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

The Role of Early Child Nutrition in Pulmonary Hypertension-A Narrative Review

Pulmonary hypertension is a complex condition that has distinct characteristics in pediatric populations. This review explores the important role of early childhood nutrition in the growth, progression, and management of pediatric pulmonary hypertension. Nutritional deficiencies, including those of vitamins C, D, and iron, are closely linked to worse outcomes in children with this disease, emphasizing the importance of early intervention to prevent malnutrition and promote growth. Emerging research revealed that promising nutrients like resveratrol, along with modulation of the gut and respiratory microbiomes, may offer therapeutic advances for managing pulmonary hypertension. However, the current literature is limited by a lack of pediatric-specific studies, with much of the data extrapolated from adult populations and animal models, especially rats. This review highlights the need for targeted research to develop effective nutritional interventions aimed at improving outcomes for pediatric patients.

Association between early pulmonary arterial pressure measurements and bronchopulmonary dysplasia or mortality in very preterm infants: a prospective cohort study

BACKGROUND

Prematurity is a significant risk for bronchopulmonary dysplasia related pulmonary artery pressure.

OBJECTIVE

To determine the association between pulmonary artery pressure in the early days of life and the development of bronchopulmonary dysplasia or mortality.

METHODS

This prospective observational cohort study included infants born at <32 weeks and weighing <1500 g. Pulmonary artery pressure was measured between postnatal days 3 and 7. Pulmonary hypertension was defined as systolic pulmonary artery pressure ≥40 mm Hg or systolic pulmonary artery pressure/systolic blood pressure >0.5 (pulmonary hypertension criterion-1). Infants were categorised into pulmonary hypertension and non-pulmonary hypertension groups. The primary endpoint was bronchopulmonary dysplasia or mortality. Receiver operating characteristic analysis established a new threshold value for predicting bronchopulmonary dysplasia or mortality (pulmonary hypertension criterion-2). Infants were reanalysed according to new criteria.

RESULTS

A total of 329 infants were included in this study. Moderate-to-severe pulmonary hypertension was identified in 24% (n=79) of the infants. The pulmonary hypertension group exhibited a significantly lower gestational age, lower birth weight and a higher incidence of small for gestational age. Systolic pulmonary artery pressure >25 mm Hg or systolic pulmonary artery pressure/systolic blood pressure >0.35 was defined as the pulmonary hypertension criterion-2. Logistic regression analysis identified pulmonary hypertension criterion-2 as an independent risk factor for moderate-to-severe bronchopulmonary dysplasia or mortality (OR 2.67, 95% CI 1.3 to 5.51, p<0.01).

CONCLUSION

Pulmonary artery pressure exceeding 25 mm Hg in the early days of life may be considered a potential risk factor for bronchopulmonary dysplasia or mortality.

Extracorporeal membrane oxygenation (ECMO) support for children with pulmonary hypertension: A single-institutional experience of outcomes

Pediatric pulmonary arterial hypertension (PAH) can present with a wide spectrum of disease severity. Pulmonary hypertension (PH) crises can lead to acute decompensation requiring extracorporeal membrane oxygenation (ECMO) support, including extracorporeal cardiopulmonary resuscitation (eCPR). We evaluated outcomes for pediatric PH patients requiring ECMO. A single-institution retrospective review of pediatric PAH patients with World Symposium on PH (WSPH) groups 1 and 3 requiring ECMO cannulation from 2010 through 2022 (n = 20) was performed. Primary outcome was survival to hospital discharge. Secondary outcomes were survival to decannulation and 1-year survival. Of 20 ECMO patients, 16 (80%) survived to decannulation and 8 (40%) survived to discharge and 1 year follow up. Of three patients who had two ECMO runs; none survived. There were five patients who had eCPR for the first run; one survived to discharge. The univariate logistic regression model showed that venovenous ECMO was associated with better survival to hospital discharge than venoarterial ECMO, (OR: 0.12, 95% CI: 0.01-0.86, p = 0.046). PH medications (administered before, during, or after ECMO) were not associated with survival to discharge. For children with decompensated PAH requiring ECMO, mortality rate is high, and management is challenging. While VA ECMO is the main configuration for decompensated PH, VV ECMO could be considered if there is adequate ventricular function, presence of a systemic to pulmonary shunt, or an intercurrent treatable illness to improve survival to discharge. A multidisciplinary approach with requisite expertise should be utilized on a case-by-case basis until more reliable data is available to predict outcomes.

