Right ventricular echocardiographic indices predict poor outcomes in infants with persistent pulmonary hypertension of the newborn

The increased longitudinal basal-to-apical strain ratio in the right ventricular free wall is associated with neonatal pulmonary hypertension

It has been a challenging work to identify and assess neonatal pulmonary hypertension (PH). Right ventricular longitudinal strain (RVLS) is primarily used in evaluating right ventricular (RV) systolic function. This study aimed to investigate the association of the changes in segmental and global RVLS with neonatal PH, hoping to provide a new marker for indicating neonatal PH other than obtaining information on RV function. This was a cross-sectional study with 62 neonates, generally divided into PH and non-PH groups confirmed by echocardiography. For 30 infants later diagnosed with bronchopulmonary dysplasia (BPD), specific analysis was conducted by subdividing them into BPD with and without PH subgroups. Conventional echocardiography markers and the global and segmental RVLS were measured and compared. Their diagnostic performance in evaluating PH was analyzed. Regardless of grouping, the biventricular function of all infants was similar and in normal range. No significant difference was found in global strain parameters, either. In the case of PH, tricuspid regurgitant velocity (TRV), left ventricle systolic eccentricity index (LVsEI), and the basal-to-apical strain ratio (Ratio bas/api) of RV free wall (RVFW) were significantly higher (P < 0.001, P < 0.05, P < 0.05). By contrast, the magnitude of apical segmental strain reduced significantly (P < 0.05) and was significantly lower than that of basal segmental strain in BPD with PH subgroup (P = 0.024). The area under the curve values for Ratio bas/api was highest (0.846), followed by LVsEI (0.746) and apical segmental strain (0.272).

CONCLUSION

As a relatively standardized parameter, Ratio bas/api of RVFW was significantly higher in the case of neonatal PH with normal cardiac function and could be regarded as a new indicator for PH.

WHAT IS KNOWN

• It has been challenging work to diagnose neonatal pulmonary hypertension (PH), and conventional echocardiography has been widely applied, though it is not sufficient enough. • RV longitudinal strain (RVLS) is primarily used to assess RV systolic function, and its role in diagnosing PH was rarely considered.

WHAT IS NEW

• The basal-to-apical strain ratio (Ratio bas/api) of RV free wall increased significantly in all infants with PH regardless of causes. • As a relatively standardized parameter, Ratio bas/api could be regarded as a new indicator for diagnosing PH, apart from conventional echocardiographic parameters.

Progress in the application of echocardiography in neonatal pulmonary hypertension

Purpose: This review aims to overview the use of echocardiography in diagnosing neonatal pulmonary hypertension, assessing cardiac function, and understanding the significance and limitations of various parameters in clinical practice.Materials and methods: Advancements in echocardiography for diagnosing and assessing neonatal pulmonary hypertension, evaluating cardiac function, monitoring treatment effectiveness, and predicting prognosis are discussed.Results: Echocardiography is a pivotal tool for diagnosing and managing neonatal pulmonary hypertension. It should be used with other ultrasound parameters to confirm findings and provide comprehensive analysis for improved accuracy.Conclusion: Understanding the value of echocardiography in neonatal pulmonary hypertension diagnosis and management is crucial. Its integration with other imaging modalities enhances diagnostic accuracy and improves patient outcomes.

Defining the Typical Course of Persistent Pulmonary Hypertension of the Newborn: When to Think Beyond Reversible Causes

OBJECTIVES

To describe the typical clinical course of reversible persistent pulmonary hypertension of the newborn (PPHN) from perinatal etiologies and compare that with the clinical course of PPHN due to underlying fetal developmental etiologies.

STUDY DESIGN

This was a single-center, retrospective cohort study of liveborn newborns either born or transferred to our facility for higher level of care between 2015 and 2020 with gestational age ≥35 weeks and a clinical diagnosis of PPHN in the electronic health record. Newborns with complex congenital heart disease and congenital diaphragmatic hernia were excluded. Using all data available at time of collection, newborns were stratified into 2 groups by PPHN etiology - perinatal and fetal developmental causes. Primary outcomes were age at initiation, discontinuation, and total duration of extracorporeal life support, mechanical ventilation, supplemental oxygen, inhaled nitric oxide, inotropic support, and prostaglandin E1. Our secondary outcome was age at echocardiographic resolution of pulmonary hypertension. Groups were compared by t-test. Time-to-event Kaplan Meier curves described and compared (log-rank test) discontinuation of each therapy.

RESULTS

Sixty-four (72%) newborns had perinatal etiologies whereas 24 (28%) had fetal developmental etiologies. The resolution of perinatal PPHN was more rapid compared with fetal developmental PPHN. By 10 days of age, more neonates were off inotropes (98% vs 29%, P < .01), decannulated from extracorporeal life support (100% vs 0%, P < .01), extubated (75% vs 37%, P < .01), and had echocardiographic resolution of PH (35% vs 7%, P = .02).

CONCLUSIONS

An atypical PPHN course, characterized by persistent targeted therapies in the second week of life, warrants further work-up for fetal developmental causes.

Echocardiographic markers at diagnosis of persistent pulmonary hypertension of the newborn

OBJECTIVES

Clinical parameters along with echocardiographic markers are used to interrogate the haemodynamics in persistent pulmonary hypertension of the newborn (PPHN). The aim of this study was to compare different echocardiographic markers in recent cohort of newborn infants with and without PPHN.

METHODS

In this retrospective study, common echocardiographic markers were examined in infants>34 weeks' gestation with PPHN (cases) and without PPHN (controls). Infants with congenital heart disease were excluded. Binary regression testing was used to evaluate echocardiographic markers predicting PPHN and death. In addition, diagnostic accuracy testing of echocardiographic markers using ROC was also performed. Intra-observer reliability for echocardiographic markers was examined using coefficient of variation (CoV) and intraclass correlation.

RESULTS

Fifty-two infants were studied; 22 (42 %) infants with PPHN had significantly higher oxygen requirement, oxygenation index and ventilation days when compared with controls. Echocardiographic markers such as TR Vmax, S/D TR, PAAT, TAPSE and eccentricity index (EI) were significantly different between cases and controls. Receiver operator characteristics analysis of echocardiographic markers revealed TR Vmax 0.96 (0.9-1.0), S/D TR 0.95 (0.87-1.0) and end systolic EI 0.94 (0.87-1.0). These markers were found to predict death in this cohort of infants. CoV and Intra-observer reliability was good for various echocardiographic markers.

CONCLUSIONS

Among the various echocardiographic markers studied, TR Vmax when present along with S/D TR and end systolic EI had good intra-observer reliability and were diagnostic of PPHN and predicted death in this cohort. Future trials could use these markers in studies examining PPHN.

