Medical device

Abstract

A catheter 1 (medical device) comprises: a tubular inner layer 4; a tubular first reinforcement body 5 that is disposed outside the inner layer 4, has a distal end positioned closer to a proximal end of the catheter than a distal end of the inner layer 4, and is formed of a plurality of first elementary wires 51, the first reinforcement body 5 having, at a distal end portion thereof, a diameter-enlarged portion 52 having an inner diameter increasing toward the distal end, and also having a bonding portion 53 at which at least two of the plurality of first elementary wires 51 are bonded together; a tubular second reinforcement body 6 that is disposed outside the first reinforcement body 5, has a distal end positioned closer to the proximal end of the catheter than the distal end of the first reinforcement body 5, and is formed of at least one second elementary wire 61; and an outer layer 7 covering the inner layer 4, the first reinforcement body 5, and the second reinforcement body 6, wherein the outer layer 7 has an outer layer distal end portion 71 having a first hardness and covering the diameter-enlarged portion 52 and the bonding portion 53, and an outer layer body portion 72 positioned adjacent to a proximal end of the outer layer distal end portion 71 and having a second hardness lower than the first hardness. The catheter 1 is highly robust and resistant to breakage.

Description

medical devices

[0001] The present disclosure relates to medical devices such as catheters that are introduced into the body and used to treat strictures or obstructions in blood vessels or digestive organs.

[0002] Conventionally, as a medical device used, for example, when treating stenosis or occlusion in a blood vessel or a digestive organ, a catheter has been known in which a plurality of reinforcing members are arranged on the outside of the lumen for the purposes of preventing deformation of the shape of the lumen, exerting rotational torque when entering the blood vessel, etc. For example, Patent Document 1 discloses a catheter including an inner layer, a braid as a first reinforcing member wound around the outside of the inner layer, a coil as a second reinforcing member wound around the outside of the first reinforcing member, and an outer layer that covers the inner layer, the first reinforcing member, and the second reinforcing member.

[0003] International Publication No. 2019 / 003425

[0004] In the catheter described in Patent Document 1, when the outer layer is caught in a narrowed or blocked area and is pushed or pulled, force is applied to the joint between the inner and outer layers, causing the outer layer to peel off from the inner layer, or the reinforcement body is deformed and comes off from the outer layer, which could result in damage to the catheter.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a medical device that is highly robust and less susceptible to breakage.

[0006] In order to achieve the above-mentioned object, the present disclosure provides a medical device comprising: a tubular inner layer; a tubular first reinforcing body arranged outside the inner layer, with a tip located proximal to the tip of the inner layer, the first reinforcing body being formed from a plurality of first wires, the tip portion being provided with an expanding diameter section whose inner diameter expands toward the tip and a fastening section where at least two of the plurality of first wires are fastened to each other; a tubular second reinforcing body arranged outside the first reinforcing body, with a tip located proximal to the tip of the first reinforcing body, the second reinforcing body being formed from at least one second wire; and an outer layer covering the inner layer, the first reinforcing body, and the second reinforcing body, the outer layer having a first hardness and including an outer layer tip portion covering the expanding diameter section and the fastening section, and an outer layer main body portion located proximal to the outer layer tip portion and having a second hardness lower than the first hardness (Disclosure 1).

[0007] According to this disclosure (Disclosure 1), by increasing the rigidity of the outer layer tip portion more than that of the outer layer main body portion, and by providing an enlarged diameter portion and a fixing portion at the tip portion of the first reinforcing body located within the outer layer tip portion, a structure is achieved that makes it difficult for the first reinforcing body to detach from the outer layer, resulting in a medical device that is highly robust and less likely to break.

[0008] In the above disclosure (Disclosure 1), the fixing portion may be provided on the expanded diameter portion of the first reinforcing body (Disclosure 2).

[0009] According to this disclosure (Disclosure 2), the engagement between the enlarged diameter portion of the first reinforcing body and the tip end portion of the outer layer is strengthened, making it more difficult for the first reinforcing body to separate from the outer layer.

