Balloon mitral valvuloplasty (BMV) is an effective intervention in patients with symptomatic mitral stenosis. However, the late results of BMV in children and adolescents have not been well studied. The aim of this study was to assess the late functional and morphologic results after BMV in children and adolescents. BMV was performed in 46 children and adolescents (mean age 15.5 +/- 3.2 years, range 7 to 19; 19 males) with rheumatic mitral stenosis. Serial clinical and echocardiographic evaluation was conducted to assess the long-term results of the procedure during a follow-up period of 66 +/- 6 months. The mitral valve score was 6 +/- 2/16. BMV was successful in 45 patients (98%). There was a significant increase of the mean mitral valve area index (MVAI) (0.65 +/- 0.14 vs 1.54 +/- 0.23 cm2/m2, p <0.001) and a significant reduction of the mean transmitral pressure gradient (16.1 +/- 2.9 vs 5.1 +/- 3.1 mm Hg, p <0.001) from pre- to post-BMV, respectively. There was no significant change of MVAI or the pressure gradient during the follow-up compared with immediately after BMV (1.51 +/- 0.31 cm2/m2 and 4.9 +/- 2.5 mm Hg, respectively). No deaths or mitral valve replacement occurred during the follow-up period. Restenosis (loss of >50% of the achieved increase in MVAI) occurred in 3 patients (6.5%). All other patients showed persistent improvement in their New York Heart Association class (< or = II). Thus, the event-free survival with good functional results was encountered in 42 patients (91%) at the end of the follow-up period. The left atrial diameter decreased from 4.6 +/- 0.9 before BMV to 3.7 +/- 0.6 cm at follow-up (p <0.05). It is concluded that BMV has excellent intermediate-term results in children and adolescents with a relatively low mitral valve score.