U.S. patent application number 12/026461 was filed with the patent office on 2008-09-18 for angioplasty balloon with concealed wires.
This patent application is currently assigned to Cook Incorporated. Invention is credited to Kevin Leffel, Jeffry S. Melsheimer.
Application Number | 20080228139 12/026461 |
Document ID | / |
Family ID | 39763425 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080228139 |
Kind Code |
A1 |
Melsheimer; Jeffry S. ; et
al. |
September 18, 2008 |
Angioplasty Balloon With Concealed Wires
Abstract
A balloon catheter having wires situated between an outer layer
and a surface of a balloon is described. Each wire may be confined
within an interior space of a pocket or encapsulated within a
sheath. The pocket includes the outer layer and the balloon
surface. The outer layer and balloon surface are unattached to
allow the wire to slidably fit between therewithin. The pocket is
selectively bonded to the balloon. The sheath includes a preformed
shape that completely circumscribes the wire along the longitudinal
and radial directions of the wire. The confined and encapsulated
feature of the wires enable the wires to be atraumatic and remain
spaced apart during treatment of calcification of a lesion.
Inventors: |
Melsheimer; Jeffry S.;
(Springville, IN) ; Leffel; Kevin; (Bloomington,
IN) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE/CHICAGO/COOK
PO BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Cook Incorporated
Bloomington
IN
|
Family ID: |
39763425 |
Appl. No.: |
12/026461 |
Filed: |
February 5, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60899802 |
Feb 6, 2007 |
|
|
|
Current U.S.
Class: |
604/103.08 |
Current CPC
Class: |
A61M 25/104 20130101;
A61M 2025/1086 20130101 |
Class at
Publication: |
604/103.08 |
International
Class: |
A61M 25/10 20060101
A61M025/10 |
Claims
1. A balloon catheter for dilation of a body lumen, comprising: a
shaft having a distal end and a proximal end; a balloon mounted on
the distal end of the shaft, the balloon having a distal portion
and a proximal portion, the shaft having an inflation lumen
extending therethrough in fluid communication with an interior
region of the balloon, the balloon thereby being expandable between
a deflated state and an inflated state; and a wire extending along
an outer surface of the balloon, the wire disposed between the
outer surface of the balloon and an outer layer, the outer layer at
least partially circumscribing the wire along a longitudinal length
of the wire, the outer layer having an axial length, the outer
layer being attached to the outer surface of the balloon at one or
more locations.
2. The balloon catheter of claim 1, wherein the outer layer is
unattached to the outer surface of the balloon at one or more
regions, thereby forming a pocket between the outer layer and the
outer surface of the balloon, and the wire being disposed within
the pocket.
3. The balloon catheter of claim 2, wherein the pocket is
longitudinally aligned with a longitudinal axis of the balloon, the
pocket comprising a first opening adapted to slidably receive a
wire.
4. The balloon catheter of claim 3, the pocket further comprising a
seam to define the edges of the pocket.
5. The balloon catheter of claim 2, wherein a retaining element is
affixed to the wire to maintain the wire in the pocket.
6. The balloon catheter of claim 3, wherein the first opening is
sealed to enclose the wire within the pocket.
7. The balloon catheter of claim 2, wherein the wire is not bonded
to interior surfaces of the pocket.
8. The balloon catheter of claim 1, wherein the outer layer is a
sheath encapsulating the wire, the sheath completely circumscribing
the wire along a longitudinal length of the wire.
9. A balloon catheter for dilation of a body lumen, comprising: a
shaft having a distal end and a proximal end; a balloon mounted on
the distal end of the shaft, the shaft having an inflation lumen
extending therethrough in fluid communication with an interior
region of the balloon, the balloon thereby being expandable between
a deflated state and an inflated state, wherein at least a length
of an outer surface of the balloon comprises a working diameter
adapted to dilate the body lumen, the length extending between a
balloon proximal end and a balloon distal end; a pocket disposed
along at least a portion of the outer surface of the balloon, the
pocket comprising an interior space defined by portions of an outer
layer selectively unattached to the outer surface, the pocket
further comprising a seam defined by portions of the outer layer
attached to the outer surface of the balloon, the outer layer
disposed over the outer surface of the balloon and extending along
a portion of the working diameter of the balloon; a wire disposed
within the interior space defined by the pocket; and a retaining
element affixed to the wire, the retaining element preventing the
wire from sliding out of the pocket.
10. The balloon catheter of claim 9, wherein the seam comprises an
undulating shape.
11. The balloon catheter of claim 9, wherein the attachment of the
outer layer to the outer surface of the balloon at the one or more
locations comprises heat bonding, solvent bonding, or adhesive
bonding the outer layer to the outer surface.
12. The balloon catheter of claim 9, wherein the catheter comprises
a plurality of pockets.
13. The balloon catheter of claim 12, wherein the plurality of
pockets are longitudinally aligned with a longitudinal axis of the
balloon, the plurality of pockets being circumferentially
equidistant from each other.
14. A balloon catheter for dilation of a body lumen, comprising: a
shaft having a distal end and a proximal end; a balloon mounted on
the distal end of the shaft, the shaft having an inflation lumen
extending therethrough in fluid communication with an interior
region of the balloon, the balloon thereby being expandable between
a deflated state and an inflated state, wherein at least a length
of an outer surface of the balloon comprises a working diameter
adapted to dilate the body lumen, the length extending between a
balloon proximal end and a balloon distal end; and a wire
comprising an axial length, the wire encapsulated by a sheath
disposed along a portion of the working diameter of the balloon,
the sheath being disposed over an outer surface of the balloon.
15. The balloon catheter of claim 14, wherein the sheath has a
tubular shape, the sheath fusion bonded to the outer surface of the
balloon.
16. The balloon catheter of claim 14, the sheath being movable
between a first position and a second position, wherein the first
position comprises a resting state where the balloon is deflated
and the second position comprises a stretched state where the
balloon is inflated.
17. The balloon catheter of claim 14, wherein the wire comprises a
non-adhesive coating to minimize bonding with the sheath.
18. The balloon catheter of claim 14, wherein the sheath comprises
a cutting edge.
19. The balloon catheter of claim 14, wherein the wire has a
proximal end and a distal end, the sheath axially extending past
the proximal and the distal ends.
20. The balloon catheter of claim 14, wherein the sheath
circumscribes the wire along the entire axial length of the wire.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of priority from U.S.
