Method of manufacturing catheter, and catheter

Abstract

To provide a method of manufacturing a catheter and a catheter that is prevented from varying in thickness in regions of different diameters even when diameter shrinking processing is performed on a tube.SOLUTION: A method of manufacturing a catheter 10 having a resin tube body with a tip end and base end, includes the steps of: preparing an unprocessed tube 300 in which a first tube 301 having a constant thickness and a second tube 302 having a thickness larger than the first tube 301 are arranged adjacent to each other in a longitudinal axial direction; and forming the tube body by shrinking the diameter of the second tube 302 in the unprocessed tube 300 to make an outer diameter of the processed second tube 302 smaller than an outer diameter of the first tube 301, and to make a thickness of the processed second tube 302 the same as a thickness of the first tube 301.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a catheter that is inserted into a biological lumen for treatment, and to the catheter. [Background technology]

[0002] Intravascular treatment is a method for treating lesions such as stenosis and blockage in blood vessels, in which a device is inserted percutaneously into the blood vessel to perform treatment from within the blood vessel. In intravascular treatment, a catheter is used to deliver a diagnostic contrast agent, a guide wire, or a treatment site to the lesion.

[0003] For example, in the treatment of myocardial infarction and angina pectoris, a catheter is used to place a stent in the affected area (stenosis) of the coronary artery to secure space within the coronary artery, and a similar method is sometimes used to improve stenosis in other blood vessels, bile ducts, tracheas, esophagus, urethra, and other biological lumens. Stents are classified into balloon-expandable stents and self-expandable stents based on their function and placement method.

[0004] A balloon-expandable stent does not have an expansion function itself, and after reaching the target site, it is expanded by a balloon and is fixed in place within the lumen. In contrast, a self-expandable stent has an expansion function itself, and is housed in a catheter in a pre-reduced state. After reaching the target site, a self-expandable stent is released from the catheter, expands by its own expansion force, and is fixed in place within the lumen.

[0005] Patent Document 1 describes a rapid exchange type (RX) stent delivery system that delivers a self-expanding stent to a target site in a lumen and fixes the self-expanding stent in close contact with the lumen. The catheter constituting the stent delivery system of Patent Document 1 is formed so that the outer diameter of the tip end that houses the stent is larger than the outer diameter of the base end, and has a tapered section between the tip end and the base end that expands in diameter toward the tip side. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5697935 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to form a tube having different outer diameters at the tip and base ends from an unprocessed tube having a constant outer diameter and wall thickness, it is possible to perform a diameter reduction process on the portion that will become the base end with the smaller outer diameter. The diameter reduction process can be performed by inserting the unprocessed tube into a mold having an inner diameter smaller than the outer diameter of the unprocessed tube, and stretching it in the longitudinal direction while heating it with the mold. In this case, the wall thickness of the base end that has been subjected to the diameter reduction process is smaller than that before the process, but the wall thickness of the unreduced tip end remains the same as before the process, so the wall thickness of the tube changes along the longitudinal direction. In the base end where the wall thickness has been reduced, there is a possibility that local changes in physical properties may occur, which may affect the tensile strength of the tube, etc.

[0008] The present invention has been made to solve the above-mentioned problems, and has an object to provide a manufacturing method for a catheter in which the wall thickness does not change in areas of different diameters even when the tube is subjected to diameter reduction processing, and the catheter. [Means for solving the problem]

[0009] To achieve the above-mentioned object, (1) a method for manufacturing a catheter is a method for manufacturing a catheter having a tubular body formed of resin and having a tip and a base end, the method comprising the steps of: preparing an unprocessed tube in which a first tube having a certain wall thickness and a second tube having a wall thickness greater than that of the first tube are arranged adjacent to each other along a longitudinal direction; and performing a diameter reduction process on the second tube of the unprocessed tube to make the outer diameter of the processed second tube smaller than the outer diameter of the first tube and to make the wall thickness of the processed second tube the same as that of the first tube, thereby forming the tubular body.

[0010] (5) A catheter for achieving the above-mentioned object is a catheter comprising a resin tubular body having a tip and a base end, the tubular body comprising a first region and a second region at the base end of the first region, the outer diameter of the second region being smaller than the outer diameter of the first region, at least a portion of the second region having a tapered portion whose outer diameter decreases from the tip to the base end, the resin forming the second region having a greater hardness than the resin forming the first region, and the tapered portion having a greater hardness than the resin forming the first region. Effect of the Invention

[0011] The manufacturing method of the catheter (1) configured as described above can make the wall thickness of the second tube the same as that of the first tube after the second tube is reduced in diameter by stretching it in the longitudinal direction. This prevents the wall thickness from varying in areas of different diameters of the tubular body, and prevents local changes in physical properties.

[0012] (2) In the method for manufacturing a catheter according to (1) above, the unprocessed tube may include a reinforcing member having a repeating structure formed of metal wires over the entire length from the distal end to the proximal end, thereby increasing the tensile strength of the resulting tubular body.

