Collapsible blood filter with optimal braid geometry

• US 20020004667A1
• Filed: 12/12/2000
• Published: 01/10/2002
• Est. Priority Date: 05/24/2000
• Status: Active Grant

• Current Assignee: Medtronic Ave Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Ave Incorporated (Medtronic Plc)
• Inventors: Adams, Bruce, Brightbill, Jerry R., Brooks, Dennis L., Douk, Nareak, Rafiee, Nasser, Lashinski, Robert D., Brin, David S., Malek, Ahmed
• Granted Patent: US 6,602,271 B2
• Time in Patent Office: Days
• US Class Current: 606/200
• 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 2002/015 Stop means therefor
• 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 2230/008 paraboloidal

Abstract

The present invention is a collapsible blood filter for use during a vascular procedure, such as angioplasty or stent deployment. A filter made of braided filaments is located on the distal end of a delivery member, and the filter is deployed downstream of the vascular treatment site to capture emboli released during and immediately after the procedure. Optimal braid geometry of the filter ensures that captured emboli will be retained during collapse and removal of the filter following the procedure.

Claims

1. A collapsible blood filter for capturing emboli during an endovascular procedure at a treatment site, the filter comprising a tube formed by braided filaments that define pores, the filter having at least one inlet opening that is substantially larger than the pores, the filter having an axis and tapered ends, wherein relative movement of the ends along the axis accompanies transformation of the filter between a collapsed configuration and a deployed configuration, and wherein the pore-defining filaments of the braided tube form a maximum included angle of about 90 degrees, as measured across the axis when the filter is in the deployed configuration.

2. The blood filter of claim 1 wherein at least a portion of the filter between the ends is cylindrical in shape when the filter is in the deployed configuration.

3. The blood filter of claim 1 wherein the shape of the deployed configuration is ovoid.

4. The blood filter of claim 1 wherein the deployed configuration is sized to fill a selected cross-sectional area distal to the treatment site.

5. The blood filter of claim 1 wherein at least one of the braid filaments is a wire comprising radiopaque metal.

6. A distal protection device for capturing emboli during an endovascular procedure at a treatment site, the device comprising:

a delivery member having a proximal end and a distal end; and

a collapsible filter adjacent the distal end of the delivery member, the filter comprising a tube formed by braided filaments that define pores, the filter having at least one inlet opening that is substantially larger than the pores, the filter having an axis and tapered ends, wherein relative movement of the ends along the axis accompanies transformation of the filter between a collapsed configuration and a deployed configuration, and wherein the pore-defining filaments of the braided tube form a maximum included angle of about 90 degrees, as measured across the axis when the filter is in the deployed configuration.

7. The distal protection device of claim 6 further comprising:

a sheath being slidingly moveable over at least part of the filter for transforming the filter between the deployed configuration and the collapsed configuration.

8. The distal protection device of claim 6 wherein the deployed configuration is sized to fill a selected cross-sectional area distal to the treatment site.

9. The distal protection device of claim 6 wherein at least one of the braid filaments is a wire comprising radiopaque metal.

10. A system for treating a vascular stenosis, comprising:

an elongate delivery member having proximal and distal ends;

a collapsible filter mounted adjacent the distal end of the delivery member, the filter having a tube formed by braided filaments that define pores, the filter having at least one inlet opening that is substantially larger than the pores, the filter having an axis and tapered ends, wherein relative movement of the ends along the axis accompanies a transformation of the filter between a collapsed configuration and a deployed configuration, and wherein the pore-defining filaments of the braided tube form a maximum included angle of about 90 degrees, as measured across the axis when the filter is in the deployed configuration; and

a vascular treatment catheter capable of being slidably disposed about the delivery member.

11. A system according to claim 10 further comprising a sheath capable of being slidably disposed about the delivery member and extendable over at least a proximal portion of the filter when the filter is in the collapsed configuration.

12. A system according to claim 10, wherein the vascular treatment catheter is a balloon angioplasty catheter.

13. A system according to claim 10, wherein the vascular treatment catheter is a stent delivery catheter.

14. A method of making a collapsible blood filter, the method comprising:

braiding wire-like filaments to form a tubular filter having pores therein, the filter having an axis, a deployed diameter and two ends, the filaments intersecting at a maximum angle of about 90 degrees, as measured across the axis when the filter is at the deployed diameter;

forming tapered ends on the filter by drawing the ends to a second diameter that is significantly smaller than the deployed diameter; and

heat treating the filter to fix a selected shape thereof.

15. The method of making a blood filter according to claim 14, further comprising:

forming at least one inlet opening in a tapered end of the filter, the opening having a selected size and shape that is substantially larger than the pores by forcing a mandrel of the selected size and shape into a pore formed by the braided filaments.

16. The method of making a blood filter according to claim 14, wherein the braiding step further includes braiding a distal portion of the filter body more tightly than the remainder of the body.

17. The method of making a blood filter according to claim 14, wherein the wire-like filaments comprise shape-memory metal wires.

18. The method of making a blood filter according to claim 14, wherein at least one of the wire-like filaments is a wire comprising radiopaque metal.