Guide wire

Abstract

To provide a guide wire suitably provided with pushability.SOLUTION: The guide wire 10 has the flexible core wire 20, and has the distal core portion 34, the main body portion 30, and the rigidity changing portion 35 whose rigidity gradually decreases from the main body portion 30 toward the distal core portion 34. When the core wire is supported at two points at an interval of 5mm and the length from the distal end of the core wire is x, the flexural load y obtained by measuring the load at the time when the supported central portion is vertically pushed down to 0. 3mm by a push-down jig moving at a speed of 5mm / min is represented by an approximate expression of second or higher order of x.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a guidewire. [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] To improve operability when passing a guidewire through a biological lumen, a guidewire is known that has a variable stiffness section in which the stiffness gradually decreases from the proximal end to the distal end. The stiffness of the variable stiffness section is changed by gradually reducing the diameter of the core wire.

[0004] A biological lumen has a complex curved or meandering shape, and therefore, when a guidewire passes through a biological lumen, the further the distal end of the guidewire reaches, the greater the bending load acting on the core wire.

[0005] In conventional guidewires, the range in which the core wire's rigidity change section is provided is limited to a maximum of 300 mm from the tip of the corewire. Therefore, in procedures in which the target treatment site is located deep within a biological lumen, a large bending load acts on the corewire. A restoring force acts on the bent corewire, causing it to return to its original straight state. As a result, when the guidewire's fixation is released, the guidewire shifts in the direction of slipping out of the body. Thus, unintended displacement of the guidewire can easily occur.

[0006] In order to reduce unintended displacement of the guidewire, it is conceivable to widen the range of the stiffness change portion in the core wire toward the proximal end, but simply widening the range of the stiffness change portion can cause discomfort to the surgeon.

[0007] In this regard, for example, Patent Document 1 listed below discloses a guidewire that can reduce unintended displacement of the guidewire while suppressing discomfort in use. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2018 / 181177A1 Summary of the Invention [Problem to be solved by the invention]

[0009] As shown in FIG. 3A of Patent Document 1, the guidewire disclosed in Patent Document 1 has a low bending load value up to a point approximately 300 mm from the tip, which may result in a lack of pushability that allows for efficient transmission of pushing force toward the tip side.

[0010] Furthermore, in the guidewire disclosed in Patent Document 1, as shown in Figure 3B of Patent Document 1, a boundary portion is formed where the gradient of the diameter of the core wire changes, so when the guidewire is pushed toward the tip, it may bend at the boundary portion, which may result in insufficient pushability.

[0011] The present invention is intended to solve the above problems, and has an object to provide a guidewire that is preferably provided with pushability. [Means for solving the problem]

[0012] The above object of the present invention can be achieved by the following means.

[0013] (1) 1. A guidewire having a flexible core wire, The core wire is a distal core portion that is the most flexible of the entire length of the core wire, including the distal end; a main body portion that is located on the base end side of the distal core portion and has a constant diameter along the axial direction; a rigidity varying portion that constitutes a portion from the tip of the main body portion to the base end of the tip core portion, and whose rigidity gradually decreases from the main body portion toward the tip core portion, The core wire is supported at two points spaced 5 mm apart, and the supported central part is pressed down vertically by 0.3 mm using a pressing jig that moves at a speed of 5 mm / min. The bending load value y obtained by measuring the bending load is, when the length from the tip of the core wire is defined as x, y is a guidewire that is expressed as a quadratic or higher approximation of x.

[0014] (2) The guide wire according to (1), wherein y is expressed by a third-order approximation of x.

[0015] (3) y=0.000002x 3 -0.0003x 2 The guide wire according to (2), which is expressed by the approximate formula +0.3242x-0.2677.

[0016] (4) 0.000004x 3 -0.0011x 2 +0.2743x+0.9843≦y≦0.000008x 3 -0.0046x 2 The guidewire according to any one of (1) to (3), which is expressed by the approximate formula +1.0276x-1.4543.

[0017] (5) The guidewire according to any one of (1) to (4), wherein the variable rigidity portion is provided in a region of the core wire from 20 mm to 500 mm from the tip.

