U.S. patent application number 14/150996 was filed with the patent office on 2014-05-08 for catheter with radiopaque coil.
This patent application is currently assigned to Abbott Cardiovascular Systems Inc.. The applicant listed for this patent is Abbott Cardiovascular Systems Inc.. Invention is credited to Thomas Haslinger.
Application Number | 20140123463 14/150996 |
Document ID | / |
Family ID | 45852760 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140123463 |
Kind Code |
A1 |
Haslinger; Thomas |
May 8, 2014 |
CATHETER WITH RADIOPAQUE COIL
Abstract
A balloon catheter having a radiopaque coil embedded in the
catheter's body corresponding to a landmark of the balloon or other
location on the catheter body. The radiopaque coil can be viewed
under fluoroscopy to located the balloon or other structure of the
catheter. The coil can be readily inserted in the manufacturing
process by inserting it between two layers that form the catheter
body, and then sealing the coil inside the catheter at the desired
location. This facilitates both the manufacturing process and
prevents the marker from being dislodged during the manufacturing,
navigation, or inflation process.
Inventors: |
Haslinger; Thomas; (Sun
City, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Abbott Cardiovascular Systems Inc. |
Santa Clara |
CA |
US |
|
|
Assignee: |
Abbott Cardiovascular Systems
Inc.
Santa Clara
CA
|
Family ID: |
45852760 |
Appl. No.: |
14/150996 |
Filed: |
January 9, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13042792 |
Mar 8, 2011 |
8652098 |
|
|
14150996 |
|
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Current U.S.
Class: |
29/428 |
Current CPC
Class: |
Y10T 156/1062 20150115;
A61M 25/0012 20130101; A61F 2/958 20130101; Y10T 29/49826 20150115;
A61M 25/104 20130101; A61M 25/1036 20130101; A61M 25/0108
20130101 |
Class at
Publication: |
29/428 |
International
Class: |
A61M 25/01 20060101
A61M025/01; A61F 2/958 20060101 A61F002/958; A61M 25/10 20060101
A61M025/10 |
Claims
1-15. (canceled)
16. A method for making a catheter body comprising the steps of:
forming a composing catheter body having an inner layer and an
outer layer; cutting away a portion of the outer layer to expose
the inner layer; placing a radiopaque coil on the exposed inner
layer; and forming a new outer layer over the exposed inner layer
and the radiopaque coil to trap the radiopaque coil between the
inner layer and the new outer layer.
17. The method of claim 16, wherein a tie layer is interposed
between the first layer and the new outer layer to bond the first
layer to the second layer.
18. The method of claim 16 further comprising attaching an
inflation balloon to the outer layer.
19. The method of claim 18 wherein the radiopaque coil coincides
longitudinally with a proximal end of a working section of the
inflation balloon.
Description
BACKGROUND
[0001] This invention generally relates to intravascular balloon
catheters and systems for performing percutaneous transluminal
coronary angioplasty (PTCA) and/or stent delivery, and more
particularly to a catheter delivery system that uses a radiopaque
coil in the catheter structure to provide a visual indicator in the
system showing where a part of the catheter is located within a
body lumen.
[0002] PTCA is a widely used procedure for the treatment of
coronary heart disease. In this procedure, a balloon dilatation
catheter is advanced into the patient's coronary artery and the
balloon on the catheter is inflated within the stenotic region of
the patient's artery to open up the arterial passageway and thereby
increase the blood flow there through. To facilitate the
advancement of the dilatation catheter into the patient's coronary
artery, a guiding catheter having a pre-shaped distal tip is first
percutaneously introduced into the cardiovascular system of a
patient by the Seldinger technique or other method through the
brachial or femoral arteries.
[0003] The catheter is advanced until the pre-shaped distal tip of
the guiding catheter is disposed within the aorta adjacent the
ostium of the desired coronary artery, and the distal tip of the
guiding catheter is then maneuvered into the ostium. A balloon
dilatation catheter may then be advanced through the guiding
catheter into the patient's coronary artery over a guidewire until
the balloon on the catheter is disposed within the stenotic region
of the patient's artery. The balloon is inflated to open up the
arterial passageway and increase the blood flow through the artery.
