Catheter

Abstract

To provide a catheter with excellent safety, the catheter provided with a tube having a reinforcing layer composed of metal wires.SOLUTION: A catheter comprises a tube 11 having a longitudinal direction extending from a proximal side to a distal side and a radial direction perpendicular to the longitudinal direction. The tube 11 includes a resin inner layer 12, a reinforcing layer 13 provided radially outside the inner layer 12 and including a first metal wire 14A and a second metal wire 14B disposed in a braided manner, and a resin outer layer 17 provided radially outside the reinforcing layer 13. The reinforcing layer 13 has a bulge 16 formed by melting the first metal wire 14A at a distal end of the first metal wire 14A, and a bulge 16 formed by melting the second metal wire 14B at a distal end of the second metal wire 14B.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a catheter having a tube with a reinforcing layer made of metal wire. [Background technology]

[0002] Conventionally, catheters including a tube with a reinforcing layer made of metal wires have been known. For example, Patent Document 1 discloses a catheter including an inner layer made of resin, a braided body formed around the inner layer and composed of first and second wires, and an outer layer made of resin around the braided body, where the first and second wires are joined at a joint where the tip of the first wire covers the side of the second wire. Patent Document 2 discloses a catheter including a tubular braided body in which a first set of metal wires and a second set of metal wires intersect at multiple intersections, where two wires are welded at a corner region including one of four corners when viewed from the outer periphery, and the weld is formed on the inner wire only in a portion of the width direction when viewed from the outer periphery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-033682 [Patent Document 2] Japanese Patent Publication No. 2022-150880 Summary of the Invention [Problem to be solved by the invention]

[0004] A tube having a reinforcing layer made of metal wire is usually constructed by disposing the reinforcing layer between an inner resin layer and an outer resin layer. A catheter equipped with such a tube is required to ensure that the metal wire constituting the reinforcing layer does not break through the outer layer or protrude from the distal end of the tube, thereby preventing the metal wire from being exposed and damaging the body lumen.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide a catheter that is equipped with a tube having a reinforcing layer made of metal wire, and that is highly safe. [Means for solving the problem]

[0006] The catheter of the present invention that can solve the above problems is as follows. [1] A catheter having a tube with a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, wherein the tube has an inner layer made of resin, a reinforcing layer provided radially outside the inner layer and having a braided arrangement of first and second metal wires, and an outer layer made of resin provided radially outside the reinforcing layer, wherein the reinforcing layer has a bulge at the distal end of the first metal wire where the first metal wire is melted, and a bulge at the distal end of the second metal wire where the second metal wire is melted. [2] A catheter as described in [1], wherein the thickness of the bulge portion of the first metal wire is thicker than the thickness of the first metal wire other than the bulge portion, and the thickness of the bulge portion of the second metal wire is thicker than the thickness of the second metal wire other than the bulge portion. [3] A catheter as described in [1] or [2], wherein an intersection between the first metal wire and the second metal wire is present at the distal end of the reinforcing layer, and at the intersection, the bulge portion of the first metal wire and the bulge portion of the second metal wire are melted and integrated. [4] The catheter according to any one of [1] to [3], wherein the melting point of the first metal wire is the same as the melting point of the second metal wire. [5] The catheter according to any one of [1] to [4], wherein the first metal wire and the second metal wire are made of the same metal. [6] A catheter described in any one of [1] to [5], wherein the bulge portion of the first metal wire is coated with the resin of the outer layer from the outside to the inside of the radial direction of the first metal wire, and the bulge portion of the second metal wire is coated with the resin of the outer layer from the outside to the inside of the radial direction of the second metal wire. [7] The catheter according to any one of [1] to [6], wherein the inner layer extends distally beyond the distal end of the reinforcing layer. [Effects of the Invention]

[0007] The catheter of the present invention includes a tube having a reinforcing layer made of a metal wire, and a bulge formed by melting the metal wire at the distal end of the metal wire. This prevents the distal end of the metal wire from becoming sharp, making it less likely for the metal wire to break through the outer layer that covers the outside of the reinforcing layer or to protrude from the distal end of the tube. This reduces the risk of the metal wire being exposed and damaging the body lumen, resulting in a highly safe catheter. [Brief explanation of the drawings]

[0008] [Figure 1] 1 shows an example of a catheter of the present invention, and is a side view of the catheter. [Figure 2] 2 shows an example of a side view of a distal portion of a tube provided in the catheter shown in FIG. 1. [Figure 3] 3 shows a cross-sectional view of the tube shown in FIG. 2 taken along line III-III. [Figure 4] 1. FIG. 4 shows another example of a side view of the distal portion of the tube provided in the catheter shown in FIG. [Figure 5] 5 shows a VV cross-sectional view of the tube shown in FIG. 4. [Figure 6] 1A and 1B show an example of a method for manufacturing a tube provided in a catheter of the present invention, and are schematic diagrams of the method for manufacturing a tube. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification and other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0010] A catheter according to an embodiment of the present invention comprises a tube having a reinforcing layer in which metal wires are arranged in a braided state, and the reinforcing layer has a bulge formed by melting the metal wires at the distal end of the braided metal wires. Because the catheter of the present invention has a tube with a reinforcing layer configured in this manner, the distal end of the metal wires is not sharp, making it less likely that the metal wires will break through the outer layer that covers the outside of the reinforcing layer or protrude from the distal end of the tube. This makes it less likely that the exposed metal wires will damage the body lumen, resulting in a highly safe catheter.

