title: Outcomes after the Norwood operation in neonates with critical aortic stenosis or aortic valve atresia.
abstract: OBJECTIVE
  This study was undertaken to determine the demographic, anatomic, institutional, and surgical risk factors associated with outcomes after the Norwood operation.
  
  
  METHODS
  A total of 710 of 985 neonates with critical aortic stenosis or atresia enrolled in a prospective 29-institution study between 1994 and 2000 underwent the Norwood operation. Admission echocardiograms were independently reviewed for 64% of neonates. Competing risks analyses were constructed for outcomes after Norwood operation and after cavopulmonary shunt. Incremental risk factors for outcome events were sought.
  
  
  RESULTS
  Overall survivals after the Norwood operation were 72%, 60%, and 54% at 1 month, 1 year, and 5 years, respectively. According to competing risks analysis, 97% of neonates reached a subsequent transition state by 18 months after Norwood operation, consisting of death (37%), cavopulmonary shunt (58%), or other state (2%, cardiac transplantation, biventricular repair, or Fontan operation). Risk factors for death occurring before subsequent transition included patient-specific variables (lower birth weight, smaller ascending aorta, older age at Norwood operation), institutional variables (institutions enrolling < or =10 neonates, two institutions enrolling >/=40 neonates), and procedural variables (shunt originating from aorta, longer circulatory arrest time, and management of the ascending aorta). Of neonates undergoing cavopulmonary shunt, 91% had reached a subsequent transition state by 6 years after cavopulmonary shunt, consisting of Fontan operation (79%), death (9%), or cardiac transplantation (3%). Risk factors for death occurring before subsequent transition included younger age at cavopulmonary shunt and need for right atrioventricular valve repair.
  
  
  CONCLUSIONS
  Competing risks analysis defines the prevalence of the various outcomes after Norwood operation and predicts improved outcomes with successful modification of controllable risk factors.
authors.affiliation: Division of Cardiovascular Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Ashburn
authors.forename: Brian W
authors.initials: BW
authors.lastname: McCrindle
authors.forename: Christo I
authors.initials: CI
authors.lastname: Tchervenkov
authors.forename: Marshall L
authors.initials: ML
authors.lastname: Jacobs
authors.forename: Gary K
authors.initials: GK
authors.lastname: Lofland
authors.forename: Edward L
authors.initials: EL
authors.lastname: Bove
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Spray
authors.forename: William G
authors.initials: WG
authors.lastname: Williams
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Blackstone
mesh_terms: D001011:Aorta / Q000002:abnormalities* / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000150:complications / Q000401:mortality / Q000601:surgery*; D006348:Cardiac Surgical Procedures / Q000379:methods* / Q000401:mortality; D006801:Humans; D007231:Infant, Newborn; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome; D014694:Ventricular Outflow Obstruction / Q000209:etiology / Q000401:mortality / Q000601:surgery*