Guide wire

Abstract

The purpose of the present invention is to provide a guide wire that, even if a hydrophilic coating comes into contact with liquids such as bodily fluids, can improve the rotation response of the guide wire while suppressing increases in friction resistance with devices used in combination, the friction resistance accompanying swelling of the hydrophilic coating.　This guide wire 1 is provided with: a core shaft 11; a coil body 21 onto which a wire w is wound so as to cover the outer periphery of a tip section of the core shaft 11; a first part 41 that comprises a hydrophilic coating 411 disposed on a surface, of an outer peripheral surface of the wire w, on the radially outer side, and a hydrophobic coating 412 formed over the hydrophilic coating 411; and a second part 51 that is a part on the radially outer side of the axial center of the wire and comprises a hydrophilic coating 511 that is disposed so as to fill a recessed section between wires w, w that are adjacent in a longitudinal direction.

Description

Guidewire

[0001] The present invention relates to a guidewire.

[0002] For example, when a treatment instrument (combined device) such as a catheter is inserted into a body cavity such as a blood vessel, a guide wire is inserted into the body cavity prior to the insertion of the combined device to guide the combined device to the treatment site.

[0003] For example, the guide wire is inserted into a body cavity after its tip has been shaped into an approximately J-shape. At the point where the body cavity branches, the guide wire is rotated appropriately so that the tip faces the desired branch vessel, and the tip is pushed forward to the site to be treated.

[0004] To enable such guidewires to reach the treatment site quickly, various techniques have been proposed, such as reducing the contact area of ​​the guidewire with the wall surface to reduce frictional resistance with the concomitant device (see, for example, Patent Document 1), or providing a hydrophilic coating on the surface of the guidewire that contacts the wall surface, which absorbs water when it comes into contact with body fluids and forms a liquid film on the outermost surface, thereby reducing frictional resistance with the concomitant device (see, for example, Patent Document 2).

[0005] JP 2011-152211 A JP 2012-70979 A

[0006] However, even when a liquid film is formed on the outermost surface using a hydrophilic coating, if the hydrophilic coating swells too much due to water absorption, the clearance between the outer peripheral surface and the concomitant device that abuts the coating may become small, which may increase the frictional resistance with the concomitant device and result in poor rotational response of the guidewire when the distal end of the guidewire is rotated by hand.

[0007] The present invention was made based on the above circumstances, and its purpose is to provide a guidewire that can improve the rotational response of the guidewire while suppressing the increase in frictional resistance with a concomitant device that occurs due to swelling of the hydrophilic coating, even when the hydrophilic coating comes into contact with liquids such as body fluids.

[0008] Some aspects of the present disclosure include: (1) a guidewire comprising: a core shaft; a coil body in which a wire is wound so as to cover an outer periphery of a tip end of the core shaft; a first section comprising a hydrophilic coating arranged on a surface located radially outward of an outer periphery of the wire and a hydrophobic coating formed on the outer periphery of the hydrophilic coating; and a second section radially outward from an axial center of the wire and comprising a hydrophilic coating arranged so as to fill a recess between adjacent wires along the longitudinal direction; (2) the guidewire according to (1), in which, when the hydrophilic coating is dry, the distance between the outer periphery of the second section and the central axis of the core shaft is smaller than the distance between the outer periphery of the first section and the central axis of the core shaft; (3) the guidewire according to (1), in which, when the hydrophilic coating is in contact with a liquid, the distance between the outer periphery of the second section and the central axis of the core shaft is approximately equal to the distance between the outer periphery of the first section and the central axis of the core shaft; and (4) a core shaft; The guide wire comprises: a coil body in which a wire is wound so as to cover the outer periphery of the tip of the core shaft; a first portion consisting of a hydrophobic coating arranged on a surface of the outer periphery of the wire that is located radially outward; and a second portion consisting of a hydrophilic coating that is located radially outward from the axial center of the wire and that is arranged so as to fill recesses between adjacent wires along the longitudinal direction.

