THROMBUS MANAGEMENT DEVICE
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.
1 . An expandable tip assembly configured to address an occlusive thrombus within a blood vessel without distal embolic protection, comprising:
an elongate member;
an expandable and reconstrainable scaffold coupled to the distal end of the elongate member, the scaffold being 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 scaffold;
wherein the scaffold comprises a laser-cut tube;
wherein the scaffold is coupled to the distal end of the elongate member by a plurality of tether lines;
wherein the scaffold comprises an open distal end without a distal embolic protection member or device;
wherein a proximal end of the scaffold comprises a scooped-out section configured to facilitate re-sheathing of the scaffold;
wherein the scaffold comprises a plurality of open cells defined by struts and connected by bridges;
wherein each strut has two ends, with each end connected to one of the bridges; and
wherein the open cells are sized to promote at least one of vessel reperfusion or thrombus removal.
2 . The expandable tip assembly of claim 1 , wherein the elongate member is a wire.
3 . The expandable tip assembly of claim 1 , wherein the elongate member is a hypotube having variable stiffness along its length.
4 . The expandable tip assembly of claim 1 , wherein the scaffold is eccentrically coupled to the distal end of the elongate member with the plurality of tether lines to facilitate resheathing into an outer catheter and increase blood flow through the scaffold.
5 . The expandable tip assembly of claim 1 , wherein the scaffold has variable cell size.
6 . The expandable tip assembly of claim 1 , wherein the scaffold comprises a generally cylindrical body having a length configured to at least partially span the thrombus and a sufficient radial force to provide continuous radial expansion as the thrombus is lysed.
7 . The expandable tip assembly of claim 6 , wherein the plurality of tether lines extend from less than half of the circumference of a proximal end of the generally cylindrical body.
8 . The expandable tip assembly of claim 1 , wherein the cells of the scaffold have a cell length of between 4 mm and 6 mm and a cell height between 2 mm and 4 mm in the expanded configuration.
9 . The expandable tip assembly of claim 1 , wherein the 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.
10 . The expandable tip assembly of claim 1 , wherein the struts comprise one or more surface features adapted to enhance engagement of thrombus material.
11 . The expandable tip assembly of claim 10 , wherein the surface features comprise one or more grooves or one or more protrusions or projections.
12 . The expandable tip assembly of claim 1 , wherein a central portion of each strut of the scaffold has a greater thickness than adjacent portions of the strut.
13 . The expandable tip assembly of claim 1 , wherein the struts comprise multiple flex points along the length of the struts.
14 . The expandable tip assembly of claim 1 , wherein the bridges form X-shaped connections between the cells of the scaffold.
15 . The expandable tip assembly of claim 1 , wherein the bridges have a greater thickness than adjacent portions of the struts connected to the bridges.
16 . The expandable tip assembly of claim 1 , wherein the scaffold comprises an open, tapered proximal end with a cut-out or everted section.
17 . The expandable tip assembly of claim 1 , wherein the scaffold is permanently, non-removably coupled to the elongate member.
18 . The expandable tip assembly of claim 1 , wherein the scaffold is detachably coupled to the elongate member.
19 . The expandable tip assembly of claim 1 , wherein the scaffold has a maximum expansion diameter of about 1 mm to about 5 mm.
20 . The expandable tip assembly of claim 1 , wherein the scaffold has a length of about from about 5 mm to about 50 mm.
21 . The expandable tip assembly of claim 1 , wherein the scaffold comprises one or more of the following features:
a tapered body;
a coating configured to increase platelet activation or adhesion of the thrombus to the scaffold;
strut thickness that is substantially the same as the strut width;
does not comprise a backbone; and
is not a rolled mesh scaffold that is configured to overlap on itself.
22 . The expandable tip assembly of claim 1 , wherein the scaffold comprises one or more of the following features:
a body having a triangular, elliptical, spiral or undulating configuration;
a non-thrombogenic coating or a coating with an anti-clotting drug;
a ratio of strut thickness to strut width is less than at least about 1.4;
parallelogram-shaped cells; and
U-shaped bridges between cells of the scaffold.