guide wire

Abstract

The present application gives consideration to lubricity of the guide wire and passability of the combined device in high dimension. The guide wire has a core shaft, a coil body in which a wire is spirally wound around the outer periphery of the core shaft, and a coating layer provided on the outer periphery of the coil body. The coating layer is configured to have a mountain portion that protrudes in the outer peripheral direction of the guide wire in a swollen state. In a cross section including a central axis of the coil body, an apex of the mountain portion is present at a position on the base end side of a first imaginary straight line that passes through a center point of one cross section of the wire and is perpendicular to the central axis, and is present at a position on the tip end side of a second imaginary straight line that passes through a center point of another cross section of the wire adjacent to the one cross section on the base end side with respect to the one cross section and is perpendicular to the central axis.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a guidewire. Background Technology

[0002] A guidewire is used to guide medical devices such as catheters (hereinafter referred to as "combined devices") to a predetermined location inside the human body. The guidewire has a mandrel and a coil body with wire spirally wound around the mandrel.

[0003] To improve the lubrication of the guidewire, a hydrophilic coating is applied to the outer periphery of the coil body. The coating absorbs moisture and swells within the body. When the co-conducting device, guided by the guidewire, is pressed against the coating, the coating is flattened and its surface becomes smooth. Moisture seeps out from the coating, forming a thin film of moisture between the smooth surface of the coating and the co-conducting device. As a result, lubrication between the guidewire and the co-conducting device is ensured.

[0004] In the past, in order to improve the lubricity of medical devices, a technique is known to make the surface of the coating covering the substrate layer into an uneven shape (for example, see Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-146504 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In conventional guidewires, if a connecting device is pressed against the coating, the coating is flattened, and the connecting device comes into contact with the coil wire, potentially reducing the guidewire's lubricity. As with the prior art described above, simply making the coating surface uneven, without considering its positional relationship with the coil, cannot prevent contact between the connecting device and the coil wire, and the guidewire's lubricity may still decrease. Furthermore, increasing the coating thickness is considered to avoid contact between the connecting device and the coil wire; however, simply increasing the coating thickness results in an excessively thick coating during swelling, potentially worsening the passage of the connecting device. Therefore, there is room for improvement in conventional guidewires in balancing lubricity and the passage of the connecting device.

[0010] This specification discloses a technique that can solve the above-mentioned problems.

[0011] Solution for solving the problem

[0012] The techniques disclosed in this specification can be implemented, for example, in the following ways.

[0013] (1) The first guidewire disclosed in this specification comprises a mandrel, a coil body around which wire is spirally wound in a spiral shape, and a coating disposed on the outer periphery of the coil body. The coating is configured to have a ridge protruding toward the outer periphery of the guidewire in a swollen state. In a cross-section including the central axis of the coil body, the apex of the ridge is located at a position closer to the base end than a first imaginary straight line passing through the center point of one cross-section of the wire and perpendicular to the central axis, and at a position closer to the front end than a second imaginary straight line passing through the center point of another cross-section of the wire adjacent to the base end of the one cross-section and perpendicular to the central axis.

[0014] Thus, in this guidewire, the coating is configured with a ridge protruding in the circumferential direction of the guidewire in a swollen state. Therefore, the ridge in the coating effectively retains water and imparts high lubricity to the guidewire. Furthermore, in this guidewire, in a cross-section containing the central axis of the coil body, the apex of the ridge in the swollen state of the coating exists at a position closer to the base end than a first imaginary line perpendicular to the central axis and passing through the center point of one cross-section of the wire, and at a position closer to the front end than a second imaginary line perpendicular to the central axis and passing through the center point of another cross-section of the wire adjacent to that cross-section at the base end. That is, the apex of the ridge in the swollen state of the coating is located between the wires of the coil body. The portion of the coating located between the wires is a portion with a larger "clearance" when subjected to stress from the outer periphery due to the smaller presence of the base wire. Therefore, if the apex of the ridge exists in this portion of the coating, stress from the connecting device can be dispersed. Therefore, according to this guidewire, even if the coating is flattened, contact between the connecting device and the wires of the coil body can be effectively suppressed. Furthermore, the portion of the coating located between the wires is relatively small and easily movable due to the presence of the base wires. Therefore, even if the apex of the coating's peak is located between the wires of the coil body, good passability for concurrent devices can be maintained. In summary, this guidewire achieves a high degree of balance between lubrication and the passability for concurrent devices.

[0015] (2) In the above-described guide wire, it may also be configured such that, in the cross-section containing the central axis of the coil body, the apex of the hill exists in a position that does not overlap with the cross-section of the wire in a direction perpendicular to the central axis. The portion of the coating that does not overlap with the cross-section of the wire of the coil body in a direction perpendicular to the central axis is due to the very small presence of the wire as a base, resulting in a very large "playback" when subjected to stress from the outer periphery. Therefore, if the apex of the hill exists in this portion of the coating, the stress from the co-working device can be effectively dispersed. Therefore, according to this guide wire, even if the coating is flattened, contact between the co-working device and the wire of the coil body can be effectively suppressed.

[0016] (3) The second guidewire disclosed in this specification comprises a mandrel, a coil body around which wire is spirally wound in a spiral shape, and a coating disposed on the outer periphery of the coil body. The coating comprises a first coating disposed on the outer periphery of the coil body and a second coating disposed on the outer periphery of the first coating and having a higher swelling capacity than the first coating. In a cross-section including the central axis of the coil body, the thickness of the second coating on the perpendicular bisecting line of an imaginary line segment connecting a first center point (which is the center point of one cross-section of the wire) and a second center point (which is the center point of another cross-section of the wire adjacent to the base end side of the one cross-section) is greater than the thickness of the second coating on a first imaginary straight line passing through the first center point and perpendicular to the central axis, and is also greater than the thickness of the second coating on a second imaginary straight line passing through the second center point and perpendicular to the central axis.

