Extension catheter

Abstract

Provided is an extension catheter easy to insert into a curved part inside a body. This extension catheter is inserted into a catheter and can protrude from a distal-side opening of the catheter. The extension catheter comprises a cylindrical member and a linear member having a distal end portion fixed to the cylindrical member. The linear member has, on a side surface thereof, a first cut surface facing outward in the radial direction of the cylindrical member.

Description

Extension catheter

[0001] The present invention relates to an extension catheter.

[0002] To date, percutaneous coronary intervention (PCI) has been performed to treat ischemic heart diseases such as angina pectoris and myocardial infarction by dilating narrowed portions of the coronary arteries of the heart using intravascular treatment devices such as stents and balloons to increase blood flow. In this procedure, the tip of a guiding catheter is inserted into the entrance of the coronary artery and left there, and then an extension catheter is inserted through a proximal opening of the guiding catheter, with a portion of the extension catheter protruding from a distal opening and inserted into the coronary artery. Use of such an extension catheter facilitates delivery of an intravascular treatment device to the affected area within the coronary artery. Various such extension catheters are known, and for example, Patent Document 1 discloses an extension catheter that includes a tubular portion, a first tapered portion located proximal to the tubular portion, and a second tapered portion located proximal to the first tapered portion, wherein the first tapered portion has an outer surface and a first tapered surface, and the second tapered portion has an outer surface and a second tapered surface, and the angle θ1 between the first tapered surface and the axial direction of the tubular portion is 90 to 145°, and the angle θ2 between the second tapered surface and the axial direction is 120 to 175°.

[0003] International Publication No. 2020 / 162286

[0004] With conventional extension catheters such as those disclosed in Patent Document 1, it has sometimes been difficult to insert the tubular member fixed to the distal end of the linear member into a curved portion of an artery or the like inside the body. The present invention has been made in light of the above-mentioned circumstances, and its object is to provide an extension catheter that is easy to insert into a curved portion inside the body.

[0005] Extension catheters according to embodiments that can solve the above problems are as follows: [1] An extension catheter that is inserted into a catheter and can protrude from an opening on the distal side of the catheter, the extension catheter having a tubular member and a linear member having a distal end fixed to the tubular member, the linear member having a first cutting surface on a side surface that faces outward in the radial direction of the tubular member.

[0006] Through research by the present inventors, it has been found that, in manufacturing an extension catheter, if the distal end of a linear member is cut to reduce its outer diameter and then the cut surface is fixed facing a tubular member, residual stress from the cutting causes the cut surface of the linear member and its vicinity to bend more easily in a direction away from the central axis of the tubular member. On the other hand, in a configuration in which the cut surface of the linear member faces away from the tubular member, i.e., faces outward in the radial direction of the tubular member, as in [1] above, it has been found that residual stress from the cutting causes the cut surface and its vicinity to bend more easily in a direction toward the central axis of the tubular member. With this configuration, when the tubular member is pushed into a curved portion within the body via the linear member, the linear member and the tubular member are more likely to bend along the shape of the curved portion within the body, making it easier to insert the extension catheter into the curved portion within the body. An extension catheter according to an embodiment is preferably any one of the following [2] to

[18] . [2] The extension catheter according to [1], wherein at least a portion of the first cut surface is located at the distal end. [3] The extension catheter according to [1] or [2], wherein the linear member has a plurality of cutting surfaces on the side surface, and the first cutting surface is the cutting surface with the largest area between the distal end of the linear member and a position 20 cm away from the proximal side. [4] The extension catheter according to any one of [1] to [3], wherein the linear member does not have a cutting surface facing inward in the radial direction, at least in a portion fixed to the tubular member. [5] The extension catheter according to any one of [1] to [4], wherein the first cutting surface is inclined with respect to the axial direction of the tubular member, and the distal end of the first cutting surface is located more inward in the radial direction than the proximal end. [6] The extension catheter according to any one of [1] to [5], wherein the first cutting surface does not have a portion that is parallel to the axial direction of the tubular member. [7] The extension catheter according to any one of [3] to [6], wherein the proximal end of the cutting surface located most proximal of the plurality of cutting surfaces is located more proximal than the proximal end of the tubular member.[8] The extension catheter according to any one of [1] to [7], wherein the linear member has a first portion including the first cutting surface and a second portion located proximal to the first portion and not having a cutting surface on the side surface, and wherein, in a cross section of the linear member in the radial direction of the tubular member, the first portion has a larger ratio of the major axis to the minor axis than the second portion. [9] The extension catheter according to [8], wherein the proximal end of the first portion is located proximal to the proximal end of the tubular member.

[10] The extension catheter according to [8] or [9], wherein the length of the first portion is 10% or less of the length of the linear member.

[11] The extension catheter according to any one of [8] to

[10] , wherein the first portion is located between the distal end of the tubular member and a position that is 20 cm or more and 40 cm or less from the distal end of the tubular member.

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

[11] , wherein the tubular member has a reinforcing layer.

[13] The extension catheter according to

[12] , wherein the distal end of the linear member is located distally of the proximal end of the reinforcing layer.