[0013] (3) In the method for manufacturing a catheter according to (1) or (2) above, the second tube of the unprocessed tube may be made of a resin having a harder resin than the first tube, thereby increasing the hardness and tensile strength of the resulting tubular body toward the base end.

[0014] (4) In any of the catheter manufacturing methods (1) to (3) above, the second tube of the unprocessed tube may have an outer diameter larger than that of the first tube. This allows the first tube and the second tube to have the same inner diameter, and makes it easy to insert a core material into the unprocessed tube for diameter reduction in a mold.

[0015] The catheter (5) constructed as described above has a high hardness on the proximal end side of the tubular body, and therefore can have a high tensile strength.

[0016] (6) In the catheter of (5) above, the second region may have an inner diameter smaller than the inner diameter of the first region, thereby making it possible to reduce the change in thickness between the first region and the second region and the change in physical properties along the longitudinal axis.

[0017] (7) In the catheter of (5) or (6) above, the first region and at least a part of the second region may have the same thickness. This makes it possible to prevent local changes in physical properties and suppress breakage because the thickness is constant across the first region and the second region, which have different outer diameters of the tubular body.

[0018] (8) In any of the catheters described above in (5) to (7), the tubular body may have a plurality of layers in a wall thickness direction, and an inner layer of the tubular body may have a resin different from an outer layer of the tubular body. This makes it possible to achieve both flexibility of the tubular body and reduction in friction of a device inserted therethrough.

[0019] (9) In the catheter of any one of (5) to (8) above, the tubular body may have a reinforcing member extending from the first region to the second region, thereby increasing the strength of the tubular body.

[0020] (10) In the catheter of any one of (5) to (9) above, the tubular body may have a pulling wire fixed to a proximal end thereof, and the tubular body may be moved toward the proximal end by being pulled by the pulling wire, thereby allowing the tubular body to be used as a sheath for covering a stent.

[0021] (11) The catheter of (10) may further include an inner tube housed inside the tubular body, a stent disposed on an outer surface of a distal end of the inner tube, a proximal outer tube housed in the movable tubular body, and an operating section disposed on the proximal side of the proximal outer tube and fixed to the pulling wire, thereby enabling the catheter to be used as a stent placement system. [Brief description of the drawings]

[0022] [Figure 1] 1 is a front view showing an entire catheter according to an embodiment of the present invention. [Diagram 2] 1A and 1B are cross-sectional views showing the distal end of a catheter, in which FIG. 1A shows the state before the stent is deployed, and FIG. 1B shows the state during the stent deployment. [Diagram 3] 4 is an enlarged cross-sectional view of the first sheath near the boundary between the first region and the second region. FIG. [Figure 4] FIG. 4 is a partial front view of the first sheath reinforcement in the first region. [Diagram 5] FIG. 4 is a partial front view of the first sheath reinforcement in the second region. [Figure 6] 4 is an enlarged cross-sectional view of the vicinity of the boundary between the third region and the fourth region of the second sheath. FIG. [Figure 7]FIG. 11 is a cross-sectional view showing the manufacturing process of the first sheath, in which (a) shows the first tube and the second tube adjacent to each other, (b) shows the state in which a core material has been inserted into the tube, (c) shows the state in the middle of inserting the tube into a mold, and (d) shows the state after the tube has been inserted into the mold. [Figure 8] FIG. 11 is a cross-sectional view showing the tip side of a catheter according to a modified example. [Figure 9] 4 is an enlarged cross-sectional view of the vicinity of the boundary between the first region and the second region and the vicinity of the boundary between the second region and the fifth region of the sheath. FIG. [Figure 10] FIG. 11 is a cross-sectional view showing the manufacturing process of a sheath, in which (a) shows the first tube and the second tube adjacent to each other, (b) shows the tube with a core material inserted being inserted into a mold, (c) shows the second tube and the third tube adjacent to each other, and (d) shows the tube with a core material inserted into a second mold. [Figure 11] 10A and 10B are enlarged cross-sectional views of a first sheath according to a modified example, in which (a) shows a state in which the first tube and the second tube are adjacent to each other in an unprocessed tube, and (b) shows a state after diameter reduction processing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that dimensions in the drawings may be exaggerated and may differ from actual dimensions for convenience of explanation. In addition, in this specification and the drawings, components having substantially the same functions are given the same reference numerals to avoid duplicated explanation. In this specification, the side inserted into a lumen is referred to as the "distal side" and the hand side used for operation is referred to as the "base side".

[0024] The catheter 10 according to this embodiment is for placing a stent 20, which is a medical deployable object, in a narrowed or blocked area that occurs in a blood vessel, bile duct, trachea, esophagus, urethra, or other biological lumen to maintain the patency of the biological lumen. The catheter 10 is of the RX (Rapid Exchange) type, in which a guidewire 200 is inserted only at the tip side.

