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

catheter

[0001] The present invention relates to a catheter used for injecting anti-cancer drugs or placing stents in tubular organs of the human body, such as blood vessels, bile ducts, pancreatic ducts, ureters, and tracheas.

[0002] Conventionally, catheters have been inserted into tubular organs such as blood vessels, ureters, bile ducts, and tracheas, or into human tissues such as body cavities, and contrast agents, anticancer drugs, nutrients, etc., have been injected through the catheter, or stents, vascular occlusion devices, etc. have been placed in combination with guidewires, etc.

[0003] This type of catheter is tubular and made of a specific synthetic resin material, and may have a reinforcing member to improve rigidity, kink resistance, and the like.

[0004] For example, Patent Document 1 below describes a catheter having a shaft with a lumen formed therein that communicates from the distal end to the proximal end. The catheter shaft is provided with a reinforcing layer formed of a braid of interwoven thin wires from the proximal end to the distal end, and the braid is formed by intersecting a first helical portion made of one or more wires wound in a first helical direction and a second helical portion made of one or more wires wound in a second helical direction different from the first helical direction.

[0005] Furthermore, the wire rods constituting the first spiral portion and the wire rods constituting the second spiral portion are arranged with a predetermined gap between them, 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 Figure 4 of Patent Document 1).

[0006] JP 2012-29872 A

[0007] In the case of the catheter described in Patent Document 1, the first spiral portion and the second spiral portion are formed by winding the wire over the entire axial direction (from the base end to the tip end) with gaps between the wires, which could result in poor flexibility.

[0008] In other words, because the wires that make up both spiral sections have gaps between them, there are many points where the wires in both spiral sections intersect, and the area surrounded by the intersections tends to be narrow.As a result, although the catheter as a whole has relatively high kink resistance, it tends to have poor flexibility.

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

[0010] In order to achieve the above-mentioned object, the present invention provides a catheter having a tube including a reinforcing member made of braid, wherein the reinforcing member has a first helical portion formed by winding first wire rods together in a first helical direction with a predetermined gap therebetween, and a second helical portion formed by winding a second wire rod together in a second helical direction different from the first helical direction, and the second helical portion has parallel contact portions arranged in parallel so that at least two of the second wire rods are in contact with each other, and the parallel contact portions are formed by winding the second wire rods together with a predetermined gap therebetween.

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

[0012] 1 is an enlarged cross-sectional view of a main part of an embodiment of a catheter according to the present invention; FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1; FIG. 3 is an enlarged explanatory view of a main part of a catheter according to the present invention; FIG. 4 is an explanatory view comparing a parallel contact portion made of two thin wires with a single thick wire in the same catheter; FIG. 5 is a schematic explanatory view of a flexibility test of Examples and Comparative Examples; FIG. 6 is a diagram showing test results of a flexibility test; and FIG. 7 is a table showing test results of a kink resistance test of Examples and Comparative Examples.

[0013] (One Embodiment of Catheter) Hereinafter, one embodiment of a 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 including a braided reinforcing member 40. The tube has an internal lumen.

[0015] In this embodiment, the tube that constitutes the catheter 10 has an inner layer 20 and an outer layer 30 that is disposed on the outside of the inner layer 20 .

[0016] The terms "tip portion," "tip," and "tip side" of the catheter 10, tube, inner layer 20, outer layer 30, reinforcing member 40, first helical portion 50, second helical portion 60, and other components refer to the distal end, distal end, and distal end side that are farthest from the catheter operator's hand, and the terms "base portion," "base end," and "base end side" refer to the proximal end, proximal end, and proximal end side that are closest to the catheter operator's hand. Also, as shown in Figure 1, the axis of the catheter 10 is referred to as "axis center C," and the direction along this axis center C is referred to as the axial direction (the same applies to the axial direction of each component).

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

[0018] The inner layer 20 may be made of, for example, fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polyurethane, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, ultraviolet curing resin, or resins used in adhesives (acrylate resin, urethane-based, epoxy-based, silicone-based). Note that the inner layer 20 in this embodiment is made of polytetrafluoroethylene (PTFE).

[0019] On the other hand, the outer layer 30 is made up of a first layer 31, a second layer 32, a third layer 33, a fourth layer 34, and a fifth layer 35 that are arranged axially from the base end of the tube toward the tip end.

[0020] Specifically, the first layer 31 is disposed in a predetermined range in the base 21 of the inner layer 20. The second layer 32 is disposed in the base 21 of the inner layer 20, distal to the location of the first layer 31. The third layer 33 is disposed in a range extending from the distal side of the location of the second layer 32 in the base 21 of the inner layer 20, via the tapered portion 23, to the proximal end of the distal portion 25.

