Interventricular septal configuration as a predictor of right ventricular systolic hypertension in children: a cross-sectional echocardiographic study

Navigating Diagnostic and Treatment Challenges of Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia

Advances in perinatal intensive care have significantly enhanced the survival rates of extremely low gestation-al-age neonates but with continued high rates of bronchopulmonary dysplasia (BPD). Nevertheless, as the survival of these infants improves, there is a growing awareness of associated abnormalities in pulmonary vascular development and hemodynamics within the pulmonary circulation. Premature infants, now born as early as 22 weeks, face heightened risks of adverse development in both pulmonary arterial and venous systems. This risk is compounded by parenchymal and airway abnormalities, as well as factors such as inflammation, fibrosis, and adverse growth trajectory. The presence of pulmonary hypertension in bronchopulmonary dysplasia (BPD-PH) has been linked to an increased mortality and substantial morbidities, including a greater susceptibility to later neurodevelopmental challenges. BPD-PH is now recognized to be a spectrum of disease, with a multifactorial pathophysiology. This review discusses the challenges associated with the identification and management of BPD-PH, both of which are important in minimizing further disease progression and improving cardiopulmonary morbidity in the BPD infant.

Correlating Severity of Pulmonary Hypertension by Echocardiogram with Mortality in Premature Infants with Bronchopulmonary Dysplasia

OBJECTIVE

 Bronchopulmonary dysplasia (BPD) is the most common complication of preterm birth. Infants with BPD are at increased risk for pulmonary hypertension (PH). Cardiac catheterization is the gold standard for diagnosing PH, but cardiac catheterization is challenging to perform in small, sick, premature infants. The utility of echocardiography for diagnosing PH and predicting outcomes in extremely premature infants has not been clearly defined. Therefore, we sought to use predefined criteria to diagnose PH by echocardiogram and relate PH severity to mortality in extremely premature infants with BPD.

STUDY DESIGN

 Echocardiograms from 46 infants born ≤28 weeks' postmenstrual age with a diagnosis of BPD were assessed for PH by three pediatric cardiologists using predefined criteria, and survival times among categories of PH patients were compared. A total of 458 echocardiograms were reviewed, and 15 (33%) patients were found to have at least moderate PH. Patients with at least moderate PH had similar demographic characteristics to those with no/mild PH.

RESULTS

 Ninety percent of infants without moderate to severe PH survived to hospital discharge, compared with 67% of infants with at least moderate PH (p = 0.048). Patients with severe PH had decreased survival to hospital discharge (38%) compared with moderate (100%) and no/mild PH (90%) groups. Kaplan-Meier survival curves also differed among PH severity groups (Wilcoxon p < 0.001).

CONCLUSION

 Using predefined criteria for PH, premature infants with BPD can be stratified into PH severity categories. Patients diagnosed with severe PH by echocardiogram have significantly reduced survival.

KEY POINTS

· A composite score definition of PH by echocardiogram showed high inter- and intrarater reliability.. · Infants with severe PH by echocardiogram had decreased survival rates.. · Early diagnosis of PH by echocardiogram dictates treatment which may improve outcomes..

Biventricular finite element modeling of the fetal heart in health and during critical aortic stenosis

Finite Element simulations are a robust way of investigating cardiac biomechanics. To date, it has only been performed with the left ventricle (LV) alone for fetal hearts, even though results are likely different with biventricular (BiV) simulations. In this research, we conduct BiV simulations of the fetal heart based on 4D echocardiography images to show that it can capture the biomechanics of the normal healthy fetal heart, as well as those of fetal aortic stenosis better than the LV alone simulations. We found that performing LV alone simulations resulted in overestimation of LV stresses and pressures, compared to BiV simulations. Interestingly, inserting a compliance between the LV and right ventricle (RV) in the lumped parameter model of the LV only simulation effectively resolved these overestimations, demonstrating that the septum could be considered to play a LV-RV pressure communication role. However, stresses and strains spatial patterns remained altered from BiV simulations after the addition of the compliance. The BiV simulations corroborated previous studies in showing disease effects on the LV, where fetal aortic stenosis (AS) drastically elevated LV pressures and reduced strains and stroke volumes, which were moderated down with the addition of mitral regurgitation (MR). However, BiV simulations enabled an evaluation of the RV as well, where we observed that effects of the AS and MR on pressures and stroke volumes were generally much smaller and less consistent. The BiV simulations also enabled investigations of septal dynamics, which showed a rightward shift with AS, and partial restoration with MR. Interestingly, AS tended to enhance RV stroke volume, but MR moderated that down.

Serial tissue Doppler imaging in the evaluation of bronchopulmonary dysplasia-associated pulmonary hypertension among extremely preterm infants: a prospective observational study

Objectives

To evaluate serial tissue Doppler cardiac imaging (TDI) in the evolution of bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) among extremely preterm infants.

Design

Prospective observational study.

Setting

Single-center, tertiary-level neonatal intensive care unit.

Patients

Infant born <28 weeks gestation.

Main outcome measures

Utility of TDI in the early diagnosis and prediction of BPD-PH and optimal timing for screening of BPD-PH.

Results

A total of 79 infants were included. Of them, 17 (23%) had BPD-PH. The mean gestational age was 25.9 ± 1.1 weeks, and mean birth weight was 830 ± 174 g. The BPD-PH group had a high incidence of hemodynamically significant patent ductus arteriosus (83% vs. 56%, p < 0.018), longer oxygen days (96.16 ± 68.09 vs. 59.35 ± 52.1, p < 0.008), and prolonged hospital stay (133.8 ± 45.9 vs. 106.5 ± 37.9 days, p < 0.005). The left ventricular eccentricity index (0.99 ± 0.1 vs. 1.1 ± 0.7, p < 0.01) and the ratio of acceleration time to right ventricular ejection time showed a statistically significant trend from 33 weeks (0.24 ± 0.05 vs. 0.28 ± 0.05, p < 0.05). At 33 weeks, the BPD-PH group showed prolonged isovolumetric contraction time (27.84 ± 5.5 vs. 22.77 ± 4, p < 0.001), prolonged isovolumetric relaxation time (40.3 ± 7.1 vs. 34.9 ± 5.3, p < 0.003), and abnormal myocardial performance index (0.39 ± 0.05 vs. 0.32 ± 0.03, p < 0.001). These differences persisted at 36 weeks after conceptional gestational age.

Conclusions

TDI parameters are sensitive in the early evolution of BPD-PH. Diagnostic accuracy can be increased by combining the TDI parameters with conventional echocardiographic parameters. BPD-PH can be recognizable as early as 33-34 weeks of gestation.

Postnatal cytomegalovirus infection and pulmonary vascular disease in extremely premature infants: A case series

BACKGROUND

Pulmonary vascular disease (PVD) is a major determinant of both morbidity and mortality in extremely low birth weight infants. It is biologically plausible that postnatal cytomegalovirus (pCMV) infection may lead to PVD in premature infants secondary to pneumonitis or via derangement of pulmonary vascular development directly through endothelial dysfunction. Uncertainty remains, however, regarding thresholds for intervention in premature infants with cardiorespiratory instability and presumed CMV infection likely secondary to the limited understanding of the natural history of the disease.

METHODS/RESULTS

We describe four cases of premature infants with clinical and echocardiography features of PVD, in the setting of postnatally acquired CMV. All patients had atypical PVD trajectories, refractory to vasodilator treatment, which improved after initiation of CMV treatment.

CONCLUSION

We highlight the need to consider postnatally acquired CMV infection in patients with PVD non-responsive to standard pulmonary vasodilator therapies or disease severity which is out of proportion of the usual clinical trajectory. Treatment of extremely premature infants with CMV-associated PVD may have positive impact on cardiorespiratory health, although duration of therapy remains uncertain.

Echocardiographic Patterns of Abnormal Septal Motion: Beyond Myocardial Ischemia

Abnormal septal motion (ASM), which often is associated with myocardial ischemia, is also observed in other diseases. Owing to the position of the interventricular septum (IVS) in the heart, its movement not only relies on contractile properties but is also affected by the pressure gradient between the 2 ventricles and by the mode of electrical activation. Echocardiography allows the operator to focus on the motion of the IVS, analyzing its characteristics and thereby gaining information about the possible underlying pathophysiological mechanism. In this review, we focused on the main echocardiographic patterns of ASM that are not related to a failure of contractile properties of the septum (i.e., acute coronary syndrome and cardiomyopathies), showing their pathophysiological mechanisms and underlining their diagnostic usefulness in clinical practice.

