Crooke Philip S, Beavan L Alan, Griffin Charles D, Mazzitelli Domenico, Rankin J Scott
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.
Innovations (Phila). 2015 Jan-Feb;10(1):57-62. doi: 10.1097/IMI.0000000000000125.
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.
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.
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.
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.
现有的主动脉根部移植物通常在窦部向外扩张，这一特性提高了手术的便利性。然而，目前尚无基于正常主动脉根部几何形状的装置，而完全解剖学的主动脉根部移植物可能会进一步促进保留瓣膜的根部手术。
为了建立正常人体主动脉根部模型，利用来自11例正常人体主动脉的高分辨率计算机断层血管造影图像，在Mathematica中生成瓣膜和根部结构的高密度x、y、z坐标。三维最小二乘回归分析评估主动脉瓣和根部的几何形状。对形状和尺寸进行量化，并在移植物设计过程中简化几何形状的微小变化。
正常主动脉瓣和根部的几何形状表现为三个小叶 - 窦部的一般椭球体嵌套在圆柱形主动脉内。窦管交界处直径比瓣膜基部大5mm，有轻微的漏斗形向外连合部扩张，但在瓣膜中部上方为圆柱形几何形状。瓣膜基部为椭圆形，但在瓣膜中部上方，瓣膜中部和窦管交界处为圆形。基部圆周上的连合位置等距。基于平均三维几何形状，设计了一种用于根部重塑手术的根部移植物，可与相同设计的内部几何瓣环成形环一起使用。
基于计算机断层血管造影图像的数学分析设计了一种主动脉根部移植物。该设计纳入了三个解剖学窦部、连合对称性以及与几何瓣环成形术的兼容性。这种解剖学移植物可能在主动脉瓣和根部手术中有助于将主动脉根部几何形状恢复至正常。