[0021] The fourth layer 34 is disposed within a predetermined range of the distal end 25 of the inner layer 20 from the distal end side of the third layer 33. The fifth layer 35 is disposed within the distal end 25 of the inner layer 20 from the distal end side of the fourth layer 34.

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

[0023] The hardness of each layer 31 to 35 is set so that the first layer 31 is the hardest and gradually decreases toward the fifth layer 35 in order to ensure operability and torque transmission.

[0024] Furthermore, as shown in FIG. 1, a fifth layer 35 arranged on the distal end side of the outer layer 30 has embedded therein a radiopaque marker 37 formed from a radiopaque metal such as W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, Ir, or an alloy thereof.

[0025] The outer layer 30 is coated on its outer periphery with a hydrophilic resin film 39 made of, for example, polyvinylpyrrolidone, polyethylene glycol, methyl vinyl ether-maleic anhydride copolymer, or the like.

[0026] Next, the reinforcing member 40 will be described in detail.

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

[0028] Figure 2 is a cross-sectional view taken along the line A-A in Figure 1, i.e., a cross-sectional view of the catheter 10 cut at a predetermined position on the distal end side and viewed from the base end side to the distal end side of the catheter 10. For convenience, Figure 3 shows the catheter 10 without the outer layer 30. Furthermore, in Figure 3, the right side of the drawing is the base end side of the catheter 10, and the left side of the drawing is the distal end side of the catheter 10.

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

[0030] That is, as shown in Figure 3, the first spiral portion 50 is formed by inclining the first wire 51 at a predetermined angle θ1 with respect to the axis C of the catheter 10, and by winding the first wire 51 in a spiral manner in a right-handed (clockwise) direction when viewing the reinforcing member 40 from the base end side toward the tip end side of the catheter 10, as shown in Figure 2.

[0031] The first wires 51, 51 are arranged with a predetermined gap S1 (see FIG. 3 ) between them in the axial direction of the first helical portion 50. This gap S1 is wider at the base end side than at the tip end side of the first helical portion 50. Note that FIG. 3 shows the middle portion of the first helical portion 50 for ease of explanation, and in this middle portion, the gap S1 between the first wires 51, 51 is approximately constant, but the gap S1 on the base end side of the middle portion shown in FIG. 3 (right side in FIG. 3 ) is wider than the gap S1 on the tip end side of the middle portion shown in FIG. 3 (left side in FIG. 3 ).

[0032] The gap S1 is the length between a tangent at one widthwise side edge (the right side edge in Figure 3) of a specified first wire rod 51 and a tangent at the other widthwise side edge (the left side edge in Figure 3) of another first wire rod 51 that is arranged adjacent to the specified first wire rod 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 spiral portion 50 is preferably 0.03 to 0.25 mm, and more preferably 0.06 to 0.20 mm.

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

[0035] Here, the first wire rods 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h are arranged in this order from the distal end to the proximal end of the first helical portion 50. After the first wire rod 51h, the first wire rod 51a is again arranged.

[0036] The angle θ1 of the first wire 51 forming the first spiral 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 spiral portion 60 is formed by inclining the second wire 61 at a predetermined angle θ2 with respect to the axis C of the catheter 10, and by winding the second wire 61 in a spiral shape in a direction different from the first spiral direction R1, in this case, leftward (counterclockwise), which is the opposite direction to the first spiral direction R1, when the reinforcing member 40 is viewed from the base end side to the tip end side of the catheter 10, as shown in Figure 2.

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

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

[0040] More specifically, one side edge in the width direction of one second wire 61 (in Figure 3, the right side edge of the second wire 61 located on the left side of the two second wires 61, 61 that make up the parallel contact portion 65) and the other side edge in the width direction of the other second wire 61 that is located adjacent to this second wire 61 in the axial direction of the second spiral portion 60 (in Figure 3, the left side edge of the second wire 61 located on the right side of the two second wires 61, 61 that make up the parallel contact portion 65) come into contact with each other, thereby forming a set of two parallel contact portions 65.

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

[0042] The gap S2 is the length between a tangent to one widthwise edge of a given parallel contact portion 65 (in Figure 3, the side edge of the second wire rod 61 on the right side that constitutes the given parallel contact portion 65) and a tangent to the other widthwise edge of another parallel contact portion 65 that is arranged adjacent to the given parallel contact portion 65 in the axial direction of the second spiral portion 60 (in Figure 3, the side edge of the second wire rod 61 on the left side that constitutes the other parallel contact portion 65).

