Echocardiographic evaluation of right ventricular function in preterm infants with bronchopulmonary dysplasia

Characterizing the Role of Left Ventricular Indices and Biventricular Interaction in Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension in Extreme Prematurity

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is a common respiratory morbidity in preterm infants. The onset of pulmonary hypertension leads to worse respiratory outcomes. The contribution of left ventricular diastolic dysfunction in BPD-PH is well reported. We evaluated the serial left ventricular function and possible ventricular interdependence among BPD-PH.

METHODS

This is a single-center, prospective observational study. Infants <28 weeks of gestation are included.

RESULTS

Eighty infants were enrolled. The incidence of BPD-PH was 23%. The BPD-PH group had a high incidence of hemodynamically significant ductus arteriosus (83% vs. 56%, p < 0.018), longer oxygen days (96.2 ± 68.1 vs. 59.35 ± 52, p < 0.008), and prolonged hospital stay (133.8 ± 46 vs. 106.5 ± 38 days, p < 0.005). Serial tissue Doppler imaging showed prolonged left ventricle (LV) isovolumetric contraction time (IVCT) (31.05 ± 3.3 vs. 26.8 ± 4.4 ms, p < 0.001) and myocardial performance index (MPI) (0.43 ± 0.03 vs. 0.37 ± 0.04, p < 0.001) from 33 weeks. The changes in IVCT (35.9 ± 6.7 vs. 27.9 ± 4.5 ms, p < 0.001), isovolumetric relaxation time (IVRT) (50 ± 6.5 vs. 39.9 ± 5.8 ms, p < 0.001), and MPI (0.48 ± 0.05 vs. 0.36 ± 0.03, p < 0.001) persisted at 36 weeks. The receiver operator characteristic curve showed LV MPI >40 has 83% sensitivity and 65% specificity (AUC: 0.77, p < 0.001) in the diagnosis of PH. The BPD-PH group had a higher LV E/E' ratio (13.1 ± 4.4 vs. 11.4 ± 3.4, p < 0.02). Pearson correlation test showed a moderate positive correlation between RV MPI and LV MPI (r = 0.585, p < 0.001).

CONCLUSIONS

Significant LV diastolic dysfunction was observed in BPD-PH. This is the first study to show biventricular strain and possible ventricular interdependence in BPD-PH. The prolonged LV IVRT and MPI may be a novel echocardiographic indicator of BPD-PH.

Improving early diagnosis of bronchopulmonary dysplasia

INTRODUCTION

Bronchopulmonary disease (BPD) is associated with long-term neurodevelopmental and cardiorespiratory complications, often requiring significant use of resources. To reduce this healthcare burden, it is essential that those at high risk of BPD are identified early so that strategies are introduced to prevent disease progression. Our aim was to discuss potential methods for improving early diagnosis in the first week after birth.

AREAS COVERED

A narrative review was undertaken. The search strategy involved searching PubMed, Embase and Cochrane databases from 1967 to 2024. The results of potential biomarkers and imaging modes are discussed. Furthermore, the value of scoring systems is explored.

EXPERT OPINION

BPD occurs as a result of disruption to pulmonary vascular and alveolar development, thus abnormal levels of factors regulating those processes are promising avenues to explore with regard to early detection of high-risk infants. Data from twin studies suggests genetic factors can be attributed to 82% of the observed difference in moderate to severe BPD, but large genome-wide studies have yielded conflicting results. Comparative studies are required to determine which biomarker or imaging mode may most accurately diagnose early BPD development. Models which include the most predictive factors should be evaluated going forward.

Echocardiography parameters used in identifying right ventricle dysfunction in preterm infants with early bronchopulmonary dysplasia: A scoping review

Background

Bronchopulmonary Dysplasia (BPD) is a chronic condition that affects preterm infants and is associated with long-term complications. Haemodynamic effects of BPD can lead to right ventricular (RV) dysfunction.

Objective

To synthesise and map the evidence of echo parameters used in identifying RV dysfunction in the first two weeks-after-birth (WAB) of preterm infants with early BPD.

Information Sources

This scoping review included the databases: Medline, CINAHL, PubMed, EMBASE, Scopus, ProQuest, Web of Science, Cochrane Library, JBI Evidence-Based Practise and Gray Literature.

Search Strategy

The search utilised Boolean operators and descriptors registered in Medical Subject Headings.

