U.S. patent application number 17/504387 was filed with the patent office on 2022-02-17 for bend-limited catheters.
The applicant listed for this patent is PIPE Therapeutics LLC. Invention is credited to John-Paul ROMANO.
Application Number | 20220047850 17/504387 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-17 |
United States Patent
Application |
20220047850 |
Kind Code |
A1 |
ROMANO; John-Paul |
February 17, 2022 |
BEND-LIMITED CATHETERS
Abstract
Described herein are bend-limited catheters (e.g., apparatuses,
including devices and systems) and methods of using them. These
apparatuses may include an elongate tubular body that has one or
more cut-out kerfs forming a pattern of interlocking teeth that are
arranged in rings (and/or one or more spiral patterns) around the
perimeter of the elongate tubular body. The pattern of interlocking
teeth is configured to provide the catheter with a high degree of
flexibility in bending, while permitting the device to lock at a
locking diameter when the catheter bends to a minimum locking
angle, beyond which no further bending is permitted.
Inventors: |
ROMANO; John-Paul;
(Chalfont, PA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
PIPE Therapeutics LLC |
Gladwyne |
PA |
US |
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|
Appl. No.: |
17/504387 |
Filed: |
October 18, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16273135 |
Feb 11, 2019 |
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17504387 |
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62629069 |
Feb 11, 2018 |
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62651049 |
Mar 30, 2018 |
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International
Class: |
A61M 25/01 20060101
A61M025/01; A61M 25/09 20060101 A61M025/09 |
Claims
1. A bend-limited catheter device having a length extending in a
long axis, the device comprising: a tubular body having one or more
cut-out kerfs forming a pattern of interlocking and alternating
teeth extending around the tubular body, the pattern repeating from
a distal region to a proximal region of the tubular body, wherein
each tooth of the interlocking and alternating teeth comprises a
head region that is wider than a base region, arranged so that the
head regions alternate with base regions radially around the
tubular body, so that the tubular body bends in a direction out of
a long axis of the bend-limited catheter device up to a locking
radius, beyond which the tubular body does not allow further
bending in the direction; wherein each tooth of the interlocking
and alternating teeth forms a tooth angle between a line extending
through a width of the head region and a line extending from the
head region and the base region; further wherein a proximal portion
of the pattern of interlocking and alternating teeth comprises
teeth having an average tooth angle that is less than an average
tooth angle of a more distal portion of the pattern of interlocking
and alternating teeth.
2. The device of claim 1, wherein the more distal portion of the
pattern of interlocking and alternating teeth is configured to
expand from a compressed elongate length by between about 0.005
inches and 0.085 inches per every 0.1 inch of the length of the
pattern, further wherein the proximal portion is configured to
expand from a compressed elongate length by less than the more
distal portion of the pattern of interlocking and alternating
teeth.
3. The device of claim 1, wherein the more distal portion is
immediately adjacent to the proximal portion.
4. The device of claim 1, wherein the more distal portion of the
pattern of interlocking and alternating keystone-shaped teeth
extends more than 2 cm along the long axis, further wherein the
proximal portion of the pattern of interlocking and alternating
keystone-shaped teeth that extends more than 2 cm along the long
axis.
5. The device of claim 1, wherein the more distal portion of the
pattern of interlocking and alternating teeth has a pitch to
tubular body diameter ratio that is between 0.09 and 0.30 and a
pitch to tubular body diameter ratio of the proximal portion of the
pattern of interlocking and alternating keystone-shaped teeth that
is between 0.30 and 0.90.
6. The device of claim 1, wherein the more distal portion of the
pattern of interlocking and alternating teeth comprises 20 or more
teeth per revolution around a diameter of the tubular body, and
wherein the proximal portion of the pattern of interlocking and
alternating teeth comprises between 6-20 teeth per revolution
around the diameter of the tubular body.
7. The device of claim 1, wherein the teeth each form a keystone
shape.
8. The device of claim 1, wherein the one or more cut-out kerfs
have a diameter of between 0.0005 and 0.002 inches.
9. The device of claim 1, wherein the tubular body comprises one or
more of: steel, tungsten, and Nitinol.
10. The device of claim 1, further comprising a sealing material
extending across the cut-out kerfs.
11. The device of claim 10, wherein the sealing material is
laminated to the tubular body.
12. The device of claim 10, wherein the sealing material has a
Shore A durometer hardness of greater than 75.
13. The device of claim 10, wherein the sealing material is
laminated to an inner surface of the tubular body.
14. The device of claim 10, wherein the sealing material is
laminated to an outer surface of the tubular body.
15. The device of claim 1, further comprising an inflatable balloon
on the bend-limited catheter device.
16. The device of claim 1, wherein the locking radius of the more
distal portion of the pattern of interlocking and alternating teeth
is more than 15% smaller than the locking radius of the proximal
portion of the pattern of interlocking and alternating teeth.
17. The device of claim 16, wherein the locking radius of the
proximal portion of the pattern of interlocking and alternating
teeth is between 15 cm and 35 cm.
18. A bend-limited catheter device having a length extending in a
long axis, the device comprising: a tubular body having one or more
cut-out kerfs forming a pattern of interlocking and alternating
teeth extending around the tubular body, the pattern repeating from
a distal region to a proximal region of the length of the tubular
body, wherein each tooth of the interlocking and alternating teeth
comprises a head region that is wider than a base region, arranged
so that the head regions alternate with base regions radially
around the tubular body, so that the tubular body bends in a
direction out of a long axis of the catheter device up to a locking
radius, beyond which the tubular body does not allow further
bending in the direction; wherein each tooth of the interlocking
and alternating teeth form a tooth angle between a line extending
through a width of the head region and a line extending from the
head region and the base region; further wherein a distal portion
of the pattern of interlocking and alternating teeth comprises
teeth having an average tooth angle that is greater than an average
tooth angle of a more proximal portion of the pattern of
interlocking and alternating teeth; and wherein the distal portion
of the pattern of interlocking and alternating teeth has a pitch to
tubular body diameter ratio that is less than the pitch to tubular
body diameter ratio of the more proximal portion of the pattern of
interlocking and alternating teeth, wherein the pitch is a distance
between adjacent rows of interlocking and alternating teeth along
the long axis of the tubular body.
19. A bend-limited catheter device having a length extending in a
long axis, the device comprising: a tubular body having one or more
cut-out kerfs forming a pattern of interlocking and alternating
keystone-shaped teeth extending around the tubular body, the
pattern repeating from a distal region to a proximal region of the
length of the tubular body, wherein each keystone-shaped tooth of
the interlocking and alternating keystone-shaped teeth comprises a
head region that is wider than a base region, arranged so that the
head regions alternate with base regions radially around the
tubular body, so that the tubular body bends in a direction out of
a long axis of the catheter device up to a locking radius; wherein
each keystone-shaped tooth of the interlocking and alternating
keystone-shaped teeth form a tooth angle between a line extending
through a width of the head region and a line extending from the
head region and the base region; further wherein a distal portion
of the pattern of interlocking and alternating keystone-shaped
teeth that extends more than 2 cm along the length of the long axis
comprises keystone-shaped teeth having a tooth angle that is
between 61-84 degrees, and a proximal portion of the pattern of
interlocking and alternating keystone-shaped teeth that extends
more than 2 cm along the length of the long axis comprises
keystone-shaped teeth having a tooth angle that is between 30 to 60
degrees; and wherein the distal portion of the pattern of
interlocking and alternating keystone-shaped teeth has a pitch to
tubular body diameter ratio that is between 0.09 and 0.30 and a
pitch to tubular body diameter ratio of the more proximal portion
of the pattern of interlocking and alternating keystone-shaped
teeth is between 0.30 and 0.90, wherein pitch is a distance between
adjacent rows of interlocking and alternating teeth along the long
axis of the tubular body and the tubular body diameter is the
diameter of the tubular body transverse to the adjacent rows of
interlocking and alternating teeth.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 16/273,135, filed Feb. 11, 2019, titled
"BEND-LIMITED CATHETERS," now U.S. Patent Application Publication
No. 2019/0247622, which claims priority to U.S. Provisional Patent
Application No. 62/629,069, titled "SUPPORTIVE CATHETER," filed
Feb. 11, 2018 and U.S. Provisional Patent Application No.
62/651,049, titled "SUPPORTIVE CATHETER," filed on Mar. 30, 2018,
each of which is herein incorporated by reference in its
entirety.
INCORPORATION BY REFERENCE
[0002] All publications and patent applications mentioned in this
specification are herein incorporated by reference in their
entirety to the same extent as if each individual publication or
patent application was specifically and individually indicated to
be incorporated by reference.
FIELD
[0003] Catheter devices and methods for using them for insertion
into the body during medical procedures that are loose and flexible
up to a predetermined locking angle that avoid kinking, prolapse
and kickback. More particularly, described herein are flexible
tubular catheters, including guide catheters and balloon catheters,
guide catheters, drug infusion catheters, and the like, as well as
methods of using and making them.
BACKGROUND
[0004] Catheters are tubular devices that may be used in the
medical field for numerous applications. It is generally desirable
to obtain a maximum torsional rigidity while retaining a
satisfactory longitudinal flexibility and stiffness without
kinking. These features may allow the orientation of the catheter
to be manipulated so that the catheter can be guided through small
body vessels and cavities. These features may also prevent any
kinking, and may provide the catheter with enough "push" or
stiffness so as to prevent the catheter from wrinkling or folding
back on itself during this process. The specific nature of these
characteristics may vary depending on the specific application for
which the catheter is being used. It may also be beneficial to
provide a relatively small outside diameter and a lumen or an
inside diameter as large as possible.
[0005] Catheters (with our without guide wires) may be used both as
a diagnostic tool and in the treatment of diseases. One such
diagnostic procedure is cardiac catheterization which is a widely
performed procedure, being used for assessment of coronary artery
disease. Other uses are neurologic uses, radiologic uses,
electrophysiologic uses, peripheral vascular uses, etc. One example
of a treatment use is the use of balloon catheters in dilation
procedures to treat coronary disease. Dilation procedures rely upon
the use of a catheter for injection of contrast and delivery of
guidewires and dilation catheters to the coronary artery or other
arteries. An example of the use of guide wires is for Percutaneous
Transluminal Coronary Angioplasty (PTCA) balloons and for guiding
diagnostic catheters through the arteries and to body organs.
[0006] The catheters and guide wires used in these and other
procedures must have excellent torque characteristics, and must
have the requisite flexibility. In addition, it is important that
catheters and guidewires provide sufficient longitudinal support
for "pushing" of items through the arteries and other vessels such
as when feeding the balloon portion of an angioplasty catheter
through the arteries. Unless there is sufficient stiffness, the
catheter or guidewire will wrinkle or fold back on itself.
Catheters should ideally have sufficient torque such that they do
not buckle when being manipulated. Flexibility may be important so
that the catheter can be manipulated into the varying arterial
branches encountered by the catheter.
[0007] Prior art catheters are typically made of flexible materials
which are reinforced such that the resulting composite catheter
approximates the desired characteristics. In alternative
approaches, guide wires are used in conjunction with catheters to
assist in manipulating and moving the catheters through the
arterial system in the body. Described herein are catheters are
highly flexible, while maintaining stability, preventing kickback
and resisting prolapse and kinking.
SUMMARY OF THE DISCLOSURE
[0008] Described herein are bend-limited catheter apparatuses,
e.g., devices and systems, and methods of using them to perform a
medical procedure. In general, the apparatuses described herein may
include an elongate tubular body that includes one or more cut-out
kerfs forming a pattern of interlocking teeth that are arranged in
rings (and/or one or more spiral patterns) around the perimeter of
the elongate tubular body. The pattern of interlocking teeth is
configured, as described in greater detail herein, to provide the
catheter with a high degree of flexibility in bending, while
permitting the device to lock at a locking diameter (or locking
radius) when the relevant portion of the catheter bends to a
minimum locking angle, or minimum locking angle per unit length
corresponding to the locking diameter, beyond which no further
bending is permitted. The cut-out kerf(s) may be sealed, e.g., by a
compressible material, such as a polymer, so that the catheter
walls are fluid-tight, which may be referred to herein as a jacket
or seal.
[0009] Generally, the bend-limited catheters described herein may
be configured to be highly flexibility until bent to the locking
bend angle. In some variations the portion(s) of the catheter
including the pattern of interlocking teeth arranged radially
around the perimeter and extending down the length of the tubular
body may be loose, or floppy, when initially bending from the
straight, unbent configuration until bent to the locking bend
angle, preventing further bending. In addition, the bend-limited
catheters described herein may be thin (e.g., have a small wall
thickness) and the pattern of interlocking teeth may be configured
so that the catheters are highly smooth, while remaining lockable
and highly flexible.
[0010] These features (e.g., smoothness, lockability and
flexibility) may be achieved in a thin-walled, e.g., metal or rigid
polymeric, tube by forming the pattern of interlocking teeth in
which each tooth has dimensions, including tooth angle, tooth
height, tooth spacing (e.g., pitch, such as pitch/catheter
diameter), and tooth number that increase smoothness, permitting a
high level of flexibility without reducing the strength of the
catheter under bending (including compressive) loads. The catheters
described herein typically have an outer and inner smoothness that
permits the use of inserted devices without risking snagging or
cutting. Smoothness of these bend-limited catheters may be, at
least in part, a function of the low pitch angle (and small
backbone region), as well as the number of teeth; a larger number
of smaller, and/or shorter teeth may provide a smoother surface.
Unfortunately, smaller number and/or heights for the interlocking
teeth typically results in lower flexibility and may decrease the
strength of the catheter. In general, the larger the pitch, or the
spacing between adjacent rows/spirals of interlocking teeth along
the length of the catheter, which may include the height of the
teeth in the length of the catheter and the backbone spacing
between adjacent rows/spirals, may generally increase flexibility
while reducing smoothness (particularly where the contribution of
backbone spacing to the pitch is small, e.g., less than 50%) and
may permit a larger locking diameter. Thus, described herein are
ranges of values that may balance these often conflicting
properties to provide bend-limited catheters that may be used for a
variety of medical uses, including neurovascular and cardiovascular
uses.
[0011] Any of the bend-limited catheters described herein, which
may be referred to herein as bend-limited catheter apparatuses or
bend-limited catheter devices, may include a tubular body having
one or more cut-out kerfs forming a pattern of interlocking and
alternating teeth extending around the tubular body, wherein each
tooth of the interlocking and alternating teeth comprises a head
region that is wider than a base region, arranged so that the head
regions alternate with base regions radially around the tubular
body, so that the first region bends in a direction out of a long
axis of the catheter device up to a locking radius, beyond which
the tubular body does not allow further bending in the direction.
