EXPANDABLE TIP ASSEMBLY FOR THROMBUS MANAGEMENT

• US 20110160757A1
• Filed: 12/29/2010
• Published: 06/30/2011
• Est. Priority Date: 10/17/2007
• Status: Abandoned Application

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Mindframe LLC (Medtronic Plc)
• Inventors: Ferrera, David, Cragg, Andrew H., Fulkerson, John, Benjamin, Joshua
• Application Number:
  US12/981,373
• Publication Number:
  US 20110160757A1
• Time in Patent Office: Days
• US Class Current: 606/159
• CPC Class Codes: A61B 17/12118 for positioning in conjunction with a stent
• CPC Class Codes: A61B 17/1214 Coils or wires
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 17/320725 with radially expandable cutting or abrading elements A61B17/32075 takes precedence
• CPC Class Codes: A61B 2017/00309 Cut-outs or slits
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/22001 Angioplasty, e.g. PCTA
• CPC Class Codes: A61B 2017/22034 for gripping the obstruction or the tissue part from inside
• CPC Class Codes: A61B 2017/22039 eccentric
• CPC Class Codes: A61B 2017/22079 with suction of debris
• CPC Class Codes: A61B 2017/22094 for crossing total occlusions, i.e. piercing
• CPC Class Codes: A61B 2017/2212 having a closed distal end, e.g. a loop
• CPC Class Codes: A61B 2017/2215 having an open distal end
• CPC Class Codes: A61B 2017/32096 for slowly cutting through tissue, e.g. stent like temporary implants having sharp edges
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61M 2025/0042 Microcatheters, cannula or the like having outside diameters around 1 mm or less
• CPC Class Codes: A61M 25/0074 Dynamic characteristics of the catheter tip, e.g. openable, closable, expandable or deformable

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 comprise a three-step progressive treatment process that includes 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 and maceration. The progressive, or modular, treatment can be provided by a system or kit of one or more treatment devices.

Claims

1. An expandable tip assembly, comprising:

an elongate member;

a self-expanding scaffold coupled to a distal end of the elongate member, the scaffold being adapted to radially expand from a non-expanded configuration to an expanded configuration and adapted to transition from the expanded configuration to the non-expanded configuration upon 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,

wherein each bridge is connected to four struts;

wherein the struts and the bridges have varying thickness to impart flexibility to the scaffold;

wherein the scaffold has a chronic outward force (COF) per unit length that does not decrease by more than 75% from a diameter of 1.5 mm to a diameter of 4.5 mm; and

wherein the open cells have a cell size of about 5 mm by about 3 mm.

2. The expandable tip assembly of claim 1, wherein the scaffold has a chronic outward force (COF) per unit length that does not decrease by more than 50% from a diameter of 1.5 mm to a diameter of 4.5 mm.

3. The expandable tip assembly of claim 1, wherein a central portion of each strut has a greater thickness than adjacent portions of the strut.

4. The expandable tip assembly of claim 1, wherein a central portion of each strut has a greater width than adjacent portions of the strut.

5. The expandable tip assembly of claim 1, wherein the scaffold comprises nitinol.

6. The expandable tip assembly of claim 1, wherein the elongate member comprises a stainless steel hypotube.

7. The expandable tip assembly of claim 1, wherein the elongate member comprises a guidewire.

8. An expandable tip assembly, comprising:

an elongate member;

a self-expanding scaffold coupled to a distal end of the elongate member, the scaffold being adapted to radially expand from a non-expanded configuration to an expanded configuration and adapted to move from the expanded configuration to the non-expanded configuration upon sheathing of the scaffold;

wherein the scaffold comprises a plurality of open cells defined by struts and connected by bridges;

wherein the open cells have a cell size of about 3 mm by about 1.25 mm; and

wherein the scaffold has a an average chronic outward force (COF) per unit length across a diameter of 2.0 mm to 4.5 mm of between at least about 0.00165 N/mm and at least about 0.0090 N/mm.

9. The expandable tip assembly of claim 8, wherein the scaffold comprises nitinol.

10. The expandable tip assembly of claim 8, wherein the elongate member comprises a stainless steel hypotube.

11. The expandable tip assembly of claim 8, wherein the elongate member comprises a guidewire.

12. An expandable tip assembly, comprising:

a variable-stiffness, laser-cut hypotube having a lumen sized and adapted to receive a guidewire, a distal end of the hypotube having a greater flexibility than the proximal end to facilitate introduction within tortuous cerebral vasculature;

an expandable and reconstrainable scaffold coupled to a distal end of the hypotube, the scaffold being adapted to radially self-expand from a non-expanded configuration to an expanded configuration and adapted to move from the expanded configuration to the non-expanded configuration upon sheathing of the scaffold;

wherein the scaffold comprises a generally cylindrical configuration;

wherein the scaffold comprises a plurality of open cells defined by struts and connected by bridges;

wherein each strut of the scaffold has a strut width and a strut thickness providing effective pinching stiffness and hoop stiffness for compressing a vascular clot to promote at least one of lysis, maceration, and removal of the clot without compromising trackability of the stroke device.

13. The expandable tip assembly of claim 12, wherein the scaffold has an average chronic outward force (COF) per unit length across a diameter of 2.0 mm to 4.5 mm of between at least about 0.0025 N/mm and at least about 0.007 N/mm.

14. The expandable tip assembly of claim 12, wherein the scaffold has an average COF per unit length across a diameter of 2.0 mm to 4.5 mm of between at least about 0.0030 N/mm and at least about 0.0059 N/mm.

15. The expandable tip assembly of claim 12, wherein the scaffold has a COF range per unit length across a diameter of 2.0 mm to 4.5 mm of between at least about 0.00165 N/mm and at least about 0.0090 N/mm.

16. The expandable tip assembly of claim 12, wherein the scaffold has a radial resistive force (RRF) range per unit length across a diameter of 2.0 mm to 4.5 mm of between at least about 0.005 N/mm and at least about 0.016 N/mm.

17. The expandable tip assembly of claim 12, wherein the ratio of strut thickness to strut width is less than at least about 1.4.

18. The expandable tip assembly of claim 12, wherein the strut thickness is substantially equal to the strut width.

19. The expandable tip assembly of claim 12, wherein the struts of the scaffold have a pointed or tapered configuration to facilitate engagement of the thrombus.

20. The expandable tip assembly of claim 12, wherein the cell size of the scaffold is variable along the length of the scaffold, and further wherein the cell size of the cells at the end portions of the scaffold are smaller than the cell size of the cells of the middle portion of the scaffold.