Catheter

Abstract

To provide a catheter which is hardly twisted even when inserted into a meandering part in the body, and in which a wire hardly breaks the catheter.SOLUTION: A catheter includes: a first cylindrical member extending in a longitudinal direction; a second cylindrical member extending in a longitudinal direction and adjacent to the first cylindrical member in a radial direction; and a first outside cylindrical member extending in a longitudinal direction and having a part that includes at least part of the first cylindrical member and at least part of the second cylindrical member. A distal end of the first cylindrical member is positioned more on a proximal side than a distal end of the second cylindrical member, and a proximal end of the first cylindrical member is positioned more on a proximal side than a proximal end of the second cylindrical member. The second cylindrical member includes a second stationary part fixed to the first outside cylindrical member. In at least one cross section of cross sections in the radial direction including the second stationary part, the first cylindrical member does not include a stationary part fixed to the first outside cylindrical member.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a catheter. [Background technology]

[0002] Catheters that can be inserted into blood vessels and the like to examine and treat lesions in the human body are used. For example, Patent Document 1 discloses an example of such a catheter, which includes a first tubular member extending in the longitudinal direction, having a distal end and a proximal end, and into which a wire is inserted, and a second tubular member having a distal end and a proximal end and adjacent to the first tubular member in the radial direction, the distal end of the first tubular member being located proximal to the distal end of the second tubular member, the proximal end of the first tubular member being located proximal to the proximal end of the second tubular member, the first tubular member having a reinforcing part having an inner layer containing at least one selected from the group consisting of polytetrafluoroethylene and tetrafluoroethylene-perfluoroalkylvinylether copolymer and a reinforcing member, and the first tubular member having a resin extension part not containing the polytetrafluoroethylene, the tetrafluoroethylene-perfluoroalkylvinylether copolymer, and the reinforcing member, distal to the distal end of the reinforcing part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 255737 Summary of the Invention [Problem to be solved by the invention]

[0004] When a conventional catheter such as that described in Patent Document 1 is inserted into a blood vessel such as a coronary artery that has a continuous three-dimensional meandering, the catheter may twist in the two-core parallel portion, which is a portion where the first tubular member and the second tubular member are adjacent in the radial direction. The inventors have found that twisting can be reduced by fixing the first tubular member and the second tubular member to each other in the two-core parallel portion and further fixing the first tubular member and the second tubular member to an outer tubular member that contains them. However, the inventors have found that when a catheter to which each tubular member is fixed as described above is inserted into a meandering portion in the body and a wire is inserted into the catheter after the insertion into the meandering portion, the wire may break through the first tubular member, which has a long longitudinal length. The present invention has been made in view of the above circumstances, and its purpose is to provide a catheter that is difficult to twist even when inserted into a meandering portion in the body and that is difficult for the wire to break through. [Means for solving the problem]

[0005] A catheter according to an embodiment of the present invention that can solve the above problems is as follows. [1] A first tubular member extending in a longitudinal direction; a second cylindrical member extending in the longitudinal direction and adjacent to the first cylindrical member in a radial direction; a first outer tubular 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, 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; the second tubular member has a second fixing portion fixed to the first outer tubular member, A catheter in which, in at least one of the radial cross sections including the second fixing portion, the first tubular member does not have a fixing portion fixed to the first outer tubular member.

[0006] Through the study of the present inventor, it was found that the twisting of the catheter that occurs when the conventional catheter is inserted into a meandering part in the body is mainly caused by the twisting near the second tubular member, which has a short longitudinal length. Therefore, since the second tubular member is fixed to the first outer tubular member, the vicinity of the second tubular member is less likely to twist, and as a result, the catheter is less likely to twist even when inserted into a meandering part in the body. Furthermore, in the region where the first tubular member does not have a fixed part fixed to the first outer tubular member, the first tubular member is more likely to move in the circumferential direction of the catheter when the wire is inserted into the first tubular member, which reduces the risk of the wire breaking through the first tubular member. In addition, since the twisting when the catheter is inserted into a meandering part in the body is reduced as described above, the wire is less likely to break through the catheter even when the wire is inserted into the catheter after the catheter is inserted into the meandering part.

