HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): William G. Williams Christopher A. Caldarone Glen S. Van Arsdell Brian W. McCrindle Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Karamlou, T. Articles by McCrindle, B. W. Search for Related Content PubMed PubMed Citation Articles by Karamlou, T. Articles by McCrindle, B. W. Related Collections Congenital - acyanotic

Ann Thorac Surg 2007;84:900-906
© 2007 The Society of Thoracic Surgeons

---

Original Articles: Cardiovascular

Prevalence and Associated Risk Factors for Intervention in 313 Children With Subaortic Stenosis

^a Divisions of Cardiovascular Surgery and Cardiology, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
^b Department of Pediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada

Accepted for publication March 20, 2007.

^_* Address correspondence to Dr McCrindle, The Hospital for Sick Children, 555 University Ave, Toronto, Ontario, M5G 1X8, Canada (Email: brian.mccrindle{at}sickkids.ca).

Presented at the Forty-third Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 29–31, 2007.

Background: We sought to determine the prevalence of intervention and associated factors in children presenting with subaortic stenosis. We also investigated whether a protocol adopted in 1994 of early subaortic resection at a preoperative mean systolic gradient across the left ventricular outflow tract (LV gradient) greater than 30 mm Hg was supported by longitudinal outcomes.

Methods: Record review of all children (n = 313) diagnosed with subaortic stenosis was conducted between 1975 and 1998 at our institution. Cox proportional hazard models determined the prevalence and associated factors for initial subaortic resection. Mixed models of serially obtained echocardiographic data (n = 933) established longitudinal LV gradient trends and identified factors associated with more rapid LV gradient progression.

Results: Median age at presentation was 8 months. Freedom from initial subaortic resection was 40% at 16 years from diagnosis. Earlier progression to subaortic resection was associated with patient characteristics at presentation, including a higher initial LV gradient (p < 0.001), larger aortic annulus z-score (p = 0.005), smaller body surface area (p < 0.001), and smaller mitral annulus z-score (p = 0.003). Initial resection was also associated with a faster rate of LV gradient progression (p = 0.003). Factors determining the increased rate of LV gradient progression included an initial LV gradient greater than 30 mm Hg (p < 0.001), initial aortic valve thickening (p = 0.003), and attachment of subaortic stenosis to the mitral valve (p = 0.003). Worse aortic regurgitation grade with time was also associated with an initial LV gradient greater than 30 mm Hg (p < 0.001).

Conclusions: Subaortic resection should be delayed until the LV gradient exceeds 30 mm Hg because most children with an initial LV gradient less than 30 mm Hg have quiescent disease.