Catheter

Abstract

To provide a catheter excellent in operability capable of suppressing excessive deflection of a part on a base end side while maintaining passing performance into a lesion in a predetermined range on a tip side of the catheter.SOLUTION: A catheter includes: a shaft 10 having a lumen 11 which communicates in the axial direction from the tip to the base end; an operation part 20 fixed to the base end of the shaft 10; and a reinforcement tube 30, which is a tube body covering the circumference of the shaft 10 that is slidable in the axial direction with respect to the shaft 10, and which is provided with a connection part 33 connected to the operation part 20 at the base end. The maximum outer diameter D3 of the connection part 33 is smaller than the maximum outer diameter D4 of the operation part 20, and in the state that the connection part 33 is connected to the operation part 20, the tip of the reinforcement tube 30 is arranged at the position of 200-600 mm from the tip of the shaft 10 to the base end side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a catheter for use in a lumen such as a blood vessel. [Background technology]

[0002] In recent years, intraluminal treatments such as those using catheters for blood vessels have become popular because of the minimal surgical invasiveness involved. Catheters are selectively introduced into the complexly branched blood vessels within the body, and their internal lumens can supply therapeutic drugs, diagnostic contrast agents, and the like into the body, or guide other therapeutic catheters to the desired location (see, for example, Patent Document 1). When treating peripheral blood vessels or complex lesions with a catheter, it is necessary to reduce the outer diameter of the catheter in order to improve its reachability to the target blood vessel and its passability to the lesion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-230710 Summary of the Invention [Problem to be solved by the invention]

[0004] The inner diameter of a blood vessel, for example, is approximately 10 mm in the common iliac artery, but is approximately 3-4 mm in the more peripheral arteries below the knee, becoming smaller as the vessel becomes more distal. To reach lesions in the peripheral region, a thin catheter corresponding to the peripheral lesion must be used, but thin catheters tend to bend excessively in blood vessels with a large inner diameter. Therefore, if a catheter thinner than appropriate for the inner diameter of the blood vessel is inserted, the backup performance of the guidewire inserted into the catheter to support the catheter and the pushability of the catheter itself are reduced.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a catheter that can suppress excessive bending at the base end while maintaining passability to a lesion within a predetermined range at the tip end of the catheter, and that is easy to operate. [Means for solving the problem]

[0006] The catheter of the present invention, which achieves the above-mentioned object, comprises a shaft having a lumen that passes through in the axial direction from the tip to the base end, an operating section fixed to the base end of the shaft, and a reinforcing tube that covers the periphery of the shaft and is a tubular body that is slidable in the axial direction relative to the shaft and has a connecting section at its base end that can be connected to the operating section, wherein the maximum outer diameter of the connecting section is smaller than the maximum outer diameter of the operating section, and when the connecting section is connected to the operating section, the tip of the reinforcing tube is located at a position that is 200 mm to 600 mm from the tip of the shaft toward the base end. [Effects of the Invention]

[0007] The catheter configured as described above can suppress excessive bending within a blood vessel by the portion of the shaft where the outside of the shaft is covered with the reinforcing tube, while maintaining passability to lesions in a predetermined area of ​​the shaft near the distal end that is not covered by the reinforcing tube, which extends 200 mm to 600 mm from the distal end of the shaft toward the proximal end, while suppressing excessive bending in the proximal portion. Furthermore, because the connecting portion of the reinforcing tube can be connected to a control section fixed to the proximal end of the shaft, and the maximum outer diameter of the connecting portion is smaller than the maximum outer diameter of the control section, the connecting portion of the reinforcing tube is unlikely to interfere with the operator's operation of the control section, and the reinforcing tube can be slid relative to the shaft to move away from the control section as needed. This provides excellent operability for the catheter.

[0008] The operating section may have a ring-shaped connecting recess recessed from the distal end toward the proximal end, and the connecting section may fit into the connecting recess and be connectable to the operating section. This allows the connecting section of the reinforcing tube to be surrounded by the distal end of the operating section, making it less likely that the connecting section of the reinforcing tube will interfere with the operation of the operating section by the surgeon, and facilitating the operation of the shaft and the reinforcing tube fixed to the operating section as a single unit. Furthermore, the reinforcing tube can be slid toward the distal end relative to the shaft, as needed, to move away from the operating section.

[0009] The connecting part may be connectable to the operating part by covering the outer surface of the distal end side of the operating part. This makes it easy to operate the connecting part of the reinforcing tube and the operating part of the catheter as a single unit. In addition, the connecting part of the reinforcing tube can be easily detached from the operating part, and the reinforcing tube can be easily slid toward the distal end relative to the shaft to move away from the operating part as needed.

