Catheter

Abstract

To provide a catheter with improved pushability.SOLUTION: A catheter includes: an insertion part that has a hollow shaft and is at least partially inserted into the inside of a body; and an operation part that is provided in a further rear end side than the insertion part and is gripped by an operator. The operation part includes a metal lower-layer tube and a metal upper-layer tube covering an outer circumference of the lower-layer tube.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Catheters that are inserted into the body and used for treatment or diagnosis have been known for some time. Patent Document 1 describes a catheter that includes a metal tube having a spiral cut. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2011-506045 Summary of the Invention [Problem to be solved by the invention]

[0004] Catheters are inserted into the body by the surgeon and pushed to the target site inside the body, such as the lesion. There was room for improvement in the ability to transmit the force applied by the surgeon to the rear end of the catheter, known as pushability, to the tip of the catheter.

[0005] An object of the present invention is to improve the pushability of a catheter. [Means for solving the problem]

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

[0007] (1) One form of the present invention is a catheter comprising: an insertion portion having a hollow shaft, at least a portion of which is inserted into the body; and a control portion disposed rearward of the insertion portion and grasped by the surgeon. The control portion comprises a lower metal tube and an upper metal tube covering the outer periphery of the lower tube.

[0008] According to this configuration, the bending rigidity of the rear end portion of the catheter is increased, thereby improving the pushability of the catheter.

[0009] (2) In the catheter of the above embodiment, the wall thickness of the upper tube may be smaller than the wall thickness of the lower tube.

[0010] According to this configuration, the upper tube easily deforms along the surgeon's finger, allowing the surgeon to easily grasp the catheter.

[0011] (3) In the catheter of the above embodiment, the operation section may have a space formed between the outer periphery of the lower tube and the inner periphery of the upper tube.

[0012] According to this configuration, the upper tube easily deforms along the surgeon's finger, allowing the surgeon to easily grasp the catheter.

[0013] (4) In the catheter of the above embodiment, the tip of the upper tube may be located rearward of the tip of the lower tube.

[0014] According to this configuration, the step portion at the tip of the upper tube functions as a depth marker, making it easier for the surgeon to know the length of the catheter that has been inserted into the body.

[0015] The present invention can be realized in various aspects, for example, in the form of a guidewire, a method for manufacturing a guidewire, a method for manufacturing a catheter, an endoscope, a dilator, and the like. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an explanatory diagram illustrating the overall configuration of a catheter according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory view illustrating a longitudinal cross section of the rear end portion of the catheter of the first embodiment. [Diagram 3]FIG. 13 is an explanatory diagram illustrating a state in which an upper tube is recessed. [Figure 4] 4 is an explanatory diagram illustrating a cross section taken along line AA in FIG. 2 and a cross section taken along line BB in FIG. 3. [Diagram 5] FIG. 1 is an explanatory diagram illustrating a longitudinal cross section of a rear end portion of a conventional catheter. [Figure 6] FIG. 11 is an explanatory view illustrating a longitudinal cross section of the rear end portion of a catheter according to a second embodiment. [Figure 7] FIG. 11 is an explanatory view illustrating a longitudinal cross section of the rear end portion of a catheter according to a third embodiment. [Figure 8] FIG. 13 is an explanatory view illustrating a longitudinal cross section of the rear end portion of a catheter according to a fourth embodiment. [Figure 9] FIG. 13 is an explanatory view illustrating a longitudinal cross section of the rear end portion of a catheter according to a fifth embodiment. [Figure 10] FIG. 13 is an explanatory view illustrating a longitudinal cross section of the rear end portion of a catheter according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] First Embodiment FIG. 1 is an explanatory diagram illustrating the overall configuration of the catheter 1 of the first embodiment. FIG. 1 illustrates a part of the catheter 1 in a longitudinal section, but illustrates the outer shape, not the longitudinal section, of the covering member 41, covering member 42, lower layer tube 60, upper layer tube 80, fixing portion 85, fixing portion 86, protector tube 30, and hub 31 described later. The catheter 1 will be described with reference to FIG. 1 to FIG. 5. The size of each component of the catheter 1 shown in FIG. 1 to FIG. 5 is an example, and may be expressed on a scale different from the actual size. Hereinafter, the end portion of each component of the catheter 1 located on the tip side will be referred to as the "tip", and the portion including the "tip" and extending from the tip to the middle toward the rear end will be referred to as the "tip portion". Similarly, the end portion of each component located on the rear end side will be referred to as the "rear end", and the portion including the "rear end" and extending from the rear end to the middle toward the tip side will be referred to as the "rear end portion".

