Catheter system

Abstract

To provide a catheter system for facilitating percutaneous procedures under an artificial valve detention environment.SOLUTION: A catheter system includes: a first catheter having a first curved part of a curved shape provided at the tip part, and a first lumen provided inside; and a second catheter having a second curved part of a curved shape provided at the tip part and rigidity that satisfies the undermentioned formula (1), which is arranged slidably in a longitudinal direction inside the first lumen. (1) 0.6≤(rigidity of second catheter) / (rigidity of first catheter)≤1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a catheter system.

Background Art

[0002] Medical devices used in percutaneous coronary intervention are known. For example, Patent Document 1 discloses a catheter introduction system including a dilator, a core, and a sheath. For example, Patent Documents 2 and 3 disclose coronary catheters for delivering a medical device for treatment to the coronary artery. The coronary catheter is also called a guiding catheter. Percutaneous coronary intervention is also called PCI.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a minimally invasive treatment method for aortic valve stenosis, transcatheter aortic valve implantation is known. Transcatheter aortic valve implantation is also called TAVI. In TAVI, the aortic valve with reduced function is replaced with an artificial valve. Therefore, in patients after TAVI surgery, an artificial valve is implanted in the aorta, and the entrance of the coronary artery is covered by the artificial valve. For this reason, when performing PCI procedures on patients after TAVI artificial valve implantation, the artificial valve becomes an obstacle, making it difficult to place a guiding catheter at the entrance of the target coronary artery. As a result, problems such as difficulties in the procedure, longer procedure time, increased use of contrast agent, increased radiation exposure, and inability to perform the procedure due to inability to access the coronary artery and resulting in death may occur. The techniques described in Patent Documents 1 to 3 do not consider such problems at all. Such problems are common to both cases where a self-expanding biological valve is used as the artificial valve and cases where a balloon-expandable biological valve is used as the artificial valve. In particular, since the self-expanding biological valve is longer in the longitudinal direction compared to the balloon-expandable biological valve, the above problems are more prominent. Such problems are common not only to PCI but also to percutaneous procedures in general for patients after artificial valve implantation.

[0005] The present disclosure has been made to solve at least a part of the above-described problems, and an object thereof is to provide a catheter system for facilitating percutaneous procedures in an artificial valve implantation environment.

Means for Solving the Problems

[0006] The present disclosure has been made to solve at least a part of the above-described problems and can be realized in the following forms.

[0007] (1) According to one embodiment of the present disclosure, a catheter system is provided. The catheter system includes a first catheter having a curved first bending portion provided at a distal end and a first lumen provided inside, a curved second bending portion provided at a distal end, and a rigidity satisfying the following formula (1), and a second catheter slidably disposed longitudinally inside the first lumen. 0.6 ≦ (rigidity of the second catheter) / (rigidity of the first catheter) ≦ 1 ···(1)

[0008] According to this configuration, by inserting the second catheter having the second curved portion inside the first catheter having the first curved portion, the two curved portions are realized by two catheters. Therefore, compared with the case where the two curved portions are realized by a single catheter, it is possible to suppress the springing of the distal end portion of the catheter accompanying the rotation operation, and fine operations such as rotating only the distal end portion of the second catheter become possible. Since the second catheter is disposed inside the first catheter, the outer diameter of the second catheter is smaller than the outer diameter of the first catheter. Therefore, after delivering the distal end portion of the catheter system to the vicinity of the artificial valve, the distal end portion of the second catheter is protruded from the distal end of the first catheter, and by using the distal end portion of the relatively thin-diameter second catheter, the strut gap of the artificial valve can be smoothly passed through. Since the rigidity of the second catheter satisfies the formula (1), the flexibility and torque transmission property of the first catheter in the state where the second catheter is inserted can be maintained. Therefore, the operator can smoothly deliver the first catheter with the second catheter inserted thereto to the vicinity of the artificial valve. Since the rigidity of the second catheter satisfies the formula (1), the second catheter can be made difficult to buckle. Therefore, when the second catheter is pushed forward within the first catheter, it is possible to suppress the occurrence of buckling in the second catheter. Since the rigidity of the second catheter satisfies the formula (1), the torque transmission property of the second catheter can be improved. Therefore, after the operator protrudes the distal end portion of the second catheter from the distal end of the first catheter, by applying a rotation operation to the second catheter, an operation of passing the distal end portion of the second catheter through the strut gap of the artificial valve or selection of a target coronary artery in PCI can be facilitated. As a result, according to the catheter system of this configuration, percutaneous procedures in an artificial valve implantation environment can be facilitated.

[0009] (2) In the catheter system of the above-described embodiment, the second catheter may have a rigidity that satisfies the following formula (2). 0.6 ≦ (rigidity of the proximal side of the second curved portion of the second catheter) / (rigidity of the first curved portion of the first catheter) ≦ 1 ··· (2)

[0010] (3) In the catheter system of the above-described embodiment, the second catheter may further have a curved third curved portion provided on the distal end side of the second curved portion. According to this configuration, since the second catheter has the third curved portion provided on the distal end side of the second curved portion, a more complex movement can be caused by the distal end portion of the second catheter as compared with the configuration having only the second curved portion.

[0011] (4) In the catheter system of the above-described embodiment, the second catheter may further have a straight first straight portion provided on the proximal end side of the second curved portion and a straight second straight portion provided on the distal end side of the second curved portion and on the proximal end side of the third curved portion.

[0012] (5) In the catheter system of the above-described embodiment, when the second catheter in a state where the direction from the proximal end side to the distal end side of the second straight portion is aligned with the direction from the lower side to the upper side in the vertical direction is viewed from the direction from the proximal end side to the distal end side of the first straight portion, the portion on the distal end side of the third curved portion may be located on a virtual plane parallel to both the first straight portion and the second straight portion. According to this configuration, the second catheter can be configured to be suitable for an approach to the left coronary artery in percutaneous coronary intervention.

[0013] (6) In the catheter system of the above-described embodiment, when the second catheter in a state where the direction from the proximal end side to the distal end side of the second straight portion is aligned with the direction from the lower side to the upper side in the vertical direction is viewed from the direction from the proximal end side to the distal end side of the first straight portion, the portion on the distal end side of the third curved portion may be located on the left side of a virtual plane parallel to both the first straight portion and the second straight portion. According to this configuration, the second catheter can be configured to be suitable for an approach to the left coronary artery in percutaneous coronary intervention.

[0014] (7) In the catheter system of the above-described embodiment, when the second catheter in a state where the direction from the proximal end side to the distal end side of the second straight portion is aligned with the direction from the lower side to the upper side in the vertical direction is viewed from the direction from the proximal end side to the distal end side of the first straight portion, the portion on the distal end side of the third bending portion may be located on the right side of a virtual plane parallel to both the first straight portion and the second straight portion. According to this configuration, the second catheter can be configured to be suitable for an approach to the right coronary artery in percutaneous coronary intervention.