Aortic Steal Correlates with Acute Organ Dysfunction and Short-Term Outcomes in Neonates with Vein of Galen Malformation

INTRODUCTION

Vein of Galen aneurysmal malformation (VGAM) is a rare, congenital cerebrovascular malformation with high morbidity and mortality. Parameters to foresee clinical progression and allow individualized parent counseling are lacking. The aim of this study was to evaluate aortic steal measured by Doppler ultrasound as a prognostic parameter in these neonates.

METHODS

A retrospective monocentric analysis of cardiac ultrasound exams before embolization in neonates with VGAM was conducted. Percentage of aortic steal measured by time-averaged maximum velocity above and below the zero flow baseline by pulsed Doppler ultrasound at the preductal aortic isthmus was calculated. Association of aortic steal with parameters of acute organ dysfunction (Bicêtre neonatal evaluation score [BNES], neonatal multiple organ dysfunction score [NeoMODS]) and mortality and determination of correlation between aortic steal and cerebral damage on initial and follow-up cerebral magnetic resonance imaging (cMRI) were evaluated.

RESULTS

Twelve neonates were included, of which 3 died. Per 10 percentage point increase of aortic steal, BNES decreased by 1.64 (95% confidence interval [CI]: 1.28-2.0) points and the maximum observed NeoMODS increased by 1.25 (CI: 0.94-1.57) points. The odds for mortality increased by 2.3 (CI: 1.14-13.67) per 10 percentage point increase of aortic steal. There was a correlation between aortic steal and cerebral damage at baseline (white matter ρ [rho] = 0.34, gray matter ρ = 0.81) and follow-up (white matter ρ = 0.80, gray matter ρ = 0.72).

CONCLUSION

The degree of aortic steal in neonates with VGAM was highly associated with the severity of organ dysfunction, disease progression on cMRI, and mortality.

Patent ductus arteriosus shunting direction and diameter predict inpatient outcomes in newborns with congenital diaphragmatic hernia

Objective

To evaluate whether the patent ductus arteriosus (PDA) can serve as a predictive factor for inpatient outcomes in congenital diaphragmatic hernia (CDH) patients.

Methods

A retrospective cohort study was conducted on 59 CDH patients at the Capital Institute of Pediatrics from January 2020 to August 2022. Echocardiography was performed at least three times: within 2-3 h after birth, pre-operatively, and post-operatively of CDH surgery. Based on the direction of the PDA shunt in the first echocardiogram, patients were classified into three groups: left-to-right shunting or closed PDA (L-R), bi-directional shunting, and right-to-left shunting (R-L).

Results

The mortality rate was 15.3% (9/59), with all non-survivors having R-L shunting and group mortality of 39.1% (9/23). The direction of the PDA shunt was significantly associated with the duration of ventilation and length of hospital stay (p < 0.05). Decreased PDA diameter or pre-operative shunting direction change towards L-R or bi-directional shunting were associated with higher survival rates, while increased PDA diameter or continuous R-L shunting were associated with higher mortality rates. Pre-operative PDA shunt direction, PDA size after birth and before surgery, gestational age of diagnosis, and shortening fraction before surgery were significantly correlated with patient outcomes. The direction of the preoperative PDA shunt was the most relevant factor among these relationships (p = 0.009, OR 20.6, CI 2.2∼196.1).

Conclusion

Our findings highlight the importance of monitoring changes in PDA shunt directionality and diameter in the early stage after birth, as these parameters may serve as valuable predictors of patient outcomes.

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.

Pulmonary Hypertension in Infants and Children with Vein of Galen Malformation and Association with Clinical Outcomes

OBJECTIVE

To assess the extent and resolution of pulmonary hypertension (PH), cardiovascular factors, and echocardiographic findings associated with mortality in infants and children with vein of Galen malformation (VOGM).

STUDY DESIGN

We performed a retrospective review of 49 consecutive children with VOGM admitted to Boston Children's Hospital from 2007 to 2020. Patient characteristics, echocardiographic data, and hospital course were analyzed for 2 cohorts based on age at presentation to Boston Children's Hospital: group 1 (age ≤60 days) or group 2 (age >60 days).

RESULTS

Overall hospital survival was 35 of 49 (71.4%); 13 of 26 (50%) in group 1 and 22 of 23 (96%) in group 2 (P < .001). High-output PH (P = .01), cardiomegaly (P = .011), intubation (P = .019), and dopamine use (P = .01) were significantly more common in group 1 than group 2. Among patients in group 1, congestive heart failure (P = .015), intubation (P < .001), use of inhaled nitric oxide (P = .015) or prostaglandin E1 (P = .030), suprasystemic PH (P = .003), and right-sided dilation were significantly associated with mortality; in contrast, left ventricular volume and function, structural congenital heart disease, and supraventricular tachycardia were not associated. Inhaled nitric oxide achieved no clinical benefit in 9 of 11 treated patients. Resolution of PH was associated with overall survival (P < .001).

CONCLUSIONS

VOGM remains associated with substantial mortality among infants presenting at ≤60 days of life owing to factors associated with high output PH. Resolution of PH is an indicator associated with survival and a surrogate end point for benchmarking outcomes.

Pulmonary artery acceleration time in young children is determined by heart rate and transpulmonary gradient but not by pulmonary blood flow: A simultaneous echocardiography-cardiac catheterization study

INTRODUCTION

Pulmonary artery acceleration time (PAAT) is considered useful for the non-invasive evaluation of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR). PAAT is dependent on PAP, PVR, pulmonary artery compliance, stroke volume, and heart rate. Its relative dependency on these determinants may differ between young and older children, raising uncertainty regarding its utility in young children. We aim to identify the primary determinants of the PAAT in children less than 36 months undergoing cardiac catheterization and its utility for the diagnosis of elevated PVR.

METHODS

We prospectively studied 42 children undergoing cardiac catheterization and simultaneous echocardiography. We determined the correlations of PAAT to the above-mentioned determinants and evaluated receiver operator characteristic (ROC) curves for diagnosis of PVR indexed to body surface area (PVRi) ≥3 Wu*m² .

RESULTS

Median age was 11.5 (IQR 5.2, 21.2) months. Moderate correlations were found between PAAT and mean PAP (R = -.66, p < .001), PVRi (R = -.54, p = .004), pulmonary artery compliance (R = .65, p < .001), transpulmonary gradient (R = -.67, p < .001), stroke volume (R = .61, p = .002), and heart rate (R = -.63, p < .001). In multivariate regression modeling, only transpulmonary gradient and heart rate were independent determinants of PAAT. PAAT ≤77 msec had acceptable utility for diagnosing PVRi ≥ 3 Wu*m² (AUC .8 [.64, .95], n = 36), low sensitivity (59%), and excellent specificity (94%).

CONCLUSION

Transpulmonary gradient and heart rate, but not pulmonary blood flow, are important determinants of PAAT in children <36 months undergoing cardiac catheterization. PAAT has low sensitivity for diagnosing elevated PVRi, therefore, should not be solely relied upon in screening for elevated PVRi in young children.

End-Systolic Eccentricity Index Obtained by Enhanced Computed Tomography Is a Predictor of Pulmonary Vascular Resistance in Patients with Chronic Thromboembolic Pulmonary Hypertension

The usefulness of the parameters of biventricular function simultaneously measured using enhanced multi-detector computed tomography (MDCT) pulmonary angiography in patients with chronic thromboembolic pulmonary hypertension (CTEPH) has not been clarified. This study aimed to verify the correlation between left and right ventricular (RV) parameters and pulmonary vascular resistance (PVR). Patients who underwent enhanced MDCT before diagnostic right heart catheterization at Nagoya University Hospital between October 2014 and April 2021 were enrolled. The correlation of biventricular function and volume parameters with PVR was assessed. Eighty patients were retrospectively analyzed. Patients’ mean age was 65 ± 13 years, mean PVR was 9.1 (range, 6.1−11.3) Wood units, and mean end-systolic eccentricity index (esEI) was 1.76 ± 0.50. RV end-systolic volume (ESV) (p = 0.007), RV cardiac output (CO) (p < 0.001), RV ejection fraction (p < 0.001), LV end-diastolic volume (EDV) (p < 0.001), left ventricular (LV) ESV (p = 0.006), LVCO (p < 0.001), end-diastolic EI (p < 0.001), and esEI (p < 0.001) were significantly correlated with PVR. The LVEDV (p = 0.001) and esEI (p < 0.009) were independent predictors of PVR. Systolic pulmonary arterial pressure (PAP) (p < 0.001), diastolic PAP (p < 0.001), mean PAP (p < 0.001), right atrial pressure (p < 0.023), and PVR (p < 0.001) were significantly higher in the high esEI group than in the low esEI group. The esEI was a simple predictor of CTEPH severity.

