title: The initial experience with the ATS Medical mechanical cardiac valve prosthesis.
abstract: BACKGROUND
  From May 1994 through October 2000, a total of 1,146 patients underwent valve replacement with the ATS Medical mechanical cardiac valve prosthesis under a study protocol approved by international ethics committees (non-United States participants) or under a United States Food and Drug Administration-approved Investigational Device Exemption study. The study took place at 19 domestic and three international centers.
  
  
  METHODS
  As required by the Food and Drug Administration's Heart Valve Guidance Document, only isolated implants were included in the study (double-valve implants were excluded), with operative and follow-up data collected from each center.
  
  
  RESULTS
  Aortic valve replacement (AVR) was conducted in 801 patients (309 with coronary bypass) and mitral valve replacement (MVR) in 345 patients (78 with coronary bypass). Overall operative (< or = 30 days post implant) mortality was 2.1% (17 AVR = 2.1%, 7 MVR = 2.0%), 7 of which (AVR = 4, MVR = 3) were valve related. In 2,086 patient-years (1,459 AVR patient-years, 627 MVR patient-years) of follow-up, there were an additional 50 patient deaths of these, 18 were valve related, 9 due to anticoagulant related bleeding, 5 sudden/unexplained, and 1 each after stroke, thrombosis, prosthetic valve endocarditis, and thromboembolism. Late (>30 days post implant) valve-related complications included: transient and chronic thromboembolism (27 AVR (linearized rate 1.85%/patient-year) and 20 MVR (3.19%/patient-year), of which 11/47 (0.53%/patient-year) had chronic deficits, thrombosis (1 AVR = 0.07%/patient-year and 4 MVR = 0.64%/patient-year), paravalvular leak (10 AVR = 0.69%/patient-year and 8 MVR = 1.28%/patient-year), anticoagulant related hemorrhage (34 AVR = 2.33%/patient-year and 8 MVR = 1.28%/patient-year), prosthetic valve endocarditis (3 AVR = 0.21%/patient-year and 2 MVR = 0.32%/patient-year), and structural valve failure or dysfunction (0%). Echocardiographic gradients were proportional to valve size and did not significantly change over the follow-up period.
  
  
  CONCLUSIONS
  This study documented the ATS Medical mechanical cardiac valve prosthesis to be a valuable addition to the surgeon's armamentarium in the treatment of cardiac valvular disease.
authors.affiliation: Cardiac Surgical Associates, Minneapolis, Minnesota, USA. remery@csa-heart.com
authors.forename: Robert W
authors.initials: RW
authors.lastname: Emery
authors.forename: Guido J
authors.initials: GJ
authors.lastname: Van Nooten
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Tesar
mesh_terms: D000368:Aged; D001021:Aortic Valve; D015897:Comorbidity; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000453:epidemiology / Q000601:surgery; D005260:Female; D006349:Heart Valve Diseases / Q000453:epidemiology / Q000401:mortality / Q000601:surgery; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve; D011446:Prospective Studies; D011474:Prosthesis Design