[0011] Examples of catheters include guiding catheters, electrode catheters, ablation catheters, balloon catheters, mapping catheters, microcatheters, stent delivery systems, etc., and the type is not particularly limited. The catheter has an operating section on the proximal side and a shaft provided distal to the operating section, and the above-described tube having the reinforcing layer can be applied to part or all of the shaft. The catheter of the present invention will be described in detail below with reference to the drawings.

[0012] Figure 1 shows an example of the configuration of a guiding catheter as an example of a catheter of the present invention, Figure 2 shows an example of a side view of the distal portion of a tube provided in the catheter shown in Figure 1, Figure 3 shows a III-III cross-sectional view of the tube shown in Figure 2, Figure 4 shows another example of a side view of the distal portion of a tube provided in the catheter shown in Figure 1, and Figure 5 shows a VV cross-sectional view of the tube shown in Figure 4.

[0013] The catheter 10 shown in FIG. 1 includes a tube 11 and an operating unit 21 provided on the proximal side of the tube 11. The tube 11 has a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction. The longitudinal direction of the tube 11 refers to the direction in which the tube 11 extends, and the tube 11 has an inner lumen extending in the longitudinal direction. The radial direction refers to the direction perpendicular to the longitudinal direction, extending radially from the center of the tube 11. The longitudinal direction of the catheter 10 is also determined based on the longitudinal direction of the tube 11. The catheter 10 and the tube 11 have a proximal side and a distal side, which are on one side and the other side of the longitudinal direction. The proximal side refers to the side of the catheter 10 closest to the user, i.e., the operator, and the distal side refers to the opposite side of the proximal side, i.e., the side toward the treatment target.

[0014] 2 to 5, the tube 11 has a resin inner layer 12, a reinforcing layer 13 provided radially outside the inner layer 12 and having metal wires 14 arranged in a braided state, and a resin outer layer 17 provided radially outside the reinforcing layer 13. Note that in Figs. 2 and 4, the reinforcing layer 13 is covered by the outer layer 17 and is not exposed, but for ease of understanding, the reinforcing layer 13 is represented by a solid line.

[0015] The operation unit 21 preferably has a treatment port 22 that communicates with the inner cavity of the tube 11. A guide wire or a treatment device can be inserted through the treatment port 22. The operation unit 21 may also have a fluid injection port 23 for a drug, contrast agent, or the like. The fluid injection port 23 communicates with the inner cavity of the tube 11, and by injecting a drug, contrast agent, or the like from the fluid injection port 23, the drug, contrast agent, or the like can be supplied into the body through the tube 11.

[0016] The length of the tube 11 is not particularly limited and may be set appropriately depending on the type of catheter 10 and whether the tube 11 is applied to a portion or the entire shaft of the catheter 10. The length of the tube 11 may be, for example, about 100 mm to 3000 mm. The inner diameter of the tube 11 is preferably, for example, about 0.25 mm to 3.50 mm. The outer diameter of the tube 11 is preferably, for example, about 0.30 mm to 3.80 mm. The thickness of the tube 11 is preferably, for example, about 0.05 mm to 0.30 mm.

[0017] There are no particular limitations on the type of resin that constitutes the inner layer 12 and the outer layer 17. Examples of resins that constitute the inner layer 12 and the outer layer 17 include synthetic resins such as polyester resins such as polyethylene terephthalate, polyamide resins such as nylon, polyolefin resins such as polyethylene and polypropylene, aromatic polyether ketone resins such as PEEK, polyurethane resins, polyether polyamide resins, polyimide resins, polyamide imide resins, fluorine-based resins such as PTFE, PFA, and ETFE, polyvinyl chloride resins, and silicone resins. The inner layer 12 and the outer layer 17 may be composed of the same resin or different resins.

[0018] The reinforcing layer 13 is formed by arranging metal wires 14 in a predetermined pattern and is disposed between the inner layer 12 and the outer layer 17. Examples of materials that can be used for the metal wires 14 of the reinforcing layer 13 include stainless steels such as SUS304 and SUS316, carbon steel, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, nickel-titanium alloys, cobalt-chromium alloys, and tungsten alloys, with stainless steel being preferred. The metal wires 14 may be solid wires or stranded wires.

