Guide wire

Abstract

To provide a guide wire to be easily inserted by facilitating bending of a tip part even in a tubular organ or the like which is bent or curved.SOLUTION: A guide wire 10 includes a core wire 20, a coil member 40, and a resin filling part 50. A tip part 23 of the core wire 20 includes a rigid change part 31 where rigidity is rapidly changed. The resin filling part 50 includes: a tip side filling part 51 where a part between a tip part side portion of the tip part 23 of the core wire 20 and a roughly wound portion 43 of the coil member 40 is filled with a first resin; and a proximal end side filling part 53 where a part between a proximal end side portion positioned on a proximal end side of the tip side portion in the tip part 23 of the core wire 20 and the roughly wound portion 43 of the coil member 40 is filled with a second resin having hardness higher than the hardness of the first resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a guide wire used when placing a catheter or the like at a predetermined position in a tubular organ of the human body such as a blood vessel, a bile duct, a pancreatic duct, a ureter, a trachea, or a body tissue such as a body cavity.

Background Art

[0002] For example, during hemodialysis, as shown in FIG. 8, an artery 1 and a vein 2 are anastomosed under the skin of the arm or the like to increase the amount of blood flowing through the vein, and a shunt is performed. The portion where the artery 1 and the vein 2 are anastomosed at this time is referred to as an "anastomosis portion 3".

[0003] By the passage of time or the like, the inner diameter of the above-described anastomosis portion 3 may become smaller or blocked. In addition, not only the anastomosis portion 3 but also a stenosis may occur in the blood vessels or the like around it. Therefore, the anastomosis portion 3 or the stenosis portion (hereinafter simply referred to as the "anastomosis portion or the like") has been expanded with a balloon catheter or an expanding device such as a stent has been placed in the anastomosis portion or the like for expansion.

[0004] In this case, as shown in FIG., for example, the guide wire 5 is inserted from the artery 1 side, and after its tip reaches the vein 2, a catheter containing a balloon catheter or a stent is moved through the guide wire 5, and the anastomosis portion or the like is expanded with a balloon catheter or a stent is placed in the anastomosis portion or the like for expansion. After expanding the anastomosis portion or the like, the balloon catheter is removed from the body, and the stent is left in place after expanding the anastomosis portion or the like.

[0005] As an example of the guide wire described above, Patent Document 1 below describes one comprising a core shaft, a first coil body wound around the core shaft, and a second coil body provided inside the first coil body. The first coil body has a loosely wound portion where each strand is spaced apart, and a tightly wound portion provided adjacent to the base end of the loosely wound portion where each strand is in contact. A joint is provided at the boundary between the loosely wound portion and the tightly wound portion, where the first coil body and the second coil body are joined without being joined to the core shaft. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6008451 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, as shown in Figure 8, the anastomosis portion 3 is bifurcated due to the anastomosis of the vein 2 to the artery 1. When the anastomosis portion 3 has this shape, the direction of advancement of the guidewire 5 in the artery 1 (see arrow F1) and the direction of advancement of the guidewire 5 in the vein 2 (see arrow F2) are opposite. Therefore, it is necessary to change the direction of the leading edge 5a of the guidewire 5 near the anastomosis portion 3. For this reason, the tip of the guidewire 5 is required to be flexible.

[0008] In this regard, in the case of the guidewire described in Patent Document 1, the first coil body has a joint at the boundary between the loosely wound portion and the tightly wound portion, and the rigidity of the first coil body changes through this joint, so the first coil body is easily bent at the boundary portion, and the tip of the guidewire is easily deformed. Furthermore, the ease of bending of the guidewire tip is required not only when inserting the guidewire into anastomosis portions as described above, but also when inserting the guidewire into predetermined locations in tubular organs such as blood vessels or curved portions of body cavities.

[0009] However, as with the guidewire described in Patent Document 1, improvements to the first coil body alone are insufficient to ensure the flexibility of the tip of the entire guidewire. As shown in Figure 8, it can be difficult to reach the vein 2 with the guidewire 5, and it can also be difficult to reach specific locations in curved parts of tubular organs such as blood vessels or body cavities.

[0010] Therefore, the object of the present invention is to provide a guide wire whose tip can be easily bent, allowing for easy insertion into tubular organs, body cavities, etc., that are bent or curved. [Means for solving the problem]

[0011] To achieve the above objective, one guide wire according to the present invention comprises a core wire having a base portion and a tip portion having a smaller diameter than the base portion, a coil member attached to the outer circumference of the tip portion of the core wire, and a resin-filled portion between the tip portion of the core wire and the coil member, wherein the tip portion of the core wire has a stiffness change portion in which the stiffness changes abruptly in the axial direction, and the bending strength of the tip portion in the axial direction and the bending strength of the base portion in the axial direction are different, with the stiffness change portion as the boundary, the coil member has loosely wound portions formed by winding wire at predetermined intervals along its entire length, and the resin-filled portion comprises a tip-side filling portion in which a first resin is filled between the tip portion of the tip portion of the core wire and the loosely wound portion of the coil member, and a base-side filling portion in which a second resin having a hardness higher than the hardness of the first resin is filled between the base portion of the tip portion of the core wire located closer to the base than the tip portion and the loosely wound portion of the coil member.

