Long-term outcomes in children with pulmonary arterial hypertension treated with bosentan in real-world clinical settings

Invasive haemodynamics predict outcomes in paediatric pulmonary artery hypertension

BACKGROUND

Invasive haemodynamics are often performed for initiating and guiding pulmonary artery hypertension therapy. Little is known about the predictive value of invasive haemodynamic indices for long-term outcomes in children with pulmonary artery hypertension. We aimed to evaluate invasive haemodynamic data to help predict outcomes in paediatric pulmonary artery hypertension.

METHODS

Patients with pulmonary artery hypertension who underwent cardiac catheterisation (2006-2019) at a single centre were included. Invasive haemodynamic data from the first cardiac catheterisation and clinical outcomes were reviewed. The combined adverse outcome was defined as pericardial effusion (due to right ventricle failure), creation of a shunt for pulmonary artery hypertension (atrial septal defect or reverse Pott's shunt), lung transplant, or death.

RESULTS

Among 46 patients with a median [interquartile range (IQR)] age of 13.2 [4.1-44.7] months, 76% had CHD. Median mean pulmonary artery pressure was 37 [28-52] mmHg and indexed pulmonary vascular resistance was 6.2 [3.6-10] Woods units × m2. Median pulmonary artery pulsatility index was 4.0 [3.0-4.7] and right ventricular stroke work index was 915 [715-1734] mmHg mL/m2. After a median follow-up of 2.4 years, nine patients had a combined adverse outcome (two had a pericardial effusion, one underwent atrial level shunt, one underwent reverse Pott's shunt, and six died). Patients with an adverse outcome had higher systolic and mean pulmonary artery pressures, higher diastolic and transpulmonary pressure gradients, higher indexed pulmonary vascular resistance, higher pulmonary artery elastance, and higher right ventricular stroke work index (p < 0.05 each).

CONCLUSION

Invasive haemodynamics (especially mean pulmonary artery pressure and diastolic pressure gradient) obtained at first cardiac catheterisation in children with pulmonary artery hypertension predicts outcomes.

Long-term outcome of children with newly diagnosed pulmonary arterial hypertension: results from the global TOPP registry

BACKGROUND AND AIMS

The Tracking Outcomes and Practice in Pediatric Pulmonary Hypertension (TOPP) registry is a global network established to gain insights into the disease course and long-term outcomes of paediatric pulmonary arterial hypertension (PAH). Previously published cohorts in paediatric PAH are obscured by survival bias due to the inclusion of both prevalent (previously diagnosed) and incident (newly diagnosed) patients. The current study aims to describe long-term outcome and its predictors in paediatric PAH, exclusively of newly diagnosed patients.

METHODS AND RESULTS

Five hundred thirty-one children with confirmed pulmonary hypertension, aged ≥3 months and <18 years, were enrolled in the real-world TOPP registry at 33 centres in 20 countries, from 2008 to 2015. Of these, 242 children with newly diagnosed PAH with at least one follow-up visit were included in the current outcome analyses. During long-term follow-up, 42 (17.4%) children died, 9 (3.7%) underwent lung transplantation, 3 (1.2%) atrial septostomy, and 9 (3.7%) Potts shunt palliation (event rates: 6.2, 1.3, 0.4, and 1.4 events per 100 person-years, respectively). One-, three-, and five-year survival free from adverse outcome was 83.9%, 75.2%, and 71.8%, respectively.Overall, children with open (unrepaired or residual) cardiac shunts had the best survival rates. Younger age, worse World Health Organization functional class, and higher pulmonary vascular resistance index were identified as independent predictors of long-term adverse outcome. Younger age, higher mean right atrial pressure, and lower systemic venous oxygen saturation were specifically identified as independent predictors of early adverse outcome (within 12 months after enrolment).

CONCLUSION

This comprehensive analysis of survival from time of diagnosis in a large exclusive cohort of children newly diagnosed with PAH describes current-era outcome and its predictors.

Actigraphy methodology in the Kids Mod PAH trial: Physical activity as a functional endpoint in pediatric clinical trials

Pulmonary vasodilator treatment can improve hemodynamics, right ventricular function, symptoms, and survival in pediatric pulmonary hypertension (PH). However, clinical trial data are lacking due to many constraints. One major limitation is the lack of relevant trial endpoints reflective of hemodynamics or functional status in patients in whom standard exercise testing is impractical, unreliable, or not reproducible. The Kids Mod PAH trial (Mono- vs. Duo Therapy for Pediatric Pulmonary Arterial Hypertension) is an ongoing multicenter, Phase III, randomized, open-label, pragmatic trial to compare the safety and efficacy of first-line combination therapy (sildenafil and bosentan) to first-line monotherapy (sildenafil alone) in 100 pediatric patients with PH across North America. Investigators will measure participants' physical activity with a research-grade, wrist-worn actigraphy device at multiple time points as an exploratory secondary outcome. Vector magnitude counts per minute and activity intensity will be compared between the treatment arms. By directly and noninvasively measuring physical activity in the ambulatory setting, we aim to identify a novel, simple, inexpensive, and highly reproducible approach for quantitative assessment of exercise tolerance in pediatric PH. These data will increase the field's understanding of the effect of pulmonary vasodilator treatment on daily activity - a quantitative measure of functional status and wellbeing in pediatric PH and a potential primary outcome for future clinical trials in children with cardiopulmonary disorders.

Pharmacotherapy for Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia: Past, Present, and Future

Approximately 8-42% of premature infants with chronic lung disease of prematurity, bronchopulmonary dysplasia (BPD), develop pulmonary hypertension (PH). Infants with BPD-PH carry alarmingly high mortality rates of up to 47%. Effective PH-targeted pharmacotherapies are desperately needed for these infants. Although many PH-targeted pharmacotherapies are commonly used to treat BPD-PH, all current use is off-label. Moreover, all current recommendations for the use of any PH-targeted therapy in infants with BPD-PH are based on expert opinion and consensus statements. Randomized Control Trials (RCTs) are needed to determine the efficacy of PH-targeted treatments in premature infants with or at risk of BPD-PH. Prior to performing efficacy RCTs, studies need to be conducted to obtain pharmacokinetic, pharmacodynamic, and safety data for any pharmacotherapy used in this understudied and fragile patient population. This review will discuss current and needed treatment strategies, identify knowledge deficits, and delineate both challenges to be overcome and approaches to be taken to develop effective PH-targeted pharmacotherapies that will improve outcomes for premature infants with or at risk of developing BPD-PH.

