Extension catheter and method for manufacturing extension catheter

Abstract

Provided is an extension catheter easy to insert into a tube inside a body. This extension catheter is inserted into a catheter and can protrude from a distal-side opening of the catheter. The extension catheter comprises a tubular member and a linear member having a distal end portion fixed to the tubular member. The tubular member includes a first resin having a portion located outside of the linear member in the radial direction and a second resin having a lower Shore D hardness than the first resin. A cross section of the tubular member in the radial direction has three regions obtained by equally dividing the tubular member in a direction passing through the centroid of the linear member and the centroid of the lumen of the tubular member, and designated as a first region, a second region, and a third region in order of increasing distance from the linear member. The first resin is positioned in the first region or in the first region and the second region, and the second resin is positioned at least in the third region. The first resin has a first exposed surface exposed on the outer surface of the tubular member.

Description

Extension catheter and method for manufacturing extension catheter

[0001] The present invention relates to an extension catheter and a method for manufacturing an extension catheter.

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

[0003] International Publication No. 2020 / 162286

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

[0005] Extension catheters according to embodiments that can solve the above problems are as follows: [1] An extension catheter that can be inserted into a catheter and protrude from an opening on the distal side of the catheter, comprising: a tubular member; and a linear member having a distal end fixed to the tubular member, wherein the tubular member comprises a first resin having a portion located radially outward from the linear member, and a second resin having a Shore D hardness lower than that of the first resin, wherein in a radial cross section of the tubular member, when the tubular member is divided into thirds in a direction passing through the centroid of the linear member and the centroid of the lumen of the tubular member and the third regions are defined in order of proximity to the linear member, the first resin is located in the first region or the first region and the second region, and the second resin is located in at least the third region, and the first resin has a first exposed surface that is exposed on the outer surface of the tubular member.

[0006]

[0004] Through research by the present inventors, it has been found that arranging a high-hardness resin in a portion of the tubular member close to the linear member so that a portion of the resin is exposed improves the hardness of the portion near the linear member and makes the outer surface of the tubular member less likely to twist, thereby improving the transmission of pushing force from the linear member to the tubular member. Furthermore, it has been found that arranging a low-hardness resin in a portion of the tubular member radially distant from the linear member makes the distant portion more likely to deform to conform to the shape of the vessel within the body when the tubular member is pushed into a vessel such as an artery within the body. Furthermore, the tubular member of the extension catheter described above in [1] has a first region, or the first and second regions, that can improve the transmission of pushing force from the linear member to the tubular member, and a third region that allows the tubular member to easily deform to conform to the shape of the vessel within the body, thereby making it easier to insert the tubular member into a vessel within the body due to the combined effects of these.

[0007] The extension catheter according to the embodiment or the method for manufacturing the extension catheter according to the embodiment is preferably any one of the following [2] to

[20] . [2] The extension catheter according to [1], wherein, in a cross section in the radial direction of the tubular member, a straight line passing through the centroid of the linear member and the centroid of the lumen of the tubular member intersects the first resin. [3] The extension catheter according to [1] or [2], wherein, in the radial direction of the tubular member, the first resin has a portion located more inward than the linear member. [4] The extension catheter according to any one of [1] to [3], wherein, at the distal end portion of the linear member, the first resin surrounds the periphery of the linear member. [5] The extension catheter according to any one of [1] to [4], wherein the tubular member includes a third resin having a Shore D hardness higher than that of the second resin, at a position closer to the linear member than the first resin. [6] The extension catheter according to [1], [2], or [5], wherein the first resin does not have a portion located inside the linear member in the radial direction of the tubular member. [7] The extension catheter according to any one of [1] to [6], wherein the first exposed surface extends in the axial direction of the tubular member. [8] The extension catheter according to any one of [1] to [7], wherein, in a cross section in the radial direction of the tubular member, the circumferential length of the first exposed surface is longer than the radial length of the first resin. [9] The extension catheter according to any one of [1] to [8], wherein the tubular member has an inner layer and an outer layer, and the outer layer contains the second resin.

[10] The extension catheter according to any one of [1] to [9], wherein the second resin has a lower melting point than the first resin.

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

[10] , wherein a distal end of the first resin is located distal to the distal end of the linear member, and a proximal end of the first resin is located proximal to the distal end of the linear member.

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

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

[13] The extension catheter according to

[12] , wherein the distal end of the first resin is located distal to the distal end of the tapered section, and the proximal end of the first resin is located proximal to the distal end of the tapered section.

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

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

[15] The extension catheter according to

[14] , wherein the distal end of the linear member is located distal to the proximal end of the reinforcing layer or proximal to the proximal end of the reinforcing layer.

[16] The extension catheter according to

[14] or

[15] , wherein the reinforcing layer has at least one radiopaque ring that is arranged so that the proximal end, the distal end, or both ends thereof are located inside.

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

[16] , wherein the linear member is a solid linear member that does not have an internal lumen.

[18] A method for manufacturing an extension catheter, comprising: a step of covering a distal end portion of a linear member with a first resin, a step of arranging the distal end portion of the linear member on the outer surface of a tubular member containing a second resin having a lower Shore D hardness than the first resin, a step of surrounding at least the distal end portion of the linear member and the tubular member with a fixing heat shrink tube, and a step of heating to shrink the fixing heat shrink tube, and fixing the distal end portion of the linear member to the tubular member so that a portion of the first resin is exposed from the outer surface of the tubular member.

