Reliability of Echocardiographic Indicators of Pulmonary Vascular Disease in Preterm Infants at Risk for Bronchopulmonary Dysplasia

Clinical journey for patients with aortic regurgitation: A retrospective observational study from a multicenter database

BACKGROUND

Data using real-world assessments of aortic regurgitation (AR) severity to identify rates of Heart Valve Team evaluation and aortic valve replacement (AVR), as well as mortality among untreated patients, are lacking. The present study assessed these trends in care and outcomes for real-world patients with documented AR.

METHODS

Using a deidentified data set (January 2018-March 2023) representing 1,002,853 patients >18 years of age from 25 US institutions participating in the egnite Database (egnite, Inc.) with appropriate permissions, patients were classified by AR severity in echocardiographic reports. Rates of evaluation by the Heart Valve Team, AVR, and all-cause mortality without AVR were examined using Kaplan-Meier estimates and compared using the log-rank test.

RESULTS

Within the data set, 845,113 patients had AR severity documented. For moderate-to-severe or severe AR, respectively, 2-year rates (95% confidence interval) of evaluation by the Heart Valve Team (43.5% [41.7%-45.3%] and 65.4% [63.3%-67.4%]) and AVR (19.4% [17.6%-21.1%] and 46.5% [44.2%-48.8%]) were low. Mortality at 2 years without AVR increased with greater AR severity, up to 20.7% for severe AR (p < 0.001). In exploratory analyses, 2-year mortality for untreated patients with left ventricular end-systolic dimension index > 25 mm/m2 was similar for moderate (34.3% [29.2%-39.1%]) and severe (37.2% [24.9%-47.5%]) AR.

CONCLUSIONS

Moderate or greater AR is associated with poor clinical outcomes among untreated patients at 2 years. Rates of Heart Valve Team evaluation and AVR were low for those with moderate or greater AR, suggesting that earlier referral to the Heart Valve Team could be beneficial.

Pulmonary Hypertension and Necrotizing Enterocolitis in Neonates Treated with Diazoxide

OBJECTIVE

This study aimed to evaluate the prevalence of adverse outcomes, specifically pulmonary hypertension (PH) and suspected or confirmed necrotizing enterocolitis (NEC), and their associated risk factors, in neonates treated with diazoxide.

STUDY DESIGN

A retrospective study in infants born ≥ 316/7 weeks and admitted between January 2014 and June 2020. Combined adverse outcomes possibly associated to diazoxide were PH (systolic pulmonary pressure of ≥40 mm Hg or an eccentricity index ≥1.3) and suspected or confirmed NEC (suspected: stop feeds and antibiotics and confirmed: modified Bell stage ≥2). Echocardiography data extractors were masked to infants' characteristics.

RESULTS

A total of 63 infants were included; 7 (11%) with suspected and 1 (2%) with confirmed NEC. Of the 36 infants with an available echocardiography after initiation of diazoxide treatment, 12 (33%) had PH. All infants with suspected or confirmed NEC were males (p = 0.01), whereas PH occurred mostly in females (75%, p = 0.02). The combined adverse outcome occurred in 14/26 (54%) infants exposed to >10 mg/kg/day, compared to 6/37 (16%) exposed to ≤10 mg/kg/day (p = 0.006). This association remained significant after adjustment for sex, small for gestational age status, and gestational age at birth (odds ratio: 6.1, 95% confidence interval: 1.7-21.7, p = 0.005). Left ventricular dysfunction was found in 19 infants (30%) but was not discriminative for the combined outcome.

CONCLUSION

PH and suspected or confirmed NEC were identified frequently in neonates treated with diazoxide. A total dose >10 mg/kg/day was associated with an increased occurrence of these complications.

KEY POINTS

· PH and suspected or confirmed NEC were frequently found in neonates treated with diazoxide.. · A total dose >10 mg/kg/day was associated with an increased occurrence of these complications.. · Echocardiography screening should be considered in neonates exposed to diazoxide..

Delineating morbidity patterns in preterm infants at near-term age using a data-driven approach

BACKGROUND

Long-term survival after premature birth is significantly determined by development of morbidities, primarily affecting the cardio-respiratory or central nervous system. Existing studies are limited to pairwise morbidity associations, thereby lacking a holistic understanding of morbidity co-occurrence and respective risk profiles.

METHODS

Our study, for the first time, aimed at delineating and characterizing morbidity profiles at near-term age and investigated the most prevalent morbidities in preterm infants: bronchopulmonary dysplasia (BPD), pulmonary hypertension (PH), mild cardiac defects, perinatal brain pathology and retinopathy of prematurity (ROP). For analysis, we employed two independent, prospective cohorts, comprising a total of 530 very preterm infants: AIRR ("Attention to Infants at Respiratory Risks") and NEuroSIS ("Neonatal European Study of Inhaled Steroids"). Using a data-driven strategy, we successfully characterized morbidity profiles of preterm infants in a stepwise approach and (1) quantified pairwise morbidity correlations, (2) assessed the discriminatory power of BPD (complemented by imaging-based structural and functional lung phenotyping) in relation to these morbidities, (3) investigated collective co-occurrence patterns, and (4) identified infant subgroups who share similar morbidity profiles using machine learning techniques.

