Catheter and method of manufacturing the same

Abstract

To prevent cutting-off of each element wire and to enhance bonding strength of two element wires when bonding braided bodies at an intersection part by laser welding in a catheter and a manufacturing method of the catheter.SOLUTION: A catheter includes a cylindrical braided body 16 which has a first set of metal element wires 17 inclined in an axial direction L and wound around; and a second set of metal element wires 18 which are inclined in the axial direction, wound around and cross the first set of element wires at a plurality of intersections 19. In at least a part of the intersections of the plurality of intersections, two element wires 17, 18 are welded by a weld part 36 formed in an angle area including one of four angles P1a, P2, P3, P4 when seen from an outer peripheral side. The weld part 36 is formed only in a part in a width direction when seen from the outer peripheral side with respect to the element wires on an inner peripheral side.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a catheter and a method for manufacturing a catheter. [Background technology]

[0002] Catheters have traditionally been used for insertion into tubular organs in the body, such as blood vessels. Catheters include structures that include an inner layer, a braided body disposed on the outer periphery of the inner layer, and an outer layer disposed on the outer periphery of the braided body, as well as structures that do not have an inner layer but have a braided body disposed on the inner periphery of the outer layer. The braided body functions as a reinforcing material and is formed by weaving together metal wires such as tungsten or stainless steel. The braided body is composed of a first set of wires wound at an angle relative to the axial direction and a second set of wires wound at an angle relative to the axial direction and intersecting the first set of wires. Patent Document 1 describes a catheter with a braided body disposed between the inner and outer layers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-262625 Summary of the Invention [Problem to be solved by the invention]

[0004] In a braid, metal wires have high rigidity, so there is a possibility that two wires may separate or become misaligned in the circumferential direction at their intersections. For this reason, the wire located on the outer periphery of the braid and the wire located on the inner periphery at the intersections may be welded together. One possible welding method is to irradiate one or both sides of the outer periphery wire with a laser beam to melt the side, and then allow the irradiated energy of the laser beam to penetrate the inner periphery wire through the melted and solidified portion, thereby performing a fillet weld to join the two outer and inner periphery wires.

[0005] However, when joining two wires using such fillet welding, when one or both sides of the outer wire are irradiated with laser light to melt it, the width of the irradiated area of the laser light covers the entire width of the inner wire, so there is a possibility that almost the entire width of the inner wire will be melted by the irradiation energy of the laser light. Furthermore, if the melting depth of the inner wire becomes too large, there is a possibility that the inner wire will be cut. In this case, it is possible to reduce the irradiation energy of the laser light, but this may result in insufficient melting of the outer wire, reducing the joint strength of the two wires and resulting in an insufficient joint between the two wires.

[0006] An object of the present invention is to increase the joining strength of a plurality of wires while avoiding the cutting of the wires when the wires forming a braid are joined at their intersections by laser welding. [Means for solving the problem]

[0007] The catheter of the present invention is a catheter having a tubular braided body including a first set of metallic wires wound at an angle to the axial direction, and a second set of metallic wires wound at an angle to the axial direction and intersecting with the first set of wires at multiple intersections, wherein at least some of the multiple intersections, two of the wires are welded by a weld formed in a corner region including one of four corners when viewed from the outer periphery, and the weld is formed on the inner periphery of the wires only in a portion of the width direction when viewed from the outer periphery.

[0008] According to the above configuration, when forming a welded portion by irradiating a laser beam, the irradiation energy of the laser beam can be prevented from reaching the entire width of the inner wire adjacent to the intersection. This prevents the inner and outer wires from being cut when joining the braid at the intersection by laser welding, eliminating the need to increase the width or thickness of the wires. Furthermore, the setting range of the irradiation energy of the laser beam and the range to be irradiated with the laser beam can be set with more freedom, and the irradiation energy of the laser beam can also be increased, thereby increasing the joining strength of the multiple wires.

[0009] In the catheter according to the present invention, the corner region can be configured to be formed by an outer corner portion that includes one of the four corners of the wire on the outer side of the partial intersection, and a portion of the wire on the inner side that is adjacent to the outer corner portion in at least one of the radial and longitudinal directions.

[0010] In the catheter according to the present invention, the angular region may be located at a portion of the partial intersection where an obtuse angle is formed by the two strands.