[19] A method for manufacturing an extension catheter according to

[18] , further comprising, after the covering step but before the arranging step, a step of surrounding at least the first resin with a molding heat shrink tube, heating, and shrinking the molding heat shrink tube, thereby molding the first resin.

[20] A method for manufacturing an extension catheter according to

[18] or

[19] , further comprising, before the arranging step, a step of forming a groove on the outer surface of the tubular member.

[0008] According to the present invention, an extension catheter that can be easily inserted into a vessel in the body can be provided.

[0009] FIG. 1 is a side view of an extension catheter according to an embodiment. FIG. 2 is a side view of the extension catheter of FIG. 1 inserted into a guiding catheter with a portion protruding from the distal opening. FIG. 3 is a cross-sectional view of the tubular member of FIG. 1 taken along III-III. FIG. 4 is a cross-sectional view of a modified example of the tubular member of FIG. 1 taken along III-III. FIG. 5 is a cross-sectional view of a modified example of the tubular member of FIG. 1 taken along III-III. FIG. 6 is a cross-sectional view of a modified example of the tubular member of FIG. 1 taken along III-III. FIG. 7 is a cross-sectional view of a modified example of the tubular member of FIG. 1 taken along III-III. FIG. 8 is a cross-sectional view of the tapered portion of the extension catheter of FIG. 1 and its vicinity in the axial direction. 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 the extension catheter of FIG. 1 inserted into a guiding catheter in a curved state. FIG. 11 is a cross-sectional view of the tubular member of FIG. 1 taken along XI-XI. FIG. 12 is a side view of the extension catheter of FIG. 1 having a radiopaque ring. Fig. 13 is a side view of a linear member and a tubular member when the distal end of the linear member coated with a first resin is placed on the outer surface of the tubular member. Fig. 14 is a side view of the linear member and the tubular member when the distal end of the linear member coated with the first resin of Fig. 13 and the tubular member are surrounded by a fixing heat-shrinkable tube. Fig. 15 is a side view of the linear member and the tubular member when the fixing heat-shrinkable tube of Fig. 14 is removed after heat shrinking. Fig. 16 is a side view of a tubular member when a groove is formed on the outer surface of the tubular member. Fig. 17 is a side view of the linear member when the distal end of the linear member coated with the first resin of Fig. 13 is surrounded by a molding heat-shrinkable tube.

[0010] 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.

[0011] An extension catheter according to an embodiment is an extension catheter that is inserted into a catheter and can protrude from an opening on the distal side of the catheter, and has a tubular member and a linear member whose distal end is fixed to the tubular member, and the tubular member includes a first resin having a portion located radially outward from the linear member, and a second resin having a Shore D hardness lower than that of the first resin, and in a radial cross section of the tubular member, when the tubular member is divided into thirds in a direction passing through the centroid of the linear member and the centroid of the lumen of the tubular member and the first, second, and third regions are defined in order of proximity to the linear member, the first resin is located in the first region or the first and second regions, and the second resin is located in at least the third region, and the first resin has a first exposed surface that is exposed on the outer surface of the tubular member.

[0013] Through research by the present inventors, it has been found that arranging a high-hardness resin in a portion of the tubular member close to the linear member so that a portion is exposed improves the hardness of the portion near the linear member and makes the outer surface of the tubular member less likely to twist, thereby improving the transmission of pushing force from the linear member to the tubular member. Furthermore, it has been found that arranging a low-hardness resin in a portion of the tubular member radially distant from the linear member makes the distant portion more likely to deform to conform to the shape of the vessel within the body when the tubular member is pushed into a vessel such as an artery within the body. The tubular member of the extension catheter according to the embodiment has a first region, or the first and second regions, that can improve the transmission of pushing force from the linear member to the tubular member, and a third region that allows the tubular member to easily deform to conform to the shape of the vessel within the body, thereby making it easier to insert the tubular member into a vessel within the body due to the combined effects of these.

[0012]

[0033] An extension catheter according to an embodiment will be described below with reference to Figures 1 to 12. Figure 1 is a side view of an extension catheter according to an embodiment. Figure 2 is a side view of the extension catheter of Figure 1 inserted into a guiding catheter with a portion protruding from the distal opening. Figure 3 is a cross-sectional view of the tubular member of Figure 1 taken along III-III. Figures 4, 5, 6, and 7 are cross-sectional views of modified examples of the tubular member of Figure 1 taken along III-III. Figure 8 is a cross-sectional view of the tapered portion of the extension catheter of Figure 1 and its vicinity in the axial direction. Figure 9 is a side view of the tapered portion of the extension catheter of Figure 1 and its vicinity. Figure 10 is a side view of the extension catheter of Figure 1 inserted into a guiding catheter in a curved state. Figure 11 is a cross-sectional view of the tubular member of Figure 1 taken along XI-XI. Figure 12 is a side view of the extension catheter of Figure 1 having a radiopaque ring.

[0013] 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.

[0014] 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.

