Guide wire

Abstract

To provide a guide wire capable of improving torque transmission property while retaining rigidity.SOLUTION: A guide wire 10 includes: a core wire 20 extending from a tip to a base end in a long axis direction X; and a coating layer 30 formed of a resin and coating at least the tip of the core wire 20. The guide wire further has: a tip fixing part 51 in which the coating layer 30 is fixed to the external surface of the core wire 20; a non-fixing part 52 which is positioned on a side closer to the base end than the tip fixing part 51 and in which the coating layer 30 is in slidably direct or indirect contact with the external surface of the core wire 20; and a base end fixing part 53 which is positioned on a side closer to the base end than the non-fixing part 52 and in which the coating layer 30 is fixed to the external surface of the core wire 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In intravascular treatment, a guidewire is used to guide a treatment device to a target location. The guidewire includes a core wire and a coating layer made of resin that covers at least a part of the core wire (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-90683 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the guidewire including the core wire and the covering layer, the covering layer is fixed to the core wire. Therefore, when the guidewire gets stuck in the blood vessel, both the core wire and the covering layer are immobilized, and it becomes difficult to transmit the torque applied to the base end of the guidewire to the tip end. When a gap is formed between the covering layer and the core wire, even if the guidewire gets stuck in the blood vessel, the core wire can move independently of the covering layer, so that the torque applied to the base end of the guidewire can be transmitted to the tip end. However, the covering layer is separated from the core wire, which may reduce the rigidity of the guidewire.

[0005] The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a guidewire that can improve torque transmissibility while maintaining rigidity. [Means for solving the problem]

[0006] The above object can be achieved by the invention described in (1) below.

[0007] (1) The guidewire of the present invention has a core wire extending in the longitudinal direction from the tip to the base end, and a coating layer formed of resin and covering at least the tip portion of the core wire, and is characterized in having a tip fixed portion in which the coating layer is fixed to the outer surface of the core wire, a non-fixed portion located proximal to the tip fixed portion and in direct or indirect contact with the outer surface of the core wire so as to be able to slide thereon, and a base fixed portion located proximal to the non-fixed portion and in which the coating layer is fixed to the outer surface of the core wire. Effect of the Invention

[0008] In the guidewire described in (1) above, even if the non-fixed portion is stuck, the coating layer located at the non-fixed portion can slide relative to the core wire, so that torque applied to the base end of the guidewire can be transmitted to a portion of the guidewire that is distal to the non-fixed portion. In addition, since the coating layer is in direct or indirect contact with the core wire at the non-fixed portion, a decrease in the rigidity of the guidewire due to the presence of the non-fixed portion can be suppressed. Therefore, the present guidewire can improve torque transmission while maintaining its rigidity.

[0009] (2) In the guidewire described in (1) above, the non-fixed portion may have a low-friction layer between the coating layer and the core wire, the low-friction layer being fixed to an outer surface of the core wire and in slidable contact with an inner surface of the coating layer, whereby the coating layer located in the non-fixed portion comes into contact with the low-friction layer having a low friction coefficient, improving slidability with the outer surface of the core wire.

[0010] (3) In the guidewire described in (1) above, the non-fixed portion may have a low-friction layer between the coating layer and the core wire, the low-friction layer being fixed to an inner surface of the coating layer and in slidable contact with an outer surface of the core wire, whereby the core wire located in the non-fixed portion comes into contact with the low-friction layer having a low friction coefficient, improving slidability with the coating layer.

[0011] (4) In the guidewire according to any one of (1) to (3) above, the coating layer may include a support fixed to a resin forming the coating layer, and a tip of the support may be located distal to a tip of the non-fixed portion, and a base end of the support may be located proximal to a base end of the non-fixed portion. This allows the entire portion of the guidewire that can move independently of the core wire in the coating layer to be supported by the support, thereby effectively preventing damage to the coating layer.

