Thrombus management system

Abstract

Systems, methods, and devices for the treatment of acute ischemic stroke that provide immediate blood flow restoration to a vessel occluded by a clot and, after reestablishing blood flow, address the clot itself. Immediate blood flow restoration advantageously can facilitate natural lysis of the clot and also can reduce or obviate the concern for distal embolization due to fragmentation of the clot. Several embodiments of the invention provide for progressive, or modular, treatment based upon the nature of the clot. For example, the progressive treatment can include immediate restoration of blood flow, in-situ clot management, and/or clot removal depending on the particular circumstances of the treatment. The in-situ clot management can include, for example, lysis, maceration, and/or removal.

What is claimed is: 
     
         1 . A system comprising a plurality of expandable tip assemblies configured to address an occlusive thrombus within a blood vessel for providing progressive therapy without distal embolic protection, the system comprising:
 a first expandable tip assembly comprising a first elongate member and a first self-expanding scaffold;   wherein the first self-expanding scaffold is coupled to a distal end of the first elongate member;   wherein the first self-expanding scaffold comprises an open distal end without a distal embolic protection member or device;   wherein the first self-expanding scaffold comprises open cells formed by a pattern of struts and bridges, wherein said cells have a cell size configured to hinder penetration of thrombus material within the first self-expanding scaffold, thereby increasing an amount of blood flow through the first self-expanding scaffold; and   a second expandable tip assembly comprising a second elongate member and a second self-expanding scaffold;   wherein the second self-expanding scaffold is coupled to a distal end of the second elongate member;   wherein the second self-expanding scaffold comprises an open distal end without a distal embolic protection member or device;   wherein the second self-expanding scaffold comprises open cells formed by a pattern of struts and bridges, wherein said cells have a cell size larger than the cell size of the first self-expanding scaffold, wherein said cell size of the second self-expanding scaffold is configured to enhance penetration of thrombus material within the scaffold to facilitate capture of the thrombus;   wherein, in use, the first self-expanding scaffold and the second self-expanding scaffold are adapted to radially self-expand from a non-expanded configuration to an expanded configuration and to transition from the expanded configuration to the non-expanded configuration upon unsheathing and re-sheathing of the first and second self-expanding scaffolds.   
     
     
         2 . The system of  claim 1 , further comprising a microcatheter adapted to receive the first and second self-expanding scaffolds and further adapted to be movable with respect to the first and second self-expanding scaffolds to provide the unsheathing and re-sheathing of the first and second self-expanding scaffolds. 
     
     
         3 . The system of  claim 1 , wherein each of the first elongate member and the second elongate member is a variable-stiffness hypotube having a lumen. 
     
     
         4 . The system of  claim 3 , further comprising a guidewire configured to be received by the first elongate member and the second elongate member. 
     
     
         5 . The system of  claim 3 , wherein a distal section of the variable-stiffness hypotube comprises a laser spiral cut pattern that allows the distal section to bend to navigate through curved portions of the cerebral vasculature. 
     
     
         6 . The system of  claim 5 , wherein said laser spiral cut pattern spans a length of about 35 cm. 
     
     
         7 . The system of  claim 1 , wherein each of the first elongate member and the second elongate member is a wire without a lumen. 
     
     
         8 . The system of  claim 1 , wherein the first expandable tip assembly and the second expandable tip assembly have an average chronic outward force across a diameter of 1.5 mm to 4.5 mm that does not decrease by more than 90%. 
     
     
         9 . The system of  claim 1 , wherein the first self-expanding scaffold and the second self-expanding scaffold have a substantially non-zero chronic outward force across a diameter of 1.5 mm to 4.5 mm. 
     
     
         10 . The system of  claim 1 , wherein the cells of the first self-expanding scaffold have a cell length of between 2 mm and 4 mm and a cell height between 1 mm and 3 mm in an expanded configuration. 
     
     
         11 . The system of  claim 1 , wherein the first self-expanding scaffold has an average chronic outward force across a diameter of 1.5 mm to 4.5 mm of between 0.0040 N and 0.0120 N. 
     
     
         12 . The system of  claim 1 , wherein the cells of the second self-expanding scaffold have a cell length of between 4 mm and 6 mm and a cell height between 2 mm and 4 mm in an expanded configuration. 
     
     
         13 . The system of  claim 1 , wherein the second self-expanding scaffold has an average chronic outward force across a diameter of 1.5 mm to 4.5 mm of between 0.0020 N and 0.0090 N. 
     
     
         14 . The system of  claim 1 , wherein a central portion of each strut of the second self-expanding scaffold has a greater thickness than adjacent portions of the strut. 
     
     
         15 . The system of  claim 1 , wherein the first expandable tip assembly comprises a reperfusion device adapted to facilitate blood flow restoration and the second expandable tip assembly comprises a thrombus removal device adapted to be inserted after removal of the reperfusion device, wherein the thrombus removal device is further adapted to facilitate removal of any remaining thrombus material. 
     
     
         16 . The system of  claim 1 , wherein the first self-expanding scaffold is eccentrically coupled to the distal end of the first elongate member with a plurality of tether lines and wherein the second self-expanding scaffold is eccentrically coupled to the distal end of the second elongate member with a plurality of tether lines. 
     
     
         17 . The system of  claim 1 , wherein the first self-expanding scaffold and the second self-expanding scaffold comprise generally cylindrical bodies. 
     
     
         18 . The system of  claim 17 , wherein the plurality of tether lines extend from less than half of the circumference of a proximal end of the generally cylindrical body of each of the first and second self-expanding scaffolds. 
     
     
         19 . The system of  claim 1 , wherein each of the first self-expanding scaffold and the second self-expanding scaffold comprises a rolled scaffold. 
     
     
         20 . The system of  claim 1 , wherein the first self-expanding scaffold is permanently, non-removably coupled to the first elongate member and/or wherein the second self-expanding scaffold is permanently, non-removably coupled to the second elongate member. 
     
     
         21 . The system of  claim 1 , wherein the first self-expanding scaffold is detachably coupled to the first elongate member and/or wherein the second self-expanding scaffold is detachably coupled to the second elongate member. 
     
     
         22 . The system of  claim 1 , wherein each of the first self-expanding scaffold and the second self-expanding scaffold has a maximum expansion diameter of about 1 mm to about 5 mm. 
     
     
         23 . The system of  claim 1 , wherein each of the first self-expanding scaffold and the second self-expanding scaffold has a length of about from about 5 mm to about 50 mm. 
     
     
         24 . The system of  claim 1 , wherein each of the first and second self-expanding scaffolds comprises one or more of the following features:
 a coating configured to increase platelet activation or adhesion of the thrombus to the scaffold;   parallelogram-shaped cells;   cells having a uniform cell size;   U-shaped bridges between cells;   does not comprise a backbone; and   formed from a laser-cut tube.   
     
     
         25 . The system of  claim 1 , wherein each of the first and second self-expanding scaffolds comprises one or more of the following features:
 an open, tapered proximal end configured to facilitate resheathing into an outer catheter and increase blood flow through the scaffold;   cells having variable cell size;   X-shaped bridges between cells;   a body having a triangular, elliptical, spiral or undulating configuration;   a non-thrombogenic coating or a coating with an anti-clotting drug; and   is not a rolled mesh scaffold that is configured to overlap on itself