[0015] (8) In the catheter system of the above-described embodiment, when the proximal end portion of the second catheter is rotationally operated in the circumferential direction with the distal end portion of the second catheter protruding from the distal end of the first catheter, the rotation center of the distal end portion of the second catheter may be located on a straight line connecting the distal end of the first catheter and the second bending portion. According to this configuration, while maintaining the position of the first catheter, only the distal end portion of the second catheter, which is on the distal end side of the distal end of the first catheter, can be rotated. Therefore, it is possible to suppress the movement of the first catheter accompanying the rotational operation of the second catheter and the interference of the first catheter with the artificial valve. Since a fine operation such as rotating only the distal end portion of the second catheter becomes possible, it is possible to easily pass through the gap between the struts of the artificial valve, and in the case of PCI, it is possible to easily select the target coronary artery with the distal end portion of the second catheter.

[0016] The present disclosure can be realized in various aspects, for example, in the form of a catheter system, a catheter used in the catheter system, a medical tube for a catheter, and a manufacturing method thereof.

Brief Description of the Drawings

[0017]

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Mode for Carrying Out the Invention

[0018] <First Embodiment> FIG. 1 is an explanatory diagram illustrating the configuration of a catheter system 1000. The catheter system 1000 is an introduction system used when inserting a therapeutic medical device into a coronary artery in percutaneous coronary intervention. Percutaneous coronary intervention is also called PCI. The therapeutic medical device can be a combination of various devices such as a catheter, a microcatheter, and a through-wire, depending on the location of the lesion and the purpose of the procedure. Hereinafter, the case of applying the catheter system 1000 to PCI for a coronary artery will be illustrated and described. The catheter system 1000 can be used not only for PCI but also for percutaneous procedures in general. The catheter system 1000 includes a first catheter 1 and a second catheter 2.

[0019] In FIG. 1, for convenience of explanation, it includes parts where the relative ratio of the sizes of each component member is different from the actual situation. In FIG. 1, it includes parts where a part of each component member is exaggerated. FIG. 1 shows XYZ axes orthogonal to each other. The X-axis corresponds to the longitudinal direction of the first catheter 1 and the second catheter 2. The X-axis corresponds to the axial direction of the first catheter 1 and the second catheter 2. The Y-axis corresponds to the width direction of the first catheter 1 and the second catheter 2. The Z-axis corresponds to the height direction of the first catheter 1 and the second catheter 2. The left side (-X-axis direction) of FIG. 1 is called the "tip side" of the first catheter 1 and the second catheter 2, and the right side (+X-axis direction) of FIG. 1 is called the "proximal end side" of the first catheter 1 and the second catheter 2. In FIG. 1, one end located on the tip side among both ends in the longitudinal direction (X-axis direction) of the first catheter 1 and the second catheter 2 is called the "tip", and the other end located on the proximal end side is called the "proximal end". In FIG. 1, the tip and its vicinity are called the "tip portion", and the proximal end and its vicinity are called the "proximal end portion". The tip side is inserted into the living body, and the proximal end side is operated by an operator such as a doctor. These points are also common in FIGS. 2 and later.

[0020] FIG. 2 is a longitudinal sectional view of a part OP of the first catheter 1. As shown in FIG. 1, the first catheter 1 includes a tube 10, a tip 110, and a connector 120. The tube 10 is a hollow tubular body having an elongated outer shape. As shown in FIG. 2, the tube 10 has a main body portion 101, a mesh assembly 102, and a liner 103. The main body portion 101 is a tube formed of a resin material. The main body portion 101 can be formed of at least any one of, for example, polyamide, polyamide elastomer, polyester, polyurethane, and polyurethane elastomer. The mesh assembly 102 is a mesh member formed by weaving flat wires in a mesh pattern. The mesh assembly 102 can be formed of at least any one of a stainless alloy, a superelastic alloy, and a hard resin material. Examples of the stainless alloy include SUS304. Examples of the superelastic alloy include nickel titanium and nickel titanium alloy. Examples of the hard resin material include reinforced plastics such as PEEK. As shown in FIG. 2, the mesh assembly 102 is embedded inside the main body portion 101 and reinforces the main body portion 101. Instead of the mesh assembly 102, the main body portion 101 may be reinforced using a coil. The liner 103 is a tube formed of a resin material. The liner 103 is disposed inside the main body portion 101 and the mesh assembly 102. The liner 103 can be formed of, for example, a fluororesin such as PTFE. When the liner 103 is provided, the mesh assembly 102 may be disposed on the outer peripheral surface of the liner 103. The liner 103 may be omitted. The inner cavity of the liner 103 is also referred to as the first lumen 1L. The second catheter 2 is inserted into the first lumen 1L.

[0021] FIG. 3 is an enlarged view of the tip side of the first catheter 1 and the second catheter 2 of the catheter system 1000. As shown in FIG. 1, the tube 10 has a proximal straight portion 11, a first curved portion 12, and a distal straight portion 13 from the proximal side toward the distal side. In FIG. 1, the axis passing through the centers of the proximal straight portion 11 and the connector 120 is represented by an axis O1.

[0022] The proximal straight portion 11 is a straight-shaped portion provided on the proximal side of the first bending portion 12 in the tube 10. In the proximal straight portion 11, the tube 10 extends linearly along the X-axis direction. The first bending portion 12 is provided at the distal end portion 1a of the first catheter 1. The first bending portion 12 is a curved portion where the tube 10 is curved. In the illustrated example, the bending direction of the first bending portion 12 is the -Y-axis direction. In other words, the first bending portion 12 is curved in the direction of directing the distal end of the first catheter 1 in the -Y-axis direction. The bending direction of the first bending portion 12 is not limited to the -Y-axis direction and can be arbitrarily determined. The radius of curvature R1 of the first bending portion 12 shown in FIG. 3 can be arbitrarily determined. The distal straight portion 13 is a straight-shaped portion provided on the distal side of the first bending portion 12 in the tube 10. As shown in FIG. 3, the length L13 of the distal straight portion 13 can be arbitrarily determined. The length L13 is the length from the proximal end to the distal end of the distal straight portion 13. The length L13 can also be said to be the length from the proximal end of the distal straight portion 13 to the distal end of the first catheter 1, in other words, to the distal end of the distal tip 110. The tube 10 of the first catheter 1 has a constant outer diameter Φ11 throughout from the proximal end to the distal end. The tube 10 of the first catheter 1 has a constant inner diameter Φ12 throughout from the proximal end to the distal end. The inner diameter Φ12 of the tube 10 is the inner diameter of the first lumen 1L.

