catheter

Abstract

Provided is a catheter that can offer greater flexibility while also maintaining kink resistance. This catheter 10 has a tube including a braided reinforcement member 40. The reinforcement member 40 includes: a first spiral section 50 formed by winding first wire materials 51, 51 at prescribed intervals in a first spiral direction; and a second spiral section 60 formed by winding a second wire material 61 in a second spiral direction different from the first spiral direction. The second spiral section 60 has parallel contact portions 65 in which two second wire materials 61 and 61 are arranged in parallel so as to contact each other. Parallel contact portions 65, 65 are formed by being wound at prescribed intervals.

Description

Technical Field

[0001] The present invention relates to a catheter used for injecting an anticancer agent or the like or placing a stent or the like in tubular organs of the human body such as blood vessels, bile ducts, pancreatic ducts, ureters, tracheas, and the like.

Background Art

[0002] Conventionally, a catheter has been inserted into tubular organs such as blood vessels, ureters, bile ducts, tracheas, and the like, and human tissues such as body cavities, and a contrast agent, an anticancer agent, a nutrient agent, or the like has been injected through this catheter, or a guide wire or the like has been used in combination to place a stent, a vascular occluder, or the like.

[0003] This type of catheter has a tubular shape made of a predetermined synthetic resin material, but may have a reinforcing member in order to improve rigidity, kink resistance, and the like.

[0004] For example, Patent Document 1 below describes a catheter having a shaft in which a lumen communicating from the tip to the base end is formed. A reinforcing layer composed of a braid in which fine wires are woven together is provided on the shaft of this catheter from the base end portion to the tip end portion, and the braid is composed of a first spiral portion composed of one or more wire rods wound in a first spiral direction and a second spiral portion composed of one or more wire rods wound in a second spiral direction different from the first spiral direction. It is configured by being arranged so as to cross each other.

[0005] Further, the wire rods constituting the first spiral portion and the wire rods constituting the second spiral portion are arranged with a predetermined gap therebetween, and the gap between the wire rods constituting the first spiral portion is wider than the gap between the wire rods constituting the second spiral portion (see FIG. 4 of Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] In the case of the catheter described in Patent Document 1 above, the first and second helical portions are formed by winding the wire with gaps between them over the entire axial area (from the proximal end to the tip), which may result in poor flexibility.

[0008] In other words, because the wires that make up both helical sections have gaps between them, there are many points where the wires intersect in both helical sections, and the area enclosed by the intersections tends to be narrow. As a result, while the overall kink resistance of the catheter is relatively high, its flexibility tends to be inferior.

[0009] Therefore, the object of the present invention is to provide a catheter that can increase flexibility while maintaining kink resistance. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides a catheter having a tube including a braided reinforcing member, wherein the reinforcing member has a first helical portion formed by winding first wires in a first helical direction with a predetermined gap between them, and a second helical portion formed by winding second wires in a second helical direction different from the first helical direction, wherein the second helical portion has parallel contact portions arranged in parallel so as to be in contact with at least two of the second wires, and these parallel contact portions are formed by winding them with a predetermined gap between them. [Effects of the Invention]

[0011] According to the present invention, the second helical portion has parallel contact portions arranged in parallel so as to be in contact with at least two second wires, and these parallel contact portions are formed by winding with a predetermined gap between them, so that kink resistance can be maintained in the parallel contact portions while flexibility can be increased by the gap between the parallel contact portions. [Brief explanation of the drawing]

[0012] [Figure 1] This is an enlarged cross-sectional view of the main part of one embodiment of the catheter according to the present invention. [Figure 2] This is a cross-sectional view taken along the line of sight of arrow AA in Figure 1. [Figure 3] This is an enlarged diagram illustrating the main part of the catheter according to the present invention. [Figure 4] This is an explanatory diagram comparing a parallel contact section consisting of two thin wires with a single thick wire in the same catheter. [Figure 5] This is a schematic diagram illustrating the flexibility tests of the examples and comparative examples. [Figure 6] This figure shows the results of the flexibility test. [Figure 7] This is a diagram showing the test results of the kink resistance test for the examples and comparative examples. [Modes for carrying out the invention]

[0013] (An embodiment of a catheter) Hereinafter, an embodiment of the catheter according to the present invention will be described with reference to the drawings.