Data-driven computational models of ventricular-arterial hemodynamics in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a complex disease involving increased resistance in the pulmonary arteries and subsequent right ventricular (RV) remodeling. Ventricular-arterial interactions are fundamental to PAH pathophysiology but are rarely captured in computational models. It is important to identify metrics that capture and quantify these interactions to inform our understanding of this disease as well as potentially facilitate patient stratification. Towards this end, we developed and calibrated two multi-scale high-resolution closed-loop computational models using open-source software: a high-resolution arterial model implemented using CRIMSON, and a high-resolution ventricular model implemented using FEniCS. Models were constructed with clinical data including non-invasive imaging and invasive hemodynamic measurements from a cohort of pediatric PAH patients. A contribution of this work is the discussion of inconsistencies in anatomical and hemodynamic data routinely acquired in PAH patients. We proposed and implemented strategies to mitigate these inconsistencies, and subsequently use this data to inform and calibrate computational models of the ventricles and large arteries. Computational models based on adjusted clinical data were calibrated until the simulated results for the high-resolution arterial models matched within 10% of adjusted data consisting of pressure and flow, whereas the high-resolution ventricular models were calibrated until simulation results matched adjusted data of volume and pressure waveforms within 10%. A statistical analysis was performed to correlate numerous data-derived and model-derived metrics with clinically assessed disease severity. Several model-derived metrics were strongly correlated with clinically assessed disease severity, suggesting that computational models may aid in assessing PAH severity.

Nonsurgical treatment of cerebral ischemia associated with ACTA2 cerebral arteriopathy: a case report and literature review

Mutations in ACTA2 gene can lead to multisystemic smooth muscle dysfunction, including cerebrovascular disease. Treatment strategies for this rare entity remain controversial, and patients are at increasing risk of neurological sequelae. We herein present the case of an 11-year-old boy previously diagnosed with an ACTA2 gene mutation who developed repetitive transient ischemic attacks and treated with bosentan, an oral endothelin receptor antagonist. Magnetic resonance imaging revealed bilateral, periventricular white matter T2 hyperintensities, and magnetic resonance angiography identified several abnormalities including fusiform dilatation in the proximal segments of internal cerebral arteries, together with followed by terminal segmental stenosis. The distal branches showed a markedly straightened course with no increase in lenticulostriate collaterals. Magnetic resonance imaging also revealed an increase in the number and size of large periventricular white matter lesions located in the left frontal lobe with the progression of ischemic symptoms. Instead of revascularization surgery, the administration of bosentan was started due to the high risk of perioperative ischemic sequelae. After bosentan initiation, the patient's repetitive episodes of cerebral ischemia ceased, and there has been no increase in the number of white matter lesions for 7 years. Bosentan might be beneficial for treating cerebral ischemia associated with ACTA2 cerebral arteriopathy by maintaining the dilatation of stenotic vessels and adequate systemic blood flow and should be considered before performing revascularization surgery.

Effects of exercise training on heart rate variability in children and adolescents with pulmonary arterial hypertension: a pilot study

Background

Pulmonary arterial hypertension (PAH) is often associated with cardiac autonomic dysfunction, and heart rate variability (HRV) as marker of cardiac autonomic function is even related to disease severity. Knowledge about the effects of physical activity on HRV is limited in these patients. We aimed to assess whether HRV parameters can be influenced by a supervised exercise training program and whether respective changes are related to levels of activity.

Methods

Six children and adolescents with moderate PAH (3 female, mean age 15.0±4.4 years; mean pulmonary to systemic arterial pressure ratio 0.5±0.2) performed supervised endurance and resistance training for 16 weeks. PAH-specific targeted medication remained unchanged during the study period. HRV was assessed before training and after 16 weeks of training by the use of ECG Move accelerometers. HRV indices included: standard deviation of normal-to-normal (NN) intervals (SDNN), square root of the mean of the sum of the squares of differences between successive NN-intervals (RMSSD), proportion of the number of pairs of successive normal-to-normal intervals that differ by more than 50 ms divided by total number of normal-to-normal interval (pNN50), and the Baevsky stress index (BSI) calculated by the histogram method.

Results

Before and after the training program, SDNN, RMSSD and pNN50 correlated with the level of physical activity. Mean values of SDNN, RMSSD and pNN50 did not change significantly due to the training program. Notably, activity level depending SDNN increased markedly after the exercise program (during activity +12.4%, at rest +6.6% and reclining +8.1%, Hedge's g of 0.28, 0.14 and 0.27, respectively). BSI decreased during activity due to the training program reflecting a reduction of stress level (Hedge's g -0.87 indicating an effect of clinical relevance).

Conclusions

According to the experience of this pilot study a workout program of 16 weeks revealed an activity level dependent effect on parameters of autonomic cardiac function in children and adolescents with PAH. This mechanism might contribute to the positive effects of exercise training in patients with PAH.

Treatment of pulmonary arterial hypertension in children

Pulmonary arterial hypertension (PAH) is a devastating illness causing already significant morbidity in childhood. Currently approved treatment options for children comprise the endothelin receptor antagonist bosentan, as well as the phosphodiesterase-5 inhibitor sildenafil. But PAH treatment has advanced significantly over the past decade, and new classes of targeted drug therapies, such as stimulators of the soluble guanylate cyclase (riociguat) or prostacyclin receptor agonists (selexipag), are currently evaluated regarding their efficacy and safety in children, in order to limit off-label use. Due to the different etiologies in children, such as PAH-CHD, there is no evidence that initial combination therapy in children is superior to a mono-therapy with respect to survival. Special attention should also be paid to the pharmacology of PAH drugs in children, which might be impacted by ontogeny or drug-drug-interactions. Therapeutic drug monitoring may be useful in pediatric patients. There is a clear need for more controlled studies of PAH medications, alone or in combination therapy in the pediatric age group. Data from clinical trials as well as from patient registries should be pooled to optimize drug development and evaluation, trial design, and evidence-based pharmacotherapy in pediatric patients with PAH. In this review, the current treatment options of pediatric PAH are summarized, and an overview of new treatment concepts, which are already evaluated in adults, is presented.

Systematic review and cost-effectiveness of bosentan and sildenafil as therapeutic drugs for pediatric pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare disease in children, with significant mortality. Because of the limited research on pediatric PAH, first, systematic review of related drugs is conducted, and then economic evaluation of PAH drug treatment programs is conducted, which to provide a reference for the choice of more cost-effective treatment options.

METHODS

The search includes electronic databases such as Pubmed, ScienceDirect, and Embase. Through inclusion and exclusion criteria, screen high-quality randomized controlled trials. We used TreeAge Pro 2011 software to construct the markov model, that to simulate the total medical cost and quality-adjusted life years (QALYs), and to calculate the incremental cost-effectiveness ratio. Sensitivity analysis of transfer probability, utility, and cost was carried out.

RESULTS

Incorporate two studies that meet the criteria, one compared the therapeutic effects of bosentan and placebo on pediatric PAH, the other compared therapeutic effects of sildenafil and placebo on pediatric PAH, both articles were of good quality. Compared with the sildenafil group (3.38QALYs and $161,120.14), the QALY of the bosentan treatment group (3.33QALYs and $257,411.29) was reduced by 0.05, and the cost increased by $96,291.15. The estimated improvement to quality of life and reduced costs result in an estimate of economic dominance for sildenafil over bosentan. This dominant result persisted probabilistic analyses.

CONCLUSIONS

Based on this model, a more cost-effective treatment drug for PAH in children is sildenafil.

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.

Parenteral Prostanoids in Pediatric Pulmonary Arterial Hypertension: Start Early, Dose High, Combine

Rationale

There are currently no data supporting specific dosing and weaning strategies for parenteral prostanoid therapy in children with pulmonary arterial hypertension (PAH).

