U.S. patent application number 11/296590 was filed with the patent office on 2006-04-20 for body lumen closure.
This patent application is currently assigned to Boston Scientific Corporation. Invention is credited to Sally C. Thornton.
Application Number | 20060085066 11/296590 |
Document ID | / |
Family ID | 28673796 |
Filed Date | 2006-04-20 |
United States Patent
Application |
20060085066 |
Kind Code |
A1 |
Thornton; Sally C. |
April 20, 2006 |
Body lumen closure
Abstract
Method and apparatus implementing and using techniques for body
lumen closure, including use of an implantable medical closure
device. The device includes a flexible strand defining an arcuate
form. The strand is deformable upon implantation from a large
cross-section condition to a small cross-section condition and has
at least two anchoring portions disposed along the strand. The
anchoring portions are configured to penetrate a wall of a body
lumen such that when the strand is deformed to the small
cross-section condition, the wall of the body lumen is disposed
inwardly.
Inventors: |
Thornton; Sally C.;
(Marlborough, MA) |
Correspondence
Address: |
BROOKS & CAMERON, PLLC
1221 NICOLLET AVENUE
SUITE 500
MINNEAPOLIS
MN
55403
US
|
Assignee: |
Boston Scientific
Corporation
|
Family ID: |
28673796 |
Appl. No.: |
11/296590 |
Filed: |
December 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10115552 |
Apr 3, 2002 |
7007698 |
|
|
11296590 |
Dec 7, 2005 |
|
|
|
Current U.S.
Class: |
623/2.41 |
Current CPC
Class: |
A61B 17/068 20130101;
A61F 2220/0016 20130101; A61B 17/0644 20130101; A61F 2/2445
20130101; A61F 2/2475 20130101; A61B 2017/0649 20130101 |
Class at
Publication: |
623/002.41 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. An implantable medical closure device, comprising: a flexible
strand defining a continuous arcuate form having a first half with
a first anchoring end and a second half with a second anchoring
end, the first half and the second half being opposed relative a
center line bisecting the flexible strand, where in a first state
the flexible strand adjacent the first anchoring end and the second
anchoring end provide for a tangential line that is parallel with
the center line, and in a second state the flexible strand adjacent
the first anchoring end and the second anchoring end provide for
lines that are no longer parallel with the center line.
2. The device of claim 1, where the flexible strand is formed of a
material that can provide a force to move the first anchoring end
and the second anchoring end toward the first state.
3. The device of claim 2, where the material is a metal.
4. The device of claim 3, where the metal is nitinol.
5. The device of claim 1, where the strand is a filament-form.
6. The device of claim 1, where the first anchoring end and the
second anchoring end include a barb.
7. The device of claim 1, where the flexible strand is a flexible
polymer.
8. The device of claim 1, where the flexible strand defines at
least one loop for the continuous arcuate form.
9. An implantable medical closure device, comprising: a flexible
member having a first half and a second half that extend from a
center line in a continuous arcuate form, and having a first
anchoring end and a second anchoring end opposed to the first
anchoring end across the center line, where in a first state the
flexible strand adjacent the first anchoring end and the second
anchoring end provide for a tangential line that is parallel with
the center line, and in a second state the flexible strand adjacent
the first anchoring end and the second anchoring end provide for
lines that are no longer parallel with the center line.
10. The device of claim 9, where the flexible strand is formed of a
material that can provide a force to move the first anchoring end
and the second anchoring end toward the first state.
11. The device of claim 10, where the material is nitinol.
12. The device of claim 9, where the first anchoring end and the
second anchoring end include a barb.
13. The device of claim 9, where the flexible strand defines at
least one loop for the continuous arcuate form.
14. A catheter system, comprising: a catheter for delivery into a
lumen, the catheter including an expander that can be operated
between a small cross-section and a large cross-section; and a
closure device positioned about the expander, the closure device
comprising a flexible strand defining a continuous arcuate form
having a first half and a second half that extend from a center
line, the first half having a first anchoring end and the second
half having a second anchoring end, where when the closure device
is positioned on the expander in the small cross-section the
flexible strand adjacent the first anchoring end and the second
anchoring end provide for a tangential line that is parallel with
the center line, and when the closure device is positioned on the
expanded in the large cross-section, relative the small
cross-section, the flexible strand adjacent the first anchoring end
and the second anchoring end provide for lines that are no longer
parallel with the center line.
