为了探讨窦管交界和窦部直径对主动脉瓣关闭功能的影响,首先按照Labrosse提供的临床手术指导尺寸,建立基本的主动脉根部几何模型;改变窦管交界直径(分别为基本模型的1.2倍和0.8倍)、窦部直径(分别为基本模型的1.2倍和0.8倍)以及窦管交界直径和窦部直径(均为基本模型的1.2倍),共建立6组几何模型.窦部和瓣叶均施加0~10.665 kPa线性变化的压力负载,用计算机数值模拟的方法定量研究主动脉根部从接近关闭到完全关闭过程中,模型受到的最大应力数值和位置、瓣环直径变化以及对合区域面积比.计算结果表明:6组模型的主动脉根部最大应力值均出现在瓣叶和窦部接合位置,且最大应力值的范围是567~601 kPa,与Marom、Labrosse和Katayama的计算结果接近;窦管交界直径增大为基本模型的1.2倍时,瓣环直径扩大8.3%;6组模型的对合区域面积比计算结果相对变化不超过5%.结果表明:窦管交界变化比窦部直径变化对瓣环直径的影响大,而同样的主动脉根部结构,增大瓣环直径会减少瓣叶的有效对合,从而影响主动脉瓣关闭功能.
The aim of present study was to determine the effects of diameters of sinotubular junction and maximum sinus on aortic valve closure function. The 3-dimensional geometry of a base aortic valve was reconstructed using the geometric constraints and modeling dimensions suggested by Labrosse,and then the diameters of sinotubular junction and maximum sinus were modified to create six geometric models with different dimensions. The models were simulated in a controlled situation which focused on the closing diastolic phase of the valve,starting with an almost closed valve. The pressure was raped from 0up to 10. 665 kPa. The performance of the aortic root was quantified in terms of value and position of maximum stress,annulus diameter as well as normalized ratio of cusp coaptation area. Results show that the maximum stress values occur at the connection between valve leaflets and sinuses for all models.Annulus diameter was increased 8. 3% with sinotubular junction diameter increased 1. 2 times. Relative changes of normalized cusp coaptation area were less than 5% for all six models. Compared with the maximum sinus diameter,sinotubular junction diameter has far more influence on annulus diameter,namely,on the function of aortic valve,because increasing the annulus diameter decreases the leaflet effective coaptation for the same aortic root.
Journal of Beijing Polytechnic University
sinotubular junction diameter
maximum sinus diameter
normalized cusp coaptation area