Midterm results of balloon dilation of congenital aortic stenosis: Predictors of success

Objectives. We evaluated patient and procedural characteristics that influence the midterm success of balloon dilation of congenital aortic stenosis. Background. Balloon dilation is a new treatment for congenital aortic stenosis. Factors that influence midterm success are unknown. Methods. We performed a retrospective review of 148 children >1 month old who underwent balloon dilation for aortic stenosis. Results. Balloon dilation was successful in 87% of patients, with a procedural mortality rate of 0.7%, The average immediate peak to peak gradient reduction was 56.4 +/- 19.9% (mean +/- SD). Prior valvotomy was the only factor that significantly reduced the immediate gradient reduction after dilation (47.1 +/- 21.8% vs. 57.8 +/- 19.6%, p < 0.01). Survival after dilation was 95% at 8 years. Seventy-five percent of patients were free of repeat intervention 4 years after dilation, whereas 50% remained free of repeat intervention at 8 years. Asymmetrically thick valve leaflets (risk ratio [RR] 0.17, p < 0.01) and prior aortic valvotomy (RR 0.35, p = 0.02) decreased the risk of repeat intervention. Aortic regurgitation grade greater than or equal to 3 (RR 4.27, p = 0.04) and residual gradient after dilation (RR 1.63 for 10 mm Hg, p < 0.01) increased the risk. Conclusions. The 8 year survival rate after dilation was 95%, with 50% of patients free of repeat intervention. Factors that increased the risk for repeat intervention included symmetrically thin or thick aortic valve leaflets, regurgitation grade greater than or equal to 3 after dilation and a high residual gradient after dilation. The incidence of repeat intervention after dilation was high owing to its palliative nature.