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Analyse de l'écoulement physiologique dans un stent coronarien : Application à la caractérisation des zones de resténose pariétale.

Abstract : Arterial stenoses may be treated with a procedure that consists of restoring the arterial lumen with an endoprothesis (stent). The post-operative rate of restenosis still remains high (20%). Researches on the mechanisms of the restenosis process have demonstrated a systematic correlation between the sites of restenosis and those of low wall shear stress. Stent design (and thus the wall shear stress induced by the stent geometry) has a preponderant role in the phenomenon of restenosis. In order to improve the post-operative results, we propose to understand, analyze and simulate the hemodynamic flow through a stented left coronary artery. This research is composed of experimental and numerical work.

Experimental measurements were performed with a 2D PIV (Particle Image Velocimetry) technique. A plane model made of PMMA (scale factor of 50) was employed with adequate similarity conditions concerning changes in shape and scale.

The numerical part was carried out using a commercial code (Star-CD) for 2D and 3D configurations of a whole realistic stent design (Helistent model from Hexacath, Paris, France). Advanced meshing techniques (Pro-AM) were applied to model this complex geometry. The applied flow was steady and based on several physiological flow rates values. Complementary studies consisted of a numerical comparison between Newtonian and non-Newtonian flow. This study aimed to locate and precisely quantify the velocity field, zone of recirculation, vorticity and wall shear stress distribution.

Finally, studies from the literature on interactions between wall shear stress level and endothelial cell or smooth muscle cell responses allow us to estimate the stent pattern leading to a higher restenosis risk area.
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Submitted on : Thursday, April 13, 2006 - 11:31:21 AM
Last modification on : Monday, October 19, 2020 - 11:02:00 AM
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Nicolas Bénard. Analyse de l'écoulement physiologique dans un stent coronarien : Application à la caractérisation des zones de resténose pariétale.. Sciences du Vivant [q-bio]. Université de Poitiers, 2005. Français. ⟨tel-00012134⟩

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