Expandable tip assembly for thrombus management

• US 8,945,143 B2
• Filed: 06/24/2013
• Issued: 02/03/2015
• Est. Priority Date: 10/17/2007
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Ferrera, David A., Cragg, Andrew H., Fulkerson, John
• Primary Examiner(s): FISHBACK, ASHLEY LAUREN
• Application Number:
  US13/924,703
• Publication Number:
  US 20140155981A1
• Time in Patent Office: 589 Days
• Field of Search: 604/93.01, 604/96.01, 604/507, 606/127, 606/191, 606/192, 606/194, 606/200, 623/1.1, 623/1.12, 623/1.15, 623/1.16, 623/1.36, 623/1.39, 623/1.4
• US Class Current: 606/127
• CPC Class Codes: A61B 17/22031 Gripping instruments, e.g. forceps, for removing or smashing calculi A61B17/221 takes precedence
• 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 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/22038 with a guide wire
• CPC Class Codes: A61F 2/01 Filters implantable into blood vessels
• 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 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2002/016 made from wire-like elements
• CPC Class Codes: A61F 2002/018 made from tubes or sheets of material, e.g. by etching or laser-cutting
• CPC Class Codes: A61F 2230/0006 circular
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2230/0091 helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2230/0093 Umbrella-shaped, e.g. mushroom-shaped
• CPC Class Codes: A61F 2230/0097 Harpoon-shaped

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.

Claims

1. An expandable tip assembly adapted to address an occlusive thrombus within a blood vessel, comprising:

an elongate member;

a tubular scaffold coupled to a distal end of the elongate member, the scaffold comprising a plurality of cells and configured to radially self-expand from a non-expanded configuration within a catheter to an expanded configuration upon unsheathing of the scaffold from the catheter;

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

3. The expandable tip assembly of claim 1, wherein the scaffold is coupled to the distal end of the elongate member by a plurality of tethers that extend eccentrically from the distal end of the elongate member.

4. 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.

5. The expandable tip assembly of claim 1, wherein the cells of the scaffold have a uniform cell size.

6. The expandable tip assembly of claim 1, wherein the cells of the scaffold have a variable cell size.

7. The expandable tip assembly of claim 1, wherein the cells of the scaffold have a cell size adapted to inhibit protrusion of portions of the thrombus within an interior of the scaffold.

8. The expandable tip assembly of claim 1, wherein the cells of the scaffold have a cell size adapted to promote protrusion of portions of the thrombus within an interior of the scaffold.

9. 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.

10. 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.

11. The expandable tip assembly of claim 1, wherein the scaffold is permanently, non-removably coupled to the elongate member.

12. The expandable tip assembly of claim 1, wherein the scaffold is detachably coupled to the elongate member.

13. The expandable tip assembly of claim 1, wherein a proximal end of the scaffold is open.

14. The expandable tip assembly of claim 1, wherein the scaffold has a maximum expansion diameter of about 1 mm to about 5 mm.

15. The expandable tip assembly of claim 1, wherein the scaffold has a length of about from about 5 mm to about 50 mm.

16. 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;

a length configured to at least partially span the thrombus;

sufficient radial force to provide continuous radial expansion as the thrombus is lysed;

does not comprise a backbone; and

is not a rolled mesh scaffold that is configured to overlap on itself.

17. 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.

18. The expandable tip assembly of claim 1, wherein the scaffold comprises an open distal end without a distal embolic protection member or device.

19. The expandable tip assembly of claim 1, wherein a proximal end of the scaffold is tapered to facilitate re-sheathing of the scaffold.

20. The expandable tip assembly of claim 1, wherein the scaffold comprises a laser-cut tube.