Robotic Ultrasound-Mediated Thrombectomy for First Pass Stroke Treatment - Greater than 80,000 people in the U.S. suffer from large vessel occlusive (LVO) stroke each year. LVOs are responsible for the majority of disability, death, and costs associated with acute ischemic stroke. Endovascular mechanical thrombectomy, i.e., physical extraction of the clot with endovascular retrieval devices or “stentrievers” has been demonstrated to provide superior clinical outcomes relative to other treatments. However, despite the clear benefits of this approach demonstrated in multiple clinical trials, in most patients (75%), the first attempt is unsuccessful, leading to multiple repeated attempts. As the number of “passes” increases, patient quality of life decreases, i.e., 75% of patients successfully treated on the first attempt have favorable clinical outcomes compared to just 35% of patients with favorable outcomes for those requiring multiple attempts. The overarching goal of this project is effective restoration of blood flow to the brain while avoiding acute injury and distal embolization. The central objective of this project is to develop a robotically-delivered therapeutic ultrasound (US) system for safe, effective recanalization in acute LVO stroke and to test this system in clots in patient-specific, 3D-printed phantoms, determine ultrasound and delivery conditions resulting in injury, and test in an animal model. Thus, three specific aims will be addressed in this project: SA1 (GT-Lindsey): Rapid ultrasound (US) therapy and monitoring. Develop a 2 mm device (improving on previous 3 mm devices) to ensure rapid dissolution of clots in the internal carotid artery (ICA) terminus and proximal middle cerebral artery (MCA). Stentriever-based imaging will monitor therapy and guide treatment. 3D- printed phantoms based on de-identified CT scans of patients will be used to test the developed system. SA2 (GT-Desai): Effective delivery of US and aspiration. Develop a modular coaxially aligned steerable (M- COAST) system to deliver US and aspiration / irrigation devices to the ICA / MCA. Rigorous device testing will be performed through 3D-printed phantom studies based on de-identified CT scans of patients. SA3 (Emory and GT): Determine acoustic pulse parameters, compare developed system with current standard in animal model. Acoustic pulse parameters and delivery conditions sufficient for clot dissolution while minimizing injury to the ICA/MCA will be determined via simulations and experiments. Risk indices will be developed prior to proceeding to testing to compare the developed system with current thrombectomy devices in a pig model. In vivo evaluation criteria include vessel injury, dissolution efficacy, procedure duration, number of passes, reperfusion status, distal embolization, and percent flow restored. This project combines expertise in ultrasound, steerable systems, and stroke neurosurgery. The proposed technology will directly impact 41.3% of patients with MCA and ICA occlusions who are currently untreatable with existing devices. There is a critical need for new technology in endovascular LVO treatment - see attached letters of support from Dr. Kan (UTMB), Dr. Mack (USC), and Dr. Jayaraman (Brown University).
