Thrombectomy devices and treatment of acute ischemic stroke with thrombus engagement
Components and corresponding systems are described for providing removal of a clot or fragment thereof to address an acute ischemic stroke condition. In particular, a filter design is presented that provides metal elements below a bundle of polymer fibers to provide more mechanical strength while cushioning the vessel wall from direct contact with the metal elements. Designs of stent retrievers are presented with polymer covers or mounted on the exterior of a microcatheter. Corresponding systems are described that can use various combinations of the components, generally in combination with an aspiration catheter. Corresponding procedures are described that can effectively use the various devices and systems.
1. A filter device having an un-deployed low profile configuration and an unconstrained deployed configuration comprising a guide structure, an anchor secured at a fixed location on the guide structure having a central axis, a slide positioned over the guide structure, a filter cartridge secured on one end to the anchor and on the other end to the slide, wherein the filter cartridge comprises a plurality of unwoven polymer fibers in a bundle in the un-deployed low profile configuration, and one or more metal elements radially below relative to the central axis of the bundle of polymer fibers secured around the guide structure, wherein moving the slide closer to the anchor transitions the metal elements to the unconstrained deployed configuration with the metal elements forming a curved structure extending radially outward, wherein the device in the unconstrained deployed configuration further comprises the furthest radial extent of the metal elements being below a mat of fibers, and wherein the metal elements have an unconstrained radial extent no more than about 94% of the furthest unconstrained radial extent of the polymer fibers.
2. The filter device of claim 1 wherein the metal elements comprise three or more unbraided elements.
3. The filter device of claim 1 wherein metal elements comprise braided wires.
4. The filter device of claim 1 wherein the metal elements comprise three to ten elements with a circumference from about 0.0005 inches (12 microns) to about 0.025 inches (600 microns).
5. The filter device of claim 1 wherein the filter cartridge further comprises metal wires in the bundle with the polymer fibers from about 1% to about 10% of the number of strands being metal wire and having a diameter from about 0.0001 inches (2.4 microns) to about 0.002 inches (48 microns).
6. The filter device of claim 1 wherein the filter cartridge is self actuating, wherein the metal elements comprise a spring metal with a shape memory that assumes a pre-selected shape upon release of constraint of the filter cartridge.
7. The filter device of claim 1 further comprising an overtube connected to the slide and extending in a proximal direction over the guide structure, wherein relative movement of the overtube and the guide structure transitions the filter cartridge from the un-deployed low profile configuration to the unconstrained deployed configuration, wherein the filter cartridge extends radially.
8. The filter device of claim 7 wherein the overtube comprises a polymer tube.
9. The filter device of claim 1 wherein the metal elements have an unconstrained radial extent no more than about 90% of the furthest unconstrained radial extent of the polymer fibers.
10. The filter device of claim 1 wherein the polymer fibers comprise polyamides (e.g., nylon), polyesters (e.g., polyethylene terephthalate), polyacetals/polyketals, polyimide, polystyrenes, polyacrylates, vinyl polymers (e.g., polyethylene, polytetrafluoroethylene, polypropylene and polyvinyl chloride), polycarbonates, poly dimethyl siloxanes, cellulose acetates, polymethyl methacrylates, polyether ether ketones (PEEK), ethylene vinyl acetates, polysulfones, nitrocelluloses, similar copolymers and mixtures thereof.
11. The filter device of claim 1 wherein the metal wires are radiopaque.
12. The filter device of claim 1 wherein the metal wires extend into a curved structure.
13. The filter device of claim 12 wherein the extended curved metal wires form petal shaped features around an open interior.