Extension catheter

Abstract

Provided is an extension catheter having a tubular portion thereof that is unlikely to be deformed into a distorted shape even when inserted into a curved portion inside a body. The extension catheter can be inserted into a catheter and protrude from a distal-side opening of the catheter, the extension catheter having a tubular member and a linear member having a distal end thereof fixed to the tubular member. The tubular member has a tubular portion and a tapered portion located more on the proximal-side than the tubular portion. The tubular member has a braided tube at least in the tubular portion. An opening-containing surface of the braided tube that includes a proximal-side opening is inclined. A proximal end of the opening-containing surface is closer to the linear member than a distal end of the opening-containing surface in the radial direction of the braided tube.

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 which comprises 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, the first tapered portion having an outer surface and a first tapered surface, the second tapered portion having an outer surface and a second tapered surface, the angle θ1 between the first tapered surface and the axial direction of the tubular portion being 90 to 145°, and the angle θ2 between the second tapered surface and the axial direction being 120 to 175°. Patent Document 1 also discloses that the tubular portion is provided with a braided reinforcing layer.

[0003] International Publication No. 2020 / 162286

[0004] The inventors have found through their investigations that, in conventional extension catheters having a braided reinforcing layer on the tubular portion, such as that disclosed in Patent Document 1, when the tubular portion is inserted into a curved portion such as an artery inside the body, the tubular portion may be deformed in a distorted shape near the proximal end of the reinforcing layer. The present invention has been made in light of the above-mentioned problems, and its object is to provide an extension catheter whose tubular portion is less likely to be deformed in a distorted shape even when inserted 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 can be inserted into a catheter and protrude from an opening on the distal side of the catheter, comprising: a tubular member; and a linear member having a distal end portion fixed to the tubular member, the tubular member having a tubular portion and a tapered portion located proximal to the tubular portion, the tubular member having a braided tube at least in the tubular portion, an opening-containing surface that includes an opening on the proximal side of the braided tube is inclined, and a proximal end of the opening-containing surface is closer to the linear member than a distal end of the opening-containing surface in the radial direction of the braided tube.

[0006] As described above, the braided tube has an opening-containing surface that is inclined in the radial direction so that the proximal end is closer to the linear member than the distal end, and when the tubular portion is inserted into a curved portion inside a body with the distal end of the opening-containing surface facing the inside of the curve, the tubular portion is less likely to deform into a distorted shape in the portion near the proximal end of the braided tube. An extension catheter according to an embodiment is preferably any one of the following [2] to

[12] . [2] The extension catheter according to [1], wherein the tapered portion has a first tapered surface and satisfies the following formulas (1) and (2): θ1≦45° ... (1) θ2<45° ... (2) [where θ1 represents the angle between the opening-containing surface of the braided tube and the first tapered surface, and θ2 represents the angle between the first tapered surface and the axial direction of the tubular portion. θ3>θ4 (3) [wherein θ3 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion. θ4 represents the angle between the first sloping portion and the axial direction of the tubular portion. ... [5] The extension catheter according to any one of [1] to [3], wherein the braided tube has a first wire, and the first wire has a first inclined portion that is inclined with respect to the axial direction of the tubular portion, and the extension catheter satisfies the following formula (4) in a field of view when the tubular member is oriented in a direction in which the tapered surface of the tapered portion is linear: θ3<θ4 ... (4) [where θ3 represents the angle formed between the opening-containing surface of the braided tube and the axial direction of the tubular portion. θ4 represents the angle formed between the first inclined portion and the axial direction of the tubular portion.[6] The extension catheter according to any one of [1] to [5], wherein the distal end of the linear member is located distally of the proximal end of the braided tube. [7] The extension catheter according to any one of [1] to [5], wherein the distal end of the linear member is located proximal to the proximal end of the braided tube. [8] The extension catheter according to any one of [2] to [7], wherein, in a field of view when the tubular member is oriented in a direction in which the first tapered surface is linear, the shortest distance from the distal end of the opening-containing surface of the braided tube to the first tapered surface is 0.5 times or more the length of the braided tube in the radial direction at the distal end of the opening-containing surface of the braided tube. [9] The extension catheter according to any one of [2] to [8], wherein the proximal end of the braided tube is located distally of the distal end of the first tapered surface.