[0019] The metal wires 14 of the reinforcing layer 13 are arranged in a braided configuration, which effectively increases the rigidity of the tube 11. Specifically, the metal wires 14 include first metal wires 14A and second metal wires 14B, and the reinforcing layer 13 is formed by arranging the first metal wires 14A and the second metal wires 14B in a braided configuration. Preferably, the first metal wires 14A extend in a clockwise spiral from one side to the other in the longitudinal direction of the tube 11, and the second metal wires 14B extend in a counterclockwise spiral from one side to the other in the longitudinal direction of the tube 11. Preferably, the first metal wires 14A and the second metal wires 14B intersect with each other at one or more locations. A plurality of first metal wires 14A and a plurality of second metal wires 14B may be provided.

[0020] The reinforcing layer 13 has a bulge 16 at the distal end of the first metal wire 14A formed by melting the first metal wire 14A, and a bulge 16 at the distal end of the second metal wire 14B formed by melting the second metal wire 14B. The bulge 16 can be formed as a molten ball of the first metal wire 14A or the second metal wire 14B. FIG. 2 shows an example in which the bulge 16 formed at the end of the first metal wire 14A and the bulge 16 formed at the end of the second metal wire 14B are joined at the intersection 15 of the first metal wire 14A and the second metal wire 14B. FIG. 4 shows an example in which the bulge 16 is formed independently at the end of the first metal wire 14A and the end of the second metal wire 14B.

[0021] As described above, by forming bulges 16 at the distal end of first metal wire 14A and the distal end of second metal wire 14B, the distal end of first metal wire 14A and the distal end of second metal wire 14B do not become sharp, and first metal wire 14A and second metal wire 14B are less likely to break through outer layer 17 or protrude from the distal end of tube 11. Therefore, first metal wire 14A and second metal wire 14B are less likely to be exposed and damage the body lumen, resulting in a highly safe catheter 10.

[0022] As shown in Fig. 2, the bulge 16 of the first metal wire 14A and the bulge 16 of the second metal wire 14B are preferably formed at the intersection 15 between the first metal wire 14A and the second metal wire 14B. Specifically, the intersection 15 between the first metal wire 14A and the second metal wire 14B is preferably present at the distal end of the reinforcing layer 13, and the bulge 16 of the first metal wire 14A and the bulge 16 of the second metal wire 14B are preferably fused and integrated at the intersection 15. This allows the first metal wire 14A and the second metal wire 14B to be more firmly joined at the intersection 15 between the first metal wire 14A and the second metal wire 14B, and also makes it easier to form the bulge 16 to be relatively large. That is, a relatively large bulge 16 can be formed at the intersection 15, which is the distal end of the first metal wire 14A and the second metal wire 14B. This makes it less likely that the first metal wire 14A and the second metal wire 14B will break through the outer layer 17 or protrude from the cut end of the tube 11, thereby further improving the safety of the resulting catheter 10.

[0023] As described above, if the first metal wire 14A and the second metal wire 14B are fused and integrated at the intersection 15 between the first metal wire 14A and the second metal wire 14B, the first metal wire 14A and the second metal wire 14B do not separate at the distal end of the reinforcing layer 13, and the reinforcing layer 13 can be stably held in a braided state. For example, even if a metal ring is provided at the distal end of the reinforcing layer 13 and the distal end of the reinforcing layer 13 is not fixed to the metal ring, separation of the first metal wire 14A and the second metal wire 14B can be prevented. In this respect, the tube 11 does not need to have a metal ring to which the first metal wire 14A and the second metal wire 14B are fixed at the distal end of the reinforcing layer 13.

[0024] The first metal wire 14A and the second metal wire 14B may be made of the same metal or different metals. However, it is preferable that the first metal wire 14A and the second metal wire 14B be made of the same metal because it is easier for the first metal wire 14A and the second metal wire 14B to melt and be firmly joined together. This allows the metals of the first metal wire 14A and the second metal wire 14B to be compatible with each other when the first metal wire 14A and the second metal wire 14B are melt-joined, thereby integrating the first metal wire 14A and the second metal wire 14B at the intersection 15. As a result, the bulge 16 formed at the intersection 15 of the first metal wire 14A and the second metal wire 14B can be formed as a homogeneous molten ball. From a similar perspective, it is also preferable that the melting point of the first metal wire 14A is the same as the melting point of the second metal wire 14B.

[0025] As shown in FIGS. 3 and 5 , the thickness of the bulge 16 of the first metal wire 14A is preferably thicker than the thickness of the remaining portion of the first metal wire 14A. The thickness of the bulge 16 of the second metal wire 14B is preferably thicker than the thickness of the remaining portion of the second metal wire 14B. The thicknesses of the first metal wire 14A and the second metal wire 14B refer to the lengths of the first metal wire 14A and the second metal wire 14B in the radial direction of the tube 11. With the bulge 16 thus formed, even if the distal ends of the first metal wire 14A and the second metal wire 14B contact the body lumen, the body lumen is less likely to be damaged. Furthermore, even if a strong shear force is applied between the inner layer 12 or the outer layer 17 and the reinforcing layer 13, the bulge 16 acts as a stopper, making it less likely that the outer layer 17 or the reinforcing layer 13 will peel off.