Association of Right Ventricular Dysfunction with Risk of Neurodevelopmental Impairment in Infants with Pulmonary Hypertension

(1) Background: Pulmonary hypertension (PH) increases pulmonary vascular resistance and right ventricular (RV) afterload. Assessment of RV systolic function in PH using RV fractional area change (RV FAC) as a marker directly correlates with mortality and the need for extracorporeal membrane oxygenation (ECMO). However, few studies have assessed neurodevelopmental outcomes. We hypothesize that cardiac RV systolic dysfunction with lower RV FAC is associated with worse neurodevelopmental impairment (NI). (2) Methods: Retrospective study of 42 subjects with PH to evaluate neurodevelopmental outcomes in the first two years of life based on (i) subjective assessment of RV systolic function and (ii) RV FAC, a specific echocardiographic marker for RV function. (3) Results: Subjects from the initial study cohort (n = 135) with PH who had long-term follow-up were divided into RV dysfunction (study, n = 20) and non-RV dysfunction (control, n = 22) groups. RV FAC in the study vs. control group (0.18 vs. 0.25) was lower (p = 0.00017). There was no statistically significant difference in NI either with RV dysfunction or lower RV FAC. Although not significant, RV dysfunction was associated with longer mean duration of mechanical ventilation, time on ECMO, and length of stay. In the initial cohort (135), mortality was 16.3% and the percentage of NI was 62%. (4) Conclusions: Neonatal pulmonary hypertension is associated with a high degree of neurodevelopment impairment. Early RV systolic dysfunction, as identified by RV FAC, was not an optimal predictive biomarker for infants with PH and neurodevelopmental impairment.

International treatment outcomes of neonates on extracorporeal membrane oxygenation (ECMO) with persistent pulmonary hypertension of the newborn (PPHN): a systematic review

BACKGROUND

PPHN is a common cause of neonatal respiratory failure and is still a serious condition and associated with high mortality.

OBJECTIVES

To compare the demographic variables, clinical characteristics, and treatment outcomes in neonates with PHHN who underwent ECMO and survived compared to neonates with PHHN who underwent ECMO and died.

METHODS

We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and searched ProQuest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature for studies on the development of PPHN in neonates who underwent ECMO, published from January 1, 2010 to May 31, 2023, with English language restriction.

RESULTS

Of the 5689 papers that were identified, 134 articles were included in the systematic review. Studies involving 1814 neonates with PPHN who were placed on ECMO were analyzed (1218 survived and 594 died). Neonates in the PPHN group who died had lower proportion of normal spontaneous vaginal delivery (6.4% vs 1.8%; p value > 0.05) and lower Apgar scores at 1 min and 5 min [i.e., low Apgar score: 1.5% vs 0.5%, moderately abnormal Apgar score: 10.3% vs 1.2% and reassuring Apgar score: 4% vs 2.3%; p value = 0.039] compared to those who survived. Neonates who had PPHN and died had higher proportion of medical comorbidities such as omphalocele (0.7% vs 4.7%), systemic hypotension (1% vs 2.5%), infection with Herpes simplex virus (0.4% vs 2.2%) or Bordetella pertussis (0.7% vs 2%); p = 0.042. Neonates with PPHN in the death group were more likely to present due to congenital diaphragmatic hernia (25.5% vs 47.3%), neonatal respiratory distress syndrome (4.2% vs 13.5%), meconium aspiration syndrome (8% vs 12.1%), pneumonia (1.6% vs 8.4%), sepsis (1.5% vs 8.2%) and alveolar capillary dysplasia with misalignment of pulmonary veins (0.1% vs 4.4%); p = 0.019. Neonates with PPHN who died needed a longer median time of mechanical ventilation (15 days, IQR 10 to 27 vs. 10 days, IQR 7 to 28; p = 0.024) and ECMO use (9.2 days, IQR 3.9 to 13.5 vs. 6 days, IQR 3 to 12.5; p = 0.033), and a shorter median duration of hospital stay (23 days, IQR 12.5 to 46 vs. 58.5 days, IQR 28.2 to 60.7; p = 0.000) compared to the neonates with PPHN who survived. ECMO-related complications such as chylothorax (1% vs 2.7%), intracranial bleeding (1.2% vs 1.7%) and catheter-related infections (0% vs 0.3%) were more frequent in the group of neonates with PPHN who died (p = 0.031).

CONCLUSION

ECMO in the neonates with PPHN who failed supportive cardiorespiratory care and conventional therapies has been successfully utilized with a neonatal survival rate of 67.1%. Mortality in neonates with PPHN who underwent ECMO was highest in cases born via the caesarean delivery mode or neonates who had lower Apgar scores at birth. Fatality rate in neonates with PPHN who underwent ECMO was the highest in patients with higher rate of specific medical comorbidities (omphalocele, systemic hypotension and infection with Herpes simplex virus or Bordetella pertussis) or cases who had PPHN due to higher rate of specific etiologies (congenital diaphragmatic hernia, neonatal respiratory distress syndrome and meconium aspiration syndrome). Neonates with PPHN who died may need a longer time of mechanical ventilation and ECMO use and a shorter duration of hospital stay; and may experience higher frequency of ECMO-related complications (chylothorax, intracranial bleeding and catheter-related infections) in comparison with the neonates with PPHN who survived.

Challenges in clinical identification of right ventricular dysfunction in preterm infants with persistent pulmonary hypertension of the newborn

BACKGROUND

Right ventricular dysfunction, typically qualitatively diagnosed (Q-RVd) in preterm infants, requires echocardiography which is not always acutely available. We aimed to identify clinical indices of Q-RVd in very preterm infants (gestational age, GA <32 weeks) with persistent pulmonary hypertension of newborn (PPHN) and examine the reliability and validity of Q-RVd.

METHODS

Forty-seven infants with mean ± SD GA of 26.8 ± 2.7 weeks who had targeted neonatal echocardiography (TNE) ≤72 h old, during PPHN, were retrospectively studied. Three standard TNE clips were reviewed by two blinded assessors, and infants categorized as Q-RVd if moderate-severe RVd was diagnosed on ≥2 clips. Cardiopulmonary clinical indices at TNE and quantitative RV functional markers were compared between Q-RVd vs. no-RVd groups. Potential quantitative RVd definitions examined by classifying each measurement as "low" or "normal" using published data. Inter-rater agreement for Q-RVd assessed using Kappa statistics.

RESULTS

Mean age at TNE was 25.3 ± 20.4 h with Q-RVd diagnosed in 19(40 %) infants. Q-RVd group demonstrated higher peak oxygen requirements (96 ± 9 % vs. 84 ± 16 %, p < 0.01); however, no clinical parameters at TNE differentiated the groups. Quantitative measures were lower in Q-RVd patients, confirming classification validity. Among tested quantitative definitions, low RV stroke volume was associated with lower systolic blood pressure (41±7 vs. 47±9 mmHg, p = 0.02) and higher shock index (4.02±0.80 vs. 3.44±0.72, p = 0.02). Kappa for Q-RVd was 0.55 (95%CI 0.32-0.77).

CONCLUSIONS

The non-specific nature of clinical markers of RVd in preterm infants with PPHN necessitates echocardiographic diagnosis of RVd. Studies should examine prognostic relevance of RVd and establish outcome-based quantitative definitions in preterm infants.