[0015] As shown in Figures 3 to 7, the tubular member 1 includes a first resin R1 having a portion located outside the linear member 2 in the radial direction 1D, and a second resin R2 having a lower Shore D hardness than the first resin R1. Furthermore, in a cross section of the tubular member 1 in the radial direction 1D, when the tubular member 1 is divided into three equal parts in a direction passing through the centroid C2 of the linear member 2 and the centroid C1 of the inner cavity 1L of the tubular member 1, and the first, second, and third regions P1, P2, and P3 are defined in order of proximity to the linear member 2, the first resin R1 is located in the first region P1, or the first and second regions P1 and P2. Furthermore, the second resin R2 is located in at least the third region P3. The first resin R1 has a first exposed surface R1s exposed on the outer surface 1S of the tubular member 1. The cross section of the cylindrical member 1 in the radial direction 1D is specifically a cross section of the cylindrical portion 10 of the cylindrical member 1 in the radial direction 1D, and is a cross section that includes at least the first exposed surface R1s and the linear member 2.

[0016] In the cross section of the tubular member 1 in the radial direction 1D, the first region P1 is a region close to the linear member 2, and the first resin R1, which has a relatively high Shore D hardness, is located in the first region P1 of the tubular member 1, thereby improving the hardness of the first region P1. Furthermore, the portion of the outer surface 1S of the tubular member 1 where the first resin R1 is exposed is less likely to twist when the linear member 2 is pushed in. As a result, the transmission of the pushing force can be improved. Meanwhile, in the cross section of the tubular member 1 in the radial direction 1D, the third region P3 is a region far from the linear member 2, and the second resin R2, which has a relatively low Shore D hardness, is included in the third region P3, which makes the third region P3 more likely to deform to conform to the shape of a vessel within the body. These combined effects make it easier to insert the extension catheter 91 into a vessel such as an artery within the body.

[0017] 3, 6, and 7, when the first resin R1 is located in the first region P1, the hardness of the first region P1 is improved. Furthermore, as shown in FIGS. 4 and 5, when the first resin R1 is located in both the first region P1 and the second region P2, the hardness of the first region P1 and the second region P2 is improved. Furthermore, the first resin R1 is not located in the third region P3, which improves the flexibility of the third region P3.

[0018] As shown in Figures 3, 6, and 7, it is preferable that the first exposed surface R1s is exposed in the first region P1. This makes it difficult for the outer surface 1S of the tubular member 1 to twist in the first region P1. Furthermore, as shown in Figures 4 and 5, it is more preferable that the first exposed surface R1s is exposed in the first region P1 and the second region P2. This makes it even more difficult for the outer surface 1S of the tubular member 1 to twist in the first region P1 and the second region P2. Furthermore, the first exposed surface R1s is not exposed in the third region P3, which improves the flexibility of the third region P3.

[0019] As shown in Figures 3 to 7, the second resin R2 is located at least in the third region P3. By positioning the second resin R2, which has a relatively low Shore D hardness, in the third region P3, the flexibility of the third region P3 is improved, making it easier for the tubular member 1 to deform along the shape of a vessel inside the body. It is preferable that the second resin R2 be located at least in the second region P2 and the third region P3. This makes it easier for the tubular member 1 to bend along the shape of a curved portion of a blood vessel or the like inside the body. It is also more preferable that the second resin R2 be located in the first region P1, the second region P2, and the third region P3. This makes it even easier for the tubular member 1 to bend along the shape of a curved portion of a blood vessel or the like inside the body.

[0020] As shown in Figures 3 to 7, it is preferable that the second resin R2 is exposed in at least the third region P3. This improves the flexibility of the third region P3, making it easier for the tubular member 1 to deform along the shape of a vessel inside the body. It is more preferable that the second resin R2 is exposed in at least the second region P2 and the third region P3. This makes it easier for the tubular member 1 to bend along the shape of a curved portion of a blood vessel or the like inside the body. It is even more preferable that the second resin R2 is exposed in the first region P1, the second region P2, and the third region P3. This makes it even easier for the tubular member 1 to bend along the shape of a curved portion of a blood vessel or the like inside the body.

[0021] 3 to 7, in a cross section of the cylindrical member 1 in the radial direction 1D, a straight line L1 passing through the centroid C2 of the linear member 2 and the centroid C1 of the lumen 1L of the cylindrical member 1 preferably intersects the first resin R1. The presence of the first resin R1 with a high Shore D hardness on the straight line L1 passing through each centroid improves the transmission of the pushing force from the linear member 2 to the cylindrical member 1. Similarly, an imaginary plane passing through the central axis 1C of the linear member 2 and the central axis 1C of the cylindrical member 1 preferably bisects the first resin R1.

[0022] 3, 4, 5, and 7, it is preferable that the first resin R1 has a portion located inside the linear member 2 in the radial direction 1D of the cylindrical member 1. In other words, by having the first resin R1 have a portion located outside and a portion located inside the linear member 2 in the radial direction 1D of the cylindrical member 1, the hardness in the vicinity of the linear member 2 is further improved, and therefore pushability is further improved.

[0023] 6, in the radial direction 1D of the tubular member 1, the first resin R1 does not have to have a portion located inside the linear member 2. In this case, the outer diameter of the tubular member 1 can be reduced, and manufacturing efficiency can be further improved.

[0024] 3 to 7, the length of the first exposed surface R1s in the circumferential direction RC is preferably longer than the length of the first resin R1 in the radial direction 1D in a cross section of the tubular member 1 in the radial direction 1D. In this way, the length of the first exposed surface R1s in the circumferential direction RC is longer than the thickness of the first resin R1, which improves the flexibility of the first resin R1 in the radial direction 1D, making it easier for the tubular member 1 to bend in the radial direction 1D when inserted into a curved portion such as a blood vessel inside the body.

