Guide wire

Abstract

To improve flexibility and bending strength of a guide wire.SOLUTION: Provided is a guide wire including a core shaft. The core shaft includes a core wire, and an outer layer covering an outer periphery of the core wire. A distal end portion of the core shaft is formed with a recess dented toward a radial inside of the core shaft.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a guidewire. [Background technology]

[0002] Guidewires that are inserted into blood vessels or digestive organs and used for treatment or diagnosis of the human body have been known. Patent Document 1 describes a guidewire with a metal core and a coating material. Patent Document 2 describes a guidewire with a spiral groove at the tip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-46179 A [Patent Document 2] JP 2012-70980 A Summary of the Invention [Problem to be solved by the invention]

[0004] Guidewires need to be flexible enough to navigate curved blood vessels, but they also need to be strong enough to resist bending (flexural strength).

[0005] An object of the present invention is to improve the flexibility and bending strength of a guidewire. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) One form of the present invention is a guide wire having a core shaft. The core shaft includes a core wire and an outer layer covering the outer periphery of the core wire, and a recess is formed at the tip of the core shaft, the recess being recessed radially inward of the core shaft.

[0008] According to this configuration, the guidewire has an outer layer, and further, the outer layer is provided with a recess, thereby improving the flexibility and bending strength of the guidewire.

[0009] (2) In the guidewire of the above embodiment, the recess may penetrate through the outer layer.

[0010] According to this configuration, the recess penetrates the outer layer, thereby making it possible to further improve the flexibility of the guidewire.

[0011] (3) In the guidewire of the above embodiment, a plurality of recesses may be formed at the tip of the core shaft, and a ratio of the recesses to the outer periphery of the tip of the core shaft when viewed from a first direction along the radial direction of the core shaft may be different from a ratio of the recesses to the outer periphery of the core shaft when viewed from a second direction perpendicular to the first direction and along the radial direction of the core shaft.

[0012] With this configuration, the ratio of the recess to the outer circumference of the core shaft when viewed from a first direction is different from the ratio of the recess to the outer circumference of the core shaft when viewed from a second direction, making it possible to set the direction in which the core shaft is most likely to bend.

[0013] (4) In the guidewire of the above embodiment, the core shaft may include a straight portion having a substantially constant outer diameter in the axial direction, and a tapered portion provided on the base end side of the straight portion, the outer diameter of which decreases toward the tip end side of the core shaft, and a recess may be formed in the straight portion.

[0014] According to this configuration, by providing a recess in the straight portion, the flexibility of the tip portion of the guidewire can be further improved.

[0015] (5) In the guidewire of the above aspect, the core shaft may have a straight portion and a tapered portion having a recess formed therein.

[0016] According to this configuration, the provision of a recess in the tapered portion can further improve the flexibility of the distal end portion of the guidewire.

[0017] The present invention can be realized in various aspects, for example, in the form of a guidewire manufacturing method, a catheter, a catheter manufacturing method, an endoscope, a dilator, etc. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram illustrating a vertical cross section of the overall configuration of a guidewire according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating a perspective view of a core wire and an outer layer. [Diagram 3] FIG. 2 is an explanatory diagram illustrating a longitudinal section of a core wire and an outer layer. [Figure 4] FIG. 4 is an explanatory diagram illustrating a cross section taken along the line AA in FIG. [Diagram 5] FIG. 4 is an explanatory diagram illustrating a cross section taken along the line BB in FIG. 3; [Figure 6] 3 is an explanatory diagram of a core shaft observed from a first direction in FIG. 2. [Figure 7] 3 is an explanatory diagram of the core shaft observed from a second direction in FIG. 2. [Figure 8] 11 is an explanatory diagram illustrating a cross section of a core wire and an outer layer of a guidewire according to a second embodiment. FIG. [Figure 9] FIG. 11 is an explanatory view illustrating a cross section of a core wire and an outer layer of a guidewire according to a third embodiment. [Figure 10] FIG. 13 is an explanatory view illustrating a vertical cross section of a distal end portion of a guidewire according to a fourth embodiment. [Figure 11] FIG. 13 is an explanatory view illustrating a vertical cross section of a distal end portion of a guidewire according to a fifth embodiment. [Figure 12] FIG. 13 is an explanatory view illustrating a core wire and an outer layer of a guidewire according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] First Embodiment FIG. 1 is an explanatory diagram illustrating a longitudinal section of the overall configuration of the guidewire 1 of the first embodiment. The guidewire 1 will be described with reference to FIGS. 1 to 7. The sizes of the components of the guidewire 1 shown in FIGS. 1 to 7 are illustrative and may be expressed on a scale different from the actual size. Hereinafter, the end portion of each component of the guidewire 1 located on the tip side will be referred to as the "tip", and the portion including the "tip" and extending from the tip to the middle toward the rear end will be referred to as the "tip portion". Similarly, the end portion of each component located on the rear end side will be referred to as the "rear end", and the portion including the "rear end" and extending from the rear end to the middle toward the tip side will be referred to as the "rear portion".