[0025] 1 and 2, the catheter 10 includes a stent 20, an outer tube 30 that houses the stent 20, an inner tube 40 that is disposed inside the outer tube 30, and a proximal shaft 70 that is disposed on the proximal side of the outer tube 30. The catheter 10 further includes a traction wire 80 for traction of the outer tube 30, and an operation section 110 that is disposed at the proximal end of the catheter 10.

[0026] The outer tube 30 includes a sheath 33 that houses the stent 20, and a proximal outer tube 32 that is located on the proximal side of the sheath 33. An inner tube 40 is disposed inside the sheath 33 and the proximal outer tube 32. The sheath 33 is movable toward the proximal side relative to the proximal outer tube 32. The sheath 33 includes a first sheath 34 and a second sheath 35. The stent 20, which has been reduced in diameter, is disposed inside the first sheath 34.

[0027] The first sheath 34 includes a first region 151 on the distal end side and a second region 152 on the proximal end side. The second region 152 has an outer diameter and an inner diameter smaller than those of the first region 151.

[0028] The second sheath 35 has an outer diameter and an inner diameter smaller than those of the first region 151 of the first sheath 34. The tip of the second sheath 35 is located on the outer surface of the second region 152 of the first sheath 34 and is covered with the connection tube 60, and the first sheath 34 and the second sheath 35 are connected by fusing and fixing the connection tube 60 by heating or the like. The connection tube 60 may be fixed by an adhesive or the like.

[0029] The second sheath 35 includes a third region 161 on the distal end side and a fourth region 162 on the proximal end side. The fourth region 162 has an outer diameter and an inner diameter smaller than those of the third region 161.

[0030] The third region 161 of the second sheath 35 has an outer diameter smaller than the inner diameter of the proximal outer tube 32, and the proximal side portion is located inside the proximal outer tube 32. When the sheath 33 moves toward the proximal side relative to the proximal outer tube 32, the second sheath 35 slides on the inner surface of the proximal outer tube 32 and can enter the inside of the proximal outer tube 32.

[0031] The pulling wire 80 is fixed to the fourth region 162 of the second sheath 35 which is the base end of the sheath 33. The pulling wire 80 is located on the outer surface of the fourth region 162 which is the base end of the second sheath 35, and is fixed to the second sheath 35 by being covered with the wire fixing tube 65 and fixed with an adhesive or the like. Note that the pulling wire 80 may be fixed by being covered with the wire fixing tube 65 and fused by heating or the like.

[0032] The proximal outer tube 32 is a tube capable of receiving therein the second sheath 35 that moves toward the proximal side.

[0033] The outer diameter of the outer tube 30 is not particularly limited, but is, for example, 0.5 to 10.0 mm, and preferably 1.0 to 5.0 mm. The inner diameter of the outer tube 30 is not particularly limited, but is, for example, 0.4 to 9.0 mm, and preferably 0.8 to 4.5 mm. The axial length of the outer tube 30 is not particularly limited, but is, for example, 10 to 250 mm, and preferably 20 to 100 mm.

[0034] As shown in Fig. 3, the first sheath 34 includes a first sheath tube 150 made of resin and a first sheath reinforcing body 157 having a repeating structure 159 made of metal wires 158. The first sheath tube 150 has an outer layer 150a made of a flexible resin and an inner layer 150b made of a low-friction resin. The first sheath reinforcing body 157 is located between the outer layer 150a and the inner layer 150b. The wires 158 can be made of stainless steel, gold, platinum, silver, iridium, tungsten, tantalum, or an alloy thereof.

[0035] The first sheath 34 has a first region 151 whose outer diameter is larger than the outer diameter of the second region 152, and between the first region 151 and the second region 152 is a first tapered portion 153 which is inclined so that the outer diameter becomes smaller from the tip side toward the base side.

[0036] The first sheath reinforcing body 157 extends over the entire length from the distal end to the proximal end of the first sheath 34. That is, in the first sheath reinforcing body 157, the repeating structure 159 extends over the first region 151, the first tapered portion 153, and the second region 152.

[0037] The first sheath 34 is formed so that the thickness T1 in the first region 151, the thickness T2 in the second region 152, and the thickness T3 in the first tapered portion 153 are the same. This prevents a sudden change in the physical properties of the first sheath 34 along the longitudinal direction.

[0038] 4, the first sheath reinforcement 157 in the first region 151 has a repeating structure 159 in which wires 158 are braided in a mesh shape so as to cross each other. The pitch of the repeating structure 159 in the first region 151 is P1, and the inclination angle of the wires 158 with respect to the longitudinal direction is α1.

[0039] 5, the first sheath reinforcement 157 in the second region 152 has a repeating structure 159 similar to that of the first region 157, with a pitch of P2 and an inclination angle of the wires 158 with respect to the longitudinal direction of the wires 158 being α2. The pitch P2 of the repeating structure 159 in the second region 152 is larger than the pitch P1 of the repeating structure 159 in the first region 151. Also, the inclination angle α2 of the wires 158 in the second region 152 is smaller than the inclination angle α1 of the wires 158 in the first region 151.