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

[16] . [2] The catheter described in [1], wherein the second fixing portion extends in the longitudinal direction. [3] A catheter as described in [1] or [2], wherein in at least one cross section, the second tubular member has a non-contact portion that is not in contact with the first outer tubular member. [4] The catheter according to any one of [1] to [3], wherein in at least one of the cross sections, the first tubular member has a first fixed portion fixed to the second tubular member. [5] A catheter described in any of [1] to [4], wherein the distal end of the second fixing portion is located distal to the midpoint from the proximal end to the distal end of the second tubular member in the longitudinal direction, and the proximal end of the second fixing portion is located proximal to the midpoint. [6] A catheter described in any of [1] to [4], wherein the proximal end and distal end of the second fixing portion are each located proximal to the midpoint from the proximal end to the distal end in the longitudinal direction of the second tubular member. [7] A catheter described in any of [1] to [4], wherein the proximal end and distal end of the second fixing portion are each located distal to the midpoint from the proximal end to the distal end in the longitudinal direction of the second tubular member. [8] The second cylindrical member has a plurality of the second fixing portions, a distal end of the most distal second fixing portion among the plurality of second fixing portions is located distal to a midpoint from the proximal end to the distal end of the second tubular member in the longitudinal direction, The catheter according to any one of [1] to [4], wherein a proximal end of the second fixing portion that is the most proximal of the plurality of second fixing portions is located proximal to the midpoint. [9] The second cylindrical member has a plurality of the second fixing portions, A catheter described in any of [1] to [4], wherein the distal end of the most distal second fixing portion among the multiple second fixing portions and the proximal end of the most proximal second fixing portion are located proximal to the midpoint from the proximal end to the distal end in the longitudinal direction of the second tubular member.

[10] The second cylindrical member has a plurality of the second fixing portions, A catheter described in any of [1] to [4], wherein the distal end of the most distal second fixing portion among the multiple second fixing portions and the proximal end of the most proximal second fixing portion are located distal to the midpoint from the proximal end to the distal end in the longitudinal direction of the second tubular member.

[11] A catheter described in any one of [1] to [3] and [5] to

[10] , wherein the first tubular member does not have a fixing portion fixed to the first outer tubular member over the entire longitudinal length.

[12] The catheter according to any one of [1] to [3] and [5] to

[10] , wherein in at least one cross section, the first tubular member is not fixed to the second tubular member.

[13] Further, a second outer tubular member extending in the longitudinal direction, The catheter according to any one of [1] to

[12] , wherein the second outer tubular member has an inner cavity extending in the longitudinal direction, and a part of the first tubular member is disposed in the inner cavity.

[14] The catheter described in

[13] , wherein the second outer tubular member is located proximal to the proximal end of the second tubular member.

[15] A catheter as described in

[13] or

[14] , wherein the first tubular member has a non-fixed portion that is not fixed to the second outer tubular member.

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

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

[0008] According to the present invention, with the above-mentioned configuration, it is possible to provide a catheter which is less likely to twist even when inserted into a tortuous part inside the body, and in which the wire is less likely to break through. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of a catheter according to a first embodiment. [Diagram 2] FIG. 2 is a longitudinal cross-sectional view of region R1 of FIG. [Diagram 3] FIG. 3 is a longitudinal cross-sectional view of region R2 in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the catheter of FIG. 1 taken along line AA. [Diagram 5] FIG. 5 is a longitudinal cross-sectional view of region R1 of a variation of the catheter of FIG. [Figure 6] FIG. 6 is a longitudinal cross-sectional view of region R2 of a variation of the catheter of FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line AA of a modification of the catheter of FIG. [Figure 8] FIG. 8 is a side view of another variation of the catheter of FIG. [Figure 9] FIG. 9 is a cross-sectional view of the catheter of FIG. [Figure 10] FIG. 10 is a side view of the catheter according to the second embodiment. [Figure 11] FIG. 11 is a side view of a catheter according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described in more detail below based on the following embodiment, but the present invention is not limited to the following embodiment, and can be modified as long as it meets the purpose described above and below, and all of these modifications are included in the technical scope of the present invention. In addition, in each drawing, the reference numerals of the components may be omitted for convenience, and in such cases, the specification and other drawings should be referred to. In addition, the dimensions of various components in the drawings may differ from the actual dimensions, since priority is given to helping understand the features of the present invention.

[0011] A catheter according to an embodiment of the present invention 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, and a first outer tubular 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 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 second tubular member has a second fixing portion fixed to the first outer tubular member, and in at least one radial cross section including the second fixing portion, the first tubular member does not have a fixing portion fixed to the first outer tubular member.

[0012] Through the study of the present inventor, it was found that the twisting of the catheter that occurs when the conventional catheter is inserted into a meandering part in the body is mainly caused by the twisting near the second tubular member, which has a short longitudinal length. Therefore, since the second tubular member is fixed to the first outer tubular member, the vicinity of the second tubular member is less likely to twist, and as a result, the catheter is less likely to twist even when inserted into a meandering part in the body. Furthermore, in the region where the first tubular member does not have a fixed part fixed to the first outer tubular member, the first tubular member is more likely to move in the circumferential direction of the catheter when the wire is inserted into the first tubular member, which reduces the risk of the wire breaking through the first tubular member. In addition, since the twisting when the catheter is inserted into a meandering part in the body is reduced as described above, the wire is less likely to break through the catheter even when the wire is inserted into the catheter after the catheter is inserted into the meandering part.