[0010] In the above disclosures (Disclosures 1 and 2), the fixing portion may be located at a tip of the first reinforcing body (Disclosure 3).

[0011] According to this disclosure (Disclosure 3), by fixing the tip of the first reinforcing body, the first reinforcing body has a structure that is less likely to come apart, and in particular, when an expanded diameter portion is provided at the tip of the first reinforcing body, the fixed portion is provided at the most expanded diameter part of the first reinforcing body, resulting in a stable structure in which the tip of the outer layer is less likely to detach from the medical device.

[0012] In the above disclosures (Disclosures 1-3), the fixing portion may be formed in a block shape (Disclosure 4).

[0013] According to this disclosure (Disclosure 4), the fixing portion is formed in a block shape, which increases the contact area between the outer layer and the first reinforcing body, and the fixing portion functions as an anchor at the tip of the outer layer, thereby improving the effect of preventing the first reinforcing body from separating from the outer layer.

[0014] In the above disclosures (Disclosures 1-4), the fixing portion may be formed in a substantially spherical shape (Disclosure 5).

[0015] According to this disclosure (Disclosure 5), since the fixing portion is formed in an approximately spherical shape, when it is formed at the tip of the first reinforcing body, the tip is not sharp, so it is possible to prevent it from breaking through the outer layer, and even if it protrudes outward from the outer layer, it is possible to prevent it from damaging the inner walls of blood vessels or digestive organs.

[0016] In the above disclosures (Disclosures 1-5), the outer layer tip portion may have a tapered portion whose outer diameter decreases toward the tip, and a straight portion located on the base end side of the tapered portion and whose outer diameter is constant, and the tip of the first reinforcing body may be located within the straight portion (Disclosure 6).

[0017] According to this disclosure (Disclosure 6), the provision of a tapered portion at the distal end of the outer layer distal portion can improve the insertability of the medical device, and the absence of the first reinforcing body within the tapered portion ensures the flexibility of the distal portion of the outer layer distal portion. If the distal end of the first reinforcing body is within the straight portion, it can be prevented from protruding from the distal end of the outer layer distal portion.

[0018] In the above disclosures (Disclosures 1-6), the outer layer tip portion and the outer layer main body portion may be formed from the same type of resin material (Disclosure 7).

[0019] According to this disclosure (Disclosure 7), the adhesion between the outer layer tip portion and the outer layer main body portion can be improved, thereby further preventing the outer layer tip portion from detaching from the medical device.

[0020] In the above disclosures (Disclosures 1-7), the outer layer tip portion and the outer layer main body portion may be formed from the same resin material (Disclosure 8).

[0021] According to this disclosure (Disclosure 8), the adhesion between the outer layer tip portion and the outer layer main body portion can be further improved, thereby further preventing the outer layer tip portion from detaching from the medical device.

[0022] In the above disclosures (Disclosures 1-8), the outer diameter of the first reinforcing body at the position where the fixing portion is formed may be larger than the inner diameter of the second reinforcing body (Disclosure 9).

[0023] According to this disclosure (Disclosure 9), the outer diameter of the first reinforcement body at the location where the fixing portion is formed is larger than the inner diameter of the second reinforcement body, making the second reinforcement body less likely to detach, thereby further improving the robustness of the entire medical device.

[0024] 1A and 1B are diagrams illustrating the overall structure of a catheter according to an embodiment of the present disclosure, a diagram illustrating the internal structure of the catheter according to the same embodiment, a diagram illustrating a first modified example of the catheter according to the same embodiment, and a diagram illustrating a second modified example of the catheter according to the same embodiment.