[0018] The catheter 1 is a medical device that is inserted into blood vessels or digestive organs and used for diagnosis or treatment. In this embodiment, the catheter 1 is a "balloon catheter" having a balloon 12, which will be described later, at its tip. However, the catheter 1 is not limited to a form having a balloon 12 at its tip, and can be embodied in various forms. For example, the catheter 1 may have a configuration for injecting a contrast agent or the like into the body. Alternatively, the catheter 1 may have a function of suctioning a thrombus generated in a blood vessel.

[0019] The catheter 1 includes an insertion section 2, which is provided at the tip side of the catheter 1 and is inserted into the body, and an operation section 3, which is provided at the rear end side of the catheter 1 and is held by the surgeon. At least a part of the insertion section 2 is inserted into the body. The operation section 3 is held when the surgeon pushes the catheter 1 into the body. The insertion section 2 includes a tip tip 10, an X-ray opaque marker 11, a balloon 12, a core wire 13, an inner shaft 20, an outer shaft 21, an outer middle shaft 22, a covering member 41, a covering member 42, and a part of the lower layer tube 60. The operation section 3 includes a protector tube 30, a hub 31, a part of the lower layer tube 60, and an upper layer tube 80. In this embodiment, the position of the boundary between the insertion section 2 and the operation section 3 in the longitudinal direction of the catheter 1 is the same as the position of the tip of the upper layer tube 80.

[0020] The distal tip 10 is a hollow member connected to the distal end of the balloon 12 and the distal end of the inner shaft 20. The distal tip 10 is located at the distal end of the catheter 1.

[0021] The radiopaque marker 11 is an annular member provided on the outer periphery of the inner shaft 20. The radiopaque marker 11 is made of a material having a low X-ray transmittance compared to other members constituting the catheter 1. In this embodiment, two radiopaque markers 11 are provided on the outer periphery of the inner shaft 20.

[0022] The balloon 12 is a member that can expand radially outward from the inner shaft 20. The balloon 12 is made of a thin film of resin formed into a cylindrical shape. The balloon 12 covers the outer periphery of the tip of the inner shaft 20. The balloon 12 has a liquid-tight space on the inside that communicates with the lumen of the outer shaft 21 described below. The balloon 12 expands when the fluid that passes through the lumen of the outer shaft 21 fills the liquid-tight space.

[0023] The core wire 13 is a metal wire extending along the longitudinal direction of the catheter 1. The tip end of the core wire 13 is provided inside the outer shaft 21, and the rear end is provided inside the outer middle shaft 22.

[0024] The inner shaft 20 is a hollow member extending along the longitudinal direction of the catheter 1. The inner shaft 20 is provided inside the outer shaft 21. The tip of the inner shaft 20 is connected to the tip tip 10. The rear end of the inner shaft 20 is located between the tip and rear ends of the outer shaft 21 and is connected to the side wall of the outer shaft 21. A lumen into which a guidewire GW or the like can be inserted is provided inside the inner shaft 20. The tip of the lumen communicates with the lumen provided in the tip tip 10, and the rear end of the lumen communicates with a guidewire port GP provided in the outer shaft 21, which will be described later.

[0025] The outer shaft 21 is a hollow member extending along the longitudinal direction of the catheter 1. The tip of the outer shaft 21 is connected to the rear end of the balloon 12. The rear end of the outer shaft 21 is connected to the tip of the outer middle shaft 22, not shown. A lumen is provided inside the outer shaft 21 for passing a fluid for expanding the balloon 12. The outer shaft 21 has a guidewire port GP on the side wall between the tip and base end of the outer shaft 21. The guidewire port GP is an opening formed in the side wall of the outer shaft 21 that connects the inside of the outer shaft 21 to the outside of the outer shaft 21.