RESULTS

First, we showed that, in line with pathophysiologic understanding, BPD and ROP have the highest pairwise correlation, followed by BPD and PH as well as BPD and mild cardiac defects. Second, we revealed that BPD exhibits only limited capacity in discriminating morbidity occurrence, despite its prevalence and clinical indication as a driver of comorbidities. Further, we demonstrated that structural and functional lung phenotyping did not exhibit higher association with morbidity severity than BPD. Lastly, we identified patient clusters that share similar morbidity patterns using machine learning in AIRR (n=6 clusters) and NEuroSIS (n=8 clusters).

CONCLUSIONS

By capturing correlations as well as more complex morbidity relations, we provided a comprehensive characterization of morbidity profiles at discharge, linked to shared disease pathophysiology. Future studies could benefit from identifying risk profiles to thereby develop personalized monitoring strategies.

TRIAL REGISTRATION

AIRR: DRKS.de, DRKS00004600, 28/01/2013. NEuroSIS: ClinicalTrials.gov, NCT01035190, 18/12/2009.

MRI pulmonary artery flow detects lung vascular pathology in preterms with lung disease

BACKGROUND

Pulmonary vascular disease (PVD) affects the majority of preterm neonates with bronchopulmonary dysplasia (BPD) and significantly determines long-term mortality through undetected progression into pulmonary hypertension. Our objectives were to associate characteristics of pulmonary artery (PA) flow and cardiac function with BPD-associated PVD near term using advanced magnetic resonance imaging (MRI) for improved risk stratification.

METHODS

Preterms <32 weeks postmenstrual age (PMA) with/without BPD were clinically monitored including standard echocardiography and prospectively enrolled for 3 T MRI in spontaneous sleep near term (AIRR (Attention to Infants at Respiratory Risks) study). Semi-manual PA flow quantification (phase-contrast MRI; no BPD n=28, mild BPD n=35 and moderate/severe BPD n=25) was complemented by cardiac function assessment (cine MRI).

RESULTS

We identified abnormalities in PA flow and cardiac function, i.e. increased net forward volume right/left ratio, decreased mean relative area change and pathological right end-diastolic volume, to sensitively detect BPD-associated PVD while correcting for PMA (leave-one-out area under the curve 0.88, sensitivity 0.80 and specificity 0.81). We linked these changes to increased right ventricular (RV) afterload (RV-arterial coupling (p=0.02), PA mid-systolic notching (t2; p=0.015) and cardiac index (p=1.67×10-8)) and correlated echocardiographic findings. Identified in moderate/severe BPD, we successfully applied the PA flow model in heterogeneous mild BPD cases, demonstrating strong correlation of PVD probability with indicators of BPD severity, i.e. duration of mechanical ventilation (rs=0.63, p=2.20×10-4) and oxygen supplementation (rs=0.60, p=6.00×10-4).

CONCLUSIONS

Abnormalities in MRI PA flow and cardiac function exhibit significant, synergistic potential to detect BPD-associated PVD, advancing the possibilities of risk-adapted monitoring.

Current diagnosis and treatment practice for pulmonary hypertension in bronchopulmonary dysplasia-A survey study in Germany (PUsH BPD)

Pulmonary hypertension (PH) is the most severe complication in preterm infants with bronchopulmonary dysplasia (BPD) and associated with significant mortality. Diagnostic and treatment strategies, however, still lack standardization. By the use of a survey study (PH in BPD), we assessed clinical practice (diagnosis, treatment, follow-up) in preterm infants with early postnatal persistent pulmonary hypertension of the newborn (PPHN) as well as at risk for or with established BPD-associated PH between 06/2018 and 10/2020 in two-thirds of all German perinatal centers with >70 very low birthweight infants/year including their cardiology departments and outpatient units. Data were analyzed descriptively by measures of locations and distributional shares. In routine postnatal care, clinical presentation and echocardiography were reported as the main diagnostic modalities to screen for PPHN in preterm infants, whereas biomarkers brain natriuretic peptide/N-terminal pro b-type natriuretic peptide were infrequently used. For PPHN treatment, inhaled nitric oxide was used in varying frequency. The majority of participants agreed to prescribe diuretics and steroids (systemic/inhaled) for infants at risk for or with established BPD-associated PH and strongly agreed on recommending respiratory syncytial virus immunization and the use of home monitoring upon discharge. Reported oxygen saturation targets, however, varied in these patients in in- and outpatient care. The survey reveals shared practices in diagnostic and therapeutic strategies for preterms with PPHN and BPD-associated PH in Germany. Future studies are needed to agree on detailed echo parameters and biomarkers to diagnose and monitor disease next to a much-needed agreement on the use of pulmonary vasodilators, steroids, and diuretics as well as target oxygen saturation levels.

Pulmonary hypertension in preterm infants with moderate-to-severe bronchopulmonary dysplasia (BPD)

AIM

To describe clinical characteristics of pulmonary hypertension (PH) associated with moderate to severe BPD (MSBPD) in premature infants born ≤32 weeks gestation.

METHODS

This was a single centre retrospective cohort study, with reanalysis of echocardiographic studies for PH of infants born ≤32 weeks gestation with MSBPD admitted to a tertiary surgical neonatal service.

