Patent Description:
A guide wire used for inserting a catheter or the like into a blood vessel is known. In such a guide wire, a small curve, or the like is formed on a distal end portion of the guide wire for the purpose of improving blood vessel selectivity to smoothly lead the guide wire to a target site in a blood vessel in some cases. For example, Patent Literature <NUM> to <NUM> discloses a guide wire in which shaping of a distal end portion is facilitated by joining a distal end-side shaft (ribbon) made of stainless steel to a distal end of a long shaft (core) made of a nickel-titanium alloy. Further state-of-the-art guide wires are known from <CIT>, <CIT> and <CIT>.

However, the guide wires described in Patent Literatures <NUM> to <NUM> have had problems that a connection between the long shaft and the distal end-side shaft is not yet easy to shape due to the difference in plasticity between the long shaft formed of a nickel-titanium alloy and the distal end-side shaft made of stainless steel. In addition, the guide wires described in Patent Literatures <NUM> to <NUM> have had problems that a part locally susceptible to deformation, e.g. a vicinity of the connection between the long shaft and the distal end-side shaft, or the like, is caused due to the difference in rigidity between the long shaft and the distal end-side shaft.

Incidentally, such problems are not limited to vascular systems, and are common to guide wires to be inserted into each organ in a human body, such as a lymphatic system, a biliary system, a urinary system, a respiratory system, a digestive system, a secretory gland, and a genital organ. In addition, such a problem is not limited to the guide wire including the shaft made of a nickel-titanium alloy and the shaft made of stainless steel, and is common to guide wires formed by joining a plurality of core shafts made of materials having different characteristics.

The disclosed embodiments have been made to solve the aforementioned problems, and an object of the disclosed embodiments is to provide a guide wire in which a distal end portion can be easily shaped and durability is improved.

The disclosed embodiments have been made to solve at least a part of the aforementioned problems, and can be achieved as the following aspects.

Incidentally, the disclosed embodiments can be achieved in various aspects, e.g. in a form of a core shaft product composed of a plurality of core shafts used in a guide wire, a method for manufacturing a guide wire, or the like.

<FIG> is a partial sectional view illustrating an overall configuration of a guide wire <NUM> according to the first embodiment. The guide wire <NUM> is e.g. a medical appliance used for inserting a catheter into a blood vessel, and includes a first core shaft <NUM>, a coil body <NUM>, a second core shaft <NUM>, a covering portion <NUM>, a distal end-side fixation portion <NUM>, a proximal end-side fixation portion <NUM>, and an intermediate fixation portion <NUM>. In <FIG>, an axis passing through a center of the guide wire <NUM> is represented by an axis line O (dot and dash line). In the following examples, all of an axis passing through a center of the first core shaft <NUM> on a proximal end side of a first large-diameter portion <NUM>, an axis passing through a center of the coil body <NUM>, and an axis passing through a center of the covering portion <NUM> coincide with the axis line O. However, each of the axis passing through the center of the first core shaft <NUM>, the axis passing through the center of the coil body <NUM>, and the axis passing through the center of the covering portion <NUM> may be inconsistent with the axis line O.

In addition, XYZ axes that are orthogonal to each other are illustrated in <FIG>. The X axis corresponds to the axis direction of the guide wire <NUM>, the Y axis corresponds to a height direction of the guide wire <NUM>, and the Z axis corresponds to a width direction of the guide wire <NUM>. The left side (-X axis direction) of <FIG> is referred to as "distal end side" of the guide wire <NUM> and each component, and the right side of <FIG> (+X axis direction) is referred to as "proximal end side" of guide wire <NUM> and each component. In addition, regarding the guide wire <NUM> and each component, the end portion positioned on the distal end side is referred to as "distal end portion" or simply "distal end", the end portion positioned on the proximal end side is referred to as "proximal end portion" or simply "proximal end". In the first embodiment, the distal end side corresponds to "farther side", and the proximal end side corresponds to "nearer side". These regards are also common to the figures illustrating the overall configuration in <FIG> and the following figures.

The first core shaft <NUM> is a long, tapered member with a large diameter on the proximal end side and a small diameter on the distal end side. The first core shaft <NUM> is made of a superelastic material e.g. a NiTi (nickel-titanium) alloy, or an alloy of NiTi and another metal. The first core shaft <NUM> has a small-diameter portion <NUM>, a first decreasing-diameter portion <NUM>, a first large-diameter portion <NUM>, a second decreasing-diameter portion <NUM>, a second large-diameter portion <NUM>, in this order from the distal end side to the proximal end side. An outer diameter and a length of each portion can be arbitrarily determined.

<FIG> is a partial sectional view illustrating the distal end side of the guide wire <NUM>. <FIG> is a sectional view illustrating the guide wire <NUM> taken along line A-A (<FIG>). In <FIG>, the sectional view taken along line A-A is illustrated on an upper column, and a partial enlarged view of the vicinity of the joint part JP is illustrated on a lower column. The XYZ axes illustrated in <FIG> and <FIG> correspond to the XYZ axes respectively illustrated in <FIG>. The same applies to the figures with XYZ axes in <FIG> and the following figures.

