Guide wire

Abstract

Provided is a guide wire that makes it possible to make a level difference at a boundary part smaller and make it unlikely that a medical instrument will get caught on the level difference. This guide wire 10 comprises: a core wire 20 that has a base part 21 and a tip end part 23 to which a tapered part 24 is provided; a first resin covering part 30 that is made of resin and that covers the outer periphery of the base part 21; a second resin covering part 40 that is made of resin and that covers the outer periphery of the tip end part 23; and a boundary covering part 60 that covers the outer periphery of a boundary part 50 between the first resin covering part 30 and the second resin covering part 40, wherein the boundary covering part 60 is disposed within a range which is from the base end 24a of the tapered part 24 and toward the base end 21b side of the base part 21.

Description

Guidewire

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

[0002] It has been common practice to insert catheters into tubular organs of the human body, such as the bile duct, pancreatic duct, blood vessels, ureter, and trachea, to inject medicinal fluids, to expand blocked tubular organs with balloon catheters, or to place stents. During these procedures, a guidewire is first inserted into the tubular organ and brought to a predetermined position, and then a medical device, such as a catheter, balloon catheter, or tube holding a stent, is guided and moved along the outer periphery of the guidewire.

[0003] For example, Patent Document 1 listed below describes a guidewire that includes a wire body having a core wire with a tapered portion, a resin coating layer covering the outer periphery of the distal end of the wire body, and an annular member provided on the proximal end side of the resin coating layer so as to fill a step space between the proximal end of the resin coating layer and the wire body, wherein the outer diameter of the distal end of the annular member and the outer diameter of the proximal end of the resin coating layer are substantially equal, and the distal end face of the annular member is joined to the proximal end face of the resin coating layer. Also, a annular member made of polyamide or the like is disposed midway around the outer periphery of the tapered portion of the core wire, with a coating layer made of silicone resin or the like interposed therebetween.

[0004] Japanese Patent Application Laid-Open No. 2008-307367

[0005] Incidentally, it is conceivable to use multiple resin layers covering the outer periphery of the core wire constituting the guide wire, with multiple resin layers separated by a tapered portion of the core wire as a boundary. Such a guide wire can be manufactured, for example, by tapering the distal end of the core wire to form a base portion and a tapered portion in the core wire (first step), then covering the outer periphery of the base portion of the core wire with a first resin layer (first covering portion) (second step), and further covering the outer periphery of the tapered portion of the core wire with a second resin layer (second covering portion) (third step).

[0006] However, it is conceivable that a step will occur at the boundary between the resin layer (first coating) that coats the outer periphery of the base end of the core wire and the resin layer (second coating) that coats the outer periphery of the tip end of the core wire where the tapered portion is provided. That is, in the second step, a part of the first coating that is located closer to the base end of the core wire than the base end of the tapered portion is scraped off, forming a thin portion in the first coating. From this state, by coating the outer periphery of the tapered portion of the core wire with the second coating in the third step, a step will be formed at the boundary between the first coating and the second coating due to the thin portion of the first coating.

[0007] As described above, the step that occurs at the boundary between multiple resin layers is positioned close to the radial direction (inner radial circumference) of the medical device into which the guide wire is inserted, and this can cause the medical device to get caught on the step when the medical device is moved while being guided by the guide wire from the base end to the tip end of the guide wire.

[0008] Therefore, an object of the present invention is to provide a guidewire that can prevent a medical instrument from getting caught on the boundary between multiple resin layers when the medical instrument is guided and moved.

[0009] In order to achieve the above object, the guide wire of the present invention comprises a core wire having a base portion and a tip portion provided with a tapered portion that reduces in diameter from the base portion toward the tip portion, a first resin coating portion made of resin that coats the outer periphery of the base portion of the core wire, a second resin coating portion made of resin that coats the outer periphery of the tip portion of the core wire, and a boundary coating portion that coats the outer periphery of the boundary portion between the first resin coating portion and the second resin coating portion, and is characterized in that the boundary coating portion is positioned within a range from the base end of the tapered portion of the core wire toward the base end side of the base of the core wire.

[0010] According to the present invention, the boundary covering portion is positioned within a range extending from the base end of the tapered portion of the core wire toward the base end of the base of the core wire, thereby making it possible to reduce the step at the boundary portion, and making it less likely for the medical device, such as a catheter, to get caught on the step at the boundary portion when moving the medical device via the guidewire or when inserting or pulling back the guidewire into the medical device.

