Experimental canine arterial thrombus formation and thrombolysis: a fiberoptic study

We produced arterial thrombi that simulated the clinical condition in canine iliac arteries by endothelial denudation and partial occlusion. The processes of thrombus formation and thrombolysis were examined by vascular fiberscope. Laminar mural thrombi developed in all 21 preparations 10 minutes after blood reperfusion, with stenosis formation. Over 50% luminal obstruction with thrombi occurred in 10 preparations 30 minutes after inducing stenosis. Total occlusion with thrombi occurred in four preparation (31%) at 1 hour, and in all nine at 3 hours after inducing stenosis. Usually, red thrombus at the denudated region grew in size distal to the sited of stenosis. Histologically, thrombi of less than 1 hour duration consisted of a loose fibrin network and those of over 3 hours' duration consisted of a dense fibrin network. Infusion of 144,000 IU of urokinase (UK) reduced the size of thrombi less than 1 hour old during fiberoptic observation. However, UK infusion of similar dose failed to recanalize two of four preparations with 3-hour-old thrombi. In conclusion, arterial thrombi that closely simulate those observed clinically can be made by endothelial denudation and partial occlusion, and the vascular fiberscope provides a useful method for analysis of thrombosis and thrombolysis.