The small-diameter portion <NUM> of the first core shaft <NUM> is disposed on the distal end side of the first core shaft <NUM>. The small-diameter portion <NUM> is a portion where the outer diameter of the first core shaft <NUM> is the smallest, and has a substantially rectangular transverse sectional shape as illustrated in <FIG>. In <FIG>, the transverse sectional shape of the small-diameter portion <NUM> is illustrated as a substantially square shape with substantially same side lengths in the Y-axis direction and the Z-axis direction. Incidentally, the transverse sectional shape of the small-diameter portion <NUM> may be a substantially rectangular shape with a major side and a minor side, or a substantially rectangular shape with R-chamfered corners or C-chamfered corners.

The first decreasing-diameter portion <NUM> is disposed between the small-diameter portion <NUM> and the first large-diameter portion <NUM>. The first decreasing-diameter portion <NUM> has a substantially truncated cone shape with an outer diameter reducing from the proximal end side to the distal end side. The first large-diameter portion <NUM> is disposed between the first decreasing-diameter portion <NUM> and the second decreasing-diameter portion <NUM>. The first large-diameter portion <NUM> has a substantially cylindrical shape with a certain outer diameter larger than an outer diameter of the small-diameter portion <NUM>. The second decreasing-diameter portion <NUM> is disposed between the first large-diameter portion <NUM> and the second large-diameter portion <NUM>. The second decreasing-diameter portion <NUM> has a substantially truncated cone shape with an outer diameter reducing from the proximal end side to the distal end side. The second large-diameter portion <NUM> is disposed on the proximal end side of the first core shaft <NUM>. The second large-diameter portion <NUM> has a substantially cylindrical shape having a certain outer diameter equivalent to the largest outer diameter of the first core shaft <NUM>.

The outer side faces of the small-diameter portion <NUM>, the first decreasing-diameter portion <NUM>, and the first large-diameter portion <NUM> are covered by the coil body <NUM> described later. On the other hand, the second decreasing-diameter portion <NUM> and the second large-diameter portion <NUM> are not covered by the coil body <NUM> but are exposed from the coil body <NUM>. The second large-diameter portion <NUM> is used when an operator grasps the guide wire <NUM>.

The coil body <NUM> has a substantially cylindrical shape formed by spirally winding a wire <NUM> around the first core shaft <NUM> and the second core shaft <NUM>. The wire <NUM> forming the coil body <NUM> may be a solid wire composed of one wire, or a twisted wire obtained by twisting a plurality of wires. When the wire <NUM> is a solid wire, the coil body <NUM> is configured as a single coil, and when the wire <NUM> is the twisted wire, the coil body <NUM> is configured as a hollow twisted wire coil. Alternatively, the coil body <NUM> may be configured by combining the single coil and the hollow twisted wire coil. The wire diameter of the wire <NUM> and an average coil diameter in the coil body <NUM> (average diameter of the outer diameter and the inner diameter of the coil body <NUM>) can be arbitrarily determined.

The wire <NUM> can be made of, for example, a stainless steel alloy such as SUS304 and SUS316, a superelastic alloy such as a NiTi alloy, a piano wire, a radiolucent alloy such as nickel-chromium alloy and cobalt alloy, gold, platinum, tungsten, or a radiopaque alloy such as an alloy including the aforementioned elements (e.g. platinum-nickel alloy). Incidentally, the wire <NUM> may be made of a known material other than the aforementioned materials.

The second core shaft <NUM> is a long member having a certain outer diameter from the proximal end side to the distal end side, and has a substantially elliptical transverse sectional shape with a major axis and a minor axis as illustrated in <FIG>. The second core shaft <NUM> is adjacent to the small-diameter portion <NUM> of the first core shaft <NUM> such that the major axis is oriented in the Y axis direction and the minor axis is oriented in the Z axis direction. The second core shaft <NUM> is made of a material that is more susceptible to plastic deformation than the first core shaft <NUM>, e.g. a stainless steel alloy such as SUS304 and SUS316. The second core shaft <NUM> is also referred to as "ribbon". Incidentally, the second core shaft <NUM> may be configured such that only a part of the proximal end side corresponding to the joint part JP has a substantially elliptical transverse sectional shape illustrated in <FIG>, and a part of the distal end side of the joint part JP has a transverse sectional shape different from the substantially elliptical shape (e.g. a substantially circular shape). In addition, the second core shaft <NUM> may be oriented in a different direction from <FIG>, e.g. the minor axis is oriented in the Y axis direction, and the major axis is oriented in the Z axis direction.

As illustrated in <FIG>, the proximal end side of the second core shaft <NUM> is joined to the small-diameter portion <NUM> on the distal end side of the first core shaft <NUM>. This joining can be performed in such a way that a gap between the first core shaft <NUM> (small-diameter portion <NUM>) and the second core shaft <NUM> that are adjacent to each other is filled with a joining agent <NUM> and the joining agent <NUM> is hardened as illustrated in <FIG>. As the joining agent <NUM>, e.g. a metal solder such as silver solder, gold solder, zinc, Sn-Ag alloy, and Au-Sn alloy, or an adhesive such as epoxy adhesive can be used. In <FIG> and <FIG>, the joint part between the first core shaft <NUM> and the second core shaft <NUM> is referred to as "joint part JP". The distal end side of the second core shaft <NUM> is fixed by the distal end-side fixation portion <NUM> described later.