[0011] Fig. 2 is a side view showing one embodiment of a guide wire according to the present invention. Fig. 3 is a cross-sectional view of the guide wire taken along a cutting line along the axial direction. Fig. 4 is an enlarged cross-sectional view of a main part of Fig. 2. Fig. 5 is a cross-sectional view taken along the line A-A in Fig. 2.

[0012] (One Embodiment of Guidewire) Hereinafter, one embodiment of the guidewire according to the present invention will be described with reference to the drawings.

[0013] As shown in Figures 1 and 2, the guide wire 10 of this embodiment includes a core wire 20 having a base portion 21 and a tip portion 23 with a tapered portion 24 that reduces in diameter from the base portion 13 toward the tip, a coil member 27 attached to the outer periphery of the tip portion 23 of the core wire 20, a first resin coating portion 30 (hereinafter simply referred to as the "first coating portion 30") made of resin that coats the outer periphery of the base portion 21, a second resin coating portion 40 (hereinafter simply referred to as the "second coating portion 40") made of resin that coats the outer periphery of the tip portion 23, and a boundary coating portion 60 that coats the outer periphery of a boundary portion 50 between the first coating portion 30 and the second coating portion 40.

[0014] As will be described in detail later, the first covering portion 30 is made up of an inner layer 31 and an outer layer 35 (see FIGS. 3 and 4), and the second covering portion 40 is made up of a tapered covering portion 41 and a coil covering portion 45 (see FIG. 2).

[0015] First, the core wire 20 will be described. In this embodiment, the base portion 21 of the core wire 20 is a round wire with a circular cross section, and extends a predetermined length with a constant outer diameter. A tapered portion 24 is provided, which extends from the tip 21a of the base portion 21 at a predetermined angle so as to gradually reduce in diameter toward the tip 23a of the core wire 20. Furthermore, a thin-diameter portion 25 having a constant outer diameter and formed in a straight line extends from the tip 24a of the tapered portion 24 toward the tip 23a of the core wire 20. The tapered portion 24 and the thin-diameter portion 25 form the tip portion 23 of the core wire 20.

[0016] Furthermore, the tip 23a of the tip portion 23 of the core wire 20 is the distal end farthest from the hand side of the guidewire operator, and the base end 21b of the base portion 21 is the proximal end closest to the hand side of the guidewire operator.

[0017] In addition, the terms "tip portion," "tip," and "tip side" in the above-mentioned core wire 20 and each of the components described below (first resin coated portion, second resin coated portion, boundary coated portion, etc.) refer to the distal end portion, distal end, and distal end side that are farthest from the hand of the guidewire operator, and the terms "base portion," "base end," and "base end side" refer to the proximal end portion, proximal end, and proximal end side that are closest to the hand of the guidewire operator.

[0018] The coil member 27 attached to the outer periphery of the tip portion 23 of the core wire 20 is a so-called loosely wound coil, which is made by winding a wire 27a of a predetermined diameter at predetermined intervals. The coil member 27 is attached to the outer periphery of the tip portion 23 of the core wire 20 by fixing its base end to the tip side of the tapered portion 24 via a fixing portion 28 and fixing its tip side to the tip side of the small diameter portion 25 via a fixing portion 29, while being disposed on the outer periphery of the tip portion 23 of the core wire 20.

[0019] The material for the wire 27a forming the core wire 20 and the coil member 27 may 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, stainless steel, or piano wire, or may be an X-ray opaque metal such as W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, or an alloy thereof. Of the above, it is preferable to use a Ni-Ti engaging alloy, a Ni-Ti-X alloy, or stainless steel.

[0020] Furthermore, the above-mentioned fixing portions 28, 29 can be made of, for example, a brazing material such as Sn or Ag brazing, an ultraviolet-curing acrylate resin, a silicone adhesive, a modified silicone adhesive, an epoxy resin adhesive, an acrylate adhesive, a urethane resin adhesive, or the like.

[0021] Next, the first resin coating 30 will be described in detail. As described above, the first coating 30 coats the outer periphery of the base portion 21 of the core wire 20. As shown in Figures 2 to 4, the first coating 30 in this embodiment includes an inner layer 31 that coats the outer periphery of the base portion 21 of the core wire 20 and that is adhesive to the core wire 20, and an outer layer 35 made of a fluorine-based resin that is adhesive to the inner layer 31. In addition, a thin portion 33b that is thinner than the remaining portion of the first coating 30 is provided at the tip portion of the first coating 30.