The pattern of interlocking and alternating teeth may extend along
the entire length of the tubular body, or just along one or more
regions (e.g., a first region, a second region, a third region,
etc.) of the length of the tubular body. In variation in which
multiple regions along the length of the tubular body include a
pattern of interlocking and alternating teeth, the same pattern may
be used or different patterns may be used, which may provide
different regions having different smoothnesses, flexibilities,
and/or locking bend angle(s). When the bend-limited catheter
includes multiple regions along the length of the tubular body are
used, these regions may be immediately adjacent to each other or
they may be separated from each other by a transition region and/or
by a region that does not include interlocking and alternating
teeth. A transition region may have a pattern of interlocking and
alternating teeth that transitions between the pattern of
interlocking and alternating teeth in the proximally-located region
of the catheter and the pattern of interlocking and alternating
teeth in the distally-located region of the catheter. The
transition may be gradual or abrupt.
[0012] Any of the catheters described herein may include a sleeve,
seal, skin, cover, sheath, or the like that may comprise a sealing
material, which may be a compressible material. extending across
the cut-out kerf. For example, the sealing material may be
laminated to the rigid tubular body (e.g., to an inner surface, an
outer surface, or both). In some variations the sealing material is
positioned between the inner and outer surfaces of the tubular
body, including within the cut-out kerf. Any appropriate sealing
material may be used. The sealing material may be a polymeric
material. In particular, the sealing material may be a thin layer,
coating, film, etc. (e.g., about 0.01 inches or less thick, about
0.009 inches or less, about 0.008 inches or less, about 0.007
inches or less, about 0.006 inches or less, about 0.005 inches or
less, about 0.004 inches or less, about 0.003 inches or less, about
0.002 inches or less, about 0.001 inches or less, etc.). The
sealing material may be a material having a relatively high (e.g.,
Shore A) durometer, such as materials having a shore A durometer of
about 60 or greater, about 65 or greater, about 70 or greater,
about 75 or greater, about 80 or greater, etc.
[0013] The interlocking and alternating teeth of the bend-limited
catheter devices described herein may be any appropriate shape or
variety of shapes, such as keystone shapes, a mushroom shapes, and
a T-shapes. In particular, the alternating teeth may be keystone
shapes. A keystone shape generally has a larger top region, which
may be flat or flattened, with sharp or rounded edges and sides
that extend at an angle relative to the top (one example of a tooth
angle) to a base, so that the base diameter is narrower than the
top. As illustrated herein the base region of a tooth forms the top
region of the alternate next tooth. Thus, the pattern of
interlocking and alternating teeth may be a pattern of interlocking
and alternating keystone-shaped teeth.
[0014] For example, a bend-limited catheter device having a length
extending in a long axis, may include: a tubular body having a
first region of one or more cut-out kerfs forming a pattern of
interlocking and alternating keystone-shaped teeth extending around
the tubular body, wherein each tooth of the interlocking and
alternating teeth comprises a head region that is wider than a base
region, arranged so that the head regions alternate with base
regions radially around the tubular body, so that the first region
bends freely in a direction out of a long axis of the catheter
device with a lateral stiffness that is less than 100 grams up to a
locking radius, beyond which the tubular body does not allow
further bending in the direction; and a sealing material extending
across the cut-out kerf.
[0015] In any of the catheters described herein, the expansion
between adjacent teeth of the interlocking and alternating teeth
may be greater than a diameter of the one or more cut-out kerfs.
Expansion between adjacent teeth may occur because the side of the
teeth, e.g., in a keystone-shaped tooth, the angled, lateral sides
of the keystone shape extending between the top and base, slide
relative to each other in approximately the long axis of the
catheter (e.g., distal to proximal). The length of the lateral
sides along which this sliding occurs may be maximized in some
variations (e.g., may be X% or greater than the height of the
tooth, where X is 20, 25, 30, 25, 40, 50, etc.). For example, the
pattern of interlocking and alternating teeth may be configured to
expand from a compressed elongate length by between about 0.005
inches and 0.085 inches per every 0.1 inch of the length of the
pattern. In some variations (or regions) having a kerf diameter of
about 0.001 inches, the pattern of interlocking and alternating
teeth may be configured to expand by about 0.002'' for each mating
set of teeth; in some variation (or regions), the pattern of
interlocking and alternating teeth may be configured to expand by
about 0.005'' for each mating set of teeth (e.g., between 0.002
inches and 0.010 inches).
[0016] The pattern of interlocking and alternating teeth may
include any appropriate number of teeth per revolution around the
diameter of the tubular body that can be fit with the pitch and
dimensions described herein. As mentioned above, it may be
beneficial to balance the number of smaller teeth (increasing
flexibility at the possible expense of minimum bend diameter) with
larger teeth (decreasing flexibility but increasing minimum bend
diameter). For example, the tubular body may comprise a minimum of
18 teeth per revolution around the diameter of the tubular body (or
between 6-70 teeth per revolution, between 12-65 teeth per
revolution, between 15-62 teeth per revolution, between 18-60 teeth
per revolution, between 20-60 teeth per revolution, 15 or more
teeth/revolution, 18 or more teeth/revolution, 20 or more
teeth/revolution, 22 or more teeth/revolution, etc.
[0017] In any of the catheters described herein, the ratio of the
pitch of the teeth to the tubular body diameter may be between 0.09
and 0.90 (e.g., between 0.1 and 0.9, between 0.12 and 0.85, between
0.10 and 0.50, etc.). The pitch may refer to the distance between
adjacent rows of interlocking and alternating teeth along the long
axis of the tubular body, including the height of the teeth; for
example, the pitch may be the height of the teeth (the distance
between the head region and the base region) and the backbone
distance before the start of the next loop of interlocking teeth in
the long axis. The diameter of the tubular body may be measured
transverse to the portion of the tubular body (e.g., transverse to
the long axis of the tubular body) at or around the location of the
interlocking teeth defining the pitch measurement. As mentioned
above, in some variations the pitch may include both the height of
the teeth and the backbone portion separating long-axis adjacent
teeth; the portion of the backbone in the pitch may be, e.g., 60%
or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or
less, 30% or less, 25% or less, 20% or less, etc. and may have a
minimum of 2%, 5%, 7%, 10%, etc. (e.g., between about 2% and 50%,
between about 5%-55%, 7.5%-50%, etc.).
[0018] In general, the pattern of interlocking and alternating
teeth may be configured so that the tooth angle is within a range
that permits the expansion area of the catheter device to be within
predefined limits, while permitting increased flexibility,
smoothness and a locking angle within a defined range. For example,
the teeth of the pattern of interlocking and alternating teeth may
form a tooth angle between a line extending through a width of the
head region (or in keystone-shaped teeth the flat or flattened top)
and a line extending from the head region and the base region
(e.g., the sides of the keystone-shaped teeth) of between about 40
degrees and about 89 degrees; in some variations between about 40
degrees and about 65 degrees (e.g., between about 40 and about 60
degrees, etc., between about 45 and about 65 degrees, between about
45-63 degrees, etc.), in some variations between about 66 and about
87 degrees (e.g., between about 68 and about 84 degrees, between
about 66 and about 82 degrees, etc.).
[0019] The tubular body may be formed of generally inflexible,
e.g., rigid, material. For example, in some variations, the tubular
body may be a rigid material such as one or more of: steel,
tungsten, and Nitinol. The tubular body may therefore be cut (e.g.,
laser cut) to form the one or more cut-out kerfs forming a pattern
of interlocking and alternating teeth. The cut-out kerf may have
any appropriate diameter, including constant or near-constant
(within +/-2%, 5%, 7.5%, etc.) diameter along its length(s), or it
may vary. In some variations, the kerf has a diameter of between
about 0.005 inches and 0.0005 inches (e.g., about 0.001 inches,
about 0.002 inches, about 0.0009 inches, etc.).
[0020] The pattern of interlocking and alternating teeth may
generally have a ratio of the bend radius to a diameter of the
tubular body of between about 1 and 25 (e.g., between about 1.5 to
22.5, etc.). The ration of the bend radius of a region of the
tubular body including the pattern of interlocking and alternating
teeth to the diameter of the kerf forming the pattern may be
between about 100 and 2100 (e.g., between about 120 and 2000, 2100
or less, 2050 or less, 2000 or less, 1950 or less, etc.).
[0021] Any of the catheter devices described herein may include one
or more balloons, e.g., inflatable balloon elements, along the
length of the device. For example, any of these catheter devices
may include an inflatable balloon on the catheter, including, but
not limited to, at or near a distal end of the catheter.
[0022] In general, the bend-limited catheter devices described
herein may be configured to have a locking radius, as mentioned
above, that is between about 0.1 cm and about 40 cm, e.g., between
about 0.2 cm and about 35 cm, between about 0.2 cm and 30 cm,
between about 0.3 cm and about 28 cm, between about 0.4 cm and
about 27 cm, between about 0.5 cm and about 26 cm, etc.
[0023] For example, a bend-limited catheter device having a length
extending in a long axis, may include: a tubular body having a
first region of one or more cut-out kerfs forming a pattern of
interlocking and alternating keystone-shaped teeth extending around
the tubular body, wherein each tooth of the interlocking and
alternating keystone-shaped teeth comprises a head region that is
wider than a base region, arranged so that the head regions
alternate with base regions radially around the tubular body, so
that the first region bends in a direction out of a long axis of
the catheter device up to a locking radius of between 0.2 cm and 30
cm, beyond which the tubular body does not allow further bending in
the direction, wherein each tooth of the interlocking and
alternating teeth form a tooth angle between a line extending
through a width of the head region and a line extending from the
head region and the base region that is between 40 and 84 degrees,
further wherein the pitch to tubular body diameter ratio of the
first region is between 0.09 and 0.90, wherein pitch is a distance
between adjacent rows of interlocking and alternating teeth along
the long axis of the tubular body; and a sealing material extending
across the cut-out kerf.
[0024] Any of the catheters, and systems including them, described
herein may include a plurality of different regions that may be
configured to have different maximum bend angles (e.g., locking
angles), flexibility and/or smoothness. In particular, it may be
particularly helpful to provide catheters having different regions
of cut-out kerfs forming one or more patterns of interlocking and
alternating teeth extending around the tubular body that have
different flexibilities and different bend angles in a distal
region as compared to a proximal region. For example, a
bend-limited catheter as described herein may include one or more
cut-out kerfs forming a pattern of interlocking and alternating
teeth extending around the tubular body that is/are configured so
that a distal region of the catheter has a higher tooth angle and
lower ratio of pitch to tube diameter as compared to a more
proximal region of the catheter (which therefore has a lower tooth
angle and a high ratio of pitch to tube diameter). This
configuration may have a distal region having a smaller bend
diameter/bend radius as compared to a distal region having a larger
bend diameter/bend radius (e.g., locking radius). The second region
may correspond to a region within the anatomy of a patient in which
the catheter is configured to be inserted; the minimum bend angle
or locking angle may correspond to the aortic region of the
anatomy, where it may be desirable to prevent excessive bending or
bucking.
[0025] For example in some variations, the catheter may be formed
of a tubular body that includes one or more cut-out kerfs forming a
pattern of interlocking and alternating teeth extending around the
tubular body and has a, e.g., first, distal region (e.g., at or
near the distal end of the catheter), extending for about 2 cm or
more (e.g., 2.5 cm or more, 3 cm or more, 5 cm or more, 7.5 cm or
more, 8 cm or more, 10 cm or more, 15 cm or more, etc.) and a
second region proximal to the distal region that extends for 2 cm
or more (e.g., 2.5 cm or more, 3 cm or more, 5 cm or more, 7.5 cm
or more, 8 cm or more, 10 cm or more, 15 cm or more, 25 cm or more,
etc.). The teeth of the first region (on average or individually)
may have a larger tooth angle than the teeth of the second region
(on average or individual). For example, the teeth of the first
region may have a tooth angle (in some variations an average tooth
angle, in some variations a maximum tooth angle, in some variations
a minimum tooth angle, in some variations a median tooth angle,
etc.) of between about 61 degrees to 84 degrees (e.g., 63 degrees
to 82 degrees, 64 degrees to 84 degrees, etc., 61 degrees or more,
62 degrees or more, 63 degrees or more, 64 degrees or more, 65
degrees or more, 66 degrees or more, etc.). The teeth of the second
region may have a tooth angle (in some variations an average tooth
angle, in some variations a maximum tooth angle, in some variations
a minimum tooth angle, in some variations a median tooth angle,
etc.) of between about 30 degrees to 64 degrees, between about 35
degrees to 62 degrees, between about 40 degrees to 60 degrees,
about 58 degrees, etc.). At the lower tooth angle (e.g., about 45
degrees, about 48 degrees, about 50 degrees, about 55 degrees,
about 58 degrees, etc.) with a 0.001'' kerf, the device may be
configured to have an additional linear expansion of 0.002'' for
each mating set of teeth. This configuration may be particularly
helpful when the catheter is configured so that the second (more
proximal region) has a larger locking diameter as compared to the
distal end region (e.g., which may keep the catheter from
prolapsing). At the larger tooth angles of the distal end of the
device, e.g., having a tooth angle of about 78 degrees, with a
0.001'' kerf, the distal region of the device has an additional
linear expansion of about 0.005'' for each mating set of teeth,
leading to greater flexibility at the distal end region. Although
the tooth angle of the distal end of the device may be as low as 40
or even 30 degrees in some variations, as these angles get smaller,
less teeth may fit around the diameter, which, while increasing
smoothness, may weaken the device and allow more loads to be
concentrated on individual teeth potentially weakening the
construct. Thus, in general, lower amounts of expansion between
teeth of the cut-out kerf pattern may improve surface smoothness.
Higher tooth angles may therefore be best utilized at the distal
end of the catheter. As the tooth angle gets higher, the tooth
height may need to increase to have a reasonable amount of tooth
engagement (e.g., along the engagement surface). As the angle gets
even larger, the tooth height may increase more, which may
increases the required pitch and minimum bend diameter. Also, the
teeth may be more likely to wedge together as this angle gets
larger.