[10] The extension catheter according to any one of [1] to [9], wherein the tubular member further has at least one radiopaque ring arranged so that the proximal end, the distal end, or both ends of the braided tube are located inside.

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

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

[12] The extension catheter according to any one of [2] to

[11] , wherein the proximal end of the first tapered surface is closer to the linear member than the distal end of the first tapered surface in the radial direction of the braided tube.

[0007] According to the present invention, it is possible to provide an extension catheter whose tubular portion is unlikely to be deformed into a distorted shape even when inserted into a curved portion inside the body.

[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 of the extension catheter protruding from the distal opening. FIG. 3 is a side view of the extension catheter of FIG. 1 inserted into a curved guiding catheter. FIG. 4 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 5 is a side view of a braided tube disposed within the tubular portion of the extension catheter of FIG. 1. FIG. 6 is a side view of a modified example of a braided tube disposed within the tubular portion of the extension catheter of FIG. 1. FIG. 7 is an axial cross-sectional view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 1. FIG. 9 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 has a tubular member and a linear member having a distal end fixed to the tubular member, the tubular member having a tubular portion and a tapered portion located proximal to the tubular portion, the tubular member having a braided tube in at least the tubular portion, an opening-containing surface including an opening on the proximal side of the braided tube is inclined, and the proximal end of the opening-containing surface is closer to the linear member in the radial direction of the braided tube than the distal end of the opening-containing surface. As described above, because the braided tube has an opening-containing surface that is inclined so that the proximal end is closer to the linear member than the distal end in the radial direction, when the tubular portion is inserted into a curved portion inside a body with the distal end of the opening-containing surface on the inside of the curve, the tubular portion is less likely to deform into a distorted shape in the portion near the proximal end of the braided tube.

[0011] 1 to 9, extension catheters according to embodiments will be described below. 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 a side view of the extension catheter of FIG. 1 inserted into a curved guiding catheter. FIG. 4 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 5 is a side view of a braided tube disposed within the tubular portion of the extension catheter of FIG. 1. FIG. 6 is a side view of a modified example of a braided tube disposed within the tubular portion of the extension catheter of FIG. 1. FIG. 7 is an axial cross-sectional view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 1. FIG. 9 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] As shown in FIG. 1 , the tubular member 1 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 inner cavity of the tubular member 1 and faces outward in 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 inner cavity 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. 3 , for example. When inserting the intravascular treatment device into the opening 11P, a treatment catheter such as a balloon catheter or a stent delivery catheter may be used.

[0015] As shown in FIG. 1 , the tubular member 1 has a braided tube 12 at least in the tubular portion 10. The braided tube 12 can reinforce the tubular portion 10, making it difficult for a guide wire, for example, to penetrate through the tubular portion 10 when inserted into the lumen of the tubular portion 10. It is more preferable that the tubular member 1 has the braided tube 12 in the tubular portion 10 but not in the tapered portion 11. This makes the tapered portion 11 more easily bendable. It is also preferable that the distal end 12b of the braided tube 12 be located proximal to the distal end of the tubular portion 10 and 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.

[0016] As shown in Figures 4 and 5, the opening-containing surface 12S, including the proximal opening 12Q of the braided tube 12, is inclined. Specifically, the opening-containing surface 12S is inclined with respect to the axial direction 10X of the tubular portion 10. As shown in Figure 4, in the radial direction 12D of the braided tube 12, the proximal end 12Sa of the opening-containing surface 12S is closer to the linear member 2 than the distal end 12Sb of the opening-containing surface 12S. This makes it difficult for the tubular portion 10 to deform in a distorted shape near the proximal end 12a of the braided tube 12 when the tubular portion 10 is inserted into a curved portion of the body with the distal end 12Sb of the opening-containing surface 12S facing the inside of the curve, as shown in Figure 3, for example. The proximal opening 12Q of the braided tube 12 is the portion surrounding the opening 12P facing the proximal side of the braided tube 12. The inclined opening-containing surface 12S can be formed, for example, using a laser cutter.

