U.S. patent application number 11/222069 was filed with the patent office on 2006-04-20 for methods and apparatus for treatment of hollow anatomical structures.
Invention is credited to Mark P. Parker, Fiona M. Sander, Russell B. Thompson, Arthur W. Zikorus.
Application Number | 20060085054 11/222069 |
Document ID | / |
Family ID | 35615566 |
Filed Date | 2006-04-20 |
United States Patent
Application |
20060085054 |
Kind Code |
A1 |
Zikorus; Arthur W. ; et
al. |
April 20, 2006 |
Methods and apparatus for treatment of hollow anatomical
structures
Abstract
One embodiment comprises an apparatus for applying energy to a
hollow anatomical structure having an inner wall. The apparatus
comprises an elongate shaft having a distal end and a proximal end
opposite the distal end; and a capacitive treatment element located
near the distal end. The capacitive treatment element is sized for
insertion into the hollow anatomical structure and placement near
the inner wall. The capacitive treatment element is configured to
create an electric field that extends at least partially into the
inner wall. Other devices and methods for treatment of hollow
anatomical structures are disclosed as well.
Inventors: |
Zikorus; Arthur W.; (San
Jose, CA) ; Thompson; Russell B.; (Los Altos, CA)
; Sander; Fiona M.; (Los Altos Hills, CA) ;
Parker; Mark P.; (San Jose, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
35615566 |
Appl. No.: |
11/222069 |
Filed: |
September 8, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60608335 |
Sep 9, 2004 |
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60617621 |
Oct 8, 2004 |
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60618827 |
Oct 13, 2004 |
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60621251 |
Oct 22, 2004 |
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60624009 |
Nov 1, 2004 |
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60645964 |
Jan 21, 2005 |
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60659287 |
Mar 7, 2005 |
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60659287 |
Mar 7, 2005 |
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60664316 |
Mar 22, 2005 |
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Current U.S.
Class: |
607/96 ; 607/105;
607/113; 607/99 |
Current CPC
Class: |
A61B 2018/0022 20130101;
A61B 18/1492 20130101; A61B 2018/046 20130101; A61B 2018/00404
20130101; A61B 18/08 20130101 |
Class at
Publication: |
607/096 ;
607/099; 607/113; 607/105 |
International
Class: |
A61F 7/00 20060101
A61F007/00; A61F 7/12 20060101 A61F007/12 |
Claims
1. An apparatus for applying energy to a hollow anatomical
structure having an inner wall, said apparatus comprising: an
elongate shaft having a distal end and a proximal end opposite said
distal end; a capacitive treatment element located near said distal
end; said capacitive treatment element being sized for insertion
into said hollow anatomical structure and placement near said inner
wall; said capacitive treatment element being configured to create
an electric field that extends at least partially into said inner
wall.
2. The apparatus of claim 1, wherein said capacitive treatment
element comprises a pair of elongate parallel electrodes separated
by a non-conductive element.
3. The apparatus of claim 2, wherein said non-conductive element
comprises an air gap.
4. The apparatus of claim 2, wherein said non-conductive element
comprises a solid non-conductive material.
5. The apparatus of claim 1, wherein said capacitive treatment
element comprises two pairs of elongate parallel electrodes
separated by non-conductive elements.
6. The apparatus of claim 1, wherein said capacitive treatment
element comprises a plurality of electrode pairs, and said
apparatus further comprises a control unit which is configured to
sequentially energize selected subsets of said plurality of
electrode pairs.
7. The apparatus of claim 1, wherein said capacitive treatment
element comprises a plurality of electrodes arranged in a generally
helical fashion.
8. The apparatus of claim 1, wherein said capacitive treatment
element comprises a plurality of electrodes arranged radially about
a longitudinal axis of said shaft.
9. The apparatus of claim 1, wherein said capacitive treatment
element comprises a plurality of electrodes arranged
longitudinally.
10. The apparatus of claim 1, wherein said capacitive treatment
element comprises a plurality of electrodes, and said apparatus
further comprises an electrically insulative layer which covers
some or all of said electrodes when said electrodes are
energized.
11. The apparatus of claim 1, wherein said capacitive treatment
element is configured to dielectrically heat said hollow anatomical
structure.
12. An apparatus for applying energy to a hollow anatomical
structure having an inner wall, said apparatus comprising: an
elongate shaft suitable for insertion into said hollow anatomical
structure; and a dielectric heating element connected to said
shaft.
13. The apparatus of claim 12, further comprising a substantially
permanent electrically insulative layer covering said dielectric
heating element.
14. The apparatus of claim 12, wherein said dielectric heating
element is configured to create an electric field that extends at
least partially into said hollow anatomical structure.
15. The apparatus of claim 12, wherein said dielectric heating
element comprises a plurality of electrode pairs, and said
apparatus further comprises a control unit which is configured to
sequentially energize selected subsets of said plurality of
electrode pairs.
16. The apparatus of claim 12, wherein said dielectric heating
element comprises a plurality of electrodes arranged radially about
a longitudinal axis of said shaft.
17. The apparatus of claim 12, wherein said dielectric heating
element comprises a plurality of electrodes arranged
longitudinally.
18. The apparatus of claim 12, wherein said dielectric heating
element comprises at least one electrode arranged substantially
helically around said shaft.
19. A method of treating a hollow anatomical structure, said method
comprising: inserting a capacitive treatment element into said
hollow anatomical structure; positioning said capacitive treatment
element near an inner wall of said hollow anatomical structure;
with said capacitive treatment element, creating an electric field
that extends at least partially into said inner wall.
20. The method of claim 19, further comprising heating at least a
portion of said hollow anatomical structure with said capacitive
treatment element.
21. The method of claim 20, wherein heating comprises causing
movement of dipolar molecules in said hollow anatomical
structure.
22. The method of claim 19, wherein said capacitive treatment
element comprises a plurality of electrode pairs, and said method
further comprises sequentially energizing selected subsets of said
plurality of electrode pairs.
23. The method of claim 19, wherein said hollow anatomical
structure comprises a vein, and said method further comprises
reducing an inner dimension of said vein by operating said
capacitive treatment element.
24. The method of claim 23, wherein reducing an inner dimension of
said vein comprises: positioning said capacitive treatment element
in a first portion of said vein; energizing said capacitive
treatment element while it is in said first portion; reducing or
shutting off power delivery to said capacitive treatment element
after energizing said capacitive treatment element while it is in
said first portion; after reducing or shutting off power delivery
to said capacitive treatment element, moving said capacitive
treatment element to a second portion of said vein; and energizing
said capacitive treatment element while it is in said second
portion.
25. The method of claim 19, wherein said capacitive treatment
element comprises at least one electrode arranged substantially
helically around said elongate shaft.
Description
RELATED APPLICATIONS; PRIORITY
[0001] This application claims the benefit under 35 U.S.C. .sctn.
119(e) of each of the following U.S. Provisional Patent
Applications: No. 60/608,335, filed Sep. 9, 2004, titled CATHETER
WITH THERMAL ELEMENT FOR LIGATION OF HOLLOW ANATOMICAL STRUCTURES;
No. 60/617,621, filed Oct. 8, 2004, titled ELECTRODE ELEMENT
SYSTEMS; No. 60/618,827, filed Oct. 13, 2004, titled CATHETER WITH
THERMAL ELEMENT FOR LIGATION OF HOLLOW ANATOMICAL STRUCTURES; No.
60/621,251, filed Oct. 22, 2004, titled VEIN CONFORMING CATHETER;
No. 60/624,009, filed Nov. 1, 2004, titled CATHETER WITH THERMAL
ELEMENT FOR LIGATION OF HOLLOW ANATOMICAL STRUCTURES; No.
60/645,964, filed Jan. 21, 2005, titled HOLLOW ANATOMIC STRUCTURE
CONFORMING CATHETER; No. 60/659,287, filed Mar. 7, 2005, titled
CATHETER WITH THERMAL ELEMENT FOR LIGATION OF HOLLOW ANATOMICAL
STRUCTURES; and No. 60/664,316, filed Mar. 22, 2005, titled
CATHETER WITH CAPACITIVE ELEMENT FOR TREATMENT OF HOLLOW ANATOMICAL
STRUCTURES. The entirety of each of the above-mentioned provisional
patent applications is hereby incorporated by reference herein and
made a part of this specification.
BACKGROUND OF THE INVENTIONS
[0002] 1. Field of the Inventions
[0003] Certain embodiments disclosed herein relate to methods and
devices for treating hollow anatomical structures such as varicose
veins.
[0004] 2. Description of the Related Art
[0005] The human venous system of the lower extremities consists
essentially of the superficial venous system and the deep venous
system with perforating veins connecting the two systems. The
superficial system includes the long or great saphenous vein and
the small saphenous vein. The deep venous system includes the
anterior and posterior tibial veins which unite to form the
popliteal vein, which in turn becomes the femoral vein when joined
by the short saphenous vein.
[0006] The venous system contains numerous one-way valves for
directing blood flow back to the heart. Venous valves are usually
bicuspid valves, with each cusp forming a sack or reservoir for
blood. Retrograde blood flow forces the free surfaces of the cusps
together to prevent continued retrograde flow of the blood and
allows only antegrade blood flow to the heart. When an incompetent
valve is in the flow path, the valve is unable to close because the
cusps do not form a proper seal and retrograde flow of the blood
cannot be stopped. When a venous valve fails, increased strain and
pressure occur within the lower venous sections and overlying
tissues, sometimes leading to additional, distal valvular failure.
Two venous conditions or symptoms which often result from valve
failure are varicose veins and more symptomatic chronic venous
insufficiency.
SUMMARY OF THE INVENTIONS
[0007] One embodiment comprises an apparatus for applying energy to
a hollow anatomical structure having an inner wall. The apparatus
comprises an elongate shaft having a distal end and a proximal end
opposite the distal end; and a capacitive treatment element located
near the distal end. The capacitive treatment element is sized for
insertion into the hollow anatomical structure and placement near
the inner wall. The capacitive treatment element is configured to
create an electric field that extends at least partially into the
inner wall.
[0008] One embodiment comprises an apparatus for applying energy to
a hollow anatomical structure having an inner wall. The apparatus
comprises an elongate shaft suitable for insertion into the hollow
anatomical structure; and a dielectric heating element connected to
the shaft.
[0009] One embodiment comprises a method of treating a hollow
anatomical structure. The method comprises inserting a capacitive
treatment element into the hollow anatomical structure; positioning
the capacitive treatment element near an inner wall of the hollow
anatomical structure; and, with the capacitive treatment element,
creating an electric field that extends at least partially into the
inner wall.
[0010] One embodiment is an apparatus for applying energy to a
hollow anatomical structure having an inner wall. In one such
embodiment, the apparatus comprises a heat emitter containing an
electrically resistive fluid. The heat emitter generates heat in
the resistive fluid by passing an electrical current through the
fluid. The heat emitter can be positioned within a hollow
anatomical structure in order to ligate a portion of the hollow
anatomical structure.
[0011] An alternative embodiment of an apparatus for applying
energy to a hollow anatomical structure having an inner wall
comprises a heat emitter containing a heating medium that has a
self-regulating maximum temperature associated with a phase change
of the heating medium. The heat emitter is generally configured to
be positioned within the hollow anatomical structure.
[0012] Another embodiment comprises a method of treating a hollow
anatomical structure having an inner wall. The method comprises
positioning a heating element in a first position in said hollow
anatomical structure. The heating element has a length and a width
measured orthogonal to the length. The length of the heating
element is preferably greater than the width. While in a first
position, the heating element is operated and emits heat from
substantially all of its length. The heat is emitted into the inner
wall of the hollow anatomical structure. The element is
subsequently moved to a second position within the anatomical
structure by a distance corresponding to approximately the
structure's length. While stationary in this position, the element
is again operated and again emits heat into the inner wall along
substantially the length of the element. In one embodiment, the
element is turned off before it is moved to the second
position.
[0013] In another embodiment is also an apparatus for applying
energy to a hollow anatomical structure comprises a catheter sized
for at least partial insertion into the hollow anatomical
structure. The catheter has a heat-emission region, which in turn
has a length and a width measured orthogonal to the length. The
length of the heat emission region is preferably greater than its
width. The heat-emission region emits heat at a substantially
uniform temperature along substantially all of its length.
[0014] In some embodiments, methods of adjusting an operating
temperature of the system are provided. In one embodiment, the
operating temperature can be adjusted by adjusting a relief valve.
In another embodiment, the operating temperature of the system can
be adjusted by choosing or adjusting the fluid used in the system.
In another embodiment, the operating temperature of the system can
be varied by adjusting both a relief valve and varying the
properties or amount of a fluid.
[0015] One embodiment is an apparatus for applying energy to a
hollow anatomical structure having an inner wall. In one such
embodiment, the apparatus comprises a heating element configured to
create an electric field that extends at least partially into a
tissue of a surrounding HAS in which the device is positioned. The
heating element generates heat in the surrounding fluid and/or
tissue by causing movement of dipolar molecules in the surrounding
fluid/tissue.
[0016] In one embodiment, a capacitive heating element comprises a
pair of elongate parallel electrodes separated by a non-conductive
element. The non-conductive element can comprise an air gap, a
solid non-conductive material, or a combination thereof. In another
embodiment, a capacitive heating element comprises two pairs of
elongate parallel electrodes separated by non-conductive elements.
In further embodiments, a capacitive heating element can include
three or more pairs of elongate parallel electrodes separated from
one another by electrically non-conductive elements. In further
embodiments, a capacitive heating element can include a plurality
of electrodes wrapped in a helical pattern around a solid or hollow
central core. In another embodiment, a capacitive heating element
comprises a plurality of ring-shaped electrodes. In each of the
above embodiments, the electrodes can be configured to be joined to
a power source in order to apply electric fields across adjacent
electrodes such that the electric fields extend outwards from the
radial extent of the device.
[0017] In one embodiment, a catheter comprises an elongate shaft
and an electrode element located distal of the elongate shaft. A
sheath is slidably disposed on the shaft. The sheath and catheter
are relatively moveable between a first configuration in which the
sheath covers substantially all of the electrode element, and a
second configuration in which the sheath covers less than
substantially all of the electrode element. The electrode element
may be energized by an energy source using alternating current in
the RF range.
[0018] In another embodiment, a catheter system comprises an
elongate shaft and an energy-emission element located distal of the
elongate shaft. The energy-emission element includes a plurality of
emission segments, a plurality of the segments are independently
operable to emit energy into the surroundings of the
energy-emission element. Optionally, the catheter system further
comprises a power source drivingly connected to the emission
segments. The power source is operable pursuant to a multiplexing
algorithm to deliver power to, and operate, the emission segments
in a multiplexed fashion. In one embodiment, the energy-emission
element comprises an electrode element. The electrode element may
be energized by an energy source using alternating current in the
RF range. In one embodiment, the electrode comprises an RF
emitter.
[0019] In another embodiment, a catheter system comprises an
elongate shaft and an energy-emission element located distal of the
elongate shaft. The energy-emission element has an effective axial
length along which the energy-emission element emits energy. The
effective axial length is adjustable.
[0020] In another embodiment, a catheter comprises an elongate
shaft and one or more expandable members located on the elongate
shaft. One or more electrode elements are positioned on the one or
more expandable members. The one or more electrode elements may be
energized by an energy source using alternating current in the RF
range.
[0021] In another embodiment, a device for treating a hollow
anatomical structure comprises an elongate structure with an
energy-delivering distal portion. The distal portion is movable
between a first position with a minimal transverse dimension and a
second position with a maximum transverse dimension, wherein the
maximum transverse dimension of the planar shape is selected to
engage an internal wall of the hollow anatomical structure
sufficiently to cause the hollow anatomical structure to conform to
the shape of the distal portion.
[0022] Certain disclosed embodiments comprise a device and/or a
method capable of providing heat energy along a circumferential
band to a vein wall over a specific length without localized
boiling, the likelihood of recurrence due to neovascularization,
excessive pain levels & recovery times, coagulum build-up
causing incomplete treatments, long treatment times from having to
pull back the catheter, and the issue of variable pullback rates
causing incomplete treatments and the subsequent need for
re-treatment.
[0023] In one embodiment, a catheter includes a plurality of
primary leads to deliver energy for ligating a hollow anatomical
structure. Each of the primary leads includes electrodes located at
the working end of the catheter. The primary leads are constructed
to expand outwardly within a single plane for the purpose of
conforming the hollow anatomical structure it is placed within to
the expanded profile of the catheter. In doing so, the hollow
anatomical structure is placed into apposition with the electrodes.