[0017] Thus, in this guidewire, in a cross-section containing the central axis of the coil body, the thickness of the second coating is greater than that on the perpendicular bisecting line of an imaginary line segment connecting the first center point (which is the center point of one cross-section) and the second center point (which is the center point of another cross-section) of the wire adjacent to that cross-section on the base end side. Therefore, according to this guidewire, a structure can be achieved where the apex of the coating in the swollen body is located at a position closer to the base end side than the first imaginary line and closer to the front end side than the second imaginary line. Therefore, according to this guidewire, lubrication and the passability of the accompanying equipment can be balanced in a high degree.

[0018] (4) In the above-described guidewire, the thickness of the second coating on the perpendicular bisecting line in the cross-section including the central axis of the coil body is at least 1.2 times the thickness of the second coating on the first imaginary straight line, and at least 1.2 times the thickness of the second coating on the second imaginary straight line. According to this guidewire, in the coating of the swollen body, a structure can be achieved where the thickness of the portion located between the wires of the coil body is proportionally greater than the thickness of the portion directly above the wires, further enhancing both lubricity and the passability of the connected equipment.

[0019] Furthermore, the technology disclosed in this specification can be implemented in various ways, such as by means of guidewires, their manufacturing methods, etc. Attached Figure Description

[0020] Figure 1 This is an explanatory diagram that schematically shows the structure of the guide wire 100 in this embodiment.

[0021] Figure 2 This is an explanatory diagram showing the detailed structure of the coating 30 in this embodiment.

[0022] Figure 3 This is an explanatory diagram showing the detailed structure of the coating 30 in this embodiment.

[0023] Figure 4 This is an explanatory diagram showing the state of the guide wire 100 in use according to this embodiment.

[0024] Figure 5 This is an explanatory diagram showing the structure of the coating 30X in the guide wire 100X of the comparative example.

[0025] Figure 6 This is an explanatory diagram showing the structure of the coating 30X in the guide wire 100X of the comparative example.

[0026] Figure 7 This is an explanatory diagram showing the state of the guidewire 100X in use as a comparative example.

[0027] Figure 8 This is an explanatory diagram showing the measurement results of the swelling film thickness of the guide wire 100 in Example 1. Detailed Implementation

[0028] A. Implementation method:

[0029] A-1. Structure of guidewire 100:

[0030] Figure 1 This is an explanatory diagram that schematically shows the structure of the guide wire 100 in this embodiment. Figure 1 This describes the structure of the guide wire 100 (and the mandrel 10 and coil body 20 described later) with a longitudinal section (YZ section) including the central axis AX. Additionally, in Figure 1 The illustration of guidewire 100 is omitted in the text. Figure 1 In this procedure, the positive Z-axis side is the distal end (distal side) of the insertion site, while the negative Z-axis side is the proximal end (proximal side) operated on by the surgeon. Figure 1 The diagram shows the guidewire 100 as a straight line generally parallel to the Z-axis, but at least a portion of the guidewire 100 has a degree of flexibility capable of bending. Furthermore, in this specification, regarding the guidewire 100 and its constituent parts, the end on the front end side is referred to as the "front end," the front end and its vicinity as the "front end portion," the end on the base end side is referred to as the "base end," and the base end and its vicinity as the "base end portion." The cross-sectional structure of each part of the guidewire 100 can be observed, for example, using a laser microscope.

[0031] The guidewire 100 is a long, thin medical device inserted into the human body to guide catheters or other instruments to a predetermined location within the body. The total length of the guidewire 100 is, for example, approximately 1500 mm to 3200 mm.

[0032] The guide wire 100 includes a spindle 10, a coil body 20, a coating 30, a front end side joint 51, a base end side joint 56, and an intermediate fixing part 61.

[0033] The mandrel 10 is an elongated component extending along the central axis AX. From the front end to the base end, the mandrel 10 sequentially comprises a narrow diameter portion 11, a first tapered portion 12, a first large diameter portion 13, a second tapered portion 14, and a second large diameter portion 15. The narrow diameter portion 11 is located at the very front end of the mandrel 10 and is the portion with the smallest outer diameter. The first tapered portion 12 is located between the narrow diameter portion 11 and the first large diameter portion 13, and is a tapered portion whose outer diameter expands from the front end to the base end. The first large diameter portion 13 is located between the first tapered portion 12 and the second tapered portion 14, and has an outer diameter larger than that of the narrow diameter portion 11. The second tapered portion 14 is located between the first large diameter portion 13 and the second large diameter portion 15, and is a tapered portion whose outer diameter expands from the front end to the base end. The second large diameter portion 15 is located at the very base end of the mandrel 10 and is the portion with the largest outer diameter. The second large diameter portion 15 is the portion held by the surgeon or other operator. The shape of the cross-section (XY section) at each location of the mandrel 10 can be any shape, such as circular or flat. In addition, the diameter and length of each part of the mandrel 10 can be arbitrarily set.

[0034] The mandrel 10 may be made of, for example, stainless steel (SUS302, SUS304, SUS316, etc.), Ni-Ti alloy, piano wire, nickel-chromium alloy, cobalt alloy, tungsten, etc. Alternatively, the mandrel 10 may also be made of other hyperelastic alloys or linear hysteresis alloys.