[0025] A catheter 1 according to an embodiment of the present disclosure will be described below with reference to the drawings. The catheter 1 is a medical device used, for example, to treat strictures in cardiac blood vessels, bile ducts, or pancreatic ducts, or to aspirate bone marrow from bones. The distal end of the catheter 1 is the side that is inserted into the body, and the proximal end of the catheter 1 is the side that is operated by a surgeon such as a doctor. The present disclosure is not limited to the embodiments described below, and the described embodiments are merely examples for explaining the technical features of the present disclosure. The shapes and dimensions shown in the drawings are shown solely to facilitate understanding of the contents of the present disclosure and do not accurately reflect the actual shapes and dimensions.

[0026] As used herein, the term "distal side" refers to the axial direction of the catheter, in which the catheter advances toward the target site. The term "base side" refers to the axial direction of the catheter, in the direction opposite the distal side. The term "distal" refers to the distal end of any component or component, and the term "base end" refers to the proximal end of any component or component. The term "distal portion" refers to the portion of any component or component that includes the distal end and extends from the distal end toward the proximal end to the middle of the component, and the term "base end" refers to the portion of any component or component that includes the proximal end and extends from the proximal end toward the distal end to the middle of the component. In Figure 1, the left side of the illustration is the "distal side" that is inserted into the body, and the right side is the "base side" that is operated by the operator.

[0027] 1 is an explanatory diagram showing the overall structure of a catheter 1 according to this embodiment. The catheter 1 includes a control unit 2 operated by an operator and a long catheter tube 3 connected to the tip of the control unit 2. The catheter tube 3 is a long tubular member having an internal lumen 41. The control unit 2 has an opening (not shown) that communicates with the internal lumen 41 of the catheter tube 3. A guidewire or other catheter inserted through the proximal opening of the control unit 2 can be guided through the internal lumen 41 of the catheter tube 3 to an opening on the tip side (the tip of an outer layer tip portion 71, described below) via the internal lumen 41 of the catheter tube 3.

[0028] Figure 2 is an explanatory diagram showing the internal structure of the catheter 1 (the catheter tube 3 thereof), and shows the cross-sectional structure of the tip portion (portion X in Figure 1). As shown in Figure 2, the catheter tube 3 of the catheter 1 comprises a tubular inner layer 4 having an inner lumen 41, a tubular first reinforcing body 5 arranged outside the inner layer 4, a tubular second reinforcing body 6 arranged outside the first reinforcing body 5, and an outer layer 7 covering the inner layer 4, the first reinforcing body 5, and the second reinforcing body 6. The first reinforcing body 5 has a tip located closer to the base end than the tip of the inner layer 4 and is formed from a plurality of metal wires 51. The second reinforcing body 6 has a tip located closer to the base end than the tip of the first reinforcing body 5 and is formed from at least one metal wire 61.

[0029] The inner layer 4 is formed from a resin material and has a lumen 41 inside which a guidewire, another catheter, or the like can be inserted. The resin material forming the inner layer 4 is not particularly limited. The resin material forming the inner layer 4 is preferably a resin that has good sliding properties with the guidewire, another catheter, or the like inserted into the lumen 41. Examples of resin materials forming the inner layer 4 include fluorine-based resins such as PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), PFA (perfluoroalkoxyalkane), FEP (perfluoroethylene propene), and ETFE (ethylene tetrafluoroethylene), as well as PE (polyethylene), PP (polypropylene), and the like. Part or all of the inner layer 4 may have a multilayer structure.

[0030] The first reinforcing body 5 is formed by a tubular braided body formed by weaving a plurality of metal wires (braid wires) 51 into a net-like (mesh-like) shape. The metal wires 51 forming the braided body may be flat wires or round wires. The first reinforcing body 5 may cover the entire inner layer 4 or may cover only a portion of the inner layer 4. In the catheter 1 of this embodiment, the tip of the first reinforcing body 5 is located closer to the proximal end than the tip of the inner layer 4, i.e., the tip portion of the inner layer 4 protrudes from the tip of the first reinforcing body 5. The material of the metal wires 51 is not particularly limited. Examples of materials for the metal wires 51 include stainless steel (SUS304, SUS316, etc.), gold, platinum, tungsten, titanium, nickel, or alloys containing any of these elements.

