Catheter

Abstract

To improve flexibility of a catheter distal end portion.SOLUTION: A catheter includes: a hollow shaft; a distal end side marker provided in a distal end portion of the shaft; a rear end side marker provided in the distal end portion of the shaft and located further in a rear end side than the distal end side marker; a distal end side tube covering an outer periphery of the distal end side marker; and a rear end side tube covering an outer periphery of the rear end side marker. A rear end of the distal end side tube and a distal end of the rear end side tube are provided while being spaced from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a catheter. [Background technology]

[0002] Conventionally, a method for treating an aneurysm using a catheter has been known. Patent Document 1 describes a catheter having two markers at its tip that can be seen by the surgeon under X-ray fluoroscopy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-77305 A Summary of the Invention [Problem to be solved by the invention]

[0004] The tip of the catheter needed to be flexible to facilitate its progression through the blood vessel.

[0005] An object of the present invention is to improve the flexibility of the tip portion of a catheter. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) One form of the present invention is a catheter comprising a hollow shaft, a distal marker provided at the distal end of the shaft, a rearward marker provided at the distal end of the shaft and positioned rearward of the distal marker, a distal tube covering the outer periphery of the distal marker, and a rearward tube covering the outer periphery of the rearward marker, wherein the rear end of the distal tube and the tip of the rearward tube are spaced apart.

[0008] According to this configuration, since the distal tube and the proximal tube are spaced apart, the flexibility of the catheter distal end can be improved.

[0009] (2) In the catheter of the above embodiment, the shaft includes a straight portion having an outer diameter that is approximately constant in the axial direction of the shaft, and a tapered portion that is provided rearward of the straight portion and has an outer diameter at the rear end that is larger than the outer diameter of the tip, and the tip side marker and the rear side marker may be provided on the straight portion.

[0010] According to this configuration, since the tip end marker and the rear end marker are provided on the straight portion, it becomes easy to visually confirm the position of the part of the catheter inserted into the body that is closer to the tip under X-ray fluoroscopy.

[0011] (3) In the catheter of the above configuration, the rear end tube covers the outer periphery of the tapered portion, and the bending rigidity of the portion of the rear end tube that covers the tip side of the tapered portion may be smaller than the bending rigidity of the portion that covers the rear end side of the tapered portion.

[0012] According to this configuration, the bending rigidity of the portion of the rear end tube closer to the tip end can be reduced, thereby improving the flexibility of the tip end of the catheter.

[0013] (4) The catheter of the above embodiment may further include a distal tip located distal to the distal marker and adjacent to the distal marker.

[0014] According to this configuration, for example, by forming the distal tip from a flexible material, it is possible to improve the flexibility of the leading end of the catheter.

[0015] (5) In the catheter of the above aspect, a portion of the shaft may be disposed between the rear end of the distal tube and the distal end of the rear end tube.

[0016] According to this configuration, since the shaft is disposed between the distal tube and the proximal tube, it becomes easier to pass other medical devices through the inside of the catheter and advance them into the body.

[0017] (6) In the catheter of the above embodiment, the rear end of the distal tube may be located rearward of the rear end of the distal marker, and the distal end of the rear tube may be located distal of the distal end of the rear marker.

[0018] According to this configuration, the distal tube covers the rear end of the distal marker, and the rear tube covers the tip of the rear marker, thereby reducing the possibility of the markers being exposed.