[0012] (5) In the guidewire described in (4) or (5) above, the support may be exposed to the inner surface of the coating layer at the non-fixed portion and be in slidable contact with the outer surface of the low friction layer fixed to the outer surface of the core wire. In this way, the support of the coating layer contacts the core wire at the non-fixed portion of the guidewire, improving the slidability between the coating layer and the outer surface of the core wire. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing a guidewire according to a first embodiment. [Diagram 2] FIG. 6 is a cross-sectional view showing a guidewire according to a second embodiment. [Diagram 3] FIG. 11 is a cross-sectional view showing a guidewire according to a third embodiment. [Figure 4] FIG. 11 is a cross-sectional view showing a guidewire according to a fourth embodiment. [Diagram 5] FIG. 11 is a cross-sectional view showing a modified example of the guide wire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that dimensions in the drawings may be exaggerated and may differ from actual dimensions for convenience of explanation. In this specification and the drawings, components having substantially the same functions are given the same reference numerals to avoid redundant explanation. In this specification, the side of the guidewire 10 that is inserted into a blood vessel is referred to as the "distal side," and the side that is operated is referred to as the "base side."

[0015] First Embodiment 1, the guidewire 10 according to the first embodiment is a device extending in a longitudinal direction X from a distal end to a proximal end, and includes a long core wire 20, a coating layer 30 covering at least the distal end (the entirety in this embodiment) of the core wire 20, and a low-friction layer 40 located between the core wire 20 and the coating layer 30. In FIG. 1, the distal end of the guidewire 10 is formed to be straight, but it may be formed to be curved.

[0016] The core wire 20 is a wire that is flexible and has a certain degree of rigidity. The core wire 20 has a large diameter section 23 with a substantially constant outer diameter, a small diameter section 25 located distally of the large diameter section 23 and having a smaller outer diameter than the large diameter section 23, and a tapered section 24 located between the large diameter section 23 and the small diameter section 25 and having a gradually decreasing outer diameter toward the distal end. The small diameter section 25 and the large diameter section 23 are formed via the tapered section 24, so that the rigidity of the core wire 20 decreases toward the distal end.

[0017] The cross-sectional shape of the core wire 20 is circular, but it does not have to be circular. The material from which the core wire 20 is made is not particularly limited as long as it is flexible and has a certain degree of rigidity, and examples of the material that can be used include metals such as Ni-Ti alloys, stainless steel, Cu alloys, and Al alloys, and resins.

[0018] The low-friction layer 40 is formed in a cylindrical shape so as to cover the outer surface of the core wire 20. The low-friction layer 40 is fixed to the outer surface of the core wire 20 in a predetermined range in the longitudinal direction X. Therefore, the low-friction layer 40 does not slide against the outer surface of the core wire 20. The tip of the low-friction layer 40 is located on the proximal side of the tip of the core wire 20, and the proximal end of the low-friction layer 40 is located on the distal side of the proximal end of the core wire 20. The low-friction layer 40 is formed, for example, by applying a coating agent containing a low-friction material to the outer surface of the core wire 20. The low-friction material is, for example, a silicone resin or a fluororesin such as polytetrafluoroethylene (PTFE).

[0019] The covering layer 30 has a resin layer 31 formed of a resin. The covering layer 30 covers the entire core wire 20 in the longitudinal axis direction X and the circumferential direction, and has a substantially constant outer diameter in the longitudinal axis direction X. The covering layer 30 may cover only a portion of the core wire 20. The outer diameter of the covering layer 30 may vary in the longitudinal axis direction X.

[0020] The material for forming the resin layer 31 is not particularly limited as long as it is a resin having flexibility, and for example, polyamide elastomer and / or polyamide resin, or polyester, polyester elastomer, polyurethane elastomer, polyurethane resin, etc. can be used. In this embodiment, since a part of the resin layer 31 moves independently of the core wire 20, it is preferable that the resin layer 31 is formed of a material having higher rigidity and tensile strength than the commonly used flexible polyurethane. For example, since polyamide has a wide hardness range, when the resin layer 31 is formed of polyamide, it can have high rigidity and tensile strength while having flexibility, and damage to the covering layer 30 can be suppressed.