[0031] The second reinforcing body 6 is formed by a coil body formed by spirally winding a metal wire 61. The coil body may be formed by spirally winding a single metal wire 61 into a cylindrical shape, or may be a hollow stranded coil formed by twisting together a plurality of metal wires 61. The material of the metal wire 61 is not particularly limited. Examples of materials for the metal wire 61 include stainless steel (SUS304, SUS316, etc.), gold, platinum, tungsten, titanium, nickel, or alloys containing any of these elements. The second reinforcing body 6 may cover the entire first reinforcing body 5 or may cover only a portion of the first reinforcing body 5. In the catheter 1 of this embodiment, the distal end of the second reinforcing body 6 is located closer to the proximal end than the distal end of the first reinforcing body 5; that is, the distal end of the first reinforcing body 5 protrudes from the distal end of the second reinforcing body 6.

[0032] A joint 62 is provided at the tip of the second reinforcing body 6. The second reinforcing body 6 is welded to the outer peripheral surface of the first reinforcing body 5 via the joint 62. The joint 62 does not have to be provided at the tip of the second reinforcing body 6. In that case, the tip of the second reinforcing body 6 may be fixed to the outer peripheral surface of the first reinforcing body 5 by metal solder such as silver solder, gold solder, zinc, Sn—Ag alloy, or Au—Sn alloy, or may be fixed by an adhesive such as an epoxy adhesive. The joint 62 formed of a radiopaque metal may be used as a radiopaque marker.

[0033] The outer layer 7 is formed from a resin material and covers the inner layer 4, the first reinforcing body 5, and the second reinforcing body 6. There are no particular limitations on the resin material that forms the outer layer 7. Examples of resin materials that form the outer layer 7 include polyamide, polyamide elastomer, polyester, polyurethane, and polyurethane elastomer.

[0034] The outer layer 7 has an outer layer distal portion 71 having a first hardness and an outer layer main body portion 72 located proximal to the outer layer distal portion 71 and having a second hardness lower than the first hardness. The outer layer distal portion 71 and the outer layer main body portion 72 may be formed from the same type of resin material or may be formed from the same resin material. By forming the outer layer 7 using the same type of resin material but with different properties, the hardness of the resin forming the outer layer distal portion 71 may be higher than the hardness of the resin forming the outer layer main body portion 72. By forming the outer layer 7 from the same resin material, and the resin forming the outer layer distal portion 71 contains tungsten powder or the like, while the resin forming the outer layer main body portion 72 does not contain tungsten powder or the like, the hardness of the resin forming the outer layer distal portion 71 may be higher than the hardness of the resin forming the outer layer main body portion 72. The outer layer 7 may be formed from a single resin material, and the hardness of the resin forming the outer layer tip portion 71 may be made higher than the hardness of the resin forming the outer layer main body portion 72 by varying the amount of tungsten powder, etc., contained in the resin forming the outer layer tip portion 71 and the amount of tungsten powder, etc., contained in the resin forming the outer layer main body portion 72. Forming the outer layer tip portion 71 and the outer layer main body portion 72 from the same resin material can improve adhesion between the outer layer tip portion 71 and the outer layer main body portion 72, thereby further preventing the outer layer tip portion 71 from detaching from the catheter 1. Forming the outer layer tip portion 71 and the outer layer main body portion 72 from the same resin material can further improve adhesion between the outer layer tip portion 71 and the outer layer main body portion 72, thereby further preventing the outer layer tip portion 71 from detaching from the catheter 1.

