U.S. patent application number 16/949568 was filed with the patent office on 2022-09-29 for devices, systems, and methods for treatment of intracranial aneurysms.
The applicant listed for this patent is Covidien LP. Invention is credited to Vincent Divino, Junwei Li, Ashok Nageswaran, Richard Rhee.
Application Number | 20220304696 16/949568 |
Document ID | / |
Family ID | 1000006588884 |
Filed Date | 2022-09-29 |
United States Patent
Application |
20220304696 |
Kind Code |
A2 |
Rhee; Richard ; et
al. |
September 29, 2022 |
DEVICES, SYSTEMS, AND METHODS FOR TREATMENT OF INTRACRANIAL
ANEURYSMS
Abstract
Systems and methods for treating an aneurysm in accordance with
embodiments of the present technology include intravascularly
delivering an occlusive member to an aneurysm cavity via an
elongated shaft and transforming a shape of the occlusive member
within the cavity. The method may include introduction of an
embolic element to a space between the occlusive member and an
inner surface of the aneurysm wall. In some embodiments, the
elongated shaft is detachably coupled to a distal portion of the
occlusive member.
Inventors: |
Rhee; Richard; (Anaheim,
CA) ; Divino; Vincent; (Mission Viejo, CA) ;
Nageswaran; Ashok; (Irvine, CA) ; Li; Junwei;
(Irvine, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Covidien LP |
Mansfield |
MA |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20210128162 A1 |
May 6, 2021 |
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|
Family ID: |
1000006588884 |
Appl. No.: |
16/949568 |
Filed: |
November 3, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62930421 |
Nov 4, 2019 |
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62930487 |
Nov 4, 2019 |
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62930303 |
Nov 4, 2019 |
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62930324 |
Nov 4, 2019 |
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62930333 |
Nov 4, 2019 |
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62930357 |
Nov 4, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/1214 20130101;
A61B 2017/12054 20130101; A61B 17/12113 20130101 |
International
Class: |
A61B 17/12 20060101
A61B017/12 |
Claims
1. A system comprising: an elongate shaft defining a lumen; an
elongate member slidably disposed within the lumen of the elongate
shaft, the elongate member having a proximal end region and a
distal end region, wherein the distal end region is configured to
be intravascularly position at or within an aneurysm cavity; an
occlusive member constrained within the lumen of the shaft, the
occlusive member including a proximal end portion having an opening
and a distal end portion detachably coupled to the distal end
region of the elongate member, wherein the elongate member extends
through the opening such that the wherein pushing the elongate
member from a distal opening in the elongate shaft pulls the
occlusive member distally through the distal opening to expel the
occlusive member from the shaft and allow the occlusive member to
expand to an expanded state.
2. The system of claim 1, further comprising an embolic element
configured to be delivered to the aneurysm cavity through the
elongate member while the elongate member is coupled to the distal
end portion of the occlusive member.
3. The system of claim 2, wherein the embolic element is a liquid
embolic, one or more embolic coils, or both.
4. The system of claim 1, wherein a portion of the occlusive member
surrounding the elongate member at the opening is configured to
slide relative to the elongate member as the occlusive member
self-expands.
5. The system of claim 1, wherein the occlusive member comprises
one or more preferential bending regions about all or a portion of
the circumference of the occlusive member.
6. The system of claim 5, wherein all or a portion of the one or
more preferential bending regions comprise a radiopaque
material.
7. The system of claim 1, wherein the expanded state is a first
expanded state and the occlusive member has a first shape in the
first expanded state, and wherein, when the occlusive member is in
the first expanded state in the aneurysm cavity and coupled to the
elongate member, proximal movement of the elongate member collapses
a distal wall of the occlusive member towards a proximal wall of
the occlusive member, thereby transforming the occlusive member
into a second expanded state in which the occlusive member has a
shape different than the first shape.
8. A method for treating an aneurysm, the method comprising:
positioning a distal end of an elongate shaft at or near an
aneurysm cavity, the distal end of the shaft containing an
occlusive member detachably coupled to an elongated member slidably
disposed within the elongated shaft, wherein a distal end of the
occlusive member is coupled to a distal end of the elongate member
and a proximal end of the occlusive member is slidable over the
elongate member; pushing the elongate member distally from a distal
opening in the elongate shaft to pull a distal end of the occlusive
member distally through the distal opening to expel the occlusive
member from the shaft and allow the occlusive member to self-expand
to a first expanded state; while the occlusive member is in the
first expanded state, pulling the elongate member proximally to
bring a distal wall of the occlusive member towards a proximal wall
of the occlusive member such that the occlusive member forms a
second expanded state in which at least a portion of the occlusive
member is inverted; and delivering an embolic element through the
elongate member to a position between the occlusive member and the
aneurysm wall.
9. The method of claim 8, wherein, as the occlusive member
self-expands, a proximal end of the occlusive member slides
distally along the elongate member.
10. The method of claim 8, wherein delivering the embolic element
occurs while the elongate member is pulled proximally.
11. The method of claim 8, further comprising inverting the
occlusive member at a pre-determined longitude defined by a bending
region along the occlusive member.
12. The method of claim 8, wherein the occlusive member has a
globular or generally spherical shape in the first expanded
state.
13. The method of claim 8, wherein the occlusive member is cup or
bowl-shaped in the second expanded state.
14. The method of claim 8, wherein the occlusive member forms a
multi-layer braid at the neck of the aneurysm in the second
expanded state, the multi-layer braid comprising a first layer
corresponding to the distal wall of the occlusive member and a
second layer corresponding to the proximal wall of the occlusive
member.
15. A method for treating an aneurysm, the method comprising:
positioning a distal end portion of an elongated shaft at or near
an aneurysm cavity, the distal end portion of the shaft containing
an occlusive member detachably coupled to an elongated member
slidably disposed within the elongated shaft, wherein a distal end
region of the occlusive member is coupled to a distal end of the
elongated member; expanding the occlusive member within the
aneurysm cavity; pulling the elongate member proximally, thereby
causing a first portion of the occlusive member to invert onto a
second portion of the occlusive member, wherein the first and
second portions meet at a circumferential fold; pushing the
elongate member distally, thereby causing the second portion to
move away from the first portion and at least partially reversing
the inversion of the occlusive member; and delivering an embolic
element through the elongate member to a space between a distal
wall of the occlusive member and a wall of the aneurysm.
16. The method of claim 15, further comprising delivering an
embolic element through the elongated member to a position between
the occlusive member and the aneurysm wall.
17. The method of claim 15, wherein pulling the elongate member
proximally occurs at a first time and the method further comprises
pulling the elongate member proximally at a second time after the
first time and after pushing the elongate member distally, wherein
pulling the elongate member proximally at the second time brings a
distal wall of the occlusive member towards a proximal wall of the
occlusive member such that the occlusive member forms a cup or bowl
shape.
18. The method of claim 17, wherein delivering the embolic element
occurs while the elongate member is being pulled proximally at the
second time.
19. The method of claim 15, wherein, as the occlusive member
expands, a proximal end region of the occlusive member slides
distally relative to the elongate member.
20. The method of claim 15, further comprising detaching the
elongate member from the distal end region of the occlusive member
and withdrawing the elongate member from the body.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application claims the benefit of priority of
U.S. Provisional Application No. 62/930,421, filed Nov. 4, 2019,
U.S. Provisional Application No. 62/930,487, filed Nov. 4, 2019,
U.S. Provisional Application No. 62/930,303, filed Nov. 4, 2019,
U.S. Provisional Application No. 62/930,324, filed Nov. 4, 2019,
U.S. Provisional Application No. 62/930,333, filed Nov. 4, 2019,
and U.S. Provisional Application No. 62/930,357, filed Nov. 4,
2019, each of which is incorporated by reference herein in its
entirety.
[0002] The following applications are also incorporated by
reference herein in their entireties: U.S. patent application Ser.
No. ______, filed concurrently herewith, and titled DEVICES,
SYSTEMS, AND METHODS FOR TREATMENT OF INTRACRANIAL ANEURYSMS
[Attorney Docket No. C00016119.US07]; U.S. patent application Ser.
No. ______, filed concurrently herewith, and titled SYSTEMS AND
METHODS FOR TREATING ANEURYSMS [Attorney Docket No.
C00016119.US09]; U.S. patent application Ser. No. ______, filed
concurrently herewith, and titled SYSTEMS AND METHODS FOR TREATING
ANEURYSMS [Attorney Docket No. C00016119.US10]; U.S. patent
application Ser. No. ______, filed concurrently herewith, and
titled ANEURYSM TREATMENT DEVICE [Attorney Docket No.
C00016119.US11]; U.S. patent application Ser. No. ______, filed
concurrently herewith, and titled ANEURYSM TREATMENT DEVICE
[Attorney Docket No. C00016119.US12]; U.S. patent application Ser.
No. ______, filed concurrently herewith, and titled DEVICES,
SYSTEMS, AND METHODS FOR TREATING ANEURYSMS [Attorney Docket No.
A0004461US01]; U.S. patent application Ser. No. ______, filed
concurrently herewith, and titled SYSTEMS AND METHODS FOR TREATING
ANEURYSMS [Attorney Docket No. A0004538US01]; U.S. patent
application Ser. No. ______, filed concurrently herewith, and
titled DEVICES, SYSTEMS, AND METHODS FOR TREATING ANEURYSMS
[Attorney Docket No. A0004556US01]; International application Ser.
No. ______, filed concurrently herewith, titled DEVICES, SYSTEMS,
AND METHODS FOR TREATMENT OF INTRACRANIAL ANEURYSMS [Attorney
Docket No. C00016119WO01]; International application Ser. No.
______, filed concurrently herewith, titled SYSTEMS AND METHODS FOR
TREATING ANEURYSMS [Attorney Docket No. C00016119WO02]; and
International application Ser. No. ______, filed concurrently
herewith, titled SYSTEMS AND METHODS FOR TREATING ANEURYSMS
[Attorney Docket No. C00016119WO03].
TECHNICAL FIELD
[0003] The present technology relates to systems, devices, and
methods for treating intracranial aneurysms.
BACKGROUND
[0004] An intracranial aneurysm is a portion of an intracranial
blood vessel that bulges outward from the blood vessel's main
channel. This condition often occurs at a portion of a blood vessel
that is abnormally weak because of a congenital anomaly, trauma,
high blood pressure, or for another reason. Once an intracranial
aneurysm forms, there is a significant risk that the aneurysm will
eventually rupture and cause a medical emergency with a high risk
of mortality due to hemorrhaging. When an unruptured intracranial
aneurysm is detected or when a patient survives an initial rupture
of an intracranial aneurysm, vascular surgery is often indicated.
One conventional type of vascular surgery for treating an
intracranial aneurysm includes using a microcatheter to dispose a
platinum coil within an interior volume of the aneurysm. Over time,
the presence of the coil should induce formation of a thrombus.
Ideally, the aneurysm's neck closes at the site of the thrombus and
is replaced with new endothelial tissue. Blood then bypasses the
aneurysm, thereby reducing the risk of aneurysm rupture (or
re-rupture) and associated hemorrhaging. Unfortunately, long-term
recanalization (i.e., restoration of blood flow to the interior
volume of the aneurysm) after this type of vascular surgery occurs
in a number of cases, especially for intracranial aneurysms with
relatively wide necks and/or relatively large interior volumes.
[0005] Another conventional type of vascular surgery for treating
an intracranial aneurysm includes deploying a flow diverter within
the associated intracranial blood vessel. The flow diverter is
often a mesh tube that causes blood to preferentially flow along a
main channel of the blood vessel while blood within the aneurysm
stagnates. The stagnant blood within the aneurysm should eventually
form a thrombus that leads to closure of the aneurysm's neck and to
growth of new endothelial tissue, as with the platinum coil
treatment. One significant drawback of flow diverters is that it
may take weeks or months to form aneurysmal thrombus and
significantly longer for the aneurysm neck to be covered with
endothelial cells for full effect. This delay may be unacceptable
when risk of aneurysm rupture (or re-rupture) is high. Moreover,
flow diverters typically require antiplatelet therapy to prevent a
thrombus from forming within the main channel of the blood vessel
at the site of the flow diverter. Antiplatelet therapy may be
contraindicated shortly after an initial aneurysm rupture has
occurred because risk of re-rupture at this time is high and
antiplatelet therapy tends to exacerbate intracranial hemorrhaging
if re-rupture occurs. For these and other reasons, there is a need
for innovation in the treatment of intracranial aneurysms. Given
the severity of this condition, innovation in this field has
immediate life-saving potential.
SUMMARY
[0006] The subject technology is illustrated, for example,
according to various aspects described below, including with
reference to FIGS. 1A-7J. Various examples of aspects of the
subject technology are described as numbered clauses (1, 2, 3,
etc.) for convenience. These are provided as examples and do not
limit the subject technology.
[0007] 1. A method for treating an aneurysm, the method comprising:
[0008] positioning a distal end of an elongated shaft in an
aneurysm cavity; [0009] releasing an occlusive member from the
elongated shaft while the distal end of the elongated shaft is
positioned within the aneurysm cavity such that the occlusive
member self-expands to assume a first expanded state in which the
occlusive member forms a first shape, wherein, in the first
expanded state, the occlusive member encloses an interior region
having a first interior volume; and [0010] delivering an embolic
element between the occlusive member and the aneurysm wall to
transform the occlusive member into a second expanded state in
which the occlusive member defines a second interior volume less
than the first interior volume, wherein the occlusive member forms
a second shape in the second expanded state that is different than
the first shape in the first expanded state.
