Support Catheter

Abstract

To provide a support catheter of a novel structure where one end part of a proximal shaft is unlikely to come off of a braid of a distal shaft, and a tube where a member to be fixed is unlikely to come off of the braid.SOLUTION: A support catheter includes: a distal shaft which is formed into a tube shape in which a treatment catheter is insertable and comprises an inner layer, a reinforcement layer around which a plurality of metal wires are wound in one direction and in the other and is formed into a cylindrical mesh-like shape, and an outer layer; and a proximal shaft connected to the distal shaft. The reinforcement layer includes a small pitch part where the wound metal wire pitch is first value and a large pitch part where pitch of the metal wire is second value larger than the first value. One end part of the proximal shaft is fixed to the large pitch part.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to support catheters and tubes that are used in conjunction with treatment catheters and guiding catheters to guide the treatment catheters to the treatment site. [Background technology]

[0002] In percutaneous coronary intervention (PCI), a support catheter may be used along with a treatment catheter and a guiding catheter.

[0003] The support catheter is formed in a tubular shape into which a treatment catheter can be inserted, and has a distal shaft including an inner layer, a reinforcing layer, and an outer layer, and a proximal shaft connected to the distal shaft. The reinforcing layer may be configured to include a tubular braid (for example, see Patent Document 1) formed by winding metal wires or resin wires at a constant pitch. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-82802 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, one possible method for connecting the proximal shaft and the distal shaft is to connect them by fixing one end of the proximal shaft onto the reinforcing layer (braid) of the distal shaft.

[0006] However, if one end of the proximal shaft is fixed onto a braid such as that described in Patent Document 1 above, which is formed by winding multiple wires at a constant pitch, when a longitudinal tensile force is applied to the distal shaft, a load is placed on the fixed portion between the one end of the proximal shaft and the braid (wires), which may cause the one end of the proximal shaft to peel off from the wires and the tip side of the proximal shaft to break through the outer layer and become exposed.

[0007] Therefore, an object of the present invention is to provide a support catheter having a novel structure in which one end of the proximal shaft is less likely to come off the braid of the distal shaft.

[0008] Another object of the present invention is to provide a tube in which a fixed member is unlikely to come off the braid. [Means for solving the problem]

[0009] A support catheter according to a first aspect is used together with a treatment catheter for treating a treatment site and a guiding catheter into which the treatment catheter is inserted and which guides the treatment catheter within a blood vessel, the support catheter being inserted from a base end opening of the guiding catheter and having a length that protrudes from a tip end opening of the guiding catheter, and guiding a tip portion of the treatment catheter to the treatment site, the support catheter comprising: a distal shaft formed in a tubular shape into which the treatment catheter can be inserted and including an inner layer and a reinforcing layer in which a plurality of metal wires are wound in one direction and another direction to form a cylindrical mesh shape; and a proximal shaft connected to the distal shaft, the reinforcing layer including a small pitch portion in which the pitch of the wound metal wire is a first value and a large pitch portion in which the pitch of the wound metal wire is a second value larger than the first value, and one end of the proximal shaft is fixed to the large pitch portion.

[0010] According to this aspect, the reinforcing layer is provided with a large pitch portion, and one end of the proximal shaft is fixed to the large pitch portion, whereby when a tensile force is applied to the distal shaft in the longitudinal direction, the load on the fixed portion can be made smaller than when one end of the proximal shaft is fixed to the small pitch portion.

[0011] By fixing one end of the proximal shaft onto the braid of the distal shaft, the angle of the metal wire of the braid in the fixed portion is fixed. When a conventional distal shaft having a braid formed by winding at a constant pitch as a reinforcing layer is pulled in the longitudinal direction, the braid gradually changes in the direction in which the pitch becomes larger (the angle of the metal wire becomes larger) in the portion not fixed by the proximal shaft, while the braid cannot follow the change in the portion in which the angle of the metal wire is fixed. Therefore, a load is applied to the fixed portion, which is the boundary between the variable portion in which the pitch changes and the non-variable portion in which the pitch does not change. In contrast, the distal shaft constituting the support catheter according to this embodiment is fixed in a state in which the braid pitch (angle of the metal wire) is increased in advance, so that even when pulled in the longitudinal direction, the load on the fixed portion caused by the change in the braid (change in the braid pitch or the angle of the metal wire) in the portion not fixed by the proximal shaft is suppressed. This makes it difficult for one end of the proximal shaft to peel off from the metal wire.

