Catheter

Abstract

Provided is a catheter which is easy to be inserted into a curved part in a body. The catheter has: a first cylindrical member extending in the longitudinal direction; a second cylindrical member adjacent to the first cylindrical member in the radial direction; and an outer member having a portion including at least a part of the first cylindrical member and at least a part of the second cylindrical member. The distal end of the first cylindrical member is positioned closer to the proximal side than the distal end of the second cylindrical member, and 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 second cylindrical member has a first region on the side closer to the first cylindrical member in the radial direction, and a second region on the side farther from the first cylindrical member. In a cross section in the longitudinal direction including the central axis of the first cylindrical member and the central axis of the second cylindrical member, the second region of the second cylindrical member has a thin-walled section positioned closer to the distal side than the distal end of the first cylindrical member. On a virtual straight line extending in the radial direction of the cross section, and passing through the thin-walled section and the first region, the thin-walled section is thinner than the first region.

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 inventors' investigations revealed that conventional catheters may bend at the distal end of the inner layer of the catheter and in the vicinity thereof when the catheter is inserted into a curved portion such as a blood vessel. For example, when inserting a catheter into a target site using a guidewire, if a portion of the catheter is bent, the inner surface of the catheter comes into contact with the guidewire, making it difficult to insert the catheter. The present invention was made in light of the above circumstances, and its object is to provide a catheter that is easy to insert into a curved portion inside the body.

[0005] The catheter according to the embodiment of the present invention that can solve the above problems is 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 adjacent to the first tubular member in a radial direction, and an outer member extending in the longitudinal direction and having a portion that contains at least a part of the first tubular member and at least a part 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 second tubular member has, in the radial direction, a first region closer to the first tubular member and a second region farther from the first tubular member, In the longitudinal cross section including the central axis of the first tubular member and the central axis of the second tubular member, the second region of the second tubular member has a thin-walled portion distal to the distal end of the first tubular member, and the thin-walled portion is thinner than the first region on an imaginary line extending radially in the cross section and passing through the thin-walled portion and the first region.

[0006] The second tubular member has a thin-walled portion that faces the first region in the radial direction and is relatively thin, so the catheter is easily bent in the direction from the first region toward the thin-walled portion, making it difficult to bend in that direction. As a result, the catheter is difficult to bend even when inserted into a curved portion inside the body, making it easy to insert into a curved portion inside the body.

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

[17] . [2] The catheter according to [1], wherein, in the cross section, the distal end of the second region of the second tubular member becomes thinner toward the distal end of the second tubular member, and the distal end of the second region includes the thin-walled portion. [3] The catheter according to [2], wherein, in the cross section, the outer surface of the distal end of the second region is inclined so as to approach the central axis of the second tubular member toward the distal end of the second tubular member. [4] The catheter according to any one of [1] to [3], wherein, in the cross section, the distal end of the first region is inclined so as to approach the central axis of the second tubular member toward the distal end of the second tubular member. [5] The catheter according to [4], wherein, in the cross section, the outer surface of the distal end of the first region is inclined so as to approach the central axis of the second tubular member toward the distal end of the second tubular member. [6] The catheter according to [5], wherein, in the cross section, the inclination angle of the outer surface of the distal end portion of the second region with respect to the central axis of the second tubular member is smaller than the inclination angle of the outer surface of the distal end portion of the first region with respect to the central axis of the second tubular member. [7] The catheter according to any of [4] to [6], wherein, in the cross section, the length of the distal end portion of the second region in the longitudinal direction is longer than the length of the distal end portion of the first region in the longitudinal direction. [8] The catheter according to any of [2] to [7], wherein the length of the distal end portion of the second region in the longitudinal direction is longer than the maximum thickness of the second tubular member. [9] A catheter described in any of [1] to [8], wherein the outer member has a main body portion containing a portion of the first tubular member and a portion of the second tubular member, a first tip portion located distal to the main body portion and containing the distal end of the first tubular member, and a second tip portion located distal to the main body portion and containing the distal end of the second tubular member, and the second tip portion contains a material different from the material contained in the first tip portion and the main body portion.