[0012] Furthermore, another guide wire according to the present invention comprises a core wire having a base portion and a tip portion having a smaller diameter than the base portion, a coil member attached to the outer circumference of the tip portion of the core wire, and a resin-filled portion between the tip portion of the core wire and the coil member, wherein the tip portion of the core wire has a rigidity change portion in which the rigidity changes abruptly in the axial direction, and the bending strength of the tip portion in the axial direction and the bending strength of the base portion in the axial direction are different, with the rigidity change portion as the boundary, and the coil member has a loosely wound portion in which the wire is wound at predetermined intervals and a tightly wound portion in which the wire is wound without intervals, and the loosely wound portion The core wire is positioned at the tip end, the tightly wound portion is positioned at the base end, and the resin-filled portion has a tip-side filling portion in which a first resin is filled between the tip-side portion of the core wire and the loosely wound portion of the coil member, and also has a base-side filling portion in which a second resin having a hardness higher than the hardness of the first resin is filled between the base-side portion of the core wire, which is located closer to the base end than the tip-side portion, and the tightly wound portion of the coil member, or there is a gap between the base-side portion of the core wire, which is located closer to the base end than the tip-side portion, and the tightly wound portion of the coil member. [Effects of the Invention]

[0013] According to one of the guide wires of the present invention, the tip of the core wire can produce a change in bending strength due to a rigidity change section, and the resin-filled section can produce a change in hardness at the boundary between the tip-side filled section and the base-side filled section. As a result, the tip of the guide wire can be made easier to bend, starting from both the section that produces a change in bending strength and the section that produces a change in hardness, and the guide wire can be easily inserted into bent or curved tubular organs, body cavities, etc.

[0014] Also, according to another aspect of the guide wire of the present invention, at the tip of the core wire, a change in bending strength can be caused by the rigidity change portion, and in the resin filling portion, a change in hardness can be caused by the boundary portion between the tip side filling portion and the base end side filling portion or the boundary portion between the tip side filling portion and the void. As a result, starting from both the portion causing the change in bending strength and the portion causing the change in hardness, the tip of the guide wire can be made easier to bend, and the guide wire can be easily inserted into a tubular organ or body cavity that is bent or curved.

Brief Description of the Drawings

[0015] [Figure 1] The first embodiment of the guide wire according to the present invention is shown, and it is a cross-sectional view thereof. [Figure 2] It is a cross-sectional view of the state where the tip of the guide wire is bent. [Figure 3] The usage method of the guide wire is shown, (a) is an explanatory diagram of the first step, (b) is an explanatory diagram of the second step, and (c) is an explanatory diagram of the third step. [Figure 4] The usage method of the guide wire is shown, (a) is an explanatory diagram of the fourth step, (b) is an explanatory diagram of the fifth step, and (c) is an explanatory diagram of the sixth step. [Figure 5] The second embodiment of the guide wire according to the present invention is shown, and it is a cross-sectional view thereof. [Figure 6] The third embodiment of the guide wire according to the present invention is shown, (a) is a cross-sectional view thereof, (b) is a cross-sectional view in a direction orthogonal to (a), and (c) is a cross-sectional view taken along the A-A line of sight of (a). [Figure 7] The fourth embodiment of the guide wire according to the present invention is shown, and it is a cross-sectional view thereof. [Figure 8] It is an explanatory diagram showing the usage method of a conventional guide wire.

Modes for Carrying Out the Invention

[0016] (First Embodiment of the Guide Wire) Hereinafter, with reference to the drawings, an embodiment of the guide wire according to the present invention will be described. FIGS. 1 to 4 show a first embodiment of the guide wire according to the present invention.

[0017] As shown in FIG. 1, the guide wire 10 of this embodiment includes a core wire 20 having a base portion 21 and a tip portion 23 with a diameter smaller than that of the base portion 21, a coil member 40 attached to the outer periphery of the tip portion 23 of the core wire 20, and a resin filling portion 50 filled with resin between the tip portion 23 of the core wire 20 and the coil member 40.

[0018] As shown in FIG. 1, in the axial direction of the guide wire 10, the portion where the tip portion 23 of the core wire 20, the coil member 40, and the resin filling portion 50 are located is defined as the tip portion 11 of the guide wire 10.

[0019] First, the core wire 20 will be described.

[0020] The base portion 21 of the core wire 20 in this embodiment is a round wire having a circular cross-section and extends at a constant outer diameter for a predetermined length. From the tip of this base portion 21, a first tapered portion 25 is provided which extends at a predetermined angle so as to gradually decrease in diameter toward the foremost tip 23a of the core wire 20.

[0021] Also, from the tip portion of the first tapered portion 25, a second tapered portion 27 is provided which extends at an angle different from that of the first tapered portion 25 so as to gradually decrease in diameter toward the foremost tip 23a of the core wire 20. The angle θ2 of the second tapered portion 27 with respect to the axis C of the core wire 20 is larger than the angle θ1 of the first tapered portion 25 with respect to the axis C of the core wire 20, and the second tapered portion 27 is inclined at a steeper angle than the first tapered portion 25. Further, a reduced diameter portion 29 extends linearly from the tip portion 27a of the second tapered portion 27 with a constant outer diameter.

[0022] In the case of this embodiment, the first tapered portion 25, the second tapered portion 27, and the reduced diameter portion 29 form the tip portion 23 of the core wire 20.

[0023] Furthermore, the very tip 23a of the tip portion 23 of the core wire 20 is the distal end, furthest from the guide wire operator's hand, while the very base of the base portion 21 is the proximal end, closest to the guide wire operator's hand.

[0024] Furthermore, in the core wire 20 described above and each component described below (coil component, resin-filled part, etc.), "tip," "tip," and "tip side" refer to the distal end, distal end, and distal end side furthest from the guide wire operator's hand, while "base end," "base end," and "base side" refer to the proximal end, proximal end, and proximal end side closest to the guide wire operator's hand.

[0025] Furthermore, the tip portion 23 of the core wire 20 has a stiffness change portion 31 in which the stiffness changes abruptly in the axial direction, and the bending strength of the tip portion in the axial direction (hereinafter also simply referred to as the "axial tip portion") and the base portion in the axial direction (hereinafter also simply referred to as the "axial base portion") are formed to be different, with the stiffness change portion 31 as the boundary.

[0026] Furthermore, the tip portion 23 of the core wire 20 is formed such that its outer diameter changes very significantly at the boundary portion (connecting portion) between the tip portion 27a of the second tapered portion 27 and the base portion 29a of the small diameter portion 29. As a result, the rigidity of the tip portion 23 of the core wire 20 changes abruptly at the boundary portion, and this boundary portion constitutes a rigidity change portion 31. The rigidity change portion 31 can also be called a "rigidity gap" in the sense that the rigidity of the tip portion 23 of the core wire 20 changes abruptly.

