns were identified (A) near-isosceles triangle (22%), (B) right-angled triangle (29%), (C) notching (40%), and (D) low peak velocity (<0.4 m/s; 9%). Groups A-C demonstrated a stepwise worsening in all indices of PH, whereas pattern D was associated with lower tricuspid annular plane systolic excursion and RV output. Using common definitions of pulmonary hypertension (PH), pattern A performed best to rule out PH (sensitivity range, 81%-90%) and pattern C for diagnosing PH (specificity range, 63%-78%).

CONCLUSIONS

Inspection of PAFP is a simple bedside echocardiography measure that provides clinically meaningful information on underlying RV hemodynamics and may aid in screening and monitoring of patients for PH in intensive care units.

Longitudinal Strain vs. Conventional Echocardiographic Parameters in the First Week of Life in Healthy Term Newborns

The first week of life is characterized by substantial alterations in hemodynamic conditions. Changes in myocardial contractility will reflect these changes. We aimed to assess right and left ventricular function on the third and seventh days of life in 50 healthy term newborns. To assess myocardial function, we used speckle tracking echocardiography. Pulsed-wave tissue Doppler imaging, M-mode, Doppler and pulsed-wave Doppler were also used to assess ventricular function. We found a significant increase in both right and left longitudinal strain and an increase in systolic and diastolic tissue Doppler velocities, whereas most other parameters remained unchanged. At both time points, the measured parameters were significantly greater for the right ventricle, but the changes with time were similar for both ventricles. We also found an increase in right ventricular outflow tract acceleration time as an indirect sign of decreasing pulmonary vascular resistance and an increase in systolic blood pressure, pointing to increasing systemic vascular resistance. Together with a decreasing proportion of patients with patent ductus arteriosus, the estimated left ventricular cardiac output decreased and right ventricular cardiac output increased but not to a statistically significant degree. In conclusion, the results of our study show how different echocardiographic techniques capture hemodynamic changes and changes in myocardial contractility and compliance. Both longitudinal strain and tissue Doppler imaging parameters seem to offer greater sensitivity in comparison with conventional echocardiographic parameters.

Echocardiographic Predictors of Hospital Outcomes in Preterm Neonates with Patent Ductus Arteriosus and Clinical Suspicion of Pulmonary Hypertension

Background

Preterm neonates often have an echocardiogram performed in the first few days of life for suspicion of pulmonary hypertension and patent ductus arteriosus. The usefulness of this echocardiogram in predicting outcomes in this population are unknown. The objective of this study was to investigate associations between initial echocardiographic assessment and hospital outcomes in preterm neonates with patent ductus arteriosus and clinical suspicion of pulmonary hypertension.

Methods

Premature neonates (<37 weeks gestational age) with patent ductus arteriosus and clinical suspicion of pulmonary hypertension born at our institution or transferred within 48 hours of life were included in this single center retrospective study. The primary outcome was in-hospital extracorporeal membrane oxygenation utilization or mortality.

Results

86 patients were included. Median age at echocardiogram was 2 days (interquartile range 1,7), gestational age was 27 weeks (interquartile range 25,32), and birth weight was 878 grams (interquartile range 650,1818). 15 patients (17%) met the primary outcome. Larger patent ductus arteriosus size (p = .03), patent foramen ovale flow that was bidirectional or right to left (p = .047), and right atrial volume (p = .04) were independently associated with the primary outcome.

Conclusion

Larger patent ductus arteriosus size, bidirectional or right to left flow at the patent foramen ovale, and lower right atrial volume are independently associated with in-hospital mortality. These findings on the initial echocardiogram of a preterm neonate can be used to risk stratify these patients for elevated risk for in-hospital extracorporeal membrane oxygenation utilization or mortality.

Atrial Septal Defect: Larger Right Ventricular Dimensions and Atrial Volumes as Early as in the First Month After Birth-a Case-Control Study Including 716 Neonates

Atrial septal defect (ASD) is characterized by a left-to-right shunt causing dilatation of the right atrium and right ventricle as well as pulmonary hyperperfusion. The detection of ASDs often occurs late in childhood or adulthood. Little is known about cardiac structure and function in neonates with ASD.We analyzed neonatal echocardiograms from the Copenhagen Baby Heart Study, a multicenter, population-based cohort study of 27,595 neonates. We included 716 neonates with secundum-type ASDs and matched them 1:1 on sex and age at examination with neonates without ASD from the same birth cohort. Neonates with an ASD (median age 11 days, 52% female) had larger right ventricular (RV) dimensions than matched controls (RV longitudinal dimension end-diastole: 27.7 mm vs. 26.7 mm, p < 0.001; RV basal dimension end-diastole: 14.9 mm vs. 13.8 mm, p < 0.001; and RV outflow tract diameter 13.6 mm vs. 12.4 mm, p < 0.001). Atrial volumes were larger in neonates with ASD compared to controls (right atrial end-systolic volume: 2.9 ml vs. 2.1 ml, p < 0.001; and left atrial end-systolic volume 2.0 ml vs. 1.8 ml, p < 0.001). Tricuspid annular plane systolic excursion was larger in neonates with ASD than in controls (10.2 mm vs. 9.6 mm, p < 0.001). Left ventricular dimensions and function did not differ between neonates with ASD and controls. In conclusion, ASDs were associated with altered cardiac dimensions already in the neonatal period, with larger right ventricular dimensions and larger atrial volumes at echocardiography within the first 30 days after birth.ClinicalTrials.gov Identifier: NCT02753348 (April 27, 2016).

Assessment and management of neonates with unrepaired congenital heart disease

PURPOSE OF REVIEW

To review preoperative assessment and management of neonates with congenital heart disease (CHD).

RECENT FINDINGS

The spectrum for neonates with CHD can be wide and complex. An in-depth understanding of their physiology is the first step in assessing their hemodynamics and developing an effective therapeutic strategy.

SUMMARY

There is significant heterogeneity in the anatomy and physiology in newborns with CHD. Their complex pathophysiology can be simplified into seven basic subtypes, which include systolic dysfunction, diastolic dysfunction, excessive pulmonary blood flow, obstructed pulmonary blood flow, obstructed systemic blood flow, transposition physiology, and single ventricle physiology. It is important to note these physiologies are not mutually exclusive, and this review summarizes the hemodynamic and therapeutic strategies available for the preoperative neonate with CHD.

