JP2024072397A - catheter - Google Patents

Abstract

To provide a catheter high in visibility of the tip part under radioscopy, and high in periphery reachability.SOLUTION: A catheter 1 includes a tube body having an inner layer 10, an outer layer 30, and a reinforcement body 20 disposed outside the inner layer 10, which braids a plurality of strands 25 including radiopaque strands 26 and 27. The tube body includes a marker part 23 including a multi-row coil wound in a coil form with at least two strands 25 including the radiopaque strands 26 and 27 made parallel to each other more on a tip side than the reinforcement body 20. In the marker part 23, the pitch angle of the strands 25 is smaller than the pitch angle of the strands 25 in the reinforcement body 20.SELECTED DRAWING: Figure 5

Description

The present invention relates to a catheter for use within a lumen such as a blood vessel.

Intravascular therapy is used to diagnose and treat lesions that have developed in blood vessels by inserting a device percutaneously into the blood vessel under radiographic guidance. In intravascular therapy, catheters are used as devices to deliver drugs and guide wires to the lesion.

Because catheters must pass through the branches and curves of small blood vessels to reach the periphery, they are required to have a small tip, improved flexibility, and high pushability. In addition, because it is necessary to grasp the catheter's position within the blood vessel under fluoroscopy, the tip must be highly visible.

Patent Document 1 discloses a catheter equipped with a marker formed by winding a radiopaque metal wire on the leading end of a reinforcing layer made of a braided linear body. Patent Document 2 discloses a catheter equipped with a marker formed by winding a radiopaque wire adjacent to the leading end of a reinforcing layer made of braided metal wire. Patent Document 3 discloses a catheter having a braid in which multiple wires, at least one of which is radiopaque, are wound, and the pitch of the braid is reduced at the tip to form a marker braid.

JP 2008-229160 A JP 2006-218085 A JP 2012-196275 A

A catheter in which a marker is placed on the reinforcing layer has a large outer diameter at the part where the marker is placed and has high rigidity, which impedes peripheral reachability. On the other hand, a catheter in which a marker is placed distal to the reinforcing layer has only a resin layer at the boundary between the marker and the reinforcing layer, making the catheter more likely to break or kink at the boundary. In addition, a catheter with a marker formed by braiding wires has higher rigidity than a coiled marker. A marker formed by braiding wires has poorer visibility under radioscopy than a coiled marker, because the proportion of radiopaque wires in the total wires contained in the marker is small.

The present invention has been made to solve the above-mentioned problems, and aims to provide a catheter whose tip is highly visible under radioscopy and has high peripheral reachability.

To achieve the above object, (1) a catheter has a tubular body including an inner layer, an outer layer, and a reinforcing body arranged on the outside of the inner layer and braided with a plurality of strands including radiopaque strands, the tubular body has a marker section on the distal side of the reinforcing body, the marker section including a multi-strand coil in which at least two strands including the radiopaque strands are wound in a coil shape in a parallel state, the pitch angle of the strands in the marker section being smaller than the pitch angle of the strands in the reinforcing body.

The catheter configured as described above has a coil-shaped marker portion, which provides high visibility under radioscopy. In addition, the marker portion and the reinforcing body are arranged in the same layer without overlapping each other. This allows the catheter to have a small diameter and flexibility at its tip. Furthermore, the radiopaque wire forming the marker portion is arranged continuously from the reinforcing body to the marker portion. This prevents the boundary between the marker portion and the reinforcing body from being made of resin only, making it less likely for the catheter to break or kink at the boundary. As described above, the catheter can provide high visibility of the tip portion under radioscopy and high peripheral reachability.

(2) In the catheter of (1) above, the number of wires forming the marker portion may decrease from the base end to the tip end of the tubular body. This allows the marker portion to have an increased flexibility from the base end to the tip end, allowing for a smooth transition in stiffness along the longitudinal axis of the catheter.

(3) In the catheter of (2) above, the marker section may be a tightly wound coil in which the wires forming the marker section are wound so as to be in close contact with each other. As a result, the pitch angle of each wire at the tip end of the marker section, where the number of wires is reduced, is smaller than that at the base end. This improves the flexibility of the catheter at the tip end of the marker section.

