Patent Application
20240042177
The technique disclosed in the present specification relates to a guide wire.
A guide wire is used to guide a medical device (hereinafter, referred to as a “combined device”) such as a catheter to a predetermined position inside a human body. The guide wire includes a core shaft and a coil body in which a wire is helically wound around the outer periphery of the core shaft.
A hydrophilic coating layer is provided on the outer periphery of the coil body in order to improve lubricity of the guide wire. The coating layer absorbs moisture inside a human body and swells. When a combined device guided by the guide wire is pressed against the coating layer of the guide wire at a bent portion or the like of the combined device, the coating layer is crushed to have a smooth surface, and moisture is extruded from the coating layer to form a thin moisture membrane between the smooth surface of the coating layer and the combined device; as a result, lubricity between the guide wire and the combined device is ensured.
Conventionally, a technique of making the shape of a surface of the coating layer covering a base material layer have irregularities in order to improve lubricity of a medical device has been known (see Patent Literature 1, for example).
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2013-146504
In the conventional guide wire, when a combined device is pressed against the coating layer, the coating layer is crushed, and the combined device comes into contact with the wire of the coil body, possibly causing decrease in lubricity of the guide wire. Note that, the combined device cannot be prevented from coming into contact with the wire of the coil body only by making the shape of the surface of the coating layer have irregularities without considering the positional relation with the coil body as in the conventional technique, still possibly causing decrease in lubricity of the guide wire. It can be also considered that the thickness of the coating layer is increased in order to avoid contact between the combined device and the wire of the coil body; however, merely by increasing the thickness of the coating layer, the thickness of the coating layer becomes excessively large when swelling, possibly causing deterioration in passability of the combined device. As described above, there is room for improvement regarding achievement of both lubricity and passability of a combined device in conventional guide wires.
The present specification discloses a technique capable of solving the above-described problem.
The technique disclosed herein can be implemented, for example, as the following aspects.
As described above, since the coating layer of the present guide wire is configured to have the peak portion protruding in the outer peripheral direction of the guide wire in the swollen state, the peak portion in the coating layer effectively exhibits a water retention function, and high lubricity is imparted to the guide wire. In the present guide wire, on a cross-section including the central axis of the coil body, an apex of the peak portion of the coating layer in the swollen state is present at a position on the more proximal end side than the first virtual straight line passing the central point of one transverse section of the wire and perpendicular to the central axis and at a position on the more distal end side than the second virtual straight line passing the central point of another transverse section of the wire and perpendicular to the central axis, the another transverse section being adjacent to and on the proximal end side of the one transverse section. That is, the apex of the peak portion of the coating layer in the swollen state is positioned between coils of the wire of the coil body. The portion of the coating layer positioned between coils of the wire is a portion with large “allowance” when receiving stress from the outer peripheral side, since the presence of the wire as a base is minor therein. Therefore, when the apex of the peak portion is present in the above-described portion of the coating layer, stress from a combined device can be dispersed. Accordingly, according to the present guide wire, a combined device can be effectively prevented from coming into contact with the wire of the coil body even when the coating layer is crushed. In addition, the portion of the coating layer positioned between coils of the wire easy moves since the presence of the wire as a base is minor therein; therefore, passability of a combined device can be successfully maintained even when the apex of the peak portion of the coating layer is positioned between coils of the wire of the coil body. In view of the above, according to the present guide wire, both lubricity and passability of a combined device can be achieved at a high level.
As described above, in the present guide wire, on the cross-section including the central axis of the coil body, the thickness of the second coating layer on the perpendicular bisector of the virtual line segment connecting the first central point, which is the central point of one transverse section of the wire, and the second central point, which is the central point of another transverse section of the wire, is relatively thick, the another transverse section being adjacent to and on the proximal end side of the one transverse section. Therefore, according to the present guide wire, the configuration in which the apex of the peak portion of the coating layer in a swollen state is present at a position on the more proximal end side than the first virtual straight line and at a position on the more distal end side than the second virtual straight line can be realized. Accordingly, according to the present guide wire, both lubricity and passability of a combined device can be achieved at a high level.
The technique disclosed herein can be realized in various aspects, for example, in an aspect of a guide wire, a method of producing same, and the like.
The guide wire 100 is a long medical device inserted into a human body for guiding a combined device such as a catheter to a predetermined position inside a human body. The guide wire 100 has a total length of, for example, about 1500 mm to 3200 mm.
The guide wire 100 includes a core shaft 10, a coil body 20, a coating layer 30, a distal end side joint part 51, a proximal end side joint part 56, and an intermediate fixing part 61.
