Biomechanical implications of the congenital bicuspid aortic valve: A finite element study of aortic root function from in vivo data
Biomechanical implications of the congenital bicuspid aortic valve: A finite element study of aortic root function from in vivo data
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DOI：
10.1016/j.jtcvs.2010.01.016
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发表时间：
2010-10-01
影响因子：
6
通讯作者：
Redaelli, Alberto
中科院分区：
文献类型：
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作者：
Conti, Carlo A.;Della Corte, Alessandro;Redaelli, Alberto
目的：先天性二尖瓣主动脉瓣经常引起主动脉瓣狭窄或反流。为了实现外科修复技术的进步，需要提高对瓣膜和根部生物力学的理解。通过使用成像数据，开发了有限元模型来量化与二尖瓣几何形状相关的主动脉瓣和根部生物力学改变。方法：开发了具有二尖瓣主动脉瓣（1 型右/左）的主动脉根部的动态 3 维有限元模型。该模型的几何结构基于对 8 名血压正常且健康的受试者采集的二维磁共振图像的测量结果，这些受试者的二尖瓣主动脉瓣超声心动图功能正常。将数值结果与我们之前代表具有三尖瓣主动脉瓣的正常根部的模型获得的结果进行比较。还评估了中缝增厚对瓣膜运动学和应力的影响。结果：在收缩期，二尖瓣与正常瓣膜相比打开不对称，导致其孔口呈椭圆形。在舒张期，联合尖瓣闭塞了较大比例的瓣膜孔口，并且小叶弯曲发生了改变，但能力得以保留。与三尖瓣模型相比，二尖瓣模型呈现出更高的应力，特别是在联合牙尖的中央基底区域（+800%）。中缝的存在部分减少了该区域的应力，但增加了其他尖点的应力。结论：在临床上功能正常的二叶式主动脉瓣中，主动脉瓣功能发生了改变。二尖瓣几何形状本身就导致了异常的小叶应力。应力位置表明小叶应力可能在中缝区域的组织重塑和早期小叶退化中发挥作用。 （《胸心血管外科杂志》2010 年；140：890-6）
Objective: Congenital bicuspid aortic valves frequently cause aortic stenosis or regurgitation. Improved understanding of valve and root biomechanics is needed to achieve advancements in surgical repair techniques. By using imaging-derived data, finite element models were developed to quantify aortic valve and root biomechanical alterations associated with bicuspid geometry.Methods: A dynamic 3-dimensional finite element model of the aortic root with a bicuspid aortic valve (type 1 right/left) was developed. The model's geometry was based on measurements from 2-dimensional magnetic resonance images acquired in 8 normotensive and otherwise healthy subjects with echocardiographically normal function of their bicuspid aortic valves. Numeric results were compared with those obtained from our previous model representing the normal root with a tricuspid aortic valve. The effects of raphe thickening on valve kinematics and stresses were also evaluated.Results: During systole, the bicuspid valve opened asymmetrically compared with the normal valve, resulting in an elliptic shape of its orifice. During diastole, the conjoint cusp occluded a larger proportion of the valve orifice and leaflet bending was altered, although competence was preserved. The bicuspid model presented higher stresses compared with the tricuspid model, particularly in the central basal region of the conjoint cusp (+800%). The presence of a raphe partially reduced stress in this region but increased stress in the other cusp.Conclusions: Aortic valve function is altered in clinically normally functioning bicuspid aortic valves. Bicuspid geometry per se entails abnormal leaflet stress. The stress location suggests that leaflet stress may play a role in tissue remodeling at the raphe region and in early leaflet degeneration. (J Thorac Cardiovasc Surg 2010; 140: 890-6)