Pulmonary hypertension associated with vein of Galen malformation. Fetal cardiac hemodynamic findings and physiological considerations

The management of newborns with vein of Galen aneurysmal malformation (VGAM) is clinically challenging for neonatologists and cardiologists. Hemodynamic profiles in four fetuses diagnosed with VGAM who subsequently developed neonatal cardiac failure and pulmonary hypertension were studied using two-dimensional and Doppler echocardiography. All four had an increased cardiothoracic ratio due to right ventricular dilatation on antenatal ultrasound. Doppler studies of the aortic isthmus were abnormal with retrograde flow starting in mid systole and throughout diastole. Left and right ventricular outputs were significantly increased. Net pulmonary flow was highly abnormal with a flow rate almost four times higher than normal. After a short period of clinical stability, all neonates developed cardiac failure and pulmonary hypertension. This article reviews VGAM pathophysiology and the potential relationship between pulmonary hypertension and VGAM, supporting early post-natal treatment of pulmonary hypertension and right ventricular failure.

Role of functional echocardiographic parameters in the diagnosis of bronchopulmonary dysplasia-associated pulmonary hypertension

Echocardiogram (echo) is a commonly used noninvasive modality for the diagnosis of bronchopulmonary dysplasia associated pulmonary hypertension (BPD-PH). Though not considered the gold standard for the diagnosis of BPD-PH, it is an extremely valuable tool in the neonatal and pediatric population, especially when cardiac catheterization is not feasible. In addition to the traditional echo parameters that are used to assess the presence of BPD-PH, much attention has been recently placed on newer bedside echo measures, the so-called functional echo parameters, to aid and assist in the diagnosis. This review article provides a brief introduction to BPD-PH, describes the pitfalls of traditional echo parameters and details the newer echo modalities currently available for the diagnosis of neonatal PH.

Interventricular septal curvature as an additional echocardiographic parameter for evaluating chronic thromboembolic pulmonary hypertension: a single-center retrospective study

BACKGROUND

Noninvasive estimation of the actual systolic pulmonary artery pressure measured via right-sided heart catheterization (sPAP_RHC) is vital for the management of pulmonary hypertension, including chronic thromboembolic pulmonary hypertension (CTEPH). Evaluation related to the interventricular septum (IVS) is generally performed with only visual assessment and has been rarely assessed quantitatively in the field of echocardiography. Thus, this study aimed to investigate the utility of echocardiographic IVS curvature to estimate sPAP_RHC in patients with CTEPH.

METHODS

Medical records of 72 patients with CTEPH were studied retrospectively. We estimated sPAP_RHC using echocardiographic IVS curvature (esPAP_curv) and left ventricular eccentricity index (esPAP_LVEI), and compared their ability to predict sPAP_RHC with estimated sPAP_RHC using tricuspid regurgitant pressure gradient (esPAP_TRPG).

RESULTS

IVS curvature and LVEI were significantly correlated with sPAP_RHC (r = - 0.52 and r = 0.49, respectively). Moreover, the IVS curvature was effective in estimating the sPAP_RHC of patients with trivial tricuspid regurgitation (r = - 0.56) and in determining patients with sPAP_RHC ≥ 70 mmHg with higher sensitivity (77.0%) compared to those with esPAP_TRPG and esPAP_LVEI.

CONCLUSION

Our results indicate that the echocardiographic IVS curvature could be a useful additional tool for estimating sPAP_RHC in CTEPH patients for whom accurate estimation of sPAP_RHC using tricuspid regurgitant pressure gradient is challenging.

Echocardiography-derived septal curvature correlated with invasive hemodynamics in pediatric pulmonary hypertension

BACKGROUND

Right ventricular function and afterload are associated with clinical outcomes in pulmonary hypertension (PH). MRI-derived interventricular septal curvature has been associated with invasive hemodynamics in PH patients. This study sought to determine the relationship of echocardiography derived septal curvature with invasive hemodynamics in pediatric PH patients.

METHODS

A single center chart review identified 56 pediatric patients with PH and 50 control patients with adequate echocardiography to assess septal curvature within one month of initial cardiac catheterization. Echocardiographic indices of septal flattening including end-systolic eccentricity index (EI_s), maximum EI (EI_max), minimum septal curvature (SC_min), and average SC (SC_avg) were determined.

RESULTS

PH patients had a median right ventricular systolic pressure of 64 mmHg (interquartile range (IQR) 48-81), mean pulmonary artery pressure of 44 mmHg (IQR 32-57), pulmonary vascular resistance of 7.9 iWU (IQR 4.8-12.9), and pulmonary capillary wedge pressure of 10 mmHg (IQR 8-12). Patients with PH had higher EIs and EI_max and lower SC_min and SC_avg compared to control patients. SC_avg demonstrated the strongest association with right ventricular systolic pressure (R² 0.73, p < 0.0001), mean pulmonary artery pressure (R² 0.63, p < 0.0001), and pulmonary vascular resistance (R² 0.47, p < 0.0001). All septal curvature indices were associated with the composite adverse outcome, including Potts shunt, lung transplantation, and death. SC_min (HR 0.29; 95%CI 0.07-0.97) and SC_avg (HR 0.15; 95%CI 0.03-0.72) were the only septal flattening indices associated with death.

CONCLUSIONS

Echocardiography derived septal curvature is a non-invasive marker of ventricular afterload and adverse outcomes.

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.

Pulmonary hypertension in a neonatologist-performed echocardiographic follow-up of bronchopulmonary dysplasia

Neonatologist-performed echocardiography (NPE) is an established tool for bedside hemodynamic evaluation, including pulmonary hypertension (PH). PH may complicate bronchopulmonary dysplasia (BPD) course. Aims of this retrospective study were to assess the feasibility of NPE follow-up of infants with BPD and to describe the course of PH of infants with moderate/severe BPD. Preterm infants <32 gestational weeks or birthweight ≤1500 g with moderate/severe BPD underwent NPE follow-up, from 36 weeks postmenstrual age up to 8 months postnatal age. Twenty-three preemies were included (birth weight 840 (213) g, gestational age 26.8 (2.3) weeks); 12/23 developed mild PH, 2/12 after discharge. PH resolved at 8.9 (3.9) months. Clinical and echocardiographic variables did not differ between infants with and without PH, except pulmonary artery acceleration time (PAAT) and PAAT/right ventricle ejection time (RVET) ratio (PAAT: 36 weeks, 68.9 (11.9) vs 52.0 (19.1), p = 0.0443; 6 months: 83.9 (38.9) vs 74.8 (16.9), p = 0.0372). No deaths or admissions for PH were reported. Neonatologist's Image Quality Assessment score attributed by the cardiologist assumed as gold standard was adequate or optimal (9.5/14 total score); inter-rater agreement was excellent (ICC 0.974).Conclusions: NPE follow-up seems to be feasible and safe in both intensive care and outpatient clinic. Mild PH is frequently detected in moderate/severe BPD, with good prognosis. What is Known: • Preterm infants with bronchopulmonary dysplasia (BPD) may develop pulmonary hypertension (PH) and have a late diagnosis. • Neonatologist-performed echocardiography (NPE) is an established tool for bedside hemodynamic evaluation of the neonate. What is New: • To our knowledge this is the first study of NPE follow-up of moderate/severe BPD, describing the course of mild PH from diagnosis to its resolution. • NPE follow-up of BPD seems to be safe and practicable, in both intensive care and outpatient clinic, as long as neonatologists maintain a sound collaboration with pediatric cardiologists.

