title: Evaluation of functionality and biological response of the multilayer flow modulator in porcine animal models.
abstract: BACKGROUND
  This study outlines the use of non-aneurysmal porcine animal models to study device functionality and biological response of the Multilayer Flow Modulator (MFM) (Cardiatis, Isnes, Belgium), with an emphasis on preclinical device functionality and biological response characteristics in an otherwise healthy aorta.
  
  
  METHODS
  Twelve animals were implanted with the study device in the abdominal aorta, in 6 animals for 1 month and 6 animals for 6 months. Upon completion of the study period, each animal underwent a necropsy to examine how the implanted device had affected the artery and surrounding tissue. Neointima and stenosis formation were recorded via morphometry, and endothelialization via histopathological analysis.
  
  
  RESULTS
  The MFM devices were delivered to their respective implantation sites without difficulty. Six of the implanted stents were oversized with percentages ranging from 2.6% to 18.8%. Statistical analysis was carried out and showed no significance between the regular sized stent group and oversized stent group for neointimal area (P=0.17), neointimal thickness (P=0.17), and percentage area stenosis (P=0.65). Histopathological findings showed in most areas flattened endothelium like cells lined the luminal surface of the neointima. Scanning electron microscopy also showed the devices were well tolerated, inciting only a minimal neointimal covering and little fibrin or platelet deposition. Neointimal thickness of 239.7±55.6 μm and 318.3±130.4 μm, and percentage area stenosis of 9.6±2.6% and 12.6±5% were recorded at 1 and 6 months respectively. No statistical differences were found between these results.
  
  
  CONCLUSIONS
  The MFM devices were delivered to their respective implantation sites without difficulty and incited little neointimal and stenosis formation in the aorta, affirming its functionality and biocompatibility.
authors.affiliation: Department of Vascular and Endovascular Surgery, Western Vascular Institute, University Hospital Galway, Newcastle Road, Galway, Ireland - sherif.sultan@hse.ie.
authors.forename: Sherif
authors.initials: S
authors.lastname: Sultan
authors.forename: Edel P
authors.initials: EP
authors.lastname: Kavanagh
authors.forename: Niamh
authors.initials: N
authors.lastname: Hynes
authors.forename: Edward B
authors.initials: EB
authors.lastname: Diethrich
mesh_terms: D000818:Animals; D008422:Materials Testing; D023421:Models, Animal; D011474:Prosthesis Design; D015607:Stents; D013552:Swine; D014656:Vascular Surgical Procedures