[0017] 4, the tapered portion 11 has a first tapered surface S1, and it is preferable that the extension catheter 91 satisfy the following formulas (1) and (2): θ1≦45° (1) θ2<45° (2) (where θ1 represents the angle between the opening-containing surface 12S of the braided tube 12 and the first tapered surface S1, and θ2 represents the angle between the first tapered surface S1 and the axial direction 10X of the tubular portion 10).

[0018] As shown in formula (1), when θ1 is 45° or less, the opening-containing surface 12S and the first tapered surface S1 become closer to being parallel, so that when the tubular portion 10 is bent, it is even less likely to deform into a distorted shape near the opening-containing surface 12S. θ1 is more preferably 40° or less. On the other hand, θ1 is preferably 10° or more, and more preferably 20° or more. This allows the opening-containing surface 12S and the first tapered surface S1 to be spaced apart, thereby improving the flexibility of the tapered portion 11.

[0019] As shown in formula (2), by setting θ2 to less than 45°, it is possible to increase the opening area of ​​at least the opening 11P located inside the first tapered surface S1. θ2 is more preferably 40° or less. On the other hand, θ2 is preferably 10° or more, and more preferably 15° or more. This makes it less likely for the intravascular treatment instrument to shake when being inserted into the opening 11P.

[0020] As described above, it is preferable that the extension catheter 91 satisfies the formulas (1) and (2), but it may also satisfy either formula (1) or formula (2).

[0021] As shown in FIG. 4 , the tapered portion 11 of the tubular member 1 preferably has multiple tapered surfaces. The multiple tapered surfaces of the tapered portion 11 preferably include a first tapered surface S1 and a second tapered surface S2 located distal to the first tapered surface S1. The second tapered surface S2 preferably includes the distal end 11b of the tapered portion 11, and the angle formed by the second tapered surface S2 with the axial direction 10X of the tubular portion 10 is preferably greater than the angle θ2 formed by the first tapered surface S1 and the axial direction 10X of the tubular portion 10. This reduces the thin-walled portion near the distal end 11b of the tapered portion 11, making it less likely that an intravascular treatment device will get caught near the distal end 11b of the tapered portion 11. The angle formed by the second tapered surface S2 with the axial direction 10X of the tubular portion 10 is preferably 45° or more and 89° or less, and more preferably 50° or more and 85° or less. The tapered portion 11 of the cylindrical member 1 may have only one tapered surface.

[0022] As shown in FIG. 4 , the tapered portion 11 preferably includes a first tapered surface S1, a second tapered surface S2 located distal to the first tapered surface S1, and a third tapered surface S3 located proximal to the first tapered surface S1. The angle between the third tapered surface S3 and the axial direction 10X of the tubular portion 10 is preferably smaller than the angle θ2 between the first tapered surface S1 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 first tapered surface S1 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.

[0023] As shown in FIG. 4 , in a field of view when 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 θ2 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.

[0024] The first tapered surface S1 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. 4, 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 first tapered surface S1 has the largest area. This makes it easier to obtain the effects of the above-mentioned formulas (1) and (2) related to the first tapered surface S1.

[0025] It is preferable that the first tapered surface S1 has the longest length in the radial direction 1D of the cylindrical member 1 among the multiple tapered surfaces. In Fig. 4, among the first tapered surface S1, the second tapered surface S2, and the third tapered surface S3, the first tapered surface S1 has the longest length in the radial direction 1D. This makes it easier to obtain the effects of the above-mentioned formulas (1) and (2) related to the first tapered surface S1.

[0026] 4 , in the radial direction 12D of the braided tube 12, 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 makes it easier to insert an intravascular treatment device through at least the opening 11P located inside the first tapered surface S1. Similarly, in the radial direction 12D of the braided tube 12, 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.