Provisional Application No. 60/899,802 filed Feb. 6, 2007, which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates generally to medical devices
and more particularly to balloon catheters used to dilate narrowed
portions of a lumen.
BACKGROUND
[0003] Balloon catheters are widely used in the medical profession
for various intraluminal procedures. One common procedure involving
the use of a balloon catheter relates to angioplasty dilation of
coronary or other arteries suffering from stenosis (i.e., a
narrowing of the arterial lumen that restricts blood flow).
[0004] Although balloon catheters are used in many other procedures
as well, coronary angioplasty using a balloon catheter has drawn
particular attention from the medical community because of the
growing number of people suffering from heart problems associated
with stenosis. This has lead to an increased demand for medical
procedures to treat such problems. The widespread frequency of
heart problems may be due to a number of societal changes,
including the tendency of people to exercise less while eating
greater quantities of unhealthy foods, in conjunction with the fact
that people generally now have longer life spans than previous
generations. Angioplasty procedures have become a popular
alternative for treating coronary stenosis because angioplasty
procedures are considerably less invasive than other alternatives.
For example, stenosis of the coronary arteries has traditionally
been treated with bypass surgery. In general, bypass surgery
involves splitting the chest bone to open the chest cavity and
grafting a replacement vessel onto the heart to bypass the blocked,
or stenosed, artery. However, coronary bypass surgery is a very
invasive procedure that is risky and requires a long recovery time
for the patient.
[0005] To address the increased need for coronary artery
treatments, the medical community has turned to angioplasty
procedures, in combination with stenting procedures, to avoid the
problems associated with traditional bypass surgery. Typically,
angioplasty procedures are performed using a balloon-tipped
catheter that may or may not have a stent mounted on the balloon
(also referred to as a stented catheter). The physician performs
the angioplasty procedure by introducing the balloon catheter into
a peripheral artery (commonly one of the leg arteries) and
threading the catheter to the narrowed part of the coronary artery
to be treated. During this stage, the balloon is uninflated and
collapsed onto the shaft of the catheter in order to present a low
profile which may be passed through the arterial lumens. Once the
balloon is positioned at the narrowed part of the artery, the
balloon is expanded by pumping a mixture of saline and contrast
solution through the catheter to the balloon. As a result, the
balloon presses against the inner wall of the artery to dilate it.
If a stent is mounted on the balloon, the balloon inflation also
serves to expand the stent and implant it within the artery. After
the artery is dilated, the balloon is deflated so that it once
again collapses onto the shaft of the catheter. The balloon-tipped
catheter is then retracted from the arteries. If a stent is mounted
on the balloon of the catheter, the stent is left permanently
implanted in its expanded state at the desired location in the
artery to provide a support structure that prevents the artery from
collapsing back to its pre-dilated condition. On the other hand, if
the balloon catheter is not adapted for delivery of a stent, either
a balloon-expandable stent or a self-expandable stent may be
implanted in the dilated region in a follow-up procedure. Although
the treatment of stenosed coronary arteries is one common example
where balloon catheters have been used, this is only one example of
how balloon catheters may be used and many other uses are also
possible.
[0006] One problem that may be encountered with conventional
angioplasty techniques is the proper dilation of stenosed regions
that are hardened and/or have become calcified. Stenosed regions
may become hardened for a variety of reasons, such as the buildup
of atherosclerotic plaque or other substances. Hardened regions of
stenosis can be difficult to completely dilate using conventional
balloons because hardened regions tend to resist the expansion
pressures applied by conventional balloon catheters. Although the
inventions described below may be useful in treating hardened
regions of a stenosis, the claimed inventions may also solve other
problems as well.
SUMMARY
[0007] Accordingly, a balloon catheter is provided in which a wire
is situated within a pocket or a sheath.
[0008] The invention may include any of the following aspects in
various combinations and may also include any other aspect
described below in the written description or in the attached
drawings.
[0009] A balloon catheter for dilation of a body lumen, comprising:
a shaft having a distal end and a proximal end; a balloon mounted
on the distal end of the shaft, the balloon having a distal portion
and a proximal portion, the shaft having an inflation lumen
extending therethrough in fluid communication with an interior
region of the balloon, the balloon thereby being expandable between
a deflated state and an inflated state; and a wire extending along
an outer surface of the balloon, the wire disposed between the
outer surface of the balloon and an outer layer, the outer layer at
least partially circumscribing the wire along a longitudinal length
of the wire, the outer layer having an axial length, the outer
layer being attached to the outer surface of the balloon at one or
more locations.
[0010] The balloon catheter, wherein the outer layer is unattached
to the outer surface of the balloon at one or more predetermined
regions, the unattachment forming a pocket between the outer layer
and the outer surface of the balloon for the wire to be disposed
therewithin.
[0011] The balloon catheter, wherein the pocket is longitudinally
aligned with a longitudinal axis of the balloon, the pocket
comprising a first opening adapted to slidably receive a wire.
[0012] The balloon catheter, the pocket further comprising a seam
to define the edges of the pocket.
[0013] The balloon catheter, wherein a retaining element is affixed
to the wire to maintain the wire in the pockets.
[0014] The balloon catheter, wherein the first end is sealed to
enclose the wire within the pocket.
[0015] The balloon catheter, wherein the wire is not bonded to
interior surfaces of the pocket.
[0016] The balloon catheter, wherein the outer layer encapsulates
the wire, the outer layer completely circumscribing the wire along
the longitudinal length of the wire.
[0017] The balloon catheter, wherein the outer layer is a polymeric
sheath.
[0018] A balloon catheter for dilation of a body lumen, comprising:
a shaft having a distal end and a proximal end; a balloon mounted
on the distal end of the shaft, the shaft having an inflation lumen
extending therethrough in fluid communication with an interior
region of the balloon, the balloon thereby being expandable between
a deflated state and an inflated state, wherein at least a length
of an outer surface of the balloon comprises a working diameter
adapted to dilate the body lumen, the length extending between a
balloon proximal end and a balloon distal end; a pocket situated
along the outer surface of the balloon, the pocket comprising an
interior space defined by portions of an outer layer selectively
unattached to the outer surface, the pocket further comprising a
seam defined by portions of the outer layer attached to the outer
surface of the balloon, the outer layer disposed over the outer
surface of the balloon and extending along the working diameter of
the balloon; a wire residing within the pocket; and a retaining
element affixed to the wire, the retaining element preventing the
wire from sliding out of the pocket.
