Guidewire

Abstract

In a guidewire, while ensuring the inner cavity formed between a core shaft and a coil body, the good flexibility of the front end portion of the guidewire is maintained, and the rotation performance is improved. The guidewire comprises: a core shaft; and a stranded wire coil body, wherein the stranded wire coil body is composed of a stranded wire formed by twisting a plurality of wires and is arranged on the outer periphery of the core shaft. In addition, the stranded wire coil body includes a front end, and has a front end portion including a characteristic portion, and a base end portion. The outer diameter of the stranded wire coil body in the characteristic portion is smaller than the outer diameter of the stranded wire coil body in the base end portion. In addition, the cross-sectional area of ​​the wire having the largest distance from the center point of the core shaft among the plurality of wires on the cross section of the stranded wire coil body in the characteristic portion, i.e., the outermost wire, is smaller than the cross-sectional area of ​​the wire having the largest distance from the center point of the core shaft among the plurality of wires on the cross section of the stranded wire coil body in the base end portion. In addition, the inner diameter of the stranded wire coil body is constant.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a guide wire inserted into a blood vessel or the like. Background Art

[0002] The method of using a catheter is widely used as a method for treating or inspecting a stenosis or occlusion (hereinafter referred to as a "lesion") in a blood vessel or the like. In general, a guide wire is used to guide a catheter to a lesion in a blood vessel or the like. The guide wire comprises a core shaft and a coil body arranged so as to surround the outer circumference of the core shaft. The guide wire is required to have, for example, a rotational performance of transmitting a rotational force applied to the base end side portion of the guide wire to the front end side portion, and good flexibility at the front end side portion of the guide wire. In addition, an inner cavity is formed between the core shaft and the coil body in order to configure components that can impart various properties to the guide wire.

[0003] In a conventional guide wire, the inner diameter of the coil body is made constant, and the outer peripheral surface of the coil body at the front end side of the guide wire is ground, so that the outer diameter of the guide wire gradually decreases toward the front end side (for example, refer to patent document 1). In addition, a guide wire including a stranded wire coil body composed of a plurality of wires is known (for example, refer to patent document 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Publication No. 2002-539901

[0007] Patent Document 2: Japanese Patent Application Publication No. 2009-337 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the existing guidewire in which the outer diameter of the guidewire is formed to gradually decrease toward the front end side, the single wire constituting the coil body becomes thinner on the front end side, so there is room for improvement in rotation performance. On the other hand, although the guidewire having a twisted wire coil body composed of twisted wires has improved rotation performance, the interference between the multiple wires constituting the twisted wires may lead to reduced flexibility (softness). In the guidewire having a twisted wire coil body, if the diameter of the wire constituting the twisted wire is reduced, the flexibility is improved, but the rotation performance may be reduced. In addition, if the existing twisted wire is used and wound in a manner that reduces the outer diameter of the twisted wire coil body on the front end side, the inner diameter of the twisted wire coil body also becomes smaller, making it difficult to ensure the inner cavity formed between the core shaft and the coil body. Therefore, it is desired that the guidewire maintains good flexibility of the front end portion of the guidewire and improves the rotation performance while ensuring the inner cavity formed between the core shaft and the coil body.

[0010] This specification discloses a technology that can solve at least one of the above-mentioned problems.

[0011] Means of solving problems

[0012] The technology disclosed in this specification can be realized in the following manner, for example.

[0013] (1) The guide wire disclosed in the present specification comprises: a core shaft; and a stranded wire coil body, wherein the stranded wire coil body is composed of a stranded wire formed by twisting a plurality of wires and is arranged in a manner to surround the outer circumference of the core shaft, the stranded wire coil body including a front end, and having a front end portion including a characteristic portion, and a base end portion; wherein the outer diameter of the stranded wire coil body in the characteristic portion is smaller than the outer diameter of the stranded wire coil body in the base end portion, and the cross-sectional area of ​​the wire among the plurality of wires that has the largest distance from the center point of the core shaft, i.e., the outermost wire, in the cross-sectional area of ​​the stranded wire coil body in the characteristic portion is smaller than the cross-sectional area of ​​the wire among the plurality of wires that has the largest distance from the center point of the core shaft, in the cross-sectional area of ​​the stranded wire coil body in the base end portion, and the inner diameter of the stranded wire coil body is constant.

[0014] The smaller the cross-sectional area of ​​the stranded wire coil body on the cross section of the guide wire, the higher the flexibility. In the guide wire, the inner diameter of the stranded wire coil body is constant, and the outer diameter of the stranded wire coil body in the characteristic portion is smaller than the outer diameter of the stranded wire coil body in the base end portion. In other words, on the cross section of the guide wire, the cross-sectional area of ​​the stranded wire coil body in the characteristic portion is smaller than the cross-sectional area of ​​the stranded wire coil body in the base end portion. Therefore, compared with the base end portion, the flexibility of the stranded wire coil body in the characteristic portion can be improved, and thus the flexibility of the guide wire can be improved.

[0015] The larger the diameter of the wire material of the stranded wire constituting the stranded wire coil body, the higher the rotation performance of the guide wire. In the guide wire, on the cross section of the stranded wire coil body in the characteristic portion, the cross-sectional area of ​​the outermost wire material among the multiple wire materials constituting the stranded wire is smaller than the cross-sectional area of ​​the outermost wire material on the cross section of the stranded wire coil body in the base end portion. That is, in the guide wire, the outer diameter of the stranded wire coil body can be reduced without uniformly reducing the diameter of one wire material constituting the stranded wire coil body throughout the stranded wire coil body. Therefore, the degree of reduction in the rotation performance of the guide wire can be reduced. In the guide wire, by making the inner diameter of the stranded wire coil body constant, the inner cavity formed between the core shaft and the coil body can be ensured. Therefore, through the guide wire, while ensuring the inner cavity formed between the core shaft and the coil body, the good flexibility of the front end portion of the guide wire can be maintained, and the rotation performance can be improved.

