Pulmonary arterial hypertension in children

Pulmonary Hypertension in Children

Pulmonary hypertension (PH) may manifest at any age, including during childhood. While pediatric PH frequently associates with early life alterations that cause occult or overt pulmonary vascular disease, all forms of PH seen in adults are also found in children, although with different degrees of prevalence according to PH subtype. PH-specific medications, rapid implementation of therapeutic advances, multidisciplinary teams for improved child and family support, and programs to facilitate successful transition to adult care have contributed to substantial improvement in survival to adulthood.

Impact of obstructive sleep apnea in cardiovascular risk in the pediatric population: A systematic review

While the association of obstructive sleep apnea (OSA) with an increased cardiovascular risk (CVR) in the adult population is well known, there is insufficient evidence to affirm something similar in the pediatric population. On the other hand, adenotonsillectomy has been shown to be an effective treatment. Our objective was to evaluate the association of sleep respiratory disorders in children with increased CVR and the impact of adenotonsillectomy in the literature. To this aim, a literature search was conducted, between 2002 to the present. After carrying out a systematic review, the following results were provided: thoracic echocardiography after surgery found improvements in terms of cardiac function and structure; blood pressure (BP) measurement, verified a tendency to higher BP values in the OSA pediatric population, which improved after surgery; different biomarkers of CVR, were increased in OSA patients and improved after treatment and finally; some studies found endothelial dysfunction in pediatric OSA, a measurement of vascular system function, was reversible with adenotonsillectomy. Increases in BP parameters, biological markers related to CVR and alterations in cardiac function structure, have been reported in pediatric patients with OSA. At least, some of these parameters would be reversible after adenotonsillectomy, reflecting a possible reduction in CVR.

Genetics dictating therapeutic decisions in pediatric pulmonary hypertension? A case report suggesting we are getting closer

Despite therapeutic advances over the past decades, pulmonary arterial hypertension (PAH) and related pulmonary vascular diseases continue to cause significant morbidity and mortality in neonates, infants, and children. Unfortunately, an adequate understanding of underlying biology is lacking. There has been a growing interest in the role that genetic factors influence pulmonary vascular disease, with the hope that genetic information may aid in identifying disease etiologies, guide therapeutic decisions, and ultimately identify novel therapeutic targets. In fact, current data suggest that genetic factors contribute to ~42% of pediatric‐onset PH compared to ~12.5% of adult‐onset PAH. We report a case in which the knowledge that biallelic ATP13A3 mutations are associated with malignant progression of PAH in young childhood, led us to alter our traditional treatment plan for a 21‐month‐old PAH patient. In this case, we elected to perform a historically high‐risk Potts shunt before expected rapid deterioration. Short‐term follow‐up is encouraging, and the patient remains the only known surviving pediatric PAH patient with an associated biallelic ATP13A3 mutation in the literature. We speculate that an increased use of comprehensive genetic testing can aid in identifying the underlying pathobiology and the expected natural history, and guide treatment plans among PAH patients.

Assessment of preoperative and postoperative cardiac function in children with adenotonsillar hypertrophy: a prospective cohort study

PURPOSE

Chronic upper airway obstruction caused by adenotonsillar hypertrophy is one of the major cause of morbidity in children. It can lead to Obstructive Sleep Apnoea Syndrome, Pulmonary Hypertension, Cor Pulmonale and right heart failure. The study aimed to evaluate and compare various parameters of cardiac function with the help of echocardiography preoperatively and postoperatively in children undergoing adenotonsillectomy.

METHODOLOGY

A prospective cohort study was conducted on 23 patients at an apex care institute, under the age group of 4-12 years, who were diagnosed with adenotonsillar hypertrophy. Preoperative symptom analysis and Echocardiographic examination were done. After the assessment, all patients underwent surgery in the form of adenotonsillectomy. Follow-up symptom analysis and echocardiographic examination was done after 3 months postoperatively.

RESULTS

Significant improvement in the obstructive symptoms were noted in postoperative group as expected (p =  < 0.001) and also in parameters such as mPAP (p =  < 0.001), TAPSE (p =  < 0.001), TAV (p = 0.001), Ejection fraction (p = 0.027) and RVMPI (p = 0.044) were improved in postoperative group. 4 patients had Grade 1 Right ventricular diastolic dysfunction, which disappeared in three patients postoperatively.

CONCLUSION

We have concluded that there can be subclinical cardiac dysfunctions which occurs as a result of chronic upper airway obstruction due to untreated adenotonsillar hypertrophy. Routine cardiac screening in children presenting with sleep disordered breathing associated with adenotonsillar hypertrophy may be helpful in identifying and preventing the development of cardiopulmonary complication. These changes can be reversed by performing adenotonsillectomy.

Characterisation of Pediatric Pulmonary Hypertensive Vascular Disease from the PPHNet Registry

BACKGROUND

There are limited data about the range of diseases, natural history, age-appropriate endpoints and optimal care for children with pulmonary hypertension (PH), including the need for developing high quality patient registries of children with diverse forms of PH to enhance care and research.

OBJECTIVE

To characterise the distribution and clinical features of diseases associated with pediatric PH, including natural history, evaluation, therapeutic interventions and outcomes, as defined by the WSPH Classification.

METHODS

1475 patients were enrolled into a multisite registry across the Pediatric Pulmonary Hypertension Network (PPHNet), comprised of 8 interdisciplinary PH programs.

RESULTS

WSPH Groups 1 (PAH) and 3 (lung disease) were the most common primary classifications (45% and 49% of subjects, respectively). The most common Group 3 conditions were BPD and CDH. Group 1 disease was predominantly associated with congenital heart disease (60%) and idiopathic (23% of Group 1 cases). In comparison with Group 1, Group 3 subjects had better disease resolution (HR=3.1, p<0.001), tended to be younger at diagnosis (0.3 (0.0,0.6) versus 1.6 (0.1,6.9) years (median (IQR); p<0.001), and were more often male (57% versus. 45%, p<0.001). Down syndrome (DS), the most common genetic syndrome in the registry, constituted 11% of the entire PH cohort.