[0011] This configuration allows for greater flexibility in determining the irradiation range and position of the laser beam compared to when the corner region is located at the intersection where two strands form an acute angle, which also makes it easier to reduce the area of each strand that is damaged by the laser beam.

[0012] In the catheter according to the present invention, the some of the intersections may be configured to include, among the plurality of intersections, a most distal intersection that is located near a tip end having a cut portion of the braided body.

[0013] According to the above configuration, the two wires can be welded with high joining strength at the most extreme intersection near the tip where the cut portion of the braid is located, even though the two wires are more likely to separate and become misaligned. This makes the effect of welding the two wires at the intersection more pronounced.

[0014] The method for manufacturing a catheter according to the present invention is a method for manufacturing a catheter having a tubular braided body including a first set of metallic wires wound at an angle to the axial direction and a second set of metallic wires wound at an angle to the axial direction and intersecting with the first set of wires at multiple intersections, wherein the method includes a welding step of irradiating a corner region including one of four corners as viewed from the outer periphery with laser light at at least some of the multiple intersections, to melt and solidify the corner region to form a weld, thereby welding the two wires together, and the weld is formed in only a portion of the width of the inner wire as viewed from the outer periphery.

[0015] According to the above configuration, the irradiation energy of the laser beam for forming the welded portion can be prevented from extending over the entire width of the wire on the inner periphery adjacent to the intersection. This prevents the inner and outer periphery wires from being cut when joining the braid at the intersection by laser welding, eliminating the need to increase the width or thickness of the wires. Furthermore, the setting range of the irradiation energy of the laser beam and the range to which the laser beam is irradiated can be set with greater flexibility, and the irradiation energy of the laser beam can be increased, thereby increasing the joining strength of the multiple wires. Furthermore, welding can be performed at least once for each intersection.

[0016] In the method for manufacturing a catheter according to the present invention, the corner region can be configured to be formed by an outer corner portion that includes one of the four corners of the wire on the outer side of the partial intersection, and a portion of the wire on the inner side that is adjacent to the outer corner portion in at least one of the radial and longitudinal directions.

[0017] In the method for manufacturing a catheter according to the present invention, the corner region may be located at a portion of the partial intersection where an obtuse angle is formed by the two wires.

[0018] With this configuration, the irradiation range and position of the laser beam can be set with more freedom than when the corner region is located at a crossing point where two strands form an acute angle, which makes it easier to reduce the area of each strand that is damaged by the laser beam.

[0019] In the method for manufacturing a catheter according to the present invention, the partial intersection portion includes a most distal intersection portion among the plurality of intersection portions that is located near the tip end having the cut portion of the braided body, and the method can be configured to include a cutting step of cutting one or both of the two wires by irradiating them with laser light so as to form the cut portion after welding the two wires at the partial intersection portion in the welding step.

[0020] According to the above configuration, the two wires can be welded with high joining strength at the most extreme intersection near the tip where the cut portion of the braid is located, even though the two wires are more likely to separate and become misaligned. This makes the effect of welding the two wires at the intersection more pronounced. Furthermore, by performing the cutting process after the welding process, the outer wire can be prevented from separating from the inner wire due to cutting, and the order in which the two wires are cut is not limited. This facilitates the cutting operation. [Effects of the Invention]

[0021] According to the catheter and catheter manufacturing method of the present invention, when the wires forming the braided body are joined at their intersections by laser welding, the strength of the joining of the multiple wires can be increased while avoiding the cutting of the individual wires. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are diagrams illustrating a state in which a catheter according to an embodiment is used. [Figure 2] FIG. 2 is an overall view of the catheter shown in FIG. 1. [Figure 3] FIG. 3 is a perspective view showing the catheter shown in FIG. 2 with a portion of the outer layer of the distal shaft peeled off. [Figure 4] FIG. 4 is an enlarged view of part A in FIG. 3. [Figure 5] In the method for manufacturing a catheter of the embodiment, (a) is a schematic diagram showing a welded portion and a planned cutting line before a braided body is cut, and (b) is a schematic diagram showing the tip of the braided body after cutting. [Figure 6] 5(a) is a schematic diagram corresponding to FIG. 4, showing the irradiated portion before a weld is formed on the braided body, and FIG. 5(b) is an enlarged view of the intersection including the irradiated portion of FIG. 5(a). [Figure 7] FIG. 7 is a diagram corresponding to FIG. 6(a) in a first example of a comparative example. [Figure 8] FIG. 5 is a view corresponding to FIG. 4 in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment.

