WO2023112984A1 - Catheter - Google Patents

Abstract

A catheter 1 is a periphery insertion type central venous catheter, said catheter 1 comprising a catheter main body 11 and a stylet 12 that is inserted through the catheter main body 11, wherein the stylet 12 has a projection part 122 that has a tip end portion 121A which is more flexible than an intermediate portion 121B and a base end portion 121C and that projects from an opening 112A of a tip 112 of the catheter main body 11.

Description

catheter

The present disclosure relates to a peripherally inserted central venous catheter.

Conventionally, catheters have been used as a type of medical device for examining and treating body tubular tissues such as blood vessels. For example, a peripheral vein insertion type central venous catheter (PICC) is used, which is inserted from a peripheral vein such as an upper arm and positioned at a central vein near the heart at the time of infusion or the like. Since PICC can deliver drugs to thick blood vessels near the heart, phlebitis and the like due to drugs are less likely to occur. On the other hand, when placing a PICC, it is necessary to insert it from a vein in the upper arm and push it over a long distance to reach the superior vena cava. Although stiffness is necessary to push the catheter forward, there is a problem that if the catheter itself is hardened, the damage to the blood vessel increases. Therefore, the catheter itself is made relatively soft and combined with a guide wire or stylet to provide the necessary stiffness for insertion and pushing.

For example, as a method of inserting a catheter using a guidewire, the Seldinger method is known, in which the guidewire is first indwelled in the blood vessel, and the catheter is inserted into the blood vessel along the inserted guidewire. However, in a PICC inserted from a peripheral blood vessel, the total length of the guide wire is as high as about 150 cm, and the total length of the catheter is also as high as about 60 cm. Therefore, in the case of PICC, the technique of the Seldinger method is complicated.

In addition, since the stylet inserted into the catheter is less flexible than the guidewire, the tip of the stylet should not protrude from the catheter so as not to damage the inner wall of the blood vessel. However, if the stylet tip does not protrude from the catheter, the catheter tip directly contacts the inner wall of the vessel. A catheter made of resin is soft, but if it has an edge at its tip, it may damage the inner wall of the blood vessel by contact. In particular, the length of the catheter may be adjusted by severing the tip, which presents a sharp edge at the tip and thus risks perforation.

Patent Document 1 discloses a stylet for a central venous catheter having a bending portion made of synthetic resin at its tip. In the stylet of Patent Document 1, the bent portion is made of a synthetic resin that is softer than metal, so it is expected that even if the distal end including the bent portion protrudes from the distal end of the catheter, the inner wall of the blood vessel can be prevented from being damaged. be done.

JP-A-2003-164529

However, the stylet of Patent Document 1 has a maximum length of about 20 cm. Therefore, in the case of a centrally inserted central venous catheter to be inserted into a large vein, the stylet described in Patent Document 1 can be used. However, it is difficult to use such a stylet in PICC, which is longer than the above-mentioned catheter and is inserted from a narrow peripheral blood vessel.

Therefore, the present disclosure makes it possible to realize a PICC that has the necessary stiffness for insertion and can suppress the risk of perforation of the inner wall of the blood vessel.

In order to solve the above problems, one aspect of the catheter disclosed herein is a peripheral vein insertion type central vein catheter, comprising a catheter body and a stylet inserted through the catheter body, The stylet has a tip that is softer than the rest of the stylet and has a projection projecting from the distal end of the catheter body.

In one aspect of the catheter according to the present disclosure, the stylet is inserted into the catheter body and inserted into the blood vessel. Therefore, it is possible to omit the troublesome operation of inserting the catheter main body after inserting the guide wire into the blood vessel first, and to ensure the necessary stiffness and resistance to breakage when inserting the catheter. In addition, since the protruding portion of the stylet protrudes from the distal end of the catheter body, the protruding portion serves as a guide during insertion of the catheter, reducing the risk of perforation of the blood vessel. Furthermore, since the tip of the stylet is more flexible than the rest of the stylet, the risk of damaging the blood vessel with the tip of the stylet can be reduced.

It is preferable that the stylet has a core made of a metal wire, and the diameter of the tip of the core is smaller than the diameter of the rest of the core.

According to this configuration, since the flexibility of the tip of the stylet can be adjusted by adjusting the diameter of the core material, the risk of perforation of the blood vessel can be effectively reduced while sufficiently ensuring necessary stiffness and resistance to breakage. can be provided in a convenient manner.

