Note: Descriptions are shown in the official language in which they were submitted.
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1
HIGH TORQUE GUIDEWIRE DEVICE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001]
This application claims priority to United States Patent Application No.
17/382,271 filed July 21, 2021 entitled "High Torque Guidewire Device" which
is a
continuation-in-part of United States Patent Application No. 17/154,777, filed
January 21,
2021 entitled -Guidewire having Enlarged, Micro-Fabricated Distal Section".
This
application also claims priority to and the benefit of United States
Provisional Patent
Application Serial 63/180,061, filed April 26, 2021 entitled "High Torque
Guidewire
Device-. The entire contents of each of the above applications is incorporated
by reference
in their entireties
BACKGROUND
[0002]
Guidewire devices are often used to lead or guide catheters or other
interventional devices to a targeted anatomical location within a patient's
body. Typically,
guidewires are passed into and through a patient's vasculature in order to
reach the target
location, which may be at or near the patient's heart or brain, for example.
Radiographic
imaging is typically utilized to assist in navigating a guidewire to the
targeted location. In
many instances, a guidewire is placed within the body during the
interventional procedure
where it can be used to guide multiple catheters or other interventional
devices to the
targeted anatomical location.
[0003] Guidewires
are available with various outer diameter sizes. Widely utilized
sizes include 0.010, 0.014, 0.016, 0.018, 0.024, 0.035, and 0.038 inches, for
example,
though they may also be smaller or larger in diameter. Because torque
transmission is a
function of diameter, larger diameter guidewires typically have greater torque
transmission
(the ability to effectively transfer torque from proximal portions of the wire
to more distal
portions of the wire or "torqueability-). On the other hand, smaller diameter
guidewires
typically have greater flexibility.
[0004]
Guidewires with good torquability are beneficial in that they provide
effective
navigation and good alignment between rotation at the proximal end and
corresponding
movement at thc distal end, which can be important when navigating tortuous
anatomy.
Simply increasing the size of the guidewire can increase its torquability, but
may overly
increase the stiffness of the guidewire as well. An overly stiff guidewire can
lead to
difficulties in initial placement of the guidewire at the targeted treatment
site. Moreover,
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there are known methods for increasing guidewire flexibility, such as reducing
the core
wire diameter, but these often come at the expense of torquability of the
device.
[0005] What is needed, therefore, is a guidewire device with
dimensions suitable for
various intravascular procedures (including, for example, neurovascular and
cardiovascular procedures) capable of providing enhanced torquability without
being
excessively stiff In other words, there is an ongoing need for guidewire
devices capable
of providing high levels of torsional stiffness without
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Various objects, features, characteristics, and
advantages of the invention will
113 become apparent and more readily appreciated from the following
description of the
embodiments, taken in conjunction with the accompanying drawings and the
appended
claims, all of which form a part of this specification. In the Drawings, like
reference
numerals may be utilized to designate corresponding or similar parts in the
various Figures,
and the various elements depicted are not necessarily drawn to scale, wherein:
[0007] Figure 1 illustrates an embodiment of a guidewire device having a
core and an
outer tube and which may utilize one or more of the components described
herein;
[0008] Figure 2 illustrates an exemplary embodiment of a
guidewire device with a tube
that has an outer diameter that is larger than an outer diameter of a proximal
section of the
core;
[0009] Figure 3 is a detailed view of the distal section of the guidewire
of Figure 2,
with the tube structure removed to better illustrate underlying features of
the device;
100101 Figure 4 is a detailed view of the tube of the
guidewire of Figure 2;
[0011] Figure 5 is a cross-sectional view of a distal section
of the guidewire of Figure
2, showing alignment of the beams of a one-beam section of the tube with a
flattened distal
section of the core;
[0012] Figures 6 and 7 are cross-sectional views of the
guidewire of Figure 2 showing
that the outer diameter of the tube is greater than the outer diameter of the
proximal section
of the core;
[0013] Figures 8 and 9 illustrate torsional stiffness vs.
sample twist for guidewire
devices, comparing a guidewire device according to the present disclosure
(labelled -A24
Soft") to other prior art guidewire devices, showing that the guidewire device
according
to the present disclosure beneficially provides higher torsional stiffness;
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[0014]
Figure 10 illustrates bending stiffness profiles of various guidewire
embodiments according to the present disclosure (labelled as -A24 Soft", "A24
Standard",
and "A24 Support") in terms of equivalent stainless-steel (304V) wire
diameter; and
[0015]
Figures 11-13 compare these respective bending stiffness profiles to other
prior
art guidewire devices, illustrating that bending stiffness is not adversely
affected despite
the enhanced torque provided by the presently disclosed guidewire devices.
DETAILED DESCRIPTION
Introduction
[0016]
Figure 1 schematically illustrates the general components of a guidewire
100
to that
may utilize one or more features described in greater detail below. The
illustrated
guidewire 100 includes a core 102 and an outer tube 104. The core 102 includes
a distal
section 103 (also referred to herein as the distal core 103) that extends into
the outer tube
104 as shown. The distal core 103 may be tapered, either continuously or in
one or more
discrete sections, so that more distal sections have a smaller diameter and
greater flexibility
than more proximal sections. In some embodiments, the most distal section of
the core 102
may be flattened into a ribbon-like shape with a flat, rectangular, or oblong
cross section.
