Impact of statins on vascular scaffolds response in porcine carotid arteries

Abstract

Surgical treatments of arterial occlusive disease with fully absorbable polymeric scaffolds, as a potential alternative to permanent metallic stents, are increasingly penetrating the clinical field. An addition part of the management of patients suffering from vascular diseases is the administration of statins. In this study, absorbable x-ray marked PLLA-based polymer scaffolds and permanent bare-metal stents (BMS) were implanted interventionally into both common carotid arteries (CCA) of 6 healthy female pigs via the left common iliac artery (8F-sheath). The pigs were administered dual antiplatelet drugs oral starting 3 days before the procedure until the end of the study. In Addition, the pigs received atorvastatin orally, beginning 5 days prior to surgery and lasting until the study ended. Stented CCA segments were explanted after 4 weeks, and processed for quantitative histomorphometry, and estimation of vascular inflammation and injury scores. Polymer scaffolds showed a decreased residual lumen area and higher stenosis after 4 weeks (6.41 ± 0.83 mm² and 40.52 ± 5.01%) as compared to the bare-metal reference stent (15.17 ± 0.896 mm² and 7.80 ± 0.88%). After 4 weeks, inflammation score were higher in the polymer group (1.30 ± 0.37) compared to the BMS group (0.42 ± 0.18). In contrast, the BMS showed a slightly elevated vascular injury score (0.85 ± 0.12), as compared to the polymer (0.60 ± 0.23) group. In this preclinical model, the new absorbable polymeric scaffolds showed similar technical feasibility and safety for vascular application as the permanent metal stents. Although no positive trends were observed with oral treatment with atorvastatin, further optimization with a dual-loaded coating is still reasonable. In addition, reduced strut thickness of the polymer scaffolds would have potential to positively impact tissue ingrowth between struts and should be considered in future work on stent design.

Keywords

• absorbable polymeric scaffold
• x-ray marked
• statin
• carotid artery stenting
• experimental porcine model