The core shaft 10 is a long member extending along the central axis AX. The core shaft 10 has a small diameter portion 11, a first tapered portion 12, a first large diameter portion 13, a second tapered portion 14, and a second large diameter portion 15 in the order from the distal end side toward the proximal end side. The small diameter portion 11 is a portion positioned at the most distal end of the core shaft 10, in which the outer diameter of the core shaft 10 is smallest. The first tapered portion 12 is a portion portioned between the small diameter portion 11 and the first large diameter portion 13 and having a tapered shape in which the outer diameter thereof increases from the distal end side toward the proximal end side. The first large diameter portion 13 is a portion portioned between the first tapered portion 12 and the second tapered portion 14 and having an outer diameter larger than the outer diameter of the small diameter portion 11. The second tapered portion 14 is a portion positioned between the first large diameter portion 13 and the second large diameter portion 15 and having a tapered shape in which the outer diameter thereof increases from the distal end side toward the proximal end side. The second large diameter portion 15 is a portion portioned at the most proximal end of the core shaft 10, in which the outer diameter of the core shaft 10 is largest. The second large diameter portion 15 is a portion held by a technician such as a surgeon. The shape of the transverse section (XY cross-section) at each position of the core shaft 10 may be any shape but is, for example, a circular shape or a flat-plate shape. The diameter and the length of each portion of the core shaft 10 can be arbitrarily set.
The core shaft 10 is formed from, for example, stainless steel (SUS302, SUS304, SUS316, etc.), a Ni—Ti alloy, a piano wire, a nickel-chromium-based alloy, a cobalt alloy, tungsten, or the like. The core shaft 10 may be formed from another superelastic alloy or another linear pseudo-elastic alloy.
The coil body 20 is a coiled member formed by helically winding a wire 21 to have a hollow cylindrical shape extending along the central axis AX. The coil body 20 is disposed on the outer periphery of the core shaft 10 so as to cover the core shaft 10. In the present embodiment, the coil body 20 covers the small diameter portion 11, the first tapered portion 12, and the first large diameter portion 13 of the core shaft 10. The wire 21 constituting the coil body 20 may be a solid wire composed of one strand or a twisted wire in which a plurality of strands is twisted. When the wire 21 is a solid wire, the coil body 20 is configured as a single coil, and when the wire 21 is a twisted wire, the coil body 20 is configured as a hollow twisted coil. The coil body 20 may be configured by combining a single coil and a hollow twisted coil. The wire diameter of the wire 21 and the average coil diameter (average diameter of the outer diameter and the inner diameter of the coil body 20) of the coil body 20 may be arbitrarily set. The coil body 20 is preferably a sparsely wound coil in which intervals are provided between coils of the wire 21 adjacent to each other in the axis direction. The coil body 20 may be a densely wound coil in which coils of the wire 21 adjacent to each other in the axis direction are close to each other.
The wire 21 constituting the coil body 20 is formed from, for example, a radiolucent material such as stainless steel (SUS302, SUS304, SUS316, etc.), a Ni—Ti alloy, or a piano wire; or a radiopaque material such as platinum, gold, tungsten, a cobalt alloy, a nickel-chromium-based alloy, or an alloy thereof. The wire 21 constituting the coil body 20 may be formed from another superelastic alloy or another linear pseudo-elastic alloy.
The distal end side joint part 51 is a member joining the distal end of the coil body 20 and the distal end (small diameter portion 11) of the core shaft 10. The proximal end side joint part 56 is a member joining the proximal end of the coil body 20 and the core shaft 10 (first large diameter portion 13). The intermediate fixing part 61 is a member joining the coil body 20 and the core shaft 10 (first large diameter portion 13) in the vicinity of the intermediate portion in the central axis AX direction of the coil body 20. The distal end side joint part 51, the proximal end side joint part 56, and the intermediate fixing part 61 are formed from, for example, metal solder (Au—Sn alloy, Sn—Ag alloy, Sn—Pb alloy, Pb—Ag alloy, etc.), a brazing material (aluminum alloy solder, silver solder, gold solder, etc.), an adhesive (epoxy-based adhesive, etc.), or the like. The materials forming the distal end side joint part 51, the proximal end side joint part 56, and the intermediate fixing part 61 may be identical or may differ from one another.