(4) In the catheter of (2) above, the pitch of each of the wires in the marker section may be constant along the length of the tube. This reduces the amount of metal contained per unit length at the tip end where the number of wires is reduced, thereby reducing the rigidity of the marker section. This improves the flexibility of the catheter at the tip end of the marker section.

(5) In any of the catheters (1) to (4) above, the wires forming the marker portion may be arranged at equal intervals along the circumferential direction of the tubular body at the tip of the reinforcing body. This reduces the anisotropy of stiffness in the portion of the catheter where the reinforcing body is located and at the boundary between the reinforcing body and the marker portion, so that the pushing force or torque applied by the operator to the base end of the catheter is transmitted evenly to the tip of the catheter. As a result, the catheter has good operability and is less likely to break or kink at the boundary between the reinforcing body and the marker portion.

1 is an overall view of a catheter according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a portion of a tubular body of the catheter. This is a cross-sectional view taken along line AA in FIG. FIG. 4 is an enlarged front view showing a portion of the reinforcing body. 4 is an enlarged front view of the reinforcing member and the marker portion near the tip of the tube. FIG. FIG. 2 is a conceptual structural diagram of a braiding machine. 10A and 10B are diagrams illustrating a process of cutting the wire at the tip of the reinforcing body, in which FIG. 10A shows the state before cutting, and FIG. 10B shows the state after cutting. 13A to 13C are diagrams illustrating a wire cutting process according to a first modified example. 13A to 13C are diagrams illustrating a wire cutting process according to a second modified example. 13A to 13C are diagrams illustrating a wire cutting process according to a third modified example. 13 is an enlarged front view of a reinforcing member and a marker portion near the tip of a tube having a marker portion according to a first modified example. FIG. 13 is an enlarged front view of a reinforcing member and a marker portion near the tip of a tube having a marker portion according to a second modified example. FIG. This is an enlarged front view of the reinforcing body and the marker portion near the tip of the tube when the radiopaque wire is wound in multiple strands in the reinforcing body.

Below, an embodiment of the present invention will be described with reference to the drawings. Note that dimensions in the drawings may be exaggerated for convenience of explanation and may differ from the actual dimensions. Furthermore, in this specification and the drawings, components having substantially the same functional configuration are given the same reference numerals to avoid duplicated explanation. In this specification, the side of the catheter that is inserted into the blood vessel will be referred to as the "tip side" and the side that is operated will be referred to as the "base side".

In the explanation of this specification, the direction in which the catheter extends in its natural state (straight state without the application of external force) is referred to as the "longitudinal direction". The direction of rotation about the longitudinal direction of the catheter as the reference axis is referred to as the "circumferential direction". In addition, the side of the catheter that is inserted into the blood vessel is referred to as the distal end, and the end opposite the distal end is referred to as the proximal end. In addition, the part including a certain range in the longitudinal direction from the distal end (the most distal end) is referred to as the "distal portion", and the part including a certain range in the longitudinal direction from the proximal end (the most proximal end) is referred to as the "proximal portion".

In this specification, the range "X to Y" includes X and Y and means "greater than or equal to X and less than or equal to Y."

The catheter 1 according to this embodiment is a device that is percutaneously inserted into a blood vessel and used for treatment or diagnosis within the blood vessel. As shown in FIG. 1, the catheter 1 has a long tubular body 2 having a distal end and a proximal end, a hub 3 connected to the proximal end of the tubular body 2, and a kink-resistant protector 4 that surrounds the connection site between the tubular body 2 and the hub 3.

As shown in FIG. 2, the tube 2 is a flexible tubular member, and a lumen 5 is formed inside from the base end to the tip end. A guide wire is inserted into the lumen 5 when the catheter 1 is inserted into a blood vessel. The lumen 5 can also be used as a passage for a contrast agent, a therapeutic agent, an embolic substance, or a medical instrument.

The effective length of the tube body 2 is not particularly limited, but is, for example, 1300 mm or more and 1500 mm or less. The effective length of the tube body 2 is the length of the portion that can be inserted into a blood vessel or a sheath. In this embodiment, the effective length is the length from the tip of the anti-kink protector 4 to the tip of the tube body 2.

