Spacers, such as FORMA (Edwards Lifescience) or Mitraspacer, are used to treat mitral regurgitation or tricuspid regurgitations. However, they require external therapeutic liquid filler injection into the spacer device. This should be leak-tight over the time of implantation, which is a major limitation in device design. Here, we propose a self-expandable spacer with a nitinol inner mesh and expanded poly (tetrafluoroethylene) (ePTFE) coating that also functions as a spacer. We designed nitinol 3D mesh templates, coated with a commercially available low and high durometer ePTFE membrane. Finally, we implanted the spacer into a swine pulmonary artery and right atrium (superior vena cava) as an intervention technique. Twenty-four swine were used, except in two cases suspected of procedural infection. The results were analyzed in the remaining 22 cases and all devices were easily delivered and had good function in self-expansion and implantation. After eight weeks, all individuals were examined for gross and pathological analysis to determine the biological safety of the device. There was no evidence of damage or other abnormalities and increased postoperative endothelialization outside of ePTFE coatings. In conclusion, this study suggests using a self-expandable spacer to complement the medical limitations of the existing filling-type spacer devices.

Objectives. In our previous study, we suggested the novel septal traversing technique as effective and safe in catheter-based approach for septal myocardium. However, it is limited by its dependence on the septal perforator vein. This study aimed to evaluate the Cobra catheter as a backup catheter to overcome this limitation in swine. Methods. We designed the guiding Cobra catheter. It consisted of three major parts (the external pull-wire steerable distal tip, the C-shaped shaft, and the steering adjustment handle). We tested the difference in force between the guidewire passing through the muscle and the vessel wall using a push-pull gauge. We performed a septal wire engage procedure in swine using the Cobra catheter. The guidewire engagement of the septal vein and Cobra catheter were compared visually and histopathologically. Results. A total of ten swine were enrolled in this study. The success rate was 100 under fluoroscopy. The experiments confirmed the medical potential of the septal approach even in a location irrelevant to the septal perforator vein anatomy and confirmed that the wire passed well in the target direction in the harvested heart. There was no serious physical damage or pathological abnormalities in the vessel wall and myocardium. Conclusion. These results showed that the novel Cobra catheter with a septal vein-independent trans-septal approach may be a safe and effective alternative for the treatment of structural heart diseases.