CONCLUSIONS

We find a striking proportion of pediatric PH patients with Group 3 disorders, reflecting the growing recognition of PH in diverse developmental lung diseases. Greater precision of clinical phenotyping based on disease-specific characterization may further enhance care and research of pediatric PH.

Pulmonary arterial pressure in at-term in vitro fertilization neonates: A cross-sectional study

Objective:

Hormones consumption in women who conceive through in vitro fertilization (IVF) as well as embryonic manipulations have raised concerns regarding the neonates’ health, including the possibility of pulmonary hypertension. This study, therefore, aimed to assess the pulmonary arterial pressure in at-term IVF neonates.

Materials and Methods:

This prospective cross-sectional study was conducted between March 2013 and October 2017 and compares 160 IVF neonates (group 1) with 160 naturally conceived neonates (group 2). The neonates in both groups were cesarean newborns, matched in terms of gestational and neonatal age. The neonates were three-seven days old, had a full-term gestational age of 37-39 weeks and 6 days, and a normal birth weight of 2500-4000 gr. The systolic pulmonary artery pressure (SPAP) was estimated using real-time echocardiography on the basis of peak flow velocity of tricuspid regurgitation jet.

Results:

A significant difference was observed in the mean SPAPs between the two groups (p<0.001). Although, the effect of gestational age on reducing SPAP was greater and statistically significant in group 1, the gradual decrease in the PAP after birth appeared to be slower in this group. Moreover, in both groups, the effect of gestational age on reducing SPAP was more convincing than that of the neonatal age. Further, in both groups, a significant reverse correlation was observed between the SPAP and the neonatal weight; however, it appeared to be markedly higher in group 1.

Conclusion:

Our study renders IVF as being culpable in the incidence of pulmonary hypertension among neonates. Hence, to detect the likelihood of pulmonary arterial hypertension in IVF neonates, it is recommended to monitor their PAP during the neonatal period, and thereby facilitate them with the required treatment.

Use of Treprostinil in Pediatric Pulmonary Hypertension: Case Reports and Review of the Literature

BACKGROUND

Add-on therapy with prostacyclin in pediatric refractory pulmonary hypertension (PH) poses a challenge, especially when considering continuous intravenous administration in younger children. A search for alternate routes of drug delivery has led to the clinical investigation of stable and long-acting prostacyclin analogues, such as subcutaneous treprostinil. We reported 2 pediatric cases of PH treated with subcutaneous treprostinil and reviewed the literature on treprostinil use in children.

METHOD

The literature review used 3 electronic databases and a combination of terms (treprostinil, pediatric, PH, prostanoid, etc). We also searched for pediatric clinical trials on treprostinil registered on international clinical trial registries.

RESULTS

The reported cases highlighted the multifactorial nature of PH in pediatrics: a female child with a giant omphalocele, and intracardiac and extracardiac shunts; and a male premature child with a congenital diaphragmatic hernia and long-term PH. The literature review identified 19 studies reporting treprostinil use in 421 children with various types of PH (groups 1 and 3). Subcutaneous treprostinil was the most administered formulation, at a mean dose of 40 ng/kg/min. Overall, 12 clinical trials on treprostinil for children with PH were registered on the clinical trial registries. Most authors concluded that subcutaneous treprostinil was effective, well tolerated, and represented an alternative to intravenous epoprostenol.

CONCLUSIONS

Subcutaneous treprostinil may be a useful adjunct in the therapeutic algorithm for children with severe PH, refractory to oral drugs, and after a complete check-up for all PH etiologies.

Management of Pulmonary Arterial Hypertension in the Pediatric Patient

PURPOSE OF REVIEW

Pediatric pulmonary arterial hypertension (PAH) is associated with significant morbidity and mortality. Herein we review the diagnosis and classification for pediatric PAH and detail the current therapeutic options available for use in the pediatric PAH population.

RECENT FINDINGS

Classification and treatment of pediatric PAH is guided by adult criteria and treatment algorithms, yet the distribution of factors contributing to PAH in children differs significantly from that seen in adults. It is necessary to understand these differences in order to appropriately tailor therapy to the needs of the child or adolescent. An expanding array of targeted PAH drugs are now approved for use in adults, and many of these drugs are used "off-label" to treat children and adolescents with PAH. Use of these novel therapies has coincided with marked improvement in outcomes, suggesting significant benefit. However, because most of these drugs have not been studied in rigorous randomized, controlled trials in children, it is critical that physicians understand their mechanisms of action, potential benefits, and safety profiles. Pediatric PAH outcomes have improved substantially in the modern era, coinciding with the "off-label" use of targeted PAH drugs in children and adolescents. Ideally, care should be provided at centers with specialized expertise in the diagnosis and treatment of pediatric PAH by providers who understand the appropriate diagnostic algorithms, classification schemes, and treatment approaches.

Characteristics of Patent Ductus Arteriosus in Congenital Rubella Syndrome

This study investigated the characteristics of congenital rubella syndrome (CRS)-associated cardiac complications, particularly patent ductus arteriosus (PDA). We reviewed the medical records of patients with CRS who were admitted to the Children's Hospital 1 in Vietnam between December 2010 and December 2012, and patients with CRS who underwent PDA transcatheter occlusion therapy at the cardiology department between December 2009 and December 2015. We compared the characteristics of PDA treated with transcatheter closure between children with CRS (CRS-PDA) and those without CRS (non-CRS-PDA) who underwent PDA transcatheter closure between July 2014 and December 2015. One-hundred-and-eight children with CRS were enrolled. Cardiac defects (99%), cataracts (72%), and hearing impairment (7%) were detected. Fifty CRS-PDA and 290 non-CRS-PDA patients were examined. CRS-PDA patients had smaller median birthweight (p < 0.001), more frequent pulmonary (p < 0.001) and aortic stenosis (p < 0.001), higher main pulmonary artery pressure, and higher aortic pressure in systole/diastole (p < 0.001 for each) than did non-CRS-PDA patients. The proportion of tubular-type PDA was higher in CRS-PDA patients (16%) than in non-CRS-PDA patients (3%) (p = 0.020). Tubular-type PDA was frequently seen in patients with CRS and accompanied by pulmonary/systemic hypertension and pulmonary/aortic stenosis; in these patients, more cautious device selection is needed for transcatheter PDA closure.