[0023] Returning to FIG. 1, the description will be continued. The tip chip 110 is an annular member disposed at the tip of the first catheter 1. The tip chip 110 is joined to the tip of the straight portion 13 on the tip side of the tube 10. The tip chip 110 can be formed of either a resin material having radiopacity or a metal material having radiopacity. As the resin material having radiopacity, for example, a material in which a radiopaque material such as bismuth trioxide, tungsten, or barium sulfate is mixed with at least one of polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, and fluororesin can be used. As the metal material having radiopacity, for example, gold, platinum, tungsten, or an alloy containing these elements can be used. Thus, if the tip chip 110 is formed of a material having radiopacity, the operator can visually observe the tip position of the first catheter 1 under an X-ray image. The tip chip 110 does not have to be radiopaque.

[0024] The connector 120 is disposed at the proximal end portion 1b of the first catheter 1 and is a member used when the operator operates the first catheter 1. The connector 120 has a cylindrical body 121 and vanes 122. The cylindrical body 121 is a hollow cylindrical member having an outer shape with an outer diameter that decreases from the proximal end side to the distal end side. The proximal end portion 10b of the tube 10 is fixed in a state of being inserted into the distal end side of the cylindrical body 121. An opening 123 communicating with the first lumen 1L is provided at the proximal end of the cylindrical body 121. The operator inserts the second catheter 2 or other medical devices into the first lumen 1L of the first catheter 1 through the opening 123. The vane 122 is a portion extending in the ±Y-axis direction from the outer surface of the cylindrical body 121. The vane 122 is used when the operator grips the first catheter 1. The cylindrical body 121 and the vane 122 may be integrally formed or may be formed as separate members. The connector 120 can be formed of a resin material. Examples of the resin material include polycarbonate, polyamide, polysulfone, polyurethane, polypropylene, and rigid polyvinyl chloride.

[0025] The second catheter 2 includes a tube 20, a tip chip 210, and a connector 220. The second catheter 2 is used by being inserted into the first catheter 1. The second catheter 2 is slidable longitudinally inside the first lumen 1L. In other words, the second catheter 2 can move longitudinally inside the first lumen 1L.

[0026] The tube 20 is a hollow tubular body having an elongated outer shape. The tube 20 has the same configuration as the tube 10 of the first catheter 1. Specifically, the tube 20 has a configuration in which a mesh assembly is embedded inside a main body portion formed of a resin material. The main body portion of the second catheter 2 can be formed using the same material as the main body portion 101 of the first catheter 1. The main body portion of the second catheter 2 and the main body portion 101 may be the same material or different materials. The mesh assembly of the second catheter 2 can be formed using the same material as the mesh assembly 102 of the first catheter 1. The mesh assembly of the second catheter 2 and the mesh assembly 102 may be the same material or different materials. The inner cavity of the tube 20 is also referred to as the second lumen. A therapeutic medical device is inserted into the second lumen.

[0027] The tube 20 has a first straight portion 21, a second curved portion 22, and a second straight portion, from the proximal end side toward the distal end side. In FIG. 1, the axis passing through the centers of the first straight portion 21 and the connector 220 is represented by an axis O2.

[0028] In the first straight portion 21, it is a linear portion provided on the proximal end side of the tube 20 with respect to the second curved portion 22. In the first straight portion 21, the tube 20 extends linearly along the X-axis direction. The second curved portion 22 is provided at the distal end portion 2a of the second catheter 2. The second curved portion 22 is a curved portion where the tube 20 is curved. In the illustrated example, the bending direction of the second curved portion 22 is the -Y-axis direction. In other words, the second curved portion 22 is curved in the direction of pointing the distal end of the second catheter 2 in the -Y-axis direction. The bending direction of the second curved portion 22 is not limited to the -Y-axis direction and can be arbitrarily determined. The radius of curvature R2 of the second curved portion 22 shown in FIG. 3 can be arbitrarily determined. In the illustrated example, the radius of curvature R2 of the second curved portion 22 of the second catheter 2 is larger than the radius of curvature R1 of the first curved portion 12 of the first catheter 1. The second straight portion 23 is a linear portion provided on the distal end side of the tube 20 with respect to the second curved portion 22. As shown in FIG. 3, the length L23 of the second straight portion 23 can be arbitrarily determined. The length L23 is the length from the proximal end of the second straight portion 23 to the distal end of the second straight portion 23. The length L23 can also be said to be the length from the proximal end of the second straight portion 23 to the distal end of the second catheter 2, in other words, to the distal end of the tip chip 210. The tube 20 of the second catheter 2 has a constant outer diameter Φ21 over the entire length from the proximal end to the distal end. The outer diameter Φ21 of the second catheter 2 is smaller than the outer diameter Φ11 of the first catheter 1 and smaller than the inner diameter Φ12 of the first catheter 1.

[0029] Returning to FIG. 1, the description will be continued. The tip chip 210 is an annular member disposed at the tip of the second catheter 2. The tip chip 210 is joined to the tip of the second straight portion 23 of the tube 20. The tip chip 210 can be formed of either a resin material having radiopacity or a metal material having radiopacity, similar to the tip chip 110. The tip chip 210 of the second catheter 2 and the tip chip 110 of the first catheter 1 may be made of the same material or different materials. If the tip chip 210 is formed of a radiopaque material, the operator can visually observe the tip position of the second catheter 2 under an X-ray image. The tip chip 210 does not necessarily have to be radiopaque.

[0030] The connector 220 is disposed at the proximal end portion 2b of the second catheter 2 and is a member used when the operator operates the second catheter 2. The connector 220 has a cylindrical body 221 and vanes 222. The cylindrical body 221 is a hollow cylindrical member having an outer shape with an outer diameter that decreases from the proximal end side to the distal end side. The proximal end portion 20b of the tube 20 is fixed in a state of being inserted into the distal end side of the cylindrical body 221. An opening 223 communicating with the second lumen is provided at the proximal end of the cylindrical body 221. The operator inserts a therapeutic medical device into the second lumen of the second catheter 2 through the opening 223. The vanes 222 are portions extending in the ±Y-axis directions from the outer surface of the cylindrical body 221. The vanes 222 are used when the operator grips the second catheter 2. The cylindrical body 221 and the vanes 222 may be integrally formed or may be configured as separate members. The connector 220 can be formed of an arbitrary resin material, similar to the connector 120. The connector 220 of the second catheter 2 and the connector 220 of the first catheter 1 may be made of the same material or different materials.

