Bosentan for increased pulmonary vascular resistance in a patient with single ventricle physiology and a bidirectional Glenn shunt

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.

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.

Efficacy of endothelin blockade in adults with Fontan physiology

OBJECTIVE

Phosphodiesterase-5 inhibitors have shown to improve cardiac output and functional capacity in Fontan patients. We sought to test the efficacy and safety of endothelin blockade with bosentan in adult patients with Fontan physiology.

DESIGN

Ten patients were enrolled and seven patients completed this single-center open-label clinical trial. Patients were treated with bosentan for 4 months. Cardiac magnetic resonance imaging (MRI), 6-minute walking distance (6MWD), brain natriuretic peptide, and New York Heart Association functional class were compared before and after treatment using paired t-test.

RESULTS

The 6MWD improved by 73 m, from a mean of 435 m (standard deviation [SD] = 92, standard error [SE] = 35) to 508 m (SD = 93, SE = 35) (P = .03). MRI resting aortic flow increased from 3.3 L/minute (SD = 1.27, SE = 0.73) to 4.4 L/minute (SD = 0.9, SE = 0.54) (P = .03). New York Heart Association class was unchanged in three patients, improved in three patients and worsened in one patient. Brain natriuretic peptide, aspartate aminotransferase, and alanine aminotransferase did not change significantly. Of the three patients with elevated baseline bilirubin, two normalized at the completion of the study, while the other was unchanged. Mean duration of therapy was 4.1 ± 0.51 months. Three adverse advents occurred. One patient complained of fatigue and chest pain after 87 days and withdrew from the study. After extensive workup, it was determined that her symptoms were not related to treatment. The second patient suffered palpitations and fatigue after 75 days; no concerning arrhythmias were identified and symptoms improved with increased antiarrhythmic dose. The third patient developed fatigue on therapy and decided to stop therapy; fatigue improved following drug discontinuation. There were no deaths or hospitalizations.

CONCLUSIONS

In this cohort of adult patients with Fontan physiology, endothelin blockade with bosentan resulted in improved 6MWD and MRI-derived resting cardiac output, suggesting a positive effect on pulmonary vascular resistance and pulmonary blood flow. Bosentan was well tolerated and hepatic function was not adversely affected.

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 the majority of 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. Although treatment of the underlying disease and reversal of advanced structural changes has not yet been achieved with current therapy, quality of life and survival have been improved significantly. Targeted pulmonary vasodilator therapies, including endothelin receptor antagonists, prostacyclin analogs, and phosphodiesterase type 5 inhibitors, have demonstrated hemodynamic and functional improvement in children. The management of pediatric PAH remains challenging, as treatment decisions continue to 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.

Current challenges in pediatric pulmonary hypertension

Pulmonary arterial hypertension (PAH) in the pediatric population is associated with a variety of underlying diseases and causes, significantly morbidity and mortality. In the majority of patients, PAH in children is idiopathic or associated with congenital heart disease (CHD), with pulmonary hypertension (PH) associated with connective tissue disease, a rare cause in children. Classification of pediatric PH has generally followed the WHO classification, but recognition of the importance of fetal origins of PH and developmental abnormalities have led to the formation of a new pediatric-specific classification. Incidence data from the Netherlands has revealed an annual incidence and point prevalence of 0.7 and 4.4 for idiopathic PAH and 2.2 and 15.6 for associated pulmonary arterial hypertension-CHD cases per million children. Although the treatment with new selective pulmonary vasodilators offers hemodynamic and functional improvement in pediatric populations, the treatments in children largely depend on results from evidence-based adult studies and experience of clinicians treating children. A recent randomized clinical trial of sildenafil and its long-term extension has led to disparate recommendations in the United States and Europe.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

Advances in diagnosis and treatment of pulmonary arterial hypertension in neonates and children with congenital heart disease

BACKGROUND

This article aims to review recent advances in the diagnosis and treatment of pulmonary arterial hypertension in neonates and children with congenital heart disease.

DATA SOURCES

Articles on pulmonary arterial hypertension in congenital heart disease were retrieved from PubMed and MEDLINE published after 1958.

RESULTS

A diagnosis of primary (or idiopathic) pulmonary arterial hypertension is made when no known risk factor is identified. Pulmonary arterial hypertension associated with congenital heart disease constitutes a heterogenous group of conditions and has been characterized by congenital systemic-to-pulmonary shunts. Despite the similarities in histologic appearance of pulmonary vascular disease, there are differences between pulmonary arterial hypertension secondary to congenital systemic-to-pulmonary shunts and those with other conditions with respect to pathophysiology, therapeutic strategies, and prognosis. Revision and subclassification within the category of secondary pulmonary arterial hypertension based on pathophysiology were conducted to improve specific treatments. The timing of surgical repair is crucial to prevent and minimize risk of postoperative pulmonary arterial hypertension. Drug therapies including prostacyclin, endothelin-receptor antagonist, phosphodiesterase inhibitor, and nitric oxide have been evolved with promising results in neonates and children.

CONCLUSIONS

Among the different forms of congenital heart diseases, an early correction generally prevents subsequent development of pulmonary arterial hypertension. Emerging therapies for treatment of patients with idiopathic pulmonary arterial hypertension also improve quality of life and survival in neonates and children with congenital heart disease associated with pulmonary arterial hypertension. Heart and lung transplantation or lung transplantation in combination with repair of the underlying cardiac defect is a therapeutic option in a minority of patients. Partial repair options are also beneficial in some selected cases. Randomized controlled trials are needed to evaluate the safety and efficacy of these therapies including survival and long-term outcome.