A simplified D-shaped model of the mitral annulus to facilitate CT-based sizing before transcatheter mitral valve implantation
A simplified D-shaped model of the mitral annulus to facilitate CT-based sizing before transcatheter mitral valve implantation
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DOI：
10.1016/j.jcct.2014.09.009
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发表时间：
2014-11-01
影响因子：
5.4
通讯作者：
Leipsic, Jonathon
中科院分区：
文献类型：
--
作者：
Blanke, Philipp;Dvir, Danny;Leipsic, Jonathon
背景：经过几十年的解剖学和超声心动图研究，二尖瓣环的非平面、鞍形结构已经被很好地建立起来。目的：明确二尖瓣置入术中基于CT的简化“D”型二尖瓣环评估方法，并与传统的“马鞍型”二尖瓣环评估方法进行比较。方法：对28例重度功能性二尖瓣反流患者的二尖瓣环轮廓进行手动分割，并利用心电门控舒张期CT数据集识别纤维三角。与传统的鞍状环不同，D形环被定义为在前方受TT距离的限制，不包括主动脉与三尖瓣的连续性。结果：D形环的投影面积、周长和间隔-侧向距离明显小于D形环(11.2+/-2.7vs13.0+/-3.0cm2；124.1+/-15.1vs136.0+/-15.5 mm；垂直于4.0vs40.1vs4.9 mm；P<.001)。TT距离相同(32.7±4.1 mm)。鞍状环的假想左心室流出道间隙显著低于D形环(10.7+/-2.2vs17.5+/-3.0 mm；P<；.001)。结论：通过在TT距离处截断鞍状环轮廓的前角，更平坦和更小的D形环更少地投射到左心室流出道上，从而产生比鞍形入路更大的假设性左心室流出道间隙。基于CT的二尖瓣环评估可能有助于术前评估，确保适当的患者和器械选择。(C)2014年心血管计算机断层扫描学会。版权所有。
Background: The nonplanar, saddle-shaped structure of the mitral annulus has been well established through decades of anatomic and echocardiographic study. Its relevance for mitral annular assessment for transcatheter mitral valve implantation is uncertain.Objective: Our objectives are to define the methodology for CT-based simplified "D-shaped" mitral annular assessment for transcatheter mitral valve implantation and compare these measurements to traditional "saddle-shaped" mitral annular assessment.Methods: The annular contour was manually segmented, and fibrous trigones were identified using electrocardiogram-gated diastolic CT data sets of 28 patients with severe functional mitral regurgitation, yielding annular perimeter, projected area, trigone-to-trigone (TT) distance, and septal-lateral distance. In contrast to the traditional saddle-shaped annulus, the D-shaped annulus was defined as being limited anteriorly by the TT distance, excluding the aortomitral continuity. Hypothetical left ventricular outflow tract (LVOT) clearance was assessed.Results: Projected area, perimeter, and septal-lateral distance were found to be significantly smaller for the D-shaped annulus (11.2 +/- 2.7 vs 13.0 +/- 3.0 cm(2); 124.1 +/- 15.1 vs 136.0 +/- 15.5 mm; and 32.1 perpendicular to 4.0 vs 40.1 perpendicular to 4.9 mm, respectively; P < .001). TT distances were identical (32.7 +/- 4.1 mm). Hypothetical LVOT clearance was significantly lower for the saddle-shaped annulus than for the D-shaped annulus (10.7 +/- 2.2 vs 17.5 +/- 3.0 mm; P < .001).Conclusion: By truncating the anterior horn of the saddle-shaped annular contour at the TT distance, the resulting more planar and smaller D-shaped annulus projects less onto the LVOT, yielding a significantly larger hypothetical LVOT clearance than the saddle-shaped approach. CT-based mitral annular assessment may aid preprocedural sizing, ensuring appropriate patient and device selection. (C) 2014 Society of Cardiovascular Computed Tomography. All rights reserved.