Echocardiography Monitoring of Pulmonary Hypertension after Pediatric Hematopoietic Stem Cell Transplantation: Pediatric Pulmonary Arterial Hypertension and Pulmonary Veno-Occlusive Disease after Hematopoietic Stem Cell Transplantation

Pulmonary hypertension (PH) is associated with high morbidity in children undergoing hematopoietic stem cell transplantation (HSCT). However, owing to the lack of sequential echocardiography, the nature of the condition is not fully understood. This study was conducted to investigate whether routine echocardiography performed after HSCT could detect patients with PH at an earlier stage and elucidate the role of intervention using tadalafil. The study population comprised 93 consecutive children age <18 years who underwent a total of 109 HSCTs. All patients underwent routine transthoracic echocardiography during HSCT. Four children (4%) with a median age of 4 years (range, 0.7 to 6 years) were found to have PH, and their median tricuspid regurgitation peak velocity (TRV) was 4.1 m/s (range, 3.5 to 4.2 m/s). PH was diagnosed at a median of 52 days (range, 21 to 118 days) after HSCT. Three of them were diagnosed with neuroblastoma, and 1 was diagnosed with infantile leukemia. One patient developed PH after autologous HSCT, and 3 received killer immunoglobulin-like receptor ligand-mismatched cord blood. Busulfan was used for conditioning in all patients, and the proportion of patients receiving this medication was significantly higher in the PH group compared with the non-PH group (100% versus 30%; P = .011). Three of the 4 patients had a durable response (TRV ≤2.8 m/s) at a median of 46 days (range, 14 to 79 days) after starting treatment with tadalafil. No patient experienced exacerbation of PH, and treatment was completed at median of 96 days (range, 46 to 212 days). Our data suggest that routine echocardiography monitoring after HSCT should be considered in children receiving busulfan, although the precise follow-up timing needs further study. In addition, safe and effective administration of tadalafil must be ensured by close monitoring.

Evaluating the Right Ventricle in Acute and Chronic Pulmonary Embolism: Current and Future Considerations

The right ventricle (RV), due to its morphologic and physiologic differences, is susceptible to sudden increase in RV afterload, as noted in patients with acute pulmonary embolism (PE). Functional impairment of RV function is a stronger presage of adverse outcomes in acute PE than the location or burden of emboli. While current iterations of most clinical prognostic scores do not incorporate RV dysfunction, advancements in imaging have enabled more granular and accurate assessment of RV dysfunction in acute PE. RV enlargement and dysfunction on imaging is noted only in a subset of patients with acute PE and is dependent on underlying cardiopulmonary reserve and clot burden. Specific signs like McConnell's and "60/60" sign are noted in less than 20% of patients with acute PE. About 2% of patients with acute PE develop chronic thromboembolic pulmonary hypertension, characterized by continued deterioration in RV function in a subset of patients with a continuum of RV function from preserved to overt right heart failure. Advances in molecular and other imaging will help better characterize RV dysfunction in this population and evaluate the response to therapies.

Cardiovascular magnetic resonance imaging derived septal curvature in neonates with bronchopulmonary dysplasia associated pulmonary hypertension

BACKGROUND

Bronchopulmonary dysplasia (BPD) associated with pulmonary hypertension (PH) is a significant source of morbidity and mortality in premature infants. Recent advances have allowed the use of cardiovascular magnetic resonance (CMR) in the assessment of respiratory and cardiac disease in infants with BPD. In adults and older pediatric patients, decreased CMR interventricular septal curvature correlates with increased mean pulmonary artery pressure and pulmonary vascular resistance. The current study sought to determine the relationship of CMR derived septal curvature in neonates with BPD and BPD-PH with a need for PH therapy.

METHODS

Forty moderate or severe BPD and 12 mild BPD or control infants were imaged without contrast between 38 and 47 weeks post-menstrual age on a neonatal-sized, neonatal intensive care unit-sited 1.5 T CMR scanner. CMR indices including eccentricity index (CMR-EI) and septal curvature were measured and compared to BPD severity and clinical outcomes including hospital length of stay (LOS), duration of respiratory support, respiratory support level at discharge and PH therapy.

RESULTS

CMR-EI was directly associated and septal curvature was inversely associated with BPD severity. In a univariate analysis, CMR-EI and septal curvature were associated with increased hospital LOS, duration of respiratory support, respiratory support at hospital discharge, and need for PH therapy. In multivariable analysis CMR-EI was associated with hospital LOS and duration of respiratory support and septal curvature was associated with respiratory support at hospital discharge. Septal curvature was the only clinical or CMR variable associated with need for PH therapy (R2 = 0.66, p = 0.0014) in multivariable analysis demonstrating improved discrimination beyond CMR-EI.

CONCLUSIONS

CMR derived septal curvature correlates significantly with clinical outcomes including hospital LOS, duration of respiratory support, respiratory support level at hospital discharge, and PH therapy in neonates with BPD and BPD-PH. Further, CMR derived septal curvature demonstrated improved discrimination of need for PH therapy and respiratory support at discharge compared to clinical variables and other CMR indices, supporting septal curvature as a non-invasive marker of PH in this population with potential to guide management strategies.

Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction

Background

Exercise‐induced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise.

Methods and Results

Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at end‐diastole and end‐systole, were measured at rest and peak‐exercise, and compared between the groups. The septum was circular at rest in all 3 groups at end‐diastole. At peak‐exercise, end‐systolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. End‐diastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with end‐systolic NRC (ρ=0.51, P=0.007). In hypertensive controls and healthy controls, peak‐exercise end‐systolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, non‐significant increases in end‐diastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peak‐exercise end‐diastolic NRC also negatively correlated (r=−0.40, P<0.05) with the change in left ventricular end‐diastolic volume with exercise (ie, the Frank‐Starling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=−0.36, P=0.08).

Conclusions

Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the pre‐existing impaired Frank‐Starling response in these patients.

Relationship Between Left Ventricular Geometry and Invasive Hemodynamics in Pediatric Pulmonary Hypertension

Background Ventricular septal flattening, frequently present in pulmonary hypertension (PH), can be quantified using eccentricity index (EI). EI has not been evaluated by concurrent echocardiography and cardiac catheterization and traditionally does not account for postsystolic septal flattening, often seen in PH. We evaluated left ventricular shape, including a novel measure of maximal EI to account for postsystolic septal flattening, to establish the relationship with concurrent invasive hemodynamics. Methods Echocardiography was performed at 2 institutions in 78 pediatric PH patients during cardiac catheterization and in 78 matched controls. From midpapillary parasternal short-axis views, EI and right-to-left ventricular diameter ratio were assessed. Results EI and right-to-left ventricular measures were significantly increased in PH compared with controls. Shape measures correlated with invasive hemodynamics and PH outcome measures (PH-related hospitalization, functional class, medical therapy escalation, and BNP [brain natriuretic peptide]). End-systolic EI of 1.16 best identified the presence of PH, whereas a maximal EI of 1.42 and 1.94 best identified half-systemic and systemic PH, respectively. A maximal EI of 1.27 was associated with an odds ratio of 16.16 (95% CI, 6.62-39.46) for PH-related hospitalization or escalation of therapy. Conclusions Using simultaneous echocardiography and catheterization in the largest study population to date, we demonstrate that EI and right-to-left ventricular ratio correlate with invasive hemodynamics and outcomes measures, and EI can accurately define those with clinically important PH. These measures strengthen the ability of echocardiography to identify and follow pediatric PH patients, especially in the absence of methods to quantify right ventricular systolic pressures.

Right ventricular pressure overload directly affects left ventricular torsion mechanics in patients with precapillary pulmonary hypertension

This study examined the impact of septal flattening on left ventricular (LV) torsion in patients with precapillary pulmonary hypertension (PH). Fifty-two patients with proven precapillary PH and 13 healthy controls were included. Ventricular function was assessed including 4D-measurements, tissue velocity imaging, and speckle tracking analysis. Increased eccentricity index (1.39 vs. 1.08, p<0.001), systolic pulmonary artery pressure (64 vs. 29mmHg, p<0.001) and right ventricular Tei index (0.55 vs. 0.28, p = 0.007), and reduced tricuspid annular plane systolic excursion (19.0 vs. 26.5mm, p<0.001) were detected in PH patients as compared to controls. With increasing eccentricity of left ventricle, LV torsion was both decreased and delayed. Torsion rate paralleled this pattern of change during systole, but not during diastole. In conclusion, right ventricular pressure overload directly affects LV torsion mechanics. The echocardiographic methodology applied provides novel insights in the interrelation of right- and left ventricular function.