[0026] 3, when bulge 16 is formed at intersection 15 between first metal wire 14A and second metal wire 14B, bulge 16 is preferably formed to be thicker than the combined thickness of first metal wire 14A and second metal wire 14B. In this case, the thickness of bulge 16 is preferably 1.2 times or more, more preferably 1.3 times or more, and preferably 4.0 times or less, more preferably 3.0 times or less, of the combined thickness of first metal wire 14A and second metal wire 14B.

[0027] As shown in Figure 5, when the bulge 16 is formed at a location other than the intersection 15 between the first metal wire 14A and the second metal wire 14B, the bulge 16 is preferably thicker than the thickness of a single first metal wire 14A or second metal wire 14B. In this case, the thickness of the bulge 16 at the distal end of the first metal wire 14A is preferably at least 1.2 times, more preferably at least 1.5 times, and preferably not more than 5.0 times, more preferably not more than 4.0 times, the thickness of the first metal wire 14A other than the bulge 16. The thickness of the bulge 16 at the distal end of the second metal wire 14B is preferably at least 1.2 times, more preferably at least 1.5 times, and preferably not more than 5.0 times, more preferably not more than 4.0 times the thickness of the second metal wire 14B other than the bulge 16.

[0028] It is preferable that bulge 16 does not protrude significantly beyond first metal wire 14A and second metal wire 14B, other than at intersection 15, when viewed from outside tube 11. At the distal end of first metal wire 14A, excluding intersection 15, bulge 16 does not protrude beyond first metal wire 14A, or the length by which bulge 16 protrudes beyond first metal wire 14A, when viewed from outside tube 11, is preferably 0.3 times or less the width of first metal wire 14A, more preferably 0.2 times or less, and even more preferably 0.1 times or less. At the distal end of the second metal wire 14B excluding the intersection 15, it is preferable that the bulge 16 does not protrude from the second metal wire 14B when viewed from outside the tube 11, or that the length by which the bulge 16 protrudes from the second metal wire 14B is 0.3 times or less the width of the second metal wire 14B, more preferably 0.2 times or less, and even more preferably 0.1 times or less.

[0029] At the distal end of the first metal wire 14A, the length of the bulge 16 in the extension direction of the first metal wire 14A is preferably at least 0.3 times, more preferably at least 0.5 times, and preferably at most 3.0 times, more preferably at most 2.0 times the width of the first metal wire 14A. At the distal end of the second metal wire 14B, the length of the bulge 16 in the extension direction of the second metal wire 14B is preferably at least 0.3 times, more preferably at least 0.5 times, and preferably at most 3.0 times, more preferably at most 2.0 times the width of the second metal wire 14B.

[0030] The first metal wire 14A and the second metal wire 14B are preferably formed in a strip shape. That is, the thickness of the first metal wire 14A is preferably formed to be shorter than the width of the first metal wire 14A (specifically, the width of the first metal wire 14A as viewed from the outside of the tube 11), and the thickness of the second metal wire 14B is preferably formed to be shorter than the width of the second metal wire 14B (specifically, the width of the second metal wire 14B as viewed from the outside of the tube 11). By forming the first metal wire 14A and the second metal wire 14B in this manner, the thickness of the reinforcing layer 13 can be made thin, and the wall thickness of the tube 11 can be made thin. Furthermore, the first metal wire 14A and the second metal wire 14B can be stably overlapped at the intersection 15 between the first metal wire 14A and the second metal wire 14B, making it easy to firmly fuse and integrate the first metal wire 14A and the second metal wire 14B.

[0031] The width of the first metal wire 14A is preferably at least twice the thickness of the first metal wire 14A, more preferably at least three times, and preferably not more than 10 times, more preferably not more than 8 times, and even more preferably not more than 6 times. The width of the second metal wire 14B is preferably at least twice the thickness of the second metal wire 14B, more preferably at least three times, and preferably not more than 10 times, more preferably not more than 8 times, and even more preferably not more than 6 times. The first metal wire 14A and the second metal wire 14B may have a thickness of about 3 μm to 100 μm and a width of about 10 μm to 500 μm, for example.

[0032] The bulge 16 of the first metal wire 14A is preferably coated with the resin of the outer layer 17 from the outside to the inside in the radial direction of the first metal wire 14A. The bulge 16 of the second metal wire 14B is preferably coated with the resin of the outer layer 17 from the outside to the inside in the radial direction of the second metal wire 14B. This more firmly bonds the outer layer 17 and the reinforcing layer 13, making the outer layer 17 less likely to peel off even when a strong shear force is applied between the outer layer 17 and the reinforcing layer 13. This further improves the safety of the catheter 10. In the tube 11, it is more preferable that the resin of the outer layer 17 exists around the entire circumference of the first metal wire 14A in a cross section perpendicular to the extension direction of the first metal wire 14A, and it is more preferable that the resin of the outer layer 17 exists around the entire circumference of the second metal wire 14B in a cross section perpendicular to the extension direction of the second metal wire 14B. In this case, it is preferable that the inner layer 12 and the outer layer 17 are made of different resins.

