Catheter assembly and catheter

Abstract

To provide a catheter assembly suitably having pushability.SOLUTION: The flexural load value y of the guide wire is expressed by an approximate expression of second or higher order of x when the length from the distal end of the guide wire is x, and when the guide wire is inserted into the lumen of the catheter and the guide wire is protruded from the distal end opening of the catheter, the flexural load value of the catheter is smaller than the flexural load value of the guide wire.SELECTED DRAWING: Figure 9

Description

[Technical Field]

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

[0002] Catheter devices have been used for performing treatments and the like within biological lumens. A guidewire having a flexible core wire is used to guide the catheter device to the target site in the biological lumen. For example, trans-arterial chemoembolization (TACE) is a treatment method in which a catheter is advanced from the hepatic artery to the vicinity of a tumor, and an anti-cancer agent or an embolic substance is injected to selectively necrotize the tumor. In this trans-arterial chemoembolization, a guidewire is used to advance the catheter.

[0003] A common technique for guiding a catheter to a target site is to advance the catheter while following a guidewire that has been placed ahead of it.Furthermore, a technique is also common in which an integrated catheter assembly is used in which the guidewire is inserted into the catheter, and both the guidewire and the catheter are advanced together.

[0004] The integrated 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 detachably connected to the catheter hub. The catheter hub and guidewire hub are connected together with a predetermined area of ​​the guidewire exposed from the distal end of the catheter.

[0005] Biological lumens have complex curved or meandering shapes. To improve operability when passing a guidewire through a biological lumen, a guidewire with a variable stiffness section whose stiffness gradually decreases from the proximal end to the distal end is known. The stiffness of the variable stiffness section is changed by gradually reducing the diameter of the core wire.

[0006] When a guidewire having a variable rigidity portion is applied to an integrated catheter assembly, simply connecting the guidewire and catheter may cause discomfort to the surgeon. For example, if the catheter has a relatively high rigidity, the rigidity changes (increases) suddenly from the distal end to the proximal end at the catheter tip, which is the starting point where the guidewire is exposed. This results in impaired operability of the integrated catheter assembly, despite the use of a flexible guidewire.

[0007] In this regard, for example, Patent Document 1 listed below discloses a catheter assembly that can reduce discomfort in use and improve operability. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2018 / 181178 Summary of the Invention [Problem to be solved by the invention]

[0009] As a result of thorough investigation of the above-mentioned prior art documents, the present inventors have found that in the catheter assembly disclosed in Patent Document 1, as shown in FIG. 3A of Patent Document 1, the bending load value of the integrated catheter and guidewire increases significantly, for example, by approximately 35 gf in the range of 300 mm to 360 mm from the tip, and this may result in insufficient pushability for efficiently transmitting a pushing force to the tip side.

[0010] The present invention is intended to solve the above problems, and has an object to provide a catheter assembly that is preferably provided with pushability. [Means for solving the problem]

[0011] The above object of the present invention can be achieved by the following means.

[0012] (1) A catheter assembly comprising a catheter and a guidewire, The guide wire is supported at two points spaced 5 mm apart, and the supported central part is vertically pressed down 0.3 mm with a pressing jig moving at a speed of 5 mm / min to measure the load. The bending load value y of the guide wire obtained by measuring the load at the time when the supported central part is pressed down 0.3 mm vertically is expressed by an approximation equation of x of second degree or higher, where x is the length from the tip of the guide wire, When the guide wire is inserted into the lumen of the catheter and protrudes from the distal end opening of the catheter, or when the distal end opening of the catheter and the distal end of the guide wire are aligned, A catheter assembly in which the catheter is supported at two points spaced 5 mm apart, and the load measured when the supported central part is pressed down vertically 0.3 mm using a pressing jig moving at a speed of 5 mm / min, results in a bending load value of the catheter that is smaller than the bending load value of the guide wire.

[0013] (2) When the guidewire is inserted into the lumen of the catheter and protrudes from the distal end opening of the catheter by 20 mm or more, The catheter assembly according to (1), wherein the bending load value of the catheter is smaller than the bending load value of the guide wire.

[0014] (3) A catheter assembly according to (1) or (2), wherein y is expressed by a third-order approximation of x.

[0015] (4) y=0.000002x 3 -0.0003x 2 The catheter assembly described in (3) is expressed by the approximate formula +0.3242x-0.2677.

