title: Design characteristics of a three-dimensional geometric aortic valve annuloplasty ring.
abstract: OBJECTIVE
  A full geometric annuloplasty ring could facilitate aortic valve repair. The purpose of this report was to document the design of such a ring using mathematical analyses of normal human aortic valve computed tomographic angiograms.
  
  
  METHODS
  One-millimeter axial slices of high-resolution computed tomographic angiograms from 11 normal aortic roots were used to generate high-density x, y, and z coordinates of valve structures in Mathematica. Three-dimensional least squares regression analyses of leaflet-sinus coordinates were used to assess geometry of aortic valve and root structures.
  
  
  RESULTS
  Normal valve geometry could be represented as three leaflet-sinus general ellipsoids nested within an elliptical aortic root. Minor-major diameter ratio of the valve base was 0.60 ± 0.07, and elliptical geometry extended vertically up the commissures. By contrast, leaflet-sinus horizontal circumferences were fairly circular (diameter ratios, 0.82-0.87), and the left coronary/noncoronary commissural post was located at the posterior base minor diameter-circumference junction, with the center of the right coronary leaflet opposite. Post location on the circumference was symmetrical, with a deviation of only ±2% to ±3% from 33.3% symmetry. Commissural posts flared outward by 5 to 10 degrees, and leaflet areas were statistically equivalent (P > 0.10). From end diastole to midsystole, the aortic root became less elliptical (diameter ratio increased by 0.15), but root area expanded minimally (less than +5%). A one-piece rigid annuloplasty ring was designed with 2:3 base ellipticality, three 10-degree outwardly flaring symmetrical posts, and post height = base circumference/2π.
  
  
  CONCLUSIONS
  A three-dimensional aortic annuloplasty ring was designed that could prove useful for enhancing applicability and stability of aortic valve repair.
authors.affiliation: From the *Department of Mathematics, Vanderbilt University, Nashville, TN USA; †BioStable Science and Engineering, Inc, Austin, TX USA; ‡German Heart Center Munich, Munich, Germany; and §Department of Cardiac Surgery, Vanderbilt University, Nashville, TN USA.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Crooke
authors.forename: L Alan
authors.initials: LA
authors.lastname: Beavan
authors.forename: Charles D
authors.initials: CD
authors.lastname: Griffin
authors.forename: Domenico
authors.initials: D
authors.lastname: Mazzitelli
authors.forename: J Scott
authors.initials: JS
authors.lastname: Rankin
mesh_terms: D001021:Aortic Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D058385:Cardiac Valve Annuloplasty / Q000295:instrumentation*; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D011474:Prosthesis Design / Q000379:methods* / Q000592:standards; D014057:Tomography, X-Ray Computed