[0026] The outer middle shaft 22 is a hollow member extending along the longitudinal direction of the catheter 1. The outer middle shaft 22 is located between the outer shaft 21 and the lower tube 60. The rear end of the outer middle shaft 22 is connected to the tip end of the covering member 41.

[0027] The protector tube 30 is a hollow member provided between the upper tube 80 and the hub 31. The front end of the protector tube 30 is connected to the upper tube 80, and the rear end is connected to the hub 31.

[0028] The hub 31 is a member provided at the rear end of the catheter 1 for connecting the catheter 1 to other medical devices or the like.

[0029] The covering member 41 and the covering member 42 are located at the rear end side of the catheter 1 and are thin resin members extending along the longitudinal direction of the catheter 1. The covering member 41 covers a part of the outer periphery 62 of the lower tube 60. The covering member 42 is located at the rear end side of the covering member 41 and covers a part of the outer periphery 62 of the lower tube 60. The rear end of the covering member 41 and the tip of the covering member 42 are spaced apart. Between the rear end of the covering member 41 and the tip of the covering member 42, the outer periphery 62 of the lower tube 60 is exposed. Between the rear end of the covering member 41 and the tip of the covering member 42, the part where the outer periphery 62 of the lower tube 60 is exposed is called a "depth marker D1". In this embodiment, the "depth marker" refers to a mark provided for the surgeon to confirm the length of the part of the catheter 1 inserted into the body during treatment. The material of the covering member 41 and the covering member 42 is not particularly limited, but for example, a resin such as PTFE can be used.

[0030] The lower tube 60 is a hollow metal member located at the rear end of the catheter 1 and extending along the longitudinal direction of the catheter 1. The tip of the lower tube 60 is connected to the rear end of the outer middle shaft 22, and the rear end extends to the inside of the protector tube 30.

[0031] The upper tube 80 is a hollow metal member that covers a part of the outer periphery 62 of the lower tube 60. The upper tube 80 is located between the covering member 42 and the protector tube 30. The tip of the upper tube 80 is fixed to the lower tube 60 by a fixing part 85, and the rear end of the upper tube 80 is fixed to the lower tube 60 by a fixing part 86. The fixing part 85 and the fixing part 86 can be formed by, for example, UV (ultraviolet) adhesion or laser welding. The vicinity of the step part 81 generated by the difference between the outer diameter of the upper tube 80 and the outer diameter of the lower tube 60 is called the "depth marker D2". The longitudinal length of the upper tube 80 is not particularly limited, but can be about 450 mm, for example, when the length from the tip of the catheter 1 to the protector tube 30 is about 1450 mm. Alternatively, the longitudinal length of the upper tube 80 can be set to any value between 200 mm and 700 mm. The upper tube 80 will be described in detail later.

[0032] The material of the lower tube 60 and the upper tube 80 is not particularly limited, but may be stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, platinum, gold, tungsten, etc.

[0033] As described above, the catheter 1 is provided with two depth markers (D1, D2). When the catheter 1 is inserted into the body, the surgeon can check the length of the portion of the catheter 1 that has been inserted into the body by checking the positions of the depth marker D1 and the depth marker D2. The distance from the tip of the catheter 1 to the depth marker D1 can be set to any value depending on the overall length of the catheter 1 and the use of the catheter 1. For example, when the length from the tip of the catheter 1 to the protector tube 30 is about 1450 mm, the distance from the tip of the catheter 1 to the depth marker D1 can be set to about 900 mm, and the distance from the tip of the catheter 1 to the depth marker D2 can be set to about 1000 mm. Alternatively, the distance from the tip of the catheter 1 to the depth marker D1 can be set to any value between 650 mm and 1150 mm, and the distance from the tip of the catheter 1 to the depth marker D2 can be set to any value between 750 mm and 1250 mm.

[0034] <Details of upper tube 80> Fig. 2 is an explanatory diagram illustrating a longitudinal section of the rear end portion of the catheter 1 of the first embodiment. Fig. 2 illustrates a longitudinal section of a portion of the catheter 1 surrounded by the frame line X illustrated in Fig. 1. As described above, the upper layer tube 80 covers a portion of the outer periphery 62 of the lower layer tube 60. In other words, a portion of the rear end side of the catheter 1 is formed of a two-layer metal tube.