The coating layer 30 is a hydrophilic resin layer provided on the outer periphery of the coil body 20. The coating layer 30 covers at least an outer peripheral surface (outer surface) of the coil body 20. The coating layer 30 in the present embodiment also covers a surface on the distal end side of the distal end side joint part 51 and a surface on the proximal end side of the proximal end side joint part 56. The coating layer 30 may cover at least part of a surface of the second tapered portion 14 and/or the second large diameter portion 15 of the core shaft 10. The coating layer 30 improves lubricity of the guide wire 100 by absorbing moisture in a human body to swell.
Next, a configuration of the coating layer 30 will be described in more detail.
As illustrated in
The outer coating layer 32 has swellability higher than that of the inner coating layer 31. High swellability of the coating layer herein means that the coating layer swells more (retains more water) when the coating layer is impregnated with physiological saline. A swollen film thickness, which is an amount of change in the film thickness measured using a laser microscope or the like can be used as an index value representing the level of swellability of the coating layer. The swollen film thickness of the outer coating layer 32 is preferably 1.2 times or more, more preferably 1.5 times or more, and still more preferably 2.0 times or more the swollen film thickness of the inner coating layer 31. The swollen film thickness of the coating layer can be measured using VFX series (manufactured by KEYENCE CORPORATION), which are laser microscopes, OPTELICS series (manufactured by Lasertec Corporation), which are white confocal microscopes, and F40 series (manufactured by Filmetrics, INC.), which are optical interference film thickness meters. Especially, in a case where VFX-8710, which is a laser microscope, is used, the swollen film thickness can be measured as follows: the guide wire 100, in a dry state, provided with a predetermined hydrophilic coating is observed, the dry film thickness from the coil body 20 to the surface of the coating layer is measured, and physiological saline is then dropped onto a portion to be observed to cause the coil body 20 and the coating layer 30 to be immersed in physiological saline for seconds or longer, and the coil body 20 and the coating layer 30 are then further measured with the laser microscope.
For example, as a material for forming the inner coating layer 31, polyvinyl alcohol (PVA), hydrophilic urethane resin (for example, Hydro Thane (Mitsubishi Chemical Corporation), Hydro MED (Mitsubishi Chemical Corporation), Bionate (DSM), Tecophilic (Lubrizol), HPU (Dainichiseika Color & Chemicals Mfg. Co., Ltd.)), modified polyolefin resin (for example, polyethylene-acrylic acid (UNITIKA LTD.), BONDINE (TOKYO ZAIRYO CO., LTD.)), and the like can be used, and polyvinyl alcohol (PVA) and hydrophilic urethane resin (Hydro Thane) can be especially preferably used. As a material for forming the outer coating layer 32, hyaluronic acid, carboxybetaine, phosphobetaine, sulfobetaine, polyvinylpyrrolidone, maleic acid, acrylic acid, methacrylic acid, dimethylacrylamide, methoxyethyl acrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, polyethylene glycol, copolymers thereof, and the like can be used, and hyaluronic acid, carboxybetaine, phosphobetaine, dimethylacrylamide, and copolymers thereof can be more preferably used. When the inner coating layer 31 and the outer coating layer 32 are formed using these materials, swellability of the outer coating layer 32 can be made higher than that of the inner coating layer 31.
As illustrated in
On the cross-section including the central axis AX of the coil body 20 in the coating layer 30 (30d) in the normal state, the first thickness T2b of the outer coating layer 32 on the perpendicular bisector VL3 is preferably 1.2 times or more the second thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and is 1.2 times or more the third thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2, and is more preferably 2 times or more the thickness T2ad and 2 times or more the thickness T2ap. In addition, the first thickness T2b of the outer coating layer 32 on the perpendicular bisector VL3 is preferably 5 times or less the second thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and 5 times or less the third thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2, and is more preferably 3.5 times or less the second thickness T2ad and 3.5 times or less the third thickness T2ap. The first thickness T2b of the outer coating layer 32 on the perpendicular bisector VL3 is, for example, about 1.5 μm to 4.0 μm, and the second thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and the third thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2 are, for example, about 0.5 μm to 2.0 μm. The second thickness T2ad and the third thickness T2ap may be the same or different.