[0019] The present invention can be realized in various aspects, for example, in the form of a guidewire, a method for manufacturing a guidewire, a catheter, a method for manufacturing a catheter, an endoscope, a dilator, and the like. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an explanatory diagram illustrating the overall configuration of a catheter according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating a longitudinal cross section of a catheter tip portion. [Diagram 3] FIG. 13 is an explanatory diagram illustrating a vertical cross section near a marker. [Figure 4] FIG. 2 is an explanatory diagram illustrating a cross section of a catheter. [Diagram 5] 13 is an explanatory diagram illustrating a longitudinal section near a marker of a catheter according to a second embodiment. FIG. [Figure 6] FIG. 11 is an explanatory diagram illustrating a longitudinal section near a marker of a catheter according to a third embodiment. [Figure 7] FIG. 13 is an explanatory diagram illustrating a longitudinal section near a marker of a catheter according to a fourth embodiment. [Figure 8] FIG. 13 is an explanatory diagram illustrating a longitudinal section near a marker of a catheter according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] First Embodiment Fig. 1 is an explanatory diagram illustrating the overall configuration of a catheter 1 of a first embodiment. Fig. 2 is an explanatory diagram illustrating a longitudinal cross section of the tip of the catheter 1. Hereinafter, the end portion of each component of the catheter 1 located on the tip side will be referred to as the "tip", and the portion including the "tip" and extending from the tip to the middle toward the rear end will be referred to as the "tip portion". Similarly, the end portion of each component located on the rear end side will be referred to as the "rear end", and the portion including the "rear end" and extending from the rear end to the middle toward the tip side will be referred to as the "rear portion".

[0022] The catheter 1 is a medical device that is inserted into blood vessels, digestive organs, etc., and is used for treatment, diagnosis, etc. of the human body.

[0023] As shown in Figures 1 and 2, the catheter 1 includes a shaft 15 (Figure 2), an intermediate tube 20, a distal end tube 70, a proximal end tube 90, a distal end marker 30, a proximal end marker 50, a distal tip 110, and a connector 120 (Figure 1).

[0024] As shown in FIG. 2, the shaft 15 is a hollow member extending in the longitudinal direction of the catheter 1. The shaft 15 has a straight portion 16 and a tapered portion 17. The straight portion 16 is a portion of the shaft 15 having a substantially constant outer diameter in the longitudinal direction of the shaft 15. The tapered portion 17 is a portion of the shaft 15 having an outer diameter that increases from the tip side to the rear end side of the shaft 15. The outer diameter of the rear end 17b of the tapered portion 17 is larger than the outer diameter of the tip 17a of the tapered portion 17. In this embodiment, the straight portion 16 is provided on the tip side of the shaft 15, and the tapered portion 17 is provided on the rear end side of the straight portion 16. A lumen 18 is formed inside the shaft 15. The lumen 18 is a space that extends in the longitudinal direction of the shaft 15 by being surrounded by the inner circumference of the shaft 15. A guide wire, a delivery device for carrying an embolic substance used in the treatment of an aneurysm, and the like can be passed through the lumen 18.

[0025] The intermediate tube 20 is a hollow member that covers the outer periphery of the shaft 15. A braid 21 is provided inside the intermediate tube 20 along the longitudinal direction of the catheter 1. The braid 21 is formed by weaving four wires 22 together.

[0026] The distal tube 70 is a hollow member that covers a part of the outer periphery of the intermediate tube 20 and a part of the outer periphery of the distal marker 30. The distal tube 70 is disposed on the outer periphery of the straight portion 16 of the shaft 15.

[0027] The rear end tube 90 is a hollow member that covers a part of the outer periphery of the intermediate tube 20 and the outer periphery of the rear end marker 50. The rear end tube 90 is disposed rearward of the tip end tube 70 in the longitudinal direction of the shaft 15. The rear end tube 90 has a first rear end tube 92 and a second rear end tube 93. The first rear end tube 92 covers the outer periphery on the tip side of the tapered portion 17 of the shaft 15. The second rear end tube 93 covers the outer periphery on the rear side of the tapered portion 17 of the shaft 15. The boundary between the first rear end tube 92 and the second rear end tube 93 is called the "boundary B0."