[0031] FIG. 4 is a diagram for explaining the shape change of the first catheter 1. In FIG. 4, the first catheter 1 in a state where the second catheter 2 is not inserted is represented by a solid line. In FIG. 4, the second catheter 2 having the first rigidity and the first catheter 1 in a state where the second catheter 2 is inserted are represented by a broken line. In FIG. 4, the second catheter 2' having the second rigidity and the first catheter 1 in a state where the second catheter 2' is inserted are represented by a one-dot chain line. The second rigidity is greater than the first rigidity. When using the catheter system 1000, the operator inserts the second catheter 2 into the first catheter 1 and performs a coronary artery selection operation with the distal end of the second catheter 2 protruding from the distal end of the first catheter 1. As shown by the broken line, when the second catheter 2 is inserted into the first catheter 1, the second catheter 2 serves as a core material and the bending shape of the first bending portion 12 of the first catheter 1 becomes loose. As shown by the one-dot chain line, when the second catheter 2' is inserted into the first catheter 1, the second catheter 2' serves as a core material and the bending shape of the first bending portion 12 of the first catheter 1 becomes loose. The second rigidity of the second catheter 2' is greater than the first rigidity of the second catheter 2. Therefore, when the second catheter 2' is inserted, the bending shape of the first bending portion 12 becomes even looser than when the second catheter 2 is inserted. Thus, the shape of the first catheter 1 during use is affected by the ratio of the rigidity of the first catheter 1 and the rigidity of the second catheter 2.

[0032] Hereinafter, the ratio of the rigidity of the first catheter 1 to the rigidity of the second catheter 2 will be examined. The operator prepared five samples SA1 to SA5 of the first catheter 1 with different rigidities. The operator prepared six samples SB1 to SB6 of the second catheter 2 with different rigidities. The operator prepared the samples SA1 to SA5 of the first catheter 1 with a length of 80 mm including the first curved portion 12. The operator prepared the samples SB1 to SB6 of the second catheter 2 with a length of 80 mm on the proximal side of the second curved portion 22. The proximal side of the second curved portion 22 is a portion of the second catheter 2 that does not include the second curved portion 22 and is on the proximal side of the second curved portion 22. In the example of FIG. 2, the proximal side of the second curved portion 22 is the first straight portion 21. The operator performed a three-point bending test on each of the samples SA1 to SA5 and the samples SB1 to SB6 to measure the rigidity.

[0033] FIG. 5 is a diagram for explaining the method of the three-point bending test. In the three-point bending test, the operator prepared a testing machine 60 and a loading device 70. The testing machine 60 has a first support portion 61 and a second support portion 62. The first support portion 61 and the second support portion 62 are arranged apart from each other and are columnar members having a U-shaped groove on the upper part. The loading device 70 includes a pressing portion 71 and a sensor capable of measuring the weight added by the pressing portion 71. The operator performed the following a1 to a4 on each of the samples SA1 to SA5 and the samples SB1 to SB6. Hereinafter, one sample to be measured is referred to as "sample S". (a1) The operator set the distance l between the fulcrums between the first support portion 61 and the second support portion 62 to 50 mm and prepared the sample S in a dry state. The distance l between the fulcrums is the linear distance between the center of the first support portion 61 and the center of the second support portion 62. (a2) The operator supported one end portion of the sample S by the first support portion 61 and supported the other end portion of the sample S by the second support portion 62. (a3) The operator applied a pressing load to the sample S by moving the pressing part 71 of the loading device 70 in the direction of the white arrow. The operator set the linear distance c from the fulcrums of the first support part 61 and the second support part 62 to the end point of the movement of the pressing part 71 to 5 mm. The linear distance c is also called the pressing distance. The operator set the moving speed of the pressing part 71 to 36 mm / min. (a4) During procedure a3, the operator used the detection value detected by the loading device 70 as the rigidity index value representing the rigidity of the sample S. In this embodiment, the rigidity index values of each sample were shown as ratios when the rigidity index value of the sample SA2 was 1.

[0034] The ratios of the samples SA1 to SA5 for the first catheter 1 were as follows. The ratio of the sample SA1 was 0.5. The ratio of the sample SA2 was 1.0. The ratio of the sample SA3 was 1.4. The ratio of the sample SA4 was 1.9. The ratio of the sample SA5 was 2.8. The ratios of the samples SB1 to SB6 for the second catheter 2 were as follows. The ratio of the sample SB1 was 0.7. The ratio of the sample SB2 was 0.6. The ratio of the sample SB3 was 1.3. The ratio of the sample SB4 was 1.0. The ratio of the sample SB5 was 0.6. The ratio of the sample SB6 was 0.3.

[0035] Consider the first catheter 1. Since the sample SA1 of the first catheter 1 has a relatively too low rigidity index value, its rigidity is insufficient. Therefore, when the second catheter 2 is inserted into the sample SA1, the bending shape of the first bending portion 12 becomes loose, which is not preferable. The fact that the bending shape of the first bending portion 12 becomes loose means that the bending shape of the first bending portion 12 almost disappears and the function of the first catheter 1 is impaired. The samples SA4 and SA5 of the first catheter 1 are not preferable from the viewpoint of safety for the living body in the artificial valve implantation environment because their rigidity index values are relatively too high. The samples SA2 and SA3 of the first catheter 1 are preferable because they achieve both the rigidity to withstand the insertion of the second catheter 2 and the safety for the living body. Hereinafter, the rigidity ratios of the samples SB1 to SB6 of the second catheter 2 based on the sample SA2 of the first catheter 1 will be considered.

[0036] Figure 6 is a graph showing the rigidity ratios. The horizontal axis of Figure 6 represents each sample. The vertical axis of Figure 6 represents the ratio. The operator obtained the ratio of the rigidity of the sample SA2 to the rigidity of other samples by calculating "(rigidity index value of other samples) / (rigidity index value of sample SA2)". Figure 6 shows the obtained ratios as bar graphs. In Figure 6, the ratio of the reference sample SA2 is 1.0.