Objectives

To describe the clinical practice of intravenous (IV) or subcutaneous (SC) prostanoid therapy in pediatric PAH and identify dosing strategies associated with favorable outcome.

Methods

From an international multicenter cohort of 275 children with PAH, 98 patients who received IV/SC prostanoid therapy were retrospectively analyzed.

Results

IV/SC prostanoids were given as monotherapy (20%) or combined with other PAH-targeted drugs as dual (46%) or triple therapy (34%). The median time-averaged dose was 37 ng/kg/min, ranging 2–136 ng/kg/min. During follow-up, IV/SC prostanoids were discontinued and transitioned to oral or inhaled PAH-targeted therapies in 29 patients. Time-dependent receiver operating characteristic analyses showed specific hemodynamic criteria at discontinuation of IV/SC prostanoids (mean pulmonary arterial pressure < 35 mm Hg and/or pulmonary vascular resistance index < 4.4 Wood units [WU]⋅m²) identified children with favorable long-term outcome after IV/SC prostanoid discontinuation, compared with patients who do not meet those criteria (P = 0.027). In the children who continued IV/SC prostanoids until the end of follow-up, higher dose (>25 ng/kg/min), early start after diagnosis, and combination with other PAH-targeted drugs were associated with better transplant-free survival.

Conclusions

Early initiation of IV/SC prostanoids, higher doses of IV/SC prostanoids, and combination with additional PAH-targeted therapy were associated with favorable outcome. Transition from IV/SC prostanoid therapy to oral or inhaled therapies is safe in the long term in selected children, identified by reaching hemodynamic criteria for durable IV/SC prostanoid discontinuation while on IV/SC prostanoid therapy.

In vivo assessment of a single adenine mutation in 5'UTR of Endothelin-1 gene in paediatric cases with severe pulmonary hypertension: an observational study

Objective

Endothelin-1 plays an important role in the pathogenesis of severe pulmonary hypertension. The + 139 ‘A’, adenine insertion variant in 5′UTR of edn1 gene has been reported to be associated with increased expression of Endothelin-1 in vitro. The aim of present study was to explore the association of this variant with the circulating levels of Endothelin-1 in vivo using archived DNA and plasma samples from 38 paediatric congenital heart disease (cyanotic and acyanotic) patients with severe pulmonary hypertension.

Results

The plasma Endothelin-1 levels were highly varied ranging from 1.63 to75.16 pg/ml. The + 139 ‘A’ insertion variant in 5′UTR of edn1 was seen in 8 out of 38 cases with only one acyanotic sample demonstrating homozygosity of inserted ‘A’ allele at + 139 site (4A/4A genotype). The plasma Endothelin-1 levels in children with homozygous variant 3A/3A genotype were comparable in cyanotic and acyanotic groups. Lone 4A/4A acyanotic sample had ET-1 levels similar to the median value of ET-1 associated with 3A/3A genotype and was absent in cyanotic group presumably due to deleterious higher ET-1 levels. The discussed observations, limited by the small sample size, are suggestive of homozygous adenine insertion variant posing a risk in cyanotic babies with Severe Pulmonary Hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05609-5.

Adverse drug event rates in pediatric pulmonary hypertension: a comparison of real-world data sources

Objective

Real-world data (RWD) are increasingly used for pharmacoepidemiology and regulatory innovation. Our objective was to compare adverse drug event (ADE) rates determined from two RWD sources, electronic health records and administrative claims data, among children treated with drugs for pulmonary hypertension.

Materials and Methods

Textual mentions of medications and signs/symptoms that may represent ADEs were identified in clinical notes using natural language processing. Diagnostic codes for the same signs/symptoms were identified in our electronic data warehouse for the patients with textual evidence of taking pulmonary hypertension-targeted drugs. We compared rates of ADEs identified in clinical notes to those identified from diagnostic code data. In addition, we compared putative ADE rates from clinical notes to those from a healthcare claims dataset from a large, national insurer.

Results

Analysis of clinical notes identified up to 7-fold higher ADE rates than those ascertained from diagnostic codes. However, certain ADEs (eg, hearing loss) were more often identified in diagnostic code data. Similar results were found when ADE rates ascertained from clinical notes and national claims data were compared.

Discussion

While administrative claims and clinical notes are both increasingly used for RWD-based pharmacovigilance, ADE rates substantially differ depending on data source.

Conclusion

Pharmacovigilance based on RWD may lead to discrepant results depending on the data source analyzed. Further work is needed to confirm the validity of identified ADEs, to distinguish them from disease effects, and to understand tradeoffs in sensitivity and specificity between data sources.

Update on Perioperative Pediatric Pulmonary Hypertension Management

Pediatric pulmonary hypertension is a disease that has many etiologies and can present anytime during childhood. Its newly revised hemodynamic definition follows that of adult pulmonary hypertension: a mean pulmonary artery pressure >20 mmHg. However, the pediatric definition stipulates that the elevated pressure must be present after the age of three months. The definition encompasses many different etiologies, and diagnosis often involves a combination of noninvasive and invasive testing. Treatment often is extrapolated from adult studies or based on expert opinion. Moreover, although general anesthesia may be required for pediatric patients with pulmonary hypertension, it poses certain risks. A thoughtful, multidisciplinary approach is needed to deliver excellent perioperative care.

Prognostic Value of Early Risk Stratification in Pediatric Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a life-threatening disease with risk stratification-based treatment strategy in adults. Although the risk factors have been studied individually in children, effective risk stratification is still lacking. We have tested the prognostic accuracy of pediatric PAH risk factors in our patient group.

PATIENTS AND METHODS

Records of 58 PAH patients treated between 1995 and 2019 were reviewed retrospectively. Median age at diagnosis was 4.2 years (range, 0.1-16.1 years), and follow-up was 5.4 years (range, 0.01-24.1 years). Data collected at diagnosis were demographics, World Health Organization functional class, evidence of right ventricular failure, and parameters of echocardiography and cardiac catheterization.

RESULTS

Mortality was 29% and 33% reached the composite endpoint. Patients with idiopathic PAH (n = 12) had increased risk of mortality compared with the congenital heart disease-associated PAH group (n = 32) (P = .0024). Neither the initial World Health Organization functional class staging nor the echocardiographic parameters significantly predicted the prognosis. The number of risk factors had no significant prognostic value either. In contrast, patients with higher pulmonary vascular resistance index (PVRI) had significantly increased risk (each 10 Wood units ⋅ m² increase in PVRI being associated with 49.1% higher hazard, P = .0048).

CONCLUSIONS

Survival analysis showed that PAH etiology might be an important determinant in pediatric PAH risk stratification. We confirmed that PVRI has predictive value in prognostic assessment. We could not establish the prognostic value of nonweighted single risk factors or their combination to predict pediatric PAH outcome due to the low sample size, but these results indicate that such studies are warranted.

