Extension catheter

Abstract

Provided is an extension catheter excellent in strength for fixing a linear member to a cylindrical member. The extension catheter according to the present invention is inserted into a catheter and can be protruded from an opening on a distal side of the catheter. The extension catheter comprises a cylindrical member and a linear member with a distal end portion thereof fixed to the cylindrical member. The cylindrical member comprises an inner layer containing a fluororesin and a proximal end portion located closer to a proximal side than a proximal end of the inner layer. The linear member is fixed to the cylindrical member at least inside the proximal end portion.

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] In conventional extension catheters such as those disclosed in Patent Document 1, the tubular member fixed to the distal end of the linear member can be moved by pushing or pulling back the linear member, but depending on the procedure, the linear member may be repeatedly pushed and pulled inside the body. The present invention was made in light of the above-mentioned circumstances, and its object is to provide an extension catheter that has excellent fixing strength for the linear member to the tubular member.

[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 portion fixed to the tubular member, the tubular member having an inner layer containing a fluororesin and a proximal end portion located proximal to the proximal end of the inner layer, and the linear member being fixed to the tubular member at least inside the proximal end portion.

[0006] The inventors' studies have revealed that the presence of fluororesin in a portion of a tubular member near a linear member may weaken the strength of fixation of the linear member to the tubular member. On the other hand, with the configuration of [1] above, the presence of fluororesin is reduced in a portion of the tubular member near the linear member at the proximal end of the tubular member located proximal to the inner layer containing fluororesin, thereby improving the strength of fixation of the linear member to the tubular member. An extension catheter according to an embodiment is preferably any one of [2] to

[18] below. [2] The extension catheter according to [1], wherein the linear member has a portion inside the proximal end that is not in contact with the fluororesin over the entire circumference. [3] The extension catheter according to [1] or [2], wherein the linear member is located in the far region of the region closer to the central axis of the tubular member and the far region in a cross section of the proximal end in the radial direction of the tubular member. [4] The extension catheter according to any one of [1] to [3], wherein, in a cross section of the proximal end portion in the radial direction of the tubular member, the proximal end portion has a portion extending in the radial direction of the tubular member. [5] The extension catheter according to any one of [1] to [4], wherein, in a cross section of the proximal end portion in the radial direction of the tubular member, the outer edge of the proximal end portion is elliptical, oval, egg-shaped, or a combination thereof. [6] The extension catheter according to any one of [1] to [5], wherein the tubular member has an outer layer located radially outward from the inner layer, and the proximal end of the outer layer is located at the proximal end portion of the tubular member, and the distal end of the outer layer is located distal to the proximal end of the inner layer. [7] The extension catheter according to any one of [1] to [6], wherein the tubular member has a first resin attached to the linear member, and the first resin extends at least from the proximal end portion to the distal end of the linear member. [8] The extension catheter according to any one of [1] to [7], wherein the linear member has a tapered portion. [9] The extension catheter according to [8], wherein a proximal end of the tapered portion of the linear member is located proximally relative to the proximal end of the tubular member, and a distal end of the tapered portion of the linear member is located distal to the proximal end of the inner layer.

[10] The extension catheter according to any one of [1] to [9], wherein the distal end of the linear member is located distally of the proximal end of the inner layer.

[11] The extension catheter according to any one of [1] to [6] and [8], wherein the distal end of the linear member is located proximally of the proximal end of the inner layer.

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

[11] , wherein the tubular member has a braided tube, and wherein the distal end of the linear member is located distally of the proximal end of the braided tube.

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

[11] , wherein the tubular member has a braided tube, and wherein the distal end of the linear member is located proximally of the proximal end of the braided tube.

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

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

[15] The extension catheter according to any one of [7] to

[10] and

[12] to

[14] , wherein the first resin is a thermoplastic resin.

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

[15] , wherein the tubular member further has: a braided tube; and at least one radiopaque ring arranged so that a proximal end, a distal end, or both ends of the braided tube are located inside.

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

[16] , wherein the linear member is a solid linear member without an internal cavity.

