Medical device

Abstract

A guide wire 10 (medical device) comprises a first region 10a having first surface characteristics, and a second region 10b having second surface characteristics and located further toward the proximal end than the first region. In the guide wire 10, the first surface characteristics include a characteristic that the surface of the first region 10a has a first frictional resistance value when a frictional wear test is performed on the surface of the first region 10a, and the second surface characteristics include a characteristic that the surface of the second region 10b has a second frictional resistance value when the frictional wear test is performed on the surface of the second region 10b under the same conditions as for the surface of the first region 10a, in which the first frictional resistance value is greater than the second frictional resistance value. The guide wire 10 (medical device) having the above-mentioned configuration is capable of controlling progression of prolapse despite the simple structure thereof.

Description

medical devices

[0001] The present disclosure relates to medical devices.

[0002] 2. Description of the Related Art Conventionally, medical devices such as guidewires have been used to guide catheter-like medical instruments inserted into tubular organs of the human body, such as blood vessels and digestive organs, to target sites.

[0003] When using a medical device such as a guidewire to guide a device such as a catheter or an indwelling device to a target site within a blood vessel, one technique involves bending the tip of the guidewire back into a U-shape (i.e., in a prolapsed state) and pushing it through the blood vessel (the increasing length of the prolapse is sometimes referred to as the prolapse progressing).

[0004] Patent Document 1 discloses a technology for preventing prolapse from progressing beyond the position of the stiffness difference by providing a stiffness difference in the longitudinal direction of the guidewire. Specifically, at the distal end of the guidewire, the coil surrounding the outer periphery of the core shaft has a two-layer structure of an outer flexible tubular body and an inner flexible tubular body, and the stiffness difference in the longitudinal direction of the guidewire is achieved by displacing the distal end of the inner flexible tubular body toward the proximal end relative to the distal end of the outer flexible tubular body, forming a joint with high stiffness in parts, and tapering the inner flexible tubular body so that its outer diameter decreases toward the distal end. That is, Patent Document 1 utilizes the stiffness difference in the longitudinal direction of the guidewire to control the progression length of prolapse.

[0005] JP 2012-055731 A

[0006] However, when a structure that generates a difference in rigidity is used, such as the guidewire disclosed in Patent Document 1, the guidewire becomes prone to breaking at the portion where the difference in rigidity occurs, i.e., the point where the physical rigidity changes, and once the guidewire is bent, a residual angle remains, resulting in reduced operability. A structure that generates such a difference in rigidity is relatively complex, which also leads to problems such as an increase in the number of component parts, an increase in man-hours, an increase in assembly costs, and other manufacturing burdens.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a medical device that has a simple structure yet is capable of controlling the progression of prolapse.

[0008] To achieve the above object, the present disclosure provides a medical device (Disclosure 1) comprising a first region having a first surface characteristic and a second region having a second surface characteristic and located proximal to the first region.

[0009] According to this disclosure (Disclosure 1), even though the structure is simple, by controlling the surface characteristics of the first region and the second region, it is possible to provide a high-friction region on the tip side and a low-friction region on the base end side, thereby controlling the progression of prolapse.

[0010] In the above disclosure (Disclosure 1), the first surface characteristic includes that when a frictional wear test is performed on the surface of the first region, the surface of the first region has a first frictional resistance value, and the second surface characteristic includes that when a frictional wear test is performed on the surface of the second region under the same conditions as the surface of the first region, the surface of the second region has a second frictional resistance value, and the first frictional resistance value may be greater than the second frictional resistance value (Disclosure 2).

[0011] In the above disclosure (Disclosure 2), when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the first frictional resistance value may be 0.23 N or more (Disclosure 3), when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the second frictional resistance value may be 0.18 N or less (Disclosure 4), when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the difference between the first frictional resistance value and the second frictional resistance value may be 0.04 N or more (Disclosure 5), and when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the value obtained by dividing the first frictional resistance value by the second frictional resistance value may be 1.2 or more (Disclosure 6).

[0012] In the above disclosure (Disclosure 2), when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the first frictional resistance value may be 0.17 N or more (Disclosure 7), when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the second frictional resistance value may be 0.11 N or less (Disclosure 8), when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the difference between the first frictional resistance value and the second frictional resistance value may be 0.05 N or more (Disclosure 9), and when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the value obtained by dividing the first frictional resistance value by the second frictional resistance value may be 1.5 or more (Disclosure 10).

[0013] In the above disclosure (Disclosure 1), the first surface characteristic may include a surface friction coefficient of the first region being a first friction coefficient, and the second surface characteristic may include a surface friction coefficient of the second region being a second friction coefficient, and the first friction coefficient may be greater than the second friction coefficient (Disclosure 11).

[0014] In the above disclosure (Disclosure 11), the first friction coefficient may be 0.1 or more (Disclosure 12), the second friction coefficient may be 0.09 or less (Disclosure 13), the difference between the first friction coefficient and the second friction coefficient may be 0.01 or more (Disclosure 14), or the value obtained by dividing the first friction coefficient by the second friction coefficient may be 1.1 or more (Disclosure 15).