15. The catheter system of claim 14, where the expander comprises
an inflatable balloon.
16. The catheter system of claim 14, where the expander comprises a
mechanical expander.
17. The catheter system of claim 14, where the expander comprises a
leveraging device.
18. The catheter system of claim 17, where the leveraging device
comprises: a two-part axial member including a first outer part and
a second inner part; a splayed cuff connected to the distal end of
the first outer part of the two-part axial member; and at least two
flexible legs connected to the distal end of the second inner part
of the two-part axial member and flared outwardly to contact the
distal end of the splayed cuff.
19. The catheter system of claim 17, where the closure device is
positioned about the flexible legs; the second inner part of the
two-part axial member is moveable in a first direction such that
the flexible legs are pressed against the splayed cuff causing the
flexible legs and the splayed cuff to expand radially; and
expansion of the flexible legs expands the closure device from the
first small cross-section condition to the larger cross-section
condition.
20. The catheter system of claim 19, where the second inner part of
the two-part axial member is moveable in a second direction such
that the flexible legs move away from the splayed cuff causing the
flexible legs and the splayed cuff to retract.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/115,552, filed Apr. 3, 2002, the specification of which is
incorporated herein by reference.
BACKGROUND
[0002] A venous valve functions to prevent retrograde flow of blood
and allow only antegrade flow of blood to the heart. Referring to
FIG. 1A, a healthy venous valve 12 is illustrated in a vessel 10.
The valve is bicuspid, with opposed cusps 14. In the closed
condition, the cusps 14 are drawn together to prevent retrograde
flow (arrow 16) of blood. Referring to FIG. 1B, if the valve is
incompetent, the cusps 14 do not seal properly and retrograde flow
of blood occurs. Incompetence of a venous valve is thought to arise
from at least the following two medical conditions: varicose veins
and chronic venous insufficiency.
SUMMARY
[0003] In a first aspect, the invention features an implantable
medical closure device. The device includes a flexible strand
defining an arcuate form. The strand is deformable upon
implantation from a large cross-section condition to a small
cross-section condition and has at least two anchoring portions
disposed along the strand. The anchoring portions are configured to
penetrate a wall of a body lumen such that when the strand is
deformed to the small cross-section condition, the wall of the body
lumen is disposed inwardly.
[0004] The strand can also be deformable from a second small
cross-section condition to the large cross-section condition, for
example, the strand may be deformed to the second small
cross-section condition to facilitate delivery of the strand to a
treatment site, where it is then deformed to the large
cross-section condition upon implantation. The strand can include
free ends, which free ends can include the anchoring portions of
the strand. The strand can define an arc, a helix or can include
linear leg portions. The strand can be a filament-form or a band
and may be corrugated. The strand can deform from the large
cross-section condition to the small cross-section condition by,
for example, elastic recovery forces or thermal shape-memory
effect. The strand can be formed of metal, for example, nitinol.
The anchoring portions of the strand can include, for example, a
loop or a barb.
[0005] In another aspect, the invention features a catheter system,
which system includes a catheter for delivery into a lumen. The
catheter includes an expander that can be operated between a small
cross-section and a large cross-section. The catheter system also
includes a closure device positioned about the expander. The
closure device is a strand defining an arcuate form and including
at least two anchoring portions configured to penetrate a wall of a
body lumen. The closure device is deformable by the expander from a
first small cross-section condition to a larger cross-section
condition to dispose the closure device into engagement with the
lumen wall. The closure device is further deformable to a second
small cross-section condition, so that the wall of the body lumen
is disposed inwardly.
[0006] The expander can take any convenient form, including, for
example, an inflatable balloon, a mechanical expander or a
leveraging device. The mechanical expander can include a two-part
axial member having a first inner part connected to a first coiled
spring and a second outer part connected to a second coiled spring.