[0028] The boundary B0 is between the tip 17a and rear end 17b of the tapered portion 17 of the shaft 15, and is located on the tip side of the intermediate position of the tapered portion 17 that is equidistant from the tip 17a and rear end 17b. The bending rigidity of the first rear end tube 92 is smaller than the bending rigidity of the second rear end tube 93. Therefore, the bending rigidity of the rear end tube 90, a portion covering the tip side of the tapered portion 17, is smaller than the bending rigidity of the portion covering the base end side. The bending rigidity of the portion of the rear end tube 90 covering the tip side of the tapered portion 17 and the bending rigidity of the portion covering the base end side are measured as follows. (1) Bending rigidity of the portion covering the tip side of the tapered portion 17 The area of ​​the rear end tube 90 between the tip 17a of the tapered portion 17 and the middle position is divided into four equal parts at equal intervals, and the average value of the bending rigidity of the rear end tube 90 at each of the four equal positions is measured. (2) Bending rigidity of the portion covering the base end side of the tapered portion 17 The area of ​​the rear end tube 90 between the middle position of the tapered portion 17 and the rear end 17b is divided into four equal parts at equal intervals, and the average value of the bending rigidity of the rear end tube 90 at each part is measured. The difference in bending rigidity between the first rear end tube 92 and the second rear end tube 93 can be set, for example, by forming the two tubes from materials with different hardness or by changing the thickness of the two tubes.

[0029] The materials of the shaft 15, the intermediate tube 20, the tip tube 70, and the rear tube 90 are not particularly limited, but examples of materials that can be used include nylon resins such as polyamide, polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers, polyesters such as polyethylene terephthalate, thermoplastic resins such as polyvinyl chloride, ethylene-vinyl acetate copolymers, cross-linked ethylene-vinyl acetate copolymers, and polyurethanes, fluororesins such as polytetrafluoroethylene (PTFE), polyamide elastomers, polyolefin elastomers, polyurethane elastomers, silicone rubber, and latex rubber.

[0030] The distal marker 30 is an annular member formed of a material with low X-ray transmittance. The distal marker 30 is provided at the distal end of the shaft 15. Specifically, the distal marker 30 is disposed on the outer periphery of the straight portion 16 of the shaft 15. "The distal marker 30 is provided at the distal end of the shaft 15" means that at least a part of the distal marker 30 is located at the same axial position as the distal end of the shaft 15, and the distal marker 30 does not necessarily have to be directly connected to the distal end of the shaft 15. Here, the distal marker 30 is indirectly fixed to the distal end of the shaft 15 via the intermediate tube 20. The outer periphery of the distal end of the distal marker 30 is covered by the distal tip 110, and the outer periphery of the rear end of the distal marker 30 is covered by the distal tube 70.

[0031] The rear end marker 50 is an annular member formed of a material with low X-ray transmittance. The rear end marker 50 is provided at the tip of the shaft 15. Specifically, the rear end marker 50 is disposed on the outer periphery of the straight portion 16 of the shaft 15. "The rear end marker 50 is provided at the tip of the shaft 15" means that at least a part of the rear end marker 50 is at the same axial position as the tip of the shaft 15, and the rear end marker 50 does not necessarily have to be directly connected to the tip of the shaft 15. Here, the rear end marker 50 is indirectly fixed to the tip of the shaft 15 via the intermediate tube 20. The rear end marker 50 is provided on the rear end side of the tip marker 30. The outer periphery of the rear end marker 50 is covered by the rear end tube 90.

[0032] The shapes of the front end marker 30 and the rear end marker 50 are not limited to being annular, and may be, for example, plate-shaped covering only a portion of the outer periphery of the intermediate tube 20, or coil-shaped as described in the third embodiment below.

[0033] The material of the distal marker 30 and the proximal marker 50 is not particularly limited, and may be, for example, gold, platinum, tungsten, or an alloy containing these elements (for example, platinum-nickel alloy), etc. Alternatively, the material of the distal marker 30 and the proximal marker 50 may be, for example, a resin material formed by mixing a radiopaque material such as bismuth trioxide, tungsten, barium sulfate, etc. with a polyamide resin, a polyolefin resin, a polyester resin, a polyurethane resin, a silicone resin, a fluororesin, etc.

[0034] The distal tip 110 is a hollow member having a space that communicates with the lumen 18 of the shaft 15. The distal tip 110 is connected to the distal end of the shaft 15, the distal end of the intermediate tube 20, the distal end of the distal tube 70, and the distal end of the distal marker 30. The rear end of the distal tip 110 covers the outer periphery of the distal portion of the distal marker 30.