[0037] Since the ratio of the rigidity index value of sample SB3 to that of sample SA2, i.e., (rigidity index value of sample SB3) / (rigidity index value of sample SA2), exceeds 1, the rigidity of the second catheter 2 relative to the rigidity of the first catheter 1 is too high. Therefore, when the sample SB3 of the second catheter 2 is inserted into the first catheter 1, the bending shape of the first bending portion 12 of the first catheter 1 becomes loose, so that the bending shape of the first bending portion 12 almost disappears, and the function of the first catheter 1 is impaired. Since the ratio of the rigidity index value of sample SB6 to that of sample SA2, i.e., (rigidity index value of sample SB6) / (rigidity index value of sample SA2), is only 0.3, the rigidity of the second catheter 2 relative to the rigidity of the first catheter 1 is too low. Therefore, when the sample SB6 of the second catheter 2 is inserted into the first catheter 1, although the shape of the first bending portion 12 of the first catheter 1 can be maintained, insufficient torque transmission of the second catheter 2 occurs, and when the second catheter 2 is arranged near the artificial valve, the tip of the catheter is deformed and does not conform to the shape of the aorta. In sample SB6, it becomes difficult to direct the tip in the intended direction when the catheter is rotated, and it is difficult to select a blood vessel using the second catheter 2. Thus, it can be seen that samples SB1, SB2, SB4, and SB5 surrounded by the dashed line in Fig. 6 are preferable as the second catheter 2. That is, it can be seen that the rigidity of the second catheter 2 preferably satisfies the following formula (1). 0.6 ≤ (rigidity of the second catheter 2) / (rigidity of the first catheter 1) ≤ 1 ···(1)

[0038] As described with reference to Figs. 5 and 6, formula (1) can be rephrased as the following formula (2). 0.6 ≤ (rigidity of the proximal side of the second bending portion 22 of the second catheter 2) / (rigidity of the first bending portion 12 of the first catheter 1) ≤ 1 ···(2)

[0039] FIG. 7 is a diagram for explaining a method of using the catheter system 1000. FIG. 8 is a diagram for explaining the center of rotation of the distal end portion 2a of the second catheter 2. FIG. 7 illustrates the aorta 90 in which the prosthetic valve 80 is placed. As a minimally invasive treatment method for aortic valve stenosis, transcatheter aortic valve implantation is known. Transcatheter aortic valve implantation is also called TAVI. As shown in FIG. 7, in TAVI, the dysfunctional aortic valve 98 is replaced with the prosthetic valve 80. The prosthetic valve 80 has a mesh-like strut 81 and a membrane 82 stretched across the strut 81. After the TAVI surgery, in the patient as shown in FIG. 7, the prosthetic valve 80 is placed in the aorta 90, and the inlet 92a of the right coronary artery 92 and the inlet 93a of the left coronary artery 93 are covered by the prosthetic valve 80. Therefore, when performing PCI on a patient after the placement of the TAVI prosthetic valve 80, the prosthetic valve 80 becomes an obstacle, making it difficult to place a catheter at the inlets 92a and 93a of the target coronary arteries 92 and 93. The catheter system 1000 of the present embodiment can facilitate PCI in such an environment where the prosthetic valve 80 is placed. Hereinafter, an entry into the left coronary artery 93 for a patient in a state where the self-expanding bioprosthetic valve 80 is placed will be exemplified and described. The catheter system 1000 is similarly applicable to an entry into the right coronary artery 92 for a patient in whom the self-expanding bioprosthetic valve 80 is placed, an entry into the left coronary artery 93 for a patient in whom a balloon-expandable bioprosthetic valve is placed, and an entry into the right coronary artery 92 for a patient in whom a balloon-expandable bioprosthetic valve is placed. The operator can perform the PCI procedure, for example, according to the following steps b1 to b7.

[0040] (b1) The operator inserts the second catheter 2 into the first catheter 1 so that the second catheter 2 is disposed in the first lumen 1L of the first catheter 1. At this time, the distal end portion 2a of the second catheter 2 does not protrude from the distal end of the first catheter 1 and is accommodated in the first lumen 1L. (b2) The operator advances the second catheter 2, which is housed in the first catheter 1, along the workhorse wire from the aorta 90 into the ascending aorta 91. As shown in FIG. 7, the operator positions the distal end 1a of the first catheter 1 proximal to the artificial valve 80 and near the center of the artificial valve 80.

[0041] (b3) The operator protrudes the distal end 2a of the second catheter 2 from the distal end of the first catheter 1. The operator advances the distal end 2a of the second catheter 2 toward the left coronary artery 93. The operator passes the distal end 2a of the second catheter 2 outside the artificial valve 80 through the gap 80a of the strut 81 where the membrane 82 does not exist. At this time, while maintaining the position of the first catheter 1, the operator adjusts the position and orientation of the distal end 2a of the second catheter 2 by rotating only the second catheter 2. As shown in FIG. 8, when the operator rotates the proximal end 2b of the second catheter 2 in the circumferential direction with the distal end 2a of the second catheter 2 protruding from the distal end 1d of the first catheter 1, the rotation center C of the distal end 2a of the second catheter 2 is located on the straight line SL. The straight line SL is a straight line connecting the distal end 1d of the first catheter 1 and the second curved portion 22 of the second catheter 2. In other words, when the operator rotates the proximal end 2b of the second catheter 2 in the circumferential direction with the distal end 2a of the second catheter 2 protruding from the distal end 1d of the first catheter 1, only the distal end 2a of the second catheter 2 protruding from the distal end 1d rotates while the first catheter 1 maintains its position without rotating significantly. (b4) The operator inserts the distal end 2a of the second catheter 2 from the inlet 93a of the left coronary artery 93 outside the artificial valve 80 into the left coronary artery 93. At this time, similar to the procedure b3, while maintaining the position of the first catheter 1, the operator inserts the distal end 2a of the second catheter 2 into the left coronary artery 93 by rotating only the second catheter 2 to adjust the position and orientation of the distal end 2a of the second catheter 2.

[0042] (b5) While maintaining the position of the second catheter 2, the operator advances the first catheter 1 distally. The distal end 1a of the first catheter 1 advances distally along the second catheter 2 that has already been passed through the gap 80a of the artificial valve 80, passes through the gap 80a of the artificial valve 80, and reaches the inlet 93a of the left coronary artery 93. (b6) The operator performs a procedure using a therapeutic medical device using the path to the left coronary artery 93 secured by the first catheter 1. At this time, the operator may remove the second catheter 2 leaving only the first catheter 1 to secure the inner diameter. The operator may leave the second catheter 2 inserted into the first catheter 1 without removing it to maintain rigidity. The operator may insert a microcatheter into the second lumen of the second catheter 2 to obtain additional support force. (b7) After the treatment, the operator removes the first catheter 1 from the left coronary artery 93. When removing, the first catheter 1 may get caught on the strut 81 of the artificial valve 80 or the like. In such a case, the operator reinserts the second catheter 2 into the first catheter 1, protrudes the distal end 2a of the second catheter 2 from the distal end of the first catheter 1, and rotates the distal end 2a. By doing so, the operator can release the catch of the first catheter 1 and smoothly remove the first catheter 1.

[0043] The second catheter 2 described in FIGS. 1 and 3 is suitable when an approach using a small distal end 2a is required. Examples of the case where an approach using a small distal end 2a is required include, for example, the case where the artificial valve 80 is placed relatively higher with respect to the patient's aortic valve 98 and the coronary arteries 92, 93 are located below the artificial valve 80. Examples of the case where an approach using a small distal end 2a is required include, for example, the case where there is a space outside the aortic sinus 94.

