JP7577999B2 - Support Catheter - Google Patents

Description

The present invention relates to a rapid exchange type support catheter that is used together with a treatment catheter and a guiding catheter to guide the treatment catheter to a treatment site.

In percutaneous coronary intervention (PCI), a support catheter may be used along with a treatment catheter and a guiding catheter. Known examples of support catheters include the catheter described in Patent Document 1.

The support catheter in Patent Document 1 has a distal shaft (referred to as a tubular body in the document) and a proximal shaft (referred to as a wire in the document). The distal shaft and the proximal shaft are connected in a state where the tip end portion of the proximal shaft and the base end portion of the distal shaft overlap partially along the longitudinal direction. In detail, the distal shaft and the proximal shaft are connected by covering the outer periphery of the overlapping portion with a reinforcing tube.

JP 2004-275435 A

However, in the support catheter of Patent Document 1, the distal end portion of the proximal shaft is overlapped with the outer circumferential surface of the distal shaft, so that the diameter of the entire support catheter is large. Furthermore, the outer circumferential surface of the overlapping portion is covered with a reinforcing tube, so that the diameter of the entire support catheter is further increased. Therefore, when performing a procedure using two guidewires, a guiding guidewire for guiding the support catheter in the guiding catheter and a protective guidewire used to prevent occlusion of the coronary artery branch point due to balloon inflation, it becomes extremely difficult to place both the support catheter and the protective guidewire, which have a large diameter as described above, in the lumen of the guiding catheter. In addition, as another procedure using two guidewires, for example, in a tortuous coronary artery blood vessel, in addition to the guiding guidewire placed in the lumen of the support catheter, there is a procedure using another guidewire placed along the outer surface of the support catheter (sometimes called the buddy wire technique). This procedure reduces the contact of the support catheter with the inner circumferential surface of the blood vessel, improving the passability of the support catheter. Even when performing such a procedure, it is not preferable to increase the diameter of the support catheter because two guide wires are placed in the lumen of the guiding catheter. Furthermore, when a procedure is started using a small-diameter guiding catheter and then changed to a procedure using two guide wires as described above due to severe tortuosity or large stenosis of the blood vessel, the conventional support catheter has a large diameter, so that two guide wires cannot be inserted into the lumen of the guiding catheter having a smaller diameter. Therefore, it is necessary to use a larger-diameter guiding catheter instead of the small-diameter guiding catheter, and in such a case, the sheath must be replaced and the procedure must be started over from the beginning.

Therefore, the present invention aims to provide a support catheter that has a smaller overall diameter than conventional support catheters without reducing the inner diameter of the distal shaft, and that can further improve the strength of the connection between the distal shaft and the proximal shaft.

The support catheter according to the first aspect is a support catheter 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 which is comprised of an inner layer, a reinforcing layer, and an outer layer, and a proximal shaft whose tip portion is located in a portion of the distal shaft that is more inner than the outer layer, and the tip portion of the proximal shaft is formed to be wider than the remaining portion.

According to this embodiment, the distal portion of the proximal shaft is disposed inside the outer layer of the distal shaft, so that it is possible to reduce the outermost diameter (length in the direction perpendicular to the axial direction) of the support catheter compared to conventional methods without reducing the inner diameter of the distal shaft. In addition, the distal portion of the proximal shaft is formed to be wide, so that the contact area between the distal portion and the distal shaft can be increased. This increases the strength of the fixed portion, making it difficult for the distal portion of the proximal shaft to come off the distal shaft.

The second aspect is a support catheter according to the first aspect, in which the reinforcing layer of the distal shaft is made of a plurality of metal wires formed into a tubular mesh shape, and the tip portion of the proximal shaft is fixed to at least one of the plurality of metal wires.

In this embodiment, as described above, the tip portion of the proximal shaft is formed to be wide, making it easier to fix the tip portion to a thin metal wire.

A third aspect is a support catheter according to the first aspect, in which the tip portion of the proximal shaft is formed in a ring shape whose axial direction is aligned with the axial direction of the proximal shaft.

In this embodiment, the tip portion of the proximal shaft is formed into an annular shape, thereby making it possible to increase the contact area with the distal shaft.

The fourth aspect is a support catheter according to the first aspect, in which the tip portion of the proximal shaft is formed in a C-ring shape with its axis aligned along the axis of the proximal shaft and with a portion of the ring cut out.

According to this embodiment, the tip portion of the proximal shaft is formed in a C-ring shape, thereby making it possible to increase the contact area with the distal shaft.

The fifth aspect is a support catheter according to the first aspect, wherein the tip portion of the proximal shaft is configured to include a contrast marker.

According to this embodiment, it is easy to recognize the state of passage of the distal end portion of the proximal shaft through the guiding catheter. It also serves as a marker for the proximal opening of the distal shaft when inserting the treatment catheter into the distal shaft.

A sixth aspect is a support catheter according to the first aspect, wherein the metal wire and the proximal shaft are formed from stainless steel.

According to this embodiment, it becomes easier to fix the metal wire and the tip portion of the proximal shaft together, for example by welding.

The seventh aspect is a support catheter according to the first aspect, in which the tip portion of the proximal shaft is sandwiched between the inner layer and the outer layer of the distal shaft.

In this embodiment, the connection strength can be improved by sandwiching the tip portion of the proximal shaft between the inner and outer layers of the distal shaft.

The eighth aspect is a support catheter according to the first aspect, wherein the outer layer of the distal shaft includes a first constituent outer layer and a second constituent outer layer arranged adjacent to each other along the axial direction of the distal shaft, the first constituent outer layer either containing or not containing the distal portion of the proximal shaft, and the second constituent outer layer containing the distal portion of the proximal shaft.