Guidelines and Recommendations for Targeted Neonatal Echocardiography and Cardiac Point-of-Care Ultrasound in the Neonatal Intensive Care Unit: An Update from the American Society of Echocardiography

Targeted neonatal echocardiography (TNE) involves the use of comprehensive echocardiography to appraise cardiovascular physiology and neonatal hemodynamics to enhance diagnostic and therapeutic precision in the neonatal intensive care unit. Since the last publication of guidelines for TNE in 2011, the field has matured through the development of formalized neonatal hemodynamics fellowships, clinical programs, and the expansion of scientific knowledge to further enhance clinical care. The most common indications for TNE include adjudication of hemodynamic significance of a patent ductus arteriosus, evaluation of acute and chronic pulmonary hypertension, evaluation of right and left ventricular systolic and/or diastolic function, and screening for pericardial effusions and/or malpositioned central catheters. Neonatal cardiac point-of-care ultrasound (cPOCUS) is a limited cardiovascular evaluation which may include line tip evaluation, identification of pericardial effusion and differentiation of hypovolemia from severe impairment in myocardial contractility in the hemodynamically unstable neonate. This document is the product of an American Society of Echocardiography task force composed of representatives from neonatology-hemodynamics, pediatric cardiology, pediatric cardiac sonography, and neonatology-cPOCUS. This document provides (1) guidance on the purpose and rationale for both TNE and cPOCUS, (2) an overview of the components of a standard TNE and cPOCUS evaluation, (3) disease and/or clinical scenario-based indications for TNE, (4) training and competency-based evaluative requirements for both TNE and cPOCUS, and (5) components of quality assurance. The writing group would like to acknowledge the contributions of Dr. Regan Giesinger who sadly passed during the final revisions phase of these guidelines. Her contributions to the field of neonatal hemodynamics were immense.

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.

Novel scoring tool of hypoxemic respiratory failure and pulmonary hypertension for defining severity of persistent pulmonary hypertension of newborn

OBJECTIVE

To obtain preliminary validity data for a hypoxemic respiratory failure/pulmonary hypertension (HRF/PH) score for classifying persistent pulmonary hypertension of the newborn (PPHN).

STUDY DESIGN

Retrospective chart review of 100 consecutive neonates admitted to a Children's hospital from 2016-2021 with PPHN, gestational age ≥34 weeks, and echocardiograms in the first week. We assessed the correlation between HRF/PH score and short-term outcomes using linear and logistic regressions.

RESULTS

HRF/PH scores ranged 2-12 (mean 8.5), and were classified mild (0-5), moderate (6-10), and severe (11-15), with 6%, 77% and 17% infants in respective categories. HRF/PH score category correlated with invasive ventilation, nitric oxide, high frequency ventilation, vasoactive infusions, extracorporeal life support and death. HRF/PH score category did not correlate with duration of support or length of stay.

CONCLUSION

The HRF/PH score offers a promising representation of disease severity for PPHN. The tool requires further validation in prospective studies and evaluation for long-term outcomes.

Diastolic ventricular function in persistent pulmonary hypertension of the newborn

Background

Persistent pulmonary hypertension of the newborn (PPHN) is usually considered a consequence of impaired pulmonary circulation. However, little is known regarding the role of cardiac dysfunction in PPHN. In this study, we hypothesized that the tolerance for pulmonary hypertension in newborn infants depends on the biventricular function. The aim of this study is to evaluate biventricular cardiac performance by using Tissue Doppler Imaging (TDI) in an healthy newborn infants with asymptomatic pulmonary hypertension and in newborn infants with PPHN.

Methods

Right and left cardiac function were investigated using conventional imaging and TDI in 10 newborn infants with PPHN ("PPHN") and 10 asymptomatic healthy newborn infants ("asymptomatic PH").

Results

Systolic pulmonary artery pressure (PAP) as assessed by TDI and the mean systolic velocity of the right ventricular (RV) free wall were similar in both groups. The isovolumic relaxation time of the right ventricle at the tricuspid annulus was significantly longer in the "PPHN" than in the "asymptomatic PH" group (53 ± 14 ms vs. 14 ± 4 ms, respectively; p < 0.05). Left ventricular (LV) function was normal in both groups with a systolic velocity (S'LV) at the LV free wall groups (6 ± 0.5 cm/s vs. 8.3 ± 5.7 cm/s, p > 0.05).

Conclusion

The present results suggest that high PAP with or without respiratory failure is not associated with altered right systolic ventricular function and does not affect LV function in newborn infants. PPHN is characterized by a marked right diastolic ventricular dysfunction. These data suggest that the hypoxic respiratory failure in PPHN results, at least in part, from diastolic RV dysfunction and right to left shunting across the foramen ovale. We propose that the severity of the respiratory failure is more related to the RV diastolic dysfunction than the pulmonary artery pressure.

Pulmonary vasodilator strategies in neonates with acute hypoxemic respiratory failure and pulmonary hypertension

The management of acute hypoxemic respiratory failure (AHRF) in newborns continues to be a clinical challenge with elevated risk for significant morbidities and mortality, especially when accompanied with persistent pulmonary hypertension of the newborn (PPHN). PPHN is a syndrome characterized by marked hypoxemia secondary to extrapulmonary right-to-left shunting across the ductus arteriosus and/or foramen ovale with high pulmonary artery pressure and increased pulmonary vascular resistance (PVR). After optimizing respiratory support, cardiac performance and systemic hemodynamics, targeting persistent elevations in PVR with inhaled nitric oxide (iNO) therapy has improved outcomes of neonates with PPHN physiology. Despite aggressive cardiopulmonary management, a significant proportion of patients have an inadequate response to iNO therapy, prompting consideration for additional pulmonary vasodilator therapy. This article reviews the pathophysiology and management of PPHN in term newborns with AHRF while highlighting both animal and human data to inform a physiologic approach to the use of PH-targeted therapies.

Early diagnosis and targeted approaches to pulmonary vascular disease in bronchopulmonary dysplasia

Pulmonary hypertension has emerged as a life-threatening disease in preterm infants suffering from bronchopulmonary dysplasia (BPD). Its development is closely linked to respiratory disease, as vasculogenesis and alveologenesis are closely interconnected. Once clinically significant, BPD-associated pulmonary hypertension (BPD-PH) can be challenging to manage, due to poor reversibility and multiple comorbidities frequently associated. The pulmonary vascular disease process underlying BPD-PH is the result of multiple innate and acquired factors, and emerging evidence suggests that it progressively develops since birth and, in certain instances, may begin as early as fetal life. Therefore, early recognition and intervention are of great importance in order to improve long-term outcomes. Based on the most recent knowledge of BPD-PH pathophysiology, we review state-of-the-art screening and diagnostic imaging techniques currently available, their utility for clinicians, and their applicability and limitations in this specific population. We also discuss some biochemical markers studied in humans as a possible complement to imaging for the detection of pulmonary vascular disease at its early stages and the monitoring of its progression. In the second part, we review pharmacological agents currently available for BPD-PH treatment or under preclinical investigation, and discuss their applicability, as well as possible approaches for early-stage interventions in fetuses and neonates. IMPACT: BPD-associated PH is a complex disease involving genetic and epigenetic factors, as well as environmental exposures starting from fetal life. The value of combining multiple imaging and biochemical biomarkers is emerging, but requires larger, multicenter studies for validation and diffusion. Since "single-bullet" approaches have proven elusive so far, combined pharmacological regimen and cell-based therapies may represent important avenues for research leading to future cure and prevention.

