U.S. patent application number 12/761177 was filed with the patent office on 2010-08-05 for polymer shrink tubes and novel uses therefor.
Invention is credited to Benjamin M. Trapp.
Application Number | 20100198193 12/761177 |
Document ID | / |
Family ID | 36782547 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100198193 |
Kind Code |
A1 |
Trapp; Benjamin M. |
August 5, 2010 |
POLYMER SHRINK TUBES AND NOVEL USES THEREFOR
Abstract
Novel polymer shrink tubes, such as fluoropolymer shrink tubes
and novel uses thereof. The polymer shrink tubes include at least
one three-dimensional pattern formed along at least a portion of
the inner surface of the tube. The polymer shrink tubes can be used
for, for example, embossing a pattern into a polymer tube. Further
use includes, for example, forming a catheter with at least one
channel located in the catheter wall.
Inventors: |
Trapp; Benjamin M.;
(Flagstaff, AZ) |
Correspondence
Address: |
Kevin J. Boland, Esquire;W. L. Gore & Associates, Inc.
551 Paper Mill Road
Newark
DE
19714-9206
US
|
Family ID: |
36782547 |
Appl. No.: |
12/761177 |
Filed: |
April 15, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12191516 |
Aug 14, 2008 |
7736571 |
|
|
12761177 |
|
|
|
|
11073053 |
Mar 4, 2005 |
|
|
|
12191516 |
|
|
|
|
Current U.S.
Class: |
604/524 ;
604/103.09 |
Current CPC
Class: |
Y10T 428/139 20150115;
A61L 29/041 20130101; A61L 29/041 20130101; A61L 29/04 20130101;
C08L 27/12 20130101 |
Class at
Publication: |
604/524 ;
604/103.09 |
International
Class: |
A61M 25/00 20060101
A61M025/00; A61M 25/10 20060101 A61M025/10 |
Claims
1. A catheter comprising: a fluoropolymer tube having a proximal
end, a distal end, an inner surface defining a longitudinally
extending, generally central lumen and an outer surface; an outer
polymer tube having a proximal end, a distal end, an inner surface
and an outer surface, wherein the inner surface of the outer
polymer tube is positioned over the outer surface of the
fluoropolymer tube; wherein at least one channel is located in the
outer polymer tube, the at least one channel measuring about 7 by
about 15 mils and extending for at least a portion of the length of
the catheter; and polymer film covering at least a portion of the
length of the at least one channel, thus defining at least one
longitudinally extending lumen in the catheter.
2. The catheter of claim 1, further comprising a reinforcing
material in contact with the outer polymer tube.
3. The catheter of claim 2, wherein the reinforcing material
comprises metal.
4. The catheter of claim 3, wherein the metal comprises a material
selected from the group consisting of stainless steel and
nitinol.
5. The catheter of claim 3, wherein the metal is a coil
construction.
6. The catheter of claim 2, wherein the reinforcing material is
embedded by the outer polymer tube.
7. The catheter of claim 1, wherein the catheter has an outer
diameter of about 9 French or less.
8. The catheter of claim 7, wherein the catheter has an outer
diameter of about 8 French or less.
9. The catheter of claim 1, wherein the fluoropolymer tube
comprises a material selected from the group consisting of
polytetrafluoroethylene and fluorinated ethylene propylene.
10. The catheter of claim 9, wherein the fluoropolymer tube
comprises polytetrafluoroethylene.
11. The catheter of claim 1, wherein the at least one channel
extends from the proximal end to the distal end of the outer
polymer tube.
12. The catheter of claim 11, wherein an inflatable member is
located at the distal end of the catheter and the at least one
channel is in fluid communication with the interior of the
inflatable member.
13. The catheter of claim 12, wherein the outer polymer tube
comprises at least a second channel.
14. The catheter of claim 6, wherein the fluoropolymer tube
comprises polytetrafluoroethylene, the outer polymer tube comprises
polyether block amide, the polymer film comprises expanded
polytetrafluoroethylene, and the reinforcing material comprises
stainless steel coil.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of commonly owned and
copending application Ser. No. 12/191,516, filed Aug. 14, 2008,
which is a divisional of commonly owned and copending application
Ser. No. 11/073,053, filed Mar. 4, 2005, and both prior
applications are incorporated by reference herein in their
entirety.