According to this embodiment, since the outer layer is composed of two or more constituent outer layers, the physical properties of the distal shaft, such as its flexibility, can be changed stepwise in the axial direction by changing the raw materials of each constituent outer layer. In addition, it becomes easier to arrange the metal wire and the tip portion of the proximal shaft before the second constituent outer layer is provided. Furthermore, after the metal wire and the tip portion of the proximal shaft are fixed to each other, the tip portion of the proximal shaft is difficult to remove from the metal wire by enclosing the tip portion of the proximal shaft in the first constituent outer layer.

A ninth aspect is a support catheter according to the first aspect, wherein the second component outer layer has a higher hardness than the first component outer layer.

According to this embodiment, the connection between the metal wire and the distal end portion of the proximal shaft can be made stronger, and the flexibility of the distal end portion of the distal shaft can be ensured, so that the support catheter can be pushed forward smoothly. In addition, the hardness of the distal shaft can be changed in stages from the base end portion to the distal end portion, so that kinking due to a sudden change in hardness can be avoided.

According to the present invention, it is possible to provide a support catheter in which the overall diameter of the support catheter is smaller than that of conventional support catheters without reducing the inner diameter of the distal shaft, and in which the strength of the connection between the distal shaft and the proximal shaft can be further improved.

1A-1C show a support catheter according to an embodiment of the present invention in use with a treatment catheter and a guiding catheter. FIG. 2 is a side view of the support catheter of FIG. 1. 5A and 5B are diagrams illustrating a manufacturing process of the support catheter of the first embodiment. 1 is a plan view showing a distal end portion of a proximal shaft of a support catheter according to a first embodiment. FIG. 6A and 6B are diagrams illustrating a manufacturing process of a support catheter according to a second embodiment. 13( a ) and 13 ( b ) are diagrams illustrating a manufacturing process of a support catheter according to a third embodiment. 13( a ), ( b ), and ( c ) are diagrams illustrating a manufacturing process of a support catheter according to a fourth embodiment. FIG. 13 is a diagram showing a modified example of the support catheter of the fourth embodiment. 13A is a side view showing the configuration of a mold for forming a tip portion of a proximal shaft of a fifth embodiment, and FIG. 13B is a side view showing the proximal shaft formed by the mold of FIG. FIG. 13 is a plan view showing a laser irradiation point at the tip portion in the tip side portion of the proximal shaft of the sixth embodiment. FIG. 13 is a perspective view showing the shape of a tip portion of a proximal shaft of a seventh embodiment.

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 without departing from the spirit of the present invention. Furthermore, 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.

First Embodiment
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, a support catheter 1, and a guidewire 25 are mainly used. Each of the components used in PCI will be described below.

<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 described below. 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.

The Y-shaped connector 12 is provided at the base end of the guiding catheter body 11. The Y-shaped connector 12 has a main body portion 12a and a side arm 12b, and medicinal fluids and contrast media 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 body 11. The main body portion 12a has a base end opening 12c, and the balloon catheter 5 and support catheter 1 can be inserted through this base end opening 12c.

<Balloon Catheter>
The balloon catheter 5 is a treatment catheter. The balloon catheter 5 is a catheter for inserting into a stenotic portion 3 in a coronary artery to expand the stenotic portion 3. Any conventionally known balloon catheter can be appropriately used as the balloon catheter 5. For example, the balloon catheter 5 is 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 tube shape. The treatment catheter body 21 has a balloon 23 with a stent 24 mounted on its tip portion. Any conventionally known stent 24 can be appropriately used as the stent 24. The balloon catheter 5 is used together with a guidewire 25, a guiding catheter 4, and a support catheter 1.

<Support Catheter>
The support catheter 1 is advanced from the entrance of the coronary artery 2 to a position closer to the stenosis 3, and serves to guide the balloon 23 of the balloon catheter 5 to the stenosis 3. The support catheter 1 also serves to support the balloon 23 when inserting the balloon 23 into the stenosis 3. The support catheter 1 is inserted from the base end opening 4b of the guiding catheter 4, and has a length that allows it to protrude from the tip end opening 4a of the guiding catheter 4.

The detailed configuration of the support catheter 1 of this embodiment is described below. As shown in Figure 2, the support catheter 1 includes a protective member 32, a distal shaft 33, and a proximal shaft 34.

The distal shaft 33 is formed in a roughly cylindrical shape and is configured to allow the insertion of the balloon catheter 5. The distal shaft 33 constitutes the tip portion 1a of the support catheter 1. The distal shaft 33 is a roughly cylindrical member having a three-layer structure composed of, from the inside, an inner layer 35, a reinforcing layer 36, and an outer layer including a first constituent outer layer 37 and a second constituent outer layer 38.

The inner layer 35 of the distal shaft 33 is formed, for example, from polytetrafluoroethylene (PTFE) or tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA). The inner layer 35 is formed, for example, by applying PTFE to the outer surface of a silver-plated copper wire. In this case, the length of the inner layer 35 is adjusted so that the base end portion of the inner layer 35 protrudes (exposes) slightly from the base end portion of the reinforcing layer 36.

The reinforcing layer 36 of the distal shaft 33 is formed in a cylindrical mesh shape from a plurality of metal wires (strands) 36a, for example made of stainless steel, and is disposed between the inner layer 35 and the first and second constituent outer layers 37 and 38.

