Interventional Cardiology 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.)