[0027] Furthermore, in this embodiment, the small diameter portion 29 constitutes the "axial tip portion" described above, and the tip side of the second tapered portion 27 and the first tapered portion 25 (the end side connected to the second tapered portion 27) and the portion to which the coil member 40 is externally mounted constitutes the "axial base portion" described above.

[0028] In this embodiment, the tip portion 23 of the core wire 20 is formed such that the bending strength of the axial base portion is greater than that of the axial tip portion, with the rigidity change portion 31 as the boundary.

[0029] In this embodiment, the bending strength of the axial tip portion of the tip 23 of the core wire 20 is smaller than that of the axial base portion of the tip 23 of the core wire 20 throughout its entire radial range. That is, unlike the axial tip portion (forged portion 38) of the tip 23 of the core wire 20 of the guide wire 10B shown in Figure 6, which will be described later, which has a direction in which it is easier to bend (the bending ease has directionality), in this embodiment, there is no particular direction in which the axial tip portion of the tip 23 of the core wire 20 is easier to bend (the bending ease does not have directionality).

[0030] Furthermore, in this invention, "rigidity" refers to "bending rigidity." This bending rigidity is calculated by multiplying Young's modulus by the second moment of area.

[0031] In this embodiment, the core wire 20 is a round wire having a solid circular cross-section. If we assume that the outer diameter at the tip portion 27a of the second tapered portion 27 is D1, then the second moment of area is πD1. 4 / 64(mm 4 ) And if the outer diameter at the base end portion 29a of the narrow diameter portion 29 is D2, then the second moment of area is πD2 4 / 64(mm 4 ) For example, if D1 is 2 mm, the second moment of area is 0.785 mm 4 Therefore, if D2 is 1.5 mm, the second moment of area is 0.249 mm. 4 As a result, the bending stiffness changes abruptly at the stiffness change portion 31, which is the boundary portion between the tip portion 27a of the second tapered portion 27 and the base portion 29a of the narrow diameter portion 29.

[0032] Furthermore, the term "rigidity change section" in this invention can also be defined as follows. That is, in the case of a configuration in which the outer diameter of the tip 23 of the core wire 20 changes, such as the guide wire 10 of the first embodiment shown in Figure 1, the guide wire 10A of the second embodiment shown in Figure 5, and the guide wire 10C of the fourth embodiment shown in Figure 7, the "rigidity change section" refers to a part that becomes a recess or corner when the tip of the core wire is viewed from the radially outward direction, and where bending stress is concentrated when bending stress is applied to the tip of the core wire. As a result, when bending stress is applied to the tip of the core wire, the tip of the core wire is configured to bend starting from the rigidity change section.

[0033] In other words, the boundary between the tip portion 27a of the second tapered portion 27 and the base portion 29a of the narrow-diameter portion 29 forms a recess or corner when the tip portion 23 of the core wire 20 is viewed from the radially outward direction (see arrow F3 in the partially enlarged view of Figure 1), and also forms a rigidity change portion 31 because it is a place where bending stress is concentrated when bending stress is applied to the tip portion 23 of the core wire 20. When bending stress is applied to the tip portion 23 of the core wire 20, the tip portion 23 of the core wire 20 bends starting from the rigidity change portion 31, as shown in Figure 2.

[0034] On the other hand, the boundary between the tip portion of the first tapered portion 25 and the base portion of the second tapered portion 27 becomes a convex or angular portion when the tip portion 23 of the core wire 20 is viewed radially outward (see arrow F4 in the partially enlarged view of Figure 1), and therefore does not constitute a "rigidity change portion" in the present invention.

[0035] Furthermore, if there are multiple stiffness-changing sections as described above at the tip of the core wire, the section with the largest stiffness change rate among them becomes the "stiffness-changing section" in this invention.

[0036] Furthermore, in the case of a configuration in which the degree of processing of the tip portion 23 of the core wire 20 changes, such as the guide wire 10B of the third embodiment shown in Figure 6, the "rigidity change portion" refers to the boundary portion between the portion with a high processing rate and the portion with a low processing rate at the tip portion 23 of the core wire 20.

[0037] The core wire 20 can be, for example, a superelastic alloy such as a Ni-Ti alloy, a Ni-Ti-X (X=Fe, Cu, V, Co, Cr, Mn, Nb, etc.) alloy, or a Cu-Zn-X (X=Al, Fe, etc.) alloy, or stainless steel, piano wire, etc. Alternatively, an X-ray opaque metal consisting of W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, and alloys thereof can be used. Among the above, it is preferable to use Ni-Ti engagement metal, Ni-Ti-X alloy, or stainless steel.

[0038] Next, we will describe the coil member 40 attached to the outer circumference of the tip portion 23 of the core wire 20.

[0039] In this embodiment, the coil member 40 has loosely wound portions 43 formed along its entire length by winding a circular wire 41 of a constant outer diameter at predetermined intervals.

[0040] Furthermore, the inner and outer diameters of the coil member 40 are formed to be constant from the base to the tip. Moreover, the inner diameter of the coil member 40 is formed to be larger than the outer diameter of the tip portion of the first tapered portion 25, the outer diameter of the second tapered portion 27, and the outer diameter of the narrow portion 29 of the tip portion 23 of the core wire 20. Therefore, when the coil member 40 is placed on the outer circumference of the tip portion 23 of the core wire 20, a predetermined gap is formed between the inner circumference of the coil member 40 and the outer circumference of the aforementioned portions of the tip portion 23 of the core wire 20 (the tip portion of the first tapered portion 25, the second tapered portion 27, and the narrow portion 29).

[0041] Furthermore, with the coil member 40 positioned on the outer circumference of the tip portion 23 of the core wire 20, its base end is fixed to a predetermined location on the tip portion of the first tapered portion 25 via a fixing portion 33. In addition, with the coil member 40 positioned on the outer circumference of the tip portion 23 of the core wire 20, its tip end is fixed to the tip of the narrow-diameter portion 29 (the very tip 23a of the tip portion 23 of the core wire 20) via a fixing portion 35. In this way, the base end and tip end of the coil member 40 are fixed to the tip portion 23 of the core wire 20 via fixing portions 33 and 35, so that the coil member 40 is attached to the outer circumference of the tip portion 23 of the core wire 20.

