Surgical treatment of subvalvular aortic stenosis. Long-term results.

From 1966 till May 1988, 53 patients underwent surgery for fixed subaortic stenosis. Subvalvular obstruction was isolated in 27 patients (Group I) and associated with aortic valve lesions in 26 (Group II). A membranous stricture was documented in 5 patients and a fibromuscular ring in 48. Excision of the ring and myectomy were performed in all patients, and an associated aortic valve replacement or reconstruction in 7 and 4 patients respectively. There were no hospital deaths. Follow-up evaluation in 50 patients ranged from 6 months to 22 years. Eight patients had to be reoperated upon (1 from group I, 7 from group II): aorto-ventriculoplasty was performed in 3, aortic valve replacement with redo myectomy in 3 and mitro-aortic valve replacement in 2. One of them had 2 reoperations. Functional status at the time of the last outpatient visit was most satisfactory. Continued evaluation remains necessary as obstruction may reappear despite the absence of symptoms.