title: [Comparative study of Toronto SPV prosthesis and bileaflet mechanical aortic prosthesis with 2D-Doppler echocardiography].
abstract: OBJECTIVE
  The aim of this study was to make a noninvasive comparison, by means of Doppler echocardiography, of the hemodynamic performance of biological stentless xenografts and mechanical bileaflet (MB) prostheses (P) in aortic position.
  
  
  METHODS
  We studied 20 patients (pts) with normofunctional (nf) aortic Toronto (T) Stentless Porcine valves (SPV)--Group I--8 males, aged 69 +/- 12 years, 32 +/- 9 months after surgery, and 30 pts with nf MB aortic P (Carbomedics or St. Jude Medical)--Group II--17 males (p = NS vs G I), aged 61 +/- 12 years (p < 0.01 vs G I), 30 +/- 12 months after implantation (p = NS vs G I). Both groups were comparable with regard to body surface area and surgical indication. P diameters ranged from 21 to 25 mm (G I: 22.9 +/- 1.7; G II: 22.8 +/- 1.7 - p = NS), the number of pts with the same P diameter in each group being similar. We analysed, at rest: aortic orifice diameter (AoOd - cm), maximal (GMax) and mean (GMean) transprosthesic pressure gradients, P functional area (PFA) and P resistance (PRes). Gradients (mm Hg) were calculated by means of the Bernoulli equation, PFA (cm2) by means of the continuity equation and PRes (dynes.s.cm-5) as 1333 x Gmean x SEP/SV (SEP = systolic ejection period; SV = stroke volume).
  
  
  RESULTS
  AoOd (G I vs G II): P 21--1.78 +/- 0.04 vs 2.00 +/- 0.10 (p < 0.001); P 23--1.91 +/- 0.10 vs 2.19 +/- 0.10 (p = 0.01); P 25--2.22 +/- 0.24 vs 2.29 +/- 0.19 (NS). Doppler parameters: [table: see text]
  
  
  CONCLUSIONS
  P T SPV show better hemodynamic performance when compared to P MB with the same diameter, in aortic position. In addition, our results suggest that P T SPV allow the use of larger valve sizes for the same aortic orifice diameter.
authors.affiliation: Serviço de Cardiologia, Hospital de Santa Marta, Lisboa.
authors.forename: S
authors.initials: S
authors.lastname: Martins
authors.forename: F
authors.initials: F
authors.lastname: Neves
authors.forename: R M
authors.initials: RM
authors.lastname: Soares
authors.forename: D
authors.initials: D
authors.lastname: Cacela
authors.forename: L
authors.initials: L
authors.lastname: do Rosário
authors.forename: P
authors.initials: P
authors.lastname: Coelho
authors.forename: J
authors.initials: J
authors.lastname: Mendes
authors.forename: F
authors.initials: F
authors.lastname: Robalo
authors.forename: N
authors.initials: N
authors.lastname: Castelão
authors.forename: A M
authors.initials: AM
authors.lastname: Antunes
authors.forename: J
authors.initials: J
authors.lastname: Roquette
mesh_terms: D000368:Aged; D001021:Aortic Valve; D001705:Bioprosthesis; D015150:Echocardiography, Doppler; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D011474:Prosthesis Design