U.S. patent application number 15/658037 was filed with the patent office on 2018-01-18 for high flexibility, kink resistant catheter shaft.
The applicant listed for this patent is NeuVT Limited. Invention is credited to Stephen W. Anderson, Andrew H. Cragg, John Logan.
Application Number | 20180015248 15/658037 |
Document ID | / |
Family ID | 59745314 |
Filed Date | 2018-01-18 |
United States Patent
Application |
20180015248 |
Kind Code |
A1 |
Logan; John ; et
al. |
January 18, 2018 |
HIGH FLEXIBILITY, KINK RESISTANT CATHETER SHAFT
Abstract
An enhanced flexibility catheter shaft having an elongate
flexible body with a proximal end, a distal end, and at least one
lumen extending therethrough. A distal, flexible section on the
body has a ribbed or corrugated tubular membrane having at least a
first reinforcement structure, such as a first helical support, on
a radially exterior or interior surface of the membrane and
optionally a second reinforcement structure, such as a second
helical support, on the other of the radially interior or exterior
surface of the membrane
Inventors: |
Logan; John; (Plymouth,
MN) ; Anderson; Stephen W.; (Minneapolis, MN)
; Cragg; Andrew H.; (Edina, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NeuVT Limited |
Dublin |
|
IE |
|
|
Family ID: |
59745314 |
Appl. No.: |
15/658037 |
Filed: |
July 24, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15647763 |
Jul 12, 2017 |
|
|
|
15658037 |
|
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|
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62361984 |
Jul 13, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/95 20130101; A61M
25/0045 20130101; A61M 25/0012 20130101; A61M 25/0068 20130101;
A61M 25/001 20130101; A61M 25/005 20130101; A61M 25/0108 20130101;
A61M 25/10 20130101; A61M 25/0052 20130101; A61M 25/0053 20130101;
A61M 25/0054 20130101; A61M 25/09 20130101; A61M 2025/0059
20130101 |
International
Class: |
A61M 25/00 20060101
A61M025/00; A61M 25/01 20060101 A61M025/01; A61M 25/09 20060101
A61M025/09 |
Claims
1.-30. (canceled)
31. An enhanced flexibility catheter shaft, comprising: an elongate
flexible body, having a proximal end, a distal end, and at least
one lumen extending therethrough; a distal, flexible section on the
body, comprising a tubular membrane having a first helical support
on a radially exterior surface of the membrane and a second helical
support on a radially interior surface of the membrane.
32. (canceled)
33. An enhanced flexibility catheter shaft as in claim 31, wherein
an inside diameter of the first helical support is less than an
inside diameter of the second helical support.
34. (canceled)
35. (canceled)
36. (canceled)
37. An enhanced flexibility catheter shaft as in claim 31, wherein
at least one of the first and second helical supports is floating
with respect to the tubular membrane.
38. An enhanced flexibility catheter shaft as in claim 37, wherein
both of the first and second helical supports are floating with
respect to the tubular membrane.
39. (canceled)
40. (canceled)
41. (canceled)
42. (canceled)
43. An enhanced flexibility catheter shaft as in claim 31, wherein
the membrane comprises PTFE.
44. (canceled)
45. (canceled)
46. (canceled)
47. (canceled)
48. (canceled)
49. An enhanced flexibility catheter shaft as in claim 31, wherein
the tubular membrane comprises a helical pleat.
50. (canceled)
51. (canceled)
52. An enhanced flexibility catheter shaft as in claim 31, wherein
the distal, flexible section has an outer an outer diameter of at
least about 6 French and a % bending load of no more than about
50.
53. (canceled)
54. (canceled)
55. An enhanced flexibility catheter shaft as in claim 31, wherein
the distal, flexible section has an outer diameter of at least
about 8 French and a % bending load of no more than about 60.
56. (canceled)
57. (canceled)
58. (canceled)
59. (canceled)
60. An enhanced flexibility catheter shaft, comprising: an elongate
flexible tubular body, having a proximal end, a distal end, and at
least one lumen extending therethrough; a distal, flexible section
on the body, comprising a tubular membrane having an outside
surface with a plurality of radially outwardly extending annular
ribs spaced apart by radially inwardly extending recesses, and an
inside surface with a plurality of radially inwardly facing annular
concavities corresponding to the radially outwardly extending
annular ribs, and an annular support carried within at least one of
the radially inwardly extending recesses and the radially inwardly
facing annular concavities.
61. An enhanced flexibility catheter shaft as in claim 60, wherein
the plurality of radially outwardly extending annular ribs comprise
revolutions of a continuous helical rib.
62. (canceled)
63. An enhanced flexibility catheter shaft as in claim 61,
comprising a first helical support extending within the radially
inwardly extending recesses.
64. An enhanced flexibility catheter shaft as in claim 63,
comprising a second helical support extending within the radially
inwardly facing annular concavities.
65. (canceled)
66. (canceled)
67. An enhanced flexibility catheter shaft as in claim 64, wherein
the membrane extends in between the first helical support and the
second helical support without being bonded to either of the first
helical support and the second helical support along a length of
the distal section.
68. An enhanced flexibility catheter shaft, comprising: an elongate
flexible tubular body, having a proximal end, a distal end, and at
least one lumen extending therethrough; a distal, flexible section
on the body, comprising a corrugated tubular membrane; a first
spiral support carried on the outside surface of the tubular
membrane; and a second spiral support carried on the inside surface
of the tubular membrane; wherein at least one of the first and
second spiral supports is floating with respect to the adjacent
membrane.
69. An enhanced flexibility catheter shaft as in claim 68, wherein
both of the first and second spiral supports are floating with
respect to the adjacent membrane.
70. (canceled)
Description
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/647,763, filed Jul. 12, 2017, which claims
the benefit of U.S. Provisional Application No. 62/361,984, filed
Jul. 13, 2016, which is hereby incorporated by reference in its
entirety herein.
[0002] Any and all applications for which a foreign or domestic
priority claim is identified in the Application Data Sheet as filed
with the present application are hereby incorporated by reference
under 37 CFR 1.57.
BACKGROUND
Field
[0003] The present disclosure relates to a flexible catheter for
endovascular procedures.
Description of the Related Art
[0004] Nearly all endovascular procedures require the use of
flexible catheters, for example, to deliver contrast injection, to
deliver implantable devices, perform vascular procedures, or to
aspirate. Due to the tortuous nature of the vasculature, it is
important for catheters to be flexible enough to travel through
vessels without excessive force. However, there is generally a
trade-off between the features of catheter diameter, trackability,
flexibility, and kink resistance. An increase in catheter diameter
tends to increase its stiffness, which lowers its trackability and
may dangerously increase vascular sheer forces. An increase in
flexibility tends to increase the tendency of the catheter to kink
as it is pushed through the vasculature, which limits the catheter
to vessels with gentle curves.
SUMMARY
[0005] Traditional catheter shafts have a braided/coiled wire
reinforcing element encapsulated in a plastic matrix to form a
tube. The catheter shaft may or may not have a coaxial liner layer.
With these conventional designs, the inherent flexibility of the
base wire frame is significantly reduced when encapsulated in the
non-distensible plastic matrix. To facilitate trackability, some
catheter designs vary the inner/outer diameter of the catheter
and/or the durometer of the plastic material. However, when the
resulting reinforced tube is flexed, a great deal of energy goes
into stretching the plastic matrix on the outside curve and
compressing the plastic matrix on the inside curve of the tube.
This is less pronounced on small diameter catheters, but more
significant as diameter gets larger. Further, varying the durometer
creates potential kinking points at the durometer transition
points. This conventional construction also provides limited force
transmission or pushability due to buckling or ovalization of the
distal shaft. It would be desirable to have a catheter that did not
show deteriorating trackability and kink resistance as the diameter
increased.
[0006] The present disclosure is directed toward catheter shaft
designs that are more flexible than conventional shafts and that
demonstrate a unique set of properties such as relative
independence of catheter diameter and stiffness, catheter diameter
and trackability, and catheter stiffness and kink resistance. The
catheter shafts described below permit the passage of larger
diameter catheters through tortuous vascular anatomy and to more
distal vascular anatomy, while providing improved resistance to
compression or ovalization during bending. This increase in
flexibility is coupled with an improved kink resistance for a given
catheter diameter.
[0007] Some aspects of the disclosure are directed toward an
elongate flexible body with a proximal end, a distal end, and at
least one lumen extending therethrough. A distal, flexible section
on the body has a tubular membrane having at least a first
reinforcement structure, such as a first helical support, on a
radially interior or exterior surface of the membrane. A second
reinforcement structure, such as a second helical support, on the
other of the radially interior or exterior surface of the membrane
may also be provided.
[0008] Controlled hinging (e.g., pleating or corrugating) of the
tubular membrane during bending reduces the tendency of the tubular
membrane to buckle or kink at a focal bending point. In some
embodiments, the tubular membrane is supported by opposing inner
and outer coils as described above, which can promote the
controlled hinging. In some embodiments, the tubular membrane is
supported by only an outer coil or an inner coil that is affixed to
the tubular membrane by an ultra-thin layer of a suitable plastic,
such as Kynar, that does not restrict the pleating of the tubular
membrane.
[0009] Some aspects of the disclosure are directed toward a highly
flexible, kink resistant catheter with floating tubular support.