[0012] A second aspect is a support catheter according to the first aspect, wherein the reinforcing layer includes two of the small pitch sections and a large pitch section located between the two small pitch sections.

[0013] According to this embodiment, the area where the large pitch section, which is harder than the small pitch section, is provided is limited to the area where one end of the proximal shaft is fixed, and the area proximal to the said area is made the small pitch section, thereby ensuring flexibility of the distal shaft and preventing breakage.

[0014] A third aspect is a support catheter according to the first aspect, which includes a gradually changing pitch section between the small pitch section and the large pitch section, in which the pitch of the wound metal wire becomes smaller as it moves from the large pitch section to the small pitch section.

[0015] According to this embodiment, since the braid pitch gradually changes between the large pitch section and the small pitch section, a sudden change in hardness of the distal shaft can be avoided and breakage can be prevented. From the viewpoint of ensuring flexibility, the gradually changing pitch section is preferably short, and from the viewpoint of gradual change in hardness, the gradually changing pitch section is preferably long.

[0016] A fourth aspect is a support catheter according to the first aspect, wherein one end of the proximal shaft is fixed at at least two or more intersections arranged in the axial direction at the large pitch portion where the metal wire wound in one direction intersects with the metal wire wound in the other direction.

[0017] According to this embodiment, one end of the proximal shaft is fixed at at least two points in the large pitch section, so that even if one end of the proximal shaft peels off from the fixed position located at the tip side where the greatest load is applied, the proximal shaft and the distal shaft will not immediately separate.

[0018] The fifth aspect is a support catheter according to the first aspect, wherein the acute angle formed by the wound metal wire in the large pitch portion under normal conditions and a straight line perpendicular to the longitudinal direction of the inner layer is greater than or equal to 25° and less than or equal to 70°.

[0019] According to this embodiment, the closer the acute angle is to 90°, the greater the tensile strength of the distal shaft in the longitudinal direction, and the closer the acute angle is to 0°, the greater the flexibility of the distal shaft, making it easier for it to move in the radial direction.

[0020] A tube according to a sixth aspect comprises a tubular inner layer and a reinforcing layer provided on the outer surface of the inner layer and formed by winding a plurality of metal wires in one direction and another direction to form a cylindrical mesh shape, the reinforcing layer including a small pitch portion in which the pitch of the wound metal wires is a first value and a large pitch portion in which the pitch of the wound metal wires is a second value larger than the first value, and further including a fixed member fixed to the large pitch portion.

[0021] According to this embodiment, the reinforcing layer is provided with a large pitch portion, and the fixed member is fixed to the large pitch portion. This makes it possible to reduce the load on the fixed portion when a tensile force is applied to the tube in the longitudinal direction, compared to when one end of the fixed member is fixed to the small pitch portion. This reduces the load on the fixed portion, as described above, and makes it difficult for the fixed member to peel off from the metal wire (braid). Effect of the Invention

[0022] According to the present invention, it is possible to provide a support catheter having a novel structure in which one end of the proximal shaft is unlikely to come off the braid of the distal shaft, and a tube in which a fixed member is unlikely to come off the braid. [Brief description of the drawings]

