U.S. patent application number 10/318907 was filed with the patent office on 2004-06-17 for distal protection guidewire with nitinol core.
This patent application is currently assigned to SCIMED LIFE SYSTEMS, INC.. Invention is credited to Vrba, Anthony C..
Application Number | 20040116831 10/318907 |
Document ID | / |
Family ID | 32506500 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040116831 |
Kind Code |
A1 |
Vrba, Anthony C. |
June 17, 2004 |
Distal protection guidewire with nitinol core
Abstract
A guidewire having a proximal section, a distal section, and a
transition section is disclosed. In one exemplary embodiment of the
present invention, the proximal section may be formed of a
relatively stiff, inelastic material, whereas the distal section
may be formed of a relatively flexible, elastic material having
super-elastic properties. A coupling member may be placed adjacent
to the transition section to secure the proximal and distal
sections together.
Inventors: |
Vrba, Anthony C.; (Maple
Grove, MN) |
Correspondence
Address: |
CROMPTON, SEAGER & TUFTE, LLC
1221 NICOLLET AVENUE
SUITE 800
MINNEAPOLIS
MN
55403-2420
US
|
Assignee: |
SCIMED LIFE SYSTEMS, INC.
|
Family ID: |
32506500 |
Appl. No.: |
10/318907 |
Filed: |
December 13, 2002 |
Current U.S.
Class: |
600/585 |
Current CPC
Class: |
A61M 2025/0915 20130101;
A61M 2025/09075 20130101; A61M 2025/09141 20130101; A61F 2002/015
20130101; A61F 2230/0006 20130101; A61F 2/013 20130101; A61M
2025/09183 20130101; A61F 2002/018 20130101; A61F 2/011 20200501;
A61M 25/09 20130101; A61F 2230/008 20130101 |
Class at
Publication: |
600/585 |
International
Class: |
A61B 005/00 |
Claims
What is claimed is:
1. A guidewire, comprising: an elongate shaft including a proximal
section, a distal section, and a transition section, the proximal
section comprising a first material, the distal section comprising
a second material different from the first material; a coupling
member attached adjacent to the transition section, said coupling
member configured to secure the proximal section to the distal
section; and an embolic protection filter disposed on the
shaft.
2. The guidewire of claim 1, wherein the proximal section is
comprised of stainless steel.
3. The guidewire of claim 1, wherein the distal section is
comprised of a super-elastic material.
4. The guidewire of claim 1, wherein the distal section is
comprised of a linear-elastic material.
5. The guidewire of claim 1, wherein the distal section is
comprised of nickel-titanium alloy.
6. The guidewire of claim 1, wherein the transition section forms a
joint between the proximal and distal sections.
7. The guidewire of claim 6, wherein said joint is a butt
joint.
8. The guidewire of claim 6, wherein said joint is a lap joint.
9. The guidewire of claim 1, wherein the transition section
includes a necked-down portion.
10. The guidewire of claim 1, wherein the coupling member comprises
a tubular member.
11. The guidewire of claim 1, wherein the coupling member comprises
a nickel-chromium-molybdenum alloy tube.
12. The guidewire of claim 1, wherein the coupling member comprises
a polymeric member heat shrunk adjacent to the transition
section.
13. The guidewire of claim 1, further comprising a wire coil
disposed about a portion of said distal section.
14. The guidewire of claim 13, wherein said wire coil is formed
from a single continuous strand of wire helically disposed about a
portion of said distal section.
15. The guidewire of claim 13, wherein said wire coil comprises a
radiopaque material.
16. The guidewire of claim 1, further comprising a coil tip.
17. The guidewire of claim 16, wherein said coil tip includes a
hydrophilic coating.
18. The guidewire of claim 1, further comprising a safety
ribbon.
19. The guidewire of claim 1, further comprising a distal stop
disposed about a portion of said distal section.
20. A guidewire, comprising: an elongate shaft including a proximal
section formed of a relatively stiff, elastic material, a distal
section formed of a relatively flexible, elastic material, and a
transition section forming a joint between the proximal and distal
sections; a coupling member attached adjacent to the transition
section; and an embolic protection filter disposed on the
shaft.
21. The guidewire of claim 20, wherein the proximal section is
comprised of stainless steel.
22. The guidewire of claim 20, wherein the distal section is
comprised of a super-elastic material.
23. The guidewire of claim 20, wherein the distal section is
comprised of a linear-elastic material.
24. The guidewire of claim 20, wherein the distal section is
comprised of nickel-titanium alloy.
25. The guidewire of claim 20, wherein said joint is a butt
joint.
26. The guidewire of claim 20, wherein said joint is a lap
joint.
27. The guidewire of claim 20, wherein the transition section
includes a necked-down portion.
28. The guidewire of claim 20, wherein the coupling member
comprises a tubular member.
29. The guidewire of claim 20, wherein the coupling member
comprises a nickel-chromium-molybdenum alloy tube.
30. The guidewire of claim 20, wherein the coupling member
comprises a polymeric member heat shrunk adjacent to the transition
section.
31. The guidewire of claim 20, further comprising a wire coil
disposed about a portion of said distal section.
32. The guidewire of claim 31, wherein said wire coil is formed
from a single continuous strand of wire helically disposed about a
portion of said distal section.
33. The guidewire of claim 31, wherein said wire coil comprises a
radiopaque material.
34. The guidewire of claim 20, further comprising a coil tip.
35. The guidewire of claim 34, wherein said coil tip includes a
hydrophilic coating.
36. The guidewire of claim 20, further comprising a safety
ribbon.
37. The guidewire of claim 20, further comprising a distal stop
disposed about a portion of said distal section.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
intravascular guidewires. More specifically, the present invention
pertains to guidewires having super-elastic properties.
BACKGROUND OF THE INVENTION
[0002] Guidewires are frequently used to advance intravascular
devices such as stent delivery catheters, angioplasty catheters,
and atherectomy catheters within a patient's vasculature. Such
devices generally include a stiff proximal section to facilitate
pushability and torqueability, and a flexible distal section for
improved trackability. In some cases, the distal section of the
guidewire may have a reduced profile capable of placement beyond a
lesion or other stenosis within the body.
[0003] One important aspect of guidewire designs is the ability of
the distal section to undergo significant bending within the body
without permanently deforming the guidewire. Kinking results when
the stress within the guidewire exceeds the elastic limit of the
material, causing the material to plastically deform. As a result,
a residual strain is imparted to the guidewire preventing it from
fully recovering to its original shape. In certain circumstances,
the inability of the guidewire to return to its original shape may
diminish the performance and durability characteristics of the
guidewire.
SUMMARY OF THE INVENTION
[0004] The present invention relates generally to guidewires having
super-elastic properties. In an exemplary embodiment of the present
invention, a guidewire comprises a proximal section formed of a
first material, and a distal section formed of a second material
different from the first material. The proximal section of the
guidewire may be formed of a relatively stiff, inelastic material,
whereas the distal section may be formed of a relatively flexible,
elastic material. In some embodiments, the distal section may be
formed of a super-elastic material such as nickel-titanium alloy. A
coupling member may be attached to the guidewire adjacent a
transition section, securing the proximal and distal sections
together.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a plan view of an intravascular guidewire in
accordance with an exemplary embodiment of the present invention,
showing an embolic protection filter advanced along the guidewire;
and
[0006] FIG. 2 is a plan view of an intravascular guidewire in
accordance with another exemplary embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The following description should be read with reference to
the drawings, in which like elements in different drawings are
numbered in like fashion. The drawings, which are not necessarily
to scale, depict selected embodiments and are not intended to limit
the scope of the invention. Although examples of construction,
dimensions, and materials are illustrated for the various elements,
those skilled in the art will recognize that many of the examples
provided have suitable alternatives that may be utilized.
[0008] FIG. 1 is a plan view of an intravascular guidewire in
accordance with an exemplary embodiment of the present invention.
Guidewire 10 includes a proximal section 12, a distal section 14,
and a transition section 16 securing the proximal section 12 to the
distal section 14. Guidewire 10 is configured to support one or
more intravascular devices thereon, such as the embolic protection
filter 46 illustrated in FIG. 1.
[0009] The proximal section 12 of guidewire 10 may be formed of a
relatively stiff, inelastic material to enhance the pushability and
torqueability characteristics of the guidewire, and to support the
weight of various intravascular devices (e.g. balloon catheters,
stent delivery catheters, etc.) thereon. Proximal section 12 may be
formed of a metal such as type 304V stainless steel or
platinum.
[0010] The distal section 14 of guidewire 10 may be formed of a
relatively flexible, elastic material configured to impart
flexibility to the guidewire for enhanced tracking through the
tortuous vasculature. The distal section 14 may be formed from a
material having different mechanical properties than the proximal
section 12 of the guidewire 10. For example, the distal section 14
may be formed from a material having a lower modulus of elasticity
than the proximal section 12, thereby imparting greater flexibility
to the distal section 14. In one exemplary embodiment, the distal
section 14 may comprise a super-elastic and/or linear-elastic
material such as nickel-titanium alloy (Nitinol). Nickel-titanium
alloy exhibits pseudo-elastic capabilities at body temperature
(37.degree. C.), allowing it to undergo substantial bending with
relatively little residual strain. Unlike more commonly used
materials such as stainless steel, the use of super-elastic
materials such as Nitinol allows the distal section 14 to bend
significantly without permanently (i.e. plastically) deforming.