[18] The extension catheter according to any one of

[14] to

[17] , wherein, in the radial direction of the tubular member, 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.

[0007] According to the present invention, an extension catheter can be provided that has excellent fixing strength for fixing a linear member to a tubular member.

[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 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 proximal end portion of the tubular member of the extension catheter of FIG. 1. FIG. 5 is a IV-IV cross-sectional view of the proximal end portion of a modified tubular member of the extension catheter of FIG. 1. FIG. 6 is a VI-VI cross-sectional view of the tubular member of the extension catheter of FIG. 1. FIG. 7 is a VI-VI cross-sectional view showing an example of the tubular member of the extension catheter of FIG. 1 in which a fluororesin is present in the vicinity of the linear member. FIG. 8 is a side view of the extension catheter of FIG. 1 inserted into a curved guiding catheter. FIG. 9 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. FIG. 10 is a side view of a modified linear member of the extension catheter of FIG. 1. 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 having a distal end fixed to the tubular member, the tubular member having an inner layer containing a fluororesin and a proximal end located proximal to the proximal end of the inner layer, the linear member being fixed to the tubular member at least inside the proximal end. Research by the present inventors has revealed that the presence of fluororesin in a portion of the tubular member near the linear member may weaken the strength of fixation of the linear member to the tubular member. On the other hand, with the above configuration, the fluororesin is less likely to be present in a portion of the tubular member near the linear member at the proximal end of the tubular member located proximal to the inner layer containing fluororesin, thereby improving the strength of fixation of the linear member to the tubular member.

[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. FIG. 4 is a cross-sectional view taken along line IV-IV at the proximal end of the tubular member of the extension catheter of FIG. 1. FIG. 5 is a cross-sectional view taken along line IV-IV at the proximal end of a modified tubular member of the extension catheter of FIG. 1. FIG. 6 is a cross-sectional view taken along line VI-VI of the tubular member of the extension catheter of FIG. 1. FIG. 7 is a cross-sectional view taken along line VI-VI showing an example of the tubular member of the extension catheter of FIG. 1 in which a fluororesin is present near the linear member. FIG. 8 is a side view of the extension catheter of FIG. 1 inserted into a guiding catheter in a curved state. FIG. 9 is a side view of the tapered portion of the extension catheter of FIG. 1 and its vicinity. Figure 10 is a side view of a variation of the linear member of the extension catheter of Figure 1. Figure 11 is a side view of the extension catheter of Figure 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, the tubular member 1 has an inner layer 10L containing a fluororesin and a proximal end portion 1A located proximal to the proximal end 10La of the inner layer 10L. The linear member 2 is fixed to the tubular member 1 at least inside the proximal end portion 1A. At the proximal end portion 1A of the tubular member 1 located proximal to the inner layer 10L containing a fluororesin, the fluororesin is less likely to be present in the vicinity of the linear member 2, and therefore the fixing strength of the linear member 2 to the tubular member 1 can be improved.

[0015] The fluororesin contained in the inner layer 10L improves the chemical resistance, non-stickiness, low friction, etc. of the inner surface of the cylindrical member 1. The fluororesin preferably contains polytetrafluoroethylene, ethylene tetrafluoroethylene, fluorinated ethylene propylene, or a combination thereof.

[0016] It is preferable that the linear member 2 has a portion inside the proximal end 1A that is not in contact with the fluororesin over the entire circumference. In Figure 4, a first resin R1 that does not contain fluororesin is attached over the entire circumference of the linear member 2. This can improve the fixing strength of the linear member 2 at the proximal end 1A. It is preferable that the proximal end 1A does not contain fluororesin, but for example, a small amount of fluororesin that has eluted from portions other than the proximal end 1A may be present within the proximal end 1A.

[0017] 4, in a cross section of the proximal end portion 1A in the radial direction 1D of the tubular member 1, it is preferable that the linear member 2 is located in the far side region 1Af of the region 1An closer to the central axis 1C of the tubular member 1 and the far side region 1Af. This makes it difficult for the portion of the linear member 2 located within the proximal end portion 1A to be exposed from the region 1An closer to the central axis 1C when the linear member 2 is operated.

