Prototype therapeutic ultrasound emitting catheter for accelerating thrombolysis.

The aim of this study was to evaluate the performance of a new therapeutic ultrasound device for accelerating thrombolysis by urokinase. Artificial thrombi were produced in vitro by Chandler's loop method. Urokinase (240 IU) was added to the artificial thrombi (n = 5) before exposure to ultrasound with the new catheter-delivered device. Ultrasound (1.3 MHz) was applied with an intensity of 0.3 W/cm2 for 60 s. The degree of fibrinolysis was obtained by measurement of thrombus weight and calculated as percentages. Fibrinolysis was compared between control thrombus groups (n = 5) treated with urokinase alone or with ultrasound alone (analysis of variance, P < 0.05). Ultrasound plus urokinase (33.1 +/- 6.1% [mean +/- standard deviation]) was significantly different urokinase alone (12.3 +/- 2.4%) after 15 min of incubation. Ultrasound alone resulted in no fibrinolysis (0.9 +/- 2.5%). Ultrasound energy from the catheter-based device was sufficient to induce acceleration of fibrinolysis with urokinase.