[10] The catheter according to any one of [1] to [9], 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.

[11] The catheter according to any one of [1] to [9], wherein the outer member is cylindrical 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 within the inner lumen.

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

[11] , wherein the distal end of the outer member is located distal to the distal end of the second tubular member.

[13] The catheter according to

[12] , wherein the length in the longitudinal direction from the distal end of the outer member to the distal end of the second tubular member is longer than or the same as the length in the longitudinal direction of the distal end portion of the second region of the second tubular member.

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

[13] , further comprising a tip extending in the longitudinal direction, the tip having a lumen extending in the longitudinal direction, and at least the distal end portion of the second region of the second tubular member being disposed within the lumen.

[15] The catheter according to any one of [2] to

[14] , wherein, in the cross section, the inner surface of the distal end portion of the second region is inclined so as to move away from the central axis of the second tubular member toward the distal end of the second tubular member.

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

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

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

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

[0008] According to the present invention, with the above-mentioned configuration, it is possible to provide a catheter that can be easily inserted into curved parts inside the body.

[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 of FIG. 1. FIG. 3 is a longitudinal cross-sectional view of region R2 of FIG. 1. FIG. 4 is a schematic diagram showing an example of inserting the catheter of FIG. 1 into a curved portion inside a body. FIG. 5 is a schematic diagram showing another example of inserting the catheter of FIG. 1 into a curved portion inside a body. FIG. 6 is a schematic diagram showing an example of inserting a catheter in which the second tubular member does not have a thin-walled portion into a curved portion inside a body. FIG. 7 is a cross-sectional view of the catheter of FIG. 1 taken along line A-A. FIG. 8 is a longitudinal cross-sectional view of a modified example of region R1 of FIG. 1. FIG. 9 is a side view of a catheter according to a second embodiment. FIG. 10 is a longitudinal cross-sectional view of region R1 of FIG. 9. FIG. 11 is a longitudinal cross-sectional view of region R2 of FIG. 9. FIG. 12 is a cross-sectional view of the catheter of FIG. 9 taken along line A-A. FIG. 13 is a longitudinal cross-sectional view of a distal portion of a catheter according to a third embodiment.

[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 according to the embodiment includes a first tubular member extending in a longitudinal direction, a second tubular member extending in a longitudinal direction and radially adjacent to the first tubular member, and an outer member extending in a 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, wherein the distal end of the first tubular member is located proximal to the distal end of the second tubular member, and the proximal end of the first tubular member is located proximal to the proximal end of the second tubular member. The second tubular member is located proximal to the first tubular member, and the second tubular member 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 in a longitudinal cross section including the central axis of the first tubular member and the central axis of the second tubular member, the second region of the second tubular member has a thin-walled portion distal to the distal end of the first tubular member, and the thin-walled portion is thinner than the first region on an imaginary straight line extending radially in the cross section and passing through the thin-walled portion and the first region.

[0012] As described above, the second tubular member has a thin-walled portion that faces the first region in the radial direction and is relatively thin, so the catheter is easily bent in the direction from the first region toward the thin-walled portion, making it less likely to bend in that direction. As a result, the catheter is less likely to bend even when inserted into a curved portion inside the body, making it easier to insert into a curved portion inside the body.

[0013] A catheter according to a first embodiment will be described below with reference to FIGS. 1 to 8. FIG. 1 is a side view of the catheter according to the 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 schematic diagram showing an example of inserting the catheter of FIG. 1 into a curved portion inside a body. FIG. 5 is a schematic diagram showing another example of inserting the catheter of FIG. 1 into a curved portion inside a body. FIG. 6 is a schematic diagram showing an example of inserting a catheter in which the second tubular member does not have a thin-walled portion into a curved portion inside a body. FIG. 7 is a cross-sectional view of the catheter of FIG. 1 taken along line A-A. FIG. 8 is a longitudinal cross-sectional view of a modified example of region R1 in FIG. 1.

