Growth in children with pulmonary arterial hypertension: a longitudinal retrospective multiregistry study

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.

Approaches to nutrition and feeding in congenital diaphragmatic hernia

In patients with congenital diaphragmatic hernia1, nutrition can represent a challenge both in the short and long term. Its failure to resolve can have a significant impact on multiple aspects of the lives of patients with congenital diaphragmatic hernia (CDH), ranging from lung function to neurodevelopment. In this review, we will describe the causes of nutritional problems in patients with CDH, their consequences, and possible strategies to address them.

Creating a digital approach for promoting physical activity in pediatric pulmonary hypertension: A framework for future interventions

Children with pulmonary hypertension (PH) often demonstrate limited exercise capacity. Data support exercise as an effective nonpharmacologic intervention among adults with PH. However, data on exercise training in children and adolescents are limited, and characteristics of the optimal exercise program in pediatric PH have not been identified. Exercise programs may have multiple targets, including muscle deficits which are associated with exercise limitations in both adult and pediatric PH. Wearable accelerometer sensors measure physical activity volume and intensity in the naturalistic setting and can facilitate near continuous data transfer and bidirectional communication between patients and the study team when paired with informatics tools during exercise interventions. To address the knowledge gaps in exercise training in pediatric PH, we designed a prospective, single arm, nonrandomized pilot study to determine feasibility and preliminary estimates of efficacy of a 16-week home exercise intervention, targeting lower extremity muscle mass and enriched by wearable mobile health technology. The exercIse Training in pulmONary hypertEnsion (iTONE) trial includes (1) semistructured exercise prescriptions tailored to the participant's baseline level of activity and access to resources; (2) interval goal setting fostering self-efficacy; (3) real time monitoring of activity via wearable devices; (4) a digital platform enabling communication and feedback between participant and study team; (5) multiple avenues to assess participant safety. This pilot intervention will provide information on the digital infrastructure needed to conduct home-based exercise interventions in PH and will generate important preliminary data on the effect of exercise interventions in youth with chronic cardiorespiratory conditions to power larger studies in the future.

Growing up with Idiopathic Pulmonary Arterial Hypertension: An Arduous Journey

Idiopathic pulmonary arterial hypertension (IPAH) is an uncommon and severe disease. We report the case of a 7-year-old boy investigated for cardiac murmur and exercise intolerance. Pulmonary hypertension (PH) was suspected at clinical examination and confirmed by echocardiography and cardiac catheterization. This case of pulmonary hypertension was classified as idiopathic given the negative etiological investigation. Vasoreactive testing with oxygen and nitric oxide was negative. Therefore, treatment with sildenafil (1.4 mg/kg/d) and bosentan (3 mg/kg/d) was initiated. This allowed the stabilization of, but not a decrease in, pulmonary artery pressure for the next 5 years, during which the patient's quality of life was significantly reduced. At a later follow-up, the estimated pulmonary pressure was found to have increased and become supra-systemic, with a consequent deterioration in the child's condition. This led to the decision to enter him into a clinical trial that is still ongoing. Idiopathic pulmonary arterial hypertension is a severe disease that can present with non-specific symptoms, such as asthenia and exercise limitation, which are important not to trivialize. The disease is associated with significantly decreased quality of life in affected children and carries a high burden in terms of mortality and morbidity. The current knowledge about IPAH in children is reviewed, with a particular focus on the future prospects for its treatment and the related quality of life of patients.

Idiopathic Pulmonary Arterial Hypertension in Paediatrics Represents Still a Serious Challenge: A Case Series Study

INTRODUCTION

Paediatric pulmonary hypertension (PH) represents a heterogeneous illness that is responsible for high morbidity and mortality if left without treatment. Idiopathic pulmonary arterial hypertension (IPAH) is a subtype of PAH rarely seen in paediatrics. Limited long-term data are available.

METHODS

Over a period of 20 years, 10 paediatric patients were enrolled at two tertiary centres. Their clinical, echocardiographic, and right heart catheterisation (RHC) features and outcome were evaluated.