Effects of pulmonary endarterectomy on pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension, evaluated by interventricular septum curvature

The interventricular septum curvature, measured in images of electrocardiogram-gated 320-slice multidetector computed tomography, is reportedly useful and less invasive than right heart catheterization, as it could provide clues regarding pulmonary arterial pressure in patients with chronic thromboembolic pulmonary hypertension. Although pulmonary endarterectomy is an efficient treatment for chronic thromboembolic pulmonary hypertension, the interventricular septum curvature in patients who have received pulmonary endarterectomy has not been evaluated. We evaluated whether the interventricular septum curvature on electrocardiogram-gated 320-slice multidetector computed tomography can predict pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension even after pulmonary endarterectomy. We studied 40 patients with chronic thromboembolic pulmonary hypertension (60.5 ± 9.7 years; 30 females), who underwent pulmonary endarterectomy at Chiba University Hospital between December 2010 and July 2018. To measure the interventricular septum curvature, we prepared left ventricular short-axis tomographic images from 4D images of electrocardiogram-gated 320-slice multidetector computed tomography. We calculated the radius of interventricular septum and determined the interventricular septum curvature in both the systolic and diastolic phases. We compared the interventricular septum curvature with pulmonary hemodynamics measured by right heart catheterization before and after pulmonary endarterectomy. After pulmonary endarterectomy, the correlations of the interventricular septum curvature with mean pulmonary arterial pressure, systolic pulmonary arterial pressure, and pulmonary vascular resistance disappeared, although the interventricular septum curvature was correlated with these pulmonary hemodynamic parameters before pulmonary endarterectomy. Changes in systolic interventricular septum curvature revealed significant correlations with changes in mean pulmonary arterial pressure, systolic pulmonary arterial pressure and pulmonary vascular resistance. Diastolic interventricular septum curvature also showed significant correlations with preoperative pulmonary hemodynamics, but not with postoperative pulmonary hemodynamics. Changes in the interventricular septum curvature after pulmonary endarterectomy could estimate the efficacy of pulmonary endarterectomy, although the interventricular septum curvature after pulmonary endarterectomy showed no significant correlations with pulmonary hemodynamics. Additionally, our findings confirmed that the interventricular septum curvature before pulmonary endarterectomy could be used to evaluate the severity of disease.

Identifying Risk Factors for Massive Right Ventricular Dilation in Patients With Repaired Tetralogy of Fallot

In repaired tetralogy of Fallot (rTOF), pulmonary insufficiency results in varying degrees of right ventricle (RV) dilation. A subset of patients is diagnosed at initial cardiac magnetic resonance imaging (CMR) with a massively dilated RV, far beyond pulmonary valve replacement (PVR) criteria, which is unlikely to return to normal size after PVR. This study aimed to identify risk factors for massive RV dilation at initial CMR. This nested case-control study included all patients at our institution with rTOF and massive RV dilation (indexed RV end-diastolic volume [RVEDVi] ≥200 ml/m²) on initial CMR. Patients were matched by age at first CMR, gender, and type of repair with rTOF controls with RVEDVi<200 ml/m². In 39 cases (median RVEDVi 227 ml/m², interquartile range [IQR] 213 to 250) and 73 controls (median RVEDVi 155 ml/m², IQR 130 to 169), repair at >6 months of age, longer QRS duration, and non-Caucasian race were significantly associated with massive RV dilation on univariate analysis. In multivariate analysis, repair at >6 months of age (adjusted odds ratio [AOR] 2.90, 95% confidence interval [CI] 1.12 to 7.55, p = 0.03), longer QRS duration (AOR = 1.03, 95% CI 1.01 to 1.05, p = 0.005), and non-Caucasian race (AOR = 7.84, 95% CI 1.76 to 34.8, p = 0.01) remained independently associated with massive RV dilation. Era of repair, history of systemic to pulmonary shunt palliation, genetic anomaly, and additional cardiac lesions did not differ between groups. In conclusion, these risk factors identify a subset of patients who may benefit from earlier CMR evaluation to avoid massive irreversible RV dilation.

Clinical Utility of Echocardiography in Former Preterm Infants with Bronchopulmonary Dysplasia

BACKGROUND

The clinical utility of echocardiography for the diagnosis of pulmonary vascular disease (PVD) in former preterm infants with bronchopulmonary dysplasia (BPD) is not established. Elevated pulmonary vascular resistance (PVR) rather than pulmonary artery pressure (PAP) is the hallmark of PVD. We evaluated the utility of echocardiography in infants with BPD in diagnosing pulmonary hypertension and PVD (PVR >3 Wood units × m²) assessed by cardiac catheterization.

METHODS

A retrospective single center study of 29 infants born ≤29 weeks of gestational age with BPD who underwent cardiac catheterization and echocardiography was performed. PVD was considered present by echocardiography if the tricuspid valve regurgitation jet peak velocity was >2.9 m/sec, post-tricuspid valve shunt systolic flow velocity estimated a right ventricular systolic pressure >35 mm Hg, or systolic septal flattening was present. The utility (accuracy, sensitivity, and positive predictive value [PPV]) of echocardiography in the diagnosis of PVD was tested. Subgroup analysis in patients without post-tricuspid valve shunts was performed. Echocardiographic estimations of right ventricular pressure, dimensions, function, and pulmonary flow measurements were evaluated for correlation with PVR.

RESULTS

The duration between echocardiography and cardiac catheterization was a median of 1 day (interquartile range, 1-4 days). Accuracy, sensitivity, and PPV of echocardiography in diagnosing PVD were 72%, 90.5%, and 76%, respectively. Accuracy, sensitivity, and PPV increased to 93%, 91.7%, and 100%, respectively, when infants with post-tricuspid valve shunts were excluded. Echocardiography had poor accuracy in estimating the degree of PAP elevation by cardiac catheterization. In infants without post-tricuspid valve shunts, there was moderate to good correlation between indexed PVR and right ventricular myocardial performance index (rho = 0.89, P = .005), systolic to diastolic time index (0.84, P < .001), right to left ventricular diameter ratio at end systole (0.66, P = .003), and pulmonary artery acceleration time (0.48, P = .05).

CONCLUSIONS

Echocardiography performs well in screening for PVD in infants with BPD and may be diagnostic in the absence of a post-tricuspid valve shunt. However, cardiac catheterization is needed to assess the degree of PAP elevation and PVR. The diagnostic utility of echocardiographic measurements that correlate with PVR should be evaluated prospectively in this patient population.

Congenital diaphragmatic hernia-associated pulmonary hypertension

Congenital diaphragmatic hernia (CDH) is a neonatal pathology in which intrathoracic herniation of abdominal viscera via diaphragmatic defect results in aberrant pulmonary and cardiovascular development. Despite decades of study and many advances in the diagnosis and treatment of CDH, morbidity and mortality remain high, largely due to pulmonary hypertension (PH), along with pulmonary hypoplasia and cardiac dysfunction. In patients with CDH, hypoplastic pulmonary vasculature and alterations in multiple molecular pathways lead to pathophysiologic pulmonary vasculopathy and, for severe CDH, sustained, elevated pulmonary arterial pressures. This review addresses the multiple anatomic and physiologic changes that underlie CDH-associated PH (CDH-PH), along with the multimodal treatment strategies that exist currently and future therapies currently under investigation.

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.

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.

Focused Cardiac Ultrasound in Pediatric Pulmonary Hypertension

We present 2 cases of pediatric pulmonary hypertension presenting with respiratory distress. Focused cardiac ultrasound revealed findings consistent with right ventricular dilatation and elevated right ventricular pressure. These findings, in conjunction with the clinical presentation, allowed for early identification and rapid evaluation of a pathologic process that can often go unidentified. In this report, we review the relevant aspects of focused cardiac ultrasound in the setting of pulmonary hypertension.

Death or resolution: the "natural history" of pulmonary hypertension in bronchopulmonary dysplasia

OBJECTIVES

The primary objective was to describe the early "natural history" of pulmonary hypertension (PH) in the premature population. The secondary objective was to describe factors associated with poor outcomes in the premature population with PH at 36 weeks post-menstrual age (PMA).

STUDY DESIGN

Retrospective chart review of patients followed at our institution from 2000 to 2017 with echocardiographic (ECHO) evidence of PH at 36 weeks PMA, and born ≤ 32 weeks estimated gestational age (GA). Cox regression was used for survival analysis.