[0044] As described above, according to the catheter system 1000 of the first embodiment, by inserting the second catheter 2 having the second bending portion 22 inside the first catheter 1 having the first bending portion 12, two bending portions are realized by two catheters. Therefore, compared with the case where two bending portions are realized by one catheter, it is possible to suppress the springing of the distal ends 1a and 2a of the first catheter 1 and the second catheter 2 accompanying the rotation operation, and fine operations such as rotating only the distal end 2a of the second catheter 2 become possible. Since the second catheter 2 is disposed inside the first catheter 1, the outer diameter Φ21 of the second catheter 2 is smaller than the outer diameter Φ11 of the first catheter 1. Therefore, after delivering the distal end 1a of the first catheter 1 near the artificial valve 80, the operator can project the distal end 2a of the second catheter 2 from the distal end of the first catheter 1, and by using the distal end 2a of the relatively thin-diameter second catheter 2, the distal end 2a can be smoothly passed through the gap 80a between the struts 81 of the artificial valve 80.

[0045] According to the catheter system 1000 of the first embodiment, since the rigidity of the second catheter 2 satisfies the formula (1), the flexibility and torque transmission of the first catheter 1 in the state where the second catheter 2 is inserted can be maintained. Therefore, the operator can smoothly deliver the first catheter 1 with the second catheter 2 inserted to the vicinity of the artificial valve 80. Since the rigidity of the second catheter 2 satisfies the formula (1), the second catheter 2 can be made less likely to buckle. Therefore, when the second catheter 2 is pushed forward in the first catheter 1, it is possible to suppress buckling of the second catheter 2. Since the rigidity of the second catheter 2 satisfies the formula (1), the torque transmission of the second catheter 2 can be improved. Therefore, after the operator projects the distal end 2a of the second catheter 2 from the distal end of the first catheter 1, by applying a rotation operation to the second catheter 2, an operation of passing the distal end 2a of the second catheter 2 through the gap 80a between the struts 81 of the artificial valve 80 and selection of the target coronary arteries 92 and 93 in PCI can be facilitated. As a result, according to the catheter system 1000, the operator can facilitate the percutaneous procedure in the artificial valve placement environment.

[0046] According to the catheter system 1000 of the first embodiment, as shown in FIG. 8, the rotation center C of the distal end portion 2a of the second catheter 2 is located on the straight line SL connecting the distal end 1d of the first catheter 1 and the second bending portion 22. That is, the operator can rotate only the distal end portion 2a of the second catheter 2 on the distal end side of the distal end 1d of the first catheter 1 while maintaining the position of the first catheter 1. Therefore, it is possible to suppress the movement of the first catheter 1 due to the rotation operation of the second catheter 2 and to prevent the first catheter 1 from interfering with the artificial valve 80. Since a fine operation such as rotating only the distal end portion 2a of the second catheter 2 is possible, it is possible to easily pass through the gap 80a of the strut 81 of the artificial valve 80, and in the case of PCI, it is possible to easily select the target coronary arteries 92, 93 by the distal end portion 2a of the second catheter 2.

[0047] <Second Embodiment> FIG. 9 is an enlarged view of the distal end side of the second catheter 2A of the second embodiment. FIG. 10 is an enlarged view of the second catheter 2A viewed from the A direction in FIG. 9. The catheter system 1000A of the second embodiment includes a second catheter 2A instead of the second catheter 2 in the configuration described in the first embodiment. The second catheter 2A includes a tube 20A instead of the tube 20 in the configuration described in the first embodiment.

[0048] The tube 20A has, from the proximal end side toward the distal end side, a first straight portion 21, a second curved portion 22, a second straight portion 23, a third curved portion 24, and a third straight portion 25. The first straight portion 21, the second curved portion 22, and the second straight portion 23 are as described in the first embodiment. The second straight portion 23 is provided on the tube 20A on the distal end side of the second curved portion 22 and on the proximal end side of the third curved portion 24. The third curved portion 24 is the distal end portion 2a of the second catheter 2A and is provided on the distal end side of the second curved portion 22. The third curved portion 24 is a curved portion where the tube 20A is curved. The third straight portion 25 is a linear portion provided on the tube 20A on the distal end side of the third curved portion 24. The length L25 of the third straight portion 25 can be arbitrarily determined. The tube 20A of the second catheter 2A has a constant outer diameter Φ21A over the entire length from the proximal end to the distal end. The outer diameter Φ21A is smaller than the outer diameter Φ11 of the first catheter 1 described in FIG. 3 and smaller than the inner diameter Φ12 of the first catheter 1 described in FIG. 2.

[0049] FIG. 11 is a perspective view of the second catheter 2A. FIG. 12 is an enlarged view of the second catheter 2A as viewed from the B direction in FIG. 11. FIGS. 11 and 12 illustrate a virtual plane VP parallel to both the first straight portion 21 and the second straight portion 23. As shown in FIGS. 11 and 12, the operator aligns the second catheter 2A such that the direction from the proximal end side to the distal end side of the second straight portion 23 is in the direction from the lower side to the upper side in the vertical direction. The vertical direction is the Y-axis direction shown in FIGS. 11 and 12. When the second catheter 2A in this state is viewed from the B direction in FIG. 11, the portion of the second catheter 2A on the distal end side of the third curved portion 24 is located on the virtual plane VP (FIG. 12). The B direction in FIG. 11 is the direction from the proximal end side to the distal end side of the first straight portion 21.

[0050] Thus, the configuration of the second catheter 2A can be variously modified, and the second catheter 2A may have a third bending portion 24 provided on the distal end side of the second bending portion 22. The catheter system 1000A of the second embodiment can achieve the same effects as those of the first embodiment.

[0051] FIG. 13 is a diagram for explaining an approach to the left coronary artery 93 using the second catheter 2A. In FIG. 13, the state of the aorta 90 and the artificial valve 80 as viewed from the patient's head side is illustrated, and the illustration of the membrane of the artificial valve 80 is omitted. According to the catheter system 1000A of the second embodiment, the second catheter 2A has a third bending portion 24 provided on the distal end side of the second bending portion 22. For this reason, the second catheter 2A can cause a more complex movement by the distal end portion 2a of the second catheter 2A as compared with the configuration having only the second bending portion 22. As a result, as shown in FIG. 13, the second catheter 2A can easily access the inlet 93a existing in a difficult-to-access location by using the third bending portion 24. As shown in FIG. 12, since the portion of the second catheter 2A on the distal end side of the third bending portion 24 is located on the virtual plane VP, the second catheter 2A can be configured to be suitable for an approach to the left coronary artery 93 in PCI (FIG. 13).