[14] The extension catheter according to

[12] , wherein the distal end of the linear member is located proximally of the proximal end of the reinforcing layer.

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

[14] , wherein the tubular member has a tubular portion and a tapered portion located proximally of the tubular portion.

[16] The extension catheter according to

[15] , wherein the distal end of the first cutting surface is located at the distal end of the linear member, and the distal end of the tapered portion of the tubular member is located proximally of the distal end of the first cutting surface and distal to the proximal end of the first cutting surface.

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

[16] , wherein the linear member is a solid linear member having no lumen.

[18] The extension catheter according to any one of

[15] to

[17] , wherein a proximal end of the tapered surface of the tapered portion is closer to the linear member than a distal end of the tapered surface in the radial direction of the tubular member.

[0007] According to the present invention, an extension catheter that can be easily inserted into curved parts inside the body can be provided.

[0008] FIG. 1 is a side view of an extension catheter according to an embodiment. FIG. 2 is a side view of the extension catheter of FIG. 1 inserted into a guiding catheter with a portion protruding from the distal opening. FIG. 3 is an axial cross-sectional view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 4 is a IV-IV cross-sectional view of the extension catheter of FIG. 1. FIG. 5 is a V-V cross-sectional view of the extension catheter of FIG. 1. FIG. 6 is a side view of the extension catheter of FIG. 1 inserted into a curved guiding catheter. FIG. 7 is a side view of a modified linear member of the extension catheter of FIG. 1. FIG. 8 is a side view of a modified linear member of the extension catheter of FIG. 1. FIG. 9 is a IX-IX cross-sectional view of the extension catheter of FIG. 1. FIG. 10 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 11 is a side view of the extension catheter of FIG. 1 having a radiopaque ring.

[0009] 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.

[0010] An extension catheter according to an embodiment is an extension catheter that is inserted into a catheter and can protrude from an opening on the distal side of the catheter, and includes a tubular member and a linear member whose distal end is fixed to the tubular member, the linear member having a first cutting surface on its side that faces outward in the radial direction of the tubular member. The inventors' studies have revealed that, in manufacturing an extension catheter, if the distal end of the linear member is cut to reduce its outer diameter and then the cut surface is fixed toward the tubular member, residual stress from the cutting makes the cut surface of the linear member and its vicinity more likely to bend in a direction away from the central axis of the tubular member. On the other hand, as described above, in a configuration in which the cut surface of the linear member faces the opposite side from the tubular member, i.e., toward the outside in the radial direction of the tubular member, residual stress from the cutting has been found to make the cut surface and its vicinity more likely to bend in a direction toward the central axis of the tubular member. With this configuration, when the tubular member is pushed into a curved portion inside the body via the linear member, the linear member and the tubular member tend to curve along the shape of the curved portion inside the body, making it easier to insert the extension catheter into the curved portion inside the body.

[0011] 1 to 11 , extension catheters according to embodiments will be described. FIG. 1 is a side view of an extension catheter according to an embodiment. FIG. 2 is a side view of the extension catheter of FIG. 1 inserted into a guiding catheter with a portion protruding from the distal opening. FIG. 3 is an axial cross-sectional view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIGS. 4, 5, and 9 are cross-sectional views of the extension catheter of FIG. 1 taken along lines IV-IV, V-V, and IX-IX, respectively. FIG. 6 is a side view of the extension catheter of FIG. 1 inserted into a guiding catheter in a curved state. FIGS. 7 and 8 are side views of modified examples of the linear member of the extension catheter of FIG. 1, respectively. FIG. 10 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 11 is a side view of the extension catheter of FIG. 1 having a radiopaque ring.

[0012] 1, an extension catheter 91 according to this embodiment has a tubular member 1 and a linear member 2 having a distal end 2B fixed to the tubular member 1. This allows the operator to push the tubular member 1 distally or pull it back proximally via the linear member 2.

[0013] As shown in FIG. 2 , the extension catheter 91 is inserted into the catheter 99 and can protrude from a distal opening 99Pb of the catheter 99. For example, after the distal end of the catheter 99 is inserted into the entrance of a coronary artery and left there, the extension catheter 91 is inserted into the catheter 99 from a proximal opening 99Pa of the catheter 99, and a portion of the extension catheter 91 protrudes from the distal opening 99Pb of the catheter 99 and is inserted into the coronary artery. This allows an intravascular treatment device to be delivered to an affected area in the coronary artery via the catheter 99 and the extension catheter 91. Examples of intravascular treatment devices include a balloon and a stent. The catheter 99 is preferably a so-called guiding catheter. A guiding catheter has a lumen into which a treatment catheter such as a balloon catheter or a stent delivery catheter is inserted. The treatment catheter is preferably one that is inserted into a coronary artery, but may also be one that is inserted into other arteries such as cerebral arteries, veins, pancreatic ducts, bile ducts, ureters, bronchi, or other internal body ducts. It is preferable that the catheter 99 does not have a through-hole, groove, or the like that penetrates from the outer surface to the inner surface, which makes it easier to insert the extension catheter 91 from the opening 99Pa on the proximal side of the catheter 99 and have a portion of it protrude from the opening 99Pb on the distal side.

