JP2023149727A - catheter assembly - Google Patents

Abstract

To provide a catheter assembly with suitable pushability.SOLUTION: A catheter assembly 100 includes a catheter 60, a catheter hub 110, a guide wire 10, and a guide wire hub 120. The guide wire has a guide wire stiffness changing section 35 whose stiffness gradually decreases from the proximal side to the distal side, and the catheter has a catheter stiffness changing section 85 whose stiffness gradually decreases from the proximal side to the distal side. When the catheter hub and the guide wire hub are connected, the difference between adjacent bending load values for every 50 mm within 400 mm from the distal end is 20 gf or less.SELECTED DRAWING: Figure 7

Description

The present invention relates to catheter assemblies.

2. Description of the Related Art Catheter devices have conventionally been used to perform treatments within living body lumens. A guide wire with a flexible core wire is used to guide the catheter device to a target site in a biological lumen. For example, trance catheter arterial chemo embolization (TACE) is a treatment in which a catheter is advanced from the hepatic artery closer to the tumor and selectively necrotized the tumor by injecting anticancer drugs or embolic substances. It's a method. In this hepatic artery chemoembolization, a guide wire is used to advance the catheter.

When guiding a catheter to a target site, a widely used technique is to advance the catheter while following a guide wire that is placed in front of it. In addition, it is also common to use a one-piece catheter assembly in which the guidewire is inserted into the catheter, so that both the guidewire and catheter are advanced together.

The one-piece catheter assembly includes a catheter hub attached to the proximal end of the catheter, and a guidewire hub attached to the proximal end of the guidewire and removably connected to the catheter hub. The catheter hub and the guidewire hub are connected to each other in a state where a predetermined range from the distal end of the guidewire is exposed from the distal end of the catheter.

A biological lumen has a complicatedly curved or meandering shape. 2. Description of the Related Art In order to improve the operability when passing a guidewire into a living body lumen, a guidewire is known that is provided with a stiffness changing portion whose stiffness gradually decreases from the proximal end toward the distal end. The stiffness of the stiffness changing section is changed by gradually decreasing the diameter of the core wire.

When applying a guidewire having a stiffness-changing portion to a catheter assembly of an integral structure type, simply connecting the guidewire and the catheter may give an uncomfortable feeling to the operator's usability. For example, when the rigidity of the catheter is relatively high, the rigidity changes (increases) rapidly from the distal end to the proximal end with the catheter distal end, which is the starting point where the guide wire is exposed, as the boundary. For this reason, even though a flexible guidewire is used, the operability of the monolithic catheter assembly is hindered.

In connection with this, for example, Patent Document 1 below discloses a catheter assembly that can suppress the occurrence of discomfort in usability and improve operability.

International Publication 2018/181178

As a result of intensive study of the above-mentioned prior documents, the present inventors found that in the catheter assembly disclosed in Patent Document 1, as shown in FIG. Due to the bending load value increasing significantly by approximately 35gf in the range of 300mm to 360mm, there is a possibility that the pushability to efficiently transmit the pushing force to the tip side is insufficient. I discovered that.

The present invention aims to solve the above-mentioned problems, and aims to provide a catheter assembly suitably equipped with pushability.

A catheter assembly according to the present invention that achieves the above object includes a catheter having a shaft portion having a lumen, a catheter hub attached to a proximal end portion of the catheter, and a flexible core wire having the shaft portion. and a guidewire hub that is attached to the proximal end of the guidewire and detachably connected to the catheter hub. The guide wire has a guide wire stiffness changing portion whose stiffness gradually decreases from the proximal end toward the distal end. The catheter has a catheter stiffness changing section whose stiffness gradually decreases from the proximal end to the distal end. In the catheter assembly, when the catheter hub and the guidewire hub are connected, the difference between adjacent bending load values for every 50 mm within 400 mm from the tip is 20 gf or less.

According to the catheter assembly configured as described above, when the catheter hub and the guidewire hub are connected, the difference between adjacent bending load values every 50 mm within 400 mm from the tip is 20 gf or less. Therefore, since the bending load value can change smoothly, it is possible to provide a catheter assembly with suitable pushability.

FIG. 1 is a schematic diagram showing a one-piece catheter assembly according to the present embodiment. FIG. 3 is a schematic diagram showing the catheter assembly with the catheter hub and guidewire hub disconnected. FIG. 3 is an enlarged axial cross-sectional view of the distal end portion of the catheter assembly. FIG. 3 is an axial cross-sectional view of the guide wire. FIG. 2 is an axial cross-sectional view showing an enlarged distal end portion of the guide wire. FIG. 2 is a diagram schematically showing the progress of an integral structure type catheter assembly in hepatic artery chemoembolization. 2 is a graph showing bending load values for a single catheter, a single guidewire, and a monolithic catheter assembly along the axial position of the guidewire. 2 is a graph illustrating bending load values for the catheter assembly along the axial position of the core wire. 2 is a graph showing the diameter of the core wire of the guidewire along the axial position of the core wire. FIG. 2 is a cross-sectional view showing a schematic configuration of a measurement test device that measures bending load values.