For example, the distal core 103 may be ground so as to progressively taper to
a smaller
diameter at the distal end.
[0017]
The core 102 and the tube 104 are typically formed from different
materials.
For example, the tube 104 is preferably formed from a relatively flexible and
elastic
material such as nitinol, whereas the core 102 may be formed from a relatively
less flexible
and elastic material such as stainless steel. Forming the core 102 from
stainless steel (or
other materials with similar modulus of elasticity) may be advantageous
because it allows
the distal tip to hold a shape when selectively bent/shaped by an operator and
because
stainless steel provides sufficient modulus of elasticity to provide more
responsive
translational movement. While these materials are presently preferred, other
suitable
materials such as polymers or other metals/alloys may additionally or
alternatively be
utilized.
[0018]
The tube 104 is coupled to the core 102 (e.g., using adhesive, soldering,
and/or
welding) in a manner that beneficially allows torsional forces to be
transmitted from the
core 102 to the tube 104 and thereby to be further transmitted distally by the
tube 104. A
medical grade adhesive or other suitable material may be used to couple the
tube 104 to
the core wire 102 at the distal end 110 of the device to form an atraumatic
covering.
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[0019]
The outer tube 104 may include a cut pattern that forms fenestrations 106
in
the tube. The pattern of fenestrations 106 may be arranged to provide desired
flexibility
characteristics to the tube 104, including the promotion of preferred bending
directions,
the reduction or elimination of preferred bending directions, or gradient
increases in
flexibility along the longitudinal axis, for example. Examples of cut patterns
and other
guidewire device features that may be utilized in the guidewire devices
described herein
are provided in detail in United States Patent Application Publication Nos.
2018/0193607,
2018/0071496, and 2020/0121308, the entireties of each of which are
incorporated herein
by this reference.
lo [0020] The
proximal section of the guidewire device 100 (the portion extending
proximally from the tube 104) extends proximally to a length necessary to
provide
sufficient guidewire length for delivery to a targeted anatomical area. The
guidewire
device 100 typically has a length ranging from about 50 cm to about 350 cm,
more
commonly about 200 cm, depending on particular application needs. The tube 104
may
have a length ranging from about 5 cm to about 350 cm, more typically about 15
cm to
about 50 cm, such as about 25 cm to about 40 cm.
[0021]
The guidewire device 100 may have a diameter of about 0.010 inches to
about
0.038 inches, though larger or smaller sizes may also be utilized depending on
particular
application needs. For example, particular embodiments may have outer diameter
sizes
corresponding to standard guidewire sizes such as 0.014 inches, 0.016 inches,
0.018
inches, 0.024 inches, or other such sizes common to guidewire devices. The
distal section
103 of the core 102 may taper to a diameter of about 0.002 inches, or a
diameter within a
range of about 0.001 to 0.005 inches. In some embodiments, the distal tip may
be flattened
(e.g., to a rectangular cross section) to further enhance bending flexibility
while
minimizing reductions in cross-sectional area needed for tensile strength. In
such
embodiments, the cross section may have dimensions of about 0.001 inches by
0.003
inches, for example. In some embodiments, the tube 104 has a length within a
range of
about 3 to 350 cm.
[0022]
Additional features and details regarding the foregoing components are
described in further detail below. The following examples may be particularly
beneficial
in applications where the corresponding catheter is about sized at 0.027
inches or greater,
and the guidewire is thus beneficially sized at about 0.024 inches or greater
in order to
limit the amount of annular space between the inner surface of the catheter
and the outer
surface of the guidewire, but still allow for relative movement between them.
In such
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implementations, the guidewires described herein are able to provide
sufficient diameter
in the distal sections of the device to limit the annular space, while still
maintaining
effective torqueability and lateral flexibility. These sizes are not limiting,
however, and
the same features and details described below may also be utilized in
guidewires that are
5 smaller or larger than 0.024 inches.
Distal Section Features
[0023]
Figure 2 illustrates an example of a guidewire 200. Except where noted
herein,
the guidewire 200 may include any of the general features described above in
relation to
guidewire 100, with like reference numbers indicating like parts. As shown,
the guidewire
in 200 includes a core 202 and an outer tube 204, with a distal section 203
of the core 202
inserted into the tube 204. The outer tube 204 includes a plurality of
fenestrations 206. A
polymer-based adhesive may form an atraumatic distal tip 210.
[0024]
The core 202 also includes a proximal section 201 (also referred to herein
as
the proximal core 201) that is disposed proximal of the outer tube 204 and is
not inserted
into the outer tube 204. The proximal core 201 may comprise a friction-
lowering coating,
such as polytetrafluoroethylene (PTFE) and/or other suitable coating
materials. The tube
204 may also include a coating, preferably a suitable hydrophilic coating
and/or other
suitable coating materials.