[0026] The pitch distance may reflect the tooth height, and may
impact smoothness and flexibility. As the pitch gets smaller, the
tooth height may be reduced; reducing the pitch typically requires
a smaller tooth height. Higher pitch distances may therefore be
used in regions having a larger bend radius/bend diameter (the bend
diameter is twice the bend radius). Fewer teeth per unit length of
the catheter may increase the minimum bend diameter. Similarly,
lower pitch distances may be best utilized in regions having
smaller bend radius/bend diameters, e.g., towards the distal end of
the catheter. Lower pitch distances allow packing more teeth per
unit length and may permit greater linear expansion and smaller
bend radii. Although the relative expansion between each tooth may
be greater due to higher tooth angles, the teeth may be made
shorter (resulting in a smaller pitch) to help keep the surfaces
smooth.
[0027] The normalized ratio of pitch to tube diameter may be used
to adjust the properties of a catheter or region of a catheter to
have desired properties. For example, a pitch to tube diameter of
between about 0.009 to about 0.20 (e.g., about 0.10, about 0.12,
about 0.13, about 0.15, etc.) at the distal end of the catheter may
result in a high flexibility, and a larger pitch to tube diameter
ratio (e.g., between about 0.30 to 0.90, about 0.31 to about 0.80,
about 0.33 to about 0.70, about 0.33 to about 0.50, etc.) at the
more proximal region may increase the minimum bend radius and
prevent prolapse in larger-diameter vessel regions (or vessel
intersection regions, such as aortic regions).
[0028] For example, a bend-limited catheter device having a length
extending in a long axis, the device comprising: a tubular body
having one or more cut-out kerfs forming a pattern of interlocking
and alternating teeth extending around the tubular body, the
pattern repeating from a distal region to a proximal region of the
length of the tubular body, wherein each tooth of the interlocking
and alternating teeth comprises a head region that is wider than a
base region, arranged so that the head regions alternate with base
regions radially around the tubular body, so that the catheter
bends in a direction out of a long axis of the catheter device up
to a locking radius, beyond which the tubular body does not allow
further bending in the direction; wherein each tooth of the
interlocking and alternating teeth form a tooth angle between a
line extending through a width of the head region and a line
extending from the head region and the base region; further wherein
a proximal portion of the pattern of interlocking and alternating
teeth comprises teeth having an average tooth angle that is less
than an average tooth angle of a more distal portion of the pattern
of interlocking and alternating teeth.
[0029] For example, a bend-limited catheter device having a length
extending in a long axis may include: a tubular body having one or
more cut-out kerfs forming a pattern of interlocking and
alternating teeth extending around the tubular body, the pattern
repeating from a distal region to a proximal region of the length
of the tubular body, wherein each tooth of the interlocking and
alternating teeth comprises a head region that is wider than a base
region, arranged so that the head regions alternate with base
regions radially around the tubular body, so that the catheter
bends in a direction out of a long axis of the catheter device up
to a locking radius, beyond which the tubular body does not allow
further bending in the direction; wherein each tooth of the
interlocking and alternating teeth form a tooth angle between a
line extending through a width of the head region and a line
extending from the head region and the base region; further wherein
a distal portion of the pattern of interlocking and alternating
teeth comprises teeth having an average tooth angle that is greater
than an average tooth angle of a more proximal portion of the
pattern of interlocking and alternating teeth; and wherein the
distal portion of the pattern of interlocking and alternating teeth
has a pitch to tubular body diameter ratio that is less than the
pitch to tubular body diameter ratio of the more proximal portion
of the pattern of interlocking and alternating teeth, wherein the
pitch is a distance between adjacent rows of interlocking and
alternating teeth along the long axis of the tubular body.
[0030] For example, a bend-limited catheter device having a length
extending in a long axis, the device comprising: a tubular body
having one or more cut-out kerfs forming a pattern of interlocking
and alternating keystone-shaped teeth extending around the tubular
body, the pattern repeating from a distal region to a proximal
region of the length of the tubular body, wherein each
keystone-shaped tooth of the interlocking and alternating
keystone-shaped teeth comprises a head region that is wider than a
base region, arranged so that the head regions alternate with base
regions radially around the tubular body, so that the catheter
bends in a direction out of a long axis of the catheter device up
to a locking radius; wherein each keystone-shaped tooth of the
interlocking and alternating keystone-shaped teeth form a tooth
angle between a line extending through a width of the head region
and a line extending from the head region and the base region;
further wherein a distal portion of the pattern of interlocking and
alternating keystone-shaped teeth that extends more than 2 cm along
the length of the long axis comprises keystone-shaped teeth having
a tooth angle that is between 61-84 degrees, and a proximal portion
of the pattern of interlocking and alternating keystone-shaped
teeth that extends more than 2 cm along the length of the long axis
comprises keystone-shaped teeth having a tooth angle that is
between 30 to 60 degrees; and wherein the distal portion of the
pattern of interlocking and alternating keystone-shaped teeth has a
pitch to tubular body diameter ratio that is between 0.09 and 0.30
and a pitch to tubular body diameter ratio of the more proximal
portion of the pattern of interlocking and alternating
keystone-shaped teeth is between 0.30 and 0.90, wherein pitch is a
distance between adjacent rows of interlocking and alternating
teeth along the long axis of the tubular body and the tubular body
diameter is the diameter of the tubular body transverse to the
adjacent rows of interlocking and alternating teeth.
[0031] The distal portion of the pattern of interlocking and
alternating teeth may be configured to expand from a compressed
elongate length by between about 0.005 inches and 0.085 inches per
every 0.1 inch of the length of the pattern. Further, the proximal
portion may be configured to expand from a compressed elongate
length by less than the distal portion of the pattern of
interlocking and alternating teeth.
[0032] The distal portion may be immediately adjacent to the
proximal portion or may be separated from the proximal portion by a
spacing region (e.g., a transition region). One or more additional
portions or region, having different properties, including
different pattern(s) of interlocking and alternating teeth, may be
on the elongate body, including proximal to the proximal
region.
[0033] As mentioned above, the distal portion of the pattern of
interlocking and alternating keystone-shaped teeth may extends 2 cm
or more along the length of the long axis (e.g., about 4 cm or
more, about 5 cm or more, about 6 cm or more, about 10 cm or more,
etc.). The proximal portion of the pattern of interlocking and
alternating keystone-shaped teeth may extend 2 cm or more (e.g., 3
cm or more, 4 cm or more, 5 cm or more, 10 cm or more, etc.) the
length of the long axis.
[0034] The distal portion of the pattern of interlocking and
alternating teeth may have a pitch to tubular body diameter ratio
that is between, e.g., 0.09 and 0.30 and a pitch to tubular body
diameter ratio of the more proximal portion of the pattern of
interlocking and alternating keystone-shaped teeth that is between,
e.g., 0.30 and 0.90.
[0035] In some variations, the distal portion of the pattern of
interlocking and alternating teeth may comprise 20 or more teeth
per revolution around the diameter of the tubular body, and wherein
the proximal portion of the pattern of interlocking and alternating
teeth may comprise between 6-20 teeth per revolution around the
diameter of the tubular body.
[0036] As mentioned above, the teeth may each form a keystone
shape. The one or more cut-out kerfs may have a diameter of between
0.0005 and 0.002 inches (e.g., about 0.001 inches). The tubular
body may comprises one or more of: steel, tungsten, and
Nitinol.
[0037] Any of these devices may include a sealing material
extending across the cut-out kerf, e.g., laminated to the inside
and/or outside of the rigid tubular body. Any of these devices may
include an inflatable balloon on the catheter.
[0038] The locking radius of the distal portion of the pattern of
interlocking and alternating teeth may be more than 15% smaller
than the locking radius of the proximal portion of the pattern of
interlocking and alternating teeth. For example, the locking radius
of the proximal portion of the pattern of interlocking and
alternating teeth may be between 15 cm and 35 cm.
[0039] Also described herein are methods of using any of the
devices described herein. In general, these methods typically
include inserting the catheters using a guide devices (e.g.,
guidewire or guide catheter) within the lumen of the bend-limited
catheter, which may provide sufficient stiffness so that it can be
driven distally into the patient. The high flexibility of the
catheter, particularly the distal end intermediate regions) may
provide a high degree of tracking over the guidewire/guide
catheter. Once in position, the guidance device may be removed from
the lumen of the catheter, and the catheter may be advanced
distally; because it is so `floppy`, particularly at the distal and
intermediate region, the catheter will curve within (and in some
cases against the vessel walls) and lock in place, preventing the
distal end of the catheter from moving much. The catheter may bend
only to the locking bend angle, at which point it will lock in
position, preventing buckling and/or kickback and/or prolapse
within the vessel. Thereafter, one or more tools (other catheters,
scopes, etc.) may be delivered through the catheter to the target
tissue at the distal end and force applied against the catheter,
even in compression, may not substantially move the distal end of
the catheter and/or kink or prolapse the catheter.
[0040] Thus, a method of providing catheter access to a target
region of a vessel within a patient's body using any of the
apparatuses described herein may include: advancing a bend-limited
catheter device over a guidewire or guide catheter into the vessel
until the distal end of the bend-limited catheter device is
adjacent to the target region, wherein the bend-limited catheter
comprises a tubular body having one or more cut-out kerfs forming a
pattern of interlocking and alternating teeth extending around the
tubular body, wherein each tooth of the interlocking and
alternating teeth comprises a head region that is wider than a base
region, arranged so that the head regions alternate with base
regions radially around the tubular body, so that the tubular body
bends freely in a direction out of a long axis of the catheter
device up to a locking radius, beyond which the tubular body does
not allow further bending in the direction; removing the guidewire
at least partially out of the bend-limited catheter; and advancing
the proximal end of the bend-limited catheter so that the
bend-limited catheter locks within the vessel by bending to the
locking radius without moving the distal end of the bend-limited
catheter from the target region. Any of these methods may include
positioning the guidewire or guide catheter into the vessel. Any of
these methods may also include inserting a treatment device (e.g.,
scope, thrombecomy apparatus, stent, etc.) through the bend-limited
catheter to the target region.
[0041] For example, described herein are methods of providing
catheter access to a target region of a vessel within a patient's
body, the method comprising: advancing a bend-limited catheter
device over a guidewire or guide catheter into the vessel until the
distal end of the bend-limited catheter device is adjacent to the
target region, wherein the bend-limited catheter comprises a
tubular body having a first region of one or more cut-out kerfs
forming a pattern of interlocking and alternating keystone-shaped
teeth extending around the tubular body, wherein each tooth of the
interlocking and alternating keystone-shaped teeth comprises a head
region that is wider than a base region, arranged so that the head
regions alternate with base regions radially around the tubular
body, so that the first region bends freely in a direction out of a
long axis of the catheter device up to a locking radius, beyond
which the tubular body does not allow further bending in the
direction; removing the guidewire at least partially out of the
bend-limited catheter; and advancing the proximal end of the
bend-limited catheter so that the bend-limited catheter locks
within the vessel by bending the first region to the locking radius
without moving the distal end of the bend-limited catheter from the
target region.
[0042] For example, a method of providing catheter access to a
target region of a vessel within a patient's body may comprise:
advancing a bend-limited catheter device over a guidewire or guide
catheter into the vessel until the distal end of the bend-limited
catheter device is adjacent to the target region, wherein the
bend-limited catheter comprises a tubular body having a first
region of one or more cut-out kerfs forming a pattern of
interlocking and alternating teeth extending around the tubular
body, wherein each tooth of the interlocking and alternating teeth
comprises a head region that is wider than a base region, arranged
so that the head regions alternate with base regions radially
around the tubular body, so that the first region bends freely in a
direction out of a long axis of the catheter device up to a locking
radius, beyond which the tubular body does not allow further
bending in the direction; removing the guidewire at least partially
out of the bend-limited catheter; and advancing the proximal end of
the bend-limited catheter so that the bend-limited catheter locks
within the vessel by bending the first region to the locking radius
without moving the distal end of the bend-limited catheter from the
target region, wherein the first region of the tubular body of the
bend-limited catheter bends freely with a lateral stiffness for a
distal 10 cm of the catheter that is less than 50 grams in a
direction out of a long axis of the catheter device up to the
locking radius.
[0043] The tubular body of the bend-limited catheter may bend
freely in a direction out of a long axis of the catheter device up
to the locking radius of between, e.g., about 0.2 and 32 cm (e.g.,
about 0.2 and 30 cm, about 0.3 cm and about 29 cm, about 0.3 and
about 28 cm, about 0.4 and about 27 cm, about 0.4 and about 26 cm,
etc.).
[0044] The tubular body of the bend-limited catheter may bend
freely with a lateral stiffness for a distal 10 cm (or more) of the
catheter that is 100 grams or less (e.g., 150 g or less, 100 g or
less, 75 g or less, 50 g or less, etc.) in a direction out of a
long axis of the catheter device up to the locking radius. For
example, the lateral stiffness of the distal 10 cm or more of the
catheter may be 125 g or more (e.g., 150 g or greater, 175 g or
greater, 200 g or greater, 250 g or greater, 275 g or greater, 300
g or greater, 325 g or greater, 350 g or greater, etc.) when the
catheter is bent beyond the locking radius.
[0045] The pattern of interlocking and alternating teeth and the
cut-out kerf may be configured so that the tubular body expands in
the long axis from a compressed length to a maximally expanded
length by between about 0.005 inches per every 0.1 inch of the
length of the pattern of interlocking and alternating teeth and
0.085 inches per every 0.1 inch of the length of the pattern of
interlocking and alternating teeth, as described above.
[0046] In any of the devices and methods described herein, the
pattern of interlocking and alternating teeth may extend helically
around the tubular body; alternatively the pattern may comprise a
plurality of adjacent rings that extend around the tubular
body.
[0047] Any of these methods may include compressing a sealing
material extending across the cut-out kerf when advancing the
proximal end of the bend-limited catheter to bend to the locking
radius. The sealing material may prevent fluid from passing between
the outside and the inside of the tubular member. The sealing
material may be laminated to the rigid tubular body.
[0048] In some variations, as will be described in greater detail
below, the bend-limited catheter may be a non-uniformly
bend-limited catheter. Rotating the catheter from the proximal end
may adjust the locking radius of the catheter and/or may otherwise
assist in locking the catheter in position within the vessel.
[0049] Any of the methods described herein may include anchoring
the distal end of the catheter near the target region. For example,
the distal end may be anchored in position by inflating a balloon
on the catheter (e.g., at or near a distal end of the catheter. In
some variations, the distal end of the catheter may be held in
position securely even without a separate anchor, as described
above.
[0050] In general, the pattern of interlocking and alternating
teeth may comprise a plurality of keystone-shaped interlocking and
alternating teeth.
