Intraarterial thrombolysis in a pig model: a preliminary note

To develop a pig model of arterial thrombosis suitable for assessing different methods of thrombolysis and to use this model to compare the efficacy of intraarterial thrombolysis performed by continuous proximal urokinase infusion versus mechanical clot disruption combined with intrathrombic urokinase injection.

In a control group of five pigs, a thrombus was made in a short segment of femoral artery and observed for 2 hours to assess its stability. In a treatment group of six pigs, intraarterial thrombolysis was performed immediately after thrombus formation. Thrombolysis was accomplished by continuously infusing urokinase into the proximal leading edge of the thrombus in three pigs and by mechanical clot disruption combined with intrathrombic urokinase injection in the remaining three pigs.

There was no spontaneous reestablishment of flow in the control group during the 2-hour observation period. In the first treatment group, no flow was observed after a 1-hour treatment period when urokinase was infused continuously into the proximal edge of the thrombus. In the second treatment group, with mechanical clot disruption and intrathrombic urokinase injection, some degree of flow was observed in all three pigs. Reestablishment of flow was more sustained and of a greater degree with the addition of systemic heparinization.

This animal model could provide a useful way to evaluate and compare different methods of thrombolysis. Our results suggest that mechanical clot disruption combined with intrathrombic urokinase injection is more effective in achieving reestablishment of flow than is continuous infusion of urokinase into the proximal edge of the thrombus.