The catheter can include an elongate tubular body having a proximal
end, a distal end and a central lumen. The tubular body can include
an inner tubular layer surrounding the lumen. A helical support can
be carried concentrically over the inner layer. Adjacent loops
spaced axially apart. The pitch of the adjacent loops can be varied
to adjust for flexibility and pushability. An outer tubular layer
can be carried concentrically over the helical support. The inner
layer and the outer layer are bonded together in the space between
adjacent loops of the tubular support to form a helical channel and
the helical support is floating unbonded within the helical
channel, e.g., the tubular support is not molecularly or physically
attached to the inner layer or the outer layer. The cross sectional
area of the helical channel can be varied from an area just larger
than the wire cross sectional area to an area up to 10.times.
larger than the wire cross sectional area in order to facilitate
free movement of the wire helix.
[0010] Any feature, structure, or step disclosed herein can be
replaced with or combined with any other feature, structure, or
step disclosed herein, or omitted. Further, for purposes of
summarizing the disclosure, certain aspects, advantages, and
features of the inventions have been described herein. It is to be
understood that not necessarily any or all such advantages are
achieved in accordance with any particular embodiment of the
inventions disclosed herein. No individual aspects of this
disclosure are essential or indispensable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Various embodiments are depicted in the accompanying
drawings for illustrative purposes, and should in no way be
interpreted as limiting the scope of the embodiments. Furthermore,
various features of different disclosed embodiments can be combined
to form additional embodiments, which are part of this
disclosure.
[0012] FIG. 1 is a schematic representation of a conventional
catheter.
[0013] FIG. 2 shows a distal portion of a catheter having a single
reinforcement structure.
[0014] FIG. 3 is a schematic representation of the catheter shown
in FIG. 2.
[0015] FIG. 4 shows a distal portion of another catheter having a
single reinforcement structure.
[0016] FIG. 5 shows a distal portion of a catheter having two
reinforcement structures.
[0017] FIG. 6 is a schematic representation of the catheter shown
in FIG. 5.
[0018] FIG. 7A is a schematic representation of a cross-section of
the distal portion of the catheter shown in FIG. 5 in a bent
configuration.
[0019] FIG. 7B schematically illustrates an inner bend of the
distal portion shown in FIG. 7A.
[0020] FIG. 7C schematically illustrates an outer bend of the
distal portion shown in FIG. 7A.
[0021] FIG. 8 is a schematic representation of another catheter
having two reinforcement structures.
[0022] FIG. 9 is a schematic illustrate of yet another embodiment
of a catheter having a single reinforcement structure.
[0023] FIG. 10 is a graph of stiffness v. outer diameter for
various catheter devices.
[0024] FIGS. 11A-11D illustrate yet another catheter having a
single reinforcement structure.
[0025] FIG. 12 is a flow chart demonstrating one method of
manufacturing the catheter shown in FIG. 11A.
[0026] FIG. 13 is a schematic representation of yet another
catheter having a single reinforcement structure.
DETAILED DESCRIPTION
[0027] To improve flexibility, conventional catheter designs often
vary a durometer of the polymer tubing along the catheter shaft.
FIG. 1 schematically illustrates a conventional catheter 10 having
a plurality of sections of polymer tubing 12, 14, 16 forming an
outer surface of the catheter 10. Each section 12, 14, 16 has a
different durometer. Often, the durometer of the polymer tubing
transitions every few centimeters. The transition points between
the different sections can increase the likelihood of kinking.
Further, the softer durometer sections can increase resistance when
the outer surface of the catheter contacts a vessel wall.
[0028] An inner surface of the catheter 10 can be formed by a liner
18, which can limit flexibility by providing a relatively stiff
backbone. A stiffer catheter tends to create increased resistance
when the inner surface of the catheter contacts the guide wire
and/or the outer surface of the catheter contacts the vessel. The
catheter shaft designs described below provide improved
flexibility, trackability, and kink resistance, even for catheters
having larger diameters.
Fibrous Encapsulated Reinforcement Structure
[0029] FIG. 2 depicts a distal portion 102 of a catheter 100 having
a reinforcement structure (sometimes referred to herein as an
annular support) encapsulated in a fibrous coating. FIG. 3
schematically illustrates the catheter 100 including the distal
portion 102 of the catheter shown in FIG. 2 and a proximal portion
104. The proximal portion 104 can include one or more sections
(e.g., one, two, three, or more) of polymer tubing 106, 108. When
the proximal portion 104 has multiple sections 106, 108, each
section 106, 108 can have a different diameter that generally
increases in the proximal direction toward the hub 110. The
distal-most section 106 of the proximal portion 104 can be
generally stiffer than any portion of the distal portion 102. The
proximal portion 104 may or may not have a liner 112 positioned
radially inward of the one or more sections 106, 108.
[0030] The catheter 100 can have at least one lumen. For catheters
having a single lumen, an inner diameter at a proximal end of the
distal portion 102 can be substantially the same as an inner
diameter at a distal end of the proximal portion 104. In some
configurations, an inner diameter of the catheter 100 can be
substantially the same along the entire length of the catheter.
[0031] At least the distal portion 102 can include a reinforcement
structure 114. In FIGS. 2 and 3, the reinforcement structure 114 is
a coil, but in other implementations, can be a mesh, braided
structure, laser cut structure, parallel spaced apart rings,
helical z patterns, diamond patterns, or other structure capable of
providing column strength and radial strength. The reinforcement
structure 114 can include a medical grade metal material, such as
nitinol, stainless steel, or otherwise, or a polymeric material,
such as PEEK, Kevlar, carbon fiber filaments, or otherwise.
Although the illustrated embodiment includes a single reinforcement
structure 114 at a distal portion 102 of the catheter 100,
additional reinforcement structures 114 may be added, for example,
radially inward and/or radially outward of a coating 116, and/or
the reinforcement structure 114 can form at least a part of the
proximal portion 104 of the catheter 100 or extend along the entire
length of the catheter 100.
[0032] At least the distal portion of the reinforcement structure
114 can be coated with a coating such as fibrous coating 116. The
coating 116 can be applied to an inner and/or outer surface of the
reinforcement structure 114 using an electrospinning process. The
fibrous coating 116 can be formed from a thermoplastic
fluoropolymer. Exemplary materials for the fibrous coating 116 can
include, but are not limited to, PTFE, PET, silicone, latex,
TecoThane, nylon, PET, Carbothane (Bionate), SIBS, TecoFlex,
Pellethane, Kynar, and PGLA. The fibrous nature of the coating 116
allows the catheter to stretch, which imparts flexibility.
Preferably the coating remains impermeable at least to
erethrocytes, or is completely fluid impermeable in the vascular
environment. Although the illustrated embodiment includes a coating
116 at a distal portion 102 of the catheter 100, the coating 116
can extend at least partially into the proximal portion 104 of the
catheter 100 or along the entire length of the catheter 100.
[0033] The reinforcement structure 114 can also be coated or
embedded in a non-electrospun membrane such as a tubular hydrogel.
For example, the reinforcement structure can be spray coated, dip
coated or otherwise provided with a thin, highly flexible layer of
a methacrylate polymer such as poly(HEMA), preferably in such a way
that the coating is strongly adherent, e.g., there is no detachment
of the coating from the underlying coil surface. Other hydrophilic
and non-hydrophilic polymeric coating materials may alternatively
be used, such as those obtained by polymerization of monomers
selected from hydroxyethoxyethyl methacrylate (HEEMA),
hydroxydiethoxyethyl methacrylate (HDEEMA), methoxyethyl
methacrylate (MEMA), methoxyethoxyethyl methacrylate (MEEDA),
metoxydiethoxyethyl methacrylate (MDEEMA), ethylene glycol
dimethacrylate (EGDMA) and mixtures thereof. These polymeric
coatings can be crosslinked or non-crosslinked depending upon the
desired performance. These polymeric materials can be copolymers,
terpolymers or even more complex macromolecular systems, or
physical blends. Adherence of the methacrylate polymer biomaterial
to the metallic surface of the supporting coil may be enhanced by
the application of a binder polymer layer. One such binder is
poly(ethersulfone). Additional details may be found in US patent
Publication 2002/0065551 entitled Method for Immobilizing
poly(HEMA) on Stents, to Koole, et al., which is hereby
incorporated by reference in its entirety herein.
[0034] Electrospinning refers generally to processes involving the
expulsion of flowable material from one or more orifices, and the
material forming fibers are subsequently deposited on a collector.
Examples of flowable materials include dispersions, solutions,
suspensions, liquids, molten or semi-molten material, and other
fluid or semi-fluid materials. In some instances, the rotational
spinning processes are completed in the absence of an electric
field. For example, electrospinning can include loading a polymer
solution or dispersion, including any of the materials described
below, into a cup or spinneret configured with orifices on the
outside circumference of the spinneret. The spinneret is then
rotated, causing (through a combination of centrifugal and
hydrostatic forces, for example) the flowable material to be
expelled from the orifices. The material may then form a "jet" or
"stream" extending from the orifice, with drag forces tending to
cause the stream of material to elongate into a small diameter
fiber. The fibers may then be deposited on a collection apparatus.
Further information regarding electrospinning can be found in U.S.
Publication No. 2013/0190856, filed Mar. 13, 2013, and U.S.
Publication No. 2013/0184810, filed Jan. 15, 2013, which is
incorporated by reference in its entirety herein.
[0035] The catheter 100 can be formed by taking a mandrel having a
diameter of the desired inner diameter of the catheter 100. Several
layers of the coating 116 can be spun over the mandrel, and then
the reinforcement structure 114 can be positioned over the spun
material. Thereafter, another several layers of coating 116 can be
spun over the reinforcement structure 114 such that the
reinforcement structure 114 is encapsulated within the coating 116.
