Comparison of antithrombotic activity of heparin, ASA, sulfinpyrazone and VK 744 in a rat model of arterial thrombosis.

Rat carotid arteries were injured electrically (350 V, 2 mA DC for 5 min) before and after the intravenous administration of heparin (1,000 U/kg), VK 744 (25, 50, 100 mg/kg) ASA (100, 200 mg/kg) and sulfinpyrazone (50, 100, 150, 200 mg/kg). Thrombus growth was quantified by recording arterial temperature change distal to the injury. Heparin completely blocked thrombus formation in most experiments. All other agents exhibited antithrombotic activity with sulfinpyrazone being most potent. None was as effective as heparin. This model may be a useful tool for screening antithrombotic drugs.