title: The modified Konno procedure for complex left ventricular outflow tract obstruction.
abstract: BACKGROUND
  Complex left ventricular outflow tract (LVOT) obstruction with normal aortic valve function requires aggressive resection in the subaortic region and preservation of the aortic valve. The modified Konno procedure allows generous exposure of the LVOT from the left ventricular apex to the inter leaflet trigones of the aortic valve. Widespread use of this procedure has been limited by concern over injury to the aortic valve, the conduction system, and possibility of residual ventricular septal defect (VSD).
  
  
  METHODS
  Retrospective analysis of pertinent data for all patients undergoing the modified Konno procedure (1994 to 2001) at the University of Iowa were reviewed.
  
  
  RESULTS
  The modified Konno procedure was used in 18 patients (age 1 to 31) for LVOT obstruction associated with diffuse narrowing of the LVOT (n = 7), a discrete fibrous ring (n = 7), or a fibrous ring associated with abnormal mitral attachments (n = 4). Eight patients had previously undergone LVOT resection. There were no perioperative deaths. Estimated LVOT peak gradients by echocardiogram were 70.4 +/- 24.2 mm Hg (preoperative) and 19.2 +/- 20.4 mm Hg (postoperative) at most recent followup (p < 0.001 vs preop). Aortic insufficiency was moderate in one patient (present preop) and mild or less in all other patients. There were no cases of permanent heart block. Small residual VSDs were present in five patients (28%). Median follow-up is 3.1 years.
  
  
  CONCLUSIONS
  The modified Konno procedure can effectively relieve complex LVOT obstruction and preserve aortic valve function. Extension of this procedure for use in the initial presentation of LVOT may be appropriate in cases at increased risk of recurrent LVOT obstruction.
authors.affiliation: Division of Cardiothoracic Surgery, Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242, USA. chris-caldarone@uiowa.edu
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Caldarone
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Van Natta
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Frazer
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Behrendt
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008722:Methods; D011183:Postoperative Complications; D012189:Retrospective Studies; D014694:Ventricular Outflow Obstruction / Q000601:surgery*