Inclusion and exclusion criteria

Included were studies utilising echo parameters to examine RV function in preterm infants with early BPD in the first two WAB.

Synthesis of results

The results are presented as a map of the extracted findings in a tabular format with a narrative summary.

Results

Eight studies were included. Differences were observed in the number and timing of echo scans performed in the first two WAB and the variations in the echo parameters used to compare preterm infants with and without early BPD. Only echo scans performed at the end of the first WAB, demonstrated significant differences in the echo parameters measurements between preterm infants with and without BPD. Studies using RV Myocardial Performance Index (MPI) to identify RV-dysfunction associated with early BPD demonstrated similar findings. The Pulsed-Wave Doppler technique identified differences in RV-MPI between preterm infants with and without BPD, while Tissue-Doppler-Imaging did not demonstrate similar results. Speckle tracking can measure strain (S) and strain rate (SR) and diagnose RV-dysfunction. However, the findings of studies that utilised speckle tracking varied. Finally, two of the included studies added blood tests to their diagnostic model of early BPD, which was able to demonstrate significant differences in blood test results between BPD-affected and control preterm infants.

Conclusion

BPD could adversely affect the myocardium function of the RV; these negative influences can be captured in the first two WAB. However, there are still knowledge gaps regarding the appropriate number, timing and the most suitable echo parameters to assess RV function.

A scoping review of echocardiographic and lung ultrasound biomarkers of bronchopulmonary dysplasia in preterm infants

Despite recent improvements in neonatal care, moderate to severe bronchopulmonary dysplasia (BPD) is still associated with high mortality and with an increased risk of developing pulmonary hypertension (PH). This scoping review provides an updated overview of echocardiographic and lung ultrasound biomarkers associated with BPD and PH, and the parameters that may prognosticate their development and severity, which could be clinically helpful to undertake preventive strategies. A literature search for published clinical studies was conducted in PubMed using MeSH terms, free-text words, and their combinations obtained through appropriate Boolean operators. It was found that the echocardiography biomarkers for BPD, and especially those assessing right ventricular function, are reflective of the high pulmonary vascular resistance and PH, indicating a strong interplay between heart and lung pathophysiology; however, early assessment (e.g., during the first 1-2 weeks of life) may not successfully predict later BPD development. Lung ultrasound indicating poor lung aeration at day 7 after birth has been reported to be highly predictive of later development of BPD at 36 weeks' postmenstrual age. Evidence of PH in BPD infants increases risk of mortality and long-term PH; hence, routine PH surveillance in all at risk preterm infants at 36 weeks, including an echocardiographic assessment, may provide useful information. Progress has been made in identifying the echocardiographic parameters on day 7 and 14 to predict later development of pulmonary hypertension. More studies on sonographic markers, and especially on echocardiographic parameters, are needed for the validation of the currently proposed parameters and the timing of assessment before recommendations can be made for the routine clinical practice.

Echocardiographic and ultrasound evaluation of haemodynamic parameters in hypoxic neonates treated with hypothermia: Study protocol

Background

Episodes of ischaemia-hypoxia in the perinatal period as well as the changes in the redistribution of blood may lead to decreased perfusion and ischaemia of the cardiac muscle. Additionally, there is a negative impact from the reduced contractility of the cardiac muscle secondary to acidosis and hypoxia. Therapeutic hypothermia (TH) improves the late effects in moderate and severe cases of hypoxia-ischaemia encephalopathy (HIE). The direct impact of TH on the cardiovascular system includes moderate bradycardia, increased pulmonary vascular resistance (PVR), inferior filling of the left ventricle (LV) and LV stroke volume. The above-mentioned consequences of TH and episodes of HI in the perinatal period are therefore exacerbation of respiratory and circulatory failure. The impact of the warming phase on the cardiovascular system is not well researched and currently few data has been published on this topic. Physiologically, warming increases heart rate, improves cardiac output and increases systemic pressure. The effect of TH and the warming phase on the cardiovascular values has a decisive impact on the metabolism of drugs, including vasopressors/inotropics, which in turn affects the choice of medication and fluid therapy.

Method

The study is a multi-centre, prospective, case-control, observational study. The study will include 100 neonates (50 subjects and 50 controls). Echocardiography and cerebral and abdominal ultrasound will be performed in the first 1/2 days after birth as well as during warming i.e., on day 4/7 of life. In neonatal controls these examinations will be performed for indications other than hypothermia, most frequently because of poor adaptation.