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

[0044] Furthermore, in this embodiment, the second spiral portion 60 consists of eight second wire rods 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h, and the second wire rods 61a and 61b are in contact with each other, the second wire rods 61c and 61d are in contact with each other, the second wire rods 61e and 61f are in contact with each other, and the second wire rods 61g and 61h are in contact with each other, so that two of them form a set of parallel contact portions 65, which are formed by being wound around the second spiral portion 60 in the axial direction while maintaining a predetermined gap S2.

[0045] Here, second wire rods 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h are arranged in this order from the distal end to the proximal end of the second spiral portion 60, and the above combination constitutes one parallel contact portion 65. After the parallel contact portion 65 made up of second wire rods 61g and 61h, another parallel contact portion 65 made up of second wire rods 61a and 61b is arranged.

[0046] Also, as shown in Figure 3, in this embodiment, the parallel contact portion 65 consisting of two second wire rods 61, 61 in contact with each other is located outside (radially outside) the first wire rod 51 at two predetermined locations in the traveling direction of the second spiral direction R2, located inside (radially inside) the first wire rod 51 at the next two locations, and located outside the first wire rod 51 again at the next two locations, and thereafter is woven while crossing the first wire rod 51 of the first spiral portion 50 so as to be alternately located outside and inside the first wire rod 51, i.e., inside, outside, inside of the first wire rod 51, thereby forming the second spiral 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] As shown in FIG. 3 , the space K1 formed by the intersection of the multiple first wires 51 of the first spiral portion 50 and the multiple second wires 61 of the second spiral portion 60 has an approximately parallelogram shape (the parallel contact portions 65, 65 are arranged on the short side, and the first wires 51, 51 are arranged on the long side, and the area surrounded by them), and this approximately parallelogram-shaped space K1 is arranged over the entire area from the tip to the base end of the reinforcing member 40.

[0049] Each space K1 is configured to have a smaller area on the distal side than on the proximal side of the reinforcing member 40. For ease of explanation, Fig. 3 shows the middle portion of the reinforcing member 40, and each space K1 in this middle portion has approximately the same area, but the area of ​​each space K1 on the distal side of the portion shown in Fig. 3 (left side in Fig. 3) is smaller than the area of ​​each space K1 on the proximal side of the middle portion shown in Fig. 3 (right side in Fig. 3).

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

[0051] As described above, in this embodiment, the first wires 51 forming the first spiral portion 50 are eight wires, namely, first wires 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h, and the second wires 61 forming the second spiral portion 60 are also eight wires, namely, second wires 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h, which are the same number.

[0052] As shown in FIG. 2, the catheter 10 is arranged so that at least the parallel contact portion 65 contacts the outer periphery of the inner layer 20, and is configured so that the outer layer 30 does not get 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.

[0053] In this embodiment, a parallel contact portion 65 consisting of two second wire rods 61, 61 is arranged so as to contact the outer periphery of the inner layer 20. As a result, a predetermined gap K2 is defined between the outer periphery of the inner layer 20 and the second wire rods 61, 61 that constitute the parallel contact portion 65, and the outer layer 30 does not enter the gap K2. Note that a first wire rod 51 is further arranged so as to contact the outer side (radially outer side) of the two second wire rods 61, 61.

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

[0055] In this embodiment, as described above, the parallel contact portions 65 have a knitting pattern in which they cross the first wire rod 51 so as to be alternately positioned outside and inside the first wire rod 51 (see paragraph 0046), and therefore, in the parallel contact portions 65, some portions contact the outer periphery of the inner layer 20 and some portions do not contact the outer periphery of the inner layer 20 along the spiral locus in the second spiral direction R2 of the second spiral portion 60. In other words, not all of the parallel contact portions 65 abut against the outer periphery of the inner layer 20, but rather, some abutting portions and some not abutting portions are alternately positioned along the spiral locus in the second spiral direction R2.

[0056] 1, the reinforcing member 40 is not disposed all the way to the very tip of the inner layer 20, but is disposed in a 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 disposed at the very tip of the outer layer 30. As a result, flexibility is ensured at the very tip of the catheter 10.

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

[0058] The first wire 51 of the first spiral portion 50 and the second wire 61 of the second spiral portion 60 constituting the reinforcing member 40 described above may be made of, for example, stainless steel, piano wire, or superelastic alloys such as Ni-Ti alloys, Ni-Ti-X (X = Fe, Cu, V, Co, Cr, Mn, Nb, etc.) alloys, Cu-Zn-X (X = Al, Fe, etc.) alloys, or radiopaque metals such as W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, and alloys thereof. In this embodiment, the first wire 51 and the second wire 61 are made of W.