[0020] The guidewire 1 is a medical device that is inserted into a blood vessel or the digestive tract and is used primarily for inserting other medical devices, such as a catheter, into the body.

[0021] The guidewire 1 includes a core shaft 10, a coil 50, a fixing portion 61, and a fixing portion 62. The core shaft 10 includes a core wire 20 and an outer layer 30. The outer layer 30 includes a recess 40 recessed toward the inside in the radial direction of the core wire 20.

[0022] The core wire 20 is a wire extending in the longitudinal direction of the guidewire 1. The core wire 20 is provided inside the outer layer 30, and extends between the front end and the rear end of the outer layer 30.

[0023] The material of the core wire 20 is not particularly limited, but may be, for example, stainless steel (SUS302, SUS304, SUS316, etc.), a superelastic alloy such as a Ni-Ti alloy, a piano wire, a nickel-chromium alloy, a cobalt alloy, platinum, gold, tungsten, tantalum, etc. It is preferable to use tantalum as the material of the core wire 20.

[0024] The outer layer 30 is a cylindrical member that covers the outer circumference of the core wire 20. The outer diameter of the outer layer 30 gradually decreases from the rear end side of the outer layer 30 toward the front end side. The outer layer 30 has a straight portion 31 at the front end side, the outer diameter of which is substantially constant in the axial direction of the outer layer 30. The outer layer 30 has a tapered portion 32 at the rear end side of the straight portion 31, the outer diameter of which decreases toward the front end side of the outer layer 30. The rear end of the straight portion 31 and the front end of the tapered portion 32 are connected. The straight portion 31 and the tapered portion 32 cover the outer circumference of the front end of the core wire 20. The straight portion 31 has a recess 40 that is recessed toward the radial inside of the outer layer 30. The recess 40 has a groove shape that extends along the circumferential direction of the outer layer 30, and a plurality of recesses 40 are formed along the longitudinal direction of the outer layer 30 at substantially equal intervals. The recesses 40 are formed side by side on one side (first region S1) and the other side (second region S2) in the circumferential direction of the outer periphery 33 of the outer layer 30. The recesses 40 arranged at approximately equal intervals on one side in the circumferential direction of the outer periphery 33 of the outer layer 30 are also called "recesses 41", and the recesses 40 arranged at approximately equal intervals on the other side are also called "recesses 42". The bending strength of the core shaft 10 is improved by the outer layer 30, while the flexibility is improved by providing the recesses 40 in the outer layer 30. Details of the recesses 40 will be described later.

[0025] The material of the outer layer 30 is not particularly limited, but examples of the material that can be used include stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, platinum, gold, tungsten, tantalum, etc. It is preferable to use stainless steel as the material of the outer layer 30.

[0026] The recess 40 can be formed by irradiating the outer periphery 33 of the outer layer 30 with a laser while rotating a member having the core wire 20 disposed inside the outer layer 30 around the longitudinal axis of the member. When forming the recess 40 with a laser, it is preferable that the melting point of the core wire 20 is higher than the melting point of the outer layer 30. The core shaft 10 may also be formed as a so-called clad material in which the core wire 20 and the outer layer 30 are joined by rolling or the like.

