Paediatric Pulmonary hypertension (PH) is a diverse diseases which occur at any age and it’s usually progressive. There are differences in aetiology, presentation and outcomes in children, therefore require a unique approach as compared to adults.
Historically, paediatric PH is defined as mean pulmonary arterial pressure (mPAP) ⩾25 mmHg after 3 months of age. The 6th WSPH proposed new definition for PH as mPAP >20 mmHg and to include PVR ⩾3 WU·m2 measured during cardiac catherization to identify pre-capillary PH. The definition of PH when using echocardiography is when systolic PA pressure is more than half systolic systemic pressure.
There are many classifications for PH according to the aetiology. Generally PH is classified into pulmonary arterial hypertension (PAH), PH due to left heart disease, PH due to lung disease and/or hypoxia, PH due to pulmonary artery obstruction and PH due to unclear and/or multifactorial mechanisms.
The presentation of paediatric PH are nonspecific, and clinical features may be subtle even in advanced disease. Neonates and infants may present with hydrops fetalis, right ventricular dysfunction, loud pulmonary second sound and heart failure. In bigger children, the symptoms are breathlessness, reduced effort tolerance, fatiguability, chest pain, seizures, arryhthmias, syncope, hemoptysis and symptoms contributing to systemic diseases. Symptomatic severity based on functional capacity has been connected to prognosis.
The diagnosis is still mainly based on echocardiographic and cardiac catheter findings (gold standard). A thorough diagnostic workup is important as the treatment options depend upon the underlying cause which may be treatable. Respiratory system investigations includes chest radiograph, arterial blood gas and pulmonary function tests. Sleep studies should be undertaken to identify obstructive sleep apnoea (OSAS). A ventilation perfusion scan could be useful in particular in chronic thromboembolic phenomenon. More definitive tests include pulmonary angiogram and/or high resolution CT scan and cardiac MRI. A 6 minute walk test and/or cardiopulmonary exercise testing are used to evaluate exercise capacity. Biomarkers such as BNP and ProBNP is also helpful. Genetic studies should be considered if one suspects inheritable conditions.
Treating PH involves multidisciplinary care and often challenging as mainly rely on evidence-based adult studies and the paediatric experts’ opinion. PH that is caused by upper airway obstruction might undergo adenotonsillectomy, and those with chronic respiratory disorders should be managed with the relevant therapeutics, including home oxygen and non-invasive ventilation (NIV). Sympathomimetic decongestants with α-adrenergic that cause vasoconstriction should be avoided. Children with PAH may benefit from treatment with PAH-targeted drugs: prostanoids/prostacyclin (epoprostenol, treprostinil, iloprost, beraprost), ERAs (bosentan, ambrisentan), and PDE5 inhibitors (sildenafil, tadalafil) as well as calcium channel antagonist, either alone or combination therapy. However, the role of PAH pharmacotherapy in patients whose primary abnormality is lung disease remains speculative. A trial of PAH-targeted therapy is reasonable in patients with advanced lung disease with evidence of PAH as PH/PAH confers a significant increase in morbidity and mortality.