[0051] The bend-limited catheter apparatuses described herein may
therefore freely permit bending of the catheter with very little
(e.g., negligible) force, even when jacketed, until the catheter is
bent to the locking bend angle, beyond which it is locked, and
prevents bending. As mentioned above, in some variations, the
pattern of interlocking teeth formed by the cut-out kerf(s) is
configured so that one or more directions of bending has a
different (e.g., smaller or larger) locking diameter and therefore
locking bend angle.
[0052] For example, a non-uniformly bend-limited catheter device
having a length extending in a long axis may include: a tubular
body formed of a rigid material having one or more cut-out kerfs
forming a pattern of interlocking and alternating teeth extending
around the tubular body, wherein each tooth of the interlocking and
alternating teeth each comprise a head region that is wider than a
base region, arranged so that the head regions alternate with base
regions radially around the tubular body, so that the tubular body
bends freely out of the long axis up to a locking radius, beyond
which the tubular body does not allow further bending; wherein each
tooth of the interlocking and alternating teeth form a tooth angle
between a line extending through a width of the head region and a
line extending from the head region and the base region, further
wherein the tooth angles of the interlocking and alternating teeth
vary radially around the tubular body so that the locking radius of
the potion of the length of the tubular body varies radially around
the tubular body.
[0053] Any of the catheter features described above may be used as
part of a non-uniformly bend-limited catheter.
[0054] In some variations, the tooth angles of the non-uniformly
bend-limited catheter may vary between 10 degrees and 89 degrees
(e.g., between 30 and 87 degrees, between 40 and 84 degrees, etc.).
The pattern of interlocking and alternating teeth and the cut-out
kerf may be configured so that the tubular body expands in the long
axis from a compressed length to a maximally expanded length by
between about 0.005 inches per every 0.1 inch of the length of the
pattern of interlocking and alternating teeth and 0.085 inches per
every 0.1 inch of the length of the pattern of interlocking and
alternating teeth.
[0055] In any of these variations, the distance between the head
region and the base region of the teeth may vary radially around
the tubular body.
[0056] As mentioned above, the tubular body may comprise a metal or
rigid polymeric material (e.g., one or more of: steel, tungsten,
and Nitinol). The pattern of interlocking and alternating teeth may
extend helically around the tubular body and/or may include a
plurality of adjacent rings arranged along the length of the
tubular body. Any of these devices may include a sealing material
extending across the cut-out kerf, e.g., laminated to an outer,
inner or both surfaces of the rigid tubular body. The sealing
material may have a Shore A durometer hardness of greater than 75
(e.g., between 80 and 100), but may be relatively thin (typically
thinner than the thickness of the tubular body).
[0057] As mentioned above, the teeth may be keystone-shaped teeth
(e.g., may each form a keystone shape). Alternatively, in some
variations, the teeth may each form one of: a keystone shape, a
mushroom shape, and a T-shape.
[0058] The locking radius may be between about 0.2 cm and 32 cm
(e.g., between about 0.2 cm and about 30 cm, between about 0.4 cm
and about 29 cm, between about 0.5 cm and about 28 cm, etc.).
[0059] Any of the devices described herein may include a second
region of the length of the tubular body that comprises a second
one or more cut-out kerfs forming a second pattern of interlocking
and alternating teeth extending around the tubular body, so that
the second region of the tubular body bends freely out of the long
axis up to a second locking radius, beyond which the tubular body
does not allow further bending. One or more additional regions may
also be included. The second (or more) regions may be non-uniformly
bend-limited regions (e.g., having a varying bend angle and/or
pitch), or they may be uniform bend-limited regions.
[0060] The locking radius of the first region may be different from
the second locking radius at one more positions radially around the
tubular body.
[0061] For example, a non-uniformly bend-limited catheter device
having an elongate length extending in a long axis may include: a
tubular body formed of a rigid material having a cut-out kerf
forming a pattern of interlocking and alternating teeth extending
around the tubular body, wherein the interlocking and alternating
teeth each comprise a head region that is wider than a base region,
arranged so that the head regions alternate with base regions
radially around the tubular body; wherein the pattern of
interlocking and alternating teeth and the cut-out kerf are
configured so that the tubular body expands in the long axis from a
compressed length to a maximally expanded length by between about
0.005 inches per every 0.1 inch of the length of the pattern of
interlocking and alternating teeth and 0.085 inches per every 0.1
inch of the length of the pattern of interlocking and alternating
teeth, so that the tubular body bends freely out of the long axis
up to a locking radius, beyond which the tubular body does not
allow further bending; further wherein each tooth of the
interlocking and alternating teeth form a tooth angle between a
line extending through a width of the head region and a line
extending between the head region and the base region, wherein the
tooth angles of the interlocking and alternating teeth vary
radially around the perimeter of the tubular body, so that the
locking radius varies around the perimeter of the tubular body; and
a sealing material extending across the cut-out kerf.
[0062] As mentioned above, the distance between the head region and
the base region of the teeth may vary radially around the tubular
body. The device may include a second region of the length of the
tubular body that comprises a second one or more cut-out kerfs
forming a second pattern of interlocking and alternating teeth
extending around the tubular body, so that the second region of the
tubular body bends freely out of the long axis up to a second
locking radius, beyond which the tubular body does not allow
further bending.
[0063] The first locking radius may be different from the second
locking radius at one more positions radially around the tubular
body.
[0064] For example, a non-uniformly bend-limited catheter device
having an elongate length extending in a long axis may include: a
tubular body formed of a rigid material having a cut-out kerf
forming a pattern of interlocking and alternating teeth extending
around the tubular body, wherein the interlocking and alternating
teeth each comprise a keystone shape having a flattened head region
that is wider than a base region, arranged so that the flattened
head regions alternate with base regions radially around the
tubular body; wherein the pattern of interlocking and alternating
teeth and the cut-out kerf are configured so that the tubular body
bends freely out of the long axis up to a locking radius, beyond
which the tubular body does not allow further bending; further
wherein each tooth of the interlocking and alternating teeth form a
tooth angle between a line extending through a width of the
flattened head region and a line extending between the flattened
head region and the base region, wherein the tooth angles of the
interlocking and alternating teeth vary radially around the
perimeter of the tubular body, so that the locking radius varies
around the perimeter of the tubular body; and a sealing material
extending across the cut-out kerf.
[0065] Also described herein are methods of providing catheter
access to a target region of a vessel within a patient's body using
any of the non-uniformly bend-limited catheters described above.
For example, a method may include any of the steps described above
for use with a bend-limited catheter but may further include
rotating the proximal end of the catheter before or during the
application of force to advance the proximal end of the catheter
after removing the guide wire/guide catheter. This may allow the
user to select or otherwise control the bend angle of the catheter
apparatus in the lumen of the patient's body by orienting the
non-uniformly bend-limited catheter so that the device
preferentially bends in the selected direction out of the long axis
(where the locking angle varies along the radial orientation of the
device). The user may feel, via tactile feedback, the locking
position of the catheter within the vessel, e.g., by feeling
resistance to bending when advancing the catheter distally, as
described.
[0066] For example, a method may include advancing a non-uniformly
bend-limited catheter device over a guidewire or guide catheter
into the vessel until the distal end of the bend-limited catheter
device is adjacent to the target region, wherein the non-uniformly
bend-limited catheter comprises a tubular body having one or more
cut-out kerfs forming a pattern of interlocking and alternating
teeth extending around the tubular body, wherein each tooth of the
interlocking and alternating teeth comprises a head region that is
wider than a base region, arranged so that the head regions
alternate with base regions radially around the tubular body, so
that the tubular body bends in a direction out of a long axis of
the catheter device up to a locking radius, beyond which the
tubular body does not allow further bending in the direction;
rotating the bend-limited catheter to adjust the locking radius;
removing the guidewire at least partially out of the bend-limited
catheter; and advancing the proximal end of the bend-limited
catheter so that the bend-limited catheter locks within the vessel
by bending to the locking radius without moving the distal end of
the bend-limited catheter from the target region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] The novel features of the invention are set forth with
particularity in the claims that follow. A better understanding of
the features and advantages of the present invention will be
obtained by reference to the following detailed description that
sets forth illustrative embodiments, in which the principles of the
invention are utilized, and the accompanying drawings of which:
[0068] FIG. 1 is a an example of pattern (e.g., a keystone pattern)
of interlocking and alternating teeth extending helically around
the tubular body, wherein the interlocking teeth each comprise a
head region that is wider than a base region, arranged so that the
head regions alternate with base regions radially around the
tubular body. The values provided for the dimensions (e.g.,
lengths, widths, angles, etc.) shown in this figure, and all of the
following figures, unless specifically indicated otherwise, are
examples only, and may be +/-1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%,
50%, 75%, 100%, etc.
[0069] FIG. 2A in an enlarged view of a keystone-shaped pattern
similar to that shown in FIG. 1.
[0070] FIG. 2B is an enlarged view of another example of a
keystone-shaped pattern similar to that shown in FIG. 1.
[0071] FIG. 3 is an enlarged view of a keystone-shaped pattern
similar to that shown in FIG. 1.
[0072] FIG. 4A is an example of one variation of a portion of a
bend-limited catheter device as described herein, shown compressed
along its length.
[0073] FIG. 4B shows the portion of the bend-limited catheter
device of FIG. 4A expand from a compressed elongate length.
[0074] FIG. 4C shows the portion of the catheter device of FIGS. 4A
and 4B bent to a locking angle.
[0075] FIG. 5A is another example of a pattern (e.g., a T-shaped
pattern) of interlocking and alternating teeth extending helically
around the tubular body.
[0076] FIG. 5B is an enlarged view of a portion of the pattern of
FIG. 5A.
[0077] FIG. 6A shows an example of a bend-limited catheter device
that bends freely out of the long axis of the catheter device until
reaching a locking radius (at the locking bend angle), beyond which
bending is prohibited.
[0078] FIG. 6B is an example of portion of a tubular body of a
bend-limited catheter, showing a cut-out kerf forming a pattern of
interlocking and alternating teeth extending around the tubular
body of the catheter.
[0079] FIG. 6C is an example of a lateral stiffness profile for a
series of exemplary bend-limited catheters showing the lateral
stiffness along the length for the catheters. The distal ends of
the catheters have a very low stiffness for bend radiuses greater
than the locking bend radius (e.g., while bending at angles greater
than then the locking bend angle), as shown.
[0080] FIG. 7A is a table illustrating different features and
variables (including ranges) that may be incorporated into any of
the apparatuses and methods described herein.
[0081] FIG. 7B is a table illustrating different features and
variables that may be incorporated into any of the apparatuses and
methods described herein.
[0082] FIG. 8A is a graph showing an exemplary profile for
cantilever bend stiffness for a catheter apparatus as described
herein.
[0083] FIG. 8B illustrates one example of cantilever bend
stiffness.
[0084] FIG. 9A is a graph showing an exemplary profile for Euler
buckling for a catheter apparatus as described herein.
[0085] FIG. 9B illustrates one example of Euler buckling.
[0086] FIG. 10A is a graph showing an exemplary profile for torsion
resistance for a catheter apparatus as described herein.
[0087] FIG. 10B illustrates one example of torsion resistance.
[0088] FIG. 11A-11D illustrate examples of positioning and/or
operating catheters within a vasculature model (e.g., cardiac
vasculature). FIG. 11A shows an example of a catheter such as those
described herein over the aortic arch, not able to make the bend
into the (model of the) Brachial artery. FIG. 11B illustrates the
brachial artery deforming to allow the catheter to make turn/bend.
FIG. 11C illustrates an example of a catheter configured to make
the turn into the Brachial artery and resist prolapse. FIG. 11D
illustrates an example of a catheter apparatus configured without
sufficient bend liming (e.g., with a maximum bend angle greater
than a threshold) showing the catheter apparatus making the turn
into the Brachial artery, but the bend limiting does not resist
prolapse into the ascending aorta.
[0089] FIG. 12 illustrates one example of a pathway through the
vasculature for PE treatment.
[0090] FIG. 13 illustrates one example of a catheter as described
herein resisting prolapse into the descending aorta.
[0091] FIGS. 14A and 14B illustrate locking one example a catheter
apparatus as described herein within a straight section of a
vessel. FIG. 14A shows the apparatus in the vessel prior to
locking; FIG. 14B shows an example of the same catheter apparatus
after locking (by advancing distally without any guidewire or other
support element within the catheter), driving against the internal
lumen of the vessel.
[0092] FIGS. 15A and 15B illustrate locking one example a catheter
apparatus as described herein within a curved section of a vessel.
FIG. 15A shows the apparatus in the vessel prior to locking (able
to flexibly move within the vessel, including any turns/bends).
FIG. 15B shows an example of the same catheter apparatus after
locking (by advancing distally without any guidewire or other
support element within the catheter), driving against the internal
lumen of the vessel.
[0093] FIG. 16 illustrates one example of straightening of a
catheter as described herein.
[0094] FIGS. 17A-17B illustrate one example of bending/curving a
catheter as described herein.
[0095] FIG. 18 illustrates one example of a catheter apparatus as
described herein having two zones.
[0096] FIG. 19 is a graph illustrating anchor force in a vessel
comparing a catheter apparatus as described herein with a prior art
catheter.
[0097] FIGS. 20A-20B illustrate kickback that may occur in
operation of a prior art catheter when compressing the prior art
catheter.
[0098] FIGS. 21A-21B illustrate catheter apparatus as described
herein resisting kickback and/or buckling.
[0099] FIGS. 22A-22C illustrate one example of a catheter apparatus
that is configured to lock by telescoping over a distal tip
gasket.
[0100] FIG. 23 is an example of a catheter apparatus configured to
lock having a forward-facing element to prevent or inhibit backward
movement of the inner member relative to the outer member.
[0101] FIG. 24 is an example of a catheter apparatus configured to
lock having an inflatable element to prevent or inhibit backward
movement of the inner member relative to the outer member.
[0102] FIG. 25A is an example of a catheter apparatus as described
herein including at least one pull wire (shown untensioned); FIG.
25B shows the apparatus of FIG. 25A with the pull wire in
tension.
[0103] FIG. 26 is a graph illustrating how the ease of tracking the
catheter apparatuses described herein can be affected by the state
(compressed, relaxed, extended) of the apparatus, as compared to
the flexibility of any lamination on the catheter apparatus.
[0104] FIG. 27 is a graph illustrating how bend limiting can be
affected by the state of the catheter apparatus (e.g., compressed,
relaxed, extended) in a laminated catheter.
[0105] FIG. 28 illustrates how compression resistance of the
catheter apparatus can be affected by the state (e.g., compressed,
relaxed, extended) during in a laminated catheter.