[0023] [Figure 1] 1A-1C show a support catheter according to an embodiment of the present invention in use with a treatment catheter and a guiding catheter. [Diagram 2] FIG. 2 is a side view of the support catheter of FIG. 1. [Diagram 3] 1 is a photograph of a distal shaft without an outer layer. [Figure 4] FIG. 2 is a diagram of a distal shaft without an outer layer. [Diagram 5] 1 is a graph showing the relationship between braid pitch and metal wire angle in a large pitch portion. [Figure 6] FIG. 2 shows a fixing point in a reinforcing layer at one end of a proximal shaft. [Figure 7] FIG. 1(a) is a diagram showing the reinforcing layer of a conventional support catheter, and FIG. 1(b) is a diagram showing the state of the reinforcing layer when the proximal shaft of (a) is pulled. [Figure 8] FIG. 1(a) is a diagram showing the reinforcing layer of the support catheter of this embodiment, and FIG. 1(b) is a diagram showing the state of the reinforcing layer when the proximal shaft of (a) is pulled. [Figure 9] FIG. 2 is a side view showing a tube according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] A support catheter according to an embodiment of the present invention will be described below with reference to the drawings. The support catheter described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiment, and additions, deletions, and modifications are possible within the scope of the present invention. In addition, the concept of direction used in the following description is used for convenience in the description, and does not limit the orientation of the configuration of the invention to that direction.

[0025] Percutaneous coronary intervention (PCI), for example, is known as a procedure for dilating a stenosis 3 formed in a coronary artery 2 as shown in Fig. 1. In PCI, a guiding catheter 4, a balloon catheter 5, the support catheter 1 of this embodiment, and a guidewire 25 are mainly used. Each member used in PCI will be described below.

[0026] <Guiding catheter> The guiding catheter 4 is a catheter for guiding the balloon catheter 5 and the support catheter 1 inside a blood vessel, and is inserted into, for example, the radial artery 8 or the femoral artery (not shown) using a sheath 7. The guiding catheter 4 has a guiding catheter main body 11 and a Y-shaped connector 12. The guiding catheter main body 11 has a long tubular shape, and is configured so that the balloon catheter 5 and the support catheter 1 can be inserted into the guiding catheter main body 11. The guiding catheter main body 11 is made of a bendable cylindrical flexible tube, and is capable of being pushed through a curved blood vessel.

[0027] The Y-shaped connector 12 is provided at the base end of the guiding catheter main body 11. The Y-shaped connector 12 has a main body portion 12a and a side arm 12b, and a medicinal solution or a contrast medium can be injected through the side arm 12b. The tip portion of the main body portion 12a is attached to the base end of the guiding catheter main body 11. The main body portion 12a has a base end opening 12c, and the balloon catheter 5 and the support catheter 1 can be inserted through this base end opening 12c.

[0028] <Balloon catheter> The balloon catheter 5 is a treatment catheter, and a known one can be used. The balloon catheter 5 is a catheter that is inserted into a stenotic portion 3 in a coronary artery to expand the stenotic portion 3. The balloon catheter 5 is, for example, a rapid exchange type (RX type) catheter, and has a treatment catheter body 21 and a connector 22 as shown in FIG. 1. The treatment catheter body 21 is formed in a long tubular shape. The treatment catheter body 21 has a balloon 23 with a stent 24 mounted on its tip portion. The balloon catheter 5 is used together with a guidewire 25, a guiding catheter 4, and a support catheter 1.

[0029] <How to use the support catheter> The method of approaching from the radial artery in PCI will be described below with reference to Figure 1. The detailed configuration of the support catheter will be described later.

[0030] In this method, a support catheter 1, a guiding catheter 4, a balloon catheter 5, and a guide wire 25 are used. In PCI, the surgeon first punctures the radial artery 8 with a needle (not shown) and inserts a sheath 7 into the puncture site. After that, when the guiding catheter 4 is inserted into the radial artery 8 through the sheath 7, the guiding catheter 4 is advanced until its distal opening 4a passes through the aortic arch 9 and reaches the inlet 2a of the coronary artery 2. When the distal opening 4a reaches the inlet 2a, the guide wire 25 is inserted and the support catheter 1 is inserted from the proximal opening 4b of the guiding catheter 4. While being pushed and pulled by the surgeon, the support catheter 1 is advanced through the guiding catheter 4 while being guided by the guide wire 25 until its distal portion protrudes from the distal opening 4a. As a result, the distal portion of the support catheter 1 is inserted into the coronary artery 2 and further reaches the stenosis portion 3.