[0027] 5 , the braided tube 12 has a first wire 12W, and the first wire 12W preferably has a first inclined portion 12W1 that is inclined with respect to the axial direction 10X of the tubular portion 10. Such a braided tube 12 can reinforce the tubular portion 10, making it difficult for a guide wire, for example, to penetrate through the tubular portion 10 when inserted into the lumen of the tubular portion 10.

[0028] 4 and 5, in a field of view when the tubular member 1 is oriented so that the tapered surface of the tapered portion 11 of the tubular member 1 is linear, it is preferable that the extension catheter 91 satisfies the following formula (3). Note that in the radial direction 12D of the braided tube 12 in this field of view, the proximal side of the first inclined portion 12W1 is close to the linear member 2, and the distal side is far from the linear member 2. θ3 > θ4 (3) [In the formula, θ3 represents the angle between the opening-containing surface 12S of the braided tube 12 and the axial direction 10X of the tubular portion 10. θ4 represents the angle between the first inclined portion 12W1 and the axial direction 10X of the tubular portion 10.]

[0029] As shown in formula (3), when θ3 is greater than θ4, deformation of the opening-containing surface 12S during operation can be easily prevented. Specifically, the value of θ3 - θ4, i.e., the difference between θ3 and θ4, is preferably 1° or more, more preferably 5° or more. On the other hand, the difference between θ3 and θ4 is preferably 70° or less, more preferably 60° or less. This makes it easier for the opening-containing surface 12S and the portion of the braided tube 12 near it to bend.

[0030] 4 and 6, in a field of view when the tubular member 1 is oriented so that the tapered surface of the tapered portion 11 of the tubular member 1 is linear, it is preferable that the extension catheter 91 satisfies the following formula (4). Note that in the radial direction 12D of the braided tube 12 in this field of view, the proximal side of the first inclined portion 12W1 is close to the linear member 2, and the distal side is far from the linear member 2. θ3 < θ4 ... (4) [In the formula, θ3 represents the angle between the opening-containing surface 12S of the braided tube 12 and the axial direction 10X of the tubular portion 10. θ4 represents the angle between the first inclined portion 12W1 and the axial direction 10X of the tubular portion 10.]

[0031] As shown in formula (4), when θ3 is smaller than θ4, the opening-containing surface 12S and the portion thereof in the vicinity of the opening-containing surface 12S of the braided tube 12 are more likely to curve smoothly, making it easier to insert the tubular member 1 into curved portions of the body with particularly large curvatures. Specifically, the value of θ4 - θ3, i.e., the difference between θ4 and θ3, is preferably 1° or more, and more preferably 5° or more. Meanwhile, the difference between θ4 and θ3 is preferably 70° or less, and more preferably 60° or less. This makes it easier to prevent the braid on the opening-containing surface 12S from opening during operation.

[0032] In the field of view when the tubular member 1 is oriented so that the tapered surface of the tapered portion 11 of the tubular member 1 is linear, the angle θ3 between the opening-containing surface 12S of the braided tube 12 and the axial direction 10X of the tubular portion 10 is preferably 89° or less, more preferably 80° or less, and even more preferably 70° or less. This makes it easier for the opening-containing surface 12S and the portion of the braided tube 12 to bend. On the other hand, θ3 is preferably 20° or more, more preferably 30° or more. This makes it easier to prevent the braid of the opening-containing surface 12S from opening open during operation.

[0033] In the field of view when the tubular member 1 is oriented so that the tapered surface of the tapered portion 11 of the tubular member 1 is linear, the angle θ4 between the first inclined portion 12W1 and the axial direction 10X of the tubular member 10 is preferably 20° or more and 80° or less, and more preferably 30° or more and 70° or less. This allows the tubular portion 10 to be reinforced while maintaining the flexibility of the tubular portion 10 to a degree that allows it to bend along a curved portion inside the body.