[0010] The reinforcing tube may have a plurality of protrusions on its inner surface, which form a gap between the shaft and the reinforcing tube, making it easier for the sterilizing gas to reach between the shaft and the reinforcing tube. This also reduces the contact area between the reinforcing tube and the shaft, improving the sliding properties of the reinforcing tube relative to the shaft.

[0011] The reinforcing tube may have a breakable weakened portion extending from the distal end to the proximal end, which allows the catheter to be removed from the shaft by breaking the weakened portion located outside the body while the distal end of the shaft is inserted into a blood vessel.

[0012] The reinforcing tube may have a thick-walled portion at its distal end that is thicker than its proximal end. This allows the thick-walled portion and the shaft covered by the thick-walled portion to form a locally less flexible portion at the proximal end of the portion that is inserted into the lesion, making it possible to adjust the engagement with the blood vessel, pushability, etc. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view showing a catheter according to an embodiment. [Figure 2] FIG. 1 is an enlarged cross-sectional view taken along the axis of a catheter according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 1 is a cross-sectional view perpendicular to the axis of a first modified example of the catheter. [Figure 5] FIG. 10 is a cross-sectional view taken along the axis of a second modified example of the catheter. [Figure 6] FIG. 10 is a plan view showing a third modified example of the catheter. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For convenience of explanation, the dimensions in the drawings may be exaggerated and may differ from the actual dimensions. Furthermore, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted. In this specification, the side of a catheter that is inserted into a biological lumen will be referred to as the "distal side," and the side that is operated will be referred to as the "proximal side."

[0015] The catheter 1 according to this embodiment is introduced into a blood vessel, for example, from the radial artery in the arm and inserted into an artery in the lower limb, and is used for treatment, diagnosis, etc. The artery in the lower limb refers to an artery near the aortoiliac artery bifurcation and a more peripheral artery. The catheter 1 may be inserted from a blood vessel other than an artery in the arm. The catheter 1 may also be used for treatment or diagnosis of blood vessels other than arteries in the lower limb. The catheter 1 may also be inserted into the bile duct, trachea, esophagus, urethra, or other body lumen or body cavity, and used for treatment, diagnosis, etc.

[0016] As shown in FIG. 1, the catheter 1 has a long shaft 10, an operation section 20 fixed to the base end of the shaft 10, and a tubular reinforcing tube 30 that covers the shaft 10.

[0017] 1 to 3, the shaft 10 is a flexible tubular member, and has a lumen 11 formed therein from the base end to the tip. A guidewire is inserted through the lumen 11 when the catheter 1 is inserted into a blood vessel. The lumen 11 can also be used as a passage for a medicinal solution, an embolic substance, a contrast agent, a medical instrument, etc. That's fine too.

[0018] The shaft 10 is composed of multiple layers, including an inner layer 12 that forms the inner surface of the lumen 11, a reinforcing body 13 formed on the outside of the inner layer 12, and an outer layer 14 formed on the outside of the inner layer 12 and the reinforcing body 13.

[0019] The inner layer 12 has a lumen 11 formed therein. The material constituting the inner layer 12 is preferably a low-friction material such as a fluorine-based resin such as polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE). Alternatively, the inner layer 12 may be a material mixed with a powder of a metal such as tungsten that has X-ray contrast, such as polyamide resin, polyamide elastomer, polyester, or polyester elastomer.

[0020] The reinforcing member 13 is formed by braiding a plurality of wires 15 into a tubular shape with gaps between them around the outer periphery of the inner layer 12. The wires 15 used in the reinforcing member 13 can be metal wires such as stainless steel, platinum (Pt), tungsten (W), etc., resin fiber, carbon fiber, glass fiber, etc.

[0021] The outer layer 14 is a tubular member that covers the outer periphery of the inner layer 12 and the reinforcing member 13. Examples of materials that can be used for the outer layer 14 include polymeric materials such as polyolefin (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof), polyvinyl chloride, polyamide, polyester elastomer, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, and fluororesin, as well as thermoplastic resins such as mixtures of these, and thermosetting resins such as epoxy resin. Alternatively, the outer layer 14 may be made of a material containing a mixture of polyamide resin, polyamide elastomer, polyester, polyester elastomer, or even a metal powder having X-ray contrast properties, such as tungsten, or the same material as the inner layer 12.

[0022] The shaft 10 also has a shaft main portion 16 with a substantially constant outer diameter, and a shaft tip portion 17 that is located on the tip side of the shaft main portion 16 and has an outer diameter that decreases toward the tip. The base end of the shaft main portion 16 is fixed to a hub 21 of the operating unit 20, which will be described later.