[0022] 3 and 4, the inner layer 31 has a two-layer structure consisting of a first inner layer 32 and a second inner layer 33 disposed on the outer periphery of the first inner layer 32. As shown in Fig. 2, the first inner layer 32 is attached to the outer periphery of the base portion 21 of the core wire 20 while being wound in a spiral shape.

[0023] On the other hand, the second inner layer 33 covers the first inner layer 32 (which can also be said to embed the first inner layer 32) and also covers the outer periphery of the base portion 21 of the core wire 20. As shown in Fig. 3, the second inner layer 33 has a thick portion 33a that covers the first inner layer 32 and a thin portion 33b that is connected to the distal side of the thick portion 33a and is thinner than the thick portion 33a (its length in the direction perpendicular to the axis of the guide wire 10 is shorter). This thin portion 33b constitutes the "thin portion" in the present invention.

[0024] 3, the first covering portion 30 is configured to cover the outer periphery of the core wire 20 such that the tip of the thin-walled portion 33b abuts against the base end 41b of the tapered covering portion 41 of the second covering portion 40. The outer periphery of the thin-walled portion 33b forms a step 51 at the boundary 50 between the first covering portion 30 and the second covering portion 40. A step 33c is provided between the thick-walled portion 33a and the thin-walled portion 33b.

[0025] Examples of materials that can be used for the first inner layer 32 and the second inner layer 33 include fluorine-based resins such as polyamideimide (PAI), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA, perfluoroalkoxyalkane), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE), polyurethane, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, and polyetherimide (PEI).

[0026] In this embodiment, both the first inner layer 32 and the second inner layer 33 are made of PAI. Furthermore, the first inner layer 32 and the second inner layer 33 are formed to have different colors (for example, the first inner layer 32 is formed in black and the second inner layer 33 is formed in white), so that the spiral pattern formed by the first inner layer 32 can be seen from the outside of the guidewire (see FIG. 1 ).

[0027] Similarly to the inner layer 31, the outer layer 35 also has a two-layer structure consisting of a first outer layer 36 and a second outer layer 37 disposed on the outer periphery of the first outer layer 36 (see FIGS. 3 and 4). That is, the first covering portion 30 of this embodiment has a four-layer structure consisting of the first inner layer 32, the second inner layer 33, the first outer layer 36, and the second outer layer 37.

[0028] The first outer layer 36 covers the outer periphery of the second inner layer 33 that constitutes the inner layer 31. The second outer layer 37 is a thread-like member that is wound around the outer periphery of the first outer layer 36 to cover the outer periphery of the first outer layer 36.

[0029] Examples of materials that can be used for the first outer layer 36 and the second outer layer 37 include fluorine-based resins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA, perfluoroalkoxyalkane), polyamideimide (PAI), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE), as well as polyurethane, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, and polyetherimide (PEI). In this embodiment, both the first outer layer 36 and the second outer layer 37 are formed from PFA.

[0030] Next, the second resin coating portion 40 will be described in detail. As described above, the second coating portion 40 coats the outer periphery of the tip portion 23 of the core wire 20. As shown in Fig. 2, the second coating portion 40 in this embodiment includes a tapered coating portion 41 that coats the outer periphery of the tapered portion 24 that constitutes the tip portion 23 of the core wire 20, and a coil coating portion 45 that coats the coil member 27 attached to the outer periphery of the tip portion 23 of the core wire 20.

[0031] The coil covering portion 45 is disposed on the outer periphery of the coil member 27 to cover the coil member 27, and is cap-shaped with a closed tip end 45a and an open base end 45b. The tip end 45a has a rounded curved surface, and the base end 45b is disposed on the tip end side of the tapered portion 24 of the core wire 20.

[0032] The tapered coating portion 41 is arranged so that its base end 41b is aligned with the base end 24b of the tapered portion 24 of the core wire 20, and is shaped to extend while gradually reducing in diameter toward the tip of the tapered coating portion 41. Furthermore, the tip portion 41a of the tapered coating portion 41 is a thick-walled portion that expands in diameter to have approximately the same outer diameter as the coil coating portion 45, and this tip portion 41a abuts and is bonded to the base end 45b of the coil coating portion 45. Furthermore, as shown in Figure 1, the tapered coating portion 41 is formed with a spiral pattern 42 that is visible from outside the guidewire.

[0033] Examples of materials that can be used for the tapered covering portion 41 include fluorine-based resins such as polytetrafluoroethylene (PTFE), polyamideimide (PAI), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA, perfluoroalkoxyalkane), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE), as well as polyurethane, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, and polyetherimide (PEI). In this embodiment, the tapered covering portion 41 is formed from a tube of PTFE, a heat-shrinkable fluororesin.

