Catheter

Abstract

Provided is a catheter in which the tip of a distal-end part is less likely to detach. This catheter has a first cylindrical member that extends in the longitudinal direction, a second cylindrical member that extends in the longitudinal direction and is adjacent to the first cylindrical member in the radial direction, an outer member that extends in the longitudinal direction and has a portion encompassing at least part of the first cylindrical member and at least part of the second cylindrical member, and a tip that is disposed at a distal-end part of the second cylindrical member and extends in the longitudinal direction, wherein the distal end of the first cylindrical member is positioned closer to the proximal side than the distal end of the second cylindrical member, the proximal end of the first cylindrical member is positioned closer to the proximal side than the proximal end of the second cylindrical member, the tip has a protrusion that protrudes in a direction away from the central axis of the tip, and the outer member covers at least part of the protrusion.

Description

catheter

[0001] The present invention relates to a catheter.

[0002] Catheters that can be inserted into blood vessels or the like are used to examine and treat lesions in the human body. For example, Patent Document 1 discloses such a catheter, which comprises a catheter body having a hollow coil body formed by winding or twisting together a plurality of metal wires, at least one of which has a diameter larger than the diameters of the other wires, an inner resin layer that covers the inner circumferential surface of the coil body, and an outer resin layer that covers the outer circumferential surface of the coil body in a substantially circular shape without exposing the outer surfaces of the wires with a larger diameter of the coil body to the outside, and a resin tubular body provided at the distal end of the catheter body, which has an inner hole communicating with the hollow part of the catheter body. The catheter is characterized by including a tip, an inner layer extension portion in which the inner resin layer extends integrally from the distal end of the catheter body toward the tip side to form the inner peripheral portion of the proximal end of the tip, and a braided body formed by braiding a plurality of wires, the braided body being positioned so as to extend in the axial direction across the boundary between the proximal end of the tip and the distal end of the catheter body, and being disposed in the inner layer extension portion within the tip and in the inner resin layer of at least the distal end portion of the catheter body.

[0003] JP 2011-125737 A

[0004] The tip disposed at the distal end of conventional catheters has sometimes become detached when the catheter is inserted into or removed from the body. The present invention has been made in consideration of the above circumstances, and its object is to provide a catheter in which the tip at the distal end is less likely to become detached.

[0005] Catheters according to embodiments of the present invention that can solve the above problems are as follows: [1] A catheter having a first tubular member extending in a longitudinal direction, a second tubular member extending in the longitudinal direction and radially adjacent to the first tubular member, an outer member extending in the longitudinal direction and having a portion that contains at least a portion of the first tubular member and at least a portion of the second tubular member, and a tip extending in the longitudinal direction that is disposed at a distal end of the second tubular member, wherein the distal end of the first tubular member is located proximal to the distal end of the second tubular member, the proximal end of the first tubular member is located proximal to the proximal end of the second tubular member, and the tip has a protruding portion that protrudes in a direction away from a central axis of the tip, and the outer member covers at least a portion of the protruding portion.

[0006] As described above, the protrusion that protrudes away from the central axis of the tip is covered by the outer member, making it difficult for the tip located at the distal end to become detached from the catheter.

[0007] Furthermore, the catheter according to the embodiment is preferably any one of the following [2] to

[15] . [2] The catheter according to [1], wherein the distal end of the outer member is located distal to the thickest portion of the protruding portion. [3] The catheter according to [1], wherein the distal end of the outer member is located distal to the distal end of the protruding portion. [4] The catheter according to any one of [1] to [3], wherein the distal end of the outer member is located proximal to the distal end of the second tubular member. [5] The catheter according to any one of [1] to [4], wherein the protruding portion is located at the proximal end of the tip. [6] The catheter according to any one of [1] to [5], wherein the tip has, in the radial direction, a first region closer to the first tubular member and a second region farther from the first tubular member, and the first region has the protruding portion. [7] The catheter according to any one of [1] to [6], wherein the tip is fixed to the second tubular member and not fixed to the outer member. [8] The catheter according to any one of [1] to [7], wherein the tip has metal powder at least on the outer surface covered by the outer member. [9] The catheter according to any one of [1] to [8], wherein the tip has an inner lumen extending in the longitudinal direction, and at least the distal end of the second tubular member is disposed within the lumen.

[10] The catheter according to [9], wherein the diameter of the inner lumen of the tip distal to the distal end of the second tubular member is greater than or equal to the inner diameter of the second tubular member at the distal end of the second tubular member.

[11] The catheter according to any one of [1] to

[10] , wherein the tip has a first thin-walled portion located distal to the protruding portion and thinner than the protruding portion, and a first thick-walled portion located distal to the first thin-walled portion and thicker than the first thin-walled portion.