The outer layers of coating 116 can fill in the interstitial spaces
in the reinforcement structure 114, such as between the bends in a
coil.
[0036] The fibrous encapsulated reinforcement structure allows for
a catheter construction in which the region of greatest flexibility
is provided over a greater length than traditional catheters.
Unlike traditional catheters in which a durometer of the plastic
matrix transitions a few centimeters from the distal end, the
coating 116 described herein can have a generally uniform stiffness
(e.g., by providing a generally constant thickness, and/or density)
along a length of the distal portion 102 or along an entire length
of the coating 116. The length of generally uniform stiffness can
be at least about 1.0 cm, at least about 2.0 cm, at least about 4.0
cm, at least about 5.0 cm, at least about 10.0 cm, at least about
15.0 cm, at least about 20.0 cm, at least about 50.0 cm, or an
entire length of the catheter.
[0037] As mentioned above, in conventional catheter designs, the
coating on the outside curve stretches while the coating on the
inside curve compresses, which can result in kinking. The fibrous
encapsulated reinforcement structure mitigates kinking seen in
larger diameter catheters having an outer diameter of at least
about 5.0 F, such as between about 6.0 F and about 12.0 F, between
about 8.0 F and 10.0 F, or otherwise, because the coating generally
demonstrates better stretch and compression than conventional
plastic catheter jacketing materials. Larger diameter catheters can
be useful to ease the passage of other devices through a lumen of
the catheter or to provide greater aspiration forces for a given
aspiration pressure. It should be noted that this construction
could be applied to any catheter diameter, including catheter
diameters less than about 5.0 F or greater than about 12 F.
[0038] FIG. 4 depicts a catheter 200 with a reinforcement structure
extending along a length of the catheter. The distal portion 202
can be coated with a fibrous coating as described above. The
coating can transition from the fibrous coating at the distal
portion 202 to a polymer tubing at the proximal portion 204 at
transition point e.
[0039] The stiffness of the coating can be varied along the length
of the distal portion 202 by changing the coating density or
varying a thickness of the coating or the coating material. The
thickness of the coating can be varied between 0.1 mm and 1 mm to
change the stiffness and permeability of the covering. For example,
the distal portion 202 can have multiple sections (e.g., two,
three, four, or more) of varying stiffness that are separated by
transition points a, b, c, d. A stiffness of the coating generally
increases in the proximal direction toward the proximal portion 204
of the catheter 200. A length of the coating can have a generally
uniform stiffness, thickness, and/or density. The length of
generally uniform stiffness, thickness, and/or density can be at
least about 1.0 cm, at least about 2.0 cm, at least about 4.0 cm,
at least about 5.0 cm, at least about 10.0 cm, at least about 15.0
cm, at least about 20.0 cm, at least about 50.0 cm, an entire
length of the catheter, or otherwise. This length of uniform
coating may be measured from a distal end of the catheter 200.
Dual Reinforcement Structure
[0040] FIG. 5 shows a distal portion 302 of a catheter 300 having
two reinforcement structures (sometimes referred to herein as
annular supports) separated by a tubular membrane. FIG. 6
schematically illustrates a catheter 300 including the distal
portion 302 of the catheter shown in FIG. 5 and a proximal portion
304. The distal portion 302 and the proximal portion 304 can have a
same inner diameter. The proximal portion 304 can include one or
more sections 306, 308 (e.g., one, two, three, or more) of polymer
tubing each having a different durometer. When the proximal portion
304 has multiple sections 306, 308, the durometer of each section
306, 308 can increase in the proximal direction toward the hub 310.
The distal-most section 306 of the proximal portion 304 is
generally stiffer than any portion of the distal portion 302. The
proximal portion 304 may or may not have a liner 312 positioned
radially inward of the one or more sections 306, 308. Providing a
catheter 300 without a liner 312 in the distal portion 302 of the
catheter 300 increases the flexibility in the distal portion 302
compared to conventional catheters.
[0041] At least the distal portion 302 can include an outer
reinforcement structure 318 and an inner reinforcement structure
314. For example, in FIGS. 5 and 6, the reinforcement structures
318, 314 are helical-shaped support structures (e.g., round wire
coils or flat wire coils). The pitch of one or both of the
helical-shaped support structures can be between about 0.01 inches
to about 0.03 inches, between about 0.015 inches and about 0.25
inches, or otherwise. The reinforcement structures 318, 314 can
include a medical grade metal material, such as nitinol, stainless
steel, or otherwise, or a polymeric material, such as PEEK, Kevlar,
carbon fiber filaments, or otherwise. Although the preferred
embodiment of the reinforcement structures is a helical wire, other
similar embodiments could include a mesh, braided structure, laser
cut structure, parallel spaced apart rings, helical z patterns,
laser cut diamond patterns, or other structure capable of providing
column strength and radial strength.
[0042] As shown in FIG. 6, the tubular membrane 316 can have a
helical convoluted or corrugated structure having a plurality of
radially outwardly projecting helical ribs 320 on the outer surface
of the tubular membrane 316 and a plurality of radially inwardly
projecting helical ribs 322 on the inner surface of the tubular
membrane 316 (or viewed another way helical grooves on inner and
outer surfaces of the tubular membrane 316).
[0043] In some embodiments, the tubular membrane 316 can be
constructed from an inelastic plastic material (e.g., PTFE), but
even when the tubular membrane 316 is inelastic, the corrugations
provide flexibility in an otherwise stiff tubular member 316. When
the distal portion 302 of the catheter 300 bends, flexibility is
primarily provided by the unfolding of the corrugations on the
outer bend and folding of the corrugations on the inner bend, not
stretching. Other exemplary materials for the tubular membrane 316
can include, but are not limited to, expanded PTFE (ePTFE),
electrospun PTFE, PET, silicone, latex, TecoThane, nylon, PET,
Carbothane (Bionate), SIBS, TecoFlex, Pellethane, Kynar, and
PGLA.
[0044] The formation of an organized corrugated wall structure
during bending provides flexibility while reducing the likelihood
of kinking. As the catheter shaft is bent, the amplitude of the
corrugations on the outer bend 316a decreases and the amplitude of
the corrugations on the inner bend 316b increases (see FIG. 7A).
Further, as the catheter shaft is bent, the wavelength
.lamda..sub.1 of the corrugations on the inner bend 316b decreases
(see FIG. 7B) and the wavelength .lamda..sub.2 of the corrugations
on the outer bend 316a increases (see FIG. 7C). In a bent
configuration, the average wavelength of the corrugations on the
inner bend 316b can be less than the average wavelength of the
corrugations on the outer bend 316a, and the average amplitude of
the corrugations on the inner bend 316b can be greater than the
average amplitude of the corrugations on the outer bend 316a.
[0045] Referring to FIG. 7A, a reference line 330 may be drawn
perpendicular to a longitudinal axis of the catheter shaft, such
that it crosses the tubular wall at a first point 334 and a second
point 336. A second reference line 332, spaced apart from the first
reference line 330 also resides perpendicular to the longitudinal
axis of the catheter, and crosses the wall at a first point 338 and
a second point 340. When the catheter is oriented linearly, first
reference line 330 is parallel to and spaced apart from the second
reference line 332.
[0046] The distance between reference points 334 and 338 is equal
to the distance 336-340, when the catheter is in a linear
configuration. As shown in FIG. 7A, the distance 334-338 (inside
length) is less than the distance 336-340 (outside length), when
the catheter is in a curved configuration.
[0047] Due to the significant axial compression and expansion of
the sidewall of catheters built in accordance with the present
disclosure, the catheter shaft can be wrapped into a relatively
tight radius bend without kinking. For example, a catheter shaft
having an OD of at least about 0.05 inches or 0.1 inches or greater
may be bent such that the outside length is at least about 200% and
in some constructions at least about 300% or 400% of 500% or more
the inside length. Axial compression of the wall along the inside
length is accomplished by decreasing the wavelength between
adjacent ribs along the inside length as shown in FIG. 7B, and/or
increasing the wavelength between adjacent ribs along the outside
length as shown in FIG. 7C.
[0048] Catheters having an outside diameter of at least about 0.05
inches, in some implementations at least about 0.08 inches, or 0.1
inches or 0.2 inches or more can be bent around a radius of
curvature for the inside length of less than about 0.075 inches,
and in some embodiments less than about 0.05 inches, 0.04 inches,
or 0.025 inches or less, without kinking.
[0049] In some implementations of the catheter shaft, a catheter
having an OD of at least about 0.05'' (e.g., 0.066''), or at least
about 0.1'' (e.g., 0.111'') can have an OD to kink radius ratio of
at least about 2.0, or 2.5 or 3.0 or 3.5 or more. Kink radius is
the radius at the point when kinking first occurs, so bending the
catheter shaft around the kink radius or a smaller radius will
cause a kink in the catheter shaft.
[0050] The corrugations permit the catheter shaft to assume a
relatively tight radius of curvature without kinking or stressing
the plastic tubular membrane in either stretch or compression. The
combination of corrugations and helical reinforcement structures
314, 318 produces a catheter shaft with ideal properties that are
normally in competition, e.g., flexibility with high resistance to
compression or kinking, because the reinforcement structures 314,
318 provide support to and facilitate alignment of the of the
corrugations in the tubular membrane 316. When the distal portion
302 of the catheter bends, an arcuate portion 317 of the bend
hinges in a generally uniform manner so that the catheter does not
buckle or kink in any single position. For example, for a catheter
300 having an outer diameter of less than or equal to about 5.0 F,
the distal portion 302 will not kink when bent to form an arcuate
portion 317 having a radius (measured from the inner curvature) of
no more than about 0.01 inches, no more than about 0.015 inches, no
more than about 0.02 inches, no more than about 0.25 inches, or no
more than about 0.3 inches. As another example, for a catheter 300
having an outer diameter of less than or equal to about 8.0 F, the
distal portion 302 will not kink when bent to form an arcuate
portion 317 having a radius (measured from the inner curvature) of
no more than about 0.4 inches or no more than about 0.5 inches.
