U.S. patent application number 16/935301 was filed with the patent office on 2020-11-05 for apparatus and methods for applying radiopaque identifiers to balloons.
The applicant listed for this patent is CLEARSTREAM TECHNOLOGIES LIMITED. Invention is credited to Hiep DO, Paul Fillmore, Andrew SCHAFFER.
Application Number | 20200345989 16/935301 |
Document ID | / |
Family ID | 1000004974875 |
Filed Date | 2020-11-05 |
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United States Patent
Application |
20200345989 |
Kind Code |
A1 |
DO; Hiep ; et al. |
November 5, 2020 |
Apparatus and methods for applying radiopaque identifiers to
balloons
Abstract
A medical balloon is provided for which the working surface may
be identified during an inverventional procedure with enhanced
precision. Related methods of manufacturing such a balloon are also
disclosed.
Inventors: |
DO; Hiep; (Chandler, AZ)
; SCHAFFER; Andrew; (Tempe, AZ) ; Fillmore;
Paul; (Tempe, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CLEARSTREAM TECHNOLOGIES LIMITED |
Enniscorthy |
|
IE |
|
|
Family ID: |
1000004974875 |
Appl. No.: |
16/935301 |
Filed: |
July 22, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14915064 |
Feb 26, 2016 |
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PCT/US2014/053162 |
Aug 28, 2014 |
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16935301 |
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61870913 |
Aug 28, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 48/09 20190201;
B29K 2105/258 20130101; B29L 2031/7543 20130101; B29C 49/04
20130101; B29C 51/008 20130101; B29C 48/0017 20190201; A61M
2025/1079 20130101; B29C 48/0022 20190201; A61M 25/10 20130101 |
International
Class: |
A61M 25/10 20060101
A61M025/10; B29C 51/00 20060101 B29C051/00; B29C 48/09 20060101
B29C048/09; B29C 48/00 20060101 B29C048/00; B29C 49/04 20060101
B29C049/04 |
Claims
1. A method of forming a medical balloon (12), comprising: forming
the medical balloon (12) having radiopaque and non-radiopaque
portions using a rotating die, wherein the radiopaque material is
applied so as to identify a working surface (W) of the medical
balloon (12), either by defining the edges of the working surface
(W), extending along the working surface (W), or extending along
portions of the balloon other than the working surface (W).
2. The method of claim 1, wherein the forming step comprises:
creating a balloon parison (60) using the rotating die; and blow
molding the balloon parison (60) into the medical balloon (12).
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/915,064 filed on Feb. 26, 2016, which is a
U.S. National Stage Application of PCT/US2014/053162 filed on Aug.
28, 2014, which claims the benefit of U.S. Provisional Patent
Application Ser. No. 61/870,913 filed on Aug. 28, 2013, the
disclosures of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] This disclosure relates generally to balloons for performing
medical procedures, such as angioplasty and, more particularly, to
a parison for forming a blow molded medical balloon having a
modified portion, such as a layer that is radiopaque, a medical
balloon, and related methods.
BACKGROUND OF THE INVENTION
[0003] Balloons are routinely used to resolve or address flow
restrictions or perhaps even complete blockages in tubular areas of
the body, such as arteries or veins. In many clinical situations,
the restrictions are caused by hard solids, such as calcified
plaque, and require the use of high pressures to compact such
blockages. Commercially available balloons employ complex
technology to achieve high pressure requirements without
sacrificing the profile of the balloon. Besides high pressure
requirements, the balloons should also be resistant to puncture,
easy to track and push, and present a low profile, especially when
used for angioplasty.
[0004] In clinical practice, angioplasty balloons are expanded from
a deflated, folded state to an expanded state within a vessel to
treat a target area, such as a portion of the circumferential inner
wall I of a blood vessel V, as shown in FIGS. 1 and 2. The
inflation is traditionally completed using an X-ray contrast agent
to provide better visibility under X-ray or other form of
radiography during the interventional procedure, as illustrated in
FIGS. 3 and 3a. Typically, a 70/30 percent mixture of contrast
agent and saline is used to inflate the balloon during an
angioplasty procedure.
[0005] In general, a desirable goal is to reduce inflation and
deflation times required for balloons without sacrificing the
profile of the balloons, especially for large volume balloons
(which can require up to two minutes of inflation/deflation times
with the contrast agent). Because of its relatively high viscosity,
it would also be desirable to eliminate, or at least reduce the
amount of, the contrast agent used in inflation/deflation of the
balloons. The use of contrast agent prolongs the
inflation/deflation times and also poses the risk of iodine
exposure to patients sensitive to iodine. In this regard, a
non-radiopaque substance could be used in lieu of the contrast
agent, such as for example saline or carbon dioxide, but such
substances are invisible during X-ray imaging, and thus do not
enhance visibility.
