JP5649131B2 - Medical tube and catheter using the same - Google Patents

Description

  The present invention relates to a medical tube inserted into a blood vessel or the like and a catheter using the same.

  2. Description of the Related Art Conventionally, medical tubes used for tubular organs such as blood vessels, digestive tracts, and ureters and catheters that are inserted into body tissues are used under radioscopy. For this reason, there is one in which the wire constituting the braid disposed inside the medical tube is made of a radiopaque metal, for example, tungsten (for example, see Patent Documents 1 and 2 below).

  Such a configuration using a radiopaque braid is advantageous in that the visibility of the entire medical tube can be improved.

  On the other hand, in order to improve the flexibility by reducing the rigidity of a part of such a medical tube, a resin having a low hardness is used as the resin covering the braid in the part to be made flexible. In addition, when the flexibility of the medical tube cannot be obtained simply by adjusting the hardness of the resin, the number of strands of the braid of the portion to be made flexible is reduced (for example, the following patents) Reference 2).

JP-T-2006-515778 US Pat. No. 7,833,218

  However, since the above-described medical tube requires radiopacity for the braided strands, there is a problem that the radiopacity deteriorates when the number of braided strands is reduced. In particular, since it is usually the distal end portion of the catheter that requires the flexibility of the medical tube, there is a problem in that the radiopacity of the distal end portion of the catheter deteriorates.

  The present invention has been made in view of such circumstances, and in a medical tube provided with a braid having a radiopaque strand, a part of flexibility can be obtained without degrading radiopacity. It is an object of the present invention to provide a medical tube that can be improved and a catheter using the medical tube.

  The above problems are solved by the means listed below.

<1> a tubular inner layer, a braid disposed on the inner layer, a plurality of first strands and second strands wound in a mesh shape, and at least the first strand being radiopaque; A wire piece formed by cutting the radiopaque first strand in the braid is a flexible braid portion positioned between the uncut second strand and the inner layer; and the braid and An outer layer covering the flexible braided portion, and the wire piece remains so as to straddle the second strand .

<2> The braid includes the second strand, which is a strong strand having a high mechanical strength, and the first strand , which is a weak strand having a low mechanical strength. The medical tube according to aspect 1, comprising a strand.

<3> The medical tube according to aspect 2, wherein the strong strand is wound in one direction and the weak strand is wound in the other direction.

<4> The medical tube according to aspect 2, wherein a difference in mechanical strength between the strong element wire and the weak element wire is configured by a difference in cross-sectional area.

<5> A catheter using the medical tube according to any one of aspects 1 to 4 as a catheter body.

<6> The catheter according to aspect 5, wherein the flexible braided portion is formed at a distal end portion of the catheter body.

<1> In the medical tube of the present invention, since the first strand is cut in the flexible braided portion, the flexible braided portion can improve the flexibility of the medical tube. Further, even if the first wire is cut, the flexible braid, radiopaque strand piece is located between the second wires and the inner layer that are not cut, and said second element Since it remains so as to straddle the wire, the radiopacity of the flexible braided portion can be improved by reducing the number of strands as compared with the conventional method of improving the flexibility. Moreover, since the 2nd strand which is not cut | disconnected exists also in a flexible braided part, the pushing characteristic of a medical tube can be improved. Here, the pushing characteristic refers to the ability to transmit the pushing force, which is the force for pushing the medical tube in the axial direction and inserting it into the body, from the proximal side to the distal side of the medical tube.

<2> The medical tube of Embodiment 2 of the present invention, the braid is composed of a second wire is a great strength wire of mechanical strength, the first wires are small weak wires mechanical strength The strand is made of a weak strand. Mechanical strength indicates the difficulty of cutting a strand, and includes the strand diameter, the cross-sectional area of the strand, the thickness of the strand (the length in the radial direction), the hardness of the material, and the like. With this configuration, it is possible to cut the other strand (weak strand) without cutting one strand (strong strand) using buffing or the like. An uncut strand for fixing this can be manufactured.