[0040] The pitch P3 of the repeating structures 159 in the first tapered portion 153 is larger than the pitch P1 in the first region 151 and smaller than the pitch P2 in the second region 152.

[0041] 6, the second sheath 35 includes a second sheath tube 160 made of resin and a second sheath reinforcing member 167 having a repeating structure 169 formed of metal wires 168. The second sheath tube 160 includes an outer layer 160a made of a flexible resin and an inner layer 160b made of a low-friction resin. The second sheath reinforcing member 167 is located between the outer layer 160a and the inner layer 160b.

[0042] The second sheath 35 has a third region 161 whose outer diameter is larger than the outer diameter of a fourth region 162, and between the third region 161 and the fourth region 162 is a second tapered portion 163 which is inclined so that the outer diameter becomes smaller from the tip side to the base side.

[0043] The second sheath reinforcing body 167 extends over the entire length from the distal end to the proximal end of the second sheath 35. That is, the second sheath reinforcing body 167 extends continuously over the third region 161, the second tapered portion 163, and the fourth region 162.

[0044] The repeating structure 169 of the second sheath reinforcing body 167 is a mesh-like braided structure similar to the repeating structure 159 of the first sheath reinforcing body 157. The pitch P5 of the repeating structure 169 in the fourth region is larger than the pitch P4 of the repeating structure 169 in the third region. In addition, the pitch P6 of the repeating structure 169 in the second tapered portion 163 is larger than the pitch P4 in the third region 161 and smaller than the pitch P5 in the fourth region 162.

[0045] The pulling wire 80 fixed to the base end of the second sheath 35 is fixed in the range of the fourth region 162, which is the fixing region. Since the second sheath reinforcing body 167 extends in the fourth region 162, the pulling wire 80 is fixed in the fixing region in which the second sheath reinforcing body 167 extends.

[0046] The second sheath 35 is formed so that the thickness of the third region 161, the thickness of the fourth region 162, and the thickness of the second tapered portion 163 are the same. This prevents a sudden change in the physical properties of the second sheath 35 along the longitudinal axis direction.

[0047] The material constituting the outer layer of the sheath 33 and the proximal outer tube 32 is not particularly limited, but is preferably a material that has hardness and flexibility, such as nylon, polyester, or fluororesin. The material constituting the inner layer is preferably a fluororesin. Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

[0048] 2, the inner tube 40 is a tubular body in which a guidewire lumen 41 is formed on the distal end side of the catheter 10. The inner tube 40 is equipped with a distal tip 44 fixed to the distal end, a distal marker 45, and a proximal marker 46. The inner tube 40 and the distal tip 44 are aligned in the axial direction and form a common guidewire lumen 41.

[0049] At least a portion of the inner tube 40 is located inside the outer tube 30, and penetrates the inside of the stent 20 disposed inside the outer tube 30. The tip of the inner tube 40 is located on the tip side of the outer tube 30.

[0050] The outer diameter of the inner tube 40 is not particularly limited, but is, for example, 0.15 to 3.0 mm, and preferably 0.3 to 1.5 mm. The inner diameter of the inner tube 40 is not particularly limited, but is, for example, 0.1 to 2.0 mm, and preferably 0.2 to 1.0 mm. The axial length of the inner tube 40 is not particularly limited, but is, for example, 50 to 2000 mm, and preferably 100 to 1000 mm.

[0051] The material of the inner tube 40 is not particularly limited, but for example, polyether ether ketone (PEEK), nylon, polyimide, etc. can be suitably used.

[0052] The distal tip 44 constitutes the distal end of the inner tube 40. The guidewire lumen 41 opens at a distal opening 47 formed at the distal end of the distal tip 44. The distal tip 44 may be formed integrally with the inner tube 40. The base end surface of the distal tip 44 contacts or is adjacent to the distal end surface of the first sheath 34 that houses the stent 20.

[0053] The distal tip 44 is preferably made of a flexible material, such as nylon elastomer, polyester elastomer, urethane elastomer, etc. The distal tip 44 may be made of a material containing a contrast medium.

[0054] The pulling wire 80 is a wire for pulling the sheath 33 toward the base end side to release the stent 20 from the sheath 33. One or more pulling wires 80 (two in this embodiment) are provided. The base end side of the pulling wire 80 is fixed to an operating unit 112 of the operation unit 110 described later. The tip side of the pulling wire 80 is fixed to the base end part of the second sheath 35.

[0055] A wire or a twisted wire may be suitably used as the pulling wire 80. The thickness of the pulling wire 80 is not particularly limited, but is, for example, 0.05 to 1.0 mm, and preferably 0.1 to 0.5 mm. The surface of the pulling wire 80 is covered with a fluorine-based resin, which is a low-friction material.

