Etiology, diagnosis, and pharmacologic treatment of pediatric pulmonary hypertension

Migraine signaling pathways: amino acid metabolites that regulate migraine and predispose migraineurs to headache

Migraine is a common, debilitating disorder for which attacks typically result in a throbbing, pulsating headache. Although much is known about migraine, its complexity renders understanding the complete etiology currently out of reach. However, two important facts are clear, the brain and the metabolism of the migraineur differ from that of the non-migraineur. This review centers on the altered amino acid metabolism in migraineurs and how it helps define the pathology of migraine.

CHD and respiratory syncytial virus: global expert exchange recommendations

BACKGROUND

Palivizumab is the standard immunoprophylaxis against serious disease due to respiratory syncytial virus infection. Current evidence-based prophylaxis guidelines may not address certain children with CHD within specific high-risk groups or clinical/management settings.

METHODS

An international steering committee of clinicians with expertise in paediatric heart disease identified key questions concerning palivizumab administration; in collaboration with an additional international expert faculty, evidence-based recommendations were formulated using a quasi-Delphi consensus methodology.

RESULTS

Palivizumab prophylaxis was recommended for children with the following conditions: <2 years with unoperated haemodynamically significant CHD, who are cyanotic, who have pulmonary hypertension, or symptomatic airway abnormalities; <1 year with cardiomyopathies requiring treatment; in the 1st year of life with surgically operated CHD with haemodynamically significant residual problems or aged 1-2 years up to 6 months postoperatively; and on heart transplant waiting lists or in their 1st year after heart transplant. Unanimous consensus was not reached for use of immunoprophylaxis in children with asymptomatic CHD and other co-morbid factors such as arrhythmias, Down syndrome, or immunodeficiency, or during a nosocomial outbreak. Challenges to effective immunoprophylaxis included the following: multidisciplinary variations in identifying candidates with CHD and prophylaxis compliance; limited awareness of severe disease risks/burden; and limited knowledge of respiratory syncytial virus seasonal patterns in subtropical/tropical regions.

CONCLUSION

Evidence-based immunoprophylaxis recommendations were formulated for subgroups of children with CHD, but more data are needed to guide use in tropical/subtropical countries and in children with certain co-morbidities.

Sildenafil in Infants and Children

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

Pulmonary hypertension specific treatment in infants with bronchopulmonary dysplasia

OBJECTIVE

When bronchopulmonary dysplasia (BPD) is complicated by pulmonary hypertension (PH), morbidity and mortality are significantly increased. BPD-associated PH is not included in the current indications for PH medications. However, limited data demonstrate hemodynamic improvement and decreased mortality with PH-specific treatment. This report describes our 6-year experience treating BPD-associated PH with PH medications, mainly sildenafil.

STUDY DESIGN

The medical records of 20 infants diagnosed with BPD-associated PH at a tertiary pediatric pulmonary hypertension clinic in 2008-2014 were reviewed. Clinical improvement was defined as a decrease in Ross functional class by at least one degree. PH severity was classified by echocardiography as mild, moderate, or severe. Hemodynamic improvement was defined as a decrease in PH severity by at least one level.

RESULTS

Eighteen out of 20 patients were treated with PH medications: 12 sildenafil, 5 sildenafil and bosentan, and 1 bosentan. Median follow-up time was 2 years. Mean functional class significantly decreased from 3.2 ± 0.9 at diagnosis to 1.7 ± 0.9 at the last follow-up. Improvement in functional class was observed in 15/16 children (94%). Moderate or severe PH was found in 13/18 children (72%) at diagnosis, and in three (17%, all moderate PH) at the last follow-up. Improvement in PH class by echocardiography was demonstrated in 14/18 children (78%). The survival rate was 95%.

CONCLUSION

Treatment of BPD complicated by PH with PH-specific medications, mainly sildenafil, is associated with improvement in both clinical and hemodynamic parameters and a low mortality rate. Pediatr Pulmonol. 2017;52:77-83. © 2016 Wiley Periodicals, Inc.