[0016] (5) The catheter includes, in order from the tip, a tip portion, a first intermediate portion, a second intermediate portion, and a base portion; The bending load value of the tip portion is 30 gf or less, The bending load value of the first intermediate portion is 50 gf or less, The bending load value of the second intermediate portion is 80 gf or less, The catheter assembly according to any one of (1) to (4), wherein the bending load value of the base portion is 140 gf or less. [Effects of the Invention]

[0017] With the catheter assembly configured as described above, the bending load value of the guidewire can be expressed by an approximation equation of the length x that is quadratic or higher. Furthermore, when the guidewire is inserted into the lumen of the catheter and protrudes from the distal-end opening of the catheter, or when the distal-end opening of the catheter and the distal end of the guidewire are aligned, the catheter is supported at two points 5 mm apart, and the supported central part is pushed down vertically by 0.3 mm with a push-down jig that moves at a speed of 5 mm / min. The bending load value of the catheter obtained by measuring the load at this point is smaller than the bending load value of the guidewire. Therefore, it is possible to provide a catheter assembly with favorable pushability, with smooth changes in the bending load value. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing an integrally structured catheter assembly according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram showing the catheter assembly with the catheter hub and guidewire hub disconnected. [Figure 3] FIG. 2 is an enlarged axial cross-sectional view of the distal end portion of the catheter assembly. [Figure 4] FIG. 2 is an axial cross-sectional view of the guidewire. [Figure 5]FIG. 2 is an enlarged axial cross-sectional view of the distal end portion of the guide wire. [Figure 6] FIG. 10 is a schematic diagram showing the advancement of an integrated catheter assembly during transcatheter arterial chemoembolization. [Figure 7] 10 is a graph showing bending load values ​​of the catheter alone and the guidewire alone along the axial position of the guidewire when the tip opening of the catheter and the tip of the guidewire are aligned. [Figure 8] 10 is a graph showing bending load values ​​of a catheter assembly along the axial position of the guidewire when the guidewire protrudes 20 mm, 50 mm, and 100 mm from the distal end opening of the catheter. [Figure 9] 1 is a graph showing bending load values ​​of a catheter and a guidewire along the axial position of the guidewire when the guidewire protrudes 20 mm from the distal end opening of the catheter. [Figure 10] FIG. 1 is a cross-sectional view showing a schematic configuration of a measurement test device for measuring bending load values. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope or meaning of terms described in the claims. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0020] The configuration of a catheter assembly 100 according to this embodiment will be described with reference to Figures 1 to 6. Figure 1 is a schematic diagram showing an integrated catheter assembly 100 according to this embodiment. Figure 2 is a schematic diagram showing the catheter assembly 100 with the catheter hub 110 and the guidewire hub 120 disconnected. Figure 3 is an axial cross-sectional view showing an enlarged view of the distal end portion of the catheter assembly 100. Figure 4 is an axial cross-sectional view of the guidewire 10. Figure 5 is an axial cross-sectional view showing an enlarged view of the distal end portion of the guidewire 10. Figure 6 is a schematic view showing a catheter 60 being advanced along the guidewire 10 during hepatic arterial chemoembolization.

[0021] In the description herein, the longitudinal direction (left-right direction in FIG. 1A) in which the shaft portion 70 of the catheter 60 and the core wire 20 of the guidewire 10 extend is defined as the axial direction, indicated by arrow X in each drawing. The direction perpendicular to the axial direction is defined as the radial direction, indicated by arrow R in FIGS. 3 and 5. The side of the catheter assembly 100 that is inserted into a living body (inside a blood vessel) is defined as the tip side (distal side, left side in FIG. 1A) and indicated by arrow X1 in each drawing. The side opposite the tip side that is operated by the hand is defined as the base side (proximal side, right side in FIG. 1A) and indicated by arrow X2 in each drawing. In this specification, the tip portion refers to a portion that includes a certain range in the axial direction from the tip (most distal end), and the base portion refers to a portion that includes a certain range in the axial direction from the base end (extremely proximal end).

[0022] 1 to 5, the catheter assembly 100 comprises a catheter 60 having a shaft portion 70 with a lumen 71, a catheter hub 110 attached to the proximal end of the catheter 60, a guidewire 10 having a flexible core wire 20 and insertable into the lumen 71 of the shaft portion 70, and a guidewire hub 120 attached to the proximal end of the guidewire 10 and detachably connected to the catheter hub 110. The guidewire 10 has a guidewire stiffness varying section 35 whose stiffness gradually decreases from the proximal end to the distal end. The catheter 60 has a catheter stiffness varying section 85 whose stiffness gradually decreases from the proximal end to the distal end.

[0023] The integrated catheter assembly 100 is inserted into a body lumen and is used to guide both the guide wire 10 and the catheter 60 together to a target site in the body lumen.

[0024] For example, as shown in Fig. 6, transarterial chemoembolization (TACE) is a treatment method in which a catheter 60 is advanced from an artery 91 in a liver 90 to the vicinity of a tumor 92, and an anticancer drug or an embolic substance is injected to selectively necrotize the tumor. In this transarterial chemoembolization, an integrated catheter assembly 100 is used.

[0025] A body lumen has a complexly curved or meandering shape, and therefore, when the catheter assembly 100 passes through the body lumen, it needs to have pushability that can efficiently transmit a pushing force to the distal end.

[0026] The configuration of each part will be described in detail below.

[0027] (catheter 60) 1, the catheter 60 has a substantially circular cross section and 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. The catheter 60 has a 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 have the kink protector 115.

