HEPARIN COATING OF VASCULAR PROSTHESES REDUCES THROMBOEMBOLI

Background. Synthetic conduits made from currently available materials are suboptimal for use in small-diameter vascular reconstruction beca use of their high surface thrombogenicity, which lends to failure. Met hods. In this study control, heparin-irrigated, or heparin-bonded expa nded polytetrafluoroethylene (ePTFE) grafts (4 mm long by 1 nm inner d iameter) were implanted to reconstruct the iliac artery in male rats. The cremaster muscle was isolated as an island flap based on branches of the iliac artery downstream from the graft. Emboli were quantitated by using intravital fluorescent microscopy of the cremaster muscle's microcirculation. Results. The mean number of emboli observed per anim al during a 20-minute period was 91 for the control group, 84 for the heparin-irrigated group, and 22 for the tridodecylmethylammonium chlor ide (TDMAC)-heparin group. The mean area of each embolus was 1057 mu m (2) for control, 940 mu m(2) for heparin-irrigated, and 808 mu m(2) fo r TDMAC-heparin-coated grafts (p < 0.05 for TDMAC-heparin versus contr ol or heparin-irrigated). Conclusions. A TDMAC-heparin coating of ePTF E microvascular prostheses significantly reduces downstream microembol i.