<3> In the medical tube according to aspect 3 of the present invention, the strong element wire according to aspect 2 is wound in one direction, and the weak element wire is wound in the other direction. For this reason, since the coil-shaped braid is formed without cutting the strong wire wound in one direction, the flexibility of the medical tube can be further improved.

<4> The medical tube according to aspect 4 of the present invention is configured such that the difference in mechanical strength between the strong wire and the weak wire in aspect 2 is based on the difference in cross-sectional area. Therefore, by performing polishing from the outer periphery of the medical tube using buffing or the like, without cutting the strong strand having a large cross-sectional area, the weak strand having a small cross-sectional area is cut, The uncut strand which fixes this can be manufactured easily.

<5> Aspect 5 of the present invention is a catheter using the above-described medical tube as a catheter body. Therefore, the catheter created in this way can improve the flexibility of the catheter body by the flexible braided portion. In addition, the flexible braided part can improve the radiopacity of the flexible braided part with a radiopaque strand compared to the conventional method of improving flexibility by reducing the number of braided wires. Can do. Further, since there is a strand that is not cut in the flexible braided portion, the pushing-in characteristic of the catheter can be improved.

<6> Since the flexible braided portion is formed at the distal end portion of the catheter body, the catheter according to the sixth aspect of the present invention can be configured so that the distal end of the catheter is more flexible. For this reason, the pushing characteristic of the catheter can be further improved.

FIG. 1 is an overall view of a catheter using the medical tube of the present embodiment. FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 shows a braid. FIG. 4 is a diagram showing a cross section taken along line AA of FIG. FIG. 5 is a view showing the flexible braided portion. FIG. 6 is a view showing a BB cross section of FIG. FIG. 7 is a diagram illustrating a process of forming the flexible braided portion. FIG. 8 is a view showing another embodiment of the braided wire.

The case where the medical tube of the present embodiment is a medical tube (hereinafter referred to as a catheter main body 40) constituting the main body of the catheter 10 will be described with reference to FIGS. The catheter 10 will be described as an example of a microcatheter for liver. 1, 2, and 5, the left side in the drawing is the distal side (tip side) inserted into the body, and the right side is the proximal side (rear end side, proximal side) operated by an operator such as a doctor. It is.
In each figure, members smaller than other portions such as the strands 26a and 26b of the braid 26 shown below are slightly exaggerated in relation to the dimensions of the other members for easy understanding. Is shown.

  The catheter 10 shown in FIG. 1 is a tubular medical device having a total length of about 1550 mm. The catheter 10 mainly includes a flexible catheter body 40, a tip 14 fixed to the distal end of the catheter body 40, and a connector 16 fixed to the proximal end of the catheter body 40.

  As shown in FIGS. 2 and 4, the catheter body 40 includes an inner layer 24, a braid 26 as a reinforcing member, an intermediate layer 27, and an outer layer 28 in order from the inside in the radial direction.

  The inner layer 24 is formed of a resin, and constitutes a lumen 29 for inserting a guide wire or other catheter therein. The resin material for forming the inner layer 24 is not particularly limited, but PTFE (polytetrafluoroethylene) is used in the present embodiment.

  A braid 26 as a reinforcing member is disposed on the surface of the inner layer 24. As shown in FIGS. 2 to 4, the braid 26 is formed by knitting a plurality of weak strands 26 a having low mechanical strength and strong strands 26 b having high mechanical strength into a mesh (mesh shape). The material of the weak wire 26a and the strong wire 26b is a radiopaque metal. In this embodiment, tungsten is used.