RESULTS

In total, 268 babies with MSBPD were included in the study. Incidence of BPD-associated PH (BPD-PH) was 12.6% (34), of which 41% infants were observed to have severe PH. On multivariate analysis, need for positive pressure respiratory support at 36 weeks post menstrual age (PMA) was independently associated with PH (p = 0.001; 95% CI 2-13.5) Presence of PH and severity of PH were associated with increased mortality. Of babies with MSBPD-PH, 32% died before discharge from the neonatal unit.

CONCLUSION

Babies with MSBPD and PH are more likely to die before discharge from the neonatal unit. Need for positive pressure respiratory support at 36 weeks PMA is independently associated with PH. Babies with MSBPD with less than severe PH are also associated with increased mortality when compared to babies with MSBPD with no PH.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Imaging in neonatal respiratory disease

The purpose of this review is to describe the current state of the art in clinical imaging for NICU patients, divided into major areas that correspond to likely phenotypes of neonatal respiratory disease: airway abnormalities, parenchymal disease, and pulmonary vascular disease. All common imaging modalities (ultrasound, X-ray, CT, and MRI) are discussed, with an emphasis on modalities that are most relevant to the individual underlying aspects of disease. Some promising aspects of dynamic and functional imaging are included, where there may be future clinical applicability.

PATET ratio by Doppler echocardiography: noninvasive detection of pediatric pulmonary arterial hypertension

Pulmonary artery acceleration time (PAT) and PAT: ejection time (PATET) ratio are echocardiographic measurements of pulmonary arterial hypertension (PAH). These noninvasive quantitative measurements are ideal to follow longitudinally through the clinical course of PAH, especially as it relates to the need for and/or response to treatment. This review article focuses on the current literature of PATET measurement for infants and children as it relates to the shortening of the PATET ratio in PAH. At the same time, further development of PATET as an outcome measure for PAH in preclinical models, particularly mice, such that the field can move forward to human clinical studies that are both safe and effective. Here, we present what is known about PATET in infants and children and discuss what is known in preclinical models with particular emphasis on neonatal mouse models. In both animal models and human disease, PATET allows for longitudinal measurements in the same individual, leading to more precise determinations of disease/model progression and/or response to therapy. IMPACT: PATET ratio is a quantitative measurement by a noninvasive technique, Doppler echocardiography, providing clinicians a more precise/accurate, safe, and longitudinal assessment of pediatric PAH. We present a brief history/state of the art of PATET ratio to predict PAH in adults, children, infants, and fetuses, as well as in small animal models of PAH. In a preliminary study, PATET shortened by 18% during acute hypoxic exposure compared to pre-hypoxia. Studies are needed to establish PATET, especially in mouse models of disease, such as bronchopulmonary, as a routine measure of PAH.

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.

Primary pulmonary vein stenosis among premature infants with single-vessel disease

OBJECTIVES

Describe outcomes among preterm infants diagnosed with single-vessel primary pulmonary vein stenosis (PPVS) initially treated using conservative management (active surveillance with deferral of treatment).

STUDY DESIGN

Retrospective cohort study at a single, tertiary-center (2009-2019) among infants <37 weeks' gestation with single-vessel PPVS. Infants were classified into two categories: disease progression and disease stabilization. Cardiopulmonary outcomes were examined, and a Kaplan-Meier survival analysis performed.

RESULTS

Twenty infants were included. Compared to infants in the stable group (0/10, 0%), all infants in the progressive group had development of at least severe stenosis or atresia (10/10, 100%; P < 0.01). Severe pulmonary hypertension at diagnosis was increased in the progressive (5/10, 50%) versus the stable group (0/10, 0%; P = 0.03). Survival was lower among infants in the progressive than the stable group (log-rank test, P < 0.01).

CONCLUSION

Among preterm infants with single-vessel PPVS, risk stratification may be possible, wherein more targeted, individualized therapies could be applied.

Echocardiography evaluation of bronchopulmonary dysplasia-associated pulmonary hypertension: a retrospective observational cohort study

BACKGROUND

Echocardiography has poor accuracy in grading the severity of pulmonary hypertension (PH) compared to cardiac catheterization. However, the relationship between degree of PH and prognostic outcomes remains uncertain. Our primary objective was to determine whether echocardiogram-assessed PH severity is associated with mortality and hospital readmission in the first year of life.

METHODS

A retrospective cohort study of infants born less than 32 weeks of gestational age with bronchopulmonary dysplasia (BPD) underwent echocardiography was performed. Echocardiograms were performed at 36-38 weeks postmenstrual age. Data during hospitalization and post-discharge collected at 1-year age were analyzed with cox regression models and logistic regression models to identify the association of PH severity with mortality and readmission. Area under curve (AUC) was calculated to examine the accuracy of these models to reflect the likelihood of outcomes.