[0033] 3, when the bulge 16 is formed at the intersection 15 of the first metal wire 14A and the second metal wire 14B, it is preferable that the resin of the outer layer 17 is present from the radially outer side to the radially inner side of the bulge 16. Alternatively, it is preferable that the resin of the outer layer 17 is present from the radially outer side of the metal wire 14 located on the radially outer side of the first metal wire 14A and the second metal wire 14B to the radially inner side of the metal wire 14 located on the radially inner side.

[0034] The inner layer 12 preferably extends distally beyond the distal end of the reinforcing layer 13. This prevents the metal wires 14 from protruding from the distal end of the tube 11, making it less likely that the metal wires 14 will damage the lumen of the body, thereby improving the safety of the catheter 10. Furthermore, the presence of the inner layer 12 distal to the distal end of the reinforcing layer 13 makes it easier to insert a guidewire or other treatment tools into the lumen of the tube 11. The tube 11 may have the inner layer 12 and outer layer 17 extending distally beyond the distal end of the reinforcing layer 13. It is preferable that the inner layer 12 (or even the outer layer 17) extends distally from the distal end of the reinforcing layer 13 by preferably at least 0.1 times, more preferably at least 0.2 times, and even more preferably at least 0.3 times the width of the first metal wire 14A or the second metal wire 14B, and it is also preferable that the inner layer 12 (or even the outer layer 17) extends distally from the distal end of the reinforcing layer 13 by preferably at most 3.0 times, more preferably at most 2.0 times, and even more preferably at most 1.5 times the width of the first metal wire 14A or the second metal wire 14B.

[0035] Although not shown in the drawings, the reinforcing layer 13 may have a bulge 16 formed by melting the first metal wire 14A at a proximal end of the first metal wire 14A, and a bulge 16 formed by melting the first metal wire 14A at a proximal end of the second metal wire 14B. Furthermore, an intersection 15 between the first metal wire 14A and the second metal wire 14B may be present at the proximal end of the reinforcing layer 13, and the bulge 16 of the first metal wire 14A and the bulge 16 of the second metal wire 14B may be melted and integrated at the intersection 15. For details of the bulge 16 formed at the proximal end of the first metal wire 14A and the proximal end of the second metal wire 14B, see the above description of the bulge 16 formed at the distal end of the first metal wire 14A and the distal end of the second metal wire 14B. The inner layer 12 may extend proximally beyond the proximal end of the reinforcing layer 13, and for details of this embodiment, please refer to the description of the embodiment in which the inner layer 12 extends distally beyond the distal end of the reinforcing layer 13 above.

[0036] An example of a method for manufacturing a tube 11 having a reinforcing layer 13 with bulges 16 at the distal end of a first metal wire 14A and the distal end of a second metal wire 14B will be described with reference to Fig. 6. Note that the method for manufacturing the tube 11 is not limited to the embodiment shown in Fig. 6. In Fig. 6, the reinforcing layer 13 is covered by an outer layer 17 and is not exposed, but is represented by a solid line for ease of understanding.

[0037] The tube 11 can be manufactured by a manufacturing method including the steps of: preparing a tube to be cut 31 having a resin inner layer 12; a reinforcing layer 13 provided on the outside of the inner layer 12 and having a braided arrangement of first metal wires 14A and second metal wires 14B; and a resin outer layer 17 provided on the outside of the reinforcing layer 13; a first laser irradiation step of irradiating the tube to be cut 31 with a first laser 41 to cut the first metal wires 14A and the second metal wires 14B and melt the outer layer 17; and a second laser irradiation step of irradiating the tube to be cut 31 with a second laser 42 after the first laser irradiation step to cut the inner layer 12 and obtain a cut tube 32. The cut tube 32 obtained by this manufacturing method can be the above-mentioned tube 11. In Figure 6, the step of preparing a tube to be cut is shown in Figure 6(A), the first laser irradiation step is shown in Figures 6(B) to 6(C), and the second laser irradiation step is shown in Figures 6(C) to 6(D). Figures 2 to 5 are referenced as necessary, and Figures 2 to 5 show a cut tube 32 obtained by the manufacturing method of Figure 6.

[0038] In the step of preparing a tube to be cut, a tube to be cut by a laser, i.e., a tube to be cut 31, is prepared. The tube to be cut 31 has an inner layer 12, a reinforcing layer 13 provided on the outside of the inner layer 12 and having first metal wires 14A and second metal wires 14B arranged in a braided shape, and a resin outer layer 17 provided on the outside of the reinforcing layer 13. The configurations of the inner layer 12, outer layer 17, and reinforcing layer 13 of the tube to be cut 31 are as described above.