[0006] Furthermore, the physician performing the angioplasty
procedure should be able to locate the position of the uninflated
balloon with accuracy, so that the balloon will be properly
positioned once inflated. This is conventionally accomplished by
attaching marker bands on the catheter shaft in the region
corresponding to the balloon working surface. This "working
surface" is the surface along the portion of the balloon that is
used to achieve the desired treatment effect, such as contacting
the calcified plaque (which surface in the case of a balloon having
conical or tapering sections at the proximal and distal ends is
typically co-extensive with a generally cylindrical barrel
section).
[0007] Misalignment of the marker bands during placement along the
shaft sometimes results in their failure to correspond precisely to
the extent of the working surface, as is shown in FIG. 4 (note
misalignment amount X between each interior marker band M carried
by shaft S and working surface W of balloon 12, which also
typically includes a radiopaque tip P at the distal end). Even upon
exercising great care to position the markers properly on the
underlying shaft in alignment with anticipated boundaries of the
working surface when the balloon is inflated, there remains a
tendency for mismatch due to several possible factors. One such
factor may be the tolerance stack-ups arising as a consequence of
the affixation of the balloon to the distal end of the catheter
shaft. The balloon also has a tendency to grow in the longitudinal
direction when inflated, especially with large and particularly
long balloons. Another factor is the tendency of the portion of the
catheter shaft within the balloon to bend or flex during inflation.
This may lead to misalignment between radiopaque markers fixed to
the shaft and the working surface.
[0008] Whatever the cause, the resulting misalignment may prevent
the clinician from accurately identifying the location of the
working surface of the balloon during an interventional procedure.
This may lead to a geographic misplacement, or "miss," of the
intended contact between the target area T and the working surface
W of the balloon 12 (see FIG. 2). It is especially desirable to
avoid such an outcome when the balloon is designed to deliver a
payload (such as a drug, stent, or both) or a working element to a
specified location within the vasculature, since a miss may prolong
the procedure (such as, for example, by requiring redeployment of
the balloon 12 or the use of another balloon catheter in the case
of a drug coated balloon).
[0009] Upon deflation, the balloon may also be subject to a
phenomenon known as "pancaking." In this condition, the balloon 12
folds down upon itself to a flattened state, as shown in FIG. 5.
This situation may cause the balloon to be viewed through
fluoroscopy as perhaps still being in the inflated condition, since
the full width of the balloon may still be perceived. This can give
the clinician the false perception that the balloon remains
inflated, when in fact it is not.
[0010] Accordingly, the need is identified for a balloon for which
the working surface may be identified during an interventional
procedure with enhanced precision.
SUMMARY
[0011] In one aspect of the disclosure, a method of forming a
medical balloon comprises forming a medical balloon having
radiopaque and non-radiopaque portion through co-extrusion. For
example, the forming step may comprise using a rotating die to form
the medical balloon. The forming step may comprise creating a
balloon parison using the rotating die. The forming step may also
optionally comprise and blow molding the balloon parison into the
medical balloon.
[0012] Another aspect of the disclosure relates to a medical
balloon comprising an inflatable body including a radiopaque felt.
The radiopaque felt may be laminated to a wall of the inflatable
body. The balloon may include tapered end sections, and the
radiopaque felt may correspond to the end sections. The balloon may
include a barrel section, and the radiopaque felt may correspond to
the barrel section.
[0013] A related method of forming the medical balloon described
above may comprise applying the radiopaque felt to a tube. The tube
may then be extruded to form a parison, which may then be blow
molded into the balloon. A related method may also comprise
applying the radiopaque felt to a balloon, and then laminating the
felt to the balloon.
[0014] This disclosure also pertains to a method of providing a
medical balloon or a parison for forming a medical balloon with a
radiopaque portion. The method may comprise inserting a mandrel and
a radiopaque material into the medical balloon or the parison, and
expanding the mandrel.
[0015] In one embodiment, the radiopaque material comprises a film
inserted into the parison prior to the inserting of the mandrel.
The method may further include the step of removing the mandrel
after the expanding step. The mandrel may be adapted to deposit the
radiopaque material on an interior surface of the medical balloon
or parison during the expanding step. The mandrel may be partially
flexible. The mandrel may comprise expandable interwoven struts.
The mandrel may comprise a compliant balloon.
[0016] The method may further include the step of blow molding the
parision into the medical balloon after the expanding step. The
method may further include the step of applying a solution
including the radiopaque material to the mandrel prior to the
inserting step. The method may comprise the step of expanding the
parison to form the medical balloon prior to the inserting and
expanding steps.
[0017] The radiopaque material may comprise one or more radiopaque
fibers associated with the mandrel. The step of expanding the
mandrel may be completed to associate the radiopaque fibers with
the parison or the medical balloon. The method may also comprise
attaching the fibers to an interior surface of the parison or the
medical balloon. The attaching may be done using an adhesive.
[0018] The radiopaque material may also comprise a lattice, and the
method may include associating the lattice with the parison or the
medical balloon. The method may comprise inserting the lattice into
the parison or balloon using the mandrel. This may be done after
the mandrel is compressed.
