title: The performance of a small-calibre graft for vascular reconstructions in a senescent sheep model.
abstract: There is an acute clinical need for small-calibre (<6 mm) vascular grafts for surgery. The aim of this study was to evaluate the long-term performance of a small-calibre graft produced from a nanocomposite biomaterial, polyhedral oligomeric silsesquioxane poly(carbonate-urea)urethane (POSS-PCU), in a large animal model following Good Manufacturing Practice (GMP) and Good Laboratory Practice (GLP) protocols. Grafts were characterised and implanted into the left carotid artery (LCA) of senescent sheep (n = 11) for a period of 9 months. In vivo compliance and blood flow rates were measured using ultrasound wall tracking software and a Transonic flow meter. Graft patency and degree of intimal hyperplasia (IH) were examined at the study end point. Seven of the POSS-PCU grafts were free from thrombosis, IH, calcification and aneurysmal dilation, with 4 occluding within 14 days. All of the ePTFE controls (n = 4) were found to be occluded by day 32. The lumen of the patent POSS-PCU grafts was free from any cellular deposits, whilst perigraft tissue could be seen to be infiltrating into the body of the graft from the adventitia. No significant differences were detected between the blood flow rates (p = 0.3693) and compliance (p = 0.9706) of the POSS-PCU grafts and the native artery, either post-operatively or after 9 months implantation. Small-calibre vascular grafts produced from POSS-PCU offer a viable option for the clinical use in revascularisation procedures with a patency rate of 64%.
authors.affiliation: UCL Centre for Nanotechnology & Regenerative Medicine, Division of Surgery and Interventional Science, University College London, United Kingdom; Centre of Mathematics and Physics in The Life Sciences and Experimental Biology (CoMPLEX), University College London, United Kingdom.
authors.forename: Maqsood
authors.initials: M
authors.lastname: Ahmed
authors.affiliation: Royal Free London NHS Foundation Trust Hospital, London, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Hamilton
authors.affiliation: UCL Centre for Nanotechnology & Regenerative Medicine, Division of Surgery and Interventional Science, University College London, United Kingdom; Royal Free London NHS Foundation Trust Hospital, London, United Kingdom. Electronic address: A.Seifalian@UCL.AC.UK.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001696:Biomechanical Phenomena; D001792:Blood Platelets / Q000166:cytology; D001807:Blood Vessel Prosthesis; D002448:Cell Adhesion; D004730:Endothelium, Vascular / Q000637:transplantation*; D005260:Female; D006965:Hyperplasia / Q000473:pathology; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D053761:Nanocomposites / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry; D012756:Sheep; D013927:Thrombosis / Q000473:pathology; D018675:Toxicity Tests; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes
keywords: Biocompatibility; In vivo test; Nanocomposite; Polyurethane; Vascular graft