FIELD OF THE INVENTION
[0002] This invention relates to polymer shrink tubing. Such shrink
tubing can be used for, among other things, the manufacture of
catheters.
DESCRIPTION OF RELATED ART
[0003] The use of delivery catheters to provide various treatments
to a patient is well known. Such delivery catheters have a variety
of well-known uses such as, for example, PTA and PTCA treatment,
stent delivery, etc. Many delivery catheters are guided to the
treatment location through a previously placed guide catheter.
Moreover, it is also known to advance diagnostic catheters,
angiographic catheters, and steerable catheters to a treatment
location through a previously placed guide catheter.
[0004] The guide catheter will typically have a centrally located
lumen, with the delivery catheter passed through the centrally
located lumen to the treatment site. In view of this, it is common
for the inner surface of the guide catheter that defines the
centrally located lumen to be comprised of a low friction material,
such as polytetrafluoroethylene (PTFE). Moreover, to provide
structural support guide catheters usually are metal reinforced
using, for example, a metal braid or coil wrapped about the low
friction material. It is not uncommon for the metal reinforcement
to be embedded by an outer polymer material that defines the outer
wall portion of the guide catheter.
[0005] Recently, it has been suggested to use guide type catheters
for certain stroke therapies, wherein the guide catheter is
delivered, for example, to a patient's carotid artery. Various
treatment devices, such as delivery catheters, balloon-on-a-wire
devices, thrombectomy removal devices, etc., can be guided to the
treatment site through one or more lumens provided in the guide
catheter. Moreover, such guide catheters can include an inflatable
member at the distal end thereof to occlude blood flow in the
selected carotid artery.
[0006] Examples of such stroke therapy catheter constructions are
illustrated in, for example, commonly owned U.S. Pat. Nos.
6,206,868; 6,423,032; 6,540,712; and 6,295,989.
[0007] Such catheter constructions can present manufacturing
challenges. For example, catheter constructions as shown, for
example, in commonly owned U.S. Patent Application Publication Nos.
2003/0040704A1; 2003/0040694A1; and 2003/0040705A1, can include,
for example, at least an inflation lumen in the catheter wall,
which inflation lumen will be in communication with the inflatable
member at the distal end of the catheter. Further, the catheter
wall can be a polymer material that embeds a metal reinforcement.
Moreover, a PTFE inner liner material can define a centrally
located lumen.
[0008] Providing one or more lumens in the catheter wall of such
constructions is extremely difficult. One method of providing
lumens in the catheter wall is described in commonly owned and
copending U.S. Patent Application Publication No. 2004/0193139,
published Sep. 30, 2004, which discloses a polymer film wrapping
process to produce such catheters. The catheter can be formed by
placing a thin-walled PTFE liner tube over a mandrel. A wire
support structure (e.g., braid, ribbon, coil, etc.) can then be
placed over the thin-walled tube. Over the wire support structure
is placed a thermoplastic material that is caused to embed the wire
support structure. As taught in this commonly owned patent
application, at least one lumen, or channel, in the catheter wall
can be formed by a laser cut into a thermoplastic material defining
the outer catheter wall. Thereafter, a polymer film is applied to
(e.g., wrapped about) the catheter wall to close the channel and
form the longitudinally extending lumen in the catheter body.
Another method of forming lumens in the catheter wall includes, for
example, placing a small, hollow tube, such as polyimide tube,
adjacent the wire support structure and then embedding the wire
support structure and small tube into the thermoplastic
material.
[0009] The present invention provides, among other things, unique
methods of forming such catheter constructions that overcome the
problems discussed above.
SUMMARY OF THE INVENTION
[0010] The invention relates to polymer shrink tubing and novel
uses therefore. One aspect of the invention is a tube comprising a
fluoropolymer shrink tube having an inner surface and at least one
three-dimensional pattern formed along at least a portion of the
inner surface of the tube. In an aspect of the invention, the
three-dimensional pattern comprises at least one rib formed along
the inner surface. The at least one rib can be longitudinally
extending, spirally extending, etc.