Energy can then be applied from the leads to create a heating
effect in the surrounding tissue of the anatomical structure. The
diameter of the hollow anatomical structure is reduced by the
heating effect, and the electrodes of the primary leads are moved
closer to one another as the diameter reduces. Where the hollow
anatomical structure is a vein, energy is applied until the
diameter of the vein is reduced to the point where the vein is
occluded. The catheter can include a lumen to accommodate a guide
wire or to allow fluid delivery.
[0024] Certain devices and methods disclosed herein are capable of
more evenly distributing energy along the target hollow anatomical
structure utilizing lower temperatures and the ability to regulate
power via a temperature feedback loop in a continuous simultaneous
length.
[0025] Devices and methods disclosed herein are preferably suitable
for ligation of hollow anatomical structures in the body, including
but not limited to varicose veins generally, perforator and
superficial veins, as well as hemorrhoids, esophageal varices, and
also fallopian tubes.
[0026] Certain objects and advantages of the invention are
described herein. Of course, it is to be understood that not
necessarily all such objects or advantages may be achieved in
accordance with any particular embodiment of the invention. Thus,
for example, those skilled in the art will recognize that the
invention may be embodied or carried out in a manner that achieves
or optimizes one advantage or group of advantages as taught herein
without necessarily achieving other objects or advantages as may be
taught or suggested herein.
[0027] All of the embodiments summarized above are intended to be
within the scope of the invention herein disclosed. However,
despite the foregoing discussion of certain embodiments, only the
appended claims (and not the present summary) are intended to
define the invention. The summarized embodiments, and other
embodiments of the present invention, will become readily apparent
to those skilled in the art from the following detailed description
of the preferred embodiments having reference to the attached
figures, the invention not being limited to any particular
embodiment(s) disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic view of one embodiment of a device for
ligating a hollow anatomical structure (HAS), including a handle
and connections;
[0029] FIG. 2 is a cut-away perspective view of a working (distal)
end of the device of FIG. 1;
[0030] FIG. 3 is a partial cross-sectional view of the working end
of the device of FIG. 1;
[0031] FIG. 4 is a schematic view of another embodiment of a HAS
ligating device, in which the working end is retracted within a
sheath;
[0032] FIG. 5 is a schematic view of the catheter of FIG. 4 in
which the working end of the catheter is expanded outside the
sheath;
[0033] FIG. 6 is a partial cut-away view depicting the working end
of the device of FIG. 1, within a HAS to be treated;
[0034] FIG. 7 is a partial cut-away view depicting the working end
of the device of FIGS. 4-5, expanded outside the sheath and within
a HAS to be treated;
[0035] FIG. 8 is a partial cut-away view depicting the working end
of the device of FIG. 1 within the treated HAS;
[0036] FIG. 9 is a cut-away view depicting the working end of the
device of FIGS. 4-5, expanded outside the sheath and within the
treated hollow anatomical structure;
[0037] FIG. 10 is a partial cut-away view of the working end of an
alternative embodiment of the device of FIG. 1;
[0038] FIG. 11 is a partial cutaway view of the working end of the
device of FIG. 10 in a short length;
[0039] FIG. 12 is a partial cutaway view of the working end of the
device of FIG. 10 in a long length;
[0040] FIG. 13 is a cut-away view of the working end of an
alternative embodiment of the device of FIG. 1;
[0041] FIG. 14 is a partial cut-away view of the working end of the
device of FIG. 13 in a short length;
[0042] FIG. 15 is a partial cut-away view of the working end of the
device of in FIG. 13 in a long length.
[0043] FIG. 16 is a cut-away view of the working end of another
embodiment of a HAS ligating device.
[0044] FIG. 17 is a cross-sectional end view of the ligating device
of FIG. 16.
[0045] FIG. 18 is a cut-away view of the working end of another
embodiment of a HAS ligating device.
[0046] FIG. 19 is a partial cut-away view of the working end of
another embodiment of a HAS ligating device.
[0047] FIG. 20 is a cross-sectional view taken through the diameter
of the working end of the embodiment of FIG. 19.
[0048] FIG. 21 is a cross-sectional view taken through the diameter
of the working end of another embodiment of a HAS treatment
device.
[0049] FIG. 22 is a cross-sectional view taken through the diameter
of the working end of another embodiment of a HAS treatment
device.
[0050] FIG. 23 illustrates another embodiment of an energy element
for use in a HAS ligating device.
[0051] FIG. 24 illustrate another embodiment of an energy element
for use in a HAS ligating device.
[0052] FIG. 25 illustrates a cross-sectional view taken through the
diameter of the working end of the embodiment of FIG. 24.
[0053] FIG. 26 is a schematic view of another embodiment of a
distal portion of a HAS ligating device having a balloon.
[0054] FIG. 27 is a photograph of a portion of an embodiment of a
HAS ligating device during manufacture.
[0055] FIG. 28 is a photograph of another portion of an embodiment
of a HAS ligating device during manufacture.
[0056] FIG. 29 is a photograph of an embodiment of a HAS ligating
device during manufacture.
[0057] FIG. 30 is a cross-sectional view of one embodiment of a
capacitive HAS heating element.
[0058] FIG. 31 is a schematic view illustrating an electric field
generated by the device of FIG. 30.
[0059] FIG. 32 is a cross-sectional view of another embodiment of a
capacitive HAS heating element.
[0060] FIG. 33 is a schematic view illustrating an electric field
generated by the device of FIG. 32.
[0061] FIG. 34 is a schematic perspective view of one embodiment of
a capacitive HAS heating element having a pair of helically-wound
electrodes.
[0062] FIG. 35 is a schematic view of an alternative embodiment of
a capacitive HAS heating device.
[0063] FIG. 36 illustrates an overall view of an RF element system
according to one embodiment;
[0064] FIG. 37 illustrates an exemplary embodiment of a catheter
sheath in a partially retracted position usable with the RF element
system of FIG. 36;
[0065] FIG. 38 illustrates a closer view of an exemplary embodiment
of a catheter usable with the RF element system of FIG. 36;
[0066] FIG. 39 illustrates a side view of another embodiment of the
working end of the catheter of FIG. 38;
[0067] FIG. 40 illustrates a side view of the device of FIG.
39;
[0068] FIG. 41 illustrates a table depicting an exemplary treatment
cycle usable with the catheter of FIG. 39;
[0069] FIG. 42 illustrates a side view of another embodiment of an
RF element system including an expandable balloon and a set of
fluid ports;
[0070] FIG. 43 illustrates an exemplary embodiment of an expandable
set of spline electrodes capable of conforming and contacting a
vein wall;
[0071] FIG. 44 illustrates an exemplary embodiment of an expandable
set of spline electrodes having a long expandable section with a
plurality of electrodes on each spline;
[0072] FIG. 45 illustrates an exemplary embodiment of an expandable
set of cantilevered spline electrodes capable of conforming and
contacting a vein wall;
[0073] FIG. 46 illustrates another embodiment of the working
portion of the catheter of FIG. 45 having a monopolar
arrangement;
[0074] FIG. 47 illustrates another embodiment of the working
portion of the catheter of FIG. 45 having a bipolar
arrangement;
[0075] FIG. 48 illustrates another embodiment of the working
portion of the catheter of FIG. 45 having a sheath capable of
heating a vein wall;
[0076] FIG. 49 illustrates another embodiment of a working portion
of the catheter body with individually expandable loops;
[0077] FIG. 50 illustrates the embodiment of FIG. 49 with the
individually expandable loops retracted;
[0078] FIG. 51 illustrates another embodiment of a working portion
of the catheter body formed from expandable foam;
[0079] FIG. 52 illustrates a cross-section of the device of FIG.
51;
[0080] FIG. 53 illustrates a perspective view of the device of FIG.
51;
[0081] FIG. 54 illustrates another perspective view of the device
of FIG. 51;
[0082] FIG. 55 illustrates another embodiment of an expandable
device having an expandable braid electrode;
[0083] FIG. 56 illustrates a close-up view of the expandable braid
electrode of FIG. 55;
[0084] FIG. 57 illustrates another embodiment of an expandable
device having an expandable braid electrode;
[0085] FIG. 58 illustrates the device of FIG. 57 in an expanded
configuration;
[0086] FIG. 59 illustrates another embodiment of an expandable
device having expandable ribbons along a working portion of the
catheter;
[0087] FIG. 60 illustrates the expandable device of FIG. 59 in an
expanded configuration;
[0088] FIG. 61 illustrates an embodiment of an expandable device
having a sheath and an expandable ribbon along a working portion of
the catheter in a non-expanded configuration;
[0089] FIG. 62 illustrates the embodiment of FIG. 61 in an expanded
configuration;
[0090] FIG. 63 illustrates another embodiment similar to the
embodiment shown in FIGS. 61 and 62 having another expanded
configuration;
[0091] FIG. 64 illustrates another embodiment similar to the
embodiment of FIGS. 61-63 having another expanded configuration;
and
[0092] FIG. 65 illustrates another embodiment of an expandable
device having an expandable balloon with a micro porous
surface.
[0093] FIG. 66 is schematic view of one embodiment of a device for
conforming a hollow anatomical structure (HAS) to a desired
shape.
[0094] FIG. 67 is a cross-sectional view of the device of FIG.
66.
[0095] FIG. 68 is a schematic view of an embodiment of an energy
source for use with a HAS conforming device.
[0096] FIG. 69 is a schematic view of an embodiment of a HAS
conforming device in which a distal end of the device is expanded
outside of a sheath.
[0097] FIG. 70 is an alternate view of the device of FIG. 69 in
which the working end of the catheter is withdrawn within the
sheath.
[0098] FIG. 71 is a cross-sectional detail view of an embodiment of
the sheath portion of FIG. 69.
[0099] FIG. 72 is a partial cross sectional view of an embodiment
of the distal portion of an HAS conforming device.
[0100] FIG. 73 is a cross-sectional view of another embodiment of a
HAS conforming device.
[0101] FIG. 74 is a schematic view of another embodiment of an HAS
conforming device in which the working end of the catheter is
expanded outside the sheath.
[0102] FIG. 75 is a cross-sectional view of the device of FIG. 74
in which the pull wire and catheter shaft is shown within the
sheath.
[0103] FIG. 76 is a schematic view of some additional embodiments
of a HAS conforming catheter.
[0104] FIGS. 77A-F illustrates embodiments of distal flexible
components for use in an HAS conforming device.
[0105] FIG. 78 is a schematic view of another embodiment of an HAS
conforming device in which the working end of the catheter is
expanded outside the sheath.
[0106] FIG. 79 is an alternate view of the embodiment of FIG. 78 in
which the working end of the catheter is withdrawn within the
sheath.
[0107] FIGS. 80-82 depict alternate embodiments of the device in
FIG. 79.
[0108] FIG. 81 is a view of an alternate embodiment of the device
in FIG. 79.
[0109] FIG. 82 is a view of an alternate embodiment of the device
in FIG. 79.
[0110] FIGS. 83-86 show schematic views of another embodiment in
the collapsed and expanded states of the device and respective
cross-sectional views of the same.
[0111] FIGS. 87-90 show schematic views of another embodiment of
the device in FIGS. 83-85 in the collapsed and expanded states of
the device and respective cross-sectional views of the same.
[0112] FIG. 91 is a view of a device within a vein in an
un-deployed state.
[0113] FIG. 92 is a view of a device within a vein in a deployed
state.
[0114] FIG. 93 is a view of a device in a deployed state within a
vein and the perivenous compartment.
[0115] FIG. 94 is a view of a device in a deployed state within a
vein and the perivenous compartment in which tumescent has been
applied.
[0116] FIG. 95 is a view of a device in a deployed state within a
vein and within the perivenous compartment in which tumescent and
manual compression have been applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0117] FIG. 1 shows an embodiment of a device or catheter 10 for
applying energy to a hollow anatomical structure (HAS), such as a
vein. The catheter 10 includes a catheter shaft 12 having a handle
14. The catheter shaft 12 can comprise a biocompatible material
having a low coefficient of friction. In one configuration, the
catheter shaft 12 is sized to fit within a vascular structure that
may be between 5 and 9 French, which corresponds to a diameter of
between about 1.7 mm (0.07 in) and about 3.0 mm (1.2 in), or other
sizes as appropriate to correlate to the HAS. Thus, in some
embodiments the catheter shaft 12 may have a diameter of about 1-2
mm. The handle 14 includes a fluid port 16 for infusion of an
electrically conductive fluid or liquid drawn from a reservoir 18,
a pressure relief valve 20 for venting the shaft 12 to ambient air,
and a connection 22 for interfacing with an energy source 24. In
the present embodiment, the energy source 24 can be either
alternating current (AC) or direct current (DC) like an RF
generator or other type of power supply. The fluid reservoir 18
provides a flow of electrically conductive fluid or liquid into the
catheter shaft 12, and the energy source 24 provides a power output
that the user can manually adjust. The system can also include a
temperature sensor (not shown) such as a thermocouple or thermistor
to provide feedback to the user regarding system operation and
temperature. For example, a thermocouple can be placed on the
surface of the shaft 12.
[0118] Referring now to FIGS. 2 and 3, a positive RF wire 26
encased in an insulation material 28, and a negative RF wire 30
encased in an insulation material 32, are located within a catheter
shaft 12. The insulation material 28, 32 is stripped or skived away
from a portion of the respective wires 26, 30 at specific intervals
along the lengths of the wires 26, 30 to expose the wires 26, 30 to
the interior of catheter shaft 12. The RF wires 26 and 30 are
skived along a length that corresponds to the desired
vein-treatment length. In the depicted embodiment, the skived areas
or electrodes are situated in a longitudinally-alternating
configuration along the lengths of the respective wires 26, 30.
However, in other embodiments a symmetric or mirrored configuration
may be employed, with the skived portions on the wires 26, 30
adjacent one another.
[0119] Contained within the catheter shaft 12 is a fluid lumen 34.
The fluid port 16 communicates with the interior of fluid lumen 34,
with the interior of catheter shaft 12 and with a manually
adjustable pressure relief valve 20. The fluid lumen 34 terminates
just proximal to the tip 36 and allows fluid to flow into the
interior of catheter shaft 12. The electrically conductive fluid or
liquid can flow from the reservoir 18, through the fluid port 16,
through the fluid lumen 34, into the catheter shaft 12, thus
surrounding the positive RF wire 26 and the negative RF wire 30.
The fluid lumen 34 can be used to infuse additional fluid into the
catheter shaft 12. This additional fluid may become necessary as a
replacement for fluid that has changed phase, formed vapor bubbles
and moved up the catheter shaft 12 toward the pressure relief valve
20. Replacement fluid can be slowly dripped into the catheter shaft
12 at a rate sufficient to keep the system functioning, but not so
much that the added fluid would cool the catheter shaft 12 too
much. In one embodiment, the fluid lumen 34 can have an outside
diameter of about 0.5 mm to 1 mm.
[0120] The catheter shaft 12 can be vented to ambient air via the
pressure relief valve 20. This valve can be used to build, maintain
and/or relieve pressure in the system and tune the boiling point as
desired. As the fluid is heated to its boiling point, the gaseous
bubbles that form within the shaft 12 interrupt the path of the
electrical energy as it flows through and heats the fluid. As the
fluid temperature increases, the presence of more and more bubbles
increases this inhibiting effect. Accordingly, the creation of
bubbles (and/or the retention of bubbles in the conduction path(s)
between the exposed portions of the wires 26, 30) is one mechanism
that can be used to control the temperature of the system. Bubbles
created through boiling can be controllably released through the
pressure relief valve 20, discussed above.
[0121] In addition, at a given pressure (which can be set via the
pressure relief valve 20) the conductive fluid has an inherent or
"self-regulating" maximum temperature or boiling point which in
turn sets an inherent or "self-regulating" maximum temperature of
the working end of the catheter. This advantageously provides an
effective safety feature for the catheter, which can be set to
prevent overheating of the treated tissue and/or to preclude the
need for a temperature feedback loop that actively governs power
delivery to achieve a desired set-point temperature.
[0122] In some embodiments, electrically conductive fluids of
varying degrees of viscosity, and conductivity might be employed.
Such fluids might include saline, water, biocompatible oils,
dextrose solution, and the like. The fluid is chosen to get a
desired boiling point. The boiling point can be derived from a
desired treatment temperature (for example, a treatment temperature
of 100.degree. might require a conductive-fluid boiling point of
113.degree., given potential losses in the catheter system, and
potential losses in the thermal coupling of the catheter to the
wall of the HAS in which the catheter is employed). Thus, a
temperature of the working end can be controlled by controlling the
boiling point of the fluid (for example, by choosing a fluid with a
particular boiling point), by controlling a flow rate of the fluid
through the system, or by controlling the pressure at which the
pressure valve vents.