In the case of the present embodiment, the mechanical strength is the same for the weak strand 26a and the strong strand 26b, and the cross-sectional shapes of the strands 26a and 26b are both circular. It means the difference in diameter. The diameter of the strand is determined in consideration of the thickness of the catheter body 40. In the case of the present embodiment, the total when the two strands overlap is preferably in the range of about 0.03 mm to about 0.05 mm, and is set to about 0.04 mm. For this reason, the diameter of the weak strand 26a is about 0.010 mm, and the diameter of the strong strand 26b is about 0.030 mm.
Thus, by making the diameter (mechanical strength) of one strand smaller than the diameter (mechanical strength) of the other strand, as described later, even when the weak strand 26a having a small diameter is cut, It is possible to prevent the strong strand 26b having a large diameter from being cut.

  That is, the mechanical strength indicates the difficulty of cutting the strand, and in addition to the strand diameter, the sectional area of the strand, the thickness of the strand (the length in the radial direction), and the hardness of the material Etc.

  In the braid 26, a total of 16 (8 × 8) strands of 8 weak strands 26a and 8 strong strands 26b are alternately braided every 2 strands. That is, a weak strand 26a having a small diameter is wound in one direction, and a strong strand 26b having a large diameter is wound in the other direction. As shown in FIG. 3, in the case of the present embodiment, one pitch P in which one weak strand 26a or strong strand 26b wraps around the surface of the inner layer 24 is about 1.0 mm to about 1. A range of 5 mm is preferred and is set to about 1.0 mm.

In addition, the combination of the braided strands is not limited to 8 × 8 as described above. For example, not only symmetrical combinations such as 4 × 4 and 2 × 2 but also 4 Asymmetrical combinations such as x8, 2 x4, etc. can also be adopted.
Further, as described above, the method of alternately knitting a plurality of pieces, that is, every two pieces, is effective in holding a piece of strand 126a, which will be described later, with uncut strands 126b. You may use the braid woven in.

  The surface of the braid 26 is covered with an intermediate layer 27 made of resin. The resin material forming the intermediate layer 27 is not particularly limited, and polyamide, polyamide elastomer, polyester, polyurethane, or the like is used. In this embodiment, a polyamide elastomer is used.

  The surface of the intermediate layer 27 is covered with an outer layer 28. More specifically, the outer layer 28 covers a portion other than the length L (about 5.0 mm) from the distal end of the catheter body 40 constituting the flexible portion 15 described later. The outer layer 28 has a structure in which resin tubes of about 5 to 12 having different hardnesses are arranged on the intermediate layer 27 so as to be more flexible as being positioned at the distal end of the catheter 10 and are bonded by welding. In the case of the present embodiment, seven resin tubes 28 a to 28 g are arranged on the intermediate layer 27. The resin material of the outer layer 28 is not particularly limited, and polyamide, polyamide elastomer, polyester, polyurethane, or the like is used. In this embodiment, a polyamide elastomer is used.

  The catheter body 40 is reduced in diameter toward the distal end, and is divided into a small diameter portion 40a, a tapered portion 40b, and a large diameter portion 40c in order from the distal end side toward the rear end side.

The small diameter part 40a is a part in which the outer diameter and the inner diameter are made smaller than the large diameter part 40c. In the case of the present embodiment, the outer diameter of the small diameter portion 40a is preferably in the range of about 0.50 mm to about 0.70 mm, and is set to about 0.60 mm. In the present embodiment, the inner diameter is preferably in the range of about 0.35 mm to about 0.55 mm, and is set to about 0.45 mm.
The total axial length of the small diameter portion 40a is about 50 mm. Of the length in the axial direction of the small-diameter portion 40a, the portion of the tip length L (about 5.0 mm) is the flexible portion 15 described later, and the portion behind the flexible portion 15 is the outer layer 28 described above. This is a portion covered with the resin tube 28a located at the forefront of the resin tubes constituting the.

  A flexible portion 15 is formed at the tip of the small diameter portion 40a. In the present embodiment, the length L in the axial direction of the flexible portion 15 is preferably in the range of about 2.0 mm to about 5.0 mm, and is set to about 5.0 mm.