The tip of the stylet may have a coil shape.

According to this configuration, the risk of blood vessel perforation can be effectively reduced.

It is preferable that the stylet includes a resin layer covering the core material, and that the outer diameter of the stylet is substantially constant over the entire length of the core material.

In this configuration, since the diameter of the tip portion of the core material is smaller than the diameter of the other portion of the core material, the resin layer is thicker at the tip portion of the stylet than at the other portion of the stylet. The outer diameter of the stylet is substantially constant over the entire length of the core. According to this configuration, it is possible to ensure sufficient flexibility at the distal end of the stylet and sufficient strength of the entire stylet. In this specification, the term "substantially constant outer diameter" means that the difference between the outer diameter and the maximum outer diameter is within 20% of the maximum outer diameter.

The length of the projecting portion of the stylet is preferably 10 mm or more and 50 mm or less.

If the length of the protruding portion of the stylet is less than the lower limit, the tip of the catheter body may come into contact with the inner wall of the blood vessel if the stylet bends slightly. If the length of the protruding portion of the stylet exceeds the upper limit, the tip of the catheter body may inadvertently enter, for example, the heart when the catheter is placed in a blood vessel. There is a possibility that it will not be placed in position. By setting the length of the projecting portion of the stylet within the above range, the risk of perforation of the blood vessel can be effectively reduced, and a catheter with excellent handleability can be provided.

The length of the catheter body is preferably 40 cm or longer.

According to this configuration, it can be suitably used as a peripheral vein insertion type central vein catheter.

As described above, according to the present disclosure, it is possible to omit the complicated operation of inserting the catheter main body after inserting the guide wire into the blood vessel first, and to provide the necessary stiffness and resistance to breakage when inserting the catheter. can be secured. In addition, the projecting portion of the stylet serves as a guide when inserting the catheter, and the risk of perforation of the blood vessel can be reduced. Furthermore, since the tip of the stylet is more flexible than the rest of the stylet, the risk of damaging the blood vessel with the tip of the stylet can be reduced.

FIG. 2 illustrates a catheter according to one embodiment; FIG. 2 is a cross-sectional view taken along line AA of FIG. 1; Fig. 10 shows a stylet; 4 is a cross-sectional view of the stylet body; FIG. 1 is a schematic diagram of the apparatus used for the tip load measurement test; FIG.

Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. The following description of preferred embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its applicability or its uses.

<Catheter>
FIG. 1 is a general view of a peripherally inserted central venous catheter 1 according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line AA of FIG.

The catheter 1 is a medical device that is introduced from a peripheral vein, inserted into the superior vena cava, and left in place to inject drug solutions into the central vein, collect blood, measure venous pressure, and the like. In this specification, the blood vessel insertion side of the catheter 1 is referred to as the distal side or tip side, and the hand side operated by the operator is referred to as the proximal side or base end side.

As shown in FIGS. 1 and 2, the catheter 1 includes a catheter body 11 and a stylet 12 inserted through the catheter body 11.

≪Catheter body≫
The catheter body 11 is a tubular member having a double lumen structure. Note that the catheter body 11 is not limited to the double lumen structure, and may have a single lumen structure, a triple lumen structure, or the like.

The length of the catheter body 11 can be appropriately set in consideration of the length from the catheter insertion site such as a human extremity or coronary artery to the affected area. It has a length from the apex to the affected part of the superior vena cava. Specifically, the length of the catheter body 11 is preferably 40 cm or longer.

As shown in FIG. 1, the catheter body 11 includes a shaft 111, a distal tip 112, a Y tube portion 113, a first branch tube 114 and a second branch tube 115, a first port 114A and a second port 115A. , a first clamp 114B and a second clamp 115B.

-shaft-
The shaft 111 is a flexible, elongated tube, and as shown in FIG. 2, has a first lumen 111A and a second lumen 111B that are independent passages.

A side-hole type opening 111C is provided on the distal end side of the shaft 111 . The second lumen 111B opens at the opening 111C.

