U.S. patent application number 15/434548 was filed with the patent office on 2017-06-08 for implantable flow diverter.
This patent application is currently assigned to Cook Medical Technologies LLC. The applicant listed for this patent is Cook Medical Technologies LLC. Invention is credited to Aidan Furey.
Application Number | 20170156844 15/434548 |
Document ID | / |
Family ID | 48700761 |
Filed Date | 2017-06-08 |
United States Patent
Application |
20170156844 |
Kind Code |
A1 |
Furey; Aidan |
June 8, 2017 |
IMPLANTABLE FLOW DIVERTER
Abstract
A flow diverter for implantation into a patient's vessel
includes a distal annular support element and a proximal annular
support element, the proximal and distal support elements
supporting a longitudinally twisted diverter element. The flow
diverter is designed to be disposed within a vessel and to impart a
rotational or twisting motion to the flow of blood passing
therethrough, thereby to reduce the pressure of blood at the center
of the vessel. Such flow diversion can reduce the pressure of blood
impinging upon an aneurysm at a bifurcation downstream of the
vessel. The device can be particularly useful for the treatment of
aneurysms occurring at the bifurcation between the basilar artery
and the posterior cerebral arteries.
Inventors: |
Furey; Aidan; (Copenhagen,
DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cook Medical Technologies LLC |
Bloomington |
IN |
US |
|
|
Assignee: |
Cook Medical Technologies
LLC
|
Family ID: |
48700761 |
Appl. No.: |
15/434548 |
Filed: |
February 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14276448 |
May 13, 2014 |
|
|
|
15434548 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2210/0014 20130101;
A61B 17/12145 20130101; A61F 2230/0091 20130101; A61B 17/12113
20130101; A61F 2250/0012 20130101; A61F 2/91 20130101; A61F
2002/068 20130101; A61F 2/06 20130101 |
International
Class: |
A61F 2/06 20060101
A61F002/06; A61B 17/12 20060101 A61B017/12; A61F 2/91 20060101
A61F002/91 |
Foreign Application Data
Date |
Code |
Application Number |
May 14, 2013 |
GB |
GB1308652.5 |
Claims
1. A method of treating or preventing an aneurysm at a bifurcation
in a circulatory system, the method comprising: implanting an
endoluminal flow diverter in a blood vessel upstream of the
bifurcation to divert blood flow, the endoluminal flow diverter
comprising a proximal support at a proximal end of the diverter and
a distal support at a distal end of the diverter, the endoluminal
flow diverter defining a longitudinal axis therethrough, the
endoluminal flow diverter comprising a panel disposed between and
connected to the proximal and distal supports, the panel having a
helical twist formed therein about the longitudinal axis.
2. The method of claim 1, wherein the panel twists by an angle of
about 90 degrees between the proximal and distal supports.
3. The method of claim 1, wherein the panel is formed of a sheet of
material.
4. The method of claim 1, wherein the proximal and distal supports
are each ring-shaped.
5. The method of claim 4, wherein the proximal and distal supports
are radially compressible.
6. The method of claim 4, wherein the proximal and distal supports
in a radially expanded state define a device diameter, the device
diameter being substantially equal to the diameter of the blood
vessel.
7. The method of claim 6, wherein the panel extends across the
device diameter of the endoluminal flow diverter.
8. The method of claim 1, wherein the panel is of uniform
thickness.
9. The method of claim 1, wherein the panel twists uniformly about
the longitudinal axis.
10. The method of claim 1, wherein at least one of the proximal
support and the distal support is a stent.
11. The method of claim 1, comprising implanting the endoluminal
flow diverter into the basiliar artery.
12. The method of claim 11, wherein the endoluminal flow diverter
is implanted adjacent a bifurcation of posterior cerebral
arteries.
13. A method of treating or preventing an aneurysm at a bifurcation
of a pair of posterior cerebral arteries, the method comprising:
implanting in a basiliar artery an endoluminal flow diverter
upstream of the bifurcation to divert blood flow, the endoluminal
flow diverter comprising a proximal support at a proximal end of
the diverter and a distal support at the distal end of the
diverter, the endoluminal flow diverter defining a longitudinal
axis therethrough, the endoluminal flow diverter comprising a panel
disposed between and connected to the proximal and distal supports,
the panel having a helical twist of about 90 degrees formed therein
about the longitudinal axis.
14. The method of claim 13, wherein the proximal and distal
supports in a radially expanded state define a device diameter, the
device diameter being substantially equal to the diameter of the
basiliar artery.