Embodiments of the present invention will be described below with reference to the attached drawings. Note that the following description does not limit the technical scope or meaning of terms described in the claims. Further, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

The configuration of a catheter assembly 100 according to this embodiment will be described with reference to FIGS. 1 to 6. FIG. 1 is a schematic diagram showing a monolithic catheter assembly 100 according to the present embodiment. FIG. 2 is a schematic diagram illustrating catheter assembly 100 with catheter hub 110 and guidewire hub 120 disconnected. FIG. 3 is an enlarged axial cross-sectional view of the distal end portion of the catheter assembly 100. FIG. 4 is an axial cross-sectional view of the guidewire 10. FIG. 5 is an enlarged axial cross-sectional view of the distal end portion of the guide wire 10. As shown in FIG. FIG. 6 is a diagram schematically showing how the catheter 60 is advanced along the guide wire 10 in hepatic artery chemoembolization.

In the description of this specification, the longitudinal direction in which the shaft portion 70 of the catheter 60 and the core wire 20 of the guide wire 10 extend (the left-right direction in FIG. 1A) is defined as the axial direction, and is indicated by an arrow X in each figure. A direction perpendicular to the axial direction is defined as a radial direction, and is indicated by an arrow R in FIGS. 3 and 5. In the catheter assembly 100, the side that is inserted into the living body (into the blood vessel) is defined as the tip side (distal side, the left side in FIG. 1A), which is indicated by arrow X1 in each figure and is located on the opposite side from the tip side. The side on which manual operations are performed is defined as the proximal side (proximal side, right side in FIG. 1A), and is indicated by arrow X2 in each figure. In this specification, the term "tip part" means a part that includes a certain range in the axial direction from the tip (the most proximal end), and the term "base part" refers to a part that includes a certain range in the axial direction from the base end (the most proximal end). shall mean a part.

As shown in FIGS. 1-5, catheter assembly 100 includes a catheter 60 having a shaft portion 70 having a lumen 71, a catheter hub 110 attached to the proximal end of catheter 60, and a flexible core wire. 20 and can be inserted into the lumen 71 of the shaft portion 70, and a guidewire hub 120 that is attached to the proximal end of the guidewire 10 and detachably connected to the catheter hub 110. The guidewire 10 has a guidewire stiffness changing portion 35 whose stiffness gradually decreases from the proximal end toward the distal end. The catheter 60 has a catheter stiffness changing section 85 whose stiffness gradually decreases from the proximal end to the distal end.

The monolithic catheter assembly 100 is inserted into a biological lumen and used to guide both the guidewire 10 and the catheter 60 together to a target site in the biological lumen.

For example, as shown in FIG. 6, in hepatic artery chemoembolization (TACE), a catheter 60 is advanced from an artery 91 of a liver 90 to near a tumor 92, and an anticancer drug or an embolic substance is delivered. This is a treatment method in which the tumor is selectively necrotized by injection. In this hepatic artery chemoembolization, a monolithic catheter assembly 100 is used.

A biological lumen has a complicatedly curved or meandering shape. Therefore, when the catheter assembly 100 passes through a living body lumen, pushability is required to efficiently transmit the pushing force to the distal end side.

The configuration of each part will be explained in detail below.

(catheter 60)
As shown in FIG. 1, the catheter 60 has a substantially circular cross section and includes an elongated shaft portion 70 that can be introduced into a living body, and a catheter hub 110 that is connected to the proximal end of the shaft portion 70. have. The catheter 60 has an anti-kink protector (strain relief) 115 near the connection between the shaft portion 70 and the catheter hub 110. Note that the catheter 60 is not limited to the form shown in FIG. 1A, and may not include the kink-resistant protector 115.

As shown in FIG. 3, the shaft portion 70 is configured as a flexible tubular member in which an inner cavity 71 extending in the axial direction is formed. The length of the shaft portion 70 is preferably set to be approximately 700 mm to 2000 mm, preferably approximately 1000 mm to 1500 mm, although the preferred value varies depending on the case, such as the position and thickness of the blood vessel to which it is applied. The preferred outer diameter (thickness) of the shaft portion 70 varies depending on the case, such as the position and thickness of the blood vessel to which it is applied, but is set to, for example, about 0.4 mm to 3.0 mm, and is preferably set to 0.4 mm to 3.0 mm. It is set to about .5 mm to 1.1 mm, more preferably about 0.85 mm to 0.91 mm. The preferred value of the inner diameter of the shaft portion 70 (outer diameter of the inner cavity 71) varies depending on the case, such as the thickness of the guide wire 10 to be inserted, the position and thickness of the blood vessel to which it is applied, and is, for example, 0.3 mm to 0.3 mm. It is set to about 2.3 mm, preferably about 0.4 mm to 0.8 mm, and more preferably about 0.68 mm to 0.72 mm.