[0123] The following table shows examples of liquids that can be
used alone or mixed in such a system, including the boiling points
of the liquids at one atmosphere (1 atm), or seven hundred and
sixty torr (760 mm Hg). TABLE-US-00001 Liquid Boiling Point
(.degree. C.) 0.9% Saline 100 Acetone 56.48 Benzene 80.1 Chloroform
62.26 Ethyl Acetate 77 Ethyl Alcohol 78.3 Heptane 98 Hexane 69
Hydrogen Peroxide 6% 106 Iron (III) Nitrate Xonahydrate 125
Isopropyl Alcohol 80.3 Liqui-Nox 101.1 Methanol 64.5 Naptha
(Benzine, 76C Naptha) 100-140 Octane 126 Petroleum Spirits 35-180
Sucrose Solutions (dextrose, fructose) 100-150
.alpha.-Trichloroethane 74.1 Trichloroethylene 86.7 Toluene 110.4
Water 100 Xylene (m, o, p) 139, 144.4, 138.3
[0124] The catheter shaft 12 can include an atraumatic tip 36 for
facilitating manipulation of the catheter into the HAS of the
patient. The tip 36 is preferably tapered inward or rounded at its
distal end, or the tip 36 can have other shapes that facilitate
threading or tracking of the catheter through the bends in the
vascular system.
[0125] In one embodiment, the tip 36 can, for example, be
fabricated from a polymer having a soft durometer, such as 70 Shore
A. Further, the tip can be fabricated from any number of materials
with varying durometer such as pebax, polyimide, polyethylene,
silicone (softer more atraumatic materials) or stainless-steel or
ceramic as a blunt tip. Additionally, the tip might employ an
endostructure or exostructure to define its flexibility
characteristics.
[0126] A second embodiment of the catheter, depicted in FIGS. 4 and
5, may be generally similar to the embodiment depicted in FIGS.
1-3, except as further described herein. The embodiment of FIGS.
4-5 employs a coiled catheter shaft 36 to facilitate apposition
with the HAS wall. The embodiment of FIGS. 4 and 5 may be
particularly useful in situations where external compression (such
as manual, Esmark, or Tumescent Anesthesia) of the HAS or other
methods are insufficient to cause the HAS diameter to reduce
sufficiently to appose a fixed-diameter catheter. The coiled
configuration may comprise an open helix or corkscrew, and can be
made from a deformable material like pebax, polyimide, polyethylene
or silicone. The helical shape can also be obtained by using a
shaped spine or wire made from nickel-titanium, stainless-steel or
other materials with similar characteristics.
[0127] An outer sheath 38 can be used to enclose and straighten the
coiled catheter shaft 36 for introduction into and advancement
through the HAS to be treated. In certain embodiments, the outer
sheath 38 can be retractable, and the treatment length can be
adjusted by actuating the retractable outer sheath 38 from outside
of the body. This can be done by introducing the catheter into the
body with the sheath 38 covering an active portion of the catheter
and advancing the tip to the treatment site. The sheath 38 can then
be withdrawn until the length of the active portion matches the
length of the desired treatment area. The retractable sheath 38 can
accordingly insulate adjacent tissue from thermal damage.
[0128] One embodiment of the inventions comprises a method of
treating a HAS by gaining HAS access; inserting a catheter with an
outer access sheath into the HAS; positioning the tip of the
catheter near the saphenofemoral junction or other desired
treatment starting point in the HAS; withdrawing the protective
outer sheath to allow the catheter to assume a deployed (e.g.
helical) shape (see the coiled catheter shaft 36 of FIG. 5);
supplying electrical energy to the device; maintaining the device
in position for a clinically effective time period (for example,
15, 30 or 60 seconds); retracting the catheter back into the outer
sheath; withdrawing the catheter from the HAS; and confirming that
the HAS has been occluded (using ultrasound, for example).
[0129] Referring now to FIGS. 6 and 8, the catheter shaft 12 of the
embodiment of FIGS. 1-3 is shown in the vessel segment to be
treated just prior to treatment and just after treatment,
respectively. Thus, in FIG. 6, the catheter shaft 12 extends inside
a HAS without touching the side walls of the HAS 42, but in FIG. 8,
the side walls 42 of the HAS are in apposition with the catheter
shaft 12.
[0130] Referring now to FIGS. 7 and 9, the catheter shaft 36 of the
embodiment of FIGS. 4-5 is shown in the vessel segment to be
treated just prior to treatment and just after treatment,
respectively. Thus, in FIG. 7, the catheter shaft 36 extends inside
a HAS without touching the side walls of the HAS 42, but in FIG. 9,
the side walls 42 of the HAS are in apposition with the catheter
shaft 36.
[0131] In some embodiments, a catheter can include holes positioned
along the length of the catheter tube to allow fluid to escape and
heat the surrounding tissue. Furthermore, in an embodiment where
such holes are present, higher fluid flow rates and pressure can be
maintained to force small jets of liquid against and/or into the
wall of the target anatomical structure.
[0132] FIG. 10 shows another embodiment of a HAS treatment device
configured to emit steam through a plurality of openings along a
portion of its length. Except as further described below, the
device of FIG. 10 can be generally similar to either of the
embodiments of FIGS. 1-3 or 4-5. The device may be constructed of a
catheter shaft 12 comprising a perforated outer sheath 80 at the
working end. The sheath 80 generally surrounds a fluid cavity 86
which can have an energy element 81 extending therethrough. In some
embodiments, the energy element 81 is configured to heat a liquid
contained within the fluid cavity 86.
[0133] In some embodiments, the sheath 80 is made of a material
that can withstand high temperatures, such as Polyamide, Teflon or
Ultem. This sheath 80 is preferably sufficiently lubricious to
allow introduction into the HAS, to facilitate navigation through
the HAS to the desired treatment site, and to prevent blood
coagulum build-up on its exterior. The sheath 80 can therefore be
coated with a lubricious and/or non-stick coating, comprising
Teflon or Paralyene, for example. The outer sheath 80 may also be
made from a suitable kink-resistant material, such as braided
Polyimide, for example.
[0134] As shown in FIG. 10, the sheath 80 can include a plurality
of micro-perforations 95. The micro-perforations 95 can be formed
by puncturing the sheath 80 substantially without removing
material. Thus, each micro-perforation provides a fluid pathway
between an interior and an exterior of the sheath 80 which is
substantially closed under normal conditions. However, when a fluid
pressure within the sheath exceeds a fluid pressure outside of the
sheath, the fluid will pass through the micro-perforations. The
internal/external pressure differential required to cause such a
fluid flow can generally be varied by varying properties of the
sheath, such as a durometer of the material, by varying the amount
of micro-perforations present on the sheath or by varying the
diameter of the micro-perforations themselves.
[0135] FIG. 10 also illustrates an energy element 81 located within
the sheath. The energy element 81 can comprise one or more RF
electrodes, thermal resistance heaters, laser, or other device
capable of delivering energy to a load. The energy element 81 may
comprise a resistive wire coiled around an inner member and
connected to the energy supply 24 via the connector 22 located at
the catheter handle 14. The resistive wire can be made of metal
capable of transferring electrical energy. For example, the wire
can be a material such as copper or nichrome. The energy element
can be powered by an AC or DC power supply. The energy element 81
may also comprise coaxially-placed electrodes as discussed above.
The energy element 81 is preferably configured to deliver a
controlled quantity of energy to a load surrounding or adjacent to
the element 81 at a controlled rate and/or for a controlled length
of time.
[0136] In some embodiments, the energy element 81 extends along
substantially the entire length of the outer sheath 80 so that the
inner member tip is adjacent the tip of the outer sheath 80. In
some embodiments, the energy element 81 may extend a finite length,
for example 45 cm, measured from the distal tip of the outer sheath
80 towards the proximal handle 14. Preferably, the length of the
energy element 81 generally corresponds to the desired length of
the HAS to be treated.
[0137] In some embodiments, energy is transferred from the energy
element 81 to a HAS via a fluid located within the outer sheath 80
and surrounding the energy element 81 within a fluid chamber 86. In
some embodiments, the fluid is introduced into the fluid chamber 86
as a liquid which is then heated above its boiling temperature,
thereby causing a phase change that initiates production of gas
(such as steam when the liquid is water). Once the fluid pressure
of the gas exceeds a threshold pressure, the gas is forced through
the micro-perforations in the outer sheath 80 towards the HAS.
Before the fluid pressure within the fluid chamber 86 exceeds the
threshold pressure, the micro-perforations remain closed, thereby
retaining the heated fluid within the fluid chamber 86.
[0138] The liquid may be delivered into the fluid chamber 86 via an
internal lumen 83 extending longitudinally through the energy
element 81. In some embodiments, the energy element 81 comprises
only a single distal opening such that fluid may exit through only
the very distal tip of the energy element 81. The energy element 81
further comprises a proximal opening (not shown) configured to
allow a fluid to enter the lumen in the handle 14 via a connector
20 from an auxiliary fluid source 18 (see FIG. 1). In some
embodiments, a fluid pressure applied by the fluid source 18 is
sufficient to ensure that the fluid chamber 86 remains filled, but
is not so high as to cause release of the liquid through the
micro-perforations 95.
[0139] In some embodiments, the fluid is heated through direct
contact with the energy element 81. The energy element 81 heats the
liquid via regulated power delivery from the energy source 24 (see
FIG. 1) until the liquid reaches its boiling point. The regulation
of delivered power can be accomplished with an electrical power
source via an optimized power curve created expressly for the
energy element 81.
[0140] The boundaries of the fluid chamber 86 are defined by the
outer sheath 80, the distal tip, and a proximally-placed seal
component 84 that seals around the energy element 81 and abuts the
inner walls of the outer shaft 80. The seal is preferably
substantial enough to prevent undesired leakage at the expected
operating fluid pressures. Thus, in some embodiments, the fit
between the seal component 84 and the energy element 81 is an
interference fit. Additionally, a material from which the seal
component 84 is made will preferably be substantially resistant to
high temperatures and will provide a good sealing force. In some
embodiments, the sealing component comprises a Silicone material.
Alternatively, the sealing component can be made of Pebax,
Santoprene, PET, or other suitable material. A seal component can
be formed by molding, casting, machining or otherwise shaping from
a suitable material.
[0141] In some embodiments, the length of the fluid chamber 86 can
be adjusted by varying an axial placement of the seal 84. For
example, in some embodiments this adjustment is performed by
actuating an attached seal actuation member 85. This actuation
member 85 is preferably strong enough and attached to the seal 84
with enough strength to allow for significant `pushability` as well
as `pullability` since it has to overcome a relatively large
frictional force created by the internal seal. Therefore, in some
embodiments, the actuation member 85 can be a tube made of a
material capable of providing significant column strength while
still bonding well to the seal, such as stainless-steel or Hytrel.
Actuation of the member 85 may be facilitated by any suitable
mechanism located at the proximal catheter handle 14.
[0142] With reference now to FIG. 11 and FIG. 12, in some
embodiments the entire length of the outer sheath 80 can include
micro-perforations 95. However, in the illustrated embodiment, the
seal position defines the proximal extent of the fluid chamber 86,
and hence the portion of the catheter configured to emit high
temperature gas is substantially limited to the section immediately
surrounding the fluid cavity 86. Thus, in the illustrated
embodiment, the length between the seal component 84 and the distal
tip of the sheath 80 corresponds to the treated length of the HAS.
In embodiments where the seal 84 is slidable relative to the outer
sheath 80, the treatment length can be adjusted from a minimum
length (for example: 15 cm) to a maximum length (for example: 45
cm) and any length in between. In some embodiments, the treatment
length can be adjustable between about 1 cm and about 60 cm. In
other embodiments, the treatment length can be adjustable between
about 5 cm and about 45 cm, and in one preferred embodiment, the
treatment length can be adjustable between about 15 cm and about 45
cm.
[0143] In the embodiment illustrated in FIG. 13, an energy element
91 may be substantially solid, such as a laser fiber, so that fluid
may not be delivered through it. In this embodiment, the seal 84
may still be statically or adjustably positioned so as to provide a
desired treatment length. The tip of the energy element 91 can be
axially positioned relative to the distal tip of the catheter and
seal 84 to provide optimized energy delivery. For example, in some
embodiments the distal tip of the energy element 91 is positioned
about half way between the seal 84 and the distal tip of the
catheter. Fluid may then be delivered through a separate fluid
lumen 92 that is placed within the outer sheath 80 and ends
adjacent a distal side of the seal 84. In some embodiments, a
structure forming the fluid lumen 92 may also act as a seal
actuation member (performing the function described above with
respect to the actuation member 85).
[0144] FIGS. 14 and 15 illustrate embodiments of a device with a
variable fluid chamber length and a solid energy element 91, such
as a laser fiber. In the embodiments of FIGS. 14 and 15, the seal
position defines the proximal extent of the fluid chamber 86, and
hence the portion of the catheter configured to emit high
temperature gas can be substantially limited to the section
immediately surrounding the fluid cavity 86. Thus, in the
illustrated embodiment, the length between the seal component 84
and the distal tip of the sheath 80 defines the treated length of
the HAS. In embodiments where the seal 84 slides relative to the
outer sheath 80, the treatment length can be adjusted from a
minimum length (for example: 15 cm) to a maximum length (for
example: 45 cm) and any length in between. In some embodiments, the
treatment length can be adjustable between about 1 cm and about 60
cm. In other embodiments, the treatment length can be adjustable
between about 5 cm and about 45 cm, and in one preferred
embodiment, the treatment length can be adjustable between about 15
cm and about 45 cm.
[0145] FIG. 16 shows the working end of another embodiment of a
device for ligating a HAS. In this embodiment, RF electrodes 101
are shown as a pair of linear, flat metal strips attached to an
outer surface and along the length (the length parallel to the axis
of cylindrical symmetry) of an inner catheter lumen 102. FIG. 16
shows only one of the two electrodes, as the second electrode is
located on the opposite side of the catheter lumen 102. FIG. 17
shows an end-on view of the structure of FIG. 16, showing the
electrodes 101 on either side of the catheter lumen 102. These
electrodes 101 can be flat wire, round wire or metal tape such as
copper tape or stainless-steel tape. Signal wires 103 may be
attached to one end of the electrodes 101 by soldering, spot
welding, bonding with a conductive adhesive, such as silver epoxy,
or by using other suitable methods.
[0146] In some embodiments, a thin electrically insulative material
104 such as polyimide, Teflon or silicone tape may be helically
wound around the inner lumen assembly (e.g., the inner lumen 102
and the electrodes 101). The insulative material 104 can be about
0.003 inches to about 0.020 inches thick. However, material
thicknesses outside of this range can also be used.
[0147] Helically winding an electrically insulative material 104
around the electrodes 101 can effectively form multiple discrete
shorter electrodes from each longer electrode 101. When the
sections of exposed electrodes are equal in surface area along each
strip (each exposed section having a corresponding exposed section
of approximately similar dimensions on the other electrode 101),
the heat produced starts near the signal wire attachment section
and eventually propagates along the electrodes 101 to the distal
end. For example, the portions of the electrodes 101 nearest the
attachment point of the signal wire 103 can be hotter than those
portions of the electrodes 101 farther away from that attachment
point. The pitch of the helical tape windings of the insulative
material 104 can be varied as shown in FIGS. 16 and 18, such that
the exposed electrode surface area decreases as the windings move
distally from the signal wire attachment point. Thus, in such an
embodiment, the heating is advantageously more uniform over the
length of the entire electrode strip pair. For instance, the pitch
of the wound insulative material 104 may vary so as to allow an
open gap width substantially less than the width of the material
itself at the distal end of the catheter, and substantially more
than the insulative material width towards the proximal end.
[0148] FIG. 18 shows an alternative embodiment of an energy
element. In the embodiment of FIG. 18, the electrode strips 101 are
helically wound around an inner catheter lumen 102 in a direction
counter to a helical winding direction of the insulative material
104. This counter winding of the electrodes 101 can prevent a
circumferential bias of the heat that can otherwise be generated by
the configuration of FIGS. 16 and 17, where the electrodes 101 are
not wound. Heat generated by purely longitudinal (non-wound)
electrodes 101 may have some zones of greater heat generation
nearer the portions of the catheter lumen 102 contacted by the
electrodes 101, thus creating a temperature gradient with a bias
between hotter and cooler zones. By winding the electrodes 101, the
temperature gradients can be changed and temperature bias can be
reduced.