[12] A catheter described in any of [1] to

[11] , wherein the outer member is tubular and has an inner cavity extending in the longitudinal direction, and at least a portion of the first tubular member and at least a portion of the second tubular member are disposed in the inner cavity.

[13] The catheter according to any one of [1] to

[11] , wherein the outer member has a columnar body extending in the longitudinal direction and containing resin, and at least a portion of the first tubular member and at least a portion of the second tubular member are disposed within the columnar body.

[14] The catheter according to any one of [1] to

[13] , wherein the first tubular member and the second tubular member are fixed to each other in the radial direction.

[15] The catheter according to any one of [1] to

[14] , wherein a handle portion is disposed at a proximal end of the first tubular member.

[0008] According to the present invention, the above-described configuration makes it possible to provide a catheter in which the tip at the distal end is unlikely to come off.

[0009] FIG. 1 is a side view of a catheter according to a first embodiment. FIG. 2 is a longitudinal cross-sectional view of region R1 in FIG. 1. FIG. 3 is a longitudinal cross-sectional view of region R2 in FIG. 1. FIG. 4 is a longitudinal cross-sectional view of a modified example of region R1 in FIG. 1. FIG. 5 is a longitudinal cross-sectional view of another modified example of region R1 in FIG. 1. FIG. 6 is a cross-sectional view taken along line A-A of the catheter in FIG. 1. FIG. 7 is a side view of a catheter according to a second embodiment. FIG. 8 is a longitudinal cross-sectional view of region R1 in FIG. 7. FIG. 9 is a longitudinal cross-sectional view of region R2 in FIG. 7. FIG. 10 is a cross-sectional view taken along line A-A of the catheter in FIG. 7.

[0010] The present invention will be described in more 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. Note that, for convenience, component reference numerals may be omitted in the drawings. In such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to helping understand the features of the present invention.

[0011] The catheter of this embodiment has a first tubular member extending in the longitudinal direction, a second tubular member extending in the longitudinal direction and radially adjacent to the first tubular member, an outer member extending in the longitudinal direction and having a portion that contains at least a portion of the first tubular member and at least a portion of the second tubular member, and a tip extending in the longitudinal direction that is arranged at the distal end of the second tubular member, wherein the distal end of the first tubular member is located proximal to the distal end of the second tubular member, the proximal end of the first tubular member is located proximal to the proximal end of the second tubular member, the tip has a protruding portion that protrudes in a direction away from the central axis of the tip, and the outer member covers at least a portion of the protruding portion.

[0012] As described above, the protrusion that protrudes away from the central axis of the tip is covered by the outer member, making it difficult for the tip located at the distal end to become detached from the catheter.

[0013] A catheter according to a first embodiment will be described below with reference to Figures 1 to 6. Figure 1 is a side view of the catheter according to the embodiment. Figure 2 is a longitudinal cross-sectional view of region R1 in Figure 1. Figure 3 is a longitudinal cross-sectional view of region R2 in Figure 1. Figure 4 is a longitudinal cross-sectional view of a modified example of region R1 in Figure 1. Figure 5 is a longitudinal cross-sectional view of another modified example of region R1 in Figure 1. Figure 6 is a cross-sectional view taken along line A-A of the catheter in Figure 1.

[0014] As shown in FIGS. 1 , 2 , and 3 , the catheter 91 according to the first embodiment includes a first tubular member 1 extending in the longitudinal direction X and a second tubular member 2 extending in the longitudinal direction X and adjacent to the first tubular member 1 in the radial direction Y. Specifically, the outer surfaces of the first tubular member 1 and the second tubular member 2 are preferably adjacent to each other in the radial direction Y. The first tubular member 1 preferably has a lumen 1L extending in the longitudinal direction X. The second tubular member 2 preferably has a lumen 2L extending in the longitudinal direction X. By inserting, for example, a guidewire into each of the lumen 1L and the lumen 2L, the catheter 91 can be guided in multiple directions, thereby facilitating insertion of the catheter 91 into various branching portions of the coronary artery, for example. Furthermore, by inserting a searching wire into the lumen 1L or the lumen 2L, it is possible to easily search for the entrance of a stenotic lesion, for example. Of these, it is preferable to insert the searching wire into the lumen 1L. The tip of the probe wire may be bent.