A Comprehensive Echocardiographic Assessment of Neonatal Right Ventricular Function in Neonatal Intensive Care Unit Babies

Background The right ventricle (RV) in the fetus is the predominant chamber, accounting for about 60% of the total cardiac output. The majority of the RV outflow volume is diverted from the pulmonary artery via the ductus arteriosus to the descending aorta. After birth, the RV undergoes extensive structural and functional modifications. The RV undergoes an improper transition from fetal to neonatal circulation in sick neonatal intensive care unit (NICU) babies. Functional echocardiography is now commonly being used in most NICUs as it is a noninvasive and bedside investigation that gives an immediate evaluation of hemodynamics and can be taken into consideration as an extension of clinical assessment to study a critically unwell neonate. Therefore, a study of RV functions in NICU neonates will help in better understanding the neonatal cardiopulmonary response to different diseases. Thus, this study aimed to assess RV functions in neonates getting admitted to the NICU of a tertiary care institute. Methodology This observational, cross-sectional study was approved by the Research & Recognition Committee of Dr. D. Y. Patil Vidyapeeth, Pune. In total, 35 cases of term neonates admitted to the NICU at Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune who fulfilled the inclusion criteria were enrolled in this study after obtaining consent from their parents. Two-dimensional echocardiography was performed by a trained pediatric cardiologist, and the findings were substantiated by a neonatologist trained in echocardiography. Results Our study found a strong association between tricuspid inflow velocity and neonates with sepsis. Similarly, a significant association was observed between abnormal tricuspid Inflow velocity (E/A and E/E') and neonates requiring inotropic support. Conclusions Data on the normal values of different echocardiographic parameters of the systolic and diastolic function of the RV during the neonatal phase of life are currently limited. Our data offer preliminary insights into this topic. Early echocardiography and intervention are advisable, especially in neonates with sepsis and requiring inotropic support.

Umbilical cord serum insulin-like growth factor-1 levels of infants of diabetic mothers are correlated with diastolic dysfunction detected by tissue Doppler echocardiography

Tissue Doppler echocardiography (TDI) is a convenient method to detect cardiac dysfunction in the infants of diabetic mothers (IDMs). Umbilical cord serum insulin-like growth factor-1 (IGF-1) is known to be higher in IDMs. We aimed to determine whether there is a relation between diastolic functions examined by TDI and cord serum IGF-1 levels of IDMs. Cord serum IGF-1 levels of 32 IDMs and 22 healthy infants were measured. The cardiac functions of the infants were evaluated by M-Mode and TDI. For statistical analysis, Mann-Whitney U and Spearman correlation tests were used for continuous variables, and the chi-square test was used for categorical variables. The cord serum IGF-1 levels of the IDMs were higher (p = 0.000). The left ventricle (LV) e', LVa', LV e'/a', and LV Tei index, indicating left ventricular diastolic dysfunction in IDMs, were detected (LV e' p = 0.016; LV a' p = 0.003; LV e'/ a' p = 0.000; LV Tei index p = 0.023). IDMs' cord serum IGF-1 levels were found weakly correlated with the interventricular septum (IVS) and left ventricle posterior wall (LVPW) thicknesses in M-Mode and LV e' and LV e'/a' in TDI (IVS r = 0.357, p = 0.008; LVPW r = 0.289, p = 0.034; LV e' r = 0.297, p = 0.029; LV e'/ a' r = 0.031, p = 0.014).

CONCLUSION

To our knowledge, this is the first study to examine the relationship between cord serum IGF-1 levels and diastolic functions of IDMs assessed by TDI. A weak correlation was found between IGF-1 levels and IVS and LVPW thicknesses in M-Mode and LV e' and LV e'/a' parameters in TDI, revealing diastolic dysfunction in IDMs.

WHAT IS KNOWN

• The umbilical cord blood serum IGF-1 level of IDMs is higher than in infants of healthy mothers. • Diastolic dysfunction is a well-studied and frequently observed consequence in IDMs.

WHAT IS NEW

• This is the first study to examine the relationship between cord serum IGF-1 levels and diastolic functions of IDMs assessed by TDI. • A weak correlation was detected between the median cord serum IGF-1 level of IDMs and the median values of IVS, LVPW, LV e', LV a', LV e'/a' ratio.

Targeted Neonatal Echocardiography in Patients With Hemodynamic Instability

Targeted neonatal echocardiography (TNE) has been increasingly used at the bedside in neonatal care to provide an enhanced understanding of physiology, affecting management in hemodynamically unstable patients. Traditional methods of bedside assessment, including blood pressure, heart rate monitoring, and capillary refill are unable to provide a complete picture of tissue perfusion and oxygenation. TNE allows for precision medicine, providing a tool for identifying pathophysiology and to continually reassess rapid changes in hemodynamics. A relationship with cardiology is integral both in training as well as quality assurance. It is imperative that congenital heart disease is ruled out when utilizing TNE for hemodynamic management, as pathophysiology varies substantially in the assessment and management of patients with congenital heart disease. Utilizing TNE for longitudinal hemodynamic assessment requires extensive training. As the field continues to grow, guidelines and protocols for training and indications are essential for ensuring optimal use and providing a platform for quality assurance.

Comprehensive assessment of biventricular myocardial function by two-dimensional speckle tracking echocardiography in infants of gestational diabetic mothers

AIMS

No previous research provided a complete biventricular and multidirectional left ventricular (LV) functional assessment by two-dimensional (2D) speckle tracking echocardiography (STE) in infants of gestational diabetic mothers (IGDM) METHODS: A total of 30 consecutive IGDM and 30 infants of healthy mothers were examined between March 2021 and July 2021. Both groups of infants underwent evaluation by neonatologist and 2D transthoracic echocardiography (TTE) implemented with 2D-STE quantification of LV-global longitudinal strain (GLS), LV-global circumferential strain (GCS), LV-global radial strain (GRS) and right ventricular (RV)-GLS, within 3 days of life and at 40 days after birth. Predictors of persistent subclinical myocardial dysfunction, defined as a LVGLS less negative than -20% at 40-day follow-up, in IGDM population, were determined.

RESULTS

At 2.2 ± 1.3 days after birth, LV-GLS (- 17.2 ± 1.9 vs. - 23.9 ± 3.8%), LV-GCS (- 17.9 ± 2.7 vs. - 27.3 ± 3.4%), LV-GRS (25.6 ± 3.4 vs. 35.8 ± 3.6%) and RV-GLS (- 17.6 ± 3.6 vs. - 22.6 ± 3.8%) were significantly impaired in IGDM than controls (all p < 0.001). At 36.8 ± 5.2 days of life, LV-GLS was still impaired (less negative than -20%) in 26.6% of IGDM. Maternal third trimester body mass index (BMI) (OR 1.89, 95%CI 1.05-3.39) and third trimester glycosylated hemoglobin (HbA1C) (OR 1.59, 95%CI 1.08-2.19) were independently associated with persistent LV-GLS impairment in IGDM. Maternal BMI ≥ 30 Kg/m2 and HbA1C ≥ 38 mmol/mol showed the maximum of sensitivity and specificity for predicting persistent subclinical myocardial dysfunction in IGDM at 40 days of life.