[0034] On the other hand, the material of the coil covering portion 45 may be, for example, polyurethane, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, etc., and in this embodiment, the coil covering portion 45 is made of polyurethane.

[0035] As described above, the first coating portion 30 and the second coating portion 40 are coated at predetermined locations on the outer periphery of the core wire 20, and a boundary portion 50 between the first coating portion 30 and the second coating portion 40 on the outer periphery of the core wire 20, i.e., the tip of the first coating portion 30 (here, the tip of the thin-walled portion 33b) and the base end of the second coating portion 40 (here, the base end 41b of the tapered coating portion 41) abut against each other, thereby forming a boundary portion 50 between the tip side of the first resin coating portion 30 and the base end side of the second resin coating portion 40, and creating a step 51 recessed to a predetermined depth from the outer periphery of the guidewire at the boundary portion 50.

[0036] The outer periphery of the boundary portion 50 between the first covering portion 30 and the second covering portion 40 is covered by a boundary covering portion 60. In this embodiment, the distal end of the first covering portion 30 is provided with a thin portion 33b that is thinner than the remaining portion of the first covering portion 30, and the boundary covering portion 60 is configured to cover the outer periphery of this thin portion 33b. Furthermore, in this embodiment, the boundary covering portion 60 is configured to also cover the outer periphery of the first covering portion 30 on the base end side of the thin portion 33b.

[0037] 3 , the boundary covering portion 60 in this embodiment covers the outer periphery of the step 51 of the boundary portion 50, i.e., the outer periphery of the thin portion 33b of the second inner layer 33 of the inner layer 31 constituting the first covering portion 30, and also covers the outer periphery of a portion that extends beyond the thin portion 33b and reaches the apex (outermost diameter portion) of the second outer layer 37 constituting the outer layer 35 of the first covering portion 30, the second outer layer 37 being disposed closest to the boundary portion 50. Note that the boundary covering portion 60 may be configured so that its coverage range for the first covering portion 30 extends toward the base end of the first covering portion 30 to cover the outer peripheries of multiple second outer layers 37.

[0038] Moreover, the boundary covering portion 60 in this embodiment has a substantially cylindrical shape in which the outer periphery 63 and the inner periphery 64 are both formed with a constant diameter (it can also be said that the outer periphery 63 and the inner periphery 64 are parallel to each other).

[0039] As shown in FIG. 3 , the inner periphery 64 of the boundary covering portion 60 abuts against and is bonded to the outer periphery of the thin-walled portion 33 b of the first covering portion 30, covering the outer periphery of the thin-walled portion 33 b, while the end face of the tip 61 abuts against and is bonded to the base end 41 b of the tapered covering portion 41 of the second covering portion 40, and the end face of the base end 62 abuts against and is bonded to (1) the step portion 33 c of the second inner layer 33 of the inner layer 31 constituting the first covering portion 30, (2) the tip of the first outer layer 36 of the outer layer 35, and (3) the outer periphery of the second outer layer 37 of the multiple second outer layers 37 of the outer layer 35 that is located closest to the boundary portion 50, so that the outer periphery of the step 51 at the boundary portion 50 is covered by the boundary covering portion 60.

[0040] In addition, it can also be said that the boundary covering portion 60 is filled to fill the concave space surrounded by the base end 41b of the tapered covering portion 41 of the second covering portion 40, the outer periphery of the step 51 of the boundary portion 50, the step portion 33c of the second inner layer 33, the tip end of the first outer layer 36, and the second outer layer 37 that is positioned closest to the boundary portion 50 among the second outer layers 37.

[0041] In addition, the boundary covering portion 60 has adhesive properties to at least the tapered covering portion 41, the second inner layer 33 of the inner layer 31 of the first covering portion 30, and the first outer layer 36 of the outer layer 35 of the first covering portion 30, and is able to adhere to each component due to its own adhesive properties.

[0042] That is, in this embodiment, the first coating portion 30 has a multilayer structure made up of multiple layers, and a tip end 61 of the boundary coating portion 60 is bonded to the second coating portion 40, and a base end 62 is bonded to the multiple layers (the second inner layer 33, the first outer layer 36, and the second outer layer 37) that make up the first coating portion 30. In this embodiment, with the boundary coating portion 60 covering the outer periphery of the step 51 at the boundary portion 50, the thin-walled portion 33b of the first coating portion 30 and the boundary coating portion 60 overlap (wrap) for a predetermined length in the axial direction of the core wire 20.

