Continuous monitoring of middle cerebral artery recanalization with transcranial color-coded sonography and Levovist

Background and purpose: Treatment of acute ischemic stroke with intravenous recombinant tissue plasminogen activator (rtPA) is relatively ineffective in patients with large vessel occlusion. Numerous experimental studies have demonstrated that ultrasound (US) can accelerate enzymatic fibrinolysis and acceleration of lysis by US is enhanced in the presence of microbubbles used as echo-contrast agents. The purpose of this study was to evaluate the feasibility of continuous monitoring of middle cerebral artery (MCA) recanalization using transcranial color-coded sonography (TCCS) and intravenously administered microbubbles. Methods: Recanalization of middle cerebral artery (MCA) maintem occlusion was assessed using continuous monitoring with TCCS and intravenously administered galactose-based microbubbles (Levovist(R)) in 8 consecutive patients with acute ischemic stroke treated with intravenous rt-PA within 3 hours of symptom onset. Results: Recanalization at one hour occurred in 4 of 8 patients. The median NIHSS score was 21 (range 10 to 28) at baseline, 15 (range 0 to 24) at 1 h, and 11 (range 0 to 22) at 24 h. Asymptomatic hemorrhagic transformation (HT) was demonstrated on brain imaging in 6 patients. Conclusion: This study demonstrates the feasibility of continuous monitoring of MCA recanalization using TCCS and Levovist(R), in acute stroke patients. The findings suggest a high rate of asymptomatic HT in monitored patients. Although all HTs were asymptomatic and did not preclude early clinical improvement, particular attention should be given to the incidence and clinical significance of HT in future studies using these methods.