[0024] A guide extension catheter 10, which is a catheter according to one embodiment, will be described using Figures 1 to 6. As shown in Figure 1, the guide extension catheter 10 is used by inserting the lead-out portion of a guiding catheter 100 into a coronary artery 102 and leading a stent delivery catheter 106 from the distal end P of the lead-out portion. In Figure 1, the guiding catheter 100 is shown by the area shaded in black. Hereinafter, the guide extension catheter 10 will be referred to as the catheter 10. Because the catheter 10 is used in the state shown in Figure 1, its distal end P is required to be flexible so that it can be easily inserted into an organ such as a blood vessel.

[0025] FIG. 2 is an overall view of the catheter 10. The catheter 10 is an elongated member comprising a cylindrical distal shaft 12 and a proximal shaft 50 made of a metal wire and connected to the proximal end of the distal shaft 12. The distal end of the proximal shaft 50 is connected to a circumferential portion of the outer circumferential surface of the distal shaft 12. Note that the distal end of the proximal shaft 50 is not limited to being connected to the outer circumferential surface of the distal shaft, and may be disposed, for example, between an inner layer 14 and an outer layer 30 (described below) of the distal shaft 12. In this embodiment, the "proximal end" refers to the rear side (left side in FIG. 2) of the catheter 10 when it is inserted into a blood vessel. The "distal end" refers to the front side (right side in FIG. 2) of the catheter 10 when it is inserted into a blood vessel.

[0026] 3 is a perspective view showing a state in which a portion of the outer layer 30 of the distal shaft 12 of the catheter 10 has been peeled off. The distal shaft 12 includes an inner layer 14 made of resin, a braided body 16 provided on the outer periphery of the inner layer 14, and an outer layer 30 made of resin and provided on the outer periphery of the braided body 16.

[0027] The inner layer 14 forms a lumen 15 for inserting another catheter therein. The resin material constituting the inner layer 14 is not particularly limited, but for example, polytetrafluoroethylene (PTFE) or the like is used. The inner layer 14 is not limited to a single-layer tube, and may be a multi-layer tube made of the same or different materials.

[0028] The braid 16 is a tubular body in which a first set of wires 17 and a second set of wires 18 are woven in a mesh pattern. Specifically, the first set of wires 17 is formed of a plurality of metal wires 17 wound around the outside of the inner layer 14, at an angle along a first direction relative to the axial direction L of the catheter 10. The second set of wires 18 is formed of a plurality of metal wires 18 wound around the outside of the inner layer 14, at an angle along a second direction different from the first direction relative to the axial direction L of the catheter 10, and intersects with the first set of wires 17 at a plurality of intersections 19.

[0029] Each of the first and second sets of wires 17, 18 is a metal wire made of tungsten, stainless steel, etc. The cross section of each of the wires 17, 18 taken orthogonal to the longitudinal direction is rectangular.

[0030] The outer layer 30 covers the outer periphery of the inner layer 14 and the braided body 16. Thus, the outer layer 30 is provided on the outer periphery of the braided body 16. The resin material constituting the outer layer 30 is not particularly limited, but may be, for example, polyether block amide (PEBA), polyethylene (PE), polypropylene (PP), polyamide (PA), polyimide (PI), polyamide-imide (PAI), polyethylene terephthalate (PET), polyurethane (PU), nylon elastomer, polyester elastomer, ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVC), or the like. For example, Pebax® manufactured by Arkema may be used as the resin constituting the outer layer 30. The outer periphery of the outer layer 30 is preferably coated with a hydrophilic material such as hyaluronic acid, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinyl alkyl ether, and maleic anhydride copolymer (VEMA). For example, the hydrophilic coating may be applied only to the portion of the outer layer 30 extending from the distal end P to a predetermined position in the longitudinal middle. The outer layer 30 is not limited to a single-layer tube, but may be a multi-layer tube made of the same or different materials. Furthermore, the hardness of multiple longitudinal portions of the outer layer 30 may be varied. For example, if the outer layer 30 is divided into a distal end, a middle portion, and a proximal end, the hardness of the resin forming the distal end may be the lowest, the hardness of the resin forming the proximal end may be the highest, and the hardness of the resin forming the middle portion may be intermediate between the hardness of the resins at the distal end and the proximal end. This makes the distal end of the outer layer 30 softer, preventing damage to blood vessels and improving blood vessel tracking. Furthermore, the hardness of the proximal end of the outer layer 30 ensures pushability. Furthermore, by making the hardness of the middle portion intermediate between that of the distal end and the proximal end, it is possible to make the middle portion less likely to break even if there is a large difference in hardness between the distal end and the proximal end.

