Faculty Member Islamic Azad University- Tabriz Branch Tabriz, Azarbayjan-e Sharqi, Iran
Background: The efficacy of intravenous thrombolytic agent tissue plasminogen activator (tPA) is limited owing to a relatively poor recanalization rate and incomplete function recovery in the majority of treated patients.
Aims: In this study, we developed an experimental triple- frequency ultrasonic wave generator, and investigate its effectiveness on the thrombus reduction in the rabbit common carotid artery, in combination with intravenous tPA administration.
Methods: Male New Zealand white rabbits were submitted to common carotid artery clot embolism. Then treatment group underwent triple- frequency focused ultrasound therapy (F= 150 KHz, F= 750 KHz, F= 1.1 MHz, Iave= 12W/cm2) accompanied by tPA administration, wherein diagnostic B- mode ultrasound is combined with therapy system, with a goal of increased safety. Blood volume flow and blood mean velocity were measured by color Doppler ultrasonography. Moreover, percentage of luminal cross-sectional area of stenosis were measured by B-mode ultrasound at the occluded region after treatment.
Results: Results showed a significant reduction in the mean value for blood mean velocity and the percentage of luminal cross-sectional area of stenosis and a significant increase in the mean value for blood volume flow in the treatment group compared with the other groups (P < 0.05).
Conclusion(s): Enhanced anti- thrombotic effect of tPA- induced by sonoporation effect of ultrasonic waves, accompanied by enhanced anti- thrombotic effect of inertial cavitation- based collapsed bubbles (microstreaming, microjet, shock wave)- induced by triple frequency transducer, can cause to reduce the thrombus content and significantly dilate the luminal cross-sectional area of stenosis. Combined triple frequency ultrasound and tPA thrombolytic therapy may be an effective potential treatment for embolism.