[0009] In this specification, "distal side" refers to the direction along the longitudinal axis of the guidewire, in which the guidewire is inserted deeper (distal) into a body cavity. "Proximal side" refers to the direction along the longitudinal axis of the guidewire, in the opposite direction to the "distal side." "Distal" refers to the distal end of any member or part, and "proximal end" refers to the proximal end of any member or part. "Distal portion" refers to the portion of any member or part that includes the distal end and extends from this distal end to the middle of the longitudinal direction toward the proximal end. "Proximal end" refers to the portion of any member or part that includes the proximal end and extends from this proximal end to the middle of the longitudinal direction toward the distal end. "Longitudinal direction" refers to the longitudinal axis of the core shaft unless otherwise specified. "Radial direction" refers to the radial direction perpendicular to the longitudinal axis of the core shaft.

[0010] The present invention can provide a guidewire that can improve the rotational response of the guidewire while suppressing the increase in frictional resistance with a concomitant device that occurs due to swelling of the hydrophilic coating, even when the hydrophilic coating comes into contact with liquids such as body fluids.

[0011] FIG. 1 is a schematic longitudinal sectional view showing a first embodiment; FIG. 2 is a schematic side view showing an enlarged portion of the first embodiment; FIG. 3 is a schematic longitudinal sectional view showing an enlarged portion of the first embodiment, when the hydrophilic coat is dry; FIG. 4 is a schematic longitudinal sectional view showing an enlarged portion of the first embodiment, when the hydrophilic coat is in contact with a liquid; FIG. 5 is a schematic sectional view showing an example of a state of the guide wire in the first embodiment, when the hydrophilic coat is dry; FIG. 6 is a schematic sectional view showing an example of a state of the guide wire in the first embodiment, when the hydrophilic coat is in contact with a liquid; FIG. 7 is a schematic longitudinal sectional view showing an enlarged portion of the second embodiment, when the hydrophilic coat is dry; FIG. 8 is a schematic longitudinal sectional view showing an enlarged portion of the second embodiment, when the hydrophilic coat is in contact with a liquid;

[0012] The guide wire of the present disclosure comprises a core shaft, a coil body in which a wire is wound so as to cover the outer periphery of the tip of the core shaft, a first portion consisting of a hydrophilic coating arranged on a radially outer surface of the outer periphery of the wire, and a hydrophobic coating formed on the outer periphery of the hydrophilic coating, and a second portion located radially outward from the axial center of the wire and consisting of a hydrophilic coating arranged so as to fill recesses between adjacent wires along the longitudinal direction.

[0013] The present disclosure includes a guide wire comprising: a core shaft; a coil body in which a wire is wound to cover the outer periphery of the tip of the core shaft; a first portion consisting of a hydrophobic coating arranged on a radially outer surface of the outer periphery of the wire; and a second portion consisting of a hydrophilic coating arranged radially outward from the axial center of the wire so as to fill recesses between adjacent wires along the longitudinal direction.

[0014] Note that rotational response refers to the ease with which the distal end of the guidewire initiates rotational behavior in response to a rotational operation at the proximal end of the guidewire, and torque transmittance refers to the ability to transmit a rotational force applied to the proximal end of the guidewire to the distal end of the guidewire.

[0015] Hereinafter, first and second embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments shown in the drawings. Furthermore, the dimensions of each part shown in the drawings are shown to facilitate understanding of the implementation content and do not necessarily correspond to the actual dimensions.

[0016] 1 to 8C, the left side of the figure is the tip side (distal side) that is inserted deeper (distal) into the body cavity, and the right side of the figure is the base side (hand side, proximal side).

[0017] 1 to 4 are schematic diagrams showing a first embodiment. As shown in Fig. 1 and Fig. 2, the guidewire 1 is generally composed of a core shaft 11, a coil body 21, a tip fixation portion 31, a first section 41, and a second section 51. Fig. 3 shows the guidewire 1 in a state where it is not in contact with a liquid (a state where the hydrophilic coatings 411, 511 are dry), and Fig. 4 shows the guidewire 1 in a state where it is in contact with a liquid (a state where the hydrophilic coatings 411, 511 are in contact with a liquid).

[0018] The core shaft 11 is a longitudinal member that forms the axial core of the guide wire 1. The core shaft 11 is formed, for example, from a flexible material, and can be configured so that the distal end portion thereof gradually tapers in diameter toward the distal end.