[0014] As shown in Figure 1, the catheter 10 of this embodiment has a tube that includes a reinforcing member 40 made of braid. The tube has a lumen inside.

[0015] In this embodiment, the tube constituting the catheter 10 has an inner layer 20 and an outer layer 30 positioned outside the inner layer 20.

[0016] Note that, in each member such as the catheter 10, the tube, the inner layer 20, the outer layer 30, the reinforcing member 40, the first spiral portion 50, the second spiral portion 60, etc., the "tip portion", "tip", "tip side" mean the distal end portion, distal end, distal end side that is farthest from the hand side of the catheter operator. Further, the "base end portion", "base end", "base end side" mean the proximal end portion, proximal end, proximal end side that is closest to the hand side of the catheter operator. Also, as shown in FIG. 1, the axis of the catheter 10 is taken as the "axis C", and the direction along this axis C is taken as the axial direction (the axial direction in each member has the same meaning).

[0017] As shown in FIG. 1, the inner layer 20 in this embodiment includes a base portion 21 that extends with a constant diameter and a predetermined length, a tapered portion 23 that extends from the tip of the base portion 21 while gradually reducing its diameter toward the foremost tip of the inner layer 20, and a tip portion 25 that extends from the tip of the tapered portion 23 with a constant diameter smaller than the outer diameter of the base portion 21 and a predetermined length.

[0018] This inner layer 20 can adopt, for example, fluororesins such as polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), ethylene tetrafluoride - hexafluoropropylene copolymer (FEP), ethylene tetrafluoride - ethylene copolymer (ETFE), etc., as well as polyurethanes, nylon elastomers, polyether block amides, polyethylene, polyvinyl chloride, vinyl acetate, and resins used in ultraviolet curable resins, adhesives (acrylate resins, urethane - based, epoxy - based, silicone - based). Note that the inner layer 20 in this embodiment is formed from polytetrafluoroethylene (PTFE).

[0019] On the other hand, the outer layer 30 is such that the first layer 31, the second layer 32, the third layer 33, the fourth layer 34, and the fifth layer 35 are continuously provided in the axial direction from the base end side to the tip side of the tube.

[0020] Specifically, the first layer 31 is disposed within a predetermined range of the base portion 21 of the inner layer 20. The second layer 32 is disposed on the tip side of the base portion 21 of the inner layer 20 relative to the location where the first layer 31 is disposed. Further, the third layer 33 is disposed within a range from the tip side of the base portion 21 of the inner layer 20 relative to the location where the second layer 32 is disposed to the base end side of the tip portion 25 via the tapered portion 23.

[0021] The fourth layer 34 is disposed within a predetermined range from the tip side of the tip portion 25 of the inner layer 20 relative to the location where the third layer 33 is disposed. Further, the fifth layer 35 is disposed on the tip side of the tip portion 25 of the inner layer 20 relative to the location where the fourth layer 34 is disposed.

[0022] Furthermore, each of the layers 31 - 35 constituting the outer layer 30 can employ, for example, polyurethane, polyester, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, ultraviolet curable resin, resin used for adhesives (acrylate resin, urethane-based, epoxy-based, silicone-based), fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), ethylene tetrafluoride - hexafluoropropylene copolymer (FEP), ethylene tetrafluoride - ethylene copolymer (ETFE), etc.

[0023] Also, from the perspective of ensuring operability and torque transmission, the hardness of each of the layers 31 - 35 is set such that the first layer 31 is the hardest and gradually decreases toward the fifth layer 35.

[0024] Furthermore, as shown in FIG. 1, an X-ray impermeable marker 37 formed from an X-ray impermeable metal made of, for example, W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, Ir, and alloys thereof is embedded in the fifth layer 35 disposed on the tip portion side of the outer layer 30.

[0025] Also, the outer periphery of the outer layer 30 is coated with a hydrophilic resin film 39 made of, for example, polyvinyl pyrrolidone, polyethylene glycol, methyl vinyl ether maleic anhydride copolymer, etc.