[0035] The coil body 20 is a hollow cylindrical coil-shaped component formed by winding the wire 21 into a spiral shape and extending along the central axis AX. The coil body 20 is disposed on the outer periphery of the mandrel 10 in such a way that it covers the mandrel 10. In this embodiment, the coil body 20 covers the narrow diameter portion 11, the first tapered portion 12, and the first wide diameter portion 13 of the mandrel 10. The wire 21 constituting the coil body 20 can be a single wire or a stranded wire formed by twisting multiple wires together. When the wire 21 is a single wire, the coil body 20 is configured as a single coil; when the wire 21 is a stranded wire, the coil body 20 is configured as a hollow stranded coil. Alternatively, a combination of a single coil and a hollow stranded coil can be used to construct the coil body 20. The wire diameter of the wire 21 and the average diameter of the coil body 20 (the average diameter of the outer diameter and the inner diameter of the coil body 20) can be arbitrarily set. Preferably, the coil body 20 has sparsely wound coils spaced apart between axially adjacent wires 21. However, the coil body 20 can also be a tightly wound coil in which adjacent wires 21 in the axial direction are close to each other.

[0036] The wire 21 constituting the coil body 20 may be formed from materials that are radiolucent, such as stainless steel (SUS302, SUS304, SUS316, etc.), Ni-Ti alloy, or piano wire, or materials that are radiolucent, such as platinum, gold, tungsten, cobalt alloys, nickel-chromium alloys, or alloys thereof. Alternatively, the wire 21 constituting the coil body 20 may also be formed from other hyperelastic alloys or linear hysteresis alloys.

[0037] The front-end joint 51 is a component that joins the front end of the coil body 20 to the front end (narrow diameter portion 11) of the mandrel 10. The base-end joint 56 is a component that joins the base end of the coil body 20 to the mandrel 10 (first thick diameter portion 13). The intermediate fixing portion 61 is a component that joins the coil body 20 to the mandrel 10 (first thick diameter portion 13) near the middle portion along the central axis AX direction of the coil body 20. The front-end joint 51, the base-end joint 56, and the intermediate fixing portion 61 are formed, for example, of metal solder (Au-Sn alloy, Sn-Ag alloy, Sn-Pb alloy, Pb-Ag alloy, etc.), solder (aluminum alloy solder, silver solder, gold solder, etc.), and adhesive (epoxy adhesive, etc.). The materials used to form the front-end joint 51, the base-end joint 56, and the intermediate fixing portion 61 can be the same or different from each other.

[0038] The coating 30 is a hydrophilic resin layer disposed on the outer periphery of the coil body 20. The coating 30 covers at least the outer peripheral surface (outer surface) of the coil body 20. Furthermore, in this embodiment, the coating 30 also covers the surface of the front end side of the front end joint 51 and the surface of the base end side of the base end joint 56. Additionally, the coating 30 may also cover at least a portion of the surfaces of the second tapered portion 14 and the second coarse-diameter portion 15 of the mandrel 10. The coating 30 swells by absorbing moisture within the body, thereby improving the lubricity of the guidewire 100.

[0039] A-2. Detailed structure of coating 30:

[0040] Next, the structure of coating 30 will be described in further detail. Figure 2 and Figure 3 This is an explanatory diagram showing the detailed structure of the coating 30 in this embodiment. Figure 2 and Figure 3 Enlarged view Figure 1 The structure of the longitudinal section (YZ section) of the coating 30 in part X1. Additionally, in Figure 2 and Figure 3 The cross-section shown illustrates multiple cross-sections of the wire 21 that constitutes the coil body 20. Figure 2 The structure of coating 30 (hereinafter also referred to as "coating 30d") in its normal state (dry state) is shown. Figure 3The structure of coating 30 (hereinafter also referred to as "coating 30w") in a swollen state is shown. In this specification, the swollen state refers to the state in which coating 30 is immersed in physiological saline for more than 10 seconds.

[0041] like Figure 2 and Figure 3 As shown, coating 30 has a two-layer structure consisting of an inner coating 31 and an outer coating 32. The inner coating 31 is a layer disposed on the outer periphery of the coil body 20. The outer coating 32 is a layer disposed on the outer periphery of the inner coating 31. In this embodiment, both the inner coating 31 and the outer coating 32 are integrally formed continuous bodies. However, the inner coating 31 may also be a discontinuous body formed with a portion of it discontinuously. The inner coating 31 is an example of a first coating within the scope of the technical solution, and the outer coating 32 is an example of a second coating within the scope of the technical solution.

[0042] The outer coating 32 has a higher swelling capacity than the inner coating 31. In this specification, a high swelling capacity of the coating refers to a greater expansion (more water retention) when the coating is immersed in physiological saline. As an indicator of high swelling capacity, the change in film thickness measured using a laser microscope or similar device, i.e., the swelling film thickness, can be used. The swelling film thickness of the outer coating 32 is preferably 1.2 times or more than the swelling film thickness of the inner coating 31, more preferably 1.5 times or more, and even more preferably 2.0 times or more. The swelling film thickness of the coating can be measured using a VFX series laser microscope (manufactured by Gisens), an OPTELICS series white confocal microscope (manufactured by Lasertec), or an F40 series optical interferometer (manufactured by Philmetrix). In particular, when using the VFX-8710 as a laser microscope, the guide wire 100 with the predetermined hydrophilic coating applied in a dry state is observed, and the thickness of the dry film from the coil body 20 to the surface of the coating 30 is measured. Then, physiological saline is added to the observation section, and after the coil body 20 and the coating 30 are immersed in physiological saline for more than 10 seconds, the thickness of the swollen film can be measured by further measuring the coil body 20 and the coating 30 with a laser microscope.