As shown in FIG. 3, the shaft portion 70 includes a tubular inner layer 72 and an outer layer 73 disposed to cover the outer surface of the inner layer 72. A contrasting part 74 made of a material that is opaque to X-rays is disposed at a part of the distal end of the shaft part 70 between an inner layer 72 and an outer layer 73. Note that in the catheter 60 according to the present embodiment, since the bending load value moves smoothly, there is no need to provide a distal tip for adding flexibility to the distal end of the shaft portion 70. The shaft portion 70 is provided with a reinforcing body 75 formed by braiding wire rods on the proximal side of the portion where the contrast portion 74 is formed.

The inner layer 72 is made of a material softer than the guide wire 10, which will be described later, and includes, for example, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and FEP (tetrafluoroethylene). Resins such as fluorine-containing ethylenic polymers such as ethylene-hexafluoropropylene copolymer (ethylene-hexafluoropropylene copolymer) and ETFE (ethylene-tetrafluoroethylene copolymer), polyamides such as nylon, and polyamide elastomers such as nylon elastomer can be used. . Among the above, PTFE (polytetrafluoroethylene) or PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), which have high lubricity, can be preferably used. By using these materials, it is possible to reduce the frictional resistance on the inner surface, thereby improving the operability of the guide wire 10 inserted into the lumen 71 of the shaft portion 70 when using the catheter 60. can. As PTFE (polytetrafluoroethylene), one that does not have an endothermic peak at 370° C. and has a tensile strength of 350% or more in the temperature raising process of differential scanning calorimetry (DSC) can be used.

Examples of the constituent material of the outer layer 73 include polyolefin (for example, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these), polyvinyl chloride, etc. , polyamide, polyester, polyester elastomer, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or a mixture thereof. The outer layer 73 may have a multilayer structure formed by laminating different resin materials. Further, it is also possible to form a hydrophilic coat layer or the like by coating the outer surface of the outer layer 73 with a material made of a hydrophilic polymer.

The contrast section 74 is made of a metal material or a resin material that has higher X-ray opacity than the inner layer 72 and the outer layer 73. The radiopaque metal material can be made of, for example, platinum, gold, silver, tungsten, or an alloy thereof. Furthermore, the resin material having X-ray opacity can be constructed by coating or containing an X-ray contrast substance in a resin material or the like that does not have X-ray opacity. Examples of the X-ray contrast substance include powdered inorganic materials such as tungsten, barium sulfate, and bismuth oxide.

Catheter hub 110 is attached to the proximal end of shaft portion 70 in a liquid-tight manner using an adhesive, a fixture (not shown), or the like. As shown in FIG. 1, the catheter hub 110 includes a main body portion 111 having an inner cavity, and a pair of handle portions 112 formed to protrude from the sides of the main body portion 111. The catheter hub 110 functions as an insertion port for the guide wire 10 into the lumen 71 of the shaft portion 70 and an injection port for a contrast medium, a drug solution, an embolic substance, and the like. Catheter hub 110 functions as a grip when operating catheter 60. A male threaded portion 113 is formed at the base end of the main body portion 111 .

The catheter hub 110 is made of, for example, synthetic resin such as polycarbonate, polyolefin, styrene resin, polyamide, or polyester, stainless steel, aluminum, or aluminum alloy. Polyolefins are, for example, polyethylene, polypropylene, ethylene-propylene copolymers.

The kink-resistant protector 115 can be made of an elastic material provided so as to surround a portion of the base end of the shaft portion 70. As the constituent material of the kink-resistant protector 115, for example, natural rubber, silicone resin, etc. can be used.

The catheter 60 has a catheter stiffness changing portion 85 whose stiffness gradually decreases from the proximal end to the distal end. As shown in FIG. 7, the bending load value in the catheter stiffness changing section 85 increases stepwise from the distal end to the proximal end.

In this embodiment, the catheter stiffness changing section 85 gradually decreases the stiffness of the shaft section 70 of the catheter 60 from the proximal end toward the distal end. As shown in FIG. 1, the catheter stiffness changing section 85 includes four regions, a first region 81, a second region 82, a third region 83, and a fourth region 84, in order from the proximal end side to the distal end side of the shaft section 70. It is divided into separate areas. The base region 80 continuous to the base end of the first region 81 has constant rigidity along the axial direction.

In FIG. 7, the base region 80 is indicated by the symbol 80a, the first region 81 is indicated by the symbol 81a, the second region 82 is indicated by the symbol 82a, the third region 83 is indicated by the symbol 83a, and the fourth region is indicated by the symbol 83a. 84 is designated by the reference numeral 84a.

The catheter stiffness changing section 85 can be configured, for example, by arranging a plurality of materials having different hardness along the axial direction. In this embodiment, the outer layer 73 of the shaft portion 70 has a plurality of regions having different hardness along the axial direction, and the hardness of the material constituting each region decreases toward the distal end (the hardness decreases toward the distal end). flexibility is increasing). The hardness of the material forming the outer layer 73 in the fourth region 84 is lower than the hardness of the material forming the outer layer 73 in the third region 83. The hardness of the material forming the outer layer 73 in the third region 83 is lower than the hardness of the material forming the outer layer 73 in the second region 82 . The hardness of the material forming the outer layer 73 in the second region 82 is lower than the hardness of the material forming the outer layer 73 in the first region 81 . The hardness of the material forming the outer layer 73 in the first region 81 is lower than the hardness of the material forming the outer layer 73 in the base region 80 . Accordingly, in the shaft portion 70 of the catheter 60, the fourth region 84 is configured to be more flexible than the third region 83, the third region 83 is configured to be more flexible than the second region 82, and the second region 82 is configured to be more flexible than the first region 83. The first region 81 is configured to be more flexible than the base region 80 .