The specific structure of the shaft 111 is not particularly limited. The shaft 111 may be made of one or more biocompatible resin materials such as polyurethane, polyethylene, polyester, polypropylene, polyether block amide, polyamide, polytetrafluoroethylene, and polyvinylidene fluoride. The shaft 111 may be formed of a single layer of the resin material, or may be formed of multiple layers. The shaft 111 is formed of a plurality of layers of the resin material, and a mesh-like cylindrical braided body made of metal such as stainless steel or Ni—Ti alloy or resin is embedded between the layers. A laminated structure or the like may also be used. Furthermore, the shaft 111 may be divided into a plurality of sections in the longitudinal direction, and different resin materials may be used for each of the plurality of sections. In this case, from the viewpoint of improving the ability to pass through thin, meandering blood vessels, the distal end side portion of the shaft 111 may be formed using a material that is more flexible than the proximal end side portion.

Further, for example, a contrast agent such as bismuth oxide, bismuth sulfate, bismuth subcarbonate, or tungsten may be added to the molding resin layer of the shaft 111, or stainless steel, gold, platinum, or the like may be added to the outer peripheral surface of the shaft 111 or between layers. Contrast markers or the like made of iridium or the like may be provided. As a result, it is possible to secure visibility with X-rays during surgery.

- tip -
The distal tip 112 is a tubular member provided at the distal end of the shaft 111 and constitutes the distal end of the catheter body 11 .

The proximal end of the distal tip 112 has substantially the same outer and inner diameter dimensions as the distal end of the shaft 111 and is integrally connected with the distal end of the shaft 111 . The proximal end of the lumen of the distal tip 112 communicates with the first lumen 111A, and the distal end forms an endhole-shaped opening 112A (the distal end of the catheter main body).

The distal tip 112 may be integrally molded with the shaft 111, or may be formed separately from an appropriate resin material and fixed to the distal end of the shaft 111 by adhesion, welding, or the like. Distal tip 112 may be formed of a single layer or multiple layers of the same material as shaft 111 . Note that the distal tip 112 is preferably made of a material that is more flexible than the shaft 111 from the viewpoint of reducing the risk of blood vessel perforation.

Also, in the distal tip 112, similarly to the shaft 111, a contrast agent may be blended in the molding material, or a contrast marker or the like may be provided on the outer peripheral surface or between the layers. This allows the distal end of the catheter body 11 to be visually recognized under X-ray fluoroscopy.

-Y tube part-
The Y tube portion 113 is provided at the proximal end of the shaft 111 and is a tubular member having two independent lumens that are continuous with each of the first lumen 111A and the second lumen 111B. The Y tube part 113 is a resin molded body such as polyurethane, and can serve as a handle for inserting and removing the catheter 1, for example.

－Branches, Ports and Clamps－
The first branch tube 114 and the second branch tube 115 are tubular members connected to the proximal end of the Y tube portion 113 .

The lumen of the first branch tube 114 communicates with the lumen of the Y tube portion 113 connected to the first lumen 111A. A first port 114A is provided at the proximal end of the first branch tube 114 . A first clamp 114B is provided between the Y tube portion 113 and the first port 114A of the first branch tube 114 .

The lumen of the second branch tube 115 communicates with the lumen of the Y tube portion 113 connected to the second lumen 111B. The proximal end of the second branch tube 115 is provided with a second port 115A. A second clamp 115B is provided between the Y tube portion 113 of the second branch tube 115 and the second port 115A.

-Distal Lumen and Proximal Lumen-
First lumen 111A of shaft 111, the lumen of distal tip 112, the lumen of Y tube 113 connected to first lumen 111A, and the lumens of first branch tube 114 and first port 114A provide distal lumens are configured.

A proximal lumen is formed by the second lumen 111B of the shaft 111, the lumen of the Y tube portion 113 connected to the second lumen 111B, and the lumens of the second branch tube 115 and the second port 115A. there is

The catheter 1 is of an over-the-wire type, and the stylet 12 is passed through the distal lumen through the first port 114A. That is, the inner diameter of the distal lumen is set to a diameter that allows the stylet 12 to be inserted. In addition, a low-friction resin such as PTFE (polytetrafluoroethylene) may be applied to the inner peripheral surface of each member constituting the distal lumen. As a result, the coefficient of friction of the inner peripheral surface can be reduced, so that the insertability of the stylet 12 is improved.

In addition, the proximal lumen is a space through which fluids such as a contrast medium, physiological saline, and air can flow.

Note that the catheter 1 is not limited to the over-the-wire type, and may have other known structures such as a rapid exchange type.

