conduit

Abstract

A catheter suitable for passing through a hard site is provided. In the catheter 1, a shaft 10 having a hollow shape, and a metal front-end tip 30 connected to a front end of the shaft 10, the front-end tip 30 having a diameter-increased portion 33 between a front end of the front-end tip 30 and a front end of the shaft 10, the diameter-increased portion 33 having a maximum outer diameter in a direction perpendicular to an axial direction of the shaft 10, the outer diameter (DT1) of the diameter-increased portion 33 being larger than an outer diameter (DS) of the front end of the shaft 10. The outer shape between the front end side and the base end side of the front-end tip sandwiching the diameter-increased portion can also be formed by a curved surface whose inclination gradually changes. In addition, the outer shape of the front-end tip between the diameter-increased portion and the front end of the shaft 10 can also be formed to be concave toward the outside.

Description

TECHNICAL FIELD

[0001] The present application relates to a catheter. BACKGROUND

[0002] For example, a catheter that improves blood flow by removing an occlusion such as a chronic total occlusion (CTO) that blocks a blood vessel is known.

[0003] In such a catheter, a catheter provided with a metal tip at a front end to pass through a hard lesion site is known (see, for example, Patent Literature 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2018-519957 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] With a catheter that passes through a hard lesion site, it is required that the catheter easily passes through the lesion site and that the lesion site does not damage the catheter when passing through the lesion site.

[0009] The present application has been achieved in view of the above requirements, and an object thereof is to provide a catheter suitable for passing through a hard site.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] To achieve the above object, a catheter according to one aspect includes a hollow shaft, and a metal tip connected to a front end of the shaft, the metal tip having a diameter-increasing portion between a front end of the metal tip and the front end of the shaft, the diameter-increasing portion having a maximum outer diameter in a direction perpendicular to an axial direction of the shaft, the outer diameter of the diameter-increasing portion being larger than an outer diameter of the front end of the shaft.

[0012] In the above catheter, the outer shape of the metal tip between the front end side and the base end side sandwiching the diameter-increasing portion can be formed by a curved surface whose inclination gradually changes. In the above catheter, the outer shape of the metal tip between the diameter-increasing portion and the front end of the shaft can be formed to be concave toward the outside. In the above catheter, a slit can be formed in an outer peripheral surface of the metal tip closer to the front end side than the diameter-increasing portion. In the above catheter, a protruding portion can be formed in the outer peripheral surface of the metal tip, the protruding portion extending in a spiral shape and protruding toward the radial outside.

[0013] EFFECTS OF THE INVENTION

[0014] According to the present application, a catheter suitable for passing through a hard site can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural view of a catheter according to a first embodiment.

[0016] Figure 2 is a structural view of a catheter according to a second embodiment. Figure 1 is a structural view of a catheter according to a third embodiment.

[0017] Figure 3 is a structural view of a catheter according to a fourth embodiment.

[0018] Figure 4 is a structural view of a catheter according to a fifth embodiment.

[0019] Figure 5 is a structural view of a catheter according to a sixth embodiment.

[0020] Figure 6 is a structural view of a catheter according to a seventh embodiment. DETAILED DESCRIPTION

[0021] A catheter according to some embodiments will be described with reference to the accompanying drawings, but the present application is not limited to the embodiments described in the accompanying drawings.

[0022] In the present specification, "distal side" and "distal direction" are directions extending along the length direction of the catheter (directions along the axial direction of the hollow shaft), and mean the side and direction on which the distal tip is located with respect to the hollow shaft. In addition, "proximal side" and "proximal direction" are the side and direction extending along the length direction of the catheter, and mean the side and direction opposite to the distal side and the distal direction. In addition, "distal end" indicates the end portion of the distal side of an arbitrary member or site, and "proximal end" indicates the end portion of the proximal side of an arbitrary member or site.