[0056] The constituent material of the traction wire 80 is not particularly limited, but examples thereof include stainless steel wire (preferably high tensile stainless steel for springs), piano wire (preferably nickel-plated or chrome-plated piano wire), wires made of various metals such as superelastic alloy wire, Ni-Ti alloy, Cu-Zn alloy, Ni-Al alloy, tungsten, tungsten alloy, titanium, titanium alloy, cobalt alloy, and tantalum, and relatively high rigidity polymeric materials such as polyamide, polyimide, ultra-high molecular weight polyethylene, polypropylene, and fluororesin, or an appropriate combination of these.

[0057] The stent 20 is formed in a generally cylindrical shape, and is housed in the first sheath 34 in a state compressed toward the central axis, as shown in Fig. 2. When the stent 20 is pushed out from the opening on the distal end side of the first sheath 34, the stress load is removed, the stent 20 expands, and the stent returns to its shape before compression. The shape of the stent 20 is not limited as long as it is a so-called self-expanding stent. As an example, the stent 20 may be formed into a single generally cylindrical shape by connecting a plurality of annular portions formed into an annular shape while bending.

[0058] A superelastic alloy is preferably used as the material for the stent 20. The superelastic alloy referred to here is generally called a shape memory alloy, and is one that exhibits superelasticity at least at the body temperature (around 37°C). As the shape memory alloy, Ni-Ti alloy, Cu-Al-Ni alloy, Cu-Zn-Al alloy, etc. can be preferably used.

[0059] As shown in FIG. 1, the operation unit 110 includes an operation main body 111, an operating unit 112, and an anti-kink protector 113.

[0060] The operation main body 111 is a portion that is held by the surgeon. The operation main body 111 accommodates a mechanism for pulling the pulling wire 80, including a part of the operating unit 112, inside.

[0061] The operating unit 112 is a portion where a user performs a pulling operation of the pulling wire 80. The operating unit 112 includes a dial 117 that is operated by an operator, and can rotate relative to the operation main body 111 about a rotation axis 119.

[0062] The dial 117 is a part that is rotated by the surgeon, is formed in a disk shape, and is disposed in the operation body 111 so as to be partially exposed from the operation body 111. The part of the dial 117 that is exposed from the operation body 111 is the part that the surgeon operates. It is preferable that the surface part that the surgeon may touch when operating the dial 117 is a non-slip surface. For example, it is preferable that the outer peripheral surface of the dial 117 is knurled, embossed, coated with a high friction material, or the like. When the surgeon rotates the dial 117, a winding shaft (not shown) provided inside the operation body 111 rotates, and the traction wire 80 can be wound up.

[0063] The anti-kink protector 113 covers the base end side of the base end shaft 70 and partially protrudes toward the tip side from the operation main body portion 111. The anti-kink protector 113 suppresses kinking of the base end side of the base end shaft 70.

[0064] Next, a method for manufacturing the sheath 33 constituting the catheter 10 will be described. Here, a manufacturing process for the first sheath 34 will be described. First, a first tube 301 having a certain thickness and a second tube 302 having a thickness greater than that of the first tube 301 are formed, and the first tube 301 and the second tube 302 are arranged adjacent to each other and fused to each other to prepare an unprocessed tube 300, as shown in Fig. 7(a).

[0065] The first tube 301 includes a first tube reinforcement 312 having a repeating structure 313 formed of metal wires 314 inside a first tube body 310 having the same outer and inner diameters over the entire length. The second tube 302 includes a second tube reinforcement 317 having a repeating structure 318 formed of metal wires 319 inside a second tube body 315 having a larger wall thickness than the first tube body 310. The repeating structure 313 of the first tube reinforcement 312 and the repeating structure 318 of the second tube reinforcement 317 are formed at the same pitch.

[0066] The first tube body 310 has an inner layer 310b on the inner surface of the outer layer 310a, and the first tube reinforcement body 312 is disposed between the outer layer 310a and the inner layer 310b. The second tube body 315 has an inner layer 315b on the inner surface of the outer layer 315a, and the second tube reinforcement body 317 is disposed between the outer layer 315a and the inner layer 315b. The inner diameter of the first tube body 310 and the inner diameter of the second tube body 315 are the same, and when the first tube 301 and the second tube 302 are disposed adjacent to each other, the inner layer 310b of the first tube body 310 and the inner layer 315b of the second tube body 315 are adjacent to each other along the longitudinal direction. The first tube reinforcement body 312 and the second tube reinforcement body 317 are also adjacent to each other along the longitudinal direction. The second tube 302 has a larger outer diameter than the first tube 301 and an outer surface thereof is located radially outward from the outer surface of the first tube 301 .

[0067] 7(b), a core material 330 is inserted into the unprocessed tube 300. The core material 330 has an outer diameter that is approximately the same as the inner diameter of the second region 152 of the first sheath 34 to be manufactured. The outer diameter of the core material 330 is 1.3 mm to 1.5 mm.