[0025]
Preferably, the outer diameter of the tube 204 is slightly larger than the
outer
diameter of the proximal core 201. In one exemplary embodiment, the proximal
core 201
has an outer diameter of about 0.018 inches, while the tube 204 has an outer
diameter of
about 0.024 inches. Other core and/or tube sizes may also be utilized,
however. Preferably,
the tube 204 has an outer diameter that is about 10% or more larger than the
outer diameter
of the proximal core 201, more preferably about 15% to about 80% larger, or
more
preferably about 20% to about 70% larger, such as about 25% to about 35%
larger.
[0026]
This is further illustrated by the cross-sectional views of Figures 6 and
7. As
shown, the outer diameter (D1) of the proximal core 201 is less than the outer
diameter
(D2) of the tube 204. The ratio of D2 to D1 may be, for example, about 1.1 to
about 3,
more preferably about 1.15 to about 2, or about 1.2 to about 1.75.
[0027] As mentioned
above, a larger outer diameter in the tube 204 can better match
certain desired catheter sizes at the catheter distal tip portion and thereby
reduce the
amount of annular space between the guidewire and catheter during placement of
the
catheter over the guidewire. This is particularly beneficial at the more
distal sections of
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the guidewire, which are more likely to be navigated through deeper, more
tortuous
portions of the patient's vasculature.
[0028]
However, increasing the diameter of the core 202 to match the larger
diameter
of the tube 204 may make the core 202 too stiff for use in certain desired
applications.
Thus, maintaining a smaller core 202, while increasing the size of the tube
204 relative to
the core 202, allows use of the more flexible core 202 while still enabling
the benefits of
a larger tube 204 at the distal sections of the guidewire 200.
[0029]
As explained in more detail below, however, providing a tube 204 that has
a
larger outer diameter than the core 202 can introduce other challenges. In
particular, the
difference in diameter between the outer tube 204 and the distal core 203
enlarges the
annular space between the outer surface of the distal core 203 and the inner
surface of the
tube 204. Because the tube 204 can be more flexible than the distal core 203,
as the wire
navigates a bend, the distal core 203 may be positioned off-center from the
center line of
the tube 204. As the guidewire is moved through the vasculature, this off-
centering can
disrupt the smooth distal transmission of rotational movement, causing a
buildup and
sudden release of forces which lead the guidewire to move with a "snap" and/or
"whip" to
a non-desired preferential rotational location. This disruption to the tactile
feel and
rotational control of the guidewire can make it more difficult for the
operator to
rotationally position the guidewire as intended, raising the risk of
interventional procedure
delays, suboptimal outcomes, inability to access the target location, or even
tissue injury.
[0030]
The embodiments described herein beneficially provide additional features
that
assist in radially centering the distal core 203 within the tube 204 even
though the tube
204 has a larger outer diameter than the proximal core 201. One or more
centering
mechanisms may be included to beneficially reduce undesirable whip and/or snap
movements of the guidewire (i.e., the centering mechanisms may improve
rotational
control), thereby enabling a user to have greater rotational control and
improved tactile
handling of the guidewire.
[0031]
Figure 3 illustrates an expanded view of the distal section of the
guidewire 200
with the tube 204 removed in order to better visualize the distal core 203 and
some of the
other underlying components. As shown, the core 202 includes one or more
transition
zones 208 where the core 202 tapers to a smaller diameter. A distal end
section 211 of the
core 202 may be flattened. The one or more transition zones 208 may be
discrete, with one
or more sections of the core of substantially continuous outer diameter
disposed between,
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or the distal core 203 may have a substantially continuous taper along all or
most of its
length.
[0032]
A bushing 212 may be included at the point forming the joint to which the
proximal end of the tube 204 is attached. The bushing 212 may have an outer
diameter that
substantially matches the outer diameter of the proximal core 201. The bushing
212 may
be formed from the same material as the tube 204 (e.g., nitinol). The bushing
212 provides
for better centering between the core 202 and the tube 204 and/or reduces the
amount of
adhesive needed to bond the separate components. Although shown here as a
tube, the
bushing 212 may have alternative geometries such as a coil, braid, slotted/cut
tube,
etcetera.
[0033]
As shown, the bushing 212 may also include a chamfered or beveled surface
214 on its proximal end to provide a smooth transition between different
diameters. The
distal end of the bushing 212 may also be chamfered or beveled. Even though
the distal
end of the bushing 212 will be covered by the tube 204, providing a bushing
212 with a
chamfer/bevel on both ends can aid in manufacturing, eliminating the need to
ensure
proper orientation of the bushing and eliminating the potential for erroneous
orientation.
[0034]
The illustrated guidewire 200 includes a proximal coil 216, a distal coil
218,
and a bushing coil 220 positioned over the proximal coil 216 and the distal
coil 218. The
distal coil 218 is preferably formed of a radiopaque material, such as
platinum group, gold,
silver, palladium, iridium, osmium, tantalum, tungsten, bismuth, dysprosium,
gadolinium,
and the like. The distal coil 218 thus preferably allows radiographic
visualization of the
distal end of the guidewire 200 during a procedure. The distal coil 218 may
have a length
of about 0.5 cm to about 20 cm, or more typically about 3 cm to about 15 cm,
such as
about 10 cm.
