title: Mechanical Interaction of an Expanding Coiled Stent with a Plaque-Containing Arterial Wall: A Finite Element Analysis.
abstract: Wall injury is observed during stent expansion within atherosclerotic arteries, related in part to stimulation of the inflammatory process. Wall stress and strain induced by stent expansion can be closely examined by finite element analysis (FEA), thus shedding light on procedure-induced sources of inflammation. The purpose of this work was to use FEA to examine the interaction of a coiled polymer stent with a plaque-containing arterial wall during stent expansion. An asymmetric fibrotic plaque-containing arterial wall model was created from intravascular ultrasound (IVUS) images of a diseased artery. A 3D model for a coil stent at unexpanded state was generated in SolidWorks. They were imported into ANSYS for FEA of combined stent expansion and fibrotic plaque-distortion. We simulated the stent expansion in the plaqued lumen by increasing balloon pressure from 0 to 12 atm in 1 atm step. At increasing pressure, we examined how the expanding stent exerts forces on the fibrotic plaque and vascular wall components, and how the latter collectively resist and balance the expansive forces from the stent. Results show the expanding coiled stent creates high stresses within the plaque and the surrounding fibrotic capsule. Lower stresses were observed in adjacent medial and adventitial layers. High principal strains were observed in plaque and fibrotic capsule. The results suggest fibrotic capsule rupture might occur at localized regions. The FEA/IVUS method can be adapted for routine examination of the effects of the expansion of selected furled stents against IVUS-reconstructed diseased vessels, to improve stent deployment practices.
authors.affiliation: Division of Pediatric Cardiothoracic Surgery, Department of Cardiovascular Thoracic Surgery, University of Texas at Southwestern Medical Center of Dallas, Dallas, TX, 75390-9130, USA. tre.welch@utsouthwestern.edu.
authors.forename: Tré R
authors.initials: TR
authors.lastname: Welch
authors.affiliation: Department of Surgery, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9130, USA.|Bioengineering Department, University of Texas at Arlington, Arlington, TX, 76019, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Eberhart
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9130, USA.
authors.forename: Subhash
authors.initials: S
authors.lastname: Banerjee
authors.affiliation: Bioengineering Department, University of Texas at Arlington, Arlington, TX, 76019, USA.
authors.forename: Cheng-Jen
authors.initials: CJ
authors.lastname: Chuong
mesh_terms: D001696:Biomechanical Phenomena; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008955:Models, Cardiovascular; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D015607:Stents; D018084:Ultrasonography, Interventional
keywords: Bioresorbable stent; IVUS; Plaque; Structural analysis