In this embodiment, for example, 16 metal wires 36a are used to form the reinforcing layer 36. 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 to form the reinforcing layer 36. In this case, the reinforcing layer 36 is formed so that the base end portion of the reinforcing layer 36 protrudes (exposes) from the base end portion of the first component outer layer 37. The number of wound metal wires 36a 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 adopted.

In this embodiment, the first constituent outer layer 37 and the second constituent outer layer 38 correspond to the outer layer of the distal shaft 33 (the same applies to each embodiment described later). That is, the outer layer of the distal shaft 33 is composed of the first constituent outer layer 37 and the second constituent outer layer 38. The base end side portion of the second constituent outer layer 38 may be formed into an obliquely cut shape, an arc shape, or a crescent shape. In this case, the base end side portion of the inner layer 35 is also formed into a similar shape. This makes it easier to insert the balloon catheter 5 into the distal shaft 33. In addition, since a base end side portion composed only of the inner layer 35 and the second constituent outer layer 38 is formed and the wall thickness of the base end side portion of the distal shaft 33 becomes thinner, the balloon catheter 5 can be easily inserted into the distal shaft 33 and the outer diameter can be reduced. Note that the number of constituent outer layers is two, but this is not limited to this, and it may be three or more.

The first outer layer 37 of the distal shaft 33 is formed of, for example, a nylon-based elastomer resin. The hardness of the first outer layer 37 is lower than the hardness of the second outer layer 38 described later.

The second outer layer 38 of the distal shaft 33 is arranged in contact with the first outer layer 37 along the axial direction of the distal shaft 33 and is formed in a roughly cylindrical shape. The second outer layer 38 covers the fixed portion after the tip portion of the proximal shaft 34 is fixed to the part of the distal shaft 33 inside the first outer layer 37 by a method described later. The second outer layer 38 is formed of, for example, polybutylene terephthalate. The hardness of the second outer layer 38 is higher than the hardness of the first outer layer 37.

The inner layer 35 and the first outer layer 37 may be made of the same material and are not limited to the materials described above. The inner layer 35 and the second outer layer 38 may be made of the same material and are not limited to the materials described above. The outer peripheral surfaces of the first outer layer 37 and the second outer layer 38 may be coated with a hydrophilic polymer containing polyurethane, polyvinylpyrrolidone (PVP), etc.

A tip tip 39 is integrally provided at the tip of the distal shaft 33. This tip tip 39 is made of polyamide elastomer mixed with, for example, bismuth oxide, a contrast agent, and is formed in a roughly cylindrical shape. The tip tip 39 is radiopaque, and a shadow appears under radioscopy.

Next, the proximal shaft 34 will be described. The proximal shaft 34 is a long wire made of, for example, stainless steel. The surface of the proximal shaft 34 is coated with, for example, PTFE.

A 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. The proximal shaft 34 constitutes the base end portion 1b of the support catheter 1. As shown in FIG. 4, the tip end portion 34a of the proximal shaft 34 is formed to be wider than the remaining portion. The tip end portion 34a is formed into a flat plate shape by pressing and crushing the tip portion of the proximal shaft 34, which is a wire, or by machining it. It is desirable that the width (length in the direction perpendicular to the axial direction) of the tip end portion 34a of the proximal shaft 34 is, for example, 8% or more of the circumferential length of the distal shaft 33. This increases the contact area of the tip end portion 34a with the distal shaft 33, making welding easier and strengthening the fixation of the proximal shaft 34 and the distal shaft 33. It is desirable that the thickness of the tip end portion 34a is equal to or less than the diameter of the wire of the proximal shaft 33.

In this embodiment, the distal portion 34a of the proximal shaft 34 is fixed to a portion of the distal shaft 33 that is more inward than the first constituent outer layer 37. Below, a method for fixing the distal portion 34a of the proximal shaft 34 to the distal shaft 33 will be described in detail.

3A, in the distal shaft 33, as described above, the base end portion of the reinforcing layer 36 protrudes from the base end portion of the first component outer layer 37, and the base end portion of the inner layer 35 protrudes from the base end portion of the reinforcing layer 36. In other words, the base end portion of the inner layer 35 protrudes from the base end portion of the first component outer layer 37. As described above, the tip end portion 34a of the proximal shaft 34 is fixed by welding to at least one metal wire 36a protruding from the base end portion of the first component outer layer 37. The welded portion is indicated by w1. As a result, the tip end portion 34a of the proximal shaft 34 is disposed between the inner layer 35 and the first component outer layer 37 of the distal shaft 33 when viewed in the axial direction. In other words, the tip end portion 34a of the proximal shaft 34 is fixed to a portion inside the first component outer layer 37 of the distal shaft 33. In this case, the proximal shaft 34 is disposed so that the width direction of the tip portion 34a coincides with the circumferential direction of the distal shaft 33. Although Fig. 3(a) shows a state in which one end of the single metal wire 36a constituting the reinforcing layer 36 and the tip portion 34a of the proximal shaft 34 are connected by welding, each end of the multiple metal wires 36a constituting the reinforcing layer 36 may be welded to the tip portion 34a of the proximal shaft 34.

