Left Ventricular Vortex Under Mitral Valve Edge-to-Edge Repair.
Left Ventricular Vortex Under Mitral Valve Edge-to-Edge Repair.
复制标题
二尖瓣下左心室涡边缘对边缘修复。
DOI：
10.1007/s13239-010-0022-6
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发表时间：
2010
影响因子：
1.8
通讯作者：
He,Zhaoming
中科院分区：
文献类型：
--
作者：
Hu,Yingying;Shi,Liang;Parameswaran,Siva;Smirnov,Sergey;He,Zhaoming
二尖瓣（MV）缘对缘修复（ETER）通过对合MV瓣叶改变MV几何形状，并影响左心室（LV）充盈流体力学。本研究的目的是使用MV ETER研究舒张期左室涡流。在前瓣叶和后瓣叶的中央自由边缘处使用MV ETER开发了计算MV-LV模型。一般认为左心室在舒张期会向心尖延长。伸长变形受脑室内流速控制。MV瓣叶被建模为具有两个对称圆孔的半长球形，并固定在最大瓣膜开口处。MV腱索被忽略。使用FLUENT模拟通过MV和LV的血流。MV ETER在快速LV充盈中产生两个侧向偏转至LV壁的射流。射流斜向撞击左室壁，并沿左室壁向顶沿着移动。射流能量主要损失在冲击附近。来自每个MV孔口的射流被涡环包围。两个漩涡环在漩涡的尽头消散。总能量损失与二尖瓣口面积成反比。房室压差在接近舒张末期时为逆压，可能在舒张末期。总瓣口面积的减少导致了更多的增量，在跨瓣压降比跨瓣速度。总而言之，在ETER下的二尖瓣在扩张过程中，有两股偏转射流撞击左心室壁。主要的能量损失发生在射流冲击附近。两个涡环在舒张末期消散，在随后的收缩过程中，几乎没有储存用于血液喷射的流入能量。MV ETER增加了能量损失，降低了LV充盈效率。ETER后维持较大的瓣口面积可能不会显著增加二尖瓣关闭不全期间LV的能量损失和二尖瓣压力下降。从心房到左心室的逆压梯度可能是二尖瓣关闭的机制。
Mitral valve (MV) edge-to-edge repair (ETER) changes MV geometry by approximation of MV leaflets, and impacts left ventricle (LV) filling fluid mechanics. The purpose of this study was to investigate LV vortex with MV ETER during diastole. A computational MV–LV model was developed with MV ETER at the central free edges of the anterior and posterior leaflets. It was supposed that LV would elongate apically during diastole. The elongation deformation was controlled by the intraventricular flow rate. MV leaflets were modeled as a semi-prolate sphere with two symmetrical circular orifices and fixed at the maximum valve opening. MV chordae were neglected. FLUENT was used to simulate blood flow through the MV and in the LV. MV ETER generated two jets deflected laterally toward the LV wall in rapid LV filling. The jets impinged the LV wall obliquely and moved apically along the LV wall. Jet energy was primarily lost near the impingement. The jet from each MV orifice was surrounded by a vortex ring. The two vortex rings dissipated at the end of diastole. The total energy loss increased inversely with the MV orifice area. The atrio-ventricular pressure gradient was adverse near the end of diastole and possibly in diastasis. Reduction of the total orifice area led to more increment in the transmitral pressure drop than in the transmitral velocity. In conclusion, during diastole, two deflected jets from the MV under ETER impinged the LV wall. Major energy loss occurred around the jet impingement. Two vortex rings dissipated at the end of diastole with little storage of inflow energy for blood ejection in the following process of systole. MV ETER increased energy loss and lowered LV filling efficiency. The maintaining of a larger orifice area after ETER might not significantly increase energy loss in the LV during diastole and the transmitral pressure drop. The adverse pressure gradient from the atrium to the LV might be the mechanism of MV closure in the late diastole.