title: Stentless aortic valves are hemodynamically superior to stented valves during mid-term follow-up: a large retrospective study.
abstract: BACKGROUND
  Several studies have compared left venticular mass (LVM) regression and hemodynamic data for stentless versus stented aortic bioprostheses with conflicting results. The major limitations of these studies are their small sample size and short-term follow-up. We therefore compared midterm LVM regression, hemodynamic data, and survival in a large population of tissue aortic valve replacement (AVR) patients.
  
  
  METHODS
  All patients undergoing tissue AVR at our institution between 1998 and 2001 were included (n = 737). Patients were divided into two groups according to type of bioprosthetic implanted: stentless patients (total n = 310) (Toronto SPV [St Jude Medical, St Paul, MN], n = 146 and Freestyle [Medtronic, Minneapolis, MN], n = 164) and stented patients (total n = 427) (Perimount [Edwards Life Sciences Inc, Irvine, CA], n = 291 and Mosaic [Medtronic], n = 136).
  
  
  RESULTS
  The two groups of patients had similar preoperative transvalvular gradients and LVM index (130 +/- 47 vs 130 +/- 42 g/m2 for stentless versus stented valves, respectively). Predischarge echos revealed that stentless patients had significantly lower mean transvalvular gradients (11 +/- 5 vs 15 +/- 6 mm Hg, p < 0.001) and larger effective orifice areas (1.32 +/- 0.52 vs 1.22 +/- 0.48 cm2, p = 0.01). Follow-up echocardiograms were obtained in 99% of surviving patients 28 +/- 22 (range, 0-79) months postoperatively. Stentless patients had significantly lower LVM index during follow-up (100 +/- 32 vs 107 +/- 32 g/m2, p = 0.005) and stentless valves were an independent predictor of LVM regression. Furthermore, a higher proportion of stented patients had residual LV hypertrophy during follow-up (28% vs 18%, p = 0.001). Stentless valves were associated with improved midterm survival by univariate analysis, but not by multivariable analysis.
  
  
  CONCLUSIONS
  Midterm follow-up in a large number of patients reveals that stentless bioprostheses are hemodynamically superior to stented valves.
authors.affiliation: Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada. michael.borger@uhn.on.ca
authors.forename: Michael A
authors.initials: MA
authors.lastname: Borger
authors.forename: Susan M
authors.initials: SM
authors.lastname: Carson
authors.forename: Joan
authors.initials: J
authors.lastname: Ivanov
authors.forename: Vivek
authors.initials: V
authors.lastname: Rao
authors.forename: Hugh E
authors.initials: HE
authors.lastname: Scully
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Feindel
authors.forename: Tirone E
authors.initials: TE
authors.lastname: David
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000502:physiology* / Q000601:surgery*; D001705:Bioprosthesis; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis; D006439:Hemodynamics; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000601:surgery; D008297:Male; D012189:Retrospective Studies; D015607:Stents; D013997:Time Factors