[0028] As shown in Fig. 3, the shaft portion 70 is configured as a flexible tubular member having an inner lumen 71 extending in the axial direction. The preferred length of the shaft portion 70 varies depending on the location, thickness, and other aspects of the blood vessel to which it is applied, but is set to, for example, about 700 mm to 2000 mm, and preferably about 1000 mm to 1500 mm. The preferred outer diameter (thickness) of the shaft portion 70 varies depending on the location, thickness, and other aspects of the blood vessel to which it is applied, but is set to, for example, about 0.4 mm to 3.0 mm, preferably about 0.5 mm to 1.1 mm, and more preferably about 0.85 mm to 0.91 mm. The inner diameter of the shaft portion 70 (outer diameter of the lumen 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, etc., but is set, for example, to approximately 0.3 mm to 2.3 mm, preferably approximately 0.4 mm to 0.8 mm, and more preferably approximately 0.68 mm to 0.72 mm.

[0029] As shown in Fig. 3, the shaft portion 70 has a tubular inner layer 72 and an outer layer 73 arranged to cover the outer surface of the inner layer 72. A contrast portion 74 made of a radiopaque material is arranged between the inner layer 72 and the outer layer 73 in a part of the distal end of the shaft portion 70. In the catheter 60 according to this embodiment, the bending load value changes smoothly, so there is no need to provide a distal tip to add flexibility to the distal end of the shaft portion 70. The shaft portion 70 has a reinforcing member 75 formed by braiding wire material on the proximal side of the part where the contrast portion 74 is formed.

[0030] The inner layer 72 is formed from a material softer than the guidewire 10 described below. Examples of suitable materials include fluorine-containing ethylenic polymers such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and ETFE (ethylene-tetrafluoroethylene copolymer), polyamides such as nylon, and polyamide elastomers such as nylon elastomers. Among these, PTFE (polytetrafluoroethylene) or PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), which have high lubricity, are preferred. The use of these materials reduces the frictional resistance of the inner surface, thereby improving the operability of the guidewire 10 inserted into the lumen 71 of the shaft portion 70 during use of the catheter 60. The PTFE (polytetrafluoroethylene) used should have no endothermic peak at 370°C during the temperature rise process in differential scanning calorimetry (DSC) and a tensile strength of 350% or greater.

[0031] Examples of materials constituting the outer layer 73 include polymer 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, polyester elastomer, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, and fluorine-based resin, or mixtures thereof. The outer layer 73 may have a multilayer structure formed by laminating different resin materials. It is also possible to form a hydrophilic coating layer by coating the outer surface of the outer layer 73 with a material made of a hydrophilic polymer.

[0032] The contrast portion 74 is made of a metal material or resin material that has higher radiopacity 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 of these. The radiopaque resin material can be made by coating or incorporating an X-ray contrast substance into a resin material that is not radiopaque. Examples of the X-ray contrast substance include powdered inorganic materials such as tungsten, barium sulfate, and bismuth oxide.

[0033] The catheter hub 110 is liquid-tightly attached to the proximal end of the shaft portion 70 by adhesive, a fixing device (not shown), or the like. As shown in FIG. 1 , the catheter hub 110 has 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 guidewire 10 into the inner cavity 71 of the shaft portion 70, an injection port for contrast medium, medicinal liquid, embolic material, etc. The catheter hub 110 functions as a grip portion when operating the catheter 60. A male thread portion 113 is formed at the proximal end of the main body portion 111.

[0034] Examples of materials that can be used to form the catheter hub 110 include synthetic resins such as polycarbonate, polyolefin, styrene-based resin, polyamide, and polyester, stainless steel, aluminum, and aluminum alloy. Examples of polyolefins include polyethylene, polypropylene, and ethylene-propylene copolymer.

[0035] The anti-kink protector 115 can be made of an elastic material and provided so as to surround a part of the base end of the shaft portion 70. Examples of materials that can be used to form the anti-kink protector 115 include natural rubber and silicone resin.

[0036] As shown in Fig. 1, the catheter 60 has a catheter stiffness varying section 85 whose stiffness gradually decreases from the base end to the tip end. As shown in Fig. 7, the bending load value in the catheter stiffness varying section 85 increases in a stepwise manner from the tip end to the base end.

[0037] In this embodiment, the catheter stiffness varying section 85 gradually decreases the stiffness of the shaft section 70 of the catheter 60 from the base end side toward the tip end side. As shown in Fig. 1, the catheter stiffness varying section 85 is divided into four regions, in order from the base end side toward the tip end side of the shaft section 70: a base section 81, a second intermediate section 82, a first intermediate section 83, and a tip section 84. The base region 80, which is continuous with the base end of the base section 81, has a constant stiffness along the axial direction.

[0038] In FIG. 7, the base portion 81 is designated by reference numeral 81a, the second intermediate portion 82 is designated by reference numeral 82a, the first intermediate portion 83 is designated by reference numeral 83a, and the tip portion 84 is designated by reference numeral 84a.