[0027] The coil 50 is a member formed of a wire wound in a spiral shape along the longitudinal direction of the core shaft 10. The coil 50 covers a part of the tip side of the outer periphery 33 of the outer layer 30. The tip end of the coil 50 is connected to the core wire 20 and the tip end of the outer layer 30 by a fixing part 61. The rear end of the coil 50 is connected to the outer periphery 33 of the outer layer 30 by a fixing part 62.

[0028] <Details of the recess 40> FIG. 2 is an explanatory diagram illustrating a perspective view of the core wire 20 and the outer layer 30. As described above, a plurality of recesses 40 are formed along the longitudinal direction of the outer layer 30, and each recess 40 is formed along the circumferential direction of the outer periphery 33 of the outer layer 30. In this embodiment, as shown in FIG. 2, FIG. 4, and FIG. 5, the outer periphery 33 of the outer layer 30 is divided into four regions in the circumferential direction (first region S1, second region S2, third region S3, and fourth region S4). The regions S1 to S4 are arranged in the circumferential direction of the outer periphery 33 and extend in the longitudinal direction of the outer layer 30. The regions S1 to S4 are arranged in the circumferential direction of the outer periphery 33 in the order of the first region S1, the third region S3, the second region S2, and the fourth region S4. The first region S1 and the second region S2 are not in contact with each other, but are in contact with the third region S3 and the fourth region S4, respectively. The third region S3 and the fourth region S4 are not in contact with each other, but are in contact with the first region S1 and the second region S2, respectively. Among the recesses 40, a plurality of recesses 41 are formed in the first region S1 along the longitudinal direction of the outer layer 30, at approximately equal intervals and parallel to each other. Each recess 41 is formed from the first region S1 to the third region S3 and the fourth region S4, and both ends 410 are located in the third region S3 and the fourth region S4, respectively. Among the recesses 40, a plurality of recesses 42 are formed in the second region S2 along the longitudinal direction of the outer layer 30, at approximately equal intervals and parallel to each other. Each recess 42 is formed from the second region S2 to the third region S3 and the fourth region S4, and both ends 420 are located in the third region S3 and the fourth region S4, respectively.

[0029] The recesses 41 and 42 are alternately formed in the third region S3 and the fourth region S4 along the longitudinal direction of the core shaft 10. In other words, the recesses 42 are formed between adjacent recesses 41 in the longitudinal direction of the outer layer 30. In the first region S1, only the recesses 41 are provided, and in the second region S2, only the recesses 42 are provided. For this reason, the core shaft 10 constituting the third region S3 and the fourth region S4 has a larger proportion of the recesses 40 and a smaller volume of the outer layer 30 than the core shaft 10 constituting the first region S1 and the second region S2. Since the volume of the outer layer 30 included in the third region S3 and the fourth region S4 is smaller than the volume of the outer layer 30 included in the first region S1 and the second region S2, the tip portion of the core shaft 10 is easily bent in the direction in which the third region S3 and the fourth region S4 are located. On the other hand, in this embodiment, the volume of the outer layer 30 included in the first region S1 and the second region S2 is larger than the volume of the outer layer 30 included in the third region S3 and the fourth region S4, so that the tensile strength in the longitudinal direction of the core shaft 10 can be improved.

[0030] In the first region S1, the distance between adjacent recesses 41 (the shortest distance in the longitudinal direction of the outer layer 30) is called "distance L1", and in the second region S2, the distance between adjacent recesses 42 is called "distance L2". The recesses 41 are formed so as to be parallel to each other at equal intervals in the longitudinal direction of the outer layer 30. That is, the distance L1 between adjacent recesses 41 is approximately the same. The recesses 42 are formed so as to be parallel to each other at equal intervals in the longitudinal direction of the outer layer 30. That is, the distance L2 between adjacent recesses 42 is approximately the same. In addition, in the third region S3 and the fourth region S4, the distance between adjacent recesses 41 and recesses 42 is called "distance L3". In the longitudinal direction of the outer layer 30, adjacent recesses 41 and recesses 42 are formed so as to be equally spaced. That is, the distance L3 between each adjacent recess 41 and recess 42 is approximately the same.