[0035] The ease of pushing the catheter 1 can be evaluated by "pushability." In this embodiment, pushability refers to the ability to transmit the force of the surgeon pushing the rear end of the catheter 1 to the tip of the catheter 1. The bending rigidity of the rear end of the catheter 1 is increased by the two-layer metal tube (lower tube 60 and upper tube 80). The high bending rigidity of the rear end of the catheter 1 can improve pushability.

[0036] The thickness T2 of the upper tube 80 is smaller than the thickness T1 of the lower tube 60. The thickness T1 of the upper tube 80 is not particularly limited, but may be, for example, 20 μm to 50 μm. The thickness T2 of the lower tube 60 is not particularly limited, but may be, for example, 100 μm to 150 μm. For example, when the upper tube 80 and the lower tube 60 are made of the same material, the bending rigidity and hardness of the upper tube 80 are smaller than the bending rigidity and hardness of the lower tube 60, and the upper tube 80 can be deformed more easily than the lower tube 60. The upper tube 80 can be recessed toward the radial inside of the lower tube 60 by being grasped by the surgeon. In particular, when the thickness T2 of the upper tube 80 is 20 μm to 50 μm, the upper tube 80 can be easily deformed to fit the shape of the surgeon's finger, so that unevenness that fits the shape of the finger is formed on the outer periphery of the upper tube 80. The surgeon can easily push the catheter 1 forward by catching the unevenness with his / her fingers.

[0037] The outer periphery 62 of the lower tube 60 and the inner periphery 82 of the upper tube 80 are spaced apart from each other, and a space 90 is formed between the outer periphery 62 of the lower tube 60 and the inner periphery 82 of the upper tube 80. The space 90 is formed along the outer periphery 62 of the lower tube 60.

[0038] The upper tube 80 covers the outer periphery 62 of the lower tube 60, and the outer diameter of the catheter 1 increases by the outer diameter of the upper tube 80. A step 81 is formed near the tip of the upper tube 80 due to the difference in outer diameter between the upper tube 80 and the lower tube 60. However, in this embodiment, since the covering member 42 covers the outer periphery 62 of the lower tube 60, the step 81 is formed by the difference between the outer diameter of the upper tube 80 and the outer diameter of the covering member 42. As described above, the step 81 functions as a depth marker D2. The operator can visually confirm the position of the step 81 due to the visual difference in color, gloss, etc. between the lower tube 60 and the upper tube 80, or the visual difference in color, gloss, etc. between the covering member 42 and the upper tube 80. Furthermore, the operator can sense the position of the step 81 by touching the step 81 with a finger or the like. Therefore, the operator can easily confirm the position of the step 81. Furthermore, since the fixing portion 85 is provided near the step portion 81, the surgeon can more easily confirm the position of the depth marker D2 by improving the visibility of the fixing portion 85. For example, when the fixing portion 85 is UV (ultraviolet) adhesive, the visibility of the fixing portion 85 can be improved by coloring the adhesive.

[0039] 3 is an explanatory diagram illustrating a state in which the upper tube 80 is depressed. As described above, since the upper tube 80 is thinner than the lower tube 60, the upper tube 80 can deform radially inward (in the direction of arrow A1 or arrow A2 in FIG. 3) more easily than the lower tube 60. When the upper tube 80 is depressed, the space 90 becomes smaller, and when the upper tube 80 is further depressed, the inner circumference 82 of the upper tube 80 and the outer circumference 62 of the lower tube 60 come into contact with each other.

[0040] Fig. 4 is an explanatory diagram illustrating the AA cross section of Fig. 2 and the BB cross section of Fig. 3. Fig. 4(A) and Fig. 4(B) illustrate cross sections of the rear end of the catheter 1. Fig. 4(A) illustrates a state in which no load is applied to the upper layer tube 80, and the outer periphery 62 of the lower layer tube 60 and the inner periphery 82 of the upper layer tube 80 are not in contact. Fig. 4(B) illustrates a state in which a load is applied to the upper layer tube 80 in the directions of arrows A1 and A2, and a part of the outer periphery 62 of the lower layer tube 60 and a part of the inner periphery 82 of the upper layer tube 80 are in contact.