15. The method of claim 14, wherein the panel extends across the
device diameter of the endoluminal flow diverter.
16. The method of claim 13, wherein blood exits the endoluminal
flow diverter with substantially constant pressure across a
diameter of the basiliar artery.
17. The method of claim 13, wherein the panel is formed of a sheet
of material.
18. The method of claim 13, wherein the proximal and distal
supports are each ring-shaped.
19. The method of claim 18, wherein the proximal and distal
supports are radially compressible.
20. The method of claim 13, wherein the panel is of uniform
thickness.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation from U.S. patent
application Ser. No. 14/276,448, filed May 13, 2014 which claims
the benefit of priority under 35 U.S.C. .sctn.119(a) to Great
Britain Patent Application No. 1308652.5, filed May 14, 2013, which
is incorporated by reference here in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to an implantable medical
device, in particular for diverting flow within the vessel of a
patient.
BACKGROUND ART
[0003] Many factors contribute to the formation of saccular
aneurysms, particularly neural aneurysms. One of the major
contributors is wall shear stress (WSS), which in addition to
hypertension leads to a reduction in the elastic tissue of the
tunica media, thereby contributing to the formation of the
aneurysm. The effect of wall shear stress is heightened at certain
anatomical geometries such as bifurcations, and for instance at the
point where the basilar artery (BA) divides into the posterior
cerebral arteries (PCA).
[0004] It is known to try to treat aneurysms by filling the
aneurysmal sac with a filler such as a prosthetic coil. The
methodology behind the use of prosthetic coils is to establish a
hard thrombus formation within the sac of the aneurysm as a means
of isolating the aneurysm wall from the flow of blood. While this
can be effective in the treatment of many types of aneurysm, it is
less effective when the aneurysm occurs at a bifurcation or
trifurcation, such as at the base of the basilar artery.
[0005] It is also known to close off the entrance to the aneurysmal
sac or to divert the flow of fluid therefrom, but known devices are
not general suitable for treatment of aneurysms at the base of the
basilar artery.
[0006] Examples of devices for treating aneurysms can be found in
US-2002/0179166, US-2002/0198591, US-2003/0100945, US-2010/0106180
and WO-2012/102919.
SUMMARY OF THE INVENTION
[0007] The present disclosure seeks to provide improved treatment
of aneurysms, in particular an implantable flow diverter and method
of diverting flow from an aneurysm.
[0008] According to an aspect of the present invention, there is
provided an endoluminal flow diverter that comprises a central
axis, a pair of supports, and a diverter element. The central axis
runs through a diameter of the device and along a longitudinal
direction. The device further comprises a pair of supports being a
proximal and distal support spaced in the longitudinal direction
along a length of the device. The device further comprises a
diverter element being disposed between and supported by the
proximal and distal supports.
[0009] The diverter element comprises a panel being twisted in the
longitudinal direction and extending across the diameter, wherein
the panel twists by an angle of about 90 degrees between the
proximal and distal supports.
[0010] The flow diverter has a structure which enables it to divert
the flow of blood within a vessel, in particular to reduce the flow
at the central portion of the vessel by causing the pressure of
blood to even out across substantially the entire width of the
vessel. When disposed, for example, at the base of the basilar
artery, that is by the posterior cerebral arteries, this has the
effect of reducing the pressure of blood flow to the vessel wall at
the bifurcation and opposite the basilar artery. This can reduce
the pressure of blood into an aneurysmal sac and therefore assist
in the treatment of such an aneurysm.
[0011] Advantageously, the panel is formed of a sheet of material.
The panel is preferably substantially impermeable, that it has a
structure which acts as a barrier to blood therethrough such that
all or substantially all of any blood impinging on the panel is
diverted by the panel. In some embodiments the panel may include
perforations or slots therein. The slots or perforations can
increase the ability of the panel to twist, or over twist, so as to
compress the device radially for deployment purposes. The slots or
perforations are, though, preferably small enough to retain the
barrier effect of the panel, that is to prevent or substantially
flow of fluid through the panel. The, panel provides a surface
within which the perforations or slots are disposed, the surface
providing a barrier to blood therethrough.
[0012] Preferably, the panel extends substantially across the
diameter of the device. It may extend across the entirety of the
diameter of the device or almost across its entirety, any shortfall
being taken up in practice by the conformability of the vessel
wall.
[0013] Preferably, the panel is of substantially uniform thickness.