[0014] As shown in FIGS. 1 , 2 , and 3 , the catheter according to the first embodiment is a catheter 91 having 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 first lumen 1L extending in the longitudinal direction X. The second tubular member 2 preferably has a second lumen 2L extending in the longitudinal direction X. By inserting, for example, a guidewire into each of the first lumen 1L and the second lumen 2L, the catheter 91 can be guided in multiple directions, thereby facilitating insertion of the catheter 91 into various branching portions of coronary arteries, 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 a probing wire into the lumen 1L. The distal end of the probing wire may be bent.

[0015] 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 first lumen 1L and the second 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.

[0016] 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. When the outer layers contain a flexible resin, the catheter 91 becomes more easily bendable. 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.

[0017] 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 more preferably smaller, which makes the catheter 91 more flexible. The Shore D hardness may be measured, for example, using a durometer type D in accordance with ISO 7619.

[0018] 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.

[0019] The inner layer, intermediate layer, and outer layer are preferably fixed to the adjacent layers, which makes each layer less likely to twist or distort. Fixing methods include welding and adhesion. Although not shown, a reinforcing member may be disposed as the intermediate layer.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] As shown in FIG. 7 , the outer surfaces of the first tubular member 1 and the second tubular member 2 may not be in contact with each other, or may be in contact and fixed to each other. Examples of fixing methods include welding and adhesive bonding. When the outer surfaces of the first tubular member 1 and the second tubular member 2 are not in contact with each other, they are preferably fixed to each other via the resin of the outer member 3. Also, as shown in FIG. 7 , in the cross section of the catheter 91 taken along 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 allows the catheter 91 to bend easily. Within the catheter 91, the first lumen 1L and the second lumen 2L are preferably not in communication with each other. 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.

[0024] 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 it easier for the catheter 91 to bend in the portion distal to the distal end 1B of the first tubular member 1.

[0025] 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.

[0026] 2, the second cylindrical member 2 has a first region 21 closer to the first cylindrical member 1 in the radial direction Y and a second region 22 farther from the first cylindrical member 1. The first region 21 and the second region 22 each preferably have a semi-cylindrical portion extending in the longitudinal direction X. These semi-cylindrical portions are preferably continuous and seamless in the circumferential direction.

[0027] As shown in FIG. 2 , in 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 (hereinafter referred to as the "cross section X"), the second region 22 of the second tubular member 2 has a thin-walled portion 22T distal to the distal end 1B of the first tubular member 1. On an imaginary line V extending in the radial direction Y of the cross section X and passing through the thin-walled portion 22T and the first region 21, the thin-walled portion 22T is thinner than the first region 21. In other words, at the same position in the longitudinal direction X of the cross section X, the thin-walled portion 22T is thinner than the first region 21. Such thin-walled portion 22T makes the catheter 91 more likely to bend in the direction from the first region 21 toward the thin-walled portion 22T, making it less likely to bend in that direction.

[0028] In detail, for example, when the catheter 91 is inserted with the second tubular member 2 side toward the inside 99I of the curved portion 99 inside the body as shown in Fig. 4 , the radius of curvature of the catheter 91 when curved is smaller by the length of the radial direction Y of the first tubular member 1 than when the catheter 91 is inserted with the first tubular member 1 side toward the inside 99I of the curved portion 99 inside the body as shown in Fig. 5 . Here, as shown in Fig. 6 , when a catheter in which the second tubular member 2 does not have a thin-walled portion is curved so as to have a smaller radius of curvature, the catheter is likely to bend due to the difference in rigidity between the distal end 2B of the second tubular member 2 and its vicinity. On the other hand, in the catheter 91, the second tubular member 2 has the first region 21 and the relatively thin-walled portion 22T arranged opposite each other. This makes the catheter more likely to bend in the direction from the first region 21 toward the thin-walled portion 22T, and therefore less likely to bend in that direction as shown in Fig. 4 . As a result, for example, when the guide wire 9 is inserted into the second lumen 2L of the second tubular member 2 and the catheter 91 is inserted into a curved portion 99 inside the body along the guide wire 9, the catheter 91 is less likely to bend even in a direction that results in a small radius of curvature, allowing for smooth insertion of the catheter 91. An example of the curved portion 99 inside the body is an artery such as a coronary artery.