3(b), the second outer layer 38 is provided so as to cover the tip portion 34a of the proximal shaft 34 and the welded portion w1 between the metal wire 36a of the reinforcing layer 36. In detail, with the tip portion 34a including the welded portion w1 of the proximal shaft 34 disposed in the lumen of the second outer layer 38, the inner circumferential surface of the second outer layer 38 and the outer circumferential surface of the inner layer 35 are welded, and the end face of the first outer layer 37 and the end face of the second outer layer 38 are welded. In this manner, the support catheter 1 is completed. Here, as shown in the figure, the tip portion 34a of the proximal shaft 34 and the distal shaft 33 are overlapped in the radial direction. In this case, it is desirable that the tip portion 34a of the proximal shaft 34 overlaps the distal shaft 33 by a distance (overlap distance) of 5 to 25% of the total length of the distal shaft 33. If the overlap distance is shorter than the above range, the connection strength of the distal portion 34a to the distal shaft 33 cannot be sufficiently improved, and if the overlap distance is longer than the above range, the overlap portion becomes hard and the passability may decrease. If the overlap distance is longer than the above range, the overlap portion having a substantially elliptical radial cross section increases in the axial direction, and the lumen occupancy rate of the distal shaft 33 in the guiding catheter 4 increases. Therefore, there is a risk that the passage resistance of the distal shaft 33 increases when a procedure is performed using a thinner guiding catheter 4. Furthermore, there is a risk that the insertion resistance of the guidewire increases when a procedure is performed using two guidewires. Therefore, it is desirable that the overlap distance is within the above range.

<How to use the support catheter>
A method of approaching from the radial artery in PCI will be described below with reference to FIG.

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 1a protrudes from the distal opening 4a. As a result, the distal portion 1a of the support catheter 1 is inserted into the coronary artery 2 and further reaches the stenosis portion 3.

After the distal end portion 1a of the support catheter 1 has been pushed into the stenosis 3 in this manner, the balloon catheter 5 is then inserted from the proximal opening 4b of the guiding catheter 4. The balloon catheter 5 has its tip inserted into the distal shaft 33, and is then pushed forward until it protrudes from the tip of the distal shaft 33. By pushing it forward in this manner, the distal end 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.

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 then further beyond the entrance 2a, the support catheter 1 guides it to the stenosis 3. In addition, 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, expanding the stenosis 3. This allows blood flow to be restored at the stenosis 3.

As described above, according to the support catheter 1 of this embodiment, the tip portion 34a of the proximal shaft 34 is welded to the metal wire 36a of the reinforcing layer 36. As a result, the tip portion 34a of the proximal shaft 34 is fixed between the inner layer 35 and the first constituent outer layer 37 of the distal shaft 33. In other words, the tip portion 34a of the proximal shaft 34 is fixed to a portion inside the first constituent outer layer 37 of the distal shaft 33. With this configuration, it is possible to make the outermost diameter (length in the direction perpendicular to the axial direction) of the support catheter 1 smaller than in the conventional case without reducing the inner diameter of the distal shaft 33. In addition, since the tip portion 34a of the proximal shaft 34 is formed wide, the tip portion 34a can be welded to the metal wire 36a of the reinforcing layer 36 with a wide contact area. This increases the connection strength of the welded portion w1, making it difficult for the tip portion 34a of the proximal shaft 34 to come off the metal wire 36a. In other words, the tip portion 34 a of the proximal shaft 34 becomes less likely to come off the distal shaft 33 .

In this embodiment, the tip portion 34a of the proximal shaft 34, which is made of stainless steel, is welded to the metal wire 36a, which is also made of stainless steel. This makes it easier to weld the tip portion 34a and the metal wire 36a together and improves the weld strength.

In this embodiment, the second outer layer 38 includes the distal end portion 34a including the welded portion w1 of the proximal shaft 34 and has a higher hardness than the first outer layer 37. This makes it possible to strengthen the connection between the distal end portion 34a of the proximal shaft 34 including the welded portion w1 and the metal wire 36a, and ensures the flexibility of the distal end of the distal shaft 33, allowing the support catheter 1 to be smoothly pushed through the guiding catheter 4 and blood vessels. In addition, the hardness of the distal shaft 33 can be changed in stages from the base end portion to the distal end portion, thereby avoiding kinking due to a sudden change in hardness.

In addition, in this embodiment, since the tip portion 34a of the proximal shaft 34 is not exposed from the distal shaft 33, the number of liquid-contacting members (liquid-contacting portions) can be reduced compared to the conventional embodiment in which the connection portion between the distal shaft and the proximal shaft is exposed without being covered. This allows a wider range of materials to be used for the proximal shaft 34 (tip portion 34a), and a wider range of connection methods for the tip portion 34a. For example, the tip portion 34a can be connected with an adhesive, and even if the material is denatured by welding when the tip portion 34a is connected, a decrease in safety can be suppressed. Furthermore, as a further effect of the tip portion 34a of the proximal shaft 34 not being exposed from the distal shaft 33, unevenness that may occur around the welded portion w1 and the tip portion 34a can be suppressed by covering it with the inner layer 35 and the second component outer layer 38, making the surface of the support catheter 1 smooth. This makes it possible to prevent or suppress burrs and the like, thereby reducing the impact on the human body, and also allows the balloon catheter 5, which is a treatment catheter, to be smoothly inserted into the distal shaft 33.

Furthermore, in this embodiment, the first constituent outer layer 37 and the second constituent outer layer 38 are formed from the same material, making it easier to weld the first constituent outer layer 37 and the second constituent outer layer 38 together.

Second Embodiment
Next, a second embodiment of the method for fixing the proximal shaft 34 to the distal shaft 33 will be described. In the second embodiment, the same components as those in the first embodiment described above are given the same reference numerals, and the description thereof may be omitted.