RESULTS

The mean age at first diagnosis was 5.7 ± 5.7 years. The age at the last follow-up was 12.4 ± 6.1 years. The average follow-up was 6.6 ± 0.8 years. There was a female prevalence of 60% (p < 0.05) in this case series. Regarding the NYHA functional class, 80% of IPAH subjects were in class III or IV. The mean saturation was 91 ± 5%. In this regard, 70% of the patients were on a combination of three drugs, with sildenafil (90%) included. On echocardiography, longitudinal right ventricular contractility (TAPSE) was slightly reduced (13.4 ± 2.6 mm), whilst RVSP was severely elevated (101 ± 19 mmHg). The RHC data showed that mPAP was 61.8 ± 23.1 mmHg (p = 0.0017 with RVSP on echocardiography), mRAP was 10.7 ± 3.8 mmHg, CI was 2.6 ± 1 L·min-1·m-2, PVRi was 16.8 ± 12.6 WU·m2, and SVO2 was 63.6 ± 14.8%. Regarding the outcome, two male IPAH patients (20%) died, and 50% underwent lung transplant or were on transplant assessment or already on the waiting list for lung transplantation. One patient underwent a ductus arteriosus stenting (reverse Potts shunt) and another underwent atrial septostomy and stenting.

CONCLUSIONS

Notwithstanding the progress in medical therapy, IPAH continues to represent a serious challenge, particularly in the paediatric population, with the need for lung transplantation and significant mortality.

Skeletal muscle deficits are associated with worse exercise performance in pediatric pulmonary hypertension

BACKGROUND

Skeletal muscle deficits are associated with worse exercise performance in adults with pulmonary hypertension (PH) but the impact is poorly understood in pediatric PH.

OBJECTIVE

To study muscle deficits, physical inactivity, and performance on cardiopulmonary exercise test (CPET) and exercise cardiac magnetic resonance (eCMR) in pediatric PH.

METHODS

Youth 8-18 years participated in a prospective, cross-sectional study including densitometry (DXA) for measurement of leg lean mass Z-score (LLMZ), handheld dynamometer with generation of dominant and non-dominant handgrip Z-scores, Physical Activity Questionnaire (PAQ), CPET, and optional eCMR. CPET parameters were expressed relative to published reference values. CMR protocol included ventricular volumes and indexed systemic flow at rest and just after supine ergometer exercise. Relationships between LLMZ, PAQ score, and exercise performance were assessed by Pearson correlation and multiple linear regression.

RESULTS

There were 25 participants (13.7 ± 2.8 years, 56% female, 64% PH Group 1, 60% functional class I); 12 (48%) performed both CPET and eCMR. Mean LLMZ (-0.96 ± 1.14) was associated with PAQ score (r = 50, p = 0.01) and with peak oxygen consumption (VO₂) (r = 0.74, p = < 0.001), VO₂ at anaerobic threshold (r = 0.65, p < 0.001), and peak work rate (r = 0.64, p < 0.01). Higher handgrip Z-scores were associated with better CPET and eCMR performance. On regression analysis, LLMZ and PAQ score were positively associated with peak VO₂, while handgrip Z-score and PAQ score were positively associated with peak work rate.

CONCLUSION

Muscle mass and strength are positively associated with exercise performance in pediatric PH. Future studies should determine the effect of rehabilitation programs on muscle properties and exercise performance.

Prognostic biomarkers in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease of the pulmonary vasculature. Despite the introduction of targeted therapies, prognosis remains poor. In pediatric PAH, reliable prognostic biomarkers are needed to inform clinicians on disease progression and risk of mortality, in order to be able to assess the need for escalation of medical therapy, consider surgical options such as Pott's shunt and listing for (heart)-lung transplantation. This review provides an overview of prognostic biomarkers that are considered to carry potential for the clinical management of pediatric PAH. These include conventional physiological biomarkers [resting heart rate, heart rate variability (HRV), a child's growth], biomarkers of functional status [World Health Organization functional class, 6-minute walk distance (6MWD), parameters derived from cardiopulmonary exercise testing (CPET), daily physical activity level], electrocardiographic biomarkers, circulating serum biomarkers (natriuretic peptides, uric acid, neurohormones, inflammatory markers, and novel circulating biomarkers), and multiple hemodynamic biomarkers and imaging biomarkers [echocardiography and cardiac magnetic resonance (CMR)]. In recent years, many potential prognostic biomarkers have become available for the management of PAH in children. As the available prognostic biomarkers reflect different aspects of the disease process and functional implications, a multi-marker approach appears the most useful for guiding therapy decisions and improve outcome in pediatric PAH.

Marked skeletal muscle deficits are associated with 6-minute walk distance in paediatric pulmonary hypertension

BACKGROUND

Poor growth is common in children with pulmonary hypertension; however, skeletal muscle deficits have not been described and the association between muscle deficits and functional status is unknown.