[0035] The material of the tip 110 is not particularly limited, but for example, resin materials such as polyurethane, polyurethane elastomer, polyamide, and polyamide elastomer can be used.

[0036] The connector 120 is a member connected to the rear end of the rear end tube 90 for connecting the catheter 1 to another medical device such as a syringe (not shown).

[0037] FIG. 3 is an explanatory diagram illustrating a longitudinal cross section of the catheter 1 near the markers (30, 50). As described above, the distal tube 70 covers a portion of the outer periphery of the distal marker 30. The rear end 71 of the distal tube 70 is located further rearward than the rear end 31 of the distal marker 30. As a result, the outer periphery of the distal marker 30 is not exposed to the outside. The rear tube 90 covers the outer periphery of the rear marker 50. The tip 91 of the rear tube 90 is located further forward than the tip 51 of the rear marker 50. As a result, the outer periphery of the rear marker 50 is not exposed to the outside.

[0038] The rear end 71 of the distal tube 70 and the distal end 91 of the rear tube 90 are spaced apart from each other. In the catheter 1, the section between the rear end 71 of the distal tube 70 and the distal end 91 of the rear tube 90 is referred to as "section S0." The space between the rear end 71 of the distal tube 70 and the distal end 91 of the rear tube 90, which is provided in section S0, is referred to as "gap 80." The gap 80 is formed along the outer periphery of the intermediate tube 20. In the catheter 1, the section from the distal end of the distal marker 30 to the rear end 71 of the distal tube 70 is referred to as "section S1." In the catheter 1, the section from the rear end of the rear marker 50 to the distal end 91 of the rear tube 90 is referred to as "section S2."

[0039] Fig. 4 is an explanatory diagram illustrating cross sections of the catheter 1. Fig. 4 (A) to (E) respectively illustrate the AA, BB, CC, DD, and EE cross sections of Fig. 2. Each figure will be explained below. 4(A) is a cross section taken along line AA in FIG. 2, which is a cross section of the distal end of section S1 (FIG. 3). As shown in FIG. 4(A), the outer periphery of the distal marker 30 is covered by the distal tube 70. 4B is a cross section taken along line BB in FIG. 2, which is a cross section of the rear end side of section S1 (FIG. 3). As shown in FIG. 4B, a portion in which the outer periphery of the intermediate tube 20 is covered by the distal tube 70 is provided on the rear end side of the rear end 31 (FIG. 3) of the distal marker 30. 4(C) is a cross section taken along line CC in FIG. 2, which is a cross section of section S0 (FIG. 3). As shown in FIG. 4(C), in section S0 (FIG. 3), the outer periphery of the intermediate tube 20 is exposed and is not covered by the front end tube 70 or the rear end tube 90. In other words, a gap 80 (FIG. 3) is formed along the outer periphery of the intermediate tube 20. 4(D) is a cross section taken along line DD in FIG. 2, which is a cross section of the tip side of section S2 (FIG. 3). As shown in FIG. 4(D), a portion in which the outer periphery of the intermediate tube 20 is covered by the rear end tube 90 is provided on the tip side of the tip 51 (FIG. 3) of the rear end marker 50. 4(E) is an E-E cross section of FIG. 2, which is a cross section of the rear end side of section S2 (FIG. 3). As shown in FIG. 4(E), the outer periphery of the rear end marker 50 is covered by the rear end tube 90.

[0040] The catheter 1 in section S1 is composed of a shaft 15, an intermediate tube 20, a distal tube 70, and a distal marker 30. The catheter 1 in section S2 is composed of a shaft 15, an intermediate tube 20, a proximal tube 90, and a proximal marker 50. The catheter 1 in section S0 does not have the distal tube 70, the proximal tube 90, the distal marker 30, or the proximal marker 50. As a result, the bending rigidity of the catheter 1 in section S0 is smaller than the bending rigidity of the catheter 1 in section S1 and the bending rigidity of the catheter 1 in section S2. In other words, the flexibility of the portion of the catheter 1 between the distal tube 70 and the proximal tube 90 is high. In addition, since the tubes (70, 90) and the markers (30, 50) are not arranged in section S0, the outer diameter of the catheter 1 in section S0 is smaller than the outer diameter of the catheter 1 in section S1 and the outer diameter of the catheter 1 in section S2.