Drug Treatment of Pulmonary Hypertension in Children

Pulmonary arterial hypertension (PAH) is a rare disease in infants and children that is associated with significant morbidity and mortality. The disease is characterized by progressive pulmonary vascular functional and structural changes resulting in increased pulmonary vascular resistance and eventual right heart failure and death. In many pediatric patients, PAH is idiopathic or associated with congenital heart disease and rarely is associated with other conditions such as connective tissue or thromboembolic disease. PAH associated with developmental lung diseases such as bronchopulmonary dysplasia or congenital diaphragmatic hernia is increasingly more recognized in infants and children. Although treatment of the underlying disease and reversal of advanced structural changes have not yet been achieved with current therapy, quality of life and survival have improved significantly. Targeted pulmonary vasodilator therapies, including endothelin receptor antagonists, prostacyclin analogs, and phosphodiesterase type 5 inhibitors have resulted in hemodynamic and functional improvement in children. The management of pediatric PAH remains challenging as treatment decisions depend largely on results from evidence-based adult studies and the clinical experience of pediatric experts. This article reviews the current drug therapies and their use in the management of PAH in children.

Predictors of operability in children with severe pulmonary hypertension associated with congenital heart disease

BACKGROUND

Pulmonary artery hypertension associated with congenital heart disease (PAH-CHD) occurs predominantly among patients with uncorrected CHD. Treatment of severe pediatric PAH-CHD remains a major intractability. This study evaluated the predictors and prognoses of children with PAH-CHD who underwent surgical correction.

METHODS

The data for 59 children with severe PAH-CHD who underwent surgical correction, with or without postoperative medication, between May 2011 and June 2015 at the Guangdong Provincial People's Hospital were analyzed retrospectively. A regression analysis, receiver-operating characteristic (ROC) curves, and Kaplan-Meier curves were used for survival analysis.

RESULTS

Fifty-nine children with severe PAH-CHD underwent heart catheterization and correction, with or without specific anti-PAH drugs postoperatively, were included in this study. The pulmonary pressure, heart function, and ending events were observed and median observation period was 49 ± 20 months. Twenty-eight patients (50%) received at least one additional anti-PAH drug after correction. The survival rate after 2 years was 91.5% (54/59); two patients were in a critical condition, and three were lost to follow-up. Twelve patients (29%) still received over one additional PAH-specific therapy at follow-up, whereas 42 (75%) had successfully stopped drug treatment. Two patients (3.5%) died and one underwent a second thoracotomy to remove the ventricular septal defect patch. Acute vasoreactivity test (AVT) criteria had limited efficacy in predicting pediatric PAH-CHD, whereas pulmonary vascular resistance (PVR) ≤ 6.65 Wood units (WU)/m or PVR/systemic vascular resistance (SVR) ≤ 0.39 during AVT indicated a good prognosis after surgical correction with an AUC of 98.3% (95% confidence interval [CI]: 96.0-100%), 98.4% (95% CI: 96.0-100%) sensitivity of 100%, 100% and specificity of 82.1%, 92.9%, respectively.

CONCLUSIONS

Although the criteria for positive AVT currently used are unsuitable for pediatric patients with PAH-CHD, PVR and PVR/SVR during AVT are excellent predictors of outcome in pediatric PAH-CHD. Surgery aided by anti-PAH drugs is an effective strategy and should be recommended for severe pediatric PAH-CHD with PVR ≤ 6.65 WU/m and PVR/SVR ≤ 0.39 after iloprost aerosol inhalation.

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.

Bosentan for Treatment of Pediatric Idiopathic Pulmonary Arterial Hypertension: State-of-the-Art

Idiopathic pulmonary arterial hypertension (IPAH) is a complex disease associated with progressive deterioration. Targeted therapy for IPAH has improved in the last several decades. However, there remain many challenges to current treatment of children with IPAH, including poor prognosis and a median survival of 0.8 years. Endothelin-1 (ET-1) appears to be a key mediator in the pathogenesis of IPAH, with elevated concentrations in the plasma. Bosentan, an endothelin receptor antagonist, has been confirmed in Food and Drug Administration (FDA) to effectively treat IPAH when administered in recent studies. This review focuses on related studies and advance of bosentan in the treatment of IPAH in children.

Impact of the Right Ventricular Sokolow-Lyon Index in Children with Idiopathic Pulmonary Arterial Hypertension

Right ventricular (RV) hypertrophy is regarded as the adaptation on chronic RV pressure load in pulmonary hypertension. As the RV Sokolow-Lyon index (RVSLI) is an electrocardiographic marker of RV hypertrophy, we hypothesized that RVSLI might be able to reflect RV pressure load. Therefore, the purpose of this study was to characterize the diagnostic impact of the RVSLI in children with idiopathic pulmonary arterial hypertension (IPAH) in order to assess disease severity and to evaluate its value for the prediction of worse outcome. Forty-two children (aged 3-17 years) with IPAH were included in this retrospective study. The follow-up after baseline examination was 59 ± 17 months. Receiver-operating characteristic (ROC) curves and Kaplan-Meier analysis were used to discriminate a cut-off value of RVSLI and to assess its predictive value regarding morbidity and mortality. In 12/42 patients (29%) severe cardiovascular events (defined as death, lung transplantation, or Potts shunt) were observed (time to event 20 ± 22 months). Patients with an event showed higher RVSLI values (3.6 ± 1.2 mV vs. 2.6 ± 1.6 mV; p < 0.05). ROC analysis discriminated an RVSLI of 2.1 as the best cut-off value (area under the ROC curve: 0.79, sensitivity: 0.91, specificity: 0.70, p < 0.05) to detect patients with high-risk PAH (mPAP/mSAP ratio > 0.75). Relative risk for a severe event with an index > 2.1 mV was 1.76 (95% CI 1.21-3.20). Relative risk for death with RVSLI > 2.1 mV was 2.01 (95% CI 1.61-4.80). Our study demonstrates a strong relationship between RVSLI and disease severity in children with IPAH. An RVSLI > 2.1 mV at the time of first diagnosis is a predictor for patients at risk for cardiac events. As an adjunct to the usual diagnostic assessment this parameter may therefore contribute to the initial prognostic estimation.

Intensive Care Mortality Prognostic Model for Pediatric Pulmonary Hypertension

OBJECTIVES

The disease burden and mortality of children with pulmonary hypertension are significantly higher than for the general PICU population. We aimed to develop a risk-adjustment tool predicting PICU mortality for pediatric pulmonary hypertension patients: the Pediatric Index of Pulmonary Hypertension Intensive Care Mortality score.

DESIGN

Retrospective analysis of prospectively collected multicenter pediatric critical care data.

SETTING

One-hundred forty-three centers submitting data to Virtual Pediatric Systems database between January 1, 2009, and December 31, 2015.

PATIENTS

Patients 21 years old or younger with a diagnosis of pulmonary hypertension.

INTERVENTIONS

Twenty-one demographic, diagnostic, and physiologic variables obtained within 12 hours of PICU admission were assessed for inclusion. Multivariable logistic regression with stepwise selection was performed to develop the final model. Receiver operating characteristic curves were used to compare the Pediatric Index of Pulmonary Hypertension Intensive Care Mortality score with Pediatric Risk of Mortality 3 and Pediatric Index of Mortality 2 scores.

