gms | German Medical Science

Introduction: Biodegradable polymeric stents have demonstrated a potential alternative to standard metal stents, but to date, human experience with such devices is limited. The aim of this study is to assess the technical feasibility and biocompatibility of a novel biodegradable stent based on poly(L-lactide) (PLLA) and poly(4-hydroxybutyrate) (P4HB) for peripheral vascular applications.

Material and methods: Biodegradable polymeric stents (PLLA/P4HB) or non-biodegradable bare-metal stents (316L) were implanted interventionally into both common carotid arteries of 7 female pigs via the left common iliac artery (8F-sheath). The stents were mounted on a balloon catheter (5.0x40 mm) and expanded with either 8 bar (PLLA/P4HB) or 9 bar (316L). The pigs were administered peroral aspirin (250 mg) and clopidogrel (75 mg) starting 3 days before the procedure until the end of the study. After 4 weeks, before explanting the stented vessel segments, contrast enhanced angiography of the carotid vessels was performed to assess in-stent restenosis, and magnetic resonance tomography of the brain was performed to detect ischemic lesions.

Results: One pig died during the procedure due to heart arrest caused by bleeding at the iliac access. All other animals survived until the end of the study without developing neurological complications. Pushability and trackability of the stents was assessed in this study. The polymeric stents showed a significantly higher in-stent restenosis (43-58%) compared to the bare-metal stents (p≤0.001). Mean value and standard deviation were 52.05% (2.59) for polymeric stents and 35.65% (3.71) for bare-metal stents. No brain infarction was detected.

Conclusion: The overall results in an interventional endovascular porcine model demonstrate the applicability and mechanical competence of the developed polymeric vascular stent. The higher restenosis of polymeric stents in this study deserves further research, but was in accordance with our previous results of a surgical animal model. Development of a drug-eluting polymeric stent will be a feasible approach to improve vascular response.