In the example of <FIG>, the second core shaft <NUM> is joined to the first core shaft <NUM> such that a position of the proximal end portion of the second core shaft <NUM> and a position of the proximal end portion of the small-diameter portion <NUM> coincide with each other in the axis line O (X axis) direction. However, the position of the proximal end portion of the second core shaft <NUM> and the position of the proximal end portion of the small-diameter portion <NUM> in the axis line O direction may be different from each other. For example, the proximal end portion of the second core shaft <NUM> may be positioned on the -X axis direction side of the proximal end portion of the small-diameter portion <NUM>.

<FIG> is a perspective view illustrating a schematic configuration of the covering portion <NUM>. The covering portion <NUM> according to the first embodiment is a multi-thread coil obtained by winding eight wires <NUM>, and is less susceptible to plastic deformation than the second core shaft <NUM> and more susceptible to plastic deformation than the first core shaft <NUM>. The covering portion <NUM> can be formed e.g. in such a way that the eight wires <NUM> are tightly twisted around a cored bar so as to be in contact with each other, then a residual stress is removed using a known heat treatment method, and the cored bar is drawn out. The covering portion <NUM> formed in this way is a multi-thread coil having an inner cavity <NUM> (<FIG>: dashed line) as illustrated in <FIG>. A material of the wire <NUM> may be the same as or different from that of the wire <NUM>.

Incidentally, for the covering portion <NUM>, any aspect can be adopted as long as the covering portion <NUM> is configured to be less susceptible to plastic deformation than the second core shaft <NUM> and more susceptible to plastic deformation than the first core shaft <NUM>. For example, a number of the wires constituting the covering portion <NUM> is not limited to eight, and can be arbitrarily determined. The covering portion <NUM> is not limited to the multi-thread coil, and may be a single-thread coil formed of one wire, or a tubular member made of a resin or a metal and formed into a tube shape, or alternatively may be coated with a hydrophobic resin material, a hydrophilic resin material, or a mixture thereof.

As illustrated in <FIG> and <FIG>, inside the coil body <NUM>, the covering portion <NUM> is arranged so as to cover a part of the distal end side of the first core shaft <NUM>, the joint part JP, and the second core shaft <NUM>. In other words, the first core shaft <NUM> and second core shaft <NUM> joined to each other pass through the inner cavity <NUM> of the covering portion <NUM> and extend in the axis line O direction. The distal end portion of the covering portion <NUM> is fixed by the distal end-side fixation portion <NUM> described later. The proximal end portion of the covering portion <NUM> is disposed in the vicinity of the center of the first decreasing-diameter portion <NUM> of the first core shaft <NUM> (<FIG>). Incidentally, the proximal end portion of the covering portion <NUM> may or may not be fixed to the first decreasing-diameter portion <NUM> of the first core shaft <NUM> using any joining agent.

The distal end-side fixation portion <NUM> is disposed on the distal end portion of the guide wire <NUM> and integrally holds the distal end portion of the second core shaft <NUM>, the distal end portion of the coil body <NUM>, and the distal end portion of the covering portion <NUM>. The distal end-side fixation portion <NUM> can be formed from any joining agent, e.g. a metal solder such as silver solder, gold solder, zinc, Sn-Ag alloy, and Au-Sn alloy, or an adhesive such as epoxy adhesive. The proximal end-side fixation portion <NUM> is disposed on the base end portion of the first large-diameter portion <NUM> of the first core shaft <NUM> and integrally holds the first core shaft <NUM> and the proximal end portion of the coil body <NUM>. The proximal end-side fixation portion <NUM> can be formed from any joining agent in the same manner as for the distal end-side fixation portion <NUM>. For the proximal end-side fixation portion <NUM> and the distal end-side fixation portion <NUM>, the same joining agent or different joining agents may be used.

The intermediate fixation portion <NUM> integrally holds the coil body <NUM> and the first core shaft <NUM> in the vicinity of the intermediate portion of the coil body <NUM> in the axis line O direction. The intermediate fixation portion <NUM> can be formed from any joining agent in the same manner as for the distal end-side fixation portion <NUM>. For the intermediate fixation portion <NUM> and the distal end-side fixation portion <NUM>, the same joining agent or different joining agents may be used. Although one intermediate fixation portion <NUM> has been described as an example in <FIG>, a plurality of intermediate fixation portions <NUM> may be disposed on the guide wire <NUM>.

