Preclinical safety and performance evaluation of a highly-flexible peripheral polytetrafluoroethylene-covered stent.

Background: Sten graft implantation faces challenges such as deliverability issues, fracture risk, and subsequent restenosis. Recent advancements have introduced thinner coatings for increased flexibility and improved biocompatibility. The aim herein was to assess the safety and performance of a highly flexible cobalt-chromium stent covered with polytetrafluoroethylene (PTFE) in a preclinical model.

Methods: In total 6 PTEF-covered stent grafts 6mm x 38mm cobalt-chromium, (Solaris BXTM, Scitech Produtos Medicos) were implanted compared to 5 controls ( BeGraftTM, Bentley InnoMed GmbH) in the iliac arteries of 11 swine. Stents were evaluated with angiography, high-definition IVUS, and histology for 28 days.

Results: All animals underwent successful implantation with 100% survival at follow-up. At 28 days, there was no statistically significant difference in MLD compared to baseline in both groups (test, 5.2 ± 0.7 mm vs 5.3 ± 0.6 mm, p = 0.8; control, 4.9 ± 0.7 mm vs 5.1 ± 0.5 mm, p = 0.8), indicating no LLL (test, -0.2 ± 0.16 vs control, -0.18 ± 0.16 mm; p = 0.8). IVUS revealed a tendency for the less neointimal area in the test group (3.75 ± 0.9mm² vs 5.69 ± 2.2 mm²; p = 0.08), resulting in a tendency toward higher % AS in the control arm (14.07 ± 3.42% vs 20 ± 7%; p = 0.1). Microscopic evaluation revealed minimal vascular injury (test 0.1 ± 0.3 vs control 0.1 ± 0.1) and complete endothelialization coverage (test, 3.2 ± 0.8 vs control 3.8 ± 0.3) in both groups, with minimal inflammation(test vs. control: per strut 0.02 ± 0.06 vs. 0.14 ± 0.22; neointimal 1.2 ± 0.6 vs 1.1 ± 0.4; medial 0.3 ± 0.4 vs 0.3 ± 0.4).

Conclusion: Solaris BXTM demonstrated highly flexible and biocompatible, with minimal vascular injury, and reduced neointimal hyperplasia compared to the control.