Department of Surgery, University of California, San Francisco, California; Veterans Affairs Medical Center, San Francisco, California.
School of Medicine, University of California, San Francisco, California.
Ann Thorac Surg. 2014 May;97(5):1496-503. doi: 10.1016/j.athoracsur.2013.12.036. Epub 2014 Mar 13.
Recurrent mitral regurgitation after mitral valve (MV) repair for degenerative disease occurs at a rate of 2.6% per year and reoperation rate progressively reaches 20% at 19.5 years. We believe that MV repair durability is related to initial postoperative leaflet and annular geometry with subsequent leaflet remodeling due to stress. We tested the hypothesis that MV leaflet and annular stress is increased after MV repair.
Magnetic resonance imaging was performed before and intraoperative three-dimensional (3D) transesophageal echocardiography was performed before and after repair of posterior leaflet prolapse in a single patient. The repair consisted of triangular resection and annuloplasty band placement. Images of the heart were manually co-registered. The left ventricle and MV were contoured, surfaced, and a 3D finite element (FE) model was created. Elements of the posterior leaflet region were removed to model leaflet resection and virtual sutures were used to repair the leaflet defect and attach the annuloplasty ring.
The principal findings of the current study are the following: (1) FE simulation of MV repair is able to accurately predict changes in MV geometry including changes in annular dimensions and leaflet coaptation; (2) average posterior leaflet stress is increased; and (3) average anterior leaflet and annular stress are reduced after triangular resection and mitral annuloplasty.
We successfully conducted virtual mitral valve prolapse repair using FE modeling methods. Future studies will examine the effects of leaflet resection type as well as annuloplasty ring size and shape.
退行性病变二尖瓣（MV）修复术后，每年约有 2.6%的患者会发生二尖瓣反流复发，19.5 年后再次手术的比率逐渐达到 20%。我们认为 MV 修复的耐久性与初始术后瓣叶和瓣环的几何形状有关，随后由于应力导致瓣叶重塑。我们假设 MV 修复后瓣叶和瓣环的应力会增加。
对一名后瓣叶脱垂患者在术前和术中进行了磁共振成像（MRI），在术前和术后进行了三维（3D）经食管超声心动图（TEE）检查。修复包括三角形切除和瓣环成形带放置。心脏图像通过手动配准。左心室和 MV 被描绘出来，进行了表面处理，并创建了一个 3D 有限元（FE）模型。后瓣叶区域的元素被移除，以模拟瓣叶切除，并使用虚拟缝线来修复瓣叶缺陷并固定瓣环成形环。
目前研究的主要发现如下：（1）MV 修复的 FE 模拟能够准确预测 MV 几何形状的变化，包括瓣环尺寸和瓣叶对合的变化；（2）平均后瓣叶的应力增加；（3）三角形切除和二尖瓣环成形术后，平均前瓣叶和瓣环的应力降低。
我们成功地使用 FE 建模方法进行了虚拟二尖瓣脱垂修复。未来的研究将研究瓣叶切除类型以及瓣环成形环的大小和形状的影响。