[0011] In a further aspect of the invention, the invention includes
a tube comprising a polymer shrink tube having an inner surface and
at least one rib formed along the inner surface, the rib extending
from the inner surface and having a height of about 0.5 mils or
less, more preferably less than about 0.2 mm.
[0012] A further aspect of the invention includes a catheter
comprising an inner liner comprising fluoropolymer (e.g., PTFE)
tubing. Preferably the fluoropolymer tube is an extruded PTFE tube.
The tube having a proximal end, a distal end, an inner surface and
an outer surface; an outer polymer tube having a proximal end, a
distal end, an inner surface and an outer surface, wherein the
inner surface of the outer polymer tube is positioned over the
outer surface of the fluoropolymer tube; wherein at least one
channel is formed in the outer polymer tube, the at least one
channel preferably measuring about 7 by about 15 mils
(0.007''.times.0.015'') and extending for at least a portion and
preferably a majority of the length of the catheter; and polymer
film covering at least a portion and preferably a majority of the
length of the at least one channel, thus forming a lumen in the
outer polymer tube.
[0013] In a still further aspect of the invention, the invention
includes a method of creating an external, embossed pattern on the
exterior of a cylindrical device comprising: providing a polymer
tube having at least one exterior surface; providing a polymer
shrink tube having an inner and an outer surface, the inner surface
having at least one three-dimensional pattern thereon; placing the
polymer shrink tube around the polymer tube; applying sufficient
energy to the shrink tube so as to shrink the shrink tube around
the exterior of the polymer tube while causing at least a portion
of the at least one three-dimensional pattern to become embossed
into the exterior surface of the polymer tube. The applied energy
softens the polymer tube material and shrinks the shrink tube, thus
leading to embossing the pattern into the polymer tube. This method
is particularly suitable for forming catheters such as the guide
catheters discussed above.
DESCRIPTION OF THE DRAWINGS
[0014] The operation of the present invention should become
apparent from the following description when considered in
conjunction with the accompanying drawings in which:
[0015] FIG. 1 shows in partial perspective view a polymer shrink
tube according to the present invention;
[0016] FIG. 2 is a schematic cross-section taken along lines 2-2 of
FIG. 1;
[0017] FIG. 3 is a schematic cross-section of the use of a polymer
shrink tube according to the invention;
[0018] FIG. 4 is a schematic cross-section of a further use of a
polymer shrink tube according to the present invention;
[0019] FIG. 5 is a schematic cross-section of a catheter according
to the present invention; and
[0020] FIG. 6 is a longitudinal cross-section of a catheter
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] A first aspect of the invention is a tube comprising a
fluoropolymer shrink tube having an inner surface and at least one
three-dimensional pattern formed along at least a portion of the
inner surface of the tube. In a further aspect of the invention,
the three-dimensional pattern can comprise at least one rib (such
as at least one longitudinally extending rib) formed along the
inner surface of the tube. Suitable fluoropolymer materials
include, for example, fluorinated ethylene propylene (FEP),
fluoroelastomers such as VITON.RTM. fluoroelastomers (DuPont Dow
Elastomers), ethylene tetrafluoroethylene (ETFE), perfluoroalkoxy
(PFA), and polytetrafluoroethylene (PTFE). The fluoropolymer shrink
tube is shown in partial perspective view in FIG. 1. FIG. 2 is a
cross-section schematic drawing taken along lines 2-2 of FIG. 1. As
shown in the figures, the three-dimensional pattern formed along at
least a portion of the inner surface of the tube 10 is indicated by
1, and in this case, is a longitudinally extending rib which can
extend for essentially the entire length of the tube. Other
three-dimensional patterns are envisioned by the present invention,
such as, for example, spirally extending ribs, as well as a
plurality of three-dimensional patterns, such as two or more
ribs.