  FIG. 5 is a plan view showing the outer peripheral surface of the braid 26 of the flexible portion 15. FIG. 6 is a cross-sectional view taken along the line B-B of FIG. 5, that is, the flexible part 15 cut in the circumferential direction of the catheter body 40. As shown in FIGS. 5 and 6, in the flexible portion 15, the braid 26 constitutes a flexible braid portion 30. In the flexible braided part 30, the weak strand 26a with a small diameter located outside the strong strand 26b with a large diameter is in a cut state. This configuration is achieved by performing polishing to a position G sufficient to cut the diameter of the weak wire 26a having a small diameter from the outer surface to the inner surface of the braid 26 in a polishing process such as buff polishing described later. The By this process, the weak wire 26a having a small diameter located outside the strong wire 26b having a large diameter is removed by polishing. At this time, the cross-sectional shape of the strong strand 26b having a large diameter is maintained.

  On the other hand, although the weak strand 26a located inside the strong strand 26b is not removed by polishing, both ends are cut by the above-described polishing, so that a strand piece 126a remains inside the strong strand 26b. It becomes. Here, the strong strand 26b positioned outside the weak strand 26a is polished to have a non-circular strand 126b having a non-circular cross-sectional shape, but is continuous without being cut. Therefore, the position of the strand 126a is maintained while the strand 126a is pressed against the strand 126b.

  In this way, by cutting only the weak wire 26a having a small diameter and maintaining the strong wire 26b having a large diameter without cutting, the wire piece 126a does not deteriorate radiopacity, The flexibility of the flexible part 15 can be improved. Moreover, since the strong wire 26b is not cut | disconnected, it can prevent that the transmissibility of the pushing force of the catheter 10 deteriorates.

  A ring-shaped radiopaque marker 17 is attached to the outer periphery of the distal end of the flexible braided portion 30. In the present embodiment, the length of the marker 17 in the axial direction is set to about 0.5 mm. The material of the marker 17 is not particularly limited as long as it is radiopaque. In the present embodiment, a platinum alloy is used. The marker 17 also serves to position the strand 126a with the inner layer 24.

  In the flexible part 15, the flexible braided part 30 and the marker 17 are covered with resin, and constitute a flexible outer layer 18. The resin of the flexible outer layer 18 is not particularly limited, such as polyurethane or polyurethane elastomer, but a flexible resin having a lower hardness than the resin material of the outer layer 28 described above is used. In the case of the present embodiment, polyurethane, which is the same as the resin constituting the chip 14 described later, is used.

  The tapered portion 40b is a tapered portion that connects the small diameter portion 40a and the large diameter portion 40c. In the present embodiment, the length of the taper portion 40b in the axial direction is preferably in the range of about 50 mm to about 150 mm, and is set to about 100 mm. In the case of the present embodiment, the taper portion 40b is a portion covered with the resin tube 28b among the resin tubes constituting the outer layer 28 described above.

  The large diameter portion 40c constitutes a portion of the catheter body 40 other than the small diameter portion 40a and the tapered portion 40b. In the present embodiment, the outer diameter of the large diameter portion 40c is preferably in the range of about 0.90 mm to about 1.00 mm, and is set to about 0.90 mm. In the present embodiment, the inner diameter is preferably in the range of about 0.50 mm to about 0.65 mm, and is set to about 0.55 mm. In the case of the present embodiment, the large diameter portion 40c is a portion covered with the resin tubes 28c to 28g among the resin tubes constituting the outer layer 28 described above.

The tip 14 is attached to the distal end of the catheter body 40, that is, the distal end of the flexible portion 15. The tip 14 is a cylindrical member that forms the distal end opening 14 a of the catheter 10. The outer periphery of the tip of the tip 14 is provided with an arc-shaped taper. In the present embodiment, the total length of the tip 14 in the axial direction is preferably in the range of about 0.50 mm to about 1.0 mm, and is set to about 0.5 mm.
The outer diameter and inner diameter of the tip 14 are equivalent to the small diameter portion 40 a of the catheter body 40.

