Objective: To evaluate treatment outcomes of pediatric valvar aortic stenosis (AS) in a nationwide follow-up.Design: Balloon aortic valvuloplasty (BAV) has been the preferred treatment for congenital AS in Finland since the year 2000. All children treated due to isolated AS during 2000-2014 were included in this retrospective study. Treatment outcomes were categorized into Optimal: residual gradient ≤35 mmHg and trivial or no aortic regurgitation (AR), Adequate: gradient ≤35 mmHg with mild AR, or Inadequate: gradient >35 mmHg and/or moderate to severe AR.Results: Sixty-one patients underwent either BAV (n = 54) or surgical valvuloplasty (n = 7) for valvar AS at a median age of 29 days (range 6 hours to 16.9 years). The proportion of patients not requiring reintervention at 1, 5, and 10 years was 61%, 50%, and 29% in neonates and 83%, 73%, and 44% in older patients, respectively (p = .02); without difference between treatment groups. Larger proportion of patients remained free from valve surgery after optimal BAV result than after adequate or inadequate result (p = .01). The reason for the first reintervention was AS in 50%, AR in 36%, and combined aortic valve disease in 16% of cases. Early mortality (before hospital discharge) was 4.9%, and associated with critical AS in neonates. There was no late mortality during the follow-up.Conclusions: Although majority of congenital AS patients require more than one intervention during childhood, an optimal BAV result improves long-term outcome by increasing the proportion of patients remaining free from valve surgery. High long-term freedom from reintervention is attainable also in the neonatal population. [ABSTRACT FROM AUTHOR]