Herein, as illustrated in <FIG>, a part where the joint part JP between the first core shaft <NUM> and the second core shaft <NUM> is covered by the covering portion <NUM> is referred to as "second region R2", a part where the second core shaft <NUM> on the distal end side of the joint part JP is covered by the covering portion <NUM> is referred to as the "first region R1", a part where the first core shaft <NUM> (first decreasing-diameter portion <NUM>) on the proximal end side of the joint part JP is covered by the covering portion <NUM> is referred to as "third region R3", and a part where the first core shaft <NUM> is exposed from the covering portion <NUM> is referred to as "fourth region R4". That means, in the first embodiment, the first region R1, the second region R2, the third region R3, and the fourth region R4 are disposed in this order from the distal end side to the proximal end side of the guide wire <NUM>. In other words, the first region R1 is positioned on the most distal side, the second region R2 is positioned on the proximal end side of the first region R1, the third region R3 is positioned on the proximal end side of the second region R2, and the fourth region R4 is positioned on the proximal end side of the third region R3 (most proximal end side).

As described above, the first core shaft <NUM> is made of a superelastic material, and the second core shaft <NUM> is made of a material more susceptible to plastic deformation than of the first core shaft <NUM>. The covering portion <NUM> is configured to be less susceptible to plastic deformation than the second core shaft <NUM> and more susceptible to plastic deformation than the first core shaft <NUM>. Thus, a relationship of each member on the susceptibility to plastic deformation is expressed as "the second core shaft <NUM> > the covering portion <NUM> > the first core shaft <NUM>". In addition, as illustrated in <FIG>, the diameter of the first core shaft <NUM> (first decreasing-diameter portion <NUM>) exposed from the covering portion <NUM> increases from the distal end side to the proximal end side, and becomes substantially the same as the outer diameter of the covering portion <NUM> in the vicinity of the boundary with the first large-diameter portion <NUM>. As a result, the aforementioned susceptibility of each region in the guide wire <NUM> to plastic deformation gradually decreases from the first region R1 to the fourth region R4 in the order of (the first region R1 > the second region R2 > the third region R3 > the fourth region R4).

As described above, in the guide wire <NUM> according to the first embodiment, the first region R1 more susceptible to plastic deformation than the second region R2 adjacent to the proximal end side (+X axis direction) is disposed on the distal end side (-X axis direction) of the guide wire <NUM> (<FIG>). Thus, the distal end portion of the guide wire <NUM> can be easily shaped by squeezing the distal end portion of the guide wire <NUM> with e.g. fingertips or a tip of a syringe needle. In addition, a covering portion <NUM> for covering the joint part JP between the first core shaft <NUM> (small-diameter portion) and the second core shaft <NUM>, and at least a part of the second core shaft <NUM> on the distal end side of the joint part JP is disposed on both the first region R1 and the second region R2 (<FIG>: first region R1 and second region R2). Owing to this covering portion <NUM>, a rigidity gap between the first and second core shafts <NUM> and <NUM> having different rigidities can be reduced, and therefore the joint part JP of the first and second core shafts <NUM> and <NUM> can be more easily shaped compared to a configuration without the covering portion <NUM>. Furthermore, reduction in the rigidity gap between the first and second core shafts <NUM> and <NUM> in the covering portion <NUM> makes it possible to protect a part locally susceptible to deformation in the vicinity of the joint part JP, e.g. a part <NUM> of the second core shaft on the distal end side of the joint part JP (<FIG>), a part <NUM> of the first core shaft <NUM> on the proximal end side of the joint part JP (<FIG>), or the like, to prevent breakage of the first and second core shafts <NUM> and <NUM>, so that durability of the guide wire <NUM> can be prevented.

Additionally, in the guide wire <NUM> according to the first embodiment, the distal end portion of the covering portion <NUM> is fixed by the distal end-side fixation portion <NUM> for fixing the distal end portion of the second core shaft <NUM> (<FIG> and <FIG>). That means, in the guide wire <NUM> according to the first embodiment, the covering portion <NUM> is formed on the second core shaft <NUM> and also its distal end. In such a way, the second core shaft <NUM> made of a material susceptible to plastic deformation and also its distal end can be protected to prevent breakage of the second core shaft <NUM> accompanying shaping and use, so that durability of the guide wire <NUM> can be further improved.

Furthermore, in the guide wire <NUM> according to the first embodiment, the third region R3 less susceptible to plastic deformation than the second region R2 is disposed on the proximal end side of the second region R2 (<FIG>: third region R3). Thereby, the first core shaft <NUM> positioned on the proximal end side of the joint part JP between the first and second core shafts <NUM> and <NUM> can be protected to prevent breakage of the first core shaft <NUM> accompanying shaping and use, so that durability of the guide wire <NUM> can be further improved. Furthermore, the fourth region R4 less susceptible to plastic deformation than the third region R3 is disposed on the proximal end side of the third region R3 (<FIG>: the fourth region R4). Thereby, breakage of the first core shaft <NUM> can be further improved, so that durability of the guide wire <NUM> can be further improved. In addition, in the fourth region R4, the first core shaft <NUM> is exposed from the covering portion <NUM>. Thus, a manufacturing cost of the guide wire <NUM> can be reduced e.g. compared to a configuration that the covering portion <NUM> is formed on the coil body <NUM> and also its proximal end portion.