  The chip 14 is made of only resin. The resin on which the chip 14 is formed is not particularly limited, but is made of polyurethane, polyurethane elastomer or the like. In the case of the present embodiment, polyurethane is used. This resin contains a radiopaque powder. In the case of the present embodiment, it is preferable to contain a radiopaque powder in the range of about 65 w% to about 90 w%, and about 85 w% tungsten powder is contained. Bismuth etc. are used as another radiopaque powder.

Next, a method for manufacturing the flexible portion 15 described above will be described with reference to FIG.
First, a catheter body 40 including an inner layer 24, a braid 26, an intermediate layer 27, and an outer layer 28 disposed on a core metal 60 is prepared (FIG. 7A). In this state, the distal end portion of the catheter body 40 is in a state where the intermediate layer 27 that is not covered by the outer layer 28 is exposed in order to form the flexible portion 15.

The resin of the exposed intermediate layer 27 is removed as much as possible by brush polishing or the like, and the braid 26 is exposed (FIG. 7B). Thereafter, polishing is performed to a position G where the diameter of the weak strand 26a having a small diameter can be cut by buffing or the like. Thereby, the weak strand 26a with a small diameter located outside the strong strand 26b with a large diameter is cut and removed. Further, the weak strand 26a having a small diameter located inside the strong strand 26b having a large diameter remains in a state of remaining as a strand piece 126a. The outer portion of the strong strand 26b is ground to a strand 126b having a non-circular portion. Therefore, the strand piece 126a is pressed against the strand 126b having a non-circular portion made of a continuous large-strength strand 26b without being cut, and is held in that position. As a result, the flexible braided portion 30 is formed.
The intermediate layer 27 is removed by adjusting the pressing force of buffing without using brush polishing, and the weak strand 26a having a small diameter located outside the strong strand 26b having a large diameter is cut. You can also.

Next, the ring-shaped marker 17 is attached to the tip of the flexible braided portion 30.
Further, the flexible braided portion 30 and the marker 17 are covered with a resin tube constituting the flexible outer layer 18 of the flexible portion 15 and welded (FIG. 7C).
By covering the flexible braided portion 30 with the flexible outer layer 18 in this way, the strand 126a is securely fixed inside the strand 126b having a non-circular portion made of the strong strand 26b.

Next, after extracting the metal core 60, the tip 14 is formed by welding a resin tube constituting the tip 14 to the tip of the flexible portion 15.
This operation is performed, for example, by inserting a resin tube constituting the chip 14 into an unillustrated mold and then pressing and welding the flexible portion 15 to the resin tube while heating in the mold.

  A connector 16 is attached to the rear end of the catheter body 40. When a liquid medicine such as a contrast medium is supplied from a syringe (not shown) attached to the connector 16, the liquid medicine is discharged from the distal end opening 14 a through the lumen 29.

  Based on the above configuration, the operation of the present embodiment will be described by taking as an example the case where the catheter 10 using the catheter body 40 (medical tube) of the present embodiment is used as a microcatheter for the liver.

  A guide catheter (not shown) and a guide wire (not shown) are inserted in advance into the artery of the liver where the treatment target site is located, and the catheter 10 is inserted into the body along the guide wire. Is done. The guide wire is inserted from the distal end opening 14 a of the tip 14 of the catheter 10, passes through the lumen 29, and extends from the rear end of the connector 16.

When the catheter 10 is advanced in the blood vessel along the guide wire, an operator such as a doctor pushes the catheter 10 into the body while pushing the catheter 10 in the axial direction from the proximal side or rotating the catheter 10 by a predetermined angle. Let me insert it. At this time, since the braid 26 is formed by knitting strands 26a and 26b having different diameters in a mesh shape (mesh shape), the indentation characteristic is higher than that of a coil-shaped reinforcing member in which the strands are wound in one direction. Is expensive. Here, the pushing characteristic refers to the ability to transmit the pushing force, which is a force for pushing the catheter in the axial direction and inserting it into the body, from the proximal side to the distal side of the catheter.
Further, in the flexible part 15 at the distal end of the catheter body 40, the strong strand 26b wound in one direction becomes a strand 126b whose partial cross-sectional area is reduced by polishing, but is cut. There is no continuous state. For this reason, it is prevented that the indentation characteristic deteriorates in the flexible portion 15.

