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.
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.
Accepted for publication July 21, 2013.
Supported by BioStable Science and Engineering, Austin, TX USA.
Presented at the Annual Scientific Meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, June 12–15, 2013, Prague, Czech Republic.
Disclosures: Philip S. Crooke, PhD, and Domenico Mazzitelli, MD, are consultants; L. Alan Beavan, MSE, and Charles D. Griffin, MSE, are officers; and J. Scott Rankin, MD, is chief medical officer for BioStable Science and Engineering, Inc, Austin, TX USA.
Address correspondence and reprint requests to J. Scott Rankin, MD, 320 Lynnwood Blvd, Nashville, TN 37205 USA. E-mail: firstname.lastname@example.org.