Furthermore, in the guide wire <NUM> according to the first embodiment, a transverse sectional shape of the of the first core shaft <NUM> (<FIG>: small-diameter portion <NUM>) on the joint part JP between the first and second core shafts <NUM> and <NUM> is a substantially rectangular shape, a transverse sectional shape of the second core shaft <NUM> (<FIG>: second core shaft <NUM>) is a substantially elliptical shape, and therefore the shapes of them are different. Thereby, as illustrated in <FIG>, a contact face between the first and second core shafts <NUM> and <NUM> adjacent to each other on the joint part JP increases compared to a case that the small-diameter portion <NUM> and the second core shaft <NUM> have the same shape (e.g. circle, rectangle, or the like). According to the guide wire <NUM> having this configuration, a joining strength between the first and second core shafts <NUM> and <NUM> can be improved by filling this contact face as a joining face L1 (<FIG>) with the joining agent <NUM>.

<FIG> is a partial sectional view illustrating a distal end side of a guide wire 1A according to the second embodiment. <FIG> is a sectional view illustrating the guide wire 1A according to the second embodiment taken along line B-B (<FIG>). In <FIG>, a partial enlarged view of the distal end side of the guide wire 1A is illustrated on the upper column, a partial enlarged view of a vicinity of a joint part JPAis illustrated on the lower column. In the guide wire 1A according to the second embodiment, the joint part between the first and second core shafts <NUM> and <NUM> is disposed between the first decreasing-diameter portion <NUM> of the first core shaft <NUM> and the proximal end portion of the second core shaft <NUM>. The first decreasing-diameter portion <NUM> gradually decreases in the outer diameter from the proximal end side to the distal end side (<FIG>, lower column), and has a substantially circle transverse sectional shape (<FIG>). As illustrated in the lower column of <FIG>, the joint part JPAcan be formed by filling the gap between the first decreasing-diameter portion <NUM> and the second core shaft <NUM> adjacent to each other with the joining agent <NUM> and hardening the joining agent <NUM>. For the joining agent <NUM>, the metal solder or the adhesive described as examples in the first embodiment can be used. The joining agent <NUM> according to the second embodiment may be the same as or different from that in the first embodiment.

In the example on the lower column of <FIG>, the gap between the small-diameter portion <NUM> of the first core shaft <NUM> and the second core shaft <NUM> is a void without the joining agent <NUM>. However, the void between the small-diameter portion <NUM> and the second core shaft <NUM> may be eliminated by filling this gap with the joining agent <NUM> and hardening the joining agent <NUM>. As described above, in the second embodiment, the joint part JPA includes a part where the small-diameter portion <NUM> and the second core shaft <NUM> are adjacent to each other, and the second region R2 includes a part where the small-diameter portion <NUM> and the second core shaft <NUM> are adjacent to each other (<FIG>, upper column: second region R2).

As described above, also in the guide wire 1A according to the second embodiment, the same effect as in the first embodiment described above can be accomplished. Furthermore, in the guide wire 1A according to the second embodiment, the first decreasing-diameter portion <NUM> having a decreasing outer diameter is formed on the distal end side of the first core shaft <NUM>, and the joint part JPA to which the second core shaft <NUM> is joined is disposed on this first decreasing-diameter portion <NUM>. Thus, as illustrated on the lower column of <FIG>, even if the first and second core shafts <NUM> and <NUM> adjacent to each other on the joint part JPA have the same transverse sectional shape (<FIG>), the durability of the guide wire 1A can be improved because the joint part JPA has a joint on the large-diameter part of the first core shaft <NUM>.

<FIG> is a partial sectional view illustrating a distal end side of a guide wire 1B according to the third embodiment. In the guide wire 1B according to the third embodiment, a distal end region R0 is disposed on the distal end side of the first region R1. In the distal end region R0, the second core shaft <NUM> is not covered by a covering portion 40B but is exposed from the covering portion 40B. Specifically, the covering portion 40B according to the third embodiment has a length in the axis line O direction (X-axis direction) shorter than the length of the covering portion <NUM> according to the first embodiment, and is arranged so as to cover not the whole second core shaft <NUM> but a part on the proximal end side of the second core shaft <NUM>. The proximal end portion of the covering portion 40B is fixed to the first decreasing-diameter portion <NUM> of the first core shaft <NUM> using any joining agent. The distal end portion of the covering portion 40B is not fixed to the distal end-side fixation portion 51B and opens in the example in <FIG>. Incidentally, a distal end portion of the covering portion 40B may be fixed to the second core shaft <NUM> using any joining agent.

In the third embodiment as described above, the distal end region R0, the first region R1, the second region R2, the third region R3, and the fourth region R4 are disposed in this order from the distal end side to the proximal end side of the guide wire 1B. As described above, a relationship of each member on the susceptibility to plastic deformation is expressed as (the second core shaft <NUM> > the covering portion 40B, > the first core shaft <NUM>). Thus, the distal end region R0 not covered by the covering portion 40B is more susceptible to plastic deformation than the first region R1 covered by the covering portion 40B. That means the susceptibility of each region in the guide wire 1B to plastic deformation gradually decreases from the distal end region R0 to the fourth region R4 in the order of (the distal end region R0 > the first region R1 > the second region R2 > the third region R3 > the fourth region R4).