[0031] Furthermore, the distal end of the distal shaft 12 is provided with a distal tip 31 (FIG. 2) formed from a portion of the outer layer 30 and made of resin with radiopaque metal powder mixed in. In FIG. 2, the distal tip 31 is shown as a sandy area at the distal end of the distal shaft 12. For example, bismuth oxide (Bi), tungsten (W), barium sulfate, or the like may be used as the metal powder. By forming the distal tip 31 in this manner by mixing the radiopaque metal powder into the resin of the outer layer 30, the distal end of the distal shaft 12 is made flexible while allowing the operator to easily identify the distal end position of the distal shaft 12 under X-ray fluoroscopy.

[0032] The two wires 17, 18 are welded together at a weld formed in one corner region at at least some of the multiple intersections 19. This will be described in more detail with reference to Figures 4 to 6. The following description will focus on the tip portion of the braid 16 located on the distal end side of the distal shaft 12.

[0033] FIG. 4 is an enlarged view of portion A in FIG. 3. In the example of FIG. 4, of multiple intersections 19 at the tip of the braid 16 located on the distal end side of the distal shaft 12, two wires 17, 18 are welded at the most distal intersection 19 located near the tip having the cut portion 20. A plurality of most distal intersections 19 are present at multiple circumferential positions near the tip of the braid 16. The braid 16 forms approximately diamond-shaped mesh holes at the portion where two adjacent wires 17 of the first set and two adjacent wires 18 of the second set are combined. Furthermore, around each intersection 19, the two wires 17, 18 form two diagonal obtuse angles (angles E1, E2 in FIG. 4) and two diagonal acute angles (angles E3, E4 in FIG. 4).

[0034] The two wires 17, 18 are joined by a weld 36 at the intersection 19 at their leading ends. Specifically, as shown in FIG. 4 , for example, the weld 36 is formed in a corner region including a first angle P1a among the four corners P1a, P2, P3, and P4 of the outer wire 17. The corner region is formed by the outer wire corner portion including the first angle P1a among the four corners P1a, P2, P3, and P4 of the outer wire 17 at the leading end intersection 19, and a portion of the inner wire 18 adjacent to the outer wire corner portion in at least one of the radial and longitudinal directions. In FIG. 6( b ), which will be described later, the outer wire corner portion including the first angle P1a is indicated by a horizontal stripe Q1 before the weld 36 is formed, and the portion of the inner wire 18 adjacent to the outer wire corner portion in the longitudinal direction is indicated by a vertical stripe Q2. In FIG. 4 , the weld 36 is indicated by a sandy area. The weld 36 is formed by melting an outer corner portion and a portion of the inner wire 18 adjacent to the outer corner portion, which then mix and solidify. The two wires 17, 18 are welded together by this weld 36. Furthermore, the weld 36 is formed only in a portion of the inner wire 18 in the direction along the boundary line M with the most distal intersection 19 when viewed from the outer periphery, as shown in FIG. 4 , but not along the entire direction along this boundary line M. As a result, the weld 36 is formed only in a portion of the inner wire 18 in the width direction when viewed from the outer periphery. Therefore, when the braid 16 is joined at the intersection 19 by laser welding, as described below, it is possible to prevent the wires 17, 18 from being cut and to increase the joining strength of the two wires 17, 18.

[0035] Furthermore, the corner region forming the weld 36 is located at the portion of the intersection 19 at the most distal end where the two strands 17, 18 form an obtuse angle E1.

[0036] Next, a method for manufacturing the catheter 10 will be described with reference to Figures 5 and 6. Figure 5(a) is a schematic diagram showing the welded portion and the planned cutting line before the cutting step of the braided body 16, and (b) is a schematic diagram showing the distal end of the braided body 16 after cutting, in a method for manufacturing a catheter according to an embodiment. Figure 6(a) is a schematic diagram corresponding to Figure 4, showing an irradiated portion 38 before a welded portion is formed in the braided body 16, and Figure 6(b) is an enlarged view of an intersection 19 including the irradiated portion 38 in Figure 6(a).

