An Automated Expanded Polytetrafluoroethylene Suturing and Coaxial Fastener System for Mitral Chordae Replacement: Strength, Feasibility, and Healing

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Abstract

Objective

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.

Methods

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.

Results

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.

Conclusions

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.

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