[0026] Next, we will describe the reinforcing member 40 in detail.

[0027] As shown in Figure 3, the reinforcing member 40 has a first helical portion 50 formed by winding first wires 51 together in a first helical direction with a predetermined gap between them, and a second helical portion 60 formed by winding second wires 61 in a second helical direction different from the first helical direction (the second helical portion 60 is formed by winding second wires 61 in a second helical direction different from the first helical direction, and is arranged so that the second wires 61 intersect with the first wires 51 of the first helical portion 50). In this embodiment, both the first wires 51 and the second wires 61 are round wires with a circular cross-section.

[0028] Figure 2 is a cross-sectional view taken along the line of arrow AA in Figure 1, that is, a cross-sectional view taken by cutting the catheter 10 at a predetermined position on the tip side and viewing it from the proximal end to the tip side. Figure 3 shows the catheter 10 with the outer layer 30 removed for convenience. Furthermore, in Figure 3, the right side of the drawing is the proximal end of the catheter 10, and the left side of the drawing is the tip side of the catheter 10.

[0029] Furthermore, the first helical direction R1 (hereinafter also simply referred to as "first helical direction R1") is determined by the inclination angle θ1 of the first wire 51 with respect to the axis C of the catheter 10 and the winding direction of the first wire 51, while the second helical direction R2 (hereinafter also simply referred to as "second helical direction R2") is determined by the inclination angle θ2 of the second wire 61 with respect to the axis C of the catheter 10 and the winding direction of the second wire 61.

[0030] In other words, as shown in Figure 3, the first helical portion 50 is formed by winding the first wire 51 spirally in a clockwise direction when viewed from the proximal end to the tip of the catheter 10, while tilting it at a predetermined angle θ1 with respect to the axis C of the catheter 10, as shown in Figure 2.

[0031] Furthermore, the first wires 51, 51 are arranged with a predetermined gap S1 (see Figure 3) in the axial direction of the first helical section 50. This gap S1 is wider at the base end than at the tip end of the first helical section 50. Note that, for the sake of explanation, Figure 3 shows the middle section of the first helical section 50. In this middle section, the gap S1 between the first wires 51, 51 is almost constant, but the gap S1 on the base end side (right side in Figure 3) of the middle section shown in Figure 3 is wider than the gap S1 on the tip side (left side in Figure 3) of the middle section shown in Figure 3.

[0032] The gap S1 is the length between the tangent to one side edge in the width direction of a predetermined first wire 51 (the right side edge in Figure 3) and the tangent to the other side edge in the width direction of another first wire 51 (the left side edge in Figure 3), which is positioned adjacent to the predetermined first wire 51 in the axial direction of the first spiral portion 50.

[0033] Furthermore, the gap S1 between the first wires 51, 51 of the first helical portion 50 is preferably 0.03 to 0.25 mm, and more preferably 0.06 to 0.20 mm.

[0034] Furthermore, the first helical portion 50 in this embodiment consists of eight first wires 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h, which are wound around the first helical portion 50 in the axial direction while maintaining a predetermined gap S1.

[0035] Here, the first wires 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h are arranged in order from the tip to the base of the first helical section 50. After the first wire 51h, the first wire 51a is placed again.

[0036] Furthermore, the angle θ1 of the first wire 51 forming the first helical portion 50 with respect to the axis C of the catheter 10 is preferably 100 to 140°, and more preferably 110 to 130°.

[0037] On the other hand, as shown in Figure 3, the second helical portion 60 is formed by winding the second wire 61 spirally in a direction different from the first helical direction R1, in this case counterclockwise (leftward rotation), when viewing the reinforcing member 40 from the proximal end to the tip of the catheter 10, as shown in Figure 2, while tilting the second wire 61 at a predetermined angle θ2 with respect to the axis C of the catheter 10.

[0038] The second spiral portion 60 has parallel contact portions 65 arranged in parallel so as to contact at least two second wires 61, and these parallel contact portions 65, 65 are formed by winding them with a predetermined gap between them.

[0039] In this embodiment, as shown in Figure 3, the two second wires 61, 61 are arranged in parallel so that they are in contact with each other (the second wires 61, 61 are arranged in parallel so that they are in contact with each other without any gaps), thereby forming the parallel contact portion 65.