RESULTS

Fifty-six of 237 (23.6%) infants were diagnosed as PH. Moderate and severe PH was significantly associated with mortality during the first one year of life (moderate PH vs. none HR =26.58, 95% CI: 4.40-160.78, P<0.001; severe PH vs. none HR =36.49, 95% CI: 5.65-235.84, P<0.001). Male, preeclampsia and inhaled nitric oxide were also associated with mortality. Mild PH was significantly associated with readmission (OR =2.42, 95% CI: 1.12-5.26, P=0.025), but not associated with mortality (HR =2.09, 95% CI: 0.43-10.18, P=0.36). The PH severity model based on echocardiography accurately informed mortality (AUC 0.79).

CONCLUSIONS

Echocardiogram-assessed PH severity is associated with prognostic outcomes, including mortality and readmission in very preterm infants with BPD. The severity of PH based on echocardiography is a potential predictor of mortality in the first year of life.

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.

Utility of echocardiography in predicting mortality in infants with severe bronchopulmonary dysplasia

OBJECTIVE

To determine the relationship between interventricular septal position (SP) and right ventricular systolic pressure (RVSP) and mortality in infants with severe BPD (sBPD).

STUDY DESIGN

Infants with sBPD in the Children's Hospitals Neonatal Database who had echocardiograms 34-44 weeks' postmenstrual age (PMA) were included. SP and RVSP were categorized normal, abnormal (flattened/bowed SP or RVSP > 40 mmHg) or missing.

RESULTS

Of 1157 infants, 115 infants (10%) died. Abnormal SP or RVSP increased mortality (SP 19% vs. 8% normal/missing, RVSP 20% vs. 9% normal/missing, both p < 0.01) in unadjusted and multivariable models, adjusted for significant covariates (SP OR 1.9, 95% CI 1.2-3.0; RVSP OR 2.2, 95% CI 1.1-4.7). Abnormal parameters had high specificity (SP 82%; RVSP 94%), and negative predictive value (SP 94%, NPV 91%) for mortality.

CONCLUSIONS

Abnormal SP or RVSP is independently associated with mortality in sBPD infants. Negative predictive values distinguish infants most likely to survive.

Cardiac Magnetic Resonance Imaging Evaluation of Neonatal Bronchopulmonary Dysplasia-associated Pulmonary Hypertension

Rationale: Patients with bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH) have increased morbidity and mortality. Noninvasive assessment relies on echocardiograms (echos), which are technically challenging in this population. Improved assessment could augment decisions regarding PH therapies.Objectives: We hypothesized that neonatal cardiac magnetic resonance imaging (MRI) will correlate with BPD severity and predict short-term clinical outcomes, including need for PH therapies for infants with BPD.Methods: A total of 52 infants (31 severe BPD, 9 moderate BPD, and 12 with either mild or no BPD) were imaged between 39 and 47 weeks postmenstrual age on a neonatal-sized, neonatal ICU-sited 1.5-T magnetic resonance (MR) scanner. MR left ventricular eccentricity index (EI), main pulmonary artery-to-aorta (PA/AO) diameter ratio, and pulmonary arterial blood flow were determined. Echos obtained for clinical indications were reviewed. MRI and echo indices were compared with BPD severity and clinical outcomes, including length of stay (LOS), duration of respiratory support, respiratory support at discharge, and PH therapy.Measurements and Main Results: PA/AO ratio increased with BPD severity. Increased PA/AO ratio, MR-EI, and echo-EIs were associated with increased LOS and duration of respiratory support. No correlation was seen between pulmonary arterial blood flow and BPD outcomes. Controlling for gestational age, birth weight, and BPD severity, MR-EI was associated with LOS and duration of respiratory support. Increased PA/AO ratio and MR-EI were associated with PH therapy during hospitalization and at discharge.Conclusions: MRI can provide important image-based measures of cardiac morphology that relate to disease severity and clinical outcomes in neonates with BPD.

Diminished right ventricular function at diagnosis of pulmonary hypertension is associated with mortality in bronchopulmonary dysplasia

Pulmonary vascular disease and resultant pulmonary hypertension (PH) have been increasingly recognized in the preterm population, particularly among patients with bronchopulmonary dysplasia (BPD). Limited data exist on the impact of PH severity and right ventricular (RV) dysfunction at PH diagnosis on outcome. The purpose of this study was to evaluate if echocardiography measures of cardiac dysfunction and PH severity in BPD-PH were associated with mortality. The study is a retrospective analysis of the echocardiography at three months or less from time of PH diagnosis. Survival analysis using a univariate Cox proportional hazard model is presented and expressed using hazard ratios (HR). We included 52 patients with BPD and PH of which 16 (31%) died at follow-up. Average gestational age at birth was 26.3 ± 2.3 weeks. Echocardiography was performed at a median of 43.3 weeks (IQR: 39.0–54.7). The median time between PH diagnosis and death was 117 days (range: 49–262 days). Multiple measures of PH severity and RV performance were associated with mortality (sPAP/sBP: HR 1.02, eccentricity index: HR 2.02, tricuspid annular plane systolic excursion Z-score: HR 0.65, fractional area change: HR 0.88, peak longitudinal strain: HR 1.22). Hence, PH severity and underlying RV dysfunction at PH diagnosis were associated with mortality in BPD-PH patients. While absolute estimation of pulmonary pressures is not feasible in every screening echocardiography, thorough evaluation of RV function and other markers of PH may allow to discriminate the most at-risk population and should be considered as standard add-ons to the current screening at 36 weeks.