[0034] As shown in Figures 5 and 6, the braided tube 12 preferably has a mesh structure in which multiple wires are woven to intersect with each other. Each wire may be a solid wire or a twisted wire. The braided tube 12 preferably includes metal wires, fibers, or a combination thereof, more preferably metal wires. The metal wires preferably include stainless steel, titanium, nickel-titanium alloys, nickel-chromium alloys, cobalt-chromium alloys, tungsten alloys, or a combination thereof, more preferably stainless steel. The metal wires may include a radiopaque material, as described below. The fibers preferably include polyarylate fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, PBO fibers, carbon fibers, or a combination thereof. The fibers may be monofilaments or multifilaments.

[0035] 4, the distal end 2b of the linear member 2 is preferably located distal to the proximal end 12a of the braided tube 12. This makes it easier for the tubular member 1 to bend smoothly in the order of the braided tube 12 and the portion proximal to the braided tube 12 when inserted into a curved portion inside the body. In this case, the distal end 2b of the linear member 2 may be located distal to the distal end 12Sb of the opening-containing surface 12S, or may be located proximal to the distal end 12Sb of the opening-containing surface 12S.

[0036] Although not shown, the distal end 2b of the linear member 2 may be located proximal to the proximal end 12a of the braided tube 12. This allows the outer diameter of the tubular portion 10 to be reduced in the area where the braided tube 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.

[0037] As shown in FIG. 4 , in the field of view when the tubular member 1 is oriented so that the first tapered surface S1 is linear, the shortest distance L1 from the distal end 12Sb of the opening-containing surface 12S of the braided tube 12 to the first tapered surface S1 is preferably at least 0.5 times the length L2 of the distal end 12Sb of the opening-containing surface 12S of the braided tube 12 in the radial direction 12D of the braided tube 12. This allows the flexible portion of the tubular portion 10 proximal to the opening-containing surface 12S to be elongated. The ratio is more preferably 0.8 times or more, and even more preferably 0.9 times or more. On the other hand, the ratio is preferably 3.0 times or less, more preferably 2.0 times or less, and even more preferably 1.5 times or less. This makes it easier to prevent deformation during bending due to excessive length of the flexible portion of the tubular portion 10 proximal to the opening-containing surface 12S.

[0038] As shown in Figure 4, the proximal end 12a of the braided tube 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 braided tube 12 is located distal to the distal end 11b of the tapered portion 11. This makes the tapered portion 11 more easily bendable.

[0039] 7, 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] The braided tube 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 braided tube 12 to be exposed to the lumen of the tubular portion 10.

[0045] 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.

[0046] 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.

[0047] The tubular member 1 preferably does not have through holes, grooves, etc. penetrating the outer and inner surfaces of the tubular portion 10, the tapered portion 11, or both. This makes it less likely that an intravascular treatment device will get caught inside the tubular member 1 during delivery. The tubular member 1 also preferably does not have non-penetrating grooves on the outer surfaces of the tubular portion 10, the tapered portion 11, or both. This makes it less likely that the tubular member 1 will be damaged during insertion of a guidewire, an intravascular treatment device, or the like. The tubular member 1 may also have coils in the tubular portion 10, the tapered portion 11, or both. By including the braided tube 12 and the coil, the tubular member 1 is less likely to be crushed in the radial direction 1D while maintaining flexibility. On the other hand, by not including a coil in the tubular member 1, the length of the tubular member 1 in the radial direction 1D can be reduced.

[0048] As shown in FIG. 8 , the linear member 2 is preferably a solid linear member without an internal cavity. This allows the thickness of the linear member 2 to be reduced. The linear member 2 may be made of any material that can push the tubular portion 10 distally. While the material is not particularly limited, it preferably includes stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, tungsten alloy, or a combination thereof, and more preferably includes stainless steel. The cross-sectional shape of the linear member 2 in the thickness direction is preferably square, rectangular, trapezoidal, circular, D-shaped, or elliptical, and more preferably rectangular. The cross-sectional shape of the linear member 2 in the thickness direction may vary in shape or size depending on the axial position. For example, the linear member 2 may have a portion that tapers toward the distal side.

[0049] 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.