[0019] This disclosure further pertains to an apparatus comprising
the combination of a medical balloon or a parison for forming a
medical balloon and a mandrel including a radiopaque material and
adapted for insertion into and expanding within the medical balloon
or the parison.
[0020] A related method pertains to providing a parison for forming
a medical balloon with a radiopaque portion, comprising inserting a
radiopaque material into the parison, and blow molding the parison.
The radiopaque material may comprise a film, and further including
the step of attaching the film to the parison. The radiopaque
material may comprise a lattice, and the method includes
associating the lattice with the parison or the medical balloon.
The method may also comprise compressing the lattice and then
inserting the lattice into the parison or balloon using the
mandrel.
[0021] This disclosure also relates to a method of providing a
parison for forming a medical balloon with a radiopaque portion.
The method comprises inserting a radiopaque material comprising a
lattice into the parison, and blow molding the parison. The method
may further include the steps of compressing the lattice and
inserting the lattice into the parison or balloon using the
mandrel.
[0022] A related aspect of this disclosure is a method of providing
a medical balloon or a parison for forming the medical balloon with
a radiopaque portion. The method comprises adhering a radiopaque
material to an interior surface of the medical balloon or the
parison. The adhering step may comprise applying an adhesive to an
interior of the medical balloon or the parison, and applying the
radiopaque material to the adhesive. The adhering step may comprise
applying an adhesive including a radiopaque material to the
interior of the balloon or the parison. In any case, the radiopaque
material may comprise a powder.
[0023] Still another aspect of the disclosure relates to a method
of providing a medical balloon or a parison for forming a medical
balloon with a radiopaque portion. The method comprises inserting
an insert including a radiopaque material into a medical balloon or
a parison, and transferring the radiopaque material from the insert
to the medical balloon or the parison. The method may further
include the step of expanding the insert. The radiopaque material
may be applied so as to identify a working surface of the medical
balloon, either by defining the edges of the working surface,
extending along the working surface, or extending along portions of
the balloon other than the working surface.
[0024] This disclosure also pertains to a medical balloon or a
parison for forming a medical balloon and a mandrel including a
lattice comprising a radiopaque material and adapted for insertion
into and expanding within the medical balloon or the parison. The
lattice may include a longitudinal dimension corresponding to a
working surface of the balloon.
[0025] Further, the disclosure relates to a medical balloon or a
parison for forming a medical balloon and a mandrel including a
radiopaque fiber. The mandrel is adapted for insertion into and
expanding within the medical balloon or the parison. The mandrel
may include a plurality of radially arranged radiopaque fibers.
[0026] Yet another aspect of the disclosure relates to a medical
balloon comprising an adhesive along an inner lumen and a
radiopaque material connected to the balloon by the adhesive. The
radiopaque material may be selected from the group consisting of a
lattice, a fiber, a powder, and any combination thereof. A mandrel
may be provided for carrying the radiopaque material. The adhesive
may comprise a radiopaque adhesive.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0027] FIGS. 1-9 are illustrative of the background of the
invention;
[0028] FIG. 10 illustrates a first embodiment according to the
disclosure;
[0029] FIGS. 11-11a and 12-12a show a manufacturing technique for
forming the FIG. 10 embodiment;
[0030] FIGS. 13 and 14 further shown manufacturing techniques;
[0031] FIG. 15 illustrates a further embodiment according to the
disclosure;
[0032] FIGS. 16 and 17 illustrate another embodiment according to
the disclosure;
[0033] FIGS. 18-21 show still further embodiments;
[0034] FIGS. 22 and 22a are cross-sectional side and end views of
another embodiment;
[0035] FIG. 23 is a side view of a balloon catheter formed
according to one aspect of the disclosure;
[0036] FIGS. 24 and 25 show a further embodiment;
[0037] FIGS. 26-35 show still further embodiments;
[0038] FIGS. 36 to 44 are photographic images illustrating various
embodiments.
MODES FOR CARRYING OUT THE INVENTION
[0039] The description provided below and in regard to the figures
applies to all embodiments unless noted otherwise, and features
common to each embodiment are similarly shown and numbered.
[0040] Provided is a catheter 10 having a distal portion 11 with a
balloon 12 mounted on a catheter tube 14. Referring to FIGS. 6, 7,
and 8, the balloon 12 has an intermediate section 16, or "barrel,"
and end sections 18, 20. In one embodiment, the end sections 18, 20
reduce in diameter to join the intermediate section 16 to the
catheter tube 14 (and thus sections 18, 20 are generally termed
cones or cone sections). The balloon 12 is sealed at balloon ends
(proximal end 15a and distal end 15b) on the cone sections 18, 20
to allow the inflation of the balloon 12 via one or more inflation
lumens 17 extending within catheter tube 14 and communicating with
the interior of the balloon 12.