[0019] The balloon catheter, the seam comprising an undulating
shape.
[0020] The balloon catheter, wherein the attachment of the outer
layer to the outer surface of the balloon at the one or more
locations comprises bonding the outer layer to the outer
surface.
[0021] The balloon catheter, wherein the bonding comprises heat
bonding, solvent bonding, or adhesive bonding.
[0022] The balloon catheter, wherein the catheter comprises a
plurality of pockets.
[0023] The balloon catheter, wherein the plurality of pockets are
longitudinally aligned with a longitudinal axis of the balloon, the
plurality of pockets being circumferentially equidistant from each
other.
[0024] A balloon catheter for dilation of a body lumen, comprising:
a shaft having a distal end and a proximal end; a balloon mounted
on the distal end of the shaft, the shaft having an inflation lumen
extending therethrough in fluid communication with an interior
region of the balloon, the balloon thereby being expandable between
a deflated state and an inflated state, wherein at least a length
of an outer surface of the balloon comprises a working diameter
adapted to dilate the body lumen, the length extending between a
balloon proximal end and a balloon distal end; and a wire
comprising an axial length, the wire encapsulated by a sheath
situated along the working diameter of the balloon, the sheath
circumscribing the wire along the entire axial length of the wire,
the sheath disposed over an outer surface of the balloon
[0025] The balloon catheter, the sheath having a tubular shape, the
sheath fusion bonded to the outer surface of the balloon.
[0026] The balloon catheter, the sheath movable between a first
position and a second position, wherein the first position
comprises a resting state where the balloon is deflated and the
second position comprises a stretched state where the balloon is
inflated.
[0027] The balloon catheter, the wire comprising a non-adhesive
coating to minimize bonding with the sheath.
[0028] The balloon catheter, the sheath comprising a cutting
edge.
[0029] The balloon catheter, the wire having a proximal end and a
distal end, the sheath axially extending past the proximal and the
distal ends.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Embodiments will now be described by way of example with
reference to the accompanying drawings, in which:
[0031] FIG. 1 is a perspective view of a balloon catheter with
wires disposed within pockets;
[0032] FIGS. 2a-2c are cross-sectional views of balloon catheters
with wires disposed within pockets of various geometries;
[0033] FIG. 3 is perspective view of a balloon catheter having an
outer layer in the form of a sheet wrapped around the outer surface
of the balloon;
[0034] FIG. 4 is a perspective view of a balloon catheter having an
outer sleeve disposed about a balloon;
[0035] FIG. 5 is a perspective view of an outer balloon portion
slid over an underlying balloon;
[0036] FIG. 6 is a perspective view of an outer layer bonded to a
balloon to form pockets; and
[0037] FIG. 7 is a perspective view of a mechanical mask disposed
over the balloon as the outer layer is bonded to the balloon;
[0038] FIGS. 8a-8c are cross-sectional views of balloon catheters
with wires disposed within pockets produced by inward, neutral and
outward biasing, respectively;
[0039] FIGS. 9a-9c are cross-sectional views of examples of the
various configurations of the outer layer disposed over the
balloon;
[0040] FIG. 10 is a cross-sectional view of a balloon catheter
showing the concentration of force through each of four wires that
are disposed within their respective pockets;
[0041] FIG. 11 is a cross-sectional view of a balloon attached to a
sheath, the sheath encapsulating a wire therewithin;
[0042] FIG. 12 is a perspective view of a tubular-shaped sheath
encapsulating a wire;
[0043] FIG. 13 is a mold assembly for blow molding a balloon with
encapsulated wires in a tubular-shaped sheath;
[0044] FIG. 14 is a cross-sectional view of one end of a tubular
sheath extending past an end of a wire;
[0045] FIG. 15 is a cross-sectional view of one end of a tubular
sheath having a beveled end and extending past an end of a wire;
and
[0046] FIG. 16 is a cross-sectional view of a balloon attached to a
sheath, the sheath having a cutting edge and encapsulating a wire
therewithin;
[0047] FIG. 17 is a perspective view of a balloon catheter with one
wire disposed within a pocket and another wire secured to a
retaining element; and
[0048] FIG. 18 is a perspective view of a balloon catheter with two
wires each disposed within their respective pockets.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] The embodiments are described with reference to the drawings
in which like elements are referred to by like numerals. The
relationship and functioning of the various elements of the
embodiments are better understood by the following detailed
description. However, the embodiments as described below are by way
of example only, and the invention is not limited to the
embodiments illustrated in the drawings. It should also be
understood that the drawings are not to scale and in certain
instances details have been omitted, which are not necessary for an
understanding of the embodiments, such as conventional details of
fabrication and assembly.
[0050] Referring now to the drawings in FIGS. 1-18, a balloon
catheter with wires is shown. As will be discussed, the wires may
be disposed within a sheath or a pocket. The wires may be wrapped
into the folds of the balloon. However, for purposes of clarity,
the Figures do not show such a pleated configuration to enable
illustration of the wires within their pockets and connection of
the wires to the balloon and shaft.
[0051] FIG. 1 shows an exemplary balloon catheter 100 having wires
110 and 120 disposed within pockets 111 and 121, respectively. The
balloon catheter 100 includes a shaft 170 and a balloon 140. The
catheter shaft 170, as shown in FIG. 1, may have a diameter ranging
between about 3 FR and about 12 FR. Preferably, the shaft 170 has a
diameter of about 7 FR.
[0052] The balloon 140 is shown in its inflated state. An outer
surface of the balloon 140 has a working diameter, denoted as WD,
which extends along a part of the length of the balloon 140.
Typically, the working diameter of the balloon 140 is a portion
that inflates to a generally uniform circumference in order to
evenly dilate a section of a lumen. However, the working diameter
does not necessarily need to have a uniform circumference. The
working diameter of the balloon 140 may be connected to the shaft
170 with a tapered proximal portion 190 and a tapered distal
portion 191. The length of the working diameter may be defined as
the distance between the balloon proximal end 141, where the
tapered proximal portion 190 meets the working diameter, and the
balloon distal end 142, where the tapered distal portion 191 meets
the working diameter.