[0043] The outer diameter of the tip 61 of the boundary covering portion 60 is formed to be approximately the same as the outer diameter of the base end 41b of the tapered covering portion 41 of the second covering portion 40, and the tip 61 abuts against the base end 41b of the tapered covering portion 41 and is adhered to the two, so that there is a continuous shape with no steps between the outer periphery of the base end 41b of the tapered covering portion 41 and the outer periphery of the tip 61 of the boundary covering portion 60.

[0044] Furthermore, the outer diameter of the base end 62 of the boundary covering portion 60 is formed to be approximately the same as the outer diameter of the second outer layer 37 of the outer layer 35 that constitutes the first covering portion 30, and the base end 62 abuts against and is bonded to the step portion 33c of the second inner layer 33, the tip of the first outer layer 36, and the outer periphery of the second outer layer 37 that is positioned closest to the boundary portion 50, so that there is a continuous shape with no steps between the outer periphery of the base end 62 of the boundary covering portion 60 and the outer periphery of the second outer layer 37.

[0045] That is, the boundary covering portion 60 in this embodiment has an outer periphery 63 that is thinner than the outermost periphery of the first covering portion 30 (the outer periphery of the second outer layer 37 of the outer layer 35) and the outermost periphery of the second covering portion 40 (the outer periphery at the base end 41 b of the tapered covering portion 41). In other words, the boundary covering portion 60 does not have any part that is thicker than the outer peripheries of the first covering portion 30 and the second covering portion 40.

[0046] 3, the boundary covering portion 60 is arranged within a range W extending from the base end 24b of the tapered portion 24 of the core wire 20 toward the base end 21b of the base portion 21 of the core wire 20. That is, the boundary covering portion 60 is arranged within a predetermined range W extending from a position including the base end 24b of the tapered portion 24 toward the base end 21b of the base portion 21. For convenience of illustration, the end portion (right end) of the range W in FIG. 3 extending toward the base end 21b of the base portion 21 is omitted.

[0047] 3, the length L of the boundary covering portion 60 (the length along the axis of the boundary covering portion 60 (the direction along the axial direction of the core wire 20)) is preferably 1 mm or more, and more preferably 3 mm or more. If the length L of the boundary covering portion 60 is less than 1 mm, the amount of coverage of the boundary covering portion 60 on the step 51 at the boundary portion 50 tends to be insufficient, making it difficult to ensure the adhesive strength of the boundary covering portion 60 to the outer periphery of the step 51.

[0048] The length L of the boundary covering portion 60 refers to the length from the end face of the tip 61, which abuts against the base end 41 b of the tapered covering portion 41 of the second covering portion 40, to the maximum covering position of the boundary covering portion 60 with respect to the first covering portion 30. In this embodiment, the length L of the boundary covering portion 60 refers to the length from the end face of the tip 61 to the base end 62, which is located at the apex of the second outer layer 37 arranged closest to the boundary portion 50. However, when the boundary covering portion 60 covers multiple second outer layers 37, the length L of the boundary covering portion 60 refers to the length from the end face of the tip 61 to the second outer layer 37, among the multiple second outer layers 37, that is located closest to the base end of the first covering portion 30.

[0049] Furthermore, the maximum thickness T of the boundary covering portion 60 (here, the thickness at the tip 61 (the length in the direction perpendicular to the axis of the boundary covering portion 60)) is preferably 0.02 to 0.1 mm, and more preferably 0.03 to 0.05 mm. If the maximum thickness T of the boundary covering portion 60 is less than 0.02 mm, it becomes difficult to ensure the amount of protrusion of the boundary covering portion 60 from the outer periphery of the core wire 20 (the amount of protrusion of the boundary covering portion 60 radially outward, which can also be said to be the amount of build-up of the boundary covering portion 60) required to eliminate the step 51 at the boundary portion 50. If the maximum thickness T of the boundary covering portion 60 exceeds 0.1 mm, the amount of protrusion of the boundary covering portion 60 from the outer periphery of the core wire 20 becomes excessive.

[0050] Furthermore, the boundary covering portion 60 is configured to be integrated with the outer layer 35 of the first covering portion 30 and not have a smaller diameter than the outer layer 35 when covering the outer periphery of the boundary portion 50. Specifically, as shown in Fig. 3, when the outer periphery of the boundary portion 50 is covered by the boundary covering portion 60, the base end 62 of the boundary covering portion 60 is integrated with the first outer layer 36 of the outer layer 35 constituting the first resin covering portion 30 and the second outer layer 37 arranged closest to the boundary portion 50, and the outer periphery 63 of the boundary covering portion 60 is configured not to have a smaller diameter than the outer periphery of the second outer layer 37 of the outer layer 35 constituting the first resin covering portion 30.