[0014] 3, 4, and 5, the linear member 2 has a first cutting surface 2S1 on its side surface that faces the outer side 1D1 in the radial direction 1D of the tubular member 1. Due to residual stress generated when forming the first cutting surface 2S1 in the linear member 2, the first cutting surface 2S1 and its vicinity tend to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1. As a result, as shown in FIG. 6, when the tubular portion 10 is pushed into a curved portion inside a body via the linear member 2, the tubular portion 10 and the linear member 2 tend to bend along the shape of the curved portion, making it easier to insert the extension catheter 91 into the curved portion inside the body. The first cutting surface 2S1 facing the outer side 1D1 in the radial direction 1D of the tubular member 1 means that the first cutting surface 2S1 faces in the opposite direction to the direction toward the central axis 1C of the tubular member 1 in the radial direction 1D of the tubular member 1. On the other hand, the first cutting surface 2S1 facing the inner side 1D2 in the radial direction 1D of the cylindrical member 1 means that the first cutting surface 2S1 faces a direction toward the central axis 1C of the cylindrical member 1 in the radial direction 1D of the cylindrical member 1. Hereinafter, the radial direction 1D of the cylindrical member 1 may be simply referred to as the radial direction 1D.

[0015] 3, it is preferable that at least a portion of the first cutting surface 2S1 is located at the distal end 2B of the linear member 2. This makes it easier for the portion of the tubular member 1 to which the distal end 2B of the linear member 2 is fixed to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1.

[0016] The distal end 2S1b of the first cutting surface 2S1 is preferably located at the distal end 2b of the linear member 2. This makes it easier to bend the linear member 2 from the distal end 2b.

[0017] The proximal end 2S1a of the first cutting surface 2S1 is preferably located more proximal than the proximal end 1a of the tubular member 1. This makes it easier for the portion of the tubular member 1 to which the distal end 2B of the linear member 2 is fixed to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1.

[0018] The first cutting surface 2S1 is inclined with respect to the axial direction 1X of the tubular member 1, and it is preferable that the distal end 2S1b of the first cutting surface 2S1 is located more inward than the proximal end 2S1a in the radial direction 1D. By inclining the first cutting surface 2S1 in this manner, the first cutting surface 2S1 of the linear member 2 and its vicinity become more likely to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1.

[0019] It is preferable that the first cutting surface 2S1 does not have a portion that is parallel to the axial direction 1X of the cylindrical member 1. This makes it easier for the first cutting surface 2S1 of the linear member 2 and its vicinity to bend toward the inside 1D2 in the radial direction 1D of the cylindrical member 1.

[0020] As shown in FIG. 7 , the linear member 2 may have multiple cutting surfaces on its side surface. In this case, the multiple cutting surfaces preferably include a first cutting surface 2S1 located most distally among the multiple cutting surfaces and a second cutting surface 2S2 located proximal to the first cutting surface 2S1. The first cutting surface 2S1 and the second cutting surface 2S2 preferably face the outer side 1D1 in the radial direction 1D of the tubular member 1. The angles formed by the first cutting surface 2S1 and the second cutting surface 2S2 with the axial direction 2X of the linear member 2 are preferably 0.1° or more and 45° or less, more preferably 0.2° or more and 30° or less, and even more preferably 0.2° or more and 5° or less. The angle formed by the first cutting surface 2S1 and the axial direction 2X of the linear member 2 is preferably smaller than the angle formed by the second cutting surface 2S2 with the axial direction 2X of the linear member 2. Furthermore, it is preferable that the first cutting surface 2S1 is longer than the second cutting surface 2S2 in the axial direction 2X of the linear member 2. This increases the area of ​​the first cutting surface 2S1, making it easier for the linear member 2 to bend at curved portions within the body. On the other hand, the angle formed between the first cutting surface 2S1 and the axial direction 2X of the linear member 2 may be larger than the angle formed between the second cutting surface 2S2 and the axial direction 2X of the linear member 2. Furthermore, in the axial direction 2X of the linear member 2, the first cutting surface 2S1 may be shorter than the second cutting surface 2S2. This improves the strength of the linear member 2 in the vicinity of the distal end 2b.

[0021] 7, it is preferable that the multiple cutting surfaces each face toward the outside 1D1 in the radial direction 1D of the tubular member 1, are inclined with respect to the axial direction 1X of the tubular member 1, and that the distal end of each cutting surface is located more inward than the proximal end in the radial direction 1D. This makes it easier for the multiple cutting surfaces of the linear member 2 and their vicinity to bend toward the inside 1D2 in the radial direction 1D of the tubular member 1. Note that the multiple cutting surfaces may have cutting surfaces that are parallel to the axial direction 1X of the tubular member 1.