An example of the hardness of the constituent materials will be given. Hardness is measured using a Type D durometer according to ASTM D2240. The fourth region 84 is located at the most distal side of the catheter and is therefore the most flexible, and the hardness of its constituent material is preferably 20D to 40D, more preferably 25D to 35D. The third region 83 is the second most flexible after the fourth region 84, and the hardness of its constituent material is preferably 25D to 60D, more preferably 30D to 40D. The second region 82 is the second most flexible after the third region 83, and the hardness of its constituent material is preferably 25D to 60D, more preferably 30D to 40D. The first region 81 requires appropriate hardness in order to transmit the operator's operation from the proximal side to the distal side, and the hardness of its constituent material is preferably 40D to 80D, and preferably 60D to 70D. It is more preferable. The base region 80 needs to have sufficient hardness for direct operation by the operator, and the hardness of its constituent material is preferably 50D to 90D, more preferably 70D to 80D.

In order to achieve these hardnesses, the above-mentioned constituent materials are used for the outer layer 73, but a plurality of these materials may be combined. Additionally, additives may be added to the constituent materials in order to adjust the hardness to an optimal range. The thickness of the outer layer 73 can also be changed to adjust the hardness.

The axial length of each region in the catheter stiffness changing section 85 depends on the aspect (number of regions, axial length of each region, etc.) of the guidewire stiffness changing section 35 in the guidewire 10 inserted and connected to the catheter 60. Its preferred values are different. The preferable axial length of each region in the catheter stiffness changing section 85 differs depending on the dimension of exposing the distal end side of the guide wire 10 from the distal end of the shaft section 70. For example, the axial length Lc1 of the first region 81 is 50 mm, the axial length Lc2 of the second region 82 is 150 mm, the axial length Lc3 of the third region 83 is 150 mm, and the axial length Lc3 of the fourth region 84 is 50 mm. The directional length Lc4 is 100 mm. The axial length of the base region 80 varies depending on the product length. The length of the exposed distal end of the guide wire 10 is 100 mm.

The thickness of each inner layer 72 in the shaft portion 70 is constant over the entire length in the axial direction. Although the thickness of the inner layer 72 is not particularly limited, it is, for example, 0.015 mm.

The respective bending load values for the catheter 60 alone, the guidewire 10 alone, and the integral structure type catheter assembly 100 will be described later.

(Guide wire 10)
Referring to FIGS. 1, 4, and 5, guidewire 10 includes a core wire 20 extending in the axial direction and a guidewire hub 120 connected to the proximal end of core wire 20. The guide wire 10 includes a marker section 40 disposed at the distal end of the core wire 20 and a coating layer 50 that covers the core wire 20.

The length of the guide wire 10 is preferably 500 to 4000 mm, for example, although the preferable value varies depending on the case, such as the position and thickness of the blood vessel to which it is applied. Although the preferable value of the outer diameter (thickness) of the main body portion 30 varies depending on the case, such as the position and thickness of the blood vessel to which it is applied, it is preferable that the outer diameter is, for example, 0.15 to 2.0 mm.

As shown in FIG. 2, the proximal end of the guidewire 10 is attached to the distal wall of the guidewire hub 120. The guidewire hub 120 has a main body part 121 having an inner cavity and a ring part 122 disposed on the distal end side of the main body part 121. When injection molding the main body portion 121, the proximal end portion of the guide wire 10 is inserted. The guidewire hub 120 is used in conjunction with the catheter hub 110 and functions as an inlet for injecting a liquid such as a contrast medium into the lumen 71 of the shaft portion 70 . Liquid can be injected or withdrawn while the guide wire 10 remains inserted into the lumen 71 of the shaft portion 70. The ring portion 122 has a female threaded portion (not shown) formed on its inner circumferential surface to be screwed into the male threaded portion 113 of the catheter hub 110 . The ring portion 122 can rotate relative to the main body 121, but by engaging with a convex portion (not shown) formed on the outer periphery of the main body 121, the ring portion 122 rotates from the main body 121 in the distal direction. Getting out is restricted.

As shown in FIG. 1, the distal end of the guidewire hub 120 is fitted into the lumen of the catheter hub 110, and the ring portion 122 is rotated to screw the male threaded portion 113 and the female threaded portion together, and tighten with a certain amount of torque. Thereby, catheter hub 110 and guidewire hub 120 are fluid-tightly connected, and this connected state is maintained. The male threaded portion 113 and the ring portion 122 having the female threaded portion constitute a locking means for fixing the connected state of the catheter hub 110 and the guidewire hub 120.

The constituent material of the guidewire hub 120 is, for example, a synthetic resin such as polycarbonate, polyolefin, styrene resin, polyamide, or polyester. Polyolefins are, for example, polyethylene, polypropylene, ethylene-propylene copolymers.