The hub 3 is fixed liquid-tightly to the base end of the tubular body 2 by adhesive, heat fusion, or a fastener (not shown). The hub 3 functions as an insertion port for a guidewire or medical instrument into the lumen 5, and as an injection port for a contrast agent, therapeutic agent, or embolic material into the lumen 5. The hub 3 also functions as a grip when operating the catheter 1.

The hub 3 is formed from a resin such as, but not limited to, polycarbonate, polyamide, polysulfone, polyarylate, or methacrylate-butylene-styrene copolymer.

The kink-resistant protector 4 is provided to surround the connection between the tube body 2 and the hub 3, and prevents kinking of the tube body 2 at the connection between the tube body 2 and the hub 3. The kink-resistant protector 4 is made of an elastic material such as natural rubber or silicone resin.

As shown in Figures 2 and 3, the tube 2 includes an inner layer 10, a reinforcing body 20 disposed on the outside of the inner layer 10, and an outer layer 30 disposed on the outside of the inner layer 10 and the reinforcing body 20. The outer surface of the outer layer 30 may be coated with a low-friction material such as a hydrophilic polymer.

The inner layer 10 is a tubular member having a lumen 5 inside. The inner layer 10 is made of a low-friction material such as a fluorine-based resin such as polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE).

The outer layer 30 is a tubular member that covers the outside of the inner layer 10 and the reinforcing body 20. The hardness of the outer layer 30 increases stepwise or gradually from the tip to the base end. Therefore, the bending stiffness of the tube body 2 is low at the tip and high at the base end.

The outer layer 30 is formed from a thermoplastic resin such as a polymer material, such as polyolefin (polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these), polyvinyl chloride, polyamide, polyester elastomer, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, or fluororesin, or a mixture of these, or a thermosetting resin such as an epoxy resin.

As shown in Figures 2 to 4, the reinforcing body 20 is formed by braiding a plurality of strands 25 on the outer surface of the inner layer 10 into a tubular shape with gaps. The reinforcing body 20 is made up of 16 strands 25 braided together. In the reinforcing body 20, the strands 25 are braided in a mesh shape so that they cross each other. Of the 16 strands 25 that make up the reinforcing body 20, two are a first radiopaque strand 26 and a second radiopaque strand 27.

The first radiopaque wire 26 and the second radiopaque wire 27 are preferably arranged at equal intervals along the circumferential direction of the tube 2 in a cross section perpendicular to the longitudinal direction of the catheter 1 at the tip of the reinforcing member 20. As shown in FIG. 3, in this embodiment, the first radiopaque wire 26 and the second radiopaque wire 27 are arranged to face each other on the outer surface of the inner layer 10 in a cross section perpendicular to the longitudinal direction of the catheter 1.

The wire 25 that transmits radiation is made of a metal wire such as stainless steel, resin fiber, carbon fiber, glass fiber, etc. The first radiopaque wire 26 and the second radiopaque wire 27 that do not transmit radiation are made of a metal wire made of gold, platinum, silver, iridium, tungsten, tantalum, or an alloy of these, or a resin fiber containing radiopaque particles such as barium sulfate or bismuth oxide.

The reinforcing member 20 has a braid pitch P0, which is the center distance between adjacent wires 25 forming the braid, of 50 μm or more and 500 μm or less. The cross-sectional shape of the wires 25 including the radiopaque wires 26 can be circular, rectangular, or the like, and multiple cross-sectional shapes may be used in combination. When the cross-sectional shape of the wires 25 is circular, the outer diameter is 10 μm or more and 100 μm or less, more preferably 30 μm or more and 60 μm or less. When the cross-sectional shape of the wires 25 is rectangular, the width is 30 μm or more and 60 μm or less, and the thickness is 10 μm or more and 20 μm or less.