[0011] 2. The method of any one of the previous Clauses, wherein
transforming the occlusive member into the second expanded shape
includes injecting the embolic material to urge a portion of a
sidewall of the expandable mesh in a direction away from a wall of
the aneurysm and towards the interior region of the occlusive
member.
[0012] 3. The method of any one of the previous Clauses, wherein
transforming the occlusive member into the second expanded shape
includes injecting the embolic material to invert a portion of a
sidewall of the occlusive member such that the portion is convex
towards the aneurysm wall in the first expanded state and concave
towards the aneurysm wall in the second expanded state.
[0013] 4. The method of any one of the previous Clauses, wherein
the embolic element comprises a liquid embolic.
[0014] 5. The method of any one of the previous Clauses, wherein
the embolic element comprises one or more embolization coils.
[0015] 6. The method of any one of the previous Clauses, wherein
delivering the embolic element occurs after the occlusive member is
in the first expanded state.
[0016] 7. The method of any one of the preceding Clauses, wherein
the occlusive member is a mesh.
[0017] 8. The method of any one of the preceding Clauses, wherein
the occlusive member is a braid.
[0018] 9. The method of any one of the preceding Clauses, wherein
the occlusive member is a dual-layered braid.
[0019] 10. The method of any one of the preceding Clauses, wherein
the occlusive member has a globular or generally spherical shape in
the first expanded state.
[0020] 11. The method of any one of the preceding Clauses, wherein
the occlusive member is cup or bowl-shaped in the second expanded
state.
[0021] 12. The method of any one of the preceding Clauses, wherein
the second shape is a predetermined three-dimensional shape.
[0022] 13. The method of any one of the preceding Clauses, wherein
the occlusive member forms a multi-layer braid at the neck of the
aneurysm in the second expanded state.
[0023] 14. The method of any one of the previous Clauses, wherein
the occlusive member comprises a plurality of braided filaments
that assume a pre-set, three-dimensional shape in the expanded
state.
[0024] 15. The method of any one of the previous Clauses, wherein
the occlusive member comprises a braid formed of 24, 32, 36, 48,
64, or 72 filaments.
[0025] 16. The method of any one of the previous Clauses, wherein
the occlusive member comprises a braid formed of a plurality of
wires, some or all of which have a diameter of about 0.001 inches
(0.00254 cm).
[0026] 17. The method of any one of the previous Clauses, wherein
the occlusive member comprises a braid formed of a plurality of
wires, some or all of which have the same diameter.
[0027] 18. The method of any one of the previous Clauses, wherein
the occlusive member comprises a braid formed of a plurality of
wires, at least some of which have different diameters.
[0028] 19. The method of any one of the previous Clauses, wherein
the occlusive member forms a closed, globular shape in the expanded
state, the mesh having an aperture at a distal portion.
[0029] 20. The method of any one of the previous Clauses, wherein,
in the expanded state, the occlusive member forms one of a sphere,
a prolate spheroid, or an oblate spheroid.
[0030] 21. The method of any one of the previous Clauses, wherein
the occlusive member comprises an inner layer and an outer
layer.
[0031] 22. The method of any one of the previous Clauses, wherein
the occlusive member comprises an inner layer and an outer layer
that meet at a fold at a distal portion of the occlusive
member.
[0032] 23. The method of Clause 22, wherein the expandable mesh
includes an aperture at a distal portion, the aperture being
defined by the fold.
[0033] 24. The method of any one of the previous Clauses, wherein
the occlusive member comprises an inner layer and an outer layer
that meet at a fold at a proximal portion of the occlusive
member.
[0034] 25. The method of Clause 24, wherein the expandable mesh
includes an aperture at a distal portion, the aperture being
defined by the fold.
[0035] 26. The method of any one of the previous Clauses, wherein
the occlusive member has a maximum cross-sectional dimension of 3.0
mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm,
7.5 mm, or 8.0 mm.
[0036] 27. The method of any one of the previous Clauses, wherein
the occlusive member is formed of a plurality of filaments having
first and second ends fixed at a coupler.
[0037] 28. The method of any one of the previous Clauses, wherein
the occlusive member is formed of a plurality of filaments formed
of an inner core material surrounded by an outer material.
[0038] 29. The method of Clause 28, wherein the inner core material
is a radiopaque material and the outer material is a superelastic
material.
[0039] 30. The method of any one of the previous Clauses, wherein
the occlusive member is a laser-cut tube.
[0040] 31. The method of any one of the previous Clauses, wherein
the occlusive member comprises a plurality of filaments.
[0041] 32. The method of Clause 31, wherein the filaments are
interwoven.
[0042] 33. The method of Clause 31 or Clause 32, wherein the
filaments are braided.
[0043] 34. The method of any one of Clauses 31 to 33, wherein each
of the filaments has a first end and a second end opposite the
first end, and wherein both the first and second ends of the
filaments are fixed relative to one another at a coupler.
[0044] 35. The method of Clause 34, wherein the coupler is disposed
at a distal end of the occlusive member.
[0045] 36. The method of Clause 34, wherein the coupler is disposed
at a proximal end of the occlusive member.
[0046] 37. The method of any one of Clauses 31 to 36, wherein each
of the filaments terminate at only one end of the occlusive
member.
[0047] 38. The method of Clause 37, wherein the filaments form an
opening at an end of the occlusive member opposite the only one
end.
[0048] 39. The method of Clause 38, wherein an inverted portion of
each of the filaments define the opening.
[0049] 40. The method of Clause 39, wherein the inverted portions
of the filaments are configured to move relative to one
another.
[0050] 41. The method of any one of the previous Clauses, wherein
the embolic element comprises a biopolymer and a chemical
crosslinking agent.
[0051] 42. The method of Clause 42, wherein the biopolymer includes
chitosan, a derivative of chitosan, an analog of chitosan, or a
combination thereof.
[0052] 43. The method of Clause 42 or Clause 43, wherein the
chemical crosslinking agent includes genipin, a derivative of
genipin, an analog of genipin, or a combination thereof.
[0053] 44. The method of any one of Clauses 42 to 44, wherein the
embolic element further comprises a physical crosslinking
agent.
[0054] 45. The method of Clause 45, the physical crosslinking agent
includes .beta. glycerophosphate, a derivative of .beta.
glycerophosphate, an analog of .beta. glycerophosphate, or a
combination thereof.
[0055] 46. The method of Clause 42, wherein the biopolymer includes
chitosan, a derivative of chitosan, an analog of chitosan, or a
combination thereof; [0056] the chemical crosslinking agent
includes genipin, a derivative of genipin, an analog of genipin, or
a combination thereof; and [0057] the physical crosslinking agent
includes .beta. glycerophosphate, a derivative of .beta.
glycerophosphate, an analog of .beta. glycerophosphate, or a
combination thereof.
[0058] 47. The method of any one of the preceding Clauses, wherein
the embolic element comprises a contrast agent.
[0059] 48. The method of Clause 48, wherein the contrast agent is
selected to provide diminishing radiopacity.
[0060] 49. The method of Clause 48 or Clause 49, wherein the
contrast agent includes iohexol, a derivative of iohexol, an analog
of iohexol, or a combination thereof.
[0061] 50. A method for treating an aneurysm, the method
comprising: [0062] positioning an expandable occlusive member in an
initial expanded state within an aneurysm, wherein in the initial
expanded state the expandable occlusive member provides a number of
layers across a neck of the aneurysm; and [0063] doubling the
number of layers of the occlusive device across the neck of the
aneurysm by introducing an embolic element to the aneurysm
cavity.
[0064] 51. The method of Clause 51, wherein the number of layers is
one.
[0065] 52. The method of Clause 51, wherein the number of layers is
two.
[0066] 53. The method of any one of Clauses 51 to 53, wherein the
layers are mesh layers.
[0067] 54. The method of any one of Clauses 51 to 54, wherein the
occlusive member has a first shape in the initial expanded state,
and wherein introducing the embolic element transforms the
occlusive member from the initial expanded state to a secondary
expanded state in which the occlusive member forms a second shape
different than the first shape.
[0068] 55. The method of Clause 55, wherein a volume enclosed by
the first shape is greater than a volume enclosed by the second
shape.
[0069] 56. A method for imaging treatment of an aneurysm, the
method comprising: [0070] acquiring a first image visualizing:
[0071] an occlusive member positioned within an aneurysm, the
occlusive member including a first radiopaque marker; and [0072] a
conduit having a distal portion positioned within an aneurysm, the
distal portion of the conduit including a second radiopaque marker;
and [0073] acquiring a second image in which the first radiopaque
marker is further from the second radiopaque marker than in the
first image.
[0074] 57. The method of Clause 56, wherein, in the second image,
the first radiopaque marker is positioned proximal to the second
radiopaque marker.
[0075] 58. The method of one of Clauses 56 to 57, wherein, in the
second image, the first radiopaque marker is positioned closer to a
neck of the aneurysm than in the first image.
[0076] 59. The method of any one of Clauses 56 to 58, wherein, in
the first image, the first radiopaque marker is positioned in a
distal half of the occlusive member.
[0077] 60. The method of any one of Clauses 56 to 59, wherein, in
the first image, the first radiopaque marker is positioned on a
distal-facing surface of the occlusive member.
[0078] 61. The method of any one of Clauses 56 to 60, wherein, in
the first image, the first radiopaque is positioned proximal to
second radiopaque marker.
[0079] 62. The method of any one of Clauses 56 to 61, wherein, in
the first image and in the second image, the second radiopaque
marker is disposed nearer to a dome of the aneurysm than the first
radiopaque marker.
[0080] 63. The method of any one of Clauses 56 to 62, wherein, in
the second image, a radiopaque occlusive element is visible in a
space between the first radiopaque marker and the second radiopaque
marker.
[0081] 64. The method of any one of Clauses 56 to 63, further
comprising acquiring a third image in which the first radiopaque
marker is further from the second radiopaque marker than in the
second image.
[0082] 65. The method of any one of Clauses 56 to 64, wherein
acquiring the first image and acquiring the second image each
comprises acquiring a fluoroscopic image.
[0083] 66. A method for treating an aneurysm, the method
comprising: [0084] positioning a distal end of an elongated shaft
at or near an aneurysm cavity, the distal end of the shaft
containing an occlusive member detachably coupled to an elongated
member slidably disposed within the elongated shaft, wherein a
distal end of the occlusive member is coupled to a distal end of
the elongated member and a proximal end of the occlusive member is
slidable over the elongated member; [0085] pushing the elongated
member distally from a distal opening in the elongated shaft to
pull a distal end of the occlusive member distally through the
distal opening to expel the occlusive member from the shaft and
allow the occlusive member to self-expand to a first expanded
state; [0086] while the occlusive member is in the first expanded
state, pulling the elongated member proximally to bring a distal
wall of the occlusive member towards a proximal wall of the
occlusive member such that the occlusive member forms a second
expanded state in which at least a portion of the occlusive member
is inverted; and [0087] delivering an embolic element through the
elongated member to a position between the occlusive member and the
aneurysm wall.
[0088] 67. The method of Clause 66, wherein, as the occlusive
member self-expands, a proximal end of the occlusive member slides
distally along the elongated member.
[0089] 68. The method of any one of the previous Clauses, wherein
delivering the embolic element occurs while the elongated member is
pulled proximally.
[0090] 69. The method of any one of the previous Clauses, further
comprising inverting the occlusive member at a pre-determined
longitude defined by a bending region.
[0091] 70. The method of any one of the preceding Clauses, wherein
the occlusive member is a mesh.
[0092] 71. The method of any one of the preceding Clauses, wherein
the occlusive member is a braid.
[0093] 72. The method of any one of the preceding Clauses, wherein
the occlusive member is a dual-layered braid.
[0094] 73. The method of any one of the preceding Clauses, wherein
the occlusive member has a globular or generally spherical shape in
the first expanded state.
[0095] 74. The method of any one of the preceding Clauses, wherein
the occlusive member is cup or bowl-shaped in the second expanded
state.
[0096] 75. The method of any one of the preceding Clauses, wherein
the second shape is a predetermined three-dimensional shape.
[0097] 76. The method of any one of the preceding Clauses, wherein
the occlusive member forms a multi-layer braid at the neck of the
aneurysm in the second expanded state.
[0098] 77. The method of any one of the previous Clauses, wherein
the occlusive member comprises a plurality of braided filaments
that assume a pre-set, three-dimensional shape in the expanded
state.
[0099] 78. The method of any one of the previous Clauses, wherein
the occlusive member comprises a recessed portion at its distal
portion.
[0100] 79. The method of Clause 78, wherein an opening of the
elongated member is adjacent the recessed portion such that the
embolic element is delivered within the recessed portion.
[0101] 80. A method for treating an aneurysm, the method
comprising: [0102] positioning a distal end of an elongated shaft
at or near an aneurysm cavity, the distal end of the shaft
containing an occlusive member detachably coupled to an elongated
member slidably disposed within the elongated shaft, wherein a
distal end of the occlusive member is coupled to a distal end of
the elongated member and a proximal end of the occlusive member is
slidable over the elongated member; [0103] pushing the elongated
member distally from a distal opening in the elongated shaft to
pull a distal end of the occlusive member distally through the
distal opening to expel the occlusive member from the shaft and
allow the occlusive member to self-expand to a first expanded
state; and [0104] while the occlusive member is in the first
expanded state, pulling the elongated member proximally to bring a
distal wall of the occlusive member towards a proximal wall of the
occlusive member such that the occlusive member forms a second
expanded state in which the occlusive member is collapsed on
itself.