Platelet activation markers in children with congenital heart disease associated with pulmonary arterial hypertension

BACKGROUND

Mean platelet volume (MPV), platecrit, and platelet distribution width (PDW) are markers of platelet activation. Previous studies have found that platelet activation occurs in patients with pulmonary arterial hypertension. Platelet indices including MPV, PDW, and platecrit have not been studied in children with congenital heart disease associated pulmonary arterial hypertension (APAH-CHD) who survived and those who died.

OBJECTIVE

The objective of this study to investigate the value of platelet indices with clinical and hemodynamic indicators predicting the disease severity and survival in children with APAH-CHD.

METHODS

This was a nested case-control study. MPV, platecrit, and PDW levels measured in 37 patients with APAH-CHD and 43 healthy subjects at the beginning of the study. Right heart catheterization was performed in all 37 patients. Clinical and hemodynamic data were collected. All patients were followed from the date of laboratory testing. The study was conducted between March 2012-July 2015. The comparison of clinical, hemodynamic data and platelet indices were made between patients with APAH-CHD who died than APAH-CHD patients who survived.

RESULTS

Of 37 patients, after a mean follow-up duration of 67.90 ± 47.90 months, 11 patients died. MPV (12.10 femoliter [fL; 8.20-12.50] vs 8.70 fL [6.40-9.70], P = .007), PDW (16.88 ± 1.09% vs 15.75 ± 1.58%, P = .04) and platecrit (0.28 ± 0.31 vs 0.22 ± 0.27, P = .01) were significantly higher in the patients with APAH-CHD who died than those who survived. Pearson's correlation analysis showed that MPV correlated with mean pulmonary artery pressure (r = 0.332, P = .04) and correlated negatively with six-minute walking distance (r = -0.600. P = .00). PDW and platecrit correlated positively with mean pulmonary artery pressure (r = 0.373, P = .02; r = 0.389, P = .01, respectively).

CONCLUSION

Our results showed that MPV, platecrit and PDW were increased in children with APAH-CHD. They might give clue about disease severity.

The burden of rheumatic heart disease among children in Lagos: how are we fairing?

INTRODUCTION

Rheumatic heart disease still remains a cause of morbidity and mortality in low and middle income countries, despite its eradication in developed societies. The study aimed to document the features of children with rheumatic heart disease using clinical evaluation and echocardiography and compare it with reports from other part of the country.

METHODS

A review of a prospectively collected data of patients with rheumatic heart disease who had echocardiography done from April 2007-Dec 2016. Information obtained from patients include age, sex, clinical indication for echocardiography, echocardiographic characterization of the valvular lesions and associated complications.

RESULTS

A total of 324,676 patients were seen at the Paediatric unit of LASUTH from 2007 to 2016, out of which 36 had Rheumatic heart disease. This translates to a prevalence of 1.1 per 10,000 patients who presented at the study site during the study period. The prevalence of RHD amongst all the patients with structural heart disease was 2.6%. The mean age of patients was 9.12 ± 2.75 years with a male to female ratio of 1.6: 1. The most common valve affected was mitral valve. Heart failure was the most common mode of presentation found in 91.6%. Other complications were pulmonary hypertension and pericardial effusion.

CONCLUSION

Rheumatic heart disease is still prevalent among children in Lagos although the prevalence is reducing. Heartfailure is the commonest mode of presentation and complication in them.

A Retrospective Review of Infants Receiving Sildenafil

OBJECTIVE

The purpose of the study was to assess mortality in an infant population receiving sildenafil.

METHODS

A retrospective review of hospitalized infants at Children's Hospital Los Angeles who received sildenafil between 2008 and 2012 was conducted. Patient characteristics, comorbidities, and treatment characteristics were analyzed. Primary outcome was mortality at discharge. Sildenafil dosage ranges were based on the Sildenafil in Treatment-Naïve Children, Aged 1-17 Years, With Pulmonary Arterial Hypertension trial and were categorized as small (<1.5 mg/kg/day), medium (1.5-3.75 mg/kg/day), large (3.76-7.5 mg/kg/day), and very large (>7.5 mg/kg/day).

RESULTS

A total of 147 infants were studied. A total of 82% of patients had severe pulmonary hypertension. Our data revealed 29% mortality at discharge. Mortality increased with increasing sildenafil dosage: 14% (small), 19% (medium), 49% (large), and 90% (very large). On multivariate analysis of sildenafil dosage, other pulmonary hypertension therapies, presence of persistent cardiac shunts, and duration of sildenafil, odds of dying were significantly higher with combined high and very high sildenafil dosage groups compared with combined low and medium dosage groups (OR, 13.2; CI, 4.4-39.5; p < 0.0001).

CONCLUSION

Sildenafil was given to critically ill infants with multiple risk factors for mortality. Although higher doses cannot be causally related to mortality, there appears to be no added benefit by escalating the sildenafil dose.

Challenges in the development of chronic pulmonary hypertension models in large animals

Pulmonary hypertension (PH) results in significant morbidity and mortality. Chronic PH animal models may advance the study of PH's mechanisms, evolution, and therapy. In this report, we describe the challenges and successes in developing three models of chronic PH in large animals: two models (one canine and one swine) utilized repeated infusions of ceramic microspheres into the pulmonary vascular bed, and the third model employed a surgical aorto-pulmonary shunt. In the canine model, seven dogs underwent microsphere infusions that resulted in progressive elevation of pulmonary arterial pressure over a few months. In this model, pulmonary endoarterial tissue was obtained for histology. In the aorto-pulmonary shunt swine model, 17 pigs developed systemic level pulmonary pressures after 2-3 months. In this model, pulmonary endoarterial tissue was sequentially obtained to assess for changes in gene and microRNA expression. In the swine microsphere infusion model, three pigs developed only a modest chronic increase in pulmonary arterial pressure, despite repeated infusions of microspheres (up to 40 in one animal). The main purpose of this model was for vasodilator testing, which was performed successfully immediately after acute microsphere infusions. Chronic PH in large animal models can be successfully created; however, a model's characteristics need to match the investigational goals.