[0018] (6) The guide wire according to any one of (1) to (5), wherein the core wire is formed from a single material. [Effects of the Invention]

[0019] In the guidewire configured as described above, the bending load value y is expressed by a quadratic or higher approximation of x, where x is the length from the tip of the core wire. Therefore, the bending load value increases with increasing distance from the tip. Therefore, rigidity and pushability are improved even in the region up to 300 mm from the tip. Furthermore, in the guidewire configured as described above, the bending load value y is expressed by a quadratic or higher approximation of x, where x is the length from the tip of the core wire. Therefore, the diameter of the core wire changes continuously, and no boundary portion is formed, as in the guidewire disclosed in Patent Document 1. Therefore, pushability is improved. From the above, a guidewire with favorable pushability can be provided. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an axial cross-sectional view of a guidewire according to an embodiment of the present invention. [Figure 2] 2 is an enlarged axial cross-sectional view showing a distal end portion of the guidewire according to the embodiment. FIG. [Figure 3] FIG. 1 is a schematic diagram showing a catheter being advanced along a guidewire in transarterial chemoembolization. [Figure 4] 1 is a graph showing bending load values ​​of a core wire of a guidewire along an axial position of the core wire, showing upper, middle, and lower bending load values. [Figure 5]10 is a graph showing bending load values ​​of a core wire of a guide wire along the axial position of the core wire, the graph showing intermediate values ​​of the bending load values ​​and quadratic approximations of the intermediate values. [Figure 6] 10 is a graph showing bending load values ​​of a core wire of a guide wire along the axial position of the core wire, the graph showing intermediate values ​​of the bending load values ​​and a cubic approximation of the intermediate values. [Figure 7] 10 is a graph showing bending load values ​​of a core wire of a guide wire along the axial position of the core wire, the graph showing intermediate values ​​of the bending load values ​​and a fourth-order approximation of the intermediate values. [Figure 8] 10 is a graph showing bending load values ​​of a core wire of a guide wire along the axial position of the core wire, the graph showing upper values ​​of the bending load values ​​and a cubic approximation of the upper values. [Figure 9] 1 is a graph showing bending load values ​​of a core wire of a guide wire along the axial position of the core wire, and showing a cubic approximation of the upper values ​​of the bending load values. [Figure 10] FIG. 1 is a cross-sectional view showing a schematic configuration of a measurement test device for measuring the bending load value of a core wire of a guide wire. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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.

[0022] First, the configuration of a guidewire 10 according to this embodiment will be described with reference to Figures 1 to 3. Figure 1 is an axial cross-sectional view of the guidewire 10 according to this embodiment. Figure 2 is an axial cross-sectional view showing an enlarged view of the distal end portion of the guidewire 10 according to this embodiment. Figure 3 is a schematic view showing a catheter 60 being advanced along the guidewire 10 in hepatic arterial chemoembolization.

[0023] In the description herein, the longitudinal direction of the core wire 20 of the guidewire 10 (the left-right direction in FIG. 1) 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 FIG. 2. The side of the guidewire 10 that is inserted into a living body (inside a blood vessel) is defined as the tip side (distal side, left side in FIG. 1), indicated by arrow X1 in each drawing, and the side opposite the tip side that is operated by the hand is defined as the base side (proximal side, right side in FIG. 1), indicated by arrow X2 in each drawing. In this specification, the tip portion means a portion that includes a certain range in the axial direction from the tip (most distal end), and the base end portion means a portion that includes a certain range in the axial direction from the base end (most proximal end).

[0024] As shown in Figures 1 and 2, the guide wire 10 of this embodiment has a core wire 20 extending in the axial direction, a marker portion 40 arranged at the tip of the core wire 20, and a coating layer 50 that coats the core wire 20.

[0025] The guidewire 10 is inserted, for example, into a biological lumen. As shown in Fig. 3, the guidewire 10 is inserted into the inner cavity (guidewire lumen) of a therapeutic or diagnostic catheter 60 within the biological lumen. The guidewire 10 is used to guide the catheter 60 to a target site in the biological lumen.