[0037] First, an "arranging step" is performed in which the braid 16 is arranged on the cylindrical surface 14a, which is the outer peripheral surface of the inner layer 14. At this time, the inner layer 14 may be extruded into a long cylindrical shape using an extruder or the like, using a resin material, onto a metal core wire or onto a shaft portion having a cylindrical outer peripheral surface that constitutes a jig. A braiding machine may be used to arrange the braid 16 on the outer periphery of the inner layer 14. The braiding machine winds a first set of multiple wires 17 around the cylindrical surface 14a of the inner layer 14 in a first direction that is inclined with respect to the axial direction of the inner layer 14, and winds a second set of multiple wires 18 around the cylindrical surface 14a of the inner layer 14 in a second direction that is inclined with respect to the axial direction of the inner layer 14 and intersects the first direction. At this time, the braid 16 is arranged so as to extend almost to the tip of the inner layer 14.

[0038] Next, a "welding process" is performed. In the welding process, two wires 17, 18 are welded by irradiating a laser beam onto intersection 19, which is the most distal intersection and is a plurality of intersections arranged in a row along the circumferential direction on the lower side of FIG. 5(a), adjacent to the planned cutting line indicated by the dashed line in FIG. 5(a). At this time, the laser beam is irradiated onto a corner region including one corner on the axial center side of braided body 16, out of the four corners of intersection 19 to be irradiated with the laser. In FIGS. 5(a) and 5(b), the laser beam irradiation region is indicated by a plurality of unfilled circles.

[0039] More specifically, as shown in Fig. 6, the intersection 19 before being irradiated with the laser light is a rhombus having four corners P1, P2, P3, and P4. The laser light is irradiated to an irradiation region (within a circle H in Fig. 6(a)) so as to irradiate an outer circumferential corner portion, including corner P1, which is located at the axial center of the braid 16, among the four corners P1, P2, P3, and P4 of the intersection 19, and an irradiated portion 38 formed by the outer circumferential corner portion and a longitudinally adjacent portion of the inner circumferential wire 18. As a result, the portions of the two wires 17, 18 included in the irradiated portion 38 and the radially adjacent portion of the inner circumferential wire 18 to the outer circumferential corner portion are melted and solidified to form a weld 36 (Fig. 4), and the two wires 17, 18 are joined by the weld 36. Therefore, the corner region that forms the weld 36 is formed by the outer peripheral corner portion of the outer peripheral wire 17, which includes the first angle P1a of the intersection 19, and the portion of the inner peripheral wire 18 that is adjacent to the outer peripheral corner portion in both the radial and longitudinal directions. However, the corner region may also be formed by the outer peripheral corner portion and the portion of the inner peripheral wire 18 that is adjacent to the outer peripheral corner portion in only one of the radial and longitudinal directions.

[0040] As described above, the irradiation area is irradiated with laser light, and the outer and inner wires 17 and 18 are integrated by partially melting and liquefying them and then solidifying. In this example, only a portion of the inner wire 18 melts in the width direction, eliminating the need to consider the risk of cutting the inner wire 18. Therefore, the corner area can be irradiated with a high laser beam irradiation energy. This increases the amount of melting of the two wires 17 and 18 irradiated with the laser beam. When the molten wires 17 and 18 solidify to form the weld 36, the two wires 17 and 18 are more likely to be strongly joined at the weld 36. Furthermore, because the welds of the wires 17 and 18 do not extend across the entire width of each wire, cutting of the wires 17 and 18 is prevented. The above describes a case where two wires 17, 18 are joined by a welding portion 36 at an intersection 19 where a first set of wires 17 is arranged on the outer periphery and a second set of wires 18 is arranged on the inner periphery. However, even at an intersection 19 where a second set of wires 18 is arranged on the outer periphery and a first set of wires 17 is arranged on the inner periphery, the two wires 17, 18 can be joined in the same way by a welding portion 36, with the positions simply reversed.