[0051] The pitch of the inner groove of the tubular membrane 316
can be approximately the same as the pitch of the inner
reinforcement structure 314, and the pitch of the outer groove of
the tubular membrane 316 can be approximately the same as the pitch
of the outer reinforcement structure 318. The depth of the inner
groove can be at least about 1.times. and often between about
1.5.times. and 2.0.times. a radial dimension such as a diameter of
the wire forming the inner reinforcement structure 314, and the
depth of the outer groove can be between about 1.5.times. and
2.0.times. a radial dimension such as a diameter of the wire
forming the outer reinforcement structure 318. If the reinforcement
structures were rings instead of helices, the tubular membrane
would have a recurring series of ring-like corrugations rather than
a helical pattern.
[0052] The outer reinforcement structure 318 can be positioned in
the outer helical groove such that the helical rib 320 extends
through the interstitial spaces of the adjacent outer reinforcement
structure 318. The inner reinforcement structure 314 can be
positioned in the inner helical groove such that the helical rib
322 extends through the interstitial spaces of the second
reinforcement structure 318. With this design, both the inner and
outer surfaces of the distal portion 302 of the catheter 300 are
textured, which can decrease resistance when the outer surface of
the catheter contacts a vessel wall.
[0053] The inner diameters of the outer and inner reinforcement
structures 318, 314 can differ from each other, e.g., by at least
about 0.001 inches (or at least about 0.005 inches) and/or by less
than a diameter of the wire forming the reinforcement structures
318, 314. The diameter of the wires can be larger than wires in
conventional catheters because the reinforcement structures 318,
314 do not need to be fully encased in a plastic matrix. For
example, the diameter of the wires can be between about 0.003
inches and about 0.007 inches, such as between about 0.004 inches
and about 0.005 inches in a catheter intended for neurovascular
access. The larger diameter wire provides greater hoop strength,
crush resistance, and kink resistance than traditional construction
techniques.
[0054] In some implementations, the outer reinforcement structure
318 can have a smaller inner diameter than at least an outer
diameter or an inner diameter of the inner reinforcement structure
314. The inner diameter of the inner reinforcement structure 314
can be at least about 1% greater than, at least about 2% greater,
or at least about 5% greater than an inner diameter of the outer
reinforcement structure 318. For example, in a 9.0 F catheter, the
outer reinforcement structure 318 can have an inner diameter of
0.100 inches and the inner diameter of the inner reinforcement
structure 314 can have an inner diameter of 0.105 inches. With this
configuration, the inner reinforcement structure 314 presses upward
or outward on the tubular membrane 316 and the outer reinforcement
structure 318 presses inward on the tubular membrane 316 to retain
the assembled configuration of the catheter 300. This configuration
also creates deeper grooves in the tubular membrane 316 such that
there is a greater length of the tubular membrane 316 (e.g.,
greater arc length or greater length when flattened) between
adjacent bends in either reinforcement structure 318, 314. The
deeper corrugations provide more flexibility.
[0055] At least one of the reinforcement structures 318, 314 is not
encapsulated in the tubular membrane 316. Rather, at least one or
both of the reinforcement structures 318, 314 floats with respect
to the tubular membrane 316. Unlike conventional catheters, the
reinforcement structures 318, 314 are floating (e.g., not fully
encapsulated and/or joined to the tubular membrane 316), so the
flexibility of reinforcement structures 318, 314 is preserved
without negatively affecting the wall thickness and overall size of
the catheter. This increased flexibility enables the use of a
larger overall diameter catheter to perform the same tasks that are
typically performed using a smaller diameter catheter. It should be
understood that corrugation of the tubular membrane would increase
the catheter shaft flexibility whether or not the reinforcement
structures are floating with respect to the tubular membrane or
encapsulated by the tubular membrane, but when the reinforcement
structures are floating with respect to the tubular membrane, the
catheter may have greater flexibility and trackability.
[0056] When the portion of the catheter 300 having the
above-described construction is flexed, each groove or pleat on an
outer curve of the bent catheter 300 flexes outward a few degrees
(e.g., one degree, two degrees, three degrees, or more) to
accommodate the change in geometry. Since the reinforcement
structures 318, 314 are not encapsulated in a plastic matrix, there
is very little energy needed to bend the catheter 300 compared to
conventional catheters.
[0057] This type of catheter construction allows for a catheter in
which the region of greatest flexibility is provided over a greater
length than traditional catheters. Unlike traditional catheters in
which a durometer of the plastic matrix transitions a few
centimeters from the distal end, the distal portion 302 can have a
generally uniform stiffness profile along a length of the distal
portion 302, or over at least a length of at least about 1.0 cm, at
least about 2.0 cm, at least about 4.0 cm, at least about 5.0 cm,
at least about 10.0 cm, at least about 15.0 cm, at least about 20.0
cm, at least about 50.0 cm, or an entire length of the catheter.
The length of uniform stiffness can be measured from a distal end
of the catheter. Compared to conventional catheters, there are
fewer transition points between sections of varying stiffness,
which reduces the number of transition points that are prone to
kinking.
[0058] The distal portion 302 of the catheter can be mated to the
proximal portion 306 of the catheter in a butt joint.
Alternatively, as described in further detail below, one or more of
the tubular membrane 316, outer reinforcement structure 318, and
the inner reinforcement structure 318 can extend into a proximal
portion 304 of the catheter 300 to join the distal portion 302 and
the proximal portion 304 and reduce the likelihood of kinking at
the connection.
[0059] The proximal end of the inner reinforcement structure 314
can be encapsulated in the polymer tubing of the proximal portion
304, e.g., in the distal-most or softest durometer section 306. The
proximal end of the outer reinforcement structure 318 can be
encapsulated in the same section of tubing 306 or extend proximally
toward the hub 310 within the walls of the polymer tubing 306, 308
or radially outward of the polymer tubing 306, 308. The distal ends
of the inner and outer reinforcement structures 314, 318 can be
encapsulated in a polymer jacket that may be separate from the
tubular membrane 316. Polymer jacketing material may be bonded to
one or more parts of the distal portion 302 to improve kink
resistance.
[0060] FIG. 6 schematically illustrates the tubular membrane 316
only extending along a length of the distal portion 302 and/or a
length of the reinforcement structures 318, 314. However, in other
configurations, the tubular membrane 316 and/or the coils may
extend proximally of the distal portion 302 by at least about 1 cm
or 5 cm or 10 cm or more in a proximal direction from the proximal
end of the distal portion 302. For example, the tubular membrane
316 may form at least part of or the entirety of the liner 312 of
the proximal portion 304. The tubular membrane 316 and/or the coils
can have a thickness of less than or equal to about 0.01 inches or
less than or equal to about 0.001 inches. The tubular membrane 316
can be constructed from a polymer such as PTFE, ePTFE, electrospun
PTFE, silicone, latex, TecoThane, nylon, PET, Carbothane (Bionate),
SIBS, TecoFlex, Pellethane, PGLA, or Kynar.
[0061] The properties of the dual reinforcement structure design
are generally insensitive to catheter diameter, thus the design can
be applied to larger diameter catheters having an outer diameter of
at least about 5.0 F and/or less than or equal to about 12.0 F,
between about 8.0 F and 10.0 F. Larger diameter catheters can be
useful to ease the passage of other devices through a lumen of the
catheter or to provide greater aspiration forces for a given
aspiration pressure. It should be noted that this construction
could be applied to any catheter diameter, including catheter
diameters less than 5.0 F or greater than 12.0 F.
[0062] Although the schematic illustration in FIG. 6 shows the
distal tip 324 being cut perpendicular to the longitudinal axis of
the catheter, in other configurations, the distal tip 324 can be
cut at an oblique angle to the longitudinal axis of the catheter
(as shown in FIG. 5) to facilitate trackability at bifurcations.
For aspiration catheters, the beveled tip can increase a surface
area at the distal end 324 for engaging the clot, thus increasing
total suction force on a surface such as an embolus. The beveled
tip may also prevent the clot from clogging the catheter by
creating a larger end hole through which an embolus can pass. In
some configurations, the distal tip may be a soft, flexible tip to
create a seal against the emboli surface. In some configurations,
the distal tip 324 may have a feature (e.g., offset channel or
lumen) to force the guidewire to one side of the distal opening to
facilitate trackability.
[0063] Although not shown, the construction at the distal portion
302 of the catheter may extend along an entire working length of
the catheter 300. A durometer of the reinforcement structures 318,
314 and/or the tubular membrane 316 can generally increase in the
proximal direction to provide the desired stiffness profile.
