Expanded polytetrafluoroethylene (ePTFE) vascular graft loses its thrombogenicity six months after implantation

Although expanded polytetrafluoroethylene (ePTFE) has been believed to be an inert material for vascular prosthesis, it shows less tendency of graft maturation by means of endothelialization. The aim of this study is to evaluate long-term alteration in thrombogenicity of ePTFE grafts after implantation. Serial levels of thrombin-antithrombin III complex (TAT), D-dimer, C-reactive protein (CRP), and prothrombin time (PT) were examined in 77 patients following ePTFE Y-graft implantation for up to five years. TAT showed biphasic elevation after implantation; TAT increased from 16.4+/-8.6 ng/ml to 27.4+/-10.5 ng/ml at one day, decreased to 18.5+/-4.5 ng/ml at one week, and increased again to 25.3+/-8.5 ng/ml at two weeks. Elevated TAT gradually decreased after the second peak to reach a lower level than that before surgery after six months. There was no significant difference in TAT level after six months due to the difference in diagnosis or anti-thrombotic therapy. We suggest that ePTFE grafts lose their thrombogenicity six months after implantation, after which anti-thrombotic therapy might be unnecessary.