[0016] (2) In the above-mentioned guidewire, it can also be configured that, in at least one of the cross sections of the stranded wire coil body in the characteristic portion, the outermost wire constituting the characteristic portion has a gap between the adjacent wires. In order to improve the operability of the guidewire in a complexly curved blood vessel, the front end portion of the guidewire is sometimes bent using a fingertip or a device (for example, a shaping needle) for use, or the front end portion is restored to its original shape after use (hereinafter referred to as "shaping / reshaping"). Therefore, it is sometimes required that the front end portion of the guidewire be easily shaped / reshaped. In the guidewire of this structure, the outermost wire constituting the characteristic portion has a gap between the adjacent wires. Therefore, compared with a structure without this gap, interference between the wires can be suppressed, and the ease and flexibility of shaping / reshaping the stranded wire coil body in the characteristic portion can be improved. Therefore, with the guidewire of this structure, the ease and flexibility of shaping / reshaping the guidewire can be more effectively improved.

[0017] (3) In the above-mentioned guide wire, it can also be configured that, in the cross section of the stranded wire coil body in the characteristic portion, the outermost surface of the surface constituting the outermost wire is in a flat shape. In other words, in the guide wire of this structure, the outer peripheral surface of the stranded wire coil body in the characteristic portion has a flat surface. Therefore, compared with a structure in which the outer peripheral surface is in an arc shape, the guide wire can be in surface contact with a fingertip or a device (for example, a trimming needle), thereby improving the ease of trimming / re-trimming the stranded wire coil body in the characteristic portion. Therefore, through the guide wire of this structure, the ease of trimming / re-trimming of the guide wire can be more effectively improved.

[0018] (4) In the above-mentioned guide wire, it can also be configured that the characteristic portion includes a portion on the base end side where the cross-sectional area of ​​the outermost wire continuously decreases from the base end side toward the front end. In the guide wire of this structure, the stiffness of the stranded wire coil body gradually decreases in the portion where the cross-sectional area of ​​the outermost wire in the characteristic portion continuously decreases. According to the guide wire of this structure, since the base end side in the characteristic portion includes the above-mentioned portion, it is possible to suppress the reduction in rotational performance such as torque transmission and rotation tracking due to the sudden change in stiffness between the characteristic portion and the base end.

[0019] (5) In the above-mentioned guide wire, it can also be configured that the base end portion of the stranded wire coil body is formed as a whole with the characteristic portion. In a structure in which the base end portion of the stranded wire coil body is joined to the characteristic portion by a joint or the like, the rotational force transmitted from the base end portion is not smoothly transmitted to the characteristic portion, resulting in a decrease in rotational performance such as torque transmission and rotational tracking due to residual stress at the joint. On the other hand, according to the guide wire of this structure, since the base end portion of the stranded wire coil body is formed as a whole with the characteristic portion, the rotational force transmitted to the base end portion can be smoothly transmitted to the characteristic portion, thereby improving the rotational performance of the guide wire.

[0020] (6) In the guide wire described above, the surface roughness of the outermost surface of the outermost wire in the characteristic portion may be greater than the surface roughness of the inner peripheral surface of the stranded wire coil body in the characteristic portion. According to the guide wire of this structure, for example, in a structure in which the outer peripheral surface of the guide wire is covered with resin, since the surface area of ​​the outer peripheral surface of the stranded wire coil body is increased, the adhesion between the outer peripheral surface and the resin can be improved, thereby suppressing the resin from peeling off from the coil body.

[0021] It should be noted that the technology disclosed in this specification can be implemented in various ways, for example, in the form of a guide wire and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an explanatory diagram schematically showing the structure of the guide wire 100 in the first embodiment.

[0023] Figure 2 It is schematically shown Figure 1 An explanatory diagram of the XY cross-sectional structure of the guide wire 100.

[0024] Figure 3 It is schematically shown Figure 1 An explanatory diagram of the XY cross-sectional structure of the guide wire 100.

[0025] Figure 4 1 is an explanatory diagram schematically showing the structure of a guide wire 100A in the second embodiment.

[0026] Figure 5 It is an explanatory diagram schematically showing the XY cross-sectional structure of one strand 300B, 300C of the coil bodies 30B, 30C constituting the guide wire according to the modification. DETAILED DESCRIPTION

[0027] A. First Implementation Method:

[0028] A-1. Basic structure of guidewire 100:

[0029] Figure 1 , Figure 2 as well as Figure 3 Schematically shows the structure of the guide wire 100 in this embodiment. Figure 1 , the structure of the longitudinal section (YZ section) of the guide wire 100 is shown. Figure 2 In the Figure 1 The structure of the cross section (XY cross section) of the guide wire 100 at the position of II-II. Figure 3 Columns A, B, and C show Figure 1 The structure of the cross section (XY cross section) of the guide wire 100 at the position of IIIA-IIIA, the position of IIIB-IIIB, and the position of IIIC-IIIC. It should be noted that Figure 1 In FIG. 1 , a portion of the guide wire 100 is omitted. Figure 1 In the Z axis, the positive direction side is the front end side (distal side) to be inserted into the body, and the negative direction side is the base end side (proximal side) operated by doctors and other operators. Figure 1 , the guide wire 100 is shown to be in a straight line substantially parallel to the Z-axis direction as a whole, but the guide wire 100 has flexibility to the extent that it can be bent.

[0030] It should be noted that, in this specification, for the convenience of description, the guide wire 100 is set as Figure 1 In the state shown, the Z-axis direction is referred to as the "axial direction of the guide wire 100" or simply the "axial direction", and the rotation direction centered on the Z-axis is referred to as the "circumferential direction of the guide wire 100" or simply the "circumferential direction".

[0031] The guide wire 100 is a long medical device inserted into a blood vessel etc. to guide a catheter to a lesion (stenosis, occlusion) in the blood vessel etc. The total length of the guide wire 100 is, for example, about 1500 mm to 3000 mm, and the outer diameter of the guide wire 100 is, for example, about 0.5 to 1.2 mm.

[0032] The guide wire 100 includes a core shaft 10 , a coil body 30 , a distal end side joint portion 42 , a proximal end side joint portion 44 , and a resin portion 50 .