5A, in the distal shaft 33 of the second embodiment, at least one metal wire 36a protruding from the base end portion of the first component outer layer 37 and at least one metal wire 36a wound in a direction different from the winding direction of the metal wire 36a protruding from the base end portion of the first component outer layer 37 are welded with a radiopaque marker 40 formed, for example, in an annular (O-ring) shape. The radiopaque marker 40 is disposed at the base end end of the inner layer 35 so that its axial direction is parallel to the axial directions of the distal shaft 33 and the proximal shaft 34. The welded portion between the metal wire 36a wound in one direction and the radiopaque marker 40 (one end surface of the radiopaque marker 40) is illustrated as w1, and the welded portion between the metal wire 36a wound in the other direction and the radiopaque marker 40 (one end surface of the radiopaque marker 40) is illustrated as w2. The contrast marker 40 is made of a metal such as stainless steel or platinum.

In this embodiment, the distal end 34c of the proximal shaft 34 is formed to be wide, similar to the distal end portion 34a of the proximal shaft 34 in the first embodiment described above. The combination of the distal end 34c of the proximal shaft 34 and the contrast marker 40 constitutes the distal end portion 34b of the proximal shaft 34.

Next, the tip 34c of the proximal shaft 34 is welded to the contrast marker 40 in a state where it is inserted into the contrast marker 40 from the other end side of the contrast marker 40 welded to the multiple metal wires 36a. This forms the tip portion 34b of the proximal shaft 34. The welded portion between the contrast marker 40 and the tip portion 34c of the proximal shaft 34 is illustrated as w3. Note that, for the sake of simplicity of the drawings, only one welded portion w3 between the contrast marker 40 and the tip portion 34c of the proximal shaft 34 is illustrated, but in this embodiment, there are multiple welded portions between the contrast marker 40 and the tip portion 34c. In addition, since the wide tip portion 34b of the proximal shaft 34 is formed by welding the tip portion 34c of the proximal shaft 34 to the contrast marker 40, the tip portion 34c does not necessarily have to be flat in the second embodiment. Furthermore, although the tip 34c of the proximal shaft 34 is inserted into the inside of the contrast marker 40 welded to the metal wire 36a and welded, this is not limited to this. For example, the tip 34c may be placed on the outer peripheral surface of the contrast marker 40 and welded thereto, or a hole that penetrates axially through the annular portion of the contrast marker 40 may be provided and the tip 34c of the proximal shaft 34 may be inserted into the hole and welded thereto. It is also possible to weld the tip 34c of the proximal shaft 34 to the contrast marker 40 to form the tip portion 34b of the proximal shaft 34, and then weld the tip portion 34b to the metal wire 36a.

Next, as shown in FIG. 5(b), the second component outer layer 38 is provided to cover the welded portions w1 and w2 between the metal wire 36a and the contrast marker 40, and the welded portion w3 between the contrast marker 40 and the tip portion 34c of the proximal shaft 34, and the tip portion 34c. In detail, in a state where the tip portion 34b including the welded portion w3 in the proximal shaft 34 is disposed in the inner cavity of the second component outer layer 38 (where the welded portions w1 and w2 are both disposed in the inner cavity of the second component outer layer 38), the inner surface of the second component outer layer 38 is welded to the outer surface of the inner layer 35, and the end face of the first component outer layer 37 is welded to the end face of the second component outer layer 38. In this manner, the support catheter 1A is completed. The overlap distance of the tip portion 34b of the proximal shaft 34 with respect to the distal shaft 33 and its effect are the same as those in the first embodiment described above.

As described above, according to the support catheter 1A of the second embodiment, as in the first embodiment, it is possible to make the outermost diameter of the support catheter 1A smaller than before without reducing the inner diameter of the distal shaft 33. In addition, since the welded portion of the tip portion 34b of the proximal shaft 34 is increased compared to the first embodiment, the connection strength of the tip portion 34b of the proximal shaft 34 can be improved. This makes it more difficult for the tip portion 34b of the proximal shaft 34 to come off the distal shaft 33.

In addition, in this embodiment, multiple (many) metal wires 36a can be welded to the annular contrast marker 41, which has a large weldable area, thereby improving the connection strength between the distal shaft 33 and the contrast marker 40.

In addition, in this embodiment, the provision of the contrast marker 40 allows the shadow of the distal end portion 34b of the proximal shaft 34 to be revealed under radioscopy. This allows the passage of the distal end portion 34b of the proximal shaft 34 through the guiding catheter 4 to be easily recognized, and serves as a marker for the base end opening of the distal shaft 33 when inserting a treatment catheter into the distal shaft 33.

In addition, in this embodiment, the effect of the tip portion 34b of the proximal shaft 34 not being exposed from the distal shaft 33 is the same as in the first embodiment.

Third Embodiment
Next, a third embodiment of the method for fixing the proximal shaft 34 to the distal shaft 33 will be described. In the third embodiment, the same components as those in the first embodiment described above are given the same reference numerals, and the description thereof may be omitted.

6(a), in the distal shaft 33 of the third embodiment, at least one metal wire 36a protruding from the base end portion of the first component outer layer 37 and at least one metal wire 36a wound in a direction different from the winding direction of the metal wire 36a protruding from the base end portion of the first component outer layer 37 are welded to a contrast marker 41 formed, for example, in a C-ring shape with a part of the ring portion cut out. The contrast marker 41 is disposed on the base end surface of the inner layer 35 so that its axial direction is parallel to the axial directions of the distal shaft 33 and the proximal shaft 34. The welded portion between the metal wire 36a wound in one direction and the contrast marker 41 (one end surface of the contrast marker 41) is illustrated as w1, and the welded portion between the metal wire 36a wound in the other direction and the contrast marker 41 (one end surface of the contrast marker 41) is illustrated as w2. The contrast marker 41, like the contrast marker 40, is made of a metal such as stainless steel or platinum.