[0051] Furthermore, examples of materials that can be used for the boundary coating portion 60 include fluorine-based resins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA, perfluoroalkoxyalkane), polyamideimide (PAI), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE), as well as polyetherimide (PEI). The boundary coating portion 60 in this embodiment is formed from the same material as the outer layer 35 of the first resin coating portion 30, which is a fluorine-based resin in this case, and more specifically, is formed from PFA.

[0052] Furthermore, although not specifically shown, a hydrophilic resin film such as polyvinylpyrrolidone, polyethylene glycol, methyl vinyl ether maleic anhydride copolymer, etc. may be coated on part or all of the outer periphery of each of the first resin coating portion 30, the second resin coating portion 40, and the boundary coating portion 60.

[0053] (Manufacturing Method of Guidewire) Next, an example of a manufacturing method of the guidewire configured as described above will be described. First, the first covering portion 30 is covered over the entire distal end portion 23 and proximal end portion 21 of the core wire 20 (first step). Next, the tapered portion 24 and the small diameter portion 25 are formed on the distal end side of the core wire 20 (second step). Note that, after the second step is completed, the core wire 20 has the first covering portion 30 covering the proximal end portion 21 located closer to the proximal end than the tapered portion 24, but the tapered portion 24 and the small diameter portion 25 are not covered with the first covering portion 30, leaving the core wire 20 exposed. After that, the tapered covering portion 41 is disposed on the tapered portion 24 of the core wire 20 and heat-shrunk to cover the tapered portion 24 (third step).

[0054] Next, the coil member 27 is attached to the tapered portion 24 and the small-diameter portion 25 of the core wire 20 via the fixing portions 28, 29, and the coil covering portion 45 is arranged to cover the coil member 27 (fourth step). Thereafter, the boundary covering portion 60 is arranged and bonded to the outer periphery of the step 51 at the boundary portion 50, and its distal end 61 is bonded to the second covering portion 40 and its proximal end 62 is bonded to the two layers (the second inner layer 33 and the first outer layer 36) of the first covering portion 30, thereby covering the outer periphery of the step 51 at the boundary portion 50 with the boundary covering portion 60, and the guidewire 10 is manufactured (fifth step).

[0055] (Variations) The shapes, structures, materials, layouts, etc. of the core wire, coil member, first resin coating portion, second resin coating portion, boundary portion, step, boundary coating portion, etc. that constitute the guide wire described above are not limited to the above embodiments.

[0056] The tip 23 of the core wire 20 in this embodiment has a tapered portion 24 and a thin-diameter portion 25, but the tip of the core wire may be, for example, (1) a tapered portion extending to the very tip of the core wire, (2) a plurality of tapered portions having different angles of inclination relative to the axis of the core wire, or (3) a combination of a plurality of tapered portions and one or more thin-diameter portions of a constant diameter, as long as it has at least a tapered portion.

[0057] Furthermore, the coil member 27 in this embodiment is a loosely wound coil that is loosely wound over the entire axial range from the base end to the tip, but the coil member may also be, for example, a coil having loosely wound portions and tightly wound portions, or a tightly wound coil that has only tightly wound portions over the entire axial range from the base end to the tip.

[0058] Furthermore, a gap is formed between the outer periphery of the tip portion 23 of the core wire 20 and the inner periphery of the coil member 27, but this gap may be filled with a resin material.

[0059] Furthermore, the first resin coating portion 30 in this embodiment has a four-layer structure consisting of an inner layer 31 and an outer layer 36, each of which has a two-layer structure. However, the first resin coating portion may, for example, be a single layer (one-layer structure) overall, or may have a structure in which the number of inner and outer layers is different (for example, two inner layers and three outer layers), or a structure in which an intermediate layer is provided between the inner and outer layers.

[0060] Furthermore, although the second resin-coated portion 40 in this embodiment has a two-component structure consisting of the tapered coating portion 41 and the coil coating portion 45, the second resin-coated portion may have, for example, a one-component structure or a multi-component structure consisting of three or more components. The second resin-coated portion may also have a multi-layer structure consisting of two or more layers, similar to the first resin-coated portion.

[0061] Furthermore, in this embodiment, a spiral pattern is applied to both the first resin coating portion 30 and the second resin coating portion 40, but, for example, a spiral pattern may be applied to only one of the first resin coating portion or the second resin coating portion, or neither the first resin coating portion nor the second resin coating portion may have a spiral pattern.

