Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA 94305-5247, USA.
J Thorac Cardiovasc Surg. 2011 Feb;141(2):345-53. doi: 10.1016/j.jtcvs.2010.10.015.
The study objective was to quantify the effects of different annuloplasty rings on mitral leaflet septal-lateral tenting areas during acute myocardial ischemia.
Radiopaque markers were implanted along the central septal-lateral meridian of the mitral valve in 30 sheep: 1 each to the septal and lateral aspects of the mitral annulus and 4 and 2 along the anterior and posterior mitral leaflets, respectively. Ten true-sized Carpentier-Edwards Physio, Edwards IMR ETLogix, and GeoForm annuloplasty rings (Edwards Lifesciences, Irvine, Calif) were inserted in a releasable fashion. Marker coordinates were obtained using biplane videofluoroscopy with ring inserted at baseline (RING_BL) and after 90 seconds of left circumflex artery occlusion (RING_ISCH). After ring release, another dataset was acquired before (No_Ring_BL) and after left circumflex artery occlusion (No_Ring_ISCH). Anterior and posterior mitral leaflet tenting areas were computed at mid-systole from sums of marker triangles with the midpoint between the annular markers being the vertex for all triangles.
Compared with No_Ring_BL, mitral regurgitation grades and all tenting areas significantly increased with No_Ring_ISCH. Compared with No_Ring_ISCH, (1) all rings significantly prevented mitral regurgitation and reduced all tenting areas; (2) Edwards IMR ETLogix and GeoForm rings reduced posterior mitral leaflet area, but not anterior mitral leaflet tenting area, to a significantly greater extent than the Carpentier-Edwards Physio ring; and (3) Edwards IMR ETLogix and GeoForm rings affected tenting areas similarly.
In response to acute left ventricular ischemia, disease-specific functional/ischemic mitral regurgitation rings (Edwards IMR ETLogix, GeoForm) more effectively reduced posterior mitral leaflet area, but not anterior mitral leaflet tenting area, compared with true-sized physiologic rings (Carpentier-Edwards Physio). Despite its radical 3-dimensional shape and greater amount of mitral annular septal-lateral downsizing, the GeoForm ring did not reduce tenting areas more than the Edwards IMR ETLogix ring, suggesting that further reduction in tenting areas in patients with FMR/IMR may not be effectively achieved on an annular level.
本研究旨在定量评估不同二尖瓣成形环对急性心肌缺血时二尖瓣瓣叶间隔-侧壁膨出面积的影响。
在 30 只绵羊的二尖瓣中央间隔-侧壁子午线上植入不透射线标记物：二尖瓣环间隔和侧壁各 1 个，前、后瓣叶各 4 个和 2 个。以可释放方式插入 10 个真实尺寸的 Carpentier-Edwards Physio、Edwards IMR ETLogix 和 GeoForm 成形环（爱德华兹生命科学公司，加利福尼亚州欧文）。在插入成形环时（RING_BL）和左回旋支闭塞 90 秒后（RING_ISCH），使用双平面荧光透视术获取标记物坐标。在释放成形环后，在左回旋支闭塞前（No_Ring_BL）和后（No_Ring_ISCH）获取另一个数据集。在收缩中期，通过标记物三角形的总和计算前、后瓣叶膨出面积，所有三角形的顶点为环标记物之间的中点。
与 No_Ring_BL 相比，No_Ring_ISCH 时二尖瓣反流程度和所有膨出面积均显著增加。与 No_Ring_ISCH 相比，（1）所有成形环均显著预防二尖瓣反流并减少所有膨出面积；（2）Edwards IMR ETLogix 和 GeoForm 环显著减小后瓣叶面积，但不减小前瓣叶膨出面积，比 Carpentier-Edwards Physio 环更为显著；（3）Edwards IMR ETLogix 和 GeoForm 环对膨出面积的影响相似。
在急性左心室缺血时，与生理环（Carpentier-Edwards Physio）相比，特定疾病的功能性/缺血性二尖瓣成形环（Edwards IMR ETLogix、GeoForm）更有效地减小后瓣叶面积，但不减小前瓣叶膨出面积。尽管 GeoForm 环具有激进的 3 维形状和更大程度的二尖瓣环间隔-侧壁缩小，但它并未比 Edwards IMR ETLogix 环更有效地减小膨出面积，这表明在 FMR/IMR 患者中，瓣环水平上进一步减小膨出面积可能无法有效实现。