[0015] As shown in FIG. 2 , the catheter 91 further includes an outer member 3 extending in the longitudinal direction X and having a portion enclosing at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2, and a tip 7 disposed at the distal end 2b of the second tubular member 2 and extending in the longitudinal direction X. The tip 7 has a protrusion 7P protruding in a direction away from the central axis 7C of the tip 7, and the outer member 3 covers at least a portion of the protrusion 7P. Covering the protrusion 7P with the outer member 3 makes the tip 7 less likely to detach from the second tubular member 2. Examples of the shape of the protrusion 7P include a cone, a polygonal pyramid, a rounded polygonal pyramid, a truncated cone, a polygonal pyramid, a rounded polygonal pyramid, a hemisphere, a semi-elliptical sphere, or a combination thereof. The shape of the outer edge of the tip 7 in a cross section in the radial direction Y including the protrusion 7P of the tip 7 is preferably circular or elliptical. This facilitates insertion of the tip 7 into the body. The tip 7 may have multiple protrusions 7P, but preferably has only one protrusion 7P. The shape of the outer edge of the tip 7 in a cross section in the radial direction Y of the portion of the tip 7 that does not include the protrusion 7P is preferably circular or elliptical. This makes it easier to insert the tip 7 into the body.

[0016] The protrusion 7P is preferably located at the proximal end 7a of the tip 7. This makes it even more difficult for the tip 7 to detach from the second tubular member 2. The protrusion 7P is preferably located adjacent to the proximal end 7A of the tip 7. Furthermore, the distal end 7PB of the protrusion 7P is preferably located proximal to the midpoint of the central axis 7C of the tip 7.

[0017] The tip 7 has a first region 71 closer to the first cylindrical member 1 in the radial direction Y and a second region 72 farther from the first cylindrical member 1, and the first region 71 preferably has a protrusion 7P. The side of the tip 7 closer to the first cylindrical member 1 in the radial direction Y is a portion that is less likely to come into contact with body tissue due to the length of the diameter of the first cylindrical member 1, so by arranging the protrusion 7P in the first region 71, the protrusion 7P is less likely to come into contact with body tissue. As a result, the tip 7 can be more easily and smoothly inserted into the body.

[0018] As shown in FIG. 2 , when a cross section X is defined as a cross section in the longitudinal direction X including the central axis 1C of the first tubular member 1 and the central axis 2C of the second tubular member 2, the protruding portion 7P preferably has a proximal inclined portion that inclines away from the central axis 7C of the tip 7 as it moves distally, and a distal inclined portion that is located distal to the proximal inclined portion and inclines toward the central axis 7C of the tip 7 as it moves distally. The distal inclined portion makes it easier to insert the tip 7 into the body. The proximal inclined portion increases the contact area between the tip 7 and the outer member 3. The outer surfaces of the proximal inclined portion and the distal inclined portion in the cross section X are preferably linear or curved, and more preferably linear. For example, if the outer surface of the distal inclined portion in the cross section X is linear, the distal inclined portion has a tapered shape.

[0019] The tip 7 is preferably fixed to the second cylindrical member 2. This makes it even more difficult for the tip 7 to detach from the second cylindrical member 2. Specifically, it is preferable that at least a portion of the inner surface of the tip 7 is fixed to the outer surface of the second cylindrical member 2. Examples of the manner of fixing include welding and adhesion. Although not shown, another layer may be disposed between the tip 7 and the second cylindrical member 2, and the tip 7, the other layer, and the second cylindrical member 2 may be welded or adhered together.

[0020] It is preferable that the tip 7 is not fixed to the outer member 3. This makes it difficult for external forces applied to the outer member 3 near the protruding portion 7P to act on the protruding portion 7P, making it difficult to avoid detachment of the tip 7 due to external forces.

[0021] On the other hand, the tip 7 may be fixed to the outer member 3. In this way, even if the tip 7 and the second cylindrical member 2 are separated by, for example, an external force, the outer member 3 can prevent the tip 7 from detaching from the second cylindrical member 2. Specifically, at least a portion of the outer surface of the tip 7 may be fixed to the inner surface of the outer member 3. Examples of the fixing method include welding and bonding. Although not shown, another layer may be disposed between the tip 7 and the outer member 3, and the tip 7, the other layer, and the outer member 3 may be welded or bonded together.

[0022] The tip 7 preferably has metal powder at least on the outer surface covered by the outer member 3. This allows for the formation of irregularities on the outer surface of the tip 7, which improves friction when the tip 7 and the outer member 3 are not fixed to each other, and improves fixing force when the tip 7 and the outer member 3 are fixed to each other. As a result, the tip 7 is less likely to come off. Examples of metal powder include tungsten powder. Alternatively, powder of an X-ray opaque material, which will be described later, may be used as the metal powder.

[0023] The tip 7 preferably contains a flexible resin, which can reduce damage to internal tissues caused by inserting the tip 7 into the body. The flexible resin preferably contains at least one selected from the group consisting of polyethylene, polyurethane, polyurethane-based thermoplastic elastomer, styrene-based thermoplastic elastomer, polyamide elastomer, and polyamide, and more preferably contains at least one selected from the group consisting of polyurethane and polyamide elastomer. The polyethylene is preferably low-density polyethylene having a specific gravity of 0.91 to 0.92.