[0106] FIG. 29A schematically illustrates operation of one example
of a catheter apparatus with multiple balloons, not inflated. These
balloons may passively follow the geometry of catheter.
[0107] FIG. 29B shows the catheter apparatus of FIG. 29A with the
balloons inflated. The longer balloon on the left encourages the
catheter to straighten, while the shorter balloon on the right
encourages bending.
[0108] FIG. 30 shows another example of a catheter apparatus as
described herein, including a cut-away region.
[0109] FIG. 31 shows an enlarged view of the catheter apparatus of
FIG. 30.
[0110] FIG. 32 is an example of a section through the exemplary
catheter apparatus of FIG. 30, in a slightly enlarged view.
[0111] FIG. 33A schematically illustrates an example of a
bend-limited catheter device having a plurality of different
regions with different bend diameters (and therefore locking bend
angles).
[0112] FIG. 33B is a schematic example of a bend-limited catheter
device having a non-spiral design or pattern of interlocking
keystone teeth radially wrapping around the perimeter of the
catheter with a variable (shown as decreasing) density of
interlocking keystone teeth along the distal to proximal length of
the catheter.
[0113] FIG. 33C is a schematic example of a bend-limited catheter
device having a spiral, e.g., helical, pattern of interlocking
keystone teeth radially wrapping around the perimeter of the
catheter with a variable (also shown as decreasing) density of
interlocking keystone teeth along the distal to proximal length of
the catheter.
[0114] FIG. 34A shows an example of a non-uniformly bend-limited
catheter that is configured to have different locking radiuses in
different directions out of the long axis of the catheter, beyond
which the tubular body does not allow further bending. The catheter
may bend freely (e.g., with little if any force required to bend
the catheter) until the catheter is bent to a curve having a bend
radius that exceeds the locking radius (e.g., then the bend angle
is greater than or equal to the locking bend angle); in FIG. 34A
the locking radius (and therefore the locking bend angle) is
greater in the north direction than any other direction out of the
long axis of the catheter.
[0115] FIG. 34B is an example of a keystone-shaped pattern (showing
the top or north side of the catheter) that is non-uniform around
the perimeter of the catheter, arranged so that each tooth of the
interlocking and alternating teeth shown forms a tooth angle
between a line extending through a width of the head region (e.g.,
the flattened top of the keystone-shaped tooth) and a line
extending from the head region and the base region (the angled-in
wall(s) of the keystone-shaped tooth), and the tooth angles of the
interlocking and alternating teeth vary radially around the tubular
body so that the locking radius of the potion of the length of the
tubular body varies radially around the tubular body.
[0116] FIG. 35A is an example of a bend-limited catheter device
having multiple regions of one or more cut-out kerfs forming a
pattern of interlocking and alternating teeth extending around the
tubular body; in this example, one of the regions ("zone 2") is
configured to have a greater locking radius (and therefore the
locking bend angle) in one direction.
[0117] FIG. 35B shows curve profiles of the exemplary bend-limited
catheter of FIG. 35A illustrating the different bend locking
radiuses for the different regions in different directions or
orientations.
[0118] FIG. 35C is an example of portions of a bend-limited
catheter device such as that shown in FIG. 35A, showing different
regions along the elongate body of the catheter; the first region
is configured to have different locking radiuses around the
perimeter of the catheter (e.g., by modifying the tooth angles of
the keystone-shaped teeth), and the second region is configured to
have a uniform locking radius around the perimeter.
[0119] FIG. 36 is an example of a portion of a non-uniformly
bend-limited catheter device having different locking radiuses
around the perimeter of the catheter (e.g., by modifying the shape
and/or size of the keystone-shaped teeth.
[0120] FIG. 37 is an example of a non-uniformly bend-limited
catheter device in which the pitch between longitudinally-adjacent
teeth changes over the length of the catheter device, similar to
that shown in FIGS. 33A-33C.
DETAILED DESCRIPTION
[0121] Described herein are bend-limited catheters (e.g.,
apparatuses, including devices and systems) and methods of using
them. A bend-limited catheter as described herein is typically
freely bendable at angles greater than the locking bend angle,
e.g., when the bend radius is less than the locking bend radius;
the device will typically limit or prevent bending beyond the
locking bend angle. Thus, the device may be configured to bend
freely in a direction out of a long axis of the catheter device
without requiring a substantial amount of force, such as by
applying less than a few grams of force when bending below the
locking bend angle. For example, the lateral stiffness of the
catheter (or of a bendable but bend-limited region of the catheter)
may be less than Z grams (e.g., where Z is 150 g, 125 g, 100 g, 75
g, 50 g, etc.) when the bend angle of the region is below the bend
locking angle. This may also be described as when the bend radius
is greater than the locking bend radius. When freely bending, the
unsupported catheter may be floppy or loose. It is generally not
possible to bend the same region of the catheter more tightly than
the locking bend angle (e.g., to have a bend radius less than the
locking bend radius).
[0122] In general, the bend-limited catheters described herein may
include one or more bend-limited regions along their length, which
may have different configurations in order to have different
locking bend radiuses and locking bend angles, as compared to other
bend-limited regions along the length and/or as compared to other
regions of the same bend-limited region around the perimeter of the
catheter.
[0123] The bend-limited catheters described herein are typically
formed of a tube of rigid material, such as a metal or polymeric
material (e.g., stainless steel, tungsten, Nitinol, etc.) that may
be cut to form the bend-limited region(s). Thus, the tube of rigid
material may include one or more cut-out kerfs forming a pattern of
interlocking and alternating teeth extending around the tubular
body. Each tooth of the interlocking and alternating teeth may
comprises a head region (which may be flat or flattened) that is
wider than a base region, arranged so that the head regions
alternate with base regions radially around the tubular body. The
pattern, including the width of the kerf, the shape and dimensions
of the teeth and the spacing (the pitch and/or backbone region) may
be configured to so that the bend-limited region is freely bendable
when bent out of the long axis of the catheter (e.g., angles from
180 degrees/unbent down to the bend locking angle.
[0124] Any of these catheter devices may include a sealing
material, e.g., a material having a low durometer, such as a
polymeric material (e.g., silicones, elastomers, rubbers,
urethanes, etc.) extending across and/or into the cut-out kerf that
may prevent fluid from passing out of the lumen of the catheter.
The material properties and/or the thicknesses of the sealing
material may be selected so that the material (which may be a
sheath, coating, etc.) does not add significant resistance to
bending, particularly when the device is bent at angles greater
than the locking bend angle.
[0125] The apparatuses, including in particular the bend-limited
catheters, described herein may be used as part of any surgical
procedure, such as minimally invasive (MI) vascular procedures. A
catheter is a generally a tubular medical device that is inserted
into a body cavity, duct, space, or vessel. MI catheter procedures
are performed millions of times a year in the US. Bend-limited
catheter may provide necessary properties when performing MI
vascular procedures. Such bend-limited catheters may have a low
column stiffness initially (e.g., they may bend or buckle when
pushed until the locking ben angle is reached), but may be
torqueable. For example, these catheters may be configured to
rotate when twisted from the access point to the tip of the
catheter, even over very long lengths, e.g., 0.5 to 1.5 meters.
Further, these devices may be of extremely low profile, so that the
device have a very thin wall thickness, providing a maximum inner
diameter (ID) for MI procedures with a minimum outer diameter
(e.g., a 0.001'' to 0.025'' thick wall). The bend-limited catheter
devices described herein may typically include a bend radius that
is limited or locked to reduce or prevent excursions, kinking, etc.
Thus, these devices may function as a limiting endo-skeleton that
creates a high-confidence, highly predictable shape when used in
vascular procedure. Typically, these devices may form a locking
shape shaft, so that the distal to medial shaft shape is locking
(e.g., curved or straight shape locking, resulting in an increased
bend stiffness at a locking bend angle). In any of these
apparatuses, the locked form of the device may provide a
uni-directional friction. The device may bend and lock within the
vessel, so that the catheter OD engages the wall of the lumen as
the device bends within the vessel; the intermediate or final
catheter shaft configuration (bends) may engage with the vessel
wall(s) in order to improve positioning of the catheter tip and
prevent movement of the distal end of the catheter during use.
[0126] A bend-limited catheter (e.g., bend-limited support
catheter) as described herein may optionally include a distal tip
anchor. The catheter itself may be formed of a metallic frame
(e.g., endoskeleton) that includes the cut-out kerf region forming
the plurality of interlocking teeth. The catheter may also include
a sealing material in, on, or over the kerf cut-out region. For
example an inner and/or outer lamination, or skin, may be
included.
[0127] In some variations, the bend-limited catheters described
herein may include five or more components; unlike other catheters,
the middle reinforcement (typically a braid or coil element) is
replaced a mechanospinal element ("endoskeleton" or ES) formed of a
rigid, and in some variations metallic, tube which works in unison
with a tension element and distal friction element to create the
properties discussed above. Thus, the tubular body is typically a
rigid tubular body and may be referred to as an endoskeleton, or ES
herein.
[0128] The catheters described herein may anchor the distal end of
the catheter at or near a target site within the lumen of a vessel.
Fixation/locking of catheter tip location relative to the access
location may allow the catheter to be used to support loads,
including compression loads during operation of one or more devices
through the lumen of the deployed catheter without substantially
displacing the catheter tip. Typically, access to vascular
procedures/indications (e.g., neuro, peripheral, structural heart)
are done through femoral arterial or femoral venous vessels.
Vascular indications require small bore long length catheters
(0.021'' to 1.5'' OD range by 1.5 meters long). Peripheral vascular
MI procedure typically use larger shorter catheters (e.g., 0.065''
to 0.183'' OD). Structural heart leverages medium length catheters
(e.g., 65-90 cm), femoral artery to heart (e.g., 0.065'' to 0.23''
OD). The bend-limited catheters described herein may be used for
any of these indications.
[0129] In order to stabilize (e.g., fix or anchor) the catheter
distal tip at a target location, bend-limited catheters described
herein may lock the catheter tip relative to its target position.
The catheter tip will resist forward or backward motion (kickback).
The bend-limited catheter will therefore anchor within the conduit
(blood vessel, bile duct, urinary, bowel, fallopian tubes,
etc.).
[0130] The mechanospinal, column support portion of the device may
be made from a metallic element laser cut to create a skeletal
structure having a cut-out kerf region that is formed in to a
plurality of interlocking teeth. The skeletal structure including
these teeth may have features that allow for precise control of
column stiffness, torque transfer, bend radius limitation, and
shape locking. When the bend-limited catheter, and particularly the
region including the pattern of interlocking teeth, is loaded
(compression, tension, bending), it may respond by either
straightening or become curved. A catheter that straightens or
curves when loaded will then engage the conduit (tube) that it is
located within (e.g., within the vessel). The size of the conduit
and the amount of curvature of the conduit relative to the
inventive catheter may affect the catheter's wall engagement, such
as the tendency to anchor/resist motion. Larger conduits may
benefit from greater catheter straightening or curving.
[0131] The catheters described herein may be used in any natural
human or other animal conduit, such as a blood vessel, bile duct,
urinary, bowel, fallopian tubes, etc.
[0132] In some variations, the catheters described herein are
configured for use as one or more of: a guide catheter (e.g.,
0.088'' or larger diameter); a PE catheter (e.g., having about
0.031'' (10 F) inner); an intermediate catheter (e.g., 0.071'' ID);
a structural heart catheter (e.g., having a 0.209'' (16 F) size),
etc.
[0133] The bend-limited structures (e.g., teeth) can be created by
cutting patterns into rigid tubing. The resulting teeth structures
may allow the tube to bend. Features of the kerf and/or teeth may
engage to limit or reduce the amount of bending.
[0134] FIG. 1 shows an example of a pattern for, e.g., a laser
cutting path into a round tube, to form one or more cut-out kerfs
forming a pattern of interlocking and alternating teeth extending
around the tubular body. For this example, the 0.3294 dimension is
the perimeter of the tube, if cut open and flattened. The
B-direction is the long axis of the tube. The pattern angle 103 is
the angle relative to an axis orthogonal to the long axis. When
this pattern is cut into a tube, the cut-out teeth may allow the
tube to bend freely, at least to a locking radius (locking angle).
In this example the teeth correspond to Keystone-shaped features
(teeth) 103 that may limit the amount of bending to the locking
angle (or locking radius). During bending, the aspect of the tube
that is on the inside of an arc may or may not compress. Meanwhile,
the aspect of the tube that is on the outside of the arc will be
longer relative to the inside of the arc. This longer feature is
created by movement of the teeth relative to each other. Also,
these teeth limit the amount of bending, as described below.
[0135] FIGS. 2A and 2B illustrate examples of laser-cut tubes
having slightly different keystone-shaped patterns. In FIG. 2A, a
region similar to region "B" of FIG. 1, is shown, illustrating an
example of a pattern including a keystone shape (which is shown as
a truncated isosceles triangle, missing the top apex) that has a
tooth angle 221 (e.g., the angle between the flat region of the
head region and side wall forming the base) that is about 78
degrees, while in FIG. 2B the tooth angle 221' is shown as 58
degrees. In any of the drawings, including the engineering drawings
described herein, the dimensions (lengths, widths, angles, etc.)
are for illustration only; actual dimensions may be varied by
+/-5%, 10%, 15%, 20%, 25%, 30%, etc. of the value(s) shown).
[0136] FIGS. 2A and 2B also illustrate the spacing between the
adjacent rows of a teeth, including the pitch 215, from the start
of first row of teeth to the start of a second row of teeth, and
the backbone 219 (the space between the end of the first row of
teeth and the start of the next row of teeth along the length). The
keystone shape, and particularly the kerf width 217, 217', height
of the tooth 220, and the tooth angle 221, may be selected to set
the locking bend angle (e.g., locking bend angle per unit of
length, as described below) and/or the bend radius. FIG. 3 shows
another example of an enlarged view of a cut-out kerf region
forming a pattern of interlocking and alternating teeth 303
extending around the tubular body. The tooth angle 321 is shown in
the enlarged figure (in this example is 78 degrees), as well as the
expansion area 323 (sowing the possible expansion of the length of
the catheter by moving between points A and B for this particular
circumferential region of the pattern). The pitch of the teeth in
this example includes the height 320 of the tooth as well as the
backbone 319 (and in this example, the kerf width 317). In FIGS. 3
(as well as the examples shown in FIGS. 2A-2B) the keystone-shaped
teeth 403 include a flatten head region 330, a narrow-diameter base
region 332, and a pair of sides 333, 333'.