Hemodynamic management in chronically ventilated infants

Positive pressure ventilation can significantly alter hemodynamics. The reduction in systemic venous return and increase in right ventricular afterload in response to an inappropriately high mean airway pressure can decrease pulmonary blood flow and compromise systemic perfusion as a result. In addition to ventilator parameters, the degree of hemodynamic effects depends on the baseline cardiac function and lung compliance. Furthermore, the chronically ventilated infants often have a multitude of comorbidities which may also impact hemodynamics. These include pulmonary and systemic hypertension which can lead to myocardial dysfunction as a result of the increase in the right and left ventricular afterload, respectively. In this section, we aim to outline the hemodynamic changes associated with chronic lung disease and mechanical ventilation and discuss management options.

Right ventricular myocardial performance index in pediatric patients with bronchopulmonary dysplasia-related pulmonary hypertension

INTRODUCTION

This study aims to assess the utility of right ventricular myocardial performance index (RVMPI) as a potential echocardiographic tool to evaluate and serially follow patients with bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH).

METHODS

We performed a retrospective chart review of all hemodynamic cardiac catheterizations performed January 2011 to December 2016 in patients born premature and with diagnosed BPD up to 4 years of age-excluding patients with significant congenital heart defects. Echocardiograms performed within 24 hours of the cardiac catheterization were reviewed, and a blinded RVMPI was calculated. The primary endpoint was correlation of invasive catheterization hemodynamics to noninvasive echocardiographic RVMPI measurement.

RESULTS

A total of 49 individual patients met complete study criteria, and 10 of those patients underwent repeat cardiac catheterization. Median age at the time of assessment was 8 months (25%-75%, 4-18 months), and the cohort had a calculated RVMPI mean of 0.39 (±0.19), with 73% (43/59) having a RVMPI >0.28. A statistically significant correlation was found between the RVMPI and the baseline hemodynamics during catheterization with regard to the initial mean pulmonary arterial pressure (r = 0.58; P < 0.01) as well as the calculated pulmonary vascular resistance (r = 0.34; P = 0.01).

CONCLUSIONS

This study demonstrates the utility of RVMPI for evaluation of PH in patients with prematurity and BPD. An increased RVMPI by noninvasive echocardiography was found to correlate with increased mean pulmonary arterial pressure and pulmonary vascular resistance measured during invasive cardiac catheterization. Large-scale validation of this study is being planned.

EXPRESS: Sildenafil for bronchopulmonary dysplasia and pulmonary hypertension: a meta-analysis

Bronchopulmonary dysplasia (BPD) is the most common complication in preterm infants and often complicated by pulmonary hypertension (PH), leading to substantial morbidity and mortality. Sildenafil is often used to treat PH and improve symptoms in this condition, even though evidence of safety and effectiveness is scarce. The aim of this study was to perform a systematic review and meta-analysis about the effectiveness and safety of chronic use of sildenafil in preterm infants with BPD-associated PH. Data sources were PubMed, EMBASE, and Medline. Studies reporting the effectiveness of sildenafil therapy in BPD-associated PH in newborns and infants were included. All-cause mortality, improvement in PH, improvement in respiratory scores, and adverse events were extracted. Five studies were included, yielding a total of 101 patients with 94.2 patient-years of total follow-up. The pooled mortality rate was 29.7%/year (95% confidence interval [CI] = 6.8–52.7). Estimated pulmonary arterial pressure improved > 20% in 69.3% (95% CI = 56.8–81.8) of patients within 1–6 months. Respiratory scores improved in 15.0% (95% CI = 0.0–30.4) of patients within 2–7 days. There were no serious adverse events during sildenafil therapy. This systematic review shows that in the treatment of BPD-associated PH in preterm infants, sildenafil may be associated with improvement in PAP and respiratory scores. However, there is no clear evidence of its effect on mortality rates. Considering BPD as a complex disease with variable expression patterns, these results support the need for a prospective registry and standardized approach.

Prospective study of pulmonary hypertension in preterm infants with bronchopulmonary dysplasia

OBJECTIVE

To evaluate the prevalence, risk factors, and optimal timing of echocardiogram for pulmonary hypertension (PH) in infants with bronchopulmonary dysplasia (BPD).

DESIGN

In this prospective study, infants with gestational age (GA) <30 weeks admitted to a tertiary NICU between July 2015 and June 2017 who required positive pressure ventilation or oxygen therapy at ≥28 days of life were evaluated with serial echocardiograms at study enrollment (4-6 weeks of age), 32 weeks (only for ≤25 weeks), 36, and 40 weeks post-menstrual age (PMA) for PH.

RESULTS

Of 126 infants (mean birth weight 858 ± 221 g; mean GA 26.1 ± 1.6 wks), 48 (38%) developed PH at any time during their hospital stay. The first study echocardiogram was performed at a median age of 31 weeks PMA. The prevalence of PH was 36/126 (28.5%) at enrollment, at 6/30 (20%) at 32 weeks, 24/111 (21.6%) at 36 weeks, and 10/59 (17%) at 40 weeks. No new cases of PH were identified at 40 weeks. At 36 weeks, none of the infants with mild BPD had PH, whereas 20% of moderate and 32% of severe BPD infants had PH. After controlling for confounding variables severe BPD (OR 3.31, 95%CI 1.12, 9.74), and ventilator associated pneumonia (VAP) (OR 17.9, 95%CI 3.9, 82.11) remained independent risk factors for BPD-associated PH.