[0024] The tip 7 preferably contains a flexible resin and metal powder, and more preferably contains a mixture of flexible resin and metal powder. For example, when a radiopaque material is used as the metal powder, the radiopaque material is dispersed in the flexible resin, which makes the tip 7 more radiopaque and easier to observe from outside the body.

[0025] The tip 7 preferably has a lumen 7L extending in the longitudinal direction X, and at least the distal end 2B of the second tubular member 2 is disposed within the lumen 7L. This allows at least a portion of the inner surface of the tip 7 to be fixed to the outer surface of the second tubular member 2. In the cross section of the tip 7 in the radial direction Y, the shape of the lumen 7L is preferably circular or elliptical. This makes it easier to fix at least a portion of the inner surface of the tip 7 to the outer surface of the second tubular member 2.

[0026] The diameter of the lumen 7L of the tip 7 distal to the distal end 2B of the second tubular member 2 is preferably larger than or the same as the inner diameter of the second tubular member 2 at the distal end 2B of the second tubular member 2. As shown in Fig. 2, having these lengths is the same, allowing the guidewire to be smoothly inserted into the second tubular member 2. On the other hand, as shown in Fig. 4, the diameter of the lumen 7L distal to the distal end 2B is larger than the inner diameter of the second tubular member 2 at the distal end 2B, making it less likely for the guidewire to come into contact with the inner surface of the tip 7 when inserting the guidewire into the lumen 7L, thereby making it easier to prevent detachment of the tip 7 due to friction with the guidewire.

[0027] The tip 7 preferably has a first thin portion 7U1 located distal to the protruding portion 7P and thinner than the protruding portion 7P, and a first thick portion 7T1 located distal to the first thin portion 7U1 and thicker than the first thin portion 7U1. This allows the tip 7 to bend around the first thin portion 7U1 when inserted into a curved portion such as a blood vessel inside the body, and the first thick portion 7T1 makes it easier to prevent the tip 7 from bending excessively.

[0028] The distal end 7B of the tip 7 is preferably located distal to the distal end 2B of the second tubular member 2. By positioning the tip 7 made of a flexible material in this manner, it is possible to improve the flexibility of the portion of the tip 7 distal to the distal end 2B of the second tubular member 2. The portion of the tip 7 distal to the distal end 2B of the second tubular member 2 preferably includes a first thick portion 7T1, and more preferably consists of the first thick portion 7T1.

[0029] 2 , as described above, the catheter 91 further includes an outer member 3 that extends in the longitudinal direction X and has a portion that contains at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2. The outer member 3 can protect the first tubular member 1 and the second tubular member 2, and can also easily prevent the guide wire from breaking through from inside the catheter 91.

[0030] As shown in Figures 2, 3, and 6, in the catheter 91, the outer member 3 is cylindrical and has a lumen 3L extending in the longitudinal direction X. Preferably, at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2 are disposed in the lumen 3L. This protects the first tubular member 1 and the second tubular member 2, and the gaps between the outer member 3 and the first tubular member 1 and the gaps between the outer member 3 and the second tubular member 2 allow each tubular member to move to some extent, thereby dissipating the force of the guidewire from inside the catheter 92 and making it easier to prevent the guidewire from breaking through. The distal end of the cylindrical outer member 3 is preferably fixed to the first tubular member 1 and the second tubular member 2. The proximal end of the cylindrical outer member 3 is preferably fixed to the first tubular member 1 and the second tubular member 2. This makes the cylindrical outer member 3 less likely to kink or twist.

[0031] The outer member 3 preferably contains at least one selected from the group consisting of polyethylene, polyurethane, polyurethane-based thermoplastic elastomer, styrene-based thermoplastic elastomer, polyamide elastomer, and polyamide, and more preferably at least one selected from the group consisting of polyurethane and polyamide elastomer.

[0032] The distal end 3B of the outer member 3 is preferably located distal to the thickest part 7PT, which is the thickest part of the protrusion 7P. This makes it even more difficult for the tip 7 to detach from the second tubular member 2.

[0033] The distal end 3B of the outer member 3 is preferably located distal to the distal end 7PB of the protrusion 7P. This makes it even more difficult for the tip 7 to detach from the second tubular member 2.

[0034] The distal end 3B of the outer member 3 is preferably located more proximal than the distal end 2B of the second tubular member 2. This makes it easier to insert the tip 7 into the body.