Echocardiographic measures of ventricular-vascular interactions in congenital diaphragmatic hernia

OBJECTIVE

To evaluate the utility of echocardiographic measures of ventricular-vascular interactions in predicting death or ECMO in congenital diaphragmatic hernia (CDH).

DESIGN

In this single center retrospective study, early (<48 hour age) Doppler ECHOs of neonates (≥34 weeks gestation) with CDH (n = 58) were reviewed. ECHO measures of the relationship of right ventricular (RV) contractility and pulmonary hypertension (PH) were selected: Ratios of 1. pulmonary artery acceleration time to pulmonary ejection time (PAAT/PET) 2. tricuspid annular plane systolic excursion, a measure of regional RV function, to PAAT (TAPSE/PAAT) 3. patent ductus arteriosus (PDA) flow velocity time integral (VTI) from right to left (PDA/RLVTI) 4. PDA flow duration from right to left (PDA/RL) and 5. TAPSE to RV systolic pressure (TAPSE/RVSP). Statistical analyses included t-test and chi-square test and receiver operating characteristic curves were generated.

RESULTS

Our cohort (n = 58) comprised 34 (59%) males and predominantly (81%) left sided CDH. Of these, 34 (58.6%) infants died or received ECMO and 24 (41.4%) survived without ECMO. RVSP and PDA/RL VTI were higher, and RV TAPSE, PAAT/PET, TAPSE/PAAT and TAPSE/RVSP ratios were all significantly lower in the death/ECMO group. PDA/RLVTI ratio had the highest area under the curve (0.76); values ≥ 0.6 had high specificity [88% (95% C.I. 62-98%)] and positive predictive value [88% (95% C.I. 65-96%)] for adverse outcomes.

CONCLUSION(S)

Novel early ECHO parameters which combine RV function and PH severity were found to be feasible and prognostic in CDH. A detailed non-invasive assessment of ventricular-vascular interactions is important for risk-stratification in this population.

Right Ventricular Volumes, Ejection Fraction, and Systolic Function Indices in Normal Neonates by Three-Dimensional Speckle-Tracking Echocardiography

The aim of this study was to test the feasibility of measuring right ventricular (RV) volumes, ejection fraction (EF), and systolic function indices in neonates using three-dimensional speckle-tracking echocardiography (3D-STE). Thirty-eight neonates underwent complete echocardiographic evaluation, including the acquisition of three full-volume 3D datasets or more from each of the apical, parasternal, and subcostal windows while naturally sleeping. Datasets were analyzed using a commercially available software (Tomtec). Global RV 3D volumes and EF were measured. In addition, 2D free wall longitudinal strain (LS), tricuspid valve annulus (TVA), tricuspid annular plane systolic excursion (TAPSE) and its index to RV length (TAPSEi), and fractional area change (FAC) were obtained from a non-shortened apical 4-chamber view of the RV, derived from the 3D dataset. Three or more datasets obtained from the apical window were available for analysis for each subject. At least one dataset was adequate for analysis in all subjects. Mean indexed 3D diastolic, systolic, stroke volumes, and EF were measured at 28.5 ± 3.4 ml/m², 13 ± 2.0 ml/m², 15.6 ± 1.9 ml/m², and 54.6 ± 3.2%, respectively. Free wall 2D LS was calculated at (- 27.9 ± 2.5%). In addition, mean TVA measured 11.1 ± 0.8 mm, TAPSE measured 6.8 ± 0.9 mm, and TAPSEi and FAC were calculated at 24.2 ± 2.1 and 46 ± 3.4%, respectively. 3D-STE is feasible in normal neonates without the need for sedation. Reference values of RV 3D volumes and 2D indices of systolic function were obtained. These data could be helpful in patients where the size or systolic function of the RV is in question. Larger studies are required to establish nomograms for the above indices in this age group.

Pediatric Pulmonary Hypertension: Definitions, Mechanisms, Diagnosis, and Treatment

Pediatric pulmonary hypertension (PPH) is a multifactorial disease with diverse etiologies and presenting features. Pulmonary hypertension (PH), defined as elevated pulmonary artery pressure, is the presenting feature for several pulmonary vascular diseases. It is often a hidden component of other lung diseases, such as cystic fibrosis and bronchopulmonary dysplasia. Alterations in lung development and genetic conditions are an important contributor to pediatric pulmonary hypertensive disease, which is a distinct entity from adult PH. Many of the causes of pediatric PH have prenatal onset with altered lung development due to maternal and fetal conditions. Since lung growth is altered in several conditions that lead to PPH, therapy for PPH includes both pulmonary vasodilators and strategies to restore lung growth. These strategies include optimal alveolar recruitment, maintaining physiologic blood gas tension, nutritional support, and addressing contributing factors, such as airway disease and gastroesophageal reflux. The outcome for infants and children with PH is highly variable and largely dependent on the underlying cause. The best outcomes are for neonates with persistent pulmonary hypertension (PPHN) and reversible lung diseases, while some genetic conditions such as alveolar capillary dysplasia are lethal. © 2021 American Physiological Society. Compr Physiol 11:2135-2190, 2021.

Multicentre prospective observational study exploring the predictive value of functional echocardiographic indices for early identification of preterm neonates at risk of developing chronic pulmonary hypertension secondary to chronic neonatal lung disease

INTRODUCTION

Although chronic pulmonary hypertension (cPH) secondary to chronic neonatal lung disease is associated with increased mortality and respiratory and neurodevelopmental morbidities, late diagnosis (typically ≥36 weeks postmenstrual age, PMA) and the use of qualitative echocardiographic diagnostic criterion (flat interventricular septum in systole) remain significant limitations in clinical care. Our objective in this study is to evaluate the utility of relevant quantitative echocardiographic indices to identify cPH in preterm neonates, early in postnatal course and to develop a diagnostic test based on the best combination of markers.

METHODS AND ANALYSIS

In this ongoing international prospective multicentre observational diagnostic accuracy study, we aim to recruit 350 neonates born <27 weeks PMA and/or birth weight <1000 g and perform echocardiograms in the third week of age and at 32 weeks PMA (early diagnostic assessments, EDA) in addition to the standard diagnostic assessment (SDA) for cPH at 36 weeks PMA. Predefined echocardiographic markers under investigation will be measured at each EDA and examined to create a scoring system to identify neonates who subsequently meet the primary outcome of cPH/death at SDA. Diagnostic test characteristics will be defined for each EDA. Pulmonary artery acceleration time and tricuspid annular plane systolic excursion are the primary markers of interest.

ETHICS AND DISSEMINATION

Ethics approval has been received by the Mount Sinai Hospital Research Ethics Board (REB) (#16-0111-E), Sunnybrook Health Sciences Centre REB (#228-2016), NHS Health Research Authority (IRAS 266498), University of Iowa Human Subjects Office/Institutional Review Board (201903736), Rotunda Hospital Research and Ethics Committee (REC-2019-008), and UBC Children's and Women's REB (H19-02738), and is under review at Boston Children's Hospital Institutional Review Board. Study results will be disseminated to participating families in lay format, presented to the scientific community at paediatric and critical care conferences and published in relevant peer-reviewed journals.

TRAIL REGISTRATION NUMBER

NCT04402645.

