ANTITHROMBIN AND THROMBOLYTIC EFFECTS OF A NEW ANTITHROMBIN AGENT - ANGIOSCOPIC AND ANGIOGRAPHIC COMPARISON WITH HEPARIN OR BATROXOBIN

The antithrombotic effect of three different types of antithrombotic a gents (antithrombin:argatroban, heparin, defibrinogenating agent:batro xobin) were evaluated in canine coronary and iliac arteries. An occlus ive thrombus formation (heparin 250 U/kg, argatroban 0.5 mg/kg, batrox obin 0.5 U/kg) and the effect of thrombus size reduction was evaluated . On the contralateral side of the iliac artery, the preventive effect of these agents on thrombus formation was evaluated after balloon inj ury. In the iliac artery, angioscopic percent area obstruction by the thrombus before and 60 minutes after treatment reduced from 69% to 32% in the argatroban group, and from 64% to 51% in the batroxobin group (P < 0.0001 and P < 0.05, respectively). No significant change was obs erved in the heparin group. Angiography demonstrated the same trend. T he percent area stenosis with thrombus at 60 minutes following balloon injury was 0.75% in the argatroban group, 18.9% in the heparin group (P < 0.05 vs argatroban), and 12.9% in the batroxobin group. Thrombus size at the treated site was smaller than that at the control site in all three groups (P < 0.05 vs control). In the coronary artery, angios copic percent area obstruction by the thrombus before and 60 minutes a fter treatment reduced from 84% to 53% in the argatroban group, and fr om 86% to 68% in the batroxobin group (P < 0.001 and P < 0.05, respect ively). No significant change was observed in the heparin group. Angio graphy also demonstrated the same trend. The activated partial thrombo plastin time (APTT) was prolonged to 189% of the control value with ar gatroban and to 1253% of the value with heparin (P < 0.001). Fibrinoge n was markedly reduced with batroxobin. These results showed that both the antithrombin agent and the defibrinogenating agent have a prevent ive effect on thrombus formation and the effect on thrombus size reduc tion, without marked prolongation of the APTT.