[0022] It is preferable that the proximal end of the cutting surface located most proximally among the plurality of cutting surfaces is located more proximal than the proximal end 1a of the tubular member 1. For example, as shown in Figure 7, when the plurality of cutting surfaces have a first cutting surface 2S1 and a second cutting surface 2S2 located more proximal than the first cutting surface 2S1, it is preferable that the proximal end 2S2a of the second cutting surface 2S2 is located more proximal than the proximal end 1a of the tubular member 1. This makes it easier for the portion of the tubular member 1 to which the distal end portion 2B of the linear member 2 is fixed to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1.

[0023] The first cutting surface 2S1 is preferably the cutting surface with the largest area between the distal end 2b of the linear member 2 and a position 20 cm proximally away from the distal end 2b. This makes it easier for the distal end portion 2B of the linear member 2 to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1.

[0024] 3, 4, and 5, it is preferable that the linear member 2 does not have a cutting surface facing the inner side 1D2 in the radial direction 1D at least in the portion fixed to the tubular member 1. This makes it even easier for the distal end portion 2B of the linear member 2 to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1.

[0025] On the other hand, as shown in FIG. 8 , the linear member 2 may have an inward cutting surface 2S3 facing the inner side 1D2 in the radial direction 1D. In this case, as shown in FIG. 8 , the length H1 of the first cutting surface 2S1 in the radial direction 1D is preferably longer than the length H3 of the inward cutting surface 2S3 in the radial direction 1D. In this configuration, the residual stress toward the inner side 1D2 in the radial direction 1D of the tubular member 1 is greater than the residual stress toward the outer side 1D1 in the radial direction 1D of the tubular member 1, so the first cutting surface 2S1 and its vicinity are more likely to bend toward the inner side 1D2 in the radial direction 1D of the tubular member 1. At least a portion of the inward cutting surface 2S3 is preferably located at the distal end 2B of the linear member 2. Furthermore, the distal end 2S3b of the inward cutting surface 2S3 is preferably located at the distal end 2b of the linear member 2. This allows the outer diameter of the linear member 2 to be reduced at the distal end 2b and its vicinity.

[0026] As shown in Figures 1 and 3, the linear member 2 preferably has a first portion 2P1 including a first cutting surface 2S1 and a second portion 2P2 located proximal to the first portion 2P1 and not having a cutting surface on its side. Furthermore, as shown in Figures 4, 5, and 9, in a cross section of the linear member 2 in the radial direction 1D of the tubular member 1, the first portion 2P1 preferably has a larger ratio of the major axis to the minor axis than the second portion 2P2. Since a larger ratio of the major axis to the minor axis makes the linear member 2 more likely to bend in one direction and exhibit anisotropy, a larger ratio of the major axis to the minor axis of the first portion 2P1 makes it easier to insert the linear member 2 into a curved portion inside the body from its distal side. The minor axis is the length of the shortest line segment connecting two points on the outer edge of the linear member 2 in each cross section and passing through the centroid of the linear member 2. The major axis is the length of the longest line segment that connects two points on the outer edge of the linear member 2 in each cross section and passes through the centroid of the linear member 2. The first portion 2P1 may have multiple cutting surfaces.

[0027] 1 and 3, the proximal end 2P1a of the first portion 2P1 is preferably located more proximal than the proximal end 1a of the tubular member 1. This makes it easier for the portion of the tubular member 1 to which the distal end 2B of the linear member 2 is fixed to bend toward the inside 1D2 in the radial direction 1D of the tubular member 1.

[0028] The length of the first portion 2P1 is preferably 10% or less of the length of the linear member 2. This allows the length of the anisotropic portion of the linear member 2 to be reduced, making it easier to push the linear member 2 into, for example, a straight portion of a blood vessel. The length of the first portion 2P1 is more preferably 9% or less of the length of the linear member 2. On the other hand, the length of the first portion 2P1 is preferably 1% or more, and more preferably 2% or more, of the length of the linear member 2. This allows the distal side of the linear member 2 to be more easily inserted into a curved portion inside the body.

[0029] The first portion 2P1 is preferably located between the distal end 1b of the tubular member 1 and a position that is 20 cm or more and 40 cm or less from the distal end 1b of the tubular member 1. By positioning the first portion 2P1 in at least a part of this range, it becomes easier to insert the tubular member 1 into a curved portion inside the body.

[0030] As shown in Figures 4, 5, and 9, the linear member 2 is preferably a solid linear member without an internal cavity, which allows the thickness of the linear member 2 to be reduced. The material of the linear member 2 is not particularly limited as long as it can push the tubular member 1 distally, but preferably includes stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, tungsten alloy, or a combination thereof, and more preferably includes stainless steel.

[0031] The cut surface on the side surface of the linear member 2 can be formed, for example, by grinding the side surface of a wire rod having a circular cross section in the thickness direction with a grinding machine. The cross section in the thickness direction of the wire rod is not limited to a circle, and may be, for example, a polygon, an ellipse, or the like.

[0032] The cross-sectional shape of the linear member 2 in the thickness direction is preferably a convex polygon, a concave polygon, a circle, a D-shape, or an ellipse. The convex polygon may be a square, a rectangle, a trapezoid, or a hexagon. The cross-sectional shape of the linear member 2 in the first portion 2P1 in the thickness direction is preferably a D-shape, a rectangle, or an ellipse. This makes it easier for the first portion 2P1 to exhibit anisotropy. On the other hand, the cross-sectional shape of the linear member 2 in the second portion 2P2 is preferably a circle or a regular polygon. This makes it harder for the second portion 2P2 to exhibit anisotropy.

