Introduction: Intravenous administration of recombinant tissue plasminogen activator, fastest and widely feasible treatment in acute ischemic stroke induces arterial recanalization, a prerequisite for neurological recovery. THE THERAPEUTIC ROLE OF ULTRASOUND AND POTENTIAL MECHANISM OF SONOTHROMBOLYSIS: Augmentation of recanalization can be achieved safely in combination with diagnostic transcranial Doppler by delivering mechanical pressure waves to the thrombus and exposing more thrombus surface to circulating drug. The addition of microspheres can further improve thrombolytic effect.
Clinical trials: International multicenter CLOTBUST trial showed that acute ischemic stroke patients treated with sonothrombolysis had higher rate of arterial recanalization and dramatic clinical recovery without increasing risk of symptomatic intracranial hemorrhage. A microsphere dose-escalation study called TUCSON showed that rates of recanalization and clinical recovery tended to be higher in target groups compared with controls. META-ANALYSIS OF CLINICAL TRIALS OF SONOTHROMBOLYSIS: Cochrane Stroke Group found that sonothrombolysis was likely to reduce death or dependency. A meta-analysis of sonothrombolysis showed that patients who received any form of sonothrombolysis had more than twofold higher likelihood of achieving complete arterial recanalization. PERSPECTIVES FOR SONOTHROMBOLYSIS - OPERATOR-INDEPENDENT DEVICE FOR SONOTHROMBOLYSIS: The collaborative group of the CLOTBUST trial designed multi-transducer assembly to cover conventional windows used for transcranial Doppler examinations. Operator-independent device can be quickly mounted by medical personnel with no prior experience in ultrasound. Sonothrombolysis for acute ischemic stroke is now tested in a pivotal efficacy multi-national trial called CLOTBUSTER.
Conclusion: Ultrasound is a promising tool to enhance systemic thrombolysis.