[0050] As shown in FIG. 9 , 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 braided tube 12 so that they are positioned inside. In FIG. 9 , the radiopaque ring 13 is disposed at the distal end 12b of the braided tube 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 braided tube 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 braided tube 12 and the outer layer 10M in the radial direction 1D of the tubular member 1. This prevents the end of the braided tube 12 from opening, making it easier to prevent the braided tube 12 from being exposed on the outer surface of the tubular member 1.

[0051] 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.

[0052] 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.

[0053] This application claims the benefit of priority based on Japanese Patent Application No. 2024-032455, filed on March 4, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-032455, filed on March 4, 2024, are incorporated herein by reference.

[0054] DESCRIPTION OF SYMBOLS 1 Cylindrical member 1D Radial direction 2 Wire member 2b Distal end 2B Distal end portion 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 Braided tube 12a Proximal end 12b Distal end 12D Radial direction 12P Opening 12Q Opening 12S Opening-containing surface 12Sa Proximal end 12Sb Distal end 12W First wire rod 12W1 First inclined portion 13 Radiopaque ring 91 Extension catheter 99 Catheter 99Pa Proximal opening 99Pb Distal opening 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, comprising: a tubular member; and a linear member whose distal end is fixed to the tubular member, wherein the tubular member has a tubular portion and a tapered portion located proximal to the tubular portion, wherein the tubular member has a braided tube at least in the tubular portion, and an opening-containing surface including an opening on the proximal side of the braided tube is inclined, and in the radial direction of the braided tube, the proximal end of the opening-containing surface is closer to the linear member than the distal end of the opening-containing surface.

2. The extension catheter according to claim 1, wherein the tapered portion has a first tapered surface and satisfies the following formulas (1) and (2): θ1≦45° ... (1) θ2<45° ... (2) [where θ1 represents the angle between the opening-containing surface of the braided tube and the first tapered surface, and θ2 represents the angle between the first tapered surface and the axial direction of the tubular portion.] 3. An extension catheter according to claim 2, wherein the tapered portion has a plurality of tapered surfaces, and the first tapered surface is the tapered surface with the largest area among the plurality of tapered surfaces that are inclined at an angle of more than 5° and not more than 89° with respect to the axial direction of the tubular portion.

4. The extension catheter according to claim 1 or 2, wherein the braided tube has a first wire, and the first wire has a first inclined portion that is inclined with respect to the axial direction of the tubular portion, and the following formula (3) is satisfied in the field of view when the tubular member is oriented in a direction in which the tapered surface of the tapered portion is linear: θ3 > θ4 ... (3) [where θ3 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion, and θ4 represents the angle between the first inclined portion and the axial direction of the tubular portion.] 5. The extension catheter according to claim 1 or 2, wherein the braided tube has a first wire, and the first wire has a first inclined portion that is inclined with respect to the axial direction of the tubular portion, and the following formula (4) is satisfied in the field of view when the tubular member is oriented in a direction in which the tapered surface of the tapered portion is linear: θ3 < θ4 ... (4) [where θ3 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion, and θ4 represents the angle between the first inclined portion and the axial direction of the tubular portion.] 6. The extension catheter according to claim 1 or 2, wherein the distal end of said linear member is located distal to the proximal end of said braided tube.

7. The extension catheter according to claim 1 or 2, wherein the distal end of the linear member is located proximal to the proximal end of the braided tube.

8. An extension catheter as described in claim 2, wherein, in a field of view when the tubular member is oriented so that the first tapered surface is linear, the shortest distance from the distal end of the opening-containing surface of the braided tube to the first tapered surface is 0.5 times or more the radial length of the braided tube at the distal end of the opening-containing surface of the braided tube.

9. The extension catheter of claim 2, wherein the proximal end of said braided tube is located distal to the distal end of said first tapered surface.

10. The extension catheter of claim 1 or 2, wherein the tubular member further comprises at least one radiopaque ring disposed within the proximal end, the distal end, or both ends of the braided tube.

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

12. The extension catheter according to claim 2, wherein the proximal end of said first tapered surface is closer to said linear member in the radial direction of said braided tube than the distal end of said first tapered surface.

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