Advances in pediatric pulmonary arterial hypertension

Right ventricular-vascular coupling ratio in pediatric pulmonary arterial hypertension: A comparison between cardiac magnetic resonance and right heart catheterization measurements

BACKGROUND

In pulmonary arterial hypertension (PAH), right ventricular (RV) failure is the main cause of mortality. Non-invasive estimation of ventricular-vascular coupling ratio (VVCR), describing contractile response to afterload, could be a valuable tool for monitoring clinical course in children with PAH. This study aimed to test two hypotheses: VVCR by cardiac magnetic resonance (VVCR_CMR) correlates with conventional VVCR by right heart catheterization (VVCR_RHC) and both correlate with disease severity.

METHODS AND RESULTS

Twenty-seven patients diagnosed with idiopathic and associated PAH without post-tricuspid shunt, who underwent RHC and CMR within 17 days at two specialized centers for pediatric PAH were retrospectively studied. Clinical functional status and hemodynamic data were collected. Median age at time of MRI was 14.3 years (IQR: 11.1-16.8), median PVRi 7.6 WU × m² (IQR: 4.1-12.2), median mPAP 40 mm Hg (IQR: 28-55) and median WHO-FC 2 (IQR: 2-3). VVCR_CMR, defined as stroke volume/end-systolic volume ratio was compared to VVCR_RHC by single-beat pressure method using correlation and Bland-Altman plots. VVCR_CMR and VVCR_RHC showed a strong correlation (r = 0.83, p < 0.001). VVCR_CMR and VVCR_RHC both correlated with clinical measures of disease severity (pulmonary vascular resistance index [PVRi], mean pulmonary artery pressure [mPAP], mean right atrial pressure [mRAP], and World Health Organization functional class [WHO-FC]; all p ≤ 0.02).

CONCLUSIONS

Non-invasively measured VVCR_CMR is feasible in pediatric PAH and comparable to invasively assessed VVCR_RHC. Both correlate with functional and hemodynamic measures of disease severity. The role of VVCR assessed by CMR and RHC in clinical decision-making and follow-up in pediatric PAH warrants further clinical investigation.

Hospital Readmissions in Children with Pulmonary Hypertension: A Multi-Institutional Analysis

OBJECTIVE

To assess the rate of and risk factors for 30-day hospital readmission in children with pulmonary hypertension.

STUDY DESIGN

The Pediatric Health Information System database was analyzed for patients ≤18 years old with pulmonary hypertension (International Classification of Diseases, Ninth Revision, diagnosis codes of 416.0, 416.1, 416.8, or 416.9) admitted from 2005 through 2014. A generalized hierarchical regression model was used to determine significant ORs and 95% CIs associated with 30-day readmission.

RESULTS

A total of 13580 patients met inclusion criteria (median age 1.7 years [IQR 0.3-8.7], 45.3% with congenital heart disease). Admissions increased 4-fold throughout the study period. Associated hospital charges increased from $119 million in 2004 to $929 million in 2014. During initial admission, 57.4% of patients required admission to the intensive care unit, and 48.2% required mechanical ventilation. The 30-day readmission rate was 26.3%. Mortality during readmission was 4.2%. Factors increasing odds of readmission included a lower hospital volume of pulmonary hypertension admissions (1.41 [1.23-1.57], P < .001) and having public insurance (1.26 [1.16-1.38], P < .001). Decreased odds of readmission were associated with older age and the presence of congenital heart disease (0.86 [0.79-0.93], P < .001).

CONCLUSIONS

The pediatric pulmonary hypertension population carries significant morbidity, as reflected by a high use of intensive care unit resources and a high 30-day readmission rate. Younger patients and those with public insurance represent particularly at-risk groups.