[0031] After the distal portion of the support catheter 1 has been pushed into the stenosis 3 in this manner, the balloon catheter 5 is inserted from the proximal opening 4b of the guiding catheter 4. The balloon catheter 5 has its distal end inserted into the distal shaft 33, and is then pushed forward until it protrudes from the distal shaft 33. By pushing forward in this manner, the distal portion of the balloon catheter 5 is inserted into the stenosis 3, and the balloon 23 and stent 24 are positioned at the stenosis 3. Then, pushing of the balloon catheter 5 is stopped.

[0032] By pushing the balloon catheter 5 forward in this manner, the tip of the balloon catheter 5 is guided by the guiding catheter 4 to the entrance 2a of the coronary artery 2, and is further guided beyond the entrance 2a to the stenosis 3 by the support catheter 1. Since the distal shaft 33 of the support catheter 1 extends to the stenosis 3 or close to it, the tip of the balloon catheter 5 is supported by the tip of the distal shaft 33 when the tip of the balloon catheter 5 is pushed into the stenosis 3. The balloon 23 is then inflated by the pressurized fluid. At the same time, the stent 24 is deployed and expanded to expand the stenosis 3. By this method, the blood flow at the stenosis 3 can be restored.

[0033] <Support catheter> Next, the configuration of the support catheter in this embodiment will be described. As described above, the support catheter 1 is a catheter that is advanced to a position close to the stenosis 3 and serves to guide the balloon 23 of the balloon catheter 5 to the stenosis 3. The support catheter 1 is also a catheter that supports the balloon 23 when the balloon 23 is inserted into the stenosis 3. Such a support catheter 1 is inserted from the base end opening 4b of the guiding catheter 4 and has a length that protrudes from the tip end opening 4a of the guiding catheter 4.

[0034] As shown in FIG. 2, the support catheter 1 includes a protective member 32, a distal shaft 33, and a proximal shaft 34 connected to the distal shaft 33.

[0035] The proximal shaft 34 is a long wire made of a metal such as stainless steel or a synthetic resin such as polyimide or polyether ether ketone. The surface of the proximal shaft 34 is coated with, for example, PTFE. The protective member 32 is provided at the base end of the proximal shaft 34. The protective member 32 is a cylindrical member made of polyamide elastomer or the like.

[0036] The distal shaft 33 is formed in a roughly cylindrical shape, and is configured to allow the insertion of a balloon catheter 5. As shown in Fig. 3, the distal shaft 33 is a member having a three-layer structure including, from the inside, an inner layer 35, a reinforcing layer 36, and an outer layer 37 (Fig. 2).

[0037] The inner layer 35 of the distal shaft 33 is formed of, for example, polytetrafluoroethylene (PTFE) or tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA). The inner layer 35 is manufactured, for example, by applying PTFE to the outer surface of a silver-plated copper wire to form the inner layer 35. Note that the material of the inner layer 35 is not limited to those mentioned above.

[0038] The reinforcing layer 36 of the distal shaft 33 is formed by winding a plurality of metal wires (strands) 36a, for example made of stainless steel, in one direction and another direction into a cylindrical mesh shape (cylindrical net shape), and is provided on the outer peripheral surface of the inner layer 35.

[0039] The outer layer 37 of the distal shaft 33 is formed in a roughly cylindrical shape, and is made of, for example, a nylon-based elastomer resin or polybutylene terephthalate. It is preferable that the base end portion of the outer layer 37 is cut obliquely as shown in FIG. 2, or formed in an arc or crescent shape. In this case, it is preferable that the base end portion of the inner layer 35 is also formed in a similar shape. This makes it easier to insert the balloon catheter 5 into the distal shaft 33. Although the number of outer layers is one, this is not limited to this, and two or more outer layers may be used. The material of the outer layer 37 is not limited to the above.

[0040] The inner layer 35 and the outer layer 37 may be made of the same material, and are not limited to the materials described above. The outer peripheral surface of the outer layer 37 may be coated with a hydrophilic polymer containing polyurethane, polyvinylpyrrolidone (PVP), or the like.

