A novel clot containing system for improved neurothrombectomy outcomes

PROJECT SUMMARY Mechanical thrombectomy (MT) has recently gained impetus as a treatment for acute ischemic stroke (AIS). Although technical progress has been made, the efficacy of the current techniques remains sub-optimal and MT is still associated with significant complications. Current MT techniques, using stent retrievers or aspiration catheters, achieve successful revascularization after the first-pass only in less than 50% of the patients irrespective of the technique used. Further embolic complications, which occur in 10-20% of cases, cause significant sequelae. Xtract Medical is developing a patent-protected accessory device, which is a novel Clot Containment System (CCS) that consists of an expandable nitinol braided tube on the end of a guidewire that is delivered through existing neurovascular aspiration or guide catheters. The braid is covered with a thin silicone coating, which blocks the blood flow when it extends out of the distal end of the delivery catheter and additionally provides complete enclosure of the clot during extraction from the patient. At the front of the braid, a closure wire weaves through the loops in the braid and then connects to the guidewire that runs the length of the catheter and out of the patient. This closure wire acts as a snare so that when the closure wire is actuated by the surgeon the front end of the braid cinches like a purse string. Xtract Medical’s solution will improve the efficacy of MT procedure in three fundamental ways: 1) Its deployment leads to local blood flow arrest in the Middle Cerebral Artery (MCA). This will enhance the aspiration forces when it is combined with an aspiration catheter and, regardless of the applied MT method, reduce distal migration and fragmentation of the clot. 2) Gentle expansion of the device in the cerebral artery proximal to the clot creates a larger lumen size for the clot to be trapped into, increasing the likelihood of the entire clot removal by the aspiration catheter or stent retriever in the first pass. 3) Through its unique closure system, the device completely contains the blood clot during its retrieval from the brain, preventing the release of clot fragments and reducing embolic complications. In this SBIR Phase I project, Xtract Medical will conduct pivotal benchtop studies and pre-clinical validation of the efficacy and safety of its accessory device. Phase I (9 months) is a feasibility study during which the prototype will undergo further development and validation in a benchtop model of neurovasculature (Aim 1) as well as a preliminary evaluation of efficacy and safety in vivo in swine models (Aim 2). After completion of Phase I, Xtract Medical will propose a Phase II SBIR project for the establishment of a quality system and validation testing of the design and completion of pivotal pre-clinical GLP in vivo studies, which will lay the foundation for Xtract Medical to pursue FDA clearance of its device, as well as to establish a pathway for the commercial launch of their device.PROJECT NARRATIVE Stroke is the 5th most common cause of death in the US and the leading cause of disability with an estimated direct and indirect cost amounting to more than $100 billion each year. Current procedures of mechanical thrombectomy, an endovascular procedure to restore the blood flow after ischemic stroke, can cause clot fragmentation during removal, and often necessitate two or more passes to achieve complete revascularization. The proposed device will be the first accessory device for catheters that completely contains the blood clot during removal from the patient and improves first-pass efficiency, thereby improving the patient’s functional outcome.