Speckle-Tracking Echocardiographic Measures of Right Ventricular Diastolic Function Correlate with Reference Standard Measures Before and After Preload Alteration in Children

The accuracy of echocardiographic measures of right ventricular (RV) diastolic function has been sparsely studied. Our objective was to evaluate the correlation between echocardiographic and reference standard measures of RV diastolic function derived from micromanometer pressure analysis before and after preload alteration in children. Echocardiograms and micromanometer pressure analyses were prospectively performed before and after fluid bolus in children undergoing right heart catheterization. The isovolumic relaxation time constant (τ) and end-diastolic pressure (EDP) were measured. Conventional and speckle-tracking echocardiographic (STE) parameters of RV systolic and diastolic function were assessed. Normal saline bolus was given to increase RV EDP by 20 %. Twenty-eight studies were performed in 22 patients with congenital heart disease or postheart transplantation. Mean age was 8.7 ± 6.1 years. RV longitudinal early diastolic strain rate (EDSR) correlated with τ before (r = 0.57, p = 0.001) and after fluid bolus (r = 0.48, p = 0.008). No conventional echocardiographic measures correlated with τ both before and after fluid bolus. Multiple regression analysis revealed RV EDSR and LV circumferential EDSR as independent predictors of RV τ. There were no independent predictors of EDP. RV EDSR appears to correlate with the reference standard measure of early active ventricular relaxation in children at baseline and after changes in preload. Conventional echocardiographic measures of diastolic function were not predictive of diastolic function after preload alteration. Future studies should assess the prognostic significance of STE measures of diastolic function in this population.

Pulmonary Arterial Capacitance Index Is a Strong Predictor for Adverse Outcome in Children with Idiopathic and Heritable Pulmonary Arterial Hypertension

OBJECTIVES

To evaluate the clinical utility of pulmonary artery capacitance index (PACi) in the assessment of disease severity and prognostic value in children with idiopathic and heritable pulmonary arterial hypertension (PAH).

STUDY DESIGN

PACi is defined as the ratio of stroke volume index over pulmonary pulse pressure. A retrospective study was performed to compare PACi, brain natriuretic peptide (BNP), 6-minute walk distance, New York Heart association (NYHA) functional class, and adverse outcomes (hospitalization due to heart failure, lung transplantation, and cardiac mortality) in 72 Japanese children (10 ± 3.6 years) with idiopathic and heritable PAH.

RESULTS

PACi had significant correlations with pulmonary vascular resistance index (r =-0.73, P < .0001), BNP levels (r = -0.40, P = .0008), and 6-minute walk distance (r = 0.57, P < .05). Statistically significant differences in PACi were observed between NYHA functional class II vs combined III and IV (median; 1.1 vs 0.6 mL/mm Hg/m², respectively, P < .05). There were 25 of 72 (35%) children who had an adverse event including initiation of hospitalization due to heart failure, lung transplantation, and death. Cumulative event-free survival rate was significantly lower when PACi was <0.85 mL/mm Hg/m² (log-rank test, P < .0001).

CONCLUSIONS

PACi correlated with BNP and NYHA functional class and may serve as a strong prognostic marker in children with idiopathic and heritable PAH.

Noninvasive assessment of pulmonary arterial capacitance by pulmonary annular motion velocity in children with ventricular septal defect

Background

We hypothesized that longitudinal pulmonary arterial deformation during the cardiac cycle reflects pulmonary arterial capacitance. To examine this hypothesis, we assessed whether tissue Doppler-derived pulmonary annular motion could serve as a novel way to evaluate pulmonary arterial capacitance in pediatric patients with ventricular septal defect (VSD).

Methods

In this prospective study, pulmonary annular velocity was measured in children (age, 6 months–5 years) with a preoperative VSD (VSD group, n = 35) and age-matched healthy children (Control group, n = 23). Pulmonary artery capacitance was calculated by two methods. Systolic pulmonary arterial capacitance (sPAC) was expressed as the stroke volume/pulmonary arterial pulse pressure. Diastolic pulmonary arterial capacitance (dPAC) was determined according to a two-element windkessel model of the pulmonary arterial diastolic pressure profile.

Results

Pulmonary annular velocity waveforms comprised systolic bimodal (s1′ and s2′) and diastolic e’ and a’ waves in all participants. The peak velocities of s1′, s2′, and e’ were significantly lower in the VSD group than in the Control group. On multiple regression analysis, sPAC was an independent variable affecting the peak velocities of the s1′, s2′, and e’ waves (β = 0.41, 0.62, and 0.35, respectively). The dPAC affected the s1′ wave peak velocity (β = 0.34). The time durations of the s1′ and e’ waves were independently determined by the sPAC (β = 0.49 and 0.27).

Conclusion

Pulmonary annular motion velocity evaluated using tissue Doppler is a promising method of assessing pulmonary arterial capacitance in children with VSD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12947-016-0081-4) contains supplementary material, which is available to authorized users.

Epigenetic regulation of insulin-like growth factor signaling: A novel insight into the pathophysiology of neonatal pulmonary hypertension

Burdened by high morbidity and mortality, neonatal pulmonary hypertension (PH) is a life-threatening pathophysiological condition that progressively elevates the mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR). Pulmonary vascular remodeling and vasoconstriction are recognized pathophysiological features of the disease. Neonatal PH is a serious pathological condition in which persistent PH of the newborn causes hypoxemia and right-to-left extrapulmonary shunting of blood flow, leading to right heart failure and serious life-threatening complications. Recently, the role of growth factors in the pathogenesis of neonatal PH has attracted much attention. Here we provide an update on the ongoing research regarding the epigenetic regulation of the insulin growth factor (IGF)-1/IGF-1 receptor pathway, with insight into the potential regulatory role such regulation in the pathogenesis of neonatal PH.