[0029] 2, in cross section X, the distal end portion 22b of the second region 22 of the second tubular member 2 becomes thinner toward the distal end 2B of the second tubular member 2, and the distal end portion 22b of the second region 22 preferably includes a thin-walled portion 22T. Since the distal end portion 22b of the second region 22 becomes continuously thinner toward the distal side in this manner, the catheter 91 becomes more likely to bend in the direction from the first region 21 toward the thin-walled portion 22T. It is more preferable that the distal end portion 22b of the second region 22 be made of the thin-walled portion 22T.

[0030] In the cross section X, the outer surface 22S of the distal end 22b of the second region 22 is preferably inclined so as to approach the central axis 2C of the second cylindrical member 2 as it approaches the distal end 2B of the second cylindrical member 2. This makes it difficult for the catheter 91 to bend when it curves in the direction from the first region 21 toward the thin-walled portion 22T. The shape of the outer surface 22S in the cross section X is preferably linear or curved, and more preferably linear. When the outer surface 22S is linear, the distal end 22b has a so-called tapered shape.

[0031] In the cross section X, it is preferable that the distal end 21b of the first region 21 becomes thinner toward the distal end 2B of the second tubular member 2. By continuously thinning the distal end 21b of the first region 21 toward the distal side in this manner, the catheter 91 becomes easier to bend in the direction from the thin-walled portion 22T toward the first region 21, as shown in Fig. 5. Note that when the first tubular member 1 side is directed toward the inside 99I of a bending portion 99 inside the body as shown in Fig. 5, the radius of curvature of the catheter 91 when bent increases by the length of the first tubular member 1 in the radial direction Y, and therefore the distal end 21b of the first region 21 does not need to become continuously thinner toward the distal side.

[0032] 2, in cross section X, the outer surface 21S of the distal end 21b of the first region 21 is preferably inclined so as to approach the central axis 2C of the second tubular member 2 toward the distal end 2B of the second tubular member 2. This makes it difficult for the catheter 91 to bend when bending in the direction from the thin-walled portion 22T toward the first region 21.

[0033] In the cross section X, the inclination angle of the outer surface 22S of the distal end 22b of the second region 22 relative to the central axis 2C of the second tubular member 2 is preferably smaller than the inclination angle of the outer surface 21S of the distal end 21b of the first region 21 relative to the central axis 2C of the second tubular member 2. This makes it easier for the catheter 91 to bend in the direction from the first region 21 toward the thin-walled portion 22T.

[0034] In cross section X, the angle between outer surface 21S and central axis 2C, i.e., the inclination angle, is preferably 40 degrees or more and 80 degrees or less, more preferably 50 degrees or more and 70 degrees or less. In cross section X, the angle between outer surface 22S and central axis 2C, i.e., the inclination angle, is preferably 0.4 degrees or more and 45 degrees or less, more preferably 1 degree or more and 35 degrees or less.

[0035] The outer surface 21S and the outer surface 22S can be formed by, for example, cutting obliquely with a cutter a portion of the distal end of the tube formed by the second cylindrical member 2. Alternatively, the outer surface 21S and the outer surface 22S may be formed using a grinder.

[0036] In the cross section X, the length in the longitudinal direction X of the distal end portion 22b of the second region 22 is preferably longer than the length in the longitudinal direction X of the distal end portion 21b of the first region 21. This makes it easier for the catheter 91 to bend in the direction from the first region 21 toward the thin-walled portion 22T. Specifically, the length in the longitudinal direction X of the distal end portion 22b is preferably more than 1 time and not more than 275 times, and more preferably 5 times or more and not more than 185 times, the length in the longitudinal direction X of the distal end portion 21b. Furthermore, the length in the longitudinal direction X of the distal end portion 22b of the second region 22 is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.5 mm or more and 2.0 mm or less.