[0035] The first tubular member 1 and the second tubular member 2 each preferably have one or more layers extending in the longitudinal direction X, and more preferably have multiple layers. The multiple layers preferably include an inner layer and an outer layer enclosing at least a portion of the inner layer. The multiple layers may further include an intermediate layer positioned between the inner layer and the outer layer. The number of intermediate layers is not limited to one, but may be two or more. It is preferable that each of the multiple layers contains a different material from the adjacent layers. The inner layer of the first tubular member 1 and the inner layer of the second tubular member 2 each preferably contains at least one resin selected from the group consisting of polyolefin resins and fluorine-based resins. This improves the slidability of the guidewire inserted into the lumen 1L and the lumen 2L. The polyolefin resin is preferably polyethylene, polypropylene, an ethylene-propylene copolymer, or a mixture thereof. The polyethylene is preferably high-density polyethylene with a specific gravity of 0.942 or higher. The fluorine-based resin is preferably polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, or a mixture thereof. The inner layer of the first cylindrical member 1 and the inner layer of the second cylindrical member 2 may each contain at least one selected from the group consisting of polyamide-based resin, polyester-based resin, polyurethane-based resin, polyolefin-based resin, fluorine-based resin, vinyl chloride-based resin, silicone-based resin, and natural rubber. The inner layer of the first cylindrical member 1 and the inner layer of the second cylindrical member 2 may contain different resins, but preferably contain the same resin, and more preferably are made of the same resin.

[0036] The outer layer of the first tubular member 1 and the outer layer of the second tubular member 2 each preferably contain a flexible resin. The inclusion of a flexible resin in the outer layer improves the flexibility of the catheter 91. The flexible resin preferably contains at least one selected from the group consisting of polyethylene, polyurethane, polyurethane-based thermoplastic elastomer, styrene-based thermoplastic elastomer, polyamide elastomer, and polyamide, and more preferably contains at least one selected from the group consisting of polyurethane and polyamide elastomer. The polyethylene is preferably low-density polyethylene with a specific gravity of 0.91 to 0.92.

[0037] The Shore D hardness of the material of the outer layer is preferably equal to or smaller than the Shore D hardness of the material of the inner layer, and preferably smaller, which allows the catheter 91 to bend more easily. The Shore D hardness may be measured, for example, using a durometer type D in accordance with ISO 7619.

[0038] The intermediate layer preferably comprises a different material than the inner or outer layer, but may comprise the same material as the inner or outer layer.

[0039] The inner layer, intermediate layer, and outer layer are preferably fixed to the adjacent layers. This prevents the layers from twisting or kinking. Fixation methods include, for example, welding and adhesive bonding. Although not shown, a reinforcing member may be disposed as an intermediate layer. Talc may also be disposed between the tip 7 and the second tubular member 2 and / or between the tip 7 and the outer member 3. This reduces the tackiness of the surface of the tip 7, making it easier to insert the second tubular member 2 into the tip 7 during manufacturing. This also makes it easier to cover the tip 7 with the outer member 3.

[0040] The first tubular member 1 preferably includes a reinforcing member, which can easily prevent the wire from breaking through the first tubular member 1. On the other hand, the second tubular member 2 preferably does not include a reinforcing member, which can easily improve the flexibility of the second tubular member 2.

[0041] The reinforcing member is preferably a braided body made of braided wires, a coiled body made of spirally wound wires, or a combination thereof. This can more easily prevent the guide wire from breaking through the first tubular member 1. Of these, a braided body is more preferable as the reinforcing member because it is more likely to improve rigidity. Examples of wires contained in the reinforcing member include metal wires and fibers. The metal wire preferably includes stainless steel, titanium, a nickel-titanium alloy, a cobalt-chromium alloy, a tungsten alloy, or an alloy thereof. Of these, stainless steel is more preferable. The metal wire may be a solid wire or a twisted wire. The fiber is preferably polyarylate fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, carbon fiber, or a blend thereof. The fiber may be monofilament or multifilament. The reinforcing member may include a radiopaque material to make it easier to confirm the position of the first tubular member 1 under X-ray fluoroscopy, etc. The radiopaque material is preferably at least one selected from the group consisting of lead, barium, iodine, tungsten, gold, platinum, iridium, platinum-iridium alloy, stainless steel, titanium, cobalt-chromium alloy, palladium, bismuth, and tantalum.

[0042] Although not shown, the distal end of the reinforcing member is preferably located proximal to the proximal end of the first opening 1E and distal to the proximal end 2A of the second tubular member 2. On the other hand, the proximal end of the reinforcing member is preferably located proximal to the proximal end 2A of the second tubular member 2, and more preferably located within the handle portion 8. This makes it easier to prevent the guidewire from puncturing the first tubular member 1.

[0043] It is preferable that the length in the longitudinal direction X from the distal end 2B of the second tubular member 2 to the proximal end 7A of the tip 7 be longer than the length in the longitudinal direction X from the distal end 2B of the second tubular member 2 to the distal end 7B of the tip 7. This increases the contact area between the second tubular member 2 and the tip 7, making it even more difficult for the tip 7 to come off.