Pulmonary Hypertension Therapy and a Systematic Review of Efficacy and Safety of PDE-5 Inhibitors

Pulmonary hypertension (PH) is a syndrome that is of growing concern to pediatricians worldwide. Recent data led to concerns about the safety of phosphodiesterase type 5 (PDE5) inhibitors in children and a US Food and Drug Administration safety advisory. Our objective is to provide insight into therapies for PH in children and to systematically review the comparative effectiveness and safety of PDE5 inhibitors in the management of pediatric patients with PH. We searched the following databases through February 2015: Medline, Embase, SCOPUS, and the Cochrane Central Register of Controlled Trials. We included studies that examined PDE5 inhibitor use in children with PH. Allowed comparators were either no medication or other classes of medication for management of PH. Study inclusion was via a 2-stage process with 2 reviewers and a predesigned form. Of 1270 papers identified by the literature search, 21 were included: 8 randomized controlled trials and 13 observational studies (9 retrospective, 4 prospective). There is strong evidence that PDE5 inhibitor use improves echocardiography measurements, cardiac catheterization parameters, and oxygenation compared with baseline or placebo in pediatric patients with PH. Evidence suggests that low- and moderate-dose sildenafil are safe regimens for children. There are a relatively small number of randomized controlled trials that address use of PDE5 inhibitors in pediatric patients with PH. PDE5 inhibitors are effective agents for cardiovascular and oxygenation end points in pediatric PH and important components of a multimodal pharmacotherapeutic approach to this growing challenge. Additional studies are needed to define optimal PH therapy in childhood.

Continuous inhaled iloprost in a neonate with d-transposition of the great arteries and severe pulmonary arterial hypertension

This report describes the case of a neonate with d-transposition of the great arteries and severe pulmonary arterial hypertension stabilised in the post-operative period with continuous iloprost nebulisation. To our knowledge, this is the first documented method of treating post-operative severe pulmonary arterial hypertension with continuous inhaled iloprost in a patient with complex CHD. We found this method of delivering the drug very effective in stabilising haemodynamic swings in the setting of severe pulmonary arterial hypertension.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Pulmonary Hypertension

OBJECTIVE

To review the pharmacologic treatment options for pulmonary arterial hypertension in the cardiac intensive care setting and summarize the most-recent literature supporting these therapies.

DATA SOURCES AND STUDY SELECTION

Literature search for prospective studies, retrospective analyses, and case reports evaluating the safety and efficacy of pulmonary arterial hypertension therapies.

DATA EXTRACTION

Mechanisms of action and pharmacokinetics, treatment recommendations, safety considerations, and outcomes for specific medical therapies.

DATA SYNTHESIS

Specific targeted therapies developed for the treatment of adult patients with pulmonary arterial hypertension have been applied for the benefit of children with pulmonary arterial hypertension. With the exception of inhaled nitric oxide, there are no pulmonary arterial hypertension medications approved for children in the United States by the Food and Drug Administration. Unfortunately, data on treatment strategies in children with pulmonary arterial hypertension are limited by the small number of randomized controlled clinical trials evaluating the safety and efficacy of specific treatments. The treatment options for pulmonary arterial hypertension in children focus on endothelial-based pathways. Calcium channel blockers are recommended for use in a very small, select group of children who are responsive to vasoreactivity testing at cardiac catheterization. Phosphodiesterase type 5 inhibitor therapy is the most-commonly recommended oral treatment option in children with pulmonary arterial hypertension. Prostacyclins provide adjunctive therapy for the treatment of pulmonary arterial hypertension as infusions (IV and subcutaneous) and inhalation agents. Inhaled nitric oxide is the first-line vasodilator therapy in persistent pulmonary hypertension of the newborn and is commonly used in the treatment of pulmonary arterial hypertension in the ICU. Endothelin receptor antagonists have been shown to improve exercise tolerance and survival in adult patients with pulmonary arterial hypertension. Soluble guanylate cyclase stimulators are the first drug class to be Food and Drug Administration approved for the treatment of chronic thromboembolic pulmonary hypertension.

CONCLUSIONS

Literature and data supporting the safe and effective use of pulmonary arterial hypertension therapies in children in the cardiac intensive care are limited. Extrapolation of adult data has afforded safe medical treatment of pulmonary hypertension in children. Large multicenter trials are needed in the search for safe and effective therapy of pulmonary hypertension in children.