[0023] The outer diameter D1 of the shaft main portion 16 is not particularly limited, but is, for example, 0.70 mm or more and 0.85 mm or less.

[0024] The operating section 20 has a hub 21 and a kink-resistant protector 22. The maximum outer diameter D4 of the operating section 20 in FIG. 1 is the wing portion of the hub 21, but if the kink-resistant protector 22 is gripped and operated, the maximum outer diameter D4 of the operating section 20 may be the maximum outer diameter of the kink-resistant protector 22. Furthermore, the operating section 20 may be one in which the hub 21 and the kink-resistant protector are integrated. The hub 21 is liquid-tightly fixed to the proximal end of the shaft main section 16 by adhesive, heat fusion, a fastener (not shown), or the like. The hub 21 functions as an insertion port for a guidewire or a medical instrument into the lumen 11, an injection port for a medicinal solution, an embolic substance, a contrast agent, etc. into the lumen 11, and also functions as a gripping portion when operating the catheter 1. The material of which the hub 21 is made is not particularly limited, but for example, thermoplastic resins such as polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate-butylene-styrene copolymer can be suitably used.

[0025] Anti-kink protector 22 is made of an elastic material and is provided so as to surround the periphery of shaft 10, and suppresses kinking of shaft 10 at connecting portion 33 between shaft 10 and hub 21. Anti-kink protector 22 has a tubular connecting protrusion 23 that protrudes toward the tip side so as to form a gap with the outer circumferential surface of shaft 10, and a ring-shaped connecting recess 24 that is recessed from the tip side toward the base end side is formed so as to be surrounded by connecting protrusion 23. Suitable materials for anti-kink protector 22 include, for example, natural rubber and silicone resin.

[0026] The reinforcing tube 30 is a tubular body for reinforcing the shaft 10. The reinforcing tube 30 covers the periphery of the shaft 10 and is slidable relative to the shaft 10 in the axial direction X of the shaft 10. The reinforcing tube 30 has a tapered portion 31 whose outer diameter decreases toward the tip, a reinforcing tube main portion 32 whose inner and outer diameters are substantially constant, and a connecting portion 33 that can be fitted into and connected to the connecting recess 24 of the operating portion 20. The outer diameter D2 of the reinforcing tube main portion 32 is not particularly limited as long as it is larger than the outer diameter D1 of the shaft main portion 16, but is, for example, 0.85 mm or more and 1.5 mm or less. When the outer diameter D1 of the shaft main portion 16 is 0.85 mm, the outer diameter D2 of the shaft main portion 16 is preferably 0.95 mm or more and 1.5 mm or less.

[0027] The reinforcing tube 30 is formed with a breakable weakened portion 34 extending from the distal end to the proximal end. The weakened portion 34 is a portion that is weaker in strength than the surrounding portions and is more easily broken. The weakened portion 34 is formed, for example, by a perforation or groove consisting of a plurality of holes lined up. Note that the reinforcing tube 30 does not necessarily have to have the weakened portion 34.

[0028] The connecting portion 33 is a tubular body continuing from the main reinforcing pipe. The maximum outer diameter D3 of the connecting portion 33 is smaller than the maximum outer diameter D4 of the operating portion 20 to be connected. The maximum outer diameter D3 of the connecting portion 33 is twice the distance (radius) from the axial center of the reinforcing pipe 30 to the outer surface of the connecting portion 33 at the farthest point in a direction perpendicular to the axial center. The maximum outer diameter D4 of the operating portion 20 is twice the distance (radius) from the axial center of the operating portion 20 (or the axial center of the reinforcing pipe 30 connected to the operating portion 20) to the outer surface of the operating portion 20 at the farthest point in a direction perpendicular to the axial center. The connecting portion 33 can be fitted into the connecting recess 24 of the operating portion 20 to be connected to the operating portion 20. Note that the connecting portion 33 is not particularly limited as long as it is connectable to the operating portion 20 and has a maximum outer diameter D3 smaller than the maximum outer diameter D4 of the operating portion 20. For example, the connecting portion 33 may have an outer diameter or an inner diameter different from those of the main reinforcing pipe. The constituent material of the reinforcing pipe 30 is not particularly limited, but for example, a resin material that can be used for the above-mentioned inner layer 12 and outer layer 14 can be suitably used. The reinforcing pipe 30 may have a reinforcing member such as a braided wire or coil, like the reinforcing body 13 provided on the shaft 10. In this case, it is difficult to provide a breakable fragile portion 34 in the reinforcing pipe 30, and so the reinforcing pipe 30 may not have the fragile portion 34.