Referring to FIG. 5, the marker portion 40 is arranged to cover the tip core portion 34 within a certain range in the axial direction. The marker section 40 is composed of a wire wound spirally around the tip core section 34 . The distal end of the marker section 40 is fixed near the distal end of the distal core section 34 via a fixing material 41. The proximal end of the marker portion 40 is fixed near the proximal end of the distal core portion 34 via a fixing material 42 . The fixing materials 41 and 42 can be made of, for example, various adhesives, solders, or the like.

The marker section 40 is made of a material that is X-ray opaque (X-ray contrast property). Examples of the X-ray opaque material include metal materials such as noble metals such as gold, platinum, and tungsten, and alloys containing these metals (eg, platinum-iridium alloy). By providing the marker portion 40 on the distal core portion 34, the guidewire 10 can be inserted into the living body while confirming the position of the distal end portion of the guidewire 10 under X-ray fluoroscopy.

The covering layer 50 is made of a resin material and is formed to cover the entire core wire 20 including the marker portion 40. The tip of the covering layer 50 preferably has a rounded shape so as not to damage the inner wall of the living body lumen.

Preferably, the coating layer 50 is made of a material that can reduce friction. As a result, the frictional resistance (sliding resistance) between the guidewire 10 and the catheter 60 and the living body lumen through which the guidewire 10 is inserted is reduced, the slidability is improved, and the operability of the guidewire 10 can be improved. Further, since the sliding resistance of the guide wire 10 is reduced, kinking (bending) and twisting of the guide wire 10 can be more reliably prevented.

The resin material constituting the coating layer 50 is preferably a relatively flexible material, such as polyolefin such as polyethylene or polypropylene, polyvinyl chloride, polyester (PET, PBT, etc.), polyamide, polyimide, polyurethane, polystyrene, polycarbonate. , silicone resins, fluororesins (PTFE, ETFE, PFA, etc.), composite materials thereof, various rubber materials such as latex rubber and silicone rubber, and composite materials combining two or more of these. Among the above materials, it is more preferable to use urethane resin from the viewpoint of further improving flexibility. As a result, the tip of the guide wire 10 can be made flexible, so that damage to the inner wall of the living body lumen can be prevented when the guide wire 10 is inserted into the living body lumen. .

The thickness of the coating layer 50 is not particularly limited, but is preferably, for example, 5 to 500 μm. Note that the covering layer 50 is not limited to a single layer structure, and may be configured by laminating a plurality of layers.

The coating layer 50 is preferably covered with a hydrophilic coating layer (not shown). Since the sliding property is improved by being covered with the hydrophilic coating layer, it is possible to further prevent the guide wire 10 from getting caught on the inner wall of the biological lumen or the catheter 60.

The constituent material of the hydrophilic coating layer is not particularly limited, but examples include cellulose-based polymers, polyethylene oxide-based polymers, maleic anhydride-based polymers (e.g., methyl vinyl ether-maleic anhydride copolymer), etc. Known materials such as maleic anhydride copolymers), acrylamide-based polymers (for example, polyacrylamide, block copolymers of polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA)), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, etc. Examples include hydrophilic substances.

The thickness of the hydrophilic coating layer is not particularly limited, but is preferably, for example, 0.1 to 100 μm.

As shown in FIG. 4, the guidewire 10 has a guidewire stiffness changing portion 35 whose stiffness gradually decreases from the proximal end toward the distal end.

In this embodiment, the guidewire stiffness changing section 35 gradually decreases the stiffness of the core wire 20 from the proximal end toward the distal end. The main body portion 30 has constant rigidity along the axial direction.

The guidewire stiffness changing section 35 can be configured, for example, by varying the diameter of the core wire 20 along the axial direction. The guidewire stiffness changing portion 35 has a diameter d5 that gradually decreases from the main body portion 30 toward the distal core portion 34.

FIG. 8 is a graph showing the bending load value of the core wire 20 of the guide wire 10 along the axial position of the core wire 20. FIG. 9 shows the diameter of the core wire 20 of the guide wire 10 along the axial position of the core wire 20. This is a graph showing Note that the coating layer 50 covering the core wire 20 does not substantially contribute to the rigidity of the guide wire 10. Therefore, the stiffness of the core wire 20 can be considered as the stiffness of the guide wire 10, and the guide wire stiffness changing portion 35 also indicates the stiffness changing portion of the core wire 20.

Core wire 20 has flexibility. As shown in FIGS. 4 and 5, the core wire 20 includes a distal core portion 34, a main body portion 30, and a guidewire rigidity changing portion 35. The distal core portion 34 is the most flexible portion of the entire length of the core wire 20, including the distal end. The main body portion 30 is a portion that is located closer to the proximal end than the distal core portion 34 and has a constant diameter d0 along the axial direction. The guidewire rigidity changing portion 35 constitutes a portion from the distal end of the main body portion 30 to the proximal end of the distal core portion 34, and is a portion whose rigidity gradually decreases from the main body portion 30 toward the distal core portion 34.