Ethics and dissemination

The Ethics Committee of the Medical University of Warsaw approved the study protocol prior to recruitment (KB 55/2021). Informed consent will be obtained from the carers of the neonates at the time of enrolment. Consent for participation in the study can be withdrawn at any time, without consequences and without obligation to justify the decision. All data will be stored in a secure, password-protected Excel file that is only accessible to researchers involved in the study. Findings will be published in a peer-reviewed journal and disseminated at relevant national and international conferences.

Clinical Trial Registration

NCT05574855.

The association between pulmonary vascular disease and respiratory improvement in infants with type I severe bronchopulmonary dysplasia

OBJECTIVE

To describe the association between echocardiographic measures of pulmonary vascular disease and time to respiratory improvement among infants with Type I severe bronchopulmonary dysplasia (sBPD).

STUDY DESIGN

We measured the pulmonary artery acceleration time indexed to the right ventricular ejection time (PAAT/RVET) and right ventricular free wall longitudinal strain (RVFWLS) at 34-41 weeks' postmenstrual age. Cox-proportional hazards models were used to estimate the relationship between the PAAT/RVET, RVFWLS, and the outcome: days from 36 weeks' postmenstrual age to room-air or discharge with oxygen (≤0.5 L/min).

RESULT

For 102 infants, the mean PAAT/RVET and RVFWLS were 0.27 ± 0.06 and -22.63 ± 4.23%. An abnormal measurement was associated with an increased time to achieve the outcome (PAAT/RVET: 51v24, p < 0.0001; RVFWLS; 62v38, p = 0.0006). A normal PAAT/RVET was independently associated with a shorter time to outcome (aHR = 2.04, 1.11-3.76, p = 0.02).

CONCLUSION

The PAAT/RVET may aid in anticipating timing of discharge in patients with type I severe BPD.

Cardiovascular impact and sequelae of bronchopulmonary dysplasia

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

Influence of extreme prematurity and bronchopulmonary dysplasia on cardiac function

OBJECTIVE

Prematurity and bronchopulmonary dysplasia (BPD) are associated with poorly understood abnormalities of ventricular function. We therefore comprehensively compared biventricular function in infants with and without BPD.

METHODS

Prospective observational study in extremely preterm infants with (n = 20) and without (n = 38) BPD using conventional and advanced echocardiography at 28 days (T1) and near-term (T2).

RESULTS

Infants with BPD had lower birth gestational age (26.7±1.9 vs 27.4±1.1 weeks, p = 0.047) and weight (884±207 vs 1108±190 g, p = 0.0001). BPD was associated with larger right ventricles (RV) and reduced RV systolic strain rate at T1 and pulmonary hypertensive indicators at T2 (pulmonary artery acceleration time BPD 51±17 vs no BPD 63±12 ms, p = 0.017). At T1/T2, infants with BPD had lower RV tissue Doppler velocities (e', a' and s) and higher E/e' ratios (T1: BPD 10.4±2.4 vs no BPD 6.2±3.1 cm/sec, p = 0.001; T2: BPD 8.0±3.1 vs no BPD 5.6±2.6 cm/sec, p = 0.02), altered LV diastolic function (apical circumferential T1 early diastolic strain rate BPD 2.8±0.8 vs no BPD 3.6±1.0 /sec, p = 0.04; T2 late diastolic strain rate, BPD 2.29 ± 0.99 vs no BPD 1.67±0.84 /sec, p = 0.03) and LV rotational mechanics (T1: twist rate BPD 90±16 vs no BPD 130±48 deg/sec^, p = 0.008; untwist rate (UTR) BPD -69±90 vs no BPD -147±68 deg/sec, p = 0.008; torsion BPD 2.78±0.56 vs no BPD 4.48±1.74 deg/cm, p = 0.009; and T2: UTR BPD -132±69 vs no BPD -179±57 deg/sec, p = 0.013).

CONCLUSION

BPD is associated with altered RV diastolic function that persists near term, with elevated pulmonary vascular resistance, and with persistent alterations in LV apical strain rate and rotational mechanics.

