Vascular filter with improved strength and flexibility

• US 20030153943A1
• Filed: 11/26/2002
• Published: 08/14/2003
• Est. Priority Date: 03/12/2001
• Status: Active Grant

• Current Assignee: Don Michael International, LLC, Memory Metal Holland BV.
• Original Assignee: Peter Besselink, T. Anthony Don Michael
• Inventors: Michael, T. Anthony Don, Besselink, Peter
• Granted Patent: US 7,214,237 B2
• Time in Patent Office: Days
• US Class Current: 606/200
• CPC Class Codes: A61F 2/012 Multiple filtering units
• 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 2230/005 Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2230/008 paraboloidal
• CPC Class Codes: A61F 2230/0093 Umbrella-shaped, e.g. mushroom-shaped

Abstract

A medical device, such as a vascular filter, composed of: a reinforced membrane unit composed of: a thin filter membrane; and fibers of reinforcement material embedded in the membrane to strengthen the filter and securely attach the fibers to the membrane.

A method of fabricating the filter by the steps of: providing a mold that can be melted, dissolved, or deformed without damaging membrane material; covering the mold with an intermediate material that is easily separated from the membrane material; covering the intermediate material with the membrane material; placing the fibers in contact with the membrane material that covers the intermediate material; covering the fibers with additional membrane material to form the membrane with embedded fibers; removing the mold by melting, dissolving, or deforming the mold; and removing the intermediate material from the membrane.

Claims

1. A medical device comprising:

a reinforced membrane unit composed of;

a thin filter membrane; and

fibers of reinforcement material embedded in said membrane to strengthen said filter and securely attach said fibers to said membrane.

2. The device of claim 1, further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape.

3. The device of claim 2, wherein said frame is constructed to collapse and expand said membrane unit.

4. The device of claim 3, constituting a filter and said membrane contains a pattern of holes to allow passage of a body fluid, while preventing passage of particles above a certain critical size.

5. The device of claim 4 constituting a blood filter, wherein said holes allow passage of normal blood flow while preventing passage of emboli above the certain critical size.

6. The device of claim 1, wherein said fibers of reinforcement material have a tensile stress and modulus of elasticity greater than the material of said membrane.

7. The device of claim 1, wherein said fibers of reinforcement material are composed of fibers of different types, including fibers for shape control combined with fibers with high tensile strength.

8. The device of claim 1, wherein said fibers of reinforcement material are monofilament or multi-filament fibers.

9. The device of claim 1, wherein said fibers of reinforcement material are coated with a polymer to enhance adhesion to said membrane.

10. The device of claim 9, wherein said fibers of reinforcement material are glued to said membrane with a solvent for the material of said membrane.

11. The device of claim 1, wherein said membrane is made of a polymer, an organic tissue, or a tissue of human or animal origin.

12. The device of claim 1, wherein said membrane is constituted by a mesh.

13. The device of claim 1, wherein the reinforcement material is selected from:

carbon;

glass;

metals;

metal alloys;

polymers; and

combinations thereof.

14. The device of claim 1, further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape, and wherein said fibers of reinforcement material are attached to or in said membrane and to said frame by one of:

dipping;

spraying welding;

glueing;

stitching;

pressing;

application of heat, application of light; and

tying.

15. The device of claim 1, further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape, and wherein said fibers are an integral part of said frame.

16. The device of claim 1, further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape, and wherein said fibers are attached to said frame by connections that form hinges to increase the flexibility of said device.

17. The device of claim 1, further comprising:

a frame attached to said membrane unit to hold said membrane unit in a desired shape, said frame having a proximal end remote from said membrane unit;

a guide wire; and

additional fibers connecting said proximal end of said frame to said guide wire for enabling said device to be retracted into a removal sheath by a pulling force on said guide wire in order to retrieve said device from a body passage.

18. The device of claim 1, further comprising:

a frame attached to said membrane unit to hold said membrane unit in a desired shape, said frame having a proximal end remote from said membrane unit and a distal end facing said membrane unit; and

a guide wire; and

wherein said fibers of reinforcement material are connected between said distal end of said frame and said guide wire for enabling said device to be extracted from a delivery sheath by pushing on said guide wire to impose a pulling force on said membrane unit in order to introduce said device into a body passage.

19. The device of claim 1, further comprising:

a frame attached to said membrane unit to hold said membrane unit in a desired shape;

slide rings connected to opposing ends of said device; and

a guide wire, and wherein said guide wire has a large diameter section for applying displacement forces to said slide rings.

20. The device of claim 19, wherein frame has a proximal end and a distal end, and said fibers have a first end directly attached to one of said slide rings and a second end attached to said distal end of said frame.

21. The device of claim 20, further comprising and additional fibers connecting said proximal end of said frame to said guide wire for enabling said device to be retracted into a removal sheath by a pulling force on said guide wire in order to retrieve said device from a body passage.

22. The device of claim 1, further comprising:

a frame attached to said membrane unit to hold said membrane unit in a desired shape, said frame having a proximal section that is tapered to facilitate retraction of said frame into a sheath.

23. The device of claim 1, wherein said fibers are coated with or embedded in a biocompatible material that prevents the adherence of emboli or platelets, or releases active drugs to a patient'"'"'s body.

24. The device of claim 1 in combination with a guide wire provided with a pressure sensing tip for continuous monitoring of blood pressure.

25. The device of claim 1 in combination with a guide wire that has a longitudinal axis, said device further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape, said frame being expandable, and said frame being constructed to allow said guide wire to move freely within said frame, in axial, radial and tangential directions when said frame is expanded, and to rotate around the longitudinal axis, without influencing the position and shape of said device.