  Further, in the flexible braid 30, the weak strand 26 a having a small diameter wound in the other direction is cut, but the radiopaque strand 126 a is held by the flexible braid 30. It is in the state. For this reason, it can prevent that the radiopacity of the flexible braid part 30 deteriorates.

Therefore, under radioscopy, the operator uses the braid 26 including the radiopaque strands 26a and 26b and the strand 126b and the strand piece 126a in the flexible portion 15 as clues for the entire image of the catheter 10. Can be recognized. Further, the tip of the catheter 10 can be recognized by the marker 17 attached to the flexible portion 15. Further, since the tip 14 contains a radiopaque powder, the tip position of the catheter 10 can be known also by the tip 14.
Further, since the tip 14, the marker 17, the flexible part 15 having the wire piece 126a, and the braid 26 at the rear end of the flexible part 15 have different radiopaque visibility, the operator can The operation can be performed while recognizing the exact position of the catheter 10 by using the difference in visibility of radiopaque as a clue.

After the operator positions the catheter 10 at the target site based on the above-described radiopaque member under radioscopy, the operator removes the guide wire from the connector 16 and is connected to the connector 16 (not shown). The contrast agent and the therapeutic agent are released from the syringe.
Thereafter, the catheter 10 is pulled out of the body, and the procedure is completed.

In the manufacturing method of the flexible portion 15 in the embodiment described above, the intermediate layer 27 of the flexible portion 15 is removed as much as possible by brushing or the like, and the exposed flexible braided portion 30 is covered with the flexible outer layer 18. . This method is effective in increasing the flexibility of the flexible portion 15 by increasing the thickness of the flexible outer layer 18 made of a flexible resin.
However, the effect of the present embodiment can be obtained only by removing the range in which the intermediate layer 27 is removed to a position G sufficient to cut the weak wire 26a having a small diameter. In this case, since the strand piece 126a located inside can be held by the remaining intermediate layer 27, it is effective in firmly holding the strand piece 126a.
Accordingly, the flexible braided portion 30 may be covered with the intermediate layer 27 and further covered with the outer layer 28 in the same manner as the braid 26 other than the flexible braided portion 30.

In the embodiment described above, the catheter body 40 is composed of the inner layer 24, the braid 26, the intermediate layer 27, and the outer layer 28. However, the intermediate layer is eliminated, and the braid disposed on the inner layer is directly formed by the outer layer. It is good also as a structure covered.
That is, both the flexible braid portion 30 and the other braid 26 can be covered only with the outer layer.

  In the embodiment described above, the resin that forms the outer layer 28 on the rear end side of the chip 14 including the flexible outer layer 18 of the flexible portion 15 does not contain a radiopaque powder. Such a configuration is effective in recognizing the chip 14, the flexible portion 15, and the rear end portion by the difference in radiopaque visibility as described above. However, the resin forming the flexible outer layer 18 and the outer layer 28 may contain a radiopaque powder.

In the embodiment described above, the weak wire 26a and the strong wire 26b having different circular diameters are used for the strands constituting the braid 26. Such a configuration has an advantage that the visibility can be improved by increasing the proportion of the radiopaque portion while the thickness of the catheter is limited. Further, it is advantageous in cutting the weak strand 26a having a small diameter without cutting the strong strand 26b having a large diameter to form the strand 126a. However, it is not always necessary that the cross sections having different diameters of both the strands are circular strands. For example, even if the cross-sectional area is the same, if the length in the radial direction of one strand is shorter than the length in the radial direction of the other strand, the shorter strand is cut, so the same effect Can be obtained.
Further, the strand wound in at least one direction may be a so-called flat wire having a substantially rectangular cross section. The example shown in FIG. 8 shows an example in which the braided portion 226 has a large cross-sectional area that is not easily cut and is a strong wire 226b that is a flat wire, and a small cross-sectional area that is easily cut and has a weak wire 226a that is a round wire.
In addition, as shown in FIG. 8, the cross section is substantially rectangular, as shown in FIG. 8, the cross-sectional shape of the wire is not only a rectangle having four corners at right angles, but also four corners having arc shapes or portions corresponding to side edges. Means an arcuate shape.