[0015] In the above disclosure (Disclosure 1), the first surface characteristic may include a hydrophobic surface of the first region (Disclosure 16), or the first surface characteristic may include a silicone coating layer formed on the surface of the first region (Disclosure 17), or the second surface characteristic may include a hydrophilic surface of the second region (Disclosure 18), or the second surface characteristic may include a hydrophilic coating layer formed on the surface of the first region (Disclosure 19).

[0016] In the above disclosure (Disclosure 1), the first region may be a region including the tip of the medical device (Disclosure 20).

[0017] The above disclosure (Disclosure 1-20) may comprise a long core shaft and a cylindrical body provided on the outside of the core shaft, and the outer surface of the cylindrical body may be partitioned into a first region located on the tip side and a second region located on the base side of the first region (Disclosure 21).

[0018] 9 is an explanatory diagram showing the structure of a guidewire according to an embodiment of the present disclosure. FIG. 9 is an explanatory diagram showing the structure of a modified guidewire. FIG. 9 is an explanatory diagram showing the structure of a sample guidewire used in a surface frictional resistance value measurement test. FIG. 9 is an explanatory diagram showing the configuration of a measurement device used in a surface frictional resistance value measurement test. FIG. 9 is an explanatory diagram showing a schematic diagram of a measurement point on a sample. FIG. 9 is an explanatory diagram showing a schematic diagram of a blood vessel model used in a prolapse test. FIG. 9 is an explanatory diagram showing a state in which the tip of the guidewire is intentionally hooked on a side branch in a prolapse test. FIG. 9 is an explanatory diagram showing a state in which the tip of the guidewire enters the side branch directly after the state of FIG. 6 in a prolapse test. FIG. 9 is an explanatory diagram showing a state in which the guidewire prolapses and advances through the main vessel without entering the side branch after the state of FIG. 6 in a prolapse test. FIG. 9 is an enlarged view of the tip of the guidewire shown in FIG.

[0019] A guidewire 10 according to an embodiment of the present disclosure will be described below with reference to the drawings. The guidewire 10 is a medical device used to insert a catheter into a blood vessel, a digestive organ, or the like. The distal end of the guidewire 10 is the side that is inserted into the body, and the proximal end of the guidewire 10 is the side that is manipulated by a surgeon such as a doctor. The present disclosure is not limited to the embodiments described below, and the described embodiments are merely examples for explaining the technical features of the present disclosure. Furthermore, the shapes and dimensions shown in the drawings are shown merely to facilitate understanding of the contents of the present disclosure and do not accurately reflect the actual shapes and dimensions.

[0020] As used herein, the term "distal side" refers to the axial direction of the guidewire, in which the guidewire advances toward the target site. The term "proximal side" refers to the axial direction of the guidewire, in the opposite direction from the distal side. The term "distal" refers to the distal end of any component or component, and the term "proximal end" refers to the proximal end of any component or component. Furthermore, the term "distal portion" refers to the portion of any component or component that includes the distal end and extends from the distal end toward the proximal end to the middle of the component, and the term "proximal end" refers to the portion of any component or component that includes the proximal end and extends from the proximal end toward the distal end to the middle of the component. In FIG. 1 , the left side of the illustration is the "distal side" that is inserted into the body, and the right side is the "proximal side" that is operated by the operator.

[0021] 1 is an explanatory diagram showing the structure of a guidewire 10 according to this embodiment. The guidewire 10 comprises a long core shaft 1 and a tubular body 2 provided on the outside of the core shaft 1. A distal tip 3 is provided at the distal end of the guidewire 10 to join the core shaft 1 and the tubular body 2, and a fixing portion 4 is provided at the proximal end of the tubular body 2 to fix the core shaft 1 and the tubular body 2. An inner tubular body 8 is disposed inside the tubular body 2 along the outer periphery of the core shaft 1.

[0022] The core shaft 1 is a long member that serves as the shaft of the guidewire 10. As shown in FIG. 1 , the core shaft 1 has a small-diameter portion 11 on the distal end side and a large-diameter portion 13 on the proximal end side, and a tapered portion 12 between the small-diameter portion 11 and the large-diameter portion 13, the outer diameter of which decreases from the proximal end side to the distal end side. The core shaft 1 can be formed from materials such as stainless steel alloys (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, and tungsten. The material of the core shaft 1 is not limited to these, and the core shaft 1 may be formed from other known materials as long as the core shaft 1 itself is prevented from breaking and the distal end can be rotated.

[0023] The thin-diameter portion 11 has a cylindrical shape with a constant outer diameter from the tip to the base end. Alternatively, the thin-diameter portion 11 may have a flattened cross-sectional shape formed by press working. The thick-diameter portion 13 has a cylindrical shape with a constant outer diameter from the tip to the base end. The tapered portion 12 has a truncated cone shape with an outer diameter that gradually increases from the tip to the base end, and its second moment of area also gradually increases from the tip to the base end.