[0039] The catheter stiffness varying section 85 can be formed, for example, by arranging multiple materials with different hardnesses along the axial direction. In this embodiment, the outer layer 73 of the shaft section 70 has multiple regions with different hardnesses along the axial direction, and the hardness of the material constituting each region decreases toward the distal end (flexibility increases toward the distal end). The hardness of the material constituting the outer layer 73 in the distal section 84 is lower than the hardness of the material constituting the outer layer 73 in the first intermediate section 83. The hardness of the material constituting the outer layer 73 in the first intermediate section 83 is lower than the hardness of the material constituting the outer layer 73 in the second intermediate section 82. The hardness of the material constituting the outer layer 73 in the second intermediate section 82 is lower than the hardness of the material constituting the outer layer 73 in the base section 81. The hardness of the material constituting the outer layer 73 in the base section 81 is lower than the hardness of the material constituting the outer layer 73 in the base region 80. As a result, the shaft portion 70 of the catheter 60 is configured such that the tip portion 84 is more flexible than the first intermediate portion 83, the first intermediate portion 83 is more flexible than the second intermediate portion 82, the second intermediate portion 82 is more flexible than the base portion 81, and the base portion 81 is more flexible than the base region 80.

[0040] Examples of the hardness of the constituent materials are as follows. The hardness is a value measured using a Type D durometer conforming to ASTM D2240. The distal end portion 84 is located at the distal end of the catheter 60 and is therefore the most flexible. The hardness of the constituent material thereof is preferably 20D to 40D, more preferably 25D to 35D. The first intermediate portion 83 is the second most flexible after the distal end portion 84 and is preferably 25D to 60D, more preferably 30D to 40D. The second intermediate portion 82 is the second most flexible after the first intermediate portion 83 and is preferably 25D to 60D, more preferably 30D to 40D. The base portion 81 requires an appropriate hardness to transmit the surgeon's operation from the proximal end side to the distal end side. The hardness of the constituent material thereof is preferably 40D to 80D, more preferably 60D to 70D. The base region 80 must have sufficient hardness to be directly manipulated by the surgeon, and the hardness of the material that constitutes it is preferably 50D to 90D, and more preferably 70D to 80D.

[0041] As shown in Fig. 7, the bending load value of the tip portion 84 is preferably 30 gf or less. The bending load value of the first intermediate portion 83 is preferably 50 gf or less. The bending load value of the second intermediate portion 82 is preferably 80 gf or less. The bending load value of the base portion 81 is preferably 140 gf or less. The method for measuring the bending load value will be described later.

[0042] To achieve these hardnesses, the outer layer 73 is made of the above-mentioned materials, but a combination of these materials may also be used. To adjust the hardness within an optimal range, additives may be added to the materials. The thickness of the outer layer 73 can also be changed to adjust the hardness.

[0043] The preferred axial length of each region in the catheter stiffness change section 85 varies depending on the configuration of the guidewire stiffness change section 35 in the guidewire 10 inserted into and connected to the catheter 60 (such as the number of regions and the axial length of each region). The preferred axial length of each region in the catheter stiffness change section 85 also varies depending on the dimension of the distal end side of the guidewire 10 exposed from the distal end of the shaft section 70. For example, the axial length of the base section 81 is 50 mm, the axial length of the second intermediate section 82 is 150 mm, the axial length of the first intermediate section 83 is 150 mm, and the axial length of the distal section 84 is 100 mm. The axial length of the base region 80 varies depending on the product length.

[0044] The thickness of the inner layer 72 in the shaft portion 70 is constant over the entire axial length. The thickness of the inner layer 72 is not particularly limited, but is, for example, 0.015 mm.

[0045] (Guidewire 10) 1, 4, and 5, the guidewire 10 includes a core wire 20 extending in the axial direction and a guidewire hub 120 connected to the proximal end of the core wire 20. The guidewire 10 also includes a marker portion 40 disposed at the distal end of the core wire 20 and a coating layer 50 that coats the core wire 20.

[0046] The preferred length of the guidewire 10 varies depending on the location, thickness, etc. of the blood vessel to which it is applied, but is preferably 500 to 4000 mm, for example. The preferred outer diameter (thickness) of the main body 30 varies depending on the location, thickness, etc. of the blood vessel to which it is applied, but is preferably 0.15 to 2.0 mm, for example.

[0047] As shown in FIG. 2 , the proximal end of the guidewire 10 is attached to the wall of the distal end of the guidewire hub 120. The guidewire hub 120 has a main body 121 having an internal cavity and a ring 122 disposed on the distal side of the main body 121. The proximal end of the guidewire 10 is inserted into the main body 121 during injection molding. 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 internal cavity 71 of the shaft 70. Liquid can be injected or withdrawn while the guidewire 10 remains inserted in the internal cavity 71 of the shaft 70. The ring 122 has an internal thread (not shown) formed on its inner circumferential surface that screws into the external thread 113 of the catheter hub 110. The ring 122 can rotate relative to the main body 121, but is prevented from slipping out of the main body 121 in the distal direction by engaging with a protrusion (not shown) formed on the outer periphery of the main body 121.

