title: A randomized comparison of the Cryolife O'Brien and Toronto stentless replacement aortic valves.
abstract: OBJECTIVE
  A composite stentless valve might be less obstructive than a preparation incorporating the porcine right coronary muscle bar. The aim of this study was to compare early hemodynamic function in a prospective series of 78 patients randomized to receive either a Toronto or Cryolife O'Brien stentless valve.
  
  
  METHODS
  Echocardiography was performed early after surgery, between 3 and 6 months, and at 1 year after surgery.
  
  
  RESULTS
  The groups were matched demographically. The Cryolife O'Brien valve was significantly less obstructive in terms of effective orifice area (1.81 vs 1.30 cm2; P < .0001), mean pressure difference (7.1 vs 11.7 mm Hg; P < .0001), and peak velocity (1.7 vs 2.2 m/s) assessed at 1 year (P = .001). Bypass time was 91 (SD 22) minutes for the Cryolife O'Brien compared with 125 (SD 22) minutes (P < .0001) for the Toronto. There was a higher incidence of paraprosthetic regurgitation in the Cryolife O'Brien valve (16.7% vs 3.2%). Mortality and clinical events were similar.
  
  
  CONCLUSIONS
  The composite valve was less obstructive than the porcine valve, suggesting that stentless valves cannot be considered as a homogeneous class.
authors: The Valve Study Group, St Thomas Hospital, London, UK. jboydchambers@aol.com
authors: John B
authors: JB
authors: Chambers
authors: Helen M
authors: HM
authors: Rimington
authors: Ronak
authors: R
authors: Rajani
authors: Fiona
authors: F
authors: Hodson
authors: Fikrat
authors: F
authors: Shabbo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve; D001705:Bioprosthesis; D005260:Female; D006349:Heart Valve Diseases / Q000209:etiology / Q000601:surgery*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies