title: Durability and prevalence of aortic regurgitation nine years after aortic valve replacement with the Toronto SPV stentless bioprosthesis.
abstract: OBJECTIVE
  Stentless aortic bioprostheses have excellent hemodynamics. Previous investigations of the Toronto SPV valve described a correlation between the occurrence of significant aortic regurgitation (AR) and dilation of the sinotubular junction. The study aim was to determine the long-term durability and determinants of AR at nine years in a large, multicenter study of the Toronto SPV valve.
  
  
  METHODS
  The study included 447 patients from six centers. Clinical outcomes and echocardiographic data (gradients, effective orifice area index (EOA-I), left ventricular mass, aortic root dimensions, and presence and severity of AR) were collected prospectively. A multivariable logistic regression model was used to evaluate clinical and echocardiographic variables for impact on the occurrence of AR.
  
  
  RESULTS
  Total follow up was 2,660 patient-years (mean 6.0 +/- 2.5 years; range: 0 to 11.1 years). Mean gradient and EOA-I remained unchanged through nine years. There were 17 cases of structural deterioration, of which 15 underwent explantation. The mechanism of failure was predominantly leaflet tear in the setting of sinotubular dilation. Freedom from explant for structural failure was 90.1% at nine years (100% for patients aged > or = 65 years). Freedom from hemodynamically significant AR was 96.9% at five years and 82.5% at nine years. Determinants of AR were longer duration of follow up, larger valve size, and increase in the ratio of sinotubular junction to the size of valve implanted.
  
  
  CONCLUSIONS
  At nine years after implantation of the Toronto SPV valve, hemodynamics remained excellent. There was good freedom from structural deterioration through nine years, and structural failure occurred due to aortic root dilation and leaflet tear, without significant valve calcification. AR tends to occur with longer follow up, larger valve sizes, and dilation of the sinotubular junction.
authors.affiliation: Department of Medicine, Division of Cardiology, University of Michigan, Ann Arbor, MI, USA. dbach@umich.edu
authors.forename: David S
authors.initials: DS
authors.lastname: Bach
authors.forename: Bernard
authors.initials: B
authors.lastname: Goldman
authors.forename: Edward
authors.initials: E
authors.lastname: Verrier
authors.forename: Michael
authors.initials: M
authors.lastname: Petracek
authors.forename: Jeremy
authors.initials: J
authors.lastname: Wood
authors.forename: Scott
authors.initials: S
authors.lastname: Goldman
authors.forename: Tirone E
authors.initials: TE
authors.lastname: David
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001022:Aortic Valve Insufficiency / Q000453:epidemiology* / Q000209:etiology; D001705:Bioprosthesis; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011474:Prosthesis Design; D015607:Stents; D013997:Time Factors