≪Stylet≫
The catheter 1 is inserted into a blood vessel with the stylet 12 inserted into the distal lumen of the catheter main body 11 and a protruding portion 122 described later protruding from the opening 112A. That is, the stylet 12 is longer than at least the distal lumen of the catheter body 11 .

According to this configuration, it is possible to omit complicated operations such as inserting the guide wire into the blood vessel first and then inserting the catheter main body as in the Seldinger method, and the stiffness and stiffness required when inserting the catheter 1 can be omitted. It is possible to ensure the resistance to breakage.

As shown in FIGS. 1 and 3, the stylet 12 has a stylet body 121 and a protective member 129. As shown in FIGS.

-Protective material-
The protective member 129 is provided at the proximal end of the stylet body 121 and constitutes the proximal end of the stylet 12 . The protective member 129 is, for example, a columnar or plate-like member that is gripped by the operator to operate the stylet 12 . The protective member 129 is made of, for example, polypropylene, polycarbonate, vinyl chloride, or the like.

-Stylet Body-
The stylet main body 121 is a wire material having a higher rigidity than the shaft 111, and has a certain degree of elasticity so that it can be held in its original shape and can be restored to its original shape even after being deformed. As a result, the necessary stiffness and resistance to breakage when inserting the catheter 1 can be ensured.

The outer diameter dimension of the stylet body 121 is set sufficiently smaller than the inner diameter dimension of the distal lumen. The length of stylet body 121 is configured such that the overall length of stylet 12 is longer than the distal lumen of catheter body 11 .

As shown in FIG. 4 , the stylet body 121 includes a core material 123 and a resin layer 125 covering the core material 123 . The core material 123 is made of metal wire such as stainless steel or Ni--Ti alloy. The resin layer 125 is made of fluorine resin such as PTFE, PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), ETFE (ethylene-tetrafluoroethylene copolymer), polyurethane, hydrophilic coating, or the like. The resin layer 125 is provided to ensure slipperiness when the stylet 12 is passed through the distal lumen, but may not be provided. Note that the core material 123 may be formed of a metal having contrast enhancement properties. Also, a contrast marker may be provided between the core material 123 and the resin layer 125 . This allows the stylet 12 to be visible under X-ray fluoroscopy.

In addition, as shown in FIG. 4, it is preferable that the tip and base ends of the core material 123 are also covered with the resin layer 125 so that the tip of the core material 123 is not exposed. The length of only the resin layer 125 located on the distal side of the distal end of the core material 123 and the proximal side of the proximal end of the core material 123 is the thickness of the resin layer 125 covering the distal end portion 123A of the core material 123, which will be described later. , and is preferably equal to or greater than the thickness of the resin layer 125 covering the base end portion 123C of the core member 123, which will be described later. According to this configuration, since the core material 123 exists over almost the entire length of the stylet body 121, the catheter 1 is more flexible than when the distal end portion 121A of the stylet body 121 is made of only resin. Improves insertability. In addition, when the core material 123 is made of a metal having contrast properties, the visibility of the tip position of the stylet 12 under X-ray fluoroscopy is improved. It should be noted that the portion where only the resin layer 125 is present, that is, the distal end and the proximal end of the stylet body 121 is desirably chamfered and rounded by polishing or the like so as to eliminate corners.

As shown in FIG. 1, the stylet body 121 has a projecting portion 122 that projects distally from the opening 112A of the distal tip 112 when the stylet 12 is inserted through the distal lumen. As a result, when the catheter 1 is inserted into a blood vessel, the projecting portion 122 serves as a guide, and the risk of perforation of the blood vessel by the distal tip 112 of the catheter main body 11 can be reduced.

It should be noted that the length of the projecting portion 122 is preferably 10 mm or more and 50 mm or less.

If the length of the projecting portion 122 is less than the lower limit, the distal end of the tip 112 of the catheter body 11 may come into contact with the blood vessel when the stylet 12 is slightly bent. If the length of the protruding portion 122 exceeds the upper limit, there is a possibility that the tip 112 will not be placed at an appropriate position when the catheter 1 is left in the blood vessel. By setting the length of the protruding portion 122 within the above range, the risk of perforation of the blood vessel can be effectively reduced, and the catheter 1 with excellent handleability can be provided.