[0041] A case where a force toward the radial inside of the lower tube 60 is applied to the upper tube 80 is, for example, a case where an operator grasps the upper tube 80 and operates the catheter 1. When the operator presses the upper tube 80 with his / her finger, the upper tube 80 is recessed toward the radial inside of the lower tube 60, and the outer periphery of the upper tube 80 is deformed according to the shape of the operator's finger. This makes it easier for the operator to push the catheter 1. The upper tube 80 may be configured to be plastically deformed by the operator's grasp and not to return to the shape before deformation (outer diameter before deformation) even when the operator stops grasping the upper tube 80. Alternatively, the upper tube 80 may be configured to be elastically deformed by the operator's grasp and to return to the shape before deformation (outer diameter before deformation) when the operator stops grasping the upper tube 80.

[0042] According to the catheter 1 of the present embodiment described above, the catheter 1 includes a lower layer tube 60 and an upper layer tube 80 in the operation section 3. The two-layer metal tube increases the bending rigidity of the operation section 3 provided at the rear end side of the catheter 1, thereby improving the pushability of the catheter 1. This allows the surgeon to easily push the catheter 1 into the body. In particular, when the tip of the catheter 1 passes through a lesion formed in a blood vessel, the improved pushability of the catheter 1 improves the ability to pass through the lesion.

[0043] For example, if the upper layer tube 80 and the lower layer tube 60 are provided at the site (insertion section 2) of the catheter 1 that is inserted into the body, the outer diameter of the tip side of the catheter 1 will be large, which may make it difficult to insert the catheter 1 into a thin blood vessel or the like. In addition, the large outer diameter of the insertion section 2 of the catheter 1 may make it difficult to perform the "kissing balloon technique" in which multiple balloon catheters are inserted into the body at the same time. However, the upper layer tube 80 and the lower layer tube 60 of the catheter 1 are provided in the operation section 3 at the rear end side of the catheter 1, more rearward than the depth markers (D1, D2), and therefore the catheter 1 will not be inserted into a blood vessel or the like. This allows the outer diameter of the tip side of the catheter 1 to be kept small, making it easy to insert the catheter 1 into a blood vessel or the like.

[0044] The thickness T2 of the upper tube 80 is smaller than the thickness T1 of the lower tube 60. As a result, the bending rigidity and hardness of the upper tube 80 are smaller than those of the lower tube 60, and the upper tube 80 is more easily deformed than the lower tube 60. In addition, the inner circumference 82 of the upper tube 80 and the outer circumference 62 of the lower tube 60 are spaced apart, and a space 90 is provided between the inner circumference 82 of the upper tube 80 and the outer circumference 62 of the lower tube 60. As a result, when the surgeon grasps the upper tube 80 for operation, the outer circumference of the upper tube 80 deforms according to the shape of the surgeon's finger, and when the surgeon applies force to the upper tube 80, the inner circumference 82 of the upper tube 80 comes into contact with the outer circumference 62 of the lower tube 60. This allows the surgeon to easily grasp the catheter 1, and the pushability of the catheter 1 can be improved.

[0045] FIG. 5 is an explanatory diagram illustrating a longitudinal section of the rear end of a conventional catheter 1Z. The catheter 1Z is different from the catheter 1 of this embodiment in that it does not include an upper layer tube 80 (FIG. 2). The catheter 1Z includes a lower layer tube 60 and a covering member (41, 42, 43) that covers the outer periphery 62 of the lower layer tube 60. On the other hand, the catheter 1Z does not include a two-layer metal tube configuration including the lower layer tube 60 and the upper layer tube 80. As a result, the bending rigidity of the rear end side of the catheter 1Z is small, and there is room for improvement in pushability. In addition, since the catheter 1Z does not include the upper layer tube 80, the outer shape of the catheter 1Z does not deform along the operator's finger, and since the catheter 1Z has a relatively small outer diameter, it may be difficult for the operator to grasp the catheter 1. On the other hand, as described above, the catheter 1 of this embodiment has a high bending rigidity at the rear end and is equipped with an upper tube 80 that deforms along the surgeon's finger, thereby improving pushability compared to the conventional catheter 1Z and allowing the surgeon to easily grasp the catheter 1.