[0024] The cylindrical body 2 is wound around the core shaft 1 so as to cover the outer periphery of the small diameter portion 11 , the tapered portion 12 and part of the large diameter portion 13 of the core shaft 1 .

[0025] The cylindrical body 2 may be a single coil formed by spirally winding a single wire with a circular cross section into a cylindrical shape, or a hollow stranded coil formed by twisting together multiple wires into a cylindrical shape. The cylindrical body 2 may be formed by combining a single coil and a hollow stranded coil. The cylindrical body 2 may be formed, for example, from a stainless steel alloy (SUS302, SUS304, SUS316, etc.), a superelastic alloy such as a Ni-Ti alloy, a radiolucent alloy such as piano wire, a nickel-chromium alloy, or a cobalt alloy, or a radiopaque alloy such as gold, platinum, tungsten, or an alloy containing these elements (e.g., a platinum-nickel alloy). The material of the cylindrical body 2 is not limited to these, and it may be formed from other known materials. In this embodiment, the distal end of the cylindrical body 2 is formed from a radiopaque alloy, and the proximal end is formed from a stainless steel alloy, and the outer diameter thereof is configured to be approximately constant from the distal end to the proximal end.

[0026] A distal tip 3 is formed at the distal end of the guide wire 10 (i.e., the distal end of the core shaft 1) to join the core shaft 1 and the tubular body 2. The distal tip 3 is formed of a metal solder such as silver solder, gold solder, zinc, an Sn—Ag alloy, or an Au—Sn alloy, and this metal solder fastens the distal end of the core shaft 1 to the distal end of the tubular body 2. The distal tip 3 may also be formed of an adhesive such as an epoxy adhesive, and the distal end of the core shaft 1 and the distal end of the tubular body 2 may be fastened together by the adhesive.

[0027] A fixing portion 4 is formed at the base end of the cylindrical body 2, fixing the core shaft 1 and the cylindrical body 2 together. The fixing portion 4 is formed of a metal solder such as silver solder, gold solder, zinc, an Sn—Ag alloy, or an Au—Sn alloy, and the base end of the cylindrical body 2 is fixed to the large diameter portion 13 of the core shaft 1 by this metal solder. The fixing portion 4 may be formed of an adhesive such as an epoxy adhesive, and the large diameter portion 13 of the core shaft 1 and the base end of the cylindrical body 2 may be fixed by the adhesive.

[0028] Two joints 5a and 5b are formed inside the cylindrical body 2 to join the tapered portion 12 of the core shaft 1 to the cylindrical body 2. The joints 5a and 5b are formed of a metal solder such as silver solder, gold solder, zinc, an Sn—Ag alloy, or an Au—Sn alloy, and the tapered portion 12 of the core shaft 1 is fixed to the cylindrical body 2 by this metal solder. The joints 5a and 5b may be formed of an adhesive such as an epoxy adhesive, and the tapered portion 12 of the core shaft 1 and the cylindrical body 2 may be fixed to each other by the adhesive.

[0029] The inner cylindrical body 8 is shorter than the cylindrical body 2, and is wound around the outside of the core shaft 1 so as to cover the outer periphery of the core shaft 1 from the small diameter portion 11 to part of the tapered portion 12. As a result, the cylindrical body 2 and the inner cylindrical body 8 overlap on the outside of the core shaft 1 only at the distal end of the guide wire 10.

[0030] The distal end of the inner cylindrical body 8 is fixed to the distal tip 3, and the proximal end of the inner cylindrical body 8 is fixed to the tapered portion 12 of the core shaft 1 by a joint 5c. The joint 5c may be formed of a metal solder such as silver solder, gold solder, zinc, a Sn—Ag alloy, or a Au—Sn alloy, or may be formed of an adhesive such as an epoxy adhesive.

[0031] The inner cylindrical body 8 may be a single coil formed by spirally winding a single wire with a circular cross section into a cylindrical shape, or a hollow stranded coil formed by twisting multiple wires together into a cylindrical shape. The inner cylindrical body 8 may be formed by combining a single coil and a hollow stranded coil. The inner cylindrical body 8 may be formed, for example, from a stainless steel alloy (e.g., SUS302, SUS304, SUS316), a superelastic alloy such as a Ni-Ti alloy, a radiolucent alloy such as piano wire, a nickel-chromium alloy, or a cobalt alloy, or a radiopaque alloy such as gold, platinum, tungsten, or an alloy containing these elements (e.g., a platinum-nickel alloy). The material of the inner cylindrical body 8 is not limited to these, and other known materials may also be used. In this modification, the entire inner cylindrical body 8 is formed as a single member made of the same material, and its outer diameter is constant from the distal end to the proximal end.

[0032] The outer peripheral surface of the tubular body 2 is partitioned into a first surface region 21 located on the distal side and a second surface region 22 located closer to the proximal end than the first surface region 21, with the surface characteristics of the first surface region 21 being different from the surface characteristics of the second surface region 22. The tubular body 2 having the first surface region 21 and the second surface region 22 on its outer peripheral surface is provided on the outside of the core shaft 1, so that the guidewire 10 comprises a first region 10a having the first surface characteristics and a second region 10b having the second surface characteristics and located closer to the proximal end than the first region 10a. The first region 10a of the guidewire 10 is a region that includes the distal end of the guidewire 10.