[0064] One method of forming the catheter 300 is to first form the
individual components. To form the corrugations in the tubular
membrane, the tubular membrane 316 can be positioned on a mandrel
having a helical groove and a tensioned wire can be positioned on
top of the tubular membrane 316 to force portions of the membrane
into the groove in the mandrel. The tubular membrane 316 can be
heat set to fix the corrugations in the tubular membrane 316. To
form the reinforcement structures 314, 318, wires can be wrapped
around mandrels having the desired inner diameter of the respective
reinforcement structure 314, 318 and heat set. The final assembly
is formed by mating the two reinforcement structures 314, 318 with
the respective grooves in the tubular membrane 316. With the inner
reinforcement structure 314 positioned on a mandrel, the tubular
membrane 316 can be wound over the inner reinforcement structure
314. Next, the outer reinforcement structure 318 can be wound
around the groove in the outer surface of the tubular membrane.
[0065] FIG. 8 illustrates another catheter 400 having dual
reinforcement structures. The distal portion 402 resembles or is
identical to the distal portion 302 discussed above in many
respects. Accordingly, numerals used to identify features of the
catheter 300 are incremented by a factor of one hundred (100) to
identify like features of the catheter 400. Any component or step
disclosed in this embodiment can be used in other embodiments
described herein.
[0066] As mentioned above, the inner and/or outer reinforcement
structure 314, 318 can extend proximally of the distal portion 302
to provide support to the proximal portion 304 (e.g., to prevent
kinking). For example, as shown in FIG. 7, the outer reinforcement
structure 418 can provide the proximal support and extend along a
length of catheter 400. The outer reinforcement structure 418 can
be encapsulated in the one or more sections of polymer tubing 406,
408. The inner reinforcement structure 414 can terminate within a
distal section 406 of the proximal portion 404. For example, a
proximal end of the inner reinforcement structure 414 can extend
through a thickness of the tubular membrane 416 and into a wall of
the distal-most section of polymer tubing 406. In this
configuration, the proximal ends of both reinforcement structures
418, 414 can be fully encapsulated in the polymer tubing 406, 408
forming the proximal portion 404.
[0067] In other configurations, the inner reinforcement structure
414 can provide the proximal support and extend along at least a
partial or entire length of the proximal portion 404. The inner
reinforcement structure 414 can be encapsulated in the one or more
sections of polymer tubing 406, 408. The outer reinforcement
structure 418 can terminate in a wall of the polymer tubing at the
distal-most section 406 of the proximal portion 406 or be
positioned radially outward of the proximal portion 406 and extend
along at least a partial or entire length of the proximal portion
406.
Single Reinforcement Structure Affixed to Tubular Membrane
[0068] FIG. 9 illustrates another embodiment of a catheter with a
single reinforcement structure 518 (sometimes referred to herein as
an annular support). At least a distal portion 502 of the catheter
500 can include a reinforcement structure 518 and a tubular
membrane 516. As shown in FIG. 9, the reinforcement structure 518
is on an outer surface of the tubular membrane 516, but in other
configurations, the reinforcement structure 518 could be positioned
on an inner surface of the tubular membrane 516.
[0069] The reinforcement structure 518 can be a helical-shaped
support structures (e.g., a round wire coil or flat wire coil). The
pitch of the helical-shaped support structures can be between about
0.01 inches to about 0.03 inches, between about 0.015 inches and
about 0.25 inches, or otherwise. The reinforcement structure 518
can include a medical grade metal material, such as nitinol,
stainless steel, or otherwise, or a polymeric material, such as
PEEK, Kevlar, or carbon fiber filaments, or otherwise. Although the
preferred embodiment of the reinforcement structures is a helical
wire, other similar embodiments could include a mesh, braided
structure, laser cut structure, diamond patterns, parallel spaced
apart rings, helical z patterns, or other structure capable of
providing column strength and radial strength rings.
[0070] The tubular membrane 516 can have a helical convoluted,
pleated, or corrugated structure having a helical rib 520 on the
outer surface of the tubular membrane 516. The tubular member 516
can be inelastic and constructed from a polymer material (e.g.,
PTFE), but even when the tubular membrane 516 is inelastic, the
corrugations provide flexibility. The corrugations permit the
catheter 500 to assume a relatively tight radius of curvature
without kinking or stressing the plastic tubular membrane in either
stretch or compression. The properties of the corrugated structure
are generally the same as the corrugated structure described above
with respect to FIGS. 7A-7C. Other exemplary materials for the
tubular membrane 516 can include, but are not limited to, ePTFE,
electrospun PTFE, PET, silicone, latex, TecoThane, nylon, PET,
Carbothane (Bionate), SIBS, TecoFlex, Pellethane, Kynar, and
PGLA.
[0071] The pitch of the outer groove of the tubular membrane 516
can be approximately the same as the pitch of the reinforcement
structure 518. The depth of the outer groove can be between about
1.5.times. and 2.0.times. a diameter of the wire forming the outer
reinforcement structure 318. If the reinforcement structure 518 has
rings instead of helices, the tubular membrane 516 would have a
recurring series of ring-like corrugations rather than a helical
pattern.
[0072] The reinforcement structure 518 can be positioned in the
outer helical groove such that the helical rib 520 extends through
the interstitial spaces of the reinforcement structure 518. The
corrugations on the inner and outer surfaces of the distal portion
502 of the catheter 500 provide texturing, which can decrease
resistance when the outer surface of the catheter contacts a vessel
wall.
[0073] The reinforcement structure 518 can be affixed to the
tubular membrane 516 by a thin polymer coating 530 (e.g., a Kynar
or urethane coating). The coating may be applied using a spray
coating technique. The thickness for the coating 530 can be less
than or equal to about 0.01 inches, less than or equal to about
0.001 inches, or less than or equal to about 0.0005 inches. For
example, the coating can be sprayed over the assembled catheter
500, such that the coating 530 fills the spaces between the
reinforcement structure 518 and the surface of the tubular membrane
516. Although, in other configurations, the reinforcement structure
518 could be floating with respect to the tubular membrane 516 as
described with respect to catheter 300.
[0074] Similar to the catheter 300, when the distal portion 502 of
the catheter 500 bends, an arcuate portion of the bend hinges in a
generally uniform manner so that the catheter does not buckle or
kink in any single position. The reinforcement structure 518
promotes and supports the uniform hinging of the tubular membrane
516. Although the reinforcement structure 518 is affixed to the
tubular membrane 516, the polymer coating 530 is sufficiently thin
to not appreciably increase an overall thickness of the
catheter.
[0075] As shown in FIG. 9, the reinforcement structure 518 can
extend proximally of the distal portion 502 to provide support to
the proximal portion 504 (e.g., to prevent kinking). For example,
the reinforcement structure can provide the proximal support and
extend along a length of catheter 500. The reinforcement structure
518 can be encapsulated in the one or more sections of polymer
tubing 506, 508. The tubular membrane 516 can extend proximally and
provide an inner lining of the proximal portion 504. In other
constructions, the reinforcement structure 518 may terminate in the
distal portion 502 or in a distal portion of the proximal portion
504.
Stiffness v. Outer Diameter
[0076] As described above, the catheter construction of the dual
reinforcement structure design can provide greater flexibility than
conventional catheters, particularly for larger diameter catheters.
FIG. 10 is a graph showing catheter outer diameter v. stiffness for
the distal portion of the dual reinforcement structure catheter
described herein (e.g., catheter 300 or catheter 400) compared to
the most flexible portion of other commercially available catheter
designs. The stiffness of the catheter can be measured as a
percentage of the bending load using an ASTM D 747 test (standard
test method for apparent bending modulus of plastics by means of a
cantilever beam).
[0077] As shown in FIG. 10, the stiffness of the distal portion of
the dual reinforcement structure catheter is generally at least
less than half of the stiffness of the most flexible portion of
commercially available catheters for catheters having an outer
diameter up to at least about 10.0 F. The stiffness of a distal
portion of a catheter having the dual reinforcement structure
design (e.g., catheter 300 or catheter 400) can have a stiffness of
less than or equal to about 40% of a bending load for a catheter
having an outer diameter up to and including about 10.0 F, less
than or equal to about 30% of a bending load for a catheter having
an outer diameter up to and including about 8.0 F, or less than or
equal to about 20% of a bending load for a catheter having an outer
diameter up to and including about 6.0 F. In some implementations,
the stiffness of a catheter having an outer diameter of at least
about 4.0 F can have a percentage bending load of no more than
about 30, or no more than about 20. In some implementations, the
stiffness of a catheter having an outer diameter of at least about
6.0 F can have a % bending load of no more than about 50, or no
more than about 40, or no more than about 30, or no more than about
20. In some implementations, the stiffness of a catheter having an
outer diameter of at least about 8.0 F can have a percentage
bending load of no more than about 60, or no more than about 40, or
no more than about 30. In some implementations, the stiffness of a
catheter having an outer diameter of at least about 10.0 F can have
a percentage bending load of no more than about 80, or no more than
about 60, or no more than about 40. The outer diameter referred to
above can be measured along any portion of the catheter shaft, for
example, anywhere along the distal portion of the catheter
shaft.
Single Floating Reinforcement Structure
[0078] FIGS. 11A-11D illustrate another embodiment of a highly
flexible, kink resistant catheter 1100 having an elongate tubular
body. The catheter 1100 can include a distal portion 1104, a
proximal portion 1106, and a central lumen 1116. The proximal
portion 1106 and/or the transition 1105 between the distal portion
1104 and the proximal portion 1106 can include any of the
corresponding features of the above-described catheters.
[0079] The distal portion 1104 is more flexible than the proximal
portion 1106. The distal portion 1104 can have a generally uniform
stiffness profile over at least a length of at least about 1.0 cm,
at least about 2.0 cm, at least about 4.0 cm, at least about 5.0
cm, at least about 10.0 cm, at least about 15.0 cm, at least about
20.0 cm, at least about 50.0 cm of the catheter, or an entire
length of the elongate tubular body. The length of uniform
stiffness can be measured from a distal end 1102 of the catheter
1100.