Pathophysiology of infantile pulmonary arterial hypertension induced by monocrotaline

Pediatric pulmonary arterial hypertension (PAH) presents certain specific features. In this specific age group, experimental models to study the pathophysiology of PAH are lacking. To characterize hemodynamic, morphometric, and histological progression as well as the expression of neurohumoral factors and regulators of cardiac transcription in an infantile model of PAH induced by monocrotaline (MCT), eight-day-old Wistar rats were randomly injected with MCT (30 mg/kg, sc, n = 95) or equal volume of saline solution (n = 92). Animals were instrumented for biventricular hemodynamic recording 7, 14, and 21 days after MCT, whereas samples were collected at 1, 3, 7, 14, and 21 days after MCT. Different time point postinjections were defined for further analysis. Hearts and lungs were collected for morphometric characterization, assessment of right- and left-ventricle (RV and LV) cardiomyocyte diameter and collagen type-I and type-III ratio, RV collagen volume fraction, and pulmonary vessels wall thickness. mRNA quantification was undertaken for brain natriuretic peptide (BNP), endothelin-1 (ET-1), and for cardiac transcription regulators (HOP and Islet1). Animals treated with MCT at the 8th day of life presented RV hypertrophy since day 14 after MCT injection. There were no differences on the RV collagen volume fraction or collagen type-I and type-III ratio. Pulmonary vascular remodelling and PAH were present on day 21, which were accompanied by an increased expression of BNP, ET-1, HOP, and Islet1. The infantile model of MCT-induced PAH can be useful for the study of its pathophysiology and to test new therapeutic targets in pediatric age group.

Mortality associated with pulmonary hypertension in congenital rubella syndrome

OBJECTIVE

Outbreaks of rubella and congenital rubella syndrome (CRS) continue to arise in various countries where a rubella-containing vaccine is not included in the national immunization program. After a large-scale rubella outbreak in 2011, CRS cases emerged in Vietnam. The aim of this study was to clarify the clinical features of these cases with an emphasis on cardiovascular complications and outcomes.

METHODS

From October 2011 to September 2012, we conducted a prospective surveillance study of infants <12 months of age who had manifestations suggesting CRS at the only referral hospital in Khanh Hoa Province. These infants underwent standard examinations, echocardiography, cranial ultrasonography, automated auditory brainstem responses, blood cell count measurements, and rubella-specific antibody testing. Detected cardiovascular defects were regularly followed with echocardiography.

RESULTS

We enrolled 38 cases of CRS characterized by a low birth weight (71%), cardiovascular defects (72%), cataracts (13%), hearing impairment (93%), purpura (84%), hepatosplenomegaly (68%), and thrombocytopenia (76%). Patent ductus arteriosus, the most common cardiovascular complication, was often associated with progressive pulmonary hypertension (PH). As of January 2013, 13 infants (34%) had died, and PH was significantly more frequent among the fatalities (P = .004); however, therapeutic closure of the ductus reversed the PH in several cases.

CONCLUSIONS

PH-associated mortality is high among infants who have CRS in Vietnam. Providing proper assessments, continuous follow-up, and timely intervention for cardiovascular defects is critical for the management of CRS patients. Echocardiography is of diagnostic and prognostic value and can support better clinical management of CRS, even in a developing country setting.

B-type natriuretic peptide inhibits angiotensin II-induced proliferation and migration of pulmonary arterial smooth muscle cells

Pulmonary vascular remodeling, characterized by disordered proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), is a pathognomonic feature of pulmonary arterial hypertension. Thus, pharmacologic strategy targeting on anti-proliferation and anti-migration of PASMCs may have therapeutic implications for PAH. Here we investigated the effects and underlying mechanisms of B-type natriuretic peptide (BNP) on angiotensin II (Ang II)-induced proliferation and migration of PASMCs. Proliferation and migration of PASMCs cultured from Wistar rats were induced by Ang II, with or without BNP treatment. In addition, potential underlying mechanisms including cell cycle progression, Ca(2+) overload, reactive oxygen species (ROS) production, signal transduction of MAPK and Akt, and the cGMP/PKG pathway were examined. We found that BNP inhibited Ang II-induced PASMCs proliferation and migration dose dependently. BNP could also arrest the cell cycle progression in the G0/G1-phase. In addition, BNP attenuated intracellular calcium overload caused by Ang II. Moreover, Ang II-induced ROS production was mitigated by BNP, with associated down-regulation of NAD(P)H oxidase 1 (Nox1) and reduced mitochondrial ROS production. Finally, Ang II-activated MAPKs and Akt were also counteracted by BNP. Of note, all these effects of BNP were abolished by a PKG inhibitor (Rp-8-Br-PET-cGMPS). In conclusion, BNP inhibits Ang II-induced PASMCs proliferation and migration. These effects are potentially mediated by decreased calcium influx, reduced ROS production by Nox1 and mitochondria, and down-regulation of MAPK and Akt signal transduction, through the cGMP/PKG pathway. Therefore, this study implicates that BNP may have a therapeutic role in pulmonary vascular remodeling.

Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Pulmonary hypertension in children

Pulmonary hypertension (PH) is relatively uncommon in children. Pulmonary arterial hypertension (PAH) in pediatric comprises a wide spectrum of diseases, from a transient neonatal condition to a progressive disease associated with morbidity and mortality. Most common PAH in pediatric are idiopathic (IPAH) or PAH associated with congenital heart disease (PAH-CHD), while other associated conditions, such as connective tissue disease (CTD), are less common in pediatrics. Despite better understanding of PH and the availability of new medications during recent decades; the diagnosis, investigation and choice of therapy remain a challenge in children, as evidence-based recommendations depend mainly on adult studies. In this review, we provide a detailed discussion about the distinctive features of PAH in pediatric, mainly emphacysing on classification and diagnostic algorithm.

Current and advancing treatments for pulmonary arterial hypertension in childhood

Pulmonary arterial hypertension (PAH) is a severe and progressive intrinsic disease of the precapillary lung vasculature. Since the introduction of PAH-targeted drugs, survival of PAH patients seems to have improved. Randomized controlled trials have led to evidence-based guidelines to direct treatment in adults. However, since disease characteristics differ between adults and children, it is hazardous to simply extrapolate these guidelines to children. Moreover, pediatric data on treatment strategies and how to assess treatment response remain virtually absent. Optimal treatment strategies are highly needed to guide therapy and improve survival in children with PAH. This review provides an overview of currently available treatments for PAH and the limited efficacy and safety data in children (with the exclusion of perinatal pulmonary vascular diseases, as persistent pulmonary hypertension of the newborn). We also discuss potential treatment goals and how the available data can be translated into treatment strategies in pediatric PAH.