CONCLUSION

Echocardiographic screening for PH can be safely restricted to infants with moderate or severe BPD at 36 weeks PMA. We identified VAP as an independent risk factor for PH.

Developmental outcomes of preterm infants with bronchopulmonary dysplasia-associated pulmonary hypertension at 18-24 months of corrected age

Background

Owing to advances in the critical care of premature infants with bronchopulmonary dysplasia (BPD), BPD-associated pulmonary hypertension (PH) is becoming a growing concern. However, only few investigations were available on neurodevelopmental outcomes in preterm infants with PH. Therefore, this study aimed to identify the impact of PH on growth and neurodevelopment at 18–24 months of corrected age (CA).

Methods

We retrospectively analyzed the medical records of 394 infants (aged < 28 weeks of gestation) admitted to the neonatal intensive care unit between 2005 and 2014. Among the surviving infants, 123 returned for follow-up evaluations including the Bayley Scales of Infant and Toddler Development, third Edition (Bayley-III) screening tests and growth assessment at 18–24 months of CA. Among the 81 infants with moderate or severe BPD, 20 met the criteria for PH. Baseline characteristics and outcomes were compared in infants who developed BPD-associated PH (PH group, n = 20) and moderate or severe BPD infants who did not develop PH (non-PH group, n = 61).

Results

Compared to the non-PH group, the PH group showed significantly lower cognitive (85 vs. 95, p = 0.004), language (81 vs. 89, p = 0.040), and motor (88 vs. 94, p = 0.010) scores of the Bayley-III at 18–24 months of CA. Cognitive delay was found in 45.0% (9/20) of PH infants. In addition, z-scores of weight (− 1.4 ± 1.3 vs. -0.6 ± 1.1%, p = 0.011) and HC (− 1.2 ± 1.8 vs. 0.53 ± 1.0%, p = 0.035) were significantly lower in the BPD with PH group. With the subgroup analysis in infants with severe BPD only, the cognitive score was consistently lower and poorer and weight gain after discharge was identified in infants with PH and severe BPD.

Conclusion

PH was a worsening factor of non-optimal growth and poor neurodevelopmental outcome in preterm infants with BPD at 18–24 months of CA. Our findings suggest the importance of close developmental follow-up and recognition of that risk to help optimize the outcome of preterm infants with PH.

Target oxygen saturation and development of pulmonary hypertension and increased pulmonary vascular resistance in preterm infants

OBJECTIVE

Determine whether higher targeted oxygen levels are associated with reduced incidence of pulmonary hypertension (PH) and elevated pulmonary vascular resistance (PVR) in extremely premature infants.

STUDY DESIGN

Retrospective chart review of 252 extremely preterm infants (<29 weeks), who underwent echocardiogram prior to discharge. PH rates were compared during periods (June 2012-May 2015 and June 2015-April 2016) when lower (88-92%) or higher (90-95%) oxygen saturation targets were used. PH was determined on echocardiography. The ratio of pulmonary artery acceleration time to right ventricular ejection time was computed, with values <0.31 indicative of elevated PVR. Survival analysis compared the effects of oxygen saturation group on development/resolution of PH and elevated PVR.

RESULTS

The higher saturation group had significantly lower risk of developing PH (hazard ratio (HR) = 0.50, 95%CI 0.26-0.95; P = 0.03) or elevated PVR (HR = 0.55, 95%CI 0.38-0.81; P = 0.002), compared to the lower oxygen saturation group. Median time to PH development was significantly shorter in the lower saturation group than in the higher saturation group (5 days vs 12 days; P = 0.02), as was time to development of elevated PVR (4 days vs 6 days; P < 0.001). Duration of PH (P = 0.12) and elevated PVR (P = 0.86) did not differ significantly between groups. Cumulative incidence of PH (P = 0.04) and elevated PVR (P = 0.01) at 36 weeks post-menstrual age was significantly lower in the high saturation group compared to the lower saturation group.

CONCLUSION

Higher targeted oxygen saturation was associated with reduced risk of PH or elevated PVR in extremely preterm infants compared to lower oxygen saturation target.

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.

Facilitated tucking during early neonatologist-performed echocardiography in very preterm neonates

AIM

To assess the effect of facilitated tucking (FT), a nonpharmacologic nursing intervention, on echocardiographic parameters and infant comfort collected prospectively during neonatologist-performed echocardiography.

METHODS

Echocardiography was performed twice, in standard conditions and with FT; the order was randomised by computer. Echocardiography provided data on pulmonary artery flow and pressure, right and left ventricular function, and persistent ductus arteriosus. Comfort was assessed by a behavioural scale of pain, variations in heart rate (HR) and SpO₂ , and a newborn infant parasympathetic evaluation index based on the high-frequency variability in HR.