Further, as shown in FIGS. 3 and 4, the stylet body 121 includes a distal end portion 121A, an intermediate portion 121B, and a proximal end portion 121C. The intermediate portion 121B and the base end portion 121C are other portions of the stylet body 121 . A portion of the distal end portion 121A, that is, a portion on the distal side may constitute the projecting portion 122, or the entire distal end portion 121A may constitute the projecting portion 122. FIG. In addition, distal portions of the distal end portion 121A and the intermediate portion 121B may constitute the projecting portion 122 .

Here, the distal end portion 121A is formed to be more flexible than the intermediate portion 121B and the proximal end portion 121C.

Specifically, the diameter of the distal end portion 123A of the core member 123 is preferably smaller than the diameters of the other portions of the core member 123, that is, the intermediate portion 123B and the proximal portion 123C. The diameters of the portion 123B and the tip portion 123A are configured to gradually decrease in this order. As a result, the distal end portion 121A of the stylet body 121 is more flexible than the intermediate portion 121B and the proximal end portion 121C. Thereby, when the catheter 1 is inserted into the blood vessel, the risk of the tip portion 121A damaging the blood vessel can be reduced.

In addition, by adjusting the diameter of the core material 123, the flexibility of the distal end portion 121A can be adjusted. Therefore, the risk of perforation of the blood vessel can be effectively reduced while sufficiently ensuring the stiffness and resistance to breakage required when the catheter 1 is inserted. can be reduced to

The outer diameter of the stylet body 121 is substantially constant over the entire length of the core material 123 . That is, since the diameter of the distal end portion 123A of the core material 123 is smaller than the diameters of the intermediate portion 123B and the proximal end portion 123C, the distal end portion 121A of the stylet body 121 has a larger resin layer 125 than the intermediate portion 121B and the proximal end portion 121C. As a result, the outer diameter of the stylet body 121 is substantially constant over the entire length of the core member 123 . According to this configuration, it is possible to ensure sufficient flexibility at the distal end portion 121A of the stylet body 121 and to ensure sufficient strength of the stylet body 121 as a whole.

It should be noted that the load on the distal end portion 121A of the stylet 12 measured by a distal end load measurement test described later is preferably 30 gf or less. Moreover, the load is more preferably 20 gf or less, and particularly preferably 2 gf or less. By setting the load of the distal end portion 121A within this range, the perforation risk of the blood vessel can be effectively reduced. Also, the lower limit of the load applied to the distal end portion 121A of the stylet 12 is not intended to be particularly limited, but can be set to, for example, 0.1 gf or more.

A bent portion 127 is provided on the distal end side of the tip portion 121A. That is, the tip shape of the stylet 12 is an angle type. Note that the stylet 12 is not limited to the angle type, and may have other tip shapes such as a straight type and a J type.

The length of the bent portion 127 can be, for example, about 10 mm, but is not particularly limited. In addition, although the bent portion 127 is described as linear, it may be curved. Further, the portion of stylet body 121 on the proximal side of bending portion 127 may be straight or curved. When both the bent portion 127 and the proximal portion are linear, the angle formed by the bent portion 127 and a straight line parallel to the proximal portion is not particularly limited, but is, for example, 10°. It can be about 40°. Alternatively, for example, the entire stylet body 121 may be formed with a large radius of curvature, and only the distal end portion 121A may be provided with a bent portion 127 having a small radius of curvature. Furthermore, a plurality of bent portions may be provided at different positions in the length direction of the distal end portion 121A. That is, the shape of the stylet main body 121 is not limited in any way, and can be designed and changed as appropriate according to the patient's blood vessel shape and the like.

Also, the stylet in which the core material 123 is covered with the resin layer 125 has been described, but the stylet is not limited to such a configuration as long as the tip portion is more flexible than the other portions. For example, the stylet may be configured to have a core and a coil wire formed therearound. In this case, the flexibility of each part can be adjusted by adjusting the thickness of the core material, the thickness of the coil wire, the density of the coil wire, and the like. Moreover, although the entire stylet can be coil-shaped, only a portion including the distal end portion can be coil-shaped. Also, the tip of the stylet covered with the resin layer may be coil-shaped.

－Tip load measurement test－
A tip load measurement test was performed using the device 3 shown in FIG. 5 to evaluate the flexibility of the tips of three types of stylets and guidewires. Table 1 shows the results.

The sample of Experimental Example 1 is the stylet 12 of the catheter 1 according to the present disclosure, the core material 123 is a Ni-Ti alloy wire, and the resin layer 125 is a hydrophilic coating. The diameter of the intermediate portion 123B is configured to gradually decrease from the proximal end portion 123C toward the distal end portion 123A. The diameter of the stylet body 121 is approximately 0.36 to 0.45 mm. The tip shape of the stylet body 121 is an angle type, which will be described later, and is inclined at about 20°.