[0041] A distal tip 38 is provided at the distal end of the distal shaft 33. The distal tip 38 is made of a polyamide elastomer containing, for example, bismuth oxide, which is a contrast agent, and is formed in a roughly cylindrical shape. The distal tip 38 is radiopaque, and a shadow appears under fluoroscopy.

[0042] Here, the reinforcing layer 36 provided on the outer peripheral surface of the inner layer 35 of the distal shaft 33 will be described in detail.

[0043] When forming the reinforcing layer 36, for example, 16 metal wires 36a are used. Eight of the 16 metal wires 36a are spirally wound in one direction on the outer peripheral surface of the inner layer 35, and the remaining eight are spirally wound in the other direction on the outer peripheral surface of the inner layer 35, thereby forming the reinforcing layer 36. Note that the number of metal wires 36a to be wound is not limited to eight in each direction. In addition, the method of winding the metal wires 36a is not limited to a spiral shape, and any conventionally known method can be used.

[0044] As shown in FIG. 3 and FIG. 4, the reinforcing layer 36 includes a large pitch portion 50, two gradually changing pitch portions 51, and two small pitch portions 52. For example, the length of the large pitch portion 50 can be 1 to 30 mm, the length of the small pitch portion 52 on the tip side can be 200 to 500 mm, the length of the small pitch portion 52 on the base end side can be 0 to 30 mm, and the length of each gradually changing pitch portion 51 can be 1 to 5 mm. However, the length of each portion is appropriately set depending on the blood vessel portion to which the support catheter 1 is applied, and is not limited thereto. From the viewpoint of ensuring flexibility, the gradually changing pitch portion 51 is preferably short, and from the viewpoint of gradual hardness change, the gradually changing pitch portion 51 is preferably long.

[0045] The large pitch section 50 is disposed between two small pitch sections 52. Moreover, one gradually changing pitch section 51 is disposed between one small pitch section 52 and the large pitch section 50, and the other gradually changing pitch section 51 is disposed between the other small pitch section 52 and the large pitch section 50.

[0046] The small pitch portion 52 is a portion where the braid pitch (pitch) is a first value. The braid pitch is the interval between one portion and the other portion of one metal wire 36a wound in one direction (or the other direction) that are adjacent to each other in the axial direction and have the same phase (for example, 0° position, but may be any angle position) in the circumferential direction on the reinforcing layer 36. In other words, it is the interval from one portion at the 0° position to the other portion that is next positioned at the same 0° position by the winding of the metal wire 36a. The first value may be a value smaller than a second value that the large pitch portion 50 described later can take, and is appropriately set depending on the blood vessel portion to which the support catheter 1 is applied, and is not limited thereto.

[0047] On the other hand, the large pitch portion 50 is a portion where the braid pitch is a second value larger than the first value. As shown in Fig. 7(a) described later, an acute angle (metal wire angle) α between one metal wire 36a in the large pitch portion 50 and a straight line L perpendicular to the length direction of the proximal shaft 34 in a normal state is, for example, 25° to 70° in plan view, and when the angle α is within this range, the possible range of the second value is, for example, 2 to 10 mm as shown in Fig. 5. Note that the support catheter 1 in the normal state is in a state where it is housed in a package, or in a state where it has been taken out of the package and is unused and unloaded.

[0048] Moreover, the gradually changing pitch portion 51 is a portion in which the braid pitch decreases from the large pitch portion 50 toward the small pitch portion 52. For example, when the braid pitch of the large pitch portion 50 is 6 mm and the braid pitch of the small pitch portion 52 is 2 mm, the braid pitch of the gradually changing pitch portion 51 gradually changes in the range from 6 mm to 2 mm.

[0049] In this embodiment, one end of the proximal shaft 34 is welded to the large pitch portion 50 and the small pitch portion 52 on the base end side. In detail, the one end of the proximal shaft 34 is fixed at at least two or more intersections of the metal wire 36a wound in one direction and the metal wire 36a wound in the other direction, which are arranged in the axial direction, in the large pitch portion 50. The fixing method is, for example, welding, but is not limited to this. In this case, as shown in FIG. 6, the one end of the proximal shaft 34 is welded to every other intersection of the plurality of intersections in the large pitch portion 50. The symbol P in FIG. 6 indicates a welding point. Also, the one end of the proximal shaft 34 is welded to every other intersection of the plurality of intersections in the small pitch portion 52. Note that, as shown in FIG. 8(a) described later, the one end of the proximal shaft 34 may be welded to every other intersection in the large pitch portion 50 and the small pitch portion 52.