RESULTS

Fifty newborns, with mean gestational age of 28 [26.6-29.0] weeks and mean birthweight of 950 [780-1190] g, were studied at a postnatal age of 13 [9-27] hours. FT was associated with longer acceleration time/right ventricular ejection time in the main pulmonary artery (p = 0.006), reduced averaged HR variations (p = 0.03) and lower pain scores (p < 0.001). The other haemodynamic parameters and the parasympathetic index were not influenced by FT.

CONCLUSION

Echocardiography performed soon after birth in very premature neonates may generate mild discomfort. FT during echocardiography is associated with lower pulmonary artery pressures and improves infant's comfort during this examination.

An update on the diagnosis and management of bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension

The past decade of neonatal care has been highlighted by increased survival rates in smaller and more premature infants. Despite reduction in mortality associated with extreme prematurity, long term pulmonary morbidities remain a concern, with growing recognition of the clinical burden attributable to infants with bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH). Recent publications shed light on the critical contributions of maternal placental pathology and compromised intrauterine growth to fetal pulmonary vascular development. A body of literature has further clarified postnatal risk factors for PH, most notably the severity of BPD but surprisingly the additional presence of non-pulmonary morbidities including necrotizing enterocolitis (NEC). Limitations of current diagnostics persist with growing consideration of novel echocardiographic approaches as well as complementary non-invasive biomarkers to better identify infants at risk. In 2015, a joint report published by the American Heart Association and American Thoracic Society provided the first guidelines for the care of children with PH with limited content to address BPD-associated PH. These guidelines were expanded upon in an expert consensus report produced by the Pediatric Pulmonary Hypertension Network (PPHNet). These recommendations encouraged the use of standardized screening protocols and emphasized the importance of evaluation and treatment of comorbidities when PH is identified. Cardiac catheterization was recommended prior to initiation of therapy for more accurate quantification of pulmonary pressures, clarification of anatomy and guidance in the use of pharmacotherapy. Despite these guidelines, significant practice variation persists and gaps remain with respect to optimal evaluation and management of BPD-associated PH.

Approach to pulmonary vascular disease in the ICU

PURPOSE OF REVIEW

Pulmonary vascular disease (PVD) complicates the course of many cardiovascular, pulmonary and other systemic diseases in children. The physiological sequelae (pulmonary hypertension and elevated pulmonary vascular resistance) can overwhelm the right ventricle and lead to circulatory collapse. Despite the common end-point, the preceding pathophysiology is complex and variable and requires a tailored approach to diagnosis and management. In this article, we will review the most recent evidence and explore an approach to current controversies in the diagnosis and management of common or challenging patient subgroups.

RECENT FINDINGS

New methods of interpreting data derived from echocardiography and cardiac magnetic resonance imaging may assist in risk stratification and response to therapy. In specific patient subgroups, standard pharmacological therapies to reduce right ventricle afterload may be overutilized, ineffective and in some cases harmful. In the patient failing pharmacological therapy, new and novel techniques are being explored including temporary extracorporeal mechanical circulatory support, pumpless lung assist devices and novel surgical and catheterization procedures.

SUMMARY

PVD is a diverse entity, and attention to the underlying pathophysiology is essential for appropriate management. Despite significant advances in our understanding, the majority of data comes from small uncontrolled studies and must be interpreted with caution.

Identification of gaps in the current knowledge on pulmonary hypertension in extremely preterm infants: A systematic review and meta-analysis

BACKGROUND

Pulmonary hypertension complicates the clinical course of extremely preterm infants and is associated with bronchopulmonary dysplasia (BPD). However, prevalence, risk factors, and outcome of pulmonary hypertension in these infants are insufficiently known. This systematic review and meta-analysis aims to provide an up-to-date overview of available data on prevalence, risk factors, and outcome of pulmonary hypertension and to identify current knowledge gaps.

METHODS

Medline, EMBASE, and the Cochrane Library databases were searched in July 2017. Two authors reviewed titles/abstracts and full-texts. Eligible studies reported prevalence, patient characteristics or mortality of infants with/without pulmonary hypertension. Studies were excluded if they did not include extremely preterm infants. Only similar study samples (selected infants with BPD or infants both with/without BPD) were compared in the meta-analyses.

RESULTS

Of 1829 unique articles identified, 25 were eligible for inclusion. Pulmonary hypertension was observed in infants with BPD (20%, 95% confidence interval [CI] 14, 25), but also in those without BPD (2%, 95% CI 0, 8). Infants with severe BPD were most at risk of pulmonary hypertension (risk ratio [RR] 2.7, 95% CI 1.7, 4.2). Infants with pulmonary hypertension were more at risk of mortality (RR 4.7, 95% CI 2.7, 8.3).

CONCLUSIONS

Pulmonary hypertension occurs in particularly in infants with severe BPD, and increases risk of mortality. Due to selected study populations, heterogeneous pulmonary hypertension-definitions and poorly reported timing of pulmonary hypertension assessments, however, data available in current reports are insufficient to allow accurate assessment of true prevalence, risk factors, and time-related outcome. Prospective studies, with standardised methodology and follow-up are needed to determine these factors.

Inter-observer reliability of preoperative cardiopulmonary exercise test interpretation: a cross-sectional study

BACKGROUND

Despite the increasing importance of cardiopulmonary exercise testing (CPET) for preoperative risk assessment, the reliability of CPET interpretation is unclear. We aimed to assess inter-observer reliability of preoperative CPET.