[0019] In this embodiment, the tip end portion of the core shaft 11 is configured to have a small diameter portion 111 having a constant outer diameter, a large diameter portion 113 located closer to the base end than the small diameter portion 111 and having a constant outer diameter larger than the small diameter portion 111, and a tapered portion 112 arranged to be continuous with the small diameter portion 111 and the large diameter portion 113 and gradually increasing in diameter from the small diameter portion 111 toward the large diameter portion 113. In other words, when the core shaft 11 extends linearly, the small diameter portion 111 and the large diameter portion 113 each have a cylindrical shape with a constant outer diameter, and the tapered portion 112 has a truncated cone shape that gradually increases in diameter toward the base end.

[0020] Although not shown, the core shaft 11 may further have a truncated cone-shaped connecting portion whose tip is continuous with the base end of the large diameter portion 113, or a cylindrical main body portion with a constant outer diameter whose tip is continuous with the base end of the connecting portion.

[0021] It is preferable that the material constituting the core shaft 11 has flexibility, antithrombogenicity, and biocompatibility. Examples of such materials include stainless steel such as SUS304, and superelastic alloys such as Ni-Ti alloys.

[0022] The coil body 21 is a spiral (coil-shaped) member in which a wire is wound so as to cover the outer periphery of the tip end of the core shaft 11. Specifically, the coil body 21 can be formed by winding a single or multiple strands of wire w so as to cover at least a portion of the core shaft 11. The coil body 21 may be loosely wound with gaps between the wires along the longitudinal direction, or tightly wound with the wires in contact with each other.

[0023] One or more solid wires, or one or more twisted wires, can be used as the wires w that make up the coil body 21. Here, a solid wire refers to one single wire, and a twisted wire refers to a bundle of wires formed by twisting multiple single wires together in advance.

[0024] The wire material constituting the coil body 21 can be, for example, stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; or radiopaque metals such as platinum and tungsten, from the viewpoint of ensuring the flexibility of the guide wire 1 and imparting antithrombogenicity and biocompatibility.

[0025] The tip fixing portion 31 is a portion where the tip of the core shaft 11 and the tip of the coil body 21 are integrally fixed. Specifically, the tip fixing portion 31 can be formed, for example, so that the tip portion has a generally hemispherical shape that is convexly curved toward the tip side. This reduces resistance when the guidewire 1 advances inside the body cavity, allowing the guidewire 1 to be inserted smoothly.

[0026] The tip fixing portion 31 can be formed, for example, by melting and molding a part of the members constituting the core shaft 11 and / or the coil body 21, or by joining the core shaft 11 and the coil body 21 using a brazing material and molding the brazing material. Examples of the brazing material include metal brazing materials such as Sn—Pb alloy, Pb—Ag alloy, Sn—Ag alloy, and Au—Sn alloy.

[0027] The base end of the coil body 21 can be joined to the core shaft 11. Specifically, for example, the base end of the coil body 21 may be joined to the outer peripheral surface of the core shaft 11 (for example, the outer peripheral surface of the large diameter portion 113) using a brazing material. Examples of the brazing material used to join the base end of the coil body 21 include brazing materials similar to the brazing material used to form the tip fixing portion.

[0028] The first portion 41 is composed of a hydrophilic coating disposed on the radially outer surface of the outer periphery of the wire w, and a hydrophobic coating formed on the outer periphery of the hydrophilic coating. Specifically, as shown in Figures 2 and 3, the first portion 41 is provided on the outer periphery of the coil body 21, i.e., on the surface of the wire w located radially outward from the center of the wire w. The first portion 41 is layered in the following order from the wire w side: hydrophilic coating 411 and hydrophobic coating 412. Note that the static friction coefficients of the surfaces when in contact with a liquid increase in the order of hydrophilic coating < hydrophobic coating < wire.

[0029] For example, when the guide wire 1 is inserted into a body cavity, the hydrophilic coating 411 improves the slipperiness (reducing frictional resistance) between the surface of the guide wire 1 and the wall of the body cavity, and between the surface of the guide wire 1 and a companion device (not shown) through which the guide wire 1 is inserted.