[0041] The catheter tube 14 also includes an elongated, tubular
shaft 24 forming a guidewire lumen 23 that directs the guidewire 26
through the catheter 10, and along the distal end of which the
balloon 12 may be located. As illustrated in FIG. 8, this guidewire
26 may extend through the proximal end of the catheter 10 and a
first port 25 of a connector 27 into the lumen 23 to achieve an
"over the wire" (OTW) arrangement, but could also be provided in a
"rapid exchange" (RX) configuration, in which the guidewire 26
exits a lateral opening 14a closer to the distal end (see FIG. 9)
or else is fed through the tip at a passage distally of the balloon
12 ("short" RX; not shown). A second port 29 may also be associated
with catheter 10, such as by way of connector 27, for introducing a
fluid (e.g., saline, a contrast agent, or both) into the interior
compartment of the balloon 12 via the inflation lumen 17.
[0042] Balloon 12 may include a single or multi-layered balloon
wall 28 forming the interior for receiving the inflation fluid. The
balloon 12 may be a non-compliant balloon having a balloon wall 28
that maintains its size and shape in one or more directions when
the balloon is inflated. Examples of non-compliant balloons may be
found in U.S. Pat. No. 6,746,425 and Publication Nos. US
2006/0085022, US 2006/0085023 and US 2006/0085024, the disclosures
of which are hereby incorporated herein by reference. The balloon
12 in such case also has a pre-determined surface area that remains
constant during and after inflation, also has a pre-determined
length and pre-determined diameter that each, or together, remain
constant during and after inflation. However, the balloon 12 could
be semi-compliant or compliant instead, depending on the particular
use.
[0043] In order to provide for enhanced locatability during an
interventional procedure, the balloon 12 may have a modified
portion having a radiopaque quality. In one embodiment, this
radiopaque quality is provided in a manner that allows for a
clinician to differentiate, with relative ease and high precision,
one portion of the balloon 12 from another (such as, but not
limited to, the barrel section 16 including the working surface W
from the cone sections 18, 20). This helps the clinician ensure the
accurate positioning of the balloon 12 and, in particular, a
portion of or the entire working surface W, at a specified
treatment location, which may be especially desirable in the
delivery of drugs via the balloon working surface W, as outlined in
more detail in the following description.
[0044] In one embodiment, and with initial reference to FIG. 10,
the radiopaque quality is achieved by providing one or more at
least partially radiopaque markings 30. The marking or markings 30
may be provided along the balloon 12 to create a defined portion as
the working surface W, as contrasted with the full length L of the
balloon. For example, a marking 30 extend along the balloon 12 in a
longitudinal direction along the barrel section 16 and over the
entire circumference of the working surface W. Alternatively, the
marking 30 may extend over only a portion of the working surface W,
or may extend over only a different part of the balloon 12 (such as
the cone sections 18, 20), as outlined further in the following
description.
[0045] This marking 30 may be provided during a process used to
form the balloon 12 having the desired shape created by a
multi-layered wall 28. In particular, a first tube 50 comprising a
thin layer of material (such as a polymer), may be inserted within
a second tube 52, to form a parison 54, as shown in FIGS. 11
(perspective view) and 11a (cross-section). The second tube 52 may
also comprise a compatible polymeric material, but could also be
formed of a different material (such as metal, including possibly a
film). The second tube 52 includes the one or more radiopaque
markings 30, which may correspond in length to the barrel section
16 of the finished balloon, as shown in FIG. 11 (but the second
tube could extend the entire length of the balloon 12, as discussed
below and illustrated by inner tube 62 in FIG. 18). The first,
inner tube 50 may then be expanded to form a multi-layered balloon
12 (FIG. 12), with the second, outer tube 52 thus forming a
radiopaque outer sleeve, as shown in the cross-sectional view of
FIG. 12a.
[0046] Turning to FIG. 13, it can be understood that this
processing may be achieved using a blow mold 54 having separable
portions forming a mold cavity 56 corresponding in shape to the
desired shape of the balloon. The outer tube 52 may be
pre-positioned in the mold cavity 56, including possibly within a
correspondingly shaped recess formed along one or more of the
interior surfaces of the mold 55. The inner tube 50 may then be
expanded using heat and pressure to form the balloon 12 with the
desired shape, and having the outer tube 52 intimately bonded to
it.
[0047] FIG. 14 shows that, instead of a single tube 52, two spaced
tubes, such as radiopaque collars 52a, 52b, may be provided on the
inner tube 50 in order to provide spaced markings 30 on the
finished balloon 12 (see FIG. 19). Like tube 52, these collars 52a,
52b may be pre-positioned in the mold cavity 56 so as to receive
the inner tube 50 when inserted. As noted above for tube 52, the
collars 52, 52b may be comprised of a thin flexible, material
(e.g., a polymer, such as nylon) compatible with the material
(e.g., a polymer, such as nylon) of the adjacent layer formed by
tube 50, but could also be made of different materials, such as one
or more metal foils. Upon expanding the inner tube 50, the collars
52a, 52b are intimately bonded to form a balloon 12 with spaced,
radial markers, which as the result of the positioning at
pre-determined locations in the mold cavity 56 may align precisely
with the edges of the working surface W.