MEASUREMENTS AND MAIN RESULTS

Fourteen-thousand two-hundred sixty-eight admissions with a diagnosis of pulmonary hypertension were included. Primary outcome was PICU mortality. Fourteen variables were selected for the final model: age, bradycardia, systolic hypotension, tachypnea, pH, FIO2, hemoglobin, blood urea nitrogen, creatinine, mechanical ventilation, nonelective admission, previous PICU admission, PICU admission due to nonsurgical cardiovascular disease, and cardiac arrest immediately prior to admission. The receiver operating characteristic curve for the Pediatric Index of Pulmonary Hypertension Intensive Care Mortality model (area under the curve = 0.77) performed significantly better than the receiver operating characteristic curves for Pediatric Risk of Mortality 3 (area under the curve = 0.71; p < 0.001) and Pediatric Index of Mortality 2 (area under the curve = 0.69; p < 0.001), respectively.

CONCLUSIONS

The Pediatric Index of Pulmonary Hypertension Intensive Care Mortality score is a parsimonious model that performs better than Pediatric Risk of Mortality 3 and Pediatric Index of Mortality 2 for mortality in a multicenter cohort of pediatric pulmonary hypertension patients admitted to PICUs. Application of the Pediatric Index of Pulmonary Hypertension Intensive Care Mortality model to pulmonary hypertension patients in the PICU might facilitate earlier identification of patients at high risk for mortality and improve the ability to prognosticate for patients and families.

Right ventricular stroke work correlates with outcomes in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary artery pressures (PAP) and pulmonary vascular resistance (PVR). Optimizing treatment strategies and timing for transplant remains challenging. Thus, a quantitative measure to predict disease progression would be greatly beneficial in treatment planning. We devised a novel method to assess right ventricular (RV) stroke work (RVSW) as a potential biomarker of the failing heart that correlates with clinical worsening. Pediatric patients with idiopathic PAH or PAH secondary to congenital heart disease who had serial, temporally matched cardiac catheterization and magnetic resonance imaging (MRI) data were included. RV and PA hemodynamics were numerically determined by using a lumped parameter (circuit analogy) model to create pressure-volume (P-V) loops. The model was tuned using optimization techniques to match MRI and catheterization derived RV volumes and pressures for each time point. RVSW was calculated from the corresponding P-V loop and indexed by ejection fraction and body surface area (RVSW_EF) to compare across patients. Seventeen patients (8 boys; median age = 9.4 years; age range = 4.4–16.3 years) were enrolled. Nine were clinically stable; the others had clinical worsening between the time of their initial matched studies and their most recent follow-up (mean time = 3.9 years; range = 1.1–8.0 years). RVSW_EF and the ratio of pulmonary to systemic resistance (Rp:Rs) values were found to have more significant associations with clinical worsening within one, two, and five years following the measurements, when compared with PVR index (PVRI). A receiver operating characteristic analysis showed RVSW_EF outperforms PVRI, Rp:Rs and ejection fraction for predicting clinical worsening. RVSW_EF correlates with clinical worsening in pediatric PAH, shows promising results towards predicting adverse outcomes, and may serve as an indicator of future clinical worsening.

CONTEMPORARY STRATEGY OF PULMONARY HYPERTENSION MANAGEMENT IN PEDIATRICS

Pulmonary hypertension (PH) in pediatrics is a polygenic multifactorial condition with extremely adverse prognosis. Selection of optimal management is a severe task. In absence of treatment the mean life duration in children is not higher one year. Last two decades, revolution in approaches to treatment improved the survival of this patients group. Recently, pediatricians and pediatric cardiologists have three drugs groups that act on the main pathogenetic chains of PH: endothelin pathway, nitric oxide pathway and prostacyclin pathway. At the moment, approaches to pediatric PH are based on the data obtained in the trials on adult patients. However, not long ago there were first randomized trials on children performed. The group of authors of current article presents a modern view on the problem of PH in children, and expert recommendations on children management. Class of recommendations and evidence level were set by the data obtained in pediatric population or on adult population with at least 10% of children included. To the strategy, developed by the Russian clinicians, laid the analysis of experience of the pathology treatment in Russian Federation, as the current practics and clinical guidelines on pediatric PH in Europe, and the recent trials published.

Multicenter mortality and morbidity associated with pulmonary hypertension in the pediatric intensive care unit

Despite advances in the diagnosis and management of pediatric pulmonary hypertension (PH), children with PH represent a growing inpatient population with significant morbidity and mortality. To date, no studies have described the clinical characteristics of children with PH in the pediatric intensive care unit (PICU). A retrospective multicenter cohort study of 153 centers in the Virtual PICU Systems database who submitted data between 1 January 2009 and 31 December 2015 was performed. A total of 14,880/670,098 admissions (2.2%) with a diagnosis of PH were identified. Of these, 2190 (14.7%) had primary PH and 12,690 (85.3%) had secondary PH. Mortality for PH admissions was 6.8% compared to 2.3% in those admitted without PH (odds ratio = 3.1; 95% confidence interval = 2.9–3.4). Compared to patients admitted to the PICU without PH, those with PH were younger, had longer length of stay, higher illness severity scores, were more likely to receive invasive mechanical ventilation, cardiopulmonary resuscitation, extracorporeal membrane oxygenation, and more likely to have co-diagnoses of sepsis, heart failure, and respiratory failure. In a multivariate model, factors significantly associated with mortality for children with PH included age < 6 months or > 16 years, invasive mechanical ventilation, and co-diagnoses of heart failure, sepsis, hemoptysis, disseminated intravascular coagulation, stroke, and multi-organ dysfunction syndrome. Despite therapeutic advances, the disease burden and mortality of children with PH remains significant. Further investigation of the risk factors associated with clinical deterioration and mortality in this population could improve the ability to prognosticate and inform clinical decision-making.

Sildenafil in Infants and Children

Pulmonary arterial hypertension (PAH) management has been transformed in recent times with the advent of cheap and effective diagnostic tools and therapy. Sildenafil, a phosphodiesterase-V inhibitor, has been at the centre of this treatment, and its success in treating PAH has led to its widespread uptake in adult and paediatric pulmonary hypertension (PH), as a first line treatment choice. This might apply to persistent pulmonary hypertension of the newborn (PPHN) or bronchopulmonary dysplasia, as well as to more complex diseases, such as idiopathic pulmonary hypertension. Although recent data regarding long-term mortality and the repeal of Food and Drug Administration (FDA) approval has complicated the issue, Sildenafil continues to be the major treatment option for paediatric PH for patients in a variety of contexts, and this does not seem likely to change in the foreseeable future. In this review, we provide a summary of pulmonary hypertension in infants and children and the use of Sildenafil for such diseases.

Pediatric Development of Bosentan Facilitated by Modeling and Simulation

BACKGROUND

Bosentan is approved for use in adult patients with pulmonary arterial hypertension. The primary aim of the pharmacokinetic modeling was the provision of a systematic guidance for study design and enhanced understanding of pharmacokinetics across the entire pediatric age range.

METHODS

A physiologically based pharmacokinetic model was developed for the pediatric population; starting from an adult model, the effects of body weight, age, and maturation of relevant metabolizing enzymes were incorporated to extrapolate the pharmacokinetics to children. A pediatric population pharmacokinetic model was developed to identify relevant covariates.