[0042] The wire 41 forming the coil member 40 can be, for example, a superelastic alloy such as a Ni-Ti alloy, a Ni-Ti-X (X=Fe, Cu, V, Co, Cr, Mn, Nb, etc.) alloy, or a Cu-Zn-X (X=Al, Fe, etc.) alloy, or stainless steel, piano wire, etc. Alternatively, an X-ray opaque metal consisting of W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, and alloys thereof can be used. Among the above, it is preferable to use Ni-Ti engagement metal, Ni-Ti-X alloy, or stainless steel.

[0043] Furthermore, for the fixing parts 33 and 35, for example, wax materials such as Sn or Ag wax, UV-curing acrylate resin, silicone adhesive, modified silicone adhesive, epoxy resin adhesive, acrylate adhesive, urethane resin adhesive, etc. can be used.

[0044] Next, we will describe the resin-filled portion 50, which is formed by filling the space between the tip portion 23 of the core wire 20 and the coil member 40 with resin.

[0045] The resin-filled portion 50 has a tip-side filling portion 51 in which a first resin is filled between the tip-side portion of the tip portion 23 of the core wire 20 and the loosely wound portion 43 of the coil member 40, and a base-side filling portion 53 in which a second resin having a higher hardness than the first resin is filled between the base-side portion of the tip portion 23 of the core wire 20, which is located closer to the base end than the tip-side portion, and the loosely wound portion 43 of the coil member 40.

[0046] In this embodiment, the tip-side filling portion 51 and the base-side filling portion 53 fill the entire gap between the outer circumference of the tip portion 23 of the core wire 20 and the inner circumference of the coil member 40, and also fit between the wires 41, 41 of the coil member 40.

[0047] As described above, the hardness of the second resin filled in the base-side filling portion 53 is higher than that of the first resin filled in the tip-side filling portion 51. Since the hardness differs between the tip-side filling portion 51 and the base-side filling portion 53, a clear change in hardness is observed at the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 (i.e., the portion where the base end of the tip-side filling portion 51 and the tip of the base-side filling portion 53 face each other). This boundary portion 55 can also be called a "hardness gap" in the sense that the hardness of the resin-filled portion 50 changes.

[0048] As a result, as shown in Figure 2, when bending stress is applied to the tip 11 of the guide wire 10, the tip 11 of the guide wire 10 bends not only from the stiffness change portion 31 (stiffness gap) of the tip 23 of the core wire 20, but also from the boundary portion 55 (hardness gap) between the tip-side filling portion 51 and the base-side filling portion 53 of the resin-filled portion 50.

[0049] Furthermore, in this embodiment, the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 is positioned to coincide with the axial direction of the core wire 20 with respect to the rigidity change portion 31 provided at the tip portion 23 of the core wire 20.

[0050] The first resin constituting the tip-side filling portion 51 and the second resin constituting the base-side filling portion 53 can be, for example, polyurethane, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, UV-curing resins such as acrylate resins, resins used in adhesives (acrylate resins, urethane-based, epoxy-based, silicone-based), polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), and other fluorine-based resins. However, the hardness of the second resin must be higher than that of the first resin. In this embodiment, the first resin is polyurethane, and the second resin is a UV-curing acrylate resin.

[0051] Furthermore, the materials for the first resin and the second resin are preferably materials whose hardness, as measured by a durometer as specified in JIS K 6253, has a difference of 10 or more, and more preferably a difference of 50 or more.

[0052] Furthermore, at least the outer circumference of the coil member 40 is covered with a resin cover 60. As shown in Figure 1, in this embodiment, the resin cover 60 covers the entire outer circumference of the coil member 40 and the outer circumference of the core wire 20.

[0053] Furthermore, the inner surface of the resin cover 60 is joined to the tip-side filling portion 51 and the base-side filling portion 53. In this embodiment, the inner surface of the resin cover 60 is joined to the outer circumference of the coil member 40 via adhesive, and as shown in the partially enlarged view of Figure 1, it is also joined to the tip-side filling portion 51 and the base-side filling portion 53, which are inserted between the wires 41, 41 forming the coil member 40, via adhesive.

[0054] Furthermore, in this embodiment, the outer circumference of the resin cover 60 is further coated with a hydrophilic resin film 70. This hydrophilic resin film 70 can be made of, for example, a hydrophilic resin such as polyvinylpyrrolidone, polyethylene glycol, or methyl vinyl ether maleic anhydride copolymer.

[0055] As shown in Figure 1, the tip of the resin cover 60 (the part covering the fixing portion 35 located at the very tip 23a of the core wire 20) and the tip of the hydrophilic resin film 70 are considered to be the very tip 13 of the guide wire 10.

[0056] (modified version) The shape, structure, material, and layout of the core wire, coil member, resin-filled section, etc., that constitute the guide wire described above are not limited to the above-described embodiments.

[0057] In this embodiment, the tip portion 23 of the core wire 20 has a configuration having two tapered portions 25, 27 that gradually decrease in diameter toward the outermost tip 23a of the core wire 20 and a thin portion 29 of a constant diameter. However, the tip portion of the core wire may also be, for example, (1) a combination of one or more tapered portions and a thin portion, (2) a combination of one or more tapered portions, or (3) a shape having a large diameter portion extending of a constant diameter and length, and a small diameter portion that is smaller in diameter than the outer diameter portion and extends of a constant diameter and length, such that the outer circumference of the tip portion of the core wire changes in a stepped manner. Any shape or structure having a rigidity change portion is acceptable.

[0058] Furthermore, in this embodiment, the stiffness change portion 31 is provided by significantly changing the outer diameter of the tip portion 23 of the core wire 20 with the stiffness change portion 31 as the boundary. However, the stiffness change portion may also be provided, for example, by performing forging or the like on the axial tip portion or the axial base portion of the tip portion of the core wire (this will be explained in the third embodiment shown in Figure 6).