[0048] The markings 30 may be provided on the tube 52 (or tubes
52a, 52b) in various ways. For example, the markings 30 may be
provided by applying a radiopaque material to the tube 52 at the
desired location in any shape, pattern or form (including possibly
alphanumeric characters to provide information that can be
perceived under fluoroscopy, such as a length, diameter, logo,
trademark, rated burst pressure, or balloon type). This may be done
by inking, spraying, printing, or painting the radiopaque material
in fluid form on the surface of the tube 52 (possibly with the
application of a mask or the like, in which case the techniques of
dipping or rolling in the radiopaque material to form the desired
coating could be used). Alternatively, the marking 30 may be
embedded in the tube 52, including for example by providing it as
part of a film or a felt, or in a bonding agent or adhesive used to
bond multiple layers together to form the tube 52 (see, e.g., U.S.
Patent Application Publication No. 2011/0160661, the disclosure of
which is incorporated herein by reference). The marking 30 may be
provided during the process of fabricating the tube 52, such as for
example during a co-extrusion process. Examples of such techniques
are described in international application PCT/US13/29974, which is
incorporated herein by reference.
[0049] As perhaps best understood with reference to FIGS. 15 and
16, the mold cavity may be adapted to form the balloon 12 with the
desired shape and appearance, and could also be adapted to form
shoulders 12a on the balloon 12 once blown. These shoulders 12a may
help to retain the outer tube 52 providing the modified portion of
the balloon 12 against movement in the longitudinal direction, and
thus help to ensure that it remains positioned at the desired
location (again, in one embodiment, aligned with the full extent of
the working surface W). Additionally or alternatively, as shown in
FIG. 17, the inner surface of the outer tube 52 may be adapted for
frictionally engaging the outer surface of the tube 50, such as by
providing a roughened or textured surface 58.
[0050] Additionally or alternatively, an adhesive may be used to
improve the bond between the tubes 50, 52. This adhesive may be
provided on either tube prior to blow molding. The adhesive may
also optionally be provided with a radiopacifier in order to
enhance the radiopaque quality of the balloon 12 (see, e.g., U.S.
Patent Application Publication No. 2011/0160661).
[0051] Another embodiment involves forming the balloon 12 with a
modified portion by blow molding a multi-layered parison, wherein
at least one of the layers of the parison comprises a radiopaque
material. Thus, for example, a parison 60 in this embodiment may
include an inner layer comprising a radiopaque film 62, and an
outer layer 64 comprising a traditional film that is not made
radiopaque by an additive. The blow molding process expands the
parison 60 to thus form a balloon 12 having a radiopaque quality
corresponding to the length of the inner layer including
radiopacifier, which may be the full length L of the balloon
12.
[0052] A balloon may be formed by stretching a polymer tube of
constant wall thickness to a desired or preferred shape wherein the
barrel portion is larger in diameter than other portions intended
to be the cones or shoulders of the formed balloon. Such a process
may be achieved by placing a balloon parison in to a mold and
altering the physical surroundings, such as increasing temperature
and/or applying pressure, such as through increased fluid (gas or
liquid) pressure, to allow the parison to take the shape of the
surrounding mold.
[0053] Balloons 12 that incorporate coatings comprising drugs to be
applied to the vasculature may also benefit from the
above-referenced embodiments. For example, as shown in FIG. 19, a
balloon 12 including a defined working surface W, such as by
providing radiopaque markings 30 at the transitions between the
barrel section 16 and cone sections 18, 20, may include a portion
coated with such a drug D, such as one designed for achieving a
desired therapeutic effect when applied to the interior of the
vessel. The radiopaque marking 30 may also correspond to the
location of the drug D on the balloon 12, such as along the entire
working surface W or only a portion of it. The drug D may be
applied to the inflated balloon as part of the manufacturing
process, and prior to folding for insertion in the vasculature. The
clinician may thus with the benefit of a fluoroscope determine the
precise positioning of the working surface W prior to inflating the
balloon 12 in the vasculature to deliver the drug D to the desired
location and provide the desired treatment regimen.
[0054] The markings 30 may also be provided as one or more
longitudinal strips 66 that do not extend along the entire
circumference of the balloon 12, as shown in FIGS. 20 and 21. This
may be achieved by providing one or both of the layers 62, 64, or
the tube 52, with radiopaque material corresponding to the strips
66, such as by a co-extrusion process. Additional details are
provided in PCT/US13/29959, PCT/US13/29967, PCT/EP13/54748, and
PCT/US13/29977, the disclosures of each of which are incorporated
herein by reference. The presence of plural spaced markings 30 in
this manner may also help to distinguish between the inflated
condition (in which the markings are spaced), and the properly
deflated condition, as the markings would be closer to each other
when the balloon is folded.