[0023] [First Embodiment]

[0024] Figure 1 is a structural view of a catheter according to a first embodiment. The catheter 1 includes a shaft 10, a connector 20 provided on the proximal side of the shaft 10, and a distal tip 30 connected to the distal side of the shaft 10.

[0025] Figure 2 is a structural view of the vicinity of the distal end of the catheter shown in Figure 1 is a structural view of the vicinity of the distal end of the catheter shown in

[0026] The coil body 11 is an example of a reinforcing body that reinforces the shaft 10, and is formed by spirally winding a wire of metal. The coil body 11 can be a coil body formed by spirally winding one wire (single wire coil), or a coil body formed by spirally winding a plurality of wires (stranded wire coil). If the rotational force of the catheter 1 is considered, it is preferable that the coil body 11 be a stranded wire coil. The metal material of the wire of the coil body 11 can be stainless steel (SUS304, SUS316, etc.), gold, silver, tungsten, platinum, nickel, and alloys containing these elements, etc.

[0027] The outer layer 12 is, for example, a layer formed of a resin, and is provided so as to cover the outer periphery of the coil body 11. The resin material that forms the outer layer 12 is not particularly limited, and can be, for example, polyamide, polyamide elastomer, polyester, polyurethane, etc.

[0028] The inner layer 13 is, for example, a layer formed of a resin, and is provided so as to cover the inner periphery of the coil body 11. The resin material that forms the inner layer 13 is not particularly limited, and if the slidability with an instrument (guide wire, etc.) inserted into the inside of the shaft 10 is considered, it is preferable that PTFE (polytetrafluoroethylene) be used.

[0029] A front end tip 30 of a hollow shape made of metal is connected to the front end portion 14 of the shaft 10. The front end tip 30 includes a main body portion 31 and a covering layer 32.

[0030] The main body portion 31 is composed of a metal material. The metal material that composes the main body portion 31 is not particularly limited, and can be, for example, stainless steel (SUS304, SUS316, etc.), gold, silver, tungsten, platinum, nickel, and alloys containing these elements, etc. In addition, in order to be able to grasp the position of the front end of the catheter 1 under a radioscopic image, the front end tip 30 can also be formed of a metal material that is radiopaque.

[0031] The covering layer 32 is, for example, a layer formed of a resin, and is provided so as to cover the outer periphery of the main body portion 31. The resin material that forms the covering layer 32 is not particularly limited, and can be, for example, polyamide, polyamide elastomer, polyester, polyurethane, etc.

[0032] The front end tip 30 has a diameter expansion portion 33 between the front end thereof and the front end portion 14 of the shaft 10, and the outer diameter of the diameter expansion portion 33 is the largest in a direction perpendicular to the axial direction (length direction) of the shaft 10. The outer diameter DT1 of the diameter expansion portion 33 is larger than the outer diameter DS of the front end portion 14 of the shaft 10. In addition, the outer diameter of the main body portion 31 itself at the diameter expansion portion 33 is also larger than the outer diameter DS of the front end portion 14 of the shaft 10.

[0033] The front tip 30 is formed in a tapered shape in which the outer diameter decreases from the enlarged diameter portion 33 toward the front end, and in a tapered shape in which the outer diameter decreases from the enlarged diameter portion 33 toward the front end portion 14 of the shaft 10. The outer diameter of the rear end of the front tip 30 is the same as the outer diameter DS, and the outer periphery of the rear end is continuous with the outer periphery of the front end portion 14 of the shaft 10. The shaft 10 is connected to the front tip 30 in a manner in which the outer peripheries are continuous.

[0034] The front tip 30 and the shaft 10 are formed in a manner in which the rear end surface of the front tip 30 and the front end surface of the shaft 10 are in contact with at least a portion of each of the surfaces. The front tip 30 and the shaft 10 are joined at the rear end surface of the front tip 30 and the front end surface of the shaft 10. As shown in Figure 2 The coil 11 and the main body portion 31 can be joined at the surfaces in contact with each other by welding. Also, the covering layer 32 and the outer layer 12 can be joined at the portions in contact with each other by heat fusion.