RESULTS

Sixty-one patients with PH (26.5 ± 1.5 weeks at birth) were included. All PH patients had bronchopulmonary dysplasia (BPD), with 89% considered severe; 38% were small for gestational age. Necrotizing enterocolitis requiring surgery was common (25%). Use of post-natal steroids (HR 11.02, p = 0.01) and increased severity of PH (HR 1.05, p < 0.001) were associated with mortality. Pulmonary vein stenosis (PVS) was documented in 26% of the PH cohort, but not associated with increased mortality. ECHO estimation of pulmonary artery pressure (PAP) was available in 84%. PAP was higher in those who died (sPAP/sBP ratio 1.09 ± 27 vs 0.83 ± 20 %, p = 0.0002). At follow-up (mean 250 ± 186 weeks PMA), 72% of the PH cohort was alive. Most survivors (66%) had resolution of their PH on their most recent ECHO; 31% remained on PH therapy.

CONCLUSION

PH resolved in most survivors in this study population. Mortality in those with BPD-PH was associated with male sex, post-natal steroid use, and increased severity of PH, but not with PVS.

Evaluation and Monitoring of Pulmonary Hypertension in Neonates With Congenital Diaphragmatic Hernia

PURPOSE OF REVIEW

This review aims to describe the assessment of pulmonary hypertension and ventricular function in neonates with congenital diaphragmatic hernia and the long-term follow-up of their pulmonary vascular disease.

RECENT FINDINGS

In 2015, the pediatric pulmonary hypertension guidelines from the American Heart Association and American Thoracic Society suggested class I level of evidence B guidelines for routine evaluation of patients with congenital diaphragmatic hernia, including longitudinal care in an interdisciplinary pulmonary hypertension program and following the recommendations offered for all children with pulmonary hypertension. Congenital diaphragmatic hernia causes compression of the lungs during critical stages of fetal development and results in lung hypoplasia. As a result, there is abnormal development of pulmonary vasculature that leads to post-natal pulmonary hypertension and increased afterload to the right ventricle. Left ventricular filling is affected by decreased pre-load and mechanical compression by abdominal content leading to decreased systemic perfusion. Persistent pulmonary hypertension after surgical repair of congenital diaphragmatic hernia is associated with increased mortality. Assessment and monitoring of pulmonary hypertension and ventricular function in this population of neonates is crucial to determine response to medical treatment, the need for extracorporeal membrane oxygenation, and the timing of surgical repair.

Agreement of an echocardiogram-based diagnosis of pulmonary hypertension in infants at risk for bronchopulmonary dysplasia among masked reviewers

OBJECTIVE

To evaluate the agreement of an echocardiogram-based pulmonary hypertension diagnosis in premature infants at risk for bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Echocardiograms from infants born ≤28 weeks post menstrual age were retrospectively reviewed with a standardized reading protocol by three pediatric cardiologists masked to patient's clinical history to determine the presence of pulmonary hypertension.

RESULTS

A total of 483 echocardiograms from 49 unique patients were each reviewed by three pediatric cardiologists. Overall there was an 82.9% agreement on the presence of pulmonary hypertension among the three readers (95% CI: 78.4%, 85.4%) with a modified Fleiss' kappa of 0.759 (95% CI: 0.711, 0.801). Percent agreement between rereads was 92.4%, and modified Fleiss' kappa was 0.847 (95% CI: 0.750, 0.931).

CONCLUSIONS

Using a standardized reading protocol and echocardiogram-based definition of pulmonary hypertension, there is high inter- and intra-rater agreement for the diagnosis of pulmonary hypertension in at-risk premature infants, suggesting echocardiography can be successfully used for clinical and research monitoring of pulmonary hypertension in infants.

Use of prostaglandin E1 to treat pulmonary hypertension in congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Prostaglandin E1 (PGE) has been used to maintain ductus arteriosus patency and unload the suprasystemic right ventricle (RV) in neonates with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension (PH). Here we evaluate the PH response in neonates with CDH and severe PH treated with PGE.

METHODS

We performed a retrospective chart review of CDH infants treated at our center between 2011 and 2016. In a subset, PGE was initiated for echocardiographic evidence of severe PH, metabolic acidosis, or hypoxemia. To assess PH response, we evaluated laboratory data, including B-type natriuretic peptide (BNP) and echocardiograms before and after PGE treatment. Categorical and continuous data were analyzed with Fisher's exact tests and Mann-Whitney t-tests, respectively.

RESULTS

Fifty-seven infants were treated with PGE a mean 17 ± 2 days. BNP levels declined after 1.4 ± 0.2 days of treatment and again after 5.2 ± 0.6 days. After 6 ± 0.8 days of treatment, echocardiographic estimates of severe PH by tricuspid regurgitation jet velocity, ductus arteriosus direction, and ventricular septum position also improved significantly. Treatment was not associated with postductal hypoxemia or systemic hypoperfusion.

CONCLUSIONS

In patients with CDH and severe PH, PGE is well tolerated and associated with improved BNP and echocardiographic indices of PH, suggesting successful unloading of the RV.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

Level III.

MRI assessment of aortic flow in patients with pulmonary arterial hypertension in response to exercise

Background

While primarily a right heart disease, pulmonary arterial hypertension (PAH) can impact left heart function and aortic flow through a shifted interventricular septum from right ventricular pressure overload and reduced left ventricular preload, among other mechanisms. In this study, we used phase contrast (PC) MRI and a modest exercise challenge to examine the effects of PAH on systemic circulation. While exercise challenges are typically performed with ultrasound in the clinic, MRI exercise studies allow for more reproducible image alignment, more accurate flow quantification, and improved tissue contrast.

Methods

Six PAH patients and fifteen healthy controls (8 older age-matched, 7 younger) exercised in the magnet bore with an MRI-compatible exercise device that allowed for scanning immediately following cessation of exercise. PC scans were performed in the ascending aorta during a breath hold immediately after modest exercise to non-invasively measure stroke volume (SV), cardiac output (CO), aortic peak systolic flow (PSF), and aortic wall stiffness via relative area change (RAC).

Results

Images following exercise showed mild blurring, but were high enough quality to allow for segmentation of the aorta. While SV was approximately 30% lower in PAH patients (SV_PAH,rest = 67 ± 16 mL; SV_PAH,stress = 90 ± 42 mL) than age-matched controls (SV_,older,rest = 93 ± 16 mL; SV_older,stress = 133 ± 40 mL) at both rest and following exercise, CO was similar for both groups following exercise (CO_PAH,stress = 10.8 ± 5.7 L/min; CO_older,stress = 11.8 ± 5.0 L/min). This was achieved through a compensatory increase in heart rate in the PAH subjects (74% increase as compared to 29% in age-matched controls). The PAH subjects also demonstrated reduced aortic peak systolic flow relative to the healthy controls (PSF_PAH,_rest = 309 ± 52 mL/s; PSF_older,_rest = 416 ± 114 mL/s; PSF_PAH,_stress = 388 ± 113 mL/s; PSF_older,_stress = 462 ± 176 mL/s). PAH patients and older controls demonstrated stiffer aortic walls when compared to younger controls (RAC_PAH,rest = 0.15 ± 0.05; RAC_older,rest = 0.17 ± 0.05; RAC_young,rest = 0.28 ± 0.08).

Conclusions

PC MRI following a modest exercise challenge was capable of detecting differences in left heart dynamics likely induced from PAH. These results demonstrated that PAH can have a significant influence on systemic flow, even when the patient has no prior left heart disease. Image quantification following exercise could likely be improved in future studies through the implementation of free-breathing or real-time MRI acquisitions.

Trial registration

Retrospectively registered on 02/26/2018 (TRN:NCT03523910).