As described above, also in the guide wire 1B according to the third embodiment, the same effect as in the aforementioned first embodiment can be accomplished. Furthermore, in the guide wire 1B according to the third embodiment, the distal end region R0 more susceptible to plastic deformation than the first region R1 is disposed on the distal end side of the first region. This makes it possible to further facilitate shaping of the distal end portion of the guide wire 1B. In addition, since the susceptibility of each region in the guide wire 1B to plastic deformation gradually increases from the fourth region R4 on the proximal end side to the distal end region R0 on the distal end side, it is possible to provide the guide wire 1B in which the distal end side is more easily shaped while preventing breakage of the first and second core shafts <NUM> and <NUM> on the proximal end side.

<FIG> is a partial sectional view illustrating the distal end side of the guide wire 1C according to the fourth embodiment. In the guide wire 1C according to the fourth embodiment, the third region R3 is not formed. Specifically, the covering portion 40C according to the fourth embodiment has a length in the axis line O direction (X-axis direction) shorter than of the covering portion <NUM> according to the first embodiment and does not cover the first core shaft <NUM> (first decreasing-diameter portion <NUM>) on the proximal end side of the joint part JP between the first and second core shafts <NUM> and <NUM>. In other words, the first core shaft <NUM> (first decreasing-diameter portion <NUM>) on the proximal end side of the joint part JP is not covered by the covering portion 40C but is exposed. Incidentally, a proximal end portion of the covering portion 40C may be fixed to at least one end of the small-diameter portion <NUM> of the first core shaft <NUM> and the second core shaft <NUM> using any joining agent.

In the fourth embodiment as described above, the first region R1, the second region R2, and the fourth region R4 are disposed in this order from the distal end side to the proximal end side of the guide wire 1C. The susceptibility of each region to plastic deformation gradually decreases from the first region R1 to the fourth region R4, expressed as (the first region R1 > the second region R2 > the fourth region R4). Thus, the guide wire 1C according to the fourth embodiment accomplishes the same effect as in the first embodiment.

<FIG> is a partial sectional view illustrating an overall configuration of a guide wire 1D according to the fifth embodiment. In the guide wire 1D according to the fifth embodiment, the fourth region R4 is not formed. Specifically, a first core shaft 10D according to the fifth embodiment does not include the second decreasing-diameter portion <NUM> and the second large-diameter portion <NUM>. In addition, a covering portion 40D has a length in the axis line O direction (X-axis direction) longer than of the covering portion <NUM> according to the first embodiment, and is arranged so as to cover the whole first core shaft 10D positioned inside the coil body <NUM>. A distal end portion of the covering portion 40D is fixed by the distal end-side fixation portion <NUM> in the same manner as in the first embodiment. In addition, a proximal end portion of the covering portion 40D is fixed together with the coil body <NUM> and a proximal end portion of the first core shaft 10D by the proximal end-side fixation portion 52D.

In the fifth embodiment as described above, the first region R1, the second region R2, and the third region R3 are disposed in this order from the distal end side to the proximal end side of the guide wire 1D. The susceptibility of each region to plastic deformation gradually decreases from the first region R1 to the third region R3 in the order of (the first region R1 > the second region R2 > the third region R3). Thus, the guide wire 1D according to the fifth embodiment accomplishes the same effect as in the first embodiment.

<FIG> is a sectional view illustrating a guide wire 1E according to the sixth embodiment taken along line A-A (<FIG>). In <FIG>, the sectional view taken along line A-A is illustrated on the upper column, a partial enlarged view of the vicinity of a joint part JPE is illustrated on the lower column. In the guide wire 1E according to the sixth embodiment, a first core shaft 10E (small-diameter portion 11E) corresponding to the joint part JPE has a substantially elliptical transverse sectional shape, and a second core shaft 30E corresponding to the joint part JPE has a substantially rectangular transverse sectional shape. The joint part JPA according to the sixth embodiment is formed by filling a gap between the small-diameter portion 11E and a proximal end portion of the second core shaft 30E adjacent to each other with the joining agent <NUM>. For the joining agent <NUM>, the metal solder or the adhesive described as examples in the first embodiment can be used. The joining agent <NUM> according to the sixth embodiment may be the same as or different from that in the first embodiment.

Also in the sixth embodiment as described above, the transverse sectional shape of the first core shaft 10E (<FIG>: small-diameter portion 11E) and the transverse sectional shape of the second core shaft 30E (<FIG>: second core shaft 30E) are different from each other on the joint part JPE, and therefore the same effect as the aforementioned effect in the first embodiment can be accomplished by treating a contact face between the first and second core shafts 10E and 30E adjacent to each other on the joint part JPE as a joining face L3 (<FIG>). Incidentally, the transverse sectional shape of the first core shaft 10E and the transverse sectional shape of the second core shaft 30E on the joint part JPE described as an example in the sixth embodiment are not limited to the substantially rectangular shape or the substantially elliptical shape, and can include, for example, various shapes such as a substantially circular shape, a polygonal shape, or a substantially circular shape or elliptical shape having a groove portion.