[0062] Furthermore, in this embodiment, the tip of the first resin coating portion 30 and the base end of the second resin coating portion 40 come into contact with each other, thereby forming a boundary portion 50 between the tip side of the first resin coating portion 30 and the base end side of the second resin coating portion 40, and creating a step 51 at the boundary portion 50. However, for example, the base end portion of the second resin coating portion may be overlapped axially by a predetermined length on the outer periphery of the tip end of the first resin coating portion, thereby forming a boundary portion and creating a step between the tip side of the first resin coating portion and the base end side of the second resin coating portion.

[0063] Furthermore, in this embodiment, the boundary coating portion 60 is configured so as not to have any portions that are thicker than the outer peripheries of the first coating portion 30 and the second coating portion 40, but the boundary coating portion may also be configured so as to have portions that are thicker than the first resin coating portion and the second resin coating portion.

[0064] 3, the outer periphery 63 of the boundary covering portion 60A may have a shape that bulges outward in the radial direction to form a convex curved surface, and the bulged outer periphery 63 may have a thickness that exceeds the outermost periphery of the first covering portion 30 (the outer periphery of the second outer layer 37 of the outer layer 35) and the outermost periphery of the second covering portion 40 (the outer periphery at the base end 41b of the tapered covering portion 41). Note that the outer periphery shape of the boundary covering portion is not limited to the above-described convex curved bulging shape, and may also be, for example, a shape that bulges out into a semicircular shape.

[0065] Furthermore, although the boundary coating portion 60 in this embodiment has a substantially cylindrical shape with both the outer periphery 63 and the inner periphery 64 formed with a constant diameter, for example, the outer periphery of the boundary coating portion 60 may be formed as a tapered inclined surface whose diameter gradually decreases from the tip to the base end. In this case, the outer periphery of the boundary coating portion has an inverse tapered shape whose diameter gradually decreases from the tip to the base end of the core wire, compared to the tapered portion 24 whose diameter gradually decreases toward the tip end 23 a of the core wire 20.

[0066] (Operation and Effect) Next, a method of using the guide wire of the present invention having the above-described structure will be described.

[0067] The guidewire 10 in this embodiment can be used to place a medical device such as a catheter or medical tube or to place a stent at a predetermined position in various tubular organs such as blood vessels, bile ducts, pancreatic ducts, ureters, and tracheas, or in human tissue such as a body cavity, and the location of use is not particularly limited. The following description will explain an example of a method for moving a medical device, such as a catheter, to a desired location in a tubular organ via a guidewire.

[0068] In use, the guidewire 10 is first inserted into a tubular organ from its distal end (the coil member 27 side) and pushed in until it reaches the desired location. Thereafter, the proximal end of the guidewire 10 is inserted into the distal end of a catheter, and the guidewire 10 is introduced into the catheter. The catheter is then moved while sliding and guiding from the proximal end side of the guidewire 10. The catheter may be moved along the guidewire 10 by appropriately repeating the steps of inserting the distal end of the guidewire 10 a predetermined distance from the distal end of the catheter and moving the catheter via the guidewire.

[0069] In this case, in the guide wire 10 of the present invention, the boundary coating portion 60 is arranged within a range W extending from the base end 24b of the tapered portion 24 of the tip portion 23 of the core wire 20 toward the base end 21b of the base portion 21 of the core wire 20.

[0070] As a result, the step 51 at the boundary portion 50, which is positioned close to the radial direction (inner radial circumference) of the medical device into which the guide wire 10 is inserted, can be made smaller, making it less likely that the medical device will get caught on the step 51 at the boundary portion 50 when moving the medical device such as a catheter through the guide wire 10 or when inserting or pulling back the guide wire 10 into the medical device.

[0071] In addition, in this embodiment, a thin-walled portion 33b is provided at the tip of the first covering portion 30, which is thinner than the remaining portions of the first covering portion 30, and the boundary covering portion 60 is configured to cover the outer periphery of the thin-walled portion 33b.

[0072] According to the above aspect, the boundary covering portion 60 covers the outer periphery of the thin-walled portion 33b of the first covering portion 30, so that the amount of protrusion of the boundary covering portion 60 relative to the outer periphery of the core wire 20 can be reduced, and the medical device can be made less likely to get caught on the step 51 at the boundary portion 50.

[0073] Furthermore, since the boundary covering portion 60 covers the outer periphery of the thin-walled portion 33b, the outer dimension (outer diameter) of the boundary covering portion 60 can be made small, which ensures a large clearance between the outer periphery of the boundary covering portion 60 and the inner periphery of the medical device, making it easier to insert the guide wire 10 into the medical device.

