title: An in vivo pilot study of a microporous thin film nitinol-covered stent to assess the effect of porosity and pore geometry on device interaction with the vessel wall.
abstract: Sputter-deposited thin film nitinol constructs with various micropatterns were fabricated to evaluate their effect on the vessel wall in vivo when used as a covering for commercially available stents. Thin film nitinol constructs were used to cover stents and deployed in non-diseased swine arteries. Swine were sacrificed after approximately four weeks and the thin film nitinol-covered stents were removed for histopathologic evaluation. Histopathology revealed differences in neointimal thickness that correlated with the thin film nitinol micropattern. Devices covered with thin film nitinol with a lateral × vertical length = 20 × 40 µm diamond pattern had minimal neointimal growth with well-organized cell architecture and little evidence of ongoing inflammation. Devices covered with thin film nitinol with smaller fenestrations exhibited a relatively thick neointimal layer with inflammation and larger fenestrations showed migration of inflammatory and smooth muscle cells through the micro fenestrations. This "proof-of-concept" study suggests that there may be an ideal thin film nitinol porosity and pore geometry to encourage endothelialization and incorporation of the device into the vessel wall. Future work will be needed to determine the optimal pore size and geometry to minimize neointimal proliferation and in-stent stenosis.
authors.affiliation: 1 Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, USA.|2 Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Youngjae
authors.initials: Y
authors.lastname: Chun
authors.affiliation: 3 Advanced Development & Medical Affairs, NeuroSigma, Inc., Los Angeles, CA, USA.
authors.forename: Colin P
authors.initials: CP
authors.lastname: Kealey
authors.affiliation: 4 Pediatric Cardiology, Mattel Children's Hospital, University of California, Los Angeles, CA, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Levi
authors.affiliation: 5 Division of Vascular Surgery, Ronald Reagan UCLA Medical Center, UCLA Surg-Vascular, Los Angeles, CA, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Rigberg
authors.affiliation: 1 Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Chen
authors.affiliation: 5 Division of Vascular Surgery, Ronald Reagan UCLA Medical Center, UCLA Surg-Vascular, Los Angeles, CA, USA.
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Tillman
authors.affiliation: 6 Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA, USA.
authors.forename: K P
authors.initials: KP
authors.lastname: Mohanchandra
authors.affiliation: 1 Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Mahdis
authors.initials: M
authors.lastname: Shayan
authors.affiliation: 6 Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA, USA.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Carman
mesh_terms: D000497:Alloys / Q000737:chemistry*; D001158:Arteries / Q000166:cytology* / Q000502:physiology*; D001807:Blood Vessel Prosthesis; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D010865:Pilot Projects; D016062:Porosity; D015607:Stents; D013499:Surface Properties
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C013616:nitinol
keywords: Coronary artery disease; neointimal hyperplasia; peripheral artery disease; restenosis; thin film nitinol