[0055] In another embodiment, the blow molding operation may be
arranged to create a balloon 12 with a different type of modified
layer. For example, in FIG. 22, an insert 52 may be provided with a
functional modification, such as an outer surface that is textured
or etched, and associated with an inner tube 50. The insert 52
could be made partially or fully radiopaque if desired (see, e.g.,
FIG. 10), but such is considered optional. In one embodiment, a
multi-layered insert 52 may be provided with an outer radiopaque
layer 51a and an inner support layer 51b that is not enhanced with
a radiopacifier and exposed by the openings 53 formed by etchings
in the outer layer (see FIG. 22a). This may create a particular
pattern under fluoroscopy, which may allow for the detection of the
locations on the balloon 12 where a drug is present (either on the
etched portions or the unetched portions, as desired, which again
may correspond to the working surface W).
[0056] In any case, on blow molding the resulting parison 54 into a
corresponding mold 55 (see FIGS. 13 and 14), a balloon 12 may be
formed having an etched or textured outer surface layer 28a of the
balloon wall 28. This layer 28a may extend along the entire working
surface W, as shown in FIG. 23, or any portion of it. In the case
of etching, texturing, or other surface features, the material
forming the insert 52 should have a sufficiently high melt flow
index such that the features are not caused to disappear as the
result of the heat and pressure created during the blow molding
process.
[0057] Another example for creating a balloon 12 with a modified
layer is to provide an insert 52 with one or more openings. For
example, as shown in FIG. 24, the insert 52 may be provided as a
reticulated or fenestrated body, such as a mesh, screen or lattice
having a plurality of crossing members 57 forming openings 53. The
body 52 may be tubular in form, as shown, and could comprise more
than one piece or part (similar to collars 52a, 52b). As above, the
material forming the insert 52 should have a sufficiently high melt
flow index such that the features are not caused to disappear as
the result of the heat and pressure created during the blow molding
process.
[0058] When arranged to form a parsion 54 and blow molded together,
the insert 52 bonds to an inner tube 50 and forms an outer layer of
the finished balloon 12. In the case of an insert 52 as shown, the
openings 53 expose the balloon wall 28, which may be adapted to
form the modified layer (such as by being radiopaque). The body 52
may extend along the entire working surface W, and may optionally
be fully or partially radiopaque. Alternatively, the body 52 may be
provided with a coating, such as in the form of a drug or an agent
providing enhanced lubricity.
[0059] It is also possible to modify the mold 55 to provide a
surface treatment on the finished balloon 12. For example, as shown
in FIG. 25, the inner surfaces of the mold cavity 56 may be
provided with a textured pattern 56a, such as by etching,
engraving, or the like, so as to form inwardly directed
projections. This includes along the portions corresponding to the
working surface W of the balloon 12 (e.g., the barrel section).
When a parison 54 (which may be a single layer of material), is
then expanded in the mold cavity 56 (FIG. 26), the surface of the
resulting balloon 12 is provided with a corresponding pattern in
the form of an impression of the pattern in the mold 55. In other
words, the projections forming the pattern 56a in the mold form
depressions in the outer surface of the balloon wall 28.
[0060] An option in this embodiment is to deposit a material within
the mold cavity 56 to partially or completely fill any spaces or
gaps formed in the pattern 56a, such as for example a radiopacifier
59. As shown in FIGS. 27 and 28, the balloon 12 resulting from blow
molding using a mold 55 with this type of pattern 56a with a filler
would thus have a surface layer modified to including the selected
filler material (which in the case of a radiopacifier 59 would make
the surface partially radiopaque, as shown by the darkened portions
of the balloon wall 28 in FIG. 28). The depositing of the material
within the mold 55 may be done by injection through an internal
passageway opening within the cavity 56, either before or during
the molding process, including possibly by spraying the filler
material within the mold cavity 56 (such as when the mating
portions forming the mold 55 are separated to expose the surface
pattern 56a).
[0061] The balloon catheter 10 may be formed by forming a balloon
parison with discrete radiopaque segments introduced by
coextrusion. The coextrusion may involve the use of a rotating die
(see, e.g. U.S. Patent Application Publication No. 2003/0100869,
the disclosure of which is incorporated herein by reference) to
form discrete sections within the tube of one or more materials,
such as a radiopaque material. The parison may then be blow molded
to form the balloon, with the radiopaque material then embedded in
the walls thereof (such as between the ends of the working surface,
along the entire working surface, along one or both of the end
sections or cones (see, e.g., FIGS. 19-21), and in all cases either
partly or fully providing coverage of the respective surfaces).
[0062] The markings 30 may further by introduced into the balloon
12 through application of a radiopaque felt. For example,
attachment of a radiopaque felt 72 to a balloon parison 70 (FIG.
29) may allow for precise identification of each region of the
balloon (such as by indicating the portion comprising the working
surface relative to other portions). As shown in FIG. 30, the
radiopaque felt 72 may also be applied to the exterior of a formed
balloon 12, optionally followed by a secondary process, such as
lamination (note film 74), to thereby secure the felt in position.
Alternatively, as shown in FIG. 31, the radiopaque felt 72 may be
applied over an extruded tube 76, followed by a secondary extrusion
step, e.g. wire coating, to secure the felt. In such a case, the
dual-layer tubing may then be formed into a balloon 12 by steps
such as blow-molding or other similar processes known in the
art.