[0041] The braid 21 is formed by a combination of two wires 22 wound in a first direction and two wires 22 wound in a second direction different from the first direction along the longitudinal direction of the intermediate tube 20. The material of the wires 22 is not particularly limited, but for example, tungsten can be used.

[0042] According to the catheter 1 of the first embodiment described above, the rear end 71 of the tip tube 70 and the tip 91 of the rear tube 90 are spaced apart. Since the outer layer tube (70, 90) and the marker (30, 50) are not arranged in the section S0, the bending rigidity of the catheter 1 in the section S0 is smaller than the bending rigidity of the catheter 1 in the section (S1, S2) adjacent to the section S0. Furthermore, the outer diameter of the catheter 1 in the section S0 is smaller than the outer diameter of the catheter 1 in the section (S1, S2). This can improve the flexibility of the tip of the catheter 1. Since the section S0 is located between the tip marker 30 and the rear marker 50, the flexibility of the catheter 1 between the tip marker 30 and the rear marker 50 can be improved.

[0043] The catheter 1 can be used to treat an aneurysm. The distal end marker 30 and the proximal end marker 50 function to display the position of the distal end of the catheter 1 under X-ray fluoroscopy, and can also be used to align a delivery device for carrying an embolic substance used in treating an aneurysm. Specifically, the distal end of the catheter 1 can be confirmed to be located near the treatment site by checking the positions of the markers (30, 50), and the distal end of the delivery device can be positioned at an appropriate position near the treatment site by aligning the positions of the markers (30, 50) with the markers provided at the distal end of the delivery device. The portion of the catheter 1 included in the section S is advanced toward the end of the blood vessel along a guidewire that has been inserted into the blood vessel in advance. It may be difficult for the catheter 1 to advance inside the blood vessel following the guidewire due to resistance from the curved blood vessel, but the flexibility of the portion of the catheter 1 included in the section S makes it easy to follow the guidewire.

[0044] The tip end marker 30 and the rear end marker 50 are provided on the straight portion 16 of the shaft 15. By providing the markers (30, 50) on the straight portion 16 provided on the tip side of the catheter 1, it becomes easy to visually confirm the position of the tip of the catheter 1 inserted into the body under X-ray fluoroscopy.

[0045] Of the rear end tube 90, the bending rigidity of the first rear end tube 92 is smaller than the bending rigidity of the second rear end tube 93. This improves the flexibility of the tip side of the catheter 1. The portion (boundary B0) where the bending rigidity of the rear end tube 90 changes is located between the tip 17a and rear end 17b of the tapered section 17. This suppresses changes in the bending rigidity of the catheter 1 in the straight section 16, making it easier for the straight section 16 to follow the guidewire that has been previously inserted into the body.

[0046] The catheter 1 has a distal tip 110 located distal to the distal marker 30 and adjacent to the distal marker 30. For example, by using a soft material for the distal tip 110, the risk of the catheter 1 damaging the inside of the body can be reduced.

[0047] A part of the shaft 15 is disposed between the rear end 71 of the distal end tube 70 and the distal end 91 of the proximal end tube 90 (section S0). This allows the lumen 18 to be provided even in section S0, making it easy to insert other medical devices into the body through the lumen 18.

[0048] The rear end 71 of the front end tube 70 is located rearward of the rear end 31 of the front end marker 30, and the front end 91 of the rear end tube 90 is located frontward of the front end 51 of the rear end marker 50. As a result, the rear end 31 of the front end marker 30 is covered by the front end tube 70, and the front end 51 of the rear end marker 50 is covered by the rear end tube 90. This reduces the possibility that the markers (30, 50) will be exposed to the outside, and reduces the risk that the markers (30, 50) will come into contact with the inner wall of the body and damage the inner wall of the body.