In this embodiment, the distal end 34c of the proximal shaft 34 is formed to be wide, similar to the distal end portion 34a of the proximal shaft 34 in the first embodiment described above. The combination of the distal end 34c of the proximal shaft 34 and the contrast marker 41 constitutes the distal end portion 34b of the proximal shaft 34.

Next, the tip 34c of the proximal shaft 34 is welded to the contrast marker 41 in a state where it is inserted (or fitted) into the notch of the contrast marker 41 from the other end face side of the contrast marker 41 welded to the metal wire 36a. This forms the tip portion 34b of the proximal shaft 34. The welded portion between the contrast marker 41 and the tip portion 34c of the proximal shaft 34 is illustrated as w4. Note that, for the sake of simplicity of the drawing, only two welded portions w4 between the contrast marker 41 and the tip portion 34c of the proximal shaft 34 are illustrated, but in this embodiment, there are two or more welded portions between the contrast marker 41 and the tip portion 34c. Note that, since the wide tip portion 34b of the proximal shaft 34 is formed by welding the tip portion 34c of the proximal shaft 34 to the contrast marker 41, the tip portion 34c does not necessarily have to be flat in the third embodiment. In addition, the tip portion 34c of the proximal shaft 34 is inserted (or fitted) into the cutout portion of the contrast marker 41 welded to the metal wire 36a and welded, but this is not limited to this. It is also possible to weld the tip portion 34c of the proximal shaft 34 to the contrast marker 41 to form the tip portion 34b of the proximal shaft 34, and then weld the tip portion 34b to the metal wire 36a.

6(b), the second outer layer 38 is provided to cover the welded portions w1 and w2 between the metal wire 36a and the radiopaque marker 41, and the welded portion w4 between the radiopaque marker 41 and the tip portion 34c of the proximal shaft 34, and the tip portion 34c. In detail, in a state where the tip portion 34b including the welded portion w4 in the proximal shaft 34 is disposed in the inner cavity of the second outer layer 38 (where the welded portions w1 and w2 are both disposed in the inner cavity of the second outer layer 38), the inner surface of the second outer layer 38 is welded to the outer surface of the inner layer 35, and the end face of the first outer layer 37 is welded to the end face of the second outer layer 38. In this manner, the support catheter 1B is completed. The overlap distance of the tip portion 34b of the proximal shaft 34 with respect to the distal shaft 33 and its effect are the same as those in the first embodiment described above.

As described above, according to the support catheter 1B of the third embodiment, as in the first embodiment, it is possible to make the outermost diameter of the support catheter 1B smaller than before without reducing the inner diameter of the distal shaft 33. In addition, since the welded portion of the tip portion 34b of the proximal shaft 34 is increased compared to the first embodiment, the connection strength of the tip portion 34b of the proximal shaft 34 can be improved. This makes it more difficult for the tip portion 34b of the proximal shaft 34 to come off the distal shaft 33.

In particular, since the tip 34c of the proximal shaft 34 is welded while being inserted (or fitted) into the cutout portion of the radiographic marker 41, the weld length between the radiographic marker 41 and the tip 34c of the proximal shaft 34 can be increased and welding can be performed via two opposing surfaces in the cutout portion of the radiographic marker 41, improving the connection strength between the radiographic marker 41 and the tip 34c of the proximal shaft 34. In addition, since the tip 34c of the proximal shaft 34 can be positioned to match the cutout portion of the radiographic marker 41 and welded, the positioning of the proximal shaft 34 is facilitated.

In addition, in this embodiment, the provision of the contrast marker 41 allows the shadow of the distal end portion 34b of the proximal shaft 34 to be revealed under radioscopy. This allows the passage of the distal end portion 34b of the proximal shaft 34 through the guiding catheter 4 to be easily recognized, and serves as a marker for the base end opening of the distal shaft 33 when inserting a treatment catheter into the distal shaft 33.

In addition, in this embodiment, the effect of the tip portion 34b of the proximal shaft 34 not being exposed from the distal shaft 33 is the same as in the first embodiment.

Fourth Embodiment
Next, a fourth embodiment of the method for fixing the proximal shaft 34 to the distal shaft 33 will be described. In the fourth embodiment, the same components as those in the first embodiment described above are given the same reference numerals, and the description thereof may be omitted.

7(a), in the distal shaft 33 of the fourth embodiment, the inner layer 35 is formed by applying, for example, PTFE to the outer surface of, for example, a silver-plated copper wire 50. In this case, the inner layer 35 is formed so that the base end portion and the tip end portion of the inner layer 35 protrude (expose) from the base end portion and the tip end portion of the reinforcing layer 36, respectively. Then, the reinforcing layer 36 is provided in a predetermined axial region of the inner layer 36 in the same manner as in the first embodiment described above.

7(b), the distal end portion of the inner layer 35 is covered with a cylindrical distal tip 39, and the area where the reinforcing layer 36 is provided is covered with the first component outer layer 37. The distal end portion of the second component outer layer 38 is welded to the base end portion of the first component outer layer 37 (end-to-end welding) and the inner surface of the second component outer layer 38 is welded to the outer surface of the inner layer 35 with the distal end portion 34a of the proximal shaft 34 sandwiched between the inner surface of the second component outer layer 38 and the outer surface of the inner layer 35. As a result, the distal end portion 34a of the proximal shaft 34 is fixed between the inner layer 35 of the distal shaft 33 and the second component outer layer 38. In other words, the distal end portion 34a of the proximal shaft 34 is fixed to the inner portion of the distal shaft 33 relative to the second component outer layer 38. In Fig. 7(b), the tip portion 34a of the proximal shaft 34 is kept within the second component outer layer 38, but the present invention is not limited thereto, and the tip portion 34a may be extended into the first component outer layer 37, or the tip portion 34a thus extended may be folded into the reinforcing layer 36. In this case, the tip portion 34a can be present in the entire axial region of the second component outer layer 38 within the second component outer layer 38, so that it is possible to improve the strength of the entire axial region of the second component outer layer 38. Also, an adhesive may be applied to the tip portion 34a of the proximal shaft 34, and then the tip portion 34a may be sandwiched between the inner circumferential surface of the second component outer layer 38 and the outer circumferential surface of the inner layer 35.

