Vascular Response Toward an Absorbable Sirolimus-eluting Polymeric Scaffold for Vascular Application in a Model of Normal Porcine Carotid Arteries

• Published in: Annals of vascular surgery Vol. 79; pp. 324 - 334
• Main Authors: Kischkel, Sabine, Bünger, Carsten M., Grabow, Niels, Erdle, Benjamin, Kabelitz, Method, Moreth, Felix, Martin, David P., Williams, Simon F., Reske, Thomas, Schmitz, Klaus-Peter, Schareck, Wolfgang, Püschel, Anja
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.02.2022
• Subjects: Absorbable Implants; absorbable polymeric scaffold; Angioplasty, Balloon - adverse effects; Angioplasty, Balloon - instrumentation; Animals; Cardiovascular Agents - administration & dosage; carotid artery stenting; Carotid Artery, Common - diagnostic imaging; Carotid Artery, Common - pathology; Carotid Stenosis - etiology; Carotid Stenosis - pathology; drug; experimental porcine study; Inflammation - etiology; Inflammation - pathology; Materials Testing; Models, Animal; poly(4-hydroxybutyrate); poly(L-lactide); Polyesters; Prosthesis Design; Sirolimus - administration & dosage; Sus scrofa; Time Factors; carotid artery stenting; absorbable polymeric scaffold; experimental porcine study; poly(L-lactide); poly(4-hydroxybutyrate); drug
• ISSN: 0890-5096; 1615-5947
• DOI: 10.1016/j.avsg.2021.10.001

Fully absorbable polymeric scaffolds, as a potential alternative to permanent metallic stents, are entering the clinical field. The aim of this study is to assess the in vivo biocompatibility of a novel Sirolimus-eluting (SIR) absorbable scaffold based on poly(L-lactide) (PLLA) and poly(4-hydroxybutyrate) (P4HB) for interventional application. Absorbable PLLA/P4HB scaffolds either loaded with SIR coating or unloaded scaffolds were implanted interventionally into common carotid arteries of 14 female. Bare metal stents (BMS) served as control. Peroral dual anti-platelet therapy was administered throughout the study. Stented common carotid arteries segments were explanted after 4 weeks, and assessed histomorphometrically. The absorbable scaffolds showed a decreased residual lumen area and higher stenosis after 4 weeks (PLLA/P4HB: 6.56 ± 0.41 mm² and 37.56 ± 4.67%; SIR-PLLA/P4HB: 6.90 ± 0.58 mm² and 35.60 ± 3.15%) as compared to BMS (15.29 ± 1.86 mm² and 7.65 ± 2.27%). Incorporation of SIR reduced the significantly higher inflammation of unloaded scaffolds however not to a level compared to bare metal stent (PLLA/P4HB: 1.20 ± 0.19; SIR-PLLA/P4HB: 0.96 ± 0.24; BMS: 0.54 ± 0.12). In contrast, the BMS showed a slightly elevated vascular injury score (0.74 ± 0.15), as compared to the PLLA/P4HB (0.54 ± 0.20) and the SIR-PLLA/P4HB (0.48 ± 0.15) groups. In this preclinical model, the new absorbable polymeric (SIR-) scaffolds showed similar technical feasability and safety for vascular application as the permanent metal stents. The higher inflammatory propensity of the polymeric scaffolds was slightly reduced by SIR-coating. A smaller strut thickness of the polymeric scaffolds might have been a positive effect on tissue ingrowth between the struts and needs to be addressed in future work on the stent design.