FULL PAPER 1700292 (1 of 6) © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.mbs-journal.de Development of a Polymer-Based Biodegradable Neurovascular Stent Prototype: A Preliminary In Vitro and In Vivo Study Omid Nikoubashman,* Sarah Heringer, Katalin Feher, Marc-Alexander Brockmann, Bernd Sellhaus, Alice Dreser, Kathrin Kurtenbach, Rastislav Pjontek, Stefan Jockenhövel, Joachim Weis, Fabian Kießling, Thomas Gries, and Martin Wiesmann DOI: 10.1002/mabi.201700292 As vessel remodeling is complete after 3–6 months, mechanical stent support is only necessary during this period. [2] This is why a biodegradable stent that is resorbed after six months may be pre- ferred to a permanently implanted stent. [3] A dissolvable stent facilitates follow-up imaging and consecutive surgery. [4] These advantages make biodegradable stents a promising option for interventional neu- rovascular procedures. Studies with biodegradable cardio- vascular stents implied that such stents may improve vessel remodeling, lumen gain, and long-term arterial healing compared to metallic stents. [5] In recent years, lactic acid-based polymer stents have emerged as the most common type of biodegradable stent. [3,6] Currently, two lactic acid-based stents (ABSORB stent; Abbott Vascular, Santa Clara, CA and DESolve stent; Elixir Medical Corpora- tion, Sunnyvale, CA) have received CE mark approval for coronary artery use. [7] While biodegradable stents are becoming more common in cardiovascular interventions, biodegradable stents are not established in neurovascular interventions, yet. Cardiovascular stents cannot simply be used in neurovascular procedures, as Biodegradable Stents Biodegradable stents are not established in neurovascular interventions. In this study, mechanical, radiological, and histological characteristics of a stent proto- type developed for neurovascular use are presented. The elasticity and brittle- ness of PLA 96/4, PLDL 70/30, PCL, and PLGA 85/15 and 10/90 polymers in in vitro experiments are first analyzed. After excluding the inapt polymers, degra- dability and mechanical characteristics of 78 PLGA 85/15 and PLGA 10/90 stent prototypes are analyzed. After excluding PLGA 10/90 stents because of rapid loss of mass PLGA 85/15 stents in porcine in vivo experiments are analyzed. Angiographic occlusion rates 7 d, 1 month, 3 months, and 6 months after stent implantation are assessed. Histological outcome measures are the presence of signs of inflammation, endothelialization, and the homogeneity of degradation after six months. One case of stent occlusion occurs within the first 7 d. There is a prominent foreign-body reaction with considerable mononuclear and minor granulocytic inflammation combined with incomplete fragmental degradation of the struts. It is possible to produce a stent prototype with dimensions that fit the typical size of carotid arteries. Major improvements concerning throm- bogenicity, degradation, and inflammatory response are required to produce biodegradable stents that are suitable for neurovascular interventions. Prof. O. Nikoubashman, S. Heringer, Dr. R. Pjontek, Prof. M. Wiesmann Department of Diagnostic and Interventional Neuroradiology University Hospital RWTH Aachen University Pauwelsstr. 30, 52074 Aachen, Germany E-mail: onikoubashman@ukaachen.de K. Feher, Dr. K. Kurtenbach, Prof. S. Jockenhövel, Prof. T. Gries Institute of Tissue Engineering and Textile Implants RWTH Aachen University Otto-Blumenthal-Str. 1, 52074 Aachen, Germany Prof. M.-A. Brockmann Department of Diagnostic and Interventional Neuroradiology University Hospital Mainz 55131 Mainz, Germany Dr. B. Sellhaus, A. Dreser, Dr. K. Kurtenbach, Dr. R. Pjontek, Prof. S. Jockenhövel, Prof. J. Weis Institute of Neuropathology University Hospital RWTH Aachen University Pauwelsstr. 30, 52074 Aachen, Germany Prof. S. Jockenhövel Institute of Applied Medical Engineering University Hospital RWTH Aachen University Pauwelsstr. 20, 52074 Aachen, Germany Prof. F. Kießling Institute of Experimental Molecular Imaging University Hospital RWTH Aachen University Pauwelsstr. 30, 52074 Aachen, Germany The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/mabi.201700292. 1. Introduction Endovascular stenting is a common treatment option for extracranial and intracranial neurovascular arterial stenosis. [1] Macromol. Biosci. 2018, 1700292