title: The Carbomedics Top Hat supraannular aortic valve: a multicenter study.
abstract: BACKGROUND
  Introduced in 1993, the Carbomedics Top Hat (Sulzer, Carbomedics, Austin, TX) valve is a bileaflet mechanical aortic prosthesis designed to be placed in a supraannular position. Five institutions pooled their clinical experiences to evaluate early outcome in patients with this prosthesis.
  
  
  METHODS
  From 1994 to 2000, 639 patients underwent aortic valve replacement with Top Hat (Sulzer Carbomedics) valves at 5 institutions. Mean age was 60 +/- 13 years. In this heterogeneous population, 28% of patients had previous cardiac operations and 64% had concomitant procedures, including procedures involving more than 1 heart valve in 32%. Implanted prostheses sizes included the 19 mm (15%), 21 mm (37%), 23 mm (33%), 25 mm (13%), and 27 mm (2%). Mean follow-up was 2.0 +/- 1.5 years, and there were 1,206 patient-years of follow-up available for analysis.
  
  
  RESULTS
  Thirty-day mortality was 5.3%. Five-year survival was 74%. Risk factors for death included older age (p = 0.01), decreased ejection fraction (p = 0.007), and increased New York Heart Association functional class (p = 0.003). Five-year freedoms from thromboembolism and hemorrhage were 90% and 85%, respectively. Five-year freedoms from explant and endocarditis were both 99%. There were no structural valve failures.
  
  
  CONCLUSIONS
  The Top Hat valve outcomes have been similar to those of the standard Carbomedics intraannular prostheses. The unique design of the Top Hat valve, with all its components in the aortic sinuses, has particular advantages in the small aortic root, in settings where leaflet entrapment may occur, and in multiple valve replacement.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. gillinom@ccf.org
authors.forename: A Marc
authors.initials: AM
authors.lastname: Gillinov
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Blackstone
authors.forename: Joan M
authors.initials: JM
authors.lastname: Alster
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Craver
authors.forename: William A
authors.initials: WA
authors.lastname: Baumgartner
authors.forename: Scot A
authors.initials: SA
authors.lastname: Brewster
authors.forename: Leonard H
authors.initials: LH
authors.lastname: Kleinman
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Smedira
mesh_terms: D001021:Aortic Valve; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011474:Prosthesis Design; D012086:Reoperation; D015996:Survival Rate; D013923:Thromboembolism / Q000209:etiology