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 new treatment for congenital aortic stenosis. Factors that influence midterm success are unknown. Methods. We performed 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 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 ≥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 ≥3 after dilation and high residual gradient after dilation. The incidence of repeat intervention after dilation was high owing to its palliative nature.