[0059] Furthermore, in this embodiment, the tip portion 23 of the core wire 20 is formed such that the bending strength of the axial base portion is greater than that of the axial tip portion, with the rigidity change portion 31 as the boundary. However, the tip portion of the core wire may also be formed such that the bending strength of the axial tip portion is greater than that of the axial base portion, with the rigidity change portion as the boundary.

[0060] Furthermore, in this embodiment, the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 is positioned to coincide with the axial direction of the core wire 20 with respect to the rigidity change portion 31 of the tip portion 23 of the core wire 20. However, the boundary portion between the tip-side filling portion and the base-side filling portion may be offset by, for example, 1 to 5 mm toward the tip side or base end side of the core wire with respect to the rigidity change portion.

[0061] Furthermore, although the coil member 40 in this embodiment has a loosely wound portion 43 formed along its entire length, the coil member may also have, for example, a loosely wound portion and a tightly wound portion (this will be explained in the fourth embodiment shown in Figure 7).

[0062] Furthermore, although the resin-filled portion 50 of this embodiment has a tip-side filling portion 51 and a base-side filling portion 53, the resin-filled portion may also be configured such that, for example, the tip-side filling portion is provided only in the tip-side portion of the core wire, and the base-side portion of the core wire is left as a void (this will be described in detail in the description of the fourth embodiment shown in Figure 7).

[0063] Furthermore, although the resin cover 60 in this embodiment covers not only the coil member 40 but also the entire outer circumference of the core wire 20, the resin cover only needs to be capable of covering at least the coil member.

[0064] Furthermore, in this embodiment, the coil member 40 is fixed to the core wire 20 at its base end and tip end via fixing portions 33 and 35. However, the coil member does not necessarily need to be fixed to the core wire at its base end and tip end via fixing portions.

[0065] Furthermore, in this embodiment, the coil member 40 extends with approximately the same length toward the base end and tip end, with respect to the rigidity change portion 31 of the core wire 20 (see Figure 1). However, for example, the base end of the coil portion may be extended longer than shown in Figure 1 toward the base end of the first tapered portion 25 of the tip portion 23 of the core wire 20, and the length of the coil member is not particularly limited.

[0066] Furthermore, in this embodiment, a coil member 40 wound with wire made of the same material is used, but coil members made of two or more materials may be used in combination. For example, a coil member made of Pt wire may be placed on the outer circumference of the portion of the core wire 20 that is axially closer to the tip end than the stiffness change portion 31, and a coil member made of W wire may be placed on the outer circumference of the portion of the core wire 20 that is axially closer to the base end than the stiffness change portion 31. In this case, the two coil members can be connected in the axial direction by appropriately intertwining the wires of both coil members at the boundary between the base end of the Pt coil member and the tip end of the W coil member.

[0067] Furthermore, the material of the resin cover 60 is not particularly limited, but the material of the resin cover may be the same as the first resin constituting the tip-side filling portion 51 or the second resin constituting the base-side filling portion 53.

[0068] (Effects and Benefits) Next, we will explain how to use the guide wire of the present invention, which has the above structure.

[0069] As shown in Figures 3 and 4, the guidewire 10 of this embodiment is used, for example, when an anastomosis is formed by connecting an artery 1 and a vein 2 subcutaneously in the arm to increase the amount of blood flowing into a vein during hemodialysis. In this embodiment, a dilator (balloon catheter 7) is placed in the anastomosis portion 3 to expand the anastomosis portion 3 between artery 1 and vein 2. The anastomosis portion 3 between artery 1 and vein 2 has a bifurcated shape.

[0070] Furthermore, the guidewire 10 can also be used to position catheters or place stents in predetermined locations in human tissues such as blood vessels other than those subcutaneous in the arm, various tubular organs such as bile ducts, pancreatic ducts, ureters, and tracheas, or body cavities, and the location of use of the guidewire 10 is not particularly limited.

[0071] When using the guidewire 10, the guidewire 10 is inserted into the artery 1 from its tip end 11 and pushed in (see arrow F1 in Figure 3(a)). When the leading edge 13 of the guidewire 10 passes through the anastomosis portion 3 and contacts a predetermined location on the inner wall of the artery 1, the tip 11 of the guidewire 10 bends, as shown in Figure 2, starting from the rigidity change portion 31 of the tip 23 of the core wire 20 and the boundary portion 55 between the tip-side filling portion 51 and the proximal-side filling portion 53 of the resin-filled portion 50. Also, as shown in Figure 3(a), the leading edge 13 of the guidewire 10 contacts the inner wall of the anastomosis portion 3.

[0072] Furthermore, as the guidewire 10 is pushed in, as shown in Figure 3(b), the guidewire 10 bends to form a roughly U-shape at a predetermined point in the axial direction. At this time, the leading edge 13 of the guidewire 10 moves away from the inner wall of the anastomosis portion 3 and no longer faces the vein 2. Therefore, the proximal end of the guidewire 10 is rotated, and as shown in Figure 3(c), the tip 11 of the guidewire 10 is rotated so that its leading edge 13 faces the vein 2.

[0073] In this state, as the guidewire 10 is pushed in, the tip 11 of the guidewire 10 is inserted into the lumen of vein 2, as shown in Figure 4(a). The guidewire 10 is pushed in further until the very tip 13 of the guidewire 10 reaches the predetermined position in vein 2, as shown in Figure 4(b). Then, the balloon catheter 7 is inserted while being guided by the guidewire 10, and after the balloon catheter 7 is placed in the anastomosis 3, the guidewire 10 is withdrawn from the balloon catheter 7.

[0074] In the above state, the inner diameter of the anastomosis portion 3 can be expanded by inflating the balloon catheter 7 with saline solution or the like, as shown in Figure 4(c).

