Implantation of a self-expandable prototype transcatheter pulmonary valve in a pig model: an experimental study

Introduction: Reconstruction of the right ventricular outflow tract is recommended for 20% of patients with congenital heart defects. The risks of complications during repeated open cardiac surgeries stimulated the implantation of the pulmonary artery valve according to the P. Bonhoeffer method developed more than 20 years ago. Modern transcatheter technologies enable implantation of the pulmonary artery valve in patients after transannular plastic surgery in combination with pulmonary regurgitation and not only when using biological valve conduits. Objective: The aim of this study was to evaluate the short- and mid-term outcomes of implanting a prototype of a self-expanding, transcatheter pulmonary artery valve in an experimental pig model. This study assesses the efficacy and safety of the novel device in comparison to traditional surgical methods. Methods: A total of 8 experimental animals were included in this study. The object of the study was a transcatheter self-expandable valve-containing prosthetic device designed for implantation in the pulmonary artery, which consisted of an external supporting mesh scaffold made of a titanium nickelide as well as sheathing and a leaflet mechanism. Results: In the early postoperative period, there was a minor complication in the form of a 1.5 cm small paraprosthetic fistula, which spontaneously closed in the long-term. No mortality or other complications were observed in the mid-term follow-up period. We also noted an insignificant increase in transvalvular gradients, with a gradient of 11 (8-13) mm Hg after surgery, and 16 (12-19) mm Hg in 6 months, p = 0.79. Upon removal animals from the experiment, the supporting scaffolds of the valves were intact without any damage. The valve surface was smooth, without traces of blood clots or cellular infiltration. Microscopically, there was no evidence of structural injuries and no signs of calcification after von Kossa staining. Conclusion: The experimental transcatheter-implanted valve demonstrated good short- and mid-term efficacy without significant pulmonary insufficiency signs and pressure gradient on the bioprosthesis. However, the fracture of the radial arches in the crown of the device, which occurred in 25% of cases, attests the demand on creating a more durable structure through reinforcement of rigidity or increasing the number of radial arches.