[0039] In the first laser irradiation step, as shown in FIG. 6(B), a first laser 41 is irradiated onto the tube to be cut 31 to cut the metal wire 14 of the reinforcing layer 13. FIG. 6(C) shows the tube to be cut 31 in which the metal wire 14 of the reinforcing layer 13 has been cut. The first laser 41 emits light of a wavelength that can be absorbed by the metal wire 14. By irradiating the tube to be cut 31 with the first laser 41, the energy of the first laser 41 is absorbed by the metal wire 14, thereby cutting the metal wire 14 of the reinforcing layer 13. In other words, the absorption of the energy of the first laser 41 by the metal wire 14 heats the metal wire 14, and the metal wire 14 is melted. At this time, the cut end of the metal wire 14 melts, forming a molten ball, i.e., a bulge 16, at the end of the metal wire 14. In the first laser irradiation step, it is preferable to cut the reinforcing layer 13 in a manner that goes around the circumference of the tube 31 to be cut, and thereby it is preferable that the reinforcing layer 13 is separated in the longitudinal direction of the tube 31 to be cut. The cut end of the metal wire 14 means the end of the metal wire 14 cut by the first laser 41.

[0040] When an intersection 15 of the first metal wire 14A and the second metal wire 14B exists at the distal end of the reinforcing layer 13, and the bulge 16 of the first metal wire 14A and the bulge 16 of the second metal wire 14B are to be melted and integrated at the intersection 15, the intersection 15 of the first metal wire 14A and the second metal wire 14B or its vicinity may be irradiated with the first laser 41. This causes the cut end of the first metal wire 14A and the cut end of the second metal wire 14B to melt and be integrated.

[0041] In the first laser irradiation step, it is preferable to cut the metal wire 14 and melt the outer layer 17 by irradiating the first laser 41. The outer layer 17 may be melted by direct absorption of the energy of the first laser 41 by the resin constituting the outer layer 17. However, it is preferable that the metal wire 14 is heated by irradiation with the first laser 41 and then transferred to the outer layer 17. This causes the resin constituting the outer layer 17 to melt preferentially in the area in contact with the metal wire 14, firmly bonding the outer layer 17 and the reinforcing layer 13. This improves the integrity of the cut tube 32 after laser cutting, particularly in the vicinity of the laser cut. Furthermore, the end of the metal wire 14 cut by the first laser 41 is more likely to be covered entirely by the resin of the outer layer 17. As a result, the end face of the metal wire 14 is less likely to be exposed, thereby improving the safety of the resulting catheter 10. On the other hand, the portion of the outer layer 17 that does not overlap with the metal wire 14 does not receive direct heat transfer from the metal wire 14, thereby preventing the entire outer layer 17 from melting. In the first laser irradiation step, the outer layer 17 may be melted and cut by irradiation with the first laser 41.

[0042] From the viewpoint of melting the outer layer 17 in the first laser irradiation step as described above, the outer layer 17 is preferably made of a thermoplastic resin. On the other hand, the inner layer 12 may be made of a thermoplastic resin or a thermosetting resin, but is preferably made of a thermoplastic resin. When the inner layer 12 or the outer layer 17 is made of a thermoplastic resin, the resin that makes up the inner layer 12 or the outer layer 17 has a melting point. When the inner layer 12 is made of a thermosetting resin, the resin that makes up the inner layer 12 has a decomposition point.

[0043] In the first laser irradiation step, it is preferable that the resin of the outer layer 17 is present in the bulge 16 from the outer side to the inner side in the radial direction of the metal wire 14 by irradiation with the first laser 41. When the metal wire 14 is heated by irradiation with the first laser 41 and the heat is transferred to the outer layer 17, and the resin of the outer layer 17 melts, the resin of the outer layer 17 can be present in this way. Even if the resin of the outer layer 17 is present only on the outer side in the radial direction of the metal wire 14 before irradiation with the first laser 41, the metal wire 14 is heated by irradiation with the first laser 41, the heat is transferred to the outer layer 17, and the resin of the outer layer 17 melts, so that the resin of the outer layer 17 flows in a molten state to the inner side in the radial direction of the metal wire 14, and the resin of the outer layer 17 can be present all the way to the inner side in the radial direction of the metal wire 14.

[0044] In the first laser irradiation step, a portion of the inner layer 12 may melt. For example, the metal wire 14 may be heated by irradiation with the first laser 41, and the heat may be transferred to the inner layer 12, thereby melting a portion of the inner layer 12. Note that in the first laser irradiation step, it is preferable to suppress melting of the inner layer 12 as much as possible, and it is more preferable that the inner layer 12 does not melt. It is also preferable that the inner layer 12 is not cut in the first laser irradiation step.

[0045] From the above viewpoints, the melting point or decomposition point of the resin of the inner layer 12 is preferably higher than the melting point of the resin of the outer layer 17. Since the resin of the inner layer 12 is preferably a thermoplastic resin, the melting point of the resin of the inner layer 12 is more preferably higher than the melting point of the resin of the outer layer 17. The difference between the melting point or decomposition point of the resin of the inner layer 12 and the melting point of the resin of the outer layer 17 is preferably 30°C or more, more preferably 40°C or more, and even more preferably 50°C or more. There are no particular limitations on the upper limit of the difference between the melting point or decomposition point of the resin of the inner layer 12 and the melting point of the resin of the outer layer 17, and it may be, for example, 300°C or less, 250°C or less, 200°C or less, or 150°C or less.

