Iloprost in alginate decreases the thrombogenicity of expanded polytetrafluoroethylene

Vascular prostheses of small diameter perform poorly in vivo, in part because of the high thrombogenicity of available biomaterials. This study examined the thrombogenicity of expanded polytetrafluoroethylene (ePTFE) vascular graft segments (10 mm long x 4 mm i.d.) in vitro before and after impregnation with saline, alginate, or alginate containing the stable prostacyclin analog, iloprost. Each segment was immersed in activated whole blood and the weight of the adherent thrombus was measured at specified intervals. At 6 and 7 min the saline-denucleated group accumulated significantly less thrombus than control (p < .05). Alginate alone was not significantly different from controls. The graft segments treated with alginate + iloprost accumulated significantly less thrombus (p < .05) than all other groups after 6 min. These data demonstrate that denucleation of ePTFE with iloprost in alginate dramatically decreases its in vitro thrombogenicity.