[0068] Next, the raw tube 300 is inserted into a heated mold 320 from the side of the second tube 302. As shown in FIG. 7(c), the mold 320 has a second region forming portion 321 having an inner diameter smaller than the outer diameter of the second tube 302, a first region forming portion 322 having an inner diameter substantially the same as the outer diameter of the first tube 301, and an intermediate portion 323 inclined so that the diameter becomes smaller from the first region forming portion 322 toward the second region forming portion 321. The inner diameter of the second region forming portion 321 of the mold 320 is 1.6 mm to 1.8 mm. The mold 320 can be heated, and the raw tube 300 can be heated to a high temperature by the heat from the mold 320 to perform a diameter reduction process.

[0069] When the second tube 302, which is one side of the unprocessed tube 300, is inserted into the mold 320 along the longitudinal direction and pulled toward the base end, the first region forming portion 322 reduces the outer diameter of the second tube 302 to the same as the outer diameter of the first tube 301, and the intermediate portion 323 and the second region forming portion 321 further reduce the inner and outer diameters of the second tube 302 while the second tube reinforcement body 317 is stretched in the longitudinal direction and the pitch of the repeating structure 318 becomes larger.

[0070] 7(d), by inserting the unprocessed tube 300 into the mold 320 until the position where the first tube 301 and the second tube 302 are adjacent in the long axis direction is the position of the intermediate portion 323 of the mold 320, the first region forming portion 322 of the mold 320 reaches the base end portion of the first tube 301, and it is possible to form the portion that will become the first region 151, the portion that will become the second region 152, and the portion that will become the first tapered portion 153 in the unprocessed tube 300. Also, the first tube 301 and the second tube 302 can be fused together by heating to form an integrated tube.

[0071] Since the second tube 302 before the diameter reduction process has a larger wall thickness than the first tube 301, the portion that becomes the second region 152 of the second tube 302 that is reduced in diameter by the mold 320 and stretched in the longitudinal direction has the same wall thickness as the first tube 301. In addition, the portion that becomes the first tapered portion 153 of the second tube 302 also has the same wall thickness as the first tube 301. Therefore, the first sheath 34 formed by the diameter reduction process from the unprocessed tube 300 becomes a tube with a constant wall thickness from the tip to the base end. The wall thickness of the first sheath 34 and the wall thickness of the first tube 301 after processing are 0.1 mm to 0.4 mm.

[0072] Here, the manufacturing process of the first sheath 34 has been described, but the second sheath 35 can be manufactured in the same manner. The core material used in manufacturing the second sheath 35 has an outer diameter of 1.2 mm to 1.4 mm. The mold used in manufacturing the second sheath 35 has a third region forming part having an inner diameter substantially equal to the outer diameter of the third region 161 and a fourth region forming part having an inner diameter substantially equal to the outer diameter of the fourth region 162, and the inner diameter of the fourth region forming part is 1.2 mm to 1.4 mm. The first sheath 34 and the second sheath 35 can be connected by covering them with a connection tube 60. In addition, the fourth region 162 of the second sheath 35 can be covered with a wire fixing tube 65 to fix the pulling wire 80.

[0073] Next, a modified catheter 500 will be described. As shown in Fig. 8, the catheter 500 has a stent 510, an outer tube 520 that houses the stent 510, and an inner tube 530 that is placed inside the outer tube 520, and the basic structure is similar to that of the catheter 10 described above. Descriptions of parts having the same structure as the catheter 10 will be omitted.

[0074] The outer tube 520 has a sheath 523. The sheath 523 has a first region 550 on the distal end side, a second region 551 having a smaller diameter than the first region 550 on the proximal end side of the first region 550, and a fifth region 553 having a smaller diameter than the second region 551 on the proximal end side of the second region 551. The sheath 523 has a first tapered portion 553 between the first region 550 and the second region 551, and a second tapered portion 554 between the second region 551 and the fifth region 553. The pulling wire 540 is fixed to the fifth region 552 which is the proximal end of the sheath 523.

[0075] 9, sheath 523 includes reinforcing body 561 having repeating structure 563 in which metal wires 562 are braided around resin tube 560 over the entire length from the tip to the base end. The pitch of repeating structure 563 in reinforcing body 561 is larger in first taper section 553 than in first region 550, larger in second region 551 than in first taper section 553, larger in second region 554 than in second region 551, and larger in fifth region 553 than in second taper section 554. In other words, the pitch of repeating structure 563 increases as the diameter of tube 560 decreases.

[0076] A manufacturing method of the sheath 523 will be described. A first tube 571 having a certain thickness and a second tube 572 having a thickness greater than that of the first tube 571 are formed, and an unprocessed tube 570 is prepared in which the first tube 571 and the second tube 572 are arranged adjacent to each other, as shown in Fig. 10(a). A first tube reinforcing body 580 included in the first tube 571 has the same pitch as a second tube reinforcing body 581 included in the second tube 572.

[0077] As shown in FIG. 10(b), the second tube 572 side of the raw tube 570 into which the core material 330 has been inserted is inserted into a heated mold 320, and the first tube 571 and the second tube 572 are fused and integrated while the second tube 572 is being subjected to a diameter reduction process. This allows the raw tube 570 to be formed with a portion that will become the first region 550, a portion that will become the second region 551, and a portion that will become the first tapered portion 552. Since the second tube 572 is thicker than the first tube 571, it is stretched in the longitudinal direction while being reduced in diameter by the mold 320, and is formed to the same thickness as the first tube 571. Therefore, the first region 550, the second region 551, and the first tapered portion 552 are all formed to the same thickness.