[0033] 4 and 9, it is preferable that the cross-sectional shapes in the thickness direction of the linear member 2 are different between the first portion 2P1 and the second portion 2P2, which makes it easier for the first portion 2P1 and the second portion 2P2 to exhibit their respective functions.

[0034] 4 and 9, the cross-sectional area of ​​the first portion 2P1 in the thickness direction of the linear member 2 is preferably smaller than the cross-sectional area of ​​the second portion 2P2 in the thickness direction of the linear member 2. This makes the first portion 2P1 more likely to bend.

[0035] As shown in Figure 1, the extension catheter 91 preferably further includes a handle member 3 fixed to the proximal end of the linear member 2. An operator can grasp the handle member 3 to move the linear member 2 distally or proximally. The handle member 3 preferably includes a resin. The resin is preferably a polyolefin resin. The polyolefin resin preferably includes polyethylene, polypropylene, or a combination thereof.

[0036] As shown in FIGS. 1 and 10 , the tubular member 1 preferably has a tubular portion 10 and a tapered portion 11 located proximal to the tubular portion 10. The tapered portion 11 has a length in a radial direction 1D of the tubular member 1 that is shorter than the tubular portion 10, and has an opening 11P that communicates with the lumen of the tubular member 1 and faces the radial direction 1D. The tapered portion 11 has at least one tapered surface that is inclined with respect to the axial direction 10X of the tubular portion 10. This facilitates insertion of an intravascular treatment device into the lumen of the tubular member 1 through the opening 11P of the tapered portion 11 of the tubular member 1 that has been inserted into a curved portion inside a body, as shown in FIG. 6 , for example. A treatment catheter such as a balloon catheter or a stent delivery catheter may be used to insert the intravascular treatment device into the opening 11P.

[0037] As shown in FIG. 10 , the tapered portion 11 of the tubular member 1 preferably has multiple tapered surfaces. The multiple tapered surfaces preferably include a first tapered surface S1 located most distally among the multiple tapered surfaces. The angle θ1 between the first tapered surface S1 and the axial direction 10X of the tubular portion 10 is preferably 20° or greater, more preferably 30° or greater. This reduces the thin-walled portion near the distal end 11b of the tapered portion 11 as shown in FIG. 3 , making it less likely that an intravascular treatment device will get caught near the distal end 11b of the tapered portion 11. On the other hand, the angle θ1 is preferably 89° or less, more preferably 85° or less. This increases the opening area of ​​at least the opening 11P located inside the first tapered surface S1. Note that the tapered portion 11 of the tubular member 1 may have only one tapered surface.

[0038] As shown in FIG. 10 , the multiple tapered surfaces of the tapered portion 11 preferably include a first tapered surface S1 and a second tapered surface S2 located proximal to the first tapered surface S1. The angle of the second tapered surface S2 with respect to the axial direction 10X of the tubular portion 10 is preferably smaller than the angle θ1 between the first tapered surface S1 and the axial direction 10X of the tubular portion 10. This allows for a larger opening area of ​​the opening 11P. The angle between the second tapered surface S2 and the axial direction 10X of the tubular portion 10 is preferably less than 85°, and more preferably 80° or less. This allows for a larger opening area of ​​the opening 11P. Meanwhile, this angle is preferably 10° or greater, and more preferably 20° or greater. This reduces the risk of the intravascular treatment device shaking when inserted into the opening 11P.

[0039] As shown in FIG. 10 , the tapered surface of the tapered portion 11 preferably includes a first tapered surface S1, a second tapered surface S2 located proximal to the first tapered surface S1, and a third tapered surface S3 located proximal to the second tapered surface S2. The angle between the third tapered surface S3 and the axial direction 10X of the tubular portion 10 is preferably smaller than the angle between the second tapered surface S2 and the axial direction 10X of the tubular portion 10. This allows for a larger area of ​​the opening 11P. The angle between the third tapered surface S3 and the axial direction 10X of the tubular portion 10 is preferably 5° or less, more preferably 2° or less, and most preferably 0°. The third tapered surface S3 preferably includes the proximal end 11a of the tapered portion 11. The first tapered surface S1 and the second tapered surface S2 are preferably adjacent to each other. The second tapered surface S2 and the third tapered surface S3 are preferably adjacent to each other. The multiple tapered surfaces of the tapered portion 11 may be composed of a first tapered surface S1 and a second tapered surface S2, or may be composed of a first tapered surface S1 and a third tapered surface S3, or may be composed of a second tapered surface S2 and a third tapered surface S3. The tapered surfaces of the tapered portion 11 of the tubular member 1 can be formed by making an incision in the proximal end of the tubular body using a cutting tool such as a cutter and removing a portion of the proximal end of the tubular body.