[0033] The first surface characteristic of the first region 10a is that when a friction and wear test is performed on the first region 10a, the first region 10a has a first friction resistance value R １ The second surface characteristic of the second region 10b is that when a friction and wear test is performed on the second region 10b under the same conditions as the first region 10a, the second region 10b has a second friction resistance value R ２ In the guide wire 10, the first frictional resistance value R １ is the second friction resistance value R ２By controlling the surface characteristics of the first region 10a and the second region 10b in this manner, a high-friction region can be provided at the distal end of the guide wire 10 and a low-friction region at the proximal end, thereby controlling the progression of prolapse.

[0034] Specifically, when a friction and wear test was performed using a known friction and wear tester at a test load of 1.96 N and a test speed of 120 mm / min, the first friction resistance value R １ In the process of inserting the guide wire 10 into a blood vessel, prolapse begins when the distal end portion (first region 10a) of the guide wire 10 gets caught on a point where the main vessel branches into a side branch or on the blood vessel wall. １ If the first frictional resistance value R is 0.23 N or more, during the process of inserting the guide wire 10 into a blood vessel, the distal end portion of the guide wire 10 may get caught on the blood vessel wall or a portion where the main vessel branches into a side branch, which may trigger the guide wire 10 to prolapse appropriately. １ If the force is 0.23 N or more, even if the prolapse progresses excessively during the process of inserting the guidewire 10 into a blood vessel in a prolapsed state, the extension length of the prolapse can be restored to an appropriate state by pulling the guidewire 10 toward the proximal end.

[0035] When a friction and wear test was performed using a known friction and wear tester at a test load of 1.96 N and a test speed of 120 mm / min, the second friction resistance value R ２ In the process of inserting the guide wire 10 into a blood vessel with the distal end portion of the guide wire 10 prolapsed, the second frictional resistance value R ２When the force is 0.18 N or less, friction sufficient to advance prolapse does not occur between the second region 10b of the guidewire and the blood vessel wall or the like within the blood vessel, and the advancement of prolapse stops at an appropriate position. The boundary between the first region 10a (first surface region 21) and the second region 10b (second surface region 22) is the reference position for determining how far the advancement of prolapse is permitted in the guidewire 10, so the lengths of the first region 10a and the second region 10b can be determined arbitrarily depending on the application of the guidewire 10, etc.

[0036] In particular, when a friction and wear test was performed using a known friction and wear tester at a test load of 1.96 N and a test speed of 120 mm / min, the first friction resistance value R １ and the second friction resistance value R ２ It is preferable that the difference between the first friction resistance value R and the second friction resistance value R is 0.04 N or more. １ is the second friction resistance value R ２ It is preferable that the value obtained by dividing by is 1.2 or more. By adopting a structure including the first region 10a and the second region 10b having such surface characteristics, it is possible to realize a guidewire 10 in which the extension length of the prolapse is appropriately controlled.

[0037] Alternatively, when a friction and wear test is performed using a known friction and wear tester at a test load of 1.47 N and a test speed of 120 mm / min, the first friction resistance value R １ In the process of inserting the guide wire 10 into a blood vessel, prolapse begins when the distal end portion (first region 10a) of the guide wire 10 gets caught on a point in the blood vessel where the main vessel branches into a side branch, or on the blood vessel wall or the like. １ If the first frictional resistance value R is 0.17 N or more, during the process of inserting the guide wire 10 into a blood vessel, the distal end portion of the guide wire 10 may get caught on the blood vessel wall or a portion where the main vessel branches into a side branch, which may trigger the guide wire 10 to prolapse appropriately. １If the force is 0.17 N or more, even if the prolapse progresses excessively during the process of inserting the guidewire 10 into a blood vessel in a prolapsed state, the extension length of the prolapse can be restored to an appropriate state by pulling the guidewire 10 toward the proximal end.

[0038] When a friction and wear test was performed using a known friction and wear tester at a test load of 1.47 N and a test speed of 120 mm / min, the second friction resistance value R ２ In the process of inserting the guide wire 10 into a blood vessel with the distal end portion of the guide wire 10 prolapsed, the second frictional resistance value R ２ When the force is 0.11 N or less, friction sufficient to advance the prolapse does not occur between the second region 10b of the guidewire and the blood vessel wall or the like inside the blood vessel, and the advancement of the prolapse stops at an appropriate position.

[0039] In particular, when a friction and wear test was performed using a known friction and wear tester at a test load of 1.47 N and a test speed of 120 mm / min, the first friction resistance value R １ and the second friction resistance value R ２ It is preferable that the difference between the first friction resistance value R and the second friction resistance value R is 0.05 N or more. １ is the second friction resistance value R ２ It is preferable that the value obtained by dividing by is 1.5 or more. By adopting a structure including the first region 10a and the second region 10b having such surface characteristics, it is possible to realize a guidewire 10 in which the extension length of the prolapse is appropriately controlled.

