Pediatric pulmonary arterial hypertension: characteristics and efficacy of specific therapy on clinical, echocardiographic and hemodynamic parameters

Pulmonary arterial hypertension (PAH) in children has peculiar features and require a unique approach. This study describes the epidemiological features of pediatric PAH patients followed in a referral center and investigates the effects of PAH-targeted drugs. Data from consecutive pediatric PAH patients referred to our center from 1980 to 2024 were collected. Of 137 patients, 60 (44%) had idiopathic/hereditary PAH (I/HPAH) and 60 (44%) had PAH associated with congenital heart disease (PAH-CHD). PAH-CHD patients were slightly younger than I/HPAH at diagnosis and there was not a female predominance. When considering treatment strategy, among IPAH, 14 (23%) patients showed a positive response to acute vasoreactivity test at diagnosis and were treated with calcium-channel blocker, but only 3 (5%) were long-term responders. Excluding acute responders, compared to PAH-CHD, I/H PAH patients were usually treated with a more aggressive strategy. Treatment strategy efficacy was confirmed by a significant improvement in symptoms, in exercise capacity, in echocardiographic parameters and in hemodynamics with a significant increase in cardiac index, in values of pulmonary artery oxygen saturation and reduction in pulmonary vascular resistance index. In conclusion, this series confirms a different distribution of pediatric PAH etiologies compared to adults, with children having a greater predominance of I/HPAH and PAH-CHD. In children with I/HPAH, treatment strategy is similar to adults with rapid sequential or upfront oral combination therapy if lower risk and initial parenteral combination therapy if high risk. In PAH-CHD, treatment strategy is characterized by a more prudential approach with first-line monotherapy and combination therapy in case of inadequate response. Beyond hemodynamics, PAH-targeted drugs’ effects are demonstrated by a significant improvement in symptoms, exercise capacity and right ventricle echocardiographic parameters suggesting a role of this non-invasive and easily available tools in monitoring disease progression and treatment response.