[0137] FIGS. 4A-4C shows another example of a laser-cut tube 401
forming a bend-limited catheter device 400. In FIG. 4A, the device
is shown resting, un-extended state, which is compressed in the
axial direction 420. As described above, the keystone-shaped teeth
403 include a flatten head region, a narrow-diameter base region,
and a pair of sides; the sides of each tooth engage and limit
extension when pulled in the proximal-to distal direction, as shown
in FIG. 4B. FIG. 4B shows the laser-cut tube 401 of FIG. 4A,
showing the catheter in expansion 422, with the ends being pulled
apart so that the pattern of interlocking and alternating teeth 403
extending around the tubular body separate. In FIG. 4B, the
catheter 400 is expanded by the expansion area of each transverse
ring (or spiral) of teeth in the pattern. Generally, for the
catheters described herein, the expansion area is greater than the
kerf diameter by greater than about 1.15.times., 1.2.times.,
1.25.times., 1.5.times., 1.75.times., 2.times., 2.25.times.,
2.5.times., 2.75.times., 3.times., 3.5.times., etc. (e.g., between
about 1.2.times. and 6.times., between about 1.2.times. and
5.75.times., between about 1.2.times. and 5.5.times., between about
1.2.times. and 5.25.times., between about 1.2.times. and 5.times.,
between about 1.2.times. and 4.5.times., between about 1.25.times.
and 4.25.times., between about 1.25.times. and 4.times., between
about 1.25.times. and 3.75.times., between about 1.2 and
3.5.times., etc.).
[0138] In FIG. 4C the catheter 400 is shown bending, showing the
compression of adjacent keystone-shaped teeth on the inner side 455
and the expansion of keystone shapes on the outer side 457. The
gaps between the keystone features close on the inside of the arc
455 while the gaps increase along the outside of the arc 457. The
keystone-shaped teeth engage and limit bending along the outside of
the arc. In FIGS. 4A-4C, the laser kerf is 0.001''. The tooth
height is 0.013'' in this example. In this example, the tooth angle
is somewhat high (e.g., 72-80 degrees), and the number of teeth per
circumference of the tube is relatively low (e.g., 12), resulting
in a surface that is less smooth than variations having a larger
number of teeth/circumference.
[0139] Although the keystone-shaped teeth shown in FIGS. 1-4C may
be preferred, other shapes, including more rounded keystone shapes,
teardrop-shapes (and particularly teardrop shapes having a
flattened head region), other such shapes may be used, including
asymmetric shapes (e.g., shapes in which the tooth has multiple
tooth angles, such as a first side having a tooth angle that is
different from the tooth angle of the other side). For tooth shapes
in which the sides are not flat or substantially straight between
the head region and the base region of the tooth (e.g., in a
teardrop or flatten-head teardrop shape, T-shapes, etc.) the tooth
angle may be the angle of an average, mead, or median line through
the side, connecting the base region to the head region.
[0140] FIGS. 5A-5B illustrate an example of a T-shaped tooth 501.
In this example, the bend angle 521 is 90 degrees, as the sides 533
are perpendicular to the diameter of the head region 530 and the
base region 532. The expansion area 517 shows the movement of the
interlocking teeth 501. The expansion area 523 is approximately the
same distance as the kerf diameter 519; the T-shaped tooth element
is restricted from moving any further in the long axis than the
kerf diameter. Thus, the expansion area is limited to the cut-out
kerf diameter in this example. The pitch 515 show is the distance
from one set of teeth to the next, along the long axis of the
tube.
[0141] FIG. 6A illustrates an example of a bend-limited catheter
601 configure (at its distal end region) to bent to a full locking
bend angle (.beta.) per unit length. The locking bend angle 609 may
be expressed as a locking bend angle per unit of length, also
referred to herein as the minimum bend angle, wherein the length
605 is the midline 603 through the bending catheter. In some cases
it may be convenient to refer to the bend angle relative to the
long axis or out of the long axis of the catheter; in FIG. 6, the
locking bend angle relative to the long axis 611 (or equivalently,
the bend angle relative out of the long axis of the catheter) is
shown as a, 610, and is 90-.beta. (e.g., 90 minus the locking bend
angle 609). The bend radius (r.sub.bend) 607 corresponding to this
minimum bend angle, for a tube having a tube diameter 613, is
shown. Generally, the bend diameter (d.sub.bend) is twice the bend
radius. The bend angle and bend radius for a particular region
(e.g., at a point on the length of the catheter) may be measured as
from a plane transversely through the catheter at that particular
region (e.g., between a first point 619 and a second point 621 at
the boundaries of the particular region) and a second plane
transversely though the catheter at a second spot.
[0142] FIG. 6B illustrates a side view of one example of a portion
of a bend-limited catheter having a pattern of interlocking and
alternating teeth (shown as keystone-shaped teeth) extending around
the tubular body. In the portion of the pattern shown, a single
cut-out kerf forms all of the interlocking and adjacent
keystone-shaped teeth, which spirals helically around the tubular
body. Alternatively or additionally, the pattern may form multiple
separate rings (e.g., each formed by a separate cut-out kerf) that
re arranged adjacent to each other (e.g., shown in FIG. 33B). The
pitch 831 of teeth between the rows of teeth (in this
helically-arranged example) is shown as the distance (along the
long axis or length of the tube) of the tooth and the backbone
region 819, which may also include the kerf diameter, as shown. The
helix angle 833 between the rows are also shown.
[0143] The bend-limited catheters descried herein may be configured
so that they are freely bendable from an unbent/straight
configuration without the application of a substantial amount of
force (e.g., less than 150 g, less than 125 g less than 100 g, less
than 75 g, less than 50 g, etc.) to bend until reaching the locking
angle. Once bent to the locking angle, the catheter may not bend
further without deforming. This may be reflected in the stiffness
of the catheter, so for bending at angles before reaching the
locking angle the stiffness is very low over the portion of the
catheter including the pattern of interlocking teeth as described
above, e.g., at the distal and/or proximal regions of the catheter;
more distal regions may be made stiffer (e.g., by adjusting the
pattern of interlocking teeth, and/or by adding stiffing layers or
elements. FIG. 6C illustrates an example of a lateral stiffness
profile for a set of exemplary catheters 651, 653, 655, 657 having
distal, and in some cases proximal, regions of increasing relative
length that are configured as a bend-limited regions. The different
lines shown represent different catheters having freely bending
distal (or distal and proximal) regions of different lengths. The
lateral stiffnesses shown in FIG. 6C were all estimated for the
bend-limited regions at angles (relative to the long axis of the
catheter) that are below the locking bend angle (e.g., at bend
radiuses greater than the locking bend radius as described in FIG.
6A), so that catheter was extremely flexible in this range. Note
that the different catheters illustrated may have different locking
bend radiuses/different locking angles, or the same locking bending
radiuses/locking angles. The stiffness may be estimated by applying
force between two supports supporting a portion of the catheter to
determine the force required to deflect the portion of the catheter
between the supports.
[0144] A number of different variables (features) may affect
performance of the devices as described herein. For example, FIGS.
7A and 7B are tables illustrating some of these. Generally,
numerous variables influence the mechanical characteristics of the
catheters described herein, including the patterned regions. FIGS.
7A-7B identify many of these variables, and provide some insight in
how they may affect the properties of the catheter. As discussed
above, these bend-limited catheter may include one or more
different bend-limiting regions having a lock out angle along the
length of the catheter. The bend limiting regions may be covered by
an outer skin lamination (e.g., sleeve, seal, skin, cover, sheath,
or the like) that may be applied on an outer, inner or both outer
and inner surfaces. This lamination may create additional support
while also creating spring back to original shape. As mentioned
above, the cover may be particular thin, though it may have a
higher durometer (e.g., durometer of greater than 75 Shore A, e.g.,
between about 80-100). Lamination may influence the bending shapes,
bias, and limits. Some of these variables are described in FIGS.
7A-7B. Some of these variables are further described in the
empirically measured graphs of FIGS. 8A-10B.
[0145] For example, the catheters described herein may be made of
stiff ("stiffer") materials such as tungsten, steel (stainless
steel), or other metals, including shape memory metals (Nitinol)
and/or rigid polymers. The shape of the teeth (e.g., tooth angles)
may be adjusted to adjust the locking angle (locking radius/locking
diameter) and the expansion area per unit length. Typically larger
expansion areas (e.g., at larger tooth angles, such as between
60-87 degrees) may result in a decrease in the minimum bend radius,
providing an increase in the amount of bending, while lower
expansion areas (e.g., at smaller tooth angles, such as between 30
and 60 degrees) may have larger minimum bend radiuses, and may
decrease the amount of bending. Generally, the tooth angle may be
between 1 degree and 85 degrees, e.g., between 30 degrees (so that
the expansion area is greater than, e.g., 1.2.times., the cut-out
kerf diameter) and 87 degrees, between 35 degrees and 85 degrees,
between 40 degrees and 85 degrees, between 45 degrees and 85
degrees, etc. As will be described below, in some variations the
same catheter may include regions of different patterns of
interlocking teeth having different properties allowing for
different bending and locking angles (see, e.g., FIG. 33A,
described below). The pitch may be between 0.005 and 0.3 inches;
more generally, the ratio of the pitch per diameter of the tubular
body (e.g., outer diameter, inner diameter or average diameter) may
be between about between 0.03 and 0.90 (e.g., some regions may be
between 0.03 and 0.3, or between 0.05 and 0.3, or between 0.09 and
0.3, or between 0.3 and 1, or between 0.3 and 0.95, or between 0.3
and 0.9, etc.). The total number of tooth per circumference (tooth
per revolution) may be between 3 and 65, e.g., between 3 and 60,
between 6 and 60, between 8 and 60, between 12 and 60, between 18
and 60, between 20 and 60, between 22 and 60, 12 or more, 14 or
more 16 or more, 18 or more, 20 or more, 22 or more, etc.). The
axial width of the backbone region may be between 0.002 and 0.060
inches, or may be expressed as a percent of the pitch (e.g., 60% or
less, 50% or less, 40% or less, 30% or less, 25% or less, 20% or
less, etc.); the lower the percent of the pitch taken by the
backbone, the more teeth may be packed or the taller the teeth may
be used (allowing for larger tooth angles), which may increase
flexibility and/or bend angle. Other factors may include the
pattern angle (e.g., the angle of the line of teeth formed by the
cut-out kerf relative to the long axis of the catheter), which may
be between, e.g., 1-40 degrees, and the tooth shape.
[0146] The catheters described herein are typically thin walled,
but may have a relatively larger inner diameter (e.g., between
0.010 inches and 1.5 inches) when the outer diameter is
approximately 0.001 inches thick (e.g., between 0.0005 and 0.005
inches).
[0147] FIGS. 8A-10B illustrate various examples of physical
properties of some of the variations of the bend-limited catheters
described herein. For example, a bend-limited catheters may have a
cantilever bending stiffness, showing an inflection point define by
the increase in bending stiffness. The bend limited catheter has
locked out and bending stiffness increases significantly, as shown
in FIGS. 8A-8B. FIGS. 9A-9B and 10A-10B illustrate the invention
Euler buckling and Torsion Resistance characteristics,
respectively. The catheters described herein include a balance of
flexibility to make turns and gain access, while providing limiting
bending under compression and bends.
[0148] In use, the bend-limited catheters described herein may be
helpful in a variety of therapeutic indications, including
non-invasive and minimally-invasive surgical interventions, as they
may be used in the body, including in highly tortious anatomy such
as the neruovasculature, with high tracking over a guidewire, given
their very low stiffness when bending out of the long axis of the
catheter before reaching the locking angle (e.g., may be relatively
loose and floppy) but may lock when bending out of the long axis to
the locking angle, and may have a very high load capacity at the
locking angle without breaking, deforming or bucking. Further, and
surprisingly, driving these catheters from the proximal end (e.g.,
outside of the patient) may cause the catheter to lock up within
the patient vessels without substantially displacing the distal end
of the catheter, preventing or limiting "back out" of the catheter
from the target region. For example, FIGS. 11A-11D illustrate the
comparison of a bend-limited catheter within a tortious model of a
patient's vessel, including an aortic arch and brachial cephalic
artery. In the examples shown in FIGS. 11A and 11D the catheter
used is stiffer than the bend-limited catheters shown in FIGS. 11B
and 11C, and cannot access the target vessels. In FIG. 11A, the
target pathway 1105 is shown by the guidewire. The catheter 1107 is
not able to make the bend in the aortic arch region to track up to
this target path. FIGS. 11B and 11C show how a bend-limited
catheter having the right balance of flexibility and locking angle
may access and provide resistance to prolapse in a tight and
tortious region such as the ascending aorta and aortic valve. In
FIG. 11B, the bend-limited catheter 1109 (an example having
keystone-shaped teeth) tracks over the guidewire in the target path
1105, as shown. In FIG. 11C the guidewire has been removed, and a
load has been applied (manually, shown by holding the distal end
fixed and advancing the proximal end of the catheter, resulting in
a force 1119 that would otherwise prolapse the catheter). Rather
than prolapse into the aortic arch 1113, the catheter locks at the
locking angle 1115 shown. FIG. 11D illustrates prolapse 1122 with a
catheter 1125 that does not lock at a locking angle within the
aortic arch.
[0149] The bend-limited catheter described herein, including those
having keystone-shaped teeth, can be tuned for use in other vessels
of conduits. For instance, to reach the pulmonary artery for
pulmonary embolism treatment, a catheter must be able to gain
access through the venous system, through the right side of the
heart. FIG. 12 shows the access path to the pulmonary artery form
the right femoral vein. Arrows illustrate regions 1205, 1207 where
a bend-limited catheter may include a locking angle to resist
prolapse. FIG. 13 illustrates an example of a bend-limited catheter
1301 that include a locking angle sufficient to resist prolapse
into the descending aorta 1309.
[0150] The bend-limited catheters in various indication will
provide superior catheter support, either as a guide or stand-alone
self-support due to the inventions ability to gain access, follow
vessel curvature with essentially infinite column stiffness, and
provide essentially infinite torque-ability. The bend limited
catheters described herein may therefore resist kinking, coiling
and prolapse. Further, these devices may lock under load
compressive load (e.g., bending stiffness increase when compressed)
or by a proximal end laid out feature.
[0151] In any of the bend-limited catheters described herein the
catheter may have two or more locking (bend limiting) zones or
regions. In some variations, the catheter may include one or more
puller threads to apply compressive force to lock the catheter. For
example, the catheter may include two puller threads, as shown in
FIGS. 14A-14B. FIGS. 14A-14B illustrate locking/anchoring invention
in a straight section of a conduit.