[0043] For example, as the forming material of the inner coating 31, polyvinyl alcohol (PVA), hydrophilic polyurethane resins (e.g., Hydro Thane (Mitsubishi Chemical), Hydro MED (Mitsubishi Chemical), Bionate (DSM), Tecophilic (Lubrizol), HPU (Dai Nippon Seika)), modified polyolefin resins (e.g., polyethylene-acrylic acid (Unitika), BONDINE (Tokyo Materials)), etc., can be used, and polyvinyl alcohol (PVA) and hydrophilic polyurethane resin (Hydro Thane) are particularly preferred. Furthermore, as the forming material of the outer coating 32, hyaluronic acid, carboxybetaine, phosphate betaine, sulfobetaine, polyvinylpyrrolidone, maleic acid, acrylic acid, methacrylic acid, dimethacrylamide, methoxyethyl acrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, polyethylene glycol, and copolymers thereof can be used, and hyaluronic acid, carboxybetaine, phosphate betaine-dimethacrylamide, and copolymers thereof are more preferred. If these materials are used to form the inner coating 31 and the outer coating 32, the swelling property of the outer coating 32 can be made higher than that of the inner coating 31.

[0044] like Figure 2 As shown, in this embodiment, in the coating 30 (30d) in its normal state (dry state), the thickness of the outer coating 32 is thicker between the wires 21 than at the position directly above the wires 21 of the coil body 20. More specifically, in a cross-section including the central axis AX of the coil body 20 ( Figure 2 In the cross-section shown, the thickness T2b of the outer coating 32 on the vertical bisecting line VL3 of the imaginary line segment VL4 connecting the center point P1 (hereinafter referred to as "first center point P1d") of one cross-section 21d of the wire 21 connecting the coil body 20 and the center point P1 (hereinafter referred to as "second center point P1p") of another cross-section 21p adjacent to the aforementioned one cross-section 21d on the base end side of the wire 21 is thicker than the thickness T2ad of the outer coating 32 on the first imaginary straight line VL1 passing through the aforementioned first center point P1d and perpendicular to the central axis AX, and thicker than the thickness T2ap of the outer coating 32 on the second imaginary straight line VL2 passing through the aforementioned second center point P1p and perpendicular to the central axis AX. Furthermore, in this embodiment, such a thickness relationship holds for any combination of any two adjacent cross-sections of the wire 21 in any cross-section containing the central axis AX of the coil body 20. The coil body 20 is a structure in which the wire 21 is wound into a spiral shape. Therefore, in the coating 30 (30d) in the normal state, the thicker part of the outer coating 32 is distributed in a spiral shape between the wires 21.

[0045] Furthermore, in the cross-section of the coating 30 (30d) in its normal state, including the central axis AX of the coil body 20, the thickness T2b of the outer coating 32 on the vertical bisecting line VL3 is preferably at least 1.2 times the thickness T2ad of the outer coating 32 on the first imaginary line VL1 and at least 1.2 times the thickness T2ap of the outer coating 32 on the second imaginary line VL2, and more preferably at least 2 times the thickness T2ad and at least 2 times the thickness T2ap. Additionally, the thickness T2b of the outer coating 32 on the vertical bisecting line VL3 is preferably at least 5 times the thickness T2ad of the outer coating 32 on the first imaginary line VL1 and at least 5 times the thickness T2ap of the outer coating 32 on the second imaginary line VL2, and more preferably at least 3.5 times the thickness T2ad and at least 3.5 times the thickness T2ap. The thickness T2b of the outer coating 32 on the aforementioned vertical bisecting line VL3 is, for example, about 1.5 μm to 4.0 μm, and the thickness T2ad of the outer coating 32 on the aforementioned first imaginary straight line VL1 and the thickness T2ap of the outer coating 32 on the aforementioned second imaginary straight line VL2 are, for example, about 0.5 μm to 2.0 μm.

[0046] Furthermore, in this embodiment, in the normally applied coating 30 (30d), the thickness of the inner coating 31 is thicker between the wires 21 than at the position directly above the wires 21 of the coil body 20. More specifically, in a cross-section including the central axis AX of the coil body 20 ( Figure 2 In the cross-section shown, the thickness T1b of the inner coating 31 on the vertical bisecting line VL3 is thicker than the thickness T1ad of the inner coating 31 on the first imaginary line VL1, and thicker than the thickness T1ap of the inner coating 31 on the second imaginary line VL2. Furthermore, in this embodiment, in the normally positioned coating 30 (30d), the overall thickness of the coating 30 increases between the wires 21 compared to the position directly above the wires 21 of the coil body 20. More specifically, in the cross-section including the central axis AX of the coil body 20, the thickness Tb of the coating 30 on the vertical bisecting line VL3 is thicker than the thickness Tad of the coating 30 on the first imaginary line VL1, and thicker than the thickness Tap of the coating 30 on the second imaginary line VL2.

[0047] When coating 30 is changed from its normal state to a swollen state, such as Figure 3As shown, each layer constituting the coating 30 absorbs moisture and expands. The outer coating 32 has a higher swelling capacity than the inner coating 31, therefore the expansion amount of the outer coating 32 is greater than that of the inner coating 31. The coating 30 of this embodiment has the above-described structure in its normal state (the outer coating 32, which has a higher swelling capacity, has a thicker thickness between the wires 21 of the coil body 20). Therefore, when transitioning from the normal state to the swollen state, the thicker portion of the outer coating 32 in the normal state expands significantly to form a mountain 36. That is, the coating 30 (30w) is configured to have a mountain 36 that protrudes in the peripheral direction of the guide wire 100 in the swollen state.