[0040] In this embodiment, the first surface characteristic of the first region 10a (first surface region 21) is that the surface friction coefficient of the first region 10a is a first friction coefficient μ １ The second surface characteristic of the second region 10b (second surface region 22) may be such that the surface friction coefficient of the second region 10b is a second friction coefficient μ ２ In this case, the guide wire 10 may have a first friction coefficient μ １ is the second friction coefficient μ ２By controlling the surface characteristics of the first region 10a and the second region 10b in this manner, a high-friction region can be provided at the distal end of the guide wire 10 and a low-friction region at the proximal end, thereby controlling the progression of prolapse.

[0041] Specifically, the first friction coefficient μ １ is preferably 0.1 or more, and the second friction coefficient μ ２ It is preferable that the surface characteristic of the guide wire 10 is 0.09 or less. By adopting a structure including the first region 10a and the second region 10b having such surface characteristics, it is possible to realize a guide wire 10 in which the extension length of the prolapse is appropriately controlled.

[0042] In particular, the first friction coefficient μ １ and the second friction coefficient μ ２ It is preferable that the difference between the first friction coefficient μ and the second friction coefficient μ is 0.01 or more. １ The second friction coefficient μ ２ It is preferable that the value obtained by dividing by is 1.1 or more. By adopting a structure including the first region 10a and the second region 10b having such surface characteristics, it is possible to realize a guidewire 10 in which the extension length of the prolapse is appropriately controlled.

[0043] The first friction coefficient μ, which is the surface friction coefficient of the first region 10a １ and a second friction coefficient μ which is the surface friction coefficient of the second region 10b. ２ The relationship between the above may be adjusted, for example, by forming a coating layer of a different material in each region, by forming a coating layer only in one region, by subjecting each region to a different surface treatment, or by forming a coating layer of the same material in each region and then subjecting only the coating layer formed in one region to a surface treatment.

[0044] In this embodiment, a first coating layer 6 is formed on the surface of the first region 10a of the guidewire 10, and a second coating layer 7 is formed on the surface of the second region 10b. The surface friction coefficient μ of the first coating layer 6 is １ is the surface friction coefficient μ of the second coating layer 7 ２The materials of the first coating layer 6 and the second coating layer 7 are selected so that the thickness of the first coating layer 6 and the second coating layer 7 is greater than .

[0045] The first coating layer 6 is a silicone coating layer, and can be formed by a known coating formation method, such as applying a medical-grade silicone solution to the distal end side of the cylindrical body 2 and the surface of the distal tip 3. That is, in this embodiment, the first surface characteristic of the first region 10a is that the surface of the first region 10a is hydrophobic, and a silicone coating layer is formed as the first coating layer 6 on the surface of the first region 10a.

[0046] The second coating layer 7 is a hydrophilic coating layer and can be formed by a known coating formation method, for example, by applying a solution of a nonionic hydrophilic polymer such as polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, polymethylacrylamide, poly(2-hydroxyethyl methacrylate), or poly(N-hydroxyethylacrylamide), an anionic hydrophilic polymer such as polyacrylic acid, polymethacrylic acid, polymaleic acid, carboxymethyl cellulose, hyaluronic acid, or poly(2-acrylamido-2-methylpropanesulfonic acid), or a cationic hydrophilic polymer such as polyethyleneimine, polyallylamine, or polyvinylamine to the surfaces of the base end side of the cylindrical body 2, the fixing portion 4, and the base end side of the large diameter portion 13 of the core shaft 1. That is, in this embodiment, the second surface characteristic of the second region 10b is that the surface of the second region 10b is hydrophilic, and a hydrophilic coating layer is formed on the surface of the second region 10b as the second coating layer 7.

[0047] According to this guidewire 10, by providing the first region 10a, which is a high-friction region, on the distal side and the second region 10b, which is a low-friction region, on the proximal side, the guidewire 10 becomes easily bendable up to the vicinity of the boundary between the first region 10a and the second region 10b, and a guidewire in which the progression of prolapse beyond the vicinity of the boundary toward the proximal end is suppressed can be obtained. In other words, by providing the first surface region 21, which is a high-friction region, on the distal side and the second surface region 22, which is a low-friction region, on the surface of the tubular body 2 provided on the outside of the core shaft 1 of the guidewire 10, the guidewire 10 becomes easily bendable up to the vicinity of the boundary between the first surface region 21 and the second surface region 22, and a guidewire in which the progression of prolapse beyond the vicinity of the boundary toward the proximal end is suppressed can be obtained. With such a guidewire 10, it is possible to appropriately determine how to provide the first surface region 21 and the second surface region 22 on the surface of the tubular body 2, eliminating the need to create a rigidity gap by making the structure of the guidewire complex as in the past, and the progression of prolapse can be suppressed at any position despite the simple structure. In particular, the surface friction coefficient can be easily changed by changing the state and type of coating in each region, thereby increasing the degree of freedom in designing the guidewire.