Next, as shown in Figure 7(c), the copper wire 50 is stretched and pulled out. In this manner, the support catheter 1C is completed. Note that the overlap distance of the tip portion 34a of the proximal shaft 34 with respect to the distal shaft 33 and its effect are the same as those of the first embodiment described above.

As described above, according to the support catheter 1C of the fourth embodiment, as in the first embodiment, it is possible to make the outermost diameter of the support catheter 1C smaller than before without reducing the inner diameter of the distal shaft 33. Moreover, since the end face of the tip side portion of the second component outer layer 38 and the end face of the base side portion of the first component outer layer 37 are joined and welded, there is no increase in the outer diameter during welding.

In addition, in this embodiment, as in the first embodiment described above, the distal end portion 34a of the proximal shaft 34 is formed to be wide, so that the distal end portion 34a can be welded in a state in which it is in contact with the inner layer 35 and the second constituent outer layer 38 over a wide area. This makes it difficult for the distal end portion 34a of the proximal shaft 34 to come off the distal shaft 33.

In addition, in this embodiment, the tip portion 34a of the proximal shaft 34 is sandwiched between the inner layer 35 of the distal shaft 33 and the second constituent outer layer 38, thereby improving the connection strength of the tip portion 34a of the proximal shaft 34 to the distal shaft 33.

In addition, in this embodiment, since the tip portion 34a of the proximal shaft 34 is not exposed from the distal shaft 33, the number of liquid-contacting members (liquid-contacting parts) can be reduced compared to the conventional embodiment in which the connection portion between the distal shaft and the proximal shaft is exposed without being covered. This allows a wider range of materials to be used for the proximal shaft 34 (tip portion 34a), and a wider range of connection methods for the tip portion 34a. For example, the tip portion 34a can be connected with an adhesive, and even if the material is denatured by welding when the tip portion 34a is connected, a decrease in safety can be suppressed. Furthermore, as a further effect of the tip portion 34a of the proximal shaft 34 not being exposed from the distal shaft 33, the unevenness of the second component outer layer 38 around the tip portion 34a can be suppressed to give a smooth surface. This prevents or suppresses burrs, etc., thereby reducing the impact on the human body, and also allows the balloon catheter 5, which is a treatment catheter, to be smoothly inserted into the distal shaft 33.

Furthermore, in this embodiment, unlike the embodiment shown in FIG. 8 described later, the inner circumferential surface of the second outer layer 38 and the outer circumferential surface of the inner layer 35 are welded together in a state in which the distal portion 34a of the proximal shaft 34 and the reinforcing layer 36 do not overlap in the radial direction. In this case, compared to the embodiment in which the distal portion 34a of the proximal shaft 34 and the reinforcing layer 36 overlap in the radial direction, the radial cross-sectional outer shape of the distal shaft 33 is not elliptical but is close to a perfect circle, making it easier to pass the second guide wire when performing a procedure using two guide wires. In addition, since the distal portion 34a and the reinforcing layer 36 do not overlap in the radial direction, it is possible to make the wall thickness of the distal shaft constant along the axial direction, and the maximum inner diameter can be secured for a constant outer diameter. Furthermore, it is possible to suppress the protrusion of the distal portion 34a of the proximal shaft 34 from the first outer layer 37 and the second outer layer 38 of the distal shaft 33.

Fifth Embodiment
The tip end portion of the proximal shaft 34 may be formed as follows. As shown in FIG. 9(a), an upper die 110 and a lower die 112 are prepared, which are configured to be able to reciprocate in the vertical direction. An inclined portion 111 is fixed to one side (left side of the figure) of the inner surface of the upper die 110, and an inclined portion 113 is fixed to one side (left side of the figure) of the inner surface of the lower die 112. In the figure, the inclined portion 111 is inclined upward to the right, and the inclined portion 113 is inclined downward to the right. One end of the proximal shaft 34, which is a flat wire, is disposed between the upper die 110 and the lower die 112, and the upper die 110 and the lower die 112 are moved in directions approaching each other to press the proximal shaft 34. As a result, as shown in FIG. 9(b), a proximal shaft 34A having a tip end portion 34A2 having a triangular (tapered) tip end portion 34A1 in a side view can be obtained. By fixing the tip portion 34A1 of the proximal shaft 34A to the metal wire 36a by welding, the outer corners of the tip portion 34A1 can be eliminated. This makes it possible to suppress or prevent the tip portion 34A1 from getting caught on the outer layer when the tip portion 34A1 is covered with the outer layer. The tip portion 34A1 may be formed horizontally by eliminating the inclined portion on the upper side as shown in FIG. 9(b). In this case, the inclined portion 111 of the upper mold 110 in FIG. 9(a) is removed, and the upper mold 110 is made into a fixed mold.

Sixth Embodiment
Another example of a method for eliminating the corners of the outer shape of the tip portion of the proximal shaft is as follows. As shown in Fig. 10, the tip portion 34a1 of the tip side portion 34a of the proximal shaft 34, which is a flat wire, is irradiated with a laser (for example, three laser irradiation points w10) to eliminate the corners of the tip portion 34a1. This makes it possible to suppress or prevent the tip portion 34A1 from getting caught on the outer layer when the tip portion 34a1 is covered with the outer layer. Note that the number of laser irradiation points w10 is not limited to three, and may be less than three or more than three.