[0075] Furthermore, in this guide wire 10, the tip portion 23 of the core wire 20 is formed such that the bending strength differs between the axial tip portion and the axial base portion, with the rigidity change portion 31, which is the boundary, where the rigidity changes abruptly. Therefore, the tip portion 23 of the core wire 20 can clearly produce a change in bending strength with the rigidity change portion 31 as the boundary.

[0076] Furthermore, since the resin-filled portion 50 has a tip-side filled portion 51 filled with a first resin and a base-side filled portion 53 filled with a second resin having a harder hardness than the first resin, a clear change in hardness can be made using the boundary portion 55 between the tip-side filled portion 51 and the base-side filled portion 53 as the boundary.

[0077] Therefore, when inserting the guidewire 10 into a curved tubular organ or body cavity, the tip 11 of the guidewire 10 can be easily bent starting from both the rigidity change portion 31 (rigidity gap) where the bending strength of the tip 23 of the core wire changes, and the boundary portion 55 (hardness gap) where the hardness of the resin-filled portion 50 changes (see Figure 3(a)). As a result, the guidewire 10 can be easily inserted into bent or curved tubular organs or body cavities. In addition, the tip 11 of the guidewire 10 can be easily bent according to the intention of the guidewire operator.

[0078] Furthermore, in this embodiment, the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 is positioned to coincide with the axial direction of the core wire 20 with respect to the rigidity change portion 31 provided at the tip portion 23 of the core wire 20.

[0079] According to the above embodiment, the stiffness-changing portion 31 at the tip 23 of the core wire 20, where the bending strength changes, and the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 at the resin-filled portion 50, where the hardness changes, can be made to coincide in the axial direction. This makes the tip 11 of the guide wire 10 easier to bend, allowing the guide wire 10 to be inserted more easily into bent or curved tubular organs, body cavities, etc.

[0080] Furthermore, in this embodiment, at least the outer circumference of the coil member 40 is covered with a resin cover 60, and the inner surface of the resin cover 60 is joined to the tip-side filling portion 51 and the base-side filling portion 53 (see partially enlarged view of Figure 1).

[0081] According to the above embodiment, since the inner surface of the resin cover 60 is joined to the tip-side filling portion 51 and the base-side filling portion 53, it is possible to make it difficult for the resin cover 60 to shift position relative to the coil member 40. That is, since the coil member 40 is sandwiched between the two filling portions 51 and 53 that are filled inside the coil member 40 and the resin cover 60 that covers the outer circumference of the coil member 40, it becomes difficult for the resin cover 60 to shift position relative to the coil member 40.

[0082] Furthermore, even if irregularities occur on the outer surface of the resin-filled portion 50 due to changes in the shrinkage rate between the tip-side filling portion 51 and the base-side filling portion 53, such irregularities can be covered by the resin cover 60.

[0083] Furthermore, the properties of the materials of the tip-side filling portion 51 and the base-side filling portion 53 may make it difficult to coat the outer circumference of the coil member 40 and the resin filling portion 50 with a hydrophilic resin film 70 or the like. Even in such cases, the hydrophilic resin film 70 or the like can be coated onto the resin cover 60 covering the outer circumference of the coil member 40, allowing for free selection of materials for the tip-side filling portion 51 and the base-side filling portion 53.

[0084] (Second embodiment of the guide wire) Figure 5 shows a second embodiment of the guide wire according to the present invention. Parts substantially identical to those in the previous embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0085] As shown in Figure 5, the guide wire 10A of this second embodiment differs from the first embodiment in the manner in which the coil member 40 is attached to the tip portion 23 of the core wire 20. Specifically, the base end and tip end of the coil member 40 are fixed to the tip portion 23 of the core wire 20 via fixing portions 33 and 35, and the coil member 40 is also fixed to the stiffness change portion 31 via a fixing portion 37 located on the stiffness change portion 31 of the tip portion 23 of the core wire 20.

[0086] Furthermore, the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 of the resin-filled portion 50 is positioned to coincide with the rigidity change portion 31 and the fixing portion 37 in the axial direction of the core wire 20.

[0087] Furthermore, in the guide wire 10A of this embodiment, the change in bending strength due to the rigidity change portion 31 at the tip portion 23 of the core wire 20, and the change in hardness at the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 in the resin-filled portion 50, are further clarified (emphasized) by the fixing portion 37, making the tip portion 23 of the guide wire 10A even easier to bend, and allowing the guide wire 10A to be inserted even more easily into bent or curved tubular organs, body cavities, etc.

[0088] (Third embodiment of the guide wire) Figure 6 shows a third embodiment of the guide wire according to the present invention. Parts substantially identical to those in the previous embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0089] As shown in Figure 6, unlike the guide wire 10 of the first embodiment, the guide wire 10A of the second embodiment, and the guide wire 10C of the fourth embodiment, the guide wire 10B of this third embodiment has a rigidity change portion 31 provided by forging the axial tip portion 23 of the core wire 20.

[0090] In other words, as shown in Figure 6(a), the forged portion 38 is provided by forging only on the axial tip end portion of the tip portion 23 of the core wire 20. The axial base end portion of the tip portion 23 of the core wire 20 is not forged.

[0091] Furthermore, the forged portion 38 becomes thinner with respect to the axial base end portion of the tip portion 23 of the core wire 20 (see Figure 6(b)) and has a long plate shape with a flat surface (Figure 6(a)) as a result of the forging process.

[0092] Furthermore, the axial base end portion 38a of the forged portion 38 is connected to the tip portion of the first tapered portion 25. In addition, both sides of the base end portion 38a of the forged portion 38 have a tapered shape that gradually narrows when the cross-section of the core wire 20 is viewed from the side, as shown in Figure 6(a), and a tapered shape that gradually widens when the cross-section of the core wire 20 is viewed from the planar direction (when viewed from a direction perpendicular to Figure 6(a)), as shown in Figure 6(b).

[0093] In this embodiment, the forged portion 38 forms the "axial tip side portion" of the tip portion 23 of the core wire 20, and the tip side of the first tapered portion 25, where the coil member 40 is attached, forms the "axial base end portion" of the tip portion 23 of the core wire 20.