[0041] After the "welding step," a "cutting step" is performed. In the "cutting step," the braid 16 is cut along the cutting line indicated by the dashed line in FIG. 5(a). At this time, of the two wires 17, 18 extending in two directions from each of the intersections at the most distal ends where the welds are formed toward the tip, the portions close to the intersection 19 where the welds are formed are cut by irradiating them with laser light. Specifically, in FIG. 5(a), the wires 17, 18 along the cutting line are irradiated with laser light. In FIG. 5(a), the cut portions of the first set of wires 17 are indicated by black circles, and the cut portions of the second set of wires 18 are indicated by black squares. By irradiating the wires 17, 18 along the cutting line with laser light, the irradiated portions melt, and the corresponding wires 17, 18 are cut by this melting. This results in the braid 16 cut along the cutting line, as shown in FIG. 5(b). Then, the excess portion distal to the cutting line is removed. Therefore, the intersection 19 where the welded portion of the braid 16 in FIG. 5(a) is formed becomes the most distal intersection 19 near the tip having the cut portion 20 in the braid 16 in FIG. 5(b).

[0042] In the "cutting step," excess wire is removed, and then an outer layer 30 made of resin is molded around the braid 16 and the inner layer 14 to form the distal shaft 12. The proximal shaft 50 is then joined to the distal shaft 12 to form the catheter 10.

[0043] According to the catheter 10 and its manufacturing method, the two wires 17, 18 are welded together by a weld 36 formed in a corner region including one of the four corners of the intersection 19 at the tip. Furthermore, the weld 36 is formed on only a portion of the inner wire in the width direction when viewed from the outer periphery. This prevents the laser beam energy from reaching the entire width of the inner wire adjacent to the intersection 19 when the weld 36 is formed by laser beam irradiation. This prevents the inner and outer wires 17, 18 from being cut when the braid 16 is joined at the intersection 19 by laser welding, eliminating the need to increase the width or thickness of the wires. Furthermore, the range of laser beam irradiation energy and the range of laser beam irradiation can be set with greater flexibility, and the laser beam irradiation energy can be increased, thereby increasing the joining strength of the two wires 17, 18. This makes it possible to increase the bonding strength of the multiple wires 17, 18 while avoiding cutting of each of the wires 17, 18. Furthermore, according to the above-described method for manufacturing the catheter 10, it is possible to complete the welding operation for one intersection 19 at least once.

[0044] Furthermore, the corner region where the weld 36 is formed is located in a portion of the intersection 19 where the two wires 17, 18 form an obtuse angle. This allows for greater flexibility in determining the irradiation range and position of the laser beam compared to when the corner region where the weld is formed is located in a portion where the two wires form an acute angle. This also makes it easier to reduce the area of each wire 17, 18 that is damaged by the laser beam. In this example, of the two corners P1a, P3 that form obtuse angles at the most distal intersection, the two wires 17, 18 are welded in the corner region on the side of corner P1a, opposite the cut portion 20 of each wire 17, 18. On the other hand, of the two corners P1a, P3 that form obtuse angles at the most distal intersection, the two wires 17, 18 may be welded in the corner region on the side of corner P3, which is on the same side as the cut portion 20 of each wire 17, 18.

[0045] Furthermore, the intersection 19 where the weld 36 is formed is the most distal intersection 19 of the multiple intersections 19, located near the tip of the braided body 16 where the cut portion 20 is located. As a result, at the most distal intersection near the tip of the braided body 16 where the cut portion 20 is located, the two elemental wires 17, 18 are more likely to separate and become misaligned, but the two elemental wires 17, 18 can be welded with high joining strength. This makes the effect obtained by welding the two elemental wires 17, 18 at the intersection 19 more pronounced.

[0046] Furthermore, according to the catheter manufacturing method of this example, after welding the two wires at intersection 19 in the welding step, a cutting step is performed in which both of the two wires 17, 18 are cut by irradiating them with laser light to form cut portion 20. This prevents the wire on the outer periphery of the intersection from separating from the wire on the inner periphery due to cutting, and does not restrict the order of cutting when both wires are cut near the intersection. Specifically, when two wires are not welded at the intersection but are cut adjacent to the intersection, the order of cutting is restricted so that the wire on the inner periphery at the intersection is cut after the wire on the outer periphery. This is because if the cutting order were reversed, the outer periphery wire would be less pressed against the inner periphery, making it easier for the outer periphery wire to separate from the inner periphery wire at the intersection. On the other hand, according to the manufacturing method of this example, the order of cutting is not restricted, which facilitates the cutting operation. After welding the two wires at the intersection in the welding step, a cutting step may be performed in which only one of the two wires 17, 18 is cut by irradiating it with laser light to form cut portions. In this case, for example, the intersections having cut portions may be arranged alternately in the first and second axial rows around the circumferential direction of the braid.