Right ventricular diastolic performance in children with pulmonary arterial hypertension associated with congenital heart disease: correlation of echocardiographic parameters with invasive reference standards by high-fidelity micromanometer catheter

BACKGROUND

Right ventricular diastolic dysfunction influences outcomes in pulmonary arterial hypertension (PAH), but echocardiographic parameters have not been investigated in relation to invasive reference standards in pediatric PAH. We investigated echocardiographic parameters of right ventricular diastolic function in children with PAH in relation to simultaneously measured invasive reference measures.

METHODS AND RESULTS

We prospectively recruited children undergoing a clinically indicated cardiac catheterization for evaluation of PAH and pulmonary vasoreactivity testing. Echocardiography was performed simultaneously with invasive reference measurements by high-fidelity micromanometer catheter. For analysis, patients were divided into shunt and nonshunt groups. Sixteen children were studied. In the group as a whole, significant correlations were found among τ and tricuspid deceleration time, E', E/E', TimeE-E', A wave velocity, and global early and late diastolic strain rate. dp/dt minimum correlated significantly with late diastolic tricuspid annular velocity (A'), tissue Doppler imaging-derived systolic:diastolic duration ratio, and global late diastolic strain rate. End-diastolic pressure correlated significantly with tissue Doppler imaging-derived systolic:diastolic duration ratio. On multivariate analysis, tricuspid deceleration time, TimeE-E', and global early diastolic strain rate were independent predictors of τ, whereas tissue Doppler imaging-derived systolic:diastolic duration ratio was an independent predictor of dp/dt minimum. In general, correlations between echocardiographic and invasive parameters were better in the shunt group than in the nonshunt group.

CONCLUSIONS

Echocardiography correlates with invasive reference measures of right ventricular diastolic function in children with PAH, although it does not differentiate between early versus late diastolic abnormalities. Newer echocardiographic techniques may have added value to assess right ventricular diastolic dysfunction in this population.

Biomarkers for pediatric pulmonary arterial hypertension - a call to collaborate

Therapeutic approaches in pediatric pulmonary arterial hypertension (PAH) are based primarily on clinician experience, in contrast to the evidence-based approach in adults with pulmonary hypertension. There is a clear and present need for non-invasive and objective biomarkers to guide the accurate diagnosis, treatment, and prognosis of this disease in children. The multifaceted spectrum of disease, clinical presentation, and association with other diseases makes this a formidable challenge. However, as more progress is being made in the understanding and management of adult PAH, the potential to apply this knowledge to children has never been greater. This review explores the state of the art with regard to non-invasive biomarkers in PAH, with an eye toward those adult PAH biomarkers potentially suitable for application in pediatric PAH.

Platelet distribution width and mean platelet volume in children with pulmonary arterial hypertension secondary to congenital heart disease with left-to-right shunt: new indices of severity?

The majority of patients with congenital heart disease (CHD), particularly those with relevant systemic-to-pulmonary shunts, if left untreated, will experience the development of pulmonary arterial hypertension (PAH). Previous studies have shown that platelet activation occurs in patients with PAH. In response, this study aimed to investigate the platelet indices, including platelet distribution width (PDW) and mean platelet volume (MPV), in patients with PAH. The study was conducted in the pediatrics cardiology unit of Selcuk University Medical Faculty between July 2010 and January 2012. The patients' clinical and laboratory data were obtained retrospectively from hospital recordings. The study enrolled 57 children with CHD (all with left-to-right shunting). The patients who had undergone diagnostic cardiac catheterization were analyzed according to the presence or absence of PAH. Group 1 had CHD with PAH, and group 2 had CHD without PAH. Compared with the group 2 patients, a significant decrease in PDW (p < 0.0001) was noted in the group 1 patients (with PAH). Likewise, a significant difference was found in the MPV of group 1 (p < 0.0001). Statistically, groups 1 and 2 did not differ in terms of platelet count (p = 0.3). Patients who had pulmonary hypertension secondary to CHD with left-to-right shunting exhibited a lower PDW and MPV.

Children with pulmonary arterial hypertension and prostanoid therapy: long-term hemodynamics

BACKGROUND

Pediatric patients with severe pulmonary arterial hypertension (PAH) are treated with intravenous epoprostenol or intravenous or subcutaneous treprostinil. Little is known about longitudinal hemodynamics and outcomes of epoprostenol, treprostinil, and transitions from epoprostenol to treprostinil.

METHODS

This was retrospective study of 77 pediatric patients (47 idiopathic PAH, 24 congenital heart disease-PAH) receiving epoprostenol or treprostinil from 1992 to 2010 at 2 centers. Outcomes were defined as living vs dead/transplant.

RESULTS

Mean age at baseline was 7.7 ± 5.2 years, with follow-up of 4.3 ± 3.4 years. Thirty-seven patients were treated with epoprostenol, 20 with treprostinil, and 20 were transitioned from epoprostenol to treprostinil. Mean pulmonary-to-systemic vascular resistance ratio (Rp/Rs) for epoprostenol was 1.0 ± 0.4, 0.8 ± 0.4, 0.8 ± 0.4, 1.0 ± 0.4, and 1.2 ± 0.4, respectively, at baseline, 1, 2, 3, and 4 years. For treprostinil, Rp/Rs was 0.9 ± 0.3, 0.7 ± 0.3, 0.5 ± 0.2, (p < 0.01 vs baseline), and 1.1 ± 0.2, respectively, at baseline, 1, 2, and 3 to 4 years, respectively. There were similar changes in mean pulmonary artery pressure and pulmonary vascular resistance index. The Rp/Rs 1 year after epoprostenol to treprostinil transition increased from 0.6 to 0.8 (n = 7). Changes not statistically significant unless noted. Eight patients died or received a transplant within 2 years of baseline; compared with the rest of the cohort, mean baseline Rp/Rs, right atrial pressure, and pulmonary vascular resistance index were significantly worse in this group. Thirty-nine patients remain on prostanoids, 17 are off, 16 died, and 5 received heart-lung transplant. Kaplan-Meier 5-year transplant-free survival was 70% (95% confidence interval, 56%-80%).