[0040] As shown in FIG. 10 , in a field of view in which the tubular member 1 is oriented so that the tapered surface of the tapered portion 11 is linear, the first tapered surface S1, the second tapered surface S2, and the third tapered surface S3 are preferably linear or curved, and more preferably linear. Having linear tapered surfaces improves manufacturing efficiency. When the first tapered surface S1 is curved in this field of view, the angle θ1 between the first tapered surface S1 and the axial direction 10X of the tubular portion 10 is the angle between the line connecting the proximal end S1a and the distal end S1b of the first tapered surface S1 and the axial direction 10X. Similarly, when the second tapered surface S2 and the third tapered surface S3 are curved in this field of view, the angle between each surface and the axial direction 10X of the tubular portion 10 is the angle between the line connecting the proximal end and the distal end of each surface and the axial direction 10X.

[0041] The second tapered surface S2 is preferably the tapered surface with the largest area among the multiple tapered surfaces that are inclined at an angle of more than 5° and not more than 89° with respect to the axial direction 10X of the tubular portion 10. In Fig. 10, the first tapered surface S1 and the second tapered surface S2 are inclined at an angle of more than 5° and not more than 89° with respect to the axial direction 10X of the tubular portion 10, and of these, the second tapered surface S2 has the largest area. This makes it easier to obtain the effect of the inclination of the second tapered surface S2 described above.

[0042] It is preferable that the second tapered surface S2 has the longest length in the radial direction 1D of the cylindrical member 1 among the multiple tapered surfaces. In Fig. 10, among the first tapered surface S1, the second tapered surface S2, and the third tapered surface S3, the second tapered surface S2 has the longest length in the radial direction 1D. This makes it easier to obtain the effect of the inclination of the second tapered surface S2 described above.

[0043] As shown in Fig. 10 , in the radial direction 1D of the tubular member 1, the proximal end of the tapered surface of the tapered portion 11 is preferably closer to the linear member 2 than the distal end of the tapered surface. Specifically, the proximal end S1a of the first tapered surface S1 is preferably closer to the linear member 2 than the distal end S1b of the first tapered surface S1. This inclination of the first tapered surface S1 facilitates insertion of an intravascular treatment device through at least an opening 11P located inside the first tapered surface S1. Furthermore, in the radial direction 1D of the tubular member 1, the proximal end of the second tapered surface S2 is preferably closer to the linear member 2 than the distal end of the second tapered surface S2. The proximal end of the third tapered surface S3 may be closer to the linear member 2 than the distal end of the third tapered surface S3, but it is preferable that the third tapered surface S3 be parallel to the linear member 2.

[0044] 3, it is preferable that the distal end 2S1b of the first cutting surface 2S1 is located at the distal end 2b of the linear member 2, and the distal end 11b of the tapered portion 11 of the tubular member 1 is located proximal to the distal end 2S1b of the first cutting surface 2S1 and distal to the proximal end 2S1a of the first cutting surface 2S1. This makes it easier for the tubular portion 10 and the tapered portion 11 to bend in that order when the tubular member is pushed into a curved portion inside the body via the linear member 2.

[0045] 3, the tubular member 1 preferably has an inner layer 10L and an outer layer 10M located outside the inner layer 10L in the radial direction 1D. By having the inner layer 10L and the outer layer 10M, the tubular member 1 can exhibit different functions on the inside and outside.

[0046] The inner layer 10L preferably contains a fluororesin, more preferably is made of a fluororesin, which has excellent chemical resistance, non-stick properties, and low friction. The fluororesin preferably contains polytetrafluoroethylene, ethylene tetrafluoroethylene, fluorinated ethylene propylene, or a combination thereof.

[0047] The outer layer 10M preferably contains a polyamide resin, a polyester resin, a polyurethane resin, a polyolefin resin, a vinyl chloride resin, a silicone resin, a natural rubber, or a combination thereof, and more preferably contains a polyamide resin, a polyurethane resin, or a combination thereof. The resin may contain an elastomer having rubber elasticity. For example, the polyamide resin may contain a polyamide elastomer, and the polyurethane resin may contain a polyurethane elastomer.

[0048] The outer layer 10M may have a plurality of layers stacked in the radial direction. Among the plurality of layers, radially adjacent layers may contain different types of resin or may contain the same type of resin.

[0049] The outer layer 10M preferably has a hydrophilic polymer on its outer surface. This makes it easier to insert the tubular member 1 into a guiding catheter or a blood vessel. The hydrophilic polymer preferably includes poly (2-hydroxyethyl methacrylate), polyacrylamide, polyvinylpyrrolidone, maleic anhydride copolymer, or a combination thereof. The maleic anhydride copolymer is preferably a methyl vinyl ether maleic anhydride copolymer.

[0050] The distal end 2B of the linear member 2 is preferably disposed between the inner layer 10L and the outer layer 10M or within the outer layer 10M in the radial direction 1D of the tubular member 1. This makes it easier to firmly fix the linear member 2 to the tubular member 1. An adhesive such as a hot melt adhesive may be attached to the outer surface of the linear member 2.