[0035] In a case in which the catheter 1 is advanced toward a hard lesion (for example, a calcified lesion), the shaft 10 will pass through the portion of the front tip 30 that passes through the enlarged diameter portion 33. In the catheter 1, since the outer diameter of the front end portion 14 of the shaft 10 is smaller than the outer diameter of the enlarged diameter portion 33, the contact area of the lesion with the shaft 10 is reduced. The reduction in the contact area can appropriately reduce the shaft 10 from being caught in the lesion, and the shaft 10 from being damaged by the lesion. Also, the reduction in the contact area can reduce the contact resistance generated by the shaft 10 when the catheter 1 is advanced, and can improve the propulsion force (propulsion performance) of the catheter 1.

[0036] [Second Embodiment]

[0037] Figure 3 is a structural view of the vicinity of the front end of the catheter according to the second embodiment, and shows a cross section of the catheter front end as shown in Figure 2 The catheter 1A according to the second embodiment differs from the catheter 1 in the shape of the front tip. For portions that are the same as those of the above-described embodiment, the same reference numerals are assigned, and repeated descriptions are omitted. The front tip 40 according to the second embodiment includes a main body portion 41 and a covering layer 42. The main body portion 41 and the covering layer 42 are the same as the main body portion 31 and the covering layer 32 except for the shape.

[0038] The front tip 40 has an enlarged diameter portion 43 having the largest outer diameter between the front end of the front tip and the front end portion 14 of the shaft 10. The outer diameter DT2 of the enlarged diameter portion 43 is larger than the outer diameter DS of the front end portion 14 of the shaft 10. Also, the outer diameter of the main body portion 41 itself at the enlarged diameter portion 43 is larger than the outer diameter DS of the front end portion 14 of the shaft 10. The front tip 40 has an outer peripheral surface 44 that reaches the front end portion 14 of the shaft 10 from a position closer to the front end side than the enlarged diameter portion 43 via the enlarged diameter portion 43. As shown in Figure 3As shown, the outer peripheral surface 44 is formed by a curved surface that is convex to the outer side and whose inclination gradually changes in the longitudinal section of the catheter 1A, that is, by a gently curved surface. The inclination means the amount of change in the outer peripheral surface 44 in the radial direction of the catheter 1A with respect to the axial length of the catheter 1A in the longitudinal section.

[0039] According to the catheter 1A related to the present embodiment, in addition to the effects of the first embodiment, in the case where the catheter 1A is advanced toward the distal end side, it is possible to appropriately prevent damage to a normal blood vessel that comes into contact with the outer peripheral surface closer to the base end side than the enlarged diameter portion 43 of the distal tip 40 and / or the enlarged diameter portion 43.

[0040] [Third Embodiment]

[0041] Figure 4 is a structural view of the vicinity of the distal end of the catheter related to the third embodiment, and a cross section of the distal end of the catheter is shown as shown in Figure 2 The catheter 1B related to the third embodiment differs from the catheter 1 in the shape of the distal tip. For the same parts as those of the above-described embodiments, the same reference numerals are assigned and repeated explanations are omitted. The distal tip 50 related to the third embodiment includes a main body portion 51 and a coating layer 52. The main body portion 51 and the coating layer 52 are the same as the main body portion 31 and the coating layer 32 except for the shape.

[0042] The distal tip 50 has an enlarged diameter portion 53 having the largest outer diameter between the distal end thereof and the distal end portion 14 of the shaft 10. The outer diameter DT3 of the enlarged diameter portion 53 is larger than the outer diameter DS of the distal end portion 14 of the shaft 10. In addition, the outer diameter of the main body portion 51 itself at the enlarged diameter portion 53 is also larger than the outer diameter DS of the distal end portion 14 of the shaft 10. The outer peripheral surface 54 of the distal tip 50 closer to the distal end portion 14 of the shaft 10 than the enlarged diameter portion 53 is formed by a curved surface that is concave to the outer side.