[0040] More specifically, one side edge in the width direction of one second wire 61 (the right side edge of the second wire 61 located on the left of the two second wires 61, 61 constituting the parallel contact portion 65 in Figure 3) and the other side edge in the width direction of the other second wire 61, which is positioned adjacent to this second wire 61 in the axial direction of the second spiral portion 60 (the left side edge of the second wire 61 located on the right of the two second wires 61, 61 constituting the parallel contact portion 65 in Figure 3), contact each other, thereby forming a parallel contact portion 65 which is a single unit of two wires.

[0041] Furthermore, the two parallel contact portions 65, 65 are arranged in the axial direction C of the second helical portion 60 with a predetermined gap S2 (see Figure 3) between them. This gap S2 is wider at the base end than at the tip end of the second helical portion 60. Note that for the sake of explanation, Figure 3 shows the middle portion of the second helical portion 60, and in this middle portion, the gap S2 between the second wires 61, 61 is almost constant, but the gap S2 on the base end side (right side in Figure 3) of the middle portion shown in Figure 3 is wider than the gap S2 on the tip side (left side in Figure 3) of the middle portion shown in Figure 3.

[0042] The gap S2 is the length between the tangent to one side edge in the width direction of the predetermined parallel contact portion 65 (the side edge of the right-hand second wire 61 that constitutes the predetermined parallel contact portion 65 in Figure 3) and the tangent to the other side edge in the width direction of another parallel contact portion 65 that is positioned adjacent to the predetermined parallel contact portion 65 in the axial direction of the second spiral portion 60 (the side edge of the left-hand second wire 61 that constitutes the other parallel contact portion 65 in Figure 3).

[0043] Furthermore, the gap S2 between the parallel contact portions 65, 65 of the second helical portion 60 is preferably 0.06 to 0.50 mm, and more preferably 0.12 to 0.40 mm.

[0044] Furthermore, the second helical portion 60 in this embodiment consists of eight second wires 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h, where the second wires 61a and 61b are in contact with each other, the second wires 61c and 61d are in contact with each other, the second wires 61e and 61f are in contact with each other, and the second wires 61g and 61h are in contact with each other, forming a pair of parallel contact portions 65, which are wound around the second helical portion 60 while maintaining a predetermined gap S2 in the axial direction.

[0045] Here, the second wires 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h are arranged in order from the tip to the base of the second helical portion 60, and this combination constitutes one parallel contact portion 65. Following the parallel contact portion 65 consisting of the second wires 61g and 61h, another parallel contact portion 65 consisting of the second wires 61a and 61b is arranged.

[0046] Furthermore, as shown in Figure 3, in this embodiment, the parallel contact portion 65, consisting of two second wires 61, 61 that are in contact with each other, is located outside (radially outward) of the first wire 51 at two predetermined locations in the direction of travel of the second helical direction R2, located inside (radially inward) of the first wire 51 at the next two locations, located outside the first wire 51 again at the next two locations, and thereafter, it alternates between being inside, outside, inside of the first wire 51, and so on, weaving together while intersecting with the first wire 51 of the first helical portion 50 to form the second helical portion 60.

[0047] Furthermore, in this embodiment, the gap S2 between the parallel contact portions 65, 65 of the second helical portion 60 is set to be wider than the gap S1 between the first wires 51, 51 of the first helical portion 50.

[0048] Furthermore, as shown in Figure 3, the space K1 formed by the intersection of multiple first wires 51 of the first helical section 50 and multiple second wires 61 of the second helical section 60 has a substantially parallelogram shape (the parallel contact portions 65, 65 are arranged on the shorter side, and the first wires 51, 51 are arranged on the longer side, forming the region enclosed by them), and this substantially parallelogram-shaped space K1 is arranged over the entire area from the tip to the base of the reinforcing member 40.

[0049] Furthermore, each space K1 is configured such that the area is smaller on the tip side of the reinforcing member 40 than on the base side. In Figure 3, for the sake of explanation, the middle section of the reinforcing member 40 is shown, and the areas of each space K1 in this middle section are approximately the same. However, the area of ​​each space K1 on the tip side of the section shown in Figure 3 (left side in Figure 3) is smaller than the area of ​​each space K1 on the base side of the middle section shown in Figure 3 (right side in Figure 3).