[0044] 2, the distal end 1B of the first tubular member 1 is located more proximal than the distal end 2B of the second tubular member 2. This makes the catheter 91 more easily bendable in the portion distal to the distal end 1B of the first tubular member 1, making it easier to insert into a curved portion such as a blood vessel inside the body.

[0045] 1 and 3, the proximal end 1A of the first tubular member 1 is located proximal to the proximal end 2A of the second tubular member 2. This allows the portion of the catheter 91 proximal to the proximal end 2A of the second tubular member 2 to have, for example, a double-tube structure (coaxial structure), which is different from the structure in which the first tubular member 1 and the second tubular member 2 distal to the proximal end 2A of the second tubular member 2 overlap in the radial direction Y, and allows different functions to be achieved.

[0046] As shown in FIG. 2 , the outer member 3 preferably has a protruding portion 31 protruding in a direction away from the central axis 2C on the side distal to the distal end 1B of the first tubular member 1 and closer to the first tubular member 1 in the radial direction Y. This allows the tip of the wire inserted into the first tubular member 1 to be guided in a direction different from the tip of the wire inserted into the second tubular member 2, facilitating treatment of bifurcation lesions, etc. This also makes it less likely for the wires to become entangled. The protruding portion 31 is preferably adjacent to the distal end 1B of the first tubular member 1. This makes it easier to guide the wire emerging from the first opening 1E by the protruding portion 31. The outer member 3 at the protruding portion 31 is preferably thicker than the outer member 3 around the protruding portion 31.

[0047] As shown in FIG. 2 , when a cross section X is defined as a cross section in the longitudinal direction X including the central axis 1C of the first tubular member 1 and the central axis 2C of the second tubular member 2, the protruding portion 31 preferably has a first inclined portion inclined away from the central axis 2C as it approaches the distal side, and a second inclined portion inclined toward the central axis 2C as it approaches the distal side. The second inclined portion is preferably located distal to the first inclined portion. The first inclined portion facilitates guiding the wire exiting the first opening 1E. The second inclined portion facilitates insertion into the body. The outer surfaces of the first inclined portion and the second inclined portion in the cross section X are preferably linear or curved, more preferably linear. When the outer surface of the second inclined portion in the cross section X is linear, the shape of the second inclined portion is a so-called tapered shape.

[0048] 5, the outer member 3 does not necessarily have to have a protruding portion protruding in a direction away from the central axis 2C on the side distal to the distal end 1B of the first tubular member 1 and closer to the first tubular member 1 in the radial direction Y. In this case, the protruding portion 7P of the tip 7 can function as a protruding portion to guide the wire.

[0049] As shown in FIG. 6 , the first tubular member 1 and the second tubular member 2 are preferably fixed to each other in the radial direction Y. Specifically, the outer surfaces of the first tubular member 1 and the second tubular member 2 are preferably fixed to each other in the radial direction Y. This makes the second tubular member 2 less likely to twist or distort. Examples of fixing methods include welding and adhesive bonding. Also, as shown in FIG. 6 , in the cross section of the catheter 91 in the radial direction Y, the shapes of the first lumen 1L and the second lumen 2L are preferably circular, elliptical, arcuate, or a combination thereof, and more preferably circular or elliptical. This makes the catheter 91 more easily bendable. Within the catheter 91, the first lumen 1L and the second lumen 2L are preferably not in communication. In the cross section of the radial direction Y, the first lumen 1L may have a larger area than the second lumen 2L, a smaller area than the second lumen 2L, or the same area as the second lumen 2L.

[0050] 2, the first tubular member 1 preferably has a first opening 1E communicating with the lumen 1L. The first opening 1E can be used as an entrance or exit for a guide wire.

[0051] 2, the second tubular member 2 preferably has a second opening 2E communicating with the lumen 2L. The second opening 2E can be used as an entrance or exit for a guide wire.

[0052] As shown in FIG. 1 , a handle portion 8 is preferably disposed at the proximal end 1a of the first tubular member 1. Specifically, the proximal end 1a of the first tubular member 1 is preferably disposed within the handle portion 8. The practitioner can insert the catheter 91 into the body by grasping and pushing the handle portion 8. The outer shape of the handle portion 8 may be such that the practitioner can grasp it with their fingers. The handle portion 8 is preferably a resin molded product obtained by injection molding or the like. Examples of resins include polyolefin resins such as polyethylene and polypropylene, polycarbonate resins, and (meth)acrylic resins. Of these resins, transparent resins such as polycarbonate and polymethyl methacrylate are preferred. This makes it easier to see inside the handle portion 8 and facilitates wire insertion.

[0053] The proximal end 1A of the first tubular member 1 is preferably located within the handle portion 8. This can improve pushability.