The Role of Biomarkers and Surrogate End Points in Drug Development for Neonatal Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease in newborns, infants, and children. It is associated with significant morbidity and mortality, but has limited treatment options. Except for inhaled nitric oxide, which is approved for persistent pulmonary hypertension of the newborn (PPHN), no drug is approved for the treatment of newborns, infants, and children with PAH. The lack of developmentally appropriate pediatric efficacy end points and pediatric clinical trials contribute to this unmet medical need. The noninvasive biomarkers reported in the literature that can be used as potential surrogate end points to assess disease severity and treatment response in neonates, infants, and children with PAH are reviewed herein. In addition, the role of the US Food and Drug Administration in developing potential biomarkers as surrogate end points to facilitate drug development for the treatment of children with PPHN and PAH in children is reviewed herein.

Pulmonary Hypertension in Children - a Practical Approach

Pulmonary hypertension (PH) is mean pulmonary arterial pressure above 25 mmHg at rest. Although considered a rare disease, the prevalence of PH in certain risk groups is higher, from 0.5% in patients with HIV infection to 30% in congenital heart disease (CHD) associating PH. In pulmonary arterial hypertension (PAH) associated with CHD, early changes of the vascular bed are reversible after correction of the defect, but there is a point from where the disease becomes irreversible or progression continues despite correction. Among patients with "operable" and "inoperable" CHD, there is a "gray area" group in between, which is defined by pulmonary vascular resistance equal to 4-8 WU/m and ratio of pulmonary vascular resistance to systemic vascular resistance of 0.3-0.5, measured by cardiac catheterization. In this situation a pulmonary vasoreactivity test is indicated. Pulmonary hypertension is a severe disease with increased morbidity and mortality. Pulmonary hypertension can result in death by decreased cardiac output, and heart failure.

Trends in pediatric pulmonary hypertension-related hospitalizations in the United States from 2000-2009

There are few data on the epidemiology of pulmonary hypertension (PH)-related hospitalizations in children in the United States. Our aim was to determine hospital mortality, length of hospitalization, and hospital charges pertaining to PH-related hospitalizations and also the effects of codiagnoses and comorbidities. A retrospective review of the Kids' Inpatient Database during the years 2000, 2003, 2006, and 2009 was analyzed for patients ≤20 years of age with a diagnosis of PH by ICD-9 (International Classification of Diseases, Ninth Revision) codes, along with associated diagnoses and comorbidities. Descriptive statistics, including Rao-Scott χ(2), ANOVA, and logistic regression models, were utilized on weighted values with survey analysis procedures. The number of PH-related hospital admissions is rising, from an estimated 7,331 (95% confidence interval [CI]: 5,556-9,106) in 2000 to 10,792 (95% CI: 8,568-13,016) in 2009. While infant age and congenital heart disease were most commonly associated with PH-related hospitalizations, they were not associated with mortality. Overall mortality for PH-related hospitalizations was greater than that for hospitalizations not associated with PH, 5.7% versus 0.4% (odds ratio: 16.22 [95% CI: 14.78%-17.8%], P < 0.001), but mortality is decreasing over time. Sepsis, respiratory failure, acute renal failure, hepatic insufficiency, arrhythmias, and the use of extracorporeal membrane oxygenation are associated with mortality. The number of PH-related hospitalizations is increasing in the United States. The demographics of PH in this study are evolving. Despite the increasing prevalence, mortality is improving.

Serum Pentraxin 3 and hs-CRP Levels in Children with Severe Pulmonary Hypertension

BACKGROUND

Pulmonary arterial hypertension secondary to untreated left-to-right shunt defects leads to increased pulmonary blood flow, endothelial dysfunction, increased pulmonary vascular resistance, vascular remodelling, neointimal and plexiform lesions. Some recent studies have shown that inflammation has an important role in the pathophysiology of pulmonary arterial hypertension.

AIMS

The aim of this study is to evaluate serum pentraxin 3 and high sensitive (hs)-C reactive protein (hs-CRP) levels in children with severe pulmonary arterial hypertension (PAH) secondary to untreated congenital heart defects and evaluate the role of inflammation in pulmonary hypertension.

STUDY DESIGN

Cross sectional study.