[0031] A direction in which the first region S1 is viewed from the front and which is along the radial direction of the core shaft 10 of the outer layer 30 is referred to as a "first direction V1", and a direction in which the third region S1 is viewed from the front and which is along the radial direction of the core shaft 10 and perpendicular to the first direction V1 is referred to as a "second direction V2". An explanatory diagram of the core shaft 10 observed from the first direction V1 is shown in Fig. 6, and an explanatory diagram of the core shaft 10 observed from the second direction V2 is shown in Fig. 7. Figs. 6 and 7 will be described later.

[0032] FIG. 3 is an explanatory diagram illustrating a longitudinal section of the core wire 20 and the outer layer 30. In this embodiment, the recesses (41, 42) are slits penetrating the outer layer 30. The side wall of the recess 41 extending between the outer periphery 33 and the inner periphery 34 of the outer layer 30 is called the "side wall 411", and the side wall of the recess 42 extending between the outer periphery 33 and the inner periphery 34 of the outer layer 30 is called the "side wall 421". The side walls (411, 421) are formed approximately perpendicular to the axis C1 of the core wire 20. The distance of the recess 41 in the radial direction of the outer layer 30 is called the "depth T1", and the distance of the recess 42 in the radial direction of the outer layer 30 is called the "depth T2". The depth T1 of the recess 41 and the depth T2 of the recess 42 are approximately the same as the thickness of the outer layer 30. The length of the recess 41 in the longitudinal direction of the outer layer 30 is referred to as "width W1," and the length of the recess 42 in the longitudinal direction of the outer layer 30 is referred to as "width W2." The width W1 of the recess 41 is smaller than the depth T1, and the width W2 of the recess 42 is smaller than the depth T2.

[0033] Fig. 4 is an explanatory diagram illustrating the AA cross section of Fig. 3. In Fig. 4, the length of the recess 41 in the circumferential direction of the outer layer 30 is referred to as the "circumferential length CL1". The circumferential length CL1 of the recess 41 is greater than half the circumferential length of the outer periphery 33 of the outer layer 30. In other words, the angle α between the line connecting one end 410 of the recess 41 and the axis C1 of the core wire 20 and the line connecting the other end 410 of the recess 41 and the axis C1 of the core wire 20 is 180°<α<360°.

[0034] Fig. 5 is an explanatory diagram illustrating the cross section BB of Fig. 3. In Fig. 5, the length of the recess 42 in the circumferential direction of the outer layer 30 is referred to as the "circumferential length CL2". The circumferential length CL2 of the recess 42 is greater than half the circumferential length of the outer periphery of the outer layer 30. In other words, the angle β between the line connecting one end 420 of the recess 42 and the axis C1 of the core wire 20 and the line connecting the other end 420 of the recess 42 and the axis C1 of the core wire 20 is 180°<β<360°.

[0035] As described above, the circumferential length CL1 of the recess 41 (FIG. 4) and the circumferential length CL2 of the recess 42 (FIG. 5) are greater than half the circumferential length of the outer periphery 33 of the outer layer 30. This forms the third region S3 and the fourth region S4 in which both the recess 41 and the recess 42 are provided, as described above.