8 and 9, the region of the distal core portion 34 is designated by the reference numeral 34a, the region of the body portion 30 is designated by the reference numeral 30a, and the region of the guidewire stiffness variation 35 is designated by the reference numeral 35a.

In this embodiment, core wire 20 is formed from a single material. The diameter of core wire 20 varies along the axial direction. Thereby, the stiffness of the core wire 20 changes along the axial direction.

The constituent material of the core wire 20 is not particularly limited, but for example, Ni--Ti alloy, stainless steel, superelastic alloy, etc. can be used.

The main body portion 30 has a constant diameter d0 along the axial direction. The tip core portion 34 also has a constant diameter d4 along the axial direction.

In this specification, "having a constant diameter along the axial direction" is not limited to having physically the same diameter. As long as the rigidity (bending rigidity and torsional rigidity) of the main body portion 30 and the tip core portion 34 can be made approximately constant, it is sufficient that the outer diameter dimension is approximately constant.

The guidewire stiffness changing section 35 can be configured, for example, by varying the diameter of the core wire 20 along the axial direction. The guidewire stiffness changing portion 35 has a diameter d5 that gradually decreases from the main body portion 30 toward the distal core portion 34.

In FIG. 9, the bending load value and diameter of the core wire of the comparative example are shown by broken lines. The core wire of the contrast ratio has, in order from the proximal end, a first taper part, a second taper part, and a third taper part, and the slope of the change in diameter in the first taper part is equal to the gradient in the diameter change in the second taper part. The slope of the change in diameter is configured to be greater than the slope of the change in diameter. Therefore, as shown in FIG. 9, a bending point where the gradient of the diameter bends and changes occurs at the boundary between the first tapered part and the second tapered part.

As shown in FIG. 8, in this embodiment, the range of the stiffness change portion in the core wire is up to 450 mm from the leading edge of the core wire.

As shown in FIG. 8, it can be seen that in the guidewire stiffness changing section 35, as the distance x from the tip of the core wire 20 according to this embodiment increases, the bending load value y of the catheter assembly increases. The present inventors calculated an approximate expression corresponding to the correlation between the distance x from the tip of the core wire 20 in the guidewire stiffness changing section 35 and the bending load value y of the catheter assembly. As a result, the following approximate formula was calculated.
y=0.0000070x ³ -0.0016696x ² +0.3726389x+8.3177570
According to the guide wire 10 configured in this way, the bending load value of the catheter assembly increases as the distance from the tip of the core wire 20 increases, so pushability improves. Further, according to the guide wire configured as above, the bending load value y is y=0.0000070x ³ -0.0016696x ² +0.3726389x+8.3177570, where x is the length from the tip of the core wire. Since the diameter of the core wire also changes continuously, no boundary is formed as in the guide wire disclosed in the comparative example. Therefore, pushability is improved. From the above, it is possible to provide the guidewire 10 suitably equipped with pushability.

The diameter d5 on the proximal end side of the guidewire stiffness change section 35 is approximately the same as the diameter d0 of the main body section 30 so that the boundary between the main body section 30 and the guidewire stiffness change section 35 is a continuous surface. Similarly, the diameter d5 on the distal end side of the guidewire stiffness changing section 35 is approximately the same as the diameter d4 of the distal core section 34.

As used herein, the term "continuous surface" means that the outer surface of the core wire 20 is smooth enough to prevent the guide wire 10 from getting caught on the inner wall of the biological lumen or the catheter 60. For example, if the diameter d5 on the proximal end side of the guidewire stiffness variable portion 35 and the diameter d0 of the main body portion 30 are not formed to be approximately the same, a slight A difference in level occurs. However, due to the coating layer 50, the outer surface of the guide wire 10 becomes a substantially smooth surface, which may prevent the guide wire 10 from getting caught on the inner wall of a living body lumen. In such a case, even if the core wire 20 has a slight step, the outer surface of the core wire 20 can be considered to be a "continuous surface."

The core wire 20 is formed by cutting or polishing a forming material. Each region of the main body portion 30, the guidewire stiffness change portion 35, and the distal core portion 34 can be formed at the same time. Each region can also be formed separately and sequentially. The core wire 20 is not limited to cutting or polishing, but may be formed by etching or laser processing.

Next, with reference to FIG. 7, the bending load value of the catheter assembly 100 according to this embodiment will be explained. The bending load value is obtained by the method described below.

As shown in FIG. 7, within 400 mm from the tip, the difference between adjacent bending load values every 50 mm is 20 gf or less. Further, among the bending load values that are adjacent to each other every 50 mm within 400 mm from the tip, the bending load value on the tip side is 50% or more of the bending load value on the proximal side. According to the catheter assembly 100 configured in this way, pushability can be suitably provided.

The above-mentioned bending load values are obtained by bending load value measurements described below.

FIG. 10 is a sectional view showing a schematic configuration of a measurement test device 200 that measures bending load values.