[0094] Furthermore, by applying a forging process 38 to the axial tip end portion of the tip portion 23 of the core wire 20, the processing rate at the axial tip end portion of the tip portion 23 of the core wire 20 becomes greater than the processing rate at the axial base end portion, resulting in a higher hardness at the axial tip end portion than at the axial base end portion.

[0095] In other words, the boundary between the base end portion 38a of the forged portion 38, which is the part of the core wire 20 tip 23 with a high degree of processing, and the tip portion of the first tapered portion 25, which is the part with a low degree of processing, forms a rigidity change portion 31. As a result, the bending strength of the tip portion 23 of the core wire 20 differs between the axial tip portion and the axial base portion, with the rigidity change portion 31 as the boundary.

[0096] In this embodiment, the forged portion 38 provided on the axial end side of the tip portion 23 of the core wire 20 is flat, so as shown by arrow F3 in Figure 6(b), it is easy to bend in the direction perpendicular to the surface direction, while it is difficult to bend in the direction shown by arrow F4 in Figure 6(a) (the width direction of the flat forged portion 38) (it can be said that there is a directionality to how easily it bends).

[0097] Therefore, in the case of the guide wire 10B of this embodiment, as shown at least in Figure 6(b), when the cross-section of the core wire 20 is viewed from the planar direction (or from the thickness direction of the forged portion 38), the tip portion 23 of the core wire 20 has a greater bending strength at the axial base end portion than at the axial tip end portion, with the rigidity change portion 31 as the boundary.

[0098] Furthermore, in this embodiment of the guide wire 10B, as in the first embodiment, the rigidity change portion 31 at the tip portion 23 of the core wire 20 and the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 of the resin-filled portion 50 are both made easily bendable, allowing the guide wire 10A to be easily inserted into bent or curved tubular organs, body cavities, etc.

[0099] (Fourth embodiment of the guide wire) Figure 7 shows a fourth embodiment of the guide wire according to the present invention. Parts substantially identical to those in the previous embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0100] As shown in Figure 7, the guide wire 10C of this fourth embodiment differs from that of the first to third embodiments in the structure of the coil member.

[0101] In other words, the coil member 40C in this embodiment has a loosely wound portion 43 formed by winding the wire 41 at predetermined intervals and a tightly wound portion 45 formed by winding the wire 41 without any intervals, with the loosely wound portion 43 positioned towards the tip and the tightly wound portion 45 positioned towards the base.

[0102] Furthermore, both the loosely wound portion 43 and the tightly wound portion 45 are formed by winding a circular wire 41 of a constant outer diameter with or without gaps between them, and the inner and outer diameters of the loosely wound portion 43 and the tightly wound portion 45 are formed to be constant from the base end to the tip.

[0103] The tightly wound portion 45 is positioned on the outer circumference of the tip portion 23 of the core wire 20, with its base end fixed to the axial middle portion of the first tapered portion 25 of the tip portion 23 of the core wire 20 via a fixing portion 33. On the other hand, the loosely wound portion 43 is positioned on the outer circumference of the tip portion 23 of the core wire 20, with its base end in contact with the tip of the tightly wound portion 45, and its tip end fixed to the tip of the narrow diameter portion 29 of the tip portion 23 of the core wire 20 via a fixing portion 35.

[0104] In this way, the coil member 40C is attached to the outer circumference of the tip portion 23 of the core wire 20 with the loosely wound portion 43 positioned towards the tip and the tightly wound portion 45 towards the base.

[0105] Furthermore, the resin-filled section 50 has a tip-side filling section 51 in which the first resin is filled between the tip-side portion of the tip 23 of the core wire 20 and the loosely wound portion 43 of the coil member 40C, and a base-side filling section 53 in which the second resin, having a harder hardness than the first resin, is filled between the base-side portion of the tip 23 of the core wire 20, which is located closer to the base end than the tip-side portion, and the tightly wound portion 45 of the coil member 40C.

[0106] Furthermore, as shown in Figure 7, the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 is The stiffness change portion 31 provided at the tip portion 23 of the core wire 20 is positioned to coincide with the axial direction of the core wire 20. Furthermore, the boundary portion between the loosely wound portion 43 and the tightly wound portion 45 of the coil member 40C is also positioned to coincide with the axial direction of the core wire 20 with respect to the stiffness change portion 31 provided at the tip portion 23 of the core wire 20.

[0107] Furthermore, as shown in Figure 7, at least the outer circumference of the coil member 40C is covered with a resin cover 60 (the resin cover 60 covers the entire outer circumference of the coil member 40C and the outer circumference of the core wire 20), and the inner surface of the resin cover 60 is joined to at least the tip-side filling portion 51.

[0108] Furthermore, the resin-filled portion may have a tip-side filling portion 51 in which the first resin is filled between the tip portion 23 of the core wire 20 and the loosely wound portion 43 of the coil member 40C. In addition, the portion of the core wire 20 that is located closer to the base end than the tip portion 23 and the tightly wound portion 45 of the coil member 40C may be configured to have a gap (a configuration in which no resin is filled).

[0109] Furthermore, in the case where the base end filling portion 53 is absent and a gap exists as described above, the boundary portion between the tip end filling portion 51 and the gap, and the boundary portion between the loosely wound portion 43 and the tightly wound portion 45 of the coil member 40C are arranged to coincide with the rigidity change portion 31 in the axial direction of the core wire 20.

[0110] Furthermore, in this guide wire 10C, the tip portion 23 of the core wire 20 can be subjected to a change in bending strength by the stiffness change portion 31, and the resin-filled portion 50 can be subjected to a change in hardness at the boundary portion 55 between the tip-side filled portion 51 and the base-side filled portion 53, or at the boundary portion between the tip-side filled portion 51 and the void. In addition, the stiffness of the coil member 40C can be subjected to a change at the boundary portion between the loosely wound portion 43 and the tightly wound portion 45 of the coil member 40C.

