Some effects of prophylactic aspirins and heparins on concurrent arterial and venous thrombosis in the same animal.

The antithrombotic effect of unfractionated heparin, a low-molecular weight heparin, oral acetylsalicylic acid, intravenous lysine-aspirin and oral soluble aspirin was measured on platinum wire simultaneously in artery and vein, in groups of 12-20 rats with concurrent untreated controls. Subcutaneous low molecular weight heparin reduced mean thrombus weight by 26% in the artery only. Venous thrombosis was reduced 56% by oral soluble acetylsalicylic acid and 27% by oral aspirin. Other reductions did not reach statistical significance. While thrombus deposition was induced by both 2-cm (upper site) and 1-cm (lower site) wires, the results obtained on the 2-cm wires in the upper vein and artery were more reliable [corrected].