[0052] <Third Embodiment> FIG. 14 is an enlarged view of the distal end side of the second catheter 2B of the third embodiment. FIG. 15 is an enlarged view of the second catheter 2B as viewed from the A direction in FIG. 14. The catheter system 1000B of the third embodiment includes a second catheter 2B instead of the second catheter 2 in the configuration described in the first embodiment. The second catheter 2B includes a tube 20B instead of the tube 20 in the configuration described in the first embodiment.

[0053] The tube 20B has, from the proximal end side toward the distal end side, a first straight portion 21, a second curved portion 22, a second straight portion 23, a third curved portion 24B, and a third straight portion 25B. The first straight portion 21, the second curved portion 22, and the second straight portion 23 are as described in the first embodiment. The second straight portion 23 is provided on the tube 20B on the distal end side of the second curved portion 22 and on the proximal end side of the third curved portion 24B. The third curved portion 24B is the distal end portion 2a of the second catheter 2B and is provided on the distal end side of the second curved portion 22. The third curved portion 24B is a curved portion where the tube 20B is curved. The third straight portion 25B is a linear portion provided on the tube 20B on the distal end side of the third curved portion 24B. The length L25B of the third straight portion 25B can be arbitrarily determined. The tube 20B of the second catheter 2B has a constant outer diameter Φ21B over the entire length from the proximal end to the distal end. The outer diameter Φ21B is smaller than the outer diameter Φ11 of the first catheter 1 described in FIG. 3 and smaller than the inner diameter Φ12 of the first catheter 1 described in FIG. 2.

[0054] FIG. 16 is a perspective view of the second catheter 2B. FIG. 17 is an enlarged view of the second catheter 2B as viewed from the B direction in FIG. 16. FIGS. 16 and 17 illustrate a virtual plane VP parallel to both the first straight portion 21 and the second straight portion 23. As shown in FIGS. 16 and 17, for the second catheter 2B, the direction from the proximal end side to the distal end side of the second straight portion 23 is aligned with the direction from the lower side to the upper side in the vertical direction. The vertical direction is the Y-axis direction shown in FIGS. 16 and 17. When the second catheter 2B in this state is viewed from the B direction in FIG. 16, the portion of the second catheter 2B on the distal end side of the third curved portion 24B is located on the left side of the virtual plane VP (FIG. 17). The left side of the virtual plane VP is the +Z-axis direction in FIG. 17. The B direction in FIG. 16 is the direction from the proximal end side to the distal end side of the first straight portion 21.

[0055] Thus, the configuration of the second catheter 2B can be variously modified, and the second catheter 2B may have a third bending portion 24B provided on the distal end side of the second bending portion 22. According to the catheter system 1000B of the third embodiment, the same effects as those of the first embodiment can be achieved. In the catheter system 1000B of the third embodiment, as shown in FIG. 17, in the second catheter 2B, the portion on the distal end side of the third bending portion 24B is located on the left side of the virtual plane VP. Therefore, the second catheter 2B can be configured to be suitable for approaching the left coronary artery 93 in PCI.

[0056] <Fourth Embodiment> FIG. 18 is an enlarged view of the distal end side of the second catheter 2C of the fourth embodiment. FIG. 19 is an enlarged view of the second catheter 2C as viewed from the A direction in FIG. 18. The catheter system 1000C of the fourth embodiment includes a second catheter 2C instead of the second catheter 2 in the configuration described in the first embodiment. The second catheter 2C includes a tube 20C instead of the tube 20 in the configuration described in the first embodiment.

[0057] The tube 20C has, from the proximal end side toward the distal end side, a first straight portion 21, a second curved portion 22, a second straight portion 23, a third curved portion 24C, and a third straight portion 25C. The first straight portion 21, the second curved portion 22, and the second straight portion 23 are as described in the first embodiment. The second straight portion 23 is provided on the tube 20C on the distal end side of the second curved portion 22 and on the proximal end side of the third curved portion 24C. The third curved portion 24C is the distal end portion 2a of the second catheter 2C and is provided on the distal end side of the second curved portion 22. The third curved portion 24C is a curved portion where the tube 20C is curved. The third straight portion 25C is a linear portion provided on the tube 20C on the distal end side of the third curved portion 24C. The length L25C of the third straight portion 25C can be arbitrarily determined. The tube 20C of the second catheter 2B has a constant outer diameter Φ21C over the entire length from the proximal end to the distal end. The outer diameter Φ21C is smaller than the outer diameter Φ11 of the first catheter 1 described in FIG. 3 and smaller than the inner diameter Φ12 of the first catheter 1 described in FIG. 2.

[0058] FIG. 20 is a perspective view of the second catheter 2C. FIG. 21 is an enlarged view of the second catheter 2C viewed from the B direction of FIG. 20. FIGS. 20 and 21 illustrate a virtual plane VP parallel to both the first straight portion 21 and the second straight portion 23. As shown in FIGS. 20 and 21, for the second catheter 2C, the direction from the proximal end side to the distal end side of the second straight portion 23 is aligned with the direction from the lower side to the upper side in the vertical direction. The vertical direction is the Y-axis direction shown in FIGS. 20 and 21. When the second catheter 2C in this state is viewed from the B direction of FIG. 20, the portion of the second catheter 2C on the distal end side of the third curved portion 24C is located on the right side of the virtual plane VP (FIG. 21). The right side of the virtual plane VP is the -Z-axis direction in FIG. 21. The B direction of FIG. 20 is the direction from the proximal end side to the distal end side of the first straight portion 21.

[0059] Thus, the configuration of the second catheter 2C can be variously modified, and the second catheter 2C may have a third bending portion 24C provided on the distal end side of the second bending portion 22. The catheter system 1000C of the fourth embodiment can achieve the same effects as those of the first embodiment. In the catheter system 1000C of the fourth embodiment, as shown in FIG. 21, in the second catheter 2C, the portion on the distal end side of the third bending portion 24C is located on the right side of the virtual plane VP. For this reason, the second catheter 2C can be configured to be suitable for an approach to the right coronary artery 92 in PCI. In particular, the second catheter 2C is suitable for a case where the derivation of the right coronary artery 92 from the ascending aorta 91 is special. Examples of a case where the derivation of the right coronary artery 92 from the ascending aorta 91 is special include a case where the right coronary artery 92 is connected to the ascending aorta 91 while being inclined vertically or horizontally. The right coronary artery 92 being connected while being inclined vertically means that the right coronary artery 92 extending from the ascending aorta 91 is directed upward or downward. The right coronary artery 92 being connected while being inclined horizontally means that the right coronary artery 92 extends so as to wrap around the outer periphery of the ascending aorta 91.

[0060] <Modification Example of the Present Embodiment> The present disclosure is not limited to the above-described embodiments, and can be implemented in various aspects without departing from the gist thereof. For example, the following modifications are also possible.

