Extension catheter

Abstract

To provide an extension catheter that allows smooth insertion into a curved portion within the body.SOLUTION: This extension catheter is configured to be inserted into a catheter and protrudable from an opening on a distal side of the catheter. The extension comprises a cylindrical member and a linear member with a distal end fixed to the cylindrical member. The cylindrical member comprises a cylindrical part and a tapered part located on the proximal side relative to the cylindrical part. The cylindrical member comprises a braided tube at least in the cylindrical part. An opening-containing surface including an opening at the proximal side of the braided tube is inclined. In the radial direction of the braided tube, a distal end of the opening-containing surface is closer to the linear member than a proximal end of the opening-containing surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[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 the proximal opening of the guiding catheter, with a portion of the extension catheter protruding from the distal opening and inserted into the coronary artery. The use of such an extension catheter makes it easier to deliver intravascular treatment devices 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, 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 wherein 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°. Patent Document 1 also discloses that the tubular portion comprises a braided reinforcing layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 162286 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have found through their investigations that with conventional extension catheters having a braided reinforcing layer on the tubular portion, such as that disclosed in Patent Document 1, it is sometimes difficult to insert the tubular portion into curved portions such as arteries inside the body. The present invention has been made in light of the above-mentioned problems, and its purpose is to provide an extension catheter that is easy to insert into curved portions inside the body. [Means for solving the problem]

[0005] The extension catheter according to the embodiment that can solve the above problems is as follows. [1] An extension catheter that can be inserted into a catheter and protrude from a distal opening of the catheter, A cylindrical member; a linear member having a distal end fixed to the tubular member; the tubular member has a tubular portion and a tapered portion located proximal to 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 the proximal opening is inclined; An extension catheter in which, in the radial direction of the braided tube, the distal end of the opening-containing surface is closer to the linear member than the proximal end of the opening-containing surface.

[0006] As described above, by inclining the opening-containing surface of the braided tube so that the distal end is closer to the linear member than the proximal end in the radial direction, a trapezoidal portion is more likely to be formed between the opening-containing surface and the tapered surface of the tapered portion in a side view of the tubular member. As a result, when the tubular member is inserted into a curved portion inside the body with the proximal end of the opening-containing surface oriented toward the inside of the curve, it is more likely to curve along the curved portion inside the body, making it easier to insert the extension catheter into the curved portion inside the body. The extension catheter according to the embodiment is preferably any 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 formula (1): θ1≧70° (1) [wherein θ1 represents the angle between the opening-containing surface of the braided tube and the first tapered surface.] [3] The extension catheter according to [2], wherein the tapered portion has a plurality of tapered surfaces, and the first tapered surface is the tapered surface located most distally among the plurality of tapered surfaces. [4] The braided tube has a first wire, and the first wire has a first inclined portion inclined with respect to the axial direction of the tubular portion, The extension catheter according to any one of [1] to [3], which satisfies the following formula (2) in the field of view when the tubular member is oriented so that the tapered surface of the tapered portion is linear. θ2>θ3 (2) [In the formula, θ2 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion, and θ3 represents the angle between the first inclined portion and the axial direction of the tubular portion.] [5] The braided tube has a first wire, and the first wire has a first inclined portion inclined with respect to the axial direction of the tubular portion, The extension catheter according to any one of [1] to [3], which satisfies the following formula (3) in the field of view when the tubular member is oriented so that the tapered surface of the tapered portion is linear. θ2<θ3 (3) [In the formula, θ2 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion, and θ3 represents the angle 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 distal to 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 distal to 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 of these 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 that does not have an internal cavity.

[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. [Effects of the Invention]

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

[0008] [Figure 1] FIG. 1 is a side view of an extension catheter according to an embodiment. [Figure 2] FIG. 2 is a side view of the extension catheter of FIG. 1 inserted into the guiding catheter with a portion of the extension catheter protruding from the distal opening. [Figure 3] FIG. 3 is a side view of the extension catheter of FIG. 1 inserted into the guiding catheter in a curved state. [Figure 4] FIG. 4 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. [Figure 5]5 is a side view of a braided tube disposed within the tubular portion of the extension catheter of FIG. 1. FIG. [Figure 6] FIG. 6 is a side view of a variation of a braided tube disposed within the tubular portion of the extension catheter of FIG. [Figure 7] 7 is an axial cross-sectional view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. [Figure 8] FIG. 8 is a cross-sectional view taken along the line AA in FIG. [Figure 9] FIG. 9 is a side view of the extension catheter of FIG. 1 having a radiopaque ring. DETAILED DESCRIPTION OF THE INVENTION

[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. For convenience, component reference numerals may be omitted in the drawings. In such cases, reference should be made to the specification or other drawings. 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 can be inserted into a catheter and protrude from an opening on the distal side of the catheter, the extension catheter comprising 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 comprising a braided tube at least in the tubular portion, an opening-containing surface including an opening on the proximal side of the braided tube being inclined, and the distal end of the opening-containing surface being closer to the linear member in the radial direction of the braided tube than the proximal end of the opening-containing surface. As described above, by inclining the opening-containing surface of the braided tube so that the distal end is closer to the linear member than the proximal end in the radial direction, a trapezoidal portion is more likely to be formed between the opening-containing surface and the tapered surface of the tapered portion in a side view of the tubular member. As a result, when the tubular member is inserted into a curved portion inside a body with the proximal end of the opening-containing surface oriented toward the inside of the curve, the tubular member is more likely to bend along the curved portion inside the body, making it easier to insert the extension catheter into the curved portion inside the body.