[0050] Next, the action and the effect of the support catheter 1 of this embodiment will be described with reference to Figs. 7 and 8. Figs. 7 and 8 are schematic diagrams that, although lacking in accuracy, are expressed with priority given to easy understanding of the action and effect. When a conventional distal shaft 133 having a reinforcing layer (conventional reinforcing layer) 136 with a constant braid pitch as shown in Fig. 7(a) is pulled in the direction of the arrow shown in Fig. 7(b), the braid 136 gradually changes in the direction in which the braid pitch increases (the angle of the metal wire 36a increases) in the portion not fixed by the proximal shaft 34, while the braid 136 cannot follow the change in the portion in which the angle of the metal wire 36a is fixed. Therefore, a load is applied to the fixed portion P1, which is the boundary between the variable portion where the braid pitch changes and the non-variable portion where the pitch does not change. Therefore, one end of the proximal shaft 34 is easily peeled off from the metal wire 36a.

[0051] In contrast, the large pitch portion 50 of the distal shaft 33 constituting the support catheter 1 of this embodiment has a large braid pitch in advance, so that even if the distal shaft 33 of this embodiment shown in Fig. 8(a) is pulled in the direction of the arrow shown in Fig. 8(b), the load on the fixed portion P2 caused by changes in the braid 36 (changes in braid pitch and angle of the metal wire 36a) in the portion not fixed by the proximal shaft 34 is suppressed. This makes it difficult for one end of the proximal shaft 34 to peel off from the metal wire 36a. Note that the gradually changing pitch portion 51 is not shown in Fig. 8.

[0052] As described above, according to the support catheter 1 of this embodiment, the reinforcing layer 36 is provided with the large pitch portion 50, and one end of the proximal shaft 34 is fixed to the large pitch portion 50. This makes it possible to reduce the load on the fixed portion of the large pitch portion 50 at one end of the proximal shaft 34 when a tensile force in the longitudinal direction is applied to the distal shaft 34, compared to when one end of the proximal shaft 34 is fixed to the small pitch portion 52. This makes it difficult for one end of the proximal shaft 34 to peel off from the metal wire 36a.

[0053] In addition, in this embodiment, a gradually changing pitch section 51 is provided between the large pitch section 50 and the small pitch section 52, so that the braiding pitch gradually changes between the large pitch section 50 and the small pitch section 52, thereby avoiding a sudden change in hardness of the distal shaft 33 and preventing breakage.

[0054] In addition, in this embodiment, the proximal shaft 34 is welded to the large pitch portion 50 and the small pitch portion 52 on the base end side, so that the welded area of ​​the proximal shaft 34 can be increased. Therefore, the possibility that the proximal shaft 34 will peel off can be reduced.

[0055] Furthermore, in this embodiment, one end of the proximal shaft 34 is fixed at at least two points in the large pitch section 50, so that even if one end of the proximal shaft 34 peels off from the fixed position located at the tip side where the greatest load is applied, the proximal shaft 34 and the distal shaft 33 will not immediately separate.

[0056] In this embodiment, one end of the proximal shaft 34 is welded to every other intersection in the large pitch portion 50, and to every two or more intersections in the small pitch portion 52. In this case, manufacturing is easier than when one end of the proximal shaft 34 is welded to every plurality of intersections in the large pitch portion 50 and the small pitch portion 52.

[0057] Furthermore, in this embodiment, by setting the above-mentioned acute angle α in the large pitch section 50 to be greater than or equal to 25° and less than or equal to 70°, the tensile strength of the distal shaft 33 in the longitudinal direction increases as the acute angle α approaches 90°, and the flexibility of the distal shaft 33 increases as the acute angle α approaches 0°, making it easier for the distal shaft 33 to move in the radial direction.