[0046] As shown in Fig. 4, the tip of the upper tube 80 is located rearward of the tip of the lower tube 60, and the catheter 1 has a step 81 caused by the difference in outer diameter between the upper tube 80 and the lower tube 60. The step 81 functions as a depth marker D2. In addition to visually confirming the depth marker D2, the surgeon can also confirm the depth marker D2 by touch. This can improve the efficiency of treatment and shorten the treatment time.

[0047] <Second embodiment> 6 is an explanatory diagram illustrating a longitudinal cross section of the rear end portion of a catheter 1B of the second embodiment. The catheter 1B differs from the catheter 1 of the first embodiment in that the thickness T2b of the upper layer tube 80B is greater than the thickness T1b of the lower layer tube 60B. Of the configuration of the catheter 1B, the description of the configuration common to the catheter 1 will be omitted.

[0048] In the catheter 1B, the thickness T2b of the upper tube 80B is greater than the thickness T1b of the lower tube 60B. For example, the upper tube 80B can be made of a material that is more flexible than the material of the lower tube 60B, so that the upper tube 80B can be configured to deform more easily than the lower tube 60B. The catheter 1B can also improve the pushability of the catheter 1B.

[0049] <Third embodiment> 7 is an explanatory diagram illustrating a vertical cross section of the rear end portion of a catheter 1C of the third embodiment. The catheter 1C differs from the catheter 1 of the first embodiment in that the outer periphery 62 of the lower tube 60 and the inner periphery 82 of the upper tube 80C are not separated from each other, and a space 90 (FIG. 2) is not formed. A description of the configuration of the catheter 1C that is common to the catheter 1 will be omitted.

[0050] In the catheter 1C, no space 90 is formed between the outer periphery 62 of the lower tube 60 and the inner periphery 82 of the upper tube 80C, and the outer periphery 62 of the lower tube 60 and the inner periphery 82 of the upper tube 80C are fixed in a contacting state. The catheter 1C can also improve the pushability of the catheter 1C.

[0051] <Fourth embodiment> 8 is an explanatory diagram illustrating a longitudinal cross section of the rear end portion of a catheter 1D of the fourth embodiment. The catheter 1D differs from the catheter 1 of the first embodiment in that it includes a covering member 44. Of the configuration of the catheter 1D, the description of the configuration common to the catheter 1 will be omitted.

[0052] The covering member 44 is a thin resin member that covers a part of the outer periphery of the upper tube 80. The tip of the covering member 44 is provided on the rear end side of the tip of the upper tube 80. Between the tip of the covering member 44 and the tip of the upper tube 80, the outer periphery of the upper tube 80 and the fixing part 85 are exposed. In this embodiment, the step part 81, the part of the upper tube 80 that is not covered by the covering member 44, and the fixing part 85 function as the depth marker D2. The surgeon can easily confirm the position of the depth marker D2 due to the visual difference in color, gloss, etc. between the outer periphery of the covering member 44 and the outer periphery of the upper tube 80 and the outer periphery of the fixing part 85. The catheter 1D can also improve the pushability of the catheter 1D.

[0053] <Fifth embodiment> 9 is an explanatory diagram illustrating a vertical cross section of the rear end portion of a catheter 1E of the fifth embodiment. The catheter 1E is different from the catheter 1D of the fourth embodiment in that the fixing portion 85E and the fixing portion 86E are provided between the outer periphery 62 of the lower layer tube 60 and the inner periphery 82 of the upper layer tube 80, and are not provided on the outer periphery of the upper layer tube 80. Descriptions of the configuration of the catheter 1E that are common to the catheter 1D will be omitted.