[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 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 AA 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 ducts.

[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 lumen 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 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 the body and curved, 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 opening 12Q on the proximal side 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 distal end 12Sb of the opening-containing surface 12S is closer to the linear member 2 than the proximal end 12Sa of the opening-containing surface 12S. This facilitates the formation of a trapezoidal portion between the opening-containing surface 12S and the tapered surface of the tapered portion 11. As a result, for example, as shown in Figure 3, when the tubular portion 10 is inserted into a curved portion inside the body with the proximal end 12Sa of the opening-containing surface 12S facing the inside of the curve, the tubular member 11 is more likely to curve along the curved portion inside the body. The opening 12Q on the proximal side of the braided tube 12 is the portion surrounding the opening 12P facing the proximal side of the braided tube 12. The sloping opening-containing surface 12S can be formed, for example, by a laser cutter.

[0017] As shown in FIG. 4, the tapered portion 11 has a first tapered surface S1, and it is preferable that the extension catheter 91 satisfies the following formula (1). θ1≧70° (1) [In the formula, θ1 represents the angle between the opening-containing surface 12S of the braided tube 12 and the first tapered surface S1.]

[0018] When θ1 is 70° or more as shown in formula (1), the portion of the tubular portion 10 between the opening-containing surface 12S and the first tapered surface S1 has a shape close to a trapezoid as shown in FIG. 4, which makes it easier for the tubular portion 10 to bend smoothly when inserted into a curved portion inside the body as shown in FIG. 3. θ1 is more preferably 75° or more. On the other hand, θ1 is preferably 120° or less, and more preferably 90° or less. This makes it difficult for a guidewire, for example, to break through the tubular portion 10 when inserted into the lumen of the tubular portion 10 in a curved state.

[0019] As shown in FIG. 4, the tapered portion 11 of the tubular member 1 preferably has multiple tapered surfaces. The first tapered surface S1 is preferably the tapered surface located most distally among the multiple tapered surfaces. This makes it easier to achieve the effect of the above formula (1). The angle between the first tapered surface S1 and the axial direction 10X of the tubular portion 10 is preferably 20° or more, more preferably 30° or more. This reduces the thin-walled portion near the distal end 11b of the tapered portion 11, making it less likely that the intravascular treatment device will get caught near the distal end 11b of the tapered portion 11. On the other hand, this angle 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. The tapered portion 11 of the tubular member 1 may have only one tapered surface.

[0020] The 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 between the second tapered surface S2 and the axial direction 10X of the tubular portion 10 is preferably smaller than the angle between the first tapered surface S1 and the axial direction 10X of the tubular portion 10. This allows the opening area of ​​the opening 11P to be increased. 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 the opening area of ​​the opening 11P to be increased. Meanwhile, the 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.

[0021] As shown in FIG. 4, 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 tapered surface 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 cutting off a portion of the proximal end of the tubular body.

[0022] As shown in FIG. 4 , 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 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.

[0023] 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. 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 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.

[0024] 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. 4, 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.

[0025] 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. By slanting the first tapered surface S1 in this manner, it becomes easier to insert an intravascular treatment device through at least an 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.

[0026] 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.

[0027] 4 and 5, 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, it is preferable that the extension catheter 91 satisfies the following formula (2). Note that in the radial direction 12D of the braided tube 12 in this field of view, the distal side of the first inclined portion 12W1 is close to the linear member 2, and the proximal side is far from the linear member 2. θ2>θ3 (2) [In the formula, θ2 represents the angle between the opening-containing surface 12S of the braided tube 12 and the axial direction 10X of the tubular portion 10. θ3 represents the angle between the first inclined portion 12W1 and the axial direction 10X of the tubular portion 10.]

[0028] As shown in formula (2), when θ2 is greater than θ3, the opening-containing surface 12S and its neighboring portions of the braided tube 12 are more likely to bend smoothly, making it easier to insert the tubular member 1 into curved portions of the body with particularly large curvatures. Specifically, the value of θ2 - θ3, i.e., the difference between θ2 and θ3, is preferably 1° or more, more preferably 5° or more. On the other hand, the difference between θ2 and θ3 is preferably 60° or less, more preferably 50° or less. This makes it easier to prevent deformation of the opening-containing surface 12S during operation.

[0029] 4 and 6, 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, 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 distal side of the first inclined portion 12W1 is close to the linear member 2, and the proximal side is far from the linear member 2. θ2<θ3 (3) [In the formula, θ2 represents the angle between the opening-containing surface 12S of the braided tube 12 and the axial direction 10X of the tubular portion 10. θ3 represents the angle between the first inclined portion 12W1 and the axial direction 10X of the tubular portion 10.]