Referring to FIG. 10, measurement test apparatus 200 includes a fixing jig 201 that supports a long measurement object 205, and a push-down jig 202 arranged above fixing jig 201. The fixing jig 201 has a pair of support legs 203 that support the measurement target 205 at two points. The distance Ld between the support legs 203 is 25.4 mm. A groove 204 into which the object to be measured 205 fits is formed on the upper surface of the support leg 203 . The push-down jig 202 is configured to be able to move up and down with respect to the fixing jig 201. The push-down jig 202 is configured to be able to freely adjust the speed at which the object to be measured 205 is pushed down and the dimension at which the object to be measured 205 is pushed down.

The measurement object 205 is a single core wire 20 of the guide wire 10, a single shaft portion 70 of the catheter 60, and a catheter assembly 100 in which the catheter 60 and the guide wire 10 are connected.

In this embodiment, the bending load value was measured using the measurement test device 200 under the following conditions, and the bending load value was obtained. That is, the measurement object 205 is supported at two points with an interval of 25.4 mm. The push-down jig 202 moves at a speed of 5 mm/min. The supported central portion of the object to be measured 205 is vertically pushed down by the push-down jig 202 . The bending load value was determined by measuring the load at the time when the measurement object 205 was pushed down by 2 mm. Since it was necessary to support the measurement object 205 at two points, the measurement of the bending load value was started from a position 20 mm from the leading edge of the measurement object 205. The measurement start position of the core wire 20 is the position of the tip of the guide wire stiffness changing section 35. In FIGS. 7 and 8, measured values from a position 20 mm from the leading edge of the core wire 20 alone, the shaft portion 70 alone, and the catheter assembly 100 are plotted, and FIG. Measured values from a position of 20 mm were plotted.

In this embodiment, the axial length of the core wire 20 has a length used for hepatic artery chemoembolization. In this case, the axial length L of the guidewire stiffness changing section 35 is preferably 360 to 450 mm, more preferably 360 to 400 mm. By using the guidewire stiffness changing section 35 having the length L, the region of the core wire 20 that reaches the part extending from the aorta to the common hepatic artery (300 to 400 mm from the tip) becomes flexible, allowing hepatic artery chemoembolization. can be suitably implemented.

As described above, the catheter assembly 100 according to the present embodiment includes a catheter 60 having a shaft portion 70 having a lumen, a catheter hub 110 attached to the proximal end of the catheter 60, and a flexible core wire. 20 and can be inserted into the inner lumen of the shaft portion 70, and a guidewire hub 120 that is attached to the proximal end of the guidewire 10 and detachably connected to the catheter hub 110. The guidewire 10 has a guidewire stiffness changing portion 35 whose stiffness gradually decreases from the proximal end toward the distal end. The catheter 60 has a catheter stiffness changing section 85 whose stiffness gradually decreases from the proximal end to the distal end. When the catheter hub 110 and the guidewire hub 120 are connected, the difference between adjacent bending load values every 50 mm within 400 mm from the tip is 20 gf or less. According to the catheter assembly 100 configured in this way, the change in the bending load value can be made gentle, so it is possible to provide the catheter assembly 100 suitably equipped with pushability.

The core wire 20 also includes a distal core section 34 that is the most flexible of the entire length of the core wire 20, including the distal end, and a main body section that is located on the proximal side of the distal core section 34 and has a constant diameter along the axial direction. 30, and a guidewire rigidity changing section 35 that constitutes a portion from the distal end of the main body section 30 to the proximal end of the distal core section 34, and whose rigidity gradually decreases from the main body section 30 toward the distal core section 34. By supporting the core wire 20 at two points with a spacing of 25.4 mm, and measuring the load at the time when the supported central portion is vertically pushed down 2 mm by a push-down jig 202 that moves at a speed of 5 mm/min. The bending load value y of the resulting catheter assembly is expressed by the approximate formula y=0.0000070x ³ -0.0016696x ² +0.3726389x+8.3177570, where x is the length from the tip of the core wire. According to the guide wire 10 configured in this way, the bending load value y is y=0.0000070x ³ -0.0016696x ² +0.3726389x+8.3177570, where x is the length from the tip of the core wire 20. Therefore, the bending load value y of the catheter assembly increases with increasing distance from the tip. Therefore, pushability is improved. Further, according to the guide wire 10 configured as described above, the bending load value y of the catheter assembly is y=0.0000070x ³ -0.0016696x ² where x is the length from the tip of the core wire 20. Since it is expressed as +0.3726389x+8.3177570, the diameter d5 of the core wire 20 also changes continuously. Therefore, pushability is improved. From the above, it is possible to provide the guidewire 10 suitably equipped with pushability.

Further, as described above, the catheter assembly 100 according to the present embodiment includes the catheter 60 having the shaft portion 70 having a lumen, the catheter hub 110 attached to the proximal end of the catheter 60, and the flexible The guide wire 10 has a core wire 20 that can be inserted into the inner cavity of the shaft portion 70, and a guide wire hub 120 that is attached to the proximal end of the guide wire 10 and detachably connected to the catheter hub 110. The guidewire 10 has a guidewire stiffness changing portion 35 whose stiffness gradually decreases from the proximal end toward the distal end. The catheter 60 has a catheter stiffness changing section 85 whose stiffness gradually decreases from the proximal end to the distal end. When the catheter hub 110 and the guidewire hub 120 are connected, among the bending load values that are adjacent every 50 mm within 400 mm from the distal end, the bending load value on the proximal end is 50% of the bending load value on the distal end. % or more. According to the catheter assembly 100 configured in this way, a sudden change in the bending load value of the catheter assembly 100 can be suppressed, so that the catheter assembly 100 with suitable pushability can be provided.