[0046] The inner layer 12 is preferably made of a resin with a relatively high melting point or high decomposition point, such as a fluororesin, polyimide resin, polyamideimide resin, silicone resin, or aromatic polyether ketone resin. By using such a resin, the inner surface of the tube 11 formed from the inner layer 12 can be made smooth and the inner surface of the tube 11 can be made sufficiently strong and resistant to damage. On the other hand, the outer layer 17 is preferably made of a resin with a relatively low melting point, such as a polyester resin, polyamide resin, polyolefin resin, polyurethane resin, or polyether polyamide resin.

[0047] It is preferable that the first laser 41 does not directly heat the resin of the inner layer 12. Therefore, it is preferable that the first laser 41 does not oscillate at a wavelength that is absorbed by the resin of the inner layer 12. It is also preferable that the first laser 41 does not directly heat the resin of the outer layer 17. Therefore, it is preferable that the first laser 41 does not oscillate at a wavelength that is absorbed by the resin of the outer layer 17.

[0048] The irradiation width of the first laser 41 (the length over which the first laser 41 is irradiated in the longitudinal direction of the tube 31 to be cut) is preferably 5 times or less, more preferably 3 times or less, even more preferably 2 times or less, and even more preferably 1 time or less, the width of the metal wire 14. This makes it easy to cut the metal wire 14 at a desired location in the longitudinal direction of the tube 31 to be cut when the first laser 41 is irradiated. Furthermore, when forming a bulge 16 at the end of the metal wire 14, it is possible to prevent the bulge 16 from being formed excessively large. There is no particular lower limit to the irradiation width of the first laser 41, and the irradiation width of the first laser 41 may be 0.01 times or more, 0.05 times or more, or 0.1 times or more the width of the metal wire 14, or may be narrower than these.

[0049] After the first laser irradiation step, a second laser irradiation step is performed. In the second laser irradiation step, a second laser 42 is irradiated onto the tube to be cut 31 as shown in Fig. 6(C) to cut the inner layer 12, thereby obtaining a cut tube 32 as shown in Fig. 6(D). The second laser 42 emits light of a wavelength that can be absorbed by the resin of the inner layer 12. By irradiating the tube to be cut 31 after irradiation with the first laser with the second laser 42, the energy of the second laser 42 is absorbed by the resin of the inner layer 12, and the inner layer 12 can be cut.

[0050] In the second laser irradiation step, the tube to be cut 31 may be irradiated with the second laser 42 without removing the cut pieces of the reinforcing layer 13 cut in the first laser irradiation step, or the tube to be cut 31 may be irradiated with the second laser 42 after removing the cut pieces of the reinforcing layer 13 cut in the first laser irradiation step. In the latter case, it is preferable to also remove the outer layer 17 arranged on the outside of the cut pieces of the reinforcing layer 13. Note that the cut pieces of the reinforcing layer 13 refer to the pieces of the reinforcing layer 13 removed by cutting with the first laser 41.

[0051] In the second laser irradiation step, the outer layer 17 may also be cut by irradiating with the second laser 42. In this case, it is preferable that the second laser 42 also oscillates at a wavelength that can be absorbed by the resin of the outer layer 17.

[0052] In the second laser irradiation step, the metal wire 14 of the reinforcing layer 13 may also be cut by irradiating it with a second laser 42. In this case, it is preferable that the second laser 42 also oscillates at a wavelength that can be absorbed by the metal wire 14. In the first laser irradiation step, it is preferable to cut the reinforcing layer 13 in a manner that goes around the circumference of the tube 31 to be cut, that is, to cut the reinforcing layer 13 so as to separate it in the longitudinal direction of the tube 31 to be cut. However, in case some of the metal wire 14 is not cut, the remaining metal wire 14 may be cut in the second laser irradiation step. Alternatively, after cutting the reinforcing layer 13 so as to separate it in the longitudinal direction of the tube 31 to be cut in the first laser irradiation step, the separated cut piece of the reinforcing layer 13 may be cut together with the inner layer 12 or further together with the outer layer 17 in the second laser irradiation step.

[0053] In the second laser irradiation step, it is preferable to cut the inner layer 12 distally of the cut end of the metal wire 14. When the outer layer 17 is present distally of the cut end of the metal wire 14, it is preferable to cut the inner layer 12 and the outer layer 17 distally of the cut end of the metal wire 14. By cutting the tube 31 to be cut after the first laser irradiation with the second laser 42 in this manner, it is possible to prevent the metal wire 14 from protruding from the cut end of the tube 32. It is also possible to prevent the bulge 16 at the end of the metal wire 14 from being cut by the second laser 42. Note that "proximal side of the cut end of the metal wire 14" refers to the side of the reinforcing layer 13 that is closer to the cut end of the metal wire 14 (the side that is removed by cutting) in the tube 31 to be cut after the first laser irradiation. This means that in the cut tube 32, there is a section that has the inner layer 12 and does not have the metal wire 14 at the longitudinal end (the end cut by the second laser 42).

