Ultrasound enhanced thrombolysis in experimental retinal vein occlusion inthe rabbit

Aims - To investigate if it was possible to lower the dose of streptokinase and maintain an effective thrombolysis by adding pulsed low energy ultraso und. Methods - 53 retinal veins in 27 rabbits were occluded by rose bengal enhan ced laser treatment. Six rabbits were treated with streptokinase (50000 IU/ kg), 10 rabbits were treated with a low dose of streptokinase (25000 IU/kg) , and 11 rabbits were treated with a low dose of streptokinase (25000 IU/kg ) and pulsed ultrasound during 1 hour, Fluorescein angiography was performe d immediately before the thrombolytic treatment and after 12 hours. Results - In the group treated with streptokinase (50000 IU/kg) all vessels were open. In the group that was given streptokinase (25000 IU/kg), 21% of the vessels were open. In the group that was treated with streptokinase (2 5000 IU/kg) and ultrasound, 64% of the vessels were open. The difference be tween groups 2 and 3 is statistically significant (p = 0.011). Conclusion - Adding pulsed low energy ultrasound makes it possible to lower the dose of streptokinase while maintaining a good thrombolytic effect.