Balloon mitral valvulotomy in children aged < or = 12 years

Balloon mitral valvulotomy (BMV) was studied in children aged < or = 12 years to study its efficacy, to assess the effects of age and body surface area on outcome, and to determine whether the definition of mitral stenosis and recommendations for balloon size used in adults are applicable to very young patients. At present, data on BMV or guidelines for balloon size in small children are not available.

Clinical, echocardiographic and hemodynamic data were obtained from 13 patients before and after BMV. At follow up, correlation coefficients were identified for clinical, echocardiographic or procedural variables with increase in the degree of mitral regurgitation (MR), age and body surface area.

BMV was successful in 12 patients (93%), with increased valve area and cardiac index and decreased left atrial and pulmonary artery pressure gradients. Moderate MR developed in two patients (15%), but did not correlate with any variable. Symptom improvement was seen at follow up. Seven patients (54%) experienced adverse events: restenosis occurred in five cases (38%), and symptom recurrence and valve replacement for endocarditis occurred in one patient (8%). Kaplan-Meier analysis showed that by 20 months after BMV, 60% of patients had experienced an event. The percentage fall in pulmonary artery pressure correlated with body surface area, but not age.

BMV is effective in very small children, but a high incidence of moderate MR occurs, mainly because the choice of balloon size is made using an adult-style, height-based nomogram and a stepwise increase in balloon size during BMV. Correct nomograms to define mitral stenosis, restenosis and balloon size must be developed for small children.