[0048] 1, the tip of guidewire hub 120 is fitted into the lumen of catheter hub 110, and ring portion 122 is rotated to screw male thread portion 113 into female thread portion and then tightened with a certain amount of torque. This connects catheter hub 110 and guidewire hub 120 in a liquid-tight manner, and this connected state is maintained. The male thread portion 113 and ring portion 122 having a female thread portion constitute a locking means that fixes the connected state of catheter hub 110 and guidewire hub 120.

[0049] The guidewire hub 120 is made of a synthetic resin such as polycarbonate, polyolefin, styrene-based resin, polyamide, polyester, etc. Examples of polyolefin include polyethylene, polypropylene, and ethylene-propylene copolymer.

[0050] 5, the marker portion 40 is arranged so as to cover a certain range of the distal core portion 34 in the axial direction. The marker portion 40 is composed of a wire wound spirally around the distal core portion 34. The distal end of the marker portion 40 is fixed near the distal end of the distal core portion 34 via a fixing material 41. The base end of the marker portion 40 is fixed near the base end of the distal core portion 34 via a fixing material 42. The fixing materials 41 and 42 can be composed of, for example, various adhesives, solder, etc.

[0051] The marker portion 40 is made of a material that is opaque to radiography (radiographically opaque). Examples of materials that are opaque to radiography include metallic materials such as precious metals such as gold, platinum, and tungsten, and alloys containing these metals (e.g., platinum-iridium alloys). By providing the marker portion 40 on the distal core portion 34, the position of the distal end of the guidewire 10 can be confirmed under X-ray fluoroscopy while the guidewire 10 is inserted into a living body.

[0052] The covering layer 50 is made of a resin material and is formed so as to cover the entire core wire 20 including the marker portion 40. The distal end of the covering layer 50 preferably has a rounded shape so as not to damage the inner wall of the biological lumen.

[0053] The covering layer 50 is preferably made of a material that can reduce friction. This reduces the frictional resistance (sliding resistance) between the guidewire 10 and the catheter 60 through which the guidewire 10 is inserted or the biological lumen, improving the slidability and improving the operability of the guidewire 10. Furthermore, the reduced sliding resistance of the guidewire 10 more reliably prevents kinking (bending) and twisting of the guidewire 10.

[0054] The resin material constituting the coating layer 50 is preferably a relatively flexible material, such as polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyesters (PET, PBT, etc.), polyamides, polyimides, polyurethanes, polystyrene, polycarbonates, silicone resins, fluorine-based resins (PTFE, ETFE, PFA, etc.), composites of these, various rubber materials such as latex rubber and silicone rubber, or composites of two or more of these. Among the above materials, urethane resins are more preferred from the viewpoint of further improving flexibility. This allows the distal end of the guidewire 10 to be flexible, thereby preventing damage to the inner wall of a biological lumen when the guidewire 10 is inserted into the biological lumen.

[0055] The thickness of the coating layer 50 is not particularly limited, but is preferably 5 to 500 μm, for example. The coating layer 50 is not limited to a single-layer structure, and may be configured by laminating multiple layers.

[0056] The coating layer 50 is preferably covered with a hydrophilic coating layer (not shown). Covering with a hydrophilic coating layer improves slidability, thereby further preventing the guidewire 10 from getting caught on the inner wall of the biological lumen or the catheter 60.

[0057] The constituent material of the hydrophilic coating layer is not particularly limited, and examples thereof include known hydrophilic materials such as cellulose-based polymeric substances, polyethylene oxide-based polymeric substances, maleic anhydride-based polymeric substances (e.g., maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymer), acrylamide-based polymeric substances (e.g., polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA) block copolymer), water-soluble nylon, polyvinyl alcohol, and polyvinylpyrrolidone.

[0058] The thickness of the hydrophilic coating layer is not particularly limited, but is preferably, for example, 0.1 to 100 μm.

[0059] As shown in FIG. 4, the guidewire 10 has a guidewire rigidity varying section 35 whose rigidity gradually decreases from the proximal end side toward the distal end side.

[0060] In this embodiment, the guidewire stiffness varying section 35 gradually decreases the stiffness of the core wire 20 from the proximal end side toward the distal end side. The main body section 30 has a constant stiffness along the axial direction.

[0061] The guidewire stiffness varying section 35 can be configured, for example, by varying the diameter of the core wire 20 along the axial direction. The guidewire stiffness varying section 35 has a diameter d5 that gradually decreases from the main body section 30 toward the distal core section 34.

[0062] 7 is a graph showing bending load values ​​of the core wire 20 of the guidewire 10 along the axial position of the core wire 20. Note that the coating layer 50 that covers the core wire 20 does not substantially contribute to the stiffness of the guidewire 10. Therefore, the stiffness of the core wire 20 can be considered to be the stiffness of the guidewire 10, and the guidewire stiffness change portion 35 also represents a stiffness change portion of the core wire 20.