RESULTS

Based on model predictions, a dose of 0.5 mg/kg led to an exposure distinguishable from a dose of 2 mg/kg, and an additional blood sampling time point at 2 h (the predicted time of maximum concentration) allowed more precise estimation of bosentan exposure in children. The lower exposure observed in children compared with adults could be explained by maturation-related changes in clearance. Clinical data confirmed the model predictions.

CONCLUSIONS

Maturational changes in drug clearance and developmental changes in body weight were identified as key elements of bosentan pharmacokinetics in pediatric patients. Estimating bosentan exposure using physiologically based and population pharmacokinetic modeling and simulation supported dose selection in pediatric patients. Model-based exposure estimates helped in reducing the number of the youngest pediatric patients to be studied. Pharmacokinetic models can provide a systematic guidance for study design and enhanced understanding of pharmacokinetics across the entire pediatric age range.

[Interstitial processes of the lungs in childhood]

Interstitial processes in the lungs of children can be due to several underlying diseases. Knowledge of the child's age is important as genetic aberrations play a major role in diseases in the first 2 years, whereas immunological diseases are more common starting in kindergarden age. In general lung diseases are rare in children, which makes the diagnostics difficult and results in a delayed diagnosis. In addition, pediatric pulmonologists are often very reluctant to perform lung biopsies due to a lack of a specialized pathologist. In order to make a contribution to the diagnostics of pediatric pulmonary diseases, pathologists should be specialized in pulmonary pathology, have a good knowledge of genetic methods and fetal lung development, which includes the genetic factors involved in lung growth and differentiation. A close cooperation with the pediatric pulmonologist is necessary and each patient should be discussed jointly on an interstitial lung disease board to promote the quality of diagnostics. The pathologist should be aware that the developing lungs of children are not just a smaller form of adult lungs and often react very differently. In this article, we mainly focus on diffuse infiltration patterns, such as ground glass and reticulonodular infiltrations as described in high-resolution computed tomography (HRCT). Localized interstitial processes, which can sometimes be tumor-like and malformations are not dealt with; however, vascular malformations are included as these often manifest as diffuse interstitial infiltrations and must therefore be taken into consideration for the differential diagnostics.

Home Exercise Training in Children and Adolescents with Pulmonary Arterial Hypertension: A Pilot Study

Pulmonary arterial hypertension (PAH) is often associated with impaired exercise capacity. It has been shown that supervised training can improve exercise capacity in adult patients with PAH. The objective of this prospective study was to assess the feasibility of a home exercise training program in children with PAH. Nine children and adolescents (mean age 15.2 ± 3.8 years) with low-risk PAH (defined as mean pulmonary to systemic arterial pressure ratio <0.75; WHO functional class I and II) performed home-based exercise training for 16 weeks. Cardiopulmonary exercise testing and health-related quality of life was evaluated before and after 16 weeks of training. The amount of training at home and patients' well-being was supervised by periodical phone calls and online-questionnaires. Home exercise training was well tolerated in all patients, and no adverse events occurred. After 16 weeks of training, patients significantly improved their exercise capacity [treadmill running distance increased from 589.5 ± 153.9 to 747.9 ± 209.2 m (p = 0.036)]. Oxygen consumption at the anaerobic threshold increased from 1307.8 (±417) to 1406.4 (±418) ml (p = 0.028). Chronotropic index improved from 0.77 ± 0.12 to 0.82 ± 0.11 (p = 0.004) and was slightly related to the increase in running distance (r = 0.62; p = 0.07). Home exercise training is feasible in children and adolescents with low-risk PAH, and the preliminary results of this pilot study indicate beneficial effects. The observed increase in exercise capacity was accompanied by an improved chronotropic competence and increased oxygen consumption at the anaerobic threshold. Future research is needed to investigate the safety and efficacy of home exercise training in a larger population of children with PAH including also patients in WHO functional class III or IV.

Clinical classification in pediatric pulmonary arterial hypertension associated with congenital heart disease

Congenital heart disease (CHD) is a frequent cause of pediatric pulmonary arterial hypertension (PAH), with diverse etiology and outcome. We aimed to describe phenotypic heterogeneity in pediatric PAH associated with CHD (PAH-CHD), assess the applicability of the Nice CHD classification, and explore whether this classification accurately reflects patient/disease characteristics and survival. All children with CHD from a contemporary cohort of consecutive pediatric PAH patients followed in three major referral centers (Denver, New York, the Netherlands) were characterized and classified on the basis of the latest proposed clinical classification for PAH-CHD (World Symposium on Pulmonary Hypertension, Nice, 2013). According to this classification, 24% of 134 children were classified into group 1, 14% into group 2, 19% into group 3, and 30% into group 4; 11% could not be classified. Types of CHD and hemodynamic profile differed between groups, with the highest right atrial pressure in group 4 (P < 0.040). Group 3 children had Down syndrome less frequently (P = 0.011) but other (un)defined syndromes most frequently (P = 0.063) and received most intense PAH-targeted therapy (P = 0.003). With 15 deaths and one lung transplant (12%; median follow-up: 4.3 years), survival differences could not be demonstrated between the groups in the Nice CHD classification. Pediatric PAH-CHD is a heterogeneous condition frequently associated with extracardiac, developmental factors that are believed to affect disease development. The Nice CHD classification identifies groups with specific patient/disease characteristics. However, a substantial proportion of children could not be classified. Group 3 forms a distinct disease entity. Its prognostic value could not be determined because of the low number of events. The Nice CHD classification supports clinical characterization of PAH-CHD; however, further refinement is needed to classify all children with PAH-CHD.

Treatment of children with pulmonary hypertension. Expert consensus statement on the diagnosis and treatment of paediatric pulmonary hypertension. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK

Treatment of children and adults with pulmonary hypertension (PH) with or without cardiac dysfunction has improved in the last two decades. The so-called pulmonary arterial hypertension (PAH)-specific medications currently approved for therapy of adults with PAH target three major pathways (endothelin, nitric oxide, prostacyclin). Moreover, some PH centres may use off-label drugs for compassionate use. Pulmonary hypertensive vascular disease (PHVD) in children is complex, and selection of appropriate therapies remains difficult. In addition, paediatric PAH/PHVD therapy is vastly based on experience and trial data from adult rather than paediatric studies; however, the first randomised paediatric PAH trials have been conducted recently. We present consensus recommendations for the treatment of children with PH. Class of recommendation and level of evidence were assigned based on paediatric data only or on adult studies that included >10% children. After a systematic literature search and analysis of the published data, we developed treatment strategies and algorithms that can guide goal-oriented PH therapy. We discuss early combination therapy (double, triple) in patients with PAH in functional class II-IV and in those with inadequate response to the initial pharmacotherapy. In those children with progressive, severe PAH and inadequate response, advances in drug development, and interventional and surgical approaches provide promising new strategies to avoid, reverse or ameliorate right heart failure and left ventricular compression. In particular, first follow-up data indicate that Potts shunt (left pulmonary artery to descending aorta anastomosis) may be an alternative destination therapy, or bridge to bilateral lung transplantation, in end-stage paediatric PAH.