In practice, it is preferred that the panel is of thin
construction, which will have little or no effect on the overall
blood pressure, that it will not cause an increase in blood
pressure as a result of vessel constriction, which is a
characteristic of some implantable medical devices. In the
preferred embodiment, the panel extends across the central axis of
the device.
[0014] Advantageously, the panel twists uniformly in helical manner
in the longitudinal direction of the device. Preferably, the panel
twists in the longitudinal direction of the device by an angle of
around 90 degrees between the proximal and distal supports. It has
been found that this feature provides optimal flow diversion. In an
embodiment, the panel is substantially rectangular.
[0015] Preferably, the proximal and distal supports are
ring-shaped. They may be separate from one another, although in
other embodiments they may be connected to one another.
[0016] Also described is a method of diverting fluid flow in a
vessel including the following steps. A user deploys in a vessel an
endoluminal flow diverter as described above. Deployment of the
flow diverter causes blood flow in the vessel to be diverted by
twisting the flow in the vessel.
[0017] Advantageously the panel extends across the central axis of
the device, the method providing for flow in the center of the
vessel to be diverted. In the preferred embodiment, the method
reduces the flow of fluid in the center of the vessel and most
preferably evens the flow of fluid across the width of the
vessel.
[0018] Other features are disclosed in the description of the
preferred embodiments of the invention which follows. It is to be
understood that all such features are applicable to all embodiments
disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective view of an embodiment of flow
diverter;
[0020] FIGS. 2 and 3 are side elevational views of the flow
diverter;
[0021] FIG. 4 is a plane view of the flow diverter;
[0022] FIG. 5 is a perspective view of another embodiment of flow
diverter;
[0023] FIG. 6 is a perspective view of another embodiment of flow
diverter;
[0024] FIG. 7 is a perspective view of another embodiment of flow
diverter;
[0025] FIG. 8 is a perspective view of another embodiment of flow
diverter;
[0026] FIG. 9 is a schematic diagram of typical fluid flow in the
basilar artery;
[0027] FIG. 10 is a view in which an aneurysm has formed at the
bifurcation with the left and right posterior cerebral
arteries;
[0028] FIG. 11 is a view in which the aneurysm sac has been filled
with an embolization coil; and
[0029] FIG. 12 is a view in which a flow diverter has been deployed
in the basilar artery.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Described below are various embodiments of flow diverter for
diverting flow within a patient's vessel. The term flow diverter as
used herein encompasses the guiding of the flow of blood within a
vessel, in particular to alter the pressure profile across the
diameter of the vessel and in the preferred embodiments to reduce
the pressure flow at the center of the vessel and preferably so as
to even out the flow pressure across the diameter of the
vessel.
[0031] As will be appreciated from the disclosure of the preferred
embodiments set out below and in the accompanying drawings, these
provide a flow diverter which has the same or substantially the
same cross-sectional area at the proximal and distal ends of the
device, that is at the inlet and outlet of the device. As a result
of this, there is no change in the overall volume of fluid passing
through the flow diverter and no overall change in pressure of
fluid passing through the diverter. Experimental data has shown
that the preferred embodiments of flow diverter disclosed herein
are able to effect a tenfold decrease in pressure within an
aneurysm. As a result, there is no flow or virtually no flow of
fluid within the aneurysm.
[0032] The preferred embodiments are described in connection with a
flow diverter intended for implantation in the basilar artery and
in particular adjacent to the bifurcation with the posterior
cerebral arteries. Therefore, the various dimensions of the device
disclosed below are chosen to suit the dimensions of the basilar
artery. It is to be understood, however, that the teachings herein
can be applied in the diversion of the flow in any vessel of a
patient and not just the basilar artery and that it is also not
restricted solely to application with aneurysms at bifurcations or
elsewhere. It will be appreciated that the dimensions of the device
will differ for different vessel sizes.
[0033] Referring first to FIG. 1, there is shown a preferred
embodiment of endoluminal flow diverter 10 which in this particular
example is sized to fit within the basilar artery of a patient, as
described in further detail below.
[0034] The flow diverter 10 includes a distal support 12 which in
this embodiment is in the form of a resilient ring of generally
circular form. The distal support 12 is located at the distal
extremity of the flow diverter 10. A proximal support 14, again
being in this embodiment in the form of an annular ring of
resilient material, is located at the proximal end of the flow
diverter 10. It is preferred that the distal and proximal supports
12, 14, form the distal and proximal extremities, respectively, of
the flow diverter 10.