[0037] The length of the distal end 22b of the second region 22 in the longitudinal direction X is preferably greater than the maximum thickness of the second tubular member 2. This makes it easier for the catheter 91 to bend in the direction from the first region 21 toward the thin-walled portion 22T.

[0038] It is more preferable that the length in the longitudinal direction X of the distal end portion 22b of the second region 22 be greater than the maximum outer diameter of the second tubular member 2. This makes it easier for the catheter 91 to bend in the direction from the first region 21 toward the thin-walled portion 22T. The maximum outer diameter of the second tubular member 2 is preferably 0.2 mm or more and 1.2 mm or less, and more preferably 0.4 mm or more and 0.8 mm or less.

[0039] 2, 3, and 7, the catheter 91 has 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 make it easier to prevent the guide wire 9 from breaking through from inside the catheter 91.

[0040] 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.

[0041] As shown in FIG. 7 , the outer member 3 preferably has a columnar body 5 extending in the longitudinal direction X and containing a resin, with at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2 being 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 first lumen 1L and the second lumen 2L extending in the longitudinal direction X even when the catheter 91 is bent. The columnar body 5 is preferably disposed at least between the proximal end 2A and the distal end 2B of the second tubular member 2. Note that the resin of the columnar body 5 may be present between the first tubular member 1 and the second tubular member 2.

[0042] 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 91 into the body.

[0043] 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.

[0044] 2, the distal end 3B of the outer member 3 is preferably located distal to the distal end 2B of the second tubular member 2. By arranging the outer member 3 made of a flexible material in this manner, the flexibility of the portion of the catheter 91 distal to the distal end 2B of the second tubular member 2 can be improved.

[0045] 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.

[0046] The length in the longitudinal direction X from the distal end 3B of the outer member 3 to the distal end 2B of the second tubular member 2 is preferably longer than or the same as the length in the longitudinal direction X of the distal end portion 22b of the second region 22 of the second tubular member 2, and more preferably longer than the length of the distal end portion 22b in the longitudinal direction X. This improves the flexibility of the catheter 91 in the vicinity of its distal end.

[0047] As shown in Figure 8, the outer member 3 preferably includes a main body portion 33 containing a portion of the first tubular member 1 and a portion of the second tubular member 2, a first tip portion 31 located distal to the main body portion 33 and containing the distal end portion 1b of the first tubular member 1, and a second tip portion 32 located distal to the main body portion 33 and containing the distal end portion 2b of the second tubular member 2. Furthermore, the second tip portion 32 preferably includes a material different from the materials included in the first tip portion 31 and the main body portion 33. For example, if the second tip portion 32 includes a material more flexible than the materials included in the first tip portion 31 and the main body portion 33, damage to biological tissue by the tip portion of the catheter 91 can be more easily avoided. Note that although Figure 8 illustrates a boundary between the main body portion 33 and the first tip portion 31, the boundary may be eliminated by welding.

[0048] 2, the first tubular member 1 preferably has a first opening 1E communicating with the first lumen 1L. The first opening 1E can be used as an entrance or exit for the guide wire 9.

[0049] 2, the second tubular member 2 preferably has a second opening 2E communicating with the second lumen 2L. The second opening 2E can be used as an entrance or exit for the guide wire 9.

[0050] The outer member 3 preferably has a protruding portion 34 protruding in a direction away from the central axis 2C on the side closer to the first tubular member 1 in the radial direction Y than the distal end 1B of the first tubular member 1. This allows the tip of the wire inserted into the first tubular member 1 to be guided in a different direction from the tip of the wire inserted into the second tubular member 2, making it easier to treat bifurcation lesions, etc. This also makes it less likely for the wires to become tangled. The protruding portion 34 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 34.

[0051] On the other hand, the outer member 3 may not 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 cylindrical member 1 and closer to the first cylindrical member 1 in the radial direction Y. This reduces the outer diameter of the catheter 91 by the amount of the protruding portion, making the catheter 91 easier to bend.