[0053] Still referring to FIG. 1, the pocket 111 has an opening 112
through which the wire 110 may be inserted. The wire 110 extends
within the pocket 111. Similarly, the pocket 121 has an opening 122
through which wire 120 may be inserted. The wire 120 extends within
the pocket 121. Pockets 111, 121 have interior spaces for the
respective wires 110, 120 to be disposed within. Pocket 111 has a
continuous seam 113 that may constrain the wire 110 within the
interior space. The seam 113 represents the locations where an
outer layer 130 is disposed over and bonded to the outer surface of
the balloon 140. The distal end 114 of the seam 113 may be sealed
off, thereby preventing the wire 110 from extending therethrough.
Pocket 121 also has a continuous seam 123 that constrains the wire
120 within the interior space. The seam 123 represents the
locations where the outer layer 130 is disposed over and affixed to
the outer surface of the balloon 140. The distal end 124 of the
seam 123 is sealed off, thereby preventing the wire 120 from
extending therethrough. Regions 135, 136 and 137 represent
locations where the outer layer 130 has been bonded to the outer
surface of the balloon 140. The outer layer 130 may be bonded to
the outer surface of the balloon 140 by a variety of ways known to
one of ordinary skill in the art, including heat bonding, adhesive
bonding, or solvent bonding. These types of bonding will be
explained in greater detail below.
[0054] A retaining element 160 may secure wire 110 and/or wire 120
in position. The retaining element 160 prevents wires 110, 120 from
sliding out of their respective pockets 111, 121. Because the
proximal hub is where the largest diameter of the balloon catheter
100 resides, it is preferable to have the retaining element 160
located on the proximal hub of the balloon 140, as shown in FIG.
1.
[0055] Alternatively, the wires 110 and 120 may be loosely disposed
within their respective pockets 111 and 121, as shown in FIG. 18.
The wires 110 and 120 are not attached to the retaining element
160. FIG. 18 shows that the opening 112 of pocket 111 and opening
122 of pocket 121 may be sealed off to enclose the wires 110, 120
within the interior regions of the pockets 111, 121. The seal may
include a suture or adhesive. Other ways of sealing the openings
112, 122 of the pockets 111, 121 are contemplated and may be
obvious to one of ordinary skill in the art.
[0056] FIG. 17 shows yet another type of balloon catheter in which
one of the wires is loosely disposed within a pocket and the other
wire is attached to a retaining element. Specifically wire 110 is
loosely disposed within pocket 111, and the proximal end of wire
120 extends from pocket 121 and attaches to retaining element
160.
[0057] Referring back to FIG. 1, although two wires are shown
disposed within their respective pockets, more than two wires may
be disposed within a single pocket. Preferably, each wire resides
in its own pocket. Additionally, although the wires 110, 120 are
shown extending parallel to the longitudinal axis of the balloon,
the wires 110, 120 may be configured in a non-parallel arrangement
such as a helical arrangement around the working diameter of the
balloon 140.
[0058] The composite thickness of the balloon 140 and outer layer
130 remain relatively thin such that they can be folded in the
conventional pleated arrangement during delivery to achieve a small
profile. Preferably, the outer layer 130 does not provide a
hindrance to the folding or pleating process.
[0059] Various types of pocket configurations are contemplated.
FIGS. 2a-2c show examples of different pocket geometries. FIG. 2a
shows a configuration in which the outer layer 130 is selectively
attached to various locations around the balloon 140. The outer
layer 130 is unattached to the balloon along four locations to
produce pockets 230, 240, 250, 260. The points of attachment 274a
of the outer layer 130 to the balloon are relatively low-contact
area bonds. The low-contact area bonds allow the width of the
pockets 230, 240, 250, 260 to be greater than the diameter of their
respective wires 290, 291, 292, 293 disposed therewithin, thereby
providing the wires 290, 291, 292, 293 free space to move within
the interior regions of the pockets 230, 240, 250, 260. The free
space surrounding each of the wires 290, 291, 292, 293 within the
interior regions of their respective pockets 230, 240, 250, 260 may
allow the wires 290, 291, 292, 293 to flex during navigation of the
balloon catheter through tortuous regions. The ability of the wires
290, 291, 292, 293 to flex may help maintain the wires 290, 291,
292, 293 on the balloon 140 (FIG. 1) without a high risk of tearing
from the surface of the balloon 140. Additionally, the free space
surrounding each of the wires 290, 291, 292, 293 within their
respective pockets 230, 240, 250, 260 enables any longitudinal
movement that the pockets 230, 240, 250, 260 may undergo upon
inflation of the balloon 140 without undue stress on the wires 290,
291, 292, 293.
[0060] FIG. 2b shows a configuration in which the outer layer 130
is selectively attached to various locations around the balloon
140. The regions of attachment 274b of the outer layer 130 to the
balloon 140 can be characterized as intermediate-contact area bonds
relative to the contact areas shown in FIG. 2a. The outer layer 130
is unattached to the balloon 140 along four locations to produce
pockets 230, 240, 250, 260 in which respective wires 290, 291, 292,
293 are disposed therewithin. The intermediate-contact area bonds
cause the pockets 230, 240, 250, 260 to be smaller than the pockets
illustrated in FIG. 2a.
[0061] FIG. 2c shows a configuration in which the regions of
attachment 274c of the outer layer 130 to the balloon 140 can be
characterized as high contact-area bonds relative to the contact
areas shown in FIGS. 2a and 2b. The high contact-area bonds produce
pockets 230, 240, 250, 260 in which respective wires 290, 291, 292,
293 are disposed therewithin. The high-contact area bonds cause the
pockets 230, 240, 250, 260 to be smaller than the pockets
illustrated in FIGS. 2a and 2b.
[0062] There are various ways to apply the outer layer 130 to the
outer surface of the balloon 140, as shown in FIGS. 3-5. For
example, FIG. 3 shows that the outer layer 130 may be a sheet that
can be wrapped around the outer surface of the balloon 140.
Alternatively, FIG. 4 shows that the outer layer 134 may be a
cylindrical sleeve wrapped around the outer surface of the balloon
144. FIG. 5 shows that the outer layer 135 is formed from another
portion of a balloon in which one end of it has been removed and
slid over the underlying balloon 145. Preferably, the outer balloon
135 is slid over the underlying balloon 145 with the underlying
balloon 145 in its deflated state to create an intimate fit between
the two balloons 135 and 145. After achieving the fit, the balloons
135 and 145 may be partially inflated and thereafter bonded to one
another via heat bonding, adhesive bonding, or solvent bonding. The
outer layer 135 may be surface treated (e.g., roughened) in order
to improve the adhesion at the bond sites between the balloon 145
and the outer layer 135. As FIG. 5 shows, the outer layer 135 may
span beyond the working diameter of the underlying balloon 145 to
facilitate handling or sealing. Other ways of attaching the outer
layer 135 to the underlying balloon 145 are contemplated and may be
obvious to one of ordinary skill in the art.