[0030] Examples of materials that can be used to form the hydrophilic coating 411 include polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, polyacrylic acid, sodium polyacrylate, poly(2-hydroxyethyl methacrylate), maleic anhydride copolymers, ethylene-vinyl alcohol copolymers, 2-methacryloyloxyethyl phosphorylcholine or its copolymers, (2-hydroxyethyl methacrylate)-styrene block copolymers, various synthetic polypeptides, collagen, hyaluronic acid, cellulose-based polymers, and mixtures thereof. The hydrophilic coating 411 may also contain additives such as crosslinkers, non-volatile solvents, volatile solvents, and surfactants.

[0031] The hydrophobic coating 412, for example, limits the amount of liquid that penetrates deep into the first portion 41. This hydrophobic coating 412 prevents the liquid from reaching the hydrophilic coating 411 located deep in the first portion 41, and can reduce excessive swelling of the hydrophilic coating 411 due to the penetrated liquid.

[0032] Examples of materials that can be used to form the hydrophobic coating 412 include silicone, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), and mixtures thereof. The hydrophobic coating 412 may also contain additives such as a cross-linking agent, a non-volatile solvent, a volatile solvent, and a surfactant.

[0033] The second portion 51 is a portion radially outward from the axial center of the wire w and is made of a hydrophilic coating arranged to fill recesses between adjacent wires w along the longitudinal axis. Specifically, as shown in Figures 2 and 3, the second portion 51 is arranged on the outer circumferential surface side of the coil body 21, i.e., to fill recesses (valleys) between adjacent wires w, w located radially outward from the axial center of the wire w.

[0034] In addition, the hydrophilic coating 511 in the second portion 51 also improves (reduces frictional resistance) the slipperiness between the surface of the guidewire 1 and the wall of the body cavity, and between the surface of the guidewire 1 and a concomitant device through which the guidewire 1 is inserted, for example, when the guidewire 1 is inserted into a body cavity.

[0035] Examples of materials constituting the hydrophilic coating 511 in the second region 51 include materials similar to those constituting the above-described hydrophilic coating 411. The material constituting the hydrophilic coating 511 may be the same as or different from the material constituting the hydrophilic coating 411.

[0036] Here, we will explain the state of the first and second portions 41, 51 when the guide wire 1 is not in contact with liquid (the state when the hydrophilic coatings 411, 511 are dry), and the state of the first and second portions 41, 51 when the guide wire 1 is in contact with liquid (the state when the hydrophilic coatings 411, 511 are in contact with liquid).

[0037] Fig. 3 is a schematic diagram of the hydrophilic coatings 411, 511 when they are dry, and Fig. 4 is a schematic diagram of the hydrophilic coatings 411, 511 when they are in contact with a liquid. For example, when the guidewire 1 is inserted into a body cavity and comes into contact with surrounding liquid such as a body fluid, the liquid penetrates into the hydrophilic coating 411 at the first portion 41 through the hydrophobic coating 412 located on the surface. When the liquid penetrates to the hydrophilic coating 411, the hydrophilic coating 411 absorbs the liquid, and a liquid film (not shown) is formed on the surface side (radially outward) of the hydrophilic coating 411. The volume of the formed liquid film expands due to the absorbed liquid, and the formed liquid film exhibits viscosity.

[0038] In this case, if there is no hydrophobic coating and the hydrophilic coating is exposed on the surface, the hydrophilic coating will absorb body fluids and swell, reducing the clearance between the guidewire and the inner wall of the combined device through which the guidewire is inserted. Therefore, even if a liquid film is formed, it will actually increase the frictional resistance between the guidewire and the combined device, hindering smooth operation of the combined device.

[0039] 4, in the first region 41, the hydrophobic coating 412 is laminated on the hydrophilic coating 411, and this hydrophobic coating 412 limits the amount of liquid that penetrates the hydrophilic coating 411 located deep within the first region 41. As a result, swelling of the hydrophilic coating 411 is suppressed, and a clearance is secured between the guidewire 1 and the inner wall of the combination device, thereby reducing the frictional resistance between the guidewire 1 and the combination device.