[0033] The core shaft 10 is a long strip-shaped member with a thin diameter at the front end and a thick diameter at the base end. More specifically, the core shaft 10 includes: a rod-shaped thin diameter portion 11; a rod-shaped thick diameter portion 13, the rod-shaped thick diameter portion 13 is located closer to the base end than the thin diameter portion 11 and has a larger diameter than the thin diameter portion 11; and a tapered portion 12, the tapered portion 12 is located between the thin diameter portion 11 and the thick diameter portion 13 and the diameter gradually increases from the boundary position with the thin diameter portion 11 toward the boundary position with the thick diameter portion 13. The shape of the cross section (XY cross section) at each position of the core shaft 10 can take any shape, for example, it can be circular or flat. The outer diameter of the thick diameter portion 13 is, for example, about 0.2 to 0.6 mm.

[0034] As a material for forming the mandrel 10, a known material is used, for example, a metal material is used, more specifically, stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloy, piano wire, nickel-chromium alloy, cobalt alloy, tungsten, etc. The mandrel 10 may be formed of the same material as a whole, or each part may be formed of different materials.

[0035] like Figure 1 and Figure 2 As shown, the coil body 30 is a coil-shaped component formed into a hollow cylindrical shape by winding a plurality of strands 300 into a spiral shape, and is arranged in a manner to surround the outer circumference of the core shaft 10. An inner cavity H is formed between the core shaft 10 and the coil body 30. In the present embodiment, the coil body 30 is a structure obtained by tightly winding eight strands 300. The coil body 30 has a base end BP and a front end AP including the front end of the coil body 30. The coil body 30 is an example of a stranded wire coil body in the claims, and the front end AP is an example of a front end and a characteristic portion in the claims. The detailed structure of the coil body 30 will be described later.

[0036] As the material for forming the coil body 30, a known material is used, for example, a metal material is used, more specifically, stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloy, piano wire, nickel-chromium alloy, cobalt alloy, tungsten, etc. are used. The plurality of strands 300 may be formed of the same material or different materials. In addition, the core wire 310 and the side wire 330 described later constituting the strand 300 may be formed of the same material or different materials.

[0037] The front end side joint 42 is a component that joins the front end of the core shaft 10 with the front end of the front end portion AP (specifically, the flat portion FP) of the coil body 30. That is, the front end of the core shaft 10 and the front end of the front end portion AP of the coil body 30 are fixed in a manner buried in the interior of the front end side joint 42. The outer peripheral surface of the front end side of the front end side of the front end side joint 42 is a smooth surface (for example, a roughly hemispherical surface). In addition, the base end side joint 44 is a component that joins the core shaft 10 with the base end of the base end BP of the coil body 30 at a specified position between the base end and the front end of the core shaft 10 along the axial direction. That is, the base end of the base end BP of the coil body 30 is fixed in a manner buried in the interior of the base end side joint 44.

[0038] The material forming the front end side joint portion 42 and the base end side joint portion 44 is a known material, for example, solder (aluminum alloy solder, silver solder, gold solder, etc.), metal brazing material (Ag-Sn alloy, Au-Sn alloy, etc.), adhesive (epoxy adhesive, etc.), etc. In the present embodiment, solder is used as the material forming the front end side joint portion 42 and the base end side joint portion 44.

[0039] The resin portion 50 is formed of resin and is a coating member covering the outer peripheral surface of the coil body 30, the front end side joint portion 42 and the base end side joint portion 44. As a material for forming the resin portion 50, a known material is used, for example, polyurethane, polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polyimide, polyvinyl propylene, PTFE and other fluorine resins, silicone resins, etc. are used. The thickness of the resin portion 50 is, for example, about 0.01 to 0.1 mm.

[0040] A-2. Detailed structure of the coil body 30:

[0041] Next, the detailed structure of the coil body 30 in the guide wire 100 of the present embodiment is described. As described above, the coil body 30 of the guide wire 100 of the present embodiment is composed of a plurality of strands 300 and has a base end BP and a front end AP. Each of the plurality of strands 300 constituting the coil body 30 is continuous from the base end BP to the front end AP. In other words, the base end BP and the front end AP are formed as one body. The outer diameter DE of the coil body 30 in the front end AP is smaller than the outer diameter DE of the coil body 30 in the base end BP. On the other hand, the inner diameter DI of the coil body 30 is approximately constant in both the base end BP and the front end AP. In addition, the outer diameter DF of the strand 300 is, for example, about 0.1 to 0.4 mm. It should be noted that the outer diameter DE is the diameter of the circumscribed circle OC of the coil body 30, and the inner diameter DI is the diameter of the inscribed circle IC of the coil body 30. In addition, the outer diameter DF of the strand 300 is the length on the radial direction RD of the core shaft 10.

[0042] The front end portion AP is composed of a tapered portion DP and a flat portion FP. The tapered portion DP is a portion continuous with the base end portion BP, and the flat portion FP is a portion continuous with the tapered portion DP and including the front end of the coil body 30. In the tapered portion DP, the outer diameter DE of the coil body 30 continuously decreases from the base end side toward the front end side. On the other hand, in the flat portion FP, the outer diameter DE of the coil body 30 is approximately constant from the base end side to the front end side. That is, the outer diameter DE of the tapered portion DP at the base end side is equal to the outer diameter DE of the base end portion BP at the front end side, and the outer diameter DE of the flat portion FP at the base end side is equal to the outer diameter DE of the tapered portion DP at the front end side. The tapered portion DP is an example of "a portion in which the cross-sectional area of ​​the outermost wire continuously decreases from the base end side toward the front end" in the claims.