As shown in FIG. 5, the tube 2 has a marker portion 23 at the tip side of the reinforcing body 20. The marker portion 23 is a multi-strand coil formed of a first radiopaque strand 26 and a second radiopaque strand 27 that form the reinforcing body 20. The multi-strand coil is a coil formed by spirally winding a plurality of strands 25 in parallel. Of the strands 25 that form the reinforcing body 20, the first radiopaque strand 26 and the second radiopaque strand 27 that form the marker portion 23 extend from the tip of the reinforcing body 20 to the tip side of the tube 2, forming a multi-strand coil on the outside of the inner layer 10. On the other hand, the other strands 25 that do not form the marker portion 23 terminate at the tip of the reinforcing body 20. As a result, the first radiopaque strand 26 and the second radiopaque strand 27 are provided continuously from the reinforcing body 20 to the marker portion 23. In the marker portion 23, the first radiopaque strand 26 and the second radiopaque strand 27 form a tightly wound multi-strand coil in which the adjacent first radiopaque strand 26 and second radiopaque strand 27 are in close contact with each other without crossing each other. Therefore, the pitch P2 of each strand 25 (the first radiopaque strand 26 and the second radiopaque strand 27) forming the marker portion 23 is smaller than the pitch P1 of the reinforcing body 20. In addition, the pitch angle D2 of each strand 25 forming the marker portion 23 is smaller than the pitch angle D1 of the reinforcing body 20.

The length of the marker portion 23 can be 0.2 mm or more and 1.5 mm or less. The length of the marker portion 23 may be outside this range.

In the catheter 1, the first radiopaque wire 26 and the second radiopaque wire 27 are continuous at the boundary between the marker portion 23 and the reinforcing body 20. As a result, the boundary between the marker portion 23 and the reinforcing body 20 of the catheter 1 is not only made of resin, and the catheter 1 is less likely to break or kink at the boundary. In addition, the first radiopaque wire 26 and the second radiopaque wire 27 are arranged so as to face each other on the outer surface of the inner layer 10 in a cross section perpendicular to the longitudinal direction of the catheter 1. As a result, the catheter 1 has small anisotropy in rigidity at the portion where the reinforcing body 20 is arranged and at the boundary between the marker portion 23 and the reinforcing body 20, so that the pushing force or torque applied by the operator to the base end side of the catheter 1 is transmitted to the tip side of the catheter 1 without bias. As a result, the catheter 1 has good operability and is less likely to break or kink at the boundary between the marker portion 23 and the reinforcing body 20.

The marker section 23 is a tightly wound coil in which the pitch of the radiopaque wires 26 and 27 is smaller than that of the reinforcing body 20, resulting in high visibility under radioscopy. In addition, the pitch angle D2 of the wires 25 in the marker section 23 is smaller than the pitch angle D1 of the wires 25 in the reinforcing body 20, resulting in high flexibility of the tip of the catheter 1.

The marker portion 23 is arranged so that the base end of the marker portion 23 is adjacent to the tip of the reinforcement body 20. The marker portion 23 and the reinforcement body 20 are arranged in the same layer without overlapping each other. This makes the tip of the catheter 1 small in diameter and flexible. Note that the base end of the marker portion 23 does not have to be arranged adjacent to the tip of the reinforcement body 20. For example, another member, such as a tubular body made of metal or resin, may be arranged between the base end of the marker portion 23 and the tip of the reinforcement body 20.

Of the wires 25 forming the reinforcing body 20, the tips of the wires 25 that terminate at the tip of the reinforcing body 20 are arranged in a spiral pattern along the circumferential direction. That is, the tip surface 20a formed by connecting the tips of the wires 25 that terminate at the tip of the reinforcing body 20 along the circumferential direction is inclined with respect to the longitudinal axis direction of the catheter 1. Therefore, the catheter 1 can reduce the gap between the base end surface of the marker portion 23, around which the first radiopaque wire 26 and the second radiopaque wire 27 are wound in a spiral pattern, and the tip surface of the reinforcing body 20. The tip surface 20a of the reinforcing body 20 may be perpendicular to the longitudinal axis direction of the catheter 1.

The marker portion 23 may be loosely wound, with adjacent wires 25 spaced apart, or may include both tight and loose windings from the tip to the base end of the marker portion 23. The pitch and pitch angle of the wires 25 forming the marker portion 23 may vary from the tip to the base end of the marker portion 23.