Notch Signaling Is Associated with Pulmonary Fibrosis in Patients with Pigeon Breeder's Lung by Regulating Oxidative Stress

This study explored the molecular mechanism underlying the association of Notch signaling and oxidative stress with the occurrence of pulmonary fibrosis in patients with pigeon breeder's lung (PBL). Rat models of fibrotic PBL were constructed with freeze-dried protein powder, and the animals were divided into the control (intratracheal instillation of normal saline; n = 9), M (PBL model; intratracheal instillation of freeze-dried protein powder; n = 9), and M + D (PBL+ the Notch inhibitor DAPT; n = 9) groups. Immunohistochemistry was employed to observe the protein levels of pathway factors and α-SMA, and the levels of ROS, GSH-PX, SOD, and MDA were observed using ELISA. To verify the results of the animal experiment, cytological models were constructed. The M group and the M + D group had significantly increased α-SMA levels (P < 0.05). Although both groups had significantly higher key protein levels in the Notch channel, the M + D group had significantly lower levels relative to the M group (P < 0.05). Oxidative stress products were examined, and the levels of MDA and ROS were significantly increased, while those of GSH-PX and SOD were significantly decreased in the M and M + D groups as compared to the control, but the M group and the M + D group significantly differed (P <  0.05). These findings were further validated by the cytological experiment. Notch signaling is associated with pulmonary fibrosis in PBL by regulating cellular oxidative stress, and inhibiting this pathway can slow down pulmonary fibrosis progression.

Comparison of Different Treatments of Persistent Pulmonary Hypertension of the Newborn: A Systematic Review and Network Meta-Analysis

OBJECTIVES

Persistent pulmonary hypertension of the newborn (PPHN) is a life-threatening disease. Despite being considered the gold standard treatment scheme, inhaled nitric oxide (iNO) is not readily available in settings with limited resources. Therefore, in recent years, research on related drugs is being actively pursued. Herein, we aimed to use random-effects network meta-analysis to evaluate the efficacy and associated mortality of different PPHN therapies.

DATA SOURCES

We electronically searched the PubMed, Embase, and Cochrane Library for data up to January 27, 2023.

STUDY SELECTION

Randomized controlled trials involving neonates with PPHN assessing efficacy and mortality of various treatments.

DATA EXTRACTION

Details of study population, treatments, and outcomes were extracted.

DATA SYNTHESIS

Direct pairwise comparisons and a network meta-analysis was performed under random effects. The ranking probability was further assessed based on the surface under the cumulative ranking curve (SUCRA). We analyzed 23 randomized clinical trials involving 902 newborns with PPHN. Sixteen different treatment strategies were compared with each other and conventional therapy (CON). A median concentration of 10-20 parts per million (ppm) iNO (MNO) coupled with sildenafil orally administered at a dose of 1-3 mg/kg/dose every 6-8 hours (OSID) demonstrated the best efficacy (MNO + OSID vs. CON: odds ratio [OR] = 27.53, 95% CI, 2.36-321.75; SUCRA = 0.818, ranking first; moderate quality). OSID combined with milrinone administered IV also performed well in terms of efficacy (OSID + milrinone vs. CON: OR = 25.13, 95% CI = 1.67-377.78; SUCRA = 0.811, ranking second; low quality) and mortality reduction (CON vs. OSID + milrinone: OR = 25.13, 95% CI = 1.67-377.78; SUCRA = 0.786, ranking last; low quality).

