title: Mobilization of the left and right fibrous trigones for relief of severe left ventricular outflow obstruction.
abstract: BACKGROUND
  There is still no agreement about the optimal method of surgical relief of fixed subaortic stenosis, particularly the severe forms.
  
  
  OBJECTIVE
  The purpose of this study was to describe a new technique for the relief of subaortic stenosis based on analysis of the functional anatomy of the left ventricular outflow tract and pathophysiologic features of subaortic stenosis.
  
  
  METHODS
  We propose that one of the basic abnormalities in subaortic stenosis is interference with the hinge mechanism provided by the 2 fibrous trigones with progressive deposition of fibrous tissue in these angles. The technique described in this paper consists of excision of all components of the fibrous "ring," with mobilization of the left and right fibrous trigones. This results in the restoration of the normal dynamic behavior of the left ventricular outflow tract with maximal widening of the outflow tract as the result of backward displacement of the subaortic curtain and anterior leaflet of the mitral valve. This technique has been used in 57 consecutive patients who ranged in age between 5 months and 56 years (mean, 15.5 +/- 10.6 years). Gradients across the left ventricular outflow tract were between 45 and 200 mm Hg (mean, 86.7 mm Hg). Additional lesions were present in 10 patients, and 7 patients had had 8 previous operations on the left ventricular outflow tract. At operation, in addition to resection of subaortic stenosis, 3 patients had aortic valvotomy, 2 patients had homograft replacement of the aortic valve, 7 patients had patch closure of a ventricular septal defect, and 1 patient had open mitral valvotomy.
  
  
  RESULTS
  There were 2 early deaths and 1 late sudden death during the follow-up period that ranged from 1 month to 25 years (mean, 15. 2 years). One patient experienced the development of endocarditis on the aortic valve 7 years after operation, which was successfully treated by homograft replacement. Postoperative gradients across the left ventricular outflow tract varied from no gradient to 30 mm Hg (mean, 8 mm Hg). There were no instances of recurrence of a gradient across the left ventricular outflow tract.
  
  
  CONCLUSIONS
  It is concluded that mobilization of the left and right fibrous trigones results in durable relief of subaortic stenosis.
authors.affiliation: Department of Cardiothoracic Surgery, Royal Brompton and Harefield Hospital, Imperial College of Science, Medicine and Technology, Heart Science Center, Harefield, Uxbridge, Middlesex, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Yacoub
authors.forename: O
authors.initials: O
authors.lastname: Onuzo
authors.forename: B
authors.initials: B
authors.lastname: Riedel
authors.forename: R
authors.initials: R
authors.lastname: Radley-Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006348:Cardiac Surgical Procedures / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*