CONCLUSION

There was improvement in Rp/Rs on both therapies at 1 to 2 years that was not sustained. The 5-year transplant-free survival was better than in similar adult studies.

Review of inhaled nitric oxide in the pediatric cardiac surgery setting

Surgical intervention for congenital heart disease (CHD) can be complicated by pulmonary hypertension (PH), which increases morbidity, mortality, and medical burden. Consequently, postoperative management of PH is an important clinical consideration to improve outcomes. Inhaled nitric oxide (iNO) is a widely accepted standard of care for PH and has been studied in the context of cardiac surgery for CHD. However, large randomized, double-blind, placebo-controlled, multicenter clinical trials in pediatric patients are limited. This review will provide an overview of the clinical studies in this setting and will discuss general treatment considerations to facilitate a better understanding of the clinical use of iNO for PH after pediatric cardiac surgery.

Bilateral lung transplantation for pediatric idiopathic pulmonary arterial hypertension: a multi-center experience

Many children with idiopathic pulmonary arterial hypertension (IPAH) experience disease progression despite advanced medical therapy. In these children, heart-lung or bilateral lung transplantation (BLTx) remain the only therapeutic options when other treatments fail. Data on functional outcome after BLTx in children with IPAH are limited. We report a multi-center experience of BLTx for pediatric IPAH. We performed a retrospective study including 25 centers within the International Pediatric Lung Transplant Collaborative. Children with IPAH who underwent BLTx were included (1996-2006). Twenty-three children underwent BLTx for IPAH, most of whom were in WHO class III or IV level of function pre-transplantation. At 6 months post-transplantation, 82% of children reported improvement in level of function to WHO class I. The median FEV(1) was 89% (12-126) of predicted at 12 months post-transplantation. Ten patients (44%) developed BOS at a median of 42 months (3-85), of whom five died at a median of 27 months (4-86) post-transplantation. Overall mortality was 4% at 3 months post-transplantation. The median survival for children in this cohort was 45 months (2-123). Our data suggest that BLTx is a valuable therapeutic option for children with end-stage IPAH with outcomes comparable to that after heart-lung transplantation in children with pulmonary arterial hypertension or those patients undergoing lung transplantation for other indications. In the majority of children, a good cardiopulmonary function is possible following BLTx, making BLTx a good therapeutic option and maximizing donor organ utilization by allowing more hearts to be available for children needing cardiac transplantation.

Pulmonary arterial capacitance in children with idiopathic pulmonary arterial hypertension and pulmonary arterial hypertension associated with congenital heart disease: relation to pulmonary vascular resistance, exercise capacity, and survival

BACKGROUND

Pediatric pulmonary arterial hypertension (PAH), whether idiopathic PAH (iPAH) or PAH associated with congenital heart disease (aPAH), carries high morbidity and mortality. Low pulmonary arterial capacitance (PAC), defined as right ventricular stroke volume/pulmonary artery pulse pressure, is a risk factor for mortality in adults with PAH. However, the relation of PAC to pulmonary vascular resistance (PVR), exercise endurance, and survival is poorly defined in children.

METHODS

Catheterization and clinical data of children with PAH (mean pulmonary artery pressure >25 mm Hg) were reviewed. Children with pulmonary shunts, stents, collaterals, or pulmonary venous hypertension were excluded. Primary outcomes were 6-minute walk distance and freedom from death/lung transplant.

RESULTS

Forty-seven patients were studied. Nineteen (43%) had iPAH, and 28 (57%) had aPAH (7.1 ± 6.2 vs 8.4 ± 5.5 years, P = .45). Patients with iPAH had higher PVR indexed for body surface area (PVRi), lower indexed PAC (PACi), lower exercise tolerance, and lower freedom from death/lung transplant than patients with aPAH. Both higher PVRi (P < .0001) and lower PACi (P = .02) were associated with shorter 6-minute walk distance. A PACi <0.70 mL/mm Hg per square meter or >1.25 mL/mm Hg per square meter and a PVRi >13 Wood units × m(2) were associated with decreased freedom from death or lung transplant. The relationships between PVRi and PACi and survival were independent of each other and not confounded by etiologic group.

CONCLUSIONS

Low PACi and high PVRi are independently associated with low 6-minute walk distance and survival in children with PAH. Therefore, both should be assessed for better prognostication and management in this high-risk population.

Treatment of pediatric pulmonary hypertension with simvastatin: an observational study

BACKGROUND

Animal studies and an adult human case series suggest that statins may have a role in the treatment of pulmonary hypertension. We reviewed the results of empirical therapy for children at Primary Children's Medical Center to determine whether simvastatin had a favorable effect on non-invasive estimates of pulmonary arterial pressure.

MATERIALS AND METHODS

The medical records of children with pulmonary hypertension who were treated with simvastatin were reviewed. Mean measurements of the gradient of tricuspid valve regurgitation before and after treatment were compared by a paired t-test. A favorable response to simvastatin was defined as a 20% decrease in the average measurement of the gradient of tricuspid valve regurgitation or a 20% decrease in right ventricular anterior wall thickness when tricuspid valve regurgitation resolved during treatment. Potential factors associated with a favorable response to simvastatin were identified with a Fisher exact test.

RESULTS

Twelve children, 4-15 years of age, had adequate Doppler velocity waveforms to reliably measure gradients of tricuspid valve regurgitation during a period of 1 year before treatment. Eleven patients had gradients of tricuspid valve regurgitation that could be measured during a period of 1 year after treatment. Patients were treated with simvastatin 0.09-0.28 mg/kg/day. Collectively, there was no difference between the average measurements of the gradient of tricuspid valve regurgitation before and after treatment (66 ± 21 mmHg vs. 63 ± 28 mmHg). Three of the five patients with clinical findings consistent with alveolar hypoxia and none of the seven patients without clinical findings consistent with alveolar hypoxia had a favorable response to treatment with simvastatin (P = 0.05).