[0043] use Figure 2 , the individual strands 300 constituting the coil body 30 are described. Figure 2 , a cross section of the coil body 30 in the base end portion BP is shown (hereinafter, also referred to as "the cross section of the base end portion BP"). It should be noted that Figure 2 The cross section of the coil body 30 shown is an example of a cross section of the coil body 30, and other cross sections may also be similar. Figure 2 The structure shown in the cross section of the coil body 30 shown in the figure is different from the structure shown in the cross section of the coil body 30. Below, one of the strands 300 constituting the coil body 30 (hereinafter referred to as the "specific strand 300X") is described, and the strands 300 other than the specific strand 300X also have the same structure as the specific strand 300X. The specific strand 300X has a two-layer structure in which a core wire 310 and a side wire 330 (hereinafter, the core wire 310 and the side wire 330 are sometimes collectively referred to as "wires 310, 330") are twisted together. Specifically, the specific strand 300X has a core wire 310 and six side wires 330 arranged around the core wire 310. In the cross section of the base end portion BP, the shapes of the wires 310, 330 are respectively approximately circular. In the cross section of the base end portion BP, the core wire 310 and the side wire 330 abut against each other, and in addition, adjacent side wires 330 abut against each other. More specifically, there is no gap between each side wire 330 and the adjacent side wire 330. The diameter D1 of each side wire 330 is, for example, about 0.01 to 0.1 mm. The wires 310 and 330 are examples of wires in the claims.

[0044] like Figure 2As shown in FIG. 1 , specifically, the side wires 330 constituting the specific stranded wire 300X include an outermost wire 331, a first outer wire 332, a second outer wire 333, a first inner wire 334, a second inner wire 335, and an innermost wire 336. The outermost wire 331 is a wire located at the farthest position from the center point O of the mandrel 10 in the radial direction RD among the six side wires 330. In other words, the outermost wire 331 is a wire having the largest distance from the center point O of the mandrel 10 among the six side wires 330. For example, the distance between the outermost wire 331 and the center point O of the mandrel 10 is the distance between the intersection point PO of the center point O and the outermost wire 331 on the virtual straight line VL passing through the center point O of the mandrel 10. The intersection point PO of the outermost wire 331 is an intersection point having a larger distance from the center point O among the intersection points of the virtual straight line VL and the outer edge of the outermost wire 331. The innermost wire 336 is the wire closest to the center point O of the mandrel 10 in the radial direction RD among the six side wires 330, and is the wire with the smallest distance from the center point O. The outer wires 332 and 333 are wires adjacent to the outermost wire 331, and the inner wires 334 and 335 are wires adjacent to the innermost wire 336. The outer wire 332 and the inner wire 334 are adjacent to each other, and the outer wire 333 and the inner wire 335 are adjacent to each other. Figure 2 In the cross section of the base end BP shown, the outer peripheral surface SO of the coil body 30 is composed of five wires 331, 332, 333, 334, and 335, and the inner peripheral surface SI of the coil body 30 is composed of three wires 334, 335, and 336. In the cross section of the base end BP, the size of the cross-sectional area A1 of the outermost wire 331 constituting the specific stranded wire 300X is substantially the same as the size of each cross-sectional area of ​​the other wires 332, 333, 334, 335, and 336. The outermost wire 331 is an example of the outermost wire in the claims.

[0045] use Figure 3 , a cross section of a specific strand 300X in the front end portion AP is described. Figure 3 In (A), a cross section of a specific strand 300X at the base end side in the tapered portion DP is shown. Figure 3 In (B), a cross section of a specific strand 300X at the front end side in the tapered portion DP is shown. Figure 3 (C) shows a cross section of the specific strand 300X in the flat portion FP. In the tapered portion DP and the flat portion FP, similarly to the base end portion BP, the specific strand 300X includes an outermost wire 331, a first outer wire 332, a second outer wire 333, a first inner wire 334, a second inner wire 335, and an innermost wire 336.

[0046] like Figure 3As shown in (A) to (C) of FIG. 1 , the outermost wire 331 in the tapered portion DP and the flat portion FP has a shape in which a portion of the outer peripheral side of the coil body 30 is missing compared to the outermost wire 331 in the base end portion BP. That is, the lengths Da, Db, and Dc (lengths in the radial direction RD) of the outermost wire 331 in the tapered portion DP and the flat portion FP are all smaller than the diameter D1 of the outermost wire 331 in the base end portion BP. Therefore, the lengths DA, DB, and DC of the specific stranded wire 300X in the tapered portion DP and the flat portion FP are all smaller than the outer diameter DF of the specific stranded wire 300X in the base end portion BP. In other words, the cross-sectional areas A1a, A1b, and A1c of the outermost wire 331 in the tapered portion DP and the flat portion FP are all smaller than the cross-sectional area A1 of the outermost wire 331 in the base end portion BP, and further, the cross-sectional area of ​​the specific stranded wire 300X in the tapered portion DP and the flat portion FP is smaller than the cross-sectional area of ​​the specific stranded wire 300X in the base end portion BP.

[0047] The length of the outermost wire 331 in the tapering portion DP is continuously reduced from the base end side toward the front end side (see Figure 1 and Figure 2 ). In other words, represented by the cross-sectional areas A1a and A1b, the cross-sectional area of ​​the outermost wire 331 in the tapering portion DP continuously decreases from the base end side toward the front end side. In addition, the length Dc of the outermost wire 331 in the flat portion FP is smaller than the length of the front end side of the tapering portion DP (for example, the length Db), and is approximately constant from the base end side to the front end side. In other words, the cross-sectional area A1c of the outermost wire 331 in the flat portion FP is smaller than the cross-sectional area of ​​the front end side of the tapering portion DP (for example, the cross-sectional area A1b), and is approximately constant from the base end side to the front end side.

[0048] In the decreasing portion DP and the flat portion FP, the outermost surface S31 of the outermost wire 331 is flat. It should be noted that the outermost surface S31 is the surface of the outermost wire 331 that is closest to the outer peripheral side in the radial direction RD, and is a surface that constitutes a part of the outer peripheral surface SO of the coil body 30. In the decreasing portion DP and the flat portion FP, the surface roughness of the outermost surface S31 of the outermost wire 331 is greater than the surface roughness of the inner peripheral surface of the innermost wire 336 (the inner peripheral surface SI of the coil body 30).