[0022] By "shrink tube having at least one three-dimensional
pattern formed along at least a portion of the inner surface of the
tube" it is meant to include longitudinally extending, hollow tubes
having at least one protuberance, recess, or otherwise
three-dimensional pattern, on the inner surface of the tube. The
tube will exhibit some shrinkage of its inner diameter upon
exposure to suitable energies, such as heat. Longitudinal shrinkage
is not a requirement according to the invention, although it may be
desirable. Therefore, "shrink tube" will include a polymer tube
that will exhibit some shrinkage of its inner diameter upon
exposure to suitable energy and may also exhibit some longitudinal
shrinkage upon exposure to suitable energy. It is desirable for the
shrink tube to shrink in a predictable manner such that the
three-dimensional pattern is predictably retained upon exposure to
the suitable energy.
[0023] Polymer shrink tubes can be made by, for example, well-known
extrusion processes. Typically such tubes will be formed having a
first inner diameter. The tube is then expanded to a second inner
diameter (referred to as the "expanded inner diameter"). Upon
application of suitable energy the inner diameter will shrink back
to about the first inner diameter (referred to as the "retracted
inner diameter").
[0024] As stated above, the shrink tubes can comprise, for example,
the fluoropolymer materials listed above. The fluoropolymer shrink
tubes will shrink when heated to an appropriate temperature or
exposed to other suitable energy forms. For example, the following
shrink tubes will shrink at about the listed temperature or
temperature range. VITON.RTM. fluoroelastomer, about 120.degree.
C.; ETFE, about 175.degree. C.; PFA, about 204.degree. C.; FEP,
from about 210 to about 260.degree. C.; PTFE, from about 325 to
about 340.degree. C. A particularly attractive fluoropolymer tube
comprises FEP.
[0025] In a further aspect of the invention, the invention includes
a catheter comprising an inner liner comprising fluoropolymer
(e.g., PTFE) tubing having a proximal end, a distal end, an inner
surface defining a generally centrally located catheter lumen and
an outer surface; an outer polymer tube having a proximal end, a
distal end, an inner surface, and an outer surface; wherein the
inner surface of the outer polymer tube is positioned over the
outer surface of the fluoropolymer tube; wherein further at least
one longitudinally extending channel is formed in the outer polymer
tube, the at least one channel (preferably measuring about 7 by
about 15 mils) extending for at least a portion and preferably a
majority of the length of the catheter; and polymer film covering
at least a portion and preferably a majority of the length of the
at least one channel; thus defining a longitudinally extending
lumen in the catheter wall. Preferably, the catheter is a delivery
catheter having an about 9 French or less outer diameter, even more
preferably an about 8 French or less outer diameter. In an aspect
of the invention the catheter wall has a thickness of about 15 mil
or less, and preferably about 10 mil or less, for at least a
portion of its length, and preferably over substantially its entire
length. The at least one channel can be formed using polymer shrink
tube. In an aspect of the invention the polymer shrink tube has an
expanded inner diameter of about 0.150 inch over substantially the
entire length of the tube. In a further aspect of the invention the
polymer shrink tube has a retracted inner diameter of about 0.100
inch over substantially the entire length of the tube. In a still
further aspect of the invention, the at least one channel can be
formed using fluoropolymer shrink tube, as discussed above. The
fluoropolymer tube can comprise any suitable fluoropolymer as
discussed above and may have an expanded inner diameter of about
0.150 inch over substantially the entire length of the tube and may
also have a retracted inner diameter of about 0.100 inch over
substantially the entire length of the tube. Other polymer shrink
tube may be used, such as olefins, including chlorinated olefins,
polyethylene terephthalate (PET), and polyvinyl chloride (PVC).
[0026] The outer polymer tube can comprise any suitable polymer.
Preferred polymers include thermoplastics such as PEBAX.RTM.
polyether block amides, nylon, urethanes, polyethylene,
polypropylene, FEP, etc. Particularly preferred for the outer
polymer tube is a material comprising PEBAX.RTM. polyether block
amides, such as PEBAX.RTM. 6333.