Paediatric pulmonary hypertension and sildenafil: current practice and controversies

In recent times, paediatric pulmonary arterial hypertension management has been transformed to focus on disease modifying strategies that improve both quality of life and survival, rather than just symptom palliation. Sildenafil, a phosphodiesterase-V inhibitor, has been at the centre of this. Despite controversial beginnings, its success in treating pulmonary arterial hypertension has led to its consideration for related pathologies such as persistent pulmonary hypertension of the newborn and bronchopulmonary dysplasia, as well as the development of a range of alternative formulations. However, this has caused its own controversy and confusion regarding the use of sildenafil in younger patients. In addition, recent data regarding long-term mortality and the repeal of US drugs approval have complicated the issue. Despite such setbacks, sildenafil continues to be a major component of the contemporary care of paediatric pulmonary hypertension in a variety of contexts, and this does not seem likely to change in the foreseeable future.

Systemic endothelial dysfunction in children with idiopathic pulmonary arterial hypertension correlates with disease severity

BACKGROUND

Idiopathic pulmonary arterial hypertension (IPAH) is a life-threatening disease manifested by progressive pulmonary vascular remodeling, compromised pulmonary blood flow and right heart failure. Most studies have explored how pulmonary endothelial function modulates disease pathogenesis. We hypothesize that IPAH is a progressive panvasculopathy, affecting both pulmonary and systemic vascular beds, and that systemic endothelial dysfunction correlates with disease severity. Recent studies have demonstrated systemic endothelial dysfunction in adults with pulmonary hypertension; however, adults often have additional comorbidities affecting endothelial function. Systemic endothelial function has not been explored in children with IPAH.

METHODS

In this single-center, prospective, cross-sectional study we examined brachial artery flow-mediated dilation (FMD), a nitric oxide-mediated, endothelial-dependent response, in children with IPAH and matched controls. FMD measurements were compared with clinical and echocardiographic measures of IPAH severity.

RESULTS

Thirteen patients and 13 controls were studied, ranging in age from 6 to 20 years. FMD was decreased in IPAH subjects compared with controls (5.1 ± 2.1% vs 9.7 ± 2.0%; p < 0.0001). In IPAH subjects, FMD correlated directly with cardiac index (R(2) = 0.34, p = 0.035), and inversely with tricuspid regurgitation velocity (R(2) = 0.57, p = 0.019) and right ventricular myocardial performance index (R(2) = 0.44, p = 0.028).

CONCLUSIONS

The presence of systemic endothelial dysfunction in children with IPAH and its strong association with IPAH severity demonstrate that IPAH is a global vasculopathy. Although morbidity in IPAH is typically associated with pulmonary vascular disease, systemic vascular changes may also relate to disease pathogenesis and progression. Further study into shared mechanisms of systemic and pulmonary endothelial dysfunction may contribute to future therapies for IPAH.

Management of pulmonary hypertension in Down syndrome

Children with Down syndrome (DS) are at greater risk of pulmonary arterial hypertension (PAH) than the general population, partly due to upper airway obstruction and congenital heart disease. We wished to review our management of PAH and suggest a protocol for the systematic management of these children. Children with DS and PAH were included as referred for assessment from March 2005 to May 2010. Twenty-five patients (13 boys) met inclusion criteria. The median age was 385 days (range, 106 to 5,734); mean tricuspid regurgitation jet was 3.5 (range, 2.7-4.8) m/s. At cardiac catheterisation, mean pulmonary artery mean pressure was 26 mmHg (range, 12 to 46), and mean pulmonary vascular resistance (PVR) was 4.14 U.m² (range, 1.20 to 12.43) at baseline. PVR fell to a mean of 2.68 U.m² (range, 0.38 to 10.69) with 20 ppm inhaled nitric oxide and 100% oxygen. Respiratory assessment included polysomnography (18), bronchoscopy (16), showing malacia (eight), adenotonsillar hypertrophy (eight) and floppy aryepiglottic folds (four). One lung biopsy showed plexogenic arteriopathy, and one was diagnosed with tracheo-oesophageal fistula.

CONCLUSION

In order to manage this complex group of patients, a combined cardiological, respiratory and surgical approach was required. A protocol with cardiac catheterisation, blood tests and respiratory assessment is suggested for the management of pulmonary hypertension in these children.