[0018] 4, in a cross section of the proximal end portion 1A in the radial direction 1D of the tubular member 1, the proximal end portion 1A preferably has a portion extending in the radial direction 1D of the tubular member 1. This makes it difficult for the portion of the linear member 2 located within the proximal end portion 1A to be exposed from the proximal end portion 1A when the linear member 2 is manipulated.

[0019] In a cross section of the proximal end portion 1A in the radial direction 1D of the tubular member 1, the outer edge of the proximal end portion 1A is preferably elliptical, oval, egg-shaped, or a combination thereof. The outer edge of the proximal end portion 1A in Fig. 4 has a shape that is a combination of two ellipses, but it may also have a shape of a single ellipse as shown in Fig. 5. An example of an elliptical shape is a shape in which a portion of a circle is extended, such as a shape in which a pair of opposing arcs spaced apart are connected by a pair of parallel lines.

[0020] 3 and 4, the cylindrical member 1 preferably has a first resin R1 attached to the linear member 2. The first resin R1 easily adheres to other resins, and therefore the fixing strength of the linear member 2 can be improved.

[0021] The first resin R1 is preferably a thermoplastic resin, and more preferably a thermoplastic elastomer. This makes it easier for the first resin R1 to adhere to the linear member 2 and other resins when heated during the manufacturing process. The first resin R1 preferably contains a polyamide resin, a polyurethane resin, a modified polyolefin resin, 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. It is preferable that the first resin R1 does not contain a fluororesin.

[0022] As shown in Fig. 3, the first resin R1 preferably extends at least from the proximal end portion 1A to the distal end 2b of the linear member 2. This improves the strength of fixation of the linear member 2 to the tubular member 1 via the first resin R1. The distal end of the first resin R1 is preferably located distal to the distal end 2b of the linear member 2. Furthermore, the distal end of the first resin R1 is preferably located proximal to a point 50 mm distal to the distal end 2b of the linear member 2 in the axial direction 1X of the tubular member 1. This allows the outer diameter of the tubular portion 10 to be reduced.

[0023] 3, the tubular member 1 preferably has an outer layer 10M located outside the inner layer 10L in the radial direction 1D. By having the outer layer 10M in the tubular member 1, for example, when a guide wire is inserted into the lumen of the tubular member 1, the guide wire is less likely to penetrate through the tubular member 1.

[0024] 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. The polyamide resin preferably contains nylon 12, a polyether block amide copolymer, or a combination thereof. The outer layer 10M preferably does not contain a fluororesin.

[0025] 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.

[0026] 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.

[0027] 1 and 3, the proximal end 10Ma of the outer layer 10M is preferably located at the proximal end 1A of the tubular member 1, and the distal end 10Mb of the outer layer 10M is preferably located distal to the proximal end 10La of the inner layer 10L. This allows the first resin R1 to be attached to the outer layer 10M from the proximal end 1A to the distal side of the proximal end 1A, thereby improving the fixing strength of the linear member 2 to the tubular member 1 via the first resin R1. The distal end 10Mb of the outer layer 10M is preferably located distal to the distal end 2b of the linear member 2. This allows the fixing strength of the linear member 2 to the tubular member 1 to be improved.

[0028] As shown in FIG. 3 , the tubular member 1 may have an intermediate layer 10N located outside the inner layer 10L and inside the outer layer 10M in the radial direction 1D. Alternatively, although not shown, the tubular member 1 may have an intermediate layer 10N located outside the inner layer 10L without having an outer layer 10M. The intermediate layer 10N 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. The polyamide resin preferably contains nylon 12, a polyether block amide copolymer, or a combination thereof. The intermediate layer 10N preferably does not contain a fluororesin. The intermediate layer 10N preferably contains a resin different from the resin contained in the outer layer 10M. If the intermediate layer 10N has an exposed portion on the outer surface, the intermediate layer 10N preferably contains a hydrophilic polymer on the exposed portion on the outer surface. For the hydrophilic polymer, please refer to the description of the hydrophilic polymer on the outer surface of the outer layer 10M described above.