[0021] The outer surface of the resin layer 31 may be coated with a lubricating resin to reduce frictional resistance when wet. The lubricating resin is preferably a hydrophilic material. Examples of the hydrophilic material include a block copolymer of glycidyl methacrylate and dimethylacrylamide.

[0022] In particular, the lubricating resin of the lubricating layer 31 is preferably an acrylic resin. The acrylic resin preferably contains a structural unit derived from a reactive monomer. The reactive monomer is preferably a (meth)acrylic acid ester having an epoxy group, and among them, it is preferable to include at least one selected from the group consisting of glycidyl acrylate, glycidyl methacrylate (GMA), 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, and β-methylglycidyl methacrylate, because it is easy to control the crosslinking or polymerization of the polymer, and glycidyl (meth)acrylate is more preferable, and glycidyl methacrylate (GMA) is even more preferable. In this specification, "(meth)acrylate" includes both acrylate and methacrylate. The reactive monomer may be used alone or in combination of two or more kinds.

[0023] In addition, the acrylic resin preferably has a structural unit (A) derived from a reactive monomer having an epoxy group and a structural unit (B) derived from a hydrophilic monomer, and more preferably consists of a structural unit (A) derived from a reactive monomer having an epoxy group and a structural unit (B) derived from a hydrophilic monomer.

[0024] Examples of the hydrophilic monomer include acrylamide and its derivatives, vinylpyrrolidone, acrylic acid, methacrylic acid and their derivatives, polyethylene glycol acrylate and its derivatives, monomers having sugar or phospholipid in the side chain, water-soluble monomers such as maleic anhydride, etc., and the hydrophilic monomer is preferably N,N-dimethylacrylamide (DMAA).The hydrophilic monomer may be used alone or in combination of two or more kinds.

[0025] The guide wire 10 has a tip fixed portion 51 in which the coating layer 30 is fixed to the outer surface of the core wire 20, a non-fixed portion 52 located proximal to the tip fixed portion 51 and in which the coating layer 30 is in slidable contact with the outer surface of the core wire 20, and a base end fixed portion 53 located proximal to the non-fixed portion 52 and in which the coating layer 30 is fixed to the outer surface of the core wire 20.

[0026] The distal end fixing portion 51 is a portion of the guidewire 10 including the core wire 20 and the covering layer 30 located distally of the distal end of the low-friction layer 40. In the distal end fixing portion 51, the covering layer 30 is fixed in close contact with the outer surface of the core wire 20 and does not slide relative to the outer surface of the core wire 20. The proximal end fixing portion 53 is a portion of the guidewire 10 including the core wire 20 and the covering layer 30 located proximal to the proximal end of the low-friction layer 40. In the proximal end fixing portion 53, the covering layer 30 is fixed in close contact with the outer surface of the core wire 20 and does not slide relative to the outer surface of the core wire 20.

[0027] The non-fixed portion 52 is a portion of the guidewire 10 that includes the core wire 20, the low friction layer 40, and the covering layer 30, located between the distal end fixing portion 51 and the proximal end fixing portion 53. In the non-fixed portion 52, the low friction layer 40 is fixed to the inner surface of the covering layer 30 and is in slidable contact with the outer surface of the core wire 20. The length L2 of the non-fixed portion 52 in the longitudinal direction X is preferably 1% to 50% of the total length L1 of the guidewire 10 in the longitudinal direction X. The total length L1 of the guidewire 10 in the longitudinal direction X is 300 mm to 6000 mm. When the guidewire 10 is for percutaneous coronary intervention, the total length L1 of the guidewire 10 is preferably 1800 mm to 2400 mm. When the guidewire 10 is for treating the lower limb arteries from the wrist artery, the total length L1 of the guidewire 10 is preferably 2600 mm to 5400 mm. The length L3 from the tip of the guidewire 10 to the tip of the non-fixed portion 52 along the longitudinal axis direction X is preferably 30 mm or more.