Of the wires 25 forming the reinforcing body 20, the wires 25 forming the marker portion 23 may be three or more. The wires 25 forming the marker portion 23 are wound in the same direction in the reinforcing body 20. Therefore, when the number of wires 25 forming the reinforcing body 20 is 2n, the number of wires 25 forming the marker portion 23 can be up to n. The wires 25 forming the marker portion 23 may include at least one radiopaque wire 25. In addition, all of the wires 25 forming the marker portion 23 may be radiopaque wires 25.

Next, a method for manufacturing the reinforcing body 20 and the marker portion 23 will be described. First, the wire 25 including the core 45 covered with the inner layer 10, the first radiopaque wire 26, and the second radiopaque wire 27 is set in the braiding machine 40.

As shown in FIG. 6, the reinforcing body 20 is braided on the outer surface of the inner layer 10 by a braiding machine 40. The braiding machine 40 has a first rotating body 41 and a second rotating body 42 that are ring-shaped and have a common rotation center axis, and is configured to be able to send out a core bar 45 coated with the inner layer 10 along the rotation center axis of the first rotating body 41 and the second rotating body 42. The first rotating body 41 and the second rotating body 42 each have eight bobbins 43 along the circumferential direction. The 16 strands 25 are held in each bobbin 43. The first rotating body 41 and the second rotating body 42 rotate in opposite directions, and each bobbin 43 of the first rotating body 41 and the second rotating body 42 alternately repeats an action of approaching and moving away from the inner layer 10. As a result, the strands 25 are braided so as to cross other strands 25 on the outer surface of the inner layer 10 sent out, forming the reinforcing body 20. The first radiopaque strand 26 and the second radiopaque strand 27 are held in two of the 16 bobbins 43, and the reinforcing body 20 braided on the outer surface of the inner layer 10 can include the first radiopaque strand 26 and the second radiopaque strand 27.

The wires 25 braided on the outer surface of the inner layer 10 are removed from the tip of the reinforcement body 20, except for the wires 25 (the first radiopaque wire 26 and the second radiopaque wire 27) that form the marker portion 23. Since the ends of the wires 25 tend to spread outward in the radial direction, it is necessary to apply a treatment to suppress the spread of the wires 25 at the tip of the reinforcement body 20 before removing the wires 25 other than the wires 25 that form the marker portion 23. The spread of the wires 25 can be suppressed by applying heat to the tip region T of the reinforcement body 20 surrounded by a dashed line in FIG. 7(a) to anneal it and lose the elasticity of the wires 25. The treatment to suppress the spread of the wires 25 may be the application of an adhesive to the tip region T of the reinforcement body 20.

As shown in FIG. 8, the spread of the wires 25 may be suppressed by covering the reinforcement body 20 from the tip end toward the base end with an outer layer 30 before removing the wires 25 other than those forming the marker portion 23.

As shown in FIG. 9, the spread of the wires 25 may be suppressed by welding the wires 25 at the position that will become the tip of the reinforcement body 20 together before removing the wires 25 other than the wires 25 that form the marker portion 23. The weld point R is formed at the position where the wires 25 overlap each other.

After performing a treatment to suppress the spread of the strands 25 at the tip of the reinforcing body 20, the strands 25 are removed from the tip side of the tip of the reinforcing body 20, except for the strands 25 (the first radiopaque strands 26 and the second radiopaque strands 27) that form the marker portion 23, as shown in FIG. 7(b). The strands 25 can be removed by any method, such as cutting with a blade or by metal fatigue, or by melting with heat.

The removal of the wires 25 other than the wires 25 forming the marker portion 23 may be performed by electrolytic processing. As shown in FIG. 10, the electrolytic processing device 50 has an electrolytic cell 51 that stores an electrolytic solution 53 and a holding portion 52 that holds the reinforcing body 20. Among the wires 25 that form the reinforcing body 20, the wires 25 that form the marker portion 23 (the first radiopaque wire 26 and the second radiopaque wire 27) have an insulating coating on their surfaces. On the other hand, the wires 25 that do not form the marker portion 23 do not have an insulating coating on their surfaces. The reinforcing body 20 formed by such wires 25 is immersed in the electrolytic solution 53, and the reinforcing body 20 is used as the cathode and an electrode (not shown) in the electrolytic solution 53 is used as the anode to pass electricity through the electrolytic solution 53, whereby the portion of the wires 25 that do not have an insulating coating that is immersed in the electrolytic solution 53 is removed. The wires 25 that form the marker portion 23 are not passed electricity through the electrolytic solution 53 because they have an insulating coating on their surfaces, and are not removed. This allows the wires 25 other than those forming the marker portion 23 to be removed.