CONCLUSIONS

IGDM have diffuse pattern of myocardial dysfunction during perinatal period. This dysfunction may be persistent up to 40 days of life in infants of GDM women with obesity and uncontrolled diabetes.

Diagnosis and management of pulmonary hypertension in infants with bronchopulmonary dysplasia

Chronic pulmonary hypertension of infancy (cPHi) is a heterogeneous disease process that contributes to morbidity and mortality in preterm infants. cPHi is most commonly associated with chronic lung disease of prematurity and represents a unique phenotype of bronchopulmonary dysplasia. It is characterized by persistently elevated or newly rising pulmonary vascular resistance and pulmonary artery pressure beyond the first weeks of age. The high-pressure afterload on the right ventricle may or may not be tolerated, depending upon additional cardiovascular shunting and co-morbidities. A comprehensive clinical evaluation combined with advanced hemodynamic assessment by echocardiography and other cardiac imaging modalities help decipher the etiopathologies of disease, identify cardiopulmonary compromise earlier and guide individualized therapeutic intervention tailored by the phenotype. This review summarizes the underlying etiologies, risk factors for development, hemodynamic assessment, management, and follow-up of cPHi in preterm infants. We offer an algorithm for early detection of cPHi and outline research priorities.

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.

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

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

Effect of Temporal and Spatial Smoothing on Speckle-Tracking-Derived Strain in Neonates

Clinical application of strain in neonates requires an understanding of which image acquisition and processing parameters affect strain values. Previous studies have examined frame rate, transmitting frequency, and vendor heterogeneity. However, there is a lack of human studies on how user-regulated spatial and temporal smoothing affect strain values in 36 neonates. This study examined nine different combinations of spatial and temporal smoothing on peak systolic left ventricular longitudinal strain in 36 healthy neonates. Strain values were acquired from four-chamber echocardiographic images in the software-defined epicardial, midwall, and endocardial layers in the six standard segments and average four-chamber stain. Strain values were compared using repeated measure ANOVAs. Overall, spatial smoothing had a larger impact than temporal smoothing, and segmental strain values were more sensitive to smoothing settings than average four-chamber strain. Apicoseptal strain decreased by approximately 4% with increasing spatial smoothing, corresponding to a 13-19% proportional change (depending on wall layer). Therefore, we recommend clinicians be mindful of smoothing settings when assessing segmental strain values.

Pulmonary hypertension and myocardial function in infants and children with Down syndrome

Down Syndrome (DS) is the most common chromosomal abnormality of live born babies. Individuals with DS are at increased risk of cardiopulmonary morbidities in the early neonatal period, infancy and childhood that manifest with elevated pulmonary arterial pressures and altered myocardial performance. Pulmonary hypertension (PH) during the early neonatal period remains under-recognised in this population. PH may occur with or without a congenital heart defect in children with DS and is more common than in the general population. Early detection and continued screening of PH throughout infancy and childhood for these at-risk children is crucial for prompt intervention and potential prevention of long-term sequelae on cardiac function. This review summarises the main physiological concepts behind the mechanisms of PH in children with DS and provides a summary of the current available literature on PH and its impact on myocardial performance.

Longitudinal assessment of cardiac function in infants with Down's syndrome using novel echocardiography techniques - project protocol

Background: Down’s syndrome (DS) is the most common chromosomal abnormality globally. Ireland has one of the highest rates of DS in the western world with an incidence of 1:444 live births. Congenital heart disease (CHD) and pulmonary hypertension (PH) are the commonest morbidities affecting the cardiovascular system in DS. PH is associated with significant morbidity and an increase risk of mortality. The impact of the diagnosis of DS, the presence of CHD and the associated PH on myocardial function during transition and over the first 2 years of age in this population is not well defined and warrants further study. In particular, serial measurements of pulmonary pressures in this population over the first week of age are lacking. This study aims to characterise myocardial function and pulmonary haemodynamics in infants with Down syndrome during the transitional period (over the first week of age) and throughout the first two years of age.

Methods: A prospective, observational study utilising novel echocardiography techniques to assess myocardial function and pulmonary haemodynamics over the first two years of age in infants with Down Syndrome. A population of healthy infants without CHD or a diagnosis of DS will be recruited as controls. This study will be conducted across the three Dublin maternity units.

Discussion: In total, 70 babies with DS have been enrolled into this study with 292 echocardiograms performed to date. Further evaluation of cardiac performance in DS infants with and without CHD may yield more insight into the pathophysiology of cardiac dysfunction and pulmonary hypertension that are recognised features in these patients. This could aid in our ability to monitor and treat patients, as well as improve our ability to predict outcomes.

Updates on Management for Acute and Chronic Phenotypes of Neonatal Pulmonary Hypertension

Neonatal pulmonary hypertension is a heterogeneous disease in term and preterm neonates. It is characterized by persistent increase of pulmonary artery pressures after birth (acute) or an increase in pulmonary artery pressures after approximately 4 weeks of age (chronic); both phenotypes result in exposure of the right ventricle to sustained high afterload. In-depth clinical assessment plus echocardiographic measures evaluating pulmonary blood flow, pulmonary vascular resistance, pulmonary capillary wedge pressure, and myocardial contractility are needed to determine the cause and provide individualized targeted therapies. This article summarizes the causes, risk factors, hemodynamic assessment, and management of neonatal pulmonary hypertension.

Maturational patterns of left ventricular rotational mechanics in pre-term infants through 1 year of age

BACKGROUND

Pre-mature birth impacts left ventricular development, predisposing this population to long-term cardiovascular risk. The aims of this study were to investigate maturational changes in rotational properties from the neonatal period through 1 year of age and to discern the impact of cardiopulmonary complications of pre-maturity on these measures.

METHODS

Pre-term infants (<29 weeks at birth, n = 117) were prospectively enrolled and followed to 1-year corrected age. Left ventricular basal and apical rotation, twist, and torsion were measured by two-dimensional speckle-tracking echocardiography and analysed at 32 and 36 weeks post-menstrual age and 1-year corrected age. A mixed random effects model with repeated measures analysis was used to compare rotational mechanics over time. Torsion was compared in infants with and without complications of cardiopulmonary diseases of pre-maturity, specifically bronchopulmonary dysplasia, pulmonary hypertension, and patent ductus arteriosus.

RESULTS

Torsion decreased from 32 weeks post-menstrual age to 1-year corrected age in all pre-term infants (p < 0.001). The decline from 32 to 36 weeks post-menstrual age was more pronounced in infants with cardiopulmonary complications, but was similar to healthy pre-term infants from 36 weeks post-menstrual age to 1-year corrected age. The decline was due to directional and magnitude changes in apical rotation over time (p < 0.05).