[0105] 81. The method of Clause 80, further comprising delivering
an embolic element through the elongated member to a position
between the occlusive member and the aneurysm wall.
[0106] 82. A system comprising: [0107] an elongate shaft defining a
lumen; [0108] an elongate member slidably disposed within the lumen
of the elongate shaft, the elongate member having a proximal end
region and a distal end region, wherein the distal end region is
configured to be intravascularly position at or within an aneurysm
cavity; [0109] an occlusive member constrained within the lumen of
the shaft, the occlusive member including a proximal end portion
having an opening and a distal end portion detachably coupled to
the distal end region of the elongate member, wherein the elongate
member extends through the opening such that the [0110] wherein
pushing the elongate member from a distal opening in the elongate
shaft pulls the occlusive member distally through the distal
opening to expel the occlusive member from the shaft and allow the
occlusive member to expand to an expanded state.
[0111] 83. The system of Clause 82, further comprising an embolic
element configured to be delivered to the aneurysm cavity through
the elongate member while the elongate member is coupled to the
distal end portion of the occlusive member.
[0112] 84. The system of Clause 83, wherein the embolic element is
a liquid embolic, one or more embolic coils, or both.
[0113] 85. The system of any one of Clauses 82 to 84, wherein a
portion of the occlusive member surrounding the elongate member at
the opening is configured to slide relative to the elongate member
as the occlusive member self-expands.
[0114] 86. The system of any one of Clauses 82 to 85, wherein the
occlusive member comprises one or more preferential bending regions
about all or a portion of the circumference of the occlusive
member.
[0115] 87. The system of Clause 86, wherein all or a portion of the
one or more preferential bending regions comprise a radiopaque
material.
[0116] 88. The system of any one of Clauses 82 to 87, wherein the
expanded state is a first expanded state and the occlusive member
has a first shape in the first expanded state, and wherein, when
the occlusive member is in the first expanded state in the aneurysm
cavity and coupled to the elongate member, proximal movement of the
elongate member collapses a distal wall of the occlusive member
towards a proximal wall of the occlusive member, thereby
transforming the occlusive member into a second expanded state in
which the occlusive member has a shape different than the first
shape.
[0117] 89. A method for treating an aneurysm, the method
comprising: [0118] positioning a distal end of an elongate shaft at
or near an aneurysm cavity, the distal end of the shaft containing
an occlusive member detachably coupled to an elongated member
slidably disposed within the elongated shaft, wherein a distal end
of the occlusive member is coupled to a distal end of the elongate
member and a proximal end of the occlusive member is slidable over
the elongate member; [0119] pushing the elongate member distally
from a distal opening in the elongate shaft to pull a distal end of
the occlusive member distally through the distal opening to expel
the occlusive member from the shaft and allow the occlusive member
to self-expand to a first expanded state; [0120] while the
occlusive member is in the first expanded state, pulling the
elongate member proximally to bring a distal wall of the occlusive
member towards a proximal wall of the occlusive member such that
the occlusive member forms a second expanded state in which at
least a portion of the occlusive member is inverted; [0121] and
delivering an embolic element through the elongate member to a
position between the occlusive member and the aneurysm wall.
[0122] 90. The method of Clause 89, wherein, as the occlusive
member self-expands, a proximal end of the occlusive member slides
distally along the elongate member.
[0123] 91. The method of Clause 89 or Clause 90, wherein delivering
the embolic element occurs while the elongate member is pulled
proximally.
[0124] 92. The method of any one of Clauses 89 to 91, further
comprising inverting the occlusive member at a pre-determined
longitude defined by a bending region along the occlusive
member.
[0125] 93. The method of any one of Clauses 89 to 92, wherein the
occlusive member has a globular or generally spherical shape in the
first expanded state.
[0126] 94. The method of any one of Clauses 89 to 93, wherein the
occlusive member is cup or bowl-shaped in the second expanded
state.
[0127] 95. The method of any one of Clauses 89 to 94, wherein the
occlusive member forms a multi-layer braid at the neck of the
aneurysm in the second expanded state, the multi-layer braid
comprising a first layer corresponding to the distal wall of the
occlusive member and a second layer corresponding to the proximal
wall of the occlusive member.
[0128] 96. A method for treating an aneurysm, the method
comprising: [0129] positioning a distal end portion of an elongated
shaft at or near an aneurysm cavity, the distal end portion of the
shaft containing an occlusive member detachably coupled to an
elongated member slidably disposed within the elongated shaft,
wherein a distal end region of the occlusive member is coupled to a
distal end of the elongated member; [0130] expanding the occlusive
member within the aneurysm cavity; [0131] pulling the elongate
member proximally, thereby causing a first portion of the occlusive
member to invert onto a second portion of the occlusive member,
wherein the first and second portions meet at a circumferential
fold; [0132] pushing the elongate member distally, thereby causing
the second portion to move away from the first portion and at least
partially reversing the inversion of the occlusive member; and
[0133] delivering an embolic element through the elongate member to
a space between a distal wall of the occlusive member and a wall of
the aneurysm.
[0134] 97. The method of Clause 96, further comprising delivering
an embolic element through the elongated member to a position
between the occlusive member and the aneurysm wall.
[0135] 98. The method of Clause 96 or Clause 97, wherein pulling
the elongate member proximally occurs at a first time and the
method further comprises pulling the elongate member proximally at
a second time after the first time and after pushing the elongate
member distally, wherein pulling the elongate member proximally at
the second time brings a distal wall of the occlusive member
towards a proximal wall of the occlusive member such that the
occlusive member forms a cup or bowl shape.
[0136] 99. The method of Clause 98, wherein delivering the embolic
element occurs while the elongate member is being pulled proximally
at the second time.
[0137] 100. The method of any one of Clauses 96 to 99, wherein, as
the occlusive member expands, a proximal end region of the
occlusive member slides distally relative to the elongate
member.
[0138] 101. The method of any one of Clauses 96 to 100, further
comprising detaching the elongate member from the distal end region
of the occlusive member and withdrawing the elongate member from
the body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0139] Many aspects of the present disclosure can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily to scale. Instead, emphasis is
placed on illustrating clearly the principles of the present
disclosure.
[0140] FIG. 1A shows a perspective view of a system for treating an
aneurysm in accordance with the present technology.
[0141] FIG. 1B shows an enlarged view of a distal portion of the
treatment system of FIG. 1A in accordance with the present
technology.
[0142] FIGS. 1C and 1D are sectioned views of occlusive members in
an expanded state in accordance with the present technology.
[0143] FIG. 2 shows an embolic kit according to the present
technology.
[0144] FIGS. 3A-3G depict an example method of treating an aneurysm
with the treatment systems of the present technology.
[0145] FIGS. 4A-5B show various types of images that may be
employed to confirm and/or monitor deployment of the treatment
system of the present technology.
[0146] FIG. 6 shows a system for treating an aneurysm in accordance
with the present technology.
[0147] FIGS. 7A-7J depict an example method of treating an aneurysm
with the treatment systems of the present technology.
DETAILED DESCRIPTION
[0148] Methods for treating intracranial aneurysms in accordance
with at least some embodiments of the present technology include
positioning an expandable occlusive member within the aneurysm and
introducing an embolic element between the occlusive member and an
aneurysm wall. Introduction of the embolic element both fills space
within the aneurysm cavity and deforms the occlusive member from a
first expanded state to a second expanded state to fortify the
occlusive member at the neck of the aneurysm. Deformation of the
occlusive member from a first expanded state to a second expanded
state provides the additional advantage of giving visual
confirmation to the physician that the delivered amount of embolic
element sufficiently fills the aneurysm cavity. In addition to
providing a structural support and anchor for the embolic element,
the occlusive member provides a scaffold for tissue remodeling and
diverts blood flow from the aneurysm. Moreover, the embolic element
exerts a substantially uniform pressure on the occlusive member
towards the neck of the aneurysm, thereby pressing the portions of
the occlusive member positioned adjacent the neck against the inner
surface of the aneurysm wall such that the occlusive member forms a
complete and stable seal at the neck.
[0149] Specific details of systems, devices, and methods for
treating intracranial aneurysms in accordance with embodiments of
the present technology are described herein with reference to FIGS.
1A-7J. Although these systems, devices, and methods may be
described herein primarily or entirely in the context of treating
saccular intracranial aneurysms, other contexts are within the
scope of the present technology. For example, suitable features of
described systems, devices, and methods for treating saccular
intracranial aneurysms can be implemented in the context of
treating non-saccular intracranial aneurysms, abdominal aortic
aneurysms, thoracic aortic aneurysms, renal artery aneurysms,
arteriovenous malformations, tumors (e.g. via occlusion of
vessel(s) feeding a tumor), perivascular leaks, varicose veins
(e.g. via occlusion of one or more truncal veins such as the great
saphenous vein), hemorrhoids, and sealing endoleaks adjacent to
artificial heart valves, covered stents, and abdominal aortic
aneurysm devices among other examples. Furthermore, it should be
understood, in general, that other systems, devices, and methods in
addition to those disclosed herein are within the scope of the
present disclosure. For example, systems, devices, and methods in
accordance with embodiments of the present technology can have
different and/or additional configurations, components, procedures,
etc. than those disclosed herein. Moreover, systems, devices, and
methods in accordance with embodiments of the present disclosure
can be without one or more of the configurations, components,
procedures, etc. disclosed herein without deviating from the
present technology.
I. Overview of Systems of the Present Technology
[0150] FIG. 1A illustrates a view of a system 10 for treating
intracranial aneurysms according to one or more embodiments of the
present technology. As shown in FIG. 1A, the system 10 comprises a
treatment system 100 and an embolic kit 200 for use with one or
more components of the treatment system 100. The treatment system
100 may comprise an occlusive member 102 (shown in an expanded
state) detachably coupled to a delivery system, and the delivery
system may be configured to intravascularly position the occlusive
member 102 within an aneurysm. The embolic kit 200 may comprise one
or more substances or devices that alone or in combination form an
embolic element that is configured to co-occupy the internal volume
of the aneurysm with the occlusive member 102. In some embodiments,
the treatment system 100 may be configured to deliver the embolic
element (and/or one or more precursors thereof) to the aneurysm.
Additionally or alternatively, the system 10 may include a separate
delivery system (not shown) for delivering the embolic element
(and/or one or more precursors thereof) to the aneurysm cavity.
[0151] As shown in FIG. 1A, the treatment system 100 has a proximal
portion 100a configured to be extracorporeally positioned during
treatment and a distal portion 100b configured to be
intravascularly positioned within a blood vessel (such as an
intracranial blood vessel) at a treatment site at or proximate an
aneurysm. The treatment system 100 may include a handle 103 at the
proximal portion 100a, the occlusive member 102 at the distal
portion 100b, and a plurality of elongated shafts or members
extending between the proximal and distal portions 100a and 100b.
In some embodiments, such as that shown in FIG. 1A, the treatment
system 100 may include a first elongated shaft 109 (such as a guide
catheter or balloon guide catheter), a second elongated shaft 108
(such as a microcatheter) configured to be slidably disposed within
a lumen of the first elongated shaft 109, and an elongated member
106 configured to be slidably disposed within a lumen of the second
elongated shaft 108. In some embodiments, the treatment system 100
does not include the first elongated shaft 109 and only includes
the second elongated shaft 108.
[0152] FIG. 1B is an enlarged view of the distal portion 100b of
the treatment system 100. Referring to FIGS. 1A and 1B together,
the occlusive member 102 may be detachably coupled to a distal end
of the elongated member 106. For example, the elongated member 106
may include a first coupler 112 at its distal end, and the
occlusive member 102 may include a second coupler 114 configured to
detachably couple with the first coupler 112. The treatment system
100 may further comprise a conduit 116 extending from the handle
103 (for example, via port 110) distally to the distal portion 100b
of the treatment system 100. The conduit 116 is configured to
deliver the embolic element (and/or one or more precursors thereof)
through one or more components of the delivery system (e.g., the
first or second elongated shafts 109, 108, the elongated member
106, etc.) to a position at the exterior of the occlusive member
102. As such, the embolic element may be positioned between the
occlusive member 102 and an inner wall of the aneurysm cavity, as
described in greater detail below.
[0153] According to some embodiments, the second elongated shaft
108 is generally constructed to track over a conventional guidewire
in the cervical anatomy and into the cerebral vessels associated
with the brain and may also be chosen according to several standard
designs that are generally available. Accordingly, the second
elongated shaft 108 can have a length that is at least 125 cm long,
and more particularly may be between about 125 cm and about 175 cm
long. In some embodiments, the second elongated shaft 108 may have
an inner diameter of about 0.015 inches (0.0381 cm), 0.017 inches
(0.043 cm), about 0.021 inches (0.053 cm), or about 0.027 inches
(0.069 cm). Other designs and dimensions are contemplated.
[0154] The elongated member 106 can be movable within the first
and/or second elongated shafts 109, 108 to position the occlusive
member 102 at a desired location. The elongated member 106 can be
sufficiently flexible to allow manipulation, e.g., advancement
and/or retraction, of the occlusive member 102 through tortuous
passages. Tortuous passages can include, for example, catheter
lumens, microcatheter lumens, blood vessels, urinary tracts,
biliary tracts, and airways. The elongated member 106 can be formed
of any material and in any dimensions suitable for the task(s) for
which the system is to be employed. In some embodiments, the
elongated member 106 can comprise a solid metal wire. In some
embodiments, the elongated member 106 may comprise any other
suitable form of shaft such as an elongated tubular shaft.