[0029] When the connecting portion 33 of the reinforcing tube 30 is connected to the operating section 20, the shaft 10 has an exposed portion 18 distal to the tip of the reinforcing tube 30 that is not covered by the reinforcing tube 30. At least a portion of the exposed portion 18, preferably the entire length of the exposed portion 18, is preferably coated with a hydrophilic coating. Examples of hydrophilic coatings include hydrophilic polymers, such as cellulose-based polymers, polyethylene oxide-based polymers, maleic anhydride-based polymers (e.g., maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers), acrylamide-based polymers (e.g., polyacrylamide, glycidyl methacrylate-dimethylacrylamide block copolymers), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and derivatives thereof. Hydrophilic polymers form a strong water immobilization layer on their surface, exhibiting high affinity for blood in blood vessels and blood vessel walls, as well as low friction. The shaft 10 may be hydrophilically coated beyond the base end of the exposed portion 18, or may be hydrophilically coated over the entire effective length L2 of the catheter 1, but from a cost perspective, it may also be hydrophilically coated over a range longer than L1 and shorter than L2.

[0030] The length L1 of the exposed portion 18 along the axial direction X is preferably 100 mm or more and 600 mm or less, more preferably 200 mm or more and 600 mm or less, and even more preferably 300 mm or more and 600 mm or less.

[0031] The effective length L2 of the catheter 1 is preferably set appropriately depending on the position where the catheter 1 is inserted into the blood vessel and the position of the lesion, and is, for example, 600 mm or more and 1500 mm or less. The effective length L2 of the catheter 1 is the length of the portion that can be inserted into a blood vessel, a sheath, etc. In this embodiment, the effective length L2 of the catheter 1 is the length from the tip of the anti-kink protector 22 to the tip of the shaft 10.

[0032] Next, the operation of the catheter 1 according to this embodiment will be described.

[0033] The catheter 1 according to this embodiment comprises a shaft 10 having a lumen 11 penetrating from the distal end to the proximal end in the axial direction X, an operating section 20 fixed to the proximal end of the shaft 10, and a reinforcing tube 30 which covers the periphery of the shaft 10, is slidable in the axial direction X relative to the shaft 10, and is provided at its proximal end with a connecting section 33 which can be connected to the operating section 20, the maximum outer diameter D3 of the connecting section 33 being smaller than the maximum outer diameter D4 of the operating section 20, and when the connecting section 33 is connected to the operating section 20, the distal end of the reinforcing tube 30 is located at a position 200 mm to 600 mm from the distal end of the shaft 10 towards the proximal end. Therefore, the catheter 1 can maintain the passability of the exposed section 18, which is not covered by the reinforcing tube 30 in a predetermined range from the distal end to the proximal end, to a lesion, while the reinforcing tube 33 can suppress excessive bending of the region proximal to the exposed section 18. Furthermore, because the connecting portion 33 of the reinforcing tube 30 can be connected to the operating section 20 fixed to the base end of the shaft 10, and the maximum outer diameter D3 of the connecting portion 33 is smaller than the maximum outer diameter D4 of the operating section 20, the connecting portion 33 of the reinforcing tube 30 is unlikely to interfere with the surgeon's operation of the operating section 20, and the reinforcing tube 30 can be slid and moved relative to the shaft 10 as needed. This provides excellent operability for the catheter 1. Furthermore, because the reinforcing tube 30 can be slid toward the distal end relative to the shaft 10 as needed, the length of the exposed portion 18 is shortened and deflection is reduced, which is expected to improve the backup performance of the guidewire inserted in the catheter in supporting the catheter 1, as well as the pushability of the catheter 1 itself.

[0034] As an example, the portion of the shaft 10 where the outside is covered with the reinforcing tube 30 can suppress excessive bending even in a blood vessel with an inner diameter of about 10 mm, such as the common iliac artery, and the exposed portion 18 at the tip of the catheter 1 can pass through a lesion in a small blood vessel with an inner diameter of about 3 to 4 mm, such as the popliteal artery. Furthermore, because the length of the exposed portion 18 of the catheter 1 is 200 mm or more and 600 mm or less, the catheter 1 can have a sufficient length to pass the tip of the catheter 1 through a lesion in a small peripheral region.

[0035] The operating unit 20 has a ring-shaped connecting recess 24 that is recessed from the distal end toward the proximal end, and the connecting portion 33 fits into the connecting recess 24 so that it can be connected to the operating unit 20. As a result, the connecting portion 33 of the reinforcing tube 30 is surrounded by the distal end of the operating unit 20, so that when the surgeon operates the operating unit 20, the connecting portion 33 of the reinforcing tube 30 is less likely to interfere with the operation, and it is easy to operate the shaft 10 fixed to the operating unit 20 and the reinforcing tube 30 as a single unit.

