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Evidence of vicious cycle in mitral regurgitation with prolapse : Secondary tethering due to primary prolapse demonstrated by 3-dimensional echocardiography exacerbates regurgitation

二尖瓣反流伴脱垂恶性循环的证据：三维超声心动图显示原发性脱垂引起的二次束缚加剧了反流

基本信息

批准号：
21500458
负责人：
OTSUJI Yutaka
金额：
$ 3万
依托单位：
University of Occupational and Environmental Health, Japan
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2011
项目状态：
已结题

项目摘要

Background : In patients with mitral valve prolapse(MVP), non-prolapsed leaflets are often apically tented. We hypothesized 1) that secondary left ventricular(LV) dilatation due to primary mitral regurgitation(MR) causes this leaflet tenting/tethering and 2) that secondary tethering further exacerbates malcoaptation and contributes to MR severity.Methods and Results : Three-dimensional(3D) transesophageal echocardiography(TEE) was performed in 25 patients with posterior leaflet(PML) prolapse with an intact anterior leaflet(AML) and 20 controls. From 3D zoom datasets, 11 equidistant antero-posterior cut planes of the MV at mid-systole were obtained. In each plane, tenting area of non-prolapsed leaflet and prolapse area of prolapsed leaflet were measured. Prolapse/tenting volume of each region was obtained as the product of inter-slice distance and the prolapse/tenting area. AML tenting volume and whole leaflet prolapse/tenting volume were then obtained. The severity of MR was quantified by vena contracta area(VCA) extracted from color 3DTEE datasets. AML tenting volume was significantly larger in patients with PML prolapse compared with that in controls(1.2±0.5 vs. 0.6±0.2 ml/m^2, p<0.001). Multivariate regression analysis identified independent contributions to AML tenting volume from an increase in mid-systolic LV volume(r=0.79, p<0.001) along with annular dilatation. Multivariate regression analysis identified independent contributions to MR severity(VCA) from both whole leaflet tenting volume(r=0.63, p<0.001) as well as prolapse volume(r=0.60, p<0.001). AML tenting volume decreased along with LV volume post-repair(n=7, p<0.01).Conclusion : These results suggest that primary MVP with MR causes secondary mitral leaflet tethering due to LV dilatation and annular dilatation, which further exacerbates valve leakage, constituting a vicious cycle that would suggest a pathophysiologic rationale for early surgical repair.

背景：在二尖瓣脱垂(MVP)患者中，非脱垂的小叶通常是顶端的帐篷。我们假设：1)由于二尖瓣返流(MR)导致的继发性左室扩张导致二尖瓣关闭不全，2)二次拴系进一步加剧了吻合不良，并导致MR的严重程度。方法和结果：对25例有完整前叶(AML)的后叶脱垂患者和20例对照组进行了三维(3D)经食道超声心动图(TEE)检查。从3D Zoom数据集获得了11个等距的收缩中期MV的前后切面。在每个平面上测量非脱垂叶的帐篷面积和脱垂叶的脱垂面积。取各区域的下垂/帐篷体积，作为切片间距与下垂/帐篷面积的乘积。然后计算出急性髓系白血病的帐篷体积和整个小叶脱垂/帐篷体积。MR的严重程度由彩色3DTEE数据集提取的静脉收缩面积(VCA)来量化。急性髓细胞白血病脱垂患者的帐篷容量明显大于对照组(1.2±0.5vs.0.6±0.2ml/m^2，p&lt；0.001)。多变量回归分析表明，急性髓细胞白血病患者的帐篷容量独立于收缩中期左心室容量的增加(r=0.79，p&t；0.001)和环状扩张。多元回归分析显示，影响MR严重程度的独立因素是整个小叶的体积(r=0.63p&lt；0.001)和下垂体积(r=0.6，p&lt；0.001)。急性髓细胞白血病患者术后随左室血容量的减少而减少(n=7，p&lt；0.01)。结论：MR合并MVP后，由于左室扩张和瓣环扩张，继发性二尖瓣小叶拴系，进一步加重瓣膜渗漏，形成恶性循环，为早期手术修复提供了病理生理学基础。