[0029] As shown in Figure 3, the proximal end 10Na of the intermediate layer 10N is preferably located at the same position as the proximal end 10La of the inner layer 10L in the axial direction 1X of the tubular member 1, or is preferably located more proximal than the proximal end 10La of the inner layer 10L. Furthermore, as shown in Figures 1 and 3, the distal end 10Nb of the intermediate layer 10N is preferably located more distal than the proximal end 10La of the inner layer 10L. This makes it difficult for the fluororesin to be present in the portion of the tubular member 1 near the linear member 2. As shown in Figure 1, the distal end 10Mb of the outer layer 10M is preferably located more proximal than the distal end 10Nb of the intermediate layer 10N. This allows the outer diameter of the portion of the tubular member 1 distal to the outer layer 10M to be reduced.

[0030] As shown in Fig. 6 , in a portion distal to the proximal end portion 1A, it is preferable that the first resin R1 attached to the linear member 2 is not in contact with the inner layer 10L containing the fluororesin. This can improve the fixing strength of the linear member 2 to the tubular member 1 via the first resin R1. However, for example, when the linear member 2 to which the first resin R1 is attached is embedded in the intermediate layer 10N while being heated using a heat-shrinkable tube to fix the linear member 2 to the tubular member 1, a portion where the first resin R1 comes into contact with the inner layer 10L may be generated, as shown in Fig. 7 . In this contact portion, the fixing strength of the linear member 2 via the first resin R1 is weakened. However, since the fluororesin is unlikely to be present near the linear member 2 in the proximal end portion 1A of the extension catheter 91, the linear member 2 can be firmly fixed within the proximal end portion 1A.

[0031] 3, the distal end 2b of the linear member 2 is preferably located distal to the proximal end 10La of the inner layer 10L. This increases the length of the fixed portion of the linear member 2 to the tubular member 1, thereby improving the fixing strength of the linear member 2 to the tubular member 1.

[0032] Although not shown, the distal end 2b of the linear member 2 may be located proximal to the proximal end 10La of the inner layer 10L, thereby improving the flexibility of the tubular member 1.

[0033] 6, in the portion distal to the proximal end portion 1A, 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. Note that in the portion where the linear member 2 is fixed to the tubular member 1, a first resin R1 is preferably attached to the outer surface of the linear member 2.

[0034] The inner layer 10L, the intermediate layer 10N, and the outer layer 10M preferably extend in the axial direction 10X from the tubular portion 10 to the tapered portion 11, which will be described later. This facilitates smooth curvature in the order from the tubular portion 10 to the tapered portion 11.

[0035] As shown in FIG. 1 , 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. 8 , 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.

[0036] As shown in FIG. 9 , 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.

[0037] As shown in FIG. 9 , 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 between the second tapered surface S2 and 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 endovascular treatment device shaking when inserted into the opening 11P.

[0038] As shown in FIG. 9 , 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.

[0039] As shown in FIG. 9 , 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.

[0040] 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. 9, 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.

[0041] 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. 9, 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.

[0042] As shown in Fig. 9, in the radial direction 1D of the tubular member 1, the proximal end of the tapered surface 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 makes it easier to insert an intravascular treatment device through at least the 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.

[0043] 9 , 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 proximal end portion 1A of the tubular member 1 may have a portion that protrudes inward in the radial direction 1D of the tubular member 1. It is preferable that the protruding portion contains the first resin R1. This makes it even more difficult for the linear member 2 to detach from the tubular member 1 during operation of the linear member 2. Although not shown, in this field of view, the proximal end portion 1A of the tubular member 1 does not have to have a portion that protrudes inward in the radial direction 1D of the tubular member 1.

[0044] The tubular member 1 preferably does not have through holes, grooves, or the like 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 a coil in the tubular portion 10, the tapered portion 11, or both. Having the tubular member 1 with a coil or a braided tube 12 (described later), or even with a coil and a braided tube 12, makes the tubular member 1 less likely to collapse in the radial direction 1D while maintaining flexibility. On the other hand, not having the tubular member 1 with a coil or a braided tube 12 allows the length of the tubular member 1 in the radial direction 1D to be reduced.