[0049] In this embodiment, the specific strand 300X in the tapered portion DP and the flat portion FP has a side wire 330 in which a part of the outer peripheral side of the coil body 30 is missing in addition to the outermost wire 331. Figure 3 As shown in (A), at the base end side of the tapered portion DP, the cross-sectional areas of the outer wires 332 and 333 are smaller than the cross-sectional areas of the outer wires 332 and 333 at the base end BP. Figure 3 (B) and Figure 3As shown in (C), in the front end side of the tapered portion DP and the flat portion FP, in addition to the outer wires 332 and 333, the cross-sectional areas of the inner wires 334 and 335 are also smaller than the cross-sectional areas of the inner wires 334 and 335 in the base end BP. It should be noted that the change in the cross-sectional area of ​​the outer wires 332 and 333 and the inner wires 334 and 335 in the tapered portion DP and the flat portion FP is the same as the change in the cross-sectional area of ​​the outermost wire 331. That is, in the tapered portion DP, the cross-sectional areas of the outer wires 332 and 333 and the inner wires 334 and 335 continuously decrease from the base end side toward the front end side, and in the flat portion FP, the cross-sectional areas of the outer wires 332 and 333 and the inner wires 334 and 335 are substantially constant from the base end side to the front end side. In the outer wires 332, 333 and the inner wires 334, 335, the outermost surfaces of the outer wires 332, 333 and the inner wires 334, 335 are also flat, and the surface roughness of the outermost surfaces is also greater than the surface roughness of the inner peripheral surface (the inner peripheral surface SI of the coil body 30) of the innermost wire 336. It should be noted that the cross-sectional areas of the core wire 310 and the innermost wire 336 in the tapered portion DP and the flat portion FP are substantially the same as the cross-sectional areas of the core wire 310 and the innermost wire 336 in the base end portion BP.

[0050] like Figure 3 (B) and Figure 3 As shown in (C), in the front end side of the tapering portion DP and the flat portion FP, there is a gap SP between the outermost wire 331 and the outer wires 332 and 333. Similarly, there is a gap SP between the outer wires 332 and 333 and the inner wires 334 and 335. In this embodiment, the size of the gap SP in the flat portion FP is larger than the size of the gap SP at the front end side of the tapering portion DP. Here, "having a gap SP" means that adjacent wires do not abut each other.

[0051] The method for manufacturing the coil body 30 in the guide wire 100 is as follows, for example: Specifically, the core wire 310 and six side wires having the shape of the innermost wire 336 are twisted together to produce a twisted wire (hereinafter referred to as an "unprocessed twisted wire").

[0052] Next, an unprocessed coil body is produced. The unprocessed coil body can be produced, for example, by winding a plurality of (eight in this embodiment) unprocessed stranded wires around a mandrel to form a coil shape, then removing the mandrel and cutting it into a predetermined length.

[0053] Next, the coil body 30 is manufactured. The coil body 30 can be manufactured, for example, in the following manner: one end of the unprocessed coil body (the portion forming the front end AP (the tapering portion DP and the flat portion FP) in the coil body 30) is immersed in an electrolyte, and the end is electrolytically ground to reduce its diameter. It should be noted that, strictly speaking, the adjustment of the shape of the tapering portion DP and the flat portion FP can be performed by adjusting the electrolytic grinding parameters to adjust the grinding amount. As electrolytic grinding parameters, the liquid temperature of the electrolyte, the liquid viscosity, the current value, the extraction speed when the unprocessed coil body is extracted from the electrolyte, etc. can be cited. The coil body 30 of the above-mentioned structure is manufactured by the above-mentioned manufacturing method.

[0054] It should be noted that the surface roughness of the outermost surface S31 of the outermost wire 331 of the stranded wire 300 constituting the coil body 30 can be increased by, for example, increasing the current value during electrolytic polishing.

[0055] A-3. Effects of the first embodiment:

[0056] As described above, the guide wire 100 of the present embodiment comprises: a core shaft 10; and a coil body 30, wherein the coil body 30 is composed of a stranded wire 300 formed by twisting wires 310 and 330, and is arranged in a manner surrounding the outer periphery of the core shaft 10. In addition, the coil body 30 has a front end portion AP and a base end portion BP. The outer diameter DE of the coil body 30 in the front end portion AP is smaller than the outer diameter DE of the coil body 30 in the base end portion BP. In addition, the cross-sectional areas A1a, A1b, and A1c of the outermost wire 331 on the cross section of the coil body 30 in the front end portion AP are smaller than the cross-sectional area A1 of the outermost wire 331 on the cross section of the coil body 30 in the base end portion BP. In addition, the inner diameter DI of the coil body 30 is constant.

[0057] The smaller the cross-sectional area of ​​the coil body on the cross section of the guide wire, the higher the flexibility. In the guide wire 100 of the present embodiment, the inner diameter DI of the coil body 30 is constant, and the outer diameter DE of the coil body 30 in the front end portion AP is smaller than the outer diameter DE of the coil body 30 in the base end portion BP. In other words, on the cross section of the guide wire 100, the cross-sectional area of ​​the coil body 30 in the front end portion AP is smaller than the cross-sectional area of ​​the coil body 30 in the base end portion BP. Therefore, compared with the base end BP, the flexibility of the coil body 30 in the front end portion AP can be improved, and then the flexibility of the guide wire can be improved.

[0058] The larger the diameter of the wire having the strands constituting the coil body, the higher the rotation performance of the guide wire. In the guide wire 100 of the present embodiment, on the cross section of the coil body 30 in the front end portion AP, the cross-sectional areas A1a, A1b, and A1c of the outermost wire 331 constituting the strands 300 (specific strands 300X) are smaller than the cross-sectional area A1 of the outermost wire 331 on the cross section of the coil body 30 in the base end portion BP. That is, in the guide wire 100 of the present embodiment, the outer diameter DE of the coil body 30 can be reduced without uniformly reducing the diameter of one wire constituting the coil body throughout the coil body. Therefore, the degree of reduction in the rotation performance of the guide wire 100 can be reduced. In the guide wire 100 of the present embodiment, by making the inner diameter DI of the coil body 30 constant, the inner cavity H formed between the core shaft 10 and the coil body 30 can be ensured. Therefore, according to the guide wire 100 of the present embodiment, it is possible to maintain good flexibility of the front end portion of the guide wire 100 while ensuring the inner cavity H formed between the core shaft 10 and the coil body 30 , and to improve the rotation performance.

