Vascular stenting for aneurysms
Described herein are flexible implantable occluding devices that can, for example, navigate the tortuous vessels of the neurovasculature. The occluding devices can also conform to the shape of the tortuous vessels of the vasculature. In some embodiments, the occluding devices can direct blood flow within a vessel away from an aneurysm or limit blood flow to the aneurysm. Some embodiments describe methods and apparatus for adjusting, along a length of the device, the porosity of the occluding device. In some embodiments, the occluding devices allows adequate blood flow to be provided to adjacent structures such that those structures, whether they are branch vessels or oxygen-demanding tissues, are not deprived of the necessary blood flow.
1. A device for reducing blood flow within an aneurysm of a blood vessel, the device comprising:
a first occluding device comprising a first tubular lattice structure having a compressed configuration for delivery through a catheter to the aneurysm and an expanded configuration in which the first occluding device is configured to be positioned within the lumen of the blood vessel across the neck of the aneurysm; and
a second occluding device comprising a second tubular lattice structure having a compressed configuration for delivery through a catheter to the aneurysm and an expanded configuration in which the second occluding device is configured to be positioned at least partially within the first occluding device such that the second lattice structure contacts an inner wall of the first lattice structure and/or the blood vessel wall,
wherein at least one of the first lattice structure and the second lattice structure is formed of a plurality of helically-wound strands of material, and wherein at least some of the strands are a shape memory material,
wherein, when positioned across the neck of the aneurysm, the device for reducing blood flow substantially blocks blood flow into the aneurysm,
wherein the second occluding device overlaps only a portion of the first occluding device when the second occluding device is expanded within the first occluding device, and
wherein the first occluding device has a proximal portion and a distal portion, and when the first occluding device is positioned in the blood vessel lumen, the proximal portion of the first occluding device is proximal to the aneurysm while the distal portion of the first occluding device is distal to the aneurysm.
2. The device of claim 1 , wherein the first occluding device has a first porosity when unrestrained and the second occluding device has a second porosity when unrestrained different than the first porosity.
3. The device of claim 1 , wherein the second occluding device has a proximal portion and a distal portion, and wherein, when the second occluding device is positioned at least partially within the first occluding device, the proximal portion of the second occluding device is positioned distal to the proximal portion of the first occluding device and the distal portion of the second occluding device is positioned proximal to the distal portion of the first occluding device.
4. The device of claim 1 , wherein at least one of the first lattice structure and the second lattice structure is formed of 16 helically-wound strands of material.
5. The device of claim 1 , wherein at least one of the first lattice structure and the second lattice structure is formed of 48 helically-wound strands of material.
6. The device of claim 1 , wherein at least one of the first lattice structure and the second lattice structure is a braid.
7. The device of claim 1 , wherein at least one of the first lattice structure and the second lattice structure is a stent.
8. The device of claim 1 , wherein the density of at least one of the first lattice structure and the second lattice structure is about 20% to about 80% of the surface area of the respective first or second occluding device.
9. The device of claim 1 , wherein the density of at least one of the first lattice structure and the second lattice structure is about 20% to about 50% of the surface area of the respective first or second occluding device.
10. The device of claim 1 , wherein the density of at least one of the first lattice structure and the second lattice structure is about 20% to about 30% of the surface area of the respective first or second occluding device.
11. A method for reducing blood flow within an aneurysm of a blood vessel, the method comprising:
expanding a first occluding device within the blood vessel lumen across the neck of the aneurysm such that the first occluding device expands into contact with a wall of the blood vessel, wherein the first occluding device comprises a first tubular lattice structure formed of first helically-wound strands of material, and wherein at least some of the first strands are a shape memory material;
expanding a second occluding device into contact with an inner wall of the first occluding device and/or the vessel wall, wherein the second occluding device comprises a second tubular lattice structure formed of second helically-wound strands of material, and wherein at least some of the second strands are a shape memory material, wherein (a) the second occluding device overlaps only a portion of the first occluding device when the second occluding device is expanded within the first occluding device, and (b) the first occluding device has a proximal portion and a distal portion and, when the first occluding device is positioned in the blood vessel lumen, the proximal portion of the first occluding device is proximal to the aneurysm while the distal portion of the first occluding device is distal to the aneurysm; and
substantially blocking blood flow into the aneurysm via the first and second occluding devices.
12. The method of claim 11 wherein the first occluding device has a first porosity when unrestrained and the second occluding device has a second porosity different than the first porosity when unrestrained.
13. The method of claim 11 , wherein the second occluding device has a proximal portion and a distal portion, and wherein, when the second occluding device is positioned at least partially within the first occluding device, the proximal portion of the second occluding device is positioned distal to the proximal portion of the first occluding device and the distal portion of the second occluding device is positioned proximal to the distal portion of the first occluding device.
14. The method of claim 11 , wherein at least one of the first lattice structure and the second lattice structure is formed of 16 helically-wound strands of material.
15. The method of claim 11 , wherein at least one of the first lattice structure and the second lattice structure is formed of 48 helically-wound strands of material.
16. The method of claim 11 , wherein at least one of the first lattice structure and the second lattice structure is a braid.
17. The method of claim 11 , wherein at least one of the first lattice structure and the second lattice structure is a stent.
18. The method of claim 11 , wherein the density of at least one of the first lattice structure and the second lattice structure is about 20% to about 80% of the surface area of the respective first or second occluding device.
19. The method of claim 11 , wherein the density of at least one of the first lattice structure and the second lattice structure is about 20% to about 50% of the surface area of the respective first or second occluding device.
20. The method of claim 11 , wherein the density of at least one of the first lattice structure and the second lattice structure is about 20% to about 30% of the surface area of the respective first or second occluding device.
21. The method of claim 11 , wherein the aneurysm is a cerebral aneurysm.