CONCLUSION

This study tracks maturational patterns of rotational mechanics in pre-term infants and reveals torsion declines from the neonatal period through 1 year. Cardiopulmonary diseases of pre-maturity may negatively impact rotational mechanics during the neonatal period, but the myocardium recovers by 1-year corrected age.

Intervention and Outcome for Neonatal Hypotension

Many observational studies have shown that infants with blood pressures (BPs) that are in the lower range for their gestational age tend to have increased complications such as an increased rate of significant intraventricular hemorrhage and adverse long-term outcome. This relationship does not prove causation nor should it create an indication for treatment. However, many continue to intervene with medication for low BP on the assumption that an increase in BP will result in improved outcome. Only adequately powered prospective randomized controlled trials can answer the question of whether individual treatments of low BP are beneficial.

The Future of Cardiac Ultrasound in the Neonatal Intensive Care Unit

Cardiac ultrasound is increasingly used to guide hemodynamic decision making in the neonatal intensive care unit (NICU). This article focuses on likely future progress in training, accreditation, digital connectivity, miniaturization, and modality development. Many documents have been published internationally to guide cardiac ultrasound training, accreditation, and implementation in the NICU, but challenges remain in providing assessments of hemodynamic status without risking missed structural diagnoses. Advances in simulation training and digital connectivity provide an opportunity to standardize approaches across institutions and continents. Development of machine learning and ultrasound modalities in turn provide huge scope for improving robustness and completeness of assessment.

Tripartite Assessment of Right Ventricular Systolic Function in Persistent Pulmonary Hypertension of the Newborn

Non-invasive evaluation of right ventricular (RV) systolic function in neonates with pulmonary hypertension (PH) with traditional metrics including RV fractional area change (FAC) and tricuspid annular systolic plane excursion (TAPSE) has improved outcomes. Apical three-chamber (3C) RV-FAC, a novel tripartite assessment of the RV, has recently been described in healthy infants. We assess the utility of 3C RV-FAC and biplane RV-FAC in delayed transitioning and neonatal PH. Echocardiograms for 22 normal infants and 22 infants with PH were retrospectively analyzed for RV systolic function indices including four chamber (4C), 3C, and biplane RV-FAC, TAPSE, Tei index, and RV systolic excursion velocity (S'). 4C, 3C, and biplane RV-FAC correlated with PH severity and was decreased in neonates with PH compared to normal neonates (biplane RV-FAC 31.7 ± 13.4% vs. 41 .9 ± 4.7%, p = 0.002). TAPSE was significantly decreased in neonates with PH, but did not correlate with PH severity. Other RV systolic function metrics were not significantly different between normal neonates and neonates with PH. 3C RV-FAC and biplane RV-FAC are lower in neonates with PH. 3C and biplane RV-FAC may allow for improved assessment of global RV systolic dysfunction in newborns with delayed transitioning or PH compared to the commonly used regional methods.

Reference ranges for the fetal mitral, tricuspid, and interventricular septum annular plane systolic excursions (mitral annular plane systolic excursion, tricuspid annular plane systolic excursion, and septum annular plane systolic excursion) between 20 and 36 + 6 weeks of gestation

Objectives This study aimed to establish reference ranges for fetal mitral, tricuspid, and interventricular septum annular plane systolic excursions (MAPSE, TAPSE, and SAPSE) in normal pregnant women between 20 and 36 + 6 weeks of gestation. Methods This prospective and cross-sectional study included 360 low-risk singleton pregnancies between 20 and 36 + 6 weeks of gestation. MAPSE, TAPSE, and SAPSE were measured by M-mode in real time in an apical or basal four-chamber view through placing the cursor at the atrioventricular junction, marked by the valve rings at the tricuspid, mitral, and basal septum, respectively. A regression analysis was done to determine the appropriate polynomial equation model for both measurements and standard deviation (SD) values in relation to gestational age (GA). The intra- and inter-observer reproducibility was evaluated using the concordance correlation coefficient (CCC) and limits of agreement (LoA). Results There was a significant positive correlation between MAPSE (r=0.705, p<0.0001), TAPSE (r=0.804, p<0.0001), and SAPSE (r=0.690, p<0.0001) and GA. The mean of each parameter ranged as follows: 2.87-5.56 mm, MAPSE; 3.98-8.07 mm, TAPSE; and 2.34-4.21 mm, SAPSE. Poor/moderate intra- and inter-observer reliability (CCC between 0.70 and 0.90) and poor/moderate agreement of all the tested parameters were evaluated (LoA between 10 and 50%). Conclusions Reference values were established for the fetal MAPSE, TAPSE, and SAPSE between 20 and 36 + 6 weeks of gestation in low-risk pregnant women. These parameters showed poor/moderate reproducibility.

Neonatal functional echocardiography

PURPOSE OF REVIEW

The role of echocardiography has dramatically changed over the past decade and use of functional echocardiography has become increasingly popular among neonatologists and pediatric intensivists in making clinical decisions in sick infants and children. The purpose of this review is to outline the current capabilities and limitations of functional echocardiography, best practices for its clinical application, and evidence for its utility.

RECENT FINDINGS

Functional echocardiography can provide direct assessment of hemodynamics at bedside and can be used as a modern hemodynamic monitoring tool in the neonatal intensive care unit. It is now being regarded as a useful extension to the clinical examination and other monitoring tools in the critically ill infant. The anatomic, physiological, and hemodynamic information functional echocardiography provides can be used in targeting specific interventions and evaluating response to treatment.

SUMMARY

This review article is focused on an overview of the most common applications of functional neonatal echocardiography also called targeted neonatal echocardiography or neonatologist performed echocardiography. It will review assessment of hemodynamics and cardiac function in neonatal hypotension and shock, suspected patent ductus arteriosus, suspected persistent pulmonary hypertension of the newborn with evaluation of pulmonary artery pressure and assessment of pericardial effusion. It will also emphasize the specific requirements for the practice and training of functional neonatal echocardiography.

Myocardial function in late preterm infants during the transitional period: comprehensive appraisal with deformation mechanics and non-invasive cardiac output monitoring

BACKGROUND

There is a paucity of functional data on mid-to-late preterm infants between 30+0 and 34+6 weeks gestation. We aimed to characterise transitional cardiopulmonary and haemodynamic changes during the first 48 hours in asymptomatic mid-to-late preterm infants.

METHODS

Forty-five healthy preterm newborns (mean ± standard deviation) gestation of 32.7 ± 1.2 weeks) underwent echocardiography on Days 1 and 2. Ventricular mechanics were assessed by speckle tracking-derived deformation, rotational mechanics, tissue Doppler imaging, and right ventricle-focused measures (tricuspid annular plane systolic excursion, fractional area change). Continuous haemodynamics were assessed using the NICOM™ system to obtain left ventricular output, stroke volume, heart rate, and total peripheral resistance by non-invasive cardiac output monitoring.