[0048] The apex P2 of the hill 36 is not located directly above the wire 21 of the coil body 20, but rather between the wires 21. More specifically, in the cross section containing the central axis AX of the coil body 20 ( Figure 3 In the cross-section shown, the apex P2 of the mountain 36 is located at a position closer to the base end than the first imaginary line VL1 and closer to the front end than the second imaginary line VL2. Figure 3 The range R1). In other words, the apex P2 of the hill 36 is not located on the first imaginary line VL1 and the second imaginary line VL2, but exists at a position other than on the first imaginary line VL1 and the second imaginary line VL2. Furthermore, in this embodiment, such a positional relationship of the apex P2 of the hill 36 is established for the combination of cross sections of any two adjacent wires 21 in any cross section containing the central axis AX of the coil body 20. As described above, the coil body 20 is a structure in which the wires 21 are wound into a spiral shape. In the coating 30 (30d) in the normal state, the thicker portion of the outer coating 32 is distributed spirally between the wires 21. Therefore, in the coating 30 (30w) in the swollen state, the hill 36 is continuously formed with its apex P2 extending spirally between the wires 21.

[0049] Furthermore, in this embodiment, in the cross section of the coating 30 (30w) in the swollen state, including the central axis AX of the coil body 20, the apex P2 of the hill 36 exists in a direction perpendicular to the central axis AX (in Figure 3 In the example, this is the Y-axis direction, and the position does not overlap with the cross-section of the wire 21. In other words, the apex P2 of the hill 36 exists closer to the base end than the fifth imaginary line VL5, which passes through the endpoint of the base end of a cross-section 21d of the wire 21 of the coil body 20 and is perpendicular to the central axis AX, and exists closer to the front end than the sixth imaginary line VL6, which passes through the endpoint of another cross-section 21p adjacent to the base end of the aforementioned cross-section 21d and is perpendicular to the central axis AX. Figure 3The range is R2). More specifically, in this embodiment, in the cross section of the coating 30 (30w) in the swollen state, including the central axis AX of the coil body 20, the apex P2 of the hill 36 is located on or near the aforementioned vertical bisecting line VL3. Furthermore, since the hill 36 is a portion protruding in the outer peripheral direction of the guide wire 100, the apex P2 of the hill 36 is located on the outer peripheral side of the imaginary line segment VL4 described above.

[0050] In the cross section of the coating 30 (30w) in the swollen state, which includes the central axis AX of the coil body 20, the thickness T2b of the outer coating 32 at the position of the apex P2 of the hill 36 is, for example, about 4.0 μm to 16.0 μm, and the thickness T2ad of the outer coating 32 on the first imaginary straight line VL1 and the thickness T2ap of the outer coating 32 on the second imaginary straight line VL2 are, for example, about 1.0 μm to 6.0 μm.

[0051] A-3. Method for manufacturing guidewire 100:

[0052] The manufacturing method of the guide wire 100 in this embodiment is as follows. First, the coil body 20 is joined to the mandrel 10 through the joints (front end side joint 51, base end side joint 56, and intermediate fixing part 61) to produce the guide wire 100 before the coating 30 is formed. The guide wire 100 is then cleaned as needed.

[0053] Next, an inner coating 31 with low swelling properties is formed on the guidewire 100 using a predetermined film forming method. For example, a solution for preparing the inner coating 31 is prepared using a resin material with low swelling properties, and the inner coating 31 is formed by dip-coating with this solution. Next, an outer coating 32 with high swelling properties is formed on the guidewire 100 having the inner coating 31 using a predetermined film forming method. For example, a solution for preparing the outer coating 32 is prepared using a resin material with high swelling properties, and the outer coating 32 is formed by dip-coating with this solution. By using the above methods, a guidewire 100 having a coating 30 composed of an inner coating 31 and an outer coating 32 can be manufactured.

[0054] Furthermore, when forming the outer coating 32, the thickness of the outer coating 32 is thicker between the wires 21 than at the position directly above the wires 21 of the coil body 20. This achieves a structure where, when the coating 30 is moved from its normal state (dry state) to its swollen state, the apex P2 of the mountain 36 of the coating 30 is not located directly above the wires 21 of the coil body 20, but rather between the wires 21. Additionally, the degree of protrusion of the mountain 36 of the coating 30 in the swollen state can be adjusted, for example, by adjusting the thickness of the outer coating 32, the inner coating 31, or by adjusting the spacing between the wires 21 of the coil body 20.

[0055] A-4. The function and effect of guidewire 100:

[0056] The guide wire 100 of this embodiment has the structure described above, thus achieving a high degree of balance between lubrication and the passage of compatible devices. This will be explained below.

[0057] Figure 4 This is an explanatory diagram showing the state of the guidewire 100 in use according to this embodiment. When the guidewire 100 is inserted into the human body, the coating 30 absorbs moisture and swells (see reference). Figure 3 Afterwards, guided by guidewire 100, a balloon catheter or similar device DE is inserted into the human body. At this time, for example, in the bend of the device DE, if the device DE is pressed against the coating 30 (30w), then... Figure 4 As shown, the coating 30 is flattened and the surface becomes smooth, and moisture seeps out from the coating 30 to form a thin moisture film WA between the smooth surface of the coating 30 and the co-operating device DE. As a result, lubrication between the guide wire 100 and the co-operating device DE can be ensured.

[0058] Figure 5 and Figure 6 This is an explanatory diagram showing the structure of the coating 30X in the guide wire 100X of the comparative example. Figure 5 This indicates the structure of coating 30X (30Xd) under normal (dry) conditions. Figure 6 This represents the structure of the coating 30X(30Xw) in the swollen state.