METHODS

Patients aged 8-18 years with pulmonary hypertension (diagnostic Groups 1, 2, or 3) and World Health Organization functional class I or II underwent dual-energy absorptiometry to measure leg lean mass Z-score (a surrogate for skeletal muscle). Muscle strength was assessed using dynamometry. Physical activity questionnaires were administered. Clinical data, including 6-minute walk distance, were reviewed. Relationships between skeletal muscle, physical activity score, and 6-minute walk distance were assessed by correlations and linear regression.

RESULTS

Sixteen patients (12.1 ± 3.2 years, 50% female, 56% Group 1, 56% functional class II) were enrolled. Leg lean mass Z-score was significantly less than reference data (-1.40 ± 1.12 versus 0.0 ± 0.9, p < 0.001) and worse in those with functional class II versus I (-2.10 ± 0.83 versus -0.50 ± 0.73, p < 0.01). Leg lean mass Z-score was positively associated with right ventricular systolic function by tricuspid annular plane systolic Z-score (r = 0.54, p = 0.03) and negatively associated with indexed pulmonary vascular resistance (r = -0.78, p < 0.001). Leg lean mass Z-score and forearm strength were positively associated with physical activity score. When physical activity score was held constant, leg lean mass Z-score independently predicted 6-minute walk distance (R2 = 0.39, p = 0.03).

CONCLUSIONS

Youth with pulmonary hypertension demonstrate marked skeletal muscle deficits in association with exercise intolerance. Future studies should investigate whether low leg lean mass is a marker of disease severity or an independent target that can be improved.

Pulmonary hypertension in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a major complication in prematurely born infants. Pulmonary hypertension (PH) associated with BPD (BPD-PH) is characterized by alveolar diffusion impairment, abnormal vascular remodeling, and rarefication of pulmonary vessels (vascular growth arrest), which lead to increased pulmonary vascular resistance and right heart failure. About 25% of infants with moderate to severe BPD develop BPD-PH that is associated with high morbidity and mortality. The recent evolution of broader PH-targeted pharmacotherapy in adults has opened up new treatment options for infants with BPD-PH. Sildenafil became the mainstay of contemporary BPD-PH therapy. Additional medications, such as endothelin receptor antagonists and prostacyclin analogs/mimetics, are increasingly being investigated in infants with PH. However, pediatric data from prospective or randomized controlled trials are still sparse. We discuss comprehensive diagnostic and therapeutic strategies for BPD-PH and briefly review the relevant differential diagnoses of parenchymal and interstitial developmental lung diseases. In addition, we provide a practical framework for the management of children with BPD-PH, incorporating the modified definition and classification of pediatric PH from the 2018 World Symposium on Pulmonary Hypertension, and the 2019 EPPVDN consensus recommendations on established and newly developed therapeutic strategies. Finally, current gaps of knowledge and future research directions are discussed. IMPACT: PH in BPD substantially increases mortality. Treatment of BPD-PH should be conducted by an interdisciplinary team and follow our new treatment algorithm while still kept tailored to the individual patient. We discuss recent developments in BPD-PH, make recommendations on diagnosis, monitoring and treatment of PH in BPD, and address current gaps of knowledge and potential research directions. We provide a practical framework, including a new treatment algorithm, for the management of children with BPD-PH, incorporating the modified definition and classification of pediatric PH (2018 WSPH) and the 2019 EPPVDN consensus recommendations on established and newly developed therapeutic strategies for BPD-PH.

Pulmonary hypertension and myocardial function in infants and children with Down syndrome

Down Syndrome (DS) is the most common chromosomal abnormality of live born babies. Individuals with DS are at increased risk of cardiopulmonary morbidities in the early neonatal period, infancy and childhood that manifest with elevated pulmonary arterial pressures and altered myocardial performance. Pulmonary hypertension (PH) during the early neonatal period remains under-recognised in this population. PH may occur with or without a congenital heart defect in children with DS and is more common than in the general population. Early detection and continued screening of PH throughout infancy and childhood for these at-risk children is crucial for prompt intervention and potential prevention of long-term sequelae on cardiac function. This review summarises the main physiological concepts behind the mechanisms of PH in children with DS and provides a summary of the current available literature on PH and its impact on myocardial performance.