Seventh Embodiment
The distal portion of the proximal shaft may be formed as follows. As shown in Fig. 11, the distal portion 34B1 of the proximal shaft 34B may be an arc piece that is arc-shaped when viewed from the axial direction. This makes it easier to bring the distal portion 34B1 into contact with the curved surface of the inner layer 35 of the distal shaft 33, making it easier to weld the distal portion 34B1 and strengthening the fixation between the proximal shaft 34 and the distal shaft 33.

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.

In each of the above embodiments, the tip portions 34a, 34b of the proximal shaft 34 are formed in a flat plate shape, an O-ring shape, or a C-ring shape, but are not limited to this. The tip portions 34a, 34b of the proximal shaft 34 are formed to be wider than the remaining portions and may have any shape that allows them to be positioned between the inner layer 35 and the outer layer.

In addition, in each of the above embodiments, the tip portion 34a of the proximal shaft 34 and the contrast markers 40, 41 are fixed to the metal wire 36a by welding, and the tip portion 34c of the proximal shaft 34 is fixed to the contrast markers 40, 41 by welding, but this is not limited to the above and the fixation may be performed, for example, by adhesive or the like.

In addition, in each of the above embodiments, the tip portion 34a of the proximal shaft 34 is configured to be fixed between the inner layer 35 and the first constituent outer layer 37 of the distal shaft 33, but this is not limited to this, and the fixing location of the tip portion 34a of the proximal shaft 34 may be any portion that is inner than the first constituent outer layer 37 of the distal shaft 33.

In addition, in each of the above embodiments, the second outer layer 38 and the first outer layer 37 are formed from materials having the same composition, but this is not limited thereto, and the second outer layer 38 and the first outer layer 37 may be formed from materials having different compositions. This makes it possible to gradually change the physical properties, such as flexibility, of the distal shaft 33 in the axial direction.

In the fourth embodiment, the tip portion 34a of the proximal shaft 34 is arranged to be confined to the area of the inner surface of the second outer layer 38, but this is not limited thereto. As shown in FIG. 8, the tip portion 34a of the proximal shaft 34 may extend to the area of the inner surface of the first outer layer 37. In this case, the tip portion 34a of the proximal shaft 34 is not only sandwiched between the inner surface of the second outer layer 38 and the outer surface of the inner layer 35, but also between the inner surface of the first outer layer 37 and the outer surface of the inner layer 35, so that the connection strength of the tip portion 34a of the proximal shaft 34 is further improved. Furthermore, according to the above configuration, it is possible to eliminate the flexible portion composed only of the inner layer 35 and the outer layer, so that kinking in that portion can be prevented. Alternatively, the reinforcing layer 36 may be extended to the base end portion of the distal shaft 33, and the base end portion of the reinforcing layer 36 and the tip end portion 34a of the proximal shaft 34 may be covered with the second outer layer 38. Even in this case, kinking due to a sudden change in hardness can be avoided, and the hardness of the distal shaft 33 can be adjusted by the length of the extending reinforcing layer 36.

Furthermore, in each of the above embodiments, the first component outer layer 37 may be welded before the second component outer layer 38 is welded, but it is also possible to weld the first component outer layer 37 except for the base end portion first, and then weld the base end portion together with the second component outer layer 38. This is to prevent the connection points between the first component outer layer 37 and the second component outer layer 38 from overlapping and becoming thick, or to prevent the two from separating and creating gaps.

1, 1A, 1B, 1C Support catheter 4 Guiding catheter 4a Distal opening of guiding catheter 4b Base opening of guiding catheter 5 Balloon catheter 33 Distal shaft 34, 34A, 34B Proximal shaft 34a, 34b, 34A2, 34B1 Distal portion of proximal shaft 35 Inner layer 36 Reinforcing layer 36a Metal wire 37 First constituent outer layer (outer layer)
38 Second constituent outer layer (outer layer)
40, 41 Contrast marker

Claims (5)

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 comprising an inner layer, a reinforcing layer and an outer layer;
a proximal shaft having a tip portion disposed on a portion of the distal shaft that is more inside than the outer layer,
the distal end portion of the proximal shaft is formed to be wider than the remaining portion, includes a contrast marker , and is sandwiched only between the inner layer and the outer layer of the distal shaft;
The outer layer of the distal shaft includes a first constituent outer layer and a second constituent outer layer arranged adjacent to each other along an axial direction of the distal shaft,
an end surface of the first outer layer and an end surface of the second outer layer are welded to each other;
The first outer layer may or may not encapsulate a distal end portion of the proximal shaft,
A support catheter, wherein the second outer layer encloses a distal end portion of the proximal shaft and has a harder hardness than the first outer layer . The reinforcing layer of the distal shaft is formed of a plurality of metal wires in a cylindrical mesh shape,
The support catheter of claim 1 , wherein the distal portion of the proximal shaft is fixed to at least one of the plurality of metal wires. The support catheter according to claim 1 or 2, wherein the distal end portion of the proximal shaft is formed in a ring shape whose axial direction is aligned with the axial direction of the proximal shaft. The support catheter according to claim 1 or 2, wherein the distal end portion of the proximal shaft is formed in a C-ring shape with its axis aligned along the axis of the proximal shaft and with a portion of the ring cut out. The support catheter according to any one of claims 2 to 4, wherein the metal wire and the proximal shaft are made of stainless steel.

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