[0045] The tubular member 1 preferably has a braided tube 12. Specifically, the tubular member 1 preferably has the 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. Furthermore, 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. Furthermore, the distal end 12b of the braided tube 12 is preferably 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.

[0046] 9, 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.

[0047] The braided tube 12 preferably has a mesh structure in which multiple wires are woven to cross 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.

[0048] The braided tube 12 is preferably disposed between the inner layer 10L and the intermediate layer 10N or within the intermediate layer 10N 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.

[0049] 3, the distal end 2b of the linear member 2 is preferably located distal to the proximal end 12a of the braided tube 12. This lengthens the portion of the linear member 2 fixed to the tubular member 1, thereby improving the strength of fixation of the linear member 2 to the tubular member 1. Furthermore, when the tubular member 1 is inserted into a curved portion inside the body, the braided tube 12 and the portion proximal to the braided tube 12 tend to bend more smoothly in that order.

[0050] 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.

[0051] As shown in Figure 3, the linear member 2 preferably has a tapered portion 2T. By having the tapered portion 2T in which the linear member 2 tapers toward the distal end 2b, it is possible to easily reduce the outer diameter of the tubular member 1 at and near the distal end 2b of the linear member 2. Furthermore, when inserted into a curved portion inside the body, this portion is more likely to curve smoothly. It is preferable that the tapered portion 2T include the distal end 2b of the linear member 2 or be adjacent to the distal end 2b.

[0052] As shown in FIG. 3 , the tapered portion 2T of the linear member 2 preferably has a tapered surface 2S. The tapered surface 2S preferably includes the distal end 2b of the linear member 2 or is adjacent to the distal end 2b. The angle between the tapered surface 2S and the axial direction 2X of the linear member 2 is preferably 1° or more and 45° or less, and more preferably 2° or more and 30° or less. As shown in FIG. 3 , the tapered surface 2S of the tapered portion 2T of the linear member 2 may face the outside in the radial direction 1D of the tubular member 1, or, although not shown, may face the inside in the radial direction 1D. The outside in the radial direction 1D of the tubular member 1 is the side farther from the central axis 1C of the tubular member 1 in the radial direction 1D, and the inside in the radial direction 1D of the tubular member 1 is the side closer to the central axis 1C of the tubular member 1 in the radial direction 1D. In addition, the tapered portion 2T of the linear member 2 may have a tapered surface facing outward in the radial direction 1D of the tubular member 1 and a tapered surface facing inward in the radial direction 1D of the tubular member 1.

[0053] As shown in FIG. 10 , the tapered portion 2T of the linear member 2 may have multiple tapered surfaces. In this case, the multiple tapered surfaces preferably include a distal tapered surface 2S1 located most distally among the multiple tapered surfaces and a proximal tapered surface 2S2 located more proximal than the distal tapered surface 2S1. The angles formed by the distal tapered surface 2S1 and the proximal tapered surface 2S2 with respect to the axial direction 2X of the linear member 2 are preferably 1° or more and 45° or less, and more preferably 2° or more and 30° or less. The angle formed by the distal tapered surface 2S1 with respect to the axial direction 2X of the linear member 2 may be larger or smaller than the angle formed by the proximal tapered surface 2S2 with respect to the axial direction 2X of the linear member 2. In the axial direction 2X, the distal tapered surface 2S1 may be longer or shorter than the proximal tapered surface 2S2.

[0054] 3, it is preferable that the proximal end 2Ta of the tapered portion 2T of the linear member 2 is located closer to the proximal side than the proximal end 1a of the tubular member 1. This improves the flexibility of the portion of the tubular member 1 where the linear member 2 is located.

[0055] Although not shown, it is preferable that the distal end 2Tb of the tapered portion 2T of the linear member 2 is located distal to the proximal end 10La of the inner layer 10L, thereby improving the flexibility of the portion of the tubular member 1 where the linear member 2 is located.