[0152] The bend-limited catheters described herein are also
configured to lock against the walls of the vessel when a
compressive force is applied; this locking may help anchor the
devices within the vessel, and may help prevent or reduce pull back
of the distal end of the device from the target region. For
example, FIGS. 15A-15B illustrate locking/anchoring of a
bend-limited catheter in a curved conduit (e.g., vessel, body
lumen, etc.). In some variations, tip anchoring may be achieved by
having a small bore pulling element attached to the catheter distal
tip off its central axis. This may be called an actively actuated
tip anchor. A puller wire may be placed in tension, the tip then
curves until it bumps into a vessel wall of the bend limited
element locks out. Alternatively the device may be locked by
advancing proximally.
[0153] FIG. 16 illustrates puller along central axis. In some
variations the bend-limited catheter may be biased to tend to
straighten into this configuration. FIGS. 17A-17B illustrate the
use of a puller 1705 that is offset from central axis to bend
and/or lock a bend-limited catheter 1701. FIG. 18 illustrates a
catheter 1801 having two zones with different regions of actuation
(bend-limited regions, formed by two or more patterns of
alternating teeth, as described above). These zones can also have
different curving (or straightening) capabilities and may be (in
this example) actuated by two different pull wires 1805, 1805'.
Anchoring force may be measures, such as in the example shown in
FIG. 19. A bend-limited catheter 1901 was compared to typical
(commercially available) guide MI catheter 1905, and found to have
substantially lower tip movement per compressive force. The
catheters were placed in an anatomical vessel model as shown in
FIGS. 20A-20B. Catheters were introduced 2001 and the location of
the catheter tip was placed near a target site 2002; the catheter
was placed over a guidewire or guide catheter to provide the
rigidity necessary or initial placement. Once in position, the
guidewire and/or guide catheter may be removed. A compression force
2007 at the tip was applied to both catheters. The force needed to
move the tip backwards (kick back) was measured. Higher force is
preferred (translates to more tip stability and more accurate tip
location. This catheters described herein, leveraging both bend
limit and tip anchor proved superior to tip movement, i.e., the tip
required more force to move backwards 2005.
[0154] FIGS. 20A-20B shows the setup using a traditional catheter.
Compressive axial load at the distal end causes kickback within the
length of the catheter, resulting in distal tip backwards movement.
FIGS. 21A-21B shows a bend-limited catheter as described herein
having anchoring and bend-limiting features. Anchoring and bend
resistance (e.g., prolapse resistance, anti-excursion) reduces or
eliminates backwards movement of the distal tip, as shown. The
locking feature (e.g., locking angle) of the bend-limited catheter
described herein creates a stable, non-moving tip position within
the vessel. Once the tip is anchored, a second catheter can be
inserted, using, for example, telescopic catheters. Thus, a first
bend-limited catheter may act as a guide catheter. A secondary or
inner catheter may also be a bend-limited catheter.
[0155] Due to the diameter ratios of the smaller catheter within
the bend-limited outer catheter (large ID/OD), the locking may be
less effective. However the bend-limited catheters described herein
may transmit the outer bend-limited catheter's locking/anchoring to
the inner bend-limited catheter's surface. This may form a
telescoping catheter system, as shown in FIGS. 22A-22C. The inner
(small diameter) bend-limited catheter may be actively locked to
the outer bend-limited catheter, which may then produces a stable
platform for use with additional components (e.g., surgical tools).
This is illustrated in FIGS. 22A-22C, showing the locking nature of
outer bend-limited catheter relative to the inner bend-limited
catheter as a passive lock (activated by a property of the
bend-limited catheter rather than requiring active engagement by a
user). The outer (e.g., guide) bend-limited catheter tip may
include a reverse/backward sliding element, e.g., pulling the inner
bend-limited catheter backwards relative to the guide. The
directional element may allow forward motion with minimal force.
When the inner bend-limited catheter is pulled backward, the force
increases, resisting the reverse sliding force. The reveres motion
of the inner bend-limited catheter may be transferred to the outer
(larger/stiffer, stronger and locked/anchored) bend-limited
catheter as shown. The force transfer is to a larger outer
catheter. The unidirectional tip element in this invention is
accomplished using any of the examples above. FIGS. 23-24 show a
locking region in the coaxial bend-limited catheter (e.g., in the
inner bend-limited catheter) that may also be used.
[0156] FIG. 22A-22C illustrates a thin walled elastic tip taper
section (1-10 mm long) which has a decreasing diameter (ID/OD
match) to 10% smaller than the ID of a bend-limited catheter. The
taping tip creates a near one-way valve. As the inner co-axial
catheter advances forward through the outer catheter tip taper
section, the taper stretches around the inner catheter, the taper
section stretches open and the inner catheter is advanced. When the
inner bend-limited catheter is puller (direction reversed), the
taper grips the inner catheter and transfers load to the outer
bend-limited catheter, which is locked to the vessel wall, either
straightening lock or curving lock.
[0157] FIG. 23 illustrates a forward-facing filament element that
resists inner bend-limited catheter movement backwards, relative to
outer bend-limited catheter. Similarly, FIG. 24 illustrates an
inflating balloon lock/gasket design, where the balloon squeezes
the tip of the inner bend-limited catheter. This inhibits backwards
movement of the inner catheter relative to the outer bend-limited
catheter.
[0158] Alternatively or additionally, a stented valve design may be
used. For this design, a stented valve can be used to reduce or
eliminate backwards movement of the inner catheter relative to the
outer catheter. For example, the stent tends to reduce in diameter
when the distal aspect of the stent element is pulled towards the
proximal end of the stent. This stent-like feature can be
positioned at the distal end of the outer catheter, similar to
previous methods shown in FIGS. 23 and 24.
[0159] The examples of methods described below illustrate the
application of compression to a body of a bend-limited catheter to
facilitate position and orientation locking. This may maintain the
tip of the bend-limited catheter in a target distal position while
the vessel is treated. For example, in some variations, the method
may maintain or advance the proximal end position of the
bend-limited catheter to maintain a compressed state of the
bend-limited catheter; the b bend-limited catheter may be used as a
guide catheter (GC), for example. In this method, the bend-limited
catheter may be advanced through an optional sheath and to its
targeted position by pushing on proximal end of bend-limited
catheter. The bend-limited catheter can be delivered preloaded with
a supportive inner dilator catheter and/or an optional guide wire
to aid in delivery. Once the bend-limited catheter tip is at the
target location, the dilator and/or guidewire can be optionally
fully or partially removed.
[0160] The bend-limited catheter may be either maintain in the
inserted position or advanced from the proximal end of the
bend-limited catheter to remove slack and/or to compress the length
of the bend-limited catheter. An advancing or holding force applied
by the user may help force the bend-limited catheter to move into a
radius-locked configuration and/or shape, as described above. The
bend-limiting pattern of the interlocking teeth in the tubular body
of the bend-limited catheter may make the bend-limited catheter
more supportive and stiff, allowing delivery of other devices
through the bend-limited catheter without kicking back and out of
the patient.
[0161] The proximal end of the bend-limited catheter may be secured
relative to the patient by a variety of methods so the bend-limited
catheter does not uncoil from its compressed configuration. For
example, the bend-limited catheter may be secured to the patient
via a securement (e.g., tape, Velcro, suture, etc.), and/or the
bend-limited catheter may be secured to the operating table a
securement (e.g., tape, Velcro, suture, etc.). The proximal end of
the bend-limited catheter may be held by hand, or by securing the
bend-limited catheter through passive or active friction lock in
sheath already placed in the patients' blood vessel, body or
operating equipment (table, bed, etc.).
[0162] Optionally, a tightening, deflecting or compression element
connected near the distal end of the bend-limited catheter may be
used, including through a feature in the proximal end of the
bend-limited catheter. This actuation can additionally stiffen the
bend-limited catheter to create a supportive structure/tube for
delivery of other devices.
[0163] In some variations the bend-limited catheter may be operated
by distal end actuation to apply compression to the bend-limited
catheter. For example, an advance bend-limited catheter may be
positioned by pushing on proximal end of bend-limited catheter
until the distal tip is at target location; a stiffening inner
and/or outer member may be used, such as a guidewire. The position
of the proximal end of the bend-limited catheter may be maintained
relative to patient. A tightening, deflecting or compression
element connected the distal end of the bend-limited catheter may
be actuated through a feature in the proximal end of the
bend-limited catheter, which may apply compression forces between
the distal end and proximal end of bend-limited catheter,
encouraging the bend-limited catheter into a radius-locked
orientation/shape. The radius-locked orientation of the catheter
may maintain the distal positioning and may create a more
supportive structure/tube for delivery of other devices.
[0164] In some variations, a pull wire may be used to apply
compression to a bend-limited catheter. For example, a bend-limited
catheter may be advanced into position by pushing on a proximal end
until the distal tip of the bend-limited catheter is at target
location (as before a stiffening member may be used). The position
of the proximal end of the bend-limited catheter may be maintained
relative to the patient or the proximal end may be advanced.
Tension may be applied to a pull-wire coupled to the bend-limited
catheter while maintaining the position of the proximal end of the
bend-limited catheter relative to the patient (e.g., by pushing).
The pull wire may be fixed to the distal end (or a distal end
region) of the bend-limited catheter, and can be pulled from
outside the patient (as shown by example in FIG. 25A). Tension on
this pull-wire may apply a compression along the length of the
bend-limited catheter, as shown in FIG. 25B. This compression may
improve the radius-locked orientation/shape of the bend-limited
catheter. The radius-locked orientation of the bend-limited
catheter may maintain the distal positioning of the bend-limited
catheter, allowing actuation to be more effective.
[0165] The bend-limited catheters described herein may be
fabricated in a manner that modifies their properties. For example,
the extension state of the bend-limited catheter during fabrication
can affect the properties of the catheter, including trackability
(the ability of the catheter to get to the target location), bend
limiting (the ability of the catheter to resist bending and lock
out in key areas), and compression resistance (the ability of the
catheter to resist compression during use). The bend-limited
catheters described herein typically have superior control of bend
limiting and compression resistance as compared to prior art
devices, which may increase the ability to maintain distal tip
position during use.
[0166] The bend-limited catheters described herein may be in any of
three or more different states of extension prior to (and during)
the addition of sealing (e.g., lamination) materials to the inner
and/or outer surfaces of the bend-limited catheter. For example,
the catheter may be in a compressed, relaxed, or extended
configuration (or some combination of these, or intermediate
position between these, including bent/curved). This may affect the
final shape set of the bend-limited catheter. The modulus of the
sealing material (e.g., lamination) relative to that of the
spring-like tubular body may influence the properties of the
catheter.
[0167] For example, if the bend-limited catheter is laminated when
compressed, the tubular body (including the pattern of interlocking
teeth) may act like a coil spring in compression, being held in
position by an elastic in tension. When the bend-limited catheter
is laminated in a relaxed state, the tubular body and the sealing
material may act like springs in unloaded states. When the
bend-limited catheter is laminated in the extended state, the
tubular body may act like a coil spring in tension, being held in
position by a rubber tube in compression.
[0168] The amount of sealing material that protrudes into the kerf,
e.g., between the laser cut edges, may also influences the
properties of the catheter; this may be reflected in the thickness
of the sealing material. Further, a minimal amount of sealing
material within the laser cut kerf region may result when the
sealing material is applied in the compressed configuration. A
nominal amount of sealing material may be present in the kerf when
the material is applied in the relaxed configuration. This sealing
material may increase the ability of the bend-limited catheter to
bend, by compressing along the inside arcs of bends.
[0169] When the sealing material is applied in the expanded
configuration, a maximal amount of sealing material may be
laminated into the kerf. This sealing material may further increase
the ability of the bend-limited catheter to bend, by compressing
along the inside arcs of bends.
[0170] FIGS. 26, 27 and 28 for illustrate example of the effects of
applying sealing material (lamination) in various amounts within
the kerf region (e.g., applying when compressed, having little
material, when relaxed, having a moderate amount of material, or
when expanded, having the most material). These properties may
relate to one another for a particular bend-limited catheter and
sealing material combination.
[0171] In some variations, a thin-wall braided tube can be
positioned outside of the bend-limited catheter to provide bend
limiting resistance. During catheter bending, the braided tube may
increase frictional resistance against the bend-limited catheter
(e.g., the tubular body), reducing the catheter's ability to
lengthen along the outside aspect of the curve. This may limit
bending. Variables that govern relationship include: braid material
stiffness, braid material size, number of braid ends, braid angle,
braid pattern, braid "wall thickness", braid inner diameter
relative to the tubular body outer diameter, braid material profile
(round, square, etc.). Also, a braid can be designed to have
diameter "bumps" or angle changes. This facilitates focusing the
bend-limited characteristics to localized regions along the
bend-limited catheter. The braid can be loose outside the
bend-limited catheter, within the sealing material/coating (e.g.,
lamination), or sandwiched in-between the sealing coating and the
tubular body.
[0172] As mentioned above, any of these devices may include a
balloon that can be secured to the bend-limited catheter, e.g., on
the outside of the bend-limited catheter. When filled with fluid,
it may add stiffness to the catheter. This can help anchor the
distal tip of the catheter in a desired location, and/or help
resist bending in other locations. A balloon can be positioned
along the length of the bend-limited catheter, on the inside or
outside. This balloon may be positioned outside of the bend-limited
catheter, or inside of the bend-limited catheter. The balloon can
be in the shape of a straight tube, an arced tube, a straight line,
a helix, etc. This balloon does not have to be run along the entire
length of the ES, but may extend over a small region of the
catheter, nor does the balloon have to be one continuous shape, but
may contain multiple different shapes. Preferably, the balloon may
be a tubular balloon. This balloon may be actively
inflated/activated and deflated/inactivated from outside the body.
FIGS. 29A-29B illustrate one example of tubular balloons 2905, 2909
over a bend-limited catheter 2901. The uninflated balloons show in
FIG. 29A are shown inflated in FIG. 29B.
[0173] FIGS. 30-32 illustrate an alternative variation of a
bend-limited catheter in which flexible metal conduit is
miniaturized and used to form the bend-limited catheter. In this
example, flat ribbon is shaped into rings or a helix, and is formed
into a long tube, as shown. The formed shapes interact with each
other to allow and limit tube bending.
[0174] Any of the bend-limited catheters described herein may be
configured as bend-limited catheter devices having multiple
different patterns of interlocking and alternating teeth extending
around the tubular body, formed by the one or more cut-out kerf.