[0025] 5 , in a cross section of the cylindrical member 1 in the radial direction 1D, a region on one side and a region on the other side of the cylindrical member 1 are divided by a straight line L1 passing through the centroid C2 of the linear member 2 and the centroid C1 of the lumen 1L of the cylindrical member 1. The length in the circumferential direction RC of the first exposed surface R1s in the one side region may be longer than the length in the circumferential direction RC of the first exposed surface R1s in the other side region. Depending on the shape of a tube inside the body, one side of the cylindrical member 1 may be mainly in contact with the tube. Therefore, if the length in the circumferential direction RC of the first exposed surface R1s in the one side region is longer, it becomes easier to push the cylindrical member 1 into such a tube.

[0026] 3, 4, 5, and 7, at the distal end 2B of the linear member 2, the first resin R1 preferably surrounds the periphery of the linear member 2. This further improves the hardness in the vicinity of the linear member 2, thereby further improving the pushability. In this case, it is preferable that the first resin R1 contacts the linear member 2, but it does not have to contact the linear member 2.

[0027] As shown in FIG. 7 , the tubular member 1 may have a third resin R3, which has a Shore D hardness higher than that of the second resin R2, located closer to the linear member 2 than the first resin R1. The Shore D hardness of the third resin R3 is preferably higher than that of the first resin R1. This can further improve pushability. On the other hand, the Shore D hardness of the third resin R3 may be lower than that of the first resin R1. For example, even if the Shore D hardness of the third resin R3 is low, if the adhesive strength is high, it is possible to maintain the transmission of the pushing force from the linear member 2 to the tubular member 1 via the first resin R1.

[0028] As shown in Figure 7, in the cross section of the cylindrical member 1 in the radial direction 1D, it is preferable that the third resin R3 surrounds the periphery of the linear member 2. This improves the hardness in the vicinity of the linear member 2, further improving pushability. It is also preferable that the third resin R3 be in contact with the linear member 2. Although not shown, both the first resin R1 and the third resin R3 may be in contact with the linear member 2.

[0029] The third resin R3 is preferably located closer to the distal end R1b of the first resin R1 and closer to the proximal end R1a of the first resin R1, but may also be located between the distal end R1b of the first resin R1 and the proximal end R1a of the first resin R1.

[0030] The Shore hardness of each of the first resin R1, the second resin R2, and the third resin R3 can be measured based on the ISO 868:2003 plastic durometer hardness test method using, for example, a type D durometer.

[0031] The second resin R2 preferably has a lower melting point than the first resin R1. This increases the contact area between the second resin R2 and the first resin R1, making it easier to prevent interfacial peeling. Specifically, in the manufacturing process of the extension catheter 91, when the first resin R1 is attached to the linear member 2 and the first resin R1 and the linear member 2 are partially embedded in the second resin R2 of the tubular member 1 while being heated, a low melting point of the second resin R2 makes it easier to achieve partial embedding. As a result, the contact area between the first resin R1 and the second resin R2 can be increased. On the other hand, the second resin R2 may have a higher melting point than the first resin R1. In this case, the first resin R1 melts and spreads more easily when heated during the manufacturing process, making it possible to increase the area of ​​the first exposed surface R1s.

[0032] 8 and 9, it is preferable that the first exposed surface R1s extends in the axial direction 1X of the cylindrical member 1. This further improves the pushability of the cylindrical member 1 in the axial direction 1X.

[0033] As shown in Figures 8 and 9, the distal end R1b of the first resin R1 is preferably located distal to the distal end 2b of the linear member 2, and the proximal end R1a of the first resin R1 is preferably located proximal to the distal end 2b of the linear member 2. This makes it easier to push the tubular member 1 into a vessel within the body via the linear member 2. It is more preferable that the proximal end R1a of the first resin R1 is located at the proximal end 1a of the tubular member 1. It is preferable that the distal end R1b of the first resin R1 is 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. Similarly, it is preferable that the distal end of the first exposed surface R1s is located distal to the distal end 2b of the linear member 2, and the proximal end of the first exposed surface R1s is located proximal to the distal end 2b of the linear member 2. It is more preferable that the proximal end of the first exposed surface R1s is located at the proximal end 1a of the tubular member 1. It is preferable that the distal end of the first exposed surface R1s is located proximal to a point that is 50 mm distal to the distal end 2b of the linear member 2 in the axial direction 1X of the tubular member 1.

[0034] As shown in FIGS. 1 and 9 , 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 1L 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 1L 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. 10 , for example. A treatment catheter such as a balloon catheter or a stent delivery catheter may be used to insert the intravascular treatment device into the opening 11P.

[0035] 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. 8 , 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] As shown in Fig. 9 , in the radial direction 1D of the tubular member 1, the proximal end of the tapered surface of the tapered portion 11 is preferably closer to the linear member 2 than the distal end of the tapered surface. Specifically, the proximal end S1a of the first tapered surface S1 is preferably closer to the linear member 2 than the distal end S1b of the first tapered surface S1. This inclination of the first tapered surface S1 facilitates insertion of an intravascular treatment device through at least an opening 11P located inside the first tapered surface S1. Furthermore, in the radial direction 1D of the tubular member 1, the proximal end of the second tapered surface S2 is preferably closer to the linear member 2 than the distal end of the second tapered surface S2. The proximal end of the third tapered surface S3 may be closer to the linear member 2 than the distal end of the third tapered surface S3, but it is preferable that the third tapered surface S3 be parallel to the linear member 2.

