Operation for discrete subvalvular aortic stenosis.

Abstract

Over the past 20 years, 37 patients (31 children and six adults) have undergone operations for discrete subvalvular aortic stenosis. Prior to 1975, resection of the subvalvular membrane alone was the procedure of choice. However, the recurrence rate was high (36%). Since 1975, resection of the membrane plus left ventricular myectomy has been routine. The recurrence rate in this group has been lower (20%) but is still high. Overall, 11 patients (30%) have had significant recurrence (average gradient 63 mm Hg). Eight of these 11 have undergone a second operation with re-resection of a membrane and left ventricular myectomy. One patient died and in three others (42%) significant symptoms and gradients remained. One of these three has undergone a successful aortoventriculoplasty, and two patients are awaiting a similar operation. Lessons learned from this experience include the following: (1) Regardless of the type of initial operation, a significant rate of recurrence can be anticipated. (2) Progressive aortic insufficiency and fibromuscular tunnel stenosis occur commonly unless adequate relief of the obstruction is achieved by the first operation. (3) Because repeat resection with left ventricular myectomy is unlikely to be effective when aortic insufficiency and/or tunnel stenosis are present, aortoventriculoplasty should be employed as the definitive reoperative procedure.