[0035] The proximal
coil 216 may be formed from a non-radiopaque material such as
stainless steel, other suitable metal, a suitable polymer, or other suitable
material. The
proximal coil 216 may be attached to the distal core 203 at a point adjacent
to or near to
the proximal end of the distal coil 218 and/or at any point along the
coincident length of
the distal core 203, most commonly at or near each end of the proximal coil
216. The
proximal coil 216 may have a length of about 1 to 25 cm, or more typically
about 3 to 20
cm, such as about 5 to 15 cm. Technically, the distal coil 218 could be
extended further
proximally to take the place of the proximal coil 216. However, materials that
function
well as radiopaque markers (e.g., platinum) are relatively expensive. Also,
their use as a
packing material to fill large portions of the annular space could cause the
distal section of
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the guidewire 200 to be overly bright when imaged under x-ray fluoroscopy and
thus not
allow the operator to visualize other areas of interest. Thus, the proximal
coil 216 is
preferably separate from, and formed from a different material than, the
distal coil 218.
[0036]
The proximal coil 216 and the distal coil 218 aid in filling some of the
annular
space between the distal core 203 and the tube 204. Although the coil examples
illustrated
herein are shown having wires with a circular cross section, it will be
understood that other
coil types may also be utilized. For example, centering coil(s) may be edge-
wound and/or
may have a ribbon, rectangular, oblong, or other non-circular shaped cross-
sectional shape.
[0037]
Although the proximal coil 216 and distal coil 218 aid in filling some of
the
annular space, additional annular space remains, particularly when a somewhat
larger tube
204 is utilized. The wire size of the proximal coil 216 and distal coil 218
could be increased
to fill more space. However, increasing wire size too much may introduce
excessive
stiffness to the device. Preferably, the wire size of the proximal coil 216
and distal coil
218 is about 0.008 inches or less, or about 0.006 inches or less, or more
preferably about
0.004 inches or less, such as about 0.002 inches or less.
[0038]
To aid in filling the remainder of the annular space, the guidewire 200
may
include a bushing coil 220. The bushing coil 220 may be disposed over the
proximal coil
216 and the distal coil 218. The bushing coil 220 may extend over the entirety
of both of
the proximal coil 216 and the distal coil 218. As with the proximal coil 216
and the distal
coil 218, the wire diameter of the bushing coil 220 is preferably limited. For
example, the
wire diameter of the bushing coil, when a metal material is utilized, may be
about 0.008
inches or less, or about 0.006 inches or less, or more preferably about 0.004
inches or less,
such as about 0.002 inches or less. The bushing coil 220 may be formed of
stainless steel
and/or other suitable material, such as another metal or a polymer. In
examples where a
polymer material is utilized, the modulus may be much less relative to a metal
material
and the wire diameter of the coil may therefore be larger without overly
affecting the
bending stiffness. In at least some embodiments, wire diameter of one or more
of the coils
(e.g., the bushing coil 220) may be up to about 0.025 inches, or up to about
0.020 inches,
or up to about 0.015 inches.
100391 The use of a
bushing coil 220 in addition to the proximal coil 216 and distal
coil 218 aids in filling the annular space between the distal core 203 and the
tube 204
without the use of over-sized coils. This aids in maintaining centering of the
distal core
203 within the tube 204, which prevents the undesirable effects of
misalignment that have
been described above while also minimally impacting the bending flexibility of
the device.
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[0040]
In some embodiments, the bushing coil 220 may be substantially coincident
with the proximal coil 216 and the distal coil 218. Alternatively, as shown,
the bushing
coil 220 may extend farther proximally than the proximal coil 216. This allows
the bushing
coil 220 to fill in more of the annular space even at portions where the
proximal coil 216
is not able. That is, because of the tapered profile of the distal core 203,
certain more
proximal portions of the annular space do not fit both the proximal coil 216
and the bushing
coil 220, but may still be filled by the further extending proximal portion of
the bushing
coil 220. The bushing coil 220 preferably extends along a substantial portion
of the length
of the tube 204. For example, the bushing coil 220 may have a length of at
least about 60%
of the length of the tube 204, or at least about 75% of the length of the tube
204, or at least
about 80% of the length of the tube 204, or at least about 85% of the length
of the tube
204.
[0041]
In preferred embodiments, the proximal coil 216 and the distal coil 218
are
each wound in a first direction, while the bushing coil 220 is counter-wound
in a second,
opposite direction. This beneficially limits interlocking and binding of the
bushing coil
220 to either of the proximal coil 216 or the distal coil 218. The bushing
coil 220 may also
have a pitch that is different (e.g., narrower) than that of the proximal coil
216 or the distal
coil 218. For example, the proximal coil 216 and/or the distal coil 218 may
have a pitch of
about 0.002 inches to about 0.008 inches, or about 0.003 inches to about 0.007
inches,
whereas the bushing coil 220 may have a pitch of about 0.001 inches to about
0.006 inches,
or about 0.002 inches to about 0.005 inches.