[0042] It is preferable that the distal end R1b of the first resin R1 is located distal to the distal end 11b of the tapered portion 11, and the proximal end R1a of the first resin R1 is located proximal to the distal end 11b of the tapered portion 11. This makes it easier to push the tubular portion 10 and the tapered portion 11 into the body. Similarly, it is preferable that the distal end of the first exposed surface R1s is located distal to the distal end 11b of the tapered portion 11, and the proximal end of the first exposed surface R1s is located proximal to the distal end 11b of the tapered portion 11.

[0043] As shown in Figure 8, the tubular member 1 preferably has an inner layer 10L and an outer layer 10M. The outer layer 10M is a layer located further outward in the radial direction 1D than the inner layer 10L. By having the inner layer 10L and the outer layer 10M, the tubular member 1 can perform different functions on the inside and outside. Note that the inner layer 10L and the outer layer 10M are each cylindrical, but may have a tapered portion.

[0044] The inner layer 10L preferably contains a fluororesin, more preferably is made of a fluororesin, which has excellent chemical resistance, non-stick properties, and low friction. The fluororesin preferably contains polytetrafluoroethylene, ethylene tetrafluoroethylene, fluorinated ethylene propylene, or a combination thereof.

[0045] The outer layer 10M preferably contains a second resin R2. This improves the flexibility of the outer layer 10M. The second resin R2 preferably contains a polyamide resin, a polyester resin, a polyurethane resin, a polyolefin resin, a vinyl chloride resin, a silicone resin, a natural rubber, or a combination thereof, and more preferably contains a polyamide resin, a polyurethane resin, or a combination thereof. The resin may contain an elastomer having rubber elasticity. For example, the polyamide resin may contain a polyamide elastomer, and the polyurethane resin may contain a polyurethane elastomer.

[0046] The outer layer 10M may have multiple layers stacked in the radial direction. Radially adjacent layers among the multiple layers may contain different types of resin, or may contain the same type of resin. The outer layer 10M preferably has a hydrophilic polymer on its outer surface. This facilitates insertion of 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.

[0047] It is preferable that a part of the first resin R1 is embedded in the outer layer 10M, which increases the contact area between the outer layer 10M and the first resin R1, making it easier to prevent interfacial peeling.

[0048] 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.

[0049] As described above, the cylindrical member 1 may have a third resin R3 having a portion closer to the linear member 2 than the first resin R1. The third resin R3 preferably contains a modified polyolefin resin, and more preferably consists of a modified polyolefin resin. The third resin R3 also preferably contains a urethane adhesive, an acrylic adhesive, a silicone adhesive, or a combination thereof. These adhesives are particularly easy to bond when the linear member 2 is made of metal.

[0050] As shown in FIG. 3 and other figures, 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. The cross-sectional shape of the linear member 2 in the thickness direction may vary in shape or size depending on the axial position. For example, the linear member 2 may have a portion that tapers toward the distal side.

[0051] The distal end 2B of the linear member 2 is preferably disposed between the first resin R1 and the outer layer 10M, within the first resin R1, or within the third resin R3 in the radial direction 1D of the tubular member 1. This allows the hardness of the tubular member 1 in the vicinity of the linear member 2 to be improved.

[0052] The inner layer 10L and the outer layer 10M preferably extend in the axial direction 10X from the cylindrical portion 10 to the tapered portion 11. This facilitates smooth curvature in the order from the cylindrical portion 10 to the tapered portion 11.

[0053] It is preferable that the tubular member 1 does not have through holes, grooves, etc. that penetrate the outer and inner surfaces of the tubular portion 10, the tapered portion 11, or both of them. This makes it less likely that the endovascular treatment device will get caught inside the tubular member 1 when being delivered.

[0054] The tubular member 1 preferably has a reinforcing layer 12. Specifically, the tubular member 1 preferably has the reinforcing layer 12 at least in the tubular portion 10. The reinforcing layer 12 can reinforce the tubular portion 10, making it difficult for a guide wire, for example, to penetrate through the tubular portion 10 when the guide wire is inserted into the lumen of the tubular portion 10.

[0055] The reinforcing layer 12 preferably includes a coil, a braided tube, or a combination thereof. Having the reinforcing layer 12 with a coil or a braided tube, or even with a coil and a braided tube, makes the tubular member 1 less likely to be crushed in the radial direction 1D while maintaining flexibility. On the other hand, not having the reinforcing layer 12 with a coil or a braided tube allows the length of the tubular member 1 in the radial direction 1D to be reduced. The braided tube preferably has a mesh structure in which multiple wires are woven so as to intersect with each other. Each wire may be a solid wire or a twisted wire.

[0056] The reinforcing layer 12 preferably includes a metal wire, a fiber, or a combination thereof as the wire material, and more preferably includes a metal wire. The metal wire preferably includes stainless steel, titanium, a nickel-titanium alloy, a nickel-chromium alloy, a cobalt-chromium alloy, a tungsten alloy, or a combination thereof, and more preferably includes stainless steel. The metal wire may include a radiopaque material as described below. The fiber preferably includes polyarylate fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, carbon fiber, or a combination thereof. The fiber may be a monofilament or a multifilament.