[0050] Furthermore, in this embodiment, the number of first wires 51 forming the first helical portion 50 and the number of second wires 61 forming the second helical portion 60 are the same.

[0051] As described above, in this embodiment, the first wire 51 forming the first helical portion 50 consists of eight wires: 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h. Similarly, the second wire 61 forming the second helical portion 60 also consists of eight wires: 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h, with the same number of wires.

[0052] Furthermore, as shown in Figure 2, the catheter 10 is arranged such that at least the parallel contact portion 65 is in contact with the outer circumference of the inner layer 20, and the outer layer 30 is configured not to be inserted between the outer circumference of the inner layer 20 and the second wires 61, 61 that constitute the parallel contact portion 65 positioned in contact with the outer circumference.

[0053] In this embodiment, a parallel contact portion 65 consisting of two second wires 61, 61 is arranged to contact the outer circumference of the inner layer 20. As a result, a predetermined gap K2 is defined between the outer circumference of the inner layer 20 and the second wires 61, 61 constituting the parallel contact portion 65, and the outer layer 30 does not enter this gap K2. Furthermore, a first wire 51 is arranged in contact with the outside (radially outward) of the two second wires 61, 61.

[0054] Furthermore, as shown in Figure 2, the outer layer 30 extends to the outside of the second wires 61,61 and the first wire 51 that constitute the parallel contact portion 65, and also extends into the space K1 formed by the intersection of the wires 51,61. It can also be said that the second wires 61,61 and the first wire 51 are embedded inside the outer layer 30. As a result, the displacement of the second wires 61,61 and the first wire 51 relative to the inner layer 20 (displacement radially outward and displacement in the circumferential direction) is restricted.

[0055] In this embodiment, as described above, the parallel contact portion 65 has a braided pattern that intersects the first wire 51 so as to be alternately located on the outside and inside of the first wire 51 (see paragraph 0046). Therefore, in the helical trajectory of the second helical portion 60 in the second helical direction R2, the parallel contact portion 65 has portions that contact the outer circumference of the inner layer 20 and portions that do not. In other words, the entire parallel contact portion 65 does not abut the outer circumference of the inner layer 20, but rather portions that abut and portions that do not abut are alternately located along the helical trajectory in the second helical direction R2.

[0056] Furthermore, as shown in Figure 1, the reinforcing member 40 is not positioned all the way to the very tip of the inner layer 20, but rather is positioned in the range from a predetermined position on the inner layer 20 to just before the very tip. In other words, the reinforcing member 40 is not positioned at the very tip of the outer layer 30. As a result, flexibility is ensured at the very tip of the catheter 10.

[0057] Furthermore, the angle θ2 of the second wire 61 forming the second helical portion 60 with respect to the axis C of the catheter 10 is preferably 100 to 140°, and more preferably 110 to 130°.

[0058] As the first wire 51 of the first helical portion 50 and the second wire 61 of the second helical portion 60 that constitute the reinforcing member 40 described above, for example, stainless steel, piano wire, and superelastic alloys such as Ni-Ti alloys, Ni-Ti-X (X=Fe, Cu, V, Co, Cr, Mn, Nb, etc.) alloys, and Cu-Zn-X (X=Al, Fe, etc.) alloys can be used. Alternatively, X-ray opaque metals made of W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta and their alloys can also be used. In this embodiment, the first wire 51 and the second wire 61 are made of W.

[0059] Furthermore, the wire diameters of the first wire 51 and the second wire 61 are preferably 0.010 to 0.050 mm, and more preferably 0.015 to 0.030 mm. In addition, the outer diameter of the reinforcing member 40 is preferably 0.40 to 5.00 mm, and more preferably 0.50 to 1.00 mm.

[0060] (modified version) The shape, structure, material, and layout of the components of the catheter described above, such as the tube, inner layer, outer layer, reinforcing member, first helical section, and second helical section, are not limited to the above-described embodiments.