[0042]
The proximal coil 216, the distal coil 218, and the bushing coil 220 are
preferably configured to fill a substantial portion of the volume of the
annular space
between the distal core 203 and the tube 204. For example, proximal coil 216,
the distal
coil 218, and the bushing coil 220 may be configured to fill approximately 20%
or more,
35% or more, 50% or more, 60% or more, 70% or more, 80% or more, or even up to
about
90% or more of the volume of the annular space. Of course, other conventional
guidewires
may include joints or bushings that fill up large portions of the annular
space at the
particular part of the guidewire they are located. However, when the entire
length of the
outer tube is considered, such joints and bushings fill relatively little of
the volume of the
overall annular space.
[0043]
The centering mechanism principles described herein may be utilized with
other structural configurations to provide beneficial centering effects. For
example, while
the above embodiments describe various centering mechanisms with a core as the
"inner
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member" and a microfabricated tube as the -outer member," other structures may
additionally or alternatively be utilized as the outer and/or inner members
along with one
or more of the described centering mechanisms.
[0044]
For example, the inner member may be a wire (such as a ground core as
5
described above), a tube (e.g., metal or polymer hypotube or metal or polymer
microfabricated tube), a braid, or a coil. By way of further example, the
outer member may
be a tube (e.g., metal or polymer hypotube or metal or polymer microfabricated
tube), a
braid, a coil, or a polymer tube impregnated with a braid or coil. The
centering mechanism
may include a set of coils such as those described above, or may additionally
or
10
alternatively include other structures for providing centering of the inner
member within
the outer member. For example, one or more of the coils 216, 218, 220 may be
replaced
by one or more tubes (e.g., metal or polymer hypotube or metal or polymer
microfabricated
tube), braided sections, or sets of stacked rings.
[0045]
Figure 4 illustrates the tube 204 separate from the core 202 and some of
the
other components of the device. The tube 204 extends between a proximal end
222 and a
distal end 224. The fenestrations 206 Conned within the tube 204 may be made
according
to a variety of cut patterns. Preferably, the overall effect of the
fenestrations provides a
flexibility gradient across the tube 204 where more flexibility increases
closer to the distal
end 224. Typically, greater flexibility can be provided by removing more of
the stock
material, such as by increasing the depth of the cut, decreasing the space
between adjacent
cuts, and/or reducing the number of axially extending beams 226 connecting
each of the
circumferentially extending rings 228.
[0046]
The illustrated embodiment, for example, may include a three-beam section
230 (three beams connecting each adjacent pair of rings) that transitions to a
two-beam
section 232 (two beams connecting each adjacent pair of rings) that
transitions to a one-
beam section 234 (a single beam connecting each adjacent pair of rings).
Within each of
these sections, the cut depth and/or cut spacing may also be adjusted to
provide a smooth
intra-section and inter-section flexibility gradient. For example, the two-
beam section 232
may have progressively less distance between cuts as it advances toward the
distal end
224. It may then transition to the one-beam section 234, which itself then
includes
progressively less distance between cuts as it advances toward the distal end
224.
[0047]
The one-beam section 234 may have a length of about 0.5 cm to about 3 cm,
or about 0.75 cm to about 2 cm, for example. The two-beam section 232 may have
a length
of about 4 cm to about 16 cm, or about 6 cm to about 12 cm, for example. The
three-beam
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section 230 may have a length of about 12 cm to about 36 cm, or about 18 cm to
about 30
cm, for example. In other words, the three-beam section 230 may be about 2 to
5 times
longer than the two-beam section 232, and the two-beam section 232 may be
about 2 to 5
times longer than the one-beam section 234. Designing the tube 204 with these
proportions
of cut/beam sections has been found to provide effective balance of axial,
lateral, and
torsional stiffness for most applications.
[0048]
The tube 204 may also include a distal-most section 235 that has a two-
beam
pattern. This section is preferably relatively short, such as about 0.5 cm or
less, or about
0.25 cm or less, or about 0.15 cm or less. Providing a relatively short two-
beam section at
section 235 provides added surface area for an adhesive material applied at or
near the
distal end 224 of the tube 204 to bond, allowing a stronger coupling between
the distal end
224 and any internal components bonded thereto.
[0049]
Certain sections of the tube 204 may have cuts that are rotationally
offset so as
to avoid the formation of any preferred bending planes. For example, an
angular offset
may be applied after each cut or series of cuts such that the overall
resulting pattern of
beams 226 in the tube 204 do not align in a way that forms preferred bending
planes.
[0050]
Other sections of the tube 204 may include a preferred bending plane. For
example, the one-beam section 234 may be aligned as shown in Figure 4, with
each beam
offset by about 1800 from the previous beam. These beams may also be aligned
with the
bending plane of the flattened distal end section 211 of the core. Figure 5
illustrates, in
cross-section, how the beams 226 of the one-beam section 234 are preferably
aligned in
the same plane as the flattened, wider section of the distal end section 211
of the core.
