The effect of platelet inhibitory therapy on graft thromboresistance

Greyhounds (n = 38) were randomized to aspirin and dipyridamole (ASA + DPM), the thromboxane synthetase inhibitor (TSI) CGS12970 (CIBA-GEIGY) or placebo twice daily for 48 hours prior to bilateral implantation of femoral artery Dacron grafts. In-vivo 111In-platelet deposition on grafts was measured at 5 days and 2 months. Grafts were removed at 2 months when ex-vivo graft and arterial release of 6-ketoprostaglandin F1a (6-keto PGF1a) was measured by radioimmunoassay. Graft 6-keto-PGF1a was significantly increased by CGS12970 but ASA + DPM had no significant effect. ASA + DPM significantly reduced arterial 6-keto-PGF1a although this was marginally increased by CGS12970. Neither active treatment reduced in-vivo 111In-platelet deposition. Preservation of vascular or graft prostacyclin by thromboxane synthetase inhibitors may represent an alternative strategy in preventing prosthetic graft thrombosis.