The closure device is mounted on the first and second coiled
springs, and the first inner part of the axial member is rotatable
to expand the first coiled spring and the second outer part of the
axial member is rotatable to expand the second coiled spring.
Expansion of the first and second coiled springs expands the
closure device. Each coiled spring can include a distal end
configured to fit within a groove formed on either end of the
closure device.
[0007] The leveraging device can include a two-part axial member
including a first outer part and a second inner part. A splayed
cuff is connected to the distal end of the first outer part of the
two-part axial member, and at least two flexible legs are connected
to the distal end of the second inner part of the two-part axial
member. The legs are flared outwardly to contact the distal end of
the splayed cuff. The second inner part of the two-part axial
member is moveable toward the splayed cuff such that the flexible
legs and the splayed cuff expand radially. The closure device is
positioned about the flexible legs and expansion of the flexible
legs expands the closure device from a first small cross-section
condition to a larger cross-section condition. The second inner
part of the two-part axial member is also moveable away from the
splayed cuff such that the flexible legs and the splayed cuff
retract.
[0008] In another aspect, the invention features a method of
treating a body lumen. The method includes delivering a closure
device into a lumen and positioning the strand about the lumen such
that a portion of the strand penetrates the wall of the lumen. The
method further includes deforming the strand to a smaller
cross-section condition such that the wall of the lumen is disposed
inwardly. The strand can be positioned about the lumen such that an
end of the strand extends through the wall of the lumen. The strand
can be disposed on a catheter, which catheter is then delivered
into the lumen. The catheter can include an expansion member.
[0009] Embodiments may have one or more of the following
advantages. Closure of a body lumen can be achieved in a minimally
invasive manner by delivery of a closure device to a treatment site
using a catheter. The closure device may be partially installed
within the lumen but configured to minimize profile and thus reduce
impedance to the flow of body fluids through the lumen. The amount
of lumen closure can be controlled by selecting the size and/or
recovery force of the closure device.
[0010] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0011] FIG. 1A is a cross-sectional schematic of a vessel including
a competent venous valve, while FIG. 1B is a schematic of a vessel
including an incompetent venous valve.
[0012] FIG. 2A is a longitudinal cross section of a vessel
including a closure device, while FIG. 2B is a radial cross section
of the vessel including the closure device.
[0013] FIGS. 3A and 3B are longitudinal and radial cross-sectional
views, respectively, illustrating delivery of a closure device
using a catheter.
[0014] FIGS. 4A, 4B and 4C are radial cross-sectional views
illustrating implantation of a closure device from within a
vessel.
[0015] FIG. 5 is a schematic view of an embodiment of a closure
device.
[0016] FIG. 6 is a schematic view of an embodiment of a closure
device.
[0017] FIG. 7 is a schematic view of an embodiment of a closure
device.
[0018] FIGS. 8A, 8B and 8C are radial cross-sectional views
illustrating implantation of a closure device from within a
vessel.
[0019] FIG. 9 is a schematic view of an embodiment of a closure
device.
[0020] FIG. 10 is a schematic view of an embodiment of a closure
device.
[0021] FIG. 11 is a schematic view of an embodiment of a closure
device.
[0022] FIGS. 12A, 12B, and 12D are longitudinal cross-sectional
schematic views and FIG. 12C is a radial cross-sectional schematic
view illustrating implantation of a closure device from within a
vessel.
[0023] FIGS. 13A, 13B, 13C, 13D and 13E are longitudinal
cross-sectional schematic views illustrating implantation of a
closure device from within a vessel.
[0024] FIGS. 14A, 14B and 14C are longitudinal cross-sectional
schematic views illustrating implantation of a closure device from
within a vessel.
[0025] FIGS. 15A, 15B and 15C are schematic views of an embodiment
of a medical device.
[0026] FIGS. 16A, 16B and 16C are longitudinal cross-sectional
schematic views illustrating implantation of a closure device from
within a vessel.