[0048] The guidewire as a medical device according to the present disclosure has been described above with reference to the drawings. The present disclosure is not limited to the above-described embodiment, and various modifications are possible. For example, the above-described embodiment describes an example in which the core shaft has a thick-diameter portion on the proximal end side, a thin-diameter portion on the distal end side, and a tapered portion between the thick-diameter portion and the thin-diameter portion. The shape of the core shaft is not limited to this.

[0049] <Modification> A modification of the guidewire described in the above embodiment will be described below with reference to Fig. 2. In the modified guidewire 10A, the same components as those in the previously described guidewire 10 are designated by the same reference numerals, and their description will be omitted. Fig. 2 is an explanatory diagram showing the structure of a modification of the guidewire of the present disclosure, and the modified guidewire 10A differs from the previously described guidewire 10 in that it does not have a silicone coating layer (first coating layer 6) that covers the first region 10a.

[0050] In this modification, the outer peripheral surface of the tubular body 2 is divided into a first surface region 21 located on the distal side and a second surface region 22 located closer to the proximal end than the first surface region 21, and the surface characteristics of the first surface region 21 are different from the surface characteristics of the second surface region. The tubular body 2, having the first surface region 21 and the second surface region 22 on its outer peripheral surface, is provided on the outside of the core shaft 1, so that the guidewire 10A includes a first region 10Aa having first surface characteristics. Furthermore, the guidewire 10A includes a second region 10Ab having second surface characteristics and located closer to the proximal end than the first region 10Aa. The first region 10Aa of the guidewire 10A is a region that includes the distal end of the guidewire 10A.

[0051] Even if the first region 10Aa is not coated, if the surface friction coefficient of the first region 10Aa is greater than the surface friction coefficient of the second region 10Ab, which is coated with the second coating layer 7, the guide wire 10A will be more likely to prolapse up to the vicinity of the boundary between the first region 10Aa and the second region 10Ab, and the guide wire will be one in which the progression of prolapse toward the base end beyond the vicinity of the boundary is suppressed.

[0052] The present disclosure will be described in more detail below with reference to examples, etc. However, the scope of the present disclosure is not limited to these examples, etc.

[0053] <Test for measuring surface frictional resistance> Samples were prepared by forming different coating layers on the distal end T of the sample guide wire S shown in FIG. 3, and friction and wear tests were performed on these samples to measure the frictional resistance of the surface of the distal end T.

[0054] (Sample Guidewire) The sample guidewire S has a stainless steel alloy core shaft 1S having the same shape as the core shaft used in the aforementioned guidewires 10 and 10A. A single coil 2S, formed by spirally winding a wire with a circular cross section into a cylindrical shape, is wound around the core shaft 1S, covering the outer periphery of the thin-diameter section, the tapered section, and part of the thick-diameter section. A distal tip 3S (silver solder) is formed at the distal end of the sample guidewire S (i.e., the distal end of the core shaft 1S) to join the core shaft 1S to the single coil 2S. A fixing portion 4S (silver solder) is formed at the proximal end of the single coil 2S to fix the core shaft 1S to the single coil 2S. A joint portion 5S (silver solder) is formed inside the single coil 2S to join the tapered section of the core shaft 1S to the single coil 2S. At the distal end T of the sample guidewire S, the pitch of the single coil 2S is slightly expanded over a length of approximately 15 mm from the tip.

[0055] (Samples) Samples S1-S5 were produced by forming different coating layers on the distal end T of sample guidewire S. Samples S1-S3 had a hydrophilic coating layer formed on the distal end T, sample S4 had a silicone coating layer formed on the distal end T, and sample S5 had no coating on the distal end T. The details of the produced samples S1-S5 are shown in Table 1.

[0056]

[0057] (Friction and Wear Test) The frictional resistance values ​​in this test are dynamic frictional resistance values. For the friction and wear test, a friction and wear tester TYPE: 38 manufactured by Shinto Scientific Co., Ltd. was used. FIG. 4 shows the configuration of the friction and wear tester 100. The friction and wear tester 100 is configured so that a sample guide wire S (samples S1-S5) can be fixed on a horizontally movable measurement stage 110 using a sample fixture 111, and when a weight 130 is placed on a weight tray 121 attached to the end of an arm 120, a measuring indenter 122 attached to the weight tray 121 is pressed against the sample guide wire S by the weight of the weight 130. In this test, a urethane sheet (thickness: 0.5 mm, hardness: Shore A90) attached to the underside of a substantially cylindrical measuring indenter 122 was attached, and the underside of the measuring indenter 122 was brought into contact with the tip T of each of the samples S1-S5, and the measurement stage 110 was moved to the right, thereby measuring the frictional resistance using the measuring indenter 122. The friction and wear tests were conducted at two test loads, 1.96 N (200 gf) and 1.47 N (150 gf), and a test speed of 120 mm / min. Specifically, as shown in FIG. 5, the tests were conducted on each of samples S1-S5 from four directions (up, down, left, and right), and the frictional resistance value was measured for each measurement point over a measurement length (longitudinal distance) of 10 mm and a measurement time of 5 seconds. The frictional resistance value was calculated by excluding the influence of static frictional resistance. Specifically, the resistance values ​​measured between 1 and 5 seconds out of the measurement time of 0 to 5 seconds were used, and the average was used as the frictional resistance value of the tip portion T of each of samples S1-S5. FIG. 5 is a schematic diagram showing the direction from which measurements were conducted on samples S1-S5 (where the measurement points were set on samples S1-S5) when viewed from the cross-sectional direction of samples S1-S5.