[0063] As shown in FIG. 32, radiopaque material may also be applied
to an inner lumen of a balloon parison 80 or fully-formed balloon
12 through the use of an expanding mandrel 82. For example, the
mandrel 82 may comprise a rigid portion 82a with a distally fixed
expandable portion 82b that can have both a retracted configuration
and an expanded configuration. The distal section may be sized to
efface the inner lumen of the balloon parison 80 when in the
expanded configuration, yet still able to pass through both
proximal and distal ends thereof in the retracted configuration.
The distal end of the mandrel 82 should be constructed of a
material that can withstand gas and/or liquid pressure, such as a
compliant balloon.
[0064] The mandrel 82 may also be comprised of opposed and/or
interwoven struts arranged in a manner such that expansion may be
achieved during contraction (e.g. a helically wound braid, such as
a biaxial braid, wherein reduced angle between the warp and weft at
crossing points in turn reduces radial distance between opposing
sides) or as opposing struts connected in the middle and at each
end are affected by a pivoting joint (e.g. a pantographic
mechanism).
[0065] The radiopaque material or a portion thereof may also be
introduced to the balloon parison prior to molding. For instance, a
radiopaque material, such as a film or a felt, that comprises a
radiopaque material (e.g. tungsten, barium, tantalum, gold,
platinum) with the addition of polymers to provide a structural
matrix, as well as optionally stabilizers and/or plasticizers, can
be applied to the parison prior to molding. Rolling or folding the
radiopaque material allows the material to efface an inner lumen of
the parison as it expands following insertion and up to or during a
molding step. The addition of an adhesive applied to the exterior
of the radiopaque material prior to insertion into the parison may
further enhance in adhering the material to the balloon catheter
lumen. Those skilled in the art will appreciate that expansion of
the distal tip of the mandrel discussed herein will further secure
the radiopaque material.
[0066] The markings 30 may also be introduced to the balloon 12 as
a solution. For example, as indicated in FIG. 33, a solution
comprising radiopaque material 86 in suspension optionally aided by
stabilizers, may be applied to the outer lumen of the expandable
mandrel 82. The distal portion of the expandable mandrel can then
be inserted into a balloon parison (e.g., the example provided in
FIG. 32) with the mandrel in a retracted configuration (e.g.,
deflated, in the case of a balloon). The mandrel 82 can then move
to the expanded configuration to efface the parison lumen and
similarly deposit the solution on the lumen surface, and the
parison then used to form the balloon 12. Alternatively, a
radiopaque solution may be applied by the expandable mandrel after
the balloon is fully formed.
[0067] The markings 30 may also comprise radiopaque fibers. Fibers
comprised of a radiopaque material, such as tungsten, tantalum,
platinum or similar can be achieved through a polymer matrix and
optionally formed through an extrusion process. Fibers can then be
introduced to the balloon through the use of the expandable mandrel
80 as discussed herein. The mandrel 82 can be sized in such a
manner that it can be inserted in through the proximal and distal
ends of the balloon parison 80 in the retracted configuration and
so that it can fully efface the inner lumen of the parison in the
expanded configuration. As shown in FIG. 34, fibers 88 can be
arranged in a radial configuration around the mandrel 82 prior to
insertion into the parison 80. Following expansion of the mandrel
82, the fibers may be deposited on the inner lumen of the parison
80, after which the mandrel can be reduced to the retracted
configuration and withdrawn. Fibers may be adhered to the inner
lumen through the use of an adhesive, and optionally later cured
during a secondary process, such as exposure to UV light, heat, or
flash-off solvents.
[0068] The marking 30 may also be introduced to the balloon 12 as a
lattice or matrix 90 of radiopaque material, as shown in FIG. 35.
Flexible polymers embedded with radiopaque material may be formed
by extrusion, optionally followed by cutting to form the lattice
and thus reduce the surface area for increased flexibility. The
outer diameter of the lattice or matrix 90 may be sized to efface
the inner lumen of a balloon parison 80 and the length of the
lattice selected to correspond to the balloon barrel portion or to
the cone/shoulder portions. The lattice may be compressed to a
smaller diameter to allow for insertion in the parison 80 through
the open ends corresponding to the proximal or distal cone regions.
An adhesive may further be introduced to assist in anchoring to the
inner lumen.
[0069] The marking 30 may also be applied to the balloon 12 as a
powder. Adhesion of a radiopaque powder may be achieved through
selective application of an adhesive to the inner lumen of a
parison for forming the balloon. An insert (such as a hypo-tube)
may be inserted through one end of a parison, and which insert may
be provided with an applicator (e.g., a swab or sponge at the
distal end, which may be expandable) to be in communication with
the inner lumen. The swab or sponge may then selectively be used to
efface the cone portion of the balloon, followed by administration
of an adhesive through the insert. Thereby, adhesive is selectively
applied to the inner lumen by the sponge. The balloon may then be
optionally moved or rotated to enhance even distribution. The
insert (hypo-tube) may then be retracted and repeated through the
opposing end of the balloon as needed. Following application of the
adhesive, radiopaque material (which may be in the form of a
powder) may be applied to the inner lumen, and then optionally
shaken or rotated. Powder not adhered to the lumen may then be
removed prior to introduction of the catheter shaft. Alternatively,
a powder may be combined with the adhesive and then applied to the
inner lumen through techniques such as brush coating, spray coating
or flush and fill.