[0026] For example, as shown in Fig. 3, trans-arterial chemoembolization (TACE) is a treatment method in which a catheter 60 is advanced from an artery 91 in a liver 90 to a location close to a tumor 92, and an anti-cancer agent or an embolic substance is injected to selectively necrotize the tumor. In this trans-arterial chemoembolization, a guidewire 10 is used to advance the catheter 60.

[0027] A biological lumen has a complex curved or meandering shape, and therefore, when the guidewire 10 passes through the biological lumen, it needs to have pushability that can efficiently transmit a pushing force to the distal end.

[0028] (Core wire 20) The configuration of the core wire 20 will be described below with reference to Figs. 4 to 9. Fig. 4 is a graph showing the bending load values ​​of the core wire 20 of the guidewire 10 along the axial position of the core wire 20, and is a graph showing upper, middle, and lower values ​​of the bending load values. Fig. 5 is a graph showing the bending load values ​​of the core wire 20 of the guidewire 10 along the axial position of the core wire 20, and is a graph showing the middle value of the bending load values ​​and a quadratic approximation formula of the middle value. Fig. 6 is a graph showing the bending load values ​​of the core wire 20 of the guidewire 10 along the axial position of the core wire 20, and is a graph showing the middle value of the bending load values ​​and a cubic approximation formula of the middle value. Fig. 7 is a graph showing the bending load values ​​of the core wire 20 of the guidewire 10 along the axial position of the core wire 20, and is a graph showing the middle value of the bending load values ​​and a quartic approximation formula of the middle value. Fig. 8 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, and is a graph showing upper values ​​of the bending load values ​​and a cubic approximation of the upper values. Fig. 9 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, and is a graph showing a cubic approximation of the upper values ​​of the bending load values.

[0029] The core wire 20 is flexible. As shown in FIGS. 1 and 2 , the core wire 20 has a distal core portion 34, a main body portion 30, and a rigidity varying portion 35. The distal core portion 34 is the most flexible portion of the entire length of the core wire 20, including the most distal end. The main body portion 30 is located closer to the base end than the distal core portion 34 and has a constant diameter d0 along the axial direction. The rigidity varying portion 35 extends from the distal end of the main body portion 30 to the base end of the distal core portion 34, and has a gradually decreasing rigidity from the main body portion 30 toward the distal core portion 34.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The rigidity varying portion 35 has a diameter d5 that gradually decreases from the main body portion 30 toward the tip core portion 34.

[0035] In this embodiment, the range of the stiffness varying portion 35 is from 20 mm to 500 mm from the tip of the core wire 20, but is not limited to this.

[0036] 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.

[0037] In contrast, in the variable-rigidity portion 35 of the guidewire 10 according to this embodiment, as shown in Fig. 4, it can be seen that the bending load value y increases as the distance x from the tip of the core wire 20 according to this embodiment increases. In this embodiment, the bending load value y can be expressed by a quadratic or higher approximation of the distance x. The bending load value y is also referred to as the test force or load in the drawings.

[0038] As an example, Figure 4 shows bending load values ​​for three types of core wire 20. Of the three graphs, graph G1 located at the top represents the upper value, graph G2 located at the bottom represents the lower value, and graph G3 located between the upper and lower values ​​represents the intermediate value. In this specification, the intermediate value does not mean "exactly halfway" between the upper and lower values, but refers to a numerical value between the upper and lower values. In the graphs of Figure 4, the core wire 20 having the bending load value shown in graph G1 is relatively hard, and the core wire 20 having the bending load value shown in graph G2 is relatively soft.

[0039] The inventors calculated an approximate formula corresponding to the correlation between the distance x from the tip of the core wire 20 and the bending load value y in the rigidity varying portion 35. As a result, the following approximate formula was calculated.

[0040] In the graph G1 showing the upper value, the following approximate formula was calculated as the second-order approximate formula. y=0.0002x 2 +0.2863x+25.131 In the graph G1 showing the upper value, the following approximate formula was calculated as the third-order approximate formula (see FIGS. 8 and 9). y=0.000008x 3 -0.0046x 2 +1.0276x-1.4543 In graph G1 showing the upper value, the following approximate formula was calculated as the fourth-order approximate formula. y=-0.000000009x 4 +0.00002x 3 -0.0063x 2 +1.183x-5.1185

[0041] 8 and 9, in the graph G1 showing the upper value, a convex portion C that is convex upward is provided in the vicinity of 100 mm in the third-order approximation formula (shown by the dotted line in FIG. 8). Note that it is preferable that the location where the convex portion C is provided is 200 mm or less.