RESULTS

Right ventricular function increased (all measures p < 0.005) with mostly stable left ventricular performance between Day 1 and Day 2. NICOM-derived left ventricular output [mean 34%, 95% confidence interval 21-47%] and stroke volume [29%, 16-42%] increased with no change in heart rate [5%, -2 to 12%]. There was a rise in mean blood pressure [11%, 1-21%], but a decline in total peripheral resistance [-14%, -25 to -3%].

CONCLUSION

Left ventricular mechanics remained persevered in mid-to-late premature infants, but right ventricular function increased. Non-invasive cardiac output monitoring is feasible in preterm infants with an increase in left ventricular output driven by an improvement in stroke volume during the transitional period.

What is Left Ventricular Strain in Healthy Neonates? A Systematic Review and Meta-analysis

Reference values for left ventricular systolic strain in healthy neonates are necessary for clinical application of strain. The objectives of this systematic review were to identify echocardiographic studies that presented left ventricular strain values in healthy neonates, perform a meta-analysis for speckle tracking-derived global longitudinal strain, and identify areas that require further investigation. A structured search was applied to MEDLINE, Embase, and Cochrane Central Register of Clinical Trials in search of echocardiographic studies that presented left ventricular strain in healthy neonates. 244 studies were identified, of which 16 studies including speckle tracking and tissue Doppler strain in the longitudinal, radial, and circumferential directions passed the screening process. Out of these 16 studies, a meta-analysis was performed on the 10 studies that reported speckle tracking global longitudinal strain. Mean speckle tracking-derived global longitudinal strain was 21.0% (95% Confidence Interval 19.6-22.5%, strain given as positive values). When the studies were divided into subgroups, mean speckle tracking global longitudinal strain from the four-chamber view was 19.5% (95% Confidence Interval 18.0-21.0%) and that derived from all three apical views was 22.5% (95% CI 20.6-24.7%), indicating that global longitudinal strain from the four-chamber view is slightly lower than global longitudinal strain from all three apical views. Neonatal strain values were close to strain values in older subjects found in previous meta-analyses. Further studies are recommended that examine strain rate, segmental strain values, strain derived from short axis views, and strain in the first few hours after birth.

Pulmonary Hypertension Associated with Bronchopulmonary Dysplasia: A Review

Early pulmonary vascular disease (PVD) and established pulmonary hypertension (PH) are common associations of bronchopulmonary dysplasia (BPD). Diagnosis of PH is often made by echocardiography because of technical and logistic difficulties with the neonatal population. Optimization of respiratory support is the focus of treatment, however, medical therapies are being used with increased frequency. The prognosis for PH associated with BPD (PH-BPD) is tied to the child's respiratory status. PH is associated with increased risk of death in this population, so active screening and treatment is recommended to minimize morbidity and mortality. In this review, we discuss the pathophysiology of PH in infants with BPD, evaluate the current understanding of screening, diagnosis, and follow-up evaluation; describe comorbid conditions; and provide a framework for targeted physiology-based management strategies.

Tissue damage in the heart after cardiac arrest induced by asphyxia and hemorrhage in newborn pigs

BACKGROUND

Asphyxia of newborns is a severe and frequent challenge of the peri- and postnatal period.

METHODS

Forty-four neonatal piglets underwent asphyxia and hemorrhage (AH), followed by resuscitation with blood or crystalloid transfusion. In this study, 15 piglets (blood n = 9, NaCl n = 6, mean age 31 h) were randomly chosen. Four hours after return of spontaneous circulation, heart tissue and blood were collected. Analyses of heart fatty acid binding protein (HFABP), cardiac troponin I (TnI) levels, and activation of the complement system were performed. Histological staining for connexin 43 (Cx43) and complement C5a receptor 1 (C5aR1) was performed.

RESULTS

Following AH, systemic elevation of cardiac TnI and HFABP revealed cardiac damage in both groups. Systemic activation of the complement system and the appearance of extracellular histones in plasma of the blood transfusion group were observed. The Cx43 was translocated from the intercalated discs to the cytosol after AH. Cardiac glycogen concentration was reduced in both groups. A significant reduction of C5aR1 in the left ventricle and a significant elevation of the heart injury score were investigated after blood transfusion.

CONCLUSION

AH leads to alteration of the heart, particularly in Cx43 and glycogen reserves, as well as local inflammation.

Early prediction of spontaneous Patent Ductus Arteriosus (PDA) closure and PDA-associated outcomes: a prospective cohort investigation

BACKGROUND

Patent ductus arteriosus (PDA), the most commonly diagnosed cardiovascular condition in preterm infants, is associated with increased mortality and harmful long-term outcomes (chronic lung disease, neurodevelopmental delay). Although pharmacologic and/or interventional treatments to close PDA likely benefit some infants, widespread routine treatment of all preterm infants with PDA may not improve outcomes. Most PDAs close spontaneously by 44-weeks postmenstrual age; treatment is increasingly controversial, varying markedly between institutions and providers. Because treatment detriments may outweigh benefits, especially in infants destined for early, spontaneous PDA closure, the relevant unanswered clinical question is not whether to treat all preterm infants with PDA, but whom to treat (and when). Clinicians cannot currently predict in the first month which infants are at highest risk for persistent PDA, nor which combination of clinical risk factors, echocardiographic measurements, and biomarkers best predict PDA-associated harm.

METHODS

Prospective cohort of untreated infants with PDA (n=450) will be used to predict spontaneous ductal closure timing. Clinical measures, serum (brain natriuretic peptide, N-terminal pro-brain natriuretic peptide) and urine (neutrophil gelatinase-associated lipocalin, heart-type fatty acid-binding protein) biomarkers, and echocardiographic variables collected during each of first 4 postnatal weeks will be analyzed to identify those associated with long-term impairment. Myocardial deformation imaging and tissue Doppler imaging, innovative echocardiographic techniques, will facilitate quantitative evaluation of myocardial performance. Aim1 will estimate probability of spontaneous PDA closure and predict timing of ductal closure using echocardiographic, biomarker, and clinical predictors. Aim2 will specify which echocardiographic predictors and biomarkers are associated with mortality and respiratory illness severity at 36-weeks postmenstrual age. Aim3 will identify which echocardiographic predictors and biomarkers are associated with 22 to 26-month neurodevelopmental delay. Models will be validated in a separate cohort of infants (n=225) enrolled subsequent to primary study cohort.