Stability of an Extemporaneously Compounded Oral Suspension of Bosentan

PURPOSE

To assess the stability of an extemporaneously compounded oral suspension of bosentan from commercially available tablets for a period of 1 month.

METHODS

A 6.25 mg/mL oral suspension of bosentan monohydrate was prepared from Tracleer tablets. The bosentan suspension was then evenly divided between 2 light-resistant prescription bottles and stored in the dark either under refrigeration (4-8°C) or at controlled room temperature (21-26°C). The suspensions were assessed for physical changes (ease of resuspendability, change in color, change in odor), and samples were drawn immediately after preparation and on days 0, 1, 3, 7, 10, 14, 21, 28, and 31. Samples were analyzed at each time point by high-performance liquid chromatography (HPLC) utilizing a reversed-phase column with chemical stability defined as the retention of at least 90% of the initial intact bosentan concentration measured.

RESULTS

No change in suspendability, color, or odor of the compounded bosentan suspensions was noted throughout the storage period. Furthermore, regardless of storage conditions, the oral suspension of bosentan retained at least 94% of the active pharmaceutical ingredient for 31 days after preparation.

CONCLUSION

The results of our study indicate that a 6.25 mg/mL bosentan oral suspension stored in the dark under refrigeration and at room temperature maintains physical and chemical stability for 1 month.

Clinical and prognostic value of endothelin-1 and big endothelin-1 expression in children with pulmonary hypertension

OBJECTIVE

Pulmonary arterial hypertension is known to be associated with increased expression of endothelin (ET)-1 and its precursor big ET-1. Therefore, we hypothesised that in children with pulmonary hypertension (PH) altered levels of ET-1 and big ET-1 may have clinical and prognostic impact.

METHODS

Sixty-six children with different forms of PH (mean age 10.4±9.7 years) were included. Blood samples were taken from the pulmonary artery and a systemic artery. Levels of ET-1/big ET-1 were measured via ELISA method and compared with clinical and haemodynamic data. To assess prognostic relevance, Kaplan-Meier survival analysis was conducted with definition of end point as the composite of mortality, lung transplantation, use of intravenous prostanoids and Potts shunt creation.

RESULTS

ET-1 levels ranged between 0.09 and 11.64 (mean 1.48±2.34) fmol/mL, and big ET-1 levels between 0.05 and 2.92 (mean 0.84±0.58) fmol/mL. No significant relationships were found between ET-1/big ET-1 levels and functional class as well as haemodynamic indices of PH severity. Mean follow-up after catheterisation was 63.2±44.1 months. While 31 of the 66 (47%) patients with PH reached a predefined end point, there was no significant relation between levels of ET-1/big ET-1 and patient outcome.

CONCLUSIONS

Although children with PH had alterations in ET-1/big ET-1 expression, which may reflect changes in net release or lung clearance, levels of ET-1/big ET-1 showed no correlation with clinical and haemodynamic parameters, and were not able to predict outcome.

Persistent Challenges in Pediatric Pulmonary Hypertension

Pulmonary hypertension and related pulmonary vascular diseases cause significant morbidities and high mortality and present many unique challenges toward improving outcomes in neonates, infants, and children. Differences between pediatric and adult disease are reflected in controversies regarding etiologies, classification, epidemiology, diagnostic evaluations, and therapeutic interventions. This brief review highlights several key topics reflecting recent advances in the field and identifies persistent gaps in our understanding of clinical pediatric pulmonary hypertension.

Change in Pediatric Functional Classification During Treatment and Morbidity and Mortality in Children with Pulmonary Hypertension

Despite advances in therapy, outcomes for children with pulmonary hypertension remain poor. We sought to assess the validity of a pediatric-specific functional classification system for pulmonary hypertension (PH) in a heterogeneous population of children with PH diagnosed by echocardiogram or cardiac catheterization. A single-center, retrospective study of 65 infants and children with PH was performed. Pediatric Functional Class (FC) at diagnosis, at last visit, and change in FC over time were evaluated for their association with mortality and PH-associated morbidity in univariate, time-to-event, and multivariate regression analyses. Median age at PH diagnosis was 5.3 months (0 days-12.7 years). Twenty-five children (38 %) had idiopathic PH or PH secondary to congenital heart disease, one (2 %) had left heart disease, and 39 (60 %) had PH secondary to respiratory disease. Mortality was 25 % (16/63), primarily in the first year of follow-up. FC at diagnosis was not significantly associated with survival (p = 0.22), but higher FC (more impaired) at last visit (p < 0.001) and change in FC over time (HR 2.3, 95 % confidence interval 1.3-4, p = 0.0003) were associated with mortality. Higher FC at last visit was associated with greater days of hospitalization in the intensive care unit per year (p = 0.006) and history of cardiac arrest (p = 0.012) and syncope (p = 0.02). Although pediatric FC at diagnosis was not predictive of mortality, response to therapy (as assessed by change in FC over time and FC at last visit) was associated with morbidity and mortality in this heterogeneous cohort. Multicenter prospective studies are necessary to further validate these findings.

Current Concepts in Management of Pulmonary Hypertension: Fighting the Old Demon with Modern Weapons

Pulmonary hypertension in children is a rare disease associated with high morbidity and mortality. The pathogenesis is not fully understood. Diagnostic evaluation focuses on ruling out other etiologies of pulmonary hypertension and prognosticating the disease. Congenital heart disease and left sided heart disease associated pulmonary hypertension are more common in children. Therapies for idiopathic pulmonary hypertension have evolved over the past decade. Phosphodiesterase 5 inhibitors (sildenafil, tadalafil), endothelin antagonists (Bosentan and ambrisentan) and prostanoids are the classes of drugs shown to be useful in pulmonary hypertension. However, use of these drugs in children is based on extrapolation of adult usage and on expert consensus rather than based on randomized controlled trial evidence. Despite these advances, the outcomes of various forms of pulmonary hypertension remain poor, especially in India, where some forms of therapy are not available and children often are diagnosed at an advanced stage of disease.

The limits of oral therapy in pulmonary arterial hypertension management

Pulmonary arterial hypertension (PAH) is a devastating disease in which remodeling of the small pulmonary arteries leads to a progressive increase in pulmonary vascular resistance and right-sided heart failure. Over the past decade, new treatments for PAH, such as the use of ERAs, PDE-5 inhibitors and prostacyclin analogs, have brought about dramatic improvements in clinical outcomes. Epoprostenol infusion therapy has been shown to improve hemodynamics, functional status, and survival, and it remains the gold standard for treatment of patients with severe PAH. Many agents, approved for PAH are always delivered in pill form. Although oral therapy occupies an important position, it has some drawbacks and limitations in PAH management. For patients in World Health Organization functional class IV and with severe right heart failure, there are few data on the long-term survival of patients treated with oral medications. Further research, exploration, and clinical experience with oral therapy in severe PAH and combination therapy will redefine its position in PAH management.