Persistent pulmonary hypertension of the newborn

Persistent pulmonary hypertension of the newborn (PPHN) is a significant clinical problem characterized by refractory and severe hypoxemia secondary to elevated pulmonary vascular resistance resulting in right-to-left extrapulmonary shunting of deoxygenated blood. PPHN is associated with diverse cardiopulmonary disorders and a high early mortality rate for infants with severe PPHN. Surviving infants with PPHN have an increased risk of long-term morbidities. PPHN physiology can be categorized by (1) maladaptation: pulmonary vessels have normal structure and number but have abnormal vasoreactivity; (2) excessive muscularization: increased smooth muscle cell thickness and increased distal extension of muscle to vessels that are usually not muscularized; and (3) underdevelopment: lung hypoplasia associated with decreased pulmonary artery number. Treatment involves adequate lung recruitment, optimization of cardiac output and left ventricular function, and pulmonary vasodilators such as inhaled nitric oxide. Infants who fail to respond to conventional therapy should be evaluated for lethal lung disorders including alveolar-capillary dysplasia, T-box transcription factor 4 gene, thyroid transcription factor-1, ATP-binding cassette A3 gene, and surfactant protein diseases.

Intervendor Agreement for Right Ventricular Global Longitudinal Strain in Children

BACKGROUND

Right ventricular global longitudinal strain (RVGLS) has emerged as an important technique for clinical evaluation of (RV) function. The routine application of RVGLS in pediatrics remains limited by a lack of data on agreement between vendors. The aim of this study was to investigate intervendor agreement for RVGLS between the two commonly used analysis vendors in pediatrics, hypothesizing that RVGLS has good intervendor agreement, although it is likely lower than intravendor agreement (inter- and intraobserver reproducibility).

METHODS

Seventy infants and children with normal cardiac anatomy and varying ventricular function were included after prospectively obtaining RV-focused four-chamber apical images on the GE Vivid E95. Images were analyzed for RVGLS at acquired frame rates in EchoPAC (GE) and TomTec (TT) and in the compressed Digital Imaging and Communications in Medicine format in TT. Intraclass correlation coefficients and Bland-Altman plots were used to test intervendor agreement and intravendor reproducibility.

RESULTS

RVGLS measurements were equally feasible using TT and EchoPAC analysis (92%). There was good to excellent agreement for RVGLS between TT and EchoPAC analysis, with a relatively higher intraclass correlation coefficient between GE and TT at the acquired frame rate (0.85) than between GE and TT at the compressed frame rate (0.75) and significantly higher agreement in patients with abnormal RV function (0.7-0.9) than those with normal function (0.4-0.6). Intra- andinterobserver reproducibility for RVGLS was excellent (intraclass correlation coefficient = 0.74-0.96). Heart rate ≥ 100 beats/min and acquisition frame rate/heart rate ≤ 0.7 were associated with diminished agreement, especially when compressed data were involved.

CONCLUSIONS

RVGLS analyzed using EchoPAC and TT show good agreement, especially when analyzed at acquisition frame rates and in the setting of abnormal RV function. Otherwise, RVGLS should ideally be analyzed using the same vendor, and intervendor comparisons should be undertaken with caution, particularly if data are in a compressed format.

Cardiac Function and Ventricular Interactions in Persistent Pulmonary Hypertension of the Newborn

OBJECTIVES

The aim of this study was to use a comprehensive imaging protocol to identify echocardiographic correlations of right and left ventricular size, function, and hemodynamics in neonates with persistent pulmonary hypertension of newborn and describe their relationship with key clinical variables.

DESIGN

Retrospective case-control echocardiography-based study of persistent pulmonary hypertension of newborn.

SETTING

A tertiary neonatal ICU in Canada.

PATIENTS

Forty-nine neonates (gestational age ≥ 35 wk old) diagnosed with persistent pulmonary hypertension of newborn within first 3 days after birth and 50 age-matched controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The echocardiographic measurements comprised of right ventricular and left ventricular functional markers, including tricuspid annular plane systolic excursion, fractional area change, tissue Doppler imaging, and deformation imaging. Sample size was based on detecting an intergroup difference of 10% in tricuspid annular plane systolic excursion, which was considered the primary outcome. Linear correlations between the right and left ventricular indices, as well as their association with the outcome of death or extracorporeal membrane oxygenation were evaluated. Persistent pulmonary hypertension of newborn was associated with lower tricuspid annular plane systolic excursion (6.81 ± 1.92 vs 9.25 ± 1.30 mm), right-ventricular global longitudinal strain (16.9% ± 5.4% vs -21.6% ± 4.6%); left ventricular ejection fraction (49% ± 7% vs 55% ± 6%), left ventricular global longitudinal strain (-16.7% ± 3.3% vs -21.4% ± 2.0%) (all p < 0.01). Right and left ventricular diastolic and global function was also lower in persistent pulmonary hypertension of newborn, with more pronounced changes seen for the right ventricle. Moderate-to-strong linear correlations were observed between the right and left ventricular functional markers, with right ventricular global longitudinal strain and left ventricular global longitudinal strain being the strongest (r = 0.8). Within persistent pulmonary hypertension of newborn group, hypoxic ischemic encephalopathy was associated with lower right and left ventricular systolic and right ventricular diastolic performance. Tricuspid annular plane systolic excursion (p =0.08) and left ventricular systolic velocity (p = 0.09) tended to be lower in patients who subsequently died/needed extracorporeal membrane oxygenation.

CONCLUSIONS

Persistent pulmonary hypertension of newborn is characterized by global cardiac dysfunction, involving both the right and left ventricles, with significant interventricular functional correlation. Cardiac dysfunction early in disease course may identify patients at highest risk of adverse outcome.

Echocardiographic Parameters Predictive of Poor Outcome in Persistent Pulmonary Hypertension of the Newborn (PPHN): Preliminary Results

The aim is to conduct a pilot study to prospectively describe echocardiographic parameters in neonates with pulmonary hypertension (PH) managed according to current recommendations and to identify those parameters that could predict worsening of short-term outcomes. All neonates less than 28 days old with a diagnosis of PH were prospectively enrolled in a tertiary care center for 1 year. Two echocardiograms were performed by a trained neonatologist. The first echocardiogram was performed at the time of diagnosis, whereas the second was performed just after basic therapeutic optimization. The cohort included 27 neonates. Mean gestational age at birth was 36.1 weeks gestational age (WGA) (SD: 4) and mean birth weight was 2658 g (SD: 907). Six neonates (22%) died before day 28, with a median age at death of 48 h (IQR [33; 89]). Although the first echocardiogram showed no difference, the second highlighted a strong link between the persistence of right-to left-shunt and death (p = 0.002). We showed a link between right-to-left shunt and a poor outcome (death or morbidity) after therapeutic optimization among premature and full-term neonates suffering from PH. We recommend repeating echocardiography after basic therapeutic optimization and for prognostic purposes, taking into account only the second examination. Larger cohorts are needed to confirm these results.

Survival and associated risk factors for mortality among infants with persistent pulmonary hypertension of the newborn in Malaysia

OBJECTIVE

This study aims to determine the immediate outcome of persistent pulmonary hypertension of the newborn (PPHN) and risk factors for mortality in the era of inhaled nitric oxide (iNO).