[0059] In addition, in the guide wire 100 of the present embodiment, the strand 300 (specific strand 300X) is composed of a core wire 310 and a plurality of side wires 330. Since the core wire 310 surrounded by the side wires 330 does not constitute the outer peripheral surface SO on the entire coil body 30, it has a constant diameter on the entire coil body 30. In other words, the core wire 310 has no defects on the entire coil body 30. Therefore, the core wire 310 can help improve the rotation performance of the guide wire 100 on the entire coil body 30. In addition, in the guide wire 100 of the present embodiment, the innermost wire 336 constituting the strand 300 (specific strand 300X) has a constant diameter throughout the base end portion BP and the entire front end portion AP. Therefore, the innermost wire 336 can help improve the rotation performance of the guide wire 100 on the entire coil body 30. Therefore, by the guide wire 100 of the present embodiment, the rotation performance of the guide wire 100 can be more effectively improved.

[0060] In addition, in the guide wire 100 of the present embodiment, on the cross section of the coil body 30 in the front end AP, the outermost wire 331 constituting the front end AP has a gap SP with the adjacent wires (outer wires 332, 333). In order to improve the operability of the guide wire in a complexly curved blood vessel, the front end portion of the guide wire is sometimes bent using a fingertip or a device (e.g., a trimming needle) for use, or the front end portion is restored to its original shape after use (hereinafter referred to as "trim / re-trim"). Therefore, sometimes the ease with which the front end portion of the guide wire is trimmed / re-trim is required. In the guide wire 100 of the present embodiment, the outermost wire 331 constituting the front end AP has a gap SP with the adjacent wires (outer wires 332, 333). Therefore, compared with a structure without the gap, interference between the wires can be suppressed, and the ease and flexibility of trimming / re-trimming of the coil body 30 in the front end AP can be improved. Therefore, the guide wire 100 of the present embodiment can more effectively improve the ease of trimming / re-trimming and the flexibility of the guide wire 100 .

[0061] In addition, in the guide wire 100 of the present embodiment, on the cross section of the coil body 30 in the front end AP, the outermost surface S31 in the surface constituting the outermost wire 331 is in a flat shape. In other words, in the guide wire 100 of the present embodiment, the outer peripheral surface SO of the guide wire 100 in the front end AP has a flat surface (outermost surface S31). Therefore, compared with the structure of the outer peripheral surface (the outermost surface of the outermost wire) being an arc, the guide wire can be brought into surface contact with a fingertip or a device (e.g., a trimming needle), thereby improving the ease of trimming / re-trimming of the coil body 30 in the front end AP. Therefore, by the guide wire 100 of the present embodiment, the ease of trimming / re-trimming of the guide wire 100 can be more effectively improved.

[0062] In addition, in the guide wire 100 of the present embodiment, the front end portion AP includes a tapering portion DP on the base end portion BP side, in which the cross-sectional area (e.g., cross-sectional areas A1a, A1b) of the outermost wire 331 continuously decreases from the base end portion BP side toward the front end. In the guide wire 100 of the present embodiment, the stiffness of the coil body 30 gradually decreases in the tapering portion DP in the front end portion AP. According to the guide wire 100 of the present embodiment, since the base end portion BP side in the front end portion AP includes the tapering portion DP, it is possible to suppress the reduction in rotational performance such as torque transmission and rotation tracking due to a sudden change in stiffness between the front end portion AP and the base end BP.

[0063] In addition, in the guide wire 100 of the present embodiment, the base end BP of the coil body 30 is formed as a whole with the front end AP. In the structure in which the base end of the coil body is joined to the characteristic part by a joint or the like, the rotational force transmitted from the base end is not smoothly transmitted to the characteristic part, thereby causing the torque transmission, rotation tracking and other rotational performances to be reduced due to the residual stress at the joint. On the other hand, according to the guide wire 100 of the present embodiment, since the base end BP of the coil body 30 is formed as a whole with the front end AP, the rotational force transmitted to the base end BP can be smoothly transmitted to the front end AP, thereby improving the rotational performance of the guide wire 100.

[0064] In addition, in the guide wire 100 of the present embodiment, the surface roughness of the outermost surface S31 of the outermost wire 331 in the front end AP is greater than the surface roughness of the inner peripheral surface SI of the coil body 30 in the front end AP. According to the guide wire 100 of the present embodiment, the surface area of ​​the outer peripheral surface SO of the coil body 30 is increased, so the adhesion between the outer peripheral surface SO and the resin portion 50 can be improved, thereby suppressing the resin portion 50 from peeling off from the coil body 30, etc.

[0065] B. Second Implementation Method:

[0066] Figure 4 1 is an explanatory diagram schematically showing the structure of a guide wire 100A in the second embodiment. Figure 4 , the structure of the longitudinal section (YZ section) of the guide wire 100A is shown. Hereinafter, the same reference numerals are given to the same structures of the guide wire 100A of the second embodiment as those of the guide wire 100 of the first embodiment, and the description thereof will be appropriately omitted.

[0067] The guide wire 100A of the second embodiment includes a core shaft 10, a coil body 30A, a distal end side joint portion 42A, a proximal end side joint portion 44, and a resin portion 50. The guide wire 100A is different from the guide wire 100 of the first embodiment in that it includes a coil body 30A instead of the coil body 30 of the first embodiment.

[0068] The coil body 30A is a coil-shaped component formed into a hollow cylindrical shape by winding a plurality of twisted wires into a spiral shape, similarly to the coil body 30 of the first embodiment, and is configured in a manner surrounding the outer circumference of the core shaft 10. The coil body 30A has: a base end portion BP, and a front end portion AP including the front end of the coil body 30. In the present embodiment, the plurality of twisted wires constituting the coil body 30A are also connected to the front end portion AP from the base end portion BP, respectively. In other words, the base end portion BP and the front end portion AP are formed as a whole. The forming material of the coil body 30A is the same as that of the coil body 30. The coil body 30A is an example of a twisted wire coil body in the claims.

