Filamentary devices for the treatment of vascular defects
Devices and methods for treatment of a patient's vasculature are described. The device includes a self-expanding resilient permeable shell having a radially constrained state and an expanded state with a globular, axially shortened configuration. The permeable shell may be a single layer of braided elongate filaments having first and second ends that are secured at the proximal end of the permeable shell. The devices may also include permeable shells made of woven braided mesh having a variable mesh density, i.e., the average size of pores in one region are a different than the average size of pores in another region. Methods of using the device to treat a cerebral aneurysm are also described. Methods of forming a tubular braid are also described. Methods of forming a tubular braid with variable braid densities are described. Methods of forming a tubular braid using a castellated mandrel are also described.
1. A device for treatment of an aneurysm within a patient's vasculature, comprising:
a self-expanding resilient permeable shell having a proximal end, a distal end, and a longitudinal axis, the shell comprising a plurality of elongate resilient filaments having a braided structure, each of the plurality of elongate filaments having a first end, a central section, and a second end, wherein the first and second ends of the plurality of filaments are secured at the proximal end of the permeable shell, wherein the permeable shell is a single layer of braided elongate resilient filaments;
wherein the permeable shell has a radially constrained elongated state configured for delivery within a microcatheter,
wherein the permeable shell has an expanded state having a length and a globular, axially shortened configuration relative to the radially constrained state, wherein the central section of each of the plurality of elongate filaments passes through a distal region of the permeable shell,
wherein the permeable shell has a distal region having a plurality of pores having an average diameter, a proximal region having a plurality of pores having an average diameter, and a transition region that lies substantially perpendicular to the longitudinal axis of the permeable shell and extends between the distal and proximal regions and has a length, the permeable shell in its expanded state having a region of maximum diameter that extends from a proximal portion of the distal region through the transition region and to a distal portion of the proximal region, wherein the average diameter of the plurality of pores in the distal region is greater than the average diameter of the plurality of pores in the proximal region.
2. The device of claim 1 , wherein the filaments are not secured together at the distal end of the permeable shell.
3. The device of claim 1 , wherein the plurality of filaments comprises filaments of at least two different transverse dimensions.
4. The device of claim 1 , wherein at least some of the filaments comprise platinum.
5. The device of claim 1 , wherein at least some of the filaments are drawn filled tubes.
6. The device of claim 1 , wherein at least a portion of the permeable shell is coated with a growth factor.
7. The device of claim 1 , wherein at least some of the filaments comprise bioresorbable filaments.
8. The device of claim 1 , further comprising an opening at the proximal end.
9. The device of claim 8 , wherein the opening has a diameter of at least one millimeter.
10. The device of claim 8 , wherein at least a portion of the permeable shell is configured to contain an embolic material.
11. The device of claim 1 , wherein the length of the transition region is about 0.5% to about 20% of the length of the implant.
12. The device of claim 1 , wherein the average diameter of the plurality of pores in the distal region is greater than 250 μm.
13. The device of claim 1 , wherein the average diameter of the plurality of pores in the proximal region is 200 μm or less.
14. The device of claim 1 , wherein the length of the transition region is about 1% to about 15% of the length of the implant.
15. The device of claim 1 , wherein the distal end of the permeable shell comprises a plurality of loops formed from single filaments.
16. The device of claim 1 , wherein the proximal end of the permeable shell comprises a plurality of loops formed from single filaments.
17. A method for treating a cerebral aneurysm, comprising the steps of:
providing an implant having:
a self-expanding resilient permeable shell having a proximal end, a distal end, and a longitudinal axis, the shell comprising a plurality of elongate resilient filaments having a braided structure, each of the plurality of elongate filaments having a first end, a central section, and a second end, wherein the first and second ends of the plurality of filaments are secured at the proximal end of the permeable shell, wherein the permeable shell is a single layer of braided elongate resilient filaments;
wherein the permeable shell has a radially constrained elongated state configured for delivery within a microcatheter,
wherein the permeable shell has an expanded state with an axially shortened configuration relative to the radially constrained state, wherein the central section of each of the plurality of elongate filaments passes through a distal region of the permeable shell, and
wherein the permeable shell has a distal region having a plurality of pores having an average diameter, a proximal region having a plurality of pores having an average diameter, and a transition region that lies substantially perpendicular to the longitudinal axis of the permeable shell and extends between the distal and proximal regions and has a length, the permeable shell in its expanded state having a region of maximum diameter that extends from a proximal portion of the distal region through the transition region and to a distal portion of the proximal region, wherein the average diameter of the plurality of pores in the distal region is greater than the average diameter of the plurality of pores in the proximal region;
advancing the implant in the radially constrained state within a microcatheter to a region of interest within a cerebral artery; and
deploying the implant within the cerebral aneurysm.
18. The method of claim 17 , further comprising the step of:
delivering an embolic material through the microcatheter and into an interior of the permeable shell of the deployed implant.
19. The method of claim 17 , further comprising the step of:
withdrawing the microcatheter from the region of interest.
20. The method of claim 17 , wherein the filaments are not secured together at the distal end of the permeable shell.
21. The method of claim 17 , wherein the length of the transition region is about 0.5% to about 20% of the length of the implant.
22. The method of claim 17 , wherein the average diameter of the plurality of pores in the distal region is greater than 250 μm.
23. The method of claim 17 , wherein the average diameter of the plurality of pores in the proximal region is 200 μm or less.
24. The method of claim 17 , wherein the length of the transition region is about 1% to about 15% of the length of the implant.