[0059] like Figure 5 and Figure 6 As shown, the comparative example coating 30X is composed of a single layer. The swelling property of the comparative example coating 30X is approximately the same as that of the outer coating 32 constituting the coating 30 of the above embodiment. Furthermore, in the comparative example coating 30X, the thickness under normal conditions is approximately constant at each location. Therefore, the shape of the outer peripheral surface of the coating 30X is the same as the shape of the outer peripheral surface of the wire 21 of the coil body 20. However, due to the relationship between the coating 30X and the gap between the wires 21 of the coil body 20, the thickness Tb of the coating 30X on the vertical bisecting line VL3 is slightly thicker than the thickness Tad of the coating 30X on the first imaginary line VL1, and slightly thicker than the thickness Tap of the coating 30X on the second imaginary line VL2. The thicknesses Tad and Tap of the comparative example coating 30X at the positions on the first imaginary line VL1 and the second imaginary line VL2 are approximately the same as the thicknesses Tad and Tap of the coating 30 of the above embodiment at those positions.

[0060] The comparative example coating 30X has such a structure in its normal state that, when transitioning from the normal state to the swollen state, as... Figure 6As shown, a mountain 36 protruding in the outer peripheral direction is formed of the guide wire 100X. However, the coating 30X of the comparative example has a single-layer structure and a substantially constant thickness, so the apex P2 of the mountain 36 is located directly above the wire 21 of the coil body 20. That is, the apex P2 of the mountain 36 is located on the first imaginary line VL1 and the second imaginary line VL2. In the swollen state, the thickness Tad and Tap of the coating 30X (30Xw) of the comparative example at the position of the apex P2 of the mountain 36 is thinner than the thickness Tb of the coating 30 (30w) of the above embodiment at the position of the apex P2 of the mountain 36.

[0061] Figure 7 This is an explanatory diagram showing the state of the guidewire 100X in use as described in the comparative example. Similar to the embodiment described above, in the comparative example, when the guidewire 100X is inserted into the human body, the coating 30X absorbs moisture and swells (see reference). Figure 6 Afterwards, the device DE is guided by the guide wire 100X and inserted into the human body. At this time, for example, in the curved part of the device DE, if the device DE is pressed against the coating 30X (30Xw), then as... Figure 7 As shown, coating 30X is flattened.

[0062] In the comparative examples, such as Figure 6 As shown, the apex P2 of the hill 36 of the coating 30X (30Xw) in the swollen state is located directly above the wire 21 of the coil body 20. The portion of the coating 30X located directly above the wire 21 has a small "clearance" when subjected to stress from the outer periphery because the wire 21 acts as a substrate, making it unable to flexibly withstand the stress from the combined device DE. As a result, in the comparative example, as... Figure 7 As shown, the coating 30X is flattened and comes into contact with the wire 21 of the coil body 20 using the device DE, which may reduce lubricity.

[0063] Furthermore, in the comparative example, to avoid contact between the device DE and the wire 21 of the coil body 20, it is also possible to increase the thickness of the coating 30X. However, if the thickness of the coating 30X is simply increased, the portion of the coating 30X located directly above the wire 21 of the coil body 20 (mountain 36) will be too thick during swelling, and the passability of the device DE may deteriorate.

[0064] In contrast, in the guide wire 100 of this embodiment, the coating 30 is configured to have a ridge 36 that protrudes in the peripheral direction of the guide wire 100 in a swollen state. Therefore, the ridge 36 of the coating 30 effectively retains water and imparts high lubricity to the guide wire 100.

[0065] Furthermore, in the guide wire 100 of this embodiment, in the cross section including the central axis AX of the coil body 20, the apex P2 of the mountain 36 of the coating 30 in the swollen state is located closer to the base end than the first imaginary straight line VL1 that passes through the first center point P1d of a cross section 21d of the wire 21 of the coil body 20 and is perpendicular to the central axis AX, and is located closer to the front end than the second imaginary straight line VL2 that passes through the second center point P1p of another cross section 21p adjacent to the base end of the cross section 21d and is perpendicular to the central axis AX. That is, the apex P2 of the mountain 36 of the coating 30 in the swollen state is located between the wires 21 of the coil body 20. The portion of the coating 30 located between the wires 21 is the portion where the influence of the wire 21 as a base is small, and therefore the portion with a large "clearance" when subjected to stress from the outer periphery. Therefore, if the apex P2 of the mountain 36 exists in this portion of the coating 30 (in other words, the volume of the coating 30 in this portion is large), the stress from the combined device DE can be dispersed. Therefore, according to the guide wire 100 of this embodiment, even if the coating 30 is flattened, it is possible to effectively suppress and use the device DE to contact the wire 21 of the coil body 20.

[0066] In addition, the portion of the coating 30 located between the wires 21 is small and easy to move due to the presence of the base wires 21. Therefore, even if the apex P2 of the mountain 36 of the coating 30 is located between the wires 21 of the coil body 20, the passability of the device DE can be well maintained.

[0067] As described above, the guide wire 100 according to this embodiment can achieve a high degree of balance between lubrication and the passability of the accompanying device DE.