<FIG> is a partial sectional view illustrating a distal end side of a guide wire 1F according to the seventh embodiment. In the guide wire 1F according to the seventh embodiment, the first core shaft 10F includes a small-diameter portion 11F having a length in the axis line O direction (X-axis direction) longer than of the small-diameter portion <NUM> according to the first embodiment. The first core shaft 10F does not include the first decreasing-diameter portion <NUM>, and the first large-diameter portion <NUM> (<FIG>) is connected to a proximal end side of the small-diameter portion 11F. A joint part JPF between the first and second core shafts 10F and <NUM> is disposed on a distal end side of the small-diameter portion 11F. Incidentally, in the small-diameter portion 11F, only a part on the distal end side corresponding to the joint part JPF has a substantially rectangular transverse sectional shape illustrated in <FIG>, and a part on the proximal end side of the joint part JPF has a transverse sectional shape other than the substantially rectangular shape (e.g. a substantially circular shape).

In the seventh embodiment as described above, a part where the first core shaft 10F (small-diameter portion 11F) on the proximal end side of the joint part JPF is covered by the covering portion <NUM> corresponds to the third region R3 (<FIG>: third region R3). In addition, a part where the small-diameter portion 11F and the first large-diameter portion <NUM> of the first core shaft 10F are exposed from the covering portion <NUM> corresponds to the fourth region R4 (<FIG>: fourth region R4). The guide wire 1D according to the seventh embodiment also accomplishes the same effect as in the first embodiment.

<FIG> is a partial sectional view illustrating a distal end side of a guide wire <NUM> according to the eighth embodiment. The guide wire <NUM> according to the eighth embodiment includes a second core shaft <NUM> having a different shape from the second core shaft <NUM> according to the first embodiment. The second core shaft <NUM> has a small-diameter portion <NUM>, a decreasing-diameter portion <NUM>, and a large-diameter portion <NUM> in this order from the distal end side to the proximal end side. An outer diameter and a length of each portion can be arbitrarily determined.

The small-diameter portion <NUM> is disposed on the distal end side of the second core shaft <NUM>, and has a substantially cylindrical shape with an outer diameter equivalent to the smallest outer diameter of the second core shaft <NUM>. The distal end side of the small-diameter portion <NUM> is fixed to the coil body <NUM> and the covering portion <NUM> by the distal end-side fixation portion <NUM>. The decreasing-diameter portion <NUM> is disposed between the small-diameter portion <NUM> and the large-diameter portion <NUM>, and has a substantially truncated cone shape with an outer diameter decreasing from the proximal end side to the distal end side. The large-diameter portion <NUM> is disposed on the proximal end side of the second core shaft <NUM>, and has a substantially cylindrical shape with an outer diameter equivalent to the largest outer diameter of the second core shaft <NUM>. As illustrated in <FIG>, the proximal end side of the large-diameter portion <NUM> is joined to the small-diameter portion <NUM> on the distal end side of the first core shaft <NUM>. At least a part corresponding to a joint part JPG in the large-diameter portion <NUM> has a substantially elliptical transverse sectional shape with a major axis and a minor axis (as in <FIG>).

Also in this guide wire <NUM> according to the eighth embodiment, the same effect as in the first embodiment can be accomplished. Additionally, in the guide wire <NUM> according to the eighth embodiment, the second core shaft <NUM> positioned in the first region R1 includes the decreasing-diameter portion <NUM> decreasing in diameter toward the distal end side and the small-diameter portion <NUM> having the smallest outer diameter, and therefore the distal end portion of the guide wire <NUM> can be more easily shaped. Incidentally, the configuration of the second core shaft <NUM> according to the eighth embodiment can be variously modified. For example, when a configuration including a flat portion <NUM> having a flat transverse sectional shape is adopted instead of the small-diameter portion <NUM>, the flat portion <NUM> can be formed by pressing a distal end side of a substantially cylindrical material. Also, the transverse section of the large-diameter portion <NUM> can be formed into a substantially elliptical shape by presswork.

<FIG> is a partial sectional view illustrating a distal end side of a guide wire <NUM> according to the ninth embodiment. In the guide wire <NUM> according to the ninth embodiment, the first core shaft <NUM> and the second core shaft <NUM> are not directly joined to each other but are joined via the covering portion <NUM>. Specifically, the outer side face of the second core shaft <NUM> and the inner side face of the covering portion <NUM> are joined to each other at least on a part in the axis line O direction to form a joint part JP1. In addition, the outer side face of the first core shaft <NUM> (first decreasing-diameter portion <NUM>) and the inner side face of the covering portion <NUM> are joined to each other at least on a part in the axis line O direction to form a joint part JP2.

The covering portion <NUM> covers the first and second core shafts <NUM> and <NUM>, and is fixed to the distal end-side fixation portion <NUM>. Thus, the first core shaft <NUM> can be indirectly joined to the second core shaft <NUM> via the covering portion <NUM> by disposing the aforementioned joint part JP1 and joint part JP2. The guide wire <NUM> according to the ninth embodiment also accomplishes the same effect as in the first embodiment.

<FIG> is a partial sectional view illustrating a distal end side of a guide wire 1J according to the tenth embodiment. The guide wire 1J according to the tenth embodiment includes a resin body <NUM> instead of the coil body <NUM>. The resin body <NUM> is arranged so as to cover the outside of the covering portion <NUM> and the first core shaft <NUM> not covered by the covering portion <NUM> (exposed from the covering portion <NUM>). The guide wire 1J according to the tenth embodiment also accomplishes the same effect as in the first embodiment.