[0063] After the outer layer 130 has been attached to the balloon
140 (FIG. 3), the pockets may be formed. FIG. 6 is an example of
selectively heat bonding or laser bonding the outer layer 130 at
predetermined regions to the balloon 140. In particular, FIG. 6
shows the result of heat bonding or laser bonding the outer layer
130 to the balloon 140 to form a continuous seam 600. In other
words, the seam 600 represents the points that the outer layer 130
is bonded to the balloon 140. The seam 600 has a serpentine
configuration which extends around the circumference of the working
diameter of the balloon 140. Because the outer layer 130 is only
attached to the balloon 140 at the seam 600, pockets 610, 620, 630,
640 are formed proximal and distal to the undulating seam 600. In
other words, the pockets are accessible from both the distal end
and proximal end of the balloon 140. Because the seam 600
symmetrically extends around the circumference of the balloon 140,
there are also four pockets on the opposite 180.degree. of the
balloon 140, which are not shown. All eight of the pockets are
equally spaced apart. One wire may be slidably disposed into each
pocket. For example, one wire may slide along the distal direction
into pocket 610, as indicated by the arrow pointing into pocket
610, while another wire may slide along the proximal direction into
pocket 620, as indicated by the arrow pointing into pocket 620.
[0064] Because the balloon 140 will be movable from a deflated
state to an inflated state, the wires may have a tendency to slide
out of the pocket 610, 620, 630, 640 and/or the pockets 610, 620,
630, 640 may have a tendency to longitudinally move relative to the
wires. Consequently, a retaining element 160 such as a collar (FIG.
1), may be fastened to the wires to maintain the positioning of the
wires in their respective pockets 610, 620, 630, 640.
Alternatively, the openings of the pockets 610, 620, 630, 640 that
the wires slide into may be sealed to confine the wire within the
pockets 610, 620, 630, 640. As an example, the openings may be
sutured, heat bonded, or sealed with an adhesive. If the openings
of the pockets 610, 620, 630, 640 are sealed, then the individual
wires preferably have an axial length approximating the axial
length of the pockets 610, 620, 630, 640.
[0065] Nonetheless, it may be preferable to allow the wires to move
within the pockets to enable them to flex and bend. This feature
may be advantageous, for example, as the balloon is being navigated
through tortuous body lumens. Thus, a non-adhesive coating, which
is also known as a release agent, may be applied to one or more
surfaces of the wires to prevent the wires from adhering to the
inner surfaces of the pockets 610, 620, 630, 640.
[0066] Although the seam 600 has been shown to be a
serpentine-configured heat bonded or laser bonded line, other
shapes of the seam 600 are possible. The shape of the seam 600 may
determine the geometry of the pockets 610, 620, 630, 640 that the
wires are inserted into.
[0067] FIG. 7 shows another way that pockets may be formed. A
removable mechanical mask 710 is shown overlying an outer surface
of the balloon 140. The mask 710 may be formed from a variety of
materials such as Teflon. The mask 710 may have a fingerlike-like
structure. The mask 710 acts to block bonding between the outer
surface of the balloon 140 and the outer layer 130. FIG. 7 shows
the mask 710 positioned over the balloon 140. With the mask 710
positioned over the balloon 140, as shown by the arrow in FIG. 7, a
light sensitive adhesive may be applied to the outer layer 130 or
both the outer layer 130 and the outer surface of the balloon 140
along regions 716 and 717. In other words, adhesive is applied to
bond those areas of the balloon 140 with the outer layer 130 that
are not covered by the mechanical mask 710. Any adhesive known to
one of ordinary skill in the art may be used. After the adhesive
has cured such that the bond has stabilized, the mask 710 may be
removed. As shown, the fingers of the mask 710 may be designed to
be tapered or inclined relative to the surface of the balloon 140
so that the mask 710 may be relatively easy to withdraw after the
adhesive has cured over regions 716 and 717. The proximal end of
the mask 710 may extend past the proximal end of the balloon 140,
as shown in FIG. 7, for easy handling of the mask 710. Masked
regions 715 and 720 may correspond to the interior space of the
newly formed pockets 715 and 720. The locations at which the
balloon 140 bonds to the outer layer 130 form the seam of pockets
715 and 720. Two additional pockets may also be formed on the other
side of the balloon 130 to create a total of four pockets. As an
alternative to a mechanical mask 710, a chemical mask may be
utilized. Any type of chemical mask known to one of ordinary skill
in the art may be used, including oils and lubricants. Removal of
the chemical mask may involve chemically rinsing with an inert
chemical that may not react with the outer layer 130, which is now
bonded to the outer surface of the balloon 140. Because there is no
chemical interaction between the layers when adhesive bonding is
used, the outer layer 130 may be formed from a material dissimilar
from the balloon 140.
[0068] Larger pockets of FIGS. 6 and 7 as compared to FIG. 8 might
be advantageous when negotiating tortuosity and making sure that
the wires rest in their intended positions during folding
operations.
[0069] Referring back to FIG. 1, the pockets may be created
utilizing a chemical process known as solvent bonding. Unlike the
methods of forming pockets discussed in FIGS. 6 and 7, the pockets
of FIG. 1 may be created directly around the wires. The pockets
111, 121 that are created in FIG. 1 have a smaller interior space
relative to the pockets shown in FIGS. 6 and 7. The pockets 111,
121 of FIG. 1 may be created as follows. The wires 110 and 120 of
FIG. 1 are held in their desired position along the balloon 140
before the pockets 111, 121 are formed around the wires 110, 120.
With the wires 110 and 120 selectively positioned along the balloon
140, the outer layer 130 is solvent bonded to the balloon 140.
Solvent bonding involves the following. A solvent is applied to the
outer layer 130 and balloon 140. A suitable solvent is selected
that causes both the outer layer 130 and the balloon 140 to
partially dissolve with the solvent. The dissolution of the outer
layer 130 and the balloon 140 causes liquefaction along regions
135, 136 and 137. The solvent may evaporate at ambient temperature
or can be driven off with heat. When the solvent evaporates, the
outer layer 130 and the balloon 140 will re-solidify. As they
re-solidify, the outer layer 130 and balloon 140 become bonded.