DISCUSSION

The current study will make significant contributions to scientific knowledge and effective PDA management. Study results will reduce unnecessary and harmful overtreatment of infants with a high probability of early spontaneous PDA closure and facilitate development of outcomes-focused trials to examine effectiveness of PDA closure in "high-risk" infants most likely to receive benefit.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03782610. Registered 20 December 2018.

NT-proBNP as an Early Marker of Diastolic Ventricular Dysfunction in Very-Low-Birth-Weight Infants

The objective is to examine the correlation between plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and tissue Doppler imaging (TDI) echocardiographic parameters in the first 28 days of life in very-low-birth-weight infants (VLBWI). VLBWI admitted to the Neonatal Intensive Care Unit (NICU) at Hospital Puerta del Mar, Spain, from January 2015 to January 2017 were prospectively enrolled. Weekly determination of plasma NT-proBNP (pg/mL), and echocardiograms were done during the first 28 days of life. 101 preterm infants with a mean GA of 28.85 weeks (± 1.85 SD) and mean birth weight of 1152 g (± 247.4 SD) were included. A total of 483 echocardiograms and 139 NT-proBNP determinations were performed. We found a negative correlation between plasma NT-proBNP levels and diastolic velocities: mitral A' (ρ = - 0.15, p = 0.04), mitral E' (ρ = - 0.17, p = 0.02), tricuspid A' (ρ = - 0.20, p = 0.006), tricuspid E' (ρ = - 0.24, p = 0.0009). In the first 24 h of life, NT-proBNP levels were strongly correlated with mitral A' and E' velocities in patients with no patent ductus arteriosus (PDA) (ρ = - 0.75, p = 0.04). In preterm patients, elevated NT-proBNP levels are related to worse diastolic myocardial function. In the first 24 h, this correlation is much stronger in the absence of PDA.

Persistence of right ventricular dysfunction and altered morphometry in asymptomatic preterm Infants through one year of age: Cardiac phenotype of prematurity

INTRODUCTION

Prematurity impacts myocardial development and may determine long-term outcomes. The objective of this study was to test the hypothesis that preterm neonates develop right ventricle dysfunction and adaptive remodelling by 32 weeks post-menstrual age that persists through 1 year corrected age.

MATERIALS AND METHODS

A subset of 80 preterm infants (born <29 weeks) was selected retrospectively from a prospectively enrolled cohort and measures of right ventricle systolic function and morphology by two-dimensional echocardiography were assessed at 32 weeks post-menstrual age and at 1 year of corrected age. Comparisons were made to 50 term infants at 1 month and 1 year of age. Sub-analyses were performed in preterm-born infants with bronchopulmonary dysplasia and/or pulmonary hypertension.

RESULT

In both term and preterm infants, right ventricle function and morphology increased over the first year (p < 0.01). The magnitudes of right ventricle function measures were lower in preterm-born infants at each time period (p < 0.01 for all) and right ventricle morphology indices were wider in all preterm infants by 1 year corrected age, irrespective of lung disease. Measures of a) right ventricle function were further decreased and b) morphology increased through 1 year in preterm infants with bronchopulmonary dysplasia and/or pulmonary hypertension (p < 0.01).

CONCLUSION

Preterm infants exhibit abnormal right ventricle performance with remodelling at 32 weeks post-menstrual age that persists through 1 year corrected age, suggesting a less developed intrinsic myocardial function response following preterm birth. The development of bronchopulmonary dysplasia and pulmonary hypertension leave a further negative impact on right ventricle mechanics over the first year of age.

Cardiac mechanics in infants with Down syndrome in the early neonatal period

OBJECTIVE

The objective of this study is to test whether myocardial performance is impaired over the first week of age in infants with Down syndrome (DS) without congenital heart disease (CHD).

STUDY DESIGN

A prospective cohort study of 20 infants with DS without CHD and 17 healthy term infants comparing echocardiographic measures of left (LV) and right (RV) ventricular function and pulmonary hypertension (PH) on days 1, 2, and 5-7.

RESULTS

Indices of PH were higher in the DS group over the study period. Infants with DS had larger RV and smaller LV dimensions. Fractional area change and RV longitudinal strain values were lower in the DS group. LV shear strain values were lower in infants with DS driven by a lack of basal rotation.

CONCLUSION

Infants with DS without CHD and echocardiographic evidence of PH during the early neonatal period demonstrate reduced RV systolic function with impaired LV rotational mechanics, reflective of the ventricular interdependence.

Future perspectives on the use of deformation analysis to identify the underlying pathophysiological basis for cardiovascular compromise in neonates

The assessment of the wellbeing of the cardiovascular status in premature infants has come to the forefront in recent years. There is an increasing realisation that myocardial performance, systemic blood flow and end-organ perfusion (particularly during the transitional period) play an important role in determining short and long-term outcomes in this population. The recent open access series on Neonatologist Performed Echocardiography (NPE) published in this journal outline the necessary techniques for image acquisition and analysis and provide a framework for the potential clinical applications of NPE in neonatal, and specifically preterm care. In this "Future Perspectives" review, we describe the important determinants of adequate cellular metabolism and myocardial performance (e.g. loading conditions, intrinsic contractility and morphological change), we discuss the maladaptive state of the preterm cardiovascular system, and highlight the emerging role that non-invasive echocardiography techniques, such as deformation analysis, serve in identifying the underlying physiological basis for cardiovascular instability.

Postnatal Myocardial Function in Monochorionic Diamniotic Twins with Twin-to-Twin Transfusion Syndrome following Selective Laser Photocoagulation of the Communicating Placental Vessels

BACKGROUND

Monochorionic diamniotic (MCDA) twins are at risk for developing twin-to-twin transfusion syndrome (TTTS) throughout pregnancy. This may lead to myocardial dysfunction in the recipient and/or donor twin that persists beyond delivery. Selective laser photocoagulation of the communicating placental vessels (SLPCV) attempts to mitigate the cardiovascular outcomes. The objective of this study was to characterize early postnatal myocardial performance in MCDA twins with TTTS with and without SLPCV.

METHODS

A prospective study was performed of four MCDA twin groups: (1) uncomplicated MCDA twins, (2) MCDA twins with selective fetal growth restriction, (3) MCDA twins with TTTS following SLPCV (TTTS with SLPCV), and (4) MCDA twins with TTTS who did not undergo SLPCV (TTTS without SLPCV). Fifty-four twin pairs were enrolled: 23 uncomplicated MCDA twin pairs, 15 pairs with selective fetal growth restriction, seven TTTS pairs with SLPCV, and seven TTTS pairs without SLPCV. In each group, twin pairs were divided by birth weight into donor (smaller) and recipient (larger) and compared. Echocardiography was performed on day 1, day 2, and between days 5 and 7 of age, and myocardial performance was characterized by speckle-tracking echocardiography-derived left ventricular and right ventricular longitudinal strain (LS) and systolic strain rate (LSR). Longitudinal strain and longitudinal systolic strain rate are expressed as absolute values.