[0155] In some embodiments, the elongated member 106 can comprise
stainless steel, nitinol, cobalt chrome, or other metal or alloy.
In some embodiments, the elongated member 106 can be surrounded
over some or all of its length by a coating, such as, for example,
polytetrafluoroethylene. The elongated member 106 may have a
diameter that is generally constant along its length, or the
elongated member 106 may have a diameter that tapers radially
inwardly, along at least a portion of its length, as it extends in
a distal direction.
[0156] According to several embodiments, the conduit 116 may be a
catheter or elongated shaft that is delivered separately from the
second elongated shaft 108.
[0157] A. Selected Examples of Occlusive Members
[0158] FIG. 1C is a sectioned view of the occlusive member 102,
shown in an expanded state and detached from the treatment system
100. Referring to FIGS. 1B and 1C, the occlusive member 102 may
comprise an expandable element having a low-profile or constrained
state while positioned within a catheter (such as the second
elongated shaft 108) for delivery to the aneurysm and an expanded
state in which the expandable element is configured to be
positioned within an aneurysm (such as a cerebral aneurysm).
[0159] According to some embodiments, the occlusive member 102 may
comprise a mesh 101 formed of a plurality of braided filaments that
have been heat-set to assume a predetermined shape enclosing an
interior volume 130 when the mesh 101 is in an expanded,
unconstrained state. Example shapes include a globular shape, such
as a sphere, a prolate spheroid, an oblate spheroid, and others. As
depicted in FIG. 1C, the mesh 101 may have inner and outer layers
122, 124 that have proximal ends fixed relative to one another at
the second coupler 114 and meet distally at a distal fold 128
surrounding an aperture 126. While the inner and outer layers 122,
124 are depicted spaced apart from one another along their lengths,
the inner and outer layers 122, 124 may be in contact with one
another along all or a portion of their lengths. For example, the
inner layer 122 may press radially outwardly against the outer
layer 124. In some embodiments, the occlusive member 102 may be
formed of a single layer or mesh or braid.
[0160] In some embodiments, the inner and outer layers 122, 124
have their distal ends fixed relative to one another at a distal
coupler and meet proximally at a proximal fold surrounding an
aperture. In any case, in some embodiments the conduit 116 may be
configured to be slidably positioned through some or all of the
second coupler 114, the interior volume 130 of the expanded mesh
101, and the opening 126.
[0161] The inner and outer layers 122 and 124 may conform to one
another at the distal portion (for example as shown in FIG. 1C) to
form a curved distal surface. For example, at least at the distal
portion of the occlusive member 102, the inner and outer layers 122
and 124 may extend distally and radially inwardly, towards the
aperture 126. In some embodiments, the outer and/or inner layers
122 and 124 extend distally and radially outwardly from the second
coupler 114, then extend distally and radially inwardly up to a
distal terminus of the occlusive member 102 (e.g., the fold 128).
The occlusive member 102 and/or layers thereof may be curved along
its entire length, or may have one or more generally straight
portions. In some embodiments, the curved surface transitions to a
flat or substantially flat, distal-most surface that surrounds the
aperture 126. In some embodiments, the curved surface transitions
to a distal-most surface that surrounds the aperture 126 and has a
radius of curvature that is greater than the average radius of
curvature of the rest of the occlusive member 102. Having a flat or
substantially flat distal surface, or a distal surface with a
radius of curvature that is greater than the average radius of
curvature of the rest of the occlusive member 102, may be
beneficial for delivering the embolic element 230 in that it
creates a small gap between the distal surface of the occlusive
member 102 and the dome of the aneurysm A (see, for example, FIG.
3B). In some embodiments, the surface of the occlusive member 102
surrounding the aperture 126 is curved and/or has generally the
same radius of curvature as the remainder of the occlusive member
102.
[0162] In any case, the inner layer 124 may have a shape that
substantially conforms to the shape of the outer layer 124, or the
inner and outer layers 122, 124 may have different shapes. For
example, as shown in FIG. 1D, the inner layer 122 may have a
diameter or cross-sectional dimension that is less than the outer
layer 124. Such a configuration may be beneficial in that the
embolic element 230 experiences less resistance, at least
initially, when pushing the distal wall of the occlusion member 102
downwardly towards the neck (as described in greater detail
below).
[0163] In any case, both the proximal portion and the distal
portion of the mesh 101 can form generally closed surfaces.
However, unlike at the proximal portion of the mesh 101, the
portion of the filaments at or near the fold 128 at the distal
portion of the mesh 101 can move relative to one another. As such,
the distal portion of the mesh 101 has both the properties of a
closed end and also some properties of an open end (like a
traditional stent), such as some freedom of movement of the
distal-most portions of the filaments and an opening through which
the conduit 116, a guidewire, guidetube, or other elongated member
may pass through.
[0164] In some embodiments, each of the plurality of filaments have
a first end positioned at the proximal portion of the mesh 101 and
a second end also positioned at the proximal portion of the mesh
101. Each of the filaments may extend from its corresponding first
end distally along the body of the mesh 101 to the fold 128,
invert, then extend proximally along the mesh body to its
corresponding second end at the proximal portion of the mesh 101.
As such, each of the plurality of filaments have a first length
that forms the inner layer 122 of the mesh 101, a second length
that forms the outer layer 124 of the mesh 101, and both first and
second ends fixed at the proximal portion of the mesh 101. In some
embodiments, the occlusive member 102 may comprise a mesh formed of
a single layer, or a mesh formed of three or more layers.
[0165] In some embodiments, the distal end surface of the mesh 101
is completely closed (i.e., does not include an aperture). In some
embodiments the filaments are fixed relative to the at both the
proximal and distal ends of the occlusive member 102.
[0166] The mesh 101 may be formed of metal wires, polymer wires, or
both, and the wires may have shape memory and/or superelastic
properties. The mesh 101 may be formed of 24, 32, 36, 48, 64, 72,
96, 128, or 144 filaments. The mesh 101 may be formed of a range of
filament or wire sizes, such as wires having a diameter of from
about 0.0004 inches to about 0.0020 inches, or of from about 0.0009
inches to about 0.0012 inches. In some embodiments, each of the
wires or filaments have a diameter of about 0.0004 inches, about
0.0005 inches, about 0.0006 inches, about 0.0007 inches, about
0.0008 inches, about 0.0009 inches, about 0.001 inches, about
0.0011 inches, about 0.0012 inches, about 0.0013 inches, about
0.0014 inches, about 0.0015 inches, about 0.0016 inches, about
0.0017 inches, about 0.0018 inches, about 0.0019 inches, or about
0.0020 inches. In some embodiments, all of the filaments of the
braided mesh 101 may have the same diameter. For example, in some
embodiments, all of the filaments have a diameter of about 0.001
inches. In some embodiments, some of the filaments may have
different cross-sectional diameters. For example, some of the
filaments may have a slightly thicker diameter to impart additional
strength to the braided layers. In some embodiments, some of the
filaments can have a diameter of about 0.001 inches, and some of
the filaments can have a diameter of greater than 0.001 inches. The
thicker filaments may impart greater strength to the braid without
significantly increasing the device delivery profile, with the
thinner wires offering some strength while filling-out the braid
matrix density.
[0167] The occlusive member 102 can have different shapes and sizes
in an expanded, unconstrained state. For example, the occlusive
member 102 may have a bullet shape, a barrel-shape, an egg shape, a
dreidel shape, a bowl shape, a disc shape, a cylindrical or
substantially cylindrical shape, a barrel shape, a chalice shape,
etc.
[0168] B. Selected Examples of Embolic Kits
[0169] The embolic kit 200 may include one or more precursors for
creation of a liquid embolic. For example, the embolic kit 200 may
include a first container 202 containing a first precursor material
203 (shown schematically), a second container 204 containing a
second precursor material 205 (also shown schematically), and a
mixing device 206 suitable for mixing the first and second
precursor materials 203, 205. The mixing device 206 can include
mixing syringes 208 (individually identified as mixing syringes
208a, 208b) and a coupler 210 extending between respective exit
ports (not shown) of the mixing syringes 208. The mixing syringes
208a, 208b each include a plunger 212 and a barrel 214 in which the
plunger 212 is slidably received.
[0170] The embolic kit 200 can further include an injection syringe
216 configured to receive a mixture of the first and second
precursor materials 203, 205 and deliver the mixture to a proximal
portion 100b of the treatment assembly 100. The injection syringe
216 can include a barrel 220, an exit port 222 at one end of the
barrel 220, and a plunger 224 slidably received within the barrel
220 via an opposite end of the barrel 220. The handle 103 of the
treatment system 100 may have a coupler configured to form a secure
fluidic connection between the lumen and the exit port 222 of the
injection syringe 216.
[0171] The first and second precursor materials 203, 205 can
include a biopolymer and a chemical crosslinking agent,
respectively. The chemical crosslinking agent can be selected to
form covalent crosslinks between chains of the biopolymer. In some
embodiments, the biopolymer of the first precursor material 203
includes chitosan or a derivative or analog thereof, and the
chemical crosslinking agent of the second precursor material 205
includes genipin or a derivative or analog thereof. Other suitable
crosslinking agents for use with chitosan include glutaraldehyde,
functionalized polyethylene glycol, and derivatives and analogs
thereof. In other embodiments, the biopolymer of the first
precursor material 203 can include collagen or a derivative or
analog thereof, and the chemical crosslinking agent of the second
precursor material 205 can include hexamethylene diisocyanate or a
derivative or analog thereof. Alternatively or in addition, genipin
or a derivative or analog thereof can be used as a chemical
crosslinking agent for a collagen-based biopolymer. In still other
embodiments, the biopolymer of the first precursor material 203 and
the chemical crosslinking agent of the second precursor material
205 can include other suitable compounds alone or in
combination.
[0172] Mixing the biopolymer of the first precursor material 203
and the chemical crosslinking agent of the second precursor
material 205 can initiate chemical crosslinking of the biopolymer.
After the first and second precursor materials 203, 205 are mixed,
chemical crosslinking of the biopolymer occurs for enough time to
allow the resulting embolic element 230 be delivered to the
aneurysm before becoming too viscous to move through the lumen of
the conduit 116. In addition, the period of time during which
chemical crosslinking of the biopolymer occurs can be short enough
to reach a target deployed viscosity within a reasonable time
(e.g., in the range of 10-60 minutes; or at most 40 minutes, 30
minutes, 20 minutes, or 10 minutes) after delivery. The target
deployed viscosity can be high enough to cause an agglomeration of
the embolic element 230 to remain within the internal volume of the
aneurysm without reinforcing the neck.
[0173] In at least some cases, the biopolymer has a non-zero degree
of chemical crosslinking within the first precursor material 203
before mixing with the chemical crosslinking agent. This can be
useful, for example, to customize the curing window for the embolic
element 230 so that it corresponds well with an expected amount of
time needed to deliver the material to the aneurysm. The degree of
chemical crosslinking of the biopolymer within the first precursor
material 203 before mixing with the chemical crosslinking agent,
the ratio of the biopolymer to the chemical crosslinking agent,
and/or one or more other variables can be selected to cause the
embolic element 230 to have a viscosity suitable for delivery to
the aneurysm via the lumen of the conduit 116 for a suitable period
of time (e.g., a period within a range from 10 minutes to 40
minutes) after mixing of the first and second precursor materials
203, 205. In at least some cases, the first and second precursor
materials 203, 205 are mixed in proportions that cause a weight
ratio of the biopolymer to the chemical crosslinking agent in the
resulting embolic element 230 to be within a range from 10:1 to
100:1, such as from 10:1 to 30:1, or from 15:1 to 50:1, or from
15:1 to 25:1. In a particular example, the first and second
precursor materials 203, 205 are mixed in proportions that cause a
weight ratio of the biopolymer to the chemical crosslinking agent
in the resulting embolic element 230 to be 30:1.
[0174] Use of a biopolymer instead of an artificial polymer in the
first precursor material 203 may be advantageous because
biopolymers tend to be more readily bioabsorbed than artificial
polymers and/or for other reasons. Furthermore, use of a chemical
crosslinking agent instead of a physical crosslinking agent (i.e.,
a crosslinking agent that forms noncovalent crosslinks between
chains of the biopolymer) in the second precursor material 205 may
be advantageous because chemically crosslinked polymers tend to be
more cohesive than physically crosslinked polymers and/or for other
reasons. In the context of forming a tissue scaffold within an
aneurysm, high cohesiveness of the embolic element 230 may be more
important than it is in other contexts to secure the cured embolic
element 230 within the aneurysm 302. For example, high cohesiveness
of the embolic element 230 may reduce or eliminate the possibility
of a piece of the embolic element 230 breaking free and entering a
patient's intracerebral blood stream during delivery.
[0175] The first and second precursor materials 203, 205 may
include other components and/or the system 200 may include other
precursor materials intended for mixing with the first and second
precursor materials 203, 205. For example, the first, second,
and/or another precursor material may include a physical
crosslinking agent. The presence of a physical crosslinking agent
may be useful to form physical crosslinks that complement chemical
crosslinks from the chemical crosslinking agent. The combination of
chemical and physical crosslinks may enhance the cohesiveness of
the embolic element 230. Suitable physical crosslinking agents for
use with chitosan-based biopolymers include .beta.
glycerophosphate, mannitol, glucose, and derivatives and analogs
thereof. In these and other cases, the embolic element 230 may
include multiple chemical crosslinking agents and/or multiple
physical crosslinking agents.
