title: The Toronto SPV bioprosthesis: clinical and hemodynamic results at 6 years.
abstract: BACKGROUND
  The Toronto SPV (stentless porcine valve) bioprosthesis has been in use for aortic valve replacement since July 1991. Before its approval by the Food and Drug Administration, 635 patients were enrolled in a prospective observational clinical trial in eight centers. This report is an update on that trial.
  
  
  METHODS
  There were 419 men and 216 women whose mean age was 66 years, range 33 to 93 years. In addition to aortic valve replacement, 264 patients also had coronary artery bypass, 9 had mitral valve repair, and 7 had replacement of the ascending aorta. The external diameter of most valves implanted was 25 mm or greater. Echocardiography has been done annually. The follow-up for this report was closed in September 1998 and mean follow-up was 2.7 years, range 0 to 6.3 years.
  
  
  RESULTS
  There were 17 operative and 38 late deaths. Actuarial survival was 82.6% at 6 years. Freedom from morbid events at 6 years was 90% for cardiac-related deaths, 93.6% for all thromboembolic events, 98.6% for endocarditis, 98.2% for repeat aortic valve replacement, and 100% for primary tissue failure. Approximately 85% of patients have no aortic insufficiency, with no change in this proportion during the first 6 years of observation. The mean systolic gradient decreased during the first 6 months and remained unchanged over the years. It was approximately 5 mm Hg for all patients. Most patients (81%) are free from cardiac symptoms.
  
  
  CONCLUSIONS
  This porcine bioprosthetic valve has provided excellent clinical and hemodynamic results after aortic valve replacement. Longer follow-up is needed to determine its durability and the potential benefits of its hemodynamic features.
authors.affiliation: Division of Cardiovascular Surgery, Toronto Hospital and the University of Toronto, Ontario, Canada.
authors.forename: T E
authors.initials: TE
authors.lastname: David
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001705:Bioprosthesis / Q000009:adverse effects; D018572:Disease-Free Survival; D004696:Endocarditis / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000009:adverse effects; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012086:Reoperation; D015996:Survival Rate; D013923:Thromboembolism / Q000209:etiology