RESULTS

Compared with all recipient groups, recipient TTTS without SLPCV infants had lower left ventricular LS (16 ± 3% vs 22%-24%, P < .01) and right ventricular LS (15 ± 5% vs 21%-24%, P < .01) on day 1 that persisted throughout the first week of age. Left ventricular LSR (1.7 ± 0.3 vs 2.3 ± 0.3 sec^-1, P < .05) and right ventricular LSR (1.5 ± 0.4 vs 1.7 ± 0.5 sec^-1, P < .05) were both lower in the recipient compared with the donor twin in the TTTS without SLPCV group. LS and LSR measurements were similar among all four donor twin groups.

CONCLUSIONS

Biventricular performance is diminished in recipient MCDA twins with TTTS who are not treated with SLPCV, highlighting the need for close monitoring of their hemodynamic status during the early neonatal period.

Comprehensive Evaluation of Right Heart Performance and Pulmonary Hemodynamics in Neonatal Pulmonary Hypertension : Evaluation of cardiopulmonary performance in neonatal pulmonary hypertension

PURPOSE OF REVIEW

Pulmonary hypertension is characterized by an elevation of pulmonary artery pressures and prolonged exposure of the right ventricle to high afterload that collectively contribute to morbidity and mortality in both the term and preterm infants. This review summarizes the pathogenesis, etiologies, and hemodynamic profiles of the conditions that result in pulmonary hypertension in neonates. We explore the application of echocardiographic techniques for the assessment of right ventricular performance and pulmonary hemodynamics that enhance and guide the diagnosis and management strategies in neonates.

RECENT FINDINGS

Clinical assessments based on the determinants of mean pulmonary artery pressures (pulmonary vascular resistance, pulmonary blood flow, and pulmonary capillary wedge pressure) provide a physiologic approach in determining the acute and chronic etiologies of pulmonary hypertension in neonates. In addition, advances in neonatal echocardiography now afford the capability to obtain quantitative information that often precedes the qualitative information acquired by conventional methods and also provide sensitive markers of right ventricle performance for prognostic information based on the determinants of mean pulmonary artery pressures. Neonatal pulmonary hypertension represents a physiologic spectrum that accounts for the variance in clinical presentation and response to therapies. Physiology-based approaches to etiological identification, coupled with the emerging echocardiographic methods for the assessment of pulmonary hypertension in neonates will likely help to identify cardiovascular compromise earlier, guide therapeutic intervention, monitor therapeutic effectiveness, and improve overall outcome.

Maturational patterns in right ventricular strain mechanics from the fetus to the young infant

AIM

To test the hypothesis that right ventricular (RV) function has age-specific patterns of development, we tracked the evolution of RV strain mechanics by 2D-speckle tracking echocardiography (2DSTE) in healthy subjects from mid-gestation through one year of age.

METHODS

We conducted a prospective longitudinal echocardiography study in 50 healthy subjects at five time periods across gestation (16-20 weeks, 21-25 weeks, 26-30 weeks, 31-35 weeks, and 36-40 weeks) and four time periods following delivery (1 week, 1 month, 6 months, and 1 year of age). We characterized RV function by measuring RV global and free wall longitudinal strain and systolic strain rate, and segmental longitudinal strain at the apical-, mid-, and basal- ventricular levels of the free wall. Possible associations of gestational age, postnatal age, estimated fetal weight, body surface area, gender, and heart rate on strain were investigated.

RESULTS

The magnitudes of RV global and free wall longitudinal strain and global strain rate were decreased throughout gestation (p < 0.05 for all). Following birth, the magnitudes of all measures increased from one week through one year (p < 0.001 for all). RV segmental longitudinal strain maintained a base-to-apex gradient (highest-to-lowest) from mid-gestation through one year (p < 0.001). There was no significant difference in strain patterns based on gender or hear rate.

CONCLUSION

The maturational patterns of RV strain are gestational- and postnatal age- specific. With accepted physiological maturation patterns in healthy subjects, these myocardial deformation parameters can provide a valid basis that allows comparison between health and disease.

Four-Dimensional Ultrasound for Evaluating Newborn Cardiac Output: A Pilot Study of Healthy Infants

BACKGROUND

There is currently no reliable non-invasive method of measuring cardiac output in neonatal intensive care. Spatiotemporal image correlation (STIC) is a novel four-dimensional (4D) ultrasound technique that was developed to assess the foetal heart, and it may be a useful way to assess neonatal haemodynamics.

OBJECTIVE

This study aimed to evaluate the feasibility and reproducibility of determining neonatal cardiac output using STIC ultrasound in newborn infants.

DESIGN

Infants were recruited opportunistically from a neonatal intensive care unit and then examined by 2 independent observers. STIC was used to obtain images of the heart. End-diastolic and end-systolic ventricular volumes were measured using virtual organ computer-aided analysis (VOCAL) and used to calculate cardiac output. Reproducibility was assessed with intraclass correlation coefficients (ICC) and agreement with Bland-Altman analysis.

RESULTS

Twenty-four clinically stable infants of 34-43 weeks corrected gestational age were assessed. Both observers successfully acquired 4D STIC volumes in all infants. Left ventricular output showed good reproducibility, with an intra-observer ICC of 0.86 (0.69-0.94) and inter-observer ICC of 0.87 (0.70-0.95). Right ventricular output also showed good reproducibility, with an intra-observer ICC of 0.88 (0.70-95) and inter-observer ICC of 0.84 (0.63-0.93).

CONCLUSIONS

Determining cardiac output using 4D STIC ultrasound is feasible and reproducible in well newborn infants. With further evaluation, this technique may provide valuable information about haemodynamic status in newborn infants requiring intensive care.

Echocardiographic Measurements of Right Ventricular Mechanics in Infants with Bronchopulmonary Dysplasia at 36 Weeks Postmenstrual Age

OBJECTIVE

To test the hypothesis that specific echocardiographic measurements of right ventricular (RV) mechanics at 36 weeks postmenstrual age (PMA) are associated with the severity of bronchopulmonary dysplasia (BPD).

STUDY DESIGN

A subset of 93 preterm infants (born between 27 and 29 weeks of gestation) was selected retrospectively from a prospectively enrolled cohort. BPD was defined using the National Institutes of Health workshop definition, with modifications for oxygen reduction testing and altitude. The cohort was divided into no-BPD and BPD groups using previously published methodology for analyses. Echocardiographic measurements of RV function (ie, tricuspid annular plane systolic excursion, fractional area of change, systolic-to-diastolic ratio, tissue Doppler myocardial performance index, and RV strain), RV remodeling/morphology (end-systolic left ventricular eccentricity index), and RV afterload (pulmonary artery acceleration time measure) were evaluated at 36 weeks PMA. Multivariable logistic regression determined associations between RV measurements and BPD severity.