[0074] Furthermore, in this embodiment, the first coating portion 30 has an inner layer 31 that coats the outer periphery of the base portion 21 of the core wire 20 and is adhesive to the core wire 20, and an outer layer 35 made of a fluorine-based resin that is adhesive to the inner layer 31, and the boundary coating portion 60 is made of the same fluorine-based resin material as the outer layer 35 of the first coating portion 30.

[0075] According to the above aspect, since the first covering portion 30 and the boundary covering portion 60 have the above-mentioned configuration, the boundary covering portion 60 is firmly adhered to the outer layer 35 of the first covering portion 30, making it difficult for the boundary covering portion 60 to peel off from the first covering portion 30.

[0076] Furthermore, since the outer layer 35 of the first coating portion 30 and the boundary coating portion 60 are made of the same fluorine-based resin material, the hardness of both components can be made to be approximately the same, making it less likely for kinking to occur at the area between the outer layer 35 of the first coating portion 30 and the boundary coating portion 60.

[0077] Furthermore, in this embodiment, the boundary covering portion 60 is configured to be integrated with the outer layer 35 of the first covering portion 30 and not to have a smaller diameter than the outer layer 35 .

[0078] According to the above aspect, since the boundary covering portion 60 has the above configuration, the step between the first covering portion 30 and the boundary covering portion 60 can be reduced, making it less likely for the medical device to get caught on the boundary covering portion 60.

[0079] In this embodiment, as shown in FIG. 3, the boundary covering portion 60 is configured to also cover the outer periphery of the first covering portion 30 on the base end side of the thin-walled portion 33b.

[0080] According to the above aspect, since the boundary covering portion 60 has the above-mentioned configuration, the amount of overlap of the boundary covering portion 60 with the first covering portion 30 can be increased, making it possible to make the boundary covering portion 60 less likely to peel off from the first covering portion 30.

[0081] Furthermore, as shown by the dotted line in Figure 3, if the boundary covering portion 60A is configured to have a portion that is thicker than the first covering portion 30 and the second covering portion 40, the base end side of the second covering portion 40 will be located at the boundary portion 50 in a state where the diameter is smaller than the outer periphery of the boundary covering portion 60A, making it more difficult for the medical device to get caught on the second covering portion 40.

[0082] It should be noted that the present invention is not limited to the above-described embodiment, 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.

[0083] 10: Guide wire, 20: Core wire, 21: Base portion, 23: Tip portion, 24: Tapered portion, 27: Coil member, 30: First resin coated portion (first coated portion), 31: Inner layer, 33b: Thin portion, 35: Outer layer, 40: Second resin coated portion (second coated portion), 41: Tapered coated portion, 45: Coil coated portion, 50: Boundary portion, 51: Step, 60, 60A: Boundary coated portion.

Claims

1. A guidewire comprising: a core wire having a base portion and a tip portion provided with a tapered portion that reduces in diameter from the base portion toward the tip; a first resin coating portion made of resin that coats the outer periphery of the base portion of the core wire; a second resin coating portion made of resin that coats the outer periphery of the tip portion of the core wire; and a boundary coating portion that coats the outer periphery of the boundary portion between the first resin coating portion and the second resin coating portion, wherein the boundary coating portion is positioned within a range extending from the base end of the tapered portion of the core wire toward the base end of the base of the core wire.

2. A guide wire as claimed in claim 1, wherein the tip of the first resin-coated portion is provided with a thin-walled portion that is thinner than the remaining portion of the first resin-coated portion, and the boundary coating portion coats the outer periphery of the thin-walled portion.

3. The guidewire according to claim 2, wherein the boundary coating portion also coats the outer periphery of the first resin-coated portion on the proximal side of the thin-walled portion.

4. A guidewire as described in any one of claims 1 to 3, wherein the first resin coating portion has an inner layer that coats the outer periphery of the base of the core wire and that is adhesive to the core wire, and an outer layer made of a fluororesin that is adhesive to the inner layer, and the boundary coating portion is made of the same fluororesin material as the outer layer of the first resin coating portion.

5. A guide wire according to claim 4, wherein the boundary coating portion is configured to be integrated with the outer layer of the first resin coating portion and not to have a smaller diameter than the outer layer.

6. A guide wire according to any one of claims 1 to 3, wherein the boundary coating portion has a portion that is thicker than the outer periphery of the first resin coating portion and the second resin coating portion.

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