title: A randomized comparison of the MCRI On-X and CarboMedics Top Hat bileaflet mechanical replacement aortic valves: early postoperative hemodynamic function and clinical events.
abstract: OBJECTIVE
  This study compared hemodynamic function and clinical events in consecutive patients randomly assigned to receive a wholly supra-annular replacement valve or a valve with an intra-annular component.
  
  
  METHODS
  Fifty-two patients with an average age of 62 years (range 40-74 years) were sized for both a CarboMedics Top Hat valve (CarboMedics Inc, Austin, Tex) and an MCRI On-X valve (Medical Carbon Research Institute, LLC, Austin, Tex) before random assignment to receive either valve type. Echocardiographic and clinical assessments were performed in the immediate postoperative period and at 1 year.
  
  
  RESULTS
  The mean effective orifice areas were 1.41 +/- 0.42 cm2 for the Top Hat and 2.17 +/- 0.78 cm2 for the On-X (P < .0001). The mean pressure differences were 12.2 +/- 4.4 mm Hg and 6.9 +/- 3.6 mm Hg, respectively (P < .0001). New York Heart Association functional class was better with the On-X than the Top Hat valves, but there were no differences in clinical events, regression of left ventricular mass, or measures of hemolysis.
  
  
  CONCLUSIONS
  The partially intra-annular MCRI On-X valve was hemodynamically superior to the wholly supra-annular CarboMedics Top Hat valve. However, there were no differences in early clinical outcomes between the two valve types.
authors.affiliation: Valve Study Group, Guy's and St Thomas Hospitals, London, United Kingdom. jboydchambers@aol.com
authors.forename: J
authors.initials: J
authors.lastname: Chambers
authors.forename: J
authors.initials: J
authors.lastname: Roxburgh
authors.forename: C
authors.initials: C
authors.lastname: Blauth
authors.forename: J
authors.initials: J
authors.lastname: O'Riordan
authors.forename: F
authors.initials: F
authors.lastname: Hodson
authors.forename: H
authors.initials: H
authors.lastname: Rimington
mesh_terms: D000328:Adult; D000368:Aged; D001021:Aortic Valve / Q000601:surgery*; D001022:Aortic Valve Insufficiency / Q000503:physiopathology / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000503:physiopathology / Q000601:surgery; D008078:Cholesterol, LDL / Q000097:blood; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011474:Prosthesis Design
chemical_list: D008078:Cholesterol, LDL