[0027] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0028] Referring to FIGS. 2A and 2B, a valve closure device 20 is
illustrated in position about a vessel 22 at the location of a
valve 24 including cusps 26. The closure device 20 is an arcuate,
open-ended, filament-form defining an arc that includes a body 28
which is located in the lumen of the vessel and two anchoring
portions 30 which extend into the walls 32 of the vessel. The
device 20 provides a force (arrows 34) that draws the vessel walls
inward, enhancing the function of the valve 24. As evident, the
closure device 20 does not substantially impede the flow of blood
through the vessel. The body portion 30 is thin and conforms
closely to the vessel wall, outside of central portions of the
vessel, where flow volume and rate is greatest.
[0029] Referring to FIGS. 3A and 3B, the closure device 20 can be
positioned at a treatment site in vessel 22 using a catheter 36,
which may be delivered into the vessel percutaneously. The catheter
36 includes a long, flexible body adapted for delivery through the
vessel and has near its distal end an expander 38, such as an
inflatable balloon. Suitable balloon catheters include angioplasty
balloon catheters and balloon catheters adapted for delivering
stents. An example utilizing a coextruded balloon is described in
Hamilton et al., U.S. Pat. No. 5,797,877, the entire contents of
which is incorporated herein by reference. The catheter may be
delivered over a guidewire (not shown). The device 20 may be
friction fit over the catheter. A retractable sheath may be used to
cover the device and balloon during delivery.
[0030] The closure device 20, in a radially compacted form, is
positioned over the expander 38 in a deflated condition for
delivery to the treatment site. Referring as well to FIGS. 4A-4C,
the closure device 20 is installed at the treatment site by
expanding the expander 38, i.e. by inflating the balloon. (In FIGS.
4A-4C, the expander and valve cusps are omitted to more clearly
illustrate the installation of the closure device 32). Referring
particularly to FIG. 4A, the closure device 20 is in a compacted
condition as it is carried to the treatment site on the catheter,
with the expander in the unexpanded condition. The closure device
20 is sized such that it is smaller than the cross-section of the
vessel. In the embodiment illustrated, the closure device 20
defines an arc that is generally concentric with the arc defined by
the vessel wall. In this condition, the anchoring portions 30
terminate in ends 21 which are oriented along a line 40,
substantially parallel to the center line 44 through the
cross-section of the vessel and generally parallel to a tangent 42,
on the blood vessel wall 32. Referring particularly to FIG. 4B, as
the closure device 20 is expanded, the device can both stretch
axially (arrow 45) and deform radially (arrow 46) as well as be
displaced upwardly (arrow 47). The axial stretching does not fully
accommodate the expansion. As a result, the ends of the filament
are deflected such that they are oriented along line 40, and come
into contact with the vessel wall 32, such that the ends become
embedded in the wall. The initial penetration of the ends can be
enhanced by rotating the catheter slightly about the catheter axis.
Referring to FIG. 4C, as the expander is contracted (i.e. deflated)
device 30 begins to contract. The ends 21 further penetrate the
wall 32. As shown the ends may pierce the entire thickness of the
wall, and deflect inwardly (arrow 49) to contract the vessel. The
closure device can be deployed near the base of cusps of an
incompetent venous valve, where the cusps meet the wall of the
blood vessel. The deployment may be upstream of the cusps.
Alternatively, the deployment site can be downstream of the cusps.
The catheter is withdrawn through the blood vessel in the same
manner the catheter was initially inserted.
[0031] The closure device may be made of a thin elongate, filament
form, such as a metal wire. The metal may be selected such that the
device is elastically expandable from the compacted condition for
delivery into a lumen to an expanded condition for implantation.
Once implanted, elastic recovery of the wire contracts the device
and the vessel wall. Suitable metals include elastic steels and
superelastic alloy materials such as nitinol. The filament may also
be a composite material, such as a composite wire. Superelastic
metals and composite wires are described in Heath, U.S. Pat. No.
5,725,570, and Mayer, U.S. Pat. No. 5,800,511, the entire contents
of both of which are incorporated herein by reference. The metal
may also be a temperature-effect shape memory superelastic alloy
that conforms to an implanted condition upon exposure to a
controlled temperature, e.g. body temperature. Suitable shape
memory alloys such as nitinol are discussed in Schetsky MacDonald
"Shape Memory Alloys," Encyclopedia of Chemical Technology
(3.sup.rd ed) John Wiley and Sons, 1982, vol. 20, p. 726-736. The
temperature of the device may be controlled, for example, by
heating the expander or by heating the balloon inflation fluid. The
wire may also be selected such that the device is plastically
deformed from the compacted condition to an expanded condition for
embedding the anchoring elements into the vessel wall, with some
elastic recovery after the expansion to contract the wall.