[0036] FIG. 6 is an explanatory diagram of the core shaft 10 observed from the first direction V1 in FIG. 2. When the core shaft 10 is observed from the first direction V1, the core wire 20 (FIG. 1), the recesses 40 (41, 42), and the outer periphery 33 of the outer layer 30 are observed, but the core wire 20 is omitted in FIG. 6. In the core shaft 10 observed from the first direction V1, the apparent area of ​​the recesses 40 (41, 42) is called "area As1", and the projected area of ​​the outer periphery 33 of the outer layer 30 in the first direction V1 is called "area Ac1". In FIG. 6, a part of the area As1 of the recesses 41 and a part of the area Ac1 of the outer layer 30 are shown. Here, the apparent area of ​​the outer periphery of the core shaft 10 observed from the first direction V1 is the sum (As1t+Ac1t) of the sum of the areas As1 of the recesses 40 (41, 42) and the sum of the projected areas Ac1 of the outer layer 30, "Ac1t". In this case, the ratio R1 of the recess 41 to the outer periphery of the core shaft 10 observed from the first direction V1 is R1 = As1t / (As1t+Ac1t) It can be expressed as follows:

[0037] Fig. 7 is an explanatory diagram of the core shaft 10 observed from the second direction V2 in Fig. 2. When the core shaft 10 is observed from the second direction V2, the core wire 20 (Fig. 1), the recesses 40 (41, 42), and the outer periphery 33 of the outer layer 30 are observed, but the core wire 20 is omitted in Fig. 7. In the core shaft 10 observed from the second direction V2, the apparent area of ​​the recesses 40 (41, 42) is called "area As2", and the projected area of ​​the outer periphery 33 of the outer layer 30 is called "area Ac2". In Fig. 7, a part of the area As2 of the recesses 40 (41, 42) and a part of the area Ac2 of the outer layer 30 are shown. Here, the apparent area of ​​the outer periphery of the core shaft 10 observed from the second direction V2 is the sum (As2t+Ac2t) of the sum "As2t" of the areas As2 of the recesses 40 (41, 42) and the sum "Ac2t" of the projected areas Ac2 of the outer layer 30. In this case, the ratio R2 of the recesses 40 (41, 42) to the outer periphery of the core shaft 10 observed from the second direction V2 is R2 = (As2t) / (As2t+Ac2t) It can be expressed as follows:

[0038] The ratio R1 and the ratio R2 are different. That is, R1 ≠ R2. Specifically, the ratio R2 is greater than the ratio R1. This makes it easier for the tip portion of the core shaft 10 to bend in the second direction V2.

[0039] According to the guidewire 1 of the present embodiment described above, the bending strength of the core shaft 10 can be improved by covering the outer periphery of the core wire 20 with the outer layer 30. Furthermore, by providing the recess 40 in the outer layer 30, the flexibility of the core shaft 10 can be improved while maintaining the bending strength. As a result, a guidewire 1 having good flexibility and bending strength at the tip can be provided. The guidewire 1 has good flexibility and can easily advance through a curved blood vessel, and further has good bending strength and can reduce the possibility of the guidewire 1 being damaged by bending fracture even when inserted into a curved blood vessel.

[0040] The recess 40 penetrates the outer layer 30. This can further improve the flexibility of the core shaft 10.

[0041] The recess 40 is provided in the straight portion 31. This can further improve the flexibility of the distal end side of the guidewire 1.

[0042] <Second embodiment> 8 is an explanatory diagram illustrating a cross section of a core wire 20 and an outer layer 30B of a guidewire 1B of the second embodiment. The guidewire 1B is different from the guidewire 1 of the first embodiment in a circumferential length CL1b of a recess 41B. Description of parts of the configuration of the guidewire 1B that are common to the guidewire 1 will be omitted.