Pediatric Pulmonary Hypertension: Guidelines From the American Heart Association and American Thoracic Society

Pulmonary hypertension is associated with diverse cardiac, pulmonary, and systemic diseases in neonates, infants, and older children and contributes to significant morbidity and mortality. However, current approaches to caring for pediatric patients with pulmonary hypertension 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 panel of experienced clinicians and clinician-scientists was assembled to review the current literature and to make recommendations on the diagnosis, evaluation, and treatment of pediatric pulmonary hypertension. This publication presents the results of extensive literature reviews, discussions, and formal scoring of recommendations for the care of children with pulmonary hypertension.

Haemodynamic characterisation and heart catheterisation complications in children with pulmonary hypertension: Insights from the Global TOPP Registry (tracking outcomes and practice in paediatric pulmonary hypertension)

BACKGROUND

The TOPP Registry has been designed to provide epidemiologic, diagnostic, clinical, and outcome data on children with pulmonary hypertension (PH) confirmed by heart catheterisation (HC). This study aims to identify important characteristics of the haemodynamic profile at diagnosis and HC complications of paediatric patients presenting with PH.

METHODS AND RESULTS

HC data sets underwent a blinded review for confirmation of PH (defined as mean pulmonary arterial pressure ≥ 25 mmHg, pulmonary capillary wedge pressure ≤ 12 mmHg and pulmonary vascular resistance index [PVRI] of >3 WU × m(2)). Of 568 patients enrolled, 472 who fulfilled the inclusion criteria and had sufficient data from HC were analysed. A total of 908 diagnostic and follow-up HCs were performed and complications occurred in 5.9% of all HCs including five (0.6%) deaths. General anaesthesia (GA) was used in 53%, and conscious sedation in 47%. Complications at diagnosis were more likely to occur if GA was used (p=0.04) and with higher functional class (p=0.02). Mean cardiac index (CI) was within normal limits at diagnosis when analysed for the entire group (3.7 L/min/m(2); 95% confidence interval 3.4-4.1), as was right atrial pressure despite a severely increased PVRI (16.6 WU × m(2,) 95% confidence interval 15.6-17.76). However, 24% of the patients had a CI of <2.5L/min/m(2) at diagnosis. A progressive increase in PVRI and decrease in CI was observed with age (p<0.001).

CONCLUSION

In TOPP, haemodynamic assessment was remarkable for preserved CI in the majority of patients despite severely elevated PVRI. HC-related complication incidence was 5.9%, and was associated with GA and higher functional class.

FUTURE-2: Results from an open-label, long-term safety and tolerability extension study using the pediatric FormUlation of bosenTan in pUlmonary arterial hypeRtEnsion

BACKGROUND

A novel formulation of bosentan was evaluated in children with pulmonary arterial hypertension (PAH) in FUTURE-1, which characterized its pharmacokinetic and clinical profile. The subsequent phase III, open-label, long-term extension study, FUTURE-2, aimed to provide long-term tolerability, safety and exploratory efficacy data.

METHODS

Children (≥2 and <12 years) with idiopathic or heritable PAH, who completed 12-week treatment in FUTURE-1 and for whom bosentan was considered beneficial were enrolled, and continued to receive bosentan 4 mg/kg twice-daily, which could be down-titrated to 2mg/kg if not tolerated. Safety and tolerability were evaluated via treatment-emergent adverse events (AEs), serious AEs, growth, and laboratory measurements. Exploratory efficacy endpoints included time to PAH worsening and long-term survival. All analyses were conducted on pooled data of both studies.

RESULTS

36 patients were enrolled in FUTURE-1 and 33 continued in FUTURE-2. The overall median duration of exposure to bosentan was 27.7 (range 1.9-59.6) months. Treatment-emergent AEs occurred in 32 (88.9%) patients; AEs considered treatment-related in 15 (41.7%) patients. Of 51 serious AEs, three were considered treatment-related: two incidences of reported PAH worsening and one of autoimmune hepatitis. Six deaths occurred; none were considered treatment-related. Kaplan-Meier event-free estimates of PAH worsening were 78.9% and 73.6% at 2 and 4 years, respectively.

CONCLUSIONS

The pediatric bosentan formulation was generally well tolerated, its safety profile comparable to that of the adult formulation when used in children. The results are in line with the efficacy profile of bosentan in previous pediatric and adult PAH studies of shorter duration.

Treating pulmonary hypertension in pediatrics

INTRODUCTION

Pulmonary hypertension is a hemodynamic condition occurring rarely in pediatrics. Nevertheless, it is associated with significant morbidity and mortality. When characterized by progressive pulmonary vascular structural changes, the disease is called pulmonary arterial hypertension (PAH). It results in increased pulmonary vascular resistance and eventual right ventricular failure. In the vast majority of cases, pediatric PAH is idiopathic or associated with congenital heart disease, and, contrary to adult PAH, is rarely associated with connective tissue, portal hypertension, HIV infection or thromboembolic disease.

AREAS COVERED

This article reviews the current drug therapies available for the management of pediatric PAH. These treatments target the recognized pathophysiological pathways of PAH with endothelin-1 receptor antagonists, prostacyclin analogs and PDE type 5 inhibitors. New treatments and explored pathways are briefly discussed.

EXPERT OPINION

Although there is still no cure for PAH, quality of life and survival have been improved significantly with specific drug therapies. Nevertheless, management of pediatric PAH remains challenging, and depends mainly on results from adult clinical trials and pediatric experts. Further research on PAH-specific treatments in the pediatric population and data from international registries are needed to identify optimal therapeutic strategies and treatment goals in the pediatric population.

Echocardiography in Pediatric Pulmonary Arterial Hypertension

Background—

The value of echocardiography in assessing disease severity and predicting outcome in pediatric pulmonary arterial hypertension (PAH) is insufficiently defined. The aim of this study was to describe correlations between echocardiography and disease severity and outcome in pediatric PAH.

Methods and Results—

Forty-three consecutive children (median age, 8.0 years; range, 0.4–21.5) with idiopathic/hereditary PAH (n=25) or PAH associated with congenital heart disease (n=18) were enrolled in a prospective single-center observational study. Anatomic and right ventricular-functional variables were obtained by two-dimensional echocardiography and Doppler-echocardiography at presentation and at standardized follow-up and were correlated with measures of disease severity (World Health Organization functional class [WHO-FC], N-terminal-pro-B-type natriuretic peptide, hemodynamics) and lung-transplantation–free survival. Right atrial and right ventricular dimensions correlated with WHO-FC and hemodynamics ( P <0.05), whereas left ventricular dimensions correlated with hemodynamics and survival ( P <0.05). Right-to-left ventricular dimension ratiocorrelated with WHO-FC, hemodynamics and survival ( P <0.05). Right ventricular ejection time correlated with hemodynamics and survival ( P <0.05) and tended to correlate with WHO-FC ( P =0.071). Tricuspid annular plane systolic excursion correlated with WHO-FC, mean right atrial pressure and survival ( P <0.05).

Conclusions—

This early descriptive study shows that echocardiographic chararacteristics of both the right and the left heart correlate with disease severity and outcome in pediatric PAH, both at presentation and during the course of the disease. The preliminary data from this study support the potential value of echocardiography as a tool in guiding management in children with PAH.