[0054] The handle portion 8 preferably has an inner cavity that communicates with the inner cavity 1L of the first tubular member 1 and extends in the longitudinal direction X, and a guide wire can be inserted through this inner cavity.

[0055] As shown in FIGS. 1 and 3 , the catheter 91 preferably further includes an outer tubular member 4 extending in the longitudinal direction X. The outer tubular member 4 preferably has a lumen 4L extending in the longitudinal direction X, with a portion of the first tubular member 1 disposed in the lumen 4L. The outer tubular member 4 forms a double-tube structure (coaxial structure), which protects the first tubular member 1 and improves the transmission of pushing force. Specifically, the outer tubular member 4 preferably has a fixed portion fixed to the first tubular member 1 at its distal end and a non-fixed portion proximal to the fixed portion and not fixed to the first tubular member 1. The outer tubular member 4 also preferably has a fixed portion fixed to the handle portion 8 at its proximal end.

[0056] The outer cylindrical member 4 is preferably located proximal to the proximal end 2A of the second cylindrical member 2. This allows the outer diameter of the outer cylindrical member 4 to be reduced.

[0057] The outer tubular member 4 preferably contains the same resin as the outer member 3 or a harder resin, and more preferably is made of a harder resin. A harder resin can improve pushability. In addition, the distal end of the outer tubular member 4 and the proximal end of the outer member 3 are preferably fixed to each other.

[0058] 2, the first tubular member 1 may have a radiopaque marker 6A proximal to the proximal end of the first opening 1E and distal to a point 1 cm proximally from the proximal end of the first opening 1E, which makes it easier to grasp the position of the first opening 1E.

[0059] The second tubular member 2 may have an X-ray opaque marker 6B at a position distal to the proximal end 7A of the tip 7 and proximal to the distal end 7B of the tip 7. This makes it easier to grasp the position of the tip 7 when inserting the tip 7 into a curved portion inside the body, for example, and therefore makes insertion easier.

[0060] The radiopaque markers 6A and 6B are preferably ring-shaped. Each of the radiopaque markers 6A and 6B preferably contains a radiopaque material, and more preferably is made of a radiopaque material. The radiopaque material is preferably at least one selected from the group consisting of lead, barium, iodine, tungsten, gold, platinum, iridium, platinum-iridium alloy, stainless steel, titanium, cobalt-chromium alloy, palladium, bismuth, and tantalum.

[0061] Although not shown, the catheter 91 preferably further includes a linear member extending in the longitudinal direction X and at least a portion of which is disposed within the outer cylindrical member 4. This improves the transmission of pushing force. The linear member is preferably straight. The linear member may include one or more linear members. The proximal end of the linear member is preferably located within the handle portion 8. The distal end of the linear member is preferably located within the outer cylindrical member 4 or the outer member 3. The linear member is preferably a solid member without an internal lumen. The linear member preferably contains a metal, and more preferably is made of a metal. The metal is preferably stainless steel, nickel titanium, cobalt chromium, or an alloy thereof. The linear member preferably has a shaped portion extending in the longitudinal direction X and having the same radial cross-sectional shape. The linear member more preferably has a tapered portion located distal to the shaped portion and tapering toward the distal side.

[0062] The catheter 91 can be preferably used for treatment of narrowing or dilating blocked areas of passages such as blood vessels in the body, and can be preferably used for performing coronary intervention (PCI) for lesions at the bifurcation of coronary arteries.

[0063] A catheter according to the second embodiment will be described below with reference to Figures 7 to 10. Figure 7 is a side view of the catheter according to the second embodiment. Figure 8 is a longitudinal cross-sectional view of region R1 in Figure 7. Figure 9 is a longitudinal cross-sectional view of region R2 in Figure 7. Figure 10 is a cross-sectional view of the catheter taken along line A-A in Figure 7. A detailed description of portions of the catheter according to the second embodiment that overlap with those of the catheter according to the first embodiment will be omitted.

[0064] The catheter according to the second embodiment is a catheter 92 having a first cylindrical member 1 extending in the longitudinal direction X, a second cylindrical member 2 extending in the longitudinal direction X and adjacent to the first cylindrical member 1 in the radial direction Y, and an outer member 3 extending in the longitudinal direction X and having a portion that encloses at least a portion of the first cylindrical member 1 and at least a portion of the second cylindrical member 2. For details of each part, please refer to the description of the catheter 91.

[0065] As shown in FIG. 7 , in the catheter 92, the outer member 3 preferably has a columnar body 5 extending in the longitudinal direction X and containing a resin, and at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2 are preferably disposed within the columnar body 5. That is, at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2 are preferably sealed by the columnar body 5 extending in the longitudinal direction X and containing a resin. This makes it easier to maintain the shapes of the lumens 1L and 2L extending in the longitudinal direction X even when the catheter 92 is bent. The columnar body 5 is preferably disposed at least between the proximal end 2A of the second tubular member 2 and the distal end 3B of the outer member 3. Note that the resin of the columnar body 5 may be present between the first tubular member 1 and the second tubular member 2.