[0149] FIGS. 19 and 20 illustrate another embodiment of an energy
element. In this embodiment, a catheter lumen comprises an
extrusion tube 121 that contains electrode wires 122 within the
wall of the extrusion tube 121. A plurality of windows 125 can be
provided at various positions along the extrusion tube 121 in order
to expose portions of the electrode wires 122. For example, such a
structure can be formed by extruding a tube around a pair of
electrode wires 122. The skived windows 125 can be formed during
the tubing molding process itself, by mechanical cutting or by a
secondary etching process. Mechanical cutting can include skiving
performed by selective cutting using a laser or water jet, for
example. FIG. 20 shows a cross section through the diameter of the
embodiment of FIG. 19.
[0150] FIGS. 21-22 show cross sections through the diameters of two
alternative embodiments of extrusions. As shown, the wires 122 can
extend longitudinally and substantially parallel to the extrusion
axis. These wires may be generally round (FIGS. 20 and 22) or
generally rectangular (FIG. 21) in cross section. Many other wire
cross-sectional shapes are possible which may be beneficial to the
design for flexibility and electrode configuration. The internal
lumen 186 is useful as the fluid cavity (see the fluid cavity 86 of
FIG. 10, for example). This lumen 186 can be used for temperature
sensors and other signal wires which can run internally to the
lumen but are not shown. These wires can run from the distal
working portion of the catheter to the proximal handle 14 and
connector 20 (see FIG. 1).
[0151] Alternatively, the wires 122 can wind helically through the
tube wall to promote overall device flexibility. FIG. 23 shows
schematically an example of a pair of helically wound wires
embedded within the tube extrusion wall. Two wires are used in this
example for clarity, but as in FIG. 22, multiple pairs could be
used. As discussed earlier, skived windows can be incorporated in
this extrusion to expose sections of the wire pairs in order to
create working electrodes.
[0152] The isometric view of FIG. 24 (an end view of which is shown
in FIG. 25) shows an example of multiple pairs of RF electrodes. In
this version, the pairs of electrodes can be multiplexed or
otherwise operated or controlled separately in pair-wise fashion,
in order to increase or vary the overall treatment length while
minimizing the power required for the treatment. This can be
facilitated by concentrating power to single electrode pairs in
subsequent order thereby providing heat to specific zones all at
once. Two zones are depicted, however more zones can be created
along the length of the device to provide longer overall treatment
lengths. Each portion can then treat a separate and discrete
section of the HAS to which that portion is adjacent via individual
control.
[0153] Yet another variation can be to have a common wire, which
has exposed section windows, and each of the other wires defines a
treatment length by its section of skived window electrodes. This
version typically reduces the number of wires required, yet the
device could nonetheless be operated in a multiplexed fashion, as
discussed above.
[0154] Any of the energy elements depicted in FIGS. 16-25 may be
incorporated into any of the embodiments of the HAS treatment
catheters disclosed herein (e.g., in any of the catheters of FIGS.
1-3, 4-5, 10-12, 13-15, 26) to deliver power to the fluid(s) at (or
to deliver both power and fluid to) the distal tips of those
catheters. Alternatively, any of these energy elements can be used
as stand-alone HAS treatment devices.
[0155] FIG. 26 shows another embodiment of an energy element
device. In this embodiment, an electrical element is housed within
an expandable balloon 131. Similarly to the above embodiments, a
dielectric tape 132 can be wound around a pair of electrodes 133
connected to an RF energy source (not shown) via signal wires 134.
(Only one electrode 133 is shown in this view, but a similar
electrode can be located opposite the depicted electrode 133.) The
electrodes 133 can heat a conductive fluid 135 confined within the
space created by the interior of the balloon 131 and the exterior
of the inner lumen 136. The conductive fluid 135 can also be used
to inflate the balloon 131. As the fluid 135 is heated by the
energy flowing through it, the heat can be transferred to a HAS in
which the device is positioned. This heat may be conducted into the
tissue of the HAS directly from the balloon 131.
[0156] In some preferred embodiments, the balloon 131 can be made
from substantially elastic materials such as silicone, or C-FLEX
(i.e. any of the family of materials manufactured and sold under
the trademark C-FLEX by CONSOLIDATED POLYMER TECHNOLOGIES, INC.
based in Clearwater, Fla.). These balloons are typically adjustable
in diameter and can expand to fit within many different HAS
diameters. Alternatively, the balloon can be made of PET or similar
inelastic materials which predefine the balloon size. The balloon
can be expanded or collapsed by at least one fluid port located on
the catheter shaft and inside the balloon section. This fluid port
can be configured to communicate with another lumen that runs
internal to the outer catheter shaft, and it can exit in the handle
14 (see FIG. 1) utilizing a luer-type connector for connection to a
fluid source.
[0157] As the balloon 131 is expanded, it can also displace any
fluid, such as blood, present in the immediate treatment area of
the HAS. This fluid displacement can facilitate treatment of the
HAS further by removing possible heat sinks and focusing the heat
more directly into the wall of the HAS.
[0158] The balloon 131 can further be configured to collapse as the
HAS itself is collapsing in response to the applied treatment. By
evaluating the amount of fluid forced out of the balloon at the
catheter handle, treatment success or completion can be indicated.
The balloon can be inflated with fluid so as to completely fill the
volumetric portion of the vein it is delivering treatment to. If
the fluid is then allowed to be squeezed out by the surrounding and
collapsing vein wall (typically via a release valve at the proximal
handle), then the amount of vein collapse can be determined by
correlating the ejected fluid volume with the reduction in the
internal volume of the treated HAS segment. Since HAS collapse is
indicative of a successful treatment, the amount of fluid released
at the proximal handle valve can be measured to indicate treatment
completion.
[0159] The balloon 131 can also be manually collapsed during the
last portion of the treatment cycle. This manual collapse can allow
the natural collapse of the HAS being treated.
[0160] Except as further described herein, the catheters of FIGS.
1-26 can, in some embodiments, be similar to any of the catheters
described in U.S. Pat. No. 6,401,719, issued Jun. 11, 2002, titled
METHOD OF LIGATING HOLLOW ANATOMICAL STRUCTURES. In addition, the
catheters of FIGS. 1-3, 4-5, 10-12, 13-15 and 16-26 may, in certain
embodiments, be employed in practicing any of the methods disclosed
in the above-mentioned U.S. Pat. No. 6,401,719. The entirety of
above-mentioned U.S. Pat. No. 6,401,719 is hereby incorporated by
reference herein and made a part of this specification.
[0161] Exemplary, but non-limiting embodiments of the devices of
FIGS. 1-9 can be constructed as described below. Some materials
that can be used are set forth in this list: polyimide tubing
(e.g., amber colored with an outer diameter of approximately 0.094
inches); computer ribbon wire from disk drive cable (two strands
with low-temperature insulation pulled away from ribbon);
insulation displacement connector (IDC) from disk drive cable; 36
AWG copper wire (two strands about 16 inches long); solder; Devcon
5-minute epoxy; Loctite UV adhesive (line stock); Tri-Arm (line
stock); two closed-end luer caps; IV extension tubeset (one male
and one female luer); cable assembly (strain relief cable, Lemo
connector, resistor, heat shrink tubing, black connector sleeve,
solder, epoxy, flux, etc.); saline (e.g., 0.9% isotonic saline); 5
cc or 10 cc syringe.
[0162] Some equipment that can be used is set forth in this list:
soldering iron; UV light source; ruler; razor blades; plastic
toothpicks; scalpel and blades; tweezers; cutting tweezers;
microscope; EFD dispensing tips; syringe (e.g., 3 cc); foam
swabs.
[0163] The following list and figures describe a procedure that can
be used for preparation and assembly of an embodiment of the
inventions described herein.
Exemplary Materials and Procedures
[0164] Preparation of RF Conductors: [0165] Cut the 2-stranded
computer ribbon cable to a length of 14 inches. [0166] Using the
IDC (Insulation Displacement Connector), begin regular punches of
the cable at one end. [0167] Continue using the IDC to make a
pattern of exposed portions of electrical conductors by alternating
the two rows of the IDC (line up the previous cut in one row of the
IDC connector and then compress the cutting blades to add a new
cut). FIG. 27 illustrates regularly-spaced cuts in the insulation
of the ribbon cable, next to a ruler to show approximately how
large the cuts are. [0168] Continue making alternately spaced cuts
on the insulation of the RF + and RF - conductors (spaced 0.050
inches apart) until the distal six inches of the ribbon cable is
treated with the IDC. [0169] On the proximal end of the ribbon
cable, split the two conductors and expose 2 mm of the conductor.
[0170] Cut the two pieces of 36 AWG copper wire to a length of 15
inches. [0171] Strip both ends of the wires using a razor blade to
expose 2-4 mm of copper conductor. [0172] Solder a copper wire to
each exposed (proximal) end of the ribbon cable. [0173] Using
two-part epoxy, coat the exposed portions of both solder joints.
Set aside to cure. [0174] Assembly of Shaft and Hub [0175] Cut the
polyimide tubing to a length of 11.5 inches. [0176] Threat the
ribbon cable into the polyimide tubing positioning the tip of the
active RF portion of the ribbon cable within 1-3 mm of the distal
end of the polyimide tubing. [0177] Do not allow the epoxy to flow
more than 3 mm into the tube. As the epoxy is curing, create a
rounded tip on the end of the polyimide tubing for an atraumatic
tip. [0178] Thread the proximal end of the polyimide and the copper
RF conductor wires into the distal end of the Tri-Arm. Thread the
two conductors down one of the side arms leaving the polyimide tube
in the main channel approximately 6-10 mm inside the Tri-Arm.
[0179] Using UV epoxy, wick adhesive between the polyimide tubing
and the Tri-Arm, taking care not to allow adhesive to block the
inlet to the polyimide tubing. Quickly, fully cure the adhesive
using the UV light source. [0180] Using the two-part epoxy, a 3 cc
syringe and 18G dispensing tip, inject glue into the side arm with
the wires to encase and seal the wires within the epoxy as shown in
FIG. 28. (Note: leave room at the exit of the side arm to attach
the cable assembly). Set aside to cure. [0181] Final Assembly
[0182] Integrate RF conductor wires into the cable assembly (using
strain relief cable, Lemo connector, resistor for Closure 1,
various heat shrink tubing for strain reliefs, black connector
sleeve, epoxy, solder, flux, etc., as shown in FIG. 29. [0183]
Attach the IV extension tubeset to the side arm (e.g., the
connector 20) of the Hub (e.g., the handle 14) (see FIG. 1). [0184]
Saline Priming the Device [0185] Fill a 5 or 10 cc syringe with
isotonic saline. [0186] Uncap the ends of both the central infusion
lumen and the end of the IV extension tubeset. [0187] Inject saline
into the central lumen of the Tri-Arm until most bubbles exit the
end of the IV extension tubeset. [0188] Cap the end of the IV
extension tubeset. [0189] Vary back and forth between injecting
saline under pressure and then aspirating by pulling back the
syringe until all of the bubbles within the polyimide tubing are
gone. [0190] Remove the syringe and cab from the central port of
the Tri-Arm without trapping any air in the Hub. [0191] The
following list describes materials that may be useful for bench
testing an embodiment of the inventions described above: [0192] The
medical device described above (referred to below as "RF
Generator") [0193] Catheter ID Bypass Box with Thermocouple Bypass
Circuit [0194] Two VNUS Instrument Cables [0195] Omega thermocouple
reader and thermocouple
[0196] The following list describes an example of a setup and
testing procedure and method for using embodiments of the
inventions described above: [0197] Equipment Setup [0198] Prepare
the RF generator for use by plugging in the generator. [0199] Plug
one instrument cable into the RF generator and the other end into
the bypass box. [0200] Plug the second instrument cable into the
bypass box and the self-regulating Hot Rod Device. [0201] Set the
bypass box's switch to Power Mode-this bypasses the thermocouple
(not installed on the prototype) and operates the RF Generator in
continuous power mode. [0202] Set the generator power to the
desired power setting. [0203] Plug the thermocouple into the Omega
Thermocouple Reader. [0204] Bench Temperature Testing Procedure
[0205] Uncap the end of the IV extension tubeset. [0206] Place the
tip of the thermocouple midway along the active RF portion of the
shaft. [0207] Turn the RF generator on and record the maximum
temperature achieved.
[0208] FIGS. 30-35 illustrate embodiments of heating element
devices configured to apply energy to a hollow anatomical structure
(HAS) by employing a capacitive structure. The devices of FIGS.
30-35 couple energy to the HAS without placing the electrical
elements in direct contact with the HAS wall through a process
known as dielectric heating. In some embodiments, devices can be
employed as the working section of an HAS treatment catheter, e.g.,
at the distal tip thereof or somewhere along the length of the
catheter shaft.
[0209] Many materials, both electrically conductive and
non-conductive, dissipate energy when subjected to an alternating
electric field through a process known as dielectric heating.
Dielectric heating generally works by causing rapid movement of
dipolar molecules (such as water) within a material by applying a
rapidly alternating electric field, thereby causing the dipolar
molecules to rapidly re-orient according to the orientation of the
field. The quantity of energy dissipated in the form of heat when
the material is placed in an alternating electric field depends on
a material property called a "dielectric loss factor." The
dielectric loss factor of a material is the product of the
Dielectric Constant of the material (Er) and the Loss Tangent (tan
.delta.) of the material.
[0210] Dipolar molecules have both positive and negative charges
separated by a small distance. When an electric field is created in
the vicinity of dipolar molecules, the molecules are forced to
align with the field. As the polarity of the electric field
alternates, the dipolar molecules rotate to align to the new field
orientation. This rapid movement of the molecules effectively heats
the material by internal friction. Thus, materials with more polar
molecules will tend to have higher dielectric loss factors than
materials with fewer polar molecules. Non-polar materials such as
fat and dry tissue do not react to the electric field, and
therefore, are not directly heated by capacitive RF energy.
[0211] In a typical good quality, low loss capacitor used in
electronic applications, it is desirable to reduce the effects of
dielectric heating. Thus, the dielectric materials of such
capacitors typically have relatively low dielectric loss factors as
a result of a high dielectric constant (i.e., a higher number of
molecules that react to the electric field) and a small loss
tangent (i.e., a measure of how much energy is lost to molecular
friction). However, in situations where it is desirable to heat the
dielectric material, the dielectric material preferably has a
relatively large loss factor as a result of a larger loss tangent.
In both cases, the dielectric material preferably includes a
sufficiently high dielectric constant to achieve the desired degree
of capacitance.
[0212] The degree of the dielectric heating effect depends upon the
frequency of the AC power used, the RF voltage field and the loss
factor of the material being heated. The equation shown below
determines the heating effect: P.sub.d=2 .pi. f
(.epsilon..sub.r.epsilon..sub.0) tan(.delta.) E.sub.rms.sup.2
[0213] From this expression, it is apparent that power dissipation
in the dielectric material increases proportionally with frequency,
dielectric constant, and loss tangent.
[0214] Unlike polymeric and ceramic materials used for making most
capacitors for electronic applications, the dielectric properties
of biological materials change more rapidly with changing
frequency. For example, as illustrated in the following table,
dielectric constant (.epsilon..sub.r) and loss tangent (tan.delta.)
increase at increasing applied frequencies: TABLE-US-00002 Blood
Blood Saline Saline Blood Blood Vessel Vessel Frequency
.epsilon..sub.r tan.delta. .epsilon..sub.r tan.delta.
.epsilon..sub.r tan.delta. 100 kHz 98 2752 5120 25 930 62 500 kHz
91 593 4195 6 313 37 1 MHz 84 323 2997 5 216 27 10 MHz 70 39 277 7
110 6
[0215] Applying the earlier formula for volumetric heating using
the values in the preceding table, and using an electric field
strength of 10,000 V/m yields: TABLE-US-00003 Saline Blood Blood
Vessel (Pd) (Pd) (Pd) Frequency (w/cm.sup.3) (w/cm.sup.3)
(w/cm.sup.3) 100 kHz 150 71 32 500 kHz 150 70 32 1 MHz 151 83 32 10
MHz 152 108 37
[0216] Thus, as shown above, with all other things being equal, the
highest dissipation of heat occurs in saline, and then in blood,
with heat dissipation to the vessel wall occurring the slowest.
[0217] Radiofrequency generators will generally output power
efficiently over a finite range of impedance and phase angle. If
the source and the load impedances are not matched, a reduced
amount of power is transmitted from the source to the load. In the
case of dielectric heating, the load is represented by the parallel
resistance created by the properties of the capacitor, i.e.,
dielectric constant and loss tangent.
