Note: Descriptions are shown in the official language in which they were submitted.
CA 02901190 2017-01-03
Anchoring Guidewire and Methods for Use
Background of the Invention
Guidewires may be utilized to direct medical devices into a desired target
vessel for
intervention. Conventional guidewire methods and devices may include a
steerable
guidewire that is not anchored in any way. When tortuous anatomies are
involved, the stiff
device may work to straighten the guide wire as the device is advanced over
the curved
portion of the guide wire and the steerable guidewire may often slip back out
of the target
vessel making it difficult to use the steerable guidewire as a coaxial rail to
guide a device into
the appropriate vessel.
Summary of the Invention
The present invention is directed to methods and apparatus that may include an
anchoring basket to anchor a guidewire to vasculature prior to graft
deployment. These
features may thereby improve the ease by which stent grafts can be placed in
branched
vessels and increase the speed and success of complex cases, while at the same
time lowering
the chance for complications. Anchoring the guidewire to the subject's
vasculature may have
a stabilizing effect for the tip of the catheter and afford greater stability
and confidence for
the operator. Once the anchoring basket is deployed it may be locked in place,
securing the
basket and may beneficially allow blood to continue to flow through the basket
and
downstream. Once anchored, the guidewire may be used as a common coaxial rail
for
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improved delivery of treatment devices such as bare metal stents, covered
stents, and other
over-the-wire devices.
Thus, in a first aspect, the present invention provides an anchoring guidewire
comprising: (a) an outer core, (b) an anchoring basket, (c) a steerable tip,
and (d) an actuator
core, where the outer core, the anchoring basket and the steerable tip are
axially aligned with
one another, and where the actuator core is movably disposed within both the
outer core and
the anchoring basket, and where the actuator core is coupled to the steerable
tip.
In one embodiment, the invention may provide that the anchoring basket
comprises a
plurality of strips defined in the outer core adjacent to the steerable tip,
where the plurality of
strips are substantially straight in a first neutral state and bow out in a
radial direction in a
second compressed state.
In another embodiment, the invention may provide that the anchoring basket
comprises a plurality of wires each with a proximal end and a distal end,
where each
proximal end of the plurality of wires is attached to a first holder and each
distal end of the
plurality of wires is attached to a second holder, where the plurality of
wires are substantially
straight in a first neutral state and bow out in a radial direction in a
second compressed state.
In a second aspect, the present invention also provides a method for deploying
an
anchoring guidewire, the method comprising: (a) introducing the anchoring
guidewire
according to the first aspect of the invention into an arterial configuration,
(b) placing the
actuator core under tension and causing the steerable tip to advance towards
the outer core,
and (c) moving the anchoring basket from a first neutral state to a second
compressed state.
Brief Description of the Drawings
Figure 1 A is a side view of the anchoring guidewire in a neutral state, in
accordance with one
embodiment of the invention.
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Figure 1B is a side view of the anchoring guidewire in a compressed state, in
accordance with
one embodiment of the invention.
Figure 2A is a side view of a locking mechanism in a neutral state, in
accordance with one
embodiment of the invention.
Figure 2B is a side view of a locking mechanism in a compressed state, in
accordance with
one embodiment of the invention.
Figure 2C is a side view of a locking mechanism in a locked state, in
accordance with one
embodiment of the invention.
Figure 3 is a flow chart depicting functions that can be carried out in
accordance with example
embodiment of the disclosed methods.
Detailed Description of the Invention
Exemplary methods and systems are described herein. It should be understood
that
the word "exemplary" is used herein to mean "serving as an example, instance,
or
illustration." Any embodiment or feature described herein as "exemplary" is
not necessarily
to be construed as preferred or advantageous over other embodiments or
features. The
exemplary embodiments described herein are not meant to be limiting. It will
be readily
understood that certain aspects of the disclosed systems and methods can be
arranged and
combined in a wide variety of different configurations, all of which are
contemplated herein.
Furthermore, the particular arrangements shown in the Figures should not be
viewed
as limiting. It should be understood that other embodiments may include more
or less of each
element shown in a given Figure. Further, some of the illustrated elements may
be combined
or omitted. Yet further, an exemplary embodiment may include elements that are
not
illustrated in the Figures.
In a first aspect, as shown in Figures 1A-B, the present invention may take
the form of
an anchoring guidewire 100 comprising: (a) an outer core 102, (b) an anchoring
basket 104,
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(c) a steerable tip 106, and (d) an actuator core 108. The outer core 102, the
anchoring basket
104 and the steerable tip 106 may be axially aligned with one another.
Further, the actuator
core 108 may be movably disposed within both the outer core 102 and the
anchoring basket
104 and may be coupled to the steerable tip 106. The total length of the
anchoring guidewire
100 may range from about 120 mm to about 10,000 mm.
As used herein, with respect to measurements and calculations, "about" means
+/- 5
%.
The outer core 102 may be made of, for example, polyurethane, a polyurethane
with
tungsten, gold, nitinol, platinum, stainless steel, stainless steel with
nickel, tungsten or any
other suitable material. The outer core 102 may have a diameter in the range
from about 0.25
mm to about 1 mm, and preferably in the range from about 0.254 mm to about
0.9652 mm.
In some embodiments, a plurality of radiopaque markers may be disposed on the
outer core
102. This plurality of radiopaque markers may be arranged such that the
plurality of
radiopaque makers are spaced apart by 1 cm, for example, starting at the
proximal end of the
anchoring basket 104 and moving in a proximal direction in a range up to about
20 mm along
the outer core 102.
