catheter

Abstract

The purpose of the present invention is to provide an asymmetrical bending-type catheter in which the bent shape of a distal section of the catheter differs between one side and the other side.　This catheter includes: a shaft; a first wire and a second wire; a plate spring arranged so as to divide an internal cavity in the shaft into a first section in which the first wire is arranged and a second section in which the second wire is arranged; a support member; and a first coil having an internal cavity in which the first wire is arranged. The first coil is fixed to at least two locations on the proximal end side of the plate spring, the first coil has a total length L1 when in a natural state and a total length LC1 when maximally compressed, and the ratio LC1 / L1 thereof is 0.9 or more.

Description

[Technical field]

[0001] The present invention relates to a catheter having a bendable tip. [Background technology]

[0002] Electrode catheters having multiple electrodes at their distal portions are used to measure potentials in the heart and perform pacing. Some of these electrode-equipped catheters have a distal portion that can be bent by operating a handle so that the distal portion of the catheter can be easily positioned at a desired site in the heart. In general, the distal portion of such catheters can be bent by pulling a pull wire fixed inside the tip of the catheter. Furthermore, a catheter equipped with two pull wires has been proposed to bend the catheter to both sides on one side and the other side around the longitudinal direction of the catheter.

[0003] For example, Patent Document 1 discloses a tip-deflectable catheter that includes multiple operation tubes with operation wires disposed in the inner cavity of the catheter tube, and that is divided into multiple partial tubes, allowing the tip of the catheter to be deformed into a smoothly curved shape without bending along the way. Also proposed are tip-deflectable catheters that can prevent the tip electrode, leaf spring, and pull wire disposed inside the tip of the catheter from falling off even when the tip of the catheter is curved (Patent Documents 2 and 3), and catheters with different curved shapes on one side and the other side (Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-200445 A [Patent Document 2] JP 2010-75530 A [Patent Document 3] JP 2015-100515 A [Patent Document 4] JP 2012-147971 A [Patent Document 5] Special Publication No