[0027] It should be understood that although the inner surface of
the outer polymer tube is positioned over the outer surface of the
fluoropolymer tube, there is no requirement that the tube surfaces
directly contact each other. It may be desirable to provide an
adhesive between these materials. Moreover, a reinforcing material
such as a metal (e.g., stainless steel or nitinol) or polymer
support structure such as braiding, coil, stylets, tubing, ribbon,
or what-have-you can be positioned between the tube surfaces to
obtain desired properties. It may be desirable for the outer
polymer tube to at least partially embed any reinforcing material
(e.g. metal braid). Moreover, it may be desirable for the outer
polymer to flow through the reinforcement and bond to the
fluoropolymer tube. In such a case, the fluoropolymer tube outer
surface can be chemically etched to aid in the adhesion between the
outer polymer tube and fluoropolymer tube.
[0028] The polymer film which can cover the at least one channel,
can comprise any suitable polymer film material.
[0029] For example, the film material can be made from a thin tape
of porous expanded polytetrafluoroethylene (ePTFE) that can be
helically wrapped about the exterior of the catheter shaft.
Preferred ePTFE films are generally made as taught by U.S. Pat.
Nos. 3,953,566 and 4,187,390 to Gore. Even more preferred ePTFE
films can be made as taught by U.S. Pat. No. 5,476,589 to Bacino.
Further examples of polymer films include polyethylene (including
ultra-high molecular weight polyethylene), polypropylene,
polyamide, polyethylene terephthalate, fluorinated ethylene
propylene (FEP), perfluoroalkoxy resin, polyurethane, polyester,
polyimide, etc.
[0030] Most preferably, the wrapping is accomplished in two
opposing directions parallel to the length of the outer polymer
tube, resulting in a bias-ply construction. Although helically
wrapping a tape of polymer film is a preferred embodiment, it is
also possible to provide the polymer film as a thin tubular
structure that can coaxially enclose the entire outer polymer tube.
Moreover, it is also possible to provide a strip of thin polymer
tape material that covers the channel and is adhered to the surface
of the outer polymer tube immediately adjacent both sides of the
channel. Suitable wrapping techniques are fully described in, for
example, commonly owned and copending U.S. Patent Application
Publication No. 2004/0193139, published Sep. 30, 2004. As described
in the commonly owned application, the porous polymer tape can
optionally be provided with a thin, non-porous coating. Moreover,
prior to wrapping the polymer tube, it may be desirable to fill the
channel (at least partially or completely) with a material that
will provide structural support to the at least one channel so that
the dimensions of the channel will not be substantially altered by
the film wrapping process. Of course, materials that can be easily
removed from the channel after film wrapping is completed are
preferred and will be apparent to the skilled artisan.
[0031] The polymer tape is most preferably made from a thin porous
expanded PTFE film that has been provided with a porous or
non-porous coating of, or is at least partially imbibed with, a
thermoplastic such as a thermoplastic fluoropolymer, and preferably
EFEP (ethylene tetra fluoro ethylene based copolymer, available
from Daikin America). An example of a suitable wrapping technique
includes using EFEP in combination with ePTFE tape. The tape can
have, for example, a width of about 6 mm and a thickness of about
0.005 mm. The ePTFE film can be provided with a non-porous coating
of EFEP on one or both sides. Moreover, the porosity of the ePTFE
film can be at least partially or substantially completely imbibed
with EFEP. After the coated and/or imbibed film is cut into narrow
tape, the tape can be helically wrapped about the outer polymer
tube comprising PEBAX.RTM. polyether block amide. The wrapped
catheter can then be heated for about 5 minutes in a convection
oven set at about 160.degree. C. to melt-bond the helically wrapped
layers of the film together. Thereafter, the catheter can be
removed from the oven and cooled to room temperature.
[0032] In an alternative embodiment, rather than using EFEP, a
UV-curable or other light or radiation curable polymer could be
used, thus allowing for curing of the polymer without application
of such high temperature.
[0033] In a preferred embodiment, the polymer comprises UV-curable
polymer. UV-curable is defined as a material that will react under
UV light to either cure or form a durable bond. The UV light can be
provided by a lamp having a suitable voltage, a suitable strength,
and a suitable wavelength. Curing with UV light may be carried out
for any suitable length of time, and the distance between the
sample being cured and the UV lamp can be any suitable distance.
