04 Fakultät Energie-, Verfahrens- und Biotechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/5
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Item Open Access Vascular response on a novel fibrin-based coated flow diverter(2021) Mühl-Benninghaus, Ruben; Fries, Frederik; Kießling, Mara; Tomori, Toshiki; Krajewski, Stefanie; Simgen, Andreas; Bauer, Sabina; Hey, Natascha; Brynda, Eduard; Taborska, Johanka; Riedel, Tomáš; Reith, Wolfgang; Cattaneo, Giorgio; Brochhausen, ChristophDue to thromboembolic complications and in-stent-stenosis after flow diverter (FD) treatment, the long-term use of dual antiplatelet treatment (DAPT) is mandatory. The tested nano-coating has been shown to reduce material thrombogenicity and promote endothelial cell proliferation in vitro. We compared the biocompatibility of coated (Derivo Heal) and non-coated (Derivo bare) FDs with DAPT in an animal model. Derivo® bare (n = 10) and Derivo® Heal (n = 10) FD were implanted in the common carotid arteries (CCAs) of New Zealand white rabbits. One additional FD, alternately a Derivo bare (n = 5) or Derivo Heal (n = 5), was implanted in the abdominal aorta (AA) for assessment of the patency of branch arteries. Histopathological examinations were performed after 28 days. Angiography was performed before and after FD implantation and at follow-up. Statistical analysis of the included specimens showed complete endothelialization of all FDs with no significant differences in neointima thickness between Derivo® bare and Derivo® Heal (CCA: p = 0.91; AA: p = 0.59). A significantly reduced number of macrophages in the vessel wall of the Derivo Heal was observed for the CCA (p = 0.02), and significantly reduced fibrin and platelet deposition on the surface of the Derivo Heal was observed for the AA. All branch arteries of the stented aorta remained patent. In this animal model, the novel fibrin-based coated FD showed a similar blood and tissue compatibility as the non-coated FD.Item Open Access Investigation of tracer gas transport in a new numerical model of lung acini(2022) Schmidt, Christoph; Joppek, Christoph; Trinkmann, Frederik; Takors, Ralf; Cattaneo, Giorgio; Port, JohannesObstructive pulmonary diseases are associated with considerable morbidity. For an early diagnosis of these diseases, inert gas washouts can potentially be used. However, the complex interaction between lung anatomy and gas transport mechanisms complicates data analysis. In order to investigate this interaction, a numerical model, based on the finite difference method, consisting of two lung units connected in parallel, was developed to simulate the tracer gas transport within the human acinus. Firstly, the geometries of the units were varied and the diffusion coefficients ( D ) were kept constant. Secondly, D was changed and the geometry was kept constant. Furthermore, simple monoexponential growth functions were applied to evaluate the simulated data. In 109 of the 112 analyzed curves, monoexponential function matched simulated data with an accuracy of over 90%, potentially representing a suitable numerical tool to predict transport processes in further model extensions. For total flows greater than 5 × 10 -4 ml/s, the exponential growth constants increased linearly with linear increasing flow to an accuracy of over 95%. The slopes of these linear trend lines of 1.23 µl -1 ( D = 0.6 cm 2 /s), 1.69 µl -1 ( D = 0.3 cm 2 /s), and 2.25 µl -1 ( D = 0.1 cm 2 /s) indicated that gases with low D are more sensitive to changes in flows than gases with high D .Item Open Access In vivo comparison of braided (Accero) and laser-cut intracranial stents (Acclino, Credo) : evaluation of vessel responses at subacute and mid-term follow-up in a rabbit model(2020) Mühl-Benninghaus, Ruben; Tomori, Toshiki; Krajewski, Stefanie; Dietrich, Philipp; Simgen, Andreas; Yilmaz, Umut; Brochhausen, Christoph; Kießling, Mara; Reith, Wolfgang; Cattaneo, GiorgioThis study aimed to investigate in vivo two stent technologies, with particular emphasis on thrombogenicity and inflammatory vessel remodeling processes. The micro-stents tested in this study were developed for intracranial aneurysm treatment. In our study twelve, New Zealand white rabbits were divided into two groups: 18 laser-cut stents (LCS) and 18 braided stents (BS) were impanated without admiration of antiplatelet medication. Three stents were implanted into each animal in the common carotid artery, subclavian artery, and abdominal aorta. Digital subtraction angiography was performed before and after stent implantation and at follow-up for the visualization of occurring In-stent thromboembolism or stenosis. The Stents were explanted for histopathological examination at two different timepoints, after 3 and 28 days. Angiographically neither in-stent thrombosis nor stenosis for both groups was seen. There was a progressive increase in the vessel diameter, which was more pronounced for BS than for LCS. We detected a higher number of thrombi adherent to the foreign material on day 3 for BS. On day 3, the neointima was absent, whereas the complete formation observed was on day 28. There was no significant difference between both groups regarding the thickness of the neointima. The in vivo model of our study enabled the evaluation of blood and vessel reactions for two different stent technologies. Differences in vessel dimension and tissue around the stents were observed on day 28. Histological analysis on day 3 enabled the assessment of thrombotic reactions, representing an important complementary result in long-term studies.