In Vitro Mechanical Behavior and In Vivo Healing Response of a New Generation Biodegradable-Polymer Coated Thin Strut Sirolimus Eluting Stent

Pawel Gasior Division of Cardiology and Structural Heart Diseases, Medical University of Silesia, Katowice, Silesia, Poland Lukasz Pyka 3rd Department of Cardiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze, Silesia, Poland Michal Hawranek 3rd Department of Cardiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze, Silesia, Poland Michal Garbacz 3rd Department of Cardiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze, Silesia, Poland Mariusz Gasior 3rd Department of Cardiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze, Silesia, Poland Wojciech Wojakowski Division of Cardiology and Structural Heart Diseases, Medical University of Silesia, Katowice, Silesia, Poland Andrzej Lekston 3rd Department of Cardiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze, Silesia, Poland

Background: Recent advancements in drug-eluting stents (DES) technologies reduced the rate of repeat revascularization. However, treatment complex lesions still remain challenging. In this study we aimed to evaluate the biomechanical behavior and vascular healing profile of a new generation biodegradable-polymer coated thin strut sirolimus-eluting stent (Alex NG, Balton, Poland).

Methods: In vitro biomechanical testing was performed under static conditions. We compared Alex NG with the commercially available previous generation platform (Alex Plus, Balton, Poland) and the leading DES (Orsiro, Biotronik, Germany). We investigated the difference in stent designs and the results obtained after post-expansion with larger balloon sizes. A total of 6 domestic swines were implanted with Alex NG (n=12) and Alex Plus (n=6) for healing evaluation at 30 days

Results: With overexpansion 1mm above nominal diameter no fractures or significant deformations were observed in the light microscopy in all studied groups. Furthermore, postdilatation 1.5mm above the nominal diameter revealed no fractures in Alex NG and Orsiro. Also, the largest cell opening diameter was observed in the Alex NG both at the nominal and upsized diameters. Optical coherence tomography analysis demonstrated comparable neoinitimal thickness at 30 days in Alex NG when compared to Alex Plus (respectively: 0,14±0,03 vs. 0,14±0,05, p=0,887). Histology evaluation is pending, and the results will be presented at the meeting.

Conclusion: The new-generation Alex NG demonstrated improved biomechanical behavior to the previous generation platform (Alex Plus) with the results similar to the Orsiro stent. Furthermore, Alex NG demonstrated favorable healing profile in the imaging in vivo study.