CONCLUSIONS

MNO + OSID is the most effective PPHN treatment. If iNO is not available, OSID + milrinone is preferred.

Acute respiratory failure due to pulmonary exacerbation in children with cystic fibrosis admitted in a pediatric intensive care unit: outcomes and factors associated with mortality

BACKGROUND

Children with advanced pulmonary disease due to cystic fibrosis (CF) are at risk of acute respiratory failure due to pulmonary exacerbations leading to their admission to pediatric intensive care units (PICU). The objectives of this study were to determine short and medium-term outcomes of children with CF admitted to PICU for acute respiratory failure due to pulmonary exacerbation and to identify prognosis factors.

METHODS

This retrospective monocentric study included patients less than 18 years old admitted to the PICU of a French university hospital between 2000 and 2020. Cox proportional hazard regression methods were used to determine prognosis factors of mortality or lung transplant.

RESULTS

Prior to PICU admission, the 29 patients included (median age 13.5 years) had a severe lung disease (median Forced Expiratory Volume in 1 s percentage predicted at 29%). Mortality rates were respectively 17%, 31%, 34%, 41% at discharge and at 3, 12 and 36 months post-discharge. Survival rates free of lung transplant were 34%, 32%, 24% and 17% respectively. Risk factors associated with mortality or lung transplant using the univariate analysis were female sex and higher pCO2 and chloride levels at PICU admission, and following pre admission characteristics: home respiratory and nutritional support, registration on lung transplant list and Stenotrophomonas Maltophilia bronchial colonization.

CONCLUSION

Children with CF admitted to PICU for acute respiratory failure secondary to pulmonary exacerbations are at high risk of death, both in the short and medium terms. Lung transplant is their main chance of survival and should be considered early.

The evaluation of the SMAD1 rs1016792 polymorphism and gene expression on pulmonary hypertension due to congenital heart disease in children: a preliminary study

Smad Family Member (SMAD), a protein family responsible for transducing the signal induced by TGF-β into the nucleus, is thought to play a role in the pathology of many heart diseases. Therefore, we aimed to evaluate the influence of the SMAD1 rs1016792 polymorphism and gene expression on pulmonary arterial hypertension (PAH) due to congenital heart disease (CHD) in children. A total of 90 children, 45 of whom were PAH-CHD children and 45 healthy children, were included in the study. Patients were selected from those who were diagnosed and followed in the Department of Pediatric Cardiology.The SMAD1 rs1016792 genotyping and expression analysis was performed using a real-time polymerase chain reaction (RT-PCR)-based system. It was determined that the left ventricular end-diastolic diameter (LVEDD) value was lower in the patient group than in the control group, while the pulmonary artery pressure (PAP) value was higher in the patient group than in the control group. When the SMAD1 gene expression level was examined, a statistically significant difference was found between the patient and control groups. Patients had decreased SMAD1 expression compared to controls (p˂0.001). We found no significant difference between the patient and control groups in terms of SMAD1 rs1016792 genotype distribution or allele frequency (p > 0.05). There was no difference between genotype distribution and SMAD1 expression levels in the groups. In this study, we showed for the first time that SMAD1 expression is decreased in children with PAH-CHD. These results will be a preliminary step toward understanding the role of SMAD1 in the etiopathogenesis of CHD.

Association and risk factors of pediatric pulmonary hypertension with obstructive sleep apnea: A national study utilizing the Kids' Inpatient Database (KID)

STUDY OBJECTIVE

Assess the prevalence of and risk factors for pediatric pulmonary hypertension (PH) in the 2016 Kids' Inpatient Database (KID), including obstructive sleep apnea (OSA) and obesity.