[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 first inner cavity 1L of the first tubular member 1 and extends in the longitudinal direction X, and a guide wire 9 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 fourth lumen 4L extending in the longitudinal direction X, and a portion of the first tubular member 1 is preferably disposed in the fourth lumen 4L. The outer tubular member 4 forms a double-tube structure (coaxial structure), which protects the first tubular member 1 and improves pushing force transmission. 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 distal end 1B of the first tubular member 1 and proximal to the thin-walled portion 22T. This makes it easier to grasp the position of the curved portion 99 of the catheter 91 when inserting the catheter 91 into the curved portion 99 inside the body, thereby facilitating insertion.

[0060] The radiopaque marker is preferably ring-shaped. The radiopaque marker preferably contains a radiopaque material, and more preferably consists 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 9 to 12. Figure 9 is a side view of the catheter according to the second embodiment. Figure 10 is a longitudinal cross-sectional view of region R1 in Figure 9. Figure 11 is a longitudinal cross-sectional view of region R2 in Figure 9. Figure 12 is a cross-sectional view of the catheter shown in Figure 9 taken along line A-A. 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 Figures 9 to 12, in a catheter 92, the outer member 3 is cylindrical and has a lumen 3L extending in the longitudinal direction X, with at least a portion of the first tubular member 1 and at least a portion of the second tubular member 2 preferably 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 9 from inside the catheter 92 and, as a result, making it easier to prevent the guidewire 9 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 susceptible to kinking or twisting.

[0066] The first cylindrical member 1 and the second cylindrical member 2 are preferably fixed to each other in the radial direction Y. Specifically, the outer surfaces of the first cylindrical member 1 and the second cylindrical member 2 are preferably fixed to each other in the radial direction Y. This makes the second cylindrical member 2 less likely to twist or distort. Examples of the fixing method include welding and adhesive bonding.

[0067] A catheter according to the third embodiment will be described below with reference to Fig. 13 and other figures. Fig. 13 is a longitudinal cross-sectional view of the distal portion of the catheter according to the third embodiment. Detailed descriptions of portions of the catheter according to the third embodiment that overlap with the catheter according to the first embodiment and the catheter according to the second embodiment will be omitted.

[0068] The catheter according to the third embodiment is a catheter 93 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 contains 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.

[0069] The catheter 93 further has a tip 7 extending in the longitudinal direction X, and the tip 7 has an inner lumen 7L extending in the longitudinal direction X, and it is preferable that at least the distal end portion 22b of the second region 22 of the second tubular member 2 is disposed within the inner lumen 7L. This makes it easier for the tip 7 and the second tubular member 2 to bend in the direction from the first region 21 toward the thin-walled portion 22T.

[0070] 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. This makes it easier for the tip 7 and the second cylindrical member 2 to bend integrally in the direction from the first region 21 toward the thin-walled portion 22T. Examples of the manner of fixing include welding and adhesive bonding.

[0071] In the cross section X, the inner surface 22I of the distal end portion 22b of the second region 22 is preferably inclined so as to move away from the central axis 2C of the second cylindrical member 2 toward the distal end 2B of the second cylindrical member 2. Since the inner surface 22I is inclined so as to move away from the central axis 2C from the proximal side toward the distal side, the catheter 93 becomes more likely to bend in the direction from the first region 21 toward the thin-walled portion 22T.

[0072] 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 the diameter of the second lumen 2L at the proximal end of the thin-walled portion 22T, which makes the tip 7 more easily bendable.

[0073] The tip 7 preferably contains a flexible resin. 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.

[0074] This application claims the benefit of priority based on Japanese Patent Application No. 2023-125554, filed on August 1, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-125554, filed on August 1, 2023, are incorporated herein by reference.