[0080] As shown in FIG. 11B, at least the distal portion 1104 can
include a helical support 1114 positioned concentrically between an
inner tubular layer 1110 and an outer tubular layer 1112. The inner
tubular layer 1110 can define at least a portion of the central
lumen 1116 of the catheter 1100. The helical support 1114 can be
carried concentrically over the inner layer 1110. Adjacent loops of
the helical support 1114 can be axially spaced apart at least when
the catheter 1100 is at rest. The outer tubular layer 1112 can be
carried concentrically over the helical support 1114. The outer
tubular layer 1112 can extend at least a length of the distal
portion 1104 or the entire length of the elongate tubular body.
[0081] The inner tubular layer 1110 and the outer tubular layer
1112 are bonded together in the space 1120 between adjacent loops
of the helical support 1114 to form a helical channel 1118, as
shown in FIG. 11B. The helical support 1114 is floating unbonded
within the helical channel 1118, e.g., the helical support 1114 is
not molecularly or physically attached to the inner tubular layer
1110 or the outer tubular layer 1112. The diameter of the best fit
circle corresponding to the size of the helical channel 1118
exceeds the diameter of the helical support 1114 by at least about
0.001 inches, at least about 0.0015 inches, or at least about 0.002
inches. In one implementation, no additional component, material,
or fluid is provided in the space between the helical support 1114
and a wall of the helical channel 1118. Because the helical support
1114 is unbonded with respect to inner and outer tubular layers
1110, 1112, the helical support 1114 is able to move freely, which
facilitates flexibility and trackability. If the catheter 1100 was
cut transversely through the distal portion 1104 of the catheter
1100 to produce a catheter body segment of about 2 cm in length,
the helical support 1114 could be removed by grasping a cut end of
the helical support 1114 and pulling the helical support 1114 out
of the helical channel 1118 non destructively, by hand.
[0082] The helical support 1114 can extend along at least a partial
length (e.g., the length of the distal portion) or a full length of
the catheter 1100 (e.g., from a distal tip 1102 to a proximal hub
1108). The helical support 1114 can be formed from wire (e.g.,
round wire or flat wire). The wire can include a medical grade
metal material, such as nitinol or stainless steel, or a polymeric
material, such as PEEK, Kevlar, carbon fiber filaments, or
otherwise. The helical support 1114 can have a constant inner
and/or outer diameter. The helical support 1114 can have a
cross-section in the radial direction of no more than about 0.006
inches, or no more than about 0.005 inches, no more than about
0.004 inches, or no more than 0.003 inches. The pitch of the
helical support can be between about 0.01 inches to about 0.03
inches, between about 0.01 inches to about 0.018 inches, between
about 0.015 inches and about 0.25 inches, or otherwise. In some
configurations, the pitch can vary over a length of the helical
support 1114. For example, the helical support 1114 could have a
reduced pitch at the proximal loops compared to the distal loops.
The pitch may gradually increase from the proximal end toward the
distal end of the helical support 1114. Although the reinforcement
structure in this embodiment is a helical wire, other similar
embodiments could include a mesh, helical z patterns, braided
structure, laser cut structure, diamond patterns, parallel spaced
apart rings, or other structure capable of providing column
strength and radial strength rings.
[0083] The inner tubular layer 1110 and/or the outer tubular layer
1112 can include PTFE, ePTFE, electrospun PTFE, silicone, latex,
TecoThane, nylon, PET, Carbothane (Bionate), SIBS, TecoFlex,
Pellethane, PGLA, or Kynar. The inner tubular layer 1110 and/or
outer tubular layer 1112 can include a thickness of no more than
about 0.004 inches, or no more than about 0.002 inches. The inner
and outer tubular layers 1110, 1112 in at least the distal portion
1104 can be formed from a single section of material or two
different sections of similar or different material. The inner
diameter and/or outer diameter of the distal portion 1102 of the
catheter 1100 can be constant (e.g., a smooth surface) or vary
(e.g., a corrugated surface). As shown in FIG. 11B, the distal
portion 1104 can include a corrugated outer surface and a smooth
inner surface. The corrugated outer surface can decrease resistance
when the outer surface of the catheter contacts a vessel wall.
[0084] As explained further below, the inner tubular layer 1110 can
be formed from a single segment or two different segments of
material (e.g., a proximal section and a distal section). In
instances where the inner tubular layer 1110 is formed from two
different segments of material, the two segments can be joined by a
skived joint. The two segments can be joined at the transition 1105
between the proximal portion 1106 and the distal portion 1102.
[0085] As shown in FIG. 11C, the distal tip 1102 of the catheter
1100 can be cut perpendicular to a longitudinal axis of the
catheter 1100. However, in other configurations, the distal tip
1102 can be cut at an oblique angle relative to the longitudinal
axis of the catheter 1100. The distal tip 1102 may have a feature
(e.g., offset channel or lumen) to force the guidewire to one side
of the distal opening to facilitate trackability. In some
configurations, the distal tip 1102 can include a soft, flexible
tip to create a seal against the emboli surface.
[0086] The distal tip 1102 can include a radiopaque marker 1122. As
shown in FIG. 11C, the radiopaque marker 1122 can be positioned
radially between the inner tubular layer 1110 and the outer tubular
layer 1112. The radiopaque marker 1122 can include tungsten,
tantalum, platinum alloys, or otherwise. Because of the radiopaque
marker 1122, a thickness of the distal tip 1102 may be greater than
a region adjacent to the distal tip 1102.
[0087] The design of catheter 1100 can be applied to larger
diameter catheters having an outer diameter of at least about 5 F
and/or less than or equal to about 12 F, between about 8 F and 10
F. It should be noted that this construction could be applied to
any catheter diameter, including catheter diameters less than 5 F
or greater than 12 F. A wall thickness of the distal portion of any
sized catheter (e.g., 5 F, 6 F, 7 F, 8 F, 9 F, or otherwise) is
less than or equal to about 0.006 inches, or less than or equal to
about 0.005 inches.
[0088] Catheters 1100 having an outside diameter of at least about
0.05 inches, in some implementations at least about 0.08 inches, or
0.1 inches or 0.2 inches or more can be bent around a radius of
curvature for the inside length of less than about 0.1 inches, and
in some embodiments less than about 0.08 inches, without
kinking.
[0089] The distal portion 1104 can have an outer diameter to kink
radius ratio of at least about 1.2, or at least about 1.475. Kink
radius is the radius at the point when kinking first occurs, so
bending the catheter shaft around the kink radius or a smaller
radius will cause a kink in the catheter shaft. For example, for a
catheter 1100 having an outer diameter of less than or equal to
about 9 F, the distal portion 1104 will not kink when bent to form
an arcuate portion having a radius (measured from the inner
curvature) of no more than about 0.1 inches or no more than about
0.08 inches. As another example, for a catheter 1100 having an
outer diameter of less than or equal to about 8.0 F, the distal
portion 1104 will not kink when bent to form an arcuate portion
having a radius (measured from the inner curvature) of no more than
about 0.1 inches or no more than about 0.08 inches.
[0090] Although catheter 1100 is described as having a single
helical support 1114, other configurations may include additional
helical supports axially aligned with the helical support 1114 in a
longitudinal dimension.
[0091] One method of manufacturing the catheter 1100 is described
below and outlined in FIG. 12. Although certain materials are
described below, other materials can be used as described above.
Any step disclosed below can be replaced with or combined with any
other step disclosed herein, reordered, or omitted.
[0092] In step 1202, the helical support 1114 can by formed by
winding a wire onto a mandrel to and heat setting the wire to form
a coil.
[0093] Separately, in step 1204, a layer of PTFE 1124 can be placed
over the catheter mandrel to form at least a portion (e.g., a
proximal portion) of the inner tubular layer 1110 of the catheter
1100. The layer of PTFE 1124 can be heat shrunk so the inner
tubular layer 1110 remains stationary when the helical support 1114
is transferred to the catheter mandrel. A skived section 1126 is
formed at the distal end of the layer of PTFE 1124 (e.g., at least
about 1.0 inches long). A layer of ePTFE 1128 is placed over the
mandrel so that the layer of ePTFE 1128 extends distally from the
layer of PTFE 1124. The layer of ePTFE 1128 will form at least a
portion of the inner tubular layer 1110 (e.g., distal portion)
and/or the outer tubular layer 1112 of the catheter 1100. The layer
of ePTFE 1128 can overlap the skived end 1126 of the PTFE layer
1124 by less than or equal to about 2.0 mm or less than or equal to
about 1.0 mm. This skived area facilitates a continuous transition
between the two layers of material. The layers of PTFE or ePTFE
referred to herein may be tubular segments of material or sheets of
material wrapped around the mandrel. In other configurations, the
inner tubular layer 1110 may be formed from a single layer, or the
inner and outer layers of the distal portion 1104 may be formed
from two different segments of material.
[0094] In step 1206, the helical support 1114 is transferred to the
catheter mandrel. A distal end of the helical support 1114 can be
glued to the layer of ePTFE 1126 to hold the helical support 1114
in place during the remaining steps of this process. In instances
where the catheter mandrel has an outer diameter that is greater
than an inner diameter of the helical support, the helical support
1114 is at least partially stressed.
