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Novel synthetic selectively degradable vascular prostheses: a preliminary implantation study.

AbstractBACKGROUND:
Vascular grafts perform less well than autologous arterial or vein grafts. The purpose of this study was to evaluate the short-term performance of selectively biodegradable filament-wound vascular prostheses, comprising elastomeric poly(ether urethane) (Lycra) scaffolds and flexible, hydrophilic biodegradable coatings.
MATERIALS AND METHODS:
Two types of selectively biodegradable vascular grafts were manufactured, comprising a filament-wound Lycra scaffold, subsequently coated with a biodegradable poly(ethylene glycol)/poly(lactic acid) (PELA) block copolymer. The two types of grafts differed in both the overall porosity of the scaffold and the hydrophilicity of the biodegradable constituent. A 60-mm-long and 6-mm-diameter filament-wound and polytetrafluoroethylene (ePTFE) grafts were implanted as interposition prostheses, randomly, at the right- and left-side carotid arteries.
RESULTS:
Implantation studies proved the grafts to be patent and pulsatile for periods of up to 3 months. Increasing the scaffold porosity and enhancing the hydrophilicity of the biodegradable component improved both the transmural tissue ingrowth process and the vascularization of the prosthesis wall. Also, a well-adhered peripheral tissue and a thin, uniform intima and endothelial lining were obtained. All ePTFE graft controls, although patent, were rather stiff and nonpulsatile. A thick pseudointima, poorly attached to the prosthesis inner surface, was observed. The compliance of the wet grafts was significantly higher than in the dry state, stemming mainly from the water-plasticizing effect on the biodegradable component. The grafts explanted after a period of 6 weeks exhibited compliance only slightly lower than that of the wet grafts. After 12 weeks, however, the hoop compliance was 20% lower than that prior to implantation. At 100 mm Hg, for example, the original compliance of the wet graft was 2.5%/100 mm Hg decreasing to 2.0%/100 mm Hg after a 3-month implantation. The compliance reduction with implantation is attributed to the ingrowth of the perigraft tissue as revealed by the histological study. A compliance of 2.0%/100 mm Hg is slightly better than that of a standard PTFE graft with an original compliance of 1.6%/100 mm Hg. Yet it is still an order of magnitude smaller than that of a canine carotid artery.
CONCLUSIONS:
The improved mechanical properties and enhanced healing of the highly porous filament-wound Lycra scaffold graft coated with hydrophilic biodegradable PELA has the potential of being a highly effective small caliber prosthetic graft.
AuthorsU Izhar, H Schwalb, J B Borman, G R Hellener, A Hotoveli-Salomon, G Marom, T Stern, D Cohn
JournalThe Journal of surgical research (J Surg Res) Vol. 95 Issue 2 Pg. 152-60 (Feb 2001) ISSN: 0022-4804 [Print] United States
PMID11162039 (Publication Type: Journal Article)
CopyrightCopyright 2000 Academic Press.
Chemical References
  • Lactates
  • Polymers
  • Polyurethanes
  • polyethylene oxide-polylactic acid block copolymer
  • Polyethylene Glycols
  • Polytetrafluoroethylene
Topics
  • Absorbable Implants
  • Animals
  • Blood Vessel Prosthesis
  • Blood Vessel Prosthesis Implantation
  • Carotid Artery, Common
  • Cell Adhesion
  • Dogs
  • Endothelium, Vascular (cytology, physiology)
  • Lactates (pharmacokinetics)
  • Models, Animal
  • Polyethylene Glycols (pharmacokinetics)
  • Polymers (pharmacokinetics)
  • Polytetrafluoroethylene (pharmacokinetics)
  • Polyurethanes
  • Time Factors
  • Tunica Intima (cytology, physiology)

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