[0035] Supported by and extending between the proximal and distal
supports 12, 14 is a diverter element 16 which in this example is a
substantially rectangular panel made of impermeable or
substantially impermeable material and which twists in the
longitudinal direction of the flow diverter 10. More specifically,
the panel 16 is attached at diametrically opposite sides 20 of each
support 12, 14. The attachment may be by a solder joint, welding,
use of bonding agent or any other suitable attachment method. In
this embodiment, the panel 16 is attached to the supports 12, 14,
such that the proximal edge 22 of the panel 16 is aligned with the
proximal edge 24 of the distal support 12, while the distal edge 26
of the panel 16 is aligned with the distal edge 28 of the proximal
support 14. In other embodiments, the edges 22, 26 of the panel 16
may be attached at any location within the length, or depth, of the
support rings 12, 14.
[0036] The proximal and distal supports may be made of an
elastically deformable material or a spring material such as spring
steel. The supports are preferably made of a shape memory material,
preferably a shape memory alloy such as nickel titanium alloy
(Nitinol) or cobalt chromium. The panel 16 may be made of the same
material as the proximal and distal supports 12, 14 but may be made
of other materials. These materials and other materials preferably
used for the device 10 are anti-thrombotic material.
[0037] In the preferred embodiments the device is made of
radiopaque materials of or includes radiopaque markers. In the
preferred embodiment, radiopaque markers or material are provided
in the support rings 12, 14.
[0038] It will be appreciated that when made of a spring or shape
memory material, the device 10 will exhibit resilience, for example
compressibility in the radial direction, yet will exert a force
tending it to its rest shape, that is its shape when not subjected
to an external force. The device can thus be radially compressed in
an introducer assembly for delivery and will expand when released
for the introducer assembly constraints, in practice until it abuts
and presses against the vessel walls as described in detail below.
When made of a shape memory material, the device can be
manufactured to have a transition temperature around body
temperature and thus to exhibit its elastic return force only once
delivered into the patient's vessel. For delivery purposes, the
device can be twisted along its longitudinal axis, which will cause
twisting and radial compression of the device, specifically by
twisting of the diverter element 16 and the supports 12, 14 on
themselves. Once the device is freed to revert to its non-twisted
shape, that is the device is released from the introducer assembly
and hence from constraining elements holding it twisted, the
supports 12, 14 and the diverter element 16 will untwist to adopt
the configuration shown in FIG. 1.
[0039] The proximal and distal support rings 12, 14 may be
continuous rings of strip material or wire. In other embodiments it
may have other configurations, such as a split ring, or a
conventional stent ring having, for example, a sinusoidal or zigzag
shape for radial compressibility. Furthermore, each of the proximal
and distal support rings 12, 14 may be made of a single element but
could in other embodiments be a set of annular elements, such as
turns of a coil, of a strip or the like. FIG. 5 shows an embodiment
of device 10 in which the proximal 12' and distal 14' support
elements are in the form of split rings. This structure will
enhance the radial compressibility of the support elements and will
still enable them to expand radially outwardly on release from the
introducer assembly, thereby to provide support against the vessel
wall and support to the panel 16.
[0040] Referring now to FIG. 2, there is shown a side elevational
view of the flow diverter 10 of FIG. 1, from a view point
perpendicular to the proximal edge 22 of the panel 16. It can be
seen that the edge 22 of the flow diverter is disposed in the plane
of the sheet of the drawing, whereas the distal edge 26 of the
panel is at substantially 90.degree., being substantially
perpendicular to the plane of the sheet of the drawing. In other
words, the diverter element 16 is in this embodiment twisted by an
angle of about 90.degree. between its proximal and distal
extremities. FIG. 2 also shows an example of the preferred lengths
of the flow diverter 10 for deployment in the basilar artery. This
preferred length is in the range of about 10 mm to about 15 mm.
[0041] FIG. 3 is a view similar to FIG. 2 but in which the flow
diverter 10 has been rotated by 90.degree., in which case the
proximal edge 22 of the diverter element 16 is normal for the plane
of the paper of the drawing, whereas the distal edge 26 of the
diverter element 16 is parallel to the plane of the paper of the
drawing. FIG. 3 also shows an example of the dimensions of the
proximal and distal support elements 12, 14 for a flow diverter 10
for deployment in the basilar artery. In this embodiment, the
proximal and distal support elements 12, 14 preferably have a depth
or length in the range of about 1 mm to about 2 mm.
[0042] FIG. 4 is a bottom plane view of the flow diverter 10, in
which the twist of the panel 16 can be seen through the 90.degree.
of the preferred embodiment. FIG. 4 also shows the preferred
diameter of the flow diverter 10, again for a diverter sized to fit
within the basilar artery. In this embodiment, the diverter 10 has
a diameter in the range of about 2 mm to 5 mm.