[0011] Guidewire 10 further includes a transition section 16
forming a joint between the proximal and distal sections 12, 14. As
shown in FIG. 1, for example, the distal end 20 of the proximal
section 12 may be coupled to the proximal end 22 of the distal
section 14, forming a butt joint therebetween. The proximal and
distal sections 12, 14 of the guidewire 10 may be bonded together
by adhesive, welding (e.g. resistance, laser, ultrasonic),
soldering, brazing, or any other suitable bonding technique.
[0012] In certain embodiments, guidewire 10 may include a coupling
member 24 further securing the proximal section 12 to the distal
section 14. The coupling member 24 may comprise a tubular member or
wire coil having an inner diameter configured to receive the distal
end 20 of the proximal section 12 and the proximal end 22 of the
distal section 14. The coupling member 24 may be formed from a
metal or metal alloy, including stainless steel, nickel-titanium
alloy, nickel-chromium alloy, nickel-chromium-iron alloy,
nickel-chromium-molybdenum, cobalt alloy, or nickel. For example,
in bonding a stainless steel proximal section 12 to a
nickel-titanium distal section 14, a nickel-chromium-molybdenum
based alloy such as INCONEL 625, ALLOY C276 or ALLOY B2 may be
used. INCONEL 625 is commercially available from the California
Fine Wire Company of Grover Beach, Calif. ALLOY C276 and B2 are
commercially available from the Fort Wayne Metals Research Products
Corporation of Fort Wayne, Ind.
[0013] In an alternative embodiment, the coupling member 24 may
comprise a polymeric material that can be heat shrunk adjacent the
ends 20, 22 of the proximal and distal sections 12, 14. For
example, a tubular segment formed of polytetraflouroethylene (PTFE)
can be placed adjacent the ends 20, 22 of the two sections 12, 14
and heated to a sufficient temperature, causing the material to
flow onto the ends 20, 22. In yet another embodiment, the coupling
member 24 may include a solder material that can be reflowed
adjacent the ends 20, 22 of the proximal and distal sections 12,
14.
[0014] In those embodiments utilizing a coupling member 24, the
ends 20, 22 of the proximal and distal sections 12, 14 may be
tapered or reduced in diameter such that the profile of the
guidewire 10 at the transition section 16 is substantially similar
to the profile of the proximal and distal sections 12, 14
immediately adjacent the transition section 16. As shown in FIG. 1,
for example, the ends 20, 22 of the proximal and distal sections
12, 14 may include a necked-down portion 26 reducing the outer
diameter of the sections 12, 14 at the transition section 16.
[0015] The distal section 14 may also include a shaping ribbon 28.
The shaping ribbon 28 connects the distal end 30 of the distal
section 14 to a coil tip 34 disposed at the distal end 32 of the
guidewire 10. The shaping ribbon 28 may be formed of metal (e.g.
type 304V stainless steel), a polymer, or any other suitable
material.
[0016] Coil tip 34 is generally circular in shape, and includes a
proximal portion 36 forming a rearwardly facing shoulder, and a
distal portion 38. The coil tip 34 may be substantially round, and
may include a hydrophilic coating to reduce tissue damage within
the body.
[0017] Guidewire 10 may also include a wire coil 40 disposed at
least in part about the distal section 14. The wire coil 40 may be
attached at a proximal end 42 to the distal section 14, and at a
distal end 44 to the proximal portion 36 of coil tip 34. The wire
coil 40 may be formed from a single, continuous strand of wire
helically disposed about the distal section 14. In certain
embodiments, the wire coil 40 may comprise a radiopaque material
such as gold, platinum, or tantalum, allowing the operator to
fluoroscopically judge the location of the guidewire 10 within the
body.
[0018] An intravascular device such as the embolic protection
filter 46 depicted in FIG. 1 may be placed on the guidewire 10. The
embolic protection filter 46 may include a tubular base member 48,
which allows the filter 46 to slide and rotate about the guidewire
10. In use, the guidewire 10 may be percutaneously inserted into a
blood vessel, and advanced to a desired location within the body
(e.g. a coronary artery). Once positioned, the embolic protection
filter 46 can then be advanced over the guidewire 10 via a delivery
catheter, and placed at a location downstream a lesion or other
stenosis within the vessel. An intravascular device such as an
angioplasty balloon can then be advanced along the guidewire 10 to
a location upstream of the embolic protection filter 46 to perform
a therapeutic procedure such as percutaneous transluminal coronary
angioplasty. A stent may also be advanced along the guidewire 10
and deployed within the body, if desired.