In the present embodiment, in the coating layer 30 (30d) in the normal state, the thickness of the inner coating layer 31 at the position between coils of the wire 21 is thicker than that at the position immediately above the wire 21 of the coil body 20. More specifically, on the cross-section (cross-section illustrated in
When the coating layer 30 is shifted to the swollen state from the normal state, as illustrated in
An apex P2 of the peak portion 36 is not positioned immediately above the wire 21 of the coil body 20 but positioned between coils of the wire 21. More specifically, on the cross-section (cross-section illustrated in
In the present embodiment, on the cross-section including the central axis AX of the coil body 20 in the coating layer 30 (30w) in the swollen state, the apex P2 of the peak portion 36 is present at a position not overlapping the transverse sections of the wire 21 in the direction (in the example of
On the cross-section including the central axis AX of the coil body 20 in the coating layer 30 (30w) in the swollen state, the thickness T2b of the outer coating layer 32 at the position of the apex P2 of the peak portion 36 is, for example, about 4.0 μm to 16.0 μm, and the thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and the thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2 are, for example, about 1.0 μm to 6.0 μm.
A method of producing a guide wire 100 of the present embodiment is, for example, as follows. First, a coil body 20 is joined to a core shaft 10 by a joint part (a distal end side joint part 51, a proximal end side joint part 56, and an intermediate fixing part 61) to prepare a guide wire 100 before forming a coating layer 30. The guide wire 100 is cleaned, if needed.
Next, an inner coating layer 31 with relatively low swellability is formed for the guide wire 100 by a predetermined film forming method. For example, a solution for the inner coating layer 31 is prepared using a resin material with relatively low swellability, and the inner coating layer 31 is formed by dip coating using the solution. Then, an outer coating layer 32 with relatively high swellability is formed, by a predetermined film forming method, for the guide wire 100 with the inner coating layer 31 formed therein. For example, a solution for the outer coating layer 32 is prepared using a resin material with relatively high swellability, and the outer coating layer 32 is formed by dip coating using the solution. The guide wire 100 provided with a coating layer 30 composed of the inner coating layer 31 and the outer coating layer 32 can be produced by the above method.
When the outer coating layer 32 is formed, the thickness of the outer coating layer 32 at a position between coils of the wire 21 is thicker than that at a position immediately above the wire 21 of the coil body 20. A configuration in which the apex P2 of the peak portion 36 of the coating layer 30 is positioned immediately above the wire 21 of the coil body 20 but positioned between coils of the wire 21 when the coating layer 30 is shifted from the normal state (dry state) to the swollen state can be realized in this manner. Adjustment of the extent to which the peak portion 36 of the coating layer 30 protrudes in the swollen state can be achieved by, for example, adjusting the thicknesses of the outer coating layer 32 and the inner coating layer 31 or by adjusting the distance between coils of the wire 21 of the coil body 20.
The guide wire 100 of the present embodiment has the above-described configuration and thus can achieve both lubricity and passability of a combined device at a high level. Hereinafter, this point will be described.
As illustrated in
As the coating layer 30X of the comparative example has such a configuration in the normal state, when the normal state is shifted to the swollen state, a peak portion 36 protruding in the outer peripheral direction of the guide wire 100X is formed as illustrated in
In the comparative example, the apex P2 of the peak portion 36 of the coating layer 30X (30Xw) in the swollen state is positioned immediately above the wire 21 of the coil body 20 as illustrated in
In the comparative example, it is also considered that the thickness of the coating layer 30X is thickened so as to avoid contact between the combined device DE and the wire 21 of the coil body 20. However, when the thickness of the coating layer 30X is simply thickened, the thickness of the portion (peak portion 36) positioned immediately above the wire 21 of the coil body 20 in the coating layer 30X becomes excessively large in the swollen state, possibly causing deterioration in passability of the combined device DE.
On the other hand, in the guide wire 100 of the present embodiment, the coating layer 30 is configured to have the peak portion 36 protruding in the outer peripheral direction of the guide wire 100 in the swollen state. Therefore, the peak portion 36 in the coating layer 30 effectively exhibits a water retention function, and high lubricity is imparted to the guide wire 100.
In the guide wire 100 of the present embodiment, on the cross-section including the central axis AX of the coil body 20, the apex P2 of the peak portion 36 of the coating layer 30 in the swollen state is present at a position on the proximal end side of the first virtual straight line VL1 passing through the first central point P1d of the first transverse section 21d of the wire 21 of the coil body 20 and perpendicular to the central axis AX and at a position on the distal end side of the second virtual straight line VL2 passing through the second central point P1p of the second transverse section 21p of the wire 21 of the coil body 20 and perpendicular to the central axis AX, the second transverse section 21p being adjacent to and on the proximal end side of the first transverse section 21d. That is, the apex P2 of the peak portion 36 of the coating layer 30 in the swollen state is present between coils of the wire 21 of the coil body 20. The portion of the coating layer positioned between coils of the wire 21 is a portion less affected by the wire 21 as a base and thus is a portion with large “allowance” when receiving stress from the outer peripheral side. Therefore, when the apex P2 of the peak portion 36 is present in the above-described portion of the coating layer 30 (in other words, when the volume of the coating layer 30 is large in the above-described portion), stress from the combined device DE can be dispersed. Accordingly, according to the guide wire 100 of the present embodiment, the combined device DE is effectively prevented from coming into contact with the wire 21 of the coil body 20 even when the coating layer 30 is crushed.