The sample of Experimental Example 2 is a stylet included in a commercially available PICC kit, made of stainless steel, and has a diameter of about 0.5 mm. The shape of the tip is straight. The stylet is used in such a manner that the tip thereof does not protrude from the distal end of the catheter body during operation of the catheter.

The sample of Experimental Example 3 is a stylet included in a commercially available PICC kit, made of stainless steel, and has a diameter of 0.4 mm. The shape of the tip is straight. As with the sample of Experimental Example 2, the stylet is used in a state in which the tip thereof does not protrude from the distal end of the catheter body during operation of the catheter.

The sample of Experimental Example 4 is a commercially available guide wire made by coating a Ni-Ti alloy wire with a urethane resin and a hydrophilic coating. The guide wire has a diameter of about 0.97 mm and a straight tip.

The length of the stylet and guidewire of each sample is 50 cm or longer.

As shown in FIG. 5, the device 3 has a support portion 31 that supports the sample S and a base 34. The sample S was fixed to the support portion 31 so that the tip portion of the sample S protruded from the support portion 31 toward the base 34 by about 20 mm. 5, the supporting portion 31 is moved toward the base 34, and the tip of the sample S is placed on the base 34 on a 1 mm-thick silicone rubber sheet 33 (having a hardness of 50). °). The load [gf] required to push the tip of the sample S 1 mm after contact with the surface of the silicone rubber sheet 33 was measured. Each sample of Experimental Examples 1 to 4 was measured three times.

As shown in Table 1, the load of the sample of Experimental Example 1 is smaller than the load of the samples of Experimental Examples 2 to 4, and the tip of the sample of Experimental Example 1 is the tip of the sample of Experimental Examples 2 to 4. was found to be more flexible than

As described above, the stylets of Experimental Examples 2 and 3 are used in a state in which the tip does not protrude from the distal end of the catheter body. Therefore, the catheter is relatively rigid in order to have stiffness, and it is found that the flexibility is greatly inferior to that of the guide wire of Experimental Example 4. That is, the stylets of Experimental Examples 2 and 3 have the risk of perforation of the blood vessel, and cannot be used with the tip protruding from the distal end of the catheter body.

On the other hand, the distal end of the stylet of Experimental Example 1 is sufficiently soft even compared to the distal end of the guidewire of Experimental Example 4. Therefore, even if the tip of the stylet protrudes from the distal end of the catheter body, the risk of perforation of the blood vessel by the tip of the stylet is effectively reduced.

Although the embodiments of the present disclosure have been described above, the present disclosure is not to be construed in a limited manner by specific descriptions in such embodiments, and various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art. It is possible to implement in a mode in which

The catheter of the present disclosure is extremely useful in the medical field.

1 catheter 11 catheter body 112A opening (distal end of catheter body)
12 Stylet 121 Stylet main body 121A (of stylet main body) Distal portion 121B (of stylet main body) Middle portion 121C (of stylet main body) Proximal portion (of stylet main body) 122 Protruding portion 123 Core material 123A Distal portion (of core material) 123B Intermediate part 123C (of core material) Base end part 125 (of core material) Resin layer 127 Bent part 129 Protective member 3 Apparatus 31 (for tip load measurement test) Support part 33 Silicone rubber sheet 34 Base S Sample

Claims (6)

A peripherally inserted central venous catheter, comprising:
a catheter body;
a stylet inserted through the catheter body,
The catheter of claim 1, wherein the stylet has a tip that is softer than the rest of the stylet and has a projection projecting from the distal end of the catheter body. The stylet has a core made of a metal wire,
The catheter of claim 1, wherein the diameter of the tip of the core is smaller than the diameter of the rest of the core. The catheter according to claim 1 or 2, wherein the tip of the stylet has a coil shape. The stylet includes a resin layer covering the core material,
3. The catheter of claim 2, wherein the outer diameter of the stylet is substantially constant over the length of the core. The catheter according to any one of claims 1 to 4, wherein the protruding portion of the stylet has a length of 10 mm or more and 50 mm or less. The catheter according to any one of claims 1 to 5, wherein the catheter body has a length of 40 cm or more.

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