After removing the portion of the wire 25 that does not form the marker portion 23 that is located further forward than the tip of the reinforcement body 20, the wire 25 that forms the marker portion 23 is wound in a coil shape on the outer surface of the inner layer 10 further forward than the reinforcement body 20 to form the marker portion 23. After the reinforcement body 20 and the marker portion 23 are formed, the outside of the reinforcement body 20 and the marker portion 23 are covered with the outer layer 30. This allows the tube body 2 to be formed.

The number of strands 25 in the marker section 23 may decrease from the base end to the tip end of the tube body 2. As shown in FIG. 11, the first portion 23a of the marker section 23 on the base end side adjacent to the reinforcing body 20 is a densely wound multi-strand coil formed of a first radiopaque strand 26 and a second radiopaque strand 27. The first radiopaque strand 26 terminates at a position between the tip and base end of the marker section 23. The second portion 23b of the marker section 23, which is distal to the position where the first radiopaque strand 26 terminates, is a single-strand coil wound with only the second radiopaque strand 27. In the marker section 23, the pitch P3 of the second radiopaque strand 27 in the second portion 23b is smaller than the pitch P2 of the second radiopaque strand 27 in the first portion 23a.

As shown in FIG. 11, the marker portion 23 is a tightly wound coil in which the second portion 23b is wound so that the second radiopaque wires 27 are in close contact with each other. Therefore, in the marker portion 23, the pitch angle D3 of the second radiopaque wires 27 in the second portion 23b is smaller than the pitch angle D2 of the second radiopaque wires 27 in the first portion 23a. This makes the second portion 23b of the marker portion 23 more flexible than the first portion 23b. Therefore, the catheter 1 can further increase the flexibility of the tip portion of the tubular body 2. In addition, the marker portion 23 can change the rigidity at the tip portion of the tubular body 2 in a stepwise manner, so that the rigidity can be smoothly transitioned along the longitudinal direction at the tip portion of the catheter 1.

In the marker portion 23, the pitch of each wire 25 forming the marker portion 23 may be constant along the length direction of the tube body 2. As shown in FIG. 12, the first radiopaque wire 26 terminates at a position between the tip and base ends of the marker portion 23. The pitch P3' of the second radiopaque wire 27 in the second portion 23b is equal to the pitch P2' of the second radiopaque wire 27 in the first portion 23a. Therefore, the second portion 23b of the marker portion 23 is a sparsely wound coil in which the second radiopaque wires 27 are spaced apart from each other. The second portion 23b of the marker portion 23 has a lower rigidity because the amount of metal contained per unit length is reduced compared to the first portion 23a. Therefore, the catheter 1 has improved flexibility on the tip side of the marker portion 23.

When the marker portion 23 is made up of three or more wires 25, the number of wires 25 forming the marker portion 23 may decrease by one as it moves from the base end to the tip of the tubular body 2, or multiple wires may decrease at the same time. In addition, it is preferable that the wires 25 forming the tip of the marker portion 23 are radiopaque wires 25. This allows the catheter 1 to ensure visibility of the tip under radioscopy.

As shown in FIG. 13, the first radiopaque strand 26 and the second radiopaque strand 27 may be wound in a spiral shape in a parallel state in the reinforcement 20. The first radiopaque strand 26 and the second radiopaque strand 27 wound in a parallel state in the reinforcement 20 are wound on the outer surface of the interior 10 on the tip side of the reinforcement 20 while maintaining the parallel state, forming the marker portion 23.