[0013] A catheter according to a first embodiment will be described below with reference to Figs. 1 to 9. 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 an AA cross-sectional view of the catheter in Fig. 1. Fig. 5 is a longitudinal cross-sectional view of region R1 of a modified example of the catheter in Fig. 1. Fig. 6 is a longitudinal cross-sectional view of region R2 of a modified example of the catheter in Fig. 1. Fig. 7 is an AA cross-sectional view of a modified example of the catheter in Fig. 1. Fig. 8 is a side view of another modified example of the catheter in Fig. 1. Fig. 9 is a BB cross-sectional view of the catheter in Fig. 8. The shape of the AA cross-section in Fig. 8 is the same as that in Fig. 4.

[0014] As shown in FIG. 1, FIG. 2, and FIG. 3, the catheter 91 according to the first embodiment has 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. 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 guide wire into each of the lumen 1L and the lumen 2L, the catheter 91 can be guided in multiple directions, making it easier to insert the catheter 91 into various branching parts of the coronary artery, for example. In addition, by inserting a searching wire into the lumen 1L or the lumen 2L, it is easier to search for the entrance of a stenosis, which is a lesion. Of these, it is preferable to insert a searching wire into the lumen 1L.

[0015] Each of the first tubular member 1 and the second tubular member 2 preferably has one or more layers extending in the longitudinal direction X, and more preferably has multiple layers. The multiple layers preferably have an inner layer and an outer layer containing at least a part of the inner layer. The multiple layers may further have an intermediate layer located between the inner layer and the outer layer. The number of intermediate layers is not limited to one, and may be two or more. It is preferable that each of the multiple layers contains a material different from that of the adjacent layer. It is preferable that each of the inner layer of the first tubular member 1 and the inner layer of the second tubular member 2 contains at least one resin selected from the group consisting of polyolefin resins and fluorine-based resins. This can improve the sliding properties of the wires 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 having a specific gravity of 0.942 or more. The fluororesin is preferably polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinylether 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 resin, polyester resin, polyurethane resin, polyolefin resin, fluorine resin, vinyl chloride resin, silicone 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, preferably the same resin, and more preferably 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 easier to bend. 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. Of these, at least one selected from the group consisting of polyurethane and polyamide elastomer is more preferable. The polyethylene is preferably a low-density polyethylene having a specific gravity of 0.91 to 0.92.

[0017] The Shore D hardness of the material of the outer layer is preferably smaller than or equal to the Shore D hardness of the material of the inner layer, and is preferably smaller, so that the catheter 91 can be easily curved. The Shore D hardness may be measured, for example, with a durometer type D according to ISO 7619.

[0018] The intermediate layer preferably comprises a different material than the inner or outer layers, but may comprise the same material as the inner or outer layers.

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

[0020] The first cylindrical member 1 preferably includes a reinforcing member. This makes it easier to prevent the wire from breaking through the first cylindrical member 1. On the other hand, the second cylindrical member 2 preferably does not include a reinforcing member. This makes it easier to improve the flexibility of the second cylindrical member 2.

[0021] The reinforcing member is preferably a braided body in which wire is braided, a coil body in which wire is wound in a spiral shape, or a combination of these. This makes it easier to prevent the wire from breaking through the first tubular member 1. Of these, the braided body is more preferably the reinforcing member because it is easier to improve the rigidity. Examples of wires contained in the reinforcing member include metal wires and fibers. The metal wire preferably contains stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, tungsten alloy, or an alloy thereof. Of these, stainless steel is more preferable. The metal wire may be a single 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 mixture thereof. The fiber may be a monofilament or a multifilament. The reinforcing member may contain an X-ray opaque 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 wire from breaking through the first tubular member 1.

[0023] 2, the distal end 1B of the first tubular member 1 is located proximally relative to 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.

[0024] 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 a structure, for example a double tube structure (coaxial structure), 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, allowing different functions to be exhibited.

[0025] As shown in Figures 1, 2 and 3, the catheter 91 further includes a first outer tubular member 3 extending in the longitudinal direction X and having a portion that contains at least a part of the first tubular member 1 and at least a part of the second tubular member 2. Specifically, the first outer tubular member 3 has an inner cavity 3L extending in the longitudinal direction X, and it is preferable that at least a part of the first tubular member 1 and at least a part of the second tubular member 2 are disposed in the inner cavity 3L, and it is more preferable that a part of the first tubular member 1 and a part of the second tubular member 2 are disposed in the inner cavity 3L. The first outer tubular member 3 can protect the first tubular member 1 and the second tubular member 2, and can reduce the risk of the wire breaking through from inside the catheter 91.

[0026] The first outer cylindrical 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 contains at least one selected from the group consisting of polyurethane and polyamide elastomer.

[0027] As shown in FIG. 4, the cross-sectional shape of the first outer cylindrical member 3 in the radial direction Y is preferably a circle or an ellipse, but the cross-sectional shape may be a polygon with rounded corners.