[0057] 9, the distal end 2b of the linear member 2 is preferably located distal to the proximal end 12a of the reinforcing layer 12. This increases the length of the portion of the linear member 2 that is fixed to the tubular member 1, thereby improving pushability. Furthermore, when the tubular member 1 is inserted into a curved portion inside the body, the reinforcing layer 12 and the portion proximal to the reinforcing layer 12 tend to curve more smoothly in that order.

[0058] Although not shown, the distal end 2b of the linear member 2 may be located proximal to the proximal end 12a of the reinforcing layer 12. This allows the outer diameter of the tubular portion 10 to be reduced in the area where the reinforcing layer 12 is present. In this case, the distal end 2b of the linear member 2 may be located distal to the distal end S1b of the first tapered surface S1, or may be located proximal to the distal end S1b of the first tapered surface S1. The distal end 2b of the linear member 2 may be located distal to the distal end 11b of the tapered portion 11, or may be located proximal to the distal end 11b of the tapered portion 11.

[0059] 8 and 9, the distal end of the first exposed surface R1s is preferably located distal to the proximal end 12a of the reinforcing layer 12. This can improve pushability.

[0060] 3 and 11 , the length in the circumferential direction RC of the first exposed surface R1s in the cross section in the radial direction 1D of the tubular portion 10 at a portion where the linear member 2 and the reinforcing layer 12 are present is preferably longer than or equal to, and more preferably longer than, the length in the circumferential direction RC of the first exposed surface R1s in the cross section in the radial direction 1D of the tubular portion 10 proximal to the proximal end 12a of the reinforcing layer 12. This makes it easier to transmit the pushing force to the distal side of the tubular portion 10.

[0061] It is more preferable that the tubular member 1 has a reinforcing layer 12 in the tubular portion 10, but does not have a reinforcing layer 12 in the tapered portion 11. This makes the tapered portion 11 more easily bendable. Furthermore, it is preferable that the distal end 12b of the reinforcing layer 12 is located proximal to the distal end of the tubular portion 10, within 5 mm of the distal end of the tubular portion 10. This allows reinforcement up to the vicinity of the distal end of the tubular portion 10.

[0062] 9, the proximal end 12a of the reinforcing layer 12 is preferably located distal to the distal end S1b of the first tapered surface S1. This makes the first tapered surface S1 and its vicinity more easily bendable. It is more preferable that the proximal end 12a of the reinforcing layer 12 is located distal to the distal end 11b of the tapered portion 11. This makes the tapered portion 11 more easily bendable.

[0063] The reinforcing layer 12 is preferably disposed between the inner layer 10L and the outer layer 10M or within the outer layer 10M in the radial direction 1D of the tubular member 1. This makes it difficult for the reinforcing layer 12 to be exposed to the inner cavity of the tubular portion 10.

[0064] 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.

[0065] As shown in FIG. 12 , the tubular member 1 may further include at least one radiopaque ring 13 disposed at the proximal end 12a, the distal end 12b, or both ends of the reinforcing layer 12 so that they are positioned inside. In FIG. 12 , the radiopaque ring 13 is disposed at the distal end 12b of the reinforcing layer 12 and can function as a marker for the vicinity of the distal end of the tubular portion 10 under X-ray fluoroscopy. Although not shown, if the radiopaque ring 13 is disposed at the proximal end 12a of the reinforcing layer 12, the radiopaque ring 13 can function as a marker for the vicinity of the distal end 11b of the tapered portion 11 under X-ray fluoroscopy. The radiopaque ring 13 is preferably disposed between the reinforcing layer 12 and the outer layer 10M in the radial direction 1D of the tubular member 1. This prevents the end of the reinforcing layer 12 from opening, making it easier to prevent the reinforcing layer 12 from being exposed on the outer surface of the tubular member 1.

[0066] 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.

[0067] 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 1L of the tubular member 1 is preferably 1.0 mm or more and 2.2 mm or less.

[0068]

[0033] Below, a method for manufacturing an extension catheter according to an embodiment will be described. The method for manufacturing an extension catheter according to an embodiment includes the steps of: covering the distal end of a linear member with a first resin; arranging the distal end of the linear member on the outer surface of a tubular member containing a second resin having a lower Shore D hardness than the first resin; surrounding at least the distal end of the linear member and the tubular member with a fixing heat-shrinkable tube; and heating to shrink the fixing heat-shrinkable tube, thereby fixing the distal end of the linear member to the tubular member so that a portion of the first resin is exposed from the outer surface of the tubular member. By this manufacturing method, the extension catheter 91 according to the above-described embodiment can be manufactured.

[0069]

[0046] Below, a manufacturing method of an extension catheter according to an embodiment will be described in more detail with reference to Figures 13 to 17. Figure 13 is a side view of a linear member and a tubular member when the distal end portion of the linear member coated with a first resin is disposed on the outer surface of the tubular member. Figure 14 is a side view of the linear member and the tubular member when the distal end portion of the linear member coated with the first resin in Figure 13 and the tubular member are surrounded by a fixing heat-shrinkable tube. Figure 15 is a side view of the linear member and the tubular member when the fixing heat-shrinkable tube in Figure 14 has been removed after heat shrinking. Figure 16 is a side view of a tubular member when a groove has been formed on the outer surface of the tubular member. Figure 17 is a side view of the linear member when the distal end portion of the linear member coated with the first resin in Figure 13 is surrounded by a molding heat-shrinkable tube. The arrow in Figure 13 indicates the direction in which the distal end portion of the linear member is disposed on the outer surface of the tubular member. Figure 16 corresponds to the field of view when viewed from the direction of the arrow in Figure 13.