[0078] 10(c), a third tube 573 having a greater thickness than the reduced-diameter second tube 572 is disposed adjacent to the reduced-diameter second tube 572. The second tube 572 and the third tube 573 are disposed adjacent to each other. The third tube 573 includes a third tube reinforcement 582 having the same pitch as the second tube reinforcement 581 included in the second tube 581, the pitch of which has increased due to the reduction in diameter.

[0079] As shown in FIG. 10(d), the third tube 573 side of the raw tube 570 into which the second core material 335 is inserted is inserted into the heated second mold 325, and the second tube 572 and the third tube 573 are fused and integrated while the third tube 573 is being subjected to diameter reduction processing. This allows the raw tube 570 to be formed into a portion that becomes the fifth region 553 and a portion that becomes the second tapered portion 554. Since the third tube 573 is thicker than the second tube 572 that has been subjected to diameter reduction processing, it is stretched in the long axis direction while being reduced in diameter by the second mold 325, and is formed to have the same thickness as the second tube 572. Therefore, the second region 551, the fifth region 553, and the second tapered portion 554 are all formed to have the same thickness. Therefore, the sheath 523 has the same thickness from the first region 550 to the fifth region 553, and becomes a tube with a constant thickness from the tip to the base end.

[0080] Next, a modified example of the first sheath will be described. As shown in FIG. 11(a), the second tube 602 prepared when forming the first sheath 600 may be formed of a resin having a harderness than the first tube 601 disposed adjacent thereto. For example, the flexible first tube 601 can be formed of nylon or fluororesin, and the second tube 602 having a harderness than the first tube 601 can be formed of polyester. As shown in FIG. 11(b), in the formed first sheath 600, the second region 611 corresponding to the portion of the second tube 602 and the first tapered portion 612 have a harderness than the first region 610 corresponding to the portion of the first tube 601. That is, the hardness of the first sheath 600 can be increased on the proximal end side.

[0081] As described above, the method for manufacturing the catheter 10 (1) according to the present embodiment is a method for manufacturing the catheter 10 having a tubular body formed of resin and having a distal end and a proximal end, and includes the steps of preparing an unprocessed tube 300 in which a first tube 301 having a certain thickness and a second tube 302 having a thickness greater than that of the first tube 301 are adjacently arranged along the longitudinal direction, and performing a diameter reduction process on the second tube 302 of the unprocessed tube 300 to make the outer diameter of the processed second tube 302 smaller than the outer diameter of the first tube 301 and to make the wall thickness of the processed second tube 302 the same as that of the first tube 301, thereby forming a tubular body. The method for manufacturing the catheter 10 configured in this manner can make the wall thickness of the second tube 302 the same as that of the first tube 301 after performing a diameter reduction process on the second tube 302 so as to stretch it in the longitudinal direction, thereby preventing the wall thickness from changing in regions of different diameters of the tubular body and preventing local changes in physical properties.

[0082] (2) In the manufacturing method of catheter 10 described above in (1), unprocessed tube 300 may include reinforcing body 157 having repeating structure 159 formed of metal wires 158 over the entire length from the tip to the base end. This enables the manufacturing method of catheter 10 to increase the tensile strength of the formed tubular body.

[0083] (3) In the manufacturing method of catheter 10 described above in (1) or (2), second tube 302 of unprocessed tube 300 may be formed of a resin having a harder resin than first tube 301. In this way, the manufacturing method of catheter 10 can increase the hardness and tensile strength of the formed tubular body toward the base end.

[0084] (4) In any of the above methods for manufacturing catheter 10 (1) to (3), second tube 302 of unprocessed tube 300 may have an outer diameter larger than first tube 301. This allows the method for manufacturing catheter 10 to make the inner diameters of first tube 301 and second tube 302 the same, and makes it possible to easily insert a core material into unprocessed tube 300 for diameter reduction processing in a mold.

[0085] The catheter 10 according to the present embodiment (5) is a catheter 10 including a resin tubular body having a distal end and a proximal end, the tubular body including a first region 151 and a second region 152 at the proximal end of the first region 151, the outer diameter of the second region 152 being smaller than the outer diameter of the first region 151, at least a part of the second region 152 including a tapered section 153 whose outer diameter decreases from the distal end to the proximal end, the resin forming the second region 152 having a greater hardness than the resin forming the first region 151, and the tapered section 153 having a greater hardness than the resin forming the first region 151. The catheter 10 thus configured has a higher hardness on the proximal end side of the tubular body, and therefore can increase the tensile strength when the tubular body is pulled toward the proximal end.

[0086] (6) In the catheter 10 described above in (5), the inner diameter of the second region 152 may be smaller than the inner diameter of the first region 151. This reduces the change in thickness between the first region 151 and the second region 152, thereby reducing the change in physical properties along the longitudinal axis.