Although the catheter assembly 100 according to the present invention has been described above through the embodiments, the present invention is not limited to each configuration described in the specification, and may be modified as appropriate based on the claims. Is possible.

For example, although the catheter assembly 100 used for hepatic artery chemoembolization is taken as an example, it goes without saying that the catheter assembly 100 of the present invention can be used for other procedures. Each of the catheter 60 and the guide wire 10 may have an appropriate length depending on the applied procedure.

Regarding the guide wire 10, a configuration has been described in which the core wire 20 is formed from a single material and the stiffness is varied along the axial direction by varying the diameter along the axial direction (that is, tapered). However, the present invention is not limited to this case. By using different materials for each of the main body portion 30, the guidewire stiffness changing portion 35, and the distal core portion 34, the stiffness can be changed along the axial direction. The main body portion 30, the guidewire rigidity variable portion 35, and the distal core portion 34, which are made of different constituent materials, can be joined by an appropriate known method such as welding, welding, or adhesive. Each portion of core wire 20 may be formed using a combination of different materials of construction and a tapered shape.

Regarding the catheter 60, a configuration has been described in which the rigidity is changed along the axial direction by changing the hardness of the outer layer 73 of the shaft portion 70 along the axial direction, but the present invention is not limited to this case. do not have. By forming the shaft portion 70 from the same material but changing the thickness of the material along the axial direction, the rigidity can be changed along the axial direction. For example, the outer layer 73 of the shaft portion 70 has a plurality of regions having different thicknesses along the axial direction, and the thickness of each region decreases toward the distal end (flexibility decreases toward the distal end). increase). The stiffness of catheter 60 can be varied by a combination of both material hardness and wall thickness.

10 guide wire,
20 core wire,
30 main body,
34 Tip core part,
35 Guidewire stiffness changing section,
40 marker section,
50 coating layer,
60 catheter,
70 shaft part,
71 lumen,
72 Inner layer,
73 outer layer,
74 Contrast department,
75 Reinforcement body,
80 base area,
81 First area,
82 Second area,
83 Third area,
84 4th area,
85 Catheter stiffness changing part,
90 liver,
100 catheter assembly,
110 catheter hub,
111 Main body,
112 handle part,
113 Male thread part,
120 guide wire hub,
121 Main body,
122 ring part,
200 measurement test equipment,
201 Fixing jig,
202 push-down jig,
203 support leg,
204 Groove,
205 Measurement object (single guide wire, single catheter, catheter assembly),

Claims (4)

a catheter having a shaft portion having a lumen;
a catheter hub attached to the proximal end of the catheter;
a guide wire having a flexible core wire and capable of being inserted into the inner cavity of the shaft portion;
a guidewire hub attached to the proximal end of the guidewire and detachably connected to the catheter hub;
The guidewire has a guidewire stiffness changing portion whose stiffness gradually decreases from the proximal side to the distal side,
The catheter has a catheter stiffness changing portion whose stiffness gradually decreases from the proximal end to the distal end,
With the catheter hub and the guidewire hub connected,
A catheter assembly in which the difference between adjacent bending load values every 50 mm within 400 mm from the tip is 20 gf or less. The catheter assembly according to claim 1, wherein the bending load value in the catheter stiffness changing section increases stepwise from the distal end to the proximal end. The core wire is
a tip core portion that is the most flexible of the entire length of the core wire, including the tip end;
a main body portion that forms a base end side of the distal core portion and has a constant diameter along the axial direction;
the guidewire stiffness changing portion, which constitutes a portion from the distal end of the main body portion to the proximal end of the distal core portion, and whose rigidity gradually decreases from the main body portion toward the distal core portion;
The core wire is supported at two points with a spacing of 25.4 mm, and the supported central portion is vertically pushed down by 2 mm using a push-down jig that moves at a speed of 5 mm/min. The bending load value y of the catheter assembly to be calculated is, when the length from the tip of the core wire is x,
The catheter assembly according to claim ¹ or 2, wherein the catheter assembly is expressed by the approximate formula: y=0.0000070x 3 -0.0016696x ² +0.3726389x+8.3177570. a catheter having a shaft portion having a lumen;
a catheter hub attached to the proximal end of the catheter;
a guide wire having a flexible core wire and capable of being inserted into the inner cavity of the shaft portion;
a guidewire hub attached to the proximal end of the guidewire and detachably connected to the catheter hub;
The guidewire has a guidewire stiffness changing portion whose stiffness gradually decreases from the proximal side to the distal side,
The catheter has a catheter stiffness changing portion whose stiffness gradually decreases from the proximal end to the distal end,
With the catheter hub and the guidewire hub connected,
Among the bending load values adjacent every 50 mm within 400 mm from the distal end, the bending load value on the distal end side is 50% or more of the bending load value on the proximal end side.