Pressure may be applied to the outer layer 130 and balloon 140 to
hold them together as the solvent evaporates. Any type of solvent
known to one of ordinary skill in the art may be used, including
acetone, toluene, methylene chloride, and methyl ethyl ketone.
[0070] In the solvent bonding method, a mask may not be required as
the wires 110, 120 may prevent the outer layer 130 from solvent
bonding to the balloon 140 within the local area where the wires
110, 120 reside. Alternatively, a release agent or surface
treatment may be applied to the wires 110, 120 to further prevent
any tendency the wires 110, 120 may have to adhere to the outer
layer 130.
[0071] Note that in all of the examples of pocket formation
discussed, the balloon 140 is preferably at least semi-inflated
when the outer layer 130 is bonded to the balloon 140. Applying the
outer layer 130 to at least a semi-inflated balloon 140 may enable
greater control of where the bonds are formed.
[0072] FIGS. 8a-8c illustrate the concept of biasing. The term
"biasing" as used herein refers to whether the pockets protrude
radially inward or radially outward relative to the surface of the
balloon. As an example, the pocket configuration shown in FIG. 2c
may be modified to produce the pocket arrangements shown in FIGS.
8a-8c. Generally speaking, the extent to which a bias is created
may be determined by the net pressure exerted by the balloon and
the net pressure exerted on the balloon as the outer layer is added
over the surface of the balloon.
[0073] FIG. 8a shows pockets 810, 820, 830, 840 having an inward
bias. The inward bias is created by a controlled balance of various
fabrication factors, including the tension of any mask being
utilized, the inflation pressure of the balloon 140, and the
tightness of the outer layer 130 over the balloon 140. Creation of
an inward bias results from the net pressure on the balloon 140
being greater than the net pressure exerted by the balloon 140.
FIG. 8b shows pockets 810, 820, 830, 840 that have a neutral bias
in which the net pressure exerted against the balloon 140 is
exactly offset by the net pressure exerted by the balloon 140. FIG.
8c shows pockets 810, 820, 830, 840 that have an outward bias in
which the net pressure exerted against the balloon 140 is greater
than the net pressure exerted on the balloon 140.
[0074] Selecting an inward, outward, or neutral bias will depend on
numerous factors, including the target site that the balloon
catheter is to be delivered to and the desired delivery profile of
the balloon catheter as it navigates through tortuous vessels.
[0075] FIGS. 9a-9c show examples of the various configurations of
the outer layer and types of outer layers that are contemplated.
FIG. 9a illustrates an outer layer 130a that partially
circumscribes the wires to form the required pockets. The outer
layer 130a may be a ribbon, coating or covering. However, the outer
layer 130a does not wrap completely around the balloon 140a. Such a
configuration may be advantageous from a manufacturing standpoint.
FIG. 9b illustrates that the outer layer 130b may be a continuous
tubular sleeve that coaxially slides over the balloon 140b. FIG. 9c
shows an outer balloon portion forming the outer layer 130c.
[0076] In all of the various examples that have been discussed, it
is desirable for the wires to not adhere to any of the inside
surfaces of the pockets. Having an unattached wire confined within
a pocket enables longitudinal compliance of the wire in which the
wire may readily conform to the changes in shape that the pocket
undergoes as the balloon 140 moves from a relatively flat deflated
state to a relatively cylindrical inflated state. Additionally, an
unattached wire may readily flex when the balloon is being
navigated through tortuous body lumens, thereby reducing the risk
that a tightly attached wire may be torn from the surface of the
balloon 140.
[0077] Utilizing a balloon catheter in which the wire is confined
within a pocket may offer numerous advantages over a balloon
catheter in which the wire is exposed. Because the wire is
contained within two layers, it is naturally shielded from tissue
and therefore cannot inadvertently catch on tissue or damage
healthy tissue. These advantages reduce the need to undergo normal
balloon folding operations in which pleats are created within the
balloon. Thus, the wires are significantly more atraumatic as
compared to wires that remain exposed over the balloon surface.
[0078] Furthermore, having wires that are confined in their
respective pockets allow the wires to remain spaced apart at their
predetermined gaps during fracturing of calcified lesions. On the
other hand, balloon catheters with exposed wires which are affixed
at one or both ends of the shaft may have a tendency to move
relative to one another during inflation of the balloon, thereby
making control of the relative location of the wires more
difficult. As a result of the inadvertent movement, the wires may
move to an undesired location on the balloon catheter that fails to
contact a calcified lesion. Additionally, because calcified lesions
can be asymmetric being built-up on only side of the wall of a body
lumen, when a balloon catheter with exposed wires encounters a
calcified lesion, there may be a tendency for the balloon to
inflate towards a particular side of the body lumen. Thus, exposed
wires may have a tendency to move toward a particular side that
fails to contact the lesion. Furthermore, spinning of the balloon
may cause exposed wires to inadvertently catch on tissue, thereby
not allowing the wires to move with the balloon to the desired
lesion. Therefore, wires that are confined and can only move within
the interior space of the pockets may significantly reduce the risk
of inadvertent movement of the wires.
[0079] Referring to the structure of FIG. 1, the positioning of the
wires 111, 121 about the circumference of the balloon 140 may
generally be determined by the geometry of the stenosis. For
example, if an asymmetric stenosis is being treated, a greater
number of the wires may be positioned adjacent to the thickest part
of the stenosis.
[0080] One or more wires may be selectively positioned about the
balloon. The optimal number of dilation wires may vary depending on
the severity and type of stenosis to be dilated. Preferably, the
number of wires will be at least two and the wires will be
equidistant from each other.
[0081] Various shapes of the wires may be used. Differing wire
shapes enable the force that is concentrated on the vessel wall to
be varied as desired. For instance, a D-shaped cross-sectional wire
may in certain applications be preferable over a circular-shaped
cross-sectional wire. The D-shaped cross-sectional wire may
increase the area of the wire in contact with the balloon, relative
to the area of the circular-shaped wire in contact with the
balloon. The D-shaped wire may also minimize the area that contacts
the vessel, relative to the area of the circular-shaped wire in
contact with the vessel. Accordingly, a higher stress may be
exerted against the vessel wall by the D-shaped wire relative to
the circular-shaped wire. As another example, a V-shaped
cross-sectional wire may also be used.