Alternatively, a mechanical gripper can be used to draw the
anchoring portions inward. The filament may also be made of a
flexible polymer. The device may be coated with a lubricious
polymer or a drug. For example, the anchoring portions may include
a tissue sealant to minimize bleeding and enhance vessel wall
integrity in the penetration regions.
[0032] The anchoring portions can also take a number of different
forms that permit the ends of the closure device to penetrate the
wall of the blood vessel, and restrain the ends from re-entering
the vessel. In the embodiment illustrated above, the device 20 is
formed of an open-ended strand in the shape of an arc. This shape
facilitates deflection of the ends of the strand so that they can
be embedded in the vessel wall and also provides a small profile
within the vessel, so that blood flow is not substantially impeded.
As illustrated above, the body of the device, within the vessel,
closely conforms to the inner wall of the lumen.
[0033] Referring to FIG. 5, in another embodiment, the closure
device 61 can be an open strand defining an arc, which includes
ends 64 with anchoring elements 62, which define loops. Once the
anchoring elements 62 are positioned on the exterior of the blood
vessel, the loops defined by the elements 62 prevent the ends 64 of
the closure device 61 from reentering the blood vessel and secure
the closure device 61 to the wall. The loops can be pressed into
the vessel wall on implantation. Alternatively, the ends can be
formed of a temperature effect shape memory metal, such that the
ends are in a substantially straight condition for implantation but
subsequently revert to a loop shape after being embedded in the
vessel wall.
[0034] Referring to FIG. 6, the closure device 66 can alternatively
include ends 68 with anchoring elements 69 configured with barbs,
such that the ends 68 can penetrate the wall of the blood vessel
and be prevented from reentering the blood vessel by the barbs of
the fish hook-like anchoring elements 69.
[0035] Referring to FIG. 7, the closure device can be an open
strand 120 having flared ends 122 that terminate in barb elements
123. The ends 122 can penetrate the wall of the blood vessel and
secure the strand 120 to the wall by the curvature of the flared
ends 122. The barb elements are easily pushed into the vessel wall
as the device is extended, but resist withdrawal from the wall as
the device deflects inwardly.
[0036] As shown in FIGS. 8A-8C, the closure device 70 can be a
spiraled open strand to form a loop and a half or more, so that the
ends 72 are positioned opposite one another, and include fish
hook-like anchoring elements 71. Referring particularly to FIG. 8A,
the closure device 70 is shown in a compacted condition, with the
anchoring elements 71 oriented along a tangent line 73, which is
substantially parallel to the center line 75 through the
cross-section of the blood vessel, and parallel to a tangent 74, on
the blood vessel wall. Referring particularly to FIG. 8B, as the
closure device 70 is expanded by the expansion device (not shown),
the strand can both stretch axially (arrow 78) and deform radially
(arrow 79). The axial stretch does not fully accommodate the
expansion. As a result, the free ends 72 of the strand are
deflected such that the tangent line 73 defines an angle .theta.
with respect to the tangent 74 on the vessel wall and thus
penetrates the vessel wall. Referring to FIG. 8C, as the device 70
begins to contract, the ends 72 of the strand further penetrate the
wall and deflect inwardly to contract the wall.
[0037] Referring to FIG. 9, the closure device 76 can be a spiraled
open strand to form a loop and a half, so that the ends 72 are
positioned opposite one another, and include anchoring elements 77
defining loops. Implantation of this device would be similar to
implantation of the device shown in FIG. 8, as described above.
[0038] Referring to FIG. 10, the closure device 80 can be a strand
in the shape of a thin, flat slotted band including three (or more)
anchoring elements 60. The slotted band 80 can include an upper
band 65, middle band 63 and lower band 67, where the upper band 65
and lower band 67 each include an anchoring element 60 on their
distal ends on an opposite side of the band 80 from an anchoring
element 60 formed at the distal end of the middle band 63.