All of the above parameters will be readily determinable by one
skilled in the art. In an aspect of the invention the UV curable
material can also be sensitive to visible light. However, preferred
conditions are present only under the UV spectrum (100-400 nm). The
preferred range is in the UVA spectrum (320-390 nm). Suitable
UV-curable polymers include, for example, acrylated epoxies,
acrylates, urethane acrylates, urethane methacrylates, silanes,
silicones, epoxides, epoxy methacrylates, triethylene glycol
diacetate, and vinyl ethers. Specific examples of these polymers
include acrylated aliphatic oligomers, acrylated aromatic
oligomers, acrylated epoxy monomers, acrylated epoxy oligomers,
aliphatic epoxy acrylates, aliphatic urethane acrylates, aliphatic
urethane methacrylates, alkyl methacrylate, amine-modified
oligoether acrylates, amine-modified polyether acrylates, aromatic
acid acrylate, aromatic epoxy acrylates, aromatic urethane
methacrylates, butylene glycol acrylate, stearyl acrylate,
cycloaliphatic epoxides, cylcohexyl methacrylate, ethylene glycol
dimethacrylate, epoxy methacrylates, epoxy soy bean acrylates,
glycidyl methacrylate, hexanediol dimethacrylate, isodecyl
acrylate, isooctyl acrylate, oligoether acrylates, polybutadiene
diacrylate, polyester acrylate monomers, polyester acrylate
oligomers, polyethylene glycol dimethacrylate, stearyl
methacrylate, triethylene glycol diacetate, and vinyl ethers.
Preferred UV-curable polymers include, for example, medical grade
UV-curable polymers such as DYMAX.RTM. 204 CTH UV-curable polymer
and DYMAX.RTM. 206 CTH UV-curable polymer (both commercially
available medical grade UV-curable polymers available from DYMAX
Corporation, Torrington, Conn.).
[0034] In addition to EFEP and UV-curable polymers, further
suitable polymer materials can include, for example,
thermoplastics, thermosets, pressure sensitive adhesives,
heat-activated adhesives, and chemically activated adhesives.
[0035] Preferred polymer materials include thermoplastics that melt
below the temperature that would cause the outer tube and/or
polymer film to melt. This allows the polymer tape wraps (when
used) to fuse together without melting the polymer tape, without
reflowing the outer polymer tube and, thus, without losing the
pattern embossed into the outer polymer tube. UV-curable adhesives
can be particularly attractive in this aspect of the invention.
Particularly attractive are medical grade UV-curable polymers, such
as the above-mentioned DYMAX.RTM. 204 CTH and DYMAX.RTM. 206
CTH.
[0036] The particular polymer used will, of course, depend upon the
particular embodiment and desired results. Such polymers can be
provided in liquid or solid form. In an aspect of the invention,
polymers include, for example, THV (tetrafluoroethylene,
hexafluoropropylene, and vinylide fluoride, available from Dyneon),
EFEP (Daikin America), PE (polyolefin), polyamides,
polyacryl-amides, polyesters, polyolefins (e.g., polyethylene),
polyurethanes, and the like.
[0037] Suitable polymer application means include any method known
in the art. With regard to porous polymer films, suitable
application means include, for example, coating techniques (e.g.,
dip coating), solvent imbibing, vacuum assisted coating, pressure
assisted coating, nip coating, and other suitable means which
result in the polymer filling at least some of the porosity of the
porous polymer film.
[0038] It may be desirable to utilize a solvent to aid in providing
polymer to the porosity of the polymer film. The ratio of solvent
material to polymer can vary and will be readily determinable by
the skilled artisan. A 50/50 by weight solvent to polymer solution
may be particularly acceptable. Preferable solvent materials will
be readily apparent to one skilled in the art and include, for
example, alcohols, ketones, etc. Methyl ethyl ketone (MEK) may be
one particularly attractive solvent. When a solvent material is
utilized, the solvent material can be easily removed or driven off
once the polymer is provided to at least some of the porosity of
the porous film as desired.
