{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T10:02:06Z","timestamp":1789639326188,"version":"4.0.0"},"reference-count":28,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:00:00Z","timestamp":1789603200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Methods Protoc.","MPs"],"abstract":"<jats:p>Background: Endovascular exclusion of popliteal artery aneurysms (PAAs) with long covered stent-grafts is valuable for patients unfit for open surgery but is undermined by late stent thrombosis, even in fully scaffolded segments without kinking, a failure best clarified by computational fluid dynamics (CFD), which requires anatomically accurate 3D models\u2014difficult to obtain in the mobile knee. Methods: In this prospective, single-centre study, consecutive patients undergoing endovascular PAA repair over 24 months (\u226520 patients) underwent CT angiography in three knee positions (full extension, 45\u00b0 and 90\u00b0 flexion). Every treated limb was included, with limb as the unit of analysis. Images undergo a geometric pipeline: segmentation in 3D Slicer, then refinement in MeshLab, Meshmixer and VMTK. Meshes are converted to hexahedral volumes (ANSA Cadense) and simulated under pulsatile flow (ANSYS Fluent). Primary endpoints are time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT) over the stented segment, plus the surface proportion meeting thrombogenic criteria; positions are compared via linear mixed-effects models with limb nested within patient. Results: The protocol reproducibly yields watertight, artefact-free models preserving physiological morphology and supporting TAWSS, OSI and RRT quantification across knee positions. Conclusions: This protocol standardizes generation of CFD-ready popliteal geometries, enabling positional analysis of stent thrombosis.<\/jats:p>","DOI":"10.3390\/mps9050133","type":"journal-article","created":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T08:03:17Z","timestamp":1789632197000},"page":"133","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Position-Dependent Hemodynamics of Popliteal Artery Stent Grafts: The POPFLEX Study"],"prefix":"10.3390","volume":"9","author":[{"given":"Christos","family":"Chronis","sequence":"first","affiliation":[{"name":"Vascular Surgery Department, Medical School, University of Crete, 71110 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1360-5423","authenticated-orcid":false,"given":"Konstantinos","family":"Tzirakis","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, School of Engineering, Hellenic Mediterranean University, 71004 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6792-5003","authenticated-orcid":false,"given":"Nikolaos","family":"Kontopodis","sequence":"additional","affiliation":[{"name":"Vascular Surgery Department, Medical School, University of Crete, 71110 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9878-6053","authenticated-orcid":false,"given":"Nikolaos","family":"Galanakis","sequence":"additional","affiliation":[{"name":"Interventional Radiology Unit, Medical School, University of Crete, 71003 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2537-2893","authenticated-orcid":false,"given":"Elias","family":"Kehagias","sequence":"additional","affiliation":[{"name":"Interventional Radiology Unit, Medical School, University of Crete, 71003 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christos V.","family":"Ioannou","sequence":"additional","affiliation":[{"name":"Vascular Surgery Department, Medical School, University of Crete, 71110 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1016\/j.jvs.2005.04.049","article-title":"Open repair versus endovascular treatment for asymptomatic popliteal artery aneurysm","volume":"42","author":"Antonello","year":"2005","journal-title":"J. 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