Generally, the inflated diameter of the balloon is approximately
the same diameter as the native diameter of the body lumen being
dilated so as to complete the dilatation but not over expand the
artery wall. After the balloon is finally deflated, blood flow
resumes through the dilated artery and the dilatation catheter can
be removed.
[0004] In a large number of angioplasty procedures, there may be a
restenosis, i.e. reformation of the arterial plaque. To reduce the
restenosis rate and to strengthen the dilated area, physicians may
implant an intravascular prosthesis or "stent" inside the artery at
the site of the lesion. Stents may also be used to repair vessels
having an intimal flap or dissection or to generally strengthen a
weakened section of a vessel. Stents are usually delivered to a
desired location within a coronary artery in a contracted condition
on a balloon of a catheter which is similar in many respects to a
balloon angioplasty catheter, and expanded to a larger diameter by
expansion of the balloon. The balloon is then deflated to remove
the catheter and the stent is left in place within the artery at
the site of the dilated lesion.
[0005] To accurately place the balloon, and also the stent, at the
desired location, visual markers on the catheter are typically
utilized that are read by machines outside the body. For example,
in the case where a balloon catheter is used with an fluoroscope, a
radiopaque marker incorporated into the catheter body may be
observed visually on a screen while the procedure is taking place.
In many cases, the markers must be precisely located to ensure
accurate placement of the balloon in the affected area.
Incorporating markers into the catheter's or balloon's structure
can be expensive, and the markers can become dislodged when the
catheter is torqued during delivery or when the catheter's balloon
expands. For these reasons, a better and more economically feasible
method of incorporating a radiopaque marker into a balloon catheter
is needed.
SUMMARY OF THE INVENTION
[0006] The present invention is a catheter or catheter delivery
system that incorporates a coil made from a radiopaque material
that can be inserted between layers of a multi-layer catheter body.
The coil is placed, for example, over a first layer of a
multi-layer catheter body, and then a second layer of material is
formed over the first, capturing the radiopaque coil between the
two layers. Where the coil is disposed at, for example, the
beginning or end of the working length of the balloon, the
physician can accurately determine the precise location that the
balloon needs to be positioned under fluoroscopy by locating the
coil, which in turn identifies the beginning (or end) of the
balloon's working length.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an elevated, perspective view of a catheter
delivery system of the present invention;
[0008] FIG. 2 is a cross-sectional view of the catheter of FIG. 1
taken along lines 2-2;
[0009] FIG. 3 is a cross-sectional view of the catheter of FIG. 1
taken along lines 3-3;
[0010] FIG. 4 is a perspective view of the catheter as the outer
layer is being peeled back for removal;
[0011] FIG. 5 is a perspective view of the coil being placed over
the inner layer of the catheter;
[0012] FIG. 6 is an enlarged perspective view of the coil on the
inner layer of the catheter;
[0013] FIG. 7 is an enlarged view of the catheter with a new outer
layer placed over the coil and the inner layer;
[0014] FIG. 8 is an enlarged view, partially in shadow, of the
catheter with the balloon showing the position of the coil in a
first embodiment; and
[0015] FIG. 9 is a perspective view of the catheter balloon showing
the position of the coil in a second embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] FIG. 1 illustrates a balloon catheter of the type that can
benefit from the present invention. The catheter 10 of the
invention generally comprises an elongated catheter shaft 11 having
a proximal section, 12 a distal section 13, an inflatable balloon
14 formed of one or more polymeric materials on the distal section
13 of the catheter shaft 11, and an adapter 17 mounted on the
proximal section 12 of shaft 11. In FIG. 1, the distal portion of
the catheter 10 is illustrated within a patient's body lumen 18,
prior to expansion of the balloon 14.