METHODS

Retrospective cross-sectional cohort study utilizing 6,081,132 weighted pediatric discharges from the 2016 KID. Study variables included age, length of stay, mortality, gender, hospital region, primary payer, race, median household income for patient's ZIP code, OSA, central sleep apnea (CSA), obesity, Down syndrome, sickle cell disease (SCD), thalassemia, congenital heart disease (CHD), hypertension, asthma and chronic lung disease of prematurity (CLDP). PH was the primary outcome of interest. Bivariate and multivariable logistic regression models were utilized with odds ratios and 95 % confidence intervals.

RESULTS

The mean age was 3.76 years, the mean hospital length of stay was 3.85 days, 48.9 % were male, 52.6 % had government health insurance, 51.0 % were White, 16.1 % were Black, 21.1 % were Hispanic, 5.0 % were Asian or Pacific Islander, 0.80 % were Native American and 6.1 % identified as "other". The prevalence of PH was 0.21 % (12,777 patients). There were 37,631 patients with OSA and the prevalence of PH among this cohort was 3.3 %, over 10x greater than the overall prevalence of PH in the 2016 KID (0.21 %). Risk factors associated with PH included CLDP, CHD, Down syndrome, asthma, OSA, CSA, hypertension, SCD, obesity, race/ethnicity, government insurance, age, male gender (p < 0.0001), and hospital region (p = 0.0002).

CONCLUSIONS

Several risk factors were independently associated with PH, such as OSA, CSA, obesity, asthma, and insurance status. Prospective multi-institutional studies are needed to assess the relationships between these risk factors, severity metrics, and causative links in the development of PH; in addition to identifying children with OSA who are most likely to benefit from cardiopulmonary screening prior to adenotonsillectomy.

LEVEL OF EVIDENCE

Level III.

Real-world evidence for beneficial effects of dipyrone in 4,278 patients with pulmonary hypertension - Analysis of the risk of ventilation, hospitalization, and agranulocytosis

INTRODUCTION

Dipyrone has been used as an analgesic for a century, but recently was proposed as a novel therapeutic strategy for the prevention and therapy of pulmonary hypertension (PH). The aim of this study was to analyze whether the risk for ventilation procedures and hospitalization was lower among patients with PH who used dipyrone compared to subjects who did not use dipyrone.

MATERIALS AND METHODS

Initially, patients with PH were retrieved from the TriNetX database, whereby subjects who used dipyrone were assigned to cohort I, and cohort II was formed by those individuals who did not use dipyrone. Both cohorts were matched for several variables. The outcomes were requirement for ventilation procedures and hospital admission, whereby the time window to record events was 5 years after diagnosis of PH. Subsequently, risk analysis was carried out, and risk ratio (RR) and odds ratio (OR) were calculated. In addition, the risk of agranulocytosis was determined for both cohorts.

RESULTS

Out of 741,875 individuals diagnosed with PH 4,282 and 737,593 patients were assigned to the cohorts I and II. After matching, each cohort accounted for 4,278 individuals. Among the cohorts I and II 10 and 187 individuals required ventilation procedures. The according risks of 0.2% vs. 4.4% were significantly different (p < 0.0001; Log-Rank test). RR and OR were 0.053 and 0.051. Within the cohorts I and II 10 and 1,195 subjects required hospital admission. The risks of hospitalization of 0,4% vs. 27.9% differed significantly (p < 0.0001). RR and OR were 0.016 and 0.012. Among the cohorts I and II 47 and 66 individuals were diagnosed with agranulocytosis, whereby no significance was found (p > 0.05).

CONCLUSIONS

The risk for ventilation measures and hospitalization among patients with PH was found to be significantly lower when dipyrone was used. Even though the underlying mechanisms remain unknown to date, they are supposedly mediated by an active metabolite of dipyrone. The obtained results appear to be promising for patients suffering from PH. Hence, the present study may encourage further research.