[0049] <Second embodiment> 5 is an explanatory diagram illustrating a longitudinal section near the markers (30B, 50B) of a catheter 1B of the second embodiment. The catheter 1B differs from the catheter 1 of the first embodiment in that the markers (30B, 50B) are embedded in the intermediate tube 20. A description of the configuration of the catheter 1B that is common to the configuration of the catheter 1 will be omitted.

[0050] The tip marker 30B and the rear end marker 50B are embedded in the tip of the intermediate tube 20. A portion of the outer periphery of the tip marker 30B is covered by the tip tube 70. A portion of the outer periphery of the rear end marker 50B is covered by the rear end tube 90. By embedding the markers (30B, 50B) in the intermediate tube 20, it becomes easy to reduce the outer diameter of the catheter 1B. The catheter 1B can also improve the flexibility of the tip of the catheter 1B.

[0051] <Third embodiment> 6 is an explanatory diagram illustrating a longitudinal section near the markers (30C, 50C) of a catheter 1C of the third embodiment. The catheter 1C differs from the catheter 1 of the first embodiment in that the markers (30C, 50C) are coil-shaped. A description of the configuration of the catheter 1C that is common to the configuration of the catheter 1 will be omitted.

[0052] The tip marker 30C is a coil formed by winding the wire 32C in a spiral shape in the longitudinal direction of the catheter 1C. The rear end marker 50C is a coil formed by winding the wire 52C in a spiral shape in the longitudinal direction of the catheter 1C. The wire (32C, 52C) can be made of a radiopaque material, similar to the markers (30, 50) of the catheter 1 of the first embodiment described above. The tip tube 70 covers the outer periphery of the wire 32C, and the rear end tube 90 covers the outer periphery of the wire 52C. Since the markers (30C, 50C) are coil-shaped, it is possible to suppress an increase in the bending rigidity of the catheter 1C due to the markers (30C, 50C). The catheter 1C can also improve the flexibility of the tip of the catheter 1C.

[0053] <Fourth embodiment> 7 is an explanatory diagram illustrating a longitudinal section near the markers (30, 50) of a catheter 1D of the fourth embodiment. The catheter 1D differs from the catheter 1 of the first embodiment in that a distal tube 70D extends further toward the distal end than the distal end of the shaft 15. Of the configuration of the catheter 1D, a description of the points in common with the configuration of the catheter 1 will be omitted.

[0054] The tip of the tip tube 70D is disposed on the tip side of the tip of the shaft 15, the tip of the intermediate tube 20, and the tip of the tip marker 30 in the longitudinal direction of the catheter 1. The catheter 1D does not have the tip tip 110 of the catheter 1 of the first embodiment, but the tip of the tip tube 70D can have the same function as the tip tip 110. In other words, by using a flexible material for the tip tube 70D, the risk of the catheter 1 damaging the inside of the body can be reduced. In addition, there is no risk of the tip tip 110 and the tip tube 70D breaking at the connection part between the tip tip 110 and the tip tube 70D, so the durability of the catheter 1 can be improved. The catheter 1D can also improve the flexibility of the tip of the catheter 1D.

[0055] <Fifth embodiment> 8 is an explanatory diagram illustrating a vertical cross section near the markers (30, 50) of a catheter 1E of the fifth embodiment. The catheter 1E is different from the catheter 1 of the first embodiment in that the rear end 71E of the tip tube 70E and the tip 91E of the rear end tube 90E (first rear end tube 92E) have a tapered shape. A description of the configuration of the catheter 1E that is common to the configuration of the catheter 1 will be omitted.

[0056] In this embodiment, the thickness of the tip tube 70E is called "thickness t1" and the thickness of the rear tube 90E is called "thickness t2". The rear end 71E of the tip tube 70E has a tapered shape in which the thickness t1 gradually decreases from the tip side to the rear end side of the catheter 1E. The tip 91E of the rear tube 90E has a tapered shape in which the thickness t2 gradually decreases from the rear end side to the tip side of the catheter 1E. In addition, the rear end 71E of the tip tube 70E and the tip 91E of the rear tube 90E have a curved outer surface. This makes it possible to make the change in bending rigidity in the longitudinal direction of the catheter 1E gentle in the vicinity of the rear end 71E of the tip tube 70E and the vicinity of the tip 91E of the rear tube 90E. The catheter 1E can also improve the flexibility of the tip of the catheter 1E.