[0061] In this embodiment, the inner layer 20 has a tapered portion 23, but the inner layer may also have a shape that extends with a constant diameter from the base to the tip, a shape in which multiple cylindrical portions with different outer diameters are connected in the axial direction while extending with a constant diameter (a shape in which the outer circumference is stepped), or a shape that combines a cylindrical portion extending with a constant diameter and a tapered portion.

[0062] Furthermore, in this embodiment, the outer layer 30 has a shape in which layers 31, 32, 33, 34, and 35 with different hardnesses are arranged in a continuous manner in the axial direction. However, the outer layer may be a single layer made of the same material from the base to the tip.

[0063] Furthermore, in this embodiment, the first helical direction R1 of the first helical portion 50 constituting the reinforcing member 40 is clockwise, and the second helical direction R2 of the second helical portion 60 is counterclockwise. However, for example, the first helical direction R1 of the first helical portion and the second helical direction R2 of the second helical portion may both be clockwise or counterclockwise, and the inclination angle θ1 of the first wire 51 with respect to the axis C of the catheter 10 and the inclination angle θ2 of the second wire 61 with respect to the axis C of the catheter 10 may be set to different angles, as long as the first helical direction R1 and the second helical direction R2 are different.

[0064] Furthermore, in this embodiment, the parallel contact portion 65 is formed by arranging two second wires 61 in parallel so as to be in contact with each other, but there may be three or more second wires 61 that constitute the parallel contact portion.

[0065] Furthermore, in this embodiment, the gap S2 between the parallel contact portions 65, 65 of the second helical portion 60 is set to be wider than the gap S1 between the first wires 51, 51 of the first helical portion 50. However, the gap S2 may be narrower than the gap S1, and both gaps S1 and S2 may be the same.

[0066] Furthermore, although the number of first wires 51 forming the first helical portion 50 and the number of second wires 61 forming the second helical portion 60 are the same, the number of first wires and the number of second wires may be different, and the number of one of the first or second wires may be greater or less than the number of the other.

[0067] Furthermore, in this embodiment, the braiding pattern of the parallel contact portion 65 with respect to the first wire 51 alternately intersects the outside and inside of the first wire 51 at two locations each in the direction of travel in the second helical direction R2 (see Figure 3). However, for example, a braiding pattern that alternately intersects the outside and inside of the first wire at one location each may also be used.

[0068] Furthermore, in this embodiment, the gap S1 between the first wires 51, 51 of the first helical portion 50 is wider at the base end of the first helical portion 50 than at the tip end. However, this gap S1 may be constant throughout the entire axial range from the base end to the tip of the first helical portion 50, or it may be wider at the tip end of the first helical portion 50 than at the base end, or it may gradually widen from the base end to the tip of the first helical portion 50, or it may gradually narrow.

[0069] Furthermore, in this embodiment, the gap S2 between the parallel contact portions 65, 65 of the second helical portion 60 is wider at the base end of the second helical portion 60 than at the tip end. However, this gap S2 may be constant throughout the entire axial range from the base end to the tip of the second helical portion 60, wider at the tip end than at the base end, gradually wider from the base end to the tip of the second helical portion 60, or gradually narrower.

[0070] (Effects and Benefits) Next, we will describe an example of how to use the catheter according to the present invention, which has the above structure, and its effects and other aspects.

[0071] This catheter 10 is used, for example, to inject contrast agents, anticancer drugs, etc., or to place stents, etc., at predetermined locations in human body tissues such as blood vessels such as hepatic arteries, bile ducts, pancreatic ducts, ureters, tracheas, etc. However, the catheter 10 may be used at locations other than those mentioned above, and the location of use is not particularly limited.

[0072] First, after administering a contrast agent into the body, the catheter 10 is guided and moved using a guidewire (not shown) under X-ray fluoroscopy (radiofluoroscopy) by a well-known method such as the Seldinger technique.

[0073] In this case, it may be necessary to select and advance a specific small-diameter tubular organ from among several small-diameter tubular organs branching off from a large-diameter tubular organ; for this purpose, the catheter 10 requires flexibility. Furthermore, in order to ensure that drug solutions such as anticancer drugs reach the affected area, the catheter 10 must not kink and must maintain its lumen; in other words, it must be kink-resistant.

