title: Risk factors for reoperation after relief of congenital subaortic stenosis.
abstract: BACKGROUND
  Congenital subaortic stenosis entails a lesion spectrum, ranging from an isolated obstructive membrane, to complex tunnel narrowing of the left outflow associated with other cardiac defects. We review our experience with this anomaly, and analyze risk factors leading to restenosis requiring reoperation.
  
  
  METHODS
  From 1994 to 2006, 58 children (median age 4.3 years, range 7 days-13.7 years) underwent primary relief of subaortic stenosis. Patients were divided into simple lesions (n=43) or complex stenosis (n=15) associated with other major cardiac defects. Age, pre- and postoperative gradient over the left outflow, associated aortic or mitral valve insufficiency, chromosomal anomalies, arteria lusoria, and operative technique (membrane resection (22) vs associated myectomy (34) vs Konno (2)) were analyzed as risk factors for reoperation (Kaplan-Meier, Cox regression).
  
  
  RESULTS
  There was no operative mortality. Median follow-up spanned 2.7 years (range 0.1-10), with one late death at 4 months. Reoperation was required for recurrent stenosis in 11 patients (19%) at 2.6 years (range 0.3-7.5) after initial surgery. Risk factors for reoperation included complex subaortic stenosis (p=0.003), younger age (p=0.012), postoperative residual gradient (p=0.019), and the presence of an arteria lusoria (p=0.014). For simple lesions, no variable achieved significance for stenosis recurrence.
  
  
  CONCLUSIONS
  Surgical relief of congenital subaortic stenosis, even with complex defects, yields excellent results. Reoperation is not infrequent, and should be anticipated with younger age at operation, complex defects, residual postoperative gradient, and an arteria lusoria. Myectomy concomitant to membrane resection, even in simple lesions, does not provide enhanced freedom from reoperation, and should be tailored to anatomic findings.
authors.affiliation: Division of Congenital Cardiovascular Surgery, University Children's Hospital, University of Zurich, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland. ali.dodge-khatami@kispi.uzh.ch
authors.forename: Ali
authors.initials: A
authors.lastname: Dodge-Khatami
authors.forename: Michael
authors.initials: M
authors.lastname: Schmid
authors.forename: Valentin
authors.initials: V
authors.lastname: Rousson
authors.forename: Margrit
authors.initials: M
authors.lastname: Fasnacht
authors.forename: Carsten
authors.initials: C
authors.lastname: Doell
authors.forename: Urs
authors.initials: U
authors.lastname: Bauersfeld
authors.forename: René
authors.initials: R
authors.lastname: Prêtre
mesh_terms: D000293:Adolescent; D001020:Aortic Stenosis, Subvalvular / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D001021:Aortic Valve / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053208:Kaplan-Meier Estimate; D016016:Proportional Hazards Models; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D016896:Treatment Outcome; D016277:Ventricular Function, Left