[0028] As shown in Figs. 1, 2, 3, and 4, the second tubular member 2 has a second fixing portion 2F fixed to the first outer tubular member 3. This makes it difficult for the catheter 91 to twist at the second tubular member 2 and its vicinity. Examples of the fixing method include welding and adhesion. As shown in Fig. 4, the second fixing portion 2F is preferably located in the far side region 2R2 of the region 2R1 closer to the first tubular member 1 in the radial direction Y and the region 2R2 farther from the first tubular member 1. This makes it easier for the first tubular member 1 to move in the circumferential direction of the catheter 91 when the wire is inserted into the first tubular member 1, and therefore the force applied to the first tubular member 1 when the wire is inserted can be released, thereby reducing the risk of the wire breaking through the first tubular member 1. Furthermore, it is preferable that the second tubular member 2 does not have a fixing portion fixed to the first outer tubular member 3 in the region 2R1.

[0029] 4, in at least one cross section (hereinafter referred to as "cross section Y") in the radial direction Y including the second fixing portion 2F, the first tubular member 1 does not have a fixing portion fixed to the first outer tubular member 3. This makes it easier for the first tubular member 1 to move in the circumferential direction of the catheter 91 when the wire is inserted into the first tubular member 1, and as a result, the force applied to the first tubular member 1 when the wire is inserted can be released, thereby reducing the risk of the wire breaking through the first tubular member 1. The outer surface of the first tubular member 1 may be in contact with the inner surface of the first outer tubular member 3.

[0030] 1, 2 and 3, the first tubular member 1 preferably has a portion 1N extending in the longitudinal direction X. The portion 1N is a region around the entire circumference of the first tubular member 1 that does not have a fixed portion where the first tubular member 1 is fixed to the first outer tubular member 3, and the risk of the wire breaking through from the inside is reduced in the portion 1N.

[0031] 1, 2, and 3, the catheter 91 preferably has a region FN. The region FN is a region of a cross section in the radial direction Y including the second fixing portion 2F that does not have a fixing portion where the first tubular member 1 is fixed to the first outer tubular member 3. In the region FN, twisting is difficult and the risk of the wire breaking through from the inside is reduced.

[0032] 4, in cross section Y, the circumferential length of the second fixing portion 2F is preferably 0.01 to less than 0.5 times, and more preferably 0.05 to 0.2 times, the outer periphery of the second tubular member 2. This makes it difficult for the second tubular member 2 and its vicinity to twist, and allows the second tubular member 2 to move to a certain extent when the wire is inserted, thereby dissipating the force applied when the wire is inserted.

[0033] 4, in cross section Y, the second tubular member 2 preferably has a non-contact portion 2U that is not in contact with the first outer tubular member 3. This makes it easier for the first tubular member 1 to move in the circumferential direction of the catheter 91.

[0034] As shown in FIG. 1, the second fixing portion 2F preferably extends in the longitudinal direction X. This makes the catheter 91 more difficult to twist in the second tubular member 2 and its vicinity. The length of the second fixing portion 2F in the longitudinal direction X is preferably longer than the length from the distal end 1B of the first tubular member 1 to the distal end 2B of the second tubular member 2 in the longitudinal direction X. This makes the catheter 91 more difficult to twist in the second tubular member 2 and its vicinity. On the other hand, the length of the second fixing portion 2F in the longitudinal direction X may be shorter than the length from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. The second fixing portion 2F may be located proximal to the distal end 2B of the second tubular member 2, or may be located distal to the proximal end 2A of the second tubular member 2. Similarly, the region FN of the catheter 91 preferably extends in the longitudinal direction X. In the longitudinal direction X, the distal end of the region FN is preferably located proximal to or at the same position as the distal end 2FB of the second fixing portion 2F. In the longitudinal direction X, the proximal end of the region FN is preferably located distal to or at the same position as the proximal end 2FA of the second fixing portion 2F.

[0035] As shown in FIG. 1, the distal end 2FB of the second fixing part 2F is preferably located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. Furthermore, the proximal end 2FA of the second fixing part 2F is preferably located proximal to the midpoint 2N. This makes the catheter 91 even less likely to twist in the second tubular member 2 and its vicinity. The distal end 2FB of the second fixing part 2F is more preferably located distal to the distal end 1B of the first tubular member 1. The proximal end 2A of the second fixing part 2F is more preferably located proximal to a point 1 cm distally from the proximal end 2A of the second tubular member 2. Similarly, the distal end of the region FN of the catheter 91 is preferably located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. Furthermore, the proximal end of region FN is preferably located proximal to midpoint 2N.

[0036] As shown in FIG. 8, the second tubular member 2 may have a plurality of second fixing parts 2F. In this case, it is preferable that the distal end 2FB of the most distal second fixing part 2F of the plurality of second fixing parts 2F is located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2, and the proximal end 2FA of the most proximal second fixing part 2F of the plurality of second fixing parts 2F is located proximal to the midpoint 2N. This makes the catheter 91 even less likely to twist in the second tubular member 2 and its vicinity. Similarly, the catheter 91 may have a plurality of regions FN. In this case, it is preferable that the distal end of the most distal region FN of the plurality of regions FN is located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2, and the proximal end of the most proximal region FN of the plurality of regions FN is located proximal to the midpoint 2N.