[0054] The fixing parts 85E and 86E are provided between the outer periphery 62 of the lower tube 60 and the inner periphery 82 of the upper tube 80. The fixing parts (85E, 86E) are not provided on the outer periphery of the upper tube 80. In this embodiment, the step portion 81 and the outer periphery of the upper tube 80 that is not covered by the covering member 44 function as the depth marker D2. The catheter 1E can also improve the pushability of the catheter 1E.

[0055] Sixth Embodiment 10 is an explanatory diagram illustrating a vertical cross section of the rear end of a catheter 1F of the sixth embodiment. The catheter 1F differs from the catheter 1 of the first embodiment in that the rear end of a covering member 42F is spaced from the tip of the upper tube 80 and that covering members 45 and 46 are provided. Of the configuration of the catheter 1F, the description of the configuration common to the catheter 1 will be omitted.

[0056] The rear end of the covering member 42F is spaced apart from the tip of the upper tube 80, and the outer periphery of the lower tube 60 is exposed between the rear end of the covering member 42F and the tip of the upper tube 80. In this embodiment, the lower tube 60 exposed between the rear end of the covering member 42F and the tip of the upper tube 80 functions as a depth marker D2. The covering member 45 is a thin resin member that covers a part of the outer periphery of the upper tube 80. The covering member 46 is a thin resin member that is provided on the rear end side of the covering member 45 and covers a part of the outer periphery of the upper tube 80. The rear end of the covering member 45 and the tip of the covering member 46 are spaced apart, and the outer periphery of the upper tube 80 is exposed. The outer periphery of the upper tube 80 that is exposed and not covered by the covering members (45, 46) functions as a depth marker D3. The catheter 1F can also improve the pushability of the catheter 1F.

[0057] <Modification> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0058] <Variation 1> In the catheters (1, 1B, 1C, 1D, 1E, 1F) of the first to sixth embodiments, the position of the boundary between the insertion section 2 and the operation section 3 in the longitudinal direction of the catheter (1, 1B, 1C, 1D, 1E, 1F) is the same as the position of the tip of the upper tube (80, 80B, 80C). However, the position of the boundary between the insertion section 2 and the operation section 3 in the longitudinal direction of the catheter (1, 1B, 1C, 1D, 1E, 1F) can be determined arbitrarily, and for example, the position of the boundary between the insertion section 2 and the operation section 3 can be the position of the depth marker D1 (FIG. 1).

[0059] <Variation 2> In the catheters (1, 1B, 1C, 1D, 1E, 1F) of the first to sixth embodiments, the tip of the upper tube (80, 80B, 80C) is provided on the rear side of the tip of the lower tube (60, 60B). However, the tip of the upper tube (80, 80B, 80C) does not have to be provided on the rear side of the tip of the lower tube (60, 60B). For example, the tip of the upper tube (80, 80B, 80C) and the tip of the lower tube (60, 60B) may be provided at the same position in the longitudinal direction of the catheter (1, 1B, 1C, 1D, 1E, 1F), and the tip of the upper tube (80, 80B, 80C) may be provided on the distal side of the tip of the lower tube (60, 60B). [Explanation of symbols]

[0060] 1. Catheter 10…Tip 11…Radiopaque marker 12. Balloon 13…Core wire 20…Inner shaft 21…Outer shaft 22…Outer middle shaft 30…Protector tube 31…Hub 41...Covering member 42...Covering member 60…Lower tube 62…Outer circumference of lower tube 80…Upper tube 81...Step 82…Inner circumference of upper tube 85…Fixed part 86…Fixed part 90…Space part D1…Depth marker D2…Depth marker

Claims

1. A catheter, an insertion portion having a hollow shaft and at least a portion of which is inserted into the body; an operation section provided on the rear end side of the insertion section and grasped by an operator, The operating unit includes a metal lower tube and A catheter comprising: an upper metal tube that covers the outer periphery of the lower tube.

2. 10. The catheter of claim 1, A catheter in which the wall thickness of the upper tube is smaller than the wall thickness of the lower tube.

3. The catheter according to claim 1 or 2, A catheter, wherein the operating section has a space formed between the outer periphery of the lower tube and the inner periphery of the upper tube.

4. The catheter according to claim 1 or 2, A catheter in which the tip of the upper tube is located closer to the rear end than the tip of the lower tube.

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