[0039] The invention also relates to a method for forming catheters
having at least one lumen located in the catheter wall and
extending for at least a portion of the length of the catheter. The
at least one lumen can be formed by utilizing the polymer shrink
tubing, and particularly fluoropolymer shrink tubing, according to
the present invention. The invention further relates to a method of
forming catheters having easily tailorable properties and/or
altered cross-sections.
[0040] For example, a cylindrical, flowable plastic material (such
as Pebax.RTM. polyether block amides), having a generally central,
longitudinally extending lumen, is provided. In an aspect of the
invention, a cylindrical mandrel having a diameter equal to about
the desired inner diameter of a tubular member such as a catheter
can first be provided. The outer surface of the mandrel can be
coated with a lubricious material, such a PTFE. The cylindrical,
flowable plastic material optionally could first be located over
the mandrel to provide structural support to the flowable plastic
material during further processing. Furthermore, a suitable,
cylindrical polymer shrink tube having an inner and an outer
surface, with the inner surface having at least one
three-dimensional pattern thereon, can be placed over the flowable
plastic tube. Thereafter, a suitable energy source, such as hot air
can be applied to the shrink tube to shrink the tube around the
outer surface of the flowable plastic tube, causing the at least
one three-dimensional pattern to be embossed into the flowable
plastic tube. The temperature (and duration of application of heat)
should be sufficient to shrink the tubing and cause the pattern to
be embossed into the flowable plastic tube, but not so high (and/or
so long in duration) as to cause the three-dimensional pattern to
lose its form.
[0041] This embodiment is demonstrated in FIG. 3, where
three-dimensional pattern 1 is a longitudinally extending rib on
the inner surface of shrink tube 10. As can be seen, longitudinally
extending rib 1 extends into flowable plastic tube 20 during and
after the heating step described above. When shrink tube 10 is
removed, a catheter body having a tailored cross-section is
obtained, in this case a non-circular cross-section due to the
longitudinally extending channel formed in the plastic tube. This
will, of course, alter certain properties of the catheter body,
such as bending characteristics, when compared to catheters without
the longitudinally extending channel. It should be understood that
other three-dimensional patterns could be embossed into the
flowable plastic tube to result in various tailored cross-sections
and result in various altered catheter properties.
[0042] FIG. 4 shows an alternative embodiment, which further
comprises a thin-walled (e.g., about 1.5 mil wall thickness)
tubular liner 30 of a suitable material (such as PTFE) as the inner
member of the tubular structure. Obviously, this embodiment can be
obtained by first placing the thin-walled liner over the mandrel
(if used) and then following the sequence described above. FIG. 5
shows, in cross section, a further alternative embodiment which
further includes metal coil (such as stainless steel or nitinol
coil) material 40 located between the inner, thin-walled liner 30
and the flowable plastic tube 20. Of course, the metal coil could
be at least partially embedded into the flowable plastic tube, as
discussed above. In an aspect of the invention the metal coil is a
helically wrapped stainless steel coil measuring about
0.002''.times.0.012'' that can extend any desired length of the
tube. As mentioned above, the metal coil material 40 could be
substituted with any desirable reinforcing material, which will be
readily apparent to those skilled in the art.
[0043] In an aspect of the invention polymer shrink tube is used to
cause the at least one three-dimensional pattern to be embossed
into the flowable plastic tube and to cause or assist the flowable
plastic to embed the optional reinforcing material. This is
preferably accomplished during a single heating (or other energy
application) step. For example, an extruded PTFE tube could be
placed over a mandrel, as discussed above. A suitable reinforcing
material, such as stainless steel or nitinol coil could be placed
over the PTFE tube. A flowable plastic tube could be placed over
the reinforcing material and then a polymer shrink tube having at
least one three-dimensional pattern on the inner surface thereof
could be placed over the flowable plastic tube. Suitable energy,
such as heat, could then be applied to the assembly to cause the
polymer shrink tube to shrink. As the tube shrinks, the flowable
plastic tube can at least partially embed, or substantially
completely embed, the metal reinforcement while, at the same time,
the at least one three-dimensional pattern is embossed into the
flowable plastic tube. The at least one three-dimensional pattern
could be a longitudinally extending rib, which results in a
longitudinally extending channel being embossed into the flowable
plastic tube. After allowing the assembly to cool, the polymer
shrink tube can be removed and the at least one pattern could be
covered with polymer film, as discussed above.
