Healing process of a novel zero-porosity vascular graft

Abstract

We report on a study of thoracic aortic replacement in a canine model in order to demonstrate experimentally the process of tissue healing facilitated by the uniquely structured Triplex® graft. Twelve Triplex® grafts were used in this study with 12 collagen-coated vascular grafts (Hemashield®, Boston Scientific, Natick, MA, USA) as the controls in 24 dogs; the grafts were taken out 4 or 26 weeks after implantation and were analysed histopathologically. The results demonstrate, at 4 weeks after implantation, that the degree of pseudointima formation was comparable between the Triplex® grafts and the control grafts, although significant inflammatory reactivity was observed in the control grafts. After 26 weeks of implantation, significant lymphocytic infiltration was found in one animal treated with a Triplex® graft and significant neutrophil infiltration was found in one animal implanted with a control graft. In the other animals implanted with Triplex® or control grafts, the observed inflammatory reactions were similar. Specifically, in both animals implanted with Triplex® or control grafts, significant numbers of immature mesenchymal cells, fibroblasts and collagen fibres were observed at 26 weeks after implantation, and foreign-body reactions found in animals implanted with the control graft at 4 weeks after implantation were not observed at 26 weeks after implantation. Thus, the xenobiotic property and the degree of encapsulation were comparable between both the animals implanted with the Triplex® graft and those treated with the control graft. Our study demonstrated that Triplex® vascular grafts, which have a unique structure that conventional grafts do not possess, induced mild inflammation in the acute phase after the implant compared with the control grafts, and contributed to tissue healing comparable with the control graft 26 weeks after implantation.