[0059] The wire diameters of the first wire rod 51 and the second wire rod 61 are preferably 0.010 to 0.050 mm, and more preferably 0.015 to 0.030 mm. 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] (Variations) The shapes, structures, materials, layouts, etc. of the components that make up the catheter described above, such as the tube, inner layer, outer layer, reinforcing member, first spiral portion, and second spiral portion, are not limited to the above-described embodiments.

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

[0062] In addition, in this embodiment, the outer layer 30 has a shape in which layers 31, 32, 33, 34, and 35 of different hardness are arranged continuously in the axial direction, but the outer layer may also be a single layer made of the same material from the base end to the tip.

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

[0064] In addition, in this embodiment, the parallel contact portion 65 is formed by arranging two second wires 61 in parallel so that they are in contact with each other, but the number of second wires 61 that form the parallel contact portion may be three or more.

[0065] Furthermore, in this embodiment, the gap S2 between the parallel contact portions 65, 65 of the second spiral portion 60 is set wider than the gap S1 between the first wire rods 51, 51 of the first spiral portion 50, but the gap S2 may be narrower than the gap S1, or both gaps S1, S2 may be the same.

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

[0067] Furthermore, in this embodiment, the knitting pattern of the parallel contact portion 65 with respect to the first wire 51 is such that, in the traveling direction of the second spiral direction R2, the parallel contact portion 65 alternately crosses the first wire 51 at two points on the outside and inside of the first wire 51 (see FIG. 3 ). However, for example, the knitting pattern may be such that the parallel contact portion 65 alternately crosses the first wire 51 at one point on the outside and inside of the first wire 51.

[0068] Furthermore, in this embodiment, the gap S1 between the first wire rods 51, 51 of the first spiral portion 50 is wider at the base end side of the first spiral portion 50 than at the tip end side, but this gap S1 may be constant over the entire axial length from the base end to the tip end of the first spiral portion 50, or may be wider at the tip end side of the first spiral portion 50 than at the base end side, or may be gradually wider or narrower from the base end to the tip end of the first spiral portion 50.

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

[0070] (Operation and Effect) Next, an example of a method of using the catheter according to the present invention having the above-described structure, and its operation and effect will be described.

[0071] This catheter 10 is used to inject contrast agents, anticancer drugs, etc., or to place stents, etc., at predetermined locations in human tissues, such as blood vessels such as the hepatic artery, tubular organs of the human body such as the bile duct, pancreatic duct, ureter, and trachea, or body cavities. Note that the catheter 10 may also be used in locations other than those mentioned above, and the location of use is not particularly limited.

[0072] First, a contrast medium is administered into the body, and then the catheter 10 is guided and moved via a guide wire (not shown) using the well-known Seldinger technique or the like under X-ray fluoroscopy (radiofluorography).

[0073] In this case, it may be necessary to select and advance a specific small-diameter tubular organ from multiple small-diameter tubular organs branching off from a large-diameter tubular organ, which requires flexibility of the catheter 10. Furthermore, in order to ensure that a medicinal solution such as an anticancer drug reaches the affected area, the catheter 10 must be able to maintain its tube lumen without kinking, i.e., be kink-resistant.

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

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

[0076] Therefore, the above-mentioned requirements (maintaining kink resistance and improving flexibility) can be satisfied, and the catheter 10 can be suitably used, for example, in the treatment of liver cancer, when inserting the catheter 10 into the hepatic artery and injecting an anti-cancer agent into the liver through the hepatic artery.

[0077] Incidentally, in order to maintain the kink resistance of the catheter 10, it is conceivable to use, for example, a single thick wire as the second wire 61 forming 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 parallel contact portions 65 in which at least two second wires 61 forming the second spiral portion 60 are arranged in parallel so as to be in contact with each other. This allows the multiple wires to be grouped together and achieve the same kink resistance as when a single thick wire is used. This makes it possible to use thin wires that are more flexible than thick wires while maintaining kink resistance, and the flexibility of the catheter 10 can be increased by the gaps 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 and in contact can prevent the catheter 10 from becoming larger in the outer diameter direction. That is, as shown in Fig. 4, when the width (horizontal direction in Fig. 4) of the parallel contact portion 65 formed by the two second wires 61, 61 in contact with each other is compared to a single thick wire having the same outer diameter, the outer diameter direction dimension (meaning the vertical dimension in Fig. 4; see the arrow in Fig. 4) of the two second wires 61, 61 can be made smaller than the outer diameter of the single thick wire. As a result, the outer diameter of the catheter 10 can be made smaller.