[0035] The outer layer distal portion 71 has a tapered portion 711 whose outer diameter decreases toward the distal end, and a straight portion 712 located proximal to the tapered portion 711 and having a constant outer diameter. The distal end of the inner layer 4 is located within the tapered portion 711, and the distal end of the first reinforcing body 5 is located within the straight portion 712. The outer layer distal portion 71 is generally referred to as the distal tip. Providing the tapered portion 711 at the distal end of the outer layer distal portion 71 improves the insertability of the catheter 1, while the structure in which the first reinforcing body 5 is not present within the tapered portion 711 ensures flexibility of the distal portion of the outer layer distal portion 71. If the distal end of the first reinforcing body 5 is located within the straight portion 712, it is possible to prevent the first reinforcing body 5 from protruding from the distal end of the outer layer distal portion 71.

[0036] An expanded diameter section 52 whose inner diameter expands toward the tip is provided at the tip of the first reinforcing body 5 located within the outer layer tip section 71. In this embodiment, the inner diameter of the first reinforcing body 5 within the outer layer tip section 71 is structured so that it gradually increases from the base end toward the tip, and the expanded diameter section 52 is provided at the tip-most side of the first reinforcing body 5.

[0037] The tip of the first reinforcing body 5 located within the outer layer tip portion 71 is provided with a fixing portion 53 at which at least two of the multiple metal wires 51 forming the first reinforcing body 5 are fixed to each other. In this embodiment, the fixing portion 53 is provided in the expanded diameter portion 52 of the first reinforcing body 5. This further strengthens the engagement between the expanded diameter portion 52 of the first reinforcing body 5 and the outer layer tip portion 71, making it more difficult for the first reinforcing body 5 to detach from the outer layer 7.

[0038] By increasing the rigidity of the outer layer tip portion 71 more than that of the outer layer main body portion 72 and providing an enlarged diameter portion 52 and a fixed portion 53 at the tip portion of the first reinforcement body 5 located within the outer layer tip portion 71, a structure is achieved that makes it difficult for the first reinforcement body 5 to detach from the outer layer 7, resulting in a catheter 1 that is highly robust and less likely to break.

[0039] A method for manufacturing the catheter tube 3 having the above structure will now be described. First, the inner layer 4 is formed by coating the resin material of the inner layer 4 onto a metal core using an extrusion molding machine or the like; by applying a solution of the resin material of the inner layer 4 to the metal core and then drying it; or by immersing the metal core in a solution of the resin material of the inner layer 4 and then drying it. A tubular first reinforcing body 5 (braided body) formed by weaving a plurality of metal wires 51 into a mesh is wound around the inner layer 4. A second reinforcing body 5 (coiled body) is formed by spirally winding metal wires 61 around the first reinforcing body 5. In this state, a tube made of the resin material of the outer layer 7 is placed over the braided body and heated to thermally weld the braided body, thereby manufacturing the catheter tube 3. The tip portion of the first reinforcing body 5 is shaped, for example, by wrapping the first reinforcing body 5 around the inner layer 4, and then inserting a jig between the inner layer and the first reinforcing body 5 from the tip side of the first reinforcing body 5 to deform the first reinforcing body 5. The tip portion of the first reinforcing body 5 may also be shaped by wrapping the first reinforcing body 5 around the inner layer 4, and then applying a force in the axial direction while gripping the outer peripheral surface of the first reinforcing body 5 to deform the first reinforcing body 5.

[0040] In this embodiment, the fixing portion 53 is located at the tip of the first reinforcing body 5. Fixing the tip of the first reinforcing body 5 makes the first reinforcing body less likely to come apart. In particular, when an expanded diameter portion 52 is provided at the tip of the first reinforcing body 5, the fixing portion 53 is provided at the most expanded diameter portion of the first reinforcing body 5. By providing the fixing portion 53 at the most expanded diameter portion of the first reinforcing body 5, a stable structure is achieved in which the outer layer tip portion 71 is less likely to come off the catheter 1.