[0218] Dielectric resistivity manifests itself both as a series and
a parallel resistance with the pure capacitance. Generally, a low
series resistance and high parallel resistance. The impedance
presented to the RF generator is then the parallel impedance of the
Rp and Cp in series with the series resistor, Rs. Since this
impedance varies with frequency, either steps to match the
impedance with the RFG should be performed, or an operating
frequency should be selected to match the impedance of the circuit.
Coupling the electric field through the dielectric is generally
easier when operating at higher frequencies, because the impedance
experienced by the capacitive device is lower at higher
frequencies.
[0219] FIGS. 30-35 illustrate embodiments of devices capable of
coupling an electric field into an HAS surrounding or adjacent the
devices. The devices 500, 550, 600, 650 generally comprise an
elongate structure having at least one pair of electrodes 510A,
510B, 560A, 560B, 560C, 560D, 610A, 610B, 660A, 660B, 660C, 660D,
660E, surrounded by an insulative sheath 515, 565, 615, 665 which
substantially prevents direct conduction of electrical energy into
surrounding fluid or tissue. For example, as shown in the
embodiment illustrated in FIGS. 30-31, the electrodes 510A, 510B
are generally arranged to form one or more capacitive electric
fields. When an electric field is applied across the electrodes,
portions of the field will extend radially outwards from the
device. Thus, by rapidly alternating the polarity of the field, the
dipolar water molecules in the adjacent surrounding fluid and
tissue will be heated by dielectric heating. The shape and extent
of the electric field can be varied by adjusting the physical
geometry of the device and/or by varying electrical properties
(e.g. field voltage, frequency, power, etc.) of the device 500 or
power supply. Heating will generally stop when the fluid or tissue
within the electric field becomes sufficiently desiccated that the
electric field no longer interacts with water molecules. In this
way, depth of heating penetration can be limited.
[0220] The electrodes 510A, 510B, 560A, 560B, 560C, 560D, 610A,
610B, 660A-E are preferably separated by electrically
non-conductive, insulative segments 520, 570, 620, 670. For
example, as shown in FIG. 30, the insulative segments 520 between
the electrodes 510A, 510B can be any suitable material as desired
(including air). In many embodiments, the material separating the
electrodes 510A, 510B preferably has a substantially low dielectric
constant, and a substantially low loss tangent relative to the same
properties of the tissue to be treated. For example, in one
embodiment, the tissue to be treated is a blood vessel with a
dielectric constant of about 70, and a loss tangent of about 39. In
one such an embodiment, a material with a dielectric constant of
less than about 10 and a loss tangent of less than about 5 would be
desirable. In alternative embodiments, materials with larger
dielectric constants and/or loss tangents could also be used. In
some embodiments, for example, as shown in FIG. 30, the device 500
can comprise a substantially solid section 525 of an electrically
non-conductive material such as PEEK, Pebax, Polyimides, nylon,
polyurethane, PTFE, or another suitable electrically non-conductive
material. In alternative embodiments, for example, as shown in FIG.
32, the device 550 can comprise one or more substantially hollow
lumens 575 to provide internal space for a guidewire, fluid
infusion, optical fibers, or another purpose. In some embodiments,
the device can include a partial separator between the electrodes,
thereby dividing the internal space into two or more parallel
lumens.
[0221] The outer non-conductive sheath 515, 565, 615, 665
surrounding the electrodes preferably are made of a material that
is substantially electrically non-conductive, yet is substantially
"invisible" to the RF field at the applied frequency. For example,
many polymers will have sufficiently few dipolar molecules as to be
substantially unaffected by the alternating electric field across
the electrodes elements. It is believed that, at sufficiently high
frequencies (e.g., about 10 to about 30 MHz), materials such as
PET, PTFE, FEP, PE Polyolefin (or other materials with dielectric
constants and loss tangents that are appreciably less than the same
properties of the biological structure to be treated) will be
substantially unaffected by RF power in the electrodes. The
thickness of the outer sheath is typically minimized to
substantially limit the amount of heating experienced by the
sheath, yet remains thick enough to provide adequate electrical
insulation and to resist melting due to contact with the heated
tissue.
[0222] FIGS. 30 and 31 illustrate one embodiment of a capacitively
coupled thermal element 500 which generally comprises first 510A
and second 510B electrodes separated by an insulating section 520,
such as an air gap or a section of an insulative material. For
example, in one embodiment, the first 510A and second 510B
electrodes comprise elongate sections of semi-cylindrical
electrically conductive elements. The device 500 of FIGS. 30 and 31
will couple an electric field 530 into the tissue with electric
field lines extending radially around the device 500. Thus, heating
will occur along the contour lines of electric field, which are
strongest along the plane 535 separating the first 510A and second
510B semi-cylindrical electrodes. Thus, in one embodiment, the
device 500 of FIGS. 30 and 31 is rotated during use (e.g., when the
electric field 530 is being generated) along its axis in order to
apply even heating to the surrounding HAS tissue and/or fluid.
[0223] In an alternative embodiment, illustrated for example in
FIGS. 32 and 33, four or more elongate electrodes 560A, 560B, 560C
and 560D can be provided around the circumference of the device
550. The four sections 560A-D can be connected to a power supply
with alternating polarity. For example, the segment at 12 o-clock
to 3 o-clock and the segment at 6 o-clock to nine o-clock can be a
positive polarity when the segments at 9-12 o-clock and 3-6 o-clock
are negative. Such a device will generally form electric field
lines 580 along multiple planes as shown in FIG. 33, thereby
providing heating around more of the circumference of the device.
In some embodiments, the electrodes 560A-D may extend linearly
along a catheter, thereby forming one or more substantially planar
areas of maximum field strength. The electrodes of FIGS. 30-33 are
shown as cylindrical sections. However, the electrodes can comprise
any other cross-sectional shape as desired, such as planar,
rectangular, triangular, etc.
[0224] In an alternative embodiment, illustrated for example in
FIG. 34, the electrodes can be wound around the catheter in a
helical pattern, or otherwise coiled around the catheter shaft.
Wrapping the first 610A and second 610B electrodes in a helical
pattern along the device provides a number of advantages. For
example, the helical pattern of maximum field strength achieved
with a pair of helically wound electrodes can create a more uniform
distribution of energy around the circumference of the device and
along the length of the device. The spacing between adjacent
windings can be adjusted in order to achieve a desired field
pattern and energy distribution. Additionally, helically wound
electrodes will typically offer more flexibility and
maneuverability to the device than linear electrodes.
[0225] In some embodiments, the electrodes extend along
substantially an entire desired working length. For example, in
some embodiments, the electrodes can have an operative length of
anywhere from one to sixty cm. For example, in some embodiments,
total working lengths of 9 cm, 15 cm, 30 cm, 45 cm or other lengths
can be used as desired. In some embodiments, variable length
treatment devices may be constructed by providing a plurality of
discrete segments along the axis of the device. The operative
length of the device can then be varied by activating or
de-activating one or more pairs or sets of discrete segments as
desired.
[0226] The elongate electrodes can be made of any suitable
material, such as copper or other conductive metallic tape, etched
flex circuits, metalized polymer substrates (e.g., formed by vapor
deposition or other process). In some embodiments, a metallic tape
can be co-extruded into an elongate catheter. In some embodiments,
the electrodes are preferably substantially flexible to allow the
device to be guided to a desired treatment site.
[0227] FIG. 35 illustrates another embodiment of a capacitively
coupled HAS heating element 650 comprising a plurality of
axially-separated rings 660A-E. The rings 660A-E are joined to a
power supply in an alternating positive/negative manner, such that
electric fields 670 can be created at the junctions of the rings
660A-E. Thus, an operative length of the device 650 can be varied
by applying RF power to a select number of rings 660A-E along a
desired length or section of the device 650. If desired, the device
650 can be pulled and/or pushed axially in order to increase
uniformity of heating the HAS wall.
[0228] Embodiments of methods for using devices such as those
illustrated in FIGS. 30-35 will now be described. In one
embodiment, a device having a plurality of elongate electrodes is
inserted into an HAS and guided to a desired treatment site. Once
the heating element of the device is positioned at the treatment
site, RF power can be applied to the electrodes. The device can be
rotated about its longitudinal axis and/or pushed or pulled axially
in order to provide even heating of the HAS wall. In some
embodiments, the device can be pulled proximally or pushed distally
during treatment in order to affect a section of the HAS longer
than the operative section of the device. In alternative
embodiments, the power supplied to the heating element can be
stopped before re-positioning the device in a different section of
the HAS, or in a different HAS altogether. Once the device is
re-positioned, power can again be supplied to the heating element
for treatment of the new site.
[0229] In some embodiments, any of the devices of FIGS. 30-35 may
have multiple, separately operable electrodes or separately
operable electrode pairs (e.g. each electrode/pair having a
separate power delivery conductor or otherwise being separately
addressable for power application). Thus, when used with an
appropriate control system, subsets of the available
electrodes/pairs can be operated sequentially in a "multiplexed"
fashion (e.g., similar to the multiplexed mode of operation
depicted in FIG. 41 and described below). Any of the techniques or
modes described below for multiplexed operation of electrodes can
be used in conjunction with any appropriate embodiment depicted in
FIGS. 30-35 when multiple, selectively or separately energizable
electrodes/pairs are provided as part of the device. The devices
may therefore include a control unit configured to sequentially
energize selected subsets of the entire set of electrodes/pairs on
the shaft. The control unit may include an appropriate multiplexing
or sequential-operation algorithm (e.g., program instructions)
stored in memory and executable by a processor of the control unit,
to selectively operate the electrode/pair subsets as desired.
[0230] The devices of FIGS. 30-35 advantageously have very simple
constructions requiring no moving parts. These devices can also
advantageously provide substantially long working sections, thus
requiring minimal movement of the device during treatment. The
devices of FIGS. 30-35 also advantageously reduce the need for
physical contact between the device and the HAS wall, and
substantially reduces the need for the device to be centered within
the HAS.
[0231] Although many of the forgoing embodiments have been
described in the context of treating a hollow anatomical structure
(such as a blood vessel), it should be understood that the above
embodiments are not necessarily limited to such uses. For example,
the systems and devices described herein can be used for any
clinical procedure in which it is desirable to apply energy to
anatomical, biological, or foreign structures within a patient.
[0232] In some respects, some embodiments of the devices described
herein may be similar to one or more of the catheters described in
U.S. Pat. No. 6,401,719, issued Jun. 11, 2002, titled METHOD OF
LIGATING HOLLOW ANATOMICAL STRUCTURES. In addition, the devices
described herein may, in certain embodiments, be employed by
practicing any of the methods disclosed in the above-mentioned U.S.
Pat. No. 6,401,719, the entirety of which is hereby incorporated by
reference herein and made a part of this specification.
[0233] The features of a system and method having electrode
elements will now be described. The drawings, associated
descriptions, and specific implementation are provided to
illustrate embodiments of the invention and not to limit the scope
of the invention. In addition, methods and functions described
herein are not limited to any particular sequence, and the acts or
states relating thereto can be performed in other sequences that
are appropriate. For example, described acts or states may be
performed in an order other than that specifically disclosed, or
multiple acts or states may be combined in a single act or
state.
[0234] FIG. 36 illustrates an embodiment of an RF element system
for applying energy to the wall of a hollow anatomical structure
such as (but not limited to) the inner wall(s) of a vein, e.g. a
varicose vein. As illustrated, the RF element system comprises a
catheter 700. The catheter 700 includes a catheter shaft 703, which
may be used to maneuver the distal or working portion 704 of the
catheter 700 during placement. In one embodiment, the catheter
shaft 703 comprises a biocompatible material having a low
coefficient of friction. For example, the shaft 703 may comprise a
polyimide. In other embodiments, the shaft 703 may comprise
Teflon.RTM., Hytrel.RTM., or any other such suitable material. In
one embodiment, the catheter shaft 703 is sized to fit within a
vascular structure that may be between 2 and 14 French, but
preferably between 4 and 8 French, which corresponds to a diameter
of between 1.3 mm (0.05 in) and 2.7 mm (0.10 in), or other sizes as
appropriate. The distal portion 704 transfers energy (e.g., RF
energy where the distal portion comprises one or more RF
electrodes) to an inner vein wall. The proximal end of the catheter
has a handle 705. The handle 705 includes a port for fluid and a
connection 706 for interfacing with an energy source 702.
[0235] In one embodiment, an energy source 702 comprises an
alternating current (AC) source. In other embodiments, the energy
source 702 comprises a direct current (DC) power supply, such as,
for example, a battery, a capacitor, or other energy source. In
some embodiments, the energy source 702 preferably comprises an RF
generator powered by an AC or DC supply. The power source 702 may
also incorporate a controller that, by use of a microprocessor,
applies power using a temperature sensor located in the working
portion of the catheter 700. For example, the controller may heat
the tissue of a hollow anatomical structure to a set temperature.
In an alternate embodiment, the user selects a constant power
output of the energy source 702. For example, the user may manually
adjust the power output relative to the temperature display from
the temperature sensor in the working portion of the catheter
700.
[0236] FIG. 37 illustrates another embodiment of an RF element
system similar to the embodiment of FIG. 36 except as described
below. As shown, the catheter 710 includes an outer retractable
sheath 712. The sheath 712 is advantageously used to protect the
device during placement, facilitate introduction of the device,
and/or adjust the exposed axial length of the electrode element for
a user-selected and variable treatment length. For example, the
sheath 712 may be used (e.g., pulled back (proximally) or pushed
forward (distally)) to adjust the length of the region of the
catheter that is exposed to a wall of the hollow anatomical
structure.
[0237] In some embodiments, the catheter 710 has an internal lumen.
The lumen preferably communicates between the distal tip and the
proximal handle. The lumen may be used for fluid delivery such as
saline, a venoconstrictor, sclerosant, high-impedance fluid,
adhesive, hydrogel, or the like. In one embodiment, the catheter
lumen can be used to apply a venoconstrictor prior to treatment
with the electrode element. Application of a venoconstrictive agent
to an interior portion of a hollow anatomical structure, e.g., a
vein, can improve the apposition of the energy applying device to
the structure wall. Venoconstrictive agents, when suitably applied,
rely on the body's own physical reaction to the agent to contract
and collapse around the therapeutic device.
[0238] The venoconstrictive agent preferably is easily applied over
the target treatment length to enhance the performance of the
device. The venoconstrictive agent preferably is non-toxic, well
tolerated, effective in both sedated and non-sedated patients, and
substantially free of adverse side effects. The venoconstrictive
agent preferably is metabolized relatively quickly. Some
embodiments comprise one or more of the following exemplary
venoconstrictive agents: phenyl ephrine, high-concentration K+
solution, sumatriptan, dihydroergotamine, 5-hydroxytryptamine (or
an equivalent that can bind to 5-HT1 receptors found in the
saphenous vein), and other suitable agents.
[0239] In one application, the venoconstrictive agent is
administered by direct injection to the interior of the hollow
anatomical structure. In other applications, the venoconstrictive
agent can be administered by superfusion to the exterior surface
via injection, by systemic injection, or by other suitable methods.
Application of the venoconstrictive agent may be made through the
energy delivering device (e.g., the catheter 710), through another
specialized delivery device, or through a nonspecialized delivery
device. In some embodiments, occlusive methods, e.g., manual
compression surrounding the area of interest, the use of a balloon,
insertion of bioabsorbable occlusive elements or adhesives, can be
used to locally isolate the venoconstrictive agent.
[0240] External physical and/or manual compression can also improve
the apposition of the energy applying device to the structure wall.
Compression methods can include external mechanical means to
achieve compression, such as, for example, tumescent anesthesia,
manual compression, vessel collapsing mechanisms that include
spreadable opposed elements, reciprocating jaw mechanisms having
penetrating elements, and devices for applying negative pressure to
collapse the blood vessel.
[0241] Reducing the intra-luminal diameter of the vein can decrease
the distance between the vein wall and the energy delivering device
to increase the efficiency and uniformity of energy delivery to the
vein wall. The vein can then be treated with the RF electrode
element to further shrink the vein.
[0242] Upon completion of treatment, a hydrogel may be exuded from
the distal catheter end allowing for complete vessel occlusion. For
example, the hydrogel may be biocompatible or bioresorbable. In
other embodiments, the hydrogel may be displaced by the
constriction of the hollow anatomical structure resulting from the
thermal injury response which results in substantially complete
occlusion. In those sections of the hollow anatomical structure in
which the material has not completely compressed, it can be
resorbed by the body naturally. In yet other embodiments, the lumen
may also accommodate a guide wire for catheter placement.
[0243] FIG. 38 shows another embodiment similar to the embodiments
described and depicted in FIGS. 36-37 above, except as noted below.