[0056] As shown in Figures 3 and 6, 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 tapered portion 2T that tapers toward the distal side.

[0057] 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.

[0058] As shown in FIG. 11 , the tubular member 1 may further include at least one radiopaque ring 13 positioned 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. 11 , the radiopaque ring 13 is positioned 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 positioned 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 positioned between the braided tube 12 and the intermediate layer 10N 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.

[0059] 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.

[0060] 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.

[0061] This application claims the benefit of priority based on Japanese Patent Application No. 2024-032457, filed on March 4, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-032457, filed on March 4, 2024, are incorporated herein by reference.

[0062] REFERENCE SIGNS LIST 1 Cylindrical member 1A Proximal end 1An Region closer to central axis 1Af Region farther from central axis 1C Central axis 1D Radial direction 1X Axial direction 2 Linear member 2b Distal end 2B Distal end 2T Tapered portion 2Ta Proximal end 2Tb Distal end 2S Tapered surface 2S1 Distal tapered surface 2S2 Proximal tapered surface 2X Axial direction 3 Handle member 10 Cylindrical portion 10L Inner layer 10La Proximal end 10N Intermediate layer 10Na Proximal end 10Nb Distal end 10M Outer layer 10Ma Proximal end 10Mb Distal end 10X Axial direction 11 Tapered portion 11a Proximal end 11b Distal end 11P Opening 12 Braided tube 12a: Proximal end 12b: Distal end 13: Radiopaque ring 91: Extension catheter 99: Catheter 99Pa: Proximal opening 99Pb: Distal opening R1: First resin 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 said catheter, comprising: a tubular member; and a linear member having a distal end fixed to said tubular member, said tubular member having an inner layer containing a fluororesin and a proximal end located proximal to the proximal end of said inner layer, said linear member being fixed to said tubular member at least inside said proximal end.

2. The extension catheter according to claim 1, wherein said linear member has a portion inside said proximal end that is not in contact with the fluororesin over the entire circumference.

3. An extension catheter according to claim 1 or 2, wherein, in a cross section of the proximal end portion in the radial direction of the tubular member, the linear member is located in the farther region of the region closer to the central axis of the tubular member and the farther region.

4. An extension catheter according to claim 1 or 2, wherein in a cross section of said proximal end portion in the radial direction of said tubular member, said proximal end portion has a portion extending in the radial direction of said tubular member.

5. The extension catheter according to claim 1 or 2, wherein in a cross section of said proximal end in the radial direction of said tubular member, the outer edge of said proximal end is elliptical, oval, egg-shaped, or a combination thereof.

6. An extension catheter according to claim 1 or 2, wherein the tubular member has an outer layer located radially outward of the inner layer, the proximal end of the outer layer being located at the proximal end of the tubular member, and the distal end of the outer layer being located distal to the proximal end of the inner layer.

7. An extension catheter as described in claim 1 or 2, wherein the tubular member has a first resin attached to the linear member, and the first resin extends at least from the proximal end to the distal end of the linear member.

8. The extension catheter according to claim 1 or 2, wherein said linear member has a tapered portion.

9. An extension catheter as described in claim 8, wherein the proximal end of the tapered portion of the linear member is located proximal to the proximal end of the tubular member, and the distal end of the tapered portion of the linear member is located distal to the proximal end of the inner layer.

10. An 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 inner layer.

11. 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 inner layer.

12. An extension catheter according to claim 1 or 2, wherein the tubular member has a braided tube, and the distal end of the linear member is located distal to the proximal end of the braided tube.

13. An extension catheter according to claim 1 or 2, wherein the tubular member has a braided tube, and the distal end of the linear member is located proximal to the proximal end of the braided tube.

14. 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.

15. The extension catheter of claim 7, wherein said first resin is a thermoplastic resin.

16. The extension catheter according to claim 1 or 2, wherein the tubular member further comprises: a braided tube; and at least one radiopaque ring disposed so that the proximal end, the distal end, or both ends of the braided tube are located inside the braided tube.

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 14, 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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