[0082] If a substantially round cross-sectional configuration for
the dilation wires is used, the diameters may vary depending on the
particular blood vessel in which the stenosis is found and the size
of the remaining lumen within the blood vessel. For round wires, a
diameter of about 0.25 mm to about 0.5 mm is generally
preferred.
[0083] Although longitudinally extending wires have been described,
the wires may also be formed to have other shapes in their relaxed
state. For example, the wires may be helixes that wrap around the
balloon. Other shapes are also possible. Such configurations of the
wires may be preferable for the purpose of minimizing the profile
of the balloon catheter during delivery to a target site as well as
fracturing plaques having a tortuous geometry around a blood
vessel.
[0084] The dilation mechanism will now be described. FIG. 10 is a
partial cross-sectional view of a balloon catheter taken along a
plane that is distal to the inflation lumen of a balloon 910. FIG.
10 shows the balloon 910 in an inflated state. Generally speaking,
the dilation mechanism involves a technique in which the forces
resulting from inflating an angioplasty balloon in a stenosis are
concentrated and focused at one or more locations within the
stenosis. While the technique has been shown to be useful in
resolving resistant stenoses, it may also minimize the vascular
trauma associated with balloon angioplasty and subsequently improve
the outcome.
[0085] Referring to FIG. 10, the pockets 905-908, in which the
dilation wires 901, 902, 903, 904 reside, resist complete expansion
of the balloon 910 at the balloon-pocket interfaces. As a result of
the resistance, the balloon 910 does not reach its fully inflated
circumference. The balloon-pocket interfaces are shown as recessed
due to the resistance of the pockets 905-908 against the surface of
the inflated balloon 910.
[0086] The balloon 910 may radially expand to the circumference
shown in FIG. 10. The inflation pressure causes the balloon 910 to
exert a force against each of the pockets 905-908. The force
exerted at each of the balloon-pocket interfaces is designated as F
in FIG. 10. This causes the pockets 905-908 to push out toward the
vessel wall 950.
[0087] The dilation wires 901, 902, 903, 904, which are positioned
between the outer layer 911 and the balloon 910, focus the force,
F, of the balloon 910 at their respective points of contact of the
pockets 905, 906, 907, 908 with the vessel wall 950, as shown by
arrows 960, 970, 980 and 990 of FIG. 10. Additionally, the dilation
wires 901, 902, 903, 904 distribute the force longitudinally along
the length of the balloon 910. This force concentration allows the
dilation wires 901, 902, 903, 904 to exert a higher stress at their
respective points of contact of the pockets 905, 906, 907, 908 with
the vessel wall 950 as compared to conventional angioplasty
balloons.
[0088] The force concentration feature enables dilation of the
blood vessel 950 and/or cracking of the calcification rings
contained in the blood vessel 950 at a relatively lower inflation
pressure as compared to conventional angioplasty balloons. For
example, the balloon catheter of FIG. 10 is adapted to burst a
calcification ring surrounding a blood vessel at an inflation
pressure ranging between about 3 atm to about 30 atm, but
preferably in the range of about 4 atm to about 10 atm. The exact
inflation pressure is dependent upon numerous factors, including
the diameter and geometry of the dilation wires 901, 902, 903, 904
used. Conventional angioplasty balloons may utilize inflation
pressures of about 12 atm. A lower inflation pressure is
advantageous because it reduces the trauma to the vessel wall
950.
[0089] Additionally, the stress exerted by the dilation wires 901,
902, 903, 904 is predictable and controlled, often requiring a
single inflation. Because the dilations are predictable, controlled
and often isolated to the stenosed segment of the vessel wall 950,
restenosis may be limited to occurring only at the points of
contact where the dilation wires 901, 902, 903, 904 exert a stress
at their respective points of contact with the vessel wall 950.
Conventional percutaneous transluminal coronary angioplasty (PTCA)
procedures typically involve unpredictable points of rupture along
the entire circumference of the blood vessel, which often results
in more substantial vessel damage to the entire wall. Additionally,
multiple inflations may be required to fracture a calcification
ring.
[0090] The highest degree of cellular proliferation following
balloon angioplasty typically occurs in areas with the greatest
degree of vessel disruption. Therefore, the ability to dilate a
stenotic region in a more controlled and less disruptive manner at
a lower pressure, as described with respect to FIG. 10, may
potentially minimize the degree of restenosis. Compared to PTCA
procedures, the dilation wires 901, 902, 903, 904 may be capable of
providing a controlled dilatation in which the injury to the vessel
wall is localized to the dilation site only. The balloon catheter
of FIG. 10 may require relatively lower inflation pressures and a
relatively smaller number of inflations to produce significant
increases in luminal cross section as compared to conventional
angioplasty balloons.
[0091] Thicknesses of the balloon 140 and the outer layer 130 may
vary depending on the particular application of the balloon
catheter 100. However, generally speaking, to enhance the stress
concentration feature that has been described above, it may be
advantageous for the outer layer 130 to be thinner than the balloon
layer 140 at the point where the wire contacts the vessel wall.
[0092] The wires have been described as occupying the interior
space of a pocketed region. However, other ways of confining the
wire are contemplated. For example, each of the wires of the
balloon catheter may be encapsulated within a sheath, as shown in
FIG. 11. The term "encapsulated" as used herein refers to complete
circumscribing of the wire in the radial direction. FIG. 11 shows
each of four wires 1100, 1110, 1120, 1130 encapsulated within their
respective sheaths 1140, 1150, 1160, 1170. Each of the sheaths
1140, 1150, 1160, 1170 is attached to an outer surface of the
balloon 1180, the balloon 1180 shown in its inflated state. In the
example of FIG. 11, the sheaths 1140, 1150, 1160, 1170 are spaced
90 degrees apart about the balloon 1180. The sheaths 1140, 1150,
1160, 1170 may be attached to the outer surface of the balloon 1180
in a variety of ways known to one of ordinary skill in the art. As
an example, the sheaths 1140, 1150, 1160, 1170 may be fusion bonded
to the balloon 1180, as will be discussed in greater detail
below.