[0042] In graph G2 showing the lower value, the following approximate formula was calculated as the second-order approximate formula: y=0.0015x 2 -0.1214x+15.175 In graph G2 showing the lower value, the following approximation formula was calculated as the third-order approximation formula. y=0.000004x 3 -0.0011x 2 +0.2743x+0.9843 In graph G2 showing the lower value, the following approximate formula was calculated as the fourth-order approximate formula: y=0.00000002x 4 -0.00001x 3 +0.003x 2 -0.0936x+9.6545

[0043] In graph G3 showing intermediate values, the following approximate formula was calculated as the second-order approximate formula (see FIG. 5): In FIG. 5, the second-order approximate formula is indicated by a thin line. y=0.0008x 2 +0.1515x+5.9275 In graph G3 showing intermediate values, the following approximation formula was calculated as the third-order approximation formula (see FIG. 6): In FIG. 6, the third-order approximation formula is indicated by a dotted line. y=0.000002x 3 -0.0003x 2 +0.3242x-0.2677 In graph G3 showing intermediate values, the following approximate formula was calculated as the fourth-order approximate formula (see FIG. 7): In FIG. 7, the fourth-order approximate formula is indicated by a thin line. y=0.000000006x 4 -0.000002x 3 +0.0007x 2 +0.2304x+1.9435

[0044] The bending load values ​​of three types of core wire 20 have been described above as an example, but the bending load value y is not limited to the above three types of core wire 20 as long as it is expressed by an approximation equation of the distance x of second order or higher.

[0045] 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 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. Therefore, the diameter of the core wire also changes continuously, and no boundary portion 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.

[0046] In order to make the boundary between the main body portion 30 and the rigidity change portion 35 a continuous surface, the diameter d5 of the base end side of the rigidity change portion 35 is approximately the same as the diameter d0 of the main body portion 30. Similarly, the diameter d5 of the tip end side of the rigidity change portion 35 is approximately the same as the diameter d4 of the tip core portion 34.

[0047] 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 rigidity 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 rigidity 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."

[0048] The core wire 20 is formed by subjecting a forming material to cutting and polishing processes. The main body portion 30, the variable rigidity 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.

[0049] The above-mentioned bending load values ​​are obtained by bending load value measurements, which will be explained below.

[0050] FIG. 10 is a cross-sectional view showing a schematic configuration of a measurement test device 200 for measuring the bending load value of the core wire 20 of the guide wire 10. As shown in FIG.

[0051] As shown in Fig. 10, the measurement test device 200 has a fixing jig 201 that supports the core wire 20, and a push-down jig 202 that is arranged above the fixing jig 201. The fixing jig 201 has a pair of support legs 203 that support the core wire 20 at two points. The distance Ld between the support legs 203 is 5 mm. A groove 204 into which the core wire 20 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 freely relative to the fixing jig 201. The push-down jig 202 is configured to be able to freely adjust the speed at which it pushes down the core wire 20 and the amount by which it pushes down the core wire 20.

[0052] In this embodiment, the bending load value was measured using the measurement test device 200 under the following conditions to obtain the bending load value. Specifically, the core wire 20 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 core wire 20 was pressed down vertically by the push-down jig 202. The bending load value was measured at the point when the core wire 20 was pressed down 0.3 mm. Because the core wire 20 needed to be supported at two points, the measurement of the bending load value was started at a position 20 mm from the tip of the core wire 20. This measurement start position was the position of the tip of the stiffness change portion 35. Figure 4 plots the measured values ​​from a position 20 mm from the tip of the core wire 20.

[0053] 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 rigidity varying section 35 is preferably 360 to 450 mm. By using the rigidity varying 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.

[0054] (Marker section 40) 2, 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.

[0055] 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.

[0056] (Coating layer 50) 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. As shown in Figure 2, 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] (Hydrophilic coating layer) 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.

[0061] 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.

[0062] The thickness of the hydrophilic coating layer is not particularly limited, but is preferably, for example, 0.1 to 100 μm.

