012 * INHIBITION OF RESTENOSIS OF THE VEIN GRAFT WITH DEGRADABLE PLGA VASCULAR EXTERNAL SHEATHS WITH SLOW-RELEASE BOSENTAN

Abstract

Objectives: A vascular external sheath was designed to inhibit restenosis of vein grafts. Method(s): Using the biodegradable material poly(lactic-co-glycolic acid) (PLGA) and fibrin a high porosity external sheath carrying bosentan with a stratified internal spiral structure was made by grouping mould extraction and low temperature deposition techniques. Rabbits underwent carotid bypass with ipsilateral jugular vein without external sheath (A) with external sheath (B) or with external sheath carrying bosentan (C). Result(s): Postoperative ultrasonography indicated that the change rate of the diameter of vein grafts of group A was much higher than that of group B or C (P < 0.01). The change rate of velocity peak of group C was higher than that of group B or C (P < 0.01). The sheaths degraded completely 9 weeks after operation and the histologic examination showed that the ratio of long/short diameter of vein grafts was much higher in group A (P < 0.05). The ratio of the area of intima-media to the area of lumen and the ratio of thickness of intima to the thickness of media of group C were significantly lower (P < 0.05). Masson and Alcian Blue staining indicated that the remodelling of collagen and the distribution of proteoglycan in vein grafts of group C were very similar to those of the artery. Conclusion(s): The degradable vascular external sheath with slow-release bosentan can inhibit hyperplasia of intima and media and improve the shape and patency of experimental vein grafts.