Left ventricular torsion rate and the relation to right ventricular function in pediatric pulmonary arterial hypertension

The right ventricle and left ventricle are physically coupled through the interventricular septum. Therefore, changes in the geometry and mechanics of one ventricle can directly affect the function of the other. In treatment of pediatric pulmonary arterial hypertension, the left ventricle is often overlooked, with clinical focus primarily on improving right ventricular function. Pediatric pulmonary arterial hypertension represents a disease distinct from adult pulmonary arterial hypertension based on etiology and survival rates. We aimed to assess left ventricular torsion rate in pediatric pulmonary arterial hypertension and its role in right ventricular dysfunction. Cardiac magnetic resonance images with tissue tagging were prospectively acquired for 18 pediatric pulmonary arterial hypertension (WHO class I) patients and 17 control subjects with no known cardiopulmonary disease. The pulmonary arterial hypertension cohort underwent cardiac magnetic resonance within 48 hours of clinically indicated right heart catheterization. Using right heart catheterization data, we computed single beat estimation of right ventricular end-systolic elastance (as a measure of right ventricular contractility) and ventricular vascular coupling ratio (end-systolic elastance/arterial afterload). Left ventricular torsion rate was quantified from harmonic phase analysis of tagged cardiac magnetic resonance images. Ventricular and pulmonary pressures and pulmonary vascular resistance were derived from right heart catheterization data. Right ventricular ejection fraction and interventricular septum curvature were derived from cardiac magnetic resonance. Left ventricular torsion rate was significantly reduced in pulmonary arterial hypertension patients compared to control subjects (1.40 ± 0.61° vs. 3.02 ± 1.47°, P < 0.001). A decrease in left ventricular torsion rate was significantly correlated with a decrease in right ventricular contractility (end-systolic elastance) ( r = 0.61, P = 0.007), and an increase in right ventricular systolic pressure in pulmonary arterial hypertension kids ( r = -0.54, P = 0.021). In both pulmonary arterial hypertension and control subjects, left ventricular torsion rate correlated with right ventricular ejection fraction (controls r = 0.45, P = 0.034) (pulmonary arterial hypertension r = 0.57, P = 0.032). In the pulmonary arterial hypertension group, interventricular septum curvature demonstrated a strong direct relationship with right ventricular systolic pressure ( r = 0.7, P = 0.001) and inversely with left ventricular torsion rate ( r = -0.57, P = 0.013). Left ventricular torsion rate showed a direct relationship with ventricular vascular coupling ratio ( r = 0.54, P = 0.021), and an inverse relationship with mean pulmonary arterial pressure ( r = -0.60, P = 0.008), and pulmonary vascular resistance ( r = -0.47, P = 0.049). We conclude that in pediatric pulmonary arterial hypertension, reduced right ventricular contractility is associated with decreased left ventricular torsion rate.

Natural History of Postnatal Cardiopulmonary Adaptation in Infants Born Extremely Preterm and Risk for Death or Bronchopulmonary Dysplasia

OBJECTIVE

To study the natural history of postnatal cardiopulmonary adaptation in infants born extremely preterm and establish its association with death or bronchopulmonary dysplasia (BPD).

STUDY DESIGN

This was a prospective, observational, cohort study of infants born extremely preterm (<29 weeks). Initial echocardiogram was performed at <48 hours of life, followed by serial echocardiograms every 24-48 hours until 14 days of life. Resolution or no resolution of pulmonary hypertension (PH) at 72-96 hours was considered normal or delayed postnatal cardiopulmonary adaptation, respectively. PH between 96 hours and 14 days was defined as subsequent PH. Elevated pulmonary artery pressure throughout the 14 days of life was considered persistent PH. BPD was assessed at 36 weeks of postmenstrual age.

RESULTS

Sixty infants were enrolled; 2 died before a sequential echocardiogram could be done at 72-96 hours. Normal and delayed cardiopulmonary adaptation were noted in 26 (45%) and 32 (55%) infants, respectively. Five patterns of postnatal cardiopulmonary adaptation were recognized: normal without subsequent PH (n = 20), normal with subsequent PH (n = 6), delayed adaptation without subsequent PH (n = 6), delayed adaptation with subsequent PH (n = 16), and persistent PH (n = 10). Infants with delayed cardiopulmonary adaptation were of lower gestation and birth weight and required prolonged ventilation and supplemental oxygen (P < .05). On multivariate analysis, the incidence of death or BPD was significantly greater among infants with delayed adaptation (P < .001).

CONCLUSION

Infants born extremely preterm have normal or delayed postnatal cardiopulmonary adaptation that can be complicated by subsequent or persistent PH. Delayed cardiopulmonary adaptation is associated independently with death or BPD.

Impact of high-intensity endurance exercise on regional left and right ventricular myocardial mechanics

Aims

Strenuous endurance exercise acutely increases myocardial wall stress and evokes transient functional cardiac perturbations. However, it is unclear whether exercise-induced functional cardiac disturbances are ubiquitous throughout the myocardium or are segment specific. The aim of this study was to examine the influence of high-intensity endurance exercise on global and segmental left (LV) and right (RV) ventricular tissue deformation (strain).

Methods and results

Echocardiography was used to measure strain in 23 active men (age: 28 ± 2 years; VO2 peak: 4.5 ± 0.7 L min-1) at rest and during a standardized low-intensity exercise challenge, before and after a 90-min high-intensity endurance cycling intervention. Following the cycling intervention, LV and RV global strain decreased at rest (LV: -18.4 ± 0.4% vs. -17.7 ± 0.4%, P < 0.05; RV: -27.6 ± 0.7% vs. -26.4 ± 0.6%, P < 0.05) and by a greater extent during the low-intensity exercise challenge (LV: -21.3 ± 0.4% vs. -19.2 ± 0.5%, P < 0.01; RV: -28.4 ± 0.8% vs. -23.5 ± 0.9%, P < 0.01). Reductions in LV strain were unique to regions of RV attachment (e.g. LV septum: -24.4 ± 0.5% vs. -21.4 ± 0.6%, P < 0.01) with lateral (-18.9 ± 0.4% vs. -18.4 ± 0.5%) and posterior segments (-19.5 ± 0.4% vs. -18.8 ± 0.7%) unaffected. Similarly, augmentation of strain from rest to exercise was abolished in the RV free wall (-1.1 ± 1.0% vs. 2.9 ± 1.2%, P < 0.01), reduced in the septum (-4.6 ± 0.4% vs. -2.4 ± 0.5%, P < 0.01), and unchanged in the lateral (-1.2 ± 0.6% vs. -0.9 ± 0.6%) and posterior walls (-1.7 ± 0.6% vs. -1.3 ± 0.7%).

Conclusion

Changes in ventricular strain following high-intensity exercise are more profound in the right ventricle than in the left ventricle. Reductions in LV strain were unique to the septal myocardium and may reflect ventricular interactions secondary to exercise-induced RV dysfunction.

Quantification of Left Ventricular Shape Differentiates Pediatric Pulmonary Hypertension Subjects From Matched Controls

Changes in left ventricle (LV) shape are observed in patients with pulmonary hypertension (PH). Quantification of ventricular shape could serve as a tool to noninvasively monitor pediatric patients with PH. Decomposing the shape of a ventricle into a series of components and magnitudes will facilitate differentiation of healthy and PH subjects. Parasternal short-axis echo images acquired from 53 pediatric subjects with PH and 53 age and sex-matched normal control subjects underwent speckle tracking using Velocity Vector Imaging (Siemens) to produce a series of x,y coordinates tracing the LV endocardium in each frame. Coordinates were converted to polar format after which the Fourier transform was used to derive shape component magnitudes in each frame. Magnitudes of the first 11 components were normalized to heart size (magnitude/LV length as measured on apical view) and analyzed across a single cardiac cycle. Logistic regression was used to test predictive power of the method. Fourier decomposition produced a series of shape components from short-axis echo views of the LV. Mean values for all 11 components analyzed were significantly different between groups (p < 0.05). The accuracy index of the receiver operator curve was 0.85. Quantification of LV shape can differentiate normal pediatric subjects from those with PH. Shape analysis is a promising method to precisely describe shape changes observed in PH. Differences between groups speak to intraventricular coupling that occurs in right ventricular (RV) overload. Further analysis investigating the correlation of shape to clinical parameters is underway.

Impact of Objective Echocardiographic Criteria for Timing of Congenital Diaphragmatic Hernia Repair

OBJECTIVE

To assess the impact of specific echocardiographic criteria for timing of congenital diaphragmatic hernia repair on the incidence of acute postoperative clinical decompensation from pulmonary hypertensive crisis and/or acute respiratory decompensation, with secondary outcomes including survival to discharge, duration of ventilator support, and length of hospitalization.

STUDY DESIGN

The multidisciplinary congenital diaphragmatic hernia management team instituted a protocol in 2012 requiring the specific criterion of echocardiogram-estimated pulmonary artery pressure ≤80% systemic blood pressure before repairing congenital diaphragmatic hernias. A retrospective review of 77 neonatal patients with Bochdalek hernias repaired between 2008 and 2015 were reviewed: group 1 included patients repaired before protocol implementation (n = 25) and group 2 included patients repaired after implementation (n = 52).

RESULTS

The groups had similar baseline characteristics. Postoperative decompensation occurred less often in group 2 compared with group 1 (17% vs 48%, P = .01). Adjusted analysis accounting for repair type, liver herniation, and prematurity yielded similar results (15% vs 37%, P = .04). Group 2 displayed a trend toward improved survival to 30 days postoperatively, though this did not reach statistical significance (94% vs 80%, P = .06). Patient survival to discharge, duration of ventilator support, and length of hospitalization were not different between groups.