STUDY DESIGN

This observational cross-sectional study includes 195 confirmed PPHN with a gestational age of ≥34 weeks without congenital heart disease. Multivariable logistic regression was used to identify risk factors for mortality.

RESULTS

The mortality rate was 16.4%, with the highest mortality with pulmonary hypoplasia. Of 195, 65% received iNO; 18% were iNO non-responders with the majority having pulmonary hypoplasia. Independent risk factors for mortality were the presence of reversal of flow at the descending aorta, pulmonary hypoplasia, APGAR scores ≤ 5 at 5 min, and idiopathic PPHN with an adjusted odds ratio of 15.9, 7.5, 6.7, and 6.4, respectively.

CONCLUSIONS

Despite the usage of iNO, mortality due to PPHN remains high and is related to etiology and cardiac function.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Impaired Right Ventricular Performance Is Associated with Adverse Outcome after Hypoxic Ischemic Encephalopathy

Rationale: Asphyxiated neonates with hypoxic ischemic encephalopathy (HIE) are at risk of myocardial dysfunction; however, echocardiography studies are limited and little is known about the relationship between hemodynamics and brain injury.Objectives: To analyze the association between severity of myocardial dysfunction and adverse outcome as defined by the composite of death and/or abnormal magnetic resonance imaging.Methods: Neonates with HIE undergoing therapeutic hypothermia were enrolled. Participants underwent echocardiography at 24 hours, 72 hours (before rewarming), and 96 hours (after rewarming). Cerebral hemodynamics were monitored by near-infrared spectroscopy and middle cerebral artery Doppler.Measurements and Main Results: Fifty-three patients with a mean gestation and birthweight of 38.8 ± 2.0 weeks and 3.33 ± 0.6 kg, respectively, were recruited. Thirteen patients (25%) had mild encephalopathy, 27 (50%) had moderate encephalopathy, and 13 (25%) had severe encephalopathy. Eighteen patients (34%) had an adverse outcome. Severity of cardiovascular illness (P < 0.001) and severity of neurologic insult (P = 0.02) were higher in neonates with adverse outcome. Right ventricle (RV) systolic performance at 24 hours was substantially lower than published normative data in all groups. At 24 hours, lower tricuspid annular plane systolic excursion (P = 0.004) and RV fractional area change (P < 0.001), but not pulmonary hypertension, were independently associated with adverse outcome on logistic regression. High brain regional oxygen saturation (P = 0.007) and low middle cerebral artery resistive index (P = 0.04) were associated with RV dysfunction on post hoc analysis.Conclusions: RV dysfunction is associated with the risk of adverse outcome in asphyxiated patients with HIE undergoing hypothermia. Echocardiography may be a valuable diagnostic and prognostic tool in this vulnerable population.

Individualized Hemodynamic Management in Newborns

In our aim to improve patient outcome we are transitioning from a "one-size-fits-all" protocolized approach toward an individualized hemodynamic management, that is tailored to the cardiovascular (patho-)physiology and the specific clinical characteristics of each individual patient. In this narrative review an overview is provided about an individualized approach toward various neonatal hemodynamic conditions.

Association of left ventricular size with regional right ventricular mechanics in Hypoplastic Left Heart Syndrome

BACKGROUND

In Hypoplastic Left Heart Syndrome (HLHS), RV dysfunction is associated with poor outcomes. However, the effect of varying LV size on regional RV mechanics and outcome has not been studied.

METHODS

Twenty newborns (0-7 days) with HLHS had pre-stage 1 and pre-stage 2 echocardiograms prospectively protocoled for strain analysis of the apical 4-chamber view. RV longitudinal strain was analyzed, and LV size was classified as diminutive (no visible LV chamber) or moderate size (visible LV chamber). Clinical outcome was reported as alive vs death or transplant (D-TP) at final clinical follow-up (pre-stage 3). Groups were compared with t-test, Fisher's Exact, and ANOVA tests as appropriate.

RESULTS

At pre-stage 1, infants with a diminutive LV (7/20, 35%) vs a moderately hypoplastic LV (13/20, 65%) did not have significantly different global RV strain (-18.4 ± 2.6% vs -18.8 ± 3.2%; p = 0.83). However, basal septal strain was significantly diminished in the moderately hypoplastic LV group vs the diminutive LV group (-4.4 ± 6.0% vs -14.7 ± 3.3%; p < 0.005). There was severely diminished septal strain in nearly all (11/13) of the moderately hypoplastic group. At the pre-stage II echo, global RV strain between groups remained similar (p = 0.76) as did the diminished septal strain in the moderate LV group (p = 0.86). The moderately hypoplastic LV group had worse clinical outcomes (6/13 D-TP vs 0/7 D-TP; p = 0.05).

CONCLUSIONS

In this small HLHS cohort, diminished septal strain leading to asymmetric RV mechanics may be associated with poor outcomes in those with larger LV/septal size.

Accuracy and reliability of qualitative echocardiography assessment of right ventricular size and function in neonates

BACKGROUND

Subjective assessment of right ventricular (RV) function by neonatal echocardiography lacks validation. Incorrect diagnostic assignment in patients with suspected pulmonary hypertension (PH) may lead to unnecessary treatment or missed treatment opportunities.

METHODS

Six evaluators (experts [n = 3], novice [n = 3]) were asked to independently rate RV characteristics (global function, dilation, and septal flattening) based on standardized echocardiography images. We randomly selected 60 infants, ≥35 weeks gestation at birth, of whom 30 were clinically unwell with acute pulmonary hypertension (aPH) and 30 were healthy controls. aPH was defined by echocardiography presence of right-left shunting across transitional shunts or elevated right ventricular systolic pressure as estimated by the magnitude of the regurgitant jet across the tricuspid valve with impaired oxygenation. Inter-rater comparative evaluation within groups and between groups was performed using Kappa statistics.

RESULTS

Global agreement between evaluators for subjective assessment of RV function (0.3 [0.03], P < 0.001), size (0.14 [0.02], P < 0.001), and septal flattening (0.2 [0.02], P < 0.001) was uniformly poor. Agreement in RV function assessment was marginally better for both expert (0.32 [0.08], P < 0.001 vs 0.13 [0.081], and P < 0.001) and novice (0.4 [0.08], P < 0.001 vs 0.06 [0.07], and P < 0.001) evaluators. Overall, the diagnosis of aPH vs control was misclassified in 18% of cases.

CONCLUSION

This study demonstrated significant variability in qualitative assessment of RV size and function by trained evaluators, regardless of level of expertise attained. The reliability of objective measures of RV hemodynamics requires prospective evaluation.