Effective Torque & Torque to Rend Ratios
[0051]
Figures 8 and 9 illustrate that guidewire devices of the present
disclosure are
capable of providing higher torque (i.e., torsional stiffness) as compared to
various prior
art devices. In Figures 8 and 9 and elsewhere herein, the device labelled "A24
Soft"
represents an example of a guidewire device as described herein, while other
labels refer
to other prior art devices. In particular, "A14 Soft- refers to the Aristotle
14 Guidewire
with soft profile (0.014 inch outer diameter, sold by Scientia Vascular), the
"A18 Soft"
refers to the Aristotle 18 Guidewire with soft profile (0.018 inch outer
diameter, sold by
sold by Scientia Vascular), the "Synchro2 Soft" refers to the Synchro2 with
soft profile
(0.014 inch outer diameter, sold by Stryker Neurovascular), the Chikai 14
refers to the
Asahi Chikai guidewire (0.014 inch outer diameter, sold by Asahi Intecc
Medical), and the
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-A14 Soft CoreWire" and -A18 Soft CoreWire" are the same as the -A14 Soft" and
the
"A18 Soft" but only the core wire without outer tube or other components. In
other figures,
the label "Fathom 16- refers to the Fathom 0.016 inch outer diameter guidewire
sold by
Boston Scientific. The label "A14" is synonymous with "AR14", "A18" is
synonymous
with -AR18", and the like.
[0052]
As shown, the "A24 Soft" is more effective in providing torsional
stiffness than
the comparative prior art devices. Table 1 summarizes the data of Figures 8
and 9 by
showing the rotational stiffness (averaged over all measurement points across
the 35 cm
distal section) of the "A24 Soft" and some of the other prior art guidewire
devices.
Table 1: Torque / Rotational Stiffness
Guidewire Avg. Rotational Stiffness Avg. Rotational
Stiffness
Device (inch=pounds / degree) (rsIgn / rad)
A24 Soft 2.59 E-06 1.68 E-05
Al4 Soft 1.56E-06 1.01 E-05
A18 Standard 1.99 E-06 1.29 E-05
A18 Soft 3.45E-07 2.24E-06
Chikai 14 7.95 E-07 5.15 E-06
Synchro2 Soft 1.04 E-06 6.73 E-06
[0053]
Advantageously, the high torque provided by the disclosed guidewire device
does not come at the expense of significantly reduced bending flexibility.
Figure 10
illustrates profiles of bending stiffness (i.e., flexural rigidity) of various
guidewire
embodiments according to the present disclosure (labelled as "A24 Soft", "A24
Standard",
and "A24 Support-) in terms of equivalent stainless-steel (304V) wire
diameter. Because
bending stiffness of a beam is a constant directly related to the cross-
sectional dimensions
of the beam, the measured guidewire stiffness can be related to the constant
in terms of a
stainless-steel wire that would provide the same bending stiffness
measurement.
[0054] To carry out
the measurement procedure, the distal tip of the guidewire to be
measured was clamped in a collet pin vise with the guidewire tip protruding
out of the
vise. The guidewire tip was mounted so that the flattened tip of the core
(where applicable)
was aligned in the horizontal orientation and the measurement was taken in the
direction
intended to be shaped. Additional measurement points were tested by advancing
the wire
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in the collet and trimming the wire as necessary so that the guidewire extends
past a load
cell roller midpoint.
[0055]
Figures 11-13 compare these respective bending stiffness profiles to other
prior
art guidewire devices, illustrating that bending stiffness is not adversely
affected despite
the enhanced torque provided by the A24 guidewire devices. This is true even
though some
of the comparison devices have a smaller size and would therefore be expected
to have
greater flexibility in bending (i.e., less bending stiffness).
[0056]
The data provided herein illustrate that guidewire devices made according
to
the present disclosure are capable of providing relatively high torque without
significantly
and detrimentally increasing the bending stiffness. Accordingly, a -torque to
bend" ratio
can be utilized as a useful metric that highlights the beneficial properties
of the presently
disclosed guidewire devices. The -torque to bend" ratio is a value indicating
the
relationship between torsional stiffness (as the numerator) and bending
stiffness (as the
denominator). The exact value may change depending on the units utilized in
each of the
input measures, but so long as units are selected consistently, comparisons
across different
devices can be made. In Table 2, the torque to bend ratio is shown in units of
radians',
which results from a rotational stiffness numerator in units of (N. m2/rad)
divided by a
bending stiffness denominator in units of N. m2.
Table 2: Bending Stiffness & "Torque to Bend" Ratios
Guidewire Distance Bending Bending 'Torque to
Bend'
Device from Distal Stiffness Stiffness Ratio
End (equiv. SS (N=m2) (rad')
(cm) diam.)