[0070] 13 , the manufacturing method according to the embodiment includes a step of coating the distal end portion 2B of the linear member 2 with a first resin R1. The first resin R1 is preferably a resin tube, and the distal end portion 2B of the linear member 2 is preferably coated with the first resin R1 by inserting the distal end portion 2B of the linear member 2 into the resin tube. Alternatively, the distal end portion 2B of the linear member 2 may be coated with the first resin R1 by adhering the first resin R1 to the distal end portion 2B of the linear member 2 by coating or the like. Alternatively, the distal end portion 2B of the linear member 2 may be coated with the third resin R3 by coating or the like, and then the distal end portion 2B of the linear member 2 may be inserted into the resin tube of the first resin R1, thereby coating the distal end portion 2B of the linear member 2 with the first resin R1 and the third resin R3. In the covering step, it is preferable to cover the distal end portion 2B of the linear member 2 with the first resin R1 so that the distal end of the linear member 2 is not exposed.

[0071] 13 , the manufacturing method according to the embodiment further includes a step of disposing the distal end 2B of the linear member 2 on the outer surface 1S of the tubular member 1 containing a second resin R2 having a lower Shore D hardness than the first resin R1. In this step, it is preferable to dispose the distal end 2B of the linear member 2 so that the first resin R1 and the second resin R2 are in contact with each other.

[0072] 14 , the manufacturing method according to the embodiment further includes a step of surrounding at least the distal end portion 2B of the linear member 2 and the tubular member 1 with a fixing heat-shrinkable tube 20. In this step, it is preferable to insert the distal end portion 2B of the linear member 2 coated with the first resin R1 into the fixing heat-shrinkable tube 20. More specifically, it is preferable to insert at least the portion where the distal end portion 2B of the linear member 2 coated with the first resin R1 and the tubular member 1 overlap into the fixing heat-shrinkable tube 20.

[0073] The manufacturing method according to the embodiment further includes a step of heating the fixing heat-shrinkable tube 20 to shrink it, thereby fixing the distal end 2B of the linear member 2 to the tubular member 1 so that a portion of the first resin R1 is exposed from the outer surface 1S of the tubular member 1. As shown in FIG. 15 , the fixing heat-shrinkable tube 20 can be removed after this step. It is sufficient that a portion of the first resin R1 is exposed from the outer surface 1S of the tubular member 1 when removed. This allows the first exposed surface R1s to be formed. In this step, for example, by using a fixing heat-shrinkable tube 20 with a low shrinkage rate, it is possible to make a portion of the first resin R1 more easily exposed from the outer surface 1S of the tubular member 1. The heating temperature in this step is preferably equal to or higher than the temperature at which the fixing heat-shrinkable tube 20 begins to shrink and equal to or higher than the melting point of the first resin R1 or the second resin R2. It is also preferable to place a core material inside the tubular member 1 before this step. This makes it less likely for the tubular member 1 to deform when the fixing heat-shrinkable tube 20 is thermally shrunk.

[0074] As shown in FIG. 16 , the manufacturing method according to the embodiment preferably further includes a step of forming a groove 1G on the outer surface 1S of the tubular member 1 prior to the above-mentioned disposing step. Forming the groove 1G facilitates partial embedding of the distal end 2B of the linear member 2 coated with the first resin R1 within the outer surface 1S of the tubular member 1. Particularly when using a fixing heat-shrinkable tube 20 with a low shrinkage rate in the above-mentioned fixing step, forming a groove 1G of an appropriate depth on the outer surface 1S is effective because it facilitates partial embedding of the first resin R1. The groove 1G preferably extends in the axial direction 1X of the tubular member 1. The groove 1G is preferably linear. The groove 1G may be formed on the outer surface 1S of the tubular member 1 using a tool such as a cutter, or may be formed by placing a linear member on the outer surface 1S of the tubular member 1, covering it with a heat-shrinkable tube, and then heat-shrinking the tube. After heat shrinkage, the linear member and the heat-shrinkable tube can be removed. The cross-sectional shape of the linear body in the thickness direction is preferably circular or elliptical.

[0075] As shown in FIG. 17 , the manufacturing method according to the embodiment preferably further includes, after the covering step but before the disposing step, a step of surrounding at least the first resin R1 with a heat-shrinkable molding tube 21, heating the heat-shrinkable molding tube 21, and molding the first resin R1 by shrinking the heat-shrinkable molding tube 21. Because the molded first resin R1 is more likely to be subjected to uniform force, it is easier to control the degree to which the first resin R1 is embedded in the outer surface 1S of the tubular member 1 in the fixing step. The heat-shrinkable molding tube 21 can be removed after the molding step. The cross-sectional shape of the molded first resin R1 in the thickness direction is preferably circular or elliptical. Furthermore, the heating temperature in this step is preferably above the temperature at which the heat-shrinkable molding tube 21 begins to shrink and above the melting point of the first resin R1.