The overlooked left ventricle in persistent pulmonary hypertension of the newborn

Introduction: Persistent pulmonary hypertension of the newborn (PPHN) is a rapidly increasing condition among neonates. It represents failure of adaptation of pulmonary circulation to the extrauterine environment causing severe hypoxemia in affected newborns. Few data have weighed the relationship of ventricular dysfunction in the context of PPHN and the outcome in involved patients. The aim of this paper is to study ventricular functions in newborns with PPHN and to determine whether short-term outcome is closely related or not to ventricular dysfunction occurring in PPHN.Methods: Thirty full-term neonates with PPHN were screened with conventional echocardiography and tissue Doppler imaging (TDI) for the assessment of ventricular functions at the start of treatment for PPHN, demographic data and Arterial blood gazes were performed as well. The echocardiographic data were compared to healthy age-matched controls. The sensitivity and specificity of relevant echocardiographic data to predict the short-term (Day 3) outcome of patients were measured.Results: Patients with PPHN had both left ventricular (LV) and right ventricular (RV) dysfunction when compared to controls, RV Tei (Cases: 0.39 ± 0.1 versus controls: 0.29 ± 0.08, p < .01) LV Tei (Cases: 0.3 ± 0.04 versus controls: 0.25 ± 0.02, p < .01), LV functions were found of greatest prediction of negative outcome in cases with PPHN than RV Tei.Conclusion: The aforementioned findings are sight opening towards the importance of LV dysfunction in PPHN, LV dysfunction might occur in PPHN as a result of RV-LV interactions and the observed involvement might be an important aggravating factor of PPHN.

Prognostic utility of noninvasive estimates of pulmonary vascular compliance in neonates with congenital diaphragmatic hernia

AIM

To evaluate echocardiographic indices of pulmonary vascular resistance and right ventricular (RV) function in predicting death or ECMO in congenital diaphragmatic hernia (CDH).

METHODS

In this single center study, early (<48 h) echocardiograms of neonates with CDH (n = 47) were reviewed by a single reader for the ratio of tricuspid regurgitant velocity to velocity time integral at the pulmonary valve (TRV/VTIpv), TRV2/VTIpv, RV fractional area change (FAC) and tricuspid annular plane systolic excursion (TAPSE). Receiver operating characteristic curves were generated for each parameter to obtain optimal cutoff values.

RESULTS

Infants who died or received ECMO (n = 30) had significantly higher TRV/VTIpv and TRV2/VTIpv, and lower VTIpv, RV FAC and TAPSE, compared to the 17 survivors without ECMO. For TRV2/VTIpv and TRV/VTI at cutoffs of 1.3 and 0.38 respectively, the sensitivities were 92.3 (95% CI 75-99.1%) and 96 (95% CI 80.4-99.9%), specificities were 78.6 (49.2-95.4%) and 71.4 (42-91.6%), positive predictive values were 89 (75-95.6%) and 86.2 (73.2-93.5%) and negative predictive values were 84.6 (58.5-95.5%) and 90.9 (58.7-98.6%).

CONCLUSION

Early echocardiographic evidence of pulmonary hypertension and RV dysfunction predicts outcome in CDH. Further studies utilizing these indices to guide therapeutic decision-making are warranted.

LEVEL OF EVIDENCE

Level 1 for diagnostic study.

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.

Preterm growth restriction and bronchopulmonary dysplasia: the vascular hypothesis and related physiology

KEY POINTS

Approximately 5-10% pregnancies are affected by fetal growth restriction. Preterm infants affected by fetal growth restriction have a higher incidence of bronchopulmonary dysplasia. The present study is the first to measure pulmonary artery thickness and stiffness. The findings show that impaired vasculogenesis may be a contributory factor in the higher incidence of bronchopulmonary dysplasia in preterm growth restricted infants. The study addresses the mechanistic link between fetal programming and vascular architecture and mechanics.

ABSTRACT

Bronchopulmonary dysplasia is the most common respiratory sequelae of prematurity and histopathologically features fewer, dysmorphic pulmonary arteries. The present study aimed to characterize pulmonary artery mechanics and cardiac function in preterm infants with fetal growth restriction (FGR) compared to those appropriate for gestational age (AGA) in the early neonatal period. This prospective study reviewed 40 preterm infants between 28 to 32 weeks gestational age (GA). Twenty infants had a birthweight <10th centile and were compared with 20 preterm AGA infants. A single high resolution echocardiogram was performed to measure right pulmonary arterial and right ventricular (RV) indices. The GA and birthweight of FGR and AGA infants were 29.8 ± 1.3 vs. 30 ± 0.9 weeks (P = 0.78) and 923.4 g ± 168 vs. 1403 g ± 237 (P < 0.001), respectively. Assessments were made at 10.5 ± 1.3 days after birth. The FGR infants had significantly thicker right pulmonary artery inferior wall (843.5 ± 68 vs. 761 ± 40 μm, P < 0.001) with reduced pulsatility (51.6 ± 7.6 μm vs. 59.7 ± 7.5 μm, P = 0.001). The RV contractility [fractional area change (28.7 ± 3.8% vs 32.5 ± 3.1%, P = 0.001), tricuspid annular peak systolic excursion (TAPSE) (5.2 ± 0.3% vs. 5.9 ± 0.7%, P = 0.0002) and myocardial performance index (0.35 ± 0.03 vs. 0.28 ± 0.02, P < 0.001)] was significantly impaired in FGR infants. Significant correlation between RV longitudinal contractility (TAPSE) and time to peak velocity/RV ejection time (measure of RV afterload) was noted (r²  =  0.5, P < 0.001). Altered pulmonary vascular mechanics and cardiac performance reflect maladaptive changes in response to utero-placental insufficiency. Whether managing pulmonary vascular disease will alter clinical outcomes remains to be studied prospectively.

Application of Neonatologist Performed Echocardiography in the assessment and management of persistent pulmonary hypertension of the newborn

Pulmonary hypertension contributes to morbidity and mortality in both the term newborn infant, referred to as persistent pulmonary hypertension of the newborn (PPHN), and the premature infant, in the setting of abnormal pulmonary vasculature development and arrested growth. In the term infant, PPHN is characterized by the failure of the physiological postnatal decrease in pulmonary vascular resistance that results in impaired oxygenation, right ventricular failure, and pulmonary-to-systemic shunting. The pulmonary vasculature is either maladapted, maldeveloped, or underdeveloped. In the premature infant, the mechanisms are similar in that the early onset pulmonary hypertension (PH) is due to pulmonary vascular immaturity and its underdevelopment, while late onset PH is due to the maladaptation of the pulmonary circulation that is seen with severe bronchopulmonary dysplasia. This may lead to cor-pulmonale if left undiagnosed and untreated. Neonatologist performed echocardiography (NPE) should be considered in any preterm or term neonate that presents with risk factors suggesting PPHN. In this review, we discuss the risk factors for PPHN in term and preterm infants, the etiologies, and the pathophysiological mechanisms as they relate to growth and development of the pulmonary vasculature. We explore the applications of NPE techniques that aid in the correct diagnostic and pathophysiological assessment of the most common neonatal etiologies of PPHN and provide guidelines for using these techniques to optimize the management of the neonate with PPHN.

Tissue Doppler velocity imaging and event timings in neonates: a guide to image acquisition, measurement, interpretation, and reference values

Neonatologists can use echocardiography for real-time assessment of the hemodynamic state of neonates to support clinical decision-making. There is a large body of evidence showing the shortcomings of conventional echocardiographic indices in neonates. Newer imaging modalities have evolved. Tissue Doppler imaging is a new technique that can provide measurements of myocardial movement and timing of myocardial events and may overcome some of the shortcomings of conventional techniques. The high time resolution and its ability to assess left and right cardiac function make tissue Doppler a favorable technique for assessing heart function in neonates. The aim of this review is to provide an up-to-date overview of tissue Doppler techniques for the assessment of cardiac function in the neonatal context, with focus on measurements from the atrioventricular (AV) plane. We discuss basic concepts, protocol for assessment, feasibility, and limitations, and we report reference values and give examples of its use in neonates.