Expansion of the closure device 80 by an expansion device causes
the anchoring elements 60 to penetrate the vessel wall. Upon
contracting the expansion device, the band 80 attempts to contract
to the smaller condition and, because the band 80 is secured to the
vessel wall, contracts the cross-section of the vessel.
[0039] Referring to FIG. 11, in another embodiment, the closure
device can be a closed, corrugated band 82. The band 82 includes
anchoring elements 83 projecting from the exterior surface of the
band. As the band 82 is expanded, the anchoring elements 83
penetrate the wall of the blood vessel. The anchoring elements 83
can be configured such that they lie flat while being transported
through the vessel, and are caused to protrude from the band 82 by
the expansion of the band 82 using an expansion device. When the
expansion device is contracted, the band 82 attempts to contract to
a smaller condition, and the anchoring elements 83 cause the
cross-section of the vessel to contract.
[0040] Referring to FIGS. 12A-12D, the closure device can be a
helical winding 85 having two or more anchoring portions 86 and
having any number of helical turns, for example three turns as
shown. Referring to FIG. 12A, the helical winding 85 can be
transported to the treatment site within a vessel 31 using a
catheter 88 having an expander 87 on the distal end. The treatment
site is in close proximity to an incompetent venous valve 24. The
helical winding 85 is mounted to the exterior of the expander 87
and can be held in place by any convenient manner, including, for
example, a friction fit. Optionally, a protective sheath 89 can
cover the expander 87 and helical winding 85 during transport and
be removed once the treatment site is reached. Referring to FIG.
12B, the expander 87 is expanded and thereby expands the helical
winding 85 from a small condition to a larger condition. The
expander 87 is expanded until the anchoring portions 86 of the
helical winding 85 penetrate the wall 44 of the vessel 31 and
secure the helical winding 85 to the interior of the vessel 31. The
helical winding 85 can have three anchoring portions 86 as shown in
FIG. 12C, or more or less anchoring portions. The expander 87 is
then contracted and the catheter 88 removed from the vessel 31, for
example, in the same manner the catheter 88 was deployed. Referring
to FIG. 12D, with the expander 87 no longer exerting pressure on
the helical winding 85, the helical winding 85 tends to contract to
the small condition, for example, due to elastic restoring forces
or temperature-effect shape memory effect, thereby pulling the
sides of the wall 44 inwardly and contracting the cross-sectional
area of the vessel 31. With the helical winding 85 in place within
the vessel 31, the cusps 38 of the valve 24 are pulled together so
that the valve 24 can function competently to prevent antegrade
flow within the vessel 31.
[0041] Referring to FIGS. 13A-13E, the closure device can be a
helical winding 94 that is positioned about the exterior of a
vessel 31 in the vicinity of an incompetent venous valve 24.
Referring to FIG. 13A, a catheter 90 having an expander 93 on the
distal end is transported to a treatment site with the expander 93
in a contracted state. The treatment site is at or near the
incompetent venous valve 24. The catheter 90 includes a lumen 91
having an opening 92 at or near the base of the expander 93.
Referring to FIG. 13B, at the treatment site the expander 93 is
expanded to at least the interior dimension of the vessel 31. The
helical winding 94 is formed of a shape-memory material and is
passed through the catheter lumen 91 in a substantially straight
position, as shown in FIG. 13C. The helical winding 94 is pushed
through the opening 92, which opening 92 is configured such that
the winding 94 is directed toward the wall 44 of the vessel 31. The
winding 94 penetrates and is pushed through the wall 44. The
shape-memory effect causes the winding 94 to revert to a helix as
the winding is pushed from the catheter lumen 91, and rides along
the outside of the vessel 31. Once the helical winding 94 has
completely exited the catheter lumen 91 and is situated about the
exterior of the vessel 31, the expander 93 is contracted and the
catheter 90 is withdrawn from the vessel. The helical winding 94 is
configured so that when the shape-memory effect causes the winding
to revert to a helix, the helical winding 94 pulls the wall 44 of
the vessel 31 inwardly, causing the cusps 38 to pull together so
that the valve can function competently. The winding 94 can be held
in place by friction.