[0028] 1, the tip and base ends of non-fixed portion 52 are each located in large diameter portion 23 of core wire 20 (on the base end side of the base end of tapered portion 24). The tip of non-fixed portion 52 may be between the base end and tip of tapered portion 24, or may be on the tip side of the tip of tapered portion 24. The base end of non-fixed portion 52 may also be between the base end and tip of tapered portion 24, or may be on the tip side of the tip of tapered portion 24.

[0029] The resin layer 31 is formed, for example, by extrusion molding or dipping of a resin onto the outer surface of the core wire 20. At this time, in the non-fixed portion 52 of the guidewire 10, the resin layer 31 is in intimate contact with the outer surface of the low-friction layer 40 fixed to the outer surface of the core wire 20, but is not fixed to the low-friction layer 40 due to the low friction coefficient of the low-friction layer 40. Therefore, in the non-fixed portion 52 of the guidewire 10, the resin layer 31 is subjected to a force exceeding the maximum static friction force, and can easily slide against the outer surface of the low-friction layer 40.

[0030] As described above, the guidewire 10 according to the first embodiment includes the core wire 20 extending in the longitudinal direction X from the distal end to the proximal end, and the covering layer 30 formed of resin and covering at least the distal end of the core wire 20, and includes a distal fixed portion 51 in which the covering layer 30 is fixed to the outer surface of the core wire 20, a non-fixed portion 52 located on the proximal side of the distal fixed portion 51 and in direct or indirect contact with the outer surface of the core wire 20 so as to be able to slide, and a proximal fixed portion 53 located on the proximal side of the non-fixed portion 52 and in which the covering layer 30 is fixed to the outer surface of the core wire 20. As a result, even if the non-fixed portion 52 of the guidewire 10 gets stuck, the covering layer 30 located at the non-fixed portion 52 can slide relative to the core wire 20, so that the torque applied by the surgeon to the proximal end of the guidewire 10 can be transmitted to a portion on the distal side of the non-fixed portion 52 of the guidewire 10. Furthermore, since the coating layer 30 is in direct or indirect contact with the core wire 20 at the non-fixed portion 52, a decrease in the rigidity of the guidewire 10 due to the presence of the non-fixed portion 52 can be suppressed. As a result, the guidewire 10 can improve torque transmissibility while maintaining its rigidity. Note that the coating layer 30 in indirect slidable contact with the outer surface of the core wire 20 means that the coating layer 30 is in slidable contact with the outer surface of the core wire 20 via another member (the low-friction layer 40). In contrast, the coating layer 30 in direct slidable contact with the outer surface of the core wire 20 means that the coating layer 30 itself is in slidable contact with the outer surface of the core wire 20 directly, not via another member.

[0031] The non-fixed portion 52 has a low-friction layer 40 between the covering layer 30 and the core wire 20, and the low-friction layer 40 is fixed to the outer surface of the core wire 20 and in slidable contact with the inner surface of the covering layer 30. As a result, the covering layer 30 located at the non-fixed portion 52 comes into contact with the low-friction layer 40, which has a low friction coefficient, improving the slidability with the outer surface of the core wire 20.

[0032] <Second embodiment> The guidewire 10 according to the second embodiment differs from the first embodiment in that the low friction layer 40 is fixed to the covering layer 30 rather than to the core wire 20, as shown in FIG.

[0033] In the second embodiment, the low friction layer 40 is in slidable contact with the outer surface of the core wire 20 and is secured to the inner surface of the cover layer 30 .

[0034] The tip fixed portion 51 is located distally of the tip of the low-friction layer 40, and the base fixed portion 53 is located proximally of the base end of the low-friction layer 40. The non-fixed portion 52 is located in an area having the low-friction layer 40. In the non-fixed portion 52, the inner surface of the low-friction layer 40 is in slidable contact with the outer surface of the core wire 20, and the outer surface of the low-friction layer 40 is fixed to the inner surface of the coating layer 30.