[0076] Although not shown, the manufacturing method according to the embodiment preferably further includes a step of forming a tapered portion by making an incision in the proximal end of the tubular member 1 and removing a portion of the tubular member 1. In this step, the tapered portion is preferably formed so that at least one tapered surface is formed using a cutting tool such as a cutter. The formation of the tapered portion is preferably performed after the step of fixing the distal end 2B of the linear member 2 to the tubular member 1.

[0077] The fixing heat-shrinkable tube 20 and the molding heat-shrinkable tube 21 may each contain a polyolefin resin, a fluororesin, a silicone resin, or a combination thereof.

[0078] For details of the above-mentioned first resin R1, second resin R2, third resin R3, tubular member 1, linear member 2, etc., please refer to the description of the extension catheter 91.

[0079] This application claims the benefit of priority based on Japanese Patent Application No. 2024-032459, filed on March 4, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-032459, filed on March 4, 2024, are incorporated herein by reference.

[0080] DESCRIPTION OF SYMBOLS 1 Cylindrical member 1a Proximal end 1C Central axis 1G Groove 1D Radial direction 1L Lumen 1X Axial direction 2 Linear member 2b Distal end 2B Distal end 3 Handle member 10 Cylindrical portion 10L Inner layer 10M Outer layer 10X Axial direction 11 Tapered portion 11a Proximal end 11b Distal end 11P Opening 12 Reinforcement layer 12a Proximal end 12b Distal end 13 Radiopaque ring 20 Fixing heat shrink tube 21 Molding heat shrink tube 91 Extension catheter 99 Catheter 99Pa Proximal opening 99Pb Distal opening C1 Centroid of lumen L1 Straight line P1, P2, P3 First region, second region, third region R1, R2, R3 First resin, second resin, third resin R1a Proximal end R1b Distal end R1s First exposed surface RC Circumferential direction 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 an opening on the distal side of the catheter, comprising: a tubular member; and a linear member having a distal end fixed to the tubular member, wherein the tubular member comprises a first resin having a portion located radially outward from the linear member, and a second resin having a Shore D hardness lower than that of the first resin, wherein, in a radial cross section of the tubular member, the tubular member is divided into thirds in a direction passing through the centroid of the linear member and the centroid of the lumen of the tubular member, and the first, second, and third regions are defined in order of proximity to the linear member, the first resin is located in the first region or the first and second regions, and the second resin is located in at least the third region, and the first resin has a first exposed surface that is exposed on the outer surface of the tubular member.

2. The extension catheter according to claim 1, wherein in a radial cross section of said tubular member, a straight line passing through the centroid of said linear member and the centroid of the lumen of said tubular member crosses said first resin.

3. The extension catheter according to claim 1 or 2, wherein the first resin has a portion located inside the linear member in the radial direction of the tubular member.

4. The extension catheter according to claim 1 or 2, wherein the first resin surrounds the periphery of the linear member at the distal end of the linear member.

5. An extension catheter according to claim 4, wherein the tubular member has a third resin having a Shore D hardness higher than that of the second resin, at a position closer to the linear member than the first resin.

6. The extension catheter according to claim 1 or 2, wherein said first resin has no portion located inside said linear member in the radial direction of said tubular member.

7. The extension catheter according to claim 1 or 2, wherein said first exposed surface extends in the axial direction of said tubular member.

8. The extension catheter according to claim 1 or 2, wherein, in a radial cross section of said tubular member, the circumferential length of said first exposed surface is longer than the radial length of said first resin.

9. The extension catheter according to claim 1 or 2, wherein said tubular member has an inner layer and an outer layer, said outer layer containing said second resin.

10. The extension catheter according to claim 1 or 2, wherein the second resin has a lower melting point than the first resin.

11. An extension catheter as described in claim 1 or 2, wherein the distal end of the first resin is located distal to the distal end of the linear member, and the proximal end of the first resin is located proximal to the distal end of the linear member.

12. An extension catheter as described in claim 1 or 2, wherein the tubular member has a tubular portion and a tapered portion located proximal to the tubular portion, and 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.

13. The extension catheter of claim 12, wherein the distal end of said first resin is located distal to the distal end of said tapered portion, and the proximal end of said first resin is located proximal to the distal end of said tapered portion.

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

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

16. The extension catheter of claim 14, further comprising at least one radiopaque ring disposed so that the proximal end, the distal end, or both ends of the reinforcing layer are positioned within the proximal end, the distal end, or both ends.

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

18. A method for manufacturing an extension catheter, comprising the steps of: covering a distal end of a linear member with a first resin; arranging the distal end of the linear member on the outer surface of a tubular member containing a second resin having a Shore D hardness lower than that of the first resin; surrounding at least the distal end of the linear member and the tubular member with a fixing heat shrink tube; and heating to shrink the fixing heat shrink tube, thereby fixing the distal end of the linear member to the tubular member so that a portion of the first resin is exposed from the outer surface of the tubular member.

19. The method for manufacturing an extension catheter according to claim 18, further comprising the step of surrounding at least said first resin with a heat-shrinkable molding tube and heating it to shrink said heat-shrinkable molding tube, after said covering step and before said arranging step, thereby molding said first resin.

20. The method of manufacturing an extension catheter according to claim 18 or 19, further comprising the step of forming a groove in the outer surface of said tubular member prior to said positioning step.

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