[0043] In the case where the catheter 1B is advanced toward a hard lesion (for example, a calcified lesion), in the portion through which the enlarged diameter portion 53 of the distal tip 50 passes, it is possible to more effectively reduce the contact of the outer peripheral surface 54 closer to the base end side than the enlarged diameter portion 53 with the lesion. Thus, it is possible to appropriately reduce the case where the outer peripheral surface 54 is caught in the lesion. In addition, since the enlarged diameter portion 53 of the distal tip 50 can reduce the contact with the lesion, it is possible to reduce the contact resistance at the time of advancement of the catheter 1B and to improve the propulsive force (propulsive performance) of the catheter 1B. In addition, in the case where the catheter 1B is advanced toward the distal end side, it is possible to reduce the contact of the outer peripheral surface 54 of the distal tip 50 with a normal blood vessel and to appropriately prevent damage to the blood vessel.

[0044] [Fourth Embodiment]

[0045] Figure 5is a structural view of a tip of a catheter according to the fourth embodiment, (A) is a cross-sectional view of the tip, and (B) is a side view of the tip. The tip 60 according to the fourth embodiment is formed with a slit 64, in contrast to the tip 30 according to the first embodiment. The tip 60 includes a main body portion 61 and a coating layer 62. The main body portion 61 is the same as the main body portion 31 except that the slit 64 is formed therein. The coating layer 62 is the same as the coating layer 32 except that the resin thereof enters the slit 64.

[0046] In the main body portion 61, as shown in (B) of Figure 5 , the slit 64 is formed in a spiral shape. The slit 64 is provided to increase the flexibility of the main body portion 61 by thinning the same. In the present embodiment, since the slit 64 is formed in a spiral shape, the tip 60 can be bent in any direction with the same ease of bending. In addition, the pitch of the slit 64 is formed to be smaller toward the tip end, and the tip end region of the tip 60 becomes particularly flexible. Thus, the risk of perforating a blood vessel by the tip 60 can be reduced.

[0047] In the tip 60, as shown in (A) of Figure 5 , the resin of the coating layer 62 is configured to enter the inside of the slit 64 of the main body portion 61.

[0048] Since the tip 60 is provided with the slit 64, the tip 60 can be easily bent while maintaining the rigidity thereof. In addition, since the outer peripheral surface of the tip 60 is covered by the coating layer 62, the surface of the tip 60 can be smoothed. As a result, the catheter provided with the tip 60 can be easily passed through a hard lesion portion, and also exhibits good followability in a tortuous blood vessel such as a distal blood vessel.

[0049] In addition, in the tip 60, since the resin of the coating layer 62 enters the inside of the slit 64, the coating layer 62 can be firmly fixed to the main body portion 61. Thus, peeling of the coating layer 62 from the main body portion 61 due to friction with the outside can be appropriately prevented. Thus, in the case where the tip 60 is passed through a hard lesion portion, the smoothness of the outer peripheral surface of the tip 60 can be maintained.

[0050] [Fifth Embodiment]

[0051] Figure 6 is a structural view of a tip of a catheter according to the fifth embodiment, (A) is a side view of the tip, and (B) is a side view of a modified example of the tip formed by deforming the configuration shown in (A).

[0052] The tip 70 includes a main body 71. The main body 71 is identical to the main body 31 except for its shape. The tip 70 has an enlarged diameter portion 72 with the largest outer diameter between its tip and the front end portion 14 of the shaft 10. The enlarged diameter portion 72 has a predetermined width in the axial direction of the shaft 10. The outer diameter of the enlarged diameter portion 72 is larger than the outer diameter DS of the front end portion 14 of the shaft 10. A protrusion 73 is provided on the surface (outer peripheral surface) of the main body 71 of the tip 70. This protrusion 73 extends spirally and protrudes radially outward from the main body 71. The protrusion 73 is only provided within the area of ​​the enlarged diameter portion 72. According to this tip 70, the protrusion 73 improves penetration into hard lesion sites.