[0037] 8 and 9, the second tubular member 2 may have a non-fixed portion 2G that is not fixed to the first outer tubular member 3 over the entire circumference in the circumferential direction in a portion adjacent to the second fixed portion 2F in the longitudinal direction X. The second tubular member 2 is less likely to be broken through by the wire than the first tubular member 1, but since the second tubular member 2 has the non-fixed portion 2G, the second tubular member 2 is even less likely to be broken through by the wire.

[0038] 4, in cross section Y, the first cylindrical member 1 may have a first fixing portion 1F fixed to the second cylindrical member 2. The vicinity of the first cylindrical member 1 is less prone to twisting than the vicinity of the second cylindrical member 2, but since the first cylindrical member 1 has the first fixing portion 1F, the vicinity of the first cylindrical member 1 becomes even more difficult to twist. Examples of the manner of fixing include welding and adhesion.

[0039] 5, 6, and 7, it is preferable that the first tubular member 1 is not fixed to the second tubular member 2 at cross section Y. This allows the first tubular member 1 to move more easily in the circumferential direction of the catheter 91. Examples of the manner of fixing include welding and adhesion.

[0040] Although not shown, it is preferable that the first tubular member 1 does not have a fixed portion fixed to the first outer tubular member 3 over the entire length in the longitudinal direction X. This allows the first tubular member 1 to move more easily in the circumferential direction of the catheter 91. It is also preferable that the first tubular member 1 does not have a fixed portion fixed to the second tubular member 2 over the entire length in the longitudinal direction X. This allows the first tubular member 1 to move more easily in the circumferential direction of the catheter 91. On the other hand, as shown in Figures 2 and 5, the distal end 1b of the first tubular member 1 may be fixed to the first outer tubular member 3. Furthermore, as shown in Figures 3 and 6, the first tubular member 1 may be fixed to the proximal end 3a of the first outer tubular member 3.

[0041] 2 and 5, the distal end 3B of the first outer tubular member 3 is preferably located distal to the distal end 2B of the second tubular member 2. By arranging the first outer tubular 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.

[0042] It is preferable that the length in the longitudinal direction X from the distal end 3B of the first outer tubular member 3 to the distal end 2B of the second tubular member 2 is greater than the maximum thickness of the second tubular member 2. This can improve the flexibility of the catheter 91 in the vicinity of its distal end.

[0043] 2 and 5, the distal end 3b of the first outer cylindrical member 3 is preferably fixed to the distal end 2b of the second cylindrical member 2, and more preferably fixed over the entire circumferential direction of the distal end 2b. This makes the first outer cylindrical member 3 less likely to kink or twist.

[0044] 3 and 6, the proximal end 3a of the first outer tubular member 3 is preferably fixed to the second tubular member 2. This makes the first outer tubular member 3 less likely to kink or twist. The proximal end 3a of the first outer tubular member 3 may be further fixed to the first tubular member 1.

[0045] As shown in Fig. 4, the outer surface of the first cylindrical member and the outer surface of the second cylindrical member are preferably fixed to each other by, for example, welding or adhesion.

[0046] The outer layer of the first tubular member may have a first fixed portion 1F. That is, by having a portion where the outer layer of the first tubular member is fixed to the second tubular member 2, the vicinity of the outer layer of the first tubular member becomes less likely to twist.

[0047] It is preferable that the outer layer of the second tubular member 2 has a second fixed portion 2F. That is, since the outer layer of the second tubular member 2 has a portion fixed to the first outer tubular member 3, the vicinity of the outer layer of the second tubular member 2 becomes less likely to twist.

[0048] 2 and 5, the first tubular member 1 preferably has a first opening 1E communicating with the inner cavity 1L. The first opening 1E can be used as an entrance or exit for a wire.

[0049] 2 and 5, the second tubular member 2 preferably has a second opening 2E communicating with the inner cavity 2L. The second opening 2E can be used as an entrance or exit for the wire.

[0050] The first outer cylindrical member 3 preferably has a protuberance 34 protruding in a direction away from the central axis 2C on the side closer to the first cylindrical member 1 in the radial direction Y than the distal end 1B of the first cylindrical member 1. This allows the tip of the wire inserted into the first cylindrical member 1 to be guided in a direction different from the tip of the wire inserted into the second cylindrical member 2, making it easier to treat bifurcation lesions and the like. This also makes it harder for the wires to become entangled. The protuberance 34 is preferably adjacent to the distal end 1B of the first cylindrical member 1. This makes it easier to guide the wire coming out of the first opening 1E by the protuberance 34.

