title: External aortic root support: a histological and mechanical study in sheep.
abstract: OBJECTIVE
  Personalized external aortic root support has completed initial evaluation and has technology appraisal in the UK for patients with Marfan syndrome for use as an alternative to root replacement. Its long-term success in preventing aortic dissection remains uncertain. Here, we report a study in sheep to establish whether the externally supporting mesh, as used clinically, is biologically incorporated. The strength of the resulting mesh/artery composite has been tested.
  
  
  METHODS
  The carotid artery of growing sheep (n=6) was enclosed in a mesh sleeve made of a polymer, polyethylene terephthalate. After a predefined interval of 4-6 months, a length of the artery was excised, including the sleeved and unsleeved portions, and was stress tested and examined histologically.
  
  
  RESULTS
  One animal died of pneumonia 7 days after implantation. Comparing sleeved with normal segments, the overall thickness was increased and there was a fibrotic sheet in the periarterial space. The overall vessel wall architecture was preserved in all specimens. Although media thickness of ensleeved arteries was smaller and in one animal mild oedema was found in one quadrant of the outer part of the media. There was a significant increase in stiffness and maximum tensile strength of the supported segments compared with normal arterial tissue.
  
  
  CONCLUSIONS
  Polyethylene terephthalate mesh, as used for the external support of the dilated aortic root in Marfan syndrome, becomes incorporated in the periadventitial tissue of the carotid artery of sheep. Limited thinning of the media, without any signs of inflammation or medial necrosis, was visible. There was a significantly greater tensile strength in the carotid artery/mesh composite compared with the unsleeved carotid artery.
authors.affiliation: Centre of Experimental Cardiac Surgery, KUL, Leuven, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Verbrugghe
authors.forename: Erik
authors.initials: E
authors.lastname: Verbeken
authors.forename: John
authors.initials: J
authors.lastname: Pepper
authors.forename: Tom
authors.initials: T
authors.lastname: Treasure
authors.forename: Bart
authors.initials: B
authors.lastname: Meyns
authors.forename: Bart
authors.initials: B
authors.lastname: Meuris
authors.forename: Paul
authors.initials: P
authors.lastname: Herijgers
authors.forename: Filip
authors.initials: F
authors.lastname: Rega
mesh_terms: D000818:Animals; D001011:Aorta / Q000254:growth & development / Q000473:pathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D017536:Carotid Artery, Common / Q000254:growth & development / Q000473:pathology / Q000601:surgery*; D011093:Polyethylene Terephthalates; D011474:Prosthesis Design; D012756:Sheep; D013718:Tensile Strength; D013997:Time Factors; D059289:Vascular Stiffness
chemical_list: D011093:Polyethylene Terephthalates
keywords: Blood vessel prosthesis; Experimental; Thoracic aortic aneurysm