[0040] On the other hand, the second region 51 does not have a hydrophobic coating, and the hydrophilic coating 511 is exposed on the surface. Therefore, when the guidewire 1 comes into contact with a liquid, more liquid penetrates the hydrophilic coating 511 since there is no hydrophobic coating on the surface, and the hydrophilic coating 511 swells in accordance with the amount of liquid absorbed. As a result, the outer peripheral surface s2 of the second region 51 located in the valleys between adjacent wires w bulges outward in the radial direction, and the liquid film on the bulging surface reduces the frictional resistance between the guidewire 1 and the combined device.

[0041] There is no particular limitation on the ratio of the area of ​​the first portion 41 to the area of ​​the second portion 51 on the outermost surface of the guide wire 1 when dry. The ratio of the surface area of ​​the first portion 41 to the surface area of ​​the second portion 51 may be set to, for example, 1:10 to 10:1.

[0042] The thickness of the hydrophilic coating 411 and the hydrophobic coating 412 of the first region 41 when dried is not particularly limited as long as it does not impair the effects of the present invention. The thickness of each of the hydrophilic coating 411 and the hydrophobic coating 412 of the first region 41 may be set to, for example, 1 μm to 300 μm.

[0043] The radial thickness of the hydrophilic coating 511 of the second region 51 when dry is not particularly limited as long as it does not impair the effects of the present invention. The thickness of the hydrophilic coating 511 of the second region 51 may be set to, for example, 1 μm to 300 μm.

[0044] 5A , when the hydrophilic coatings 411, 511 are dry, the distance L2 between the outer peripheral surface s2 of the second portion 51 and the central axis x of the core shaft 11 is preferably smaller than the distance L1 between the outer peripheral surface s1 of the first portion 41 and the central axis x of the core shaft 11. This makes it possible to prevent the second portion 51 from protruding radially outward from the first portion 41, even when the hydrophilic coating 511 of the second portion 51 is in contact with a liquid, and together with the formation of a liquid film, it is possible to further reduce the frictional resistance between the second portion 51 and the combination device in contact with the second portion 51.

[0045] 5B , when the hydrophilic coatings 411, 511 are in contact with a liquid, it is also preferable that the distance L2 between the outer peripheral surface s2 of the second portion 51 and the central axis x of the core shaft 11 is approximately equal to the distance L1 between the outer peripheral surface s1 of the first portion 41 and the central axis x of the core shaft 11. This reduces the unevenness between the outer peripheral surfaces s1, s2 of the first and second portions 41, 51 when the hydrophilic coatings 511 of the second portion 51 are in contact with a liquid, thereby improving the slipperiness between the second portion 51 and the combination device.

[0046] Next, a description will be given of a mode of use of the guidewire 1. Here, an example will be given of a procedure for inserting the guidewire 1 into a blood vessel.

[0047] First, in order to improve blood vessel selectivity by the rotation operation, the distal end of the guide wire 1 is bent in advance into a J-shape or the like as necessary before inserting the guide wire 1 into a blood vessel.

[0048] Next, the guidewire 1 is inserted into the blood vessel from its tip, and the proximal end of the guidewire 1 exposed outside the body is manipulated to push the tip forward. At the branching point of the blood vessel, the guidewire 1 is rotated so that the tip of the guidewire 1 faces the desired blood vessel. At this time, the excellent rotational response allows the guidewire 1 to be easily rotated.

[0049] Next, after the distal end of the guidewire 1 reaches the treatment site, the proximal end of the guidewire 1 is inserted into the lumen of a combined device (not shown) such as a catheter from its distal end, and the combined device is advanced within the blood vessel along the guidewire 1. Next, after the combined device reaches the treatment site, various treatments are performed using the combined device. Next, after the treatment is completed, the combined device and guidewire 1 are withdrawn from the blood vessel, completing the series of procedures.

[0050] As described above, the guidewire 1 has the above-described configuration, and therefore, even when the hydrophilic coating 411 comes into contact with a liquid such as a body fluid, the rotational response of the guidewire 1 can be improved while suppressing an increase in frictional resistance (particularly, static friction coefficient) with the concomitant device that accompanies swelling of the hydrophilic coating 411. Furthermore, since the frictional resistance with the concomitant device is improved, torque transmission can also be improved.

