Al-Maisary Sameer, Engelhardt Sandy, Graser Bastian, Wolf Ivo, Karck Matthias, De Simone Raffaele
Department of Cardiac Surgery, Heidelberg University Hospital, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.
Department of Computer-Assisted Medical Intervention, German Cancer Research Center (DKFZ), Heidelberg, Germany.
J Cardiothorac Surg. 2017 Jan 30;12(1):8. doi: 10.1186/s13019-017-0571-y.
Ring sizing for mitral valve annuloplasty is conventionally done intraoperatively using specific 'sizer' instruments, which are placed onto the valve tissue. This approach is barely reproducible since different sizing strategies have been established among surgeons. The goal of this study is to virtually apply different sizing methods on the basis of pre-repair echocardiography to find out basic differences between sizing strategies.
In three-dimensional echocardiographs of 43 patients, the mitral annulus and the contour of the anterior mitral leaflet were segmented using MITK Mitralyzer software. Similarly, three-dimensional virtual models of Carpentier-Edwards Physio II annuloplasty rings and their corresponding sizers were interactively generated from computer tomography images. For each patient, the matching annuloplasty ring was selected repeatedly according to popular sizing strategies, such as the height of anterior mitral leaflet, the intercommissural distance and the surface area of anterior mitral leaflet. The areas of the selected rings were considered as the neo-surface area of the mitral annulus after implantation.
The sizing of the mitral valve according to the height of anterior mitral leaflet (mean ring size = 29.9 ± 3.90), intercommissural distance (mean ring size = 37.5 ± 1.92) or surface area of anterior mitral leaflet (mean ring size = 32.7 ± 3.3) led to significantly different measurements (p ≤ 0.01). In contrary to intercommissural distance, height and surface area of the anterior mitral leaflet exhibited significant variations between the patients (p ≤ 0.01). The sizing according to the height of anterior mitral leaflet led to the maximal reduction of the mitral annulus surface area followed by the sizing according to the surface area of anterior mitral leaflet and finally by the intercommissural distance.
This novel comprehensive computer-based analysis reveals that the surveyed sizing methods led to the selection of significantly different annuloplasty rings and therefore underscore the ambiguity of routinely applied annuloplasty sizing strategies.
二尖瓣环成形术的环尺寸测量传统上是在手术中使用特定的“尺寸测量仪”器械进行的，这些器械放置在瓣膜组织上。由于外科医生之间已经确立了不同的尺寸测量策略，这种方法几乎无法重复。本研究的目的是在修复前超声心动图的基础上虚拟应用不同的尺寸测量方法，以找出尺寸测量策略之间的基本差异。
在43例患者的三维超声心动图中，使用MITK Mitralyzer软件对二尖瓣环和二尖瓣前叶轮廓进行分割。同样，从计算机断层扫描图像中交互式生成Carpentier-Edwards Physio II瓣环成形环及其相应尺寸测量仪的三维虚拟模型。对于每位患者，根据流行的尺寸测量策略，如二尖瓣前叶高度、瓣间距离和二尖瓣前叶表面积，反复选择匹配的瓣环成形环。所选环的面积被视为植入后二尖瓣环的新表面积。
根据二尖瓣前叶高度（平均环尺寸 = 29.9 ± 3.90）、瓣间距离（平均环尺寸 = 37.5 ± 1.92）或二尖瓣前叶表面积（平均环尺寸 = 32.7 ± 3.3）进行二尖瓣尺寸测量，导致测量结果存在显著差异（p ≤ 0.01）。与瓣间距离相反，二尖瓣前叶的高度和表面积在患者之间表现出显著差异（p ≤ 0.01）。根据二尖瓣前叶高度进行尺寸测量导致二尖瓣环表面积减少最多，其次是根据二尖瓣前叶表面积进行尺寸测量，最后是根据瓣间距离进行尺寸测量。
这种基于计算机的新型综合分析表明，所研究的尺寸测量方法导致选择了显著不同的瓣环成形环，因此强调了常规应用的瓣环成形尺寸测量策略的模糊性。