[0017] In the embodiment illustrated in FIG. 1, the catheter shaft
11 has an outer tubular member 19 and an inner tubular member 20
disposed within the outer tubular member defining, with the outer
tubular member, an inflation lumen 21. Inflation lumen 21 is in
fluid communication with the interior chamber 15 of the inflatable
balloon 14. The inner tubular member 20 has an inner lumen 22
extending therein which is configured to slidably receive a
guidewire 23 suitable for advancement through a patient's coronary
arteries. The distal extremity 31 of the inflatable balloon 14 is
sealingly secured to the distal extremity of the inner tubular
member 20 and the proximal extremity 32 of the balloon 14 is
sealingly secured to the distal extremity of the outer tubular
member 19.
[0018] FIGS. 2 and 3 show transverse cross sections of the catheter
shaft 11 and balloon 14, respectively, illustrating the guidewire
receiving lumen 22 of the guidewire's inner tubular member 20 and
inflation lumen 21 leading to the balloon interior 15. The balloon
14 can be inflated by a fluid introduced at the port in the side
arm 24 into inflation lumen 21 contained in the catheter shaft 11,
or by other means, such as from a passageway formed between the
outside of the inner tubular member 20 and the outer tubular member
11, depending on the particular design of the catheter. The details
and mechanics of balloon inflation vary according to the specific
design of the catheter, and are well known in the art.
[0019] Typically balloon catheters of the type shown in FIG. 1
include radiopaque markers incorporated onto the inner tubular
member. These markers must be formed onto the inner tubular
member's surface, either through adhesives, mechanical attachment,
or embedded into the inner tubular member's material. As explained
above, there are shortcomings with incorporating radiopaque markers
relating to reliability of adhering the markers to the catheter
body as well as the fact that the procedure is expensive and
reduces the manufacturing yield of the catheters. The present
invention overcomes these shortcomings by implanting a radiopaque
coil into the catheter body, preferably at a location of interest
to the physician, so that the conventional balloon markers can be
omitted. FIGS. 4-7 illustrate the various steps of one method for
constructing the catheter of the present invention.
[0020] With reference to FIG. 4, a catheter body 11 is formed on a
mandrel 130 and may be formed, for example, as a dual-layer hollow
extrusion with a lubricious inner layer 100 of HDPE or ultra high
molecular weight polyethylene (UHMWPE) and an outer layer 105 of
nylon or Pebax, with or without the usual Primacor "tie layer" that
binds the inner layer 100 to the outer layer 105. To insert the
radiopaque coil into the catheter body, the outer layer 105 is
stripped away by peeling back tabs 115 until the scored portion 110
is readed, whereupon a coil placed over the inner layer 100.
Assembly begins with the following steps to remove a distal section
of the outer Pebax or nylon layer 105:
[0021] Step 1: At an appropriate distance from the distal end of
the catheter body 11, the outer layer of the HDPE/nylon or
HDPE/Pebax extrusion is circumferentially scored 110 using a
cutting instrument such as a razor blade or the like to create a
break point of the outer layer 105 only (FIG. 4). Care is called
for to control the scoring blade in order to protect the inner
layer 100.
[0022] Step 2: A longitudinal slit is made at the distal end of the
catheter body over a length of several millimeters or more using a
cutting knife such as a razor blade or equivalent, creating two
semi-circular halves at the distal end.
[0023] Step 3: To separate the outer layer 105 from the inner layer
100, both halves of the bisected end are folded or rolled back, and
a grasping tool such as tweezers or the like is used to grasp the
outer layer 105 at the semi-circular halves and pull them away from
the inner layer 100 of each half (FIG. 4). The outer layer 105 is
then peeled away from their respective inner layer to thus separate
and remove the outer layer until the score mark 110 is reached,
whereupon the outer layer halves 105a,b tear away from the catheter
body 11. The result is a stepped transition 140 between the exposed
HDPE inner layer 100 and the intact proximal remainder of the
extrusion's outer layer 105 (FIG. 5).
[0024] Next, a radiopaque coil 150 is slid over the exposed inner
layer 100 of the catheter (see arrow 170 of FIG. 5) and a second
coil may be added to the first coil. The coils 150 may, but not
need be, stacked, and a separation of the two (or more) coils can
provide a gap where the outer tubular member and the inner tubular
member make physical contact to help seal the coil therebetween.