A24 Soft 0.5 1.74 3.5E-08 479.36
1 2.18 8.85E-08 189.63
1.5 2.44 1.35E-07 124.33
2 2.81 2.38E-07 70.62
3 3.45 5.8E-07 28.91
4 3.45 5.52E-07 30.39
5 3.57 6.48E-07 25.88
6 3.65 6.84E-07 24.53
7 4.11 1.11E-06 15.08
8 4.47 1.53E-06 10.95
9 4.92 2.31E-06 7.27
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5.38 3.27E-06 5.13
12.5 5.42 3.34E-06 5.02
5.72 4.27E-06 3.93
17.5 5.89 4.81E-06 3.49
6.00 5.17E-06 3.25
22.5 6.86 8.78E-06 1.91
7.47 1.22E-05 1.38
27.5 8.59 2.11E-05 0.79
9.99 3.86E-05 0.43
32.5 11.73 7.34E-05 0.23
14.10 0.000152 0.11
A14 Soft 0.5 2.36 1.23E-07 81.82
1 2.42 1.37E-07 73.50
2 2.71 2.16E-07 46.68
3 3.15 3.95E-07 25.58
4 3.53 6.18E-07 16.34
5 3.85 8.74E-07 11.55
6 4.18 1.22E-06 8.25
8 4.85 2.2E-06 4.58
9 4.86 2.22E-06 4.54
10 5.03 2.56E-06 3.94
11 5.11 2.73E-06 3.71
12 5.12 2.76E-06 3.67
13 5.07 2.63E-06 3.83
14 5.10 2.71E-06 3.72
15 5.08 2.67E-06 3.79
16 5.25 3.04E-06 3.32
17 5.17 2.85E-06 3.54
18 5.09 2.69E-06 3.75
19 5.02 2.53E-06 3.99
20 4.87 2.26E-06 4.47
21 5.07 2.65E-06 3.82
22 5.01 2.52E-06 4.01
23 5.08 2.66E-06 3.80
25 5.08 2.66E-06 3.80
27 5.27 3.09E-06 3.26
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31 6.01 5.23E-06 1.93
33 7.91 1.56E-05 0.65
A18 Standard 0.5 2.15 8.25E-08 156.20
1 2.28 1.06E-07 121.82
2 3.48 5.67E-07 22.71
3 3.68 7.14E-07 18.04
4 3.86 8.65E-07 14.89
5 4.15 1.15E-06 11.21
6 4.22 1.23E-06 10.46
7 4.44 1.51E-06 8.54
8 4.66 1.83E-06 7.03
9 4.77 2.01E-06 6.41
10 5.05 2.53E-06 5.10
12.5 5.65 3.96E-06 3.25
15 5.96 4.89E-06 2.63
17.5 6.01 5.07E-06 2.54
6.06 5.24E-06 2.46
22.5 6.15 5.54E-06 2.33
6.75 8.08E-06 1.60
27.5 7.84 1.47E-05 0.88
9.30 2.90E-05 0.44
32.5 10.88 5.43E-05 0.24
12.19 8.58E-05 0.15
A18 Soft 0.5 1.90 5.03E-08 44.42
1 1.88 4.88E-08 45.82
2 3.16 3.86E-07 5.79
3 3.61 6.56E-07 3.41
4 3.69 7.16E-07 3.12
5 3.90 8.99E-07 2.49
6 3.83 8.33E-07 2.68
7 3.98 9.72E-07 2.30
8 4.18 1.19E-06 1.89
9 4.31 1.34E-06 1.67
10 4.57 1.70E-06 1.32
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12.5 5.10 2.63E-06 0.85
15 5.31 3.08E-06 0.73
17.5 5.28 3.02E-06 0.74
20 5.29 3.05E-06 0.73
22.5 5.30 3.05E-06 0.73
25 6.09 5.33E-06 0.42
27.5 7.31 1.11E-05 0.20
30 9.13 2.70E-05 0.08
32.5 10.62 4.94E-05 0.05
35 12.36 9.05E-05 0.02
Synchro2 Soft 0.5 2.15 8.55E-08 78.73
2.5 2.72 2.19E-07 30.73
3.31 4.8E-07 14.01
7.5 4.14 1.18E-06 5.73
4.50 1.64E-06 4.10
12.5 4.57 1.74E-06 3.86
4.56 1.73E-06 3.89
17.5 4.72 1.99E-06 3.39
4.88 2.27E-06 2.97
22.5 5.24 3.02E-06 2.23
5.45 3.53E-06 1.91
27.5 6.06 5.39E-06 1.25
6.36 6.54E-06 1.03
32.5 6.91 9.12E-06 0.74
6.66 7.87E-06 0.86
37.5 7.43 1.22E-05 0.55
8.76 2.36E-05 0.29
42.5 10.14 4.23E-05 0.16
11.37 6.69E-05 0.10
100571
The data provided in Figures 8-13 and in Tables 1 and 2 can be utilized to
calculate such torque to bend ratios for the presently disclosed guidewires
and for the
selection of comparative devices. The guidewire devices disclosed herein
beneficially
5 provide greater torque to bend ratios than prior art devices. In some
implementations, this
type of comparison can be made across devices of similar size. That is, for a
given
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guidewire size, the presently disclosed guidewire devices provide improved
torque to bend
ratios, even though a differently sized guidewire may have a higher torque to
bend ratio
because of size differences. For example, some embodiments may have an outer
diameter
size of no more than about 0.024 inches.