A catheter 720 comprises a temperature sensor 722 as part of the
electrode. In other embodiments, multiple sensors are placed along
the axial electrode length. In some embodiments, the energy source
can advantageously monitor individual sensors and use the multiple
inputs for temperature feedback. In another embodiment, the
controller may monitor for high temperature or low temperature
signals. For example, an algorithmic process may be used to control
the electrodes, thus maintaining a substantially axially-uniform
temperature and/or heat output.
[0244] Some embodiments comprise a multi-ball configuration
employed with or without a multiplexing process. For example, FIG.
39 illustrates one embodiment of the working end 750 of a catheter
such as the catheter shown in FIGS. 36 and 37. The working end 750
comprises separate distinct protruding electrode elements 752
preferably comprising non-corrosive and biocompatible materials
such as, for example, stainless steel or platinum. To improve the
tissue heating by the electrode, the protruding elements 752
preferably are hemispherically shaped. In other embodiments the
protruding elements can be other suitable shapes. The elements 752
preferably are spaced axially along the catheter shaft 754. In the
illustrated embodiment, each element 752 preferably is attached to
a signal wire by solder or spot weld. The signal wire, not shown,
preferably is placed internal to the catheter tube and attached to
the connector 706, as shown in FIG. 36. One or more temperature
sensors can be positioned on or near one or more of the
electrodes.
[0245] In some embodiments, one or more electrode elements can be
temperature controlled by having a temperature sensor as shown in
FIG. 38 in a monopolar mode. In other embodiments, one or more
pairs of electrodes can be temperature controlled in a bipolar mode
by having a temperature sensor located on or near one or more of
the electrode pairs. In another embodiment, the sequential
electrode elements are used in a power control mode relying on
manual energy control.
[0246] Alternatively, in one embodiment having multiple electrode
elements, a temperature sensor is located on the most distal
electrode. For example, the most distal electrode may be used for
the initial treatment profile, and the successive electrode pairs
may use the same and/or a predetermined energy-time profile.
[0247] In one embodiment, a method of use of the RF electrode
element system 760, which is similar to the system described with
reference to FIG. 39, except as noted below, includes multiplexing
through each of the electrode elements 761-768 shown in FIG. 40.
The term "multiplex" as used herein is a broad term and is used in
its ordinary sense and includes without limitation the energizing,
or heating, of at least one active electrode element for a specific
dwell time and cascading, or moving to another active electrode
element until the end active electrode element is reached or until
a cycle is completed. The cycle is then repeated until the complete
treatment time is reached.
[0248] Each tissue section adjacent to an electrode preferably is
kept at the treatment temperature by cycling through the electrode
sequence within a defined time. With reference to FIG. 40, the
electrode element configuration has eight active electrodes. In the
illustrated embodiment, active electrodes 761 through 768 are
indicated as having positive (+) polarity and the other nine return
electrodes are indicated as having negative (-) polarity. The
indicated polarity is merely exemplary. Where the energy source 702
comprises an AC source there is not really a polarity, but the
indication of polarity is helpful to identify the active and return
electrodes in the illustrated embodiment. Each of the active
electrodes has two adjacent return electrodes. This is to increase
and spread the RF tissue heating length and to create a uniform
treatment length via an overlapping mechanism. In one embodiment,
the return (-) electrodes are sequenced so that the relevant ones
are `on` when the adjacent active (+) electrodes are `on.` In
another embodiment, the return (-) electrodes are `on` as a group,
working with the relevant energized active (+) electrodes.
[0249] In one embodiment, the electrode elements 760 through 768
are sequentially energized for a dwell time of 0.2 seconds. In the
example shown, three electrode elements are powered at a time. The
table in FIG. 41 has shaded blocks of time, which represent the
time that energy is being delivered to the specified active
electrode elements. Since three electrode elements are on at one
time, and the dwell time is 0.2 seconds, each electrode element is
on for a total of 0.6 seconds during one cycle. In the table, for
time 0 to time 0.2 seconds, electrode elements 761, 762 and 763 are
energized. For time 0.2 seconds to 0.4 seconds electrode elements
762, 763 and 764 are energized. This process repeats by stepping
through the electrode element set. For the 8 active electrode
elements shown, one complete cycle takes 1.6 seconds.
[0250] In one embodiment, to avoid overcooling of a particular
electrode element, the cycle time for the 8 active electrodes is of
a short duration and/or the total number of electrode elements is
limited. That is, in one embodiment, an electrode element may be
re-energized before substantial cooling takes place. In addition,
in one embodiment, to increase the treatment zone, the catheter may
comprise multiple treatment zones, such as, for example, groups of
eight electrode elements, as is shown in FIG. 41. Each group of
eight electrode elements may treat the wall of the hollow
anatomical structure before energy is applied to the next group of
electrode elements. Alternative modes of multiplexing may also be
employed. For example, the number of adjacent electrode elements
simultaneously energized may vary. Also, the entire cycle may
re-start at the first end energized, or the last end energized.
Another mode of multiplexing may be accomplished through a sensing
of the tissue impedance. Once a certain level is achieved, the next
set of electrode elements is then energized.
[0251] Alternatively, at least one of the eight active electrode
elements is energized to treat the hollow anatomical structure
until treatment is complete. Then, the next active electrode
element(s) apply a similar treatment time, and so on moving along
the treatment zone. For the eight active electrode elements
illustrated in FIG. 40, the treatment may be for one cycle. For
example, active electrode element 761 may treat the hollow
anatomical structure for 40 seconds. Once electrode element 761 has
completed treatment, electrode element 762 repeats the same
treatment time and energy settings. Such a process may continue for
active electrode elements 763 through 768.
[0252] In other embodiments, alternate treatment cycles may be
used. For example, active electrode elements 761 and 762 may
concurrently treat the hollow anatomical structure for 40 seconds.
Then, active electrode elements 763 and 764 apply a similar
treatment, and so forth through active electrode elements 767 and
768 to complete the cycle.
[0253] FIG. 42 is another embodiment of the working portion of the
catheter of FIG. 39. The device 780 has a balloon 782. The balloon
782 preferably is expandable by internal ports to the balloon. The
illustrated device has one balloon located at one end of the
electrode set. Additional fluid ports 784 proximal to the electrode
elements 752 are preferably provided for fluid placement within the
hollow anatomical structure.
[0254] In one embodiment, the catheter 780 is placed in the hollow
anatomical structure, and then the balloon 782 is inflated through
the internal ports. Once the balloon is inflated and in apposition
to the vein wall, the fluid ports 784 preferably clear the
treatment zone of the hollow anatomical structure of native fluid,
such as blood, distal to the balloon 782, by injecting displacing
fluid, such as, for example, saline. In one embodiment, the
displacing fluid is followed by another injection of a
venoconstrictor, which reduces the hollow anatomical structure
lumen size prior to treatment. By temporarily reducing the hollow
anatomical structure's size, the treatment time used for the active
electrode elements 752 is reduced, thereby resulting in a shorter,
safer and more effective treatment. Additionally, in one
embodiment, constricting the hollow anatomical structure
exsanguinates it of blood, enhancing the functionality of the
device by reducing coagulum formation and promoting a better
long-term efficacy by reducing the thrombotic occlusion.
[0255] In another embodiment, the device has a balloon at each end
of the electrode set. The proximal balloon is inflated. A
displacing fluid (as discussed above) is delivered using the fluid
ports 784. The distal balloon preferably is partially inflated
prior to fluid delivery and then fully inflated after fluid
delivery to help isolate displacing fluid within that section of
the hollow anatomical structure.
[0256] With reference to FIG. 43, one embodiment of an RF system
800 uses at least one expandable spline. The pre-shaped splines
802, six splines in this figure, act as individual electrode
elements. The set of splines 802 are attached radially about the
catheter shaft 804. The expandable electrode element set has at
least one expandable section. In FIG. 43, the device shown has two
expandable sections 806, 808. The electrode element set is anchored
at the mid point 810, which does not substantially expand. The tip
812 and proximal end 814 attached to the shaft 804 also do not
substantially expand.
[0257] In some embodiments, one or more electrode splines comprise
one or more electrode elements. In one embodiment, a bipolar device
comprises a plurality of electrodes on one or more splines. In
another embodiment, a bipolar device has a plurality of splines
having opposite polarities. In one embodiment, the electrode sets
of each spline preferably are staggered relative to one another to
form a checkerboard-like pattern. The checkerboard-like pattern
preferably limits the likelihood that the electrodes will contact
each other in the collapsed configuration. The exposed electrode
portions preferably are positioned on the outer surface or face of
the spline to contact a vein wall.
[0258] The device is designed to collapse by use of an outer
sheath, which in FIG. 43 is in a retracted position. For example,
the sheath may be used to help place the device in the vessel and
to help remove the device after treatment. In another embodiment,
the sheath is used to limit the treatment length. For example, a
physician using an embodiment of the device having four segments
can limit the treatment length by selectively deploying less than
four segments from the sheath for treatment.
[0259] The self-adjusting splines preferably allow an appropriate
amount of expansion for apposition to the tissue, while adjusting
axially to bends or curves in the hollow anatomical structure. As
the hollow anatomical structure is heated during treatment, the
lumen preferably constricts and/or shrinks. The spline set
preferably adjusts and collapses concurrently with the hollow
anatomical structure. This same characteristic also gives the
device of FIG. 43 versatility, as it is able to accommodate varying
diametrical sizes of hollow anatomical structures.
[0260] Alternatively, the device comprises a stylet wire attached
to the distal tip and placed axially and internally to the catheter
in order to collapse and expand the pre-shaped splines. In this
embodiment, the splines may be manually collapsed during treatment
to duplicate the collapse or lumenal reduction of the hollow
anatomical structure.
[0261] In some embodiments, each spline 802 is made of a spring
type material such as Nitinol.RTM.. Other nickel based spring
alloys, stainless spring alloys, 17-7 stainless, Carpenter 455 type
stainless, or other non ferrous alloys such as beryllium copper can
also be used. A temperature sensor can also be attached to one or
more splines for temperature controlled energy delivery. Each
spline 802 thus comprises a conductor which is covered in
insulation over most of its length. To form one or more electrodes
the insulation is skived away from portion(s) of the outward-facing
surface of the spline(s) to selectively expose the underlying
conductor.
[0262] In the embodiment illustrated in FIG. 44, another embodiment
of an RF system 820 is shown, one long expandable section makes up
the expandable spline set 822. The spline set 822 preferably
comprises splines having one or more electrode elements 826. To
support the length during treatment, a balloon 824 is placed inside
the spline set and is shown in FIG. 44. For example, this balloon
824 may use an internal lumen of the catheter (not shown) for
inflation and deflation. Alternatively, the balloon 824 can be a
separate device inserted into the long expandable spline set 820.
Alternatively, open cell foam can be used in place of the balloon
as the expanding component. The foam can be collapsed by a sheath,
and by sliding the sheath proximally, the foam could expand as it
is uncovered.
[0263] As discussed above with respect to the fixed diameter
electrode element systems, spline electrode elements, when
individually wired for power, may be used in conjunction with a
multiplexing process. Such an embodiment allows for the sequential
or "cascading" heating of specific active electrode element subsets
of the spline set. This may involve energizing at least one spline
for a specific dwell time and then cascading axially or moving to
the next adjacent spline(s) or electrode element(s) until the end
spline or electrode element is reached. The cycle is then repeated
until the complete treatment time is reached. Multiplexing can be
used with monopolar or bipolar configurations of electrode element
subsets. For a monopolar mode, a ground pad or virtual electrode is
used in conjunction with active spline electrodes powered by the
multiplexer. For a bipolar mode, adjacent electrodes on each spline
are powered for treatment along each spline. In another embodiment,
adjacent splines are bipolar so that spline pairs treat the vein
along the spline length. In one embodiment, an active spline and
two return splines are powered to treat the hollow anatomical
structure.
[0264] A balloon can also be used to expand and collapse the
electrode elements. The balloon preferably displaces blood from
lumen being treated and can reduce the amount of coagulum build-up
on the inside of the heating element. Minimizing coagulum build-up
during the collapse and removal of the device is advantageous. In
one embodiment, the balloon occludes the vessel, impairing blood
flow and subsequent coagulum build-up to facilitate device removal.
The balloon can act as a support structure for the outer electrodes
to enhance vein wall apposition.
[0265] FIG. 45 is another embodiment of the working end 850 of a
catheter, using one or more expandable splines 852 in spline sets
854. In the illustrated embodiment, the splines 852 are
cantilevered, being attached to the catheter 856 at one end. The
cantilevered electrode preferably is only active at the distal tip
portion. The arm of the electrode is electrically insulated. The
pre-shaped spline sets 854 are axially spaced apart. A sheath cable
used to control the collapsed and expanded positions of the
electrodes. The sheath can also be used for placement and removal
of the device. In some embodiments, it can be used to set the
treatment length. For example, where there is more than one set of
splines on the device, the sheath can be selectively withdrawn to
expose a desired number of spline sets to treat a desired length of
tissue.
[0266] A temperature sensor can be placed on the distal end of the
cantilevered spline electrode. In some embodiments, the sensor can
be used with the RF power controller described above. The
temperature sensor preferably is placed proximal to the treatment
zone. In some embodiments the device is used such that the
electrodes move or are `pulled back` during treatment. Using
multiple electrode sets preferably reduces the treatment time
required. In other embodiments, the device is used in a stationary
manner and subsequently moved to another section of the hollow
anatomical structure for another treatment.
[0267] FIG. 46 shows another embodiment 860, similar to the
embodiment of FIG. 45. In this embodiment, the spline sets 864 are
configured for monopolar RF. The spline sets 864 are one polarity
and a ground pad 866 is used to create the return path through the
patient. By using multiple electrode sets, the treatment length can
be longer.
[0268] FIG. 47 shows another embodiment 870 of the device of FIG.
45. The spline sets 874 are arranged for bipolar RF. In this
embodiment, each electrode spline set 874 has a different polarity
from an adjacent electrode spline set.
[0269] The embodiments illustrated in FIGS. 45-47 can be used in
conjunction with the multiplexer process when used in a stationary
manner.
[0270] With reference to FIG. 48, in one embodiment the device 900
has expandable-cantilevered electrodes 902 similar to those
described above. The device has one or more electrodes 902 in one
or more sets of electrodes 904. Proximal to the electrode sets 904
is a sheath-mounted heating element 908 (e.g., a resistive coil).
The proximal heating coil preferably initiates the treatment
process and the expanded electrodes preferably complete the
treatment process. The effective length of the proximal coil
element can be controlled by the use of a sheath component similar
to that described above with reference to FIG. 37.
[0271] One or more temperature sensors can be placed on the distal
end of the cantilevered spline electrodes. The device of the
illustrated embodiment can be used with an RF power controller
similar to that described above. The temperature sensor preferably
is placed proximal to the treatment zone. The device can be used
such that the device-electrodes move during treatment. Using
multiple electrode sets preferably reduces the treatment time.
[0272] Another embodiment of a device 950 shown in FIGS. 49-50
utilizes at least one expandable loop 955 which emanates from the
side of the main catheter body. One end 959 of the loop 955 is
anchored to the catheter shaft 953. The other end of the loop
passes through an opening 956 in the sidewall of the catheter tube
953 and extends through the catheter lumen to the handle (not
shown) at the proximal end. This proximal end of the loop acts like
a stylet, and is usable to manipulate the loop shape and size. FIG.
49 shows the loop 955 in an expanded or erected configuration
suitable for HAS treatment, and FIG. 50 shows the loop 955 in a
collapsed or low-profile configuration suitable for passing the
device 950 through the HAS. The wire is typically circular in cross
section. In one embodiment, the loop is pre-shaped in order to
extend outward toward the walls of the hollow anatomical structure
and eventually into contact with them. Alternatively the wire
section that forms the actual exposed loop portion 954 may be a
flat wire, rectangular, ovular, or other geometrical cross section.
In one embodiment, rotating the stylet handle end of the loop
manipulates, or twists, the loop toward or away from the catheter
shaft.
[0273] In one embodiment, each loop preferably is individually
erectable or powered to match varying hollow anatomical structure
diameters providing tailored treatment parameters. In one
embodiment, all loops can be of the same length/diameter and can be
actuated simultaneously.
[0274] The loop 955 may comprise an electrode element similar to
the initial embodiment of FIG. 43. For example the loop 955 may
comprise active electrode elements 957 located thereon. In
addition, each loop may have a temperature sensor on the active
electrode element for use in temperature controlled energy
delivery. In other embodiments, the active electrodes are of one
polarity and use a ground pad as the return electrode for a
monopolar setup.