[0051] As shown in FIG. 2 and FIG. 5, when a cross section in the longitudinal direction X including the central axis 1C of the first cylindrical member 1 and the central axis 2C of the second cylindrical member 2 is taken as the cross section X, the protuberance 34 preferably has a first inclined portion inclined in a direction away from the central axis 2C as it moves toward the distal side, and a second inclined portion inclined so as to approach the central axis 2C as it moves toward the distal side in the cross section X. The second inclined portion is preferably located distal to the first inclined portion. The first inclined portion makes it easier to guide the wire coming out of the first opening 1E. The second inclined portion makes it easier to insert into the body. The shape of the outer surface of the first inclined portion and the second inclined portion in the cross section X is preferably linear or curved, and 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.

[0052] On the other hand, although not shown, the first outer cylindrical 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.

[0053] As shown in FIG. 1, a handle portion 8 is preferably disposed at the proximal end 1a of the first cylindrical member 1. Specifically, the proximal end 1a of the first cylindrical member 1 is preferably disposed within the handle portion 8. The practitioner can insert the catheter 91 into the body by gripping and pushing the handle portion 8. The outer shape of the handle portion 8 may be such that the practitioner can grip it with his / her 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. Among these resins, transparent resins such as polycarbonate and polymethyl methacrylate are preferable. This makes it easier to see inside the handle portion 8, making it easier to insert the wire.

[0054] The proximal end 1A of the first tubular member 1 is preferably located within the handle portion 8. This can improve pushability.

[0055] 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. A wire can be inserted through this inner cavity.

[0056] As shown in FIG. 1, FIG. 3, and FIG. 6, the catheter 91 preferably further has a second outer cylindrical member 4 extending in the longitudinal direction X. The second outer cylindrical member 4 preferably has an inner lumen 4L extending in the longitudinal direction X, and a part of the first cylindrical member 1 is preferably disposed in the inner lumen 4L. The second outer cylindrical member 4 can form a double tube structure (coaxial structure), and can improve the transmission of the pushing force while protecting the first cylindrical member 1. The second outer cylindrical member 4 preferably has a fixed part fixed to the first cylindrical member 1 at the distal end and a non-fixed part not fixed to the first cylindrical member 1 on the proximal side of the fixed part. In addition, the second outer cylindrical member 4 preferably has a fixed part fixed to the handle part 8 at the proximal end. The cross-sectional shape of the second outer cylindrical member 4 in the radial direction Y is preferably a circle or an ellipse, but the cross-sectional shape may be a rounded polygon.

[0057] The second outer cylindrical member 4 is preferably located proximal to the proximal end 2A of the second cylindrical member 2. Specifically, the distal end of the second 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 second outer cylindrical member 4 to be reduced.

[0058] The second outer tubular member 4 preferably contains the same resin as the first outer tubular 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 second outer tubular member 4 and the proximal end of the first outer tubular member 3 are preferably fixed to each other.

[0059] 3 and 6, the first tubular member 1 preferably has a non-fixed portion 4G that is not fixed to the second outer tubular member 4. The non-fixed portion 4G is a portion that is not fixed to the second outer tubular member 4 over the entire circumferential circumference of the first tubular member 1. Since the first tubular member 1 has the non-fixed portion 4G, the first tubular member becomes more likely to move in the radial direction Y when the wire is inserted into the first tubular member, thereby reducing the risk of the wire breaking through the first tubular member.

[0060] As shown in Figures 3 and 6, the first tubular member 1 preferably has a fixed portion 4F fixed to the second outer tubular member 4 on the distal side of the non-fixed portion 4G. This can prevent the second outer tubular member 4 from becoming detached. Examples of the fixing method include welding and adhesion. It is preferable that the non-fixed portion 4G is longer than the fixed portion 4F in the longitudinal direction X. This can further reduce the risk of the wire breaking through the first tubular member.

[0061] 2 and 5, 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 away from the proximal end of the first opening 1E, which makes it easier to grasp the position of the first opening 1E.

[0062] The second tubular member 2 may have an X-ray impermeable marker 6B at a position distal to the distal end 1B of the first tubular member 1. This makes it easier to grasp the position of the curved part of the catheter 91 when inserting the catheter 91 into a tortuous part inside the body, making insertion easier.

[0063] The radiopaque marker is preferably ring-shaped. The radiopaque marker 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.

[0064] Although not shown, the catheter 91 preferably further has a linear member extending in the longitudinal direction X and at least a part of which is disposed within the second outer cylindrical member 4. This can improve the transmission of the pushing force. The linear member is preferably straight. The linear member may be one or more. 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 second outer cylindrical member 4 or the first outer cylindrical member 3. The linear member is preferably a solid member having no 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 chrome, or an alloy thereof. The linear member preferably has a constant diameter portion extending in the longitudinal direction X and having a constant outer diameter. The linear member more preferably has a tapered portion located distal to the constant diameter portion and tapered toward the distal side.