[0075] 1 First cylindrical member 1a Proximal end 1b Distal end 1A Proximal end 1B Distal end 1C Central axis 1E First opening 1L First lumen 2 Second cylindrical member 2b Distal end 2A Proximal end 2B Distal end 2C Central axis 2E Second opening 2L Second lumen 3 Outer member 3B Distal end 3L Lumen 4 Outer cylindrical member 4L Fourth lumen 5 Pillars 6A, 6B X-ray opaque marker 7 Tip 7L Lumen 8 Handle portion 9 Guide wire 21 First region 21b Distal end 21S Outer surface 22 Second region 22b Distal end 22I Inner surface 22S Outer surface 22T Thin wall portion 31 First tip portion 32 Second tip portion 33 Main body 34 Protuberances 91, 92, 93 Catheter 99 Curved portion inside the body 99I Inside of the curved portion V Imaginary straight line 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 adjacent to the first tubular member in a radial direction, and 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, wherein a distal end of the first tubular member is located proximal to a distal end of the second tubular member, a proximal end of the first tubular member is located proximal to a proximal end of the second tubular member, and the second tubular member has, in the radial direction, a first region closer to the first tubular member and a second region farther from the first tubular member, A catheter in which, in the longitudinal cross section including the central axis of the first tubular member and the central axis of the second tubular member, the second region of the second tubular member has a thin-walled portion distal to the distal end of the first tubular member, and the thin-walled portion is thinner than the first region on a virtual straight line extending radially in the cross section and passing through the thin-walled portion and the first region.

2. A catheter as described in claim 1, wherein in the cross section, the distal end of the second region of the second tubular member becomes thinner toward the distal end of the second tubular member, and the distal end of the second region includes the thin-walled portion.

3. A catheter as described in claim 2, wherein in the cross section, the outer surface of the distal end of the second region is inclined so as to approach the central axis of the second tubular member toward the distal end of the second tubular member.

4. The catheter according to claim 3, wherein in said cross section, the distal end of said first region becomes thinner toward said distal end of said second tubular member.

5. A catheter as described in claim 4, wherein in the cross section, the outer surface of the distal end of the first region is inclined so as to approach the central axis of the second tubular member toward the distal end of the second tubular member.

6. A catheter as described in claim 5, wherein, in the cross section, the inclination angle of the outer surface of the distal end portion of the second region relative to the central axis of the second tubular member is smaller than the inclination angle of the outer surface of the distal end portion of the first region relative to the central axis of the second tubular member.

7. The catheter according to claim 4, wherein, in the cross section, the length of the distal end of the second region in the longitudinal direction is longer than the length of the distal end of the first region in the longitudinal direction.

8. The catheter according to claim 2, wherein the length of the distal end of the second region in the longitudinal direction is greater than the maximum thickness of the second tubular member.

9. A catheter as described in claim 2, wherein the outer member has a main body portion containing a portion of the first tubular member and a portion of the second tubular member, a first tip portion located distal to the main body portion and containing the distal end of the first tubular member, and a second tip portion located distal to the main body portion and containing the distal end of the second tubular member, and the second tip portion contains a material different from the material contained in the first tip portion and the main body portion.

10. The catheter according to claim 2, 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.

11. The catheter of claim 2, wherein the outer member is tubular and has an inner lumen extending in the longitudinal direction, and wherein at least a portion of the first tubular member and at least a portion of the second tubular member are disposed in the lumen.

12. The catheter of claim 2, wherein a distal end of the outer member is located distal to the distal end of the second tubular member.

13. The catheter of claim 12, wherein the length in the longitudinal direction from the distal end of the outer member to the distal end of the second tubular member is longer than or the same as the length in the longitudinal direction of the distal end of the second region of the second tubular member.

14. The catheter of claim 2, further comprising a tip extending in said longitudinal direction, said tip having an inner lumen extending in said longitudinal direction, and wherein at least said distal end of said second region of said second tubular member is disposed within said lumen.

15. A catheter as described in claim 14, wherein, in the cross section, the inner surface of the distal end of the second region is inclined away from the central axis of the second tubular member toward the distal end of the second tubular member.

16. 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.

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

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