[0275] In one embodiment, the active electrodes are bipolar (e.g.,
comprising a positive and negative pain) on the loop itself. Each
loop is used to treat a section of the vein. The number of loops
expanded determines the treatment length enabling the device to be
adjusted to provide a variable treatment length. In some
embodiments, the device is moved and newly placed to treat the
adjacent vein wall relative to the initial treatment.
[0276] FIGS. 51-54 show various views of an expandable foam
component 1000. The foam preferably is conformable to the vein and
the rib like sections 1002 preferably can be placed in apposition
to the vein wall.
[0277] In one embodiment, the foam is all open celled. In another
embodiment, portions of the foam are open-celled. Open celled foam
allows electrically conductive fluids, such as saline, to flow
through it. The conductive fluid is used as a virtual electrode to
contact the vein wall.
[0278] The foam component preferably has portions that are not
open-celled in order to control or direct the conductive fluid
flow. This is accomplished by using closed-cell foam or giving the
foam surface a skin, which creates a fluid barrier. FIG. 52 shows a
cross section 52-52 of the foam component 1000. The ribs 1002 are
labeled either (+) or (-) to indicate the alternating polarity. As
mentioned above, RF or alternating voltage doesn't have polarity,
but the figures show it in order to help describe the device. The
ribs 1002 preferably have a top edge surface exposed for fluid
flow. The embodiment shown in FIG. 52 is for a bipolar device.
Fluid flow for the (+) polarity and the (-) polarity preferably are
maintained as separate systems electrically to avoid shorting
internal to the device. In another embodiment, FIG. 52 is
monopolar. A single source of conductive fluid is used with a
ground pad on the patient.
[0279] FIGS. 55-56 and 57-58 show embodiments having a braid
component as the working end of the device. These embodiments are
expandable and in some embodiments, each can have a sheath there
over for use placement of the device. FIGS. 57-58 show a
temperature sensor on the braid for temperature control.
[0280] FIGS. 55-56 show the detail of a skived window 1052 on a
section of the braid wire 1050. The wire is electrically connected
and has an insulated jacket on it. The wire insulation can be
polyimide, Teflon.RTM., Pebax.RTM. or other biocompatible
materials, which are stable at the treatment temperatures. Sections
of the insulation are removed to expose the wire on the outer
circumference of the braid. The method to create the skived window
can be mechanical, chemical or by controlled laser or water
cutting.
[0281] This skived window 1052 creates an electrode from the
exposed wire section and places it in contact with the vein wall
only. The window creates a skived electrode similar to the
checkerboard device electrode, however the individual braid wires
1054 are helically wound in the braid pattern and create a diamond
pattern of electrodes. The braid electrode pattern is in apposition
to the vein wall and is conformable before and during
treatment.
[0282] The embodiment 1060 of FIGS. 57-58 utilizes a metal braid
wire 1066 as the working active electrode element. This wire is
round and made of Nitinol.RTM.. However, in other embodiments, the
braid wire may be flat wire and/or comprise an alternate spring
type material as discussed in earlier sections. For this device,
the elastic characteristics of Nitinol.RTM. are beneficial to the
method of expanding and collapsing the device. In one embodiment,
the braid is heat set in the nearly fully expanded position. In
other embodiments, a balloon is used to expand the braid.
[0283] In one embodiment, the braid wire is sleeved in polyimide to
isolate the wires from each other where they overlap as well as to
create the skived electrode. The braid component can be created
using standard braiding technology. Alternatively, a single wire
may be woven into the braid component. The method is relevant for
the overall resistance or impedance of the device for the energy
source.
[0284] The proximal and distal ends of the braid 1066 component are
captured in a two-part crimp sleeve, 1069 and 1071, in order to
anchor the ends to the catheter tube 1070 and stylet 1067. The
braid 1066 in this embodiment is expanded by the use of the
catheter stylet 1067, which runs the internal axial length of the
catheter, from the distal tip 1071 to the proximal handle (not
shown). The proximal end of the stylet passes through a Touhy Borst
type fitting on the catheter handle and in turn is a handle for
stylet manipulation. In this case, pushing the stylet distally
collapses the braid (illustrated in FIG. 57), while pulling the
stylet 1067 expands the braid (illustrated in FIG. 58).
[0285] In the embodiment of the invention illustrated in FIGS.
57-58, a balloon 1068 is placed internal to the braid 1066 such
that the ends are distal to the crimp section 1069 and proximal to
the crimp 1071. As previously discussed, the balloon 1068 is
silicone, but can be other materials previously identified. This
balloon then uses internal lumen and side port (not shown) of the
catheter stylet 1067 for inflation and deflation. The balloon can
also be used to displace blood from lumen being treated to prevent
coagulum build-up on inside of heating element, help direct heat
radially outward to the vein wall and provide a support structure
for the outer heating element ensuring vein wall apposition.
[0286] It should be noted that the typical silicone extrusion may
expand axially and radially when inflated. This causes the balloon
to become "S" shaped for a set axial length of tubing, thus causing
the braid to have non-uniform tissue apposition with the hollow
anatomical structure. To compensate for this issue, the extrusion
1068 may be pre stretched axially just prior to anchoring on the
catheter tubing to the stylet component 1067. The stretched tube
may then expand radially with little to no axial expansion,
depending on the amount of pre-stretch achieved. The balloon may be
used to occlude the vessel to impair blood flow and to remove blood
from the braid portion of the catheter. This creates a static fluid
volume and makes the heat treatment more efficient. Also, the
balloon promotes braid apposition with the hollow anatomical
structure. In other embodiments, the balloon is at least partially
expanded and contracted through expansion and compression of the
ends 1081, 1084.
[0287] In one embodiment, a temperature sensor 1072 is attached to
the braid wire along its axial length. The sensor 1072 may be used
for temperature control during the application of energy for the
controller. Although the sensor 1072 is shown attached near the
proximal end of the braid wire, the sensor 1072 may be located
along other portions of the braid wire. In addition, more than one
sensor may be used.
[0288] In another embodiment, the balloon is a separate device from
the braid device. For example, the balloon device may fit within
the lumen of the braid device, and the tips of both devices may
connect and anchor to one another. For example, the anchor
mechanism may include a set of male and female threads
appropriately sized. Alternatively, the device tips may be anchored
together by use of axially aligned holes in both tips through which
a wire is placed and tied off. Alternatively, the tips may be
designed with a spring ball detent to anchor the tips together.
Alternatively, strong magnets of opposite polarity may be used to
locate the tips and hold them together.
[0289] As discussed above for the fixed diameter electrode element,
the skived electrode wires, when individually wired for power, can
be used in conjunction with the multiplexing process. This allows
the heating of specific active electrode element subsets of the
braid wire set. In one embodiment, at least one braid wire is
energized for a specific dwell time and cascades or moves to the
next braid wire until the end braid wire electrode set is reached.
The cycle is then repeated until the complete treatment time is
reached. The multiplexing can be used for monopolar or bipolar
configurations of braid wire electrode sets. For a monopolar mode,
a ground pad preferably is used in conjunction with active braid
wire electrodes powered by the multiplexer. For a bipolar mode,
adjacent braid wire electrode sets are powered for treatment.
Alternatively, adjacent braid wires can be bipolar so that the
pairs treat the vein along the braid length. Alternatively, one
active braid wire and the two adjacent return braid wires can be
powered to treat the vein wall.
[0290] FIGS. 59 and 60 are a side view and a tip view of one
embodiment 1100 having four expanded splines 1102 with electrodes
1104. One or more splines 1102 can be made of Nitinol.RTM., or
similar matter. The device preferably is configured to place the
ball electrodes 1104 in apposition to a vein wall. One end of the
spline set 1106 preferably is free enabling the electrode set to
adjust and collapse as the treatment shrinks the vein.
[0291] Alternatively, the electrode set can be collapsed to a
smaller diameter by moving the proximal end of the spline set
axially in a proximal direction. A pull wire can be used to move
the proximal end.
[0292] In another embodiment the proximal end is anchored and the
electrode set is collapsed or expanded distally in the axial
direction. A sheath can be used to expand or contract the electrode
set.
[0293] FIGS. 61-64 are additional embodiments using a pre-shaped
Nitinol.RTM. wire for vein conforming. The device 1120 is shown in
several configurations. FIG. 61 shows a sheath 1122 and a wire 1124
in a first low-profile configuration. FIG. 62 shows the wire 1124
in an activated configuration. FIG. 63 is another embodiment 1130,
similar to the embodiments of FIGS. 61, 62, except that the
activated wire 1134 has a different configuration. The wire 1144 of
the embodiment 1140 of FIG. 64 has a double wire configuration.
These configurations are shown as two dimensional forms, however,
the pre-shaped wire can have a three-dimensional or helical shape.
The pre-shaped form can be heat activated or can comprise a shape
memory material. In one embodiment, ball electrodes are placed on
the outer radiuses of the serpentine like curves for vein wall
contact.
[0294] FIG. 65 is another embodiment 1150 using an expandable
balloon-type electrode as the working end of the catheter device
1151. The cylindrical balloon surface 1152 has micro porous holes
1154 in the wall in a defined section. The balloon preferably is
made of a PET (polyethylene terephthalate) or other suitable
material. The balloon wall preferably is placed in apposition to
the vein wall for treatment. In one embodiment, electrically
conductive fluid is used to treat the hollow anatomical structure.
The micropores permit the conductive fluid to contact the inner
wall(s) of the hollow anatomical structure in which the catheter is
deployed. An electrode internal to the balloon uses electrically
conductive fluid, such as saline, to create an electrical path
through the porous balloon surface from fluid ports 1156. The
electrical path continues through the tissue to a ground pad on the
patient when a monopolar system is used. In one embodiment, a
temperature sensor is placed on the balloon surface in the micro
porous section for temperature controlled treatment.
[0295] In some embodiments, the distal portion of the catheter is
collapsible to allow diametrical reduction of the hollow anatomical
structure towards the catheter shaft. As the hollow anatomical
structure is reduced, the distal catheter portion moves with
respect to the catheter shaft in a radially collapsing direction.
This movement preferably is monitored and/or conveyed to the handle
to signal the end of treatment. In some embodiments, a pre-set
axial migration of the distal portion is correlated to a specific
lumenal reduction.
[0296] Except as further described herein, any of the catheters
and/or devices or components of these catheters or devices
disclosed in FIGS. 30-65 may, in some embodiments, be similar to
any of the catheters described in U.S. Pat. No. 6,401,719, issued
Jun. 11, 2002, titled METHOD OF LIGATING HOLLOW ANATOMICAL
STRUCTURES; or in U.S. Pat. No. 6,179,832, issued Jan. 30, 2001,
titled EXPANDABLE CATHETER HAVING TWO SETS OF ELECTRODES; or in
FIGS. 1-26 herein; or in U.S. Provisional Patent Application No.
60/613,415, filed Sep. 27, 2004, titled RESISTIVE ELEMENT SYSTEM.
In addition, any of the catheters and/or devices or components of
these catheters or devices disclosed herein may, in certain
embodiments, be employed in practicing any of the methods disclosed
in the above-mentioned U.S. Pat. Nos. 6,401,719 or 6,179,832, or in
FIGS. 1-26 herein, or in the above-mentioned Provisional
Application No. 60/613,415. The above-mentioned U.S. Pat. Nos.
6,401,719 and 6,179,832 and Provisional Application No. 60/613,415
are hereby incorporated by reference herein and made a part of this
specification.
[0297] Shown in FIG. 66 is a catheter for applying energy to a
hollow anatomical structure (HAS). The catheter includes a catheter
shaft 1210, a sheath 1216, a sensor 1211, a tip 1215 and a handle
1214. The handle has an open port 1212 for fluid infusion and/or
guidewire introduction, and a connection 1213 for interfacing with
an energy source 1218.
[0298] The catheter shaft 1210 can be comprised of a biocompatible
material preferably having a low coefficient of friction, such as
polyimide, Teflon.RTM., Hytrel.RTM. or other suitable material. The
catheter shaft can be sized to fit within a hollow anatomical
structure (HAS) between 6 and 8 French, which corresponds to a
diameter of between 2.0 mm (0.08 in) and 2.7 mm (0.10 in), or other
sizes as appropriate. The catheter shaft 1210 is used to maneuver
the distal portion of the catheter during placement.
[0299] The retractable sheath 1216 exposes the distal portion of
the device that applies energy to the HAS. The sheath can be
employed to protect the device during placement, facilitate
introduction of the device and/or adjust the exposed axial length
for a desired treatment length. The sheath can be made from a
biocompatible material preferably having a low coefficient of
friction, such as polyimide, Teflon.RTM., Hytrel.RTM. or other
suitable material.
[0300] The distal portion of the device transfers electrical energy
to the HAS for treatment. This portion may have a heating element
that directly heats the HAS through heat conduction from the
catheter shaft to the wall tissue. This portion may also
incorporate a set of electrodes that deliver RF energy to the HAS
and thereby generate heat within the HAS. This energy can be
delivered up to a predetermined temperature or power level.
[0301] An atraumatic tip 1215 can be attached to the distal-most
catheter end. The tip facilitates manipulation of the catheter
through the HAS. The tip is preferably tapered inward at its distal
end or is "nosecone" shaped, however, it can have other shapes that
facilitate tracking of the catheter over a guide wire and through
the bends and ostia in the vascular system. The nosecone-shaped tip
can, for example, be fabricated from a polymer having a soft
durometer. In some embodiments, the tip can be fabricated from
polymers having durometers between about 60 and about 90 Shore A.
In other embodiments, the tip can be fabricated from polymers with
durometers between about 70 and about 80 Shore A, and in one
preferred embodiment, a material with a durometer of about 70 Shore
A is used.
[0302] A sensor 1211 can be attached to the exterior of the distal
catheter shaft; this sensor can sense values pertinent to measuring
the treatment's progress, such as temperature, impedance, or other
pertinent treatment parameters. A single sensor 1211 is shown as
part of the heating element; there can also be multiple sensors
placed along the axial catheter length. The parameter measured will
typically be that of the HAS tissue itself. The energy system 1218
can be employed to monitor the individual sensors and use the
multiple inputs for feedback. The controller can be employed to
monitor for high or low signals, and the microprocessor can be
employed to determine the energy output accordingly. This control
feedback mechanism may facilitate a more appropriate amount of
energy to effectively and safely treat the HAS.
[0303] The handle houses an open port 1212 that directly
communicates with an inner lumen extending the entire catheter
length. FIG. 67 depicts the inner lumen 1217 contained within the
catheter shaft 1210 that communicates with the handle open port
1212. The catheter can be periodically flushed with saline through
the port; flushing prevents the buildup of biological fluid, such
as blood, within the catheter shaft.
[0304] The treatment area of the HAS can also be flushed with a
fluid such as saline through the inner lumen 1217 in order to
evacuate blood from the treatment area of the HAS so as to prevent
the formation of coagulum and subsequent thrombosis.
[0305] When the energy delivery method is an RF-based system, the
use of a dielectric fluid (e.g., disposed within or around the HAS)
can minimize unintended heating effects away from the treatment
area. The dielectric fluid prevents the current of RF energy from
flowing away from the HAS, instead it concentrates the energy
delivered to the intended target. Any suitable dielectric fluid can
be used as desired, for example dextrose is often used as a
dielectric fluid in medical treatment contexts.
[0306] Alternative endolumenal implementations of fluid that can be
delivered through the inner lumen 1217 might include drug therapies
that promote fibrotic growth post endothelial layer destruction,
such as TGF (Transforming Growth Factor) which is widely known to
promote fibrotic reactions.
[0307] The inner lumen 1217 may also allow for the delivery of
sclerosants to the interior of the HAS through an outlet at or near
the distal end. Sclerosants typically denude the endothelial layer
to damage and scar the inner HAS and further facilitate treatment
of the HAS together with electrical energy delivery. Sclerosants,
such as Polidocanol, hypertonic saline and Sclerodex or other
chemical solutions with appropriate toxicity to endothelial cells
are widely known in the art.
[0308] Finally, a guidewire can also be introduced through the
inner lumen 1217 to facilitate catheter navigation to the desired
treatment site. The guidewire is advanced to the treatment site
prior to catheter advancement; once in place, the catheter is
advanced over the guidewire to the treatment site.
