Seki Tatsuya, Jimuro Katsuyoshi, Shingu Yasushige, Wakasa Satoru, Katoh Hiroki, Ooka Tomonori, Tachibana Tsuyoshi, Kubota Suguru, Ohashi Toshiro, Matsui Yoshiro
Department of Cardiovascular and Thoracic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan.
Laboratory of Micro-Biomechanics, Division of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido University, Sapporo, Japan.
J Artif Organs. 2019 Jun;22(2):126-133. doi: 10.1007/s10047-018-1084-8. Epub 2018 Nov 19.
Ideally, an annuloplasty ring's shape should be changed intraoperatively if mitral valve repair is unsuccessful because of a short coaptation length or systolic anterior motion. Several post-implantation adjustable rings have been developed, but they are not freely deformable and are unsuitable for asymmetric repair of the valvular annulus. We developed a novel thermally deformable mitral annuloplasty ring to address these problems and assessed the ring's mechanical properties and its effect on the mitral valve anatomy. This ring was made of polycaprolactone. Tensile and bending tests were performed to evaluate the ring's mechanical properties. The ratio of the transverse and septal-lateral length was determined as 4:3. Using 10 pig hearts, we measured the post-deformation coaptation length and minimum distance from the coaptation to the ventricular septum, which is a factor of abnormal systolic anterior motion of the mitral valve. In the mechanical tests, the ring's yield point was greater than the deformation force of the annulus in humans. In pigs with deformation from "4:3" to "4:2", the coaptation length was significantly increased in each mitral valve part. In pigs with deformation from "4:3" to "4:4", the minimum distance from the coaptation to the ventricular septum was significantly increased. Asymmetrical ring deformation increased the coaptation length only at the deformed area. In conclusion, this new thermally deformable mitral annuloplasty ring could be "order-made" to effectively change the coaptation length in all parts of the mitral valve and the distance from the coaptation to septum post-deformation via intraoperative heating.
理想情况下，如果二尖瓣修复因瓣叶对合长度短或收缩期前向运动而失败，应在术中改变瓣环成形环的形状。已经开发了几种植入后可调节环，但它们不能自由变形，不适用于瓣膜环的不对称修复。我们开发了一种新型热可变形二尖瓣瓣环成形环来解决这些问题，并评估了该环的力学性能及其对二尖瓣解剖结构的影响。这个环由聚己内酯制成。进行拉伸和弯曲试验以评估环的力学性能。确定横向与间隔-外侧长度之比为4:3。使用10个猪心脏，我们测量了变形后的瓣叶对合长度以及从对合处到室间隔的最小距离，这是二尖瓣异常收缩期前向运动的一个因素。在力学测试中，环的屈服点大于人体瓣环的变形力。在从“4:3”变形为“4:2”的猪中，每个二尖瓣部分的瓣叶对合长度均显著增加。在从“4:3”变形为“4:4”的猪中，从对合处到室间隔的最小距离显著增加。不对称的环变形仅在变形区域增加了瓣叶对合长度。总之，这种新型热可变形二尖瓣瓣环成形环可以“定制”，通过术中加热有效地改变二尖瓣所有部分的瓣叶对合长度以及变形后从对合处到间隔的距离。