[0058] The measurement results of the friction resistance values ​​of the tip portions T of samples S1-S5 are shown in Table 2 when the test load was 1.96 N (200 gf), and in Table 3 when the test load was 1.47 N (150 gf).

[0059]

[0060]

[0061] <Prolapse Test> (Production of Examples) The guidewires of Examples 1 to 7 of the present disclosure were produced using the above-described sample guidewire S. Specifically, seven types of guidewires were produced as Examples 1 to 7, each having various coatings applied to the distal and proximal sides of the sample guidewire S, with a boundary set at a position 5 mm from the distal end. The coating conditions on the distal side and proximal side of the boundary for each of Examples 1 to 7 are shown in Table 4.

[0062]

[0063] The "silicone coating" in Examples 1-4 above refers to a coating layer formed on the same silicone coating layer as the sample S4 described above. The "hydrophilic coating (large thickness)" in Example 6 above refers to a coating layer formed on the same hydrophilic coating layer as the sample S1 described above. The "hydrophilic coating (medium thickness)" in Examples 4, 5, and 7 above refers to a coating layer formed on the same hydrophilic coating layer as the sample S2 described above. The "hydrophilic coating (small thickness)" in Examples 3, 5, and 6 above refers to a coating layer formed on the same hydrophilic coating layer as the sample S3 described above. The "uncoated" in Example 1 above refers to an uncoated guidewire, similar to the sample S5 described above. Therefore, the surface friction resistance values ​​of the distal and proximal ends of the guidewires according to Examples 1-7 are as shown in Tables 2 and 3.

[0064] (Prolapse Test 1) The tip of the guidewire according to Examples 1-7 was shaped, and with the tip gently shaped as when a doctor uses a guidewire, it was inserted tip-first into a silicone blood vessel model M shown in Figure 6, and a test was conducted to confirm whether prolapse would occur. In the blood vessel model M, five side branches A, B, C, D, and E branch off from the middle of a main vessel V, and the side branches A-E are formed so that the connection angle θ with the main vessel V gradually increases in this order. The angle θ formed by the side branch A and the main vessel V Ａ is 15 degrees, and the angle between the side branch B and the main pipe V is θ Ｂ is 30 degrees, and the angle between the side branch C and the main pipe V is θＣ is 45 degrees, and the angle between the side branch D and the main pipe V is θ Ｄ is 60 degrees, and the angle between the side branch E and the main pipe V is θ Ｅ The angle is 90 degrees. The inner diameter of the main vessel V is Φ3.0 mm, and the inner diameters of the side branches A, B, C, D, and E are Φ1.5 mm. Specifically, the guidewires according to Examples 1-7 were inserted distally into this vascular model from its proximal end (the right side in Figure 6 ). The tips of the guidewires were intentionally hooked onto the side branches A-E ( Figure 7 ). A test was conducted to determine whether the tips would enter the side branches ( Figure 8 ) or whether they would protrude and advance through the main vessel V without entering the side branches ( Figure 9 ). The test results are shown in Table 5. Figure 10 shows an enlarged view of the distal end of the prolapsed guidewire. In Figure 10 , L indicates the length of the prolapse, and P indicates the starting point of the prolapse.

[0065]

[0066] The above results indicate that prolapse occurs when the surface frictional resistance of the distal end of the guidewire is above a certain level. In particular, with the guidewires of Examples 1, 2, 3, and 4, which had frictional resistance values ​​of 0.17 N or greater when the frictional wear test was conducted at a test load of 1.47 N and a test speed of 120 mm / min (0.23 N or greater when the frictional wear test was conducted at a test load of 1.96 N and a test speed of 120 mm / min), it was found that even when the side branch had a large connection angle θ with the main conduit V, the distal end of the guidewire did not enter the side branch but instead prolapsed and advanced through the main conduit V. That is, if the frictional resistance of the surface of the distal end of the guidewire was 0.17 N or greater when the frictional wear test was conducted at a test load of 1.47 N and a test speed of 120 mm / min (0.23 N or greater when the frictional wear test was conducted at a test load of 1.96 N and a test speed of 120 mm / min), prolapse began appropriately. If the frictional resistance value was less than this, prolapse may not begin even if the tip of the guidewire was hooked, depending on the condition of the side branch.

[0067] (Prolapse Test 2) Next, the guidewires according to Examples 1-4 were inserted into the main duct V of a silicone blood vessel model shown in Figure 5 with their tips bent approximately 30 mm from the beginning, and a test was conducted to confirm how the length of the prolapse changed when the guidewires were repeatedly pushed and pulled. The test results are shown in Table 6.