Echocardiographic Monitoring of Cardiac Parameters to Predict Bronchial Dysplasia in Very Premature Infants

Echocardiography was used to measure the cardiac parameters in high-risk premature infants prone to bronchopulmonary dysplasia (BPD). These measurements were used to determine the correlation between the parameters and BPD and whether they could be used to predict the parameters associated with cardiac health of BPD in very premature infants at a very early stage. Seventy-four very premature infants (gestational age < 32 weeks) were recruited in this retrospective, single-center, observational studies. All infants were examined using echocardiography within a week after birth, and the cardiac chamber parameters were recorded. Of these, 14 infants with BPD were reexamined at 4 weeks after birth. Statistical analysis and comparison of the data of these 14 infants indicated that 1-week after birth, the inner diameters of PA/AS/AO/LA/ROVT/LVPW/LV were significantly smaller (P < 0.05), and that of AS/AO/LA/LV were highly significantly smaller (P < 0.001) in the BPD group compared with the non-BPD group. Comparing the cardiac parameters between 1 and 4 weeks after birth in infants with BPD showed a significant difference in the diameter of PA/AS/AO/ROVT/IVS/LVPW/LV, suggesting that the ventricular cavity developed more efficiently during growth.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early Pulmonary Vascular Disease in Preterm Infants Is Associated with Late Respiratory Outcomes in Childhood

RATIONALE

Early pulmonary vascular disease (PVD) after preterm birth is associated with a high risk for developing bronchopulmonary dysplasia (BPD), but its relationship with late respiratory outcomes during early childhood remains uncertain.

OBJECTIVES

To determine whether PVD at 7 days after preterm birth is associated with late respiratory disease (LRD) during early childhood.

METHODS

This was a prospective study of preterm infants born before 34 weeks postmenstrual age (PMA). Echocardiograms were performed at 7 days and 36 weeks PMA. Prenatal and early postnatal factors and postdischarge follow-up survey data obtained at 6, 12, 18, and 24 months of age were analyzed in logistic regression models to identify early risk factors for LRD, defined as a physician diagnosis of asthma, reactive airways disease, BPD exacerbation, bronchiolitis, or pneumonia, or a respiratory-related hospitalization during follow-up.

MEASUREMENTS AND MAIN RESULTS

Of the 221 subjects (median, 27 wk PMA; interquartile range, 25-28 and 920 g; interquartile range, 770-1090 g) completing follow-up, 61% met LRD criteria. Gestational diabetes and both mechanical ventilator support and PVD at 7 days were associated with LRD. The combination of PVD and mechanical ventilator support at 7 days was among the strongest prognosticators of LRD (odds ratio, 8.1; confidence interval, 3.1-21.9; P < 0.001). Modeled prenatal and early postnatal factors accurately informed LRD (area under the curve, 0.764). Adding BPD status at 36 weeks PMA to the model did not change the accuracy (area under the curve, 0.771).

CONCLUSIONS

Early echocardiographic evidence of PVD after preterm birth in combination with other perinatal factors is a strong risk factor for LRD, suggesting that early PVD may contribute to the pathobiology of BPD.

Myocardial Function Maturation in Very-Low-Birth-Weight Infants and Development of Bronchopulmonary Dysplasia

Background: Myocardial function in very-low-birth-weight infants (VLBWIs) develops during early postnatal life, but different patterns of temporal evolution that might be related to the development of bronchopulmonary dysplasia (BPD) are not completely understood. Methods: A prospective cohort study including VLBWIs admitted to our NICU from January 2015 to 2017 was conducted. Plasma N-terminal pro B type natriuretic peptide (NTproBNP) levels were measured, and echocardiograms were performed at 24 and 72 h of life and weekly thereafter until 36 weeks of postmenstrual age (PMA). We measured the tricuspid annular plane systolic excursion (TAPSE) by M-mode; the lateral tricuspid E', A', and S' waves; and the myocardial performance index (MPI) by tissue doppler imaging (TDI). The subjects were divided into non-BPD and BPD groups. Results: We included 101 VLBWIs. The TAPSE and E', A', and S' waves increased while MPI-TDI decreased over time. Birth gestational age (GA) and postnatal PMA impacted these parameters, which evolved differently in those who developed BPD compared to those in the non-BPD group. The NTproBNP levels at 14 days of life and different echocardiographic parameters were associated with the development of BPD in different multivariate models. Conclusion: TAPSE and TDI values depend on GA and PMA and follow a different temporal evolution that is related to the later development of BPD. Combined biochemical and echocardiographic biomarkers can help identify which VLBWIs are at higher risk of developing BDP.

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.