Long-Term Outcome of Patients With Isolated Thin Discrete Subaortic Stenosis Treated by Balloon Dilation A 25-Year Study

Background-Transluminal balloon tearing of the membrane in a thin discrete subaortic stenosis is an alternative to membrane surgical resection. However, the long-term outcome of patients with isolated thin discrete subaortic stenosis treated by transluminal balloon tearing remains unknown. Methods and Results-This 25-year study describes findings from 76 patients with isolated thin discrete subaortic stenosis who underwent percutaneous transluminal balloon tearing of the membrane and were followed up for a mean period of 16 +/- 6 years. The age at presentation had a wide range (2-67 years). The mean age at treatment was 19 +/- 16 years. Immediately after treatment, the subvalvular gradient decreased from 70 +/- 27 to 18 +/- 12 mm Hg (P < 0.001). No significant postprocedural aortic regurgitation was observed. After a mean follow-up time of 16 +/- 6 years, 11 patients (15%) developed restenosis, 3 patients (4%) progressed to muscular obstructive disease, and 1 patient (1.3%) developed a new distant obstructive membrane. Twelve patients (16%) were redilated at a mean of 5 +/- 3 years after their first treatment, and 4 patients (5%) underwent surgery at a mean of 3 +/- 2 years after their first treatment. Fifty-eight patients (77%) remained alive and free of redilation or surgery at follow-up. Larger annulus diameter and thinner membranes were independent factors associated with better long-term results. Conclusions-Most patients (77%) with isolated thin discrete subaortic stenosis treated with transluminal balloon tearing of the membrane had sustained relief at subsequent follow-ups without restenosis, the need for surgery, progression to muscular obstructive disease, or an increase in the degree of aortic regurgitation. (Circulation. 2011; 124: 1461-1468.)