Tadalafil Nanoemulsion Mists for Treatment of Pediatric Pulmonary Hypertension via Nebulization

Oral tadalafil (TD) proved promising in treating pediatric pulmonary arterial hypertension (PAH). However, to ensure higher efficacy and reduce the systemic side effects, targeted delivery to the lungs through nebulization was proposed as an alternative approach. This poorly soluble drug was previously dissolved in nanoemulsions (NEs). However, the formulations could not resist aqueous dilution, which precluded its dilution with saline for nebulization. Thus, the current study aimed to modify the previous systems into dilutable TD-NEs and assess their suitability for a pulmonary application. In this regard, screening of various excipients was conducted to optimize the former systems; different formulations were selected and characterized in terms of physicochemical properties, nebulization performance, stability following sterilization, and biocompatibility. Results showed that the optimal system comprised of Capmul-MCM-EP:Labrafac-lipophile (1:1) (w/w) as oil, Labrasol:Poloxamer-407 (2:1) (w/w) as surfactant mixture (S_mix) and water. The optimum formulation P2_TD resisted aqueous dilution, exhibited reasonable drug loading (2.45 mg/mL) and globule size (25.04 nm), acceptable pH and viscosity for pulmonary administration, and could be aerosolized using a jet nebulizer. Moreover, P2_TD demonstrated stability following sterilization and a favorable safety profile confirmed by both in-vitro and in-vivo toxicity studies. These favorable findings make P2_TD promising for the treatment of pediatric PAH.

Using real-world data in pediatric clinical trials: Lessons learned and future applications in studies of persistent pulmonary hypertension of the newborn

Persistent pulmonary hypertension of the newborn (PPHN) is a complication of term birth, characterized by persistent hypoxemia secondary to failure of normal postnatal reduction in pulmonary vascular resistance, with potential for short- and long-term morbidity and mortality. The primary pharmacologic goal for this condition is reduction of the neonate's elevated pulmonary vascular resistance with inhaled nitric oxide, the only approved treatment option. Various adjunctive, unapproved therapeutics have been trialed with mixed results, likely related to challenges with recruiting the full, intended patient population into clinical studies. Recently, real-world data and subsequent derived evidence have been utilized to improve the efficiency of various pediatric clinical trials. We aim to provide recent perspectives regarding the use of real-world data in the planning and execution of pediatric clinical trials and how this may facilitate more streamlined assessment of future therapeutics for the treatment of PPHN and other neonatal conditions.

Explainable machine learning models for predicting 30-day readmission in pediatric pulmonary hypertension: A multicenter, retrospective study

Background

Short-term readmission for pediatric pulmonary hypertension (PH) is associated with a substantial social and personal burden. However, tools to predict individualized readmission risk are lacking. This study aimed to develop machine learning models to predict 30-day unplanned readmission in children with PH.

Methods

This study collected data on pediatric inpatients with PH from the Chongqing Medical University Medical Data Platform from January 2012 to January 2019. Key clinical variables were selected by the least absolute shrinkage and the selection operator. Prediction models were selected from 15 machine learning algorithms with excellent performance, which was evaluated by area under the operating characteristic curve (AUC). The outcome of the predictive model was interpreted by SHapley Additive exPlanations (SHAP).

Results

A total of 5,913 pediatric patients with PH were included in the final cohort. The CatBoost model was selected as the predictive model with the greatest AUC for 0.81 (95% CI: 0.77–0.86), high accuracy for 0.74 (95% CI: 0.72–0.76), sensitivity 0.78 (95% CI: 0.69–0.87), and specificity 0.74 (95% CI: 0.72–0.76). Age, length of stay (LOS), congenital heart surgery, and nonmedical order discharge showed the greatest impact on 30-day readmission in pediatric PH, according to SHAP results.

Conclusions

This study developed a CatBoost model to predict the risk of unplanned 30-day readmission in pediatric patients with PH, which showed more significant performance compared with traditional logistic regression. We found that age, LOS, congenital heart surgery, and nonmedical order discharge were important factors for 30-day readmission in pediatric PH.