MAGNETICALLY RETRIEVABLE VENA CAVA FILTER AND RETRIEVAL DEVICE THEREFOR

• US 20120130418A1
• Filed: 10/05/2011
• Published: 05/24/2012
• Est. Priority Date: 11/18/2010
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Jenson, Mark L., Hastings, Roger
• Granted Patent: US 8,657,848 B2
• Time in Patent Office: Days
• US Class Current: 606/200
• CPC Class Codes: A61F 2/0103 With centering means
• CPC Class Codes: A61F 2/0105 Open ended, i.e. legs gathered only at one side
• CPC Class Codes: A61F 2002/016 made from wire-like elements
• CPC Class Codes: A61F 2210/009 magnetic
• CPC Class Codes: A61F 2230/005 Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0067 conical

Abstract

The disclosure pertains to magnetically retrievable vena cava filters having a low torque associated therewith when subjected to a strong external magnetic field and retrieval devices therefor. The vena cava filter may include a magnetically permeable sphere or a spherical dipole magnet located within the spherical cavity of the apical hub wherein the spherical dipole magnet is free to rotate about any of three mutually orthogonal axes. The retrieval device is capable of substantially containing the vena cava filter in a collapsed state and includes a magnetically active member capable of interacting with the vena cava filter. The retrieval device may optionally include a supplemental mechanical latch.

Claims

1. A magnetically retrievable vena cava filter having a low torque associated therewith when subjected to a strong magnetic field and a retrieval system therefor, said filter comprising:

an apical hub;

a plurality of legs each having a first end fixedly attached to the apical hub and a second free end, said plurality of legs defining a generally conical filter basket in a deployed configuration;

a magnetically permeable sphere fixedly attached to the apical hub.

2. The magnetically retrievable vena cava filter of claim 1, wherein the magnetization of the magnetically permeable sphere tracks the magnetic field direction of an applied strong magnetic field.

3. The magnetically retrievable vena cava filter of claim 1, wherein each of the plurality of legs has associated with its free end a tissue anchor.

4. The magnetically retrievable vena cava filter of claim 1, wherein the magnetically permeable sphere comprises mu metal,

5. The magnetically retrievable vena cava filter of claim 1, wherein the magnetically permeable sphere comprises one or more of soft iron, nickel-iron alloys, nickel-iron-molybdenum, iron-silicon-aluminum alloys, iron-boron-silicon alloys, or low-hystresis loss ferrites.

8. The magnetically retrievable vena cava filter of claim 1, wherein the spherical dipole magnet comprises neodymium-iron-boron.

9. The magnetically retrievable vena cava filter of claim 1, wherein the spherical dipole magnet comprises samarium-cobalt.

6. A magnetically retrievable vena cava filter having a low torque associated therewith when subjected to a strong magnetic field, said filter comprising:

an apical hub defining therein a generally spherical cavity;

a plurality of legs each having a first end fixedly attached to the apical hub and a second free end, said plurality of legs defining a generally conical filter basket in a deployed configuration; and

a spherical dipole magnet located within the spherical cavity of the apical hub wherein the spherical dipole magnet is free to rotate about any axis passing through the center of the sphere.

7. The magnetically retrievable vena cava filter of claim 6, wherein each of the plurality of legs has associated with its free end a tissue anchor.

10. A retrieval device for a magnetically retrievable vena cava filter having a low torque associated therewith when subjected to a strong magnetic field, said retrieval device comprising:

an elongated shaft having a proximal end and a distal end;

a housing having a proximal end, a distal end, and a lumen therebetween wherein the proximal end of the housing is fixedly attached to the distal end of the elongated shaft, said housing being sized and adapted to receive substantially an entire magnetically retrievable vena cava filter in a collapsed configuration; and

a magnetically active member actuatable within the housing from a first position in which at least a portion of the magnetically active member extends distally beyond the housing to a second position in which the magnetically active member is located near the proximal end of the housing.

11. The retrieval device of claim 10, further comprising a filter engaging member.

12. The retrieval device of claim 11, wherein the filter engaging member is configured to mechanically latch to at least one of the apical hub of the filter, a magnetically permeable sphere, or at least one leg of the magnetically retrievable vena cava filter.

13. The retrieval device of claim 12, wherein the filter engaging member is configured to move distally past at least one of the apical hub of the filter or a magnetically permeable sphere and not to move proximally past said apical hub of the filter or a magnetically permeable sphere.

14. The retrieval device of claim 13, wherein the filter engaging member comprises one or more wires biased toward the longitudinal axis of the magnetically retrievable vena cava filter.

15. The retrieval device of claim 13, wherein the filter engaging member comprises a shape memory material having a first disengaged configuration which lies substantially along the wall of the housing and a second engaged configuration which lies closer to the longitudinal axis of the magnetically retrievable vena cava filter.

16. The retrieval device of claim 10, wherein the magnetically active member is adapted to magnetically attract at least one of a magnetically permeable sphere fixedly attached to the apical hub of the vena cava filter or spherical dipole magnet is free to rotate about any axis passing through the center of the sphere.

17. The retrieval device of claim 16, wherein the magnetically active member is a permanent magnet.

18. The retrieval device of claim 16, wherein the magnetically active member is an electromagnet.

19. The retrieval device of claim 16, wherein the magnetically active member is magnetically permeable.

20. The retrieval device of claim 11, wherein the filter engaging member is operably connected to an actuator located proximate the proximal end of the elongate shaft.