The pattern of interlocking and alternating teeth may repeat from a
distal region to a proximal region of the length of the tubular
body. As already described above, each tooth of the interlocking
and alternating teeth may comprise a head region that is wider than
a base region, arranged so that the head regions alternate with
base regions radially around the tubular body, so that the catheter
bends in a direction out of a long axis of the catheter device up
to a locking radius, beyond which the tubular body does not allow
further bending in the direction. Each tooth of the interlocking
and alternating teeth may form a tooth angle between a line
extending through a width of the head region (e.g. or along the
flattened head region) and a line extending from the head region
and the base region (e.g., the sides), as described above.
[0175] These devices may include a proximal pattern and a more
distal pattern that have different properties, and in particular,
have different average tooth angles and/or different ratios of
pitch to tubular body diameter. For example, the average tooth
angle of the distal region may be greater than the average tooth
angle of the more proximal region.
[0176] FIG. 33A illustrates one example of a bend-limited catheter
device having a distal (e.g., first) region 3305 that having
different properties than the more proximal 3307 (e.g., second)
region. The first region is located immediately adjacent to the
second region, though they may be separated by an intervening
region. One or more additional regions 3309 may be arranged
proximal and/or distal (or between) the first and second regions.
In some variations the distal end region 3305 may begin at the
distal end of the catheter and may extend for up to 30 or more
(e.g., up to about 20, about 22, about 23, about 24, about 25,
about 26, about 27, about 28, about 29, about 30, about 31, about
32, about 33, about 35, etc.) cm. The proximal region may be
calibrated to be in the aortic region for a neurovascular catheter,
and may extend from the distal region for another 20-35 cm (e.g.,
about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm,
about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm,
about 30 cm, etc.).
[0177] In FIG. 33A, the catheter is configured so that the distal
region has a higher flexibility and smaller locking angle (e.g.,
larger locking angle relative to the long axis of the catheter).
This may be achieved by using a pattern of interlocking and
alternating keystone-shaped teeth extending around the tubular body
for the distal portion 3305 in which the pattern of interlocking
and alternating keystone-shaped teeth may extends more than 2 cm
along the length of the long axis (e.g., between 2 and 30 cm, e.g.,
between 2-29 cm, between 3-28 cm, between 3-27 cm, between 4-26 cm,
between 4-25 cm, between 4-24 cm, between 4-23 cm, etc.) comprises
keystone-shaped teeth having a tooth angle that is between 61-84
degrees (e.g., about 78 degrees in one example). This is
illustrated in the enlarged region 3315 of FIG. 33A. The more
proximal portion 3307 of the pattern of interlocking and
alternating keystone-shaped teeth may extend more than 2 cm along
the length of the long axis (e.g., may extent between 2 and 30 cm,
e.g., between 2-29 cm, between 3-28 cm, between 3-27 cm, between
4-26 cm, between 4-25 cm, between 4-24 cm, between 4-23 cm, etc.)
may have keystone-shaped teeth having a tooth angle that is between
30 to 60 degrees (e.g., about 58 degrees in one example). This is
illustrated in the enlarged region 3317 of FIG. 33A. The distal
portion of the pattern of interlocking and alternating
keystone-shaped teeth may have a pitch to tubular body diameter
ratio that is between 0.09 and 0.30 and a pitch to tubular body
diameter ratio of the more proximal portion of the pattern of
interlocking and alternating keystone-shaped teeth is between 0.30
and 0.90.
[0178] FIGS. 33B and 33C illustrate other examples of bend-limited
catheters including multiple regions along their length (including
distal region and proximal regions) having different locking bend
angles, smoothness, and/or flexibility. For example in FIGS. 33A
and 33B, the proximal region has a much smaller pitch/tube diameter
compared to the more proximal region. FIG. 33A shows an example in
which the pattern of interlocking teeth are formed by multiple
cut-out kerfs into multiple parallel, transverse rows; FIGS. 33B
shows a single helically wound cut-out kerf forming multiple rows
of interlocking teeth.
[0179] As mentioned above, any of the devices described herein may
be non-uniformly bend-limited catheter devices that may include
regions of different locking radiuses around the perimeter of the
bend-limited region, as illustrated in FIG. 34A. Such devices may
be adjustable by rotating the catheter shaft axially, and may
therefore act as an active lock/stabilizer in a vessel. In FIG. 34,
the bend-limited catheter includes a much smaller locking bend
angle, .beta. (a much larger locking bend angle relative to the
long axis of the catheter, .alpha., as shown in FIG. 6) in the
"north" direction 3405; the east 3307, west 3311 and south 3309
directions all have similar locking bend angles, as shown,
resulting in the non-uniform bending limiting property of the
catheter. This may be achieved by adjusting the pattern of
interlocking and alternating teeth, as described herein.
[0180] The teeth (e.g., keystone-shaped teeth) may form a gradient
around the perimeter create a bend limiting element. The keystone
gradient may be engineered to produce different amounts of limiting
(bend radius bias) depending on the direction the tube is bent. A
catheter made with the gradient bias would be able to bend around
tight turns (small bend radius) and by torqueing the proximal
catheter end from 0 to less than 180 degrees (half a turn) the bend
radius limiting element would increase and the catheter would
create an adjustable locking zone (more to less bending), to
provide an adjustable locking within a vessel (e.g., wedging to
wall or tangent touch points), and/or remove the access limiting
nature of a fixed single bend limiting keystone. The locking angle
(and correspondingly, the locking diameter/locking radius) may be
tuned or adjusted in a non-uniform manner around the perimeter of
the catheter. FIGS. 34B shows an example of a portion of a cut-out
kerf pattern for a bend-limited catheter that has a non-uniform
locking bend angle around the circumference of the catheter.
[0181] In FIG. 34B, for example, the keystone-shaped teeth are
arranged in longitudinally parallel sets of teeth having different
tooth angles (and in this example, different tooth heights) that
provide for differential locking bend angles, and therefore a bias
bend configuration (e.g., bending is biased more in one direction,
e.g., north, than in other directions). In FIG. 34B, the tooth
angles at the top 3403 of the tubular body have a tooth angle
(e.g., about 40 degrees), which may be the bend angle for teeth on
the back side of the catheter (not shown). The middle region 3405
has a tooth angle of 73 degrees, which decreases for the teeth on
either side of the middle row (e.g., to 70 degrees, 65 degrees and
57 degrees, back to 40 degrees). The height of each tooth also
decreases as the teeth move away from the line of teeth
corresponding to the `north` (e.g., the middle region 3405) in the
pattern. The larger pitch of these middle teeth may allow the
contact surfaces of the sides to slide more, providing a larger
expansion area in these teeth, and therefore greater bending (e.g.,
larger locking bend angle relative to the long axis of the
catheter, .alpha.).
[0182] The bias bend design can be continuous the whole catheter
length, it can is limited zone length, it can be spread between two
zones (one more proximal), bend limits in 2 zones can be out of
phase to create an S curves like property control. For example,
FIGS. 35A-35C illustrate an example of a catheter having multiple
regions of bending limiting around their perimeter, in which at
least one of these regions has non-uniform bend limiting. FIG. 35A
shows a distal bend-limited region ("zone A") 3502 and a proximal
bend-limited region ("Zone B") 3505. In this example, the second
zone 3505 has a bend-limited bias that is oriented in the north
direction (e.g., up, as shown in FIG. 34A, e.g., at 180 degrees if
measured radially with south being 0 degrees). The proximal zone
may be uniformly bend-limited or may also be non-uniformly bend
limiting.
[0183] FIG. 34B illustrates an example of a curvature profile for a
catheter similar to that shown in FIG. 34A in which the second zone
(3505') is biased.
[0184] FIG. 35C shows an example of two regions of a catheter
including a first region 3505 that is non-uniformly bend-limited
and a second region that is uniformly bend-limited. In this
example, the first region includes different teeth angles in teeth
aligning down the long axis of the catheter, as shown. The second
region also include a pattern of interlocking and alternating
teeth, but all of these teeth having the same tooth angle around
the circumference of the catheter, as shown. In this example the
tooth height is approximately the same for all teeth; the tooth
heights in the non-uniformly bend-limited region may instead vary,
as described above.
[0185] FIGS. 36 and 37 illustrate alternative embodiments of
cut-out kerfs forming a pattern of interlocking and alternating
teeth extending around the tubular body. For example, in FIG. 36,
the height of the teeth various around the circumference of the
tubular body, which may modify the smoothing, strength, flexibility
and locking bend angle of the catheter, as described above. In FIG.
37, the pitch 3701, 3703, 3705, 3707 increases along the length
(distal to proximal) of the catheter, similar to that shown in FIG.
33C.
[0186] Any of the methods (including user interfaces) described
herein may be implemented as software, hardware or firmware, and
may be described as a non-transitory computer-readable storage
medium storing a set of instructions capable of being executed by a
processor (e.g., computer, tablet, smartphone, etc.), that when
executed by the processor causes the processor to control perform
any of the steps, including but not limited to: displaying,
communicating with the user, analyzing, modifying parameters
(including timing, frequency, intensity, etc.), determining,
alerting, or the like.
[0187] When a feature or element is herein referred to as being
"on" another feature or element, it can be directly on the other
feature or element or intervening features and/or elements may also
be present. In contrast, when a feature or element is referred to
as being "directly on" another feature or element, there are no
intervening features or elements present. It will also be
understood that, when a feature or element is referred to as being
"connected", "attached" or "coupled" to another feature or element,
it can be directly connected, attached or coupled to the other
feature or element or intervening features or elements may be
present. In contrast, when a feature or element is referred to as
being "directly connected", "directly attached" or "directly
coupled" to another feature or element, there are no intervening
features or elements present. Although described or shown with
respect to one embodiment, the features and elements so described
or shown can apply to other embodiments. It will also be
appreciated by those of skill in the art that references to a
structure or feature that is disposed "adjacent" another feature
may have portions that overlap or underlie the adjacent
feature.
[0188] Terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. For example, as used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, steps, operations, elements, components, and/or groups
thereof. As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items and may
be abbreviated as "/".
[0189] Spatially relative terms, such as "under", "below", "lower",
"over", "upper" and the like, may be used herein for ease of
description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if a device in the figures is inverted, elements
described as "under" or "beneath" other elements or features would
then be oriented "over" the other elements or features. Thus, the
exemplary term "under" can encompass both an orientation of over
and under. The device may be otherwise oriented (rotated 90 degrees
or at other orientations) and the spatially relative descriptors
used herein interpreted accordingly. Similarly, the terms
"upwardly", "downwardly", "vertical", "horizontal" and the like are
used herein for the purpose of explanation only unless specifically
indicated otherwise.
[0190] Although the terms "first" and "second" may be used herein
to describe various features/elements (including steps), these
features/elements should not be limited by these terms, unless the
context indicates otherwise. These terms may be used to distinguish
one feature/element from another feature/element. Thus, a first
feature/element discussed below could be termed a second
feature/element, and similarly, a second feature/element discussed
below could be termed a first feature/element without departing
from the teachings of the present invention.
[0191] Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and
variations such as "comprises" and "comprising" means various
components can be co-jointly employed in the methods and articles
(e.g., compositions and apparatuses including device and methods).
For example, the term "comprising" will be understood to imply the
inclusion of any stated elements or steps but not the exclusion of
any other elements or steps.
[0192] In general, any of the apparatuses and methods described
herein should be understood to be inclusive, but all or a sub-set
of the components and/or steps may alternatively be exclusive, and
may be expressed as "consisting of" or alternatively "consisting
essentially of" the various components, steps, sub-components or
sub-steps.
[0193] As used herein in the specification and claims, including as
used in the examples and unless otherwise expressly specified, all
numbers may be read as if prefaced by the word "about" or
"approximately," even if the term does not expressly appear. The
phrase "about" or "approximately" may be used when describing
magnitude and/or position to indicate that the value and/or
position described is within a reasonable expected range of values
and/or positions. For example, a numeric value may have a value
that is +/-0.1% of the stated value (or range of values), +/-1% of
the stated value (or range of values), +/-2% of the stated value
(or range of values), +/-5% of the stated value (or range of
values), +/-10% of the stated value (or range of values), etc. Any
numerical values given herein should also be understood to include
about or approximately that value, unless the context indicates
otherwise. For example, if the value "10" is disclosed, then "about
10" is also disclosed. Any numerical range recited herein is
intended to include all sub-ranges subsumed therein. It is also
understood that when a value is disclosed that "less than or equal
to" the value, "greater than or equal to the value" and possible
ranges between values are also disclosed, as appropriately
understood by the skilled artisan. For example, if the value "X" is
disclosed the "less than or equal to X" as well as "greater than or
equal to X" (e.g., where X is a numerical value) is also disclosed.
It is also understood that the throughout the application, data is
provided in a number of different formats, and that this data,
represents endpoints and starting points, and ranges for any
combination of the data points. For example, if a particular data
point "10" and a particular data point "15" are disclosed, it is
understood that greater than, greater than or equal to, less than,
less than or equal to, and equal to 10 and 15 are considered
disclosed as well as between 10 and 15. It is also understood that
each unit between two particular units are also disclosed. For
example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are
also disclosed.
[0194] Although various illustrative embodiments are described
above, any of a number of changes may be made to various
embodiments without departing from the scope of the invention as
described by the claims. For example, the order in which various
described method steps are performed may often be changed in
alternative embodiments, and in other alternative embodiments one
or more method steps may be skipped altogether. Optional features
of various device and system embodiments may be included in some
embodiments and not in others. Therefore, the foregoing description
is provided primarily for exemplary purposes and should not be
interpreted to limit the scope of the invention as it is set forth
in the claims.
[0195] The examples and illustrations included herein show, by way
of illustration and not of limitation, specific embodiments in
which the subject matter may be practiced. As mentioned, other
embodiments may be utilized and derived there from, such that
structural and logical substitutions and changes may be made
without departing from the scope of this disclosure. Such
embodiments of the inventive subject matter may be referred to
herein individually or collectively by the term "invention" merely
for convenience and without intending to voluntarily limit the
scope of this application to any single invention or inventive
concept, if more than one is, in fact, disclosed. Thus, although
specific embodiments have been illustrated and described herein,
any arrangement calculated to achieve the same purpose may be
substituted for the specific embodiments shown. This disclosure is
intended to cover any and all adaptations or variations of various
embodiments. Combinations of the above embodiments, and other
embodiments not specifically described herein, will be apparent to
those of skill in the art upon reviewing the above description.
* * * * *