[0087] (7) In the catheter 10 of (5) or (6) above, the first region 151 and at least a part of the second region 152 may have the same thickness. This makes it possible to prevent local changes in physical properties and suppress breakage, since the thickness is constant across the first region 151 and the second region 152, which have different outer diameters of the tubular body.

[0088] (8) In any of the catheters 10 described above in (5) to (7), the tubular body may have multiple layers in the thickness direction, and the inner layer of the tubular body may have a resin different from that of the outer layer of the tubular body. This makes it possible to achieve both flexibility of the tubular body and reduced friction of a device inserted therethrough.

[0089] (9) In the catheter 10 of any of (5) to (8) above, the tubular body may have a reinforcing member 157 extending from the first region 151 to the second region 152. This can increase the strength of the tubular body.

[0090] (10) In the catheter 10 of any of (5) to (9) above, the tubular body may have a pulling wire 80 fixed to a proximal end thereof, and the tubular body may be movable toward the proximal end by being pulled by the pulling wire 80. This allows the tubular body to be used as a sheath that covers the stent 20.

[0091] (11) The catheter 10 of (10) above may have an inner tube 40 housed inside the tubular body, a stent 20 disposed on the outer surface of the distal end of the inner tube 40, a proximal outer tube 32 housing the movable tubular body, and an operation unit 110 disposed on the proximal side of the proximal outer tube 32 and fixed to the pulling wire 80. This allows the catheter 10 to be used as a stent placement system.

[0092] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. In the above-described embodiment, a catheter for placing a stent has been described, but the present invention can be applied to other types of catheters as long as they have a tube whose diameter changes at a midpoint in the longitudinal direction. [Explanation of symbols]

[0093] 10 Catheter 20 Stents 30 outer tube 33 Sheath 34 First Sheath 35 Second Sheath 40 Inner tube 70 Base end shaft 80 Towing Wire 110 Operation section 150 First sheath tube body 151 First area 152 Second area 153 First taper section 157 First sheath reinforcement body 160 Second sheath tube body 161 Third area 162 4th area 163 Second taper section 167 Second sheath reinforcement body 300 Raw Tubes 301 1st tube 302 2nd Tube 310 First tube body 312 First tube reinforcement 315 Second Tube Body 317 Second tube reinforcement 320 Mold 321 Second area forming part 322 First area forming part 323 Middle Section 330 Core material 331 Large diameter section 332 Small diameter section 333 Tapered section

Claims

1. A method for manufacturing a catheter having a tubular body made of resin and having a tip and a base end, comprising the steps of: A step of preparing a blank tube in which a first tube having a constant wall thickness and a second tube having a wall thickness greater than that of the first tube are adjacently arranged along a longitudinal direction; a step of forming the tubular body by performing a diameter reduction process on the second tube of the unprocessed tube so that the outer diameter of the processed second tube is smaller than the outer diameter of the first tube and the wall thickness of the processed second tube is the same as the wall thickness of the first tube; A method for manufacturing a catheter comprising the steps of:

2. The method for manufacturing a catheter according to claim 1 , wherein the unprocessed tube includes a reinforcing member having a repeating structure formed of metal wires over the entire length from the distal end to the proximal end.

3. The method for manufacturing a catheter according to claim 1 or 2, wherein the second tube of the unprocessed tube is made of a resin having a higher hardness than the first tube.

4. The method for manufacturing a catheter according to claim 1 or 2, wherein the second tube of the unprocessed tube has an outer diameter larger than that of the first tube.

5. A catheter having a resin tubular body having a distal end and a proximal end, The tube includes a first region and a second region at a proximal end of the first region, The outer diameter of the second region is smaller than the outer diameter of the first region, At least a portion of the second region has a tapered portion in which the outer diameter decreases from the tip end to the base end, the resin forming the second region has a higher hardness than the resin forming the first region; A catheter in which the tapered portion has a hardness greater than that of the resin forming the first region.

6. The catheter of claim 5 , wherein an inner diameter of the second region is smaller than an inner diameter of the first region.

7. The catheter according to claim 5 or 6, wherein the first region and at least a part of the second region have the same wall thickness.

8. 7. The catheter according to claim 5, wherein the tubular body has a plurality of layers in a thickness direction, and an inner layer of the tubular body has a resin different from an outer layer of the tubular body.

9. The catheter according to claim 5 or 6, wherein the tubular body has a reinforcement extending from the first region to the second region.

10. The tube has a traction wire fixed to a proximal end thereof, The catheter according to claim 5 or 6, wherein the tubular body is movable toward the base end by being pulled by the pulling wire.

11. an inner tube accommodated inside the tube body; a stent disposed on an outer surface of the distal end of the inner tube; a proximal outer tube that houses the movable tube body; The catheter according to claim 10, further comprising an operation section disposed on a proximal end side of the proximal outer tube and fixed to the puller wire.

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