Since the presence of the wire 21 as a base is minor in the portion of the coating layer 30 positioned between coils of the wire 21, the portion of the coating layer 30 positioned between coils of the wire 21 easily moves, and passability of the combined device DE is thus successfully maintained even when the apex P2 of the peak portion 36 of the coating layer 30 is positioned between coils of the wire 21 of the coil body 20.
In view of the above, according to the guide wire 100 of the present embodiment, both lubricity and passability of the combined device DE can be achieved at a high level.
In the present embodiment, on the cross-section including the central axis AX of the coil body 20, the apex P2 of the peak portion 36 is present at a position not overlapping the transverse sections of the wire 21 of the coil body 20 in the direction perpendicular to the central axis AX. The portion of the coating layer 30 present at a position not overlapping the transverse sections of the wire 21 of the coil body 20 in the direction perpendicular to the central axis AX is a portion significantly less affected by the wire 21 as a base and thus is a portion with significantly large “allowance” when receiving stress from the outer peripheral side. Therefore, when the apex P2 of the peak portion 36 is present in the above-described portion of the coating layer 30, stress from the combined device DE can be effectively dispersed. Accordingly, according to the guide wire 100 of the present embodiment, the combined device DE is more effectively prevented from coming into contact with the wire 21 of the coil body 20 even when the coating layer 30 is crushed, and lubricity of the guide wire 100 can be more effectively improved.
In the guide wire 100 of the present embodiment, the coating layer 30 includes the inner coating layer 31 that is provided on the outer periphery of the coil body 20 and the outer coating layer 32 that is provided on the outer periphery of the inner coating layer 31 and has swellability higher than that of the inner coating layer 31. In the normal state, on the cross-section including the central axis AX of the coil body 20, the thickness T2b of the outer coating layer 32 on the perpendicular bisector VL3 is thicker than the thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and thicker than the thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2. As the guide wire 100 of the present embodiment has such a configuration, the configuration in which the apex P2 of the peak portion 36 of the coating layer 30 in the swollen state is present at a position on the more proximal end side than the first virtual straight line VL1 and at a position on the more distal end side than the second virtual straight line VL2 can be realized. Accordingly, according to the guide wire 100 of the present embodiment, as described above, both lubricity and passability of the combined device DE can be achieved at a high level.
In the normal state, on the cross-section including the central axis AX of the coil body 20, the thickness T2b of the outer coating layer 32 on the perpendicular bisector VL3 is preferably 1.2 times or more the thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and 1.2 times or more the thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2. With such a configuration, the configuration in which in the coating layer 30 in a swollen state, the thickness of the portion positioned between coils of the wire 21 of the coil body 20 is thicker than the thickness of the portion positioned immediately above the wire 21 by a certain factor or more can be realized, and both lubricity and passability of the combined device DE can be achieved at a higher level.
The technology disclosed in the present specification is not limited to the embodiment described above and may be modified into various aspects without departing from the spirit thereof and may be modified as described below, for example.
The configuration of the guide wire 100 according to the above-described embodiment is merely an example and may be modified in various manners. For example, although the coating layer 30 has a two layer structure with the inner coating layer 31 and the outer coating layer 32 in the above-described embodiment, the coating layer 30 may have a structure with three or more layers in which one or more other layers are disposed between the inner coating layer 31 and the outer coating layer 32.
Although, on the cross-section including the central axis AX of the coil body 20 in the coating layer 30 (30w) in the swollen state, the apex P2 of the peak portion 36 is positioned on the perpendicular bisector VL3 or in the immediate vicinity thereof in the above-described embodiment, the apex P2 of the peak portion 36 may be present at another position as long as the position is neither on the first virtual straight line VL1 nor on the second virtual straight line VL2.
Although, the peak portion 36 is helically and continuously formed in the coating layer 30 (30w) in the swollen state, in the above-described embodiment, the peak portion 36 may be discretely formed.
