title: Impact of small valve size on hemodynamics and left ventricular mass regression with the Toronto SPV stentless aortic bioprosthesis.
abstract: OBJECTIVE
  The hemodynamic performance of stentless aortic bioprostheses has been previously well described. Because the potential for prosthesis-patient mismatch is greatest for small valves in the aortic position, the present study sought to compare the hemodynamic performance and degree of left ventricular (LV) mass regression between valve sizes for the Toronto SPV valve, with special interest in measures of relief of LV outflow obstruction afforded by the smallest valves.
  
  
  METHODS
  This study included 257 patients (178 men, 79 women; mean age 63.5+/-11.4 years; range: 34-93 years) from six investigative centers with complete echocardiography/Doppler data obtained through three years. Valve sizes implanted were 21 mm (n = 11), 23 mm (n = 23), 25 mm (n = 58), 27 mm (n = 83), and 29 mm (n = 82). Echocardiography was performed at discharge, six months, one year, and yearly thereafter, and interpreted in a centralized core laboratory. Mean gradient, effective orifice area (EOA), indexed EOA, and absolute and percent change in LV mass index were used as markers of hemodynamic performance.
  
  
  RESULTS
  For all valve sizes, mean and peak gradients fell and EOA increased early after surgery. There were no differences between groups in the degree to which gradients fell, and EOA increased from discharge to one year follow up. At one year, indexed EOA was 0.9 cm2/m2 for valve sizes 21 and 23 mm, and 1.0-1.2 cm2/m2 for sizes 25, 27 and 29 mm. There was statistically significant LV mass regression for all valve sizes (p <0.05), and no differences between valve sizes in the magnitude of absolute or percent change in LV mass index between baseline and three years.
  
  
  CONCLUSIONS
  The Toronto SPV valve demonstrates excellent parameters of hemodynamic performance for all valve sizes, including the smallest valves used in only a minority of patients. Findings of indexed EOA > or = 0.9 cm2/m2, and equivalent degrees of LV mass regression for all valve sizes, reinforces the excellent hemodynamic performance of stentless aortic bioprostheses, and suggests that prosthesis-patient mismatch should be minimized with these valves.
authors: Department of Medicine, University of Michigan, Ann Arbor 48109, USA.
authors: David S
authors: DS
authors: Bach
authors: Bernard
authors: B
authors: Goldman
authors: Edward
authors: E
authors: Verrier
authors: Michael
authors: M
authors: Petracek
authors: Jeremy
authors: J
authors: Wood
authors: Scott
authors: S
authors: Goldman
authors: Tirone
authors: T
authors: David
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000503:physiopathology* / Q000601:surgery*; D001705:Bioprosthesis; D002170:Canada; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000503:physiopathology* / Q000601:surgery*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge; D015607:Stents; D013997:Time Factors; D014481:United States