26. The device of claim 1, forming one filter of a double filter system.

27. The device of claim 1, further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape, wherein said frame has a proximal side that faces away from said membrane unit provided with elongated struts to facilitate displacement of said device.

28. The device of claim 27, wherein said fibers are connected to said struts by means of attachment holes in the struts or by gluing or welding.

29. The device of claim 27, wherein said struts are configured for anchoring said filter in a body passage.

30. The device of claim 1 in combination with a hollow tube, said device further comprising a frame attached to said membrane unit to hold said membrane unit in a desired shape, wherein said filter is expandable into an open condition for obturating a body passage and said device is deformable to allow said tube to be advanced into a region enclosed by said membrane unit when said device is in said open condition.

31. The device of claim 30 wherein said tube can be advanced into the region enclosed by said membrane unit for performing at least one of:

suction;

flushing;

inspection;

measuring;

breaking up of clots; and

introduction of a retrieval device to remove particles from within said device.

32. The device of claim 31 wherein said hollow tube is dimensioned to serve as a removal sheath for said device.

33. The device of claim 1, constituting a filter, wherein said filter is expandable into an open condition, and said membrane unit has a closed end and an open end and is composed of a main portion that tapers from said open end an has a minimum diameter at a location remote from said open end to, and a reservoir portion that extends from said closed end toward said main portion, said reservoir portion having a maximum diameter that is greater than the minimum diameter of said main portion, and said reservoir portion constitutes a debris storage space that enhances maintenance of the blood flow through said filter when said filter is in the open condition in a blood vessel.

35. The device of claim 1, wherein said fibers include reinforcing fibers that allow said device to expand until a predetermined expanded size limit is reached.

36. The device of claim 35, wherein said reinforcing fibers are oriented in such a way as to give said membrane a shape that depends of the pressure difference over the membrane, within predetermined limits.

37. A method of fabricating the device of claim 1, comprising:

providing a mold that can be removed without damaging membrane material;

covering the mold with an intermediate material that is easily separated from the membrane material;

covering the intermediate material with the membrane material;

placing the fibers in contact with the membrane material that covers the intermediate material;

covering the fibers with additional membrane material to form the membrane with embedded fibers;

removing the mold; and

removing the intermediate material from the membrane.

38. The method of claim 37 wherein said step of removing the mold is carried out be melting, dissolving, or deforming the mold.

39. The method of claim 38, wherein the mold is made of a material that dissolves in a liquid.

40. The method of claim 38, wherein the mold is made of a sheath filled with fine solid grains and then vacuum sealed.

41. The method of claim 38, wherein the mold is an expandable or inflatable structure.

42. The method of claim 38, further comprising coating the membrane unit with an additional material having a property not possessed by the materials of the membrane unit.

34. The device of claim 34, wherein the diameter of said filter varies between the closed end and the open end to optimise blood flow and debris storage capacity.

43. A method for preventing embolism and microembolism in a blood flow circuit incident to performance of a treatment at a location in a blood vessel, said method comprising:

introducing a first filter element into the blood vessel downstream of the location so that the first filter element obturates the blood vessel;

performing the treatment;

introducing a second filter element into the blood vessel upstream of the location so that the second filter element obturates the blood vessel; and

after the step of performing a treatment, bringing the first and second filter elements close to one another, radially collapsing the first and second filter elements and withdrawing the first and second filter elements from the blood vessel,

wherein said treatment is one of;

disintegrating an obstruction in the blood vessel with laser radiation;

disintegrating an obstruction in the blood vessel with ultrasound energy;

disintegrating an obstruction in the blood vessel by mechanical cutting;

angioplasty; and

stenting.

44. A system for preventing embolism and microembolism in a vascular system, said system comprising:

a guiding catheter having an outer surface;

a blocking balloon carried by said guiding catheter on said outer surface

an elongated support element arranged to extend through, and beyond, said guiding catheter;

a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition;

a second filter element surrounding said support element and radially expandable from a closed condition to an open condition; and

means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions,

wherein each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood.

45. A system for preventing embolism and microembolism in a vascular system, said system comprising:

an elongated support element;

a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition;

a second filter element surrounding said support element and radially expandable from a closed condition to an open condition; and

means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, wherein

each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood; and

at least one of said filter elements comprises;

an armature constituted by a mesh or screen made of a resiliently deformable material; and

a, sheet of polymer filter material secured to said armature and providing said filter surface.

46. A system for preventing embolism and microembolism in a vascular system, said system comprising:

an elongated support element;

a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition;

a second filter element surrounding said support element and radially expandable from a closed condition to an open condition; and

means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, wherein;

each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood; and

one of said filter elements comprises;

an armature made of a resiliently deformable material and having an open end;

a sheet of polymer filter material secured to said armature and providing said filter surface;

a flexible additional filter sheet secured to the open end of said armature; and

a wire attached to said flexible additional filter sheet and extending to a point outside of the vascular system, said wire being movable at the point outside of the vascular system to alter the shape of said flexible additional filter sheet.

47. A method for performing angioplasty comprising:

aligning a first balloon with an obstruction in a blood vessel, the first balloon being radially outwardly expandable;

interposing a second balloon between the first balloon and the obstruction, the second balloon being annular so as to enclose a space, and being radially outwardly expandable;

expanding the first balloon to support the second balloon;

expanding the second balloon to dilate the obstruction;

blocking blood flow in the vessel at a location downstream of the obstruction;

deflating and withdrawing the first balloon;

performing a procedure on the blood vessel between the location where the blood vessel is blocked and the second balloon by introducing a treatment device or substance through the space enclosed by the second balloon.

48. The method of claim 47, further comprising, before said step of performing a procedure, deflating the second balloon, withdrawing the second balloon to a point upstream of the obstruction, and reinflating the second balloon.