[0093] FIG. 12 shows one example of a wire-sheath arrangement. A
wire 1210 is inserted and encapsulated within a polymeric sheath
1200. The wire 1210 may have a circular cross-section to fit within
the polymeric sheath 1200, which may be tubular shaped. The wire
1210 may be inserted into a separate polymeric tube. Alternatively,
the polymer may be coated onto the wire 1210 by dip coating, spray
coating, extrusion, and other polymer coating techniques. The
polymeric sheath 1200 may be formed from any polymeric material
known to one of ordinary skill in the art. The polymeric sheath
1200 may be formed from heat-shrink tubing. Preferably, the balloon
and the polymeric sheath 1200 are the same materials to facilitate
fusion bonding, as will be discussed below, between the balloon and
the sheath 1200. Examples of materials that the balloon and sheath
1200 may be formed from include nylon and other polyamides,
polyethyleneterepthalate (PET), polyvinylchloride (PVC),
polypropylene, polyethylene, polyurethane and high density
polyethylene. The wire 1210 may be coated with a non-adhesive
coating to minimize bonding between the wire 1210 and the sheath
1200. Examples of a non-adhesive coating include a silicone release
or a fluorinated polymer such as PTFE and FEP. This may allow the
sheath 1200 to stretch in the axial direction with the balloon
without the sheath 1200 significantly pulling on the wire 1210. As
a result, the balloon may be free to axially expand without
significant restraint.
[0094] The wire-sheath arrangement may be fusion bonded to the
balloon during stretch blow molding of the balloon. The balloon may
be formed inside a metal mold from extruded polymer tubing. FIG. 13
shows a cross-section of a metal mold assembly 1300. The mold
assembly 1300 includes a cavity 1310 in which a parison is
introduced. The parison may be stretched mechanically with a
stretch rod. Low pressure air may be introduced into the parison to
blow a bubble. The parison is thereafter blow molded into the shape
of the balloon as known in the art. Axial stretching of the balloon
may also occur to achieve a thinner wall thickness along the neck
area of the balloon.
[0095] FIG. 14 shows the wire-sheath arrangement prior to being
fused during the blow molding operation. The part of the tube 1200
that extends past the wire 1210 may be pressed down and fused
during blow molding, resulting in the structure of FIG. 15.
[0096] Four grooves 1351, 1352, 1353, 1354 are shown adjacent to
the cavity 1310. A circular wire with an overlying tubular sheath
may be inserted in each of the four grooves 1351, 1352, 1353, 1354.
Pressurized air is fed into the cavity 1310 and introduced into one
end of the parison to expand it to form the balloon. The other end
of the parison is capped off during the air pressurization. The
expansion of the parison during the blow molding process fuses the
outer surface of the balloon to the polymer sheath (FIG. 12). To
maintain the wire and its overlying polymeric sheath in its
predetermined position within the grooves 1351-1354 during the blow
molding process, magnets 1311, 1312, 1313, 1314 may be placed in
the mold adjacent to the grooves 1351, 1352, 1353, 1354. The wires
may be any type of a magnetic metal or alloy. As an example, the
magnetic alloy may be a series 400 stainless steel. Other methods
may be used to fixate the wire-sheath arrangements within their
respective grooves 1351-1354 during the blow molding process.
[0097] The wire 1210 and sheath 1200 of FIG. 12 preferably extend
along the entire length of the working diameter of the balloon 140
(FIG. 1). The sheath 1200 preferably encapsulates the wire 1210 on
both ends. FIG. 15 shows that the sheath 1200 may encapsulate the
ends of the wire 1210. FIG. 15 shows that the sheath 1200 has a
beveled edge to more completely encapsulate the wire 1210.
Alternatively, free space may exist for the wire 1200 to move as
the sheath 1200 axially stretches and contracts during balloon
inflation and deflation.
[0098] FIG. 16 shows that the sheath may have an edge to enable
cutting of a lesion. FIG. 16 shows a sheath 1620 with an edge 1610
having a wire 1630 disposed within the sheath 1620. The sheath 1610
may be fusion bonded to a surface of the balloon 1660. The edge
1610 may be formed as follows. The grooves 1351, 1352, 1353, 1354
shown in FIG. 13 may be machined such that they converge to a point
1355 at the radially outward side. The tubular-shaped polymer
sheath is inserted into the groove around its respective wire. The
blow molding process forces some of the material of the sheath to
flow into the pointed region of the machined groove, thereby
creating the cutting edge 1610 shown in FIG. 16. The cutting edge
1610 may enable tearing or breaking of a lesion from a vessel.
[0099] The cutting edge 1610 may be advantageous over other
approaches. For example, it is more advantageous than conventional
angioplasty because it utilizes the concept of focused force
angioplasty to fracture lesions. On the other hand, utilizing the
cutting edge 1610 may be more advantageous than metal blades
because the cutting edge 1610 may be less likely to injure a vessel
wall as compared to the metal blades.
[0100] The wall thickness of the sheath 1200 (FIG. 12) depends on
several factors. The wall thickness preferably is thin enough to
maximize the focusing or transmission of force to the stenosed
region of the vessel wall yet sufficiently thick to prevent
breakthrough of the wire 1210 through the sheath 1200. Furthermore,
a wall thickness that is too thick may render the balloon catheter
too longitudinally stiff such that the balloon catheter loses its
ability to negotiate through tortuosity of various vessels.
However, a cutting edge 1610 as shown in FIG. 16 requires a thicker
sheath in order for extra material to flow into the pointed grooves
1351, 1352, 1353, 1354 of the mold assembly 1300. Thus, one of
ordinary skill in the art would be able to balance these competing
factors in light of the particular application the balloon catheter
is to be used for to arrive at the optimal wall thickness of the
sheath 1200. In one example, the sheath 1200 may have a wall
thickness about equal to or on the same order of magnitude as the
balloon 1660 wall thickness.
[0101] Although FIG. 12 shows a tubular-shaped sheath 1200, the
sheath may possess any shape. Preferably, the sheath has the same
shape as the wire such that the sheath can completely circumscribe
and encapsulate the wire.
[0102] Having encapsulated wires within a sheath offers similar
advantages as described above with respect to confining the wires
within pockets. The wires are atraumatic as they are shielded from
contacting body tissue. The wires also remain oriented in their
predetermined position along the balloon catheter, thereby
eliminating the risk that the wires inadvertently move relative to
each other.
[0103] The above figures and disclosure are intended to be
illustrative and not exhaustive. This description will suggest many
variations and alternatives to one of ordinary skill in the art.
All such variations and alternatives are intended to be encompassed
within the scope of the attached claims. Those familiar with the
art may recognize other equivalents to the specific embodiments
described herein which equivalents are also intended to be
encompassed by the attached claims.
* * * * *