Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, Calif. 94305-5247, USA.
J Thorac Cardiovasc Surg. 2010 May;139(5):1114-22. doi: 10.1016/j.jtcvs.2009.12.014.
To assess the effects of annuloplasty rings on anterior mitral leaflet dimensions.
Sixteen radiopaque markers were sutured evenly spaced over the surface of the anterior mitral leaflet in 57 sheep. The following rings were implanted in a releasable fashion: size 28-mm Cosgrove-Edwards band (Edwards Lifesciences, Irvine, Calif) (n = 11), rigid saddle-shaped annuloplasty ring (St Jude Medical Inc, St Paul, Minn) (n = 12), Carpentier-Edwards Physio (Edwards Lifesciences) (n = 12), IMR-ETlogix (Edwards Lifesciences) (n = 10), and GeoForm (Edwards Lifesciences) (n = 12). Under acute open chest conditions, 4-dimensional marker coordinates were measured using biplane videofluoroscopy with the annuloplasty ring inserted and after annuloplasty ring release. Septal-lateral and commissure-commissure dimensions were calculated from opposing marker pairs on the septal-lateral and commissure-commissure aspect of the anterior mitral leaflet at end diastole and end systole. To assess changes in anterior mitral leaflet shape, a "planarity index" was assessed by calculating the root mean square values as distances of the 16 anterior mitral leaflet markers to a best fit anterior mitral leaflet plane at end systole.
At end diastole, anterior mitral leaflet septal-lateral and commissure-commissure dimensions did not change with the Cosgrove ring compared with control, whereas the rigid saddle-shaped annuloplasty ring and Physio, IMR-ETlogix, and GeoForm rings reduced anterior mitral leaflet commissure-commissure but not septal-lateral anterior mitral leaflet dimensions. At end systole, the septal-lateral anterior mitral leaflet dimension was smaller with the IMR-ETlogix and GeoForm rings, but did not change with the Cosgrove ring, rigid saddle-shaped annuloplasty ring, and Physio ring. Anterior mitral leaflet shape was unchanged in all 5 groups.
With no changes in anterior mitral leaflet planarity, the 4 complete, rigid rings (rigid saddle-shaped annuloplasty ring, Physio, IMR-ETlogix, and GeoForm) reduced the anterior mitral leaflet commissure-commissure dimension at end diastole. The IMR-ETlogix and GeoForm rings decreased the septal-lateral anterior mitral leaflet dimension at end systole, probably as the result of inherent disproportionate downsizing. These changes in anterior mitral leaflet geometry could perturb the stress patterns, which in theory may affect repair durability.
评估二尖瓣成形环对二尖瓣前叶尺寸的影响。
将 16 个不透射线的标记物均匀地缝合在 57 只绵羊的二尖瓣前叶表面上。以可释放的方式植入以下环：28mm Cosgrove-Edwards 带（爱德华兹生命科学公司，加利福尼亚州欧文）（n=11）、刚性鞍形瓣环成形环（圣犹达医疗公司，明尼苏达州圣保罗）（n=12）、Carpentier-Edwards Physio（爱德华兹生命科学公司）（n=12）、IMR-ETlogix（爱德华兹生命科学公司）（n=10）和 GeoForm（爱德华兹生命科学公司）（n=12）。在急性开胸条件下，在插入二尖瓣成形环和释放二尖瓣成形环后，使用双平面荧光透视术测量 4 维标记物的坐标。在舒张末期和收缩末期，从二尖瓣前叶的间隔-外侧和交界-交界侧面的相对标记物对计算间隔-外侧和交界-交界尺寸。为了评估二尖瓣前叶形状的变化，通过计算 16 个二尖瓣前叶标记物在收缩末期到最佳拟合二尖瓣前叶平面的均方根值来评估“平面度指数”。
舒张末期，与对照相比，Cosgrove 环对二尖瓣前叶间隔-外侧和交界-交界尺寸没有改变，而刚性鞍形瓣环成形环和 Physio、IMR-ETlogix 和 GeoForm 环减小了二尖瓣前叶交界-交界，但不改变间隔-外侧二尖瓣前叶尺寸。在收缩末期，IMR-ETlogix 和 GeoForm 环的二尖瓣前叶间隔-外侧尺寸较小，但 Cosgrove 环、刚性鞍形瓣环成形环和 Physio 环没有变化。在所有 5 组中，二尖瓣前叶的形状都没有改变。
在二尖瓣前叶平面度没有变化的情况下，4 个完整的刚性环（刚性鞍形瓣环成形环、Physio、IMR-ETlogix 和 GeoForm）在舒张末期减小了二尖瓣前叶交界-交界的尺寸。IMR-ETlogix 和 GeoForm 环在收缩末期减小了二尖瓣前叶间隔-外侧的尺寸，可能是由于固有不成比例的缩小。这些二尖瓣前叶几何形状的变化可能会改变应力模式，理论上可能会影响修复的耐久性。