Controversies in the identification and management of acute pulmonary hypertension in preterm neonates

It is increasingly recognized that the abnormal physiologic consequences of pulmonary hypertension (PH) may contribute to poor cardiopulmonary health in premature babies. Conflicting literature has led to clinical uncertainty, pathological misinterpretation, and variability in treatment approaches among practitioners. There are several disorders with overlapping and interrelated presentations, and other disorders with a similar clinical phenotype but diverse pathophysiological contributors. In this review, we provide a diagnostic approach for acute hypoxemic respiratory failure in the preterm neonate, outline the pathophysiological conditions that may present as acute PH, and discuss the implications of high pulmonary vascular resistance (PVR) on the cardiovascular system. Although PVR and respiratory management are highly interrelated, there may be a population of preterm neonates in whom inhaled nitric oxide may improve illness severity and may relate to outcomes. A management approach based on physiology that considers common clinical conundrums is provided. A more comprehensive understanding of the physiology may help in informed decision-making in clinical situations where conclusive scientific evidence is lacking. Regardless, high-quality research is required, and appropriate definition of the target population is paramount. A thoughtful approach to cardiovascular therapy may also provide an avenue to improve neurodevelopmental outcomes while awaiting more clear answers.

Assessing Myocardial Function in Infants with Pulmonary Hypertension: The Role of Tissue Doppler Imaging and Tricuspid Annular Plane Systolic Excursion

Transthoracic echocardiography is the most common noninvasive method of evaluating pulmonary hypertension (PH) in infants. Identification of reliable, quantitative indices of myocardial function may enhance the diagnostic value of echocardiography in this population. We hypothesized that pulsed wave tissue Doppler imaging (TDI) and tricuspid annular plane systolic excursion (TAPSE) would be reproducible measurements and would suggest decreased ventricular function, in infants with PH. This retrospective case-control study involved subjects diagnosed clinically and echocardiographically with PH at <12 months of age, matched with controls by age and gestational age (GA). TAPSE was measured by M-mode in the apical 4-chamber view. TDI velocities were averaged from three consecutive cardiac cycles. Observers were blinded to patient identity and clinical status. Fifty-seven subjects, including 35 term or near-term infants ≥35 weeks GA [mean GA 39 weeks (±1.7), median age 1 day (range 0-2)] and 22 preterm infants [median GA 25.4 weeks (24.1-26.6), age 66 days (4-128)], were matched with 57 controls. Subjects with PH had lower TAPSE (term p < 0.001, preterm p = 0.03) and TAPSE indexed to body surface area (term p < 0.001, preterm p = 0.005). Mitral annular, septal, and tricuspid annular systolic (S') and early diastolic (E') TDI velocities were also decreased compared to controls (all p < 0.05). Intraclass correlation demonstrated 84-99% agreement between observers in measuring TDI and 92% for TAPSE. Intraobserver reliability for these measures was 98-99% and 96%, respectively. We concluded that TDI and TAPSE are reproducible indices of myocardial function and may serve as useful adjuncts to standard echocardiographic measures in infants with PH.

Echocardiographic Evaluation of Hemodynamics in Neonates and Children

Hemodynamic instability and inadequate cardiac performance are common in critically ill children. The clinical assessment of hemodynamic status is reliant upon physical examination supported by the clinical signs such as heart rate, blood pressure, capillary refill time, and measurement of the urine output and serum lactate. Unfortunately, all of these parameters are surrogate markers of cardiovascular well-being and they provide limited direct information regarding the adequacy of blood flow and tissue perfusion. A bedside point-of-care echocardiography can provide real-time hemodynamic information by assessing cardiac function, loading conditions (preload and afterload) and cardiac output. The echocardiography has the ability to provide longitudinal functional assessment in real time, which makes it an ideal tool for monitoring hemodynamic assessment in neonates and children. It is indispensable in the management of patients with shock, pulmonary hypertension, and patent ductus arteriosus. The echocardiography is the gold standard diagnostic tool to assess hemodynamic stability in patients with pericardial effusion, cardiac tamponade, and cardiac abnormalities such as congenital heart defects or valvar disorders. The information from echocardiography can be used to provide targeted treatment in intensive care settings such as need of fluid resuscitation versus inotropic support, choosing appropriate inotrope or vasopressor, and in providing specific interventions such as selective pulmonary vasodilators in pulmonary hypertension. The physiological information gathered from echocardiography may help in making timely, accurate, and appropriate diagnosis and providing specific treatment in sick patients. There is no surprise that use of bedside point-of-care echocardiography is rapidly gaining interest among neonatologists and intensivists, and it is now being used in clinical decision making for patients with hemodynamic instability. Like any other investigation, it has certain limitations and the most important limitation is its intermittent nature. Sometimes acquiring high quality images for precise functional assessment in a ventilated child can be challenging. Therefore, it should be used in conjunction with the existing tools (physical examination and clinical parameters) for hemodynamic assessment while making clinical decisions.

An international survey on persistent pulmonary hypertension of the newborn: A need for an evidence-based management

OBJECTIVE

To assess the current practice preferences in diagnosis and management of persistent hypertension of the newborn (PPHN) of neonatologists or pediatricians with expertise in neonatal care.

STUDY DESIGN

Investigators identified potential participants worldwide through a literature search. They were emailed the URL of an online 25-item questionnaire through the web survey site SurveyMonkey®. Additional respondents were also acquired through a professional online discussion group. The survey was conducted during July - September 2015.

RESULTS

Overall, there were 200 respondents from 51 different countries. Of these, the average 2014 mortality rate of the 90 respondents who completed this section of the questionnaire was 8.3% (interquartile range (IQR): 0-20.3). Echocardiography together with pre-to-post ductal oxygen pulse oximetry (SpO2) gradient was the most common PPHN diagnostic method. The most frequent first-line pulmonary vasodilator was inhaled nitric oxide (155/199, 77.9%). Oral sildenafil was most commonly used as second-line adjunctive therapy by 46.3% (81/175). Dopamine (139/198, 70.2%) was chosen to be the initial inotropic agent and normal saline (191/199, 96.0%) was the preferred initial fluid resuscitation for hypotension. Sedation and analgesia were routinely used for PPHN treatment. Twenty-one percent (42/199) of respondents also used muscle relaxants to control respiratory distress. The most commonly used targets for partial pressure of oxygen, partial pressure of carbon dioxide, SpO2 and hemoglobin were 71-80 mmHg (60/197, 30.4%), 36-45 mmHg (100/199, 50.2%), 91-95% (111/199, 55.8%), and 13-15 gm/dL (156/196, 79.6%), respectively.

CONCLUSIONS

This survey shows that the management of PPHN varies widely around the world. The major PPHN diagnostic method is echocardiography together with bedside SpO2 monitoring. The study numbers show the main differences are between developed and developing countries. Further studies exploring evidence-based principles of diagnosis and management in PPHN are warranted.