[0035] When producing the guidewire 10 according to the second embodiment, a portion of the core wire 20 is covered with a tube made of a low-friction material (e.g., a PTFE tube), and with the distal and proximal ends of the core wire 20 left with areas not covered with the PTFE tube, a resin layer 31 is formed on the outer surfaces of the core wire 20 and the PTFE tube by extrusion molding or the like. As a result, the PTFE tube forms a low-friction layer 40 that is in slidable contact with the core wire 20 and fixed to the coating layer 30 (resin layer 31). The portion of the core wire 20 not covered with the PTFE tube and the resin layer 31 fixed in close contact with the core wire 20 form a distal fixing portion 51 and a proximal fixing portion 53.

[0036] As described above, in the second embodiment, the non-fixed portion 52 has the low-friction layer 40 between the coating layer 30 and the core wire 20, and the low-friction layer 40 is fixed to the inner surface of the coating layer 30 and is in slidable contact with the outer surface of the core wire 20. As a result, the core wire 20 located at the non-fixed portion 52 comes into contact with the low-friction layer 40, which has a low friction coefficient, and therefore the slidability with the coating layer 30 is improved.

[0037] <Third embodiment> As shown in FIG. 3, the guidewire 10 according to the third embodiment differs from the first embodiment (or the second embodiment) only in that the covering layer 30 includes a support 36.

[0038] In the third embodiment, the coating layer 30 has a support 36 fixed to the resin layer 31. The support 36 is a coil in which at least one metal wire is wound or a braid in which a plurality of metal wires are braided into a tubular shape. The cross-sectional shape of the metal wire is, for example, a circle, an ellipse, a rectangle, a square, or the like. Adjacent metal wires may be in contact with each other or may be separated from each other. The material forming the support 36 is not particularly limited as long as it is a flexible metal material, and various metal materials such as Ni-Ti alloys, stainless steel, Cu alloys, and Al alloys can be used. In this embodiment, the support 36 is fixed by being embedded in the resin layer 31. Therefore, the resin layer 31 is filled between the metal wires forming the support 36 with almost no gaps. Therefore, the non-fixed portion 52 is formed on the inner surface of the resin layer 31, not on the support 36.

[0039] Support 36 can increase the stiffness and tensile strength of coating layer 30 at non-fixed portion 52 of guidewire 10. Additionally, support 36 does not inhibit proper twisting of coating layer 30 so that coating layer 30 can move independently of core wire 20 when guidewire 10 becomes stuck.

[0040] The tip of the support 36 is located further distal than the tip of the non-fixed portion 52. Also, the base end of the support 36 is located further proximal than the base end of the non-fixed portion 52. That is, at the position in the long axis direction X, the support 36 covers the entire non-fixed portion 52, and the length of the support 36 along the long axis direction X is longer than the length of the non-fixed portion 52. Note that at the position in the long axis direction X, the support 36 may cover only a portion of the non-fixed portion 52.

[0041] The tip of the support 36 is preferably located closer to the proximal end than the tip of the tip fixing part 51. The tip of the support 36 is preferably spaced 30 mm or more away from the tip of the guidewire 10 toward the proximal end. This ensures high flexibility of the tip portion of the guidewire 10.

[0042] When the covering layer 30 has a support 36, the resin forming the resin layer 31 does not need to have high rigidity and tensile strength by itself, and therefore a highly flexible material such as urethane can be used.

[0043] As described above, in the third embodiment, the coating layer 30 includes the support 36 fixed to the resin forming the coating layer 30, and the tip of the support 36 is located distal to the tip of the non-fixed portion 52, and the base end of the support 36 is located proximal to the base end of the non-fixed portion 52. This allows the guidewire 10 to support the entire portion of the coating layer 30 that can move independently of the core wire 20 (non-fixed portion 52) by the support 36, thereby preventing damage to the coating layer 30.

