[Percutaneous intraluminal balloon dilatation of valvular pulmonary stenoses in infancy and childhood. Presentation of results with special reference to balloon size].

34 percutaneous balloon valvuloplasties (BVP), including four repeat procedures, were performed in 30 patients (aged 3 months to 19.4 years, mean 5.8 years) with congenital pulmonary valve stenosis. Out of six failures four were due to dysplastic thickened valves; in two children a significant part of obstruction was on the subvalvular level. After first BVP a significant reduction of the right ventricular outflow tract (RVOT) gradient (mean 58.8 +/- 13.2%) was achieved in 24 of 30 cases. The mean pre-BVP RVOT gradient of 67 +/- 24.4 mm Hg was reduced to 27.2 +/- 10.2 mm Hg. Of 24 patients, 14 had a residual RVOT gradient of 25 mm Hg or less. Of the 24 patients, nine were recatheterized 12 to 24 months later, and a further RVOT gradient reduction (33.4 +/- 9.9 mm Hg to 24.2 +/- 14.5 mm Hg) was observed. In four patients additional RVOT gradient reduction (37.3 +/- 11.6 mm Hg to 18.5 +/- 10.5 mm Hg) was achieved by repeat BVP. Balloon size exceeded valve annulus diameter by up to 58% (mean 22%). No definite correlation between balloon size related to pulmonary valve annulus diameter and magnitude of right ventricular systolic pressure reduction was observed. Even using a maximal balloon size of 158%, no significant complications were noted, not even pulmonary valve insufficiency.