Although the relationship in which the apex P2 of the peak portion 36 is present at a position on the more proximal end side than the first virtual straight line VL1 and at a position on the more distal end side than the second virtual straight line VL2 is established for an arbitrary pair of transverse sections of the wire 21 adjacent to each other on an arbitrary cross-section including the central axis AX of the coil body 20 in the above-described embodiment, the relationship may be established for at least one pair of transverse sections of the wire 21 adjacent to each other on at least one cross-section including the central axis AX of the coil body 20. Similarly, the relationship in which the thickness T2b of the outer coating layer 32 on the perpendicular bisector VL3 is thicker than the thickness T2ad of the outer coating layer 32 on the first virtual straight line VL1 and thicker than the thickness T2ap of the outer coating layer 32 on the second virtual straight line VL2 is established for an arbitrary pair of transverse sections of the wire 21 adjacent to each other on an arbitrary cross-section including the central axis AX of the coil body 20 in the above-described embodiment, the relationship may be established for at least one pair of transverse sections of the wire 21 adjacent to each other on at least one cross-section including the central axis AX of the coil body 20.
Hereinafter, an example of disclosed embodiments will be described for more clearly describing the contents of the disclosed embodiments described above.
First, a guide wire 100 (guide wire 100 before forming a coating layer 30) including a core shaft 10, a coil body 20, a distal end side joint part 51, a proximal end side joint part 56, and an intermediate fixing part 61 was prepared, and a surface of the guide wire 100 was scraped using unwoven fabric into which isopropyl alcohol (IPA) was penetrated to clean same.
Next, polyvinyl alcohol (molecular weight: 2600, saponification degree: 98% or more, product name: NH26-S manufactured by Mitsubishi Chemical Corporation) was dissolved in hot water at a concentration of 5%, and 0.16% of polycarbodiimide (manufactured by Nisshinbo Holdings Inc., product name: Carbodilite) was subsequently added as a cros slinking agent to obtain a solution for an inner coating layer 31. Dip coating was conducted on the guide wire 100 before forming a coating layer 30 using the obtained solution, followed by heating and drying at 70° C. for one hour to obtain a guide wire 100 with an inner coating layer 31 formed therein.
Sodium hyaluronate (molecular weight: about one million) was dissolved in a mixture solution (water: N-methylpyrrolidone=85:15) at a concentration of 0.8 wt % to obtain a solution for an outer coating layer 32. Dip coating was conducted on the guide wire 100 with the inner coating layer 31 formed therein using the obtained solution, followed by heating and drying at 120° C. for one hour to form an outer coating layer 32. A guide wire 100 provided with a coating layer 30 composed of the inner coating layer 31 and the outer coating layer 32 was obtained thereby.
Film shape Evaluation Method
As measurement of a swollen film thickness, after immersing, in physiological saline for 20 seconds, the guide wire 100 of Example 1 with the coating layer 30 formed therein, the transparent film cross-section was measured with a laser using a laser microscope (VFX-8710, manufactured by KEYENCE CORPORATION).
A portion of a balloon catheter (Kamui 3.00 mm×15 mm, manufactured by ASAHI INTECC CO., LTD.), which is a combined device for the guide wire 100, on the proximal end side from 105 mm from the distal end side is wound once around a column with an outer diameter of 30 mm to reproduce a bent portion of a coronary artery. The guide wire 100 of Example 1 was inserted into the balloon catheter in this state, and lubricity at that time was evaluated. As a result, it was demonstrated that resistance during insertion of the guide wire 100 of Example 1 was significantly small, and high lubricity was exhibited.
As a more severe test, the guide wire 100 was repeatedly inserted into and removed from the balloon catheter 50 times, and a change in lubricity was evaluated. As a result, no change in the resistance value was found even after repeating insertion and removal 50 times in Example 1, and high lubricity was maintained.
From the above observation result and the above evaluation result, it was observed that when the peak portion 36 of the coating layer 30 (30w) was pressed against the balloon catheter, which was the combined device, at the position between coils of the wire 21 of the coil body 20 in the guide wire 100, the peak portion 36 deformed to provide a moisture membrane to the apex of the wire 21 of the coil body 20, and high lubricity was thus maintained.
The disclosed embodiments are not limited to the conditions of the above example, and various base materials and coating agents can be selected without departing from the spirit of the disclosed embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-077038 | Apr 2021 | JP | national |
This is a Continuation of Application No. PCT/JP2022/018007 filed Apr. 18, 2022, which claims priority to JP 2021-077038 filed Apr. 30, 2021. The disclosure of the prior applications is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2022/018007 | Apr 2022 | US |
| Child | 18379279 | US |