[0063] The core wire 20 is flexible. As shown in Figures 4 and 5, the core wire 20 has a distal core section 34, a main body section 30, and a guidewire stiffness varying section 35. The distal core section 34 is the most flexible section of the entire length of the core wire 20, including the most distal end. The main body section 30 is located on the proximal side of the distal core section 34 and has a constant diameter d0 along the axial direction. The guidewire stiffness varying section 35 extends from the distal end of the main body section 30 to the proximal end of the distal core section 34, and has a section in which stiffness gradually decreases from the main body section 30 toward the distal core section 34.

[0064] In this embodiment, the core wire 20 is made of a single material. The diameter of the core wire 20 varies along the axial direction, which causes the stiffness of the core wire 20 to vary along the axial direction.

[0065] The material of the core wire 20 is not particularly limited, but may be, for example, a Ni-Ti alloy, stainless steel, or a superelastic alloy.

[0066] 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.

[0067] In this specification, "having a constant diameter along the axial direction" does not mean that the diameter is physically the same. It is sufficient that the outer diameter is approximately constant within a range that allows the rigidity (bending rigidity and torsional rigidity) of the main body portion 30 and the tip core portion 34 to be approximately constant.

[0068] The guidewire stiffness varying section 35 can be configured, for example, by varying the diameter of the core wire 20 along the axial direction. The guidewire stiffness varying section 35 has a diameter d5 that gradually decreases from the main body section 30 toward the distal core section 34.

[0069] In this embodiment, the range of the changed rigidity portion in the core wire is up to 500 mm from the tip of the core wire, but is not limited to this.

[0070] The core wire disclosed in WO 2018 / 181177 A1 has, in order from the proximal end, a first tapered section, a second tapered section, and a third tapered section, and is configured so that the gradient of the diameter change in the first tapered section is greater than the gradient of the diameter change in the second tapered section. Therefore, as shown in Figure 3B of WO 2018 / 181177 A1, a bending point where the gradient of the diameter bends and changes occurs at the boundary between the first tapered section and the second tapered section.

[0071] In contrast, in the guidewire stiffness varying portion 35 according to this embodiment, as shown in Fig. 7, it can be seen that the bending load value y increases as the distance x from the tip of the guidewire 10 according to this embodiment increases. In this embodiment, the bending load value y can be expressed by an approximation equation of the distance x that is quadratic or higher.

[0072] The inventors calculated an approximate expression corresponding to the correlation between the distance x from the tip of the guidewire 10 and the bending load value y in the guidewire stiffness varying portion 35. As a result, the following approximate expression was calculated.

[0073] The following approximate formula was calculated as the second-order approximation formula: y=0.0008x 2 +0.1515x+5.9275 The following approximation formula was calculated as a third-order approximation formula: y=0.000002x 3 -0.0003x 2 +0.3242x-0.2677 The following approximation formula was calculated as the fourth-order approximation formula: y=0.000000006x 4 -0.000002x 3 +0.0007x 2 +0.2304x+1.9435

[0074] The bending load value of one guide wire 10 has been described above as an example, but as long as the bending load value y can be expressed by an approximation equation of the distance x of second degree or higher, it is not limited to the guide wire 10 expressed by the above approximation equation.

[0075] With the guidewire 10 configured as described above, the bending load value increases with increasing distance from the tip of the core wire 20, thereby improving pushability. Furthermore, with the guidewire 10 configured as described above, the bending load value y is expressed by a quadratic or higher approximation equation, where x is the length from the tip of the core wire. This causes the diameter of the core wire to change continuously, and no boundary is formed, as in the guidewire disclosed in the comparative example. This improves pushability. From the above, it is possible to provide a guidewire 10 that exhibits favorable pushability.

[0076] In order to form a continuous boundary between the main body 30 and the guidewire stiffness variable section 35, the diameter d5 of the proximal end of the guidewire stiffness variable section 35 is approximately the same as the diameter d0 of the main body 30. Similarly, the diameter d5 of the distal end of the guidewire stiffness variable section 35 is approximately the same as the diameter d4 of the distal core section 34.

[0077] As used herein, the term "continuous surface" means that the outer surface of the core wire 20 is smooth enough to prevent the guidewire 10 from getting caught on the inner wall of a biological lumen or the catheter 60. For example, if the diameter d5 of the proximal end of the guidewire stiffness variable section 35 and the diameter d0 of the main body section 30 are not substantially the same, a slight step will occur at the boundary between the guidewire stiffness variable section 35 and the main body section 30. However, the coating layer 50 may make the outer surface of the guidewire 10 substantially smooth, preventing the guidewire 10 from getting caught on the inner wall of a biological lumen or the like. In such cases, even if a slight step occurs on the core wire 20, the outer surface of the core wire 20 can be considered to be a "continuous surface."

[0078] The core wire 20 is formed by subjecting a forming material to cutting and polishing processes. The main body portion 30, the guidewire stiffness varying portion 35, and the distal core portion 34 can be formed simultaneously. Alternatively, each region can be formed separately and sequentially. The manufacturing method of the core wire 20 is not limited to cutting and polishing processes, and it can also be formed by etching or laser processing.