[0019] In an alternative embodiment (not shown), the embolic
protection filter 46 may be fixedly secured to the distal section
14 of the guidewire 10 prior to insertion within the patient. In a
fixed configuration, the guidewire 10 and attached embolic
protection filter are both loaded into the delivery catheter prior
to being inserted into the body. The guidewire 10 and attached
filter are simultaneously inserted into the body, and then advanced
to the site of the lesion. Once positioned distal the lesion, the
guidewire can then be used to advance other intravascular devices
to the site.
[0020] To collect embolic debris dislodged during the therapeutic
procedure, embolic protection filter 46 may include a filter mesh
or membrane 50 coupled to a proximal support hoop 52. The proximal
support hoop 52 forms a mouth or opening on the embolic protection
filter 46, and is biased to radially expand within the vessel when
removed from the delivery catheter. The filter mesh or membrane 50
may include several openings or pores 54 configured to filter
embolic debris while permitting the perfusion of blood through the
blood vessel. A tether line 56 connects the embolic protection
filter 46 to the tubular base member 48.
[0021] Embolic protection filter 46 may further include a nose cone
58. Nose cone 58 is formed from an enlarged diameter distal portion
of the tubular base member 48. The nose cone 58 is tapered distally
to provide a relatively uniform profile transition between the
proximal end 42 of the wire coil 40 and the embolic protection
filter 46. A reduced inner diameter portion 60 on the distal end 62
of the nose cone 58 is adapted to slide over the proximal end 42 of
the wire coil 40. In use, the proximal end 42 of the wire coil 40
acts as a distal stop, preventing the embolic protection filter 46
from being advanced beyond the distal end 32 of the guidewire
10.
[0022] FIG. 2 is a plan view of an intravascular guidewire in
accordance with another exemplary embodiment of the present
invention. Guidewire 110 includes a proximal section 112, a distal
section 114, and a transition section 116. As with the embodiment
described above with respect to FIG. 1, guidewire 110 is configured
to support one or more intravascular devices thereon.
[0023] The proximal section 112 of guidewire 110 may comprise a
relatively stiff, inelastic material (e.g. type 304V stainless
steel), whereas the distal section 114 may comprise a relatively
flexible, super-elastic material such as nickel-titanium alloy. The
distal end 120 of the proximal section 112 may include a notch
configured to align with a correspondingly dimensioned notch on the
proximal end 122 of the distal section 114. Together, the notches
form a lap joint 162 between the proximal and distal sections 112,
114.
[0024] A coupling member 124 may also be placed adjacent the ends
120, 122 of the proximal and distal sections 112, 114 at the
transitional section 116. In those embodiments utilizing a coupling
member 124, the ends 120, 122 of the proximal and distal sections
112, 114 may be tapered or reduced in diameter such that the
profile of the guidewire 110 at the transition section 116 is
substantially similar to the profile of the proximal and distal
sections 112, 114 immediately adjacent the transition section
116.
[0025] A wire coil 140 may be placed about a portion of the distal
section 114. Wire coil 140 has a proximal end 142 and a distal end
144. The proximal end 142 of wire coil 140 may be attached to a
shoulder 164 located on the distal section 114 of the guidewire
110. The distal end 144 of wire coil 140, in turn, may be attached
to the proximal portion 136 of the coil tip 134. A shaping ribbon
128 connecting the distal end 130 of the distal section 114 to the
proximal portion 136 of the coil tip 134 may also be used, if
desired.
[0026] Guidewire 110 further includes a distal stop 166 disposed
about a portion of the distal section 114. Distal stop 166
comprises an object having an outer diameter slightly larger than
the inner diameter of the intravascular device. In use, the distal
stop 166 prevents movement of the intravascular device beyond the
distal end 132 of the guidewire 110.
[0027] Attachment of the distal stop 166 to the guidewire 110 may
be accomplished by any number of suitable attachment means,
including crimping, soldering, brazing, welding, adhesion or any
combination thereof. Furthermore, the distal stop 166 may be formed
from any number of suitable materials, such as stainless steel or
nickel-titanium alloy. In one implementation, the distal stop 166
may be formed by heat bonding a polymeric object about the distal
section 114.
[0028] Although the exemplary embodiments illustrated in FIGS. 1-2
depict a guidewire 10, 110 having a solid core (i.e. solid
cross-section), it should be understood that other configurations
are possible without deviating from the scope of the invention. For
example, the proximal and distal sections may have a hollow
cross-sectional area, forming a guide catheter or the like.
[0029] Having thus described the several embodiments of the present
invention, those of skill in the art will readily appreciate that
other embodiments may be made and used which fall within the scope
of the claims attached hereto. Numerous advantages of the invention
covered by this document have been set forth in the foregoing
description. It will be understood that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size and arrangement of parts
without exceeding the scope of the invention.
* * * * *