[0063] As described above, the guidewire 10 according to this embodiment has a flexible core wire 20. The core wire 20 has a distal core section 34 that is the most flexible throughout the entire length of the core wire 20, including its most distal end; a main body section 30 that forms the proximal side of the distal core section 34 and has a constant diameter along the axial direction; and a rigidity change section 35 that forms the section 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. The core wire 20 is supported at two points spaced 5 mm apart, and the load measured when the supported central section is pressed down 0.3 mm vertically with a pressing jig moving at a speed of 5 mm / min is measured. The bending load value y obtained by measuring the load when the length from the distal end of the core wire 20 to the distal end is x is expressed as a quadratic or higher approximation of x. In the guidewire 10 configured as described above, the bending load value y is expressed by an approximation of x to the second or higher degree, where x is the length from the tip of the core wire 20. Therefore, the bending load value increases with increasing distance from the tip. Therefore, rigidity and pushability are improved even in the region up to 300 mm from the tip. Furthermore, in the guidewire 10 configured as described above, the bending load value y is expressed by an approximation of x to the second or higher degree, where x is the length from the tip of the core wire 20. Therefore, the diameter of the core wire 20 changes continuously, and no boundary portion is formed, as in the guidewire 10 disclosed in Patent Document 1. Therefore, pushability is improved. From the above, a guidewire 10 with favorable pushability can be provided.

[0064] The variable rigidity section 35 is provided in a region extending from 20 mm to 500 mm from the tip of the core wire 20. With the guide wire 10 configured in this manner, the region of the core wire 20 extending from the aorta to the common hepatic artery (300 to 400 mm from the tip) becomes flexible, allowing for suitable implementation of hepatic artery chemoembolization.

[0065] Furthermore, the core wire 20 is formed from a single material. With the guide wire 10 configured in this manner, the core wire 20 can be manufactured more easily than when the distal core section 34, the variable rigidity section 35, and the main body section 30 are formed from different materials and then joined together.

[0066] The guide wire 10 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 claims.

[0067] For example, although the guidewire 10 used in hepatic arterial chemoembolization has been given as an example, it goes without saying that the guidewire 10 of the present invention can be used in other procedures.

[0068] Although the core wire 20 has been described as being formed from a single material and having a bending load that varies along the axial direction, the present invention is not limited to this. The stiffness can be varied along the axial direction by using different materials for the main body 30, the stiffness change sections 35, and the distal core section 34. The main body 30, the multiple stiffness change sections 35, and the distal core section 34, each 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 the use of different materials and tapering each section. [Explanation of symbols]

[0069] 10 guidewire, 20 core wire, 30 main body, 34 Tip core part, 35 Stiffness change section, 40 marker section, 50 coating layer, 60 catheters, 90 liver, 200 measuring test equipment, 201 Fixture, 202 Press-down jig, 203 Support feet 204 furrow.

Claims

1. 1. A guidewire having a flexible core wire, The core wire is a distal core portion that is the most flexible of the entire length of the core wire, including the distal end; a main body portion that is located on the base end side of the distal core portion and has a constant diameter along the axial direction; a rigidity varying portion that constitutes a portion from the tip of the main body portion to the base end of the tip core portion, and whose rigidity gradually decreases from the main body portion toward the tip core portion, The core wire is supported at two points spaced 5 mm apart, and the supported central part is pressed down vertically by 0.3 mm with a pressing jig moving at a speed of 5 mm / min. The bending load value y obtained by measuring the bending load is, when the length from the tip of the core wire is defined as x, y is a guidewire expressed by a quadratic or higher approximation of x.

2. The guide wire according to claim 1 , wherein y is expressed by a third-order approximation of x.

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

4. 0.000004x ３ -0.0011x ２ +0.2743x+0.9843≦y≦0.000008x ３ -0.0046x ２ The guide wire according to claim 1 or 2, which is expressed by the approximate formula +1.0276x-1.4543.

5. The guide wire according to claim 1 or 2, wherein the variable rigidity portion is provided in a region of the core wire that is from 20 mm to 500 mm from the tip.

6. The guidewire of claim 1 or 2, wherein the core wire is formed from a single material.

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