[0043] The wall thickness of the support elements 12, 14 and of the
diverter element 16 is between about 0.5 mm to about 2.0 mm for a
flow diverter having the dimensions given in the described example.
It is to be understood that the diverter element 16 could have a
greater or lesser twist than 90.degree., although a twist of
90.degree. is preferred.
[0044] With reference to FIGS. 1 to 4, it will be appreciated that
the flow diverter 10 is sized such that the proximal and distal
supports 12, 14 fit within a patient's vessel so as to press
against the internal vessel walls to keep the flow diverter in
position. The side edges 30, 32 of the diverter element or panel 16
are preferably shaped and sized so as to extend to the lateral
periphery of the flow diverter 10 and in particular to or close to
the deployed diameter of the proximal and distal support elements
12, 14. In this regard, the thickness of the preferred support
elements 12, 14 will generally be immaterial with respect to the
contact of the side edges 30, 32 of the diverter element 16 with
the vessel walls.
[0045] With such dimensions, the diverter element 16 will extend
across the entire diameter of the vessel and will twist along the
length of the flow diverter 10, such that any blood passing into
the flow diverter 10 (through the patient's vessel) will be
subjected to the twisting flow diverter path produced by the
diverter element or panel 16. This is the preferred arrangement,
namely that the entirety of fluid flow through the device 10 and
through the vessel in which the device 10 is implanted is subjected
to the twisting action produced by the twisted divert element or
panel 16. It is not excluded, however, in some embodiments that
there may be a narrow gap between the side edges 30, 32 of the
diverter element 16 and the vessel walls, possible primarily
because of fluid stagnation or lamination at the vessel surfaces.
This latter option is, however, not generally preferred.
[0046] The provision of a diverter element 16 in the form of
uniform thickness along its length and which is fixed at
diametrically opposite locations on the support elements 12, 14
ensures that there is the same volume of fluid passing that the
inlet of the device than leaves the outlet of the device and also
either side of the panel. This ensures that there is no overall
change in pressure of fluid passing through the element 10, solely
a smoothing of that pressure across the cross-sectional area of the
device 10 and thus of the vessel.
[0047] Referring now to FIG. 6, there is shown another embodiment
of flow diverter 100 similar to the embodiment of FIGS. 1 to 5 but
in which the diverter panel 160 is formed with longitudinal slits
161 therein. The slits 161, which in some embodiments may provide
no gap in the surface of the panel 160, make it easier for the
panel 160 to twist on itself so as to compress the device 100 for
delivery purposes. The panel 160 still provides a surface for
guiding the flow of fluid through the device 100, effectively the
same as a whole panel 16 as in the previous embodiments. As will be
apparent in FIG. 6, the slits are in a plurality of series along
the length of the panel 160, with the slits in adjacent series
being laterally offset from one another. The skilled person will
appreciate that the device 100 can have any of other
characteristics and elements of the devices taught herein.
[0048] FIG. 7 shows another embodiment of device 110, in which the
proximal and distal support elements 112, 114 are stent rings of a
stent 130 which extends for the whole length of the device 110. The
stent 130 provides longitudinal support to the device 110 and to
the panel 16. A similar embodiment of device 210 is shown in FIG.
8, in which the panel 116 is similar to the panel of the embodiment
of FIG. 6. It will be apparent that in the embodiments of FIGS. 7
and 8, as with all the other embodiments taught herein, the
supports 112, 114 may be in the form of zigzag stents, as well as
taking any of the other forms taught herein.
[0049] Referring now to FIG. 9, there is shown by way of
illustration only a schematic diagram of a cross-section of a part
of a patient's cerebral vasculature and in particular of the
basilar artery 40 and its bifurcation into the right posterior
cerebral artery 42 and the left posterior cerebral artery 44. In a
healthy anatomy, the vessel wall opposite the bifurcation 46
exhibits an indentation 48 which assists in the guiding of blood
into the posterior cerebral arteries 42, 44. The arrows 50 in FIG.
5 depict the flow of blood from the basilar artery into the right
and left posterior cerebral arteries 42, 44. The size and relative
positions of the arrows 50 depict the speed and strength of the
flow at the various positions within the basilar artery 40.
Specifically, adjacent the walls 52 of the basilar artery 40, flow
is reduced, whereas towards the center of the basilar artery 40
flow is as its highest. In other words, the strength of the flow
and therefore flow pressure increases from the edges of the wall 52
of the basilar artery 40 towards the center point of the artery.
