Effects of local irrigation and intravenous administration of human tissue-type plasminogen activator on microvascular thrombosis

ABSTRACT

intravenous administration of human tissue-type plasminogen activator (t-PA). Nine rabbits weighing about 2 kg were used. After exposure of both femoral veins, the veins were crushed by the jaws of smooth needle holder in order to create a thrombosis model. Transectional incision was made in the vein. The animals were then divided into 3 groups 1) Experimental Group I, topical irrigation of lumen with t-PA saline solution (n=6); 2) Experimental Group 2, Intravenous administration of t-PA (0.75 mg/kg) via the marginal ear vein for 3 days; 3) Control Group, topical irrigation of lumen with saline solution (n=6). The patency was evaluated with empty-and-refill test and thrombus formation was judged by surgical microscope. The histologic findings were also evaluated. Thirty minutes after microvascular anastomosis, the patency of all Experimental Groups 1 and 2 was more improved than that of Control Group. However, there was no significant difference among groups. Three days after microvascular anastomosis, the patency of all Experimental Groups was much more improved than that of Control Group (P<0.05). There was no significant difference between Experiment Group 1 and Experiment Group 2. Three days after microvascular anastomosis, the amount of thrombus in all Experimental Groups was much less than that of Control Group (P<0.05). In histologic findings, a lot of luminal thrombus were observed around sutured area in Control Group. Few luminal thrombus was observed in all Experimental Groups. The necrotic changes were was observed in the vessel wall of all specimens. These results indicate that topical irrigation and intravenous administration of t-PA are effective measures in improving patency and preventing thrombus formation after microvascular anast omosis.