[0309] The handle 1214 also houses an electrical connection that
connects the energy system 1218 to a single or plurality of leads
traveling down the catheter shaft. These leads may transfer direct
thermal heat, or they may be switched as desired to operate in
either a bipolar or a monopolar RF-based configuration. The number
of leads can be dependent on the size or diameter of the HAS to be
treated; larger vessels may require more leads to ensure proper
current density and/or heat distribution. FIG. 68 shows the energy
system 1218 is made up of an energy source 1223, a microprocessor
1219, a controller 1220, a feedback mechanism 1221 and a visual
output 1222.
[0310] The energy source 1223 is typically an AC (alternating
current) power supply like an RF generator, or a DC (direct
current) power supply. The DC power source may also be disposable
in form such as a battery. Alternate energy sources may also
comprise a laser, microwave, ultrasound, high-intensity ultrasound
or other source.
[0311] The controller 1220, receives data from the feedback
mechanism 1221 and modifies the energy delivery accordingly. The
feedback mechanism may receive data from the sensor 1211, for
example, and the controller may modify the energy source to supply
heat to the HAS at a pre-set parameter. In an alternate embodiment,
the user can select a constant power output; the user can then
manually adjust the power output relative to the visual output 1222
from the sensor 1211 located at the working portion of the
catheter.
[0312] The microprocessor 1219 works in conjunction with the
controller to provide the algorithm by which the feedback data is
processed.
[0313] The visual output 1222 can be employed to provide visual
verification of critical values obtained during treatment of the
HAS.
[0314] FIG. 69 shows a first embodiment of the catheter design with
a distal portion 1209 that transfers the energy directly to the HAS
when expanded. In this configuration, the distal portion is
pre-formed into a planar serpentine shape that stretches the
opposing walls of the HAS outward until the top & bottom are
forced together and collapsed onto the distal portion. In this
expanded shape, the device can be at, for example, a minimum planar
thickness range of 2 Fr to 10 Fr (0.66 mm to 3.3 mm) and maximum
width range of 3 mm to 25 mm. The intent is to expand and flatten
the HAS to approximately the thickness or diameter of the catheter
distal portion. An example of a serpentine section is a device
distal portion which is 4 Fr or 1.33 mm in diameter with a possible
expansion width of 20 mm. A specific example would be to place a 5
Fr or 1.67 mm diameter device in a 8 mm diameter vein. The device
then expands and in turn decreases the top to bottom height of the
HAS from 8 mm down to 1.67 mm or about a 380% reduction. This would
also push the side wall portions of the HAS out to a maximum of
about 10-12 mm width. If the HAS is smaller, naturally the
percentage reduction will be less and vise versa.
[0315] FIG. 70 shows the distal portion of the catheter shaft
retracted within the sheath 1216. Once within the sheath, the
pre-formed curve of the distal portion is overcome by the column
strength and radial strength of the sheath. In this retracted or
compressed state, the catheter is at full length and minimum width
(diameter) and can be introduced into the HAS prior to treatment as
well as be removed from the HAS after treatment has been
completed.
[0316] FIGS. 71 and 72 show cross sectional detail portions of a
version of the distal portion 1209, shown in FIG. 69. FIG. 71 shows
a sectional view of the distal portion of the sheath. The main tube
lumen 1270 is lined with a low friction material 1271 such as
Teflon FEP. This liner lets the deformable distal portion 1209 of
the device to retract and compress or release and expand with
reasonable handling forces. The distal portion 1209 of the device
may also have a low friction surface 1277 as well as using similar
materials as the outer surface. The internal liner 1272 may be of
the same material as the low friction material 1271 or comprise a
different material. FIG. 72 shows a cross section of the distal
portion 1209 of the device. The main stiffener component 1275 of
the device shapes the distal section and is made of materials such
as (but not limited to) Nitinol or similar nickel based spring
alloys, other spring alloys, 17-7 stainless, Carpenter 455 type
stainless, beryllium copper, or shape-memory materials. The intent
of the stiffener is to physically conform the HAS to a
substantially planar shape, yet be flexible enough to collapse into
the device sheath with reasonable handling forces. The cross
section of component 1275 could be round, rectangular, or some
other shape. Flat or rectangular wire when used for component gives
flexibility for conformability and good planar stiffness when
expanded. The heating element 1276 is placed on the electrically
insulated stiffener 1275 and covered by an insulated outer sleeve
1273, which can be made of a material such as Teflon or FEP.
[0317] Alternatively, a softer distal tube section could be used
which would be more flexible. In this configuration shown in FIG.
73, the coil heating element is on the outer surface of this tube
and has gaps between the coils for flexibility of the distal tube.
A pre shaped Nitinol wire 1275 resides within the internal lumen of
1273. The proximal end of the shaped wire is anchored to the
proximal handle 1214 as a slidable knob while the distal end of the
same wire is attached the tip of the catheter tube by a blunt tip
1274. The hypo-tube 1270, acting similar to a sheath, can be
coaxial to the Nitinol wire 1275 and catheter tube 1273. The
hypo-tube 1270 is moveable distally along the shaped wire. This
hypo-tube component 1270 is actuated from the proximal handle end.
The hypo-tube can be the length of the catheter or use a stylet
type wire connected between it and the handle mechanism. Similar to
the embodiment of FIG. 69, the hypo tube can slide over the
stationary shaped wire to straighten it. As previously mentioned in
the collapsed form the catheter can be used for initial placement,
adjustment or removal from the HAS.
[0318] FIG. 74 shows a second embodiment of the design in which the
distal portion 1209 can be formed by actuation of a
distally-anchored wire, which may be pushed or pulled. The distal
portion 1209 can be formed with a slight curve bias to achieve this
shape when actuated at the handle.
[0319] FIG. 75 shows a cross-sectional view of the catheter shaft
1210 within the sheath 1216. The actuation wire 1232 is housed
within a dedicated actuation wire lumen 1230 which extends to the
distal portion of the device. At the point in which the formed
distal portion 1209 begins, the actuation wire 1232 is then
suspended on the distal catheter shaft via evenly spaced-apart
rings 1231. In this expanded shape, the device is preferably at
minimum length and maximum width.
[0320] FIG. 76 shows an alternate version of the catheter distal
tube portion 1209. The distal tube is free from anchors to create
the planar predefined curved shape. The stylet wire is hinged to
the tip 1274, so that the distal tip is free to adjust based upon
the actuation of the stylet wire. In this configuration the
actuation wire 1232 is stiff and controls the pre-shape wire
length. By moving the actuation wire proximally, the straight
distal section shown in FIG. 76 becomes one of the versions shown
to the right of FIG. 76. Moving the actuation wire 1232 proximally
will straighten the curved distal portion out. As shown on the
right side of FIG. 76, one or two pre-formed curve distal sections
can be used in various shapes to get increased contact to the
HAS.
[0321] In another embodiment shown in FIG. 77, the planar multiple
curve shape is defined by the cut pattern in a hypo-tube component.
The cut pattern will determine the shape and the amount of
curvature possible, and, as illustrated, various cut patterns may
be used. The hypo-tube wall thickness and the depth of cut can
affect the stiffness and flexibility of the curve as well. The
shape that the cut hypo-tube component may assume can be any shape
that will facilitate the purposes of conforming the HAS to the
device. For example, the component may assume a helical shape or a
serpentine shape, as illustrated in FIG. 77A. The cut hypo-tube
could utilize the pull wire 1230 as shown in FIG. 74 for conformal
shaping or alternatively the cut hypo-tube could be shape set by
using materials such as Nitinol or a spring alloy which can be heat
set for shape. By use of an outer sheath, the shape set distal
portion would be expanded or collapsed like the device in FIG.
69.
[0322] FIG. 78 shows a third embodiment of the catheter in its
expanded state, or the state at which the catheter is ready to
transfer energy to the HAS. The distal portion is comprised of a
plurality of rings 1241 slidably disposed on the catheter shaft
1210. Typically, at least one of the rings 1241 is fixed relative
to the catheter shaft so that one or both of the remaining rings
can be slid towards or away from the fixed ring(s). Attached to the
rings 1241 are two ribbon-like elements 40 that transfer energy to
the HAS. The ribbon elements can have a cross-section that
facilitates the desired outward planar expansion--such as
rectangular, elliptical, etc.--when actuated. The ring/ribbon array
can be attached to the catheter shaft at its distal end allowing
outward planar movement when an actuation rod (not shown), attached
to the proximal end of the ring/ribbon array, is actuated.
[0323] The ribbon elements 1240 can be made of an
electrically-resistive material, such as nickel chromium, copper,
stainless-steel, Nitinol.RTM., Alumel.RTM. or other suitable
materials, that heat when an energy source is applied. This mode of
energy transfer would be direct heat conduction to the HAS tissue.
The relative resistance or impedance of the resistive element is
designed to be optimized for the energy source 1223. The resistive
element will depend on the catheter diameter, the energy required,
and the energy source requirements.
[0324] The ribbon elements 1240 and catheter shaft 1210 can also be
used as electrodes to facilitate an RF-based treatment. In this
embodiment, the ribbon elements 1240 would be made of a conductive
material, such as those already discussed in the previous
paragraph. In one scenario, the ribbon elements 1240 could be
positively charged, and the catheter shaft could be negatively
charged. In a second scenario, one of the ribbon elements could be
positively charged, and the other ribbon element could be
negatively charged. In a third scenario, both ribbon elements and
the catheter shaft could both be positively charged to facilitate a
monopolar RF-based treatment.
[0325] FIG. 79 shows the same embodiment in its "compressed" state,
or the state prior to treatment in which the catheter is introduced
into or removed from the HAS. In the arrangement, the actuation rod
(not shown) has been moved with respect to the distal catheter tip
to facilitate collapse of the ribbon elements. The sheath 1216 can
then be advanced towards the distal tip to protect the ring/ribbon
array.
[0326] An alternate embodiment is shown in FIG. 80. The ribbon
elements 1240 of FIG. 78 and 79 are replaced by a compressible coil
like spring 1240' made of resistant material as previously
discussed. The coil spring has anchor points 1241' which attach and
slide axially to the central catheter shaft. The actuation rod is
internal to the catheter shaft and is not shown. As the actuation
rod is moved proximally relative to the catheter main body, the
coil spring 1240' elongates as it too moved proximal and becomes
linear or straight, as shown in FIG. 79. When the actuation rod is
moved distally, the coil spring is expanded in width to form the
curves.
[0327] In another embodiment, as shown in FIG. 83, a device uses
two expandable bow like splines 1240 to reshape and conform the HAS
to the device shape. FIG. 83 shows the device collapsed and inside
a vein. This device configuration is used for placement or removal
from the HAS. FIG. 85 shows the device expanded in the vessel 1250.
The planar shape of the vessel 1250 is evident in FIG. 85. In FIG.
86, the broken lines 1240 represent the expanded splines which are
in contact with the vein wall, which is shown to be wider than the
adjacent sections of this vein 1250. The actuation is accomplished
by anchoring the distal portion of each spline 1240 to the catheter
tip section. The proximal portion of the spline is attached to an
internal stylet wire, not shown, which extends to the proximal end
of the catheter. This stylet wire is moveable at the handle 1214
such that it can expand or collapse the splines at the distal
tip.
[0328] FIGS. 87-88 show the collapsed device in the vein as
previously discussed in connection with FIG. 83. In this alternate
embodiment the splines are contained within an elastic film or
extrusion made of a material such as silicone. FIGS. 88 and 90 show
the elastic film as a gradient shaded section. By expanding the
splines, the silicone tube is stretched to a similar cross section
as the vein wall in FIG. 85. By encapsulating the splines and
catheter tube, the build up of coagulum is greatly reduced and will
increase the uniformity of heating.
[0329] Shown in FIGS. 91 and 92 are cross-sectional views of the
HAS 1250 and distal portion of the catheter shaft 1210 before (FIG.
91) and after (FIG. 92) device deployment. Once actuated, the
distal portion of the catheter expands outward in a planar fashion
to conform the HAS shape to that of the device. This facilitates
direct contact of the HAS with the heating elements of the
device.
[0330] To ensure even more complete HAS contact, other means to
facilitate HAS wall contact may be applied in the form of tumescent
infiltration, exterior manual compression, Trendelenburg
positioning, and/or the use of veno-constrictive agents. For
example, FIGS. 93-95 show cross-sections of a device's catheter
shaft 1210 within a vein 1250 that is within a perivenous
compartment 1260. This compartment 1260 is made up of a superficial
& deep fascial layers encapsulating the vein and providing a
finite three-dimensional space. FIG. 93 shows partial vein wall
conformance to the deployed device within fascial layers that are
generally non-uniform and unstructured in nature. FIG. 94 shows
improved vein wall conformance to the deployed device due to the
infiltration of tumescent 1261. Because the perivenous compartment
1260 provides essentially a fixed external envelope, the
infiltrated tumescent forces the vein wall further towards the
endovenously-placed device. The tumescent essentially provides a
circumferentially uniform compressive force inward to the HAS. In
FIG. 95, exterior manual compression 1262 is applied from the
surface downward onto the perivenous compartment. This provides a
non-uniform force causing further perivenous compartment
deformation which leads to improved device apposition to the HAS
walls. In doing so, more complete vein wall conformance to the
deployed device can be achieved. Although FIG. 93 represents an
improvement in the art such that device-to-HAS apposition is
greatly increased allowing for more effective energy delivery to
the HAS, additional compression provided by ancillary methods
embodied in FIGS. 93 and 94 might be employed but are not
required.
[0331] In any of the device embodiments already discussed, the
distal portion of the catheter may be collapsible in nature to
allow lumenal reduction of the HAS towards the catheter shaft
during energy application. As this lumenal reduction occurs, the
distal end may move axially, in the proximal direction. Since
reduction in HAS diameter typically signals successful application
of energy, this axial movement could be monitored and/or conveyed
to the handle signaling the end of treatment. In other words, a
pre-set axial migration of the distal device portion could be
correlated to a specific lumenal reduction. A signal capturing this
movement could also be conveyed directly to the energy system as a
feedback mechanism to the microprocessor to signal end of treatment
to the energy source. The energy source could then stop delivering
energy and the visual output could indicate successful and/or
treatment end.
[0332] In one embodiment, a distal end of an HAS conforming device
can be made of a shape-memory material, such as a nickel-titanium
alloy. Such a device can be shape set and heat treated such that
the device assumes a contracted shape when the material is below a
pre-determined transition temperature, and assumes an expanded
shape when the material is raised above the transition temperature.
In some embodiments, the material can be selected and treated such
that the transition temperature is above a patient's normal body
temperature, but below an operating temperature of the device. In
the case of a resistance-heated device, the temperature of the
distal section can be controlled directly.
[0333] The first step in facilitating complete vein wall
conformance is to introduce the device to the HAS. Once the device
is placed in the desired location within the HAS, the device is
deployed causing HAS conformance. If applicable and practical, the
external compartment is then infiltrated with tumescent agent(s),
and externally-placed manual compression is applied directly down
onto the HAS. These steps help to promote a more effective
treatment by removing HAS conformance inconsistencies due to vessel
variability. Likewise, the additional measures of veno-constrictive
agents and/or Trendelenburg positioning may be used.
[0334] Except as further described herein, any of the catheters
disclosed in FIGS. 66-95 herein may, in some embodiments, be
similar to any of the catheters described in U.S. Pat. No.
6,401,719, issued Jun. 11, 2002, titled METHOD OF LIGATING HOLLOW
ANATOMICAL STRUCTURES; or in U.S. Pat. No. 6,179,832, issued Jan.
30, 2001, titled EXPANDABLE CATHETER HAVING TWO SETS OF ELECTRODES;
or in FIGS. 1-26 or 36-65 herein; or in U.S. Provisional Patent
Application No. 60/613,415, filed Sep. 27, 2004, titled RESISTIVE
ELEMENT SYSTEM; or in U.S. Provisional Patent Application No.
60/621,251, filed Oct. 22, 2004, titled VEIN CONFORMING CATHETER.
In addition, any of the catheters disclosed in FIGS. 66-95 herein
may, in certain embodiments, be employed in practicing any of the
methods disclosed in the above-mentioned U.S. Pat. Nos. 6,401,719
or 6,179,832, or the above-mentioned Provisional Applications No.
60/613,415 or 60/621,251. The above-mentioned U.S. Pat. Nos.
6,401,719 and 6,179,832 and Provisional Applications Nos.
60/613,415 and 60/621,251 are hereby incorporated by reference
herein and made a part of this specification.
[0335] Although invention(s) have been disclosed in the context of
certain preferred embodiments and examples, it will be understood
by those skilled in the art that the invention(s) extend beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses of the invention(s) and obvious modifications and
equivalents thereof. Thus, it is intended that the scope of the
disclosed invention(s) should not be limited by the particular
embodiments described above, but should be determined only by a
fair reading of the claims that follow.
* * * * *