[0047] FIG. 7 is a diagram corresponding to FIG. 6 of a first comparative example. In the first comparative example, two wires 17, 18 on the outer and inner sides are joined by fillet welding at an intersection 19. Specifically, at the intersection 19, a laser beam is irradiated onto both widthwise sides of the outer wire 17, which are circular regions indicated by T1 and T2 in FIG. 7, to melt the both sides, and the irradiation energy of the laser beam penetrates into the inner wire 17 through the melted and solidified portion. This joins the two wires 17, 18 forming the intersection 19. At this time, for example, as shown in FIG. 7, the center of the irradiation region is positioned approximately at the longitudinal center of both widthwise ends of the outer wire 17 at the intersection 19. Furthermore, the width of the laser beam irradiated area covers almost the entire width of each wire 17, 18. As a result, the entire width of the outer peripheral side surface 18a of the inner wire 18 forming the intersection 19, which is adjacent to the intersection 19 in the longitudinal direction of the wire 18, may be melted by the irradiation energy of the laser light. As a result, in the first comparative example, if the melting depth of the inner wire 18 forming the intersection 19 becomes large, the inner wire 18 may be cut in the width direction near the intersection 19. On the other hand, in the first comparative example, if the irradiation energy of the laser light is reduced, the risk of cutting the inner wire 18 can be reduced, but the outer wire 17 may not be melted sufficiently, which may reduce the joint strength between the two wires 17, 18 and result in insufficient joint between the two wires 17, 18. According to the embodiment, such a disadvantage can be resolved.

[0048] Although not shown, as another example of the embodiment, at least one of the first and second sets of wires forming the braid may be a wire with a circular cross section. In this case, the two wires are laser-welded by irradiating a laser beam from the outer periphery to the intersection. In this case, as in the embodiment of FIGS. 1 to 6 , cutting of each wire is avoided while the bonding strength of the multiple wires is increased. Furthermore, even when circular wires are used, the amount of melting of the wires can be approximately the same as when only wires with rectangular cross sections are used, so the welding strength can be increased to the same extent as in a configuration using only wires with rectangular cross sections. Furthermore, when wires with circular cross sections are used as the outer periphery wires, the side portions of the outer periphery wires can be significantly reduced in the width direction. Therefore, compared to the first example of the comparative example, a large gap is less likely to form between the inner circumferential side surface of the outer circumferential wire with circular cross section at the welded portion and the outer circumferential side surface of the inner circumferential wire.

[0049] In each of the above-described embodiments, the braid 16 has only the most distal intersections 19, 19a located near the distal end of the braid, where the two wires are welded. However, the two wires 17, 18 may be welded in corner regions at other intersections in addition to the most distal intersections 19, 19a. For example, the distal end of the braid 16 may have two or more rows of intersections spaced apart in the axial direction L, where the two wires are welded in corner regions. This increases the rigidity of the braid 16 at the distal end. The rigidity of the multiple regions may be varied by varying the number of intersections where two wires are welded in corner regions in multiple regions spaced apart in the axial direction L of the braid.

[0050] Furthermore, in each example of the above embodiment, the two wires are welded in a corner region that includes only one of the two corners P1a, P3 that form an obtuse angle at the intersection, but the two wires may also be welded in a corner region that includes only one of the two corners P2, P4 that form an acute angle at the intersection.

[0051] FIG. 8 is a diagram corresponding to FIG. 4 and shows another example of the embodiment. Unlike the configurations shown in FIGS. 1 to 6, in this example, two wires 17, 18 are welded together at four corner regions at the intersection 19 at the very tip, via welds 36a to 36d. Each corner region is formed by an outer circumferential corner portion including one of the four corners P1a, P2, P3, and P4 of the outer circumferential wire 17 and a portion of the inner circumferential wire 18 adjacent to the outer circumferential corner portion in at least one of the radial and longitudinal directions. The welds 36a to 36d are then formed in the four corner regions. In FIG. 8, the welds 36a to 36d are shown as sandy areas. The two wires 17, 18 are welded together at these four welds 36a to 36d. Furthermore, the welds 36a-36d are formed on the wires 18 on the inner periphery only in a portion of the direction along the boundary lines M1 and M2 with the intersection 19 when viewed from the outer periphery as shown in Fig. 8, and are not formed all along the direction along these boundary lines M1 and M2. As a result, the welds 36a-36d are formed only in a portion of the width direction of the wires 18 on the inner periphery. While the above describes the intersection 19 where the wires 17 are arranged on the outer periphery and the wires 18 are arranged on the inner periphery, the same applies to the intersection 19 where the wires 18 are arranged on the outer periphery and the wires 17 are arranged on the inner periphery.