[0176] A contrast agent is another component that may be added to
the precursor materials. The presence of a contrast agent within
the embolic element 230 can be useful to visualize delivery of the
embolic element 230 using fluoroscopy. One problem with using
conventional platinum coils in intracranial aneurysms is that the
persistent radiopacity of the coils tends to interfere with
visualizing other aspects of the treatment in follow-up imaging.
For example, the presence of platinum coils within an aneurysm may
make it difficult or impossible to detect by fluoroscopy the
presence of blood-carried contrast agent that would otherwise
indicate recanalization. In at least some embodiments of the
present technology, a contrast agent within the embolic element 230
is selected to provide radiopacity that diminishes over time. For
example, the contrast agent may initially be radiopaque to
facilitate delivery of the embolic element 230 and then become less
radiopaque to facilitate follow-up imaging. In a particular
example, the first, second, and/or another precursor material
includes iohexol or a derivative or analog thereof as a suitable
contrast agent.
[0177] In animal studies, the liquid embolics of the present
technology were shown to provide (a) complete or nearly complete
volumetric filling of the aneurysm internal volume, and (b)
complete or nearly complete coverage of the aneurysm neck with new
endothelial tissue. These features, among others, are expected to
result in a lower recanalization rate than that of platinum coil
treatments and faster aneurysm occlusion than that of flow
diverters. Furthermore, the injectable scaffold material is
expected to be bioabsorbed and thereby reduced in volume over time.
Thus, unlike platinum coils, the injectable scaffold is expected to
have little or no long-term mass effect. Furthermore, the
injectable scaffold material can be configured to have diminishing
radiopacity; therefore, when so configured it will not interfere
future CT and MRI imaging and procedures. Embodiments of the
present technology can have these and/or other features and
advantages relative to conventional counterparts whether or not
such features and advantages are described herein.
[0178] In some embodiments, the embolic kit 200 and/or embolic
element 230 may be any embolic or occlusive device, such as one or
more embolic coils, polymer hydrogel(s), polymer fibers, mesh
devices, or combinations thereof. The embolic kit 200 may include
one or more precursors that, once mixed together, form the embolic
element 230 that remains within the aneurysm. In some embodiments,
the embolic kit 200 may include the embolic element pre-mixed.
II. Selected Methods for Treating Aneurysms
[0179] FIGS. 3A-3G depict an example method for treating an
aneurysm A with the systems 10 of the present technology. To begin,
a physician may intravascularly advance the second elongated shaft
108 towards an intracranial aneurysm (or other treatment location
such as any of those described herein) with the occlusive member
102 in a low-profile state. A distal portion of the second
elongated shaft 108 may be advanced through a neck N of the
aneurysm A to locate a distal opening of the second elongated shaft
108 within an interior cavity of the aneurysm A. The elongated
member 106 may be advanced distally relative to the second
elongated shaft 108 to push the occlusive member 102 through the
opening at the distal end of the second elongated shaft 108,
thereby releasing the occlusive member 102 from the shaft 108 and
allowing the occlusive member 102 to self-expand into a first
expanded state.
[0180] FIG. 3A shows the occlusive member 102 in a first expanded
state, positioned in an aneurysm cavity and still coupled to the
elongated member 106. As shown in FIG. 3A, in the first expanded
state, the occlusive member 102 may assume a predetermined shape
that encloses an internal volume 130 (see FIG. 1C). In this first
expanded state, the occlusive member 102 may generally conform to
the shape of the aneurysm A. As illustrated in FIG. 3B with the
occlusive member 102 and delivery system shown in cross-section,
the conduit 116 may be advanced through the internal volume 130 of
the occlusive member 102 such that a distal opening of the conduit
116 is at or distal to the aperture 126 at the distal portion of
the occlusive member 102. The embolic element 230 may be delivered
through the conduit 116 to a space between the occlusive member 102
and an inner surface of the aneurysm wall W.
[0181] In some embodiments, the method includes mixing the first
and second precursor materials 203, 205 (FIG. 2) to form the
embolic element 230. Mixing of the first and second precursor
materials 203, 205 may occur prior to introducing the embolic
element 230 to the treatment system 100 and/or during delivery of
the embolic element through the conduit 116 to the aneurysm. In a
particular example, the first precursor material 203 is loaded into
one of the barrels 214, the second precursor materials 205 is
loaded into the other barrel 214, and the mixing syringes 208 are
coupled via the coupler 210. To mix the first and second precursor
materials 203, 205, the plungers 212 are alternately depressed,
thereby causing the first and second precursor materials 203, 205
to move repeatedly from one barrel 214 to the other barrel 214.
After suitably mixing the precursor materials, the resulting
embolic element 230 can be loaded into the barrel 220 of the
injection syringe 216. The injection syringe 216 may then be
coupled to a proximal end of the conduit 116 to deliver the embolic
element 230 through the conduit 116 and into the aneurysm A. As the
embolic element 230 passes through the lumen of the conduit 116,
chemical crosslinking of the biopolymer can continue to occur.
[0182] Still with reference to FIG. 3B, as the embolic element 230
is delivered between the dome of the aneurysm A and the distal
portion 132 of the wall of the occlusive member 102, pressure
builds between the aneurysm wall W and the occlusive member 102. As
shown in the progression of FIGS. 3B-3D, when the forces on the
occlusive member 102 reach a threshold level, the embolic element
230 pushes the distal wall 132 downwardly towards the neck N of the
aneurysm A. The embolic element 230 exerts a substantially uniform
pressure across the distal surface of the occlusive member 102 that
collapses the occlusive member 102 inwardly on itself such that the
rounded distal wall 132 transitions from concave towards the neck N
of the aneurysm A to convex towards the neck N. The pressure and
inversion of the distal portion of the wall 132 creates an annular
fold 136 that defines the distal-most edge of the occlusive member
102. As the occlusive member 102 continues to invert, the position
of the fold 136 moves towards the neck N, which continues until a
distal-most half of the occlusive member 102 has inverted. In some
embodiments, the occlusive member 102 may include one or more
portions configured to preferentially flex or bend such that the
occlusive member 102 folds at a desired longitude (for example, as
discussed in greater detail below with respect to FIGS. 5-7J.
Moreover, as the occlusive member 102 collapses, a distance between
the wall at the distal portion 132 and the wall at the proximal
portion decreases, and thus the internal volume 130 of the
occlusive member 102 also decreases. As the occlusive member 102
collapses, the conduit 116 may be held stationary, advanced
distally, and/or retracted proximally.
[0183] During and after delivery of the embolic element 230, none
or substantially none of the embolic element 230 migrates through
the pores of the occlusive member 102 and into the internal volume
130. Said another way, all or substantially all of the embolic
element 230 remains at the exterior surface or outside of the
occlusive member 102. Compression of the occlusive member with the
embolic element 230 provides a real-time "leveling" or
"aneurysm-filling indicator" to the physician under single plane
imaging methods (such as fluoroscopy) so that the physician can
confirm at what point the volume of the aneurysm is completely
filled. Additional details regarding devices, systems, and methods
for monitoring and/or confirming deployment are described below
with reference to FIGS. 4A-5B. It is beneficial to fill as much
space in the aneurysm as possible, as leaving voids within the
aneurysm sac may cause delayed healing and increased risk of
aneurysm recanalization and/or rupture. While the scaffolding
provided by the occlusive member 102 across the neck helps
thrombosis of blood in any gaps and healing at the neck, the
substantial filling of the cavity prevents rupture acutely and does
not rely on the neck scaffold (i.e., the occlusive member 102).
Confirmation of complete or substantially complete aneurysm filling
under single plane imaging cannot be provided by conventional
devices.
[0184] Once delivery of the embolic element 230 is complete, the
conduit 116 may be withdrawn. In some embodiments, the embolic
element 230 may fill greater than 40% of the aneurysm sac volume.
In some embodiments, the embolic element 230 may fill greater than
50% of the aneurysm sac volume. In some embodiments, the embolic
element 230 may fill greater than 60% of the aneurysm sac volume.
In some embodiments, the embolic element may fill greater than 65%,
70%, 75%, 80%, 85%, or 90% of the aneurysm sac volume.
[0185] FIG. 3E shows a second expanded state of the occlusive
member 102, shown in cross-section, with the embolic element 230
occupying the remaining volume of the aneurysm A. FIG. 3F shows the
occlusive member 102 in full with the embolic element 230 removed
so the second shape of the occlusive member 102 is visible. As
shown, the embolic element 230 may be delivered until the occlusive
member 102 is fully-collapsed such that the occlusive member 102
has substantially no internal volume.
[0186] In the second expanded state, the occlusive member 102 may
form a bowl shape that extends across the neck of the aneurysm A.
The wall of the occlusive member 102 at the distal portion may now
be positioned in contact with or immediately adjacent the wall of
the occlusive member 102 at the proximal portion. The distal wall
132 may be in contact with the proximal wall 134 along all or
substantially all of its length. In some embodiments, the distal
wall 132 may be in contact with the proximal wall 134 along only a
portion of its length, while the remainder of the length of the
distal wall 132 is in close proximity--but not in contact with--the
proximal wall 134.
[0187] Collapse of the occlusive member 102 onto itself, towards
the neck N of the aneurysm, may be especially beneficial as it
doubles the number of layers across the neck and thus increases
occlusion at the neck N. For example, the distal wall 132
collapsing or inverting onto the proximal wall 134 may decrease the
porosity of the occlusive member 102 at the neck N. In those
embodiments where the occlusive member 102 is a mesh or braided
device such that the distal wall 132 has a first porosity and the
proximal wall 134 has a second porosity, deformation of the distal
wall 132 onto or into close proximity within the proximal wall 134
decreases the effective porosity of the occlusive member 102 over
the neck N. The resulting multi-layer structure thus has a lower
porosity than the individual first and second porosities. Moreover,
the embolic element 230 along the distal wall 132 provides
additional occlusion. In some embodiments, the embolic element 230
completely or substantially completely occludes the pores of the
adjacent layer or wall of the occlusion member 102 such that blood
cannot flow past the embolic element 230 into the aneurysm cavity.
It is desirable to occlude as much of the aneurysm as possible, as
leaving voids of gaps can allow blood to flow in and/or pool, which
may continue to stretch out the walls of aneurysm A. Dilation of
the aneurysm A can lead to recanalization and/or herniation of the
occlusive member 102 and/or embolic element 230 into the parent
vessel and/or may cause the aneurysm A to rupture. Both conditions
can be fatal to the patient.
[0188] In those embodiments where the wall of the occlusive member
102 comprises an inner and outer layer, the deformed or second
shape of the occlusive member 102 forms four layers over the neck N
of the aneurysm A In those embodiments where the wall of the
occlusive member 102 comprises a single layer, the deformed or
second shape of the occlusive member 102 forms two layers over the
neck N of the aneurysm A As previously mentioned, the neck coverage
provided by the doubled layers provides additional surface area for
endothelial cell growth, decreases the porosity of the occlusive
member 102 at the neck N (as compared to two layers or one layer),
and prevents herniation of the embolic element 230 into the parent
vessel. During and after delivery, the embolic element 230 exerts a
substantially uniform pressure on the occlusive member 102 towards
the neck N of the aneurysm A, thereby pressing the portions of the
occlusive member 102 positioned adjacent the neck against the inner
surface of the aneurysm wall such that the occlusive member 102
forms a complete and stable seal at the neck N.
[0189] As shown in FIG. 3G, the first coupler 112 may be detached
from the second coupler 114 and the elongated member 106 and second
elongated shaft 108 may be withdrawn, thereby leaving the occlusive
member 102 and embolic element 230 implanted within the aneurysm
A.
[0190] Over time natural vascular remodeling mechanisms and/or
bioabsorption of the embolic element 230 may lead to formation of a
thrombus and/or conversion of entrapped thrombus to fibrous tissue
within the internal volume of the aneurysm A. These mechanisms also
may lead to cell death at a wall of the aneurysm and growth of new
endothelial cells between and over the filaments or struts of the
occlusive device 102. Eventually, the thrombus and the cells at the
wall of the aneurysm may fully degrade, leaving behind a
successfully remodeled region of the blood vessel.
[0191] In some embodiments, contrast agent can be delivered during
advancement of the occlusive member 102 and/or embolic element 230
in the vasculature, deployment of the occlusive member 102 and/or
embolic element 230 at the aneurysm A, and/or after deployment of
the occlusive member 102 and/or embolic element 230 prior to
initiation of withdrawal of the delivery system. The contrast agent
can be delivered through the second elongated shaft 108, the
conduit 116, or through another catheter or device commonly used to
delivery contrast agent. The aneurysm (and devices therein) may be
imaged before, during, and/or after injection of the contrast
agent, and the images may be compared to confirm a degree of
occlusion of the aneurysm.
[0192] According to some aspects of the technology, the system 10
may comprise separate first and second elongated shafts (e.g.,
microcatheters) (not shown), the first dedicated to delivery of the
embolic element, and the second dedicated to the delivery of the
occlusive member. In example methods of treating an aneurysm, the
first elongated shaft may be intravascularly advanced to the
aneurysm and through the neck such that that a distal tip of the
first elongated shaft is positioned within the aneurysm cavity. In
some embodiments, the first elongated shaft may be positioned
within the aneurysm cavity such that the distal tip of the shaft is
near the dome of the aneurysm.
