Distal Embolic Protection Devices With A Variable Thickness Microguidewire And Methods For Their Use

• US 20090082800A1
• Filed: 09/21/2007
• Published: 03/26/2009
• Est. Priority Date: 09/21/2007
• Status: Active Grant

• Current Assignee: Insera Therapeutics, Inc.
• Original Assignee: Insera Therapeutics LLC
• Inventors: JANARDHAN, Vikram
• Granted Patent: US 9,034,007 B2
• Time in Patent Office: Days
• US Class Current: 606/200
• CPC Class Codes: A61F 2/011 Instruments for their placement or removal
• CPC Class Codes: A61F 2/013 Distal protection devices, i.e. devices placed distally in combination with another endovascular procedure, e.g. angioplasty or stenting
• 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 2230/008 paraboloidal
• CPC Class Codes: A61M 25/09 Guide wires

Abstract

A distal embolic protection device for dedicated use in cerebral arterial blood vessels is described. The distal embolic protection device comprises a variable-thickness micro-guidewire and a collapsible filtering device mounted on the microguidewire over two mobile attachment points so that in its collapsed configuration, the thickness of the microguidewire and the filtering device at this region is less than or equal to 0.017 inch (0.432 mm) in thickness to be able to pass through existing conventional microcatheters. The mobile attachment points allow for rotatory and longitudinal mobility of the microguidewire while the filtering device is stable thereby decreasing the risk of trauma to the fragile cerebral arterial blood vessels. Preferably, the filtering device comprises an expansion assembly, e.g., a plurality of struts attached to a filter membrane that are in a folded position which self expand to the desired dimensions within the cerebral blood vessels. Also described are methods of using the distal embolic protection devices of this invention.

Claims

1. A distal embolic protection device for filtering thrombo-embolic material, debris or clots released during percutaneous neurovascular interventional procedures specifically performed in cerebral arterial blood vessels, not inherently attached to a balloon or a stent, and comprising

a. a variable thickness microguidewire comprising a thinner segment bordered by thicker segments, and

b. a filtering device movable between an expanded configuration and a collapsed configuration, for deploying beyond an area of blockage or clot in a cerebral arterial blood vessel;

the filtering device comprising an expansion assembly, a filter membrane, and a mobile attachment point,

wherein the filtering device is rotatably mounted on the variable thickness microguidewire via the mobile attachment point, such that the filtering device may be rotationally and longitudinally displaced relative to and independently of the microguidewire, and wherein the thickness of the distal embolic protection device in the collapsed configuration measures no more than about 0.017 inch (0.432 mm).

2. The distal embolic protection device of claim 1, wherein:

a. the expansion assembly comprises a plurality of struts, or a single ring, or both a plurality of struts and a single ring, wherein said struts or ring or both comprise a biocompatible material, said biocompatible material being platinum, stainless steel, or nickel-titanium, and

b. the filtering device is no more than about 0.017 inch (0.432 mm) in thickness in the collapsed configuration, and in the expanded configuration the filtering device has diameter of from about 1.5 mm to 4.5 mm and

c. the filter membrane has a hemispherical, helical or conical shape.

3. The distal embolic protection device of claim 1, wherein:

a. the thinner segment of the microguidewire is no more than about 0.010 inch (0.254 mm) in thickness, and said filtering device is rotatably mounted on the thinner segment, such that in the collapsed configuration, the overall thickness of the said distal embolic protection device is less than or equal to 0.017 inch (0.432 mm).

b. the thicker segments of the microguidewire are no more than about 0.014 inch (0.356 mm) in thickness, and the microguidewire has a length ranging from about 190 cm to about 300 cm.

4. The distal embolic protection device of claim 1, wherein:

a. the thinner segment of the microguidewire where the filtering device is mounted comprise predominantly a core microguidewire that is made up of a metal or alloy, said metal being stainless steel and said alloy being nickel-titanium.

b. the thicker segment of the microguidewire comprise a core microguidewire that may be coated or covered by another layer of a coil or a flexible hypotube or a combination of both that is made up of a radio-opaque material or metal or alloy, said radio-opaque material or metal being platinum and said alloy being nickel-titanium.

5. The distal embolic protection device of claim 1, wherein:

a. the microguidewire comprises a proximal and a distal stop where the thinner segment of the microguidewire meets a thicker segment of the microguidewire, wherein the thickness of the stops is about 0.014 inch to about 0.017 inch (0.356 mm to about 0.432 mm) and

b. the filtering device comprises a distal mobile attachment point, and a proximal mobile attachment point, wherein the mobile attachment points are rotatably attached to the thinner segment of the microguidewire between the proximal and distal stops, such that there is rotatory as well as longitudinal mobility of the microguidewire through, and independently of, the filtering device between the proximal and distal stops.

6. The distal embolic protection device of claim 1, further comprising cylindrical coils attached to the distal and proximal mobile attachment points and attached to the proximal and distal stops, wherein the overall thickness of the cylindrical coils is less than or equal to 0.017 inch (0.432 mm), and the cylindrical coils comprising a radio-opaque material.