[0068] Furthermore, in this embodiment, in the cross-section including the central axis AX of the coil body 20, the apex P2 of the hill 36 exists at a position that does not overlap with the cross-section of the wire 21 of the coil body 20 in a direction perpendicular to the central axis AX. The portion of the coating 30 that does not overlap with the cross-section of the wire 21 of the coil body 20 in a direction perpendicular to the central axis AX is a portion where the influence of the wire 21 as a base is very small, and therefore has a very large "playback" when subjected to stress from the outer periphery. Therefore, if the apex P2 of the hill 36 exists in this portion of the coating 30, the stress from the co-working device DE can be effectively dispersed. Therefore, according to the guide wire 100 of this embodiment, even if the coating 30 is flattened, contact between the co-working device DE and the wire 21 of the coil body 20 can be more effectively suppressed, and the lubricity of the guide wire 100 can be more effectively improved.

[0069] Furthermore, in the guide wire 100 of this embodiment, the coating 30 includes an inner coating 31 disposed on the outer periphery of the coil body 20, and an outer coating 32 disposed on the outer periphery of the inner coating 31 and having a higher swelling capacity than the inner coating 31. In a normal state, in a cross-section including the central axis AX of the coil body 20, the thickness T2b of the outer coating 32 on the vertical bisecting line VL3 is thicker than the thickness T2ad of the outer coating 32 on the first imaginary line VL1, and thicker than the thickness T2ap of the outer coating 32 on the second imaginary line VL2. The guide wire 100 of this embodiment has such a structure that the apex P2 of the mountain 36 of the coating 30 in the swollen body exists at a position closer to the base end than the first imaginary line VL1 and closer to the front end than the second imaginary line VL2. Therefore, according to the guide wire 100 of this embodiment, as described above, lubricity and the passage of the accompanying device DE can be balanced in a high degree.

[0070] Furthermore, under normal conditions, in the cross-section including the central axis AX of the coil body 20, it is preferable that the thickness T2b of the outer coating 32 on the aforementioned vertical bisecting line VL3 is at least 1.2 times the thickness T2ad of the outer coating 32 on the aforementioned first imaginary straight line VL1, and at least 1.2 times the thickness T2ap of the outer coating 32 on the aforementioned second imaginary straight line VL2. With this structure, in the coating 30 of the swollen body, it is possible to achieve a structure in which the thickness of the portion located between the wires 21 of the coil body 20 is proportionally greater than the thickness of the portion located directly above the wires 21, further balancing lubricity and the passage of the accompanying device DE in a high-dimensional manner.

[0071] B. Variations:

[0072] The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various ways without departing from its spirit, for example, the following modifications are also possible.

[0073] The structure of the guide wire 100 in the above embodiment is merely an example and can be modified in various ways. For example, in the above embodiment, the coating 30 is a two-layer structure of an inner coating 31 and an outer coating 32, but the coating 30 can also be a structure of three or more layers with one or more other layers disposed between the inner coating 31 and the outer coating 32.

[0074] In the above embodiment, in the cross section of the coating 30 (30w) in the swollen state containing the central axis AX of the coil body 20, the apex P2 of the mountain 36 is located on or near the vertical bisecting line VL3. However, the apex P2 of the mountain 36 may exist in other positions as long as it is not on the first imaginary line VL1 or the second imaginary line VL2.

[0075] In the above embodiment, in the swollen coating 30 (30w), the mountain 36 is formed continuously in a spiral shape, but the mountain 36 can also be formed discretely.

[0076] In the above embodiment, the relationship that the apex P2 of the mountain 36 is located at a position closer to the base end than the first imaginary line VL1 and at a position closer to the front end than the second imaginary line VL2 holds true for any combination of cross sections of any two adjacent wires 21 in any cross section containing the central axis AX of the coil body 20. However, this relationship is immediately valid for at least one combination of cross sections of any two adjacent wires 21 in at least one cross section containing the central axis AX of the coil body 20. Similarly, in the above embodiment, the relationship that the thickness T2b of the outer coating 32 on the vertical bisecting line VL3 is thicker than the thickness T2ad of the outer coating 32 on the first imaginary line VL1 and thicker than the thickness T2ap of the outer coating 32 on the second imaginary line VL2 holds true for any combination of cross sections of any two adjacent wires 21 in any cross section containing the central axis AX of the coil body 20. However, this relationship is immediately valid for at least one combination of cross sections of any two adjacent wires 21 in at least one cross section containing the central axis AX of the coil body 20.

[0077] Hereinafter, in order to make the above-described content of the present invention clearer, embodiments of the present invention will be described.

[0078] [Example 1]

[0079] First, a guide wire 100 (guide wire 100 before coating 30 is formed) is made having a mandrel 10, a coil body 20, a front end side joint 51, a base end side joint 56 and an intermediate fixing part 61. The surface of the guide wire 100 is cleaned by wiping it with a non-woven cloth infused with isopropyl alcohol (IPA).

[0080] Next, polyvinyl alcohol (molecular weight 2600, saponification degree ≥ 98%, manufactured by Mitsubishi Chemical, product name NH26-S) was dissolved in hot water at a concentration of 5%, and 0.16% of polycarbodiimide (manufactured by Nisshinbo, product name: CARBODILITE) was added as a crosslinking agent to obtain a solution for the inner coating 31. Using the obtained solution, the guide wire 100 before the formation of the above coating 30 was dipped and coated, and then heated and dried at 70°C for 1 hour, thereby obtaining the guide wire 100 with the inner coating 31 formed.

[0081] Additionally, sodium hyaluronate (molecular weight approximately 1 million) was dissolved at 0.8 wt% in a mixed solution of water and N-methylpyrrolidone at a ratio of 85:15 to obtain a solution for the outer coating 32. Using this solution, a guidewire 100 having the aforementioned inner coating 31 was dipped in and dried at 120°C for 1 hour, thereby forming the outer coating 32. Thus, a guidewire 100 having a coating 30 consisting of the inner coating 31 and the outer coating 32 was obtained.

