A Geometric Model of the Normal Human Aortic Root and Design of a Fully Anatomic Aortic Root Graft

Abstract

Objective

Available aortic root grafts generally flare outward in the sinus region, and this feature improves procedural ease. However, no current device is based on normal aortic root geometry, and a fully anatomic aortic root graft could further facilitate valve-sparing root operations.

Methods

To develop a model of the normal human aortic root, high-resolution computed tomographic angiogram images from 11 normal human aortas generated high-density x, y, z coordinates of valve and root structures in Mathematica. Three-dimensional least-squares regression analyses assessed geometry of the aortic valve and root. Shapes and dimensions were quantified, and minor variations in geometry were simplified during graft design.

Results

Normal aortic valve and root geometry was represented as three leaflet-sinus general ellipsoids nested within a cylindrical aorta. Sinotubular junction diameter was 5 mm larger than the valve base—with a slight funnel-shaped outward commissural flare but cylindrical geometry above the midvalve. The valve base was elliptical, but the midvalve and the sinotubular junction were circular above the midvalve level. Commissural locations on the base circumference were equidistant. On the basis of average three-dimensional geometry, a root graft was designed for root remodeling procedures—to be used with an internal geometric annuloplasty ring of the same design.

Conclusions

An aortic root graft was designed on the basis of mathematical analyses of computed tomographic angiogram images. The design incorporated three anatomic sinuses, commissural symmetry, and compatibility with geometric ring annuloplasty. The anatomic graft may prove useful for restoring aortic root geometry toward normal during aortic valve and root surgery.