title: In-vitro comparison of aortic valve hemodynamics between aortic root remodeling and aortic valve reimplantation.
abstract: OBJECTIVE
  Valve-preserving aortic replacement has become an accepted option for patients with aortic valve regurgitation and aortic dilatation. The relative role of root remodeling versus valve reimplantation inside a vascular graft has been discussed, albeit controversially. In the present study, an in-vitro model was used to investigate the aortic valve hemodynamics of root remodeling and valve reimplantation; roots with supracommissural aortic replacement served as controls.
  
  
  METHODS
  Aortic roots with aortoventricular diameter 21 mm were obtained from pigs. Root remodeling was performed using a 22-mm graft (group I, n = 6), or valve reimplantation with a 24-mm graft (group II, n = 7). Control roots were treated by supracommissural aortic replacement (22-mm graft; group III, n = 7). Using an electrohydraulic, computer-controlled pulse duplicator, the valves were tested at flows of 2, 4, 5, 7, and 9 I/min at a heart rate of 70 /min and a mean arterial pressure of 100 mmHg. Parameters assessed included: mean pressure gradient, effective orifice area, valve closure and regurgitant volume, and energy loss due to ejection, valve closure and regurgitation. Data were compared using ANOVA.
  
  
  RESULTS
  There were no differences between the three groups in terms of regurgitant volume, energy loss due to valve regurgitation, or valve closure. The aortic valve orifice area was largest and systolic gradient lowest in group I at all flow rates (p < 0.001). Ejection energy loss was lowest in group I at all flow rates (9 l/min: group I, 128 +/- 21 mJ; group II, 399 +/- 46 mJ; group III, 312 +/- 27 mJ; p < 0.001). Valve closure volumes were similar in groups I and III, but significantly lower in group II at all flow rates (p = 0.047).
  
  
  CONCLUSIONS
  In this standardized experimental setting, root remodeling--but not valve reimplantation--resulted in physiologic hemodynamic performance of the aortic valve with regard to orifice area, pressure gradient, and systolic energy loss.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital Homburg, Homburg/Saar, Germany.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Graeter
authors.forename: Roland
authors.initials: R
authors.lastname: Fries
authors.forename: Diana
authors.initials: D
authors.lastname: Aicher
authors.forename: Helmut
authors.initials: H
authors.lastname: Reul
authors.forename: Christoph
authors.initials: C
authors.lastname: Schmitz
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Schäfers
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology*; D001021:Aortic Valve / Q000502:physiology*; D004734:Energy Metabolism; D019918:Heart Valve Prosthesis Implantation; D006439:Hemodynamics / Q000502:physiology*; D023421:Models, Animal; D012086:Reoperation; D013552:Swine; D020257:Ventricular Remodeling