Once the coil or coils 150 are in place, a new, lower durometer
coextrusion outer layer 180 is slid over the coil(s) 150 and the
inner layer 100 as shown in FIG. 7. The coextrusion 180 may include
an adhesive tie-layer (not shown) to help bond the new outer layer
180 to the inner layer 100. Placing the outer layer 180 over the
coil sandwiches the coil 150 inside the catheter's multi-layer
construction. The new outer layer 180 is butted against the old
outer layer 105, and a suitable length of shrink tubing may be
placed over the joint as is known in the art. A fluoropolymer
shrink tube material, such as FEP, is preferable due to its
non-stick nature. This region is then progressively heated to melt
bond the various segments 180 and 100 together and, where present,
allow a Primacor middle layer to adhere or "tie" the outer layer
180 to the underlying HDPE layer. Afterwards, the shrink tubing and
mandrel 130 are removed to leave the finished catheter body with
the radiopaque coil 150 embedded in the catheter body.
[0025] The resultant catheter has the radiopaque coil 150 embedded
in its construction and can be used to locate the balloon 14 or
other part of the catheter under fluoroscopy. In FIG. 8, the
catheter 11 can be seen with a balloon 14 mounted thereon such that
the coil 150 terminates at the end of the working section 51 of the
balloon 14. Under fluoroscopy, a physician would be able to locate
the coil 150 and immediately know where the working section 51 of
the balloon ends. This feature allows the physician to locate the
coil adjacent the lesion or obstruction and know with confidence
that the balloon 14 will be applied at the precise location where
the proximal end of the coil 150 begins. Alternatively, as shown in
FIG. 9, the coil 150 or coils can be placed along and co-terminus
with the working section of the balloon 14 (between 51 and 52). For
the catheter balloon 14 of FIG. 9, the coil 150 corresponds to the
beginning 52 and end 51 of the working portion of the balloon 14,
so the physician can locate the coil 150 under fluoroscopy and
place the balloon 14 precisely where it needs to be to accomplish
the greatest effectiveness. Other locations are also available,
such as at the beginning of the working section of the balloon for
example.
[0026] The outer layer 105 can be any durometer polymer, as
required by the application, and its inner layer 100 can be any
extrudable lubricious material. However, preferably the layer
materials should not adhere well to each other during extrusion,
because peeling off the outer layer 105 at the distal end would be
more difficult. The dual layer catheter may be E-beam irradiated,
particularly if its inner layer is HDPE (or UHMWPE), as this
promotes cross-linking and thus prevents undesirable material flow
of the inner layer during subsequent melt bonding operations.
[0027] The newly added outer layer segment 180 can be any durometer
polymer, as the application requires, but it is preferred that it
contain an inner surface of a "tie layer" material like Primacor in
order to promote secure bonding to the inner layer 100. The heat
needed for such bonding is preferably achieved by equipment that
provides localized and controllable heat with the ability to
traverse or rotate, and the required radial pressure is preferably
provided by shrink tubing which does not adhere well to the
underlying materials. Although it would be possible to simply heat
the assembly in an oven, this is less desirable because of a
greater tendency to trap air beneath the shrink tubing leading to
surface irregularities.
[0028] This invention is also applicable to inner members whose
inner layer 100 is a fluoropolymer such as PTFE. For example, the
inner layer 100 can be a single-layer extrusion that is
subsequently etched (e.g., sodium naphthalene or "Tetra Etch") to
promote bondability of its outer surface. An outer layer 105 is
then extruded onto the fluoropolymer tubing in a semi-continuous
(reel to reel) manner, with the extrusion parameters selected to
prevent melt bonding of the two layers. Thus, the outer layer 105
can be subsequently peeled away at one end to make room for the
installation of various durometers of outer jacket segments and
radiopaque coils 150. In this embodiment, the added segments do not
require an inner "tie layer' because they can be melt bonded
directly to the etched fluoropolymer surface, again using heat and
shrink tubing.
[0029] While particular forms of the invention have been
illustrated and described, it will be apparent to those skilled in
the art that various modifications can be made without departing
from the spirit and scope of the invention. Accordingly, it is not
intended that the invention be limited except by the appended
claims.
* * * * *