[0052] In this example, unlike the above-described embodiments, the two wires 17, 18 are welded at the intersection 19 by welds 36a-36d formed in the four corner regions, thereby increasing the weld strength. Furthermore, the strength against forces acting from multiple directions to separate the two wires 17, 18 can be increased. In this example, the other configurations and functions are the same as those in FIGS. 1-6.

[0053] In this example, the two wires 17, 18 are welded by welds 36a-36d formed in four corner regions of one intersection 19, but the two wires 17, 18 may be welded by welds formed in only two or only three of the four corner regions. Also, by varying the number of welds depending on the position of intersection 19, the rigidity of the braid can be varied.

[0054] In each of the above-described embodiments, the catheter of the present invention and the catheter manufactured by the manufacturing method of the present invention are described as guide extension catheters, but the present invention is not limited to this, and various catheters having a braided body on the inside of the outer layer can also be used. [Explanation of symbols]

[0055] 10 guide extension catheter (catheter), 12 distal shaft, 14 inner layer, 14 cylindrical surface, 15 lumen, 16 braided body, 17, 18 wire, 18a outer surface, 19 intersection, 20 cut portion, 21 wire, 22 gap, 30 outer layer, 31 distal tip, 36, 36a to 36d welded portion, 38 irradiation portion, 50 proximal shaft, 100 guiding catheter, 102 coronary artery, 106 stent delivery catheter.

Claims

1. A catheter comprising a tubular braid including a first set of metallic wires wound at an angle to an axial direction, and a second set of metallic wires wound at an angle to the axial direction and intersecting the first set of wires at multiple intersections, At least some of the plurality of intersections are welded to each other by a weld formed in a corner region including one of four corners when viewed from the outer periphery, The welded portion is formed on only a part of the wire on the inner circumferential side in the width direction when viewed from the outer circumferential side, the corner region is located at a portion where an obtuse angle is formed by the two wires at the partial intersection, the some of the intersections includes a most distal intersection among the plurality of intersections, the most distal intersection being arranged near a tip end of the braided body having a cut portion, The corner region is one of two corners where an obtuse angle is formed at an intersection of the leading ends of the two wires, and the corner region is the corner region on the corner side opposite to the leading ends of the two wires. catheter.

2. The catheter of claim 1, The corner region is formed by an outer circumferential corner portion including one of four corners of the wires on the outer circumferential side of the partial intersection, and a portion of the wires on the inner circumferential side adjacent to the outer circumferential corner portion in at least one of the radial direction and the longitudinal direction. catheter.

3. A method for manufacturing a catheter having a tubular braid including a first set of metallic wires wound at an angle to an axial direction, and a second set of metallic wires wound at an angle to the axial direction and intersecting the first set of wires at a plurality of intersections, a welding process in which a corner region including one of four corners as viewed from an outer periphery of at least some of the plurality of intersections is irradiated with laser light to melt and solidify the corner region to form a weld, thereby welding the two wires together, The welded portion is formed on only a part of the wire on the inner circumferential side in the width direction when viewed from the outer circumferential side, the corner region is located at a portion where an obtuse angle is formed by the two wires at the partial intersection, the some of the intersections includes a most distal intersection among the plurality of intersections, the most distal intersection being arranged near a tip end of the braided body having a cut portion, The corner region is one of two corners where an obtuse angle is formed at an intersection of the leading ends of the two wires, and the corner region is the corner region on the corner side opposite to the leading ends of the two wires. A method for manufacturing a catheter.

4. In the method for manufacturing a catheter according to claim 3, The corner region is formed by an outer circumferential corner portion including one of four corners of the wires on the outer circumferential side of the partial intersection, and a portion of the wires on the inner circumferential side adjacent to the outer circumferential corner portion in at least one of the radial direction and the longitudinal direction. catheter.

5. A method for manufacturing a catheter according to claim 3 or claim 4, the some of the intersections includes a most distal intersection among the plurality of intersections, the most distal intersection being arranged near a tip end of the braided body having a cut portion, a cutting step of cutting one or both of the two wires by irradiating them with laser light so as to form the cut portion after welding the two wires at the partial intersection portion in the welding step; A method for manufacturing a catheter.

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