[0057] <Modification> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0058] <Variation 1> In the catheters (1, 1B, 1C, 1D, 1E) of the first to fifth embodiments, the tip markers (30, 30B, 30C) and the rear end markers (50, 50B, 50C) are provided on the straight portion 16 of the shaft 15. However, the tip markers (30, 30B, 30C) and the rear end markers (50, 50B, 50C) may be provided on the tapered portion 17 of the shaft 15.

[0059] <Variation 2> The catheters (1, 1B, 1C, 1D, 1E) of the first to fifth embodiments are configured by overlapping a shaft 15, an intermediate tube 20, a tip tube (70, 70D, 70E), and a rear end tube (90, 90E). However, the catheters (1, 1B, 1C, 1D, 1E) may not have the shaft 15, and may not have the intermediate tube 20. For example, the catheters (1, 1B, 1C, 1D, 1E) may be configured by a tip tube (70, 70D, 70E) covering the outer periphery of the tip marker (30, 30B, 30C) and a rear end tube (90, 90E) covering the outer periphery of the rear end marker (50, 50B, 50C).

[0060] <Modification 3> In the catheters (1, 1B, 1C, 1D, 1E) of the first to fifth embodiments, the rear end (71, 71E) of the distal tube (70, 70D, 70E) is located rearward of the rear end 31 of the distal marker (30, 30B, 30C), and the front end (91, 91E) of the rear tube (90, 90E) is located distal of the front end 51 of the rear marker (50, 50B, 50C). However, the rear end (71, 71E) of the distal tube (70, 70D, 70E) may be located distal of the rear end 31 of the distal marker (30, 30B, 30C), and the front end (91, 91E) of the rear tube (90, 90E) may be located rearward of the front end 51 of the rear marker (50, 50B, 50C). [Explanation of symbols]

[0061] 1. Catheter 15…Shaft 16…Straight section 17…Tapered section 18…lumens 20…Intermediate tube 21...Braid 22…Wire 30…Tip marker 31…Rear end of leading edge marker 50…Rear end marker 51…Tip of rear marker 70…Tip side tube 71…Rear end of distal tube 90…Rear end tube 91…Tip of rear tube 110…Tip 120…Connector S0: Section between the front tube and rear tube S1: Section from the tip of the distal marker to the rear end of the distal tube S2: Section from the rear end of the rear end marker to the tip of the rear end tube

Claims

1. A catheter comprising: A hollow shaft; a distal end marker provided at a distal end portion of the shaft; a rear end marker provided at a tip portion of the shaft and positioned rearward of the tip end marker; a distal tube covering the outer periphery of the distal marker; a rear end tube covering an outer periphery of the rear end marker, A catheter in which the rear end of the distal tube and the distal end of the proximal tube are spaced apart from each other.

2. 10. The catheter of claim 1, The shaft has a straight portion having a substantially constant outer diameter in an axial direction of the shaft; a tapered portion provided on the rear end side of the straight portion and having an outer diameter at the rear end larger than an outer diameter at the front end, A catheter, wherein the distal end marker and the proximal end marker are provided on the straight portion.

3. The catheter according to claim 1 or 2, the rear end tube covers the outer periphery of the tapered portion, A catheter, wherein the bending rigidity of the portion of the rear end tube that covers the tip side of the tapered portion is smaller than the bending rigidity of the portion that covers the rear end side of the tapered portion.

4. The catheter according to claim 1 or claim 2 further comprises: A catheter comprising a distal tip located distal to and adjacent to the distal marker.

5. The catheter according to claim 1 or claim 2 comprises: A catheter, wherein a portion of the shaft is disposed between the rear end of the distal tube and the distal end of the rear tube.

6. The catheter according to claim 1 or 2, the rear end of the distal tube is located rearward of the rear end of the distal marker, A catheter, wherein the tip of the rear end tube is located further forward than the tip of the rear end marker.

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