[0061] [Modification Example 1] In the above-described first to fourth embodiments, an example of the configuration of the catheter systems 1000, 1000A to 1000C was shown. The configuration of the catheter systems 1000, 1000A to 1000C can be variously modified. For example, the operator can appropriately select the second catheter 2 described in the first embodiment, the second catheter 2A described in the second embodiment, the second catheter 2B described in the third embodiment, and the second catheter 2C described in the fourth embodiment according to the patient's condition and the location of the lesion. Examples of the patient's condition include the shape of the patient's coronary artery arch, the size of the implanted artificial valve 80, the position and inclination of the implanted artificial valve 80, and the site for inserting the catheter such as the left femoral artery, the right femoral artery, the left radial artery, the right radial artery, the left brachial artery, and the right brachial artery. Examples of the location of the lesion can be whether the lesion is in the right coronary artery 92 or the left coronary artery 93.

[0062] For example, in the first catheter 1, the operator may prepare in advance a plurality of first catheters 1 having different curvature radii R1 of the first curved portion 12 and lengths L13 of the distal straight portion 13. In the second catheters 2, 2A to 2C, the operator may prepare in advance a plurality of second catheters 2, 2A to 2C in which at least a part of the curvature radius R2 of the second curved portion 22, the length L23 of the second straight portion 23, the curvature radii of the third curved portions 24, 24B, 24C, and the lengths L25, L25B, L25C of the third straight portions 25, 25B, 25C are different. The operator can appropriately select a device suitable for the procedure from these plurality of first catheters 1 and second catheters 2, 2A to 2C according to the patient's condition and the location of the lesion.

[0063] [Modification Example 2] In the above-described first to fourth embodiments, an example of the configuration of the first catheter 1 and the second catheters 2, 2A to 2C was shown. The configuration of the first catheter 1 and the second catheters 2, 2A to 2C can be variously modified. For example, at least one of the first catheter 1 and the second catheters 2, 2A to 2C may not include a part of the above-described configuration. For example, at least one of the first catheter 1 and the second catheters 2, 2A to 2C may further include a configuration not described above.

[0064] For example, at least one of the first catheter 1 and the second catheters 2, 2A to 2C may be provided with a coating layer formed of a hydrophilic resin or a hydrophobic resin. For example, the first catheter 1 may not have a tip 110. For example, at least one of the second catheters 2, 2A to 2C may not have a tip 210. For example, at least one of the first catheter 1 and the second catheters 2, 2A to 2C may be configured as a multi-lumen catheter.

[0065] For example, at least one of the tube 10 and the tubes 20, 20A to 20C may not have a braided structure. For example, at least one of the tube 10 and the tubes 20, 20A to 20C may be configured by joining two or more tubes having different rigidities and materials. The two or more tubes may be arranged side by side along the longitudinal direction. The two or more tubes may be arranged in layers in the circumferential direction. For example, at least one of the tube 10 and the tubes 20, 20A to 20C may be made of metal.

[0066] [Modification Example 3] The second catheters 2, 2A to 2C of the first to fourth embodiments and the second catheters 2, 2A to 2C of the first and second modification examples may be combined as appropriate.

[0067] The present aspect has been described based on the embodiments and modification examples. The embodiments of the above-described aspect are for facilitating the understanding of the present aspect and do not limit the present aspect. The present aspect can be changed and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in the present aspect. If its technical features are not described as essential in this specification, they can be deleted as appropriate.

Claims

1. A catheter system (1000, 1000A to 1000C), comprising: a first catheter (1) having a curved first bending portion (12) provided at a distal end portion and a first lumen provided inside; a second catheter (2, 2A to 2C) having a curved second bending portion (22) provided at a distal end portion and a rigidity satisfying the following formula (1), and being slidably disposed longitudinally inside the first lumen; The catheter system (1000, 1000A to 1000C) comprising the above. 0.6 ≤ (rigidity of the second catheter (2, 2A to 2C)) / (rigidity of the first catheter (1)) ≤ 1... (1)

2. The catheter system (1000, 1000A to 1000C) according to Claim 1, wherein the second catheter (2, 2A to 2C) has a rigidity satisfying the following formula (2). 0.6 ≤ (rigidity of the proximal side of the second catheter (2, 2A to 2C) from the second bending portion (22)) / (rigidity of the first bending portion (12) of the first catheter (1)) ≤ 1... (2)

3. The catheter system (1000A to 1000C) according to Claim 1 or Claim 2, wherein the second catheter (2A to 2C) further has a curved third bending portion (24, 24B, 24C) provided on the distal side of the second bending portion (22).

4. The catheter system (1000A to 1000C) according to Claim 3, wherein the second catheter (2A to 2C) further has a straight first straight portion (21) provided on the proximal side of the second bending portion (22); and a straight second straight portion (23) provided on the distal side of the second bending portion (22) and on the proximal side of the third bending portion (24, 24B, 24C).

5. The catheter system (1000A) according to Claim 4, wherein In the catheter system (1000A), when the second catheter (2A) with the direction from the proximal end side to the distal end side of the second straight portion (23) aligned with the direction from the lower side to the upper side in the vertical direction is viewed from the direction from the proximal end side to the distal end side of the first straight portion (21), the portion on the distal end side of the third bending portion (24) is located on a virtual plane parallel to both the first straight portion (21) and the second straight portion (23).

6. The catheter system (1000B) according to claim 4, In the catheter system (1000B), when the second catheter (2B) with the direction from the proximal end side to the distal end side of the second straight portion (23) aligned with the direction from the lower side to the upper side in the vertical direction is viewed from the direction from the proximal end side to the distal end side of the first straight portion (21), the portion on the distal end side of the third bending portion (24B) is located on the left side of a virtual plane parallel to both the first straight portion (21) and the second straight portion (23).

7. The catheter system (1000C) according to claim 4, In the catheter system (1000C), when the second catheter (2C) with the direction from the proximal end side to the distal end side of the second straight portion (23) aligned with the direction from the lower side to the upper side in the vertical direction is viewed from the direction from the proximal end side to the distal end side of the first straight portion (21), the portion on the distal end side of the third bending portion (24C) is located on the right side of a virtual plane parallel to both the first straight portion (21) and the second straight portion (23).

8. The catheter system (1000, 1000A to 1000C) according to any one of claims 1 to 7, when the proximal end portion of the second catheter (2, 2A to 2C) is rotationally operated in the circumferential direction with the distal end portion of the second catheter (2, 2A to 2C) protruding from the distal end of the first catheter (1), the rotation center of the distal end portion of the second catheter (2, 2A to 2C) is located on a straight line connecting the distal end of the first catheter (1) and the second bending portion (22).

Images