[0065] Although not shown, the catheter 91 may further have a tip extending in the longitudinal direction X. It is preferable that the tip has an inner cavity extending in the longitudinal direction X, and that at least the distal end of the second tubular member 2 is disposed within the inner cavity. This makes it easier for the tip and the second tubular member 2 to bend integrally.

[0066] At least a part of the inner surface of the tip is preferably fixed to the outer surface of the second cylindrical member 2. This makes it easier for the tip and the second cylindrical member 2 to bend integrally. Examples of the manner of fixing include welding and adhesion.

[0067] The chip 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. Among these, at least one selected from the group consisting of polyurethane and polyamide elastomer is more preferable. The polyethylene is preferably a low-density polyethylene having a specific gravity of 0.91 to 0.92.

[0068] The catheter 91 can be preferably used for treatment of dilating a stenosed or blocked portion of a passageway such as a blood vessel in the body, and can be preferably used for performing a percutaneous coronary intervention (PCI) for a bifurcation lesion of a coronary artery.

[0069] A catheter according to a second embodiment will be described below with reference to Fig. 10. Fig. 10 is a side view of a catheter according to a second embodiment. The shape of cross section AA in Fig. 10 is similar to that in Fig. 4. The shape of cross section BB in Fig. 10 is similar to that in Fig. 9. Furthermore, the shape of cross section AA in Fig. 10 may be similar to that in Fig. 7. A detailed description of parts of the catheter according to the second embodiment that overlap with the catheter according to the embodiment will be omitted.

[0070] 10, a catheter 92 according to a second embodiment includes a first tubular member 1 extending in a longitudinal direction X, a second tubular member 2 extending in the longitudinal direction X and adjacent to the first tubular member 1 in the radial direction, and a first outer tubular member 3 extending in the longitudinal direction X and having a portion including at least a part of the first tubular member 1 and at least a part of the second tubular member 2. The second tubular member 2 has a second fixing portion 2F fixed to the first outer tubular member 3, and in at least one cross section (cross section Y) of radial cross sections including the second fixing portion 2F, the first tubular member 1 does not have a fixing portion fixed to the first outer tubular member 3.

[0071] As shown in Fig. 10, in the catheter 92, the proximal end 2FA and the distal end 2FB of the second fixing portion 2F are preferably located proximal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. This makes the catheter 92 less likely to twist proximal to the midpoint 2N. Furthermore, the wire is less likely to break through the first tubular member 1 or the second tubular member 2 distal to the midpoint 2N. Similarly, the proximal end and the distal end of the region FN of the catheter 91 are preferably located proximal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2.

[0072] Although not shown, in the catheter 92, the second tubular member 2 may have a plurality of second fixing parts 2F. It is preferable that the distal end 2FB of the most distal second fixing part 2F of the plurality of second fixing parts 2F and the proximal end 2FA of the most proximal second fixing part 2F are located proximal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. This makes it difficult for the catheter 92 to twist proximal to the midpoint 2N, and makes it difficult for the wire to break through the first tubular member 1 or the second tubular member 2 distal to the midpoint 2N. Similarly, the region FN of the catheter 91 may have a plurality of regions FN. It is preferable that the distal end of the most distal region FN of the plurality of regions FN and the proximal end of the most proximal region FN are located proximal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2.

[0073] A catheter according to a third embodiment will be described below with reference to Fig. 11. Fig. 11 is a side view of a catheter according to a third embodiment. The shape of the AA cross section in Fig. 11 is similar to that in Fig. 4. The shape of the BB cross section in Fig. 11 is similar to that in Fig. 9. Furthermore, the shape of the AA cross section in Fig. 11 may be similar to that in Fig. 7. A detailed description of parts of the catheter according to the third embodiment that overlap with the catheter according to the embodiment will be omitted.

[0074] 11, a catheter 93 according to a third embodiment includes a first tubular member 1 extending in a longitudinal direction X, a second tubular member 2 extending in the longitudinal direction X and adjacent to the first tubular member 1 in the radial direction, and a first outer tubular member 3 extending in the longitudinal direction X and having a portion including at least a part of the first tubular member 1 and at least a part of the second tubular member 2. The second tubular member 2 has a second fixing portion 2F fixed to the first outer tubular member 3, and in at least one cross section (cross section Y) among radial cross sections including the second fixing portion 2F, the first tubular member 1 does not have a fixing portion fixed to the first outer tubular member 3.

[0075] As shown in Fig. 11, in the catheter 93, the proximal end 2FA and the distal end 2FB of the second fixing part 2F are preferably located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. This makes the catheter 93 less likely to twist distal to the midpoint 2N. Furthermore, the wire is less likely to break through the first tubular member 1 or the second tubular member 2 proximal to the midpoint 2N. Similarly, the proximal end and the distal end of the region FN of the catheter 91 are preferably located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2.