RESULTS

Compared with the no-BPD cohort, the BPD group had lower birth weight z-scores (P = .04) and trended toward a male predominance (P = .08). After adjusting for birth weight z-score, gestational age, and sex, there were no between-group differences in echocardiographic measurements except for the eccentricity index (scaled OR [0.1-unit increase], 1.49; 95% CI, 1.13-2.12; P = .01).

CONCLUSIONS

Among conventional and emerging echocardiographic measurements of RV mechanics, eccentricity index was the sole variable independently associated with BPD severity in this study. The eccentricity index may be a useful echocardiographic measurement for characterizing RV mechanics in patients with BPD at 36 weeks PMA.

Early Postnatal Ventricular Dysfunction Is Associated with Disease Severity in Patients with Congenital Diaphragmatic Hernia

OBJECTIVE

To assess patterns of postnatal ventricular function and their relationship to prenatal and postnatal markers of disease severity in infants with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

In this observational case-control study of cardiac function in infants with CDH in the first 5 days of life, systolic and diastolic function in the right ventricle (RV) and left ventricle (LV) were assessed using speckle tracking echocardiography-derived global strain and tissue Doppler imaging. Correlation between cardiac function and prenatal observed:expected total fetal lung volume (TFLV), oxygenation index (OI), duration of intubation, and hospital length of stay were assessed.

RESULTS

All measures of systolic and diastolic function were significantly reduced in the CDH group (n = 25) compared with controls (n = 20) at <48 hours, and were improved by 72-120 hours. LV global systolic longitudinal strain (GLS) correlated with prenatal TFLV (R² = 0.32; P = .03), OI (R² = 0.35; P < .001), duration of intubation (R² = 0.24; P = .04), and length of stay (R² = 0.4; P = .006). Mean (SD) LV GLS at <48 hours was significantly lower in infants with CDH who did not survive and/or required ECMO compared with those who did not: -11.5 (5.3)% vs -16.9 (5.3)% (P = .02).

CONCLUSIONS

RV and LV function are impaired in the transitional period in infants with CDH. Early LV systolic function correlates with prenatal and postnatal markers of clinical disease severity and may be an important determinant of disease severity and therapeutic target in CDH. These findings support regular assessment of cardiac function in CDH and investigational trials of targeted cardiovascular therapies.

Early diastolic dysfunction and respiratory morbidity in premature infants: an observational study

OBJECTIVE

To test if diastolic dysfunction measured on day one of age is associated with the need for invasive ventilation in preterm infants.

STUDY DESIGN

We conducted a retrospective observational tissue Doppler echocardiographic study over the first 12 h of age for infants born <32 weeks who were invasively ventilated, and infants on continuous positive pressure ventilation (CPAP).

RESULTS

One hundred and eighty-three infants were included (27 ± 2 weeks and 999 ± 296 g). Invasively ventilated infants [(n = 96 (53%)] had lower left ventricular (LV) e' (3.4 ± 1.0 vs. 4.1 ± 1.5 cm/s, p < 0.01) and lower LV ea' ratio (0.8 ± 0.2 vs. 1.0 ± 0.4, p < 0.01), even after adjusting for common neonatal confounders (LV e' adjusted OR 0.62, 95% CI 0.45 - 0.87, p < 0.01; LV ea' adjusted OR 0.14, 95% CI 0.03-0.68, p = 0.01).

CONCLUSION

LV diastolic dysfunction is independently associated with a higher risk for invasive ventilation on day one of age.

Hypotension in small preterms: what does it mean?

Introduction: Small preterms often have low blood pressure readings in the first few days of life. However, what is hypotension in preterms? Should there be an aggressive approach to its management? What are the immediate and long-term side effects of powerful medications? Alternatively, could a low blood pressure be accepted instead? Materials and methods: Data were collected from files of all live babies with gestational age (GA) between 23^0/7 and 31^6/7 weeks over two different periods: years 2000-2004 and 2008-2012. Results: Our data show that, despite extremely low gestational age (ELGA)/extremely low birth weight (ELBW) neonates, almost half of these tiny babies have neither low mean arterial pressure (MAP) readings nor clinical signs of impaired perfusion. Yet, many of them are, variously treated or not, depending on individual decisions, rather than on sound evidence. Discussion: We suggest, should it be required to treat persistent hypotension, rather than treating just a low MAP recording, to address the whole issue of hypotension in the overall picture of clinical settings; we to assess organ dysfunction caused by low output and use the least aggressive measures, preferably within written protocols, tailored to the given unit, but equally, sufficiently flexible to individual babies. Furthermore, allow for "permissive hypotension" especially if transient, in the absence of clinical signs of hypoperfusion, with normal superior vena cava (SVC) flow, normal cardiac output, and normal brain scanning with normal cerebral Doppler flows. Whether treating hypotension, by whichever definition, "per se", will make any difference to both, immediate and late outcomes; in the end, treating remains open to questioning and calls for careful follow-up of these very susceptible preterms.

The Impact of Maternal Gestational Hypertension and the Use of Anti-Hypertensives on Neonatal Myocardial Performance

BACKGROUND

Assessment of myocardial performance in neonates using advanced techniques such as deformation imaging and rotational mechanics has gained considerable interest. The applicability of these techniques for elucidating abnormal myocardial performance in various clinical scenarios is becoming established. We hypothesise that term infants born to mothers with gestational hypertension (GH) may experience impaired performance of the left and right ventricles during the early neonatal period.

OBJECTIVES

We aimed to assess left and right ventricular (LV and RV) function using echocardiography in infants born to mothers with GH and compare them to a control group.

METHODS

Term infants (>36+6 weeks) born to mothers with GH underwent assessment to measure biventricular function using ejection fraction (EF), deformation imaging, left-ventricle rotational mechanics (apical rotation, basal rotation, twist, twist rate, and untwist rate), and right ventricle-specific functional parameters (tricuspid annular plane systolic excursion and fractional area change) in the first 48 h after birth. A control group comprising infants born to healthy mothers was used for comparison.

RESULTS

Fifteen infants with maternal GH and 30 age-matched controls were enrolled. The GH infants exhibited no differences in birthweight or LV or RV length, but they had lower EF (54 vs. 61%; p < 0.01), LV global longitudinal strain (-20 vs. -25%; p < 0.01), and LV twist (11 vs. 16°; p = 0.04). There were no differences in any of the RV functional parameters.

CONCLUSION

Infants born to mothers with GH exhibited lower LV function than healthy controls, while RV function appeared to be preserved. This relationship warrants further exploration in a larger cohort.