[0111] As a result, the tip 11 of the guidewire 10 can be easily bent starting from the rigidity change portion 31 where the bending strength of the tip 23 of the core wire 20 changes, the boundary portion 55 where the hardness of the resin-filled portion 50 changes, or the boundary portion between the tip-side filling portion 51 and the void, and the boundary portion between the loosely wound portion 43 and the tightly wound portion 45 of the coil member 40C where the rigidity has changed. This allows the guidewire 10 to be easily inserted into bent or curved tubular organs, body cavities, etc.

[0112] Furthermore, in this embodiment, the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53, or the boundary portion between the tip-side filling portion 51 and the void, is positioned to coincide with the axial direction of the core wire 20 with respect to the rigidity change portion 31 provided at the tip portion 23 of the core wire 20.

[0113] According to the above embodiment, the stiffness-changing portion 31 at the tip 23 of the core wire 20, where the bending strength changes, and the boundary portion 55 between the tip-side filling portion 51 and the base-side filling portion 53 at the resin-filled portion 50, or the boundary portion between the tip-side filling portion 51 and the void, can be made to coincide in the axial direction. This makes the tip 11 of the guide wire 10 easier to bend, allowing the guide wire 10 to be inserted more easily into bent or curved tubular organs, body cavities, etc.

[0114] Furthermore, in this embodiment, at least the outer circumference of the coil member 40C is covered with a resin cover 60, and the inner surface of the resin cover 60 is joined to at least the tip-side filling portion 51.

[0115] According to the above embodiment, since the inner surface of the resin cover 60 is joined to at least the tip-side filling portion 51, it is possible to make it difficult for the resin cover 60 to shift position relative to the coil member 40C. That is, since the coil member 40C is sandwiched between the tip-side filling portion 51 which is filled inside the coil member 40C and the resin cover 60 which covers the outer circumference of the coil member 40C, it becomes difficult for the resin cover 60 to shift position relative to the coil member 40C.

[0116] Furthermore, if the resin-filled portion 50 has a tip-side filling portion 51 and a base-side filling portion 53, even if irregularities occur on the outer surface of the resin-filled portion 50 due to changes in the shrinkage rate of both filling portions 51 and 53, such irregularities can be covered by the resin cover 60.

[0117] Furthermore, when there is a tip-side filling portion 51 and a base-side filling portion 53, or when there is only a tip-side filling portion 51, the properties of the materials in each filling portion may make it difficult to coat the outer circumference of the coil member 40C and the resin filling portion 50 with a hydrophilic resin film 70 or the like. Even in such cases, the hydrophilic resin film 70 or the like can be coated onto the resin cover 60 covering the outer circumference of the coil member 40C, so the materials for the tip-side filling portion 51 and the base-side filling portion 53 can be freely selected.

[0118] It should be noted that the present invention is not limited to the embodiments described above, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of symbols]

[0119] 10, 10A, 10B, 10C guide wires 20 core wires 23 Tip 31. Part where stiffness changes 40,40C coil component 41 Wire rod 43. Sparsely wound portion 45. Tightly wound section 50 Resin-filled section 51 Tip-side filling section 53 Base end filling portion 55 Boundary part 60 resin cover 70 Hydrophilic resin membrane

Claims

1. A core wire having a base and a tip that is smaller in diameter than the base, A coil member attached to the outer circumference of the tip of the core wire, The core wire has a resin-filled portion between its tip and the coil member, where resin is filled between them. The tip portion of the core wire has a stiffness change portion in which the stiffness changes abruptly in the axial direction, and is formed such that the bending strength of the tip portion in the axial direction and the bending strength of the base portion in the axial direction are different, with the stiffness change portion as the boundary. The coil member has loosely wound sections formed along its entire length by winding wire at predetermined intervals. The resin-filled portion is A tip-side filling portion is provided between the tip-side portion of the core wire and the loosely wound portion of the coil member, in which the first resin is filled. A guide wire characterized by having a base-end portion of the core wire located closer to the base end than the tip portion of the tip portion, and a base-end filling portion in which a second resin having a hardness higher than that of the first resin is filled between the base-end portion of the tip portion of the coil member and the loosely wound portion of the coil member.

2. A core wire having a base and a tip that is smaller in diameter than the base, A coil member attached to the outer circumference of the tip of the core wire, The core wire has a resin-filled portion between its tip and the coil member, where resin is filled between them. The tip portion of the core wire has a stiffness change portion in which the stiffness changes abruptly in the axial direction, and is formed such that the bending strength of the tip portion in the axial direction and the bending strength of the base portion in the axial direction are different, with the stiffness change portion as the boundary. The coil member has a loosely wound portion formed by winding a wire at predetermined intervals and a tightly wound portion formed by winding a wire without intervals, wherein the loosely wound portion is located at the tip end and the tightly wound portion is located at the base end. The resin-filled portion is The core wire has a tip-side filling portion between the tip-side portion of the tip and the loosely wound portion of the coil member, in which the first resin is filled. A guide wire characterized in that it has a base-end filling portion between the base-end portion of the tip of the core wire, which is located closer to the base end than the tip-side portion, and the tightly wound portion of the coil member, in which a second resin having a hardness higher than the hardness of the first resin is filled, or there is a gap between the base-end portion of the tip of the core wire, which is located closer to the base end than the tip-side portion, and the tightly wound portion of the coil member.

3. The guide wire according to claim 1, wherein the boundary portion between the tip-side filling portion and the base-side filling portion is arranged to coincide with the rigidity change portion in the axial direction of the core wire.

4. The guide wire according to claim 2, wherein the boundary portion between the tip-side filling portion and the base-side filling portion, or the boundary portion between the tip-side filling portion and the gap, is arranged to coincide with the rigidity change portion in the axial direction of the core wire.

5. At least the outer circumference of the coil member is covered with a resin cover. The guide wire according to claim 1 or 3, wherein the inner surface of the resin cover is joined to the tip-side filling portion and the base-side filling portion.

6. At least the outer circumference of the coil member is covered with a resin cover. The guide wire according to claim 2 or 4, wherein the inner surface of the resin cover is joined to at least the tip-side filling portion.

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