[0044] <Fourth embodiment> The guidewire 10 according to the fourth embodiment differs from the third embodiment in that a support 36 included in the covering layer 30 is in contact with the core wire 20, as shown in FIG.

[0045] In the fourth embodiment, the support 36 included in the covering layer 30 is fixed in close contact with the inner surface of the resin layer 31. Therefore, the support 36 is exposed to the inner surface of the covering layer 30. The inner surface of the tubular support 36 is in slidable contact with the outer surface of the low friction layer 40 fixed to the outer surface of the core wire 20. That is, at least a part of the coil forming the support is exposed radially inward from the inner surface of the resin layer 31 forming the covering layer 30, and is in slidable contact with the outer surface of the low friction layer 40 fixed to the outer surface of the core wire 20. Note that when the guide wire 10 does not have the low friction layer 40, the inner surface of the support 36 is in direct slidable contact with the core wire 20.

[0046] The resin layer 31 partially penetrates into the gaps on the outer surface side of the tubular support 36 from the outer surface side, but does not reach the core wire 20. Therefore, a hollow portion 37 that is not filled with the resin layer 31 is formed between the support 36 and the core wire 20. This reduces the contact area between the coating layer 30 and the core wire 20, thereby reducing frictional resistance and improving slidability. High slidability can be obtained.

[0047] Furthermore, since the support 36 is in contact with the core wire 20, the support 36 and the core wire 20 can move together. As a result, the guidewire 10 has no hollow area through which force escapes when the guidewire 10 is pushed, and therefore has high pushability and torque transmission properties compared to when the support 36 is not in contact with the core wire 20.

[0048] As described above, in the fourth embodiment, the support 36 is exposed on the inner surface of the coating layer 30 at the non-fixed portion 52 and is in slidable contact with the outer surface of the low-friction layer 40 fixed to the outer surface of the core wire 20. As a result, in the guidewire 10, the support 36 of the coating layer 30 contacts the core wire 20 at the non-fixed portion 52, improving the slidability between the coating layer 30 and the outer surface of the core wire 20.

[0049] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. For example, as in a modified example shown in Fig. 5, the coating layer 30 may be disposed only on the distal end of the guidewire 10. Such a guidewire 10 may have a distal end fixed portion 51, a proximal end fixed portion 53, and a non-fixed portion 52 similar to the first to fourth embodiments described above.

[0050] Also, the guidewire 10 does not need to have a layer made of a low-friction material such as the low-friction layer 40. Such a guidewire 10 can be produced, for example, by covering the core wire 20 with a resin tube having heat shrinkability that serves as the resin layer 31, and heating only the distal end and proximal end of the resin tube to heat shrink it. The distal end of the resin tube that has been heat-shrunk is fixed to the core wire 20 to form a distal end fixing portion 51 together with the core wire 20, and the proximal end of the resin tube that has been heat-shrunk is fixed to the core wire 20 to form a proximal end fixing portion 53 together with the core wire 20. The unheated central portion of the resin tube is in slidable contact with the core wire 20, and forms a non-fixed portion 52 together with the core wire 20.

[0051] Furthermore, non-fixed portion 52 does not necessarily have to be formed continuously, and may be divided into a plurality of portions in the longitudinal axis direction X of guidewire 10. For example, non-fixed portion 52 may exist within a range of 100 mm from the tip of non-fixed portion 52 toward the base end, and another fixed portion to which core wire 20 and coating layer 30 different from tip fixed portion 51 and base fixed portion 53 are fixed may exist within a predetermined range on the base end side, and another non-fixed portion 52 may exist within a range of 100 mm from the base end toward the base end.