[0051] The inner layer 10L and the outer layer 10M preferably extend in the axial direction 10X from the cylindrical portion 10 to the tapered portion 11. This facilitates smooth curvature in the order from the cylindrical portion 10 to the tapered portion 11.

[0052] The tubular member 1 preferably does not have through holes, grooves, etc. that penetrate the outer and inner surfaces of the tubular portion 10, the tapered portion 11, or both of them. This makes it less likely that an intravascular treatment device will get caught inside the tubular member 1 when being delivered. Furthermore, the tubular member 1 preferably does not have non-penetrating grooves on the outer surfaces of the tubular portion 10, the tapered portion 11, or both of them. This makes it less likely that the tubular member 1 will be damaged when a guidewire, an intravascular treatment device, etc. is inserted.

[0053] The tubular member 1 preferably has a reinforcing layer 12. Specifically, the tubular member 1 preferably has the reinforcing layer 12 at least in the tubular portion 10. The reinforcing layer 12 can reinforce the tubular portion 10, making it difficult for a guide wire, for example, to penetrate through the tubular portion 10 when the guide wire is inserted into the lumen of the tubular portion 10.

[0054] The reinforcing layer 12 preferably includes a coil, a braided tube, or a combination thereof. Having the reinforcing layer 12 with a coil or a braided tube, or even with a coil and a braided tube, makes the tubular member 1 less likely to be crushed in the radial direction 1D while maintaining flexibility. On the other hand, not having the reinforcing layer 12 with a coil or a braided tube allows the length of the tubular member 1 in the radial direction 1D to be reduced. The braided tube preferably has a mesh structure in which multiple wires are woven so as to intersect with each other. Each wire may be a solid wire or a twisted wire.

[0055] The reinforcing layer 12 preferably includes a metal wire, a fiber, or a combination thereof as the wire material, and more preferably includes a metal wire. The metal wire preferably includes stainless steel, titanium, a nickel-titanium alloy, a nickel-chromium alloy, a cobalt-chromium alloy, a tungsten alloy, or a combination thereof, and more preferably includes stainless steel. The metal wire may include a radiopaque material as described below. The fiber preferably includes polyarylate fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, carbon fiber, or a combination thereof. The fiber may be a monofilament or a multifilament.

[0056] It is more preferable that the tubular member 1 has a reinforcing layer 12 in the tubular portion 10, but does not have a reinforcing layer 12 in the tapered portion 11. This makes the tapered portion 11 more easily bendable. Furthermore, it is preferable that the distal end 12b of the reinforcing layer 12 is located proximal to the distal end of the tubular portion 10, within 5 mm of the distal end of the tubular portion 10. This allows reinforcement up to the vicinity of the distal end of the tubular portion 10.

[0057] 10, the proximal end 12a of the reinforcing layer 12 is preferably located distal to the distal end S1b of the first tapered surface S1. This makes the first tapered surface S1 and its vicinity more easily bendable. It is more preferable that the proximal end 12a of the reinforcing layer 12 is located distal to the distal end 11b of the tapered portion 11. This makes the tapered portion 11 more easily bendable.

[0058] The reinforcing layer 12 is preferably disposed between the inner layer 10L and the outer layer 10M or within the outer layer 10M in the radial direction 1D of the tubular member 1. This makes it difficult for the reinforcing layer 12 to be exposed to the inner cavity of the tubular portion 10.

[0059] 3, the distal end 2b of the linear member 2 is preferably located distal to the proximal end 12a of the reinforcing layer 12. This makes it easier for the first cutting surface 2S1 of the linear member 2 to bend the tubular member 1 toward the inner side 1D2 in the radial direction 1D.

[0060] Although not shown, the distal end 2b of the linear member 2 may be located proximal to the proximal end 12a of the reinforcing layer 12. This allows the outer diameter of the tubular portion 10 to be reduced in the area where the reinforcing layer 12 is present. In this case, the distal end 2b of the linear member 2 may be located distal to the distal end S1b of the first tapered surface S1, or may be located proximal to the distal end S1b of the first tapered surface S1. The distal end 2b of the linear member 2 may be located distal to the distal end 11b of the tapered portion 11, or may be located proximal to the distal end 11b of the tapered portion 11.

[0061] As shown in FIG. 11 , the tubular member 1 may further include at least one radiopaque ring 13 disposed at the proximal end 12a, the distal end 12b, or both ends of the reinforcing layer 12 so that they are positioned inside. In FIG. 11 , the radiopaque ring 13 is disposed at the distal end 12b of the reinforcing layer 12, and can function as a marker for the vicinity of the distal end of the tubular portion 10 under X-ray fluoroscopy. Although not shown, if the radiopaque ring 13 is disposed at the proximal end 12a of the reinforcing layer 12, the radiopaque ring 13 can function as a marker for the vicinity of the distal end 11b of the tapered portion 11 under X-ray fluoroscopy. The radiopaque ring 13 is preferably disposed between the reinforcing layer 12 and the outer layer 10M in the radial direction 1D of the tubular member 1. This prevents the end of the reinforcing layer 12 from opening, making it easier to prevent the reinforcing layer 12 from being exposed on the outer surface of the tubular member 1.