[0066] The shape of the cylinder 5 is preferably a circular cylinder, an elliptical cylinder, or a rounded polygonal cylinder, and more preferably a circular cylinder or an elliptical cylinder, which makes it easier to insert the catheter 92 into the body.

[0067] The cylinder 5 may be formed by covering the first tubular member 1 and the second tubular member 2 stacked in the radial direction Y with a resin tube and heating and welding them together, or the cylinder 5 may be formed by injection molding the first tubular member 1 and the second tubular member 2 stacked in the radial direction Y.

[0068] It is preferable that at least a portion of the inner surface of the outer member 3 is fixed to the outer surfaces of the first cylindrical member 1 and the second cylindrical member 2. This makes it difficult for the outer member 3 to twist or distort. Examples of the fixing method include welding, adhesion, etc.

[0069] This application claims the benefit of priority based on Japanese Patent Application No. 2023-125556, filed on August 1, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-125556, filed on August 1, 2023, are incorporated herein by reference.

[0070] 1 First cylindrical member 1a Proximal end 1A Proximal end 1B Distal end 1C Central axis 1E First opening 1L Lumen 2 Second cylindrical member 2A Proximal end 2B Distal end 2b Distal end 2C Central axis 2E Second opening 2L Lumen 3 Outer member 3B Distal end 3L Lumen 4 Outer cylindrical member 4L Lumen 5 Pillars 6A, 6B X-ray opaque marker 7 Chip 7a Proximal end 7A Proximal end 7B Distal end 7C Central axis 7L Lumen 7P Projection 7PB Distal end 7PT Thickest part 7U1 First thin part 7T1 First thick part 8 Handle part 31 Raised portion 71 First region 72 Second region 91, 92 Catheter X: Longitudinal direction Y: Radial direction

Claims

1. A catheter having a first tubular member extending in a longitudinal direction; a second tubular member extending in the longitudinal direction and radially adjacent to the first tubular member; an outer member extending in the longitudinal direction and having a portion containing at least a portion of the first tubular member and at least a portion of the second tubular member; and a tip extending in the longitudinal direction disposed at a distal end of the second tubular member, wherein the distal end of the first tubular member is located proximal to the distal end of the second tubular member, the proximal end of the first tubular member is located proximal to the proximal end of the second tubular member, the tip has a protruding portion protruding in a direction away from a central axis of the tip, and the outer member covers at least a portion of the protruding portion.

2. The catheter according to claim 1, wherein the distal end of the outer member is located distal to a thickest portion that is the thickest part of the protrusion.

3. The catheter of claim 1, wherein the distal end of the outer member is located distal to the distal end of the projection.

4. The catheter according to claim 1, wherein the distal end of the outer member is located proximal to the distal end of the second tubular member.

5. The catheter of claim 1, wherein the protrusion is located at a proximal end of the tip.

6. A catheter as described in claim 1, wherein the tip has, in the radial direction, a first region closer to the first tubular member and a second region farther from the first tubular member, and the first region has the protrusion.

7. The catheter of claim 1, wherein said tip is fixed to said second tubular member and not fixed to said outer member.

8. The catheter according to claim 7, wherein said tip has metal powder at least on its outer surface that is covered by said outer member.

9. The catheter of claim 1, wherein said tip has a lumen extending in said longitudinal direction, and wherein at least said distal end of said second tubular member is disposed within said lumen.

10. A catheter as described in claim 9, wherein the diameter of the inner lumen of the tip distal to the distal end of the second tubular member is greater than or the same length as the inner diameter of the second tubular member at the distal end of the second tubular member.

11. The catheter according to claim 1, wherein the tip has a first thin-walled portion located distal to the protruding portion and thinner than the protruding portion, and a first thick-walled portion located distal to the first thin-walled portion and thicker than the first thin-walled portion.

12. The catheter of claim 1, wherein the outer member is tubular and has an inner lumen extending in the longitudinal direction, and at least a portion of the first tubular member and at least a portion of the second tubular member are disposed in the lumen.

13. The catheter according to claim 1, wherein the outer member has a columnar body extending in the longitudinal direction and containing resin, and at least a portion of the first tubular member and at least a portion of the second tubular member are disposed within the columnar body.

14. The catheter according to claim 1, wherein the first tubular member and the second tubular member are fixed to each other in the radial direction.

15. The catheter of claim 1, wherein the first tubular member has a handle portion disposed at a proximal end thereof.

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