METHODS

We conducted a prospective, multi-centre, observational study of preoperative CPET interpretation. Participants were professionals with previous experience or training in CPET, assessed by a standardized questionnaire. Each participant interpreted 100 tests using standardized software. The CPET variables of interest were oxygen consumption at the anaerobic threshold (AT) and peak oxygen consumption (VO₂ peak). Inter-observer reliability was measured using intra-class correlation coefficient (ICC) with a random effects model. Results are presented as ICC with 95% confidence interval, where ICC of 1 represents perfect agreement and ICC of 0 represents no agreement.

RESULTS

Participants included 8/28 (28.6%) clinical physiologists, 10 (35.7%) junior doctors, and 10 (35.7%) consultant doctors. The median previous experience was 140 (inter-quartile range 55-700) CPETs. After excluding the first 10 tests (acclimatization) for each participant and missing data, the primary analysis of AT and VO₂ peak included 2125 and 2414 tests, respectively. Inter-observer agreement for numerical values of AT [ICC 0.83 (0.75-0.90)] and VO₂ peak [ICC 0.88 (0.84-0.92)] was good. In a post hoc analysis, inter-observer agreement for identification of the presence of a reportable AT was excellent [ICC 0.93 (0.91-0.95)] and a reportable VO₂ peak was moderate [0.73 (0.64-0.80)].

CONCLUSIONS

Inter-observer reliability of interpretation of numerical values of two commonly used CPET variables was good (>80%). However, inter-observer agreement regarding the presence of a reportable value was less consistent.

Diagnostic Approach to Pulmonary Hypertension in Premature Neonates

Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease in premature infants following respiratory distress at birth. With increasing survival of extremely low birth weight infants, alveolar simplification is the defining lung characteristic of infants with BPD, and along with pulmonary hypertension, increasingly contributes to both respiratory morbidity and mortality in these infants. Growth restricted infants, infants born to mothers with oligohydramnios or following prolonged preterm rupture of membranes are at particular risk for early onset pulmonary hypertension. Altered vascular and alveolar growth particularly in canalicular and early saccular stages of lung development following mechanical ventilation and oxygen therapy, results in developmental lung arrest leading to BPD with pulmonary hypertension (PH). Early recognition of PH in infants with risk factors is important for optimal management of these infants. Screening tools for early diagnosis of PH are evolving; however, echocardiography is the mainstay for non-invasive diagnosis of PH in infants. Cardiac computed tomography (CT) and magnetic resonance are being used as imaging modalities, however their role in improving outcomes in these patients is uncertain. Follow-up of infants at risk for PH will help not only in early diagnosis, but also in appropriate management of these infants. Aggressive management of lung disease, avoidance of hypoxemic episodes, and optimal nutrition determine the progression of PH, as epigenetic factors may have significant effects, particularly in growth-restricted infants. Infants with diagnosis of PH are managed with pulmonary vasodilators and those resistant to therapy need to be worked up for the presence of cardio-vascular anomalies. The management of infants and toddlers with PH, especially following premature birth is an emerging field. Nonetheless, combination therapies in a multi-disciplinary setting improves outcomes for these infants.

Early characteristics of infants with pulmonary hypertension in a referral neonatal intensive care unit

Background

Approximately 8–23% of premature infants develop pulmonary hypertension (PH), and this diagnosis confers a higher possibility of mortality. As a result, professional societies recommend PH screening in premature infants. However, the risk factors for and the outcomes of PH may differ depending on the timing of its diagnosis, and little evidence is available to determine at-risk infants in the referral neonatal population. The objective of this study was to define clinical and echocardiographic characteristics of infants with pulmonary hypertension during the neonatal hospital course and at or near-term.

Methods

Infants who had the following billing codes: < 32 weeks, birth weight < 1500 g, neonatal unit, and echocardiograph had records abstracted from a data warehouse at Children’s Healthcare of Atlanta. The outcome was defined as late PH on the final echocardiogram for all patients, and, separately, for patients with multiple studies. Descriptive statistics, univariable, and multivariable models were evaluated, and odds ratios and 95% confidence intervals are expressed below as (OR, CI).

Results

556 infants were included in the overall study, 59 had PH on their final echocardiogram (11%). In multivariable analyses, atrial septal defect (2.9, 1.4–6.1), and intrauterine growth restriction (2.7, 1.2–6.3) increased the odds of late PH, whereas caffeine therapy decreased PH (0.4, 0.2–0.8). When the analyses were restricted to 32 infants who had multiple echocardiograms during their hospitalization, the association between atrial septal defect (5.9, 2.0–16.5) and growth restriction (3.7, 1.3–10.7) and late PH was strengthened, but the effect of caffeine therapy was no longer significant. In this smaller subgroup, infants with late PH had their final echocardiogram at a median of 116 days of life, and 42–74% of them had right ventricular pathology.

Conclusions

Early clinical variables are associated with PH persistence in a referral neonatal population. Identification of early clinical factors may help guide the ascertainment of infant risk for late PH, and may aid in targeting sub-groups that are most likely to benefit from PH screening.