[0043] In this embodiment, the circumferential length CL1b of the recess 41B is approximately equal to half the circumferential length of the outer circumference 33 of the outer layer 30B. That is, the angle α2 between the line connecting one end 410 of the recess 41B and the axis C1 of the core wire 20 and the line connecting the other end 410 of the recess 41B and the axis C1 of the core wire 20 is α2≈180°. Although not shown, the circumferential length of the recess 42B is also approximately equal to half the circumferential length of the outer circumference 33 of the outer layer 30B. That is, the angle β between the line connecting one end 420 of the recess 42B and the axis C1 of the core wire 20 and the line connecting the other end 420 of the recess 42B and the axis C1 of the core wire 20 is β≈180°. As a result, in the longitudinal direction of the outer layer 30, the regions where both the recesses 41B and the recesses 42B are provided (the third region S3 and the fourth region S4) are linear along the longitudinal direction of the core shaft 10. The guidewire 1B can also be provided with a guidewire 1B having good flexibility and bending strength at the tip. The angles α2 and β may be 0°<α<180° and 0°<β<180°. In this case, in the longitudinal direction of the outer layer 30, there are no regions where both the recesses 41B and the recesses 42B are provided (the third region S3 and the fourth region S4), and instead there are regions where neither the recesses 41B nor the recesses 42B are present (the fifth region and the sixth region). Even in this case, the core shaft 10 can be configured such that the ease of bending differs between when the tip of the core shaft 10 is bent in the first direction V1 and when the tip of the core shaft 10 is bent in the second direction V2.

[0044] <Third embodiment> 9 is an explanatory diagram illustrating a cross section of the core wire 20 and outer layer 30C of a guidewire 1C of the third embodiment. The guidewire 1C differs from the guidewire 1 of the first embodiment in that the recesses (43, 44, 45, 46) are provided linearly along the longitudinal direction of the outer layer 30C. Descriptions of parts of the configuration of the guidewire 1C that are common to the guidewire 1 will be omitted.

[0045] The outer layer 30C has four recesses (43, 44, 45, 46). The recesses (43, 44, 45, 46) are provided linearly along the longitudinal direction of the outer layer 30C. In a cross section of the outer layer 30C, the recesses 43 and 45 are provided at positions opposing each other by 180 degrees with respect to the axis C1 of the core wire 20, and the recesses 44 and 46 are provided at positions opposing each other by 180 degrees with respect to the axis C1 of the core wire 20. The guidewire 1C also has good flexibility and bending strength at its tip.

[0046] <Fourth embodiment> 10 is an explanatory diagram illustrating a vertical cross section of a distal end portion of a guidewire 1D of a fourth embodiment. The guidewire 1D differs from the guidewire 1 of the first embodiment in that a recess 40D is provided in a tapered portion 32D of an outer layer 30D. Descriptions of parts of the configuration of the guidewire 1D that are common to the guidewire 1 will be omitted.

[0047] The recesses 40D are provided in the straight portion 31 and the tapered portion 32D. This makes it possible to improve the flexibility of the tip portion of the guidewire 1D including the tapered portion 32D. It is also possible to provide the guidewire 1D having good flexibility and bending strength at the tip portion.

[0048] <Fifth embodiment> 11 is an explanatory diagram illustrating a vertical cross section of a distal end portion of a guidewire 1E of a fifth embodiment. The guidewire 1E differs from the guidewire 1 of the first embodiment in that the number of recesses (41E, 42E) provided on the distal end side of the straight portion 31E is greater than the number of recesses (41E, 42E) provided on the rear end side of the straight portion 31E. Descriptions of parts of the configuration of the guidewire 1E that are common to the guidewire 1 will be omitted.

[0049] The recesses (41E, 42E) are provided in the straight portion 31E of the outer layer 30E, and are formed so that the number of recesses (41E, 42E) increases from the rear end side of the straight portion 31E toward the front end side. The distance L1e of the recesses 41E provided on the front end side of the straight portion 31E is smaller than the distance L1e of the recesses 41E provided on the rear end side of the straight portion 31E. In addition, the distance L2e of the recesses 42E provided on the front end side of the straight portion 31E is smaller than the distance L2e of the recesses 42E provided on the rear end side of the straight portion 31E. In addition, the distance L3e between the recesses 41E and the recesses 42E adjacent to each other on the front end side of the straight portion 31E is smaller than the distance L3e between the recesses 41E and the recesses 42E adjacent to each other on the rear end side of the straight portion 31E. Since the recesses (41E, 42E) are provided more toward the front end side of the straight portion 31E, the volume of the front end side of the straight portion 31E is smaller than the volume of the rear end side of the straight portion 31E. This allows the guidewire 1E to have a more flexible distal end.The guidewire 1E also has a distal end with good flexibility and bending strength.