[0068]

[0069] The above results indicate that, even if excessive prolapse occurs (even if the prolapse progression length becomes longer than expected), further prolapse progression does not occur and the prolapse progression can be stopped as long as the surface frictional resistance value of the proximal end of the guidewire is below a certain level. It can also be seen that the prolapse progression length can be returned to a length equal to or less than the length at the time of insertion by pulling the guidewire back toward the proximal end. In particular, the guidewires of Examples 3 and 4, which had frictional resistance values ​​of 0.11 N or less when subjected to a frictional wear test at a test load of 1.47 N and a test speed of 120 mm / min (0.18 N or less when subjected to a frictional wear test at a test load of 1.96 N and a test speed of 120 mm / min), were able to return the prolapse progression length to a length near the boundary (5 mm from the tip). That is, if the frictional resistance value of the surface on the proximal end side of the guidewire is 0.11 N or less when the frictional wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min (0.18 N or less when the frictional wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min), the extension length of the ProPlus can be appropriately controlled. If the frictional resistance value is greater than that, the extension of the ProPlus may become unstoppable depending on the condition of the blood vessel wall.

[0070] REFERENCE SIGNS LIST 10, 10A Guide wire 10a, 10Aa First region 10b, 10Ab Second region 1 Core shaft 11 Thin diameter section 12 Tapered section 13 Thick diameter section 2 Cylindrical body 21 First surface region 22 Second surface region 3 Distal tip 4 Fixation section 5a, 5b, 5c Joint section 6 First coating layer 7 Second coating layer 8 Inner cylindrical body

Claims

1. a first region having a first surface characteristic; and a second region having a second surface characteristic and located on the proximal side of the first region, the medical device comprising.

2. wherein the first surface characteristic includes that when a friction and wear test is performed on the surface of the first region, the surface of the first region has a first friction resistance value; wherein the second surface characteristic includes that when a friction and wear test is performed on the surface of the second region under the same conditions as the surface of the first region, the surface of the second region has a second friction resistance value; The medical device according to claim 1, wherein the first friction resistance value is greater than the second friction resistance value.

3. The medical device according to claim 2, wherein when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the first friction resistance value is 0.23 N or more.

4. The medical device according to claim 2 or 3, wherein when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the second friction resistance value is 0.18 N or less.

5. The medical device according to any one of claims 2 to 4, wherein when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the difference between the first friction resistance value and the second friction resistance value is 0.04 N or more.

6. The medical device according to any one of claims 2 to 5, wherein when the friction and wear test is performed at a test load of 1.96 N and a test speed of 120 mm / min, the value obtained by dividing the first friction resistance value by the second friction resistance value is 1.2 or more.

7. The medical device according to any one of claims 2 to 6, wherein when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the first friction resistance value is 0.17 N or more.

8. The medical device according to any one of claims 2 to 7, wherein when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the second friction resistance value is 0.11 N or less.

9. The medical device according to any one of claims 2 to 8, wherein when the friction and wear test is performed at a test load of 1.47 N and a test speed of 120 mm / min, the difference between the first friction resistance value and the second friction resistance value is 0.05 N or more.

10. When the friction and wear test is performed under a test load of 1.47 N and a test speed of 120 mm / min, the medical device according to any one of claims 2 to 9, wherein a value obtained by dividing the first friction resistance value by the second friction resistance value is 1.5 or more.

11. The first surface property includes that the surface friction coefficient of the first region is a first friction coefficient. The second surface property includes that the surface friction coefficient of the second region is a second friction coefficient. The medical device according to claim 1, wherein the first friction coefficient is larger than the second friction coefficient.

12. The medical device according to claim 11, wherein the first friction coefficient is 0.1 or more.

13. The medical device according to claim 11 or 12, wherein the second friction coefficient is 0.09 or less.

14. The medical device according to any one of claims 11 to 13, wherein a difference between the first friction coefficient and the second friction coefficient is 0.01 or more.

15. The medical device according to any one of claims 11 to 14, wherein a value obtained by dividing the first friction coefficient by the second friction coefficient is 1.1 or more.

16. The medical device according to any one of claims 1 to 15, wherein the first surface property includes that the surface of the first region is hydrophobic.

17. The medical device according to any one of claims 1 to 16, wherein the first surface property includes that a silicone coating layer is formed on the surface of the first region.

18. The medical device according to any one of claims 1 to 17, wherein the second surface property includes that the surface of the second region is hydrophilic.

19. The medical device according to any one of claims 1 to 18, wherein the second surface property includes that a hydrophilic coating layer is formed on the surface of the second region.

20. The medical device according to any one of claims 1 to 19, wherein the first region is a region including the tip of the medical device.

21. A long core and A cylindrical body provided outside the core, and The medical device according to any one of claims 1 to 20, wherein an outer peripheral surface of the cylindrical body is partitioned into a first surface region located on a tip side and a second surface region located on a base end side with respect to the first surface region.