[0069] In the coil body 30A, the front end AP is composed of a tapering portion DP, a flat portion FP, and a head HP. The tapering portion DP is a portion continuous with the base end BP, and the flat portion FP is a portion continuous with the tapering portion DP at one end and continuous with the head HP at the other end. The head HP is a portion continuous with the flat portion FP and including the front end of the coil body 30A. Similar to the coil body 30 of the first embodiment, the outer diameter DE of the coil body 30A is continuously reduced from the base end side toward the front end side in the tapering portion DP, and is approximately constant from the base end side to the front end side in the flat portion FP. That is, the outer diameter DE at the base end side of the tapering portion DP is equal to the outer diameter DE at the front end side of the base end BP, and the outer diameter DE at the base end side of the flat portion FP is equal to the outer diameter DE at the front end side of the tapering portion DP. In other words, the outer diameter DE of the coil body 30A in the tapering portion DP and the flat portion FP is smaller than the outer diameter DE of the coil body 30A in the base end BP. On the other hand, the inner diameter DI of the coil body 30 is approximately constant in both the base end BP and the front end AP. The flat portion FP and the gradually decreasing portion DP are one example of a characterizing portion in the claims, and the gradually decreasing portion DP is one example of "a portion where the cross-sectional area of ​​the outermost wire material continuously decreases from the base end side toward the front end" in the claims.

[0070] In the head HP, the outer diameter DE of the coil body 30A is larger than the outer diameter DE of the flat portion FP, and at the front end side of the head HP, the outer diameter DE of the coil body 30A is equal to the outer diameter DE of the base end BP. The outer diameter DE at the base end side of the head HP is equal to the outer diameter DE at the front end side of the flat portion FP. The head HP is an example of the front end portion in the claims.

[0071] In the present embodiment, the front end side joint 42A is a member that joins the front end of the mandrel 10 with the front end of the front end portion AP (specifically, the head HP) of the coil body 30A. That is, the front end of the mandrel 10 and the front end of the front end portion AP of the coil body 30A are fixed in a manner embedded in the interior of the front end side joint 42A.

[0072] In the guide wire 100A of the second embodiment with the above-mentioned structure, the same effect as the first embodiment is also achieved. In addition, in the present embodiment, at the front end side of the head HP of the coil body 30A, none of the wire rods constituting the coil body 30A are defective. Therefore, in the coil body 30A of the present embodiment, the loosening of the stranded wire constituting the coil body 30A can be suppressed.

[0073] C. Modification:

[0074] The technology disclosed in this specification is not limited to the above-mentioned embodiment and modification examples, and can be modified into various forms within the scope not departing from the gist thereof. For example, the following modifications are also possible.

[0075] In the above embodiment, if Figure 3 As shown in (B) and (C) of FIG. 1 , although a structure is provided with a gap SP between the outermost wire 331 and the outer wires 332 and 333, the present invention is not limited to this. Figure 5 (A) schematically shows the Figure 3 (C) the same position ( Figure 1 The XY cross-sectional structure of the stranded wire 300B constituting the coil body 30B at the position of IIIC-IIIC. Figure 5 As shown in (A), a structure in which the stranded wire 300B abuts against the outermost wire 331B and the outer wires 332B and 333B may be adopted, that is, a structure without a gap SP may be adopted. In this structure, the outer diameter DE of the coil body 30B in the front end portion AP can be made smaller than the outer diameter DE of the coil body 30B in the base end portion BP, and the inner diameter DI of the coil body 30B can be made constant. In addition, the cross-sectional areas of the wires 331B, 332B, 333B, 334B, and 335B on the cross section of the coil body 30B in the front end portion AP are respectively smaller than the cross-sectional areas of each wire in the base end portion BP. Therefore, in this structure, the same effect as the above-mentioned embodiment can be achieved.

[0076] In the above embodiment, if Figure 3 As shown in (A) to (C) of FIG. 1 , although the outermost surface S31 of the outermost wire 331 is configured to be flat, the present invention is not limited to this. Figure 5 (B) schematically shows the Figure 3 (C) the same position ( Figure 1 The XY cross-sectional structure of the stranded wire 300C constituting the coil body 30C at the position of IIIC-IIIC. Figure 5 As shown in (B), a structure in which the outermost surfaces of the wires 331C, 332C, 333C, 334C, and 335C constituting the stranded wire 300C are in an arc shape can also be adopted. In this structure, the outer diameter DE of the coil body 30C in the front end portion AP can be made smaller than the outer diameter DE of the coil body 30C in the base end portion BP, and the inner diameter DI of the coil body 30C can also be made constant. In addition, the cross-sectional areas of the wires 331C, 332C, 333C, 334C, and 335C on the cross section of the coil body 30C in the front end portion AP are respectively smaller than the cross-sectional areas of each wire in the base end portion BP. Therefore, in this structure, the same effect as the above-mentioned embodiment can be achieved.

[0077] In the above-mentioned embodiment, the coil body 30 is a structure obtained by tightly winding the stranded wire 300 formed by twisting the core wire 310 and six side wires 330, but the base end BP and / or the front end AP of the coil body 30 may also be a structure obtained by sparsely winding the stranded wire 300. In addition, in the above-mentioned embodiment, the coil body 30 is a structure formed into a hollow cylindrical shape by spirally winding eight stranded wires 300, but it may also be a structure formed into a hollow cylindrical shape by spirally winding one stranded wire 300, or a structure formed into a hollow cylindrical shape by spirally winding two to seven stranded wires 300 or nine or more stranded wires 300. In addition, the wires constituting the stranded wire are not particularly limited, as long as there are two or more. For example, it may be a structure in which the side wires are one to five, or seven or more, or it may be a structure in which the stranded wire does not have a core wire.

[0078] The guide wire 100 of the above-described embodiment may also have a structure that does not include the resin portion 50 or a structure that partially includes the resin portion.

[0079] In the guide wire 100 of the above-mentioned embodiment, the base end BP and the front end AP constituting the coil body 30 can also be formed separately. In this structure, it is preferred that the base end BP and the front end AP are joined by a joint portion, etc. As the material constituting the joint portion, known materials can be used, for example, solder (aluminum alloy solder, silver solder, gold solder, etc.), metal brazing filler metal (Ag-Sn alloy, Au-Sn alloy, etc.), adhesive (epoxy-based adhesive, etc.), etc. can be used.