[0058] As further
illustrated by the data of Figures 8-13 and Tables 1 and 2, a
guidewire device according to the present disclosure can provide a torque to
bend ratio of
greater than 160 rad-1, or about 200 rad-1 or greater, or about 250 rad-1 or
greater, or about
300 rad" or greater, or about 350 rad" or greater, or about 400 rad" or
greater, or about
450 rad-1 or greater, at a distal 0.5 cm section of the guidewire device
(e.g., at about 0.5
in cm from
the distal end). The other tested guidewire devices were unable to provide a
torque
to bend ratio at these values.
[0059]
In some embodiments, a guidewire device according to the present
disclosure
can provide a torque to bend ratio of 80 rad-1 or greater, or about 100 rad'
or greater, or
about 120 rad-1 or greater, at a distal 1.5 cm section of the guidewire device
(e.g., at about
1.5 cm from the distal end). The other tested guidewire devices were unable to
provide a
torque to bend ratio at these values.
[0060]
In some embodiments, a guidewire device according to the present
disclosure
can provide a torque to bend ratio of 130 rad-1 or greater, or about 150 rad-1
or greater, or
about 170 rad-1 or greater, at a distal 1.0 cm section of the guidewire device
(e.g., at about
1.0 cm from the distal end). The other tested guidewire devices were unable to
provide a
torque to bend ratio at these values.
[0061]
In some embodiments, a guidewire device according to the present
disclosure
can provide a torque to bend ratio of 50 rad' or greater, or about 60 rad-1 or
greater, or
about 65 rad-1 or greater, at a distal 2.0 cm section of the guidewire device
(e.g., at about
2.0 cm from the distal end). The other tested guidewire devices were unable to
provide a
torque to bend ratio at these values.
[0062]
In some embodiments, a guidewire device according to the present
disclosure
can provide a torque to bend ratio of 15 rad-1 or greater, or about 20 rad-1
or greater, or
about 25 rad-1 or greater, at a distal 5.0 cm section of the guidewire device
(e.g., at about
5.0 cm from the distal end). The other tested guidewire devices were unable to
provide a
torque to bend ratio at these values.
[0063]
In some embodiments, a guidewire device according to the present
disclosure
can provide a torque to bend ratio of 8 rad-1 or greater, or about 9.5 rad-1
or greater, or
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about 11 rad-1 or greater, at a distal 8.0 cm section of the guidewire device
(e.g., at about
8.0 cm from the distal end). The other tested guidewire devices were unable to
provide a
torque to bend ratio at these values.
[0064]
Other torque to bend ratios for the tested devices can be readily
determined
using the data provided by Figures 8-13 and summarized by Tables 1 and 2.
Abbreviated List of Defined Terms
[0065]
While certain embodiments of the present disclosure have been described in
detail, with reference to specific configurations, parameters, components,
elements,
etcetera, the descriptions are illustrative and are not to be construed as
limiting the scope
in of the claimed invention.
[0066]
Furthermore, it should be understood that for any given element of
component
of a described embodiment, any of the possible alternatives listed for that
element or
component may generally be used individually or in combination with one
another, unless
implicitly or explicitly stated otherwise.
[0067] In addition,
unless otherwise indicated, numbers expressing quantities,
constituents, distances, or other measurements used in the specification and
claims are to
be understood as optionally being modified by the term "about- or its
synonyms. When
the terms "about," -approximately," -substantially," or the like are used in
conjunction
with a stated amount, value, or condition, it may be taken to mean an amount,
value or
condition that deviates by less than 20%, less than 10%, less than 5%, less
than 1%, less
than 0.1%, or less than 0.01% of the stated amount, value, or condition. At
the very least,
and not as an attempt to limit the application of the doctrine of equivalents
to the scope of
the claims, each numerical parameter should be construed in light of the
number of
reported significant digits and by applying ordinary rounding techniques.
[0068] Any headings
and subheadings used herein are for organizational purposes only
and are not meant to be used to limit the scope of the description or the
claims.
[0069]
It will also be noted that, as used in this specification and the appended
claims,
the singular forms -a," -an" and -the" do not exclude plural referents unless
the context
clearly dictates otherwise. Thus, for example, an embodiment referencing a
singular
referent (e.g., "widget") may also include two or more such referents.
[0070]
It will also be appreciated that embodiments described herein may include
properties, features (e.g., ingredients, components, members, elements, parts,
and/or
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portions) described in other embodiments described herein. Accordingly, the
various
features of a given embodiment can be combined with and/or incorporated into
other
embodiments of the present disclosure. Thus, disclosure of certain features
relative to a
specific embodiment of the present disclosure should not be construed as
limiting
application or inclusion of said features to the specific embodiment. Rather,
it will be
appreciated that other embodiments can also include such features.
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