Children and Adolescents with Pulmonary Arterial Hypertension: Baseline and Follow-Up Data from the Polish Registry of Pulmonary Hypertension (BNP-PL)

We present the results from the pediatric arm of the Polish Registry of Pulmonary Hypertension. We prospectively enrolled all pulmonary arterial hypertension (PAH) patients, between the ages of 3 months and 18 years, who had been under the care of each PAH center in Poland between 1 March 2018 and 30 September 2018. The mean prevalence of PAH was 11.6 per million, and the estimated incidence rate was 2.4 per million/year, but it was geographically heterogeneous. Among 80 enrolled children (females, n = 40; 50%), 54 (67.5%) had PAH associated with congenital heart disease (CHD-PAH), 25 (31.25%) had idiopathic PAH (IPAH), and 1 (1.25%) had portopulmonary PAH. At the time of enrolment, 31% of the patients had significant impairment of physical capacity (WHO-FC III). The most frequent comorbidities included shortage of growth (n = 20; 25%), mental retardation (n = 32; 40%), hypothyroidism (n = 19; 23.8%) and Down syndrome (n = 24; 30%). The majority of children were treated with PAH-specific medications, but only half of them with double combination therapy, which improved after changing the reimbursement policy. The underrepresentation of PAH classes other than IPAH and CHD-PAH, and the geographically heterogeneous distribution of PAH prevalence, indicate the need for building awareness of PAH among pediatricians, while a frequent coexistence of PAH with other comorbidities calls for a multidisciplinary approach to the management of PAH children.

Paediatric pulmonary arterial hypertension: updates on definition, classification, diagnostics and management

Paediatric pulmonary arterial hypertension (PAH) shares common features of adult disease, but is associated with several additional disorders and challenges that require unique approaches. This article discusses recent advances, ongoing challenges and distinct approaches for the care of children with PAH, as presented by the Paediatric Task Force of the 6th World Symposium on Pulmonary Hypertension. We provide updates of the current definition, epidemiology, classification, diagnostics and treatment of paediatric PAH, and identify critical knowledge gaps. Several features of paediatric PAH including the prominence of neonatal PAH, especially in pre-term infants with developmental lung diseases, and novel genetic causes of paediatric PAH are highlighted. The use of cardiac catheterisation as a diagnostic modality and haemodynamic definitions of PAH, including acute vasoreactivity, are addressed. Updates are provided on issues related to utility of the previous classification system to reflect paediatric-specific aetiologies and approaches to medical and interventional management of PAH, including the Potts shunt. Although a lack of clinical trial data for the use of PAH-targeted therapy persists, emerging data are improving the identification of appropriate targets for goal-oriented therapy in children. Such data will likely improve future clinical trial design to enhance outcomes in paediatric PAH.

Analysis of short-term treatment with the phosphodiesterase type 5 inhibitor tadalafil on long bone development in young rats

Cyclic GMP (cGMP) is an important intracellular regulator of endochondral bone growth and skeletal remodeling. Tadalafil, an inhibitor of the phosphodiesterase (PDE) type 5 (PDE5) that specifically hydrolyzes cGMP, is increasingly used to treat children with pulmonary arterial hypertension (PAH), but the effect of tadalafil on bone growth and strength has not been previously investigated. In this study, we first analyzed the expression of transcripts encoding PDEs in primary cultures of chondrocytes from newborn rat epiphyses. We detected robust expression of PDE5 as the major phosphodiesterase hydrolyzing cGMP. Time-course experiments showed that C-type natriuretic peptide increased intracellular levels of cGMP in primary chondrocytes with a peak at 2 min, and in the presence of tadalafil the peak level of intracellular cGMP was 37% greater ( P < 0.01) and the decline was significantly attenuated. Next, we treated 1-mo-old Sprague Dawley rats with vehicle or tadalafil for 3 wk. Although 10 mg·kg^-1·day^-1 tadalafil led to a significant 52% ( P < 0.01) increase in tissue levels of cGMP and a 9% reduction ( P < 0.01) in bodyweight gain, it did not alter long bone length, cortical or trabecular bone properties, and histological features. In conclusion, our results indicate that PDE5 is highly expressed in growth plate chondrocytes, and short-term tadalafil treatment of growing rats at doses comparable to those used in children with PAH has neither obvious beneficial effect on long bone growth nor any observable adverse effect on growth plate structure and trabecular and cortical bone structure.