[0074] In contrast, in the catheter 10 of the present invention, as described above, the second helical portion 60 has parallel contact portions 65 arranged in parallel so as to bring at least two second wires 61, 61 into contact with each other, and these parallel contact portions 65, 65 are formed by winding them with a predetermined gap between them.

[0075] Therefore, in the parallel contact portion 65, the flexibility of the catheter 10 can be increased by the gap between the parallel contact portions 65, 65 while maintaining the kink resistance of the catheter 10.

[0076] Therefore, the above requirements (maintaining kink resistance and improving flexibility) can be satisfied. Thus, it can be suitably used, for example, when inserting a catheter 10 into the hepatic artery and injecting anticancer drugs into the liver through the hepatic artery during the treatment of liver cancer.

[0077] Incidentally, in order to maintain the kink resistance of the catheter 10, it is conceivable to use a single thick wire for the second wire 61 that forms the second helical portion 60. However, in this case, although the kink resistance of the catheter 10 can be maintained, the flexibility of the catheter 10 is likely to decrease.

[0078] In contrast, the catheter 10 of the present invention has a parallel contact portion 65 formed by arranging at least two second wires 61 that form the second helical portion 60 in parallel so as to be in contact with each other. Therefore, it is possible to obtain kink resistance similar to that obtained when using one thick wire, as if multiple wires were bundled together. Furthermore, it is possible to use thinner wires that are more flexible than thicker wires while maintaining kink resistance, and the flexibility of the catheter 10 can be increased by the gap S2 between the parallel contact portions 65, 65.

[0079] Furthermore, compared to a single thick wire, arranging at least two second wires 61, 61 in parallel so that they are in contact with each other helps to suppress the increase in outer diameter. That is, as shown in Figure 4, when comparing the width (horizontal direction in the plane of Figure 4) of the parallel contact portion 65 formed by the contact of two second wires 61, 61 with that of a single thick wire with the same outer diameter, the outer diameter dimension of the two second wires 61, 61 (meaning the dimension in the vertical direction in the plane of Figure 4; see the arrow in Figure 4) can be made smaller than the outer diameter of a single thick wire. As a result, the outer diameter of the catheter 10 can be reduced.

[0080] Furthermore, in this embodiment, the gap S2 between the parallel contact portions 65, 65 of the second helical portion 60 is set to be wider than the gap S1 between the first wires 51, 51 of the first helical portion 50.

[0081] According to the above embodiment, since the gap S2 is set as described above, a wide space K1 can be secured where the second wire 61 of the second helical section 60 intersects with the first wire 51 of the first helical section 50, thereby increasing the flexibility of the catheter 10. In addition, the number of second wires 61 of the second helical section 60 in a predetermined region can be brought closer to the number of first wires 51 of the first helical section 50, and from this viewpoint as well, the flexibility of the catheter 10 can be increased.

[0082] Furthermore, in this embodiment, the number of first wires 51 forming the first helical portion 50 and the number of second wires 61 forming the second helical portion 60 are the same.

[0083] According to the above embodiment, the number of first wires 51 forming the first helical portion 50 and the number of second wires 61 forming the second helical portion 60 are the same, making it easier to widen the gap between the parallel contact portions 65, 65 in the second helical portion 60, and further increasing the flexibility of the catheter 10.

[0084] In this embodiment, the tube has an inner layer 20 and an outer layer 30 positioned outside the inner layer 20. The outer layer 30 is positioned so that at least a parallel contact portion 65 is in contact with the outer circumference of the inner layer 20, and the outer layer 30 is configured not to penetrate between the outer circumference of the inner layer 20 and the second wires 61, 61 that constitute the parallel contact portion 65 positioned in contact with the outer circumference (see Figure 2).

[0085] According to the above embodiment, the outer layer 30 is configured not to penetrate between the outer periphery of the inner layer 20 and the second wires 61, 61 that constitute the parallel contact portion 65 arranged in contact with the outer periphery. Therefore, the second wires 61, 61 that constitute the parallel contact portion 65 are not completely restrained from each other and are able to displace to a certain extent. This increases the flexibility of the reinforcing member 40, and consequently increases the flexibility of the catheter 10. [Examples]

[0086] (Examples) Catheters of the embodiment, having the same shape and structure as those shown in Figures 1-3, were manufactured. The first and second helical sections 50 and 60 are formed by winding eight first and second wires 51 and 61, respectively.