[0050] As shown in this embodiment, the distance L1e, the distance L2e, and the distance L3e do not have to be constant in the longitudinal direction of the outer layer 30. For example, the distance L1e of the recess 41E provided on the rear end side of the straight portion 31E may be smaller than the distance L1e of the recess 41E provided on the tip side of the straight portion 31E.

[0051] Sixth embodiment 12 is an explanatory diagram illustrating the core wire 20 and the outer layer 30F of the guidewire 1F of the sixth embodiment. The guidewire 1F differs from the guidewire 1 of the first embodiment in that the recesses (41F, 42F) do not penetrate the outer layer 30F. Of the configuration of the guidewire 1F, descriptions of parts common to the guidewire 1 will be omitted.

[0052] The recesses 41F and 42F do not penetrate the outer layer 30F. That is, the depth T1f of the recesses 41 and the depth T2f of the recesses 42 are smaller than the thickness of the outer layer 30F. The guidewire 1F also has good flexibility and bending strength at the tip.

[0053] <Modification> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0054] <Variation 1> In the guidewires (1, 1B, 1C, 1D, 1E, 1F) of the first to sixth embodiments, the outer diameter of the core wire 20 is approximately constant along the longitudinal direction of the core wire 20. However, the outer diameter of the core wire 20 does not have to be approximately constant along the longitudinal direction of the core wire 20, and for example, the outer diameter of the core wire 20 may increase from the tip side toward the rear end side of the core wire 20.

[0055] <Variation 2> In the guidewires (1, 1B, 1C, 1D, 1E, 1F) of the first to sixth embodiments, the outer periphery of the core wire 20 is covered with the outer layer (30, 30B, 30C, 30D, 30E, 30F), but a part of the core wire 20 may not be covered with the outer layer (30, 30B, 30C, 30D, 30E, 30F). For example, the outer periphery of the rear end of the core wire 20 may not be covered with the outer layer (30, 30B, 30C, 30D, 30E, 30F).

[0056] <Variation 3> The guidewires (1, 1B, 1C, 1D, 1E, 1F) of the first to sixth embodiments may have a thin resin film covering the outer periphery of the outer layer (30, 30B, 30C, 30D, 30E, 30F). [Explanation of symbols]

[0057] 1...Guide wire 10...Core shaft 20…Core wire 30…outer layer 31…Straight section 32…Tapered section 40…Recess 41…Recess 42…Recess 410...End of recess 411...Side wall of recess 420...End of recess 421...Side wall of recess 50…Coil 60…Fixed part 61...Fixed part C1: Core axis CL1: Circumferential length of the recess CL2: Circumferential length of the recess L1: Distance between adjacent recesses L2: Distance between adjacent recesses L3: Distance between adjacent recesses V1: Radial direction of the core shaft V2: Radial direction of the core shaft S1…first area S2…Second area S3...Third area S4…4th area

Claims

1. A guidewire having a core shaft, The core shaft is The cable includes a core wire and an outer layer that covers the outer periphery of the core wire, A recess recessed toward the radially inner side of the core shaft is formed at the tip end of the core shaft. Guide wire.

2. 2. The guidewire of claim 1, The recess extends through the outer layer.

3. The guide wire according to claim 1 or 2, A plurality of the recesses are formed in the tip end portion of the core shaft, a ratio of the recess to the outer periphery of the tip end portion of the core shaft when viewed from a first direction along the radial direction of the core shaft is different from a ratio of the recess to the outer periphery of the core shaft when viewed from a second direction perpendicular to the first direction and along the radial direction of the core shaft; Guide wire.

4. The guide wire according to claim 1 or 2, The core shaft is a straight portion having a substantially constant outer diameter in the axial direction; a tapered portion provided on a base end side of the straight portion, the outer diameter of which decreases toward a tip end side of the core shaft, The recess is formed in the straight portion. Guide wire.

5. 5. The guidewire according to claim 4, The core shaft has the straight portion and the recessed portion formed in the tapered portion.

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