[0193] The second elongated shaft containing the occlusive member
(such as occlusive member 102) may be intravascularly advanced to
the aneurysm and positioned within the aneurysm cavity adjacent the
first elongated shaft. The occlusive member may then be deployed
within the aneurysm sac. As the occlusive member is deployed, it
pushes the first elongated shaft outwardly towards the side of the
aneurysm, and when fully deployed the occlusive member holds or
"jails" the first elongated shaft between an outer surface of the
occlusive member and the inner surface of the aneurysm wall.
[0194] The embolic element (such as embolic element 230) may then
be delivered through the first elongated shaft to a position
between the inner surface of the aneurysm wall and the outer
surface of the occlusive member. For this reason, it may be
beneficial to initially position the distal tip of the first
elongated shaft near the dome (or more distal surface) of the
aneurysm wall. This way, the "jailed" first elongated shaft will be
secured by the occlusive member such that the embolic element
gradually fills the open space in the aneurysm sac between the dome
and the occlusive member. As described elsewhere herein, the
filling of the embolic element pushes and compresses the occlusive
member against the tissue surrounding the aneurysm neck as the
space in the sac above the occlusive member is being filled from
the dome to the neck. Also as described elsewhere herein, the
compression of the occlusive member with the embolic element
provides a "leveling or aneurysm filling indicator" which is not
provided by conventional single plane imaging methods. The filling
of the embolic element may complete, for example, when it occupies
about 50-80% of the volume of the aneurysm.
III. Selected Devices, Systems, and Methods for Monitoring
Deployment
[0195] Proper deployment of the embolic element 230 and the
occlusive member 102 can be monitored and/or confirmed using one or
more medical imaging techniques, such as fluoroscopy. FIGS. 4A-5B
illustrate examples of various types of fluoroscopic images that
may be employed by a physician at different stages of deployment to
monitor the position of the occlusive member 102 within the
aneurysm A, monitor the degree of filling of the aneurysm A with
the embolic element 230, and/or confirm a degree of occlusion of
the aneurysm A by the deployed system. As described in greater
detail below, the devices and systems of the present technology may
be configured to provide unique visual indicators that provide
confirmation to the physician via one or more medical imaging
techniques regarding a degree of occlusion of the aneurysm. As
described in greater detail below, the visual indicators may
include a particular change in shape of all or a portion of the
occlusive member 102, a particular change in relative position of
one or more radiopaque markers on the occlusive member 102 and/or
delivery system (such as the conduit 116), a particular change in
shape of the embolic element 230, and others.
[0196] Although the following discussion is made with reference to
the two-dimensional images shown in FIGS. 4A-5B, the systems and
methods of the present technology can be employed with
three-dimensional imaging techniques. Moreover, FIGS. 4A-5B
represent a two-dimensional image in which only a slice of the
aneurysm (and devices therein) is visible. While in some cases the
inner and outer layers of the occlusive member 102 (when such are
present) may be distinguishable from one another in the
radiographic image, in the present example the layers appear as one
thick layer. As used herein, "proper deployment" or "successful
deployment" may refer to (a) complete (e.g., greater than 80%) or
substantially complete (e.g., greater than 50%) filling of the
aneurysm A with the embolic element 230, (b) complete or
substantially complete inversion or collapse of the occlusive
member 102 onto itself over the neck N of the aneurysm A, (c) or
both.
[0197] The occlusive member 102 may include one or more radiopaque
markers, such as markers 402, 404, 406, and 114 (referred to
collectively as "markers 401") shown in FIGS. 4A-4C. The markers
401 may be disposed about the occlusive member 102 in a specific
spatial arrangement such that relative movement of the markers is
indicative of a degree of stage of deployment of the occlusive
member 102 and/or embolic element 230. The markers 401 may be
positioned at any location along the occlusive member 102. For
example, the occlusive member 102 may include one or more
radiopaque markers 402 at or along its distal wall 132 (only one
shown for ease of illustration), one or more radiopaque markers 404
at or along its proximal wall 134 (only one shown for ease of
illustration), and one or more radiopaque markers 406 at or along
the intermediate portion of the wall (only one shown for ease of
illustration). Moreover, the coupler 114 of the occlusive member
102 may be radiopaque. The markers 401 may be positioned at one,
some, or all of the layers of the occlusive member 102 (at least in
those embodiments where the occlusive member 102 includes multiple
layers). In some embodiments, the individual markers 401 may
comprise a radiopaque band or clip coupled to the one or more
struts, filaments, wires, etc. of the occlusive member 102. In some
embodiments, the individual markers 401 may comprise a radiopaque
material coated on or otherwise incorporated into the wall of the
occlusive member 102. The individual markers 401 may have the same
or different shapes, lengths, and/or profiles.
[0198] In some embodiments, in addition to or instead of having one
or more markers 401, the occlusive member 102 itself may be
partially or completely formed of a radiopaque material, such as
one or more radiopaque wires. In the example depicted in FIGS.
4A-4C, the occlusive member 102 is formed of a radiopaque material
and also includes radiopaque markers 402, 404, 406. The occlusive
member 102 is formed of a plurality of drawn-filled tube ("DFT")
wires, which comprise a core formed of a radiopaque material (such
as platinum) surrounded by an outer non-radiopaque material (at
least relative to the core material). The markers 402, 404, 406 are
completely formed of a radiopaque material and thus have a higher
density of radiopaque material. As such, the markers 402, 404, 406
appear darker than the occlusive member 102 in the images. In some
embodiments, the occlusive member 102 may have a radiopacity that
is different than the radiopacity of one or more of the markers
402, 404, 406 such that the wall of the occlusive member 102 wall
and the marker(s) 406 can be distinguished from one another on the
radiographic image. The wall of the occlusive member 102 may be
more or less radiopaque than one or more of the markers 402, 404,
406.
[0199] In some embodiments, one or more components of the delivery
system may include one or more radiopaque markers. For example, the
conduit 116 may include one or more radiopaque markers positioned
along its length. In the embodiment depicted in FIGS. 4A-4C, the
conduit 116 may include a radiopaque marker 400 positioned at or
near its distal end. The conduit 116 may have one or more
additional markers (not shown) positioned along its length, such as
along the length of the conduit 116 that extends through the
interior volume 130 of the occlusive member 102.
[0200] As shown in FIG. 4A, when the occlusive member 102 is first
deployed (e.g., allowed to self-expand) within the aneurysm, the
radiopaque marker(s) 402, 404, 406 of the occlusive member 102 will
be in a first position relative to one another, and to the
radiopaque marker(s) of the conduit 116. By way of example, markers
402 and 404 are separated by a first distance d.sub.1 when the
occlusive member 102 is first deployed. As the embolic element 230
is conveyed through the conduit 116 and into the aneurysm sac, the
occlusive member 102 may deform as described previously with
respect to FIGS. 3A-3G. This deformation can cause the radiopaque
marker(s) 401 carried by the occlusive member 102 to move to a
second position relative to one another. For example, the physician
may confirm progression of deployment by observing that markers 402
and 404 are now separated by a distance d.sub.2. The radiopaque
marker(s) 401 may also move relative to the radiopaque marker(s)
400 of the conduit 116, which may remain in the same or
substantially the same place within the aneurysm. By comparing an
image of the radiopaque markers 400 and/or 401 in the first
relative positions and an image of the radiopaque markers 400
and/or 401 in the second relative positions, a clinician can
visually confirm that the embolic element 230 has filled a certain
percentage of the aneurysm A.
[0201] For example, according to some aspects of the technology,
confirmation of sufficient filling of the aneurysm (i.e., 50% or
greater) may be indicated by one or more distal wall markers 402
moving into close proximity to one or more proximal wall markers
404 and/or touching one or more proximal wall markers 404. Because
the embolic element 230 applies a generally uniform pressure across
the distal wall 132 and pushes downwardly towards the neck N as it
fills in the space between the occlusive member 102 and the
aneurysm wall, the movement of one or more distal wall markers 402
to a position adjacent a proximal wall marker 404 indicates to a
physician that the aneurysm A is substantially filled (e.g., 50% or
greater) with the embolic element 230. This relative positioning
also indicates that the distal wall 132 is now providing additional
occlusion at the neck N of the aneurysm and that the occlusive
member 102 is in its second expanded shape. In some embodiments,
the coupler 114 may be used as the proximal indicator instead of or
in addition to the one or more proximal markers 404.
[0202] In some embodiments, confirmation of sufficient filling of
the aneurysm (i.e., 50% or greater) may be indicated by one or more
distal wall markers 402 moving away from the conduit marker 400 (or
marker affixed to another component of the delivery system) by a
predetermined distance. For example, when the occlusive member 102
is in the first expanded state or shape (FIG. 4A) the distal wall
marker 402 may be adjacent the conduit marker 400. In the second
expanded state or shape (FIG. 4C), the distal wall marker 402 may
be separated from the conduit marker 400 by a distance that is
generally equivalent to a diameter D of the occlusive member 102 in
its expanded state while initially positioned in the aneurysm A. As
explained above, such relative positioning of one or more distal
wall markers 402 and conduit marker 400 indicates to a physician
that the aneurysm A is substantially filled (e.g., 50% or greater)
with the embolic element 230. This relative positioning also
indicates that the distal wall 132 is now providing additional
occlusion at the neck N of the aneurysm and that the occlusive
member 102 is in its second expanded shape.
[0203] In some embodiments, one or more intermediate markers 406
may be used to confirm and/or monitor deployment. For example, one
or more intermediate markers 406 may be positioned at or near a
desired inversion plane of the occlusive member 102. In the present
example using a generally spherical occlusive member 102 that
deforms to assume a bowl shape, the inversion plane is at or near a
midline of the occlusive member 102 in its expanded state. This is
because, in a fully inverted state, the distal half of the
occlusive member 102 will lie within/conform to the proximal half
of the occlusive member 102 (as shown in FIG. 4C). As such, the
midline of the occlusive member 102 is the desired plane of
inversion. The occlusive member 102 may be radiopaque (as shown in
FIGS. 4A-4C), but to a lesser extent than the intermediate
marker(s) 406 such that the occlusive member 102 wall and the
marker(s) 406 can be distinguished from one another on the
radiographic image. As such, an image showing the top edge 136
(FIG. 4C) of the occlusive member 102 adjacent or at the
intermediate marker(s) 406 may indicate that the aneurysm A is
substantially filled (e.g., 50% or greater) with the embolic
element 230. This relative positioning also indicates that the
distal wall 132 is now providing additional occlusion at the neck N
of the aneurysm and that the occlusive member 102 is in its second
expanded shape.
[0204] The change in shape of the occlusive member 102 and/or
change in position of different portions of the occlusive member
102 relatively to one another may also indicate proper deployment.
As previously discussed, the occlusive member 102 assumes a first
expanded shape when initially deployed and has a second expanded
shape after deformation by the embolic element 230. In several
embodiments, the second expanded shape represents a partially or
completely inverted from of the first expanded shape, which can be
confirmed on the radiographic image by observing the changing
outline of the occlusive member 102. For instance, in the present
example where the occlusive member 102 has a first expanded shape
that is generally spherical, an image showing a C-shape (as shown
in FIG. 4C) may indicate that the desired filling and/or deployment
is complete. In a three-dimensional image, the second expanded
shape may have a bowl shape. In some embodiments, confirmation of
complete or substantially complete deployment may be indicated by
the distal wall 500 being within a predetermined distance of the
proximal wall 502.
[0205] In some embodiments, proper deployment may be confirmed by
observing a distance between the inverted wall (here, distal wall
132) and the relatively stationary wall (here, proximal wall 134).
As shown in FIG. 4C, when the distal wall 132 collapses down onto
or near the proximal wall 134, the occlusive member 102 presents on
the image as having twice the thickness at the proximal portion.
Moreover, as the occlusive member 102 inverts, the density of the
radiopaque material doubles, and thus the doubled-over portions of
the occlusive member 102 appear darker on the image.
[0206] As shown in FIGS. 5A and 5B, in some embodiments, certain
portions of the occlusive member 102 may be coated with a
radiopaque material such that change in shape or orientation of
those portions indicates a desired position of the occlusive member
102. For example, as shown in FIG. 5A, a distal-most half 500 of
the occlusive member 102 may be coated with a radiopaque material
while a proximal-most half 502 may not be coated or may otherwise
be less radiopaque than the distal half 500. As such, confirmation
of complete or substantially complete deployment may be indicated
by the more radiopaque distal wall 500 being adjacent the proximal
wall 502. For example, confirmation of complete or substantially
complete deployment may be indicated by the distal wall 500 being
within a predetermined distance of the proximal wall 502.
Confirmation may also be gleaned from the distal wall 500 changing
in shape from flat or convex (towards the dome) of the aneurysm A
to concave.
[0207] A shape of the embolic element 230 may also provide an
indication of deployment progress. For example, the shape of the
lower (closer to the neck N) perimeter of the aneurysm A can be
indicative of a degree of filling of the aneurysm with the embolic
element 230 and/or degree of deformation of the occlusive member
102. As most aneurysms have a generally spherical or globular
shape, a lower boundary of the embolic element 230 may have a
decreasing radius of curvature as more is injected and more of the
occlusive member 102 inverts. For example, in FIG. 4B, when the
aneurysm A is partially filled with the embolic element 230 and the
occlusive member 102 is only partially collapsed or inverted, the
distal wall 132 has a first radius of curvature. In FIG. 4C, when
the aneurysm A is substantially completely or completely filled,
the distal wall 132 has a radius of curvature less than the radius
of curvature of the distal wall 132 in the partially deformed
state.