[0095] In step 1208, a radiopaque marker 1122 can be placed in the
area of the distal end of the helical support 1114 (step 1208). The
radiopaque marker 1122 may overlap the distal end of the helical
support 1114. The radiopaque marker 1122 can be shrunk down and
melted into that section of the catheter 1100 to form part of the
distal tip 1102. The layer of ePTFE 1128 is folded around or
inverted over the radiopaque marker 1122 and extended proximally
over the helical support 1114 to form the outer tubular layer 1112.
Providing a continuous layer of material from the inside diameter,
around the distal tip to the outside diameter reduces the risk that
the inner and outer layers will separate and expose the helical
support 1114 and/or radiopaque marker 1122. In this configuration,
the inner and outer layers 1110, 1112 of at least the distal
portion 1104 are constructed from the same segment of material.
Another wire is coiled over at least the distal portion 1104 of the
outer tubular layer 1112 and in the spaces 1120 between adjacent
loops of the helical support 1114. This wire is used to create
enough pressure to sinter the inner tubular layer 1110 and the
outer tubular layer 1112 in the spaces 1120 between adjacent loops
of the helical support 1114. Through this sintering process, a
helical channel 1118 is formed between the inner tubular layer 1110
and the outer tubular layer 1112. The helical support 1114 remains
unbonded to the helical channel 1118 as discussed above. After the
sintering process, the wire is removed. In instances where the
inner and outer layers of the distal portion 1104 are formed by
different segments of material, the outer layer can be placed over
the helical support 1114 and sintered in the spaces 1120 between
adjacent loops of the helical support 1114 to form the helical
channel 1118.
[0096] The proximal portion 1106 of the catheter 110 is etched
(step 1210), and then one or more jackets of material are placed
over the proximal portion 1106 (step 1212). The polymer jacket can
include a material (e.g., polyether block amide) different from the
inner and/or outer tubular layers 1110, 1112. The polymer jacket(s)
can have a different durometer than the outer tubular layer 1110 to
form a stiffer profile. To the extent there are multiple jacket
segments, the jacket segments can have different diameters and be
arranged from harder durometer to softer durometer in the proximal
to distal direction. The one or more jackets are fused together and
over the helical support 1114 using standard bonding and reflow
methods (step 1212). In step 1216, the proximal hub 1108 is joined
to the proximal portion 1106. Optionally, at least the proximal
portion 1106 of the catheter 1100 is coated with a hydrophilic
coating (1218). The distal portion 1104 of the catheter can remain
uncoated.
Corrugated Inner Liner Surface Structure
[0097] FIG. 13 shows another embodiment of a catheter 1300 where
the catheter construction is comprised of a braided/coiled wire
reinforcing element 1318 encapsulated in a polymer (e.g., plastic)
matrix 1330 in at least a distal portion 1302 of the catheter 1300.
The inner liner layer 1316 is not substantially cylindrical in at
least a distal portion 1302 of the catheter 1300. The inner layer
surface 1316 is constructed in a helical/corrugated shape to allow
for a more flexible construct. The flexibility of this structure is
achieved by having a section comprised of a coil 1318 encapsulated
in the plastic matrix 1330 directly distal/proximal to a thin
section where there is only the plastic matrix 1330 with inner
liner 1318 without the coil component in spaces between adjacent
loops of the coil 1318. This construction allows for enhanced
flexibility by allowing a greater deflection at the sections
without the coil component compared to the coil-construction
region. This pattern of coil-construction and non-coil-construction
repeats along a helical pattern along the distal portion 1302 of
the device. The proximal portion 1304 can have a similar
construction to the proximal portion 504 of catheter 500.
[0098] This embodiment can be best fabricated by constructing the
"Dual Reinforcement Structure" (e.g., catheters 300, 400) described
above and thermally bonding a plastic matrix component 1330 to the
external surface of the construction. Once the plastic matrix 1330
is present, the internal metallic coil component can be removed to
have the resultant helical/corrugated shape of the inner layer
1316.
Terminology
[0099] The term "catheter" as used herein, is a broad term to be
given its ordinary and customary meaning to a person skilled in the
art and includes, without limitation, micro catheters, access
sheaths, guide catheters, aspiration catheters, balloon catheters,
stent delivery catheters, electrophysiology probes, general device
tubing, etc.
[0100] Conditional language, such as "can," "could," "might," or
"may," unless specifically stated otherwise, or otherwise
understood within the context as used, is generally intended to
convey that certain embodiments include, while other embodiments do
not include, certain features, elements, and/or steps. Thus, such
conditional language is not generally intended to imply that
features, elements, and/or steps are in any way required for one or
more embodiments.
[0101] The terms "comprising," "including," "having," and the like
are synonymous and are used inclusively, in an open-ended fashion,
and do not exclude additional elements, features, acts, operations,
and so forth. Also, the term "or" is used in its inclusive sense
(and not in its exclusive sense) so that when used, for example, to
connect a list of elements, the term "or" means one, some, or all
of the elements in the list.
[0102] The terms "approximately," "about," and "substantially" as
used herein represent an amount close to the stated amount that
still performs a desired function or achieves a desired result. For
example, the terms "approximately", "about", and "substantially"
may refer to an amount that is within less than 10% of, within less
than 5% of, within less than 1% of, within less than 0.1% of, and
within less than 0.01% of the stated amount.
[0103] The term "generally" as used herein represents a value,
amount, or characteristic that predominantly includes or tends
toward a particular value, amount, or characteristic. As an
example, in certain embodiments, the term "generally uniform"
refers to a value, amount, or characteristic that departs from
exactly uniform by less than 20%, less than 15%, less than 10%,
less than 5%, less than 1%, less than 0.1%, and less than
0.01%.
[0104] The ranges disclosed herein also encompass any and all
overlap, sub-ranges, and combinations thereof. Language such as "up
to," "at least," "greater than," "less than," "between" and the
like includes the number recited. Numbers preceded by a term such
as "about" or "approximately" include the recited numbers. For
example, "about 5.0 cm" includes "5.0 cm."
[0105] Some embodiments have been described in connection with
schematic drawings. However, it should be understood that the
schematic drawings are not drawn to scale. Distances are merely
illustrative and do not necessarily bear an exact relationship to
actual dimensions and layout of the devices illustrated.
[0106] For purposes of this disclosure, certain aspects,
advantages, and novel features are described herein. It is to be
understood that not necessarily all such advantages may be achieved
in accordance with any particular embodiment. Thus, for example,
those skilled in the art will recognize that the disclosure may be
embodied or carried out in a manner that achieves one advantage or
a group of advantages as taught herein without necessarily
achieving other advantages as may be taught or suggested
herein.
[0107] Moreover, while illustrative embodiments have been described
herein, the scope of any and all embodiments having equivalent
elements, modifications, omissions, combinations (e.g., of aspects
across various embodiments), adaptations and/or alterations as
would be appreciated by those in the art based on the present
disclosure. The limitations in the claims are to be interpreted
broadly based on the language employed in the claims and not
limited to the examples described in the present specification or
during the prosecution of the application, which examples are to be
construed as non-exclusive. Further, the actions of the disclosed
processes and methods may be modified in any manner, including by
reordering actions and/or inserting additional actions and/or
deleting actions. It is intended, therefore, that the specification
and examples be considered as illustrative only, with a true scope
and spirit being indicated by the claims and their full scope of
equivalents.
Example Embodiments
[0108] The following example embodiments identify some possible
permutations of combinations of features disclosed herein, although
other permutations of combinations of features are also
possible.
[0109] 1. A highly flexible, kink resistant catheter with floating
tubular support, comprising: [0110] an elongate tubular body,
having a proximal end, a distal end and a central lumen, the
tubular body comprising: [0111] an inner tubular layer surrounding
the lumen; [0112] a helical support, carried concentrically over
the inner layer and having adjacent loops spaced axially apart; and
[0113] an outer tubular layer, carried concentrically over the
helical support; [0114] wherein the inner layer and the outer layer
are bonded together in the space between adjacent loops of the
tubular support to form a helical channel and the helical support
is floating unbonded within the helical channel.
[0115] 2. A highly flexible catheter as in Embodiment 1, wherein at
least one of the inner and outer tubular layers comprises ePTFE or
electrospun PTFE.
[0116] 3. A highly flexible catheter as in Embodiment 2, wherein
the ePTFE has a wall thickness of no more than about 0.004''.
[0117] 4. A highly flexible catheter as in Embodiment 3, wherein
the ePTFE has a wall thickness of no more than about 0.002''.
[0118] 5. A highly flexible catheter as in any one of Embodiment 1
to 4, wherein the helical support comprises Nitinol wire.
[0119] 6. A highly flexible catheter as in Embodiment 5, wherein
the Nitinol wire has a cross section in the radial direction of no
more than about 0.006''.
[0120] 7. A highly flexible catheter as in Embodiment 6, wherein
the Nitinol wire has a circular cross section having a diameter of
about 0.004''.
[0121] 8. A highly flexible catheter as in any one of Embodiments 1
to 7, wherein the inner tubular layer comprises two distinct
sections, the two distinct sections comprising a proximal section
and a distal section.
[0122] 9. A highly flexible catheter as in Embodiment 8, wherein
the proximal section and the distal section of the inner tubular
layer comprise different materials.
[0123] 10. A highly flexible catheter as in Embodiment 8, wherein
the proximal section and the distal section are joined by a skived
joint.
[0124] 11. A highly flexible catheter as in any one of Embodiments
1 to 10, wherein the helical support extends from the distal end to
the proximal end of the tubular body.
