Vasodilator therapy for pulmonary hypertension in children: a national study of patient characteristics and current treatment strategies.

Pulmonary vasodilator therapy is still often an off-label treatment for pulmonary hypertension in children. The aim of this nationwide register-based study was to assess patient characteristics and strategies for pulmonary vasodilator therapy in young Swedish children. Prescription information for all children below seven years of age at treatment initiation, between 2007 and 2017, was retrieved from the National Prescribed Drug Register, and medical information was obtained by linkage to other registers. All patients were categorized according to the WHO classification of pulmonary hypertension. In total, 233 patients had been prescribed pulmonary vasodilators. The treatment was initiated before one year of age in 61% (N = 143). Sildenafil was most common (N = 224 patients), followed by bosentan (N = 29), iloprost (N = 14), macitentan (N = 4), treprostinil (N = 2) and riociguat (N = 2). Over the study period, the prescription rate for sildenafil tripled. Monotherapy was most common, 87% (N = 203), while 13% (N = 20) had combination therapy. Bronchopulmonary dysplasia (N = 82, 35%) and/or congenital heart defects (N = 156, 67%) were the most common associated conditions. Eight percent (N = 18) of the patients had Down syndrome. Cardiac catheterization had been performed in 39% (N = 91). Overall mortality was 13% (N = 30) during the study period. This study provides an unbiased overview of national outpatient use of pulmonary vasodilator therapy in young children. Few cases of idiopathic pulmonary arterial hypertension were found, but a large proportion of pulmonary hypertension associated with congenital heart defects or bronchopulmonary dysplasia. Despite treatment, mortality was high, and additional pediatric studies are needed for a better understanding of underlying pathologies and evidence of treatment effects.