As described above, the catheter 1 according to the present embodiment (1) is a catheter 1 having a tube including an inner layer 10, an outer layer 30, and a reinforcing body 20 arranged outside the inner layer 10 and braided with a plurality of strands 25 including radiopaque strands 26, 27. The tube has a marker section 23 including a multi-strand coil wound in a coil shape with at least two strands 25 including the radiopaque strands 26, 27 in parallel on the distal side of the reinforcing body 20, and the pitch angle of the strands 25 in the marker section 23 is smaller than the pitch angle of the strands 25 in the reinforcing body 20. The catheter 1 thus configured has a high visibility under radioscopy because the marker section 23 is coil-shaped. In addition, the marker section 23 and the reinforcing body 20 are arranged in the same layer without overlapping each other. This makes the distal end of the catheter 1 small in diameter and flexible. Furthermore, the radiopaque strands 26, 27 forming the marker section 23 are arranged continuously from the reinforcing body 20 to the marker section 23. As a result, the boundary between the marker portion 23 and the reinforcing body 20 of the catheter 1 is not made of only resin, and the catheter 1 is less likely to break or kink at the boundary. As described above, the catheter 1 can achieve high visibility of the tip under radioscopy and high peripheral reachability.

(2) In the catheter 1 described above in (1), the number of wires 25 forming the marker portion 23 may decrease from the base end of the tubular body toward the tip. This allows the marker portion 23 to have an increased flexibility from the base end toward the tip, allowing for a smooth transition in stiffness along the longitudinal direction at the tip of the catheter 1.

(3) In the catheter 1 of (2) above, the marker portion 23 may be a tightly wound coil in which the radiopaque wires 26, 27 forming the marker portion 23 are wound in close contact with each other. As a result, the pitch angle of each of the radiopaque wires 26, 27 at the tip end of the marker portion 23, where the number of wires 25 is reduced, is smaller than that at the base end. As a result, the catheter 1 has improved flexibility at the tip end of the marker portion 23.

(4) In the catheter 1 of (2) above, the pitch of each wire 25 in the marker portion 23 may be constant along the length of the tube. This reduces the amount of metal contained per unit length at the tip end of the marker portion 23 where the number of wires 25 is reduced, thereby reducing the rigidity. As a result, the catheter 1 has improved flexibility at the tip end of the marker portion 23.

(5) In any of the catheters 1 described above in (1) to (4), the wires 25 forming the marker portion 23 may be arranged at equal intervals along the circumferential direction of the tube at the tip of the reinforcing body 20. This reduces the anisotropy of rigidity of the catheter 1 at the portion where the reinforcing body 20 is arranged and at the boundary between the reinforcing body 20 and the marker portion 23, so that the pushing force or torque applied by the operator to the base end side of the catheter 1 is transmitted evenly to the tip side of the catheter 1. As a result, the catheter 1 has good operability and is less likely to break or kink at the boundary between the reinforcing body 20 and the marker portion 23.

The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical concept of the present invention.

REFERENCE SIGNS LIST 1 Catheter 2 Tube body 3 Hub 4 Anti-kink protector 5 Lumen 10 Inner layer 20 Reinforcement body 23 Marker portion 23a First portion 23b Second portion 25 Wire 26 Radiopaque wire 27 Radiopaque wire 30 Outer layer 40 Braiding machine 41 First rotating body 42 Second rotating body 43 Bobbin 45 Core metal 50 Electrochemical processing device 51 Electrolytic cell 52 Holding portion 53 Electrolyte

Claims (5)

A catheter having a tubular body including an inner layer, an outer layer, and a reinforcing body disposed outside the inner layer and braided with a plurality of strands including a radiopaque strand,
The tubular body has a marker portion on the distal end side of the reinforcing body, the marker portion including a multi-filament coil in which at least two of the wires including the radiopaque wire are wound in a coil shape in a parallel state,
A catheter in which the pitch angle of the wire in the marker portion is smaller than the pitch angle of the wire in the reinforcing member. The catheter according to claim 1, wherein the number of wires forming the marker portion decreases from the base end of the tubular body toward the tip end. The catheter according to claim 2, wherein the marker portion is a tightly wound coil in which the wires forming the marker portion are wound so as to be in close contact with each other. The catheter according to claim 2, wherein the pitch of each of the wires in the marker section is constant along the length of the tube. The catheter according to any one of claims 1 to 4, wherein the wires forming the marker portion are arranged at equal intervals along the circumferential direction of the tubular body at the tip of the reinforcing member.

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