CONCLUSION

Simvastatin may decrease pulmonary arterial pressure in a subset of patients with pulmonary hypertension.

Pulmonary arterial hypertension: a comparison between children and adults

The characteristics of pulmonary arterial hypertension (PAH), including pathology, symptoms, diagnosis and treatment are reviewed in children and adults. The histopathology seen in adults is also observed in children, although children have more medial hypertrophy at presentation. Both populations have vascular and endothelial dysfunction. Several unique disease states are present in children, as lung growth abnormalities contribute to pulmonary hypertension. Although both children and adults present at diagnosis with elevations in pulmonary vascular resistance and pulmonary artery pressure, children have less heart failure. Dyspnoea on exertion is the most frequent symptom in children and adults with PAH, but heart failure with oedema occurs more frequently in adults. However, in idiopathic PAH, syncope is more common in children. Haemodynamic assessment remains the gold standard for diagnosis, but the definition of vasoreactivity in adults may not apply to young children. Targeted PAH therapies approved for adults are associated with clinically meaningful effects in paediatric observational studies; children now survive as long as adults with current treatment guidelines. In conclusion, there are more similarities than differences in the characteristics of PAH in children and adults, resulting in guidelines recommending similar diagnostic and therapeutic algorithms in children (based on expert opinion) and adults (evidence-based).

Usefulness of the right ventricular systolic to diastolic duration ratio to predict functional capacity and survival in children with pulmonary arterial hypertension

The objective of this study was to investigate the systolic to diastolic duration ratio (S:D ratio) in children with pulmonary arterial hypertension (PAH) and its association with right ventricular (RV) performance, hemodynamics, 6-minute walk test, clinical outcomes, and survival. We reviewed 503 serial echocardiograms in 47 children with PAH (mean pulmonary artery pressure >or=25 mm Hg) and compared the S:D ratio, assessed from Doppler flow of tricuspid valve regurgitation, to that in 47 age-matched controls. We reviewed echocardiograms, catheterization data, 6-minute walk tests, clinical data, lung transplantation, and death and used univariate linear regression models with a maximum likelihood algorithm for parameter estimation to investigate associations between S:D ratio and RV function, hemodynamics, functional capacity, and clinical outcomes. The S:D ratio was significantly higher in patients than in controls (1.38 +/- 0.61 vs 0.72 +/- 0.16, p <0.001). A higher S:D ratio was associated with worse echocardiographic RV fractional area of change, worse catheterization hemodynamics, shorter 6-minute walk distance, and worse clinical outcomes independent of pulmonary resistance or pressures. An increase of 0.1 in the S:D ratio was associated with a 13% increase in yearly risk for lung transplantation or death (hazard ratio 1.13, p <0.001). An S:D ratio 1.00 to 1.40 was associated with a moderate risk and an S:D ratio >1.40 was associated with a high risk of a negative outcome. In conclusion, in children with PAH, an increased S:D ratio is temporally associated with worse RV function, hemodynamics, exercise capability, clinical status, and survival.

Advances in therapies for pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by progressive obliteration of the pulmonary vasculature, leading to right heart failure and death if left untreated. Prior to the current treatment era, pulmonary hypertension carried a poor prognosis with a high mortality rate, but its prognosis has changed over the past decades in relation to new therapeutic agents. Nevertheless, pulmonary hypertension continues to be a serious condition, which is extremely challenging to manage. The data in children are often limited owing to the small number of patients, and extrapolation from adults to children is not straightforward. While none of these new therapeutic agents have been specifically approved for children, there is evidence that each can appropriately benefit the PAH child. We review the current understanding of pediatric pulmonary hypertension, classification, diagnostic evaluation and available treatment. A description of targeted pharmacological therapy and new treatments in children is outlined.

Diagnostic strategies for acute presentation of pulmonary hypertension in children: particular focus on use of echocardiography, cardiac catheterization, magnetic resonance imaging, chest computed tomography, and lung biopsy

Determining the etiology of pediatric pulmonary hypertension is essential to appropriate management. Assessment of the patient requires complete history and physical examination as well as the use of investigative modalities including echocardiography, cardiac catheterization, cardiac magnetic resonance imaging (MRI), chest computed tomography, and lung biopsy. This review summarizes recommendations for diagnostic work-up and includes a clinical algorithm for evaluation of the patient with acute pulmonary hypertension in the pediatric intensive care unit.

Severe pulmonary hypertension associated with the acute motor sensory axonal neuropathy subtype of Guillain-Barré syndrome

OBJECTIVE

To evaluate pulmonary hypertension associated with acute motor sensory axonal neuropathy subtype of Guillain-Barré syndrome. Guillain-Barré syndrome consists of a group of autoimmune disorders that generally manifest as symmetric, progressive, ascending paralysis. There are five subtypes of Guillain-Barré syndrome, and autonomic involvement has been described in all subtypes, including cardiovascular, vasomotor, or pseudomotor dysfunction of both the sympathetic and parasympathetic systems.

DESIGN

Case report.

SETTING

Tertiary care pediatric intensive care unit.

PATIENT

Three-yr-old female patient.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Serial measurements of pulmonary artery pressure. We report the case of a young girl with acute motor sensory axonal neuropathy who presented with severe cardiovascular collapse secondary to severe pulmonary hypertension. In this patient, multiple factors may have played a role in the development of pulmonary hypertension including autonomic dysfunction, hypoventilation, and immobility as a risk for thrombosis and pulmonary emboli.

CONCLUSION

It is possible that many other individuals suffering from severe forms of Guillain-Barré syndrome, especially those with significant autonomic dysfunction, may actually have undiagnosed and therefore untreated pulmonary hypertension. Therefore, it is recommended that clinicians caring for critically ill children with Guillain-Barré syndrome have a high index of suspicion for pulmonary hypertension and consider echocardiography if there are clinical signs of this potentially fatal process.