Lee Candice Y, Wong Joshua K, Sauer Jude S, Gorea Heather R, Martellaro Angelo J, Sifain Andrew R, Knight Peter A
From the *University of Rochester Medical Center, Rochester, NY USA; and †LSI SOLUTIONS, Inc, Victor, NY USA.
Innovations (Phila). 2016 Nov/Dec;11(6):400-406. doi: 10.1097/IMI.0000000000000316.
Mitral valve (MV) chordae replacements can be technically challenging. Technology that remotely delivers and accurately secures artificial chordae may reduce the learning curve and improve the reliability of MV repairs.
The technology involved two devices: a remote suturing device for delivery of expanded polytetrafluoroethylene (ePTFE) suture to the papillary muscle and a Coaxial titanium suture fastener (TF) device with integrated saline infusion for real-time determination of chordae length during fixation. A mechanical model simulating MV chordae tension in a beating heart quantified the durability of 120 coaxially fastened ePTFE sutures using TF over time. Investigation of the technology was performed in ex vivo porcine, ovine, and in situ cadaver hearts, whereas live-tissue testing was conducted in a survivor ovine model. Mitral valve repair procedures involved the iatrogenic induction of mitral regurgitation by the resection of one to two native MV chordae, followed by implantation of ePTFE suture using the technology. Epicardial echocardiography, saline infusion testing, and histologic analysis evaluated MV competence, repair integrity, and long-term healing.
Durability testing of ePTFE suture secured with TF demonstrated no degradation of TF pull-apart forces of for 440 million cycles. Mitral valve repairs using the technology were performed in eight sheep; four demonstrating proof of concept and four survived for an average of 6.5 months after completion of the procedure. At reoperation, echocardiography demonstrated trace to no mitral regurgitation with near complete endothelialization of the TF and artificial chordae.
This technology successfully enabled the implantation of artificial chordae while providing real-time adjustment of chordae length during MV repair. These results encourage further investigation of its use clinically.
二尖瓣（MV）腱索置换术在技术上可能具有挑战性。能够远程输送并准确固定人工腱索的技术可能会缩短学习曲线并提高二尖瓣修复的可靠性。
该技术涉及两种装置：一种用于将膨体聚四氟乙烯（ePTFE）缝线输送至乳头肌的远程缝合装置，以及一种带有集成盐水输注功能的同轴钛缝线固定器（TF）装置，用于在固定过程中实时测定腱索长度。一个模拟跳动心脏中二尖瓣腱索张力的机械模型对120根使用TF同轴固定的ePTFE缝线随时间的耐久性进行了量化。该技术在离体猪心、羊心和原位尸体心脏中进行了研究，而在存活的羊模型中进行了活组织测试。二尖瓣修复手术包括通过切除一到两根天然二尖瓣腱索人为诱发二尖瓣反流，然后使用该技术植入ePTFE缝线。心外膜超声心动图、盐水输注测试和组织学分析评估了二尖瓣功能、修复完整性和长期愈合情况。
用TF固定的ePTFE缝线的耐久性测试表明，在4.4亿次循环中TF的拉开力没有下降。使用该技术对八只羊进行了二尖瓣修复；四只证明了概念验证，四只在手术后平均存活了6.5个月。再次手术时，超声心动图显示微量至无二尖瓣反流，TF和人工腱索几乎完全内皮化。
该技术成功实现了人工腱索的植入，同时在二尖瓣修复过程中提供了腱索长度的实时调整。这些结果鼓励进一步研究其在临床上的应用。
