Heparin coating of vascular prostheses reduces thromboemboli.

BACKGROUND: Synthetic conduits made from currently available materials are suboptimal for use in small-diameter vascular reconstruction because of their high surface thrombogenicity, which leads to failure. METHODS: In this study control, heparin-irrigated, or heparin-bonded expanded polytetrafluoroethylene (ePTFE) grafts (4 mm long by 1 mm inner diameter) 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 animal during a 20-minute period was 91 for the control group, 84 for the heparin-irrigated group, and 22 for the tridodecylmethylammonium chloride (TDMAC)-heparin group. The mean area of each embolus was 1057 microns 2 for control, 940 microns 2 for heparin-irrigated, and 808 microns 2 for TDMAC-heparin-coated grafts (p < 0.05 for TDMAC-heparin versus control or heparin-irrigated). CONCLUSIONS: A TDMAC-heparin coating of ePTFE microvascular prostheses significantly reduces downstream microemboli.