Example
[0070] Radiopaque (RO) powder was weighed in a 20 ml glass vial
which then UV light curing adhesive, 208-CTH-F Dymax (Torrington,
Conn.) was also added. The percentages of the components were
totaled to one hundred percent (100%). The RO coating mixture was
thoroughly mixed and transferred to a 3cc polypropylene syringe
which was then placed onto a syringe pump for coating. Attached a
nozzle (i.e. EFD needle tip) to the 3cc syringe and the nozzle was
inserted into the lumen diameter of the balloon neck for luminal
coating, only the shoulders of the balloon were coated. The
infusing rate was set at 0.5 ml/minute. Once the RO coating mixture
was pumped up to the shoulder-barrel transition point, it was
withdrawn back into the syringe to complete the coating cycle. The
coated section was cured using Dymax BlueWave 200 equipment. The
coating steps were repeated for the other neck of the balloon.
[0071] Below are the X-ray images of different RO materials were
used. Below are the X-ray images of different RO materials were
used.
TABLE-US-00001 Description X-ray (65 Kv) Comments Evaluated 20, 30,
See FIG. 25 wt % RO solution 35 wt % BiCO3 36 and 37 yields
flexible loadings in 208- coating. 30% and CTH-F Dymax. 35 wt %
yield harder coating. Optimal cure time for 25% is 4 seconds.
Higher loadings yield better X-ray visibility and thicker coating.
Evaluated 50 and See FIG. 38 50 wt % Ta solution 55 wt % Ta
loadings and 39 yields flexible in 208-CTH-F coating. 55 wt %
Dymax. Ta coating yields harder coating. Optimal cure time is 6
seconds. Evaluated See FIG. 40, 30 wt %/10 wt % combination of 41
and 42 yields very flexible Ta and BiCO3 coating. Other for more
flexibible formulations yield coating with harder coating. similar
or better Optimal cure time X-ray visibility. is between 6-12
Formulations: seconds. 30 wt % Ta/10 wt % Higher loading BiCO3 40
wt % Ta/ yield better X-ray 10 wt % BiCO3 visibility and 30 wt %
Ta/15 wt % thicker coating. BiCO3 20 wt % Ta/20 wt % BiCO3
Re-evaluated the See FIG. 43 Flexible coating, not curing issue of
completely cured. Tungsten loaded Three different formulation. This
cure times (6, 12, 18 was found in seconds) were evaluated.
previous experiments Good X-ray visibility. in page 31. Evaluated
3M MG250 See FIG. 44 Was able to cure adhesive for tungsten (2
.times. 9 sec) with 3M loaded formulation adhesive, flexible
coating, good X-ray visibility
[0072] Examples of radiopaque materials include, but are not
limited to, finely divided tungsten, tantalum, bismuth, bismuth
trioxide, bismuth oxychloride, bismuth subcarbonate, other bismuth
compounds, barium sulfate, tin, silver, silver compounds, rare
earth oxides, and many other substances commonly used for X-ray
absorption. The polymer used for making a film, possible with a
radiopaque material, may be any polymeric material which can be
loaded with radiopacifier and formed into a sufficiently thin film.
Examples of polymers include thermoplastic and thermoset polymers.
Some examples of thermoplastic polymers include, but are not
limited to, polyurethanes, polyamides (nylon 11, nylon 12),
polyether-polyamide copolymers such as PEBAX, polyethylene
terephthalate or other polyesters, polyvinyl acetate, polyvinyl
chloride, and many other thermoplastic materials useful for making
films. Some examples of thermoset polymers include, but are not
limited to, crosslinked polyurethanes, polyureas, epoxies,
acrylics, silicones, and many other thermoset materials that can be
formed into thin structures, including films. Any adjacent
structures to be bonded, such as tubes 50, 52 or layers 62, 64, may
be formed of compatible materials, which may avoid additional
processing or the inclusion of a compatibilizer, tie layer or the
like.
[0073] While the disclosure presents certain embodiments to
illustrate the inventive concepts, numerous modifications,
alterations, and changes to the described embodiments are possible
without departing from the sphere and scope of the present
invention, as defined in the appended claims. For example, any
ranges and numerical values provided in the various embodiments are
subject to variation due to tolerances, due to variations in
environmental factors and material quality, and due to
modifications of the structure and shape of the balloon, and thus
can be considered to be approximate and the term "approximately"
means that the relevant value can, at minimum, vary because of such
factors. Accordingly, it is intended that the disclosure not be
limited to the described embodiments, but that it has the full
scope defined by the language of the following claims, and
equivalents thereof.
* * * * *