  In the embodiment described above, the weak strand 26a that is easily cut is wound in one direction, and the strong strand 26b that is difficult to cut is wound in the other direction. This configuration is advantageous in improving the push-in characteristic of the catheter 10 and improving the flexibility by forming a coiled braid with the strong strands 26b that are not cut. However, in order to improve the radiopacity by the strand 126a, the weak strand and the strong strand do not necessarily have to be wound in different directions, and the weak strand and the strong strand are meshed (mesh May be combined.

  In the embodiment described above, the weak wire 26a and the strong wire 26b are both made of radiopaque tungsten as a material. Such a configuration is preferable for improving the visibility of the entire catheter body 40. However, in order to obtain the effect of the present embodiment, it is sufficient that the weak strand 26a constituting the strand piece 126a is radiopaque. Therefore, the weak strand 26a is made of a radiopaque material, and strong. The braid may be configured using the wire 26b as a radiation transmissive material.

  In the embodiment described above, the weak strand 26a having a small mechanical strength (diameter) and the strong strand 26b having a large mechanical strength (diameter) are used. With this configuration, the other strand (weak strand 26a) is cut without cutting one strand (strong strand 26b) by a method such as buffing, and is easily cut from the strand 126a. The unexposed wire 126b is manufactured. However, since it is possible to cut only one strand by using a laser or the like, the strands do not necessarily have different mechanical strengths. That is, a braid using strands having the same mechanical strength may be used.

  In the embodiment described above, the flexible portion 15 having the flexible braided portion 30 is provided at the distal end portion of the catheter main body 40 (medical tube), but the distal end portion is not necessarily required. You may provide the flexible part 15 which has the flexible braided part 30 in an intermediate part or a rear-end part.

In the embodiment described above, the catheter 10 is applied to a liver microcatheter. However, the catheter of the present embodiment is not limited to a microcatheter, and may be a guiding catheter, a contrast catheter, or the like. Applicable to other types of catheters. Further, the organ to be treated is not limited to the liver, and can be used for various organs such as the heart and the brain.
Furthermore, the medical tube of the present embodiment can be used for a medical tubular member other than the catheter body.

10 Catheter 14 Tip 18 Flexible outer layer 24 Inner layer 26 Braid 26a Weak strand 26b Strong strand 28 Outer layer 30 Flexible braided portion 40 Catheter body 126a Strand piece 126b Uncut strand

Claims (6)

A tubular inner layer;
A braid disposed on the inner layer, wherein a plurality of first strands and second strands are wound in a mesh, and at least the first strand is radiopaque;
A wire piece formed by cutting the radiopaque first strand in the braid is a flexible braid portion positioned between the uncut second strand and the inner layer,
An outer layer covering the braid and the flexible braid part , and
The medical tube , wherein the strand piece remains so as to straddle the second strand . The braid is composed of the second strand that is a strong strand having a high mechanical strength and the first strand that is a weak strand having a low mechanical strength, and the strand is formed from the weak strand. The medical tube according to claim 1, wherein The medical tube according to claim 2, wherein the strong element wire is wound in one direction and the weak element wire is wound in the other direction. The medical tube according to claim 2, wherein a difference in mechanical strength between the strong element wire and the weak element wire is constituted by a difference in cross-sectional area. A catheter using the medical tube according to any one of claims 1 to 4 as a catheter body. The catheter according to claim 5, wherein the flexible braided portion is formed at a distal end portion of the catheter main body.

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