[0076] Although not shown, in the catheter 93, the second tubular member 2 may have a plurality of second fixing parts 2F. It is preferable that the distal end 2FB of the most distal second fixing part 2F among the plurality of second fixing parts 2F and the proximal end 2FA of the most proximal second fixing part 2F are located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. This makes it difficult for the catheter 93 to twist distal to the midpoint 2N. Furthermore, it is difficult for the wire to break through the first tubular member 1 or the second tubular member 2 proximal to the midpoint 2N. Similarly, the region FN of the catheter 91 may have a plurality of regions FN. It is preferable that the distal end of the most distal region FN among the multiple regions FN and the proximal end of the most proximal region FN are located distal to the midpoint 2N from the proximal end 2A to the distal end 2B in the longitudinal direction X of the second tubular member 2. [Explanation of symbols]

[0077] 1 First cylindrical member 1a Proximal end 1b Distal end 1A proximal end 1B Distal end 1C center axis 1E 1st opening 1F 1st fixed part 1L lumen 1N Part not having a fixed part 2 Second cylindrical member 2a Proximal end 2b Distal end 2A Proximal End 2B Distal end 2C center axis 2E 2nd opening 2F 2nd fixed part 2FA proximal end 2FB Distal End 2L lumen 2N midpoint 2U non-contact part 3 First outer cylindrical member 3a Proximal end 3b Distal end 3B Distal end 3L lumen 4 Second outer cylindrical member 4F Fixed part 4G non-fixed part 4L lumen 6A, 6B Radiopaque markers 8 Handle 34 Ridge 91, 92, 93 Catheters X Longitudinal direction Y radial direction FN area

Claims

1. A first tubular member extending in a longitudinal direction; a second cylindrical member extending in the longitudinal direction and adjacent to the first cylindrical member in a radial direction; a first outer tubular 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, 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; the second tubular member has a second fixing portion fixed to the first outer tubular member, A catheter in which, in at least one of the radial cross sections including the second fixing portion, the first tubular member does not have a fixing portion fixed to the first outer tubular member.

2. The catheter according to claim 1 , wherein the second fixation portion extends in the longitudinal direction.

3. The catheter according to claim 1 or 2, wherein in at least one of the cross sections, the second tubular member has a non-contact portion that is not in contact with the first outer tubular member.

4. The catheter according to claim 1 or 2, wherein the first tubular member has a first fixing portion fixed to the second tubular member in the at least one cross section.

5. 3. The catheter according to claim 1 or 2, wherein the distal end of the second fixing portion is located distal to a midpoint of the longitudinal direction of the second tubular member from the proximal end to the distal end, and the proximal end of the second fixing portion is located proximal to the midpoint.

6. The catheter according to claim 1 or 2, wherein the proximal end and the distal end of the second fixing portion are each located proximal to a midpoint of the longitudinal direction of the second tubular member from the proximal end to the distal end.

7. The catheter according to claim 1 or 2, wherein the proximal end and the distal end of the second fixing portion are each located distal to a midpoint of the longitudinal direction of the second tubular member from the proximal end to the distal end.

8. The second tubular member has a plurality of the second fixing portions, a distal end of the most distal second fixing portion among the plurality of second fixing portions is located distal to a midpoint from the proximal end to the distal end of the second tubular member in the longitudinal direction, The catheter according to claim 1 or 2, wherein a proximal end of the second fixing portion that is the most proximal of the plurality of second fixing portions is located proximal to the midpoint.

9. The second tubular member has a plurality of the second fixing portions, 3. The catheter of claim 1, wherein the distal end of the most distal of the plurality of second fixing portions and the proximal end of the most proximal of the second fixing portions are located proximal to the midpoint from the proximal end to the distal end in the longitudinal direction of the second tubular member.

10. The second tubular member has a plurality of the second fixing portions, 3. The catheter of claim 1, wherein the distal end of the most distal of the plurality of second fixing portions and the proximal end of the most proximal of the second fixing portions are located distal to the midpoint from the proximal end to the distal end in the longitudinal direction of the second tubular member.

11. The catheter according to claim 1 or 2, wherein the first tubular member does not have a fixing portion fixed to the first outer tubular member over the entire length in the longitudinal direction.

12. The catheter according to claim 1 or 2, wherein the first tubular member is not fixed to the second tubular member in the at least one cross section.

13. a second outer tubular member extending in the longitudinal direction; The catheter according to claim 1 or 2, wherein the second outer tubular member has an inner cavity extending in the longitudinal direction, and a portion of the first tubular member is disposed in the inner cavity.

14. The catheter of claim 13 , wherein the second outer tubular member is located proximal to the proximal end of the second tubular member.

15. The catheter according to claim 13 , wherein the first tubular member has a non-fixed portion that is not fixed to the second outer tubular member.

16. 3. The catheter according to claim 1, wherein a handle portion is disposed at a proximal end of the first tubular member.

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