This is typical of laminar flow.
[0050] Referring now to FIG. 10, this shows the same vessels as
FIG. 9, that is the basilar artery 40 and right and left posterior
cerebral arteries 42, 44, but in a patient with a developed
aneurysm 60 at the point of bifurcation. This is typically caused
by a weakening of the vessel wall at the point of bifurcation, the
weakening creating an aneurysm sack as the result of continued
pressure of blood from the basilar artery 40 to the bifurcation.
The skilled person will appreciate that in a condition such as that
depicted in FIG. 10, the aneurysm 60 will be subjected to the
highest pressure/flow part of the blood from the basilar artery 40.
This pressure will tend to cause the aneurysm sack 60 to grow in
size, with consequential weakening of the vessel wall. Left
untreated, this can result in the rupture of the vessel wall and of
haemorrhaging.
[0051] FIG. 11 shows the vessel anatomy of FIG. 10, in which an
embolization coil has been fitted into the aneurysm sack 60 in
order to fill this. The purpose of the embolization coil 62 is to
close off the volume of the sack 60 to prevent further flow of
blood into the aneurysm sack and thereby to reduce the pressure on
the walls of the vessel within the sack 60. However, as depicted in
FIG. 11 there is continued flow of blood 50 towards the aneurysm
sack 60, with the part of greatest flow and pressure heading
directly towards the neck or opening 64 of the aneurysm 60. Thus,
the flow of blood 50 will continue to apply pressure into the
aneurysm.
[0052] Referring now to FIG. 12, this is a view similar to FIG. 11,
but in which the flow diverter 10 taught herein is deployed within
the basilar artery 40. The flow diverter 10 has the effect of
imparting a twist and slowing of the central portion of the flow 50
of blood in the artery 40, as shown in schematic form by the arrows
70. As a result, the flow diverter 10 causes a reduction in the
flow and pressure of blood at the center point of the artery 40 and
therefore towards the aneurysm 60, with a consequential reduction
in the force imparted to the vessel walls at the aneurysm 60. In
particular, the twist imparted to the flow 50 of blood will reduce
lamination within the flow of blood and thus even out of the
pressure across the diameter of vessel. Moreover, the twist or
rotation imparted to the flow of blood can also reduce the flow of
blood at the center of the vessel, in effect by the creation of a
vortex void. This can substantially reduce pressure at the aneurysm
60 and assist in the healing thereof.
[0053] FIG. 12 shows an embolization coil 62 disposed within the
aneurysm sac 60, although it is to be understood that this may not
be necessary in order to treat the aneurysm 60. The diverter
element or panel 16, 116 of the flow diverter preferably has an
even twist along its length, although in other embodiments the
diverter element 16 could have a varying twist, for instance an
increasing twist from its distal end 12 to its proximal end 14, in
the orientation shown in FIG. 12 and thus along the direction of
fluid flow.
[0054] The diverter element 16, 116 need not be made of a spring
material or shape memory material and in some embodiments could be
made of a relatively soft material, or biomaterial which is
absorbable or otherwise, supported in its twisted configuration by
the proximal and distal support elements. In such an embodiment,
the proximal and distal support elements could be coupled to one
another, for example by appropriate struts or tethers. Struts or
tethers of such a nature could be provided in all of the
embodiments disclosed herein.
[0055] In other embodiments, the proximal and distal support
elements could be connected together or a part of a singular
support element. Such a support element could be a sleeve extending
for the length of the flow diverter, in one example being in the
form of a stent as shown in FIGS. 7 and 8.
[0056] It is to be appreciated that the embodiments of flow
diverter taught herein may be provided with other features commonly
found with implantable medical devices, for example anchoring
elements in the form of barbs or the like, retrieval elements such
as hooks and the like for withdrawing device from a patient's
vessel after completion of a medical procedure. It is envisaged
also that the device could be retained permanently within a
patient's vessel, not just to treat a formed aneurysm but also in
order to prevent the formation of aneurysms or further aneurysms
over time.
[0057] All optional and preferred features and modifications of the
described embodiments and dependent claims are usable in all
aspects of the disclosure taught herein. Furthermore, the
individual features of the dependent claims, as well as all
optional and preferred features and modifications of the described
embodiments are combinable and interchangeable with one another. It
will be understood that this invention is not limited to the
disclosed embodiments, as those having skill in the art may make
various modifications without departing from the scope of the
following claims.
* * * * *