7. The distal embolic protection device of claim 6, wherein the radio-opaque material is tantalum, platinum, tungsten or gold.

8. The distal embolic protection device of claim 1, wherein:

the mobile attachment points are short and do not cover the entire length of the thinner segment of the microguidewire

9. The distal embolic protection device of claim 1, wherein:

the filter membrane comprises a biopolymer having pores large enough to allow blood cells to pass through the filter but small enough to capture debris and clots that are released during percutaneous neurovascular interventional procedures in the cerebral arterial blood vessels.

10. The distal embolic protection device of claim 9, wherein the pore openings are about 50-150 microns in diameter.

11. The distal embolic protection device of claim 1, wherein:

the distal portion of the filtering device is covered by the filter membrane, and wherein the filter membrane comprises;

a. a biomedical polymer;

b. a biomedical polymer selected from the group consisting of polyurethane, polyethylene, polyester, polypropylene, poly tetra fluoro-ethylene, polyamides, polycarbonate and polyethylene-terepthalate, or

c. a membrane comprising a biomedical polymer and radio-opaque particles or agents wherein the radio-opaque biomedical polymer is visible during fluoroscopic neurovascular interventional procedures.

12. The distal embolic protection device of claim 11, wherein the radio-opaque particles are tantalum or gold and the radio-opaque agents are barium sulfate, tungsten powder, bismuth subcarbonate, bismuth oxychloride, or iodine containing compounds.

13. The distal embolic protection device of claim 1, wherein:

the expansion assembly comprises a plurality of struts, or a single ring, or a plurality of struts and a single ring

14. The distal embolic protection device of claim 13, wherein the plurality of struts and ring comprise a biocompatible metal or alloy or a radio-opaque material.

15. The distal embolic protection device of claim 14, wherein the biocompatible metal or alloy is stainless steel, platinum or nickel-titanium and the radio-opaque material is tantalum, platinum, tungsten or gold.

16. The distal embolic protection device of claim 1, wherein the microguidewire comprises a shapeable tip, and wherein the distal segment of the microguidewire that corresponds to the distal 30 cm or less, the shapeable tip of the microguidewire, the proximal and distal mobile attachments points, and the proximal and distal stops, are covered by a radio-opaque material, metal or alloy.

17. The distal embolic protection device of claim 16, wherein the metal or alloy is stainless steel or nickel-titanium, and the radio-opaque material is tantalum, platinum, tungsten or gold.

18. A method for collecting thrombo-embolic material, debris or clots released during percutaneous neurovascular interventional procedures specifically performed in the cerebral arterial blood vessels, comprising inserting the distal embolic protection device of claim 1 into a cerebral arterial blood vessel having an area of stenosis or a clot, deploying the filtering device distal to the area of blockage or clot and allowing the filtering device to expand to fill the diameter of the cerebral arterial blood vessel.

19. The method of claim 18, comprising advancing a standard microcatheter over a standard microwire across the area of stenosis or clot, positioning the microcatheter distal to the stenosis or clot, withdrawing the microwire, and advancing the distal embolic protection device through the standard microcatheter.

20. The method of claim 18, comprising advancing the distal embolic protection device through a standard microcatheter wherein the thickness of the variable thickness microguidewire, except for the thinner section, is about 0.014 inch (0.356 mm).

21. A method of claim 18, comprising advancing the distal embolic protection device through a standard microcatheter having an inner lumen diameter of about 0.017 inch (0.432 mm), wherein said distal embolic protection device has a thickness of no more than about 0.017 inch (0.432 mm).

22. The method of claim 19, further comprising withdrawing the microcatheter while keeping the microguidewire in position distal to the stenosis or clot, unsheathing the distal embolic protection device and expanding the filtering device to the pre-defined size inside the cerebral arterial blood vessel ranging from 1.5 mm to 4.5 mm and wherein the expanded shape of the filter membrane is a hemispherical, helical or conical shape.

23. The method of claim 22, further comprising maintaining the microguidewire in position, exchanging the standard microcatheter for (1) a balloon catheter to perform balloon angioplasty of the cerebral arterial blood vessels, or (2) a stent catheter to perform stenting of the cerebral arterial blood vessels, and collecting any debris or clots that are dislodged during the balloon angioplasty and or stenting in the cerebral arterial blood vessels in the filter membrane of the distal embolic protection device.

24. A method of claim 23, comprising maintaining the microguidewire in position, administering a clot dissolving drug or a thrombolytic- to a stroke patient or a patient in need thereof through a standard microcatheter, such that any debris or clots that are dislodged during the clot dissolving drug or thrombolytic infusion in the cerebral arterial blood vessels will be collected by the distal embolic protection device.

25. A method of claim 18, further comprising recovering the distal embolic protection device by advancing a standard microcatheter, balloon catheter, or stent catheter over the variable thickness microguidewire, and withdrawing the distal embolic protection device and the standard microcatheter, balloon catheter or stent catheter.