[0052] In the first to fourth embodiments and modified examples described above, the coating layer 30 and the core wire 20 in the non-fixed portion 52 of the guidewire 10 are in slidable contact with each other over the entirety of the non-fixed portion 52, but only a part of the non-fixed portion 52 may be in slidable contact with each other, and the other part may be fixed. For example, the coating layer 30 and the core wire 20 in the non-fixed portion 52 may be in striped, spiral, striped, or dotted contact with each other. In this case, the part in the non-fixed portion 52 of the guidewire 10 where the coating layer 30 and the core wire 20 are fixed is sandwiched between the parts where the coating layer 30 and the core wire 20 are not fixed, and has a short length along the long axis direction X. Therefore, when torque is applied to the non-fixed portion 52, the coating layer 30 can be easily peeled off from the core wire 20. This makes it possible to precisely determine the slidability of the coating layer 30 and the core wire 20 by the width of the stripes, the pitch of the spiral, or the like, and the guidewire 10 can be adjusted to have a good balance between rigidity and torque transmission.

[0053] Alternatively, a groove, protrusion or step extending in the circumferential direction may be formed on the outer surface of the core wire 20 or the low friction layer 40 located at the non-fixed portion 52 of the guidewire 10, and the inner surface of a member (the coating layer 30 or the low friction layer 40) located at the non-fixed portion 52 and in slidable contact with the outer surface on which the groove, protrusion or step is formed may have a shape that fits into the groove, protrusion or step. This allows the coating layer 30 to directly or indirectly contact the core wire 20 at the non-fixed portion 52 so as to be slidable in the circumferential direction while not sliding in the longitudinal direction X. This allows the guidewire 10 to suppress a change in the outer diameter of the guidewire 10 at the non-fixed portion 52 due to the coating layer 30 sliding in the longitudinal direction X relative to the core wire 20.

[0054] The low-friction layer 40 may be a liquid (fluid) rather than a solid. In this case, the low-friction layer 40 is not fixed to either the core wire 20 or the covering layer 30. For example, a solution containing a silicone resin is applied to the outer surface of the core wire 20, and then the resin layer 31 is extruded to prevent the resin layer 31 from being fixed to the core wire 20. At this time, the low-friction layer 40 made of silicone resin is not fixed to either the core wire 20 or the covering layer 30, and exists as a liquid between the covering layer 30 and the core wire 20. The low-friction layer 40, which is a liquid (fluid), can effectively reduce the frictional resistance between the covering layer 30 and the core wire 20.

[0055] Additionally, the inner surface of covering layer 30 in non-fixed portion 52 may be separated from the outer surface of core wire 20 without contacting it. [Explanation of symbols]

[0056] 10 Guidewire 20 Core Wire 30 Covering layer 31 Resin layer 36 Support 40 Low friction layer 51 Tip fixing part 52 Non-fixed part 53 base end fixing part X major axis direction

Claims

1. A core wire extending in a longitudinal direction from a distal end to a proximal end; a coating layer formed of resin and covering at least a tip portion of the core wire, This guidewire is characterized by having a tip fixed portion in which the coating layer is fixed to the outer surface of the core wire, a non-fixed portion located proximal to the tip fixed portion and in which the coating layer is in direct or indirect contact with the outer surface of the core wire so as to be able to slide along the outer surface of the core wire, and a base end fixed portion located proximal to the non-fixed portion and in which the coating layer is fixed to the outer surface of the core wire.

2. The non-fixed portion has a low friction layer between the coating layer and the core wire, 2. The guidewire of claim 1, wherein the low friction layer is secured to an outer surface of the core wire and in slidable contact with an inner surface of the coating layer.

3. The non-fixed portion has a low friction layer between the coating layer and the core wire, 2. The guidewire of claim 1, wherein the low friction layer is secured to an inner surface of the coating layer and in slidable contact with an outer surface of the core wire.

4. The coating layer includes a support fixed to a resin that forms the coating layer, a tip end of the support is located on the tip side of the tip end of the non-fixed portion, 4. The guidewire according to claim 1, wherein the proximal end of the support is located closer to the proximal end than the proximal end of the non-fixed portion.

5. The guide wire according to claim 4, characterized in that the support is exposed on the inner surface of the coating layer at the non-fixed portion and is in slidable contact with the outer surface of a low friction layer fixed to the outer surface of the core wire.

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