[0079] Next, with reference to Figures 8 and 9, the relationship between the bending load value of the catheter assembly 100, the bending load value of the catheter 60, and the bending load value of the guidewire 10 when the guidewire 10 protrudes from the distal opening of the catheter 60 will be described. Figure 8 is a graph showing the bending load values ​​of the catheter assembly 100 along the axial position of the guidewire 10 when the guidewire 10 protrudes 20 mm, 50 mm, and 100 mm from the distal opening of the catheter 60. Figure 9 is a graph showing the bending load values ​​of the catheter 60 and the guidewire 10 along the axial position of the guidewire 10 when the guidewire 10 protrudes 20 mm from the distal opening of the catheter 60.

[0080] 8, it can be seen that the bending load value of the catheter assembly 100 increases when the length by which the guidewire 10 protrudes from the distal end opening of the catheter 60 is changed to 20 mm, 50 mm, and 100 mm. In other words, by increasing the protruding length of the guidewire 10, the stiffness of the catheter assembly 100 can be improved. Therefore, the protruding length of the guidewire 10 can be appropriately changed during the procedure depending on the symptoms and treatment location.

[0081] Furthermore, as shown in FIG. 9, when the guidewire 10 protrudes 20 mm from the distal end opening of the catheter 60, the bending load value of the guidewire 10 is higher than the bending load value of the catheter 60 throughout the entire area. Here, for example, if the bending load value of the guidewire is lower than the bending load value of the catheter, an increased portion M, where the bending load value of the catheter assembly is locally increased, will occur, as shown in the comparative example of FIG. 8. The occurrence of such an increased portion M makes the catheter assembly more susceptible to kinking, reducing operability. In contrast, in the catheter assembly 100 according to the present embodiment, when the guidewire 10 protrudes 20 mm from the distal end opening of the catheter 60, the bending load value of the guidewire 10 is higher than the bending load value of the catheter 60, so no increased portion will occur and reduction in operability can be prevented.

[0082] Next, a method for measuring the bending load value will be described with reference to FIG.

[0083] FIG. 10 is a cross-sectional view showing a schematic configuration of a measurement test device 200 for measuring bending load values.

[0084] 10, measurement test device 200 has a fixing jig 201 that supports a long measurement object 205, and a push-down jig 202 that is arranged above fixing jig 201. Fixing jig 201 has a pair of support legs 203 that support measurement object 205 at two points. The distance Ld between support legs 203 is 5 mm. A groove 204 into which measurement object 205 fits is formed on the upper surface of support leg 203. Push-down jig 202 is configured to be able to move up and down freely relative to fixing jig 201. Push-down jig 202 is configured to be able to freely adjust the speed at which it pushes down measurement object 205 and the size by which it pushes down measurement object 205.

[0085] The measurement object 205 is the guide wire 10, the shaft portion 70 of the catheter 60, and the catheter assembly 100 in which the catheter 60 and the guide wire 10 are connected.

[0086] In this embodiment, the bending load value was measured and obtained using the measurement test device 200 under the following conditions: The measurement object 205 was supported at two points spaced 5 mm apart. The push-down jig 202 moved at a speed of 5 mm / min. The supported central portion of the measurement object 205 was pressed down vertically by the push-down jig 202. The bending load value was measured as the load when the measurement object 205 was pressed down 0.3 mm.

[0087] In this embodiment, the axial length of the core wire 20 is a length used for hepatic artery chemoembolization. In this case, the axial length L of the guidewire rigidity variable section 35 is preferably 360 to 450 mm, and more preferably 360 to 400 mm. By using a guidewire rigidity variable section 35 with this length L, the region of the core wire 20 that extends from the aorta to the common hepatic artery (300 to 400 mm from the tip) becomes flexible, making it possible to perform hepatic artery chemoembolization in an appropriate manner.

[0088] As described above, the catheter assembly 100 according to this embodiment is a catheter assembly 100 including a catheter 60 and a guidewire 10. The bending load value y of the guidewire 10 obtained by measuring the load when the guidewire 10 is supported at two points spaced 5 mm apart and the supported central portion is pressed down vertically by 0.3 mm with a pressing jig that moves at a speed of 5 mm / min is smaller than the bending load value of the guidewire 10, where x is the length of the guidewire 10 from the tip. According to the catheter assembly 100 configured in this manner, it is possible to provide a catheter assembly 100 that can smoothly change the bending load value and has favorable pushability.

[0089] The catheter assembly 100 according to the present invention has been described above through an embodiment, but the present invention is not limited to the configurations described in the specification and can be modified as appropriate based on the description of the claims.

[0090] For example, although the catheter assembly 100 used in hepatic arterial chemoembolization has been given as an example, it goes without saying that the catheter assembly 100 of the present invention can be used in other procedures. The catheter 60 and the guidewire 10 each may have an appropriate length depending on the procedure to be applied.