[0080] In the above embodiment, all the strands 300 constituting the coil body 30 have the same structure as the specific strands 300X. However, the present invention is not limited thereto, and some of the strands 300 may not have the same structure as the specific strands 300X.

[0081] In the above-mentioned embodiment, the structure in which the outermost surface S31 of the outermost wire 331 is flat on the cross section of the coil body 30 in the front end AP is adopted, but it is not limited to this, and the outermost surface of the outermost wire can also have a shape such as an arc. In addition, it can also be a structure in which the surface roughness of the outermost surface S31 of the outermost wire 331 is equal to the surface roughness of the inner peripheral surface SI of the coil body 30 in the front end AP, or the surface roughness of the inner peripheral surface SI is greater than the surface roughness of the outermost surface S31.

[0082] In the above-mentioned embodiment, a component capable of imparting various properties may also be configured in the lumen H formed between the mandrel 10 and the coil body 30. As such a component, for example, a component that does not transmit X-rays, a component that can improve rotational performance, an auxiliary component that can improve trimming, a component that can improve safety, etc. can be cited. By configuring a component that does not transmit X-rays at the front end of the lumen H, the visual recognition under X-ray fluoroscopy can be improved, thereby improving the operability of the operator. As a component that does not transmit X-rays, for example, a single coil, a stranded wire coil, or a pipe formed by platinum, tungsten, etc. can be cited. In addition, as a component that can improve rotational performance, for example, a coil body, a stranded wire coil body, etc. can be cited. In addition, as an auxiliary component that can improve trimming, for example, a wire formed by stainless steel, annealed Ni-Ti, etc. can be cited. In addition, as a component that can improve safety, for example, a stranded wire body formed by stainless steel, etc. can be cited. By configuring a stranded wire body formed by stainless steel, the tensile strength in the guide wire can also be ensured.

[0083] In the above embodiment, the mandrel 10 includes a thin-diameter portion 11, a tapered portion 12, and a thick-diameter portion 13, but the shape of the mandrel 10 is not particularly limited, and the mandrel 10 may not have at least one of these three portions, and may have other portions in addition to these three portions. For example, the base end side of the thick-diameter portion 13 of the mandrel 10 may also be connected to a portion with a larger diameter than the thick-diameter portion 13.

[0084] The material of each component in the above embodiment is only an example, and various deformations are possible. In addition, the manufacturing method of the coil body in the above embodiment is only an example, and various deformations are possible. For example, in the above embodiment, the coil body 30 can also be made by chemical processing other than electrolytic grinding, grinding or grinding and other physical processing using an unprocessed coil body.

[0085] Description of Reference Numerals

[0086] 10: Mandrel, 11: Thin-diameter portion, 12: Tapered portion, 13: Thick-diameter portion, 30: Coil body, 30A: Coil body, 30B: Coil body, 30C: Coil body, 42: Front-end side joint portion, 42A: Front-end side joint portion, 44: Base-end side joint portion, 50: Resin portion, 100: Guide wire, 100A: Guide wire, 300: Stranded wire, 300B: Stranded wire, 300C: Stranded wire, 300X: Specific stranded wire, 310: Core wire, 330: Side wire, 331: Outermost wire, 331B, 332B, 333B, 334B, 335B: Wire, 331B: Outermost wire, 331C, 332C, 333C, 334C, 335C: Wire, 332 : first outer wire, 332A, 333A: outer wire, 333: second outer wire, 334: first inner wire, 335: second inner wire, 336: innermost wire, A1: cross-sectional area, A1a, A1b, A1c: cross-sectional area, AP: front end, BP: base end, D1: diameter, DA, DB, DC: length, DE: outer diameter, DF: outer diameter, DI: inner diameter, DP: decreasing portion, Da, Db, Dc: length, FP: flat portion, H: inner cavity, HP: head, IC: inscribed circle, O: center point, OC: circumscribed circle, PO: intersection point, RD: radial direction, S31: outermost surface, SI: inner peripheral surface, SO: outer peripheral surface, SP: gap, VL: virtual straight line.

Claims

1. A guide wire, comprising: Mandrel; and A stranded wire coil body, the stranded wire coil body being composed of a stranded wire formed by twisting a plurality of wires and being arranged so as to surround the outer periphery of the mandrel; the stranded wire coil body including a front end, and having a front end portion including a characteristic portion, and a base end portion; in, The outer diameter of the stranded wire coil body in the characteristic portion is smaller than the outer diameter of the stranded wire coil body in the base end portion, The cross-sectional area of ​​the outermost wire, which is the wire with the largest distance from the center point of the mandrel among the plurality of wires, on the cross-sectional area of ​​the stranded wire coil body in the characteristic portion, is smaller than the cross-sectional area of ​​the wire with the largest distance from the center point of the mandrel among the plurality of wires on the cross-sectional area of ​​the stranded wire coil body in the base end portion, The inner diameter of the stranded wire coil body is constant. In at least one of the cross sections of the stranded wire coil body in the characteristic portion, the outermost wire constituting the characteristic portion has a gap between the outermost wire and the adjacent wire.

2. The guide wire according to claim 1, wherein: In a cross section of the stranded wire coil body in the characteristic portion, the outermost surface among surfaces constituting the outermost wire material has a flat shape.

3. The guidewire according to claim 1 or 2, wherein: The characteristic portion includes, on the base end side, a portion where the cross-sectional area of ​​the outermost wire continuously decreases from the base end side toward the front end.

4. The guide wire according to claim 1 or 2, wherein: The base end portion of the stranded wire coil body is formed integrally with the characteristic portion.

5. The guide wire according to claim 3, wherein: The base end portion of the stranded wire coil body is formed integrally with the characteristic portion.

6. The guide wire according to claim 2, wherein: The surface roughness of the outermost surface of the outermost wire in the characteristic portion is greater than the surface roughness of the inner peripheral surface of the stranded wire coil body in the characteristic portion.

Images