[0080] 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 aspect, since the gap S2 is set as described above, it is possible to ensure a wide space K1 formed by the intersection of the second wire rod 61 of the second spiral portion 60 with the first wire rod 51 of the first spiral portion 50, thereby further increasing the flexibility of the catheter 10. Furthermore, the number of second wire rods 61 of the second spiral portion 60 in a predetermined region can be made closer to the number of first wire rods 51 of the first spiral portion 50, which also increases the flexibility of the catheter 10.

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

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

[0084] In addition, in this embodiment, the tube has an inner layer 20 and an outer layer 30 arranged outside the inner layer 20, and is arranged so that at least the parallel contact portion 65 contacts the outer periphery of the inner layer 20, and is configured so that the outer layer 30 does not get 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 (see Figure 2).

[0085] According to the above aspect, the outer layer 30 is configured so as not to get 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 can be displaced to a certain extent, thereby increasing the flexibility of the reinforcing member 40 and ultimately increasing the flexibility of the catheter 10.

[0086] Example A catheter of the example was manufactured having the same shape and structure as those shown in Figures 1 to 3. The first and second spiral portions 50, 60 were formed by winding eight first and second wire rods 51, 61, respectively.

[0087] (Comparative Example) A comparative catheter was manufactured in which the first and second spiral portions were formed by winding eight first and second wire rods, respectively, and the inclination angles θ1 and θ2 of the first and second wire rods relative to the catheter axis were the same as those in the example.Furthermore, the second wire rods were wound without contact with each other, with a gap in the axial direction, to form the second spiral portion.

[0088] (Flexibility Confirmation Test) As shown in Figure 5, the catheters of the Examples and Comparative Examples were each set in a known indentation load measurement tester 100. Each catheter was fixed so that its tip was 4 mm from the end face of the indentation load measurement tester 100. Then, an indentation load F was applied at a predetermined speed at a position 1 mm from the tip of each catheter, and the catheter was indented 0.5 mm. The repulsive load (resistance load) at this time was measured. This test was also performed three times for each catheter of the Examples and Comparative Examples.

[0089] The results are shown in Figure 6. In Figure 6, a smaller repulsion load indicates higher flexibility. As shown in Figure 6, the repulsion 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 distal end of each catheter of the Example and Comparative Examples was clamped in a U-shape using a measuring tool capable of clamping an object. The clamping force of the measuring tool was then gradually reduced, and the outer diameter was measured each time the clamping force reached a predetermined value. This test was performed three times for each catheter of the Example 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 device. 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 time) to the outer diameter of the catheter (initial outer diameter / outer diameter at measurement x 100). A decrease in this outer diameter retention rate can be said to indicate the occurrence of kinking.

[0092] As shown in Figure 7, the catheters of the example and the comparative example show almost the same tendency for the decrease in outer diameter retention, which indicates that the catheters of the example have almost the same kink resistance as the catheters of the comparative example.

[0093] It should be noted that the present invention is not limited to the above-described embodiment, 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.

[0094] REFERENCE SIGNS LIST 10 Catheter 20 Inner layer 30 Outer layer 40 Reinforcing member 50 First spiral portion 51 First wire rod 60 Second spiral portion 61 Second wire rod 65 Parallel contact portion

Claims

1. A catheter having a tube including a braided reinforcing member, The reinforcing member is a first spiral portion formed by winding a plurality of first wire rods in a first spiral direction with a predetermined gap between the first wire rods; a second spiral portion formed by winding a second wire in a second spiral direction different from the first spiral direction, the second spiral portion has parallel contact portions arranged in parallel so as to contact at least two of the second wire rods, and the parallel contact portions are configured by being woven so as to cross the first wire rods and be positioned on the outer and inner sides of the first wire rods, The parallel contact portion is composed of at least two sets: one set in which at least two of the second wires are arranged in parallel so as to be in contact with each other, and the other set in which at least two of the second wires different from the second wires constituting the first set are arranged in parallel so as to be in contact with each other, and the second spiral portion is formed by winding the sets together with a predetermined gap therebetween.

2. 2. The catheter according to claim 1, wherein the gap between the pairs of parallel contact portions of the second spiral portion is set wider than the gap between the plurality of first wires of the first spiral portion.

3. 3. The catheter according to claim 1, wherein the number of the first wires forming the first spiral portion is the same as the number of the second wires forming the second spiral portion.

4. The tube has an inner layer and an outer layer disposed outside the inner layer, the parallel contact portion is disposed so as to contact the outer periphery of the inner layer, 3. A catheter according to claim 1, wherein the outer layer is configured so as not to get between the outer periphery of the inner layer and the second wire rod constituting the parallel contact portion arranged in contact with the outer periphery.