[0087] (Comparative example) A comparative catheter was manufactured in which the first and second helical sections were formed by winding eight first and second wires, respectively, the inclination angles θ1 and θ2 of the first and second wires with respect to the catheter axis were the same as in the example, and furthermore, the second helical section was formed by winding the second wires with an axial gap between them without them touching each other.

[0088] (Flexibility confirmation test) As shown in Figure 5, the catheters of the example and comparative example were set in a well-known indentation load measuring test machine 100. Each catheter was fixed so that its leading edge was 4 mm from the end face of the indentation load measuring test machine 100. An indentation load F was then applied at a predetermined speed at a position 1 mm from the tip of each catheter, and it was pushed in 0.5 mm. The rebound load (resistance load) at that time was measured. This test was performed three times for each catheter of the example and comparative example.

[0089] The results are shown in Figure 6. Figure 6 shows that a smaller rebound load corresponds to higher flexibility. As shown in Figure 6, the rebound load of the example is smaller than that of the comparative example, and the flexibility of the example is higher than that of the comparative example.

[0090] (Kink resistance test) The tip of the catheters of the examples and comparative examples was clamped in a U-shape using a predetermined measuring instrument capable of gripping the object. Then, the clamping amount of the measuring instrument was gradually reduced, and the outer diameter was measured each time the clamping amount reached a predetermined value. This test was performed three times for each catheter of the examples and comparative examples.

[0091] The results are shown in Figure 7. The horizontal axis in Figure 7 represents the amount of clamping of each catheter by the measuring instrument. The vertical axis in Figure 7 represents the outer diameter retention rate, which is the ratio of the outer diameter of the catheter at the start of the test (initial state) to the outer diameter at the time of measurement (initial state outer diameter / outer diameter at measurement × 100). A decrease in this outer diameter retention rate indicates that kinking has occurred.

[0092] As shown in Figure 7, the catheter in the example and the catheter in the comparative example show almost the same trend in the decrease in outer diameter retention. Therefore, it can be seen that the catheter in the example has almost the same kink resistance as the catheter in the comparative example.

[0093] It should be noted that the present invention is not limited to the embodiments described above, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of Symbols]

[0094] 10 Catheters 20 Inner layer 30 outer layer 40 Reinforcement members 50 1st spiral part 51 1st wire rod 60 Second spiral part 61 2nd wire rod 65 Parallel contact part

Claims

1. A catheter having a tube that includes a reinforcing member made of braid, The reinforcing member is A first helical portion is formed by winding multiple first wires together in a first helical direction with a predetermined gap between them, It has a second helical portion formed by winding the second wire in a second helical direction different from the first helical direction, The second helical portion has parallel contact portions arranged in parallel so as to contact at least two of the second wires, and these parallel contact portions are constructed by weaving them together so as to intersect with the first wires, so as to be located on the outside and inside of the first wires. The catheter is characterized in that the parallel contact portion consists of at least two sets of sets, each set comprising at least two sets of second wires arranged in parallel so as to be in contact with each other, and each set comprising at least two second wires, different from the second wires constituting the set, arranged in parallel so as to be in contact with each other, and the sets are wound around each other with a predetermined gap between them to form the second spiral portion.

2. The catheter according to claim 1, wherein the gaps between the sets of parallel contact portions of the second helical portion are set to be wider than the gaps between the plurality of first wires of the first helical portion.

3. The catheter according to claim 1 or 2, wherein the number of first wires forming the first helical portion and the number of second wires forming the second helical portion are the same.

4. The tube has an inner layer and an outer layer disposed outside the inner layer. The inner layer is arranged so as to contact at least the parallel contact portion with the outer circumference of the inner layer, The catheter according to claim 1 or 2, configured such that the outer layer does not penetrate between the outer circumference of the inner layer and the second wire constituting the parallel contact portion that is in contact with the outer circumference.

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