[0030] As shown in formula (3), by making θ2 smaller than θ3, it is possible to easily prevent the braid of the opening-containing surface 12S from opening during operation. Specifically, the value of θ3 - θ2, i.e., the difference between θ3 and θ2, is preferably 1° or more, and more preferably 5° or more. On the other hand, the difference between θ3 and θ2 is preferably 80° or less, and more preferably 70° or less. This makes it easier for the opening-containing surface 12S and the nearby portion of the braided tube 12 to bend.

[0031] 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 θ2 between the opening-containing surface 12S of the braided tube 12 and the axial direction 10X of the tubular portion 10 is preferably 91° or greater, more preferably 95° or greater, and even more preferably 100° or greater. This makes it easier for the opening-containing surface 12S and the surrounding area of ​​the braided tube 12 to bend. On the other hand, θ2 is preferably 160° or less, more preferably 150° or less. This makes it easier to prevent deformation of the opening-containing surface 12S 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 formed between the first inclined portion 12W1 and the axial direction 10X of the tubular member 10 is preferably 100° or more and 170° or less, and more preferably 110° or more and 160° 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.

[0033] As shown in Figures 5 and 6, the braided tube 12 preferably has a mesh structure in which multiple wires are woven so that they intersect with each other. Each wire may be a single wire or a twisted wire. The braided tube 12 preferably includes metal wires, fibers, or a combination thereof, more preferably metal wires, as the 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.

[0034] 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 the tubular member 1 is 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.

[0035] 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.

[0036] 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 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 of the braided tube 12 in the radial direction 12D at the distal end 12Sb of the opening-containing surface 12S 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.

[0037] 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.

[0038] 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.

[0039] The inner layer 10L preferably contains a fluororesin, and more preferably is made of a fluororesin. Fluororesin has excellent chemical resistance, non-stick properties, and low friction. The fluororesin preferably contains polytetrafluoroethylene, ethylene tetrafluoroethylene, fluorinated ethylene propylene, or a combination thereof.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 applied to the outer surface of the linear member 2.

[0045] It is preferable that the inner layer 10L and the outer layer 10M extend in the axial direction 10X from the cylindrical portion 10 to the tapered portion 11. This makes it easier to curve smoothly from the cylindrical portion 10 to the tapered portion 11.

[0046] 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, as long as it 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 be different 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.

[0047] As shown in FIG. 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.

[0048] 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 the proximal end 12a, the distal end 12b, or both ends. 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.

[0049] 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.

[0050] 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. [Explanation of symbols]

[0051] 1. Cylindrical member 1D radial 2 Linear members 2b distal end 2B Distal end 3 Handle parts 10 Cylindrical part 10L inner layer 10M outer layer 10X axial 11 Tapered section 11a proximal end 11b distal end 11P opening 12 Braided Tube 12a proximal end 12b distal end 12D radial 12P opening 12Q opening 12S Surface containing openings 12Sa proximal end 12Sb distal end 12W 1st wire 12W1 1st slope part 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 inserted into a catheter and capable of protruding from a distal opening of the catheter, A cylindrical member; a linear member having a distal end fixed to the tubular member; the tubular member has a tubular portion and a tapered portion located proximal to 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 the proximal opening is inclined; An extension catheter in which, in the radial direction of the braided tube, the distal end of the opening-containing surface is closer to the linear member than the proximal end of the opening-containing surface.

2. 2. The extension catheter according to claim 1, wherein the tapered portion has a first tapered surface and satisfies the following formula (1): θ1≧70° (1) [In the formula, θ1 represents the angle between the opening-containing surface of the braided tube and the first tapered surface.]

3. 3. The 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 located most distally among the plurality of tapered surfaces.

4. the braided tube has a first wire rod, and the first wire rod has a first inclined portion inclined with respect to an axial direction of the tubular portion, 3. The extension catheter according to claim 1, wherein the following formula (2) is satisfied in a field of view when the tubular member is oriented so that the tapered surface of the tapered portion is linear: θ2>θ3...(2) [In the formula, θ2 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion, and θ3 represents the angle between the first inclined portion and the axial direction of the tubular portion.]

5. the braided tube has a first wire rod, and the first wire rod has a first inclined portion inclined with respect to an axial direction of the tubular portion, 3. The extension catheter according to claim 1, wherein the following formula (3) is satisfied in a field of view when the tubular member is oriented so that the tapered surface of the tapered portion is linear: θ2<θ3...(3) [In the formula, θ2 represents the angle between the opening-containing surface of the braided tube and the axial direction of the tubular portion, and θ3 represents the angle between the first inclined portion and the axial direction of the tubular portion.]

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

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

8. 3. The extension catheter according to claim 2, wherein, in a field of view when the tubular member is oriented in a direction such 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 length of the braided tube in the radial direction at the distal end of the opening-containing surface of the braided tube.

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

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

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

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

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