[0036] The reinforcing tube 30 has a breakable fragile portion 34 extending from the distal end to the proximal end. This makes it possible to break the fragile portion 34 located outside the body and remove the reinforcing tube 30 from the shaft 10 of the catheter 1 while leaving the distal end of the shaft 10 inserted into a blood vessel. This allows the catheter 1 to be used without replacement when treatment of a more peripheral region becomes necessary, and also makes it possible to insert additional devices such as a guidewire or catheter into the guiding catheter.

[0037] The reinforcing tube 30 may have a thickened portion 36 on the distal side that is thicker than on the proximal side. This allows the thickened portion 36 and the shaft 10 covered by the thickened portion 36 to form a locally less flexible portion on the proximal side of the exposed portion 18 that is inserted into the lesion, making it possible to adjust the engagement with the blood vessel, the pushability, etc.

[0038] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical spirit of the present invention. For example, as in the first modified example shown in Figure 4, the reinforcing tube 30 may have multiple protrusions 35 on its inner surface. Each protrusion 35 is pin-shaped, but may also have a ridge-like shape that is long in a predetermined direction. This creates a gap between the shaft 10 and the reinforcing tube 30, making it easier for the sterilizing gas to reach between the shaft 10 and the reinforcing tube 30. Furthermore, the contact area between the reinforcing tube 30 and the shaft 10 can be reduced, improving the sliding properties of the reinforcing tube 30 relative to the shaft 10.

[0039] 5, the connecting part 33 may be connectable to the operating part 20 by covering the outer surface of the distal end of the operating part 20. This makes it easy to operate the connecting part 33 of the reinforcing tube 30 and the operating part 20 as a single unit in the catheter 1. Furthermore, the connecting part 33 of the reinforcing tube 30 can be easily detached from the operating part 20, and the reinforcing tube 30 can be easily slid toward the distal end relative to the shaft 10 to move it away from the operating part 20 as needed.

[0040] 6, reinforcing tube 30 may have a thick portion 36 on the distal end side that is thicker than on the proximal end side. This allows thick portion 36 and shaft 10 covered by thick portion 36 to form a locally less flexible portion on the proximal end side of exposed portion 18 that is inserted into the lesion, making it possible to adjust the ability to engage with and push into the blood vessel.

[0041] Furthermore, the portion to which the connecting portion 33 of the reinforcing tube 30 is connected may be the hub 21 instead of the anti-kink protector 22 of the operating portion 20 . [Explanation of symbols]

[0042] 1 catheter 10 shaft 11 lumens 12 Inner layer 13 Reinforcement 14 Outer layer 15 Wire rod 16 Main shaft part 17 Shaft tip 18 Exposed part 20 Control section 21 Hub 22 Anti-kink protector 23 Connecting protrusion 24 Connection recess 30 Reinforcing pipe 31 Tapered section 32 Main part of reinforcement pipe 33 Connecting part 34 Weak part 35 Protrusion 36 Thick part D1 Outer diameter of main shaft part D2 Outer diameter of main part of reinforcing pipe D3 Maximum outer diameter of connecting part D4 Maximum outer diameter of the operating part L1 Length along the axial direction of the exposed part L2 Effective length of catheter X axis direction

Claims

1. A shaft having a lumen that communicates in an axial direction from a tip end to a base end; An operation unit fixed to a base end of the shaft; a reinforcing tube that covers the shaft and is slidable in the axial direction relative to the shaft, the reinforcing tube having a connecting portion at a base end that can be connected to the operating portion; The maximum outer diameter of the connecting portion is smaller than the maximum outer diameter of the operating portion, A catheter characterized in that, when the connecting portion is connected to the operating portion, the tip of the reinforcing tube is located at a position 200 mm to 600 mm away from the tip of the shaft toward the base end.

2. The operation section has a ring-shaped connecting recess recessed from a distal end side toward a proximal end side, The catheter according to claim 1 , wherein the connecting portion is capable of being connected to the operation portion by entering the connecting recess.

3. The catheter according to claim 1 , wherein the connecting portion is adapted to cover an outer surface of the distal end side of the operating portion and is connectable to the operating portion.

4. The catheter according to any one of claims 1 to 3, wherein the reinforcing tube has a plurality of protrusions on its inner surface.

5. The catheter according to any one of claims 1 to 4, wherein the reinforcing tube has a breakable weakened portion extending from the distal end to the proximal end.

6. The catheter according to any one of claims 1 to 5, wherein the reinforcing tube has a thick portion on a distal end side that is thicker than a proximal end side.

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