[0051] The following reasons are presumed to be responsible for the improved rotational response and torque transmissibility: In the first region 41, the presence of the hydrophobic coating 412 limits the penetration of bodily fluid that comes into contact with the surface of the first region 41. Therefore, bodily fluid that has moderately penetrated into the hydrophilic coating 411 forms a liquid film that covers a portion of the outermost surface of the first region 41 (the surface that contacts the combination device), while suppressing swelling of the hydrophilic coating 411 located directly below the hydrophobic coating 412. As a result, an increase in frictional resistance with the combination device due to swelling of the hydrophilic coating 411 is suppressed, and this, combined with the formation of the liquid film, is presumed to improve the rotational response and torque transmissibility of the guidewire 1.

[0052] Although not shown in Figure 4, when the first portion 41 is in contact with a liquid, a part of the hydrophilic coating 411 that was located directly below the hydrophobic coating 412 when it was dried may seep onto the hydrophobic coating 412, forming a liquid film on its outermost surface (the surface of the guide wire that contacts the combination device), or the hydrophilic coating 411 may remain directly below the hydrophobic coating 412, forming a liquid film that covers part of the outermost surface.

[0053] Second Embodiment Figures 6 and 7 are enlarged, schematic longitudinal cross-sectional views of a portion (part of a coil body) of a second embodiment. The guidewire 2 is generally composed of a first section 42, a core shaft 11 (not shown), a coil body 21, a tip fixation portion 31 (not shown), and a second section 51. Figure 6 illustrates the guidewire 2 in a state where it is not in contact with a liquid (a state where the hydrophilic coating 511 is dry), and Figure 7 illustrates the guidewire 2 in a state where it is in contact with a liquid (a state where the hydrophilic coating 511 is in contact with a liquid). The guidewire 2 differs from the first embodiment in the configuration of the first section 42. The configurations of the core shaft 11, the coil body 21, the tip fixation portion 31, and the second section 51, as well as the configuration of the first section 42 described below, are similar to those of the first embodiment. Therefore, the same reference numerals are used to designate the same components, and detailed descriptions thereof will be omitted. The use of the guidewire 2 is also exemplified as in the first embodiment.

[0054] The first portion 42 is a portion made of a hydrophobic coating disposed on a radially outer surface of the outer circumferential surface of the wire w. Specifically, as shown in Fig. 6, the first portion 42 is provided on the outer circumferential surface side of the coil body 21, i.e., on the surface of the wire w located radially outward from the center of the wire w.

[0055] In the first section 42 of this embodiment, only the hydrophobic coating 422 is disposed on the radially outer surface of the wire w. This hydrophobic coating 422 reduces the frictional resistance with the combination device, for example, compared to when the wire w and the combination device are in direct contact. In other words, the static friction coefficients of the surfaces when in contact with a liquid are such that the hydrophobic coating is smaller than the wire.

[0056] The material constituting the hydrophobic coating 422 may be, for example, the same as the material of the hydrophobic coating 412 exemplified in the first embodiment.

[0057] Here, we will explain the state of the first and second regions 42, 51 when the guide wire 2 is not in contact with liquid (the state when the hydrophilic coating 511 is dry), and the state of the first and second regions 42, 51 when the guide wire 2 is in contact with liquid (the state when the hydrophilic coating 511 is in contact with liquid).

[0058] For example, when the guidewire 2 is inserted into a body cavity and comes into contact with surrounding liquids such as bodily fluids, the hydrophobic coating 422 comes into contact with the bodily fluids at the first region 42. This hydrophobic coating 422 does not easily absorb bodily fluids, and swelling of the hydrophobic coating 422 itself is negligibly small, so that the clearance between the guidewire 2 and the inner wall of the combination device is maintained, and an increase in frictional resistance between the guidewire 2 and the combination device is suppressed.

[0059] On the other hand, the second region 51 does not have a hydrophobic coating, but has a hydrophilic coating 511 disposed on its surface. Therefore, when the hydrophilic coating 511 of the second region 51 comes into contact with a liquid, the liquid penetrates the hydrophilic coating 511 without hindrance, and the hydrophilic coating 511 swells with the large amount of liquid absorbed, as shown in Fig. 7. As a result, the outer peripheral surface s2 of the second region 51, which is made of the hydrophilic coating 511 disposed so as to fill the gaps between adjacent wires w along the longitudinal direction, swells outward in the radial direction, reducing unevenness with the outer peripheral surface s1, and the liquid film formed on the surface of the second region 51 reduces frictional resistance between the guidewire 2 and the combined device.