[0091] Although the guidewire 10 has been described as being formed from a single material and having its stiffness varied along the axial direction by varying its diameter (i.e., tapering) along the axial direction, the present invention is not limited to this configuration. The stiffness can be varied along the axial direction by using different materials for the main body section 30, the guidewire stiffness varying section 35, and the distal core section 34. The main body section 30, the guidewire stiffness varying section 35, and the distal core section 34, which are made of different materials, can be joined by any known method, such as welding, melting, or adhesive bonding. The core wire 20 may be formed by combining different materials with a tapered shape.

[0092] Although the catheter 60 has been described as having a configuration in which the stiffness is varied along the axial direction by varying the hardness of the outer layer 73 of the shaft portion 70 along the axial direction, the present invention is not limited to this. The shaft portion 70 can be formed from the same material, but the stiffness can be varied along the axial direction by varying the thickness of the material along the axial direction. For example, the outer layer 73 of the shaft portion 70 can have multiple regions of different thickness along the axial direction, with the thickness of each region decreasing toward the distal end (increasing flexibility toward the distal end). The stiffness of the catheter 60 can be varied by a combination of both the hardness and thickness of the material.

[0093] Furthermore, in the above-described embodiment, when the guidewire 10 is inserted into the lumen of the catheter 60 and protrudes 20 mm or more from the tip opening of the catheter 60, the bending load value of the catheter 60 is smaller than the bending load value of the guidewire 10. However, when the tip opening of the catheter 60 and the tip of the guidewire 10 are aligned, the bending load value of the catheter 60 may be smaller than the bending load value of the guidewire 10.

[0094] Furthermore, in the above-described embodiment, when the guidewire 10 is inserted into the lumen of the catheter 60 and protrudes 20 mm or more from the distal end opening of the catheter 60, the bending load value of the catheter 60 is smaller than the bending load value of the guidewire 10. However, the bending load value of the catheter 60 may be smaller than the bending load value of the guidewire 10 at any protruding length of the guidewire 10. [Explanation of symbols]

[0095] 10 guidewire, 20 core wire, 30 main body, 34 Tip core part, 35 Guidewire stiffness change section, 40 marker section, 50 coating layer, 60 catheters, 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 change part, 90 liver, 100 catheter assembly, 110 catheter hub, 111 main body, 112 Handle part, 113 Male threaded portion, 120 guidewire hub, 121 main body, 122 ring part, 200 measuring test equipment, 201 Fixture, 202 Press-down jig, 203 Support legs, 204 groove, 205 Measurement object (guide wire alone, catheter alone, catheter assembly),

Claims

1. A catheter assembly comprising a catheter and a guidewire, The guide wire is supported at two points spaced 5 mm apart, and the supported central portion is vertically pressed down by 0.3 mm with a pressing jig moving at a speed of 5 mm / min to measure the load. The bending load value y of the guide wire obtained by measuring the bending load value is expressed by a quadratic or higher approximation of x, where x is the length from the tip of the guide wire, When the guide wire is inserted into the lumen of the catheter and protrudes from the distal end opening of the catheter, or when the distal end opening of the catheter and the distal end of the guide wire are aligned, A catheter assembly, wherein the catheter is supported at two points spaced 5 mm apart, and the load measured when the supported central part is pressed down vertically 0.3 mm with a pressing jig moving at a speed of 5 mm / min, results in a bending load value of the catheter that is smaller than the bending load value of the guide wire.

2. When the guidewire is inserted into the lumen of the catheter and protrudes from the distal end opening of the catheter by 20 mm or more, The catheter assembly according to claim 1 , wherein the bending load value of the catheter is less than the bending load value of the guidewire.

3. 3. The catheter assembly according to claim 1, wherein y is expressed by a third-order approximation of x.

4. y=0.000002x ３ -0.0003x ２ 4. The catheter assembly according to claim 3, which is expressed by the approximate formula +0.3242x-0.2677.

5. The catheter includes, in order from the tip, a tip portion, a first intermediate portion, a second intermediate portion, and a base portion; The bending load value of the tip portion is 30 gf or less, The bending load value of the first intermediate portion is 50 gf or less, The bending load value of the second intermediate portion is 80 gf or less, 3. The catheter assembly according to claim 1, wherein the bending load value of the base portion is 140 gf or less.

6. The tip portion has, in order from the tip, a tip portion, a first intermediate portion, a second intermediate portion, and a base portion, The specimen is supported at two points spaced 5 mm apart, and the central part of the supported part is pressed down vertically by 0.3 mm with a pressing jig that moves at a speed of 5 mm / min. The bending load value is measured by measuring the load at that point. When the bending load value is defined as the numerical value obtained by the bending load measurement, The bending load value of the tip portion is 30 gf or less, The bending load value of the first intermediate portion is 50 gf or less, The bending load value of the second intermediate portion is 80 gf or less, A catheter, wherein the bending load value of the base portion is 140 gf or less.

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