[0054] When cutting with the second laser 42, it is desirable that the cut surface of the tube 32 be as clean as possible. That is, it is desirable that the tube 31 to be cut is melted over a wide area by irradiation with the second laser 42, and that large irregularities are not formed on the cut surface. It is also desirable that the vicinity of the cut end of the tube 32 is not collapsed radially inward. From the viewpoint of cutting the tube 32 in this way, it is preferable to use a pulsed laser as the second laser 42, and more preferably a short-pulse laser. This prevents heat from diffusing from the irradiated area of ​​the second laser 42 to the surrounding area when the tube 31 to be cut is irradiated with the second laser 42, preventing the tube 31 to be cut from melting over a wide area, and allowing the cut surface of the tube 32 to be cleanly formed.

[0055] On the other hand, it is preferable to use a long-pulse laser or a continuous-wave laser as the first laser 41 used in the first laser irradiation step. This allows heat to be transmitted not only to the irradiated portion of the metal wire 14 but also to the surrounding metal wire 14 and outer layer 17 when the first laser 41 is irradiated onto the metal wire 14. As a result, the irradiation of the first laser 41 not only cuts the metal wire 14 but also facilitates heat transfer from the metal wire 14 to melt the outer layer 17. This also makes it easy to form a bulge 16 (molten ball) at the end of the metal wire 14.

[0056] From the above viewpoints, it is preferable to use a pulsed laser as the first laser 41 and a pulsed laser with a narrower pulse width than the first laser 41 as the second laser 42. Alternatively, it is preferable to use a continuous wave laser as the first laser 41 and a pulsed laser as the second laser 42. The pulsed laser used as the first laser 41 is preferably a millisecond pulsed laser or a microsecond pulsed laser. The pulsed laser used as the second laser 42 is preferably a nanosecond pulsed laser, a femtosecond pulsed laser, or a picosecond pulsed laser, and more preferably a femtosecond pulsed laser or a picosecond pulsed laser. A millisecond pulsed laser is a laser with a pulse width of 1 millisecond or more and less than 1 second, a microsecond pulsed laser is a laser with a pulse width of 1 microsecond or more and less than 1 millisecond, a nanosecond pulsed laser is a laser with a pulse width of 1 nanosecond or more and less than 1 microsecond, a femtosecond pulsed laser is a laser with a pulse width of 1 femtosecond or more and less than 1 nanosecond, and a picosecond pulsed laser is a laser with a pulse width of 1 picosecond or more and less than 1 femtosecond.

[0057] Known lasers can be used as the first laser 41 and the second laser 42. There are no particular limitations on the laser medium, and solid-state lasers, liquid lasers, gas lasers, fiber lasers, semiconductor lasers, chemical lasers, free lasers, etc. can be used.

[0058] The cut tube 32 obtained as described above can be used to assemble the catheter 10. For example, as shown in Fig. 1, the catheter 10 can be assembled by using the cut tube 32 as the tube 11 and attaching the operation unit 21 to the proximal side thereof. [Explanation of symbols]

[0059] 10: Catheter 11: Tube 12: Inner layer 13: Reinforcement layer 14: Metal wire, 14A: First metal wire, 14B: Second metal wire 15: Intersection 16: Bulge 17: Outer layer 21:Operation unit 22: Treatment port 23: Fluid injection port 31: Tube to be cut 32: Cutting tube 41: First Laser 42: Second Laser

Claims

1. A catheter comprising a tube having a longitudinal direction extending from a proximal side to a distal side and a radial direction perpendicular to the longitudinal direction, the tube has an inner layer made of resin, a reinforcing layer provided radially outside the inner layer and including a braided first metal wire and a braided second metal wire, and an outer layer made of resin provided radially outside the reinforcing layer, A catheter in which the reinforcing layer has a bulge at the distal end of the first metal wire where the first metal wire is melted, and a bulge at the distal end of the second metal wire where the second metal wire is melted.

2. a thickness of the bulging portion of the first metal wire rod is greater than a thickness of the first metal wire rod other than the bulging portion; The catheter according to claim 1 , wherein the thickness of the bulging portion of the second metal wire is greater than the thickness of the second metal wire other than the bulging portion.

3. A catheter as described in claim 1, wherein an intersection between the first metal wire and the second metal wire is present at the distal end of the reinforcing layer, and at the intersection, the bulge portion of the first metal wire and the bulge portion of the second metal wire are melted and integrated.

4. 4. The catheter according to claim 3, wherein the melting point of the first metal wire is the same as that of the second metal wire.

5. The catheter according to claim 3 , wherein the first metal wire and the second metal wire are made of the same metal.

6. the bulge portion of the first metal wire is covered with the resin of the outer layer from the outer side to the inner side in the radial direction of the first metal wire, A catheter according to any one of claims 1 to 5, wherein the bulge portion of the second metal wire is covered with the outer layer resin from the outside to the inside in the radial direction of the second metal wire.

7. The catheter according to any one of claims 1 to 5, wherein the inner layer extends distally beyond the distal end of the reinforcing layer.

Images