[0060] As described above, since the guidewire 2 has the above-described configuration, even if the hydrophilic coating 511 comes into contact with a liquid such as a body fluid, the first portion 42 does not swell excessively because there is no hydrophilic coating directly below the hydrophobic coating 422, and the hydrophobic coating 422, whose surface friction coefficient is smaller than that of the wires w, can improve the rotational response of the guidewire 2. Furthermore, since the frictional resistance with the combined device is improved, torque transmission can also be improved.

[0061] The present disclosure is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the scope and meaning equivalent to the claims, as defined by the claims. Part of the configurations of the above-described embodiments may be deleted or replaced with other configurations, or other configurations may be added to the configurations of the above-described embodiments.

[0062] For example, in the above-described embodiment, when the guidewires 1 and 2 are in contact with a liquid, the distance L2 between the outer circumferential surface s2 of the second portion 51 and the central axis x of the core shaft 11 is approximately equal to the distance L1 between the outer circumferential surface s1 of the first portion 41 and 42 and the central axis x of the core shaft 11. However, the degree to which the second portion 41 and 42 swells due to the contact with the liquid is not particularly limited. When the guidewires 1 and 2 are in contact with a liquid, for example, L2<L1 may be satisfied (see second portion 52A in FIG. 8A ) or L2>L1 may be satisfied (see second portion 52B in FIG. 8B ).

[0063] Furthermore, when the guidewire is in contact with a liquid, the cross-sectional shape of the outer surface of the bulging hydrophilic coating in the second region is not limited to a substantially linear shape (see Figures 4 and 7), and may be, for example, a rounded shape (see second region 52C in Figure 8C).

[0064] In the above-described embodiments, the guidewires 1 and 2 are described in which the hydrophilic coating 411, 511 or the hydrophobic coating 412, 422 is provided only on the radially outer side of the outer circumferential surface of the wire w. However, the hydrophilic coating or the hydrophobic coating may also be provided on the radially inner side of the outer circumferential surface of the wire w.

[0065] In the above-described embodiments, the guidewires 1 and 2 are described as having a coil body 21 in which the wires w are tightly wound along the entire longitudinal direction. However, the guidewire may also have a coil body in which at least a portion of the longitudinal direction is loosely wound. In a loosely wound coil body, for example, adjacent spaced apart wires may be connected (bridged) via the hydrophilic coating in the second portion in a cross-sectional view of the guidewire cut along the longitudinal direction.

[0066] 1, 2 Guide wire 11 Core shaft 21 Coil body 41, 42 First portion 411 Hydrophilic coating 412, 422 Hydrophobic coating 51 Second portion 511 Hydrophilic coating L1, L2 Distance s1, s2 Outer circumferential surface w Wire

Claims

1. A guide wire comprising: a core shaft; a coil body in which a strand of wire is wound to cover the outer periphery of the tip of the core shaft; a first portion consisting of a hydrophilic coating arranged on a radially outer surface of the outer periphery of the strand of wire and a hydrophobic coating formed on the outer periphery of the hydrophilic coating; and a second portion consisting of a hydrophilic coating arranged radially outward from the axial center of the strand of wire so as to fill recesses between adjacent strands of wire along the longitudinal direction.

2. The guidewire of claim 1, wherein when the hydrophilic coating is dry, the distance between the outer surface of the second portion and the central axis of the core shaft is smaller than the distance between the outer surface of the first portion and the central axis of the core shaft.

3. The guide wire of claim 1, wherein when the hydrophilic coating is in contact with a liquid, the distance between the outer surface of the second portion and the central axis of the core shaft is approximately equal to the distance between the outer surface of the first portion and the central axis of the core shaft.

4. A guide wire comprising: a core shaft; a coil body in which a wire is wound to cover the outer periphery of the tip of the core shaft; a first portion consisting of a hydrophobic coating arranged on a radially outer surface of the outer periphery of the wire; and a second portion consisting of a hydrophilic coating arranged radially outwardly of the axial center of the wire so as to fill recesses between adjacent wires along the longitudinal direction.

Images