In one embodiment, the anchoring basket 104 may include a plurality of strips
defined
in the outer core 102 adjacent to the steerable tip 106. These strips may be
created by laser
cutting the outer core 102. The strips may be substantially straight in a
first neutral state (as
shown in Figure 1A) and may bow out in a radial direction in a second
compressed state (as
shown in Figure 1B).
In another embodiment, the anchoring basket 104 may include a plurality of
wires
each with a proximal end and a distal end. This plurality of wires may be made
of, for
example, nitinol, titanium, titanium alloys, various plastics or any other
suitable material. In
one embodiment, each proximal end of the plurality of wires may be attached to
a first holder
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110 and each distal end of the plurality of wires may be attached to a second
holder 112. In
an alternative embodiment, the plurality of wires may be coupled directly to
the outer core
102 and to the steerable tip 106. The plurality of wires may be substantially
straight in a first
neutral state (as shown in Figure 1A) and bow out in a radial direction in a
second
compressed state as the first holder 110 and second holder 112 are moved
closer to one
another (as shown in Figure 1B). The anchoring basket 104 may have a diameter
in the
second compressed state ranging from about 3 mm to about 70 mm. The first
holder 110 may
be in mechanical communication with the outer core 102 and the second holder
112 may be
in mechanical communication with the steerable tip 106. In some embodiments,
the outer
core 102 may be physically coupled to the first holder 110 and the steerable
tip 106 may
likewise be physically coupled to the second holder 112.
The actuator core 108 may be movably disposed within the outer core 102 and
extend
through the anchoring basket 104 such that the actuator core 108 may be
coupled to the
steerable tip 106 and/or the second holder 112. In operation, the actuator
core 108 may cause
the anchoring basket 104 to move between the first neutral state and the
second compressed
state. Figure lA illustrates the first neutral state of the anchoring
guidewire 100, and Figure
1B illustrates the second compressed state of the anchoring guidewire 100. In
one
embodiment, the actuator core 108 may be positioned to allow it to cause the
steerable tip
206 to advance towards the outer core 102 until the anchoring basket 104 is in
the second
compressed state. In another embodiment, the actuator core 108 may be
positioned to allow
it to cause the second holder 112 to advance towards the first holder 110
until the anchoring
basket 104 is in the second compressed state.
Figures 2A-2C illustrate an example locking mechanism in accordance with one
embodiment of the invention. Specifically, the actuator core 108 may be in
physical
communication with a releasable locking mechanism to hold the anchoring basket
104 in the
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second compressed state. As shown in Figure 2A, the releasable locking
mechanism may
include a raised element or protrusion 114 coupled to the actuator core 108.
In the first
neutral state, the raised element or protrusion 114 may be configured to fit
within a slot 116
in the outer core 102. As shown in Figures 2B-2C, as the anchoring guidewire
100 moves
from the first neutral state to the second compressed state, the actuator core
108 and thereby
the raised element 114 may be pulled in a proximal direction relative to the
outer core 102,
then rotated such that an interference fit (shown in Figure 2C) with the outer
core 102
prevents the raised element 114 from moving distally. The net result of this
is that the
actuator core 108 may be locked in position and hold the anchoring basket 104
in the second
compressed state. When the plurality of wires 105 of the anchoring basket 104
are in the
second compressed state, the wires 105 are spring-loaded such that they seek
to return to the
first neutral state. As such, when a tension in the actuator core 108 is
removed, the second
holder 112 is positioned to allow it to cause the steerable tip 106 to advance
away from the
outer core 102 until the first neutral state is achieved.
In one embodiment, the actuator core 108 may have a stiffness such that the
actuator
core 108 may be capable of both pushing and pulling the steerable tip 106.
Here, the actuator
core 108 and/or the spring force in the plurality of wires may cause the wire
anchor basket
104 to return to the first neutral state.
The steerable tip 106 may have various stiffness and thickness to account for
different
use cases. For example, the steerable tip 106 may be thinner and/or less stiff
in a case where
the anchoring guidewire 100 must navigate a tight turn to advance to the
target vessel. In
another example, the steerable tip 106 may be thicker and/or stiffer in a case
where the target
vessel is less delicate and there is a more direct route to the target vessel.
The steerable tip
206 may have a length in the range from about 5 mm to about 200 mm.
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Figure 3 is a simplified flow chart illustrating a method according to an
exemplary
embodiment. Although the blocks are illustrated in a sequential order, these
blocks may also
be performed in parallel, and/or in a different order than those described
herein. Also, the
various blocks may be combined into fewer blocks, divided into additional
blocks, and/or
removed based upon the desired implementation.
At block 302, the method involves introducing the anchoring guidewire
according to
any one of the foregoing embodiments into any appropriate arterial
configuration, including a
synthetic lumen. At block 304 the method involves placing the actuator core
under tension
and causing the steerable tip to advance towards the outer core. At block 306,
the method
involves moving the anchoring basket from a first neutral state to a second
compressed state.
At block 308, the method involves locking the actuator core in place to hold
the anchoring
basket in the second compressed state. The actuator core may be locked in
place using the
example locking mechanism described above in relation to Figures 2A-2C, or
through some
other locking mechanism. In another embodiment, the method may further include
the step
of unlocking the actuator core. In still another embodiment, the method may
further include
removing tension from the actuator core and moving the anchoring basket from
the second
compressed state to the first neutral state.
While various aspects and embodiments have been disclosed herein, other
aspects and
embodiments will be apparent to those skilled in the art. All embodiments
within and between
different aspects of the invention can be combined unless the context clearly
dictates
otherwise. The various aspects and embodiments disclosed herein are for
purposes of
illustration and are not intended to be limiting, with the true scope and
spirit being indicated
by the following claims.
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