title: Initial experience with the Toronto Root bioprosthesis.
abstract: OBJECTIVE
  The study aim was to assess the safety and efficacy of the Toronto Root bioprosthesis for aortic root or valve replacement during the early postoperative stages.
  
  
  METHODS
  Between November 2000 and December 2002, the Toronto Root was implanted in 191 patients in 17 institutions. The patients' mean age was 65 years (range: 25 to 87 years) and 70% were males. The bioprosthesis was implanted as a full aortic root in 76% of patients, as a root inclusion in 9%, and in the subcoronary position in 15%. The sizes used in decreasing frequency were 27, 29, 25, 23 and 21 mm. Coronary artery bypass was performed in 25% of patients. Echocardiography was performed before hospital discharge and at six months postoperatively. Serum aluminum levels were monitored pre- and postoperatively as this metal is used in anticalcification treatment of the arterial wall of the porcine root. For the purpose of this study, follow up was closed at six months in all patients, and was complete.
  
  
  RESULTS
  Eight patients died, though none of the deaths was valve-related. Two patients required reoperation because of technical errors during implantation. Two patients developed endocarditis, one patient required surgical intervention, and two patients suffered cerebral transient ischemic attacks. All survivors experienced symptomatic improvement, and 97% were in NYHA functional classes I and II at six months postoperatively. Blood levels of aluminum were unchanged at follow up. The mean effective orifice area of all valves studied was 2.0 +/- 0.8 cm2, and the mean systolic gradient 7.0 +/- 3.9 mmHg at six months postoperatively. No patient had more than trace aortic insufficiency.
  
  
  CONCLUSIONS
  Early experience with the Toronto Root bioprosthesis has shown it to be a safe and effective valve for aortic valve or aortic root replacement, with excellent hemodynamic characteristics, a low transvalvular gradient and a large effective orifice area.
authors.affiliation: Cardiac Surgical Programs, Toronto General Hospital, Toronto, ON, Canada. tirone.david@uhn.on.ca
authors.forename: Tirone E
authors.initials: TE
authors.lastname: David
authors.forename: Friedrich W
authors.initials: FW
authors.lastname: Mohr
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Bavaria
authors.forename: John W
authors.initials: JW
authors.lastname: Hammon
authors.forename: Marvin J
authors.initials: MJ
authors.lastname: Smith
authors.forename: Reed D
authors.initials: RD
authors.lastname: Quinn
authors.forename: David S
authors.initials: DS
authors.lastname: Bach
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery; D001705:Bioprosthesis; D004452:Echocardiography; D004869:Equipment Safety; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009656:North America; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality; D011474:Prosthesis Design; D016019:Survival Analysis; D016896:Treatment Outcome