CONCLUSIONS

The implementation of a protocol requiring echocardiogram-estimated pulmonary arterial pressure ≤80% of systemic pressure before congenital diaphragmatic hernia repair may reduce the incidence of acute postoperative decompensation, although there was no difference in longer-term secondary outcomes, including survival to discharge.

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.

Bronchopulmonary dysplasia-associated pulmonary hypertension: clues from placental pathology

OBJECTIVES

Bronchopulmonary dysplasia (BPD) and the associated complication of pulmonary hypertension (PH) leads to increased mortality and a longer length of stay among survivors. Placental histopathology may give early clues of subsequent events. The objective was to evaluate the relationship of maternal vascular underperfusion (MVU) changes on placental histopathology with subsequent development of BPD-associated PH in a cohort of extremely premature infants.

STUDY DESIGN

In a cohort of preterm infants '⩽28 weeks' gestational age (GA) and with 'severe' BPD, this retrospective study evaluated specific placental histopathological changes and assessed the relationship with subsequent development of PH. 'Severe' BPD was defined as the need for ⩾30% oxygen and/or positive pressure ventilation at 36 weeks postmenstrual age. Placental and echocardiographic assessments were done by investigators masked to the grouping and clinical outcomes.

RESULTS

Fifty six infants with severe BPD formed the cohort; PH was noted in 22 (39.3%) infants. The GA of the infants with and without PH was comparable (25.8±1.6 vs 25.8±1.3 weeks, P=0.9). On placental histopathological examination, 13 (23%) had features of MVU. On univariate logistic regression, the presence of changes consistent with MVU increased the relative risk of subsequent BPD-associated PH by 2.75 (95% confidence interval 1.56 to 4.85, P=0.004). The significance persisted after adjustment for GA. Stratification by the presence or absence of fetal growth restriction, yielded nonsignificant associations (P=0.17).

CONCLUSION

Based on the results of the present study, specific placental histopathological changes may give early clues to the subsequent development of BPD-associated PH.

Patient-Specific Computational Analysis of Ventricular Mechanics in Pulmonary Arterial Hypertension

Patient-specific biventricular computational models associated with a normal subject and a pulmonary arterial hypertension (PAH) patient were developed to investigate the disease effects on ventricular mechanics. These models were developed using geometry reconstructed from magnetic resonance (MR) images, and constitutive descriptors of passive and active mechanics in cardiac tissues. Model parameter values associated with ventricular mechanical properties and myofiber architecture were obtained by fitting the models with measured pressure-volume loops and circumferential strain calculated from MR images using a hyperelastic warping method. Results show that the peak right ventricle (RV) pressure was substantially higher in the PAH patient (65 mmHg versus 20 mmHg), who also has a significantly reduced ejection fraction (EF) in both ventricles (left ventricle (LV): 39% versus 66% and RV: 18% versus 64%). Peak systolic circumferential strain was comparatively lower in both the left ventricle (LV) and RV free wall (RVFW) of the PAH patient (LV: -6.8% versus -13.2% and RVFW: -2.1% versus -9.4%). Passive stiffness, contractility, and myofiber stress in the PAH patient were all found to be substantially increased in both ventricles, whereas septum wall in the PAH patient possessed a smaller curvature than that in the LV free wall. Simulations using the PAH model revealed an approximately linear relationship between the septum curvature and the transseptal pressure gradient at both early-diastole and end-systole. These findings suggest that PAH can induce LV remodeling, and septum curvature measurements may be useful in quantifying transseptal pressure gradient in PAH patients.

A modified noninvasive screening protocol for pulmonary hypertension in children with sickle cell disease-Who should be sent for invasive evaluation?

BACKGROUND

Invasive studies have shown that prevalence and severity of pulmonary hypertension (PH) in patients with sickle cell disease (SCD) tend to be overestimated if based exclusively on Doppler-derived tricuspid regurgitant velocity (TRV) as surrogate noninvasive marker with a cutoff ≥2.5 m/s.

OBJECTIVES

We aimed to better define a subgroup of pediatric SCD patients who should be sent for invasive evaluation of pulmonary artery pressure (PAP) based on a modified echocardiographic PH screening protocol that implements evidence from Doppler-catheter comparative studies.

STUDY DESIGN

Charts of 121 pediatric patients with stable SCD were reviewed regarding echocardiographically assessed risk for elevated PAP/PH and associated clinical characteristics. TRV cutoff was refined at ≥2.9 m/s to avoid overestimating the risk for PH. TRV was combined with additional echocardiographic parameters to avoid underestimating the PH risk.

RESULTS

Ninety-one patients qualified for analysis. Based on our modified echocardiographic protocol, 5.5% of patients qualified for at least moderate risk for elevated PAP (compatible with PH) as opposed to 20.9% if based exclusively on TRV ≥2.5 m/s. These patients were older, homozygous for hemoglobin S (HbSS), and more anemic. No subject had an echocardiographic risk constellation suggesting more than mild PH.

CONCLUSIONS

Our modified noninvasive screening protocol-if confirmed by invasive studies-may help to better identify a subgroup of pediatric SCD patients in whom evaluation by catheterization appears justified. Unlike estimates based on the conventional protocol, the size of the targeted subgroup compares favorably with catheterization-confirmed PH prevalence rates. Characteristics associated with an increased PH risk were also identified.

Pulmonary hypertension associated with bronchopulmonary dysplasia in preterm infants

Bronchopulmonary dysplasia (BPD) and BPD-associated pulmonary hypertension (BPD-PH) are chronic inflammatory cardiopulmonary diseases with devastating short- and long-term consequences for infants born prematurely. The immature lungs of preterm infants are ill-prepared to achieve sufficient gas exchange, thus usually necessitating immediate commencement of respiratory support and oxygen supplementation. These therapies are life-saving, but they exacerbate the tissue damage that is inevitably inflicted on a preterm lung forced to perform gas exchange. Together, air-breathing and necessary therapeutic interventions disrupt normal lung development by aggravating pulmonary inflammation and vascular remodelling, thus frequently precipitating BPD and PH via an incompletely understood pathogenic cascade. BPD and BPD-PH share common risk factors, such as low gestational age at birth, fetal growth restriction and perinatal maternal inflammation; however, these risk factors are not unique to BPD or BPD-PH. Occurring in 17-24% of BPD patients, BPD-PH substantially worsens the morbidity and mortality attributable to BPD alone, thus darkening their outlook; for example, BPD-PH entails a mortality of up to 50%. The absence of a safe and effective therapy for BPD and BPD-PH renders neonatal cardiopulmonary disease an area of urgent unmet medical need. Besides the need to develop new therapeutic strategies, a major challenge for clinicians is the lack of a reliable method for identifying babies at risk of developing BPD and BPD-PH. In addition to discussing current knowledge on pathophysiology, diagnosis and treatment of BPD-PH, we highlight emerging biomarkers that could enable clinicians to predict disease-risk and also optimise treatment of BPD-PH in our tiniest patients.

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

OBJECTIVES

To determine the assessment and inter-rater reliability of echocardiographic evaluations of pulmonary vascular disease (PVD) in preterm infants at risk for bronchopulmonary dysplasia.

STUDY DESIGN

We prospectively studied echocardiograms from preterm infants (birthweights 500-1250 g) at 7 days of age and 36 weeks postmenstrual age (PMA). Echocardiograms were assessed by both a cardiologist on clinical service and a single research cardiologist. Interpretations were reviewed for inclusion of determinants of PVD and assessed for inter-rater reliability using the Prevalence Adjusted Bias Adjusted Kappa Score (PABAK).

RESULTS

One hundred eighty and 188 matching research and clinical echocardiogram reports were available for the 7-day and 36-week PMA studies. At least one of the specific qualitative measures of PVD was missing from 54% of the clinical reports. PVD was diagnosed at 7 days in 31% and 20% of research and clinical interpretations, respectively (PABAK score of 0.54). At 36 weeks, PH was diagnosed in 15.6% and 17.8% of research and clinical interpretations, respectively (PABAK score of 0.80).

CONCLUSIONS

Although all qualitative variables of PVD are not consistently provided in echocardiogram reports, the inter-rater reliability of cardiologists evaluating measures of PVD revealed strong agreement, especially at 36 weeks PMA. We speculate that establishment of a protocol for echocardiographic evaluation may improve the identification of PVD in preterm infants.