[0208] Additionally or alternatively, the degree of deployment of
the occlusive member 102 and/or degree of filling of the aneurysm A
can be further determined by injecting contrast into the parent
blood vessel and imaging the aneurysm to determine how much of the
contrast enters the aneurysm cavity. The shape of the
[0209] The devices, systems, and methods of the present technology
may be particularly beneficial over conventional devices for
two-dimensional imaging. In two dimensional imaging (such as
fluoroscopy), the image may reflect only a slice or elevational
view of the aneurysm (and device or substance therein). As such,
any voids or gaps in filling may not be apparent in the slice
because the image slice does not transect the void within the
aneurysm A, or the cross-section or elevational view of the
stagnated area may take on different shapes depending on how the
image is observed. A physician may have to take a plurality of
images to determine a general amount of filling in the aneurysm. In
contrast, the occlusion members 102 of the present technology have
a unique shape that dynamically adjusts to the introduction of an
embolic element 230 in a predictable, measurable way that indicates
a degree of filling of the embolic element 230 in a single
two-dimensional radiographic image.
[0210] The devices, systems, and methods disclosed herein include
confirming and/or observing various stages of deployment of the
system in an aneurysm, including complete or substantially complete
deployment, using one, some, or all of the methods disclosed
above.
IV. Selected Embodiments
[0211] FIG. 6 shows the distal portion of a treatment system 600
for treating an aneurysm in accordance with the present technology.
The treatment system 600 may be a portion of a system that also
includes an embolic kit (not shown). The embolic kit may be
substantially the same as the embolic kit 200 described above. As
shown in FIG. 6, the treatment system 600 may comprise an occlusive
member 602 (shown in an expanded state) detachably coupled to a
delivery system, and the delivery system may be configured to
intravascularly position the occlusive member 602 within an
aneurysm. In some embodiments, the treatment system 600 may be
configured to deliver the embolic element (and/or one or more
precursors thereof) to the aneurysm. Additionally or alternatively,
the system may include a separate delivery system (not shown) for
delivering the embolic element (and/or one or more precursors
thereof) to the aneurysm cavity.
[0212] Similar to treatment system 100, the treatment system 600
has a proximal portion (not shown) configured to be
extracorporeally positioned during treatment and a distal portion
600b configured to be intravascularly positioned within a blood
vessel (such as an intracranial blood vessel) at a treatment site
at or proximate an aneurysm. The treatment system 600 may include a
handle at the proximal portion, the occlusive member 602 at the
distal portion 600b, and a plurality of elongated shafts or members
extending between the proximal and distal portions. In some
embodiments, such as that shown in FIG. 6, the treatment system 600
may include a first elongated shaft (such as a guide catheter or
balloon guide catheter) (not depicted), a second elongated shaft
108 (such as a microcatheter) configured to be slidably disposed
within a lumen of the first elongated shaft, and an elongated
member 616 configured to be slidably disposed within a lumen of the
second elongated shaft 108. In contrast to the delivery system of
treatment system 100, the elongated member 616 also functions as
the conduit. As such, the treatment system 600 does not include a
separate elongated member 616 and conduit. In some embodiments, the
treatment system 600 does not include the first elongated shaft and
only includes the second elongated shaft 108.
[0213] A distal end of the occlusive member 602 may be detachably
coupled to a distal end of the elongated member 616. For example,
the elongated member 616 may include a first coupler 612 at its
distal end, and the occlusive member 602 may include a second
coupler 614 configured to detachably couple with the first coupler
612. The elongated member 616 may be configured to deliver the
embolic element (and/or one or more precursors thereof) through one
or more components of the delivery system (e.g., the first or
second elongated shafts 109, 108) to a position at the exterior of
the occlusive member 602. As such, the embolic element may be
positioned between the occlusive member 102 and an inner wall of
the aneurysm cavity, as described in greater detail below.
[0214] According to some embodiments, the second elongated shaft
108 is generally constructed to track over a conventional guidewire
in the cervical anatomy and into the cerebral vessels associated
with the brain and may also be chosen according to several standard
designs that are generally available. Accordingly, the second
elongated shaft 108 can have a length that is at least 125 cm long,
and more particularly may be between about 125 cm and about 175 cm
long. In some embodiments, the second elongated shaft 108 may have
an inner diameter of about 0.015 inches (0.0381 cm), 0.017 inches
(0.043 cm), about 0.021 inches (0.053 cm), or about 0.027 inches
(0.069 cm). Other designs and dimensions are contemplated.
[0215] The elongated member 616 can be movable within the first
and/or second elongated shafts to position the occlusive member 602
at a desired location. The elongated member 616 can be sufficiently
flexible to allow manipulation, e.g., advancement and/or
retraction, of the occlusive member 602 through tortuous passages.
Tortuous passages can include, for example, catheter lumens,
microcatheter lumens, blood vessels, urinary tracts, biliary
tracts, and airways. The elongated member 616 can be formed of any
material and in any dimensions suitable for the task(s) for which
the system is to be employed. In some embodiments, the elongated
member 616 may comprise any other suitable form of shaft such as an
elongated tubular shaft.
[0216] In some embodiments, the elongated member 616 can comprise
stainless steel, nitinol, cobalt-chrome, or other metal or alloy.
In some embodiments, the elongated member 616 can be surrounded
over some or all of its length by a coating, such as, for example,
polytetrafluoroethylene. The elongated member 616 may have a
diameter that is generally constant along its length, or the
elongated member 616 may have a diameter that tapers radially
inwardly, along at least a portion of its length, as it extends in
a distal direction.
[0217] C. Selected Examples of Occlusive Members
[0218] Referring still to FIG. 5, the occlusive member 602 may
comprise an expandable element having a low-profile or constrained
state while positioned within a catheter (such as the second
elongated shaft 108) for delivery to the aneurysm and an expanded
state in which the expandable element is configured to be
positioned within an aneurysm (such as a cerebral aneurysm).
According to some embodiments, the occlusive member 602 may
comprise a mesh formed of a plurality of braided filaments that
have been heat-set to assume a predetermined shape enclosing an
interior volume 130 when the mesh is in an expanded, unconstrained
state. Example shapes include a globular shape, such as a sphere, a
prolate spheroid, an oblate spheroid, and others. As depicted in
the cross-sectional view in FIG. 6, the mesh may have inner and
outer layers 622, 624 that have distal ends fixed relative to one
another at the second coupler 614 and meet distally at a proximal
fold 628 surrounding a proximal aperture 626. While the inner and
outer layers 622, 624 are depicted spaced apart from one another
along their lengths, the inner and outer layers 622, 624 may be in
contact with one another along all or a portion of their lengths.
For example, the inner layer 622 may press radially outwardly
against the outer layer 624. In some embodiments, the occlusive
member 602 may be formed of a single layer or mesh or braid.
[0219] The elongated shaft 616 may be configured to be slidably
positioned through some or all of the second coupler 614, the
interior volume 130 of the expanded mesh, and the opening 626.
Because the occlusive member 602 is coupled to the elongated shaft
616 at its distal end (e.g., via the first and second couplers 612,
614), axial movement of the elongated shaft 616 causes axial
movement of at least the distal portion of the occlusive member
602. The proximal portion of the occlusive member 602 remains free
to slide along the elongated shaft 616 via the proximal aperture
626. In some embodiments, when the occlusive member 602 is loaded
in the elongated member 616, the occlusive member 602 is positioned
around the elongated member 616, between the elongated member 616
and the second elongated shaft 108.
[0220] The inner and outer layers 622 and 624 may conform to one
another at the distal portion (for example as shown in FIG. 5) to
form a curved distal surface. For example, at least at the distal
portion of the occlusive member 602, the inner and outer layers 622
and 624 may extend distally and radially inwardly, towards the
aperture 626. In some embodiments, the outer and/or inner layers
622 and 624 extend distally and radially outwardly from the fold
628 at the aperture 626, then extend distally and radially inwardly
up to ridge, then proximally to the second coupler 614 to create a
detent or recess 604 at the distal end of the occlusive member 602.
For example, the distal surface of the occlusive member 602 may be
concave towards the dome of the aneurysm. The distal recess 604 may
be beneficial for delivering the embolic element 230 in that it
creates a small gap between the distal surface of the occlusive
member 602 and the dome of the aneurysm A (see, for example, FIG.
7B).
[0221] The occlusive member 602 and/or layers thereof may be curved
along its entire length, or may have one or more generally straight
portions. In some embodiments, the curved surface transitions to a
flat or substantially flat, distal-most surface that surrounds the
aperture 626. In some embodiments, the curved surface transitions
to a distal-most surface that surrounds the aperture 626 and has a
radius of curvature that is greater than the average radius of
curvature of the rest of the occlusive member 602. Having a flat or
substantially flat distal surface, or a distal surface with a
radius of curvature that is greater than the average radius of
curvature of the rest of the occlusive member 602, may be
beneficial for delivering the embolic element 230 in that it
creates a small gap between the distal surface of the occlusive
member 602 and the dome of the aneurysm A. In some embodiments, the
surface of the occlusive member 602 surrounding the aperture 626 is
curved and/or has generally the same radius of curvature as the
remainder of the occlusive member 602.
[0222] In any case, the inner layer 624 may have a shape that
substantially conforms to the shape of the outer layer 624, or the
inner and outer layers 622, 624 may have different shapes. For
example, the inner layer 622 may have a diameter or cross-sectional
dimension that is less than the outer layer 624 (for example, as
shown in FIG. 1D). Such a configuration may be beneficial in that
the embolic element 230 experiences less resistance, at least
initially, when pushing the distal wall of the occlusion member 602
downwardly towards the neck (as described in greater detail
below).
[0223] In any case, both the proximal portion and the distal
portion of the mesh can form generally closed surfaces. However,
unlike at the second coupler 614 at the distal portion of the mesh,
the portion of the filaments at or near the fold 628 at the
proximal portion of the mesh can move relative to one another. As
such, the distal portion of the mesh has both the properties of a
closed end and also some properties of an open end (like a
traditional stent), such as some freedom of movement of the
proximal-most portions of the filaments and an opening through
which the elongated shaft 616, a guidewire, guidetube, or other
elongated member may pass through.
[0224] In some embodiments, each of the plurality of filaments have
a first end positioned at the distal portion of the mesh and a
second end also positioned at the distal portion of the mesh (for
example, at the second coupler 614). Each of the filaments may
extend from its corresponding first end distally to ridge, then
proximally along the body of the mesh to the fold 628, invert, then
extend distally along the mesh body to the ridge, then proximally
to its corresponding second end at the distal portion of the mesh.
As such, each of the plurality of filaments have a first length
that forms the inner layer 622 of the mesh, a second length that
forms the outer layer 624 of the mesh, and both first and second
ends fixed at the distal portion of the mesh. In some embodiments,
the occlusive member 602 may comprise a mesh formed of a single
layer, or a mesh formed of three or more layers.
[0225] In some embodiments, the proximal and/or distal end surface
of the mesh is completely closed (i.e., does not include an
aperture). In some embodiments the filaments are fixed relative to
the at both the proximal and distal ends of the occlusive member
602 and the elongated member 616 is configured to be slidably
disposed through each of the proximal and distal hubs.
[0226] In some embodiments, the occlusive member 602 and/or mesh
may include a preferential bending region 604 at which the
occlusive member 602 and/or mesh is configured to preferentially
flex or bend when subject to inverting forces (such as that exerted
by the embolic element 230, as described in greater detail below).
The bending region 604 may form a continuous band around the
circumference of the occlusive member 602, or it may be at select
locations about the circumference of the occlusive member 602, all
located at generally the same axial location along the mesh. In
those embodiments in which the occlusive member 602 comprises
multiple layers, none, some, or all of the layers may include the
bending region 604. The bending region 604 may comprise, for
example, a thinned portion of the mesh that is generally weaker
than the surrounding portions and thus more likely to bend under
stress. The bending region 604 may also be formed by heat setting
the mesh in the inverted or collapsed state such that the mesh
preferentially inverts at the desired level.
[0227] The mesh forming the occlusive member 602 may be formed of
metal wires, polymer wires, or both, and the wires may have shape
memory and/or superelastic properties. The mesh may be formed of
24, 32, 36, 48, 64, 72, 96, 128, or 144 filaments. The mesh may be
formed of a range of filament or wire sizes, such as wires having a
diameter of from about 0.0004 inches to about 0.0020 inches, or of
from about 0.0009 inches to about 0.0012 inches. In some
embodiments, each of the wires or filaments have a diameter of
about 0.0004 inches, about 0.0005 inches, about 0.0006 inches,
about 0.0007 inches, about 0.0008 inches, about 0.0009 inches,
about 0.001 inches, about 0.0011 inches, about 0.0012 inches, about
0.0013 inches, about 0.0014 inches, about 0.0015 inches, about
0.0016 inches, about 0.0017 inches, about 0.0018 inches, about
0.0019 inches, or about 0.0020 inches. In some embodiments, all of
the filaments of the braided mesh may have the same diameter. For
example, in some embodiments, all of the filaments have a diameter
of about 0.001 inches. In some embodiments, some of the filaments
may have different cross-sectional diameters. For example, some of
the filaments may have a slightly thicker diameter to impart
additional strength to the braided layers. In some embodiments,
some of the filaments can have a diameter of about 0.001 inches,
and some of the filaments can have a diameter of greater than 0.001
inches. The thicker filaments may impart greater strength to the
braid without significantly increasing the device delivery profile,
with the thinner wires offering some strength while filling-out the
braid matrix density.