METHODS

After ethics committee approval and receiving consent from parents, there were 31 children were selected for the study with severe PAH, mostly with a left-to-right shunt, who had been assessed by cardiac catheterisation and were taking specific pulmonary vasodilators. The control group consisted of 39 age and gender matched healthy children. After recording data about all the patients including age, gender, weight, haemodynamic studies and vasodilator testing, a physical examination was done for all subjects. Blood was taken from patients and the control group using peripheral veins to analyse serum Pentraxin 3, N-terminal pro-Brain Natriuretic Peptide (NT-ProBNP) and hs-CRP levels. Serum Pentraxin-3 levels were measured by enzyme linked immunosorbent assay (ELISA) and expressed as ng/mL. Serum hs-CRP levels were measured with an immunonephelometric method and expressed as mg/dL. The serum concentration of NT-proBNP was determined by a chemiluminescent immunumetric assay and expressed as pg/mL.

RESULTS

Serum Pentraxin- 3 levels were determined to be 1.28±2.12 (0.12-11.43) in the PAH group (group 1) and 0.40±0.72 (0.07-3.45) in group 2. There was a statistically significant difference between the two groups (p<0.01). Serum hs-CRP levels were measured as 2.92±2.12 (0.32-14.7) mg/dL in group 1 and 0.35±0.16 (0.07-3.45) mg/dL in group 2. The hs-CRP level was increased in the PAH group to a significant degree (p<0.01).

CONCLUSION

Our study showed that pentraxin 3 and hs-CRP levels were increased significantly in the PAH group. We consider that inflammation plays an important role in severe pulmonary hypertension and progressive pulmonary arterial hypertension in children with PAH.

Perioperative pharmacological management of pulmonary hypertensive crisis during congenital heart surgery

Pulmonary hypertensive crisis is an important cause of morbidity and mortality in patients with pulmonary arterial hypertension secondary to congenital heart disease (PAH-CHD) who require cardiac surgery. At present, prevention and management of perioperative pulmonary hypertensive crisis is aimed at optimizing cardiopulmonary interactions by targeting prostacyclin, endothelin, and nitric oxide signaling pathways within the pulmonary circulation with various pharmacological agents. This review is aimed at familiarizing the practitioner with the current pharmacological treatment for dealing with perioperative pulmonary hypertensive crisis in PAH-CHD patients. Given the life-threatening complications associated with pulmonary hypertensive crisis, proper perioperative planning can help anticipate cardiopulmonary complications and optimize surgical outcomes in this patient population.

Prenatal programming of pulmonary hypertension induced by chronic hypoxia or ductal ligation in sheep

Pulmonary hypertension of the newborn is caused by a spectrum of functional and structural abnormalities of the cardiopulmonary circuit. The existence of multiple etiologies and an incomplete understanding of the mechanisms of disease progression have hindered the development of effective therapies. Animal models offer a means of gaining a better understanding of the fundamental basis of the disease. To that effect, a number of experimental animal models are being used to generate pulmonary hypertension in the fetus and newborn. In this review, we compare the mechanisms associated with pulmonary hypertension caused by two such models: in utero ligation of the ductus arteriosus and chronic perinatal hypoxia in sheep fetuses and newborns. In this manner, we make direct comparisons between ductal ligation and chronic hypoxia with respect to the associated mechanisms of disease, since multiple studies have been performed with both models in a single species. We present evidence that the mechanisms associated with pulmonary hypertension are dependent on the type of stress to which the fetus is subjected. Such an analysis allows for a more thorough evaluation of the disease etiology, which can help focus clinical treatments. The final part of the review provides a clinical appraisal of current treatment strategies and lays the foundation for developing individualized therapies that depend on the causative factors.

The anesthetic management of children with pulmonary hypertension in the cardiac catheterization laboratory

Children need cardiac catheterization to establish the diagnosis and monitor the response to treatment when undergoing drug therapy for the treatment of pulmonary arterial hypertension (PAH). Children with PAH receiving general anesthesia for cardiac catheterization procedures are at significantly increased risk of perioperative complications in comparison with other children. The most acute life-threatening complication is a pulmonary hypertensive crisis. It is essential that the anesthesiologist caring for these children understands the pathophysiology of the disease, how anesthetic medications may affect the patient's hemodynamics, and how to manage an acute pulmonary hypertensive crisis.

