Komoda T, Hetzer R, Oellinger J, Siniawski H, Hofmeister J, Hübler M, Felix R, Uyama C, Maeta H
Department of Cardiovascular Surgery, German Heart Institute Berlin, Germany.
Technol Health Care. 1997 Jul;5(3):207-17.
The mechanism of left ventricular outflow tract (LVOT) obstruction in the patient after mitral valve replacement or repair was examined with the aid of 2D echocardiography. For the interpretation of the spatial relationship between the aortic root and mitral annulus, however, the 2D display is sometimes inadequate since it may not simultaneously capture these structures in each center. We developed a method to clarify this relationship in 3D based on magnetic resonance images. We defined the office of the left ventricular outflow tract (LVOT orifice), consisting of, in turn, a muscular region, i.e., edge of the interventricular septum, and an annular region, i.e., the annulus of the anterior mitral leaflet. In this paper we present image data obtained from one of eight normal subjects examined and compare this with data of one of two patients who preoperatively suffered degenerative mitral regurgitation and subsequently underwent chordal-preserving mitral valve replacement, in which anterior chordae were reattached to the anterior annulus. In the normal subject, the mitral annulus exhibited a flexible change in shape during the systole, maintaining sufficient LVOT orifice size. In the patient, the prosthetic valve exhibited translational motion during systole, resulting in dynamic LVOT obstruction. This phenomenon was also observed in one other case. Furthermore, the lateral view of the LVOT orifice revealed a projection of the prosthetic valve into the LVOT, causing mechanical LVOT obstruction. The finding that translational motion of the prosthetic valve with an inflexible mitral annulus results in dynamic LVOT obstruction may support the hypothesis that annular rigidity causes dynamic LVOT obstruction after mitral valve repair with a rigid prosthetic ring.
借助二维超声心动图对二尖瓣置换或修复术后患者左心室流出道（LVOT）梗阻的机制进行了研究。然而，对于主动脉根部与二尖瓣环之间空间关系的解读，二维显示有时并不充分，因为它可能无法在每个层面同时捕捉到这些结构。我们基于磁共振图像开发了一种在三维空间中阐明这种关系的方法。我们定义了左心室流出道开口（LVOT孔）的位置，依次由一个肌肉区域（即室间隔边缘）和一个环形区域（即二尖瓣前叶瓣环）组成。在本文中，我们展示了从八名正常受试者之一获取的图像数据，并将其与两名术前患有退行性二尖瓣反流、随后接受保留腱索二尖瓣置换术（其中前腱索重新附着于前瓣环）的患者之一的数据进行比较。在正常受试者中，二尖瓣环在收缩期呈现出灵活的形状变化，保持了足够的LVOT孔大小。在患者中，人工瓣膜在收缩期表现出平移运动，导致动态LVOT梗阻。在另一例中也观察到了这种现象。此外，LVOT孔的侧视图显示人工瓣膜向LVOT内突出，导致机械性LVOT梗阻。人工瓣膜平移运动且二尖瓣环僵硬导致动态LVOT梗阻这一发现可能支持以下假设：使用刚性人工瓣环进行二尖瓣修复后，瓣环僵硬会导致动态LVOT梗阻。