[0041] The fixing portion 53 is preferably formed in a block shape. By forming the fixing portion 53 in a block shape, the contact area between the outer layer tip portion 71 of the outer layer 7 and the first reinforcing body 5 increases, and the fixing portion 53 functions as an anchor at the outer layer tip portion 71, thereby improving the effect of preventing the first reinforcing body 5 from separating from the outer layer 7. In particular, in this embodiment, the fixing portion 53 is formed in a substantially spherical shape. By forming the fixing portion 53 in a substantially spherical shape, when the fixing portion 53 is formed at the tip of the first reinforcing body 5 as in this embodiment, the tip of the first reinforcing body 5 is not sharp, and therefore it is possible to prevent the tip from breaking through the outer layer. Even if the tip of the first reinforcing body 5 protrudes outward from the outer layer 7, it is possible to prevent damage to the inner walls of blood vessels and digestive organs.

[0042] The fixing portion 53 can be formed by irradiating a laser from the outer surface side of the outer layer 7 that covers the first reinforcing body 5 to a region where at least two of the multiple metal wires 51 that form the first reinforcing body 5 intersect and the surrounding region. The method for forming the fixing portion 53 by laser irradiation is not particularly limited, and an appropriate method can be selected depending on the material of the wires that form the first reinforcing body 5 and the shape and size of the fixing portion 53 to be formed, etc.

[0043] In this embodiment, the outer diameter and inner diameter of the second reinforcing body 6 are approximately constant from the tip to the base end. The outer diameter at the position where the fixing portion 53 is formed in the first reinforcing body 5 is larger than the inner diameter of the second reinforcing body 6. Because the outer diameter at the position where the fixing portion 53 is formed in the first reinforcing body 5 is larger than the inner diameter of the second reinforcing body 6, the second reinforcing body 6 is less likely to come off, thereby further improving the robustness of the entire catheter 1.

[0044] The catheter as a medical device according to the present disclosure has been described above with reference to the drawings. The present disclosure is not limited to the above-described embodiment, and various modifications are possible. The inner diameter of the inner layer, the outer diameter of the outer layer main body, and the outer diameter of the second reinforcing body may be constant, or each diameter may vary partially. A radiopaque marker may be disposed near the tip of the catheter, or the catheter may have a balloon.

[0045] <First Modification> A first modification of the catheter described in the above embodiment will be described below with reference to Fig. 3. In the catheter 1A of the first modification, the same components as those in the catheter 1 described above are designated by the same reference numerals, and their description will be omitted. Fig. 3 is an explanatory diagram showing the structure of the first modification of the catheter of the present disclosure, and the catheter 1A of the first modification differs from the catheter 1 described above in that the shape of the tip portion of the first reinforcing member 5A is different.

[0046] In this modification, the distal end of the first reinforcing body 5A located within the outer layer distal end portion 71 is provided with an expanded diameter section 52A whose inner diameter expands toward the distal end, and a constant diameter section 54A is provided on the distal side of the expanded diameter section 52A. Fixing sections 53A are provided at the distal end of the constant diameter section 54A and the distal end of the expanded diameter section 52A. By providing the expanded diameter section 52A and the fixing section 53A at the distal end of the first reinforcing body 5A located within the outer layer distal end portion 71, a structure is achieved that makes it difficult for the first reinforcing body 5A to detach from the outer layer 7, resulting in a catheter 1A that is highly robust and resistant to breakage.

[0047] The catheter 1A of this modification has a structure in which the inner diameter of the first reinforcing body 5A gradually increases from the base end to the tip end within the outer layer distal portion 71 and then remains constant, and differs from the previously described catheter 1 in that the expanded diameter portion 52A is not provided at the tip-most portion of the first reinforcing body 5A. The catheter 1A of this modification also differs from the previously described catheter 1 in that the fixing portions 53A are provided at multiple locations. In this way, by changing the locations of the expanded diameter portions 52A and the fixing portions 53A, it is possible to control the flexibility of the outer layer distal portion 71.

[0048] <Second Modification> A second modification of the catheter described in the above embodiment will be described below with reference to Fig. 4. In the catheter 1B of the second modification, the same components as those in the catheter 1 and catheter 1A described above are designated by the same reference numerals, and their description will be omitted. Fig. 4 is an explanatory diagram showing the structure of the second modification of the catheter of the present disclosure, and the catheter 1B of the second modification differs from the catheter 1 and catheter 1A described above in that the shape of the tip portion of the first reinforcing member 5B is different.