[0062] The radiopaque ring 13 is a ring containing a radiopaque material, and is preferably made of a radiopaque material, such as lead, barium, iodine, tungsten, gold, platinum, iridium, platinum-iridium alloy, stainless steel, titanium, cobalt-chromium alloy, palladium, tantalum, or a combination thereof.

[0063] In the axial direction 10X of the tubular portion 10, the length from the proximal end of the tubular member 1 to the proximal end of the linear member 2 is preferably at least twice the length of the tubular member 1. This reduces friction when inserting the linear member 2 into the catheter 99. This magnification may be 10 times or less. The length of the extension catheter 91 is preferably 1000 mm or more and 2000 mm or less. The length of the tubular member 1 is preferably 150 mm or more and 500 mm or less. The outer diameter of the tubular member 1 is preferably 1.2 mm or more and 3 mm or less. The diameter of the lumen of the tubular member 1 is preferably 1.0 mm or more and 2.2 mm or less.

[0064] This application claims the benefit of priority based on Japanese Patent Application No. 2024-032460, filed on March 4, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-032460, filed on March 4, 2024, are incorporated herein by reference.

[0065] DESCRIPTION OF SYMBOLS 1 Cylindrical member 1C Central axis 1D Radial direction 1D1 Outer side 1D2 Inner side 1X Axial direction 2 Linear member 2b Distal end 2B Distal end portion 2P1 First portion 2P1a Proximal end 2P2 Second portion 2S1 First cutting surface 2S1a Proximal end 2S1b Distal end 2S2 Second cutting surface 2S2a Proximal end 2S3 Inward cutting surface 2S3b Distal end 2X Axial direction 3 Handle member 10 Cylindrical portion 10L Inner layer 10M Outer layer 10X Axial direction 11 Tapered portion 11a Proximal end 11b Distal end 11P Opening 12 Reinforcing layer 12a Proximal end 12b Distal end 13 Radiopaque ring 91 Extension catheter 99 Catheter 99Pa Proximal opening 99Pb Distal opening H1, H3 Radial length S1, S2, S3 First tapered surface, second tapered surface, third tapered surface S1a Proximal end S1b Distal end

Claims

1. An extension catheter that is inserted into a catheter and can protrude from a distal opening of the catheter, the extension catheter having a tubular member and a linear member whose distal end is fixed to the tubular member, the linear member having a first cutting surface on its side that faces radially outward from the tubular member.

2. The extension catheter of claim 1, wherein at least a portion of said first cutting surface is located at said distal end.

3. An extension catheter according to claim 1 or 2, wherein the linear member has a plurality of cutting surfaces on the side surface, and the first cutting surface is the cutting surface with the largest area between the distal end of the linear member and a position 20 cm away on the proximal side.

4. An extension catheter according to claim 1 or 2, wherein said linear member does not have a cutting surface facing inward in the radial direction at least in the portion fixed to said tubular member.

5. An extension catheter according to claim 1 or 2, wherein the first cutting surface is inclined with respect to the axial direction of the tubular member, and the distal end of the first cutting surface is located more inward than the proximal end in the radial direction.

6. An extension catheter according to claim 1 or 2, wherein said first cutting surface does not have a portion that is parallel to the axial direction of said tubular member.

7. The extension catheter of claim 3, wherein the proximal end of the most proximal cutting surface of said plurality of cutting surfaces is located proximally of the proximal end of said tubular member.

8. An extension catheter according to claim 1 or 2, wherein the linear member has a first portion including the first cutting surface and a second portion located proximal to the first portion and not having a cutting surface on its side, and in a cross section of the linear member in the radial direction of the tubular member, the first portion has a larger ratio of the major axis to the minor axis than the second portion.

9. The extension catheter of claim 8, wherein the proximal end of said first section is located proximal to the proximal end of said tubular member.

10. The extension catheter according to claim 8, wherein the length of said first portion is 10% or less of the length of said linear member.

11. The extension catheter of claim 8, wherein said first portion is located between the distal end of said tubular member and a position that is at least 20 cm and not more than 40 cm from said distal end of said tubular member.

12. The extension catheter according to claim 1 or 2, wherein said tubular member has a reinforcing layer.

13. The extension catheter according to claim 12, wherein the distal end of said linear member is located distal to the proximal end of said reinforcing layer.

14. The extension catheter according to claim 12, wherein the distal end of said linear member is located proximal to the proximal end of said reinforcing layer.

15. The extension catheter according to claim 1 or 2, wherein the tubular member has a tubular portion and a tapered portion located proximally of the tubular portion.

16. An extension catheter as described in claim 15, wherein the distal end of said first cutting surface is located at the distal end of said linear member, and the distal end of said tapered portion of said tubular member is located proximal to the distal end of said first cutting surface and distal to the proximal end of said first cutting surface.

17. The extension catheter according to claim 1 or 2, wherein the linear member is a solid linear member having no lumen.

18. The extension catheter according to claim 15, wherein the proximal end of the tapered surface of the tapered portion is closer to the linear member than the distal end of the tapered surface in the radial direction of the tubular member.

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