[0228] The occlusive member 602 can have different shapes and sizes
in an expanded, unconstrained state. For example, the occlusive
member 602 may have a bullet shape, a barrel-shape, an egg shape, a
dreidel shape, a bowl shape, a disc shape, a cylindrical or
substantially cylindrical shape, a barrel shape, a chalice shape,
etc.
[0229] D. Selected Examples of Embolic Kits
[0230] The embolic kit for use with the treatment system shown in
FIGS. 6-7J may be substantially similar to the embolic kit 200
described above.
[0231] E. Selected Methods of Deployment
[0232] FIGS. 7A-7J depict an example method of treating an aneurysm
with the treatment systems of the present technology. To begin, a
physician may intravascularly advance the second elongated shaft
108 towards an intracranial aneurysm (or other treatment location
such as any of those described herein) with the occlusive member
602 in a low-profile state. As shown in FIG. 7A, the second
elongated shaft 108 may be positioned at or just proximal of the
neck. Alternatively, a distal portion of the second elongated shaft
108 may be advanced through a neck N of the aneurysm A to locate a
distal opening of the second elongated shaft 108 within an interior
cavity of the aneurysm A. In either case, the elongated member 616
may be advanced distally through the neck N and into the aneurysm
cavity (if not already in the aneurysm cavity), thereby pulling the
distal end of the occlusive member 602 with it. As the occlusive
member 602 is released from its constrained state within the second
elongated shaft 108, the occlusive member 602 expands towards the
first expanded state, as shown in FIG. 7B. In the first expanded
state, the occlusive member 602 may assume a predetermined shape
that encloses an internal volume 130. In this first expanded state,
the occlusive member 602 may generally conform to the shape of the
aneurysm A.
[0233] Prior to delivering the embolic agent 230, the physician may
pull the elongated member 616 proximally to check the positioning
of the occlusive member 602 in the aneurysm A. As depicted in FIGS.
7B and 7C, for example, the elongated member 616 may be pulled
proximally to force the distal wall towards the neck N and proximal
wall. Because of the bending region(s) 603, the occlusive member
602 may preferentially fold and develop a distal edge at the
bending regions 603. The ability to check the position of the
occlusive member 602 in its collapsed state before delivering the
embolic element 230 may be beneficial, especially in wide-necked
aneurysms, as the initial approach into the aneurysm may be too
steep such that the distal edge 136 (see FIG. 7C), once the
occlusive member 602 is fully collapsed or inverted, is near or
aligned with the neck of the aneurysm A. In those cases, the
occlusive member 602 may not fully cover the neck N, and thus will
not be sufficiently anchored in the aneurysm A. It will be
appreciated that the elongated member 616 may be used to check the
positioning of the occlusive member 602 even in those embodiments
where the occlusive member 602 does not have a bending region
603.
[0234] As shown in FIGS. 7D-7H, the embolic element 230 may be
delivered through the elongated member 616 to a space between the
occlusive member 602 and an inner surface of the aneurysm wall W.
In some embodiments, the method includes mixing the first and
second precursor materials 203, 205 (FIG. 2) to form the embolic
element 230. Mixing of the first and second precursor materials
203, 205 may occur prior to introducing the embolic element 230 to
the treatment system 100 and/or during delivery of the embolic
element through the elongated member 616 to the aneurysm. In a
particular example, the first precursor material 203 is loaded into
one of the barrels 214, the second precursor materials 205 is
loaded into the other barrel 214, and the mixing syringes 208 are
coupled via the coupler 210. To mix the first and second precursor
materials 203, 205, the plungers 212 are alternately depressed,
thereby causing the first and second precursor materials 203, 205
to move repeatedly from one barrel 214 to the other barrel 214.
After suitably mixing the precursor materials, the resulting
embolic element 230 can be loaded into the barrel 220 of the
injection syringe 216. The injection syringe 216 may then be
coupled to a proximal end of the elongated member 616 to deliver
the embolic element 230 through the elongated member 616 and into
the aneurysm A. As the embolic element 230 passes through the lumen
of the elongated member 616, chemical crosslinking of the
biopolymer can continue to occur.
[0235] Still with reference to FIGS. 7D-7H, as the embolic element
230 is delivered between the dome of the aneurysm A and the distal
portion of the wall of the occlusive member 602, pressure builds
between the aneurysm wall W and the occlusive member 602. When the
forces on the occlusive member 602 reach a threshold level, the
embolic element 230 pushes the distal wall downwardly towards the
neck N of the aneurysm A. If desired, the elongated member 616 may
be pulled proximally while the embolic element 230 is delivered
and/or between different injections of the embolic element 230,
which encourages inversion of the occlusive member 602.
[0236] As detailed above, the embolic element 230 exerts a
substantially uniform pressure across the distal surface of the
occlusive member 602 that collapses the occlusive member 602
inwardly on itself (with or without the help of the elongated
member 616). The pressure and inversion of the distal portion of
the wall creates an annular fold 136 that defines the distal-most
edge of the occlusive member 602. As the occlusive member 602
continues to invert, the position of the fold moves towards the
neck N, which continues until a distal-most half of the occlusive
member 602 has inverted. Moreover, as the occlusive member 602
collapses, a distance between the wall at the distal portion and
the wall at the proximal portion decreases, and thus the internal
volume 130 of the occlusive member 602 also decreases. As the
occlusive member 602 collapses, the elongated member 616 may be
held stationary, advanced distally, and/or retracted
proximally.
[0237] During and after delivery of the embolic element 230, none
or substantially none of the embolic element 230 migrates through
the pores of the occlusive member 602 and into the internal volume
130. Said another way, all or substantially all of the embolic
element 230 remains at the exterior surface or outside of the
occlusive member 602. Compression of the occlusive member with the
embolic element 230 provides a real-time "leveling" or
"aneurysm-filling indicator" to the physician under single plane
imaging methods (such as fluoroscopy) so that the physician can
confirm at what point the volume of the aneurysm is completely
filled. Additional details regarding devices, systems, and methods
for monitoring and/or confirming deployment are described above
with reference to FIGS. 4A-5B. It is beneficial to fill as much
space in the aneurysm as possible, as leaving voids within the
aneurysm sac may cause delayed healing and increased risk of
aneurysm recanalization and/or rupture. While the scaffolding
provided by the occlusive member 602 across the neck helps
thrombosis of blood in any gaps and healing at the neck, the
substantial filling of the cavity prevents rupture acutely and does
not rely on the neck scaffold (i.e., the occlusive member 602).
Confirmation of complete or substantially complete aneurysm filling
under single plane imaging cannot be provided by conventional
devices.
[0238] Once delivery of the embolic element 230 is complete, the
elongated member 616 may be withdrawn. In some embodiments, the
embolic element 230 may fill greater than 40% of the aneurysm sac
volume. In some embodiments, the embolic element 230 may fill
greater than 50% of the aneurysm sac volume. In some embodiments,
the embolic element 230 may fill greater than 60% of the aneurysm
sac volume. In some embodiments, the embolic element may fill
greater than 65%, 70%, 75%, 80%, 85%, or 90% of the aneurysm sac
volume.
[0239] FIG. 71 shows a second expanded state of the occlusive
member 602, shown in cross-section, with the embolic element 230
occupying the remaining volume of the aneurysm A. As shown, the
embolic element 230 may be delivered until the occlusive member 602
is fully-collapsed such that the occlusive member 602 has
substantially no internal volume. In the second expanded state, the
occlusive member 602 may form a bowl shape that extends across the
neck of the aneurysm A. The wall of the occlusive member 602 at the
distal portion may now be positioned in contact with or immediately
adjacent the wall of the occlusive member 602 at the proximal
portion. In some instances, because of the presence of the second
coupler 614, a small gap may remain between portions of the distal
wall and the proximal wall when the occlusive member 602 is in its
second or collapsed state.
[0240] Collapse of the occlusive member 602 onto itself, towards
the neck N of the aneurysm, may be especially beneficial as it
doubles the number of layers across the neck and thus increases
occlusion at the neck N. For example, the distal wall 132
collapsing or inverting onto the proximal wall may decrease the
porosity of the occlusive member 602 at the neck N. In those
embodiments where the occlusive member 602 is a mesh or braided
device such that the distal wall has a first porosity and the
proximal wall has a second porosity, deformation of the distal wall
onto or into close proximity within the proximal wall decreases the
effective porosity of the occlusive member 602 over the neck N. The
resulting multi-layer structure thus has a lower porosity than the
individual first and second porosities. Moreover, the embolic
element 230 along the distal wall provides additional occlusion. In
some embodiments, the embolic element 230 completely or
substantially completely occludes the pores of the adjacent layer
or wall of the occlusion member 602 such that blood cannot flow
past the embolic element 230 into the aneurysm cavity. It is
desirable to occlude as much of the aneurysm as possible, as
leaving voids of gaps can allow blood to flow in and/or pool, which
may continue to stretch out the walls of aneurysm A. Dilation of
the aneurysm A can lead to recanalization and/or herniation of the
occlusive member 602 and/or embolic element 230 into the parent
vessel and/or may cause the aneurysm A to rupture. Both conditions
can be fatal to the patient.
[0241] In those embodiments where the wall of the occlusive member
602 comprises an inner and outer layer, the deformed or second
shape of the occlusive member 602 forms four layers over the neck N
of the aneurysm A In those embodiments where the wall of the
occlusive member 602 comprises a single layer, the deformed or
second shape of the occlusive member 602 forms two layers over the
neck N of the aneurysm A As previously mentioned, the neck coverage
provided by the doubled layers provides additional surface area for
endothelial cell growth, decreases the porosity of the occlusive
member 602 at the neck N (as compared to two layers or one layer),
and prevents herniation of the embolic element 230 into the parent
vessel. During and after delivery, the embolic element 230 exerts a
substantially uniform pressure on the occlusive member 602 towards
the neck N of the aneurysm A, thereby pressing the portions of the
occlusive member 602 positioned adjacent the neck against the inner
surface of the aneurysm wall such that the occlusive member 602
forms a complete and stable seal at the neck N.
[0242] In some embodiments, the elongated member 616 may be moved
proximally and distally to move the distal wall of the occlusive
member 602 to re-distribute the embolic element 230 around the
occlusive member 602 and the aneurysm wall. As a result, the
occlusive member 602 will be locked and prevent migration after
treatment. In this case, the occlusive member 602 may not need to
fill the sac completely.
[0243] As shown in FIGS. 71-7J, the first coupler 612 may be
detached from the second coupler 614 and the elongated member 616
and second elongated shaft 108 may be withdrawn, thereby leaving
the occlusive member 602 and embolic element 230 implanted within
the aneurysm A.
[0244] Over time natural vascular remodeling mechanisms and/or
bioabsorption of the embolic element 230 may lead to formation of a
thrombus and/or conversion of entrapped thrombus to fibrous tissue
within the internal volume of the aneurysm A. These mechanisms also
may lead to cell death at a wall of the aneurysm and growth of new
endothelial cells between and over the filaments or struts of the
occlusive device 602. Eventually, the thrombus and the cells at the
wall of the aneurysm may fully degrade, leaving behind a
successfully remodeled region of the blood vessel.
[0245] In some embodiments, contrast agent can be delivered during
advancement of the occlusive member 602 and/or embolic element 230
in the vasculature, deployment of the occlusive member 602 and/or
embolic element 230 at the aneurysm A, and/or after deployment of
the occlusive member 602 and/or embolic element 230 prior to
initiation of withdrawal of the delivery system. The contrast agent
can be delivered through the second elongated shaft 108, the
elongated member 616, or through another catheter or device
commonly used to delivery contrast agent. The aneurysm (and devices
therein) may be imaged before, during, and/or after injection of
the contrast agent, and the images may be compared to confirm a
degree of occlusion of the aneurysm.
CONCLUSION
[0246] The descriptions of embodiments of the technology are not
intended to be exhaustive or to limit the technology to the precise
form disclosed above. Where the context permits, singular or plural
terms may also include the plural or singular term, respectively.
Although specific embodiments of, and examples for, the technology
are described above for illustrative purposes, various equivalent
modifications are possible within the scope of the technology, as
those skilled in the relevant art will recognize. For example,
while steps are presented in a given order, alternative embodiments
may perform steps in a different order. The various embodiments
described herein may also be combined to provide further
embodiments.
[0247] Moreover, unless the word "or" is expressly limited to mean
only a single item exclusive from the other items in reference to a
list of two or more items, then the use of "or" in such a list is
to be interpreted as including (a) any single item in the list, (b)
all of the items in the list, or (c) any combination of the items
in the list. Additionally, the term "comprising" is used throughout
to mean including at least the recited feature(s) such that any
greater number of the same feature and/or additional types of other
features are not precluded. It will also be appreciated that
specific embodiments have been described herein for purposes of
illustration, but that various modifications may be made without
deviating from the technology. Further, while advantages associated
with certain embodiments of the technology have been described in
the context of those embodiments, other embodiments may also
exhibit such advantages, and not all embodiments need necessarily
exhibit such advantages to fall within the scope of the technology.
Accordingly, the disclosure and associated technology can encompass
other embodiments not expressly shown or described herein.
* * * * *