[0049] In this modification, the distal end of the first reinforcing body 5B located within the outer layer distal end portion 71 is provided with an expanded diameter section 52B whose inner diameter expands toward the distal end, a constant diameter section 54B is provided on the distal side of the expanded diameter section 52B, and a reduced diameter section 55B is provided on the distal side of the constant diameter section 521B. A fixing section 53B is provided at the distal end of the constant diameter section 54B and the distal end of the expanded diameter section 52B, but not at the distal end of the reduced diameter section 55B. By providing the expanded diameter section 52B and the fixing section 53B at the distal end of the first reinforcing body 5B located within the outer layer distal end portion 71, a structure is achieved that makes it difficult for the first reinforcing body 5B to detach from the outer layer 7, resulting in a catheter 1B that is highly robust and resistant to breakage.

[0050] The catheter 1B of this modification has a structure in which the inner diameter of the first reinforcing body 5B gradually increases from the base end to the tip end, then remains constant, and then gradually decreases within the outer layer tip portion 71, and differs from the catheter 1 described above in that the expanded diameter portion 52B is not provided at the tip-most portion of the first reinforcing body 5B. The catheter 1B of this modification also differs from the catheter 1 described above in that the fixing portion 53B is provided at multiple locations and is not provided at the tip of the first reinforcing body 5B. In this way, by changing the locations of the expanded diameter portion 52B and the fixing portion 53B, it is possible to control the flexibility of the outer layer tip portion 71.

Claims

1. A cylindrical inner layer (4); a cylindrical first reinforcing body (5) arranged outside the inner layer (4), with its tip located closer to the base end than the tip of the inner layer (4), and formed from a plurality of first wires (51), the first reinforcing body (5) having an expanding portion (52) at its tip where the inner diameter expands toward the tip and a fixing portion (53) at which at least two of the plurality of first wires (51) are fixed to each other; a cylindrical second reinforcing body (6) arranged outside the first reinforcing body (5), with its tip located closer to the base end than the tip of the first reinforcing body (5), and formed from at least one second wire (61); A medical device (1) comprising an outer layer (7) covering the inner layer (4), the first reinforcing body (5) and the second reinforcing body (6), the outer layer (7) having an outer layer tip portion (71) having a first hardness and covering the enlarged diameter portion (52) and the fixing portion (53), and an outer layer main body portion (72) located on the base end side of the outer layer tip portion (71) and having a second hardness lower than the first hardness.

2. A medical device according to claim 1, wherein the fastening portion (53) is provided on the enlarged portion (52) of the first reinforcement body (5).

3. A medical device according to claim 1 or 2, wherein the fastening portion (53) is located at the tip of the first reinforcement body (5).

4. A medical device according to any one of claims 1 to 3, wherein the fastening portion (53) is formed in a mass.

5. A medical device according to any one of claims 1 to 4, wherein the fixing portion (53) is formed in a substantially spherical shape.

6. A medical device according to any one of claims 1 to 5, wherein the outer layer distal portion (71) has a tapered portion (711) whose outer diameter decreases toward the distal end, and a straight portion (712) located on the proximal side of the tapered portion (711) and whose outer diameter is constant, and wherein the distal end of the first reinforcing body (5) is located within the straight portion (712).

7. A medical device according to any one of claims 1 to 6, wherein the outer layer tip portion (71) and the outer layer main body portion (72) are formed from the same type of resin material.

8. A medical device according to any one of claims 1 to 7, wherein the outer layer tip portion (71) and the outer layer main body portion (72) are formed from the same resin material.

9. A medical device according to any one of claims 1 to 8, wherein the outer diameter of the first reinforcing body (5) at the location where the fixing portion (53) is formed is larger than the inner diameter of the second reinforcing body (6).

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