[0082] [Membrane Shape Evaluation Method]

[0083] As a measurement of the swelling film thickness, the guide wire 100 of Example 1 with coating 30 was immersed in physiological saline for 20 seconds, and then the cross-section of the transparent film was measured using a laser microscope (KEYENCE VFX-8710). Figure 8 This is an explanatory diagram showing the measurement results of the swelling film thickness of the guide wire 100 in Example 1. Figure 8 The whitest part is the part with the greatest laser reflection, corresponding to the outermost surface of each wire 21 constituting the coil body 20. The undulating portion observed above it is formed by the coating 30 (30w) swollen with saline solution. Within the coating 30 (30w), an upwardly protruding hill 36 is formed at the center of the outermost surface (the part with the greatest reflection) of each wire 21 of the coil body 20. Figure 8 In the illustrated embodiment 1, the thickness Ta of the coating 30 (30w) at the position directly above the wire 21 of the coil body 20 is 5.80 μm, and the thickness Tb of the coating 30 (30w) at the position of the hill 36 (the position between the wires 21 of the coil body 20) is 12.40 μm.

[0084] [Lubricity Evaluation Methods]

[0085] The base end of the balloon catheter (Kamui 3.00mm × 15mm, manufactured by Asahi Intec) used as the guidewire 100 is wound once around a cylinder with an outer diameter of 30mm from the tip 105mm to recreate the bend of the coronary artery. The lubricity of the guidewire 100 of Example 1 when inserted into the balloon catheter in this state was evaluated. As a result, it was confirmed that the guidewire 100 of Example 1 exhibited very low resistance during insertion, demonstrating high lubricity.

[0086] As a more rigorous test, the balloon catheter was repeatedly inserted and withdrawn 50 times with the guidewire 100 to evaluate changes in lubricity. As a result, in Example 1, even after 50 repeated insertions and withdrawals, no change in resistance was observed, maintaining high lubricity.

[0087] Based on the above observation and evaluation results, it was observed that in the guidewire 100, the mountain 36 of the coating 30 (30w) at the position between the wires 21 of the coil body 20 deforms when pressed into the balloon catheter used as a combined device, and maintains high lubricity by providing a water film at the apex of the wires 21 of the coil body 20.

[0088] The present invention is not limited to the conditions of the above embodiments, and various substrates and coating agents can be selected without departing from the spirit of the invention.

[0089] Symbol Explanation

[0090] 10—Mandrel, 11—Narrow diameter section, 12—First tapered section, 13—First coarse diameter section, 14—Second tapered section, 15—Second coarse diameter section, 20—Coil body, 21—Wire, 30—Coating, 31—Inner coating, 32—Outer coating, 36—Mountain section, 51—Front end side joint, 56—Base end side joint, 61—Intermediate fixing section, 100—Guide wire, AX—Central shaft, DE—Combined equipment, WA—Membrane.

Claims

1. A guidewire, characterized in that, have: mandrel; A coil body having wire wound in a spiral around the outer periphery of the mandrel; and A coating is applied to the outer periphery of the coil body. The coating is configured to continuously cover the outer periphery of a plurality of adjacent wires along the long side of the coil body, and has a ridge protruding toward the outer periphery of the guide wire in a swollen state. In a cross-section containing the central axis of the coil body, the apex of the mountain exists at a position closer to the base end than a first imaginary line passing through the center point of one cross-section of the wire and perpendicular to the central axis, and at a position closer to the front end than a second imaginary line passing through the center point of another cross-section of the wire adjacent to the base end of the one cross-section and perpendicular to the central axis.

2. The guidewire according to claim 1, characterized in that, In the cross-section containing the central axis of the coil body, the apex of the mountain exists in a position that does not overlap with the cross-section of the wire in a direction perpendicular to the central axis.

3. The guidewire according to claim 1, characterized in that, The apex of the mountain in the coating is formed continuously in a spiral manner extending between the wires of the coil body.

4. The guidewire according to claim 1, characterized in that, The mountain-like structures of the coating are formed discretely.

5. A guidewire, characterized in that, have: mandrel; A coil body having wire wound in a spiral around the outer periphery of the mandrel; and A coating is applied to the outer periphery of the coil body. The coating comprises: A first coating is disposed on the outer periphery of the coil body; and The second coating, which is disposed on the outer periphery of the first coating, has a higher swelling capacity than the first coating. In a cross-section containing the central axis of the coil body, the thickness of the second coating on the perpendicular bisecting line of an imaginary line segment connecting a first center point (which is the center point of one cross-section of the wire) and a second center point (which is the center point of another cross-section of the wire adjacent to the one cross-section on the base end side) is greater than the thickness of the second coating on a first imaginary line passing through the first center point and perpendicular to the central axis, and also greater than the thickness of the second coating on a second imaginary line passing through the second center point and perpendicular to the central axis.

6. The guidewire according to claim 5, characterized in that, In the cross section containing the central axis of the coil body, the thickness of the second coating on the vertical bisecting line is more than 1.2 times the thickness of the second coating on the first imaginary straight line, and more than 1.2 times the thickness of the second coating on the second imaginary straight line.

7. The guidewire according to claim 5, characterized in that, The apex of the mountain in the coating is formed continuously in a spiral extending between the wires of the coil body.

8. The guidewire according to claim 5, characterized in that, The mountain-like structures of the coating are formed discretely.

9. The guidewire according to claim 5, characterized in that, The thickness of the outer coating at the apex of the mountain is 4.0 μm to 16.0 μm.

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