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.

Long term cardiovascular consequences of chronic lung disease of prematurity

Pulmonary arterial (PA) hypertension in preterm infant is an important consequence of chronic lung disease of prematurity (CLD) arising mainly due to impaired alveolar development and dysregulated angiogenesis of the pulmonary circulation. Although PA pressure and resistance in these children normalise by school age, their pulmonary vasculature remains hyper-reactive to hypoxia until early childhood. Furthermore, there is evidence that systemic blood pressure in preterm born children with or without CLD is mildly increased at school age and in young adulthood when compared to term-born children. Arterial stiffness may be increased in CLD survivors due to increased smooth muscle tone of the pre-resistance and resistance vessels rather than the loss of elasticity in the large arteries. This review explores the long term effects of CLD on the pulmonary and systemic circulations along with their clinical correlates and therapeutic approaches.

Acute pulmonary vasodilator testing with inhaled treprostinil in children with pulmonary arterial hypertension

Acute pulmonary vasodilator testing (AVT) is essential to determining the initial therapy for children with pulmonary arterial hypertension (PAH). This study aimed to report the initial experience with inhaled treprostinil used for AVT in children with PAH and to evaluate the hemodynamic change after inhaled treprostinil compared with inhaled nitric oxide. This prospective cohort study was designed for 13 children who underwent AVT with inhaled treprostinil or oxygen plus inhaled nitric oxide (iNO) during catheterization. Inhaled treprostinil was delivered during cardiac catheterization by adapting the Optineb ultrasonic nebulizer via either a flow-inflating bag or the manual mode of the anesthesia system. The median age of the patients was 10 years (range 4-17 years). The etiologies of PAH included idiopathic PAH and associated PAH. All the patients tolerated inhaled treprostinil without marked clinical worsening and received six or nine breaths (36 or 54 μg) of treprostinil. The median of the total treprostinil doses was 1.53 μg/kg (range 0.71-2.89 μg/kg). Inhaled treprostinil was administrated via an endotracheal tube (n = 8), anesthesia mask (n = 3), or laryngeal mask airway (n = 2). Inhaled nitric oxide (iNO) and inhaled treprostinil significantly decreased the mean pulmonary artery pressure and the pulmonary vascular resistance index compared with baseline. Three adverse events were reported after inhaled treprostinil, including cough and mild to moderate hypotension with higher doses. All adverse events resolved without any intervention. This study report is the first to describe the use of inhaled treprostinil for AVT in children with PAH. In this small pediatric cohort, inhaled treprostinil was effectively delivered and well tolerated and may be useful for AVT.

Doppler tissue imaging provides an estimate of pulmonary arterial pressure in children with pulmonary hypertension due to congenital intracardiac shunts

OBJECTIVE

The aim of this study is to determine the relationship between the cardiac catheterization findings and pulsed-wave (PW) Doppler and Doppler tissue imaging (DTI) in pulmonary arterial hypertension patients with congenital heart disease with intracardiac shunts.

DESIGN AND PATIENTS

The present study aims to determine the relationship between the cardiac catheterization findings and PW Doppler and Doppler tissue imaging (DTI) in patients who have pulmonary arterial hypertension patients due to congenital heart disease with intracardiac shunts. Echocardiographic measurements were performed at the catheter angiography laboratory with concurrent catheterization. Left and right ventricle inflow velocities were recorded with PW Doppler and DTI studies. Maximum tricuspid regurgitation velocity (TS) was recorded in cases with measurable levels by continuous-wave Doppler. Moreover, the correlations among the echocardiographic values and invasive hemodynamic measures such as systolic pulmonary arterial pressure (PAPsystolic), mean pulmonary arterial pressure (PAPmean), diastolic pulmonary arterial pressure (PAPdiastolic) and pulmonary vascular resistance index (PVRI) were evaluated.