[0042] Referring to FIGS. 14A-14C, the closure device 100 can be an
angular hinge-form with at least two linear legs 102. The closure
device 100 can be transported in a compressed condition to a
deployment site in the blood vessel by a delivery catheter 103
having a housing 105 for containing the closure device 100 in the
compressed condition until the deployment site is reached. The
device 100 can be pushed out of the housing 105 by the distal end
of the catheter, which can be temporarily connected to the device
100, for example, by a threaded connection. Referring particularly
to FIG. 14B, the device 100 will naturally expand upon being
released from the confines of the housing 105. An expansion device
106, such as an inflatable balloon, on the distal end of the
catheter 103 can be inflated to further expand the closure device
100 by spreading the legs 102 until the anchoring elements 104
penetrate the wall 44 of the blood vessel 41. The device 100 is
then pulled in the direction of the catheter by the distal end of
the catheter, which is still connected to the device 100. This
movement causes the anchoring elements 104 to fully penetrate the
wall of the blood vessel, and secure the device 100 to the vessel.
The catheter is disconnected from the device 100 and removed from
the vessel. The device 100 attempts to contract to a smaller
condition, thus causing the cross section of the blood vessel to
contract.
[0043] Referring to FIGS. 15A-15C, the expander can be a mechanical
expander 135 including at least two coiled springs 128, 129 and
having a two-part axial member including an outer tube 133 and an
inner rod 134. The inner rod 134 is affixed to a first coil 129 and
can rotate independently of the outer tube 133, which is affixed to
a second coil 128. The mechanical expander 135 is used in
conjunction with a closure device 125 configured to mount about the
coils 128, 129. Each coil 128, 129 has an end 130, 131 configured
to fit within a groove 127 formed on either end of the closure
device 125. In this manner, the coils 128, 129 and closure device
125 are held together while the expansion device is transported to
a treatment site. At the treatment site, the mechanical expander
135 is expanded to expand the closure device 125, thereby causing
the anchoring portions 126 of the closure device 125 to penetrate a
vessel wall, in a similar manner as described above.
[0044] The mechanical expander 135 expands by rotating the inner
rod 134 to expand the first coil 129 and rotating the outer tube
133 to expand the second coil 128. The coils 128, 129 expand
radially in opposite directions, exerting a radial force on the
closure device 125, causing the anchoring portions 126 to penetrate
a vessel wall. Once the closure device 125 is secured to the vessel
wall, the mechanical expander 135 can be disengaged from the
closure device 125 by sliding the mechanical expander 135 axially
away from the closure device 125. The mechanical expander 135 is
contracted by rotating the inner rod and outer tube in the opposite
directions used for expansion, and is withdrawn from the vessel.
Optionally, a retractable sheath can enclose the mechanical
expander 135 and closure device 125 while positioning the assembly
at the treatment site, which sheath is then retracted.
[0045] Referring to FIGS. 16A-16B, the expander can be a leveraging
device 112 having at least two flexible legs 114, an axial member
115 and a splayed cuff 116. A closure device 117 can be mounted
onto the exterior of the legs 114. At a deployment site, the axial
member 115 can be pulled causing the legs 114 to press against the
cuff 116. The force of the flexible legs 114 against the splayed
cuff 116 causes the flexible legs 114 to expand outwardly and the
splayed cuff 116 to fan out. The expansion of the circumference
around the flexible legs 114 causes the closure device 117 to
expand and anchor to the wall of the blood vessel 31, as described
above. Once the closure device 117 is secured to the wall, the
axial member 115 is pushed to release the pressure on the flexible
legs 114, causing them to revert back to the original compressed
condition. Similarly, with the force on the splayed cuff 116
removed, the cuff 116 recovers to the original state. The expansion
device can then be retracted from the vessel.
[0046] Other embodiments are within the scope of the following
claims. For example, a closure device may be used to treat vascular
vessels at locations without a valve to constrict the vessel at a
desired location and other body lumens outside the vascular
system.
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