[0058] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present invention. For example, the following modifications are possible.

[0059] In the above embodiment, the gradually changing pitch section 51 is provided between one small pitch section 52 and the large pitch section 50 and between the other small pitch section 52 and the large pitch section 50, but this is not limited to this, and the gradually changing pitch section 51 may be provided at least between one small pitch section 52 and the large pitch section 50 and between the other small pitch section 52 and the large pitch section 50.

[0060] In the above embodiment, one end of the proximal shaft 34 is fixed to the large pitch portion 50 of the reinforcing layer 36 and the small pitch portion 52 on the base end side, but this is not limited to this. In addition to these, one end of the proximal shaft 34 may also be fixed to the gradually changing pitch portion 51 on the tip end side, or may be fixed only to the large pitch portion 50.

[0061] In the above embodiment, the support catheter 1 in which one end of the proximal shaft 34 is fixed to the large pitch portion 50 of the reinforcing layer 36 has been described, but the present invention is not limited to this, and the fixed member may be fixed to the large pitch portion of the reinforcing layer in the tube. In detail, as shown in FIG. 9, the tube 100 includes a tubular inner layer 135 and a reinforcing layer 36 provided on the outer surface of the inner layer 135 and formed into a cylindrical mesh shape by winding a plurality of metal wires 36a in one direction and the other direction. The reinforcing layer 36 includes a small pitch portion 52, a gradually changing pitch portion 51, and a large pitch portion 50, as described above. The tube 100 further includes a fixed member 134 fixed to the large pitch portion 50. The tube 100 may include a tubular outer layer on the outside of the reinforcing layer 36. Such a tube 100 has the same effect as the support catheter 1 described above.

[0062] Furthermore, in the above embodiment, a tip tip 38 is provided at the tip of the distal shaft 33, but when the tip tip 38 is welded to the reinforcing layer 36 of the distal shaft 33, the area including the weld point may be configured as a large pitch section having a larger braid pitch than the remaining section. [Explanation of symbols]

[0063] 1 Support Catheter 4 Guiding catheter 5 Balloon Catheter 33 Distal shaft 34 Proximal Shaft 35,135 Inner layer 36 Reinforcement layer 36a metal wire 37 Outer layer 50 Large pitch section 51 Gradual pitch change section 52 Small pitch section 100 tubes 134 Fixed member

Claims

1. A support catheter for treating a treatment site, the support catheter being used together with a guiding catheter into which the treatment catheter is inserted and which guides the treatment catheter within a blood vessel, the support catheter being inserted from a base end opening of the guiding catheter and having a length protruding from a tip end opening of the guiding catheter, and guiding a tip portion of the treatment catheter to the treatment site, a distal shaft formed in a tubular shape into which the treatment catheter can be inserted, the distal shaft including an inner layer and a reinforcing layer formed in a cylindrical mesh shape by winding a plurality of metal wires in one direction and another direction; a proximal shaft connected to the distal shaft, the reinforcing layer includes a small pitch portion on a tip side, in which the pitch of the wound metal wire is a first value, and a large pitch portion on a base end side of the small pitch portion, in which the pitch of the wound metal wire is a second value larger than the first value, A support catheter, wherein one end of the proximal shaft is fixed to the large pitch section.

2. The support catheter of claim 1 , wherein the reinforcing layer includes two of the small pitch sections and the large pitch section located between the two small pitch sections.

3. A gradually varying pitch portion is included between the small pitch portion and the large pitch portion, The support catheter according to claim 1 or 2, wherein the gradually varying pitch section has a pitch of the wound metal wire that becomes smaller from the large pitch section toward the small pitch section.

4. 4. The support catheter according to claim 1, wherein one end of the proximal shaft is fixed in the large pitch section at at least two or more intersections arranged in the axial direction where the metal wire wound in one direction intersects with the metal wire wound in the other direction.

5. 5. The support catheter according to claim 1, wherein the acute angle formed by the wound metal wire in the large pitch portion under normal conditions and a straight line perpendicular to the longitudinal direction of the inner layer is greater than or equal to 25° and less than or equal to 70°.

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