[0044] As shown in FIG. 5, shrink tube 10 has been removed, thus
resulting in longitudinally extending channel 3. Moreover, the
outer polymer tube 20 has been provided with polymer film cover 50,
thus defining a longitudinally extending lumen in the outer polymer
tube 20. In an aspect of the invention, polymer film 50 is provided
as a helical wrap of ePTFE at least partially imbibed with suitable
polymer, such as UV curable polymer or EFEP, as described
above.
[0045] It should be understood that any number of longitudinally
extending channels could be provided to the embodiment discussed
above, by providing a plurality of longitudinally extending ribs to
the shrink tubing 10. In an aspect of the invention, four
longitudinally extending channels, each about 90.degree. apart, are
provided. In a further aspect of the invention, each of the four
channels has dimensions essentially equal to one another. In a
further aspect of the invention, each channel has a width of about
0.015 inch and a depth of about 0.007 inch. Once covered with
suitable polymer film, four longitudinally extending lumens would
be obtained. These lumens could be used, for example, to deliver
inflation fluid to an expandable member on a distal end of a
catheter, to pass strings/wires/or fluids down the length of a
catheter, to deliver electrical, sensing, mechanical steering, or
device deployment devices, etc. Moreover, the lumen(s) could be
used to locate at least one material in the catheter wall that will
alter at least one property of the catheter. For example, a
stiffening wire could be located in a lumen for part of the length
of the catheter, or for the entire length of the catheter. The
stiffening wire could be located in the lumen before or after
providing the polymer film cover. Further, the lumen could be
filled, partially or completely, with any suitable material (e.g.,
polymer, metal, etc.) to alter the catheter's stiffness along at
least a portion of the length of the catheter. According to this
aspect of the invention it is possible to produce catheters having
varying properties (e.g., stiffness) along the length of the
catheter.
[0046] Turning to FIG. 6, there is shown in longitudinal cross
section, one potential catheter embodiment according to the present
invention. As shown, the catheter 100 includes an inflatable member
5 located at the distal end 7 of the catheter. Thin-walled liner 30
(e.g., fluoropolymer such as PTFE) extends for the length of the
catheter and defines inner, centrally located lumen 6. Positioned
over the inner liner 30 is polymer tube 20, which also can extend
for the length of the catheter. Not shown is optional reinforcing
material, such as metal coil or braid (described above), which can
also extend for the length of the catheter and be positioned over
thin-walled liner 30 and optionally embedded into polymer tube 20.
Polymer film wrap 50 can also extend for the length of the catheter
and cover longitudinally extending channel 3, thus defining
longitudinally extending lumen in polymer tube 20. As shown,
longitudinally extending channel 3 can function as an inflation
lumen and is in fluid communication with inflation port 4 and the
interior of inflatable member 5.
[0047] As should be understood, catheter 100 can be appropriately
sized for any number of desirable applications, such as those
discussed in the commonly owned patents and patent applications,
discussed above. Moreover, there is no requirement that an
inflatable member is located at the distal end of the catheter, or
provided at all. Furthermore, additional lumens could be provided
in polymer tube 20. Such lumens could be used to allow for delivery
of delivery catheters, balloon-on-a-wire devices, thrombectomy
removal devices, steering wires, diagnostic catheters, angiographic
catheters, etc., as well as to be used to locate at least one
material in the catheter wall such as a stiffening wire, as
discussed above.
[0048] While particular embodiments of the present invention have
been illustrated and described herein, the present invention should
not be limited to such illustrations and descriptions. It should be
apparent that changes and modifications may be incorporated and
embodied as part of the present invention within the scope of the
following claims.
* * * * *