A Translational Model of Incomplete Catch-Up Growth: Early-Life Hypoxia and the Effect of Physical Activity

Advances in therapies have led to prolonged survival from many previously lethal health threats in children, notably among prematurely born babies and those with congenital heart disease. Evidence for catch‐up growth is common in these children, but in many cases the adult phenotype is never achieved. A translational animal model is required in which specific tissues can be studied over a reasonable time interval. We investigated the impact of postnatal hypoxia (HY) (12%O₂ (HY12) or 10% O₂ (HY10)) on growth in rats relative to animals raised in room air. Subgroups had access to running wheels following the HY period. Growth was fully compensated in adult HY12 rats but not HY10 rats. The results of this study indicate that neonatal hypoxia can be a useful model for the elucidation of mechanisms that mediate successful catch‐up growth following neonatal insults and identify the critical factors that prevent successful catch‐up growth.

Right ventricular function mirrors clinical improvement with use of prostacyclin analogues in pediatric pulmonary hypertension

Pulmonary hypertension (PH) causes significant morbidity and mortality in children due to right ventricular (RV) failure. We sought to determine the effect of prostacyclin analogues on RV function assessed by echocardiography in children with PH. We conducted a retrospective cohort study of children with PH treated with a prostacyclin analogue (epoprostenol or treprostinil) between January 2001 and August 2015 at our center. Data were collected before initiation of treatment (baseline) and at 1–3 and 6–12 months after. Protocolized echocardiogram measurements including tricuspid annular plane systolic excursion (TAPSE) and RV global longitudinal strain were made with blinding to clinical information. Forty-nine individuals (65% female), aged 0–29 years at the time of prostacyclin initiation were included. Disease types included pulmonary arterial hypertension (idiopathic [35%], heritable [2%], and congenital heart disease-associated [18%]), developmental lung disease (43%), and chronic thromboembolic PH (2%). Participants received intravenous (IV) epoprostenol (14%) and IV/subcutaneous (SQ) (67%) or inhaled (18%) treprostinil. Over the study period, prostacyclin analogues were associated with improvement in TAPSE (P = 0.007), RV strain (P < 0.001), and qualitative RV function (P = 0.037) by echocardiogram, and BNP (P < 0.001), functional class (P = 0.047) and 6-min walk distance (P = 0.001). TAPSE and strain improved at early follow up (P = 0.05 and P = 0.002, respectively) despite minimal RV pressure change. In children with PH, prostacyclin analogues are associated with an early and sustained improvement in RV function measured as TAPSE and strain as well as clinical markers of PH severity. RV strain may be a sensitive marker of RV function in this population.

Pediatric pulmonary arterial hypertension: on the eve of growing up

PURPOSE OF REVIEW

Current recommendations for diagnosis and treatment of pulmonary arterial hypertension (PAH) during childhood are expert opinion based, because of lacking pediatric data. In recent years, however, important pediatric data have emerged on PAH.

RECENT FINDINGS

PAH in children shows similarities as well as differences compared to adults. Neonates and children know specific clinical presentations and a hemodynamic profile that differs from adults with PAH. Children identified as acute vasodilator responders according to the criteria proposed for adults rather than the pediatric criteria have better outcome when treated with calcium channel blockers. For nonresponders, combination PAH-targeted therapy leads to improved outcome compared to monotherapy. In pediatric PAH, WHO functional class, N-terminal pro-brain natriuretic peptide and tricuspid annular plane systolic excursion were identified as surrogates for survival and therefore qualify to be treatment goals in a goal-oriented treatment strategy.

SUMMARY

In order to refine current pediatric treatment guidelines, data on efficacy of specific treatment regiments and strategies are needed. The recently validated composite endpoint of clinical worsening allows for trials that will provide these data. For the first time, evidence-based treatment goals have been identified that will allow for a goal-oriented treatment strategy. Furthermore, various prognostic predictors have been identified that may prove treatment goals in future.

Executive Summary of the American Heart Association and American Thoracic Society Joint Guidelines for Pediatric Pulmonary Hypertension

Although pulmonary hypertension (PH) contributes significantly to poor outcomes in diverse pediatric diseases, approaches toward the care of children with PH have been limited by the lack of consensus guidelines from experts in the field. In a joint effort from the American Heart Association and American Thoracic Society, a committee of experienced clinicians was formed to systematically identify, synthesize, and appraise relevant evidence and then to formulate evidence-based recommendations regarding the diagnosis and management of pediatric PH. This brief report is an executive summary of the officially approved guidelines developed by the committee, highlighting a few key recommendations regarding the care of children with PH. Guidelines and the rationale for grading the strength of each recommendation are included in the online supplement.