[0053] Alternatively, the front end can be set to Figure 6 The front end tip 80 is shown in (B). The front end tip 80 includes a main body 81. The main body 81 is the same as the main body 31 except for its shape. The front end tip 80 has an enlarged diameter portion 82 with the largest outer diameter between its front end and the front end portion 14 of the shaft 10. The enlarged diameter portion 82 has a predetermined width in the axial direction of the shaft 10. The outer diameter of the enlarged diameter portion 82 is larger than the outer diameter DS of the front end portion 14 of the shaft 10. A protrusion 83 is provided on the surface of the main body portion 81 of the front end tip 80. The protrusion 83 extends in a spiral shape and protrudes radially outward from the main body portion 81. The protrusion 83 is provided from a position closer to the front end than the enlarged diameter portion 82 to the rear end of the enlarged diameter portion 82. According to this front end tip 80, since the protrusion 83 is provided from a position closer to the front end than the enlarged diameter portion 82, the penetration of hard lesions can be further improved.

[0054] The technology disclosed in this specification is not limited to the above-described embodiments and variations, and can be modified in various ways without departing from its spirit, for example, the following modifications are also possible.

[0055] In the above embodiment, the shaft 10 has a coil body 11 as an example of its reinforcement, but the invention is not limited to this method, and the reinforcement may also be, for example, a braided layer. When a braided layer is used as the reinforcement, the braided layer may also be joined to the front end tips 30, 40, 50 by welding.

[0056] For example, in the fourth embodiment, a slit is provided relative to the tip 30 of the first embodiment. Furthermore, in the fifth embodiment, a protrusion is provided relative to the tip 30 of the first embodiment. However, the present invention is not limited thereto; for example, both slits and protrusions may be formed on the tip 40 and 50.

[0057] Furthermore, the present invention is not limited to the structure of the above-described embodiments, but rather includes all modifications within the meaning and scope equivalent to the claims, as shown in the claims.

[0058] Reference Signs

[0059] 1, 1A, 1B catheter

[0060] 10 shaft

[0061] 11 coil body (reinforcing body)

[0062] 12 outer layer

[0063] 13 inner layer

[0064] 14 front end portion

[0065] 20 connector

[0066] 30, 40, 50, 60, 70, 80 front end tip

[0067] 31, 41, 51, 61, 71, 81 body portion

[0068] 32, 42, 52, 62 covering layer

[0069] 33, 43, 53, 63, 72, 82 enlarged diameter portion

[0070] 44, 54 outer peripheral surface

[0071] 64 slit

[0072] 73, 83 protrusion

[0073] R region

[0074] DT1, DT2, DT3, DT4 outer diameter of enlarged diameter portion

[0075] DS outer diameter of front end portion

Claims

1. A catheter, said catheter comprising: Hollow shaft; as well as A metal tip, which is connected to the front end of the shaft, wherein... The tip has an enlarged diameter portion between its tip and the tip of the shaft, and the outer diameter of the enlarged diameter portion is largest in the direction perpendicular to the axial direction of the shaft. The outer diameter of the expanded section is larger than the outer diameter of the front end of the shaft. The front end of the tip, from the expanded diameter portion to the front end of the shaft, is concave outward.

2. The catheter according to claim 1, wherein, The tip has a shape that sandwiches the front end side and the base end side of the enlarged portion, and the shape is formed by a curved surface with a gradually changing inclination in the longitudinal section of the conduit.

3. The catheter according to claim 1 or 2, wherein, A slit is formed on the outer peripheral surface of the tip that is closer to the front end than the expanded diameter portion.

4. The catheter according to claim 1 or 2, wherein, A protrusion is formed on the outer peripheral surface of the tip, the protrusion extending in a spiral shape and protruding radially outward.

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