Note that the disclosed embodiments are not limited to the above embodiments, for example, the following modifications are also possible.

In the aforementioned first to tenth embodiments, the configurations of the guide wire <NUM>, 1A to 1J have been described as examples. However, the configuration of the guide wire can be variously changed. For example, the guide wire according to each of the embodiments has been explained as a medical appliance used for inserting a catheter into a blood vessel, but can be configured as a guide wire to be inserted into each organ in a human body, such as a lymphatic system, a biliary system, a urinary system, respiratory system, a digestive system, a secretory gland, and a genital organ. For example, the guide wire may be configured such that the second decreasing-diameter portion and the second large-diameter portion are absent, and the whole first core shaft is covered by the coil body. For example, the guide wire may be productized in a state that the distal end side is previously curved.

In the first to tenth embodiments, the configurations of the first and second core shafts <NUM>, 10E, 10F, <NUM>, 30E, and <NUM> have been described as examples. However, the configurations of the first and second core shafts can be variously modified. For example, the first core shaft may be configured so as not to have the first decreasing-diameter portion and the second decreasing-diameter portion and so as to have the same diameter throughout the axis line O. For example, in the joint part JP (<FIG>), the arrangements of the first and second core shafts in the Z-axis direction may be reversed. Also, on the joint part JP (<FIG>), the first and second core shafts may be adjacent to each other in the Y-axis direction. For example, the first core shaft may be composed of a plurality of core shaft members that are joined together. In this case, each core shaft member may be made of the same material or different materials.

In the first to tenth embodiments, the configuration of the coil body <NUM> has been described as an example. However, the configuration of the coil body can be variously changed. For example, the coil body may have a densely-wound structure without gaps between the adjacent wires, a coarsely-wound structure with gaps between the adjacent wires, or a mixed structure of the densely-wound structure and the coarsely-wound structure. In addition, the coil body may include a resin layer coated with e.g. a hydrophobic resin material, a hydrophilic resin material, or a mixture thereof. For example, a transverse sectional shape of the wire of the coil body is not necessarily the substantially circle shape.

The configurations of the guide wires <NUM>, 1A to 1J according to the first to tenth embodiments, and the configurations of the guide wires according to the modification examples <NUM> to <NUM> may be appropriately combined. For example, in the guide wire 1A according to the second embodiment (configuration in which the joint part JPAis disposed on the first decreasing-diameter portion), the transverse sectional shapes of the first core shaft (first decreasing-diameter portion) and second core shaft corresponding to the joint part may be different from each other. In addition, for the guide wire 1A according to the second embodiment, it is possible to adopt the configuration including the distal end region (the third embodiment), the configuration without the third region (the fourth embodiment), the configuration without the fourth region (the fifth embodiment), or the configuration including the resin body instead of the coil body (the tenth embodiment). In addition, for the guide wire <NUM> according to the ninth embodiment (configuration in which the first and second core shaft are indirectly joined to each other), it is possible to adopt the configuration including the distal end region (the third embodiment), the configuration without the third region (the fourth embodiment), the configuration without the fourth region (the fifth embodiment), or the configuration including the resin body instead of the coil body (the tenth embodiment).

Claim 1:
A guide wire (<NUM>,1A-1J) comprising:
a first core shaft (<NUM>, 10D, 10E, 10F) made of a superelastic material;
a second core shaft (<NUM>, 30E, <NUM>) made of a material more susceptible to plastic deformation than the superelastic material of the first core shaft (<NUM>, 10D, 10E, 10F) and having a proximal end side joined to a distal end side of the first core shaft (<NUM>, 10D, 10E, 10F) and having a distal end side extending beyond a distal end of the first core shaft (<NUM>, 10D, 10E, 10F) on a distal side of the guide wire; and
a covering portion (<NUM>, 40B, 40C, 40D) covering a joint part (JP) between the first core shaft (<NUM>, 10D, 10E, 10F) and the second core shaft (<NUM>, 30E, <NUM>) and at least a part of the second core shaft (<NUM>, 30E, <NUM>) that is on a distal end side of the joint part (JP), wherein
from a distal end side toward a proximal end side of the guide wire (<NUM>, 1A-1J),
a first region (R1) where the second core shaft (<NUM>, 30E, <NUM>) on the distal end side of the joint part (JP) is covered by the covering portion (<NUM>, 40B, 40C, 40D) , and
a second region (R2) adjacent to the first region, where the joint part (JP) is covered by the covering portion (<NUM>, 40B, 40C, 40D), are disposed, and
the first region is more susceptible to plastic deformation than the second region,
wherein the guide wire (<NUM>, 1A-1J) further comprises a coil body (<NUM>) having a substantially cylindrical shape formed by spirally winding a wire (<NUM>) around the first core shaft (<NUM>, 10D, 10E, the second core shaft (<NUM>, 30E, <NUM>; covering portion (<NUM>, 40B, 40C, 40D).