[0125] 12. A highly flexible catheter as in any one of Embodiments
1 to 11, wherein a distal portion of the tubular body is more
flexible than a proximal portion of the tubular body.
[0126] 13. A highly flexible catheter as in Embodiment 12, wherein
the helical channel only extends through the distal portion of the
tubular body.
[0127] 14. A highly flexible catheter as in any one of Embodiments
1 to 13, wherein the inner tubular layer and the outer tubular
layer are formed from a single segment of material in at least a
distal portion of the elongate tubular body.
[0128] 15. A highly flexible catheter as in Embodiment 14, wherein
the single segment of material is folded over a distal end of the
helical support to form at least a portion of the inner tubular
layer and the outer tubular layer.
[0129] 16. A catheter, comprising: [0130] an elongate, flexible
inner layer positioned concentrically within an elongate, flexible
outer layer, the inner and outer layers joined by a helical bond to
form a helical channel defined between adjacent bonds; and [0131] a
helical support, floating in the helical channel.
[0132] 17. A catheter as in Embodiment 16, wherein at least one of
the inner and outer layers comprises ePTFE or electrospun PTFE.
[0133] 18. A catheter as in Embodiment 17, wherein the ePTFE has a
wall thickness of no more than about 0.004''.
[0134] 19. A catheter as in Embodiment 18, wherein the ePTFE has a
wall thickness of no more than about 0.002''.
[0135] 20. A catheter as in any one of Embodiments 16 to 19,
wherein the helical support comprises Nitinol wire.
[0136] 21. A catheter as in Embodiment 20, wherein the Nitinol wire
has a cross section in the radial direction of no more than about
0.006''.
[0137] 22. A catheter as in Embodiment 20, wherein the Nitinol wire
has a circular cross section having a diameter of about
0.004''.
[0138] 23. A catheter as in any one of Embodiments 16 to 22,
wherein the inner layer comprises two distinct sections, the two
distinct sections comprising a proximal section and a distal
section.
[0139] 24. A catheter as in Embodiment 23, wherein the proximal
section and the distal section of the inner tubular layer comprise
different materials.
[0140] 25. A catheter as in Embodiment 23, wherein the proximal
section and the distal section are joined by a skived joint.
[0141] 26. A catheter as in any one of Embodiments 16 to 25,
wherein the helical support extends from a distal end to a proximal
end of the catheter.
[0142] 27. A catheter as in any one of Embodiments 16 to 26,
wherein a distal portion of the catheter is more flexible than a
proximal portion of the catheter.
[0143] 28. A catheter as in Embodiment 27, wherein the helical
channel only extends through the distal portion of the
catheter.
[0144] 29. A catheter as in any one of Embodiments 16 to 28,
wherein the inner layer and the outer layer are formed from a
single segment of material in at least a distal portion of the
catheter.
[0145] 30. A catheter as in Embodiment 29, wherein the single
segment of material is folded over a distal end of the helical
support to form at least a portion of the inner tubular layer and
the outer tubular layer.
[0146] 31. An enhanced flexibility catheter shaft, comprising:
[0147] an elongate flexible body, having a proximal end, a distal
end, and at least one lumen extending therethrough; [0148] a
distal, flexible section on the body, comprising a tubular membrane
having a first helical support on a radially exterior surface of
the membrane and a second helical support on a radially interior
surface of the membrane.
[0149] 32. An enhanced flexibility catheter shaft as in Embodiment
31, wherein at least one of the first and second helical supports
comprises a nitinol wire.
[0150] 33. An enhanced flexibility catheter shaft as in Embodiments
31 or 32, wherein an inside diameter of the first helical support
is less than an inside diameter of the second helical support.
[0151] 34. An enhanced flexibility catheter shaft of any one of
Embodiments 31 to 33, wherein a pitch of the first helical support
is within the range of from about 0.010 inches to about 0.030
inches.
[0152] 35. An enhanced flexibility catheter shaft as in Embodiment
34, wherein a pitch of the first helical support is within the
range of from about 0.015 inches to about 0.025 inches.
[0153] 36. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 35, wherein at least the first helical support
comprises a wire having a diameter within the range of from about
0.003 inches to about 0.007 inches.
[0154] 37. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 36, wherein at least one of the first and second
helical supports is floating with respect to the tubular
membrane.
[0155] 38. An enhanced flexibility catheter shaft as in Embodiment
37, wherein both of the first and second helical supports are
floating with respect to the tubular membrane.
[0156] 39. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 38, wherein the distal, flexible section has an
axial length of at least about 1.0 cm.
[0157] 40. An enhanced flexibility catheter shaft as in Embodiment
39, wherein the distal, flexible section has an axial length of at
least about 15 cm.
[0158] 41. An enhanced flexibility catheter shaft as in Embodiment
33, wherein an inside diameter of the second helical support is at
least about 2% greater than the inside diameter of the first
helical support.
[0159] 42. An enhanced flexibility catheter shaft as in Embodiment
41, wherein an inside diameter of the second helical support is
about 0.105 inches and the inside diameter of the first helical
support is about 0.100 inches.
[0160] 43. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 42, wherein the membrane comprises PTFE.
[0161] 44. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 43, wherein the membrane comprises ePTFE.
[0162] 45. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 44, further comprising a proximal section, having
less flexibility than the distal section.
[0163] 46. An enhanced flexibility catheter shaft as in Embodiment
45, further comprising an intermediate section, having less
flexibility than the distal section and greater flexibility than
the proximal section.
[0164] 47. An enhanced flexibility catheter shaft as in Embodiment
46, wherein the tubular membrane extends proximally from the distal
section at least at least part way across the intermediate
section.
[0165] 48. An enhanced flexibility catheter shaft as in Embodiment
47, wherein the tubular membrane extends proximally from the distal
section at least as far as the proximal section.
[0166] 49. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 48, wherein the tubular membrane comprises a
helical pleat.
[0167] 50. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 4 French and a % bending load of
no more than about 30.
[0168] 51. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 4 French and a % bending load of
no more than about 20.
[0169] 52. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer an outer diameter of at least about 6 French and a % bending
load of no more than about 50.
[0170] 53. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 6 French and a % bending load of
no more than about 40.
[0171] 54. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 6 French and a % bending load of
no more than about 30.
[0172] 55. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 8 French and a % bending load of
no more than about 60.
[0173] 56. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 8 French and a % bending load of
no more than about 40.
[0174] 57. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 10 French and a % bending load of
no more than about 80.
[0175] 58. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 10 French and a % bending load of
no more than about 60.
[0176] 59. An enhanced flexibility catheter shaft as in any one of
Embodiments 31 to 49, wherein the distal, flexible section has an
outer diameter of at least about 10 French and a % bending load of
no more than about 40.
[0177] 60. An enhanced flexibility catheter shaft, comprising:
[0178] an elongate flexible tubular body, having a proximal end, a
distal end, and at least one lumen extending therethrough; [0179] a
distal, flexible section on the body, comprising a tubular membrane
having an outside surface with a plurality of radially outwardly
extending annular ribs spaced apart by radially inwardly extending
recesses, and an inside surface with a plurality of radially
inwardly facing annular concavities corresponding to the radially
outwardly extending annular ribs, and [0180] an annular support
carried within at least one of the radially inwardly extending
recesses and the radially inwardly facing annular concavities.
[0181] 61. An enhanced flexibility catheter shaft as in Embodiment
60, wherein the plurality of radially outwardly extending annular
ribs comprise revolutions of a continuous helical rib.
[0182] 62. An enhanced flexibility catheter shaft as in Embodiment
60, wherein the plurality of radially outwardly extending annular
ribs comprises discrete rings spaced apart axially along the distal
section.
[0183] 63. An enhanced flexibility catheter shaft as in any one of
Embodiments 60 to 62, comprising a first helical support extending
within the radially inwardly extending recesses.
[0184] 64. An enhanced flexibility catheter shaft as in Embodiment
63, comprising a second helical support extending within the
radially inwardly facing annular concavities.
[0185] 65. An enhanced flexibility catheter shaft as in any one of
Embodiments 60 to 64, wherein the annular support is unattached to
the adjacent tubular membrane.
[0186] 66. An enhanced flexibility catheter shaft as in Embodiment
64, wherein the membrane extends in between the first helical
support and the second helical support without being bonded to at
least one of the first helical support and the second helical
support along a length of the distal section.
[0187] 67. An enhanced flexibility catheter shaft as in Embodiment
64, wherein the membrane extends in between the first helical
support and the second helical support without being bonded to
either of the first helical support and the second helical support
along a length of the distal section.
[0188] 68. An enhanced flexibility catheter shaft, comprising:
[0189] an elongate flexible tubular body, having a proximal end, a
distal end, and at least one lumen extending therethrough; [0190] a
distal, flexible section on the body, comprising a corrugated
tubular membrane; [0191] a first spiral support carried on the
outside surface of the tubular membrane; and [0192] a second spiral
support carried on the inside surface of the tubular membrane;
[0193] wherein at least one of the first and second spiral supports
is floating with respect to the adjacent membrane.
[0194] 69. An enhanced flexibility catheter shaft as in Embodiment
68, wherein both of the first and second spiral supports are
floating with respect to the adjacent membrane.
[0195] 70. An enhanced flexibility catheter shaft, comprising:
[0196] an elongate flexible tubular body, having a proximal end, a
distal end, and at least one lumen extending therethrough; and
[0197] a distal, flexible section on the body, comprising a
corrugated tubular membrane; [0198] wherein the tubular body has an
outer diameter of at least about 6 French and a % bending load of
no more than about 40.
* * * * *