RESULTS

A negative correlation was found between TE'/TA' and PAPsystolic, PAPdiastolic and PAPmean (P = 0.008, r = -0.480; P = 0.001, r = -0.584; P = 0.001, r = -0.567, respectively). ME/ME' was also found to be negatively correlated with PAPdiastolic, PAPmean and PVRI (P = 0.002, r = -0.556; P = 0.005, r = -0.502; P = 0.027, r = -0.411, respectively). The concurrent use of TE'/TA' (cut-off value <2.6) and TS had a sensitivity of 79% and a specificity of 93% for distinguishing between patients with healthy controls.

CONCLUSION

When used in conjunction with conventional methods, TE'/TA' has the highest sensitivity and specificity in distinguishing between patients and healthy controls.

Circulating cytokines and growth factors in pediatric pulmonary hypertension

Background. Management of pediatric pulmonary hypertension (PH) remains challenging. We have assessed a panel of circulating proteins in children with PH to investigate their value as predictive and/or prognostic biomarkers. From these determinations, we aim to develop a practical, noninvasive tool to aid in the management of pediatric PH. Methods. Twelve cytokines and growth factors putatively associated with lung or vascular disease were examined in plasma specimens from 70 children with PH using multiplex protein array technology. Associations between hemodynamics, adverse events, and protein markers were evaluated. Results. Epidermal growth factor (EGF) and IL-6 were associated with important hemodynamics. Of the twelve proteins, VEGF and IL-6 were significantly, univariately associated with the occurrence of an adverse event, with odds ratios (95% confidence intervals) of 0.56 (0.33–0.98) and 1.69 (1.03–2.77), respectively. When hemodynamic predictors were combined with protein markers, the ability to predict adverse outcomes within the following year significantly increased. Conclusions. Specific circulating proteins are associated with hemodynamic variables in pediatric PH. If confirmed in additional cohorts, measurement of these proteins could aid patient care and design of clinical trials by identifying patients at risk for adverse events. These findings also further support a role for inflammation in pediatric PH.

Epidemiology and clinical management of pulmonary hypertension in children

Pulmonary hypertension (PH) is a clinical hemodynamic syndrome characterized by increased pulmonary artery pressure and pulmonary vascular resistance. It can cause right ventricular failure, and even death. Pediatric PH is not very common, but is a greatly hazardous disease that leads to a high mortality rate. Therefore, many registry organizations have been established in the world to strengthen the study of diagnosis and treatment of the disease, and improve the understanding of pediatric PH. This article reviewed recently published researches, as well as presented a comprehensive understanding of PH, including definition, classification, epidemiology, prognosis and treatment.

Pulmonary arterial hypertension in pediatric patients with hematopoietic stem cell transplant-associated thrombotic microangiopathy

Pulmonary arterial hypertension (PAH) is rarely included in the differential diagnosis of cardiorespiratory failure after pediatric hematopoietic stem cell transplant (HSCT) as the clinical presentation is nonspecific and may mimic other etiologies. The pathogenesis of PAH in HSCT is poorly understood and the diagnosis requires a high degree of suspicion. We describe 5 children diagnosed with PAH after allogeneic HSCT. All 5 patients had prolonged clinical signs of transplantation-associated thrombotic microangiopathy (TA-TMA) when they presented with hypoxemic respiratory failure and evidence of PAH. Four of the 5 patients had echocardiographic evidence of PAH, and 1 patient was diagnosed with PAH only on autopsy. PAH was diagnosed a median of 76 days (range, 56-101 days) after a diagnosis of TA-TMA. Despite aggressive medical management, including inhaled nitric oxide, 4 of the 5 patients died. One patient recovered from PAH after 11 months of sildenafil therapy. Three of the 4 deceased patients had an autopsy performed, demonstrating severe pulmonary vascular disease consistent with TA-TMA and severe PAH. We conclude that TA-TMA can be associated with significant pulmonary vascular injury presenting as hypoxemic respiratory failure with PAH after HSCT. Pediatric patients with unexplained hypoxemia after HSCT should be evaluated for both transplantation complications, TA-TMA and PAH, accordingly.