METHODS AND APPARATUS FOR FLOW RESTORATION

• US 20110060212A1
• Filed: 02/20/2009
• Published: 03/10/2011
• Est. Priority Date: 02/22/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Micro Therapeutics, Inc. (Medtronic Plc)
• Inventors: Wilder, Thomas III, Slee, Earl Howard, Ashby, Mark Philip, Franco, David, McCarthy, Thomas, Shrivastava, Sanjay
• Granted Patent: US 8,940,003 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 17/22 Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for dilators A61M29/00
• 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 2017/22034 for gripping the obstruction or the tissue part from inside
• CPC Class Codes: A61B 2017/22094 for crossing total occlusions, i.e. piercing
• CPC Class Codes: A61B 2017/2215 having an open distal end
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• 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 2/92 Stents in the form of a rolled-up sheet expanding after insertion into the vessel , e.g. with a spiral shape in cross-section

Abstract

Methods for restoring blood flow in occluded blood vessels using an apparatus having a self expandable distal segment that is pre-formed to assume a superimposed structure in an unconstrained condition but can be made to take on a volume-reduced form making it possible to introduce it with a microcatheter and a push wire arranged at the proximal end, with the distal segment in its superimposed structure assuming the form of a longitudinally open tube and having a mesh structure of interconnected strings or filaments or struts. In a preferred embodiment, the distal segment has a tapering structure at its proximal end where the strings or filaments or struts converge at a connection point.

Claims

1. A method for restoring localized blood flow in a blood vessel occluded with a thrombus comprising:

delivering a self-expandable apparatus to a site radially adjacent to the thrombus, the apparatus comprising a structure having a proximal end and a distal end, the structure having a distal portion comprising a first plurality of cells and a tapering portion comprising a second plurality of cells, the tapering portion being disposed toward the proximal end of the structure, the apparatus further comprising a connection point located at a proximal end of the tapering portion wherein the tapering portion converges at the connection point, the connection point attached to a guidewire located proximally of the apparatus, the apparatus further comprising a seam along a longitudinal axis of the structure, the seam forming two edges extending longitudinally along the structure, wherein the structure is preformed to assume a superimposed structure at the place of implantation, the superimposed structure being tubular and extending along a longitudinal direction, and wherein the structure is configured to be modified into a volume reduced form having a coiled configuration for insertion within a microcatheter, the two edges being overlapped in the coiled configuration such that in the coiled configuration the structure has multiple layers in at least one radial direction;

and

expanding the apparatus against the thrombus, causing an outward radial force on the thrombus, thereby restoring blood flow; and

retrieving the apparatus, and at least a portion of the thrombus, by pulling proximally on the guidewire.

5. The method of claim 1, wherein the apparatus is delivered through a microcatheter.

7. The method of claim 5, wherein the apparatus is expanded by moving the microcatheter proximally and/or by moving the apparatus distally, thereby exposing the apparatus from a distal end of the microcatheter.

10. The method of claim 5, wherein the microcatheter is positioned to be radially adjacent to the thrombus prior to expanding the apparatus against the thrombus.

11. The method of claim 10, wherein the distal end of the microcatheter is positioned distal to the thrombus.

12. The method of claim 1, wherein between about 10% and 60% of the thrombus circumference is separated from the vessel wall after the apparatus is expanded within the vessel, and a cross-sectional area of the thrombus is reduced due to the expansion of the apparatus, thereby lowering the force required to dislodge and mobilize the thrombus.

13. The method of claim 1, further comprising delivering to the thrombus an effective amount of a clot-busting drug.

16. The method of claim 1 wherein at least the distal portion of the apparatus is configured to engage at least a portion of the thrombus to form a removable, integrated apparatus-thrombus mass.

19. The method of claim 1, wherein the apparatus is expanded for a time sufficient to restore blood flow in the blood vessel, and wherein the apparatus, at least a portion of the thrombus, and the microcatheter are all retrieved proximally through the blood vessel after blood flow has been restored.

20. The method of claim 5, further comprising determining that full deployment and expansion of the apparatus has occurred by fluoroscopic visualization of a first radiopaque marker located on the proximal end of the apparatus being aligned with or located distal of a second radiopaque marker on a distal end of the microcatheter.

21. The method of claim 1, wherein the connection point comprises an electrolytic detachment mechanism for releasably detaching the apparatus, the apparatus being electrolytically detached after expanding against the thrombus.

22. The method of claim 1, further comprising using aspiration to aid in proximal retrieval of the thrombus.

2-4. -4. (canceled)

6. (canceled)

8-9. -9. (canceled)

14-15. -15. (canceled)

17-18. -18. (canceled)

23. A self-expandable apparatus for removal of a thrombus in a blood vessel, comprising:

a structure having a proximal end and a distal end, the structure having a distal portion comprising a first plurality of cells and a tapering portion comprising a second plurality of cells, the tapering portion being disposed toward the proximal end of the structure, the apparatus further comprising a connection point located at a proximal end of the tapering portion wherein the tapering portion converges at the connection point, the connection point attached to a guidewire located proximally of the apparatus, the apparatus further comprising a seam along a longitudinal axis of the structure, the seam forming two edges extending longitudinally along the structure, wherein the structure is preformed to assume a superimposed structure at the place of implantation, the superimposed structure being tubular and extending along a longitudinal direction, and wherein the structure is configured to be modified into a volume reduced form having a coiled configuration for insertion within a microcatheter, the two edges being overlapped in the coiled configuration such that in the coiled configuration the structure has multiple layers in at least one radial direction.

24. The apparatus of claim 23, wherein the distal end of the structure comprises radiopaque markers having a spiral or eyelet shape.

25. The apparatus of claim 23, wherein the distal end of the structure is bent and extends distally at an acute angle relative to the longitudinal axis of the structure.

26. The apparatus of claim 23, wherein the distal end of the structure comprises a third plurality of cells and wherein said third plurality of cells has a smaller cell size than the second plurality of cells.

27. The apparatus of claim 23, wherein the distal end of the structure comprises one or more pegs and/or hooks.

28. The apparatus of claim 23, wherein the distal end of the structure further comprises the addition of synthetic fibers wrapped or wound around at least a portion of the second plurality of cells.

29. The apparatus of claim 23, wherein the distal end of the structure has been heated for a sufficient time to provide increased radial strength.

30. The apparatus of claim 23, wherein the structure is coated with an anticoagulant or antiplatelet drug.

31. The apparatus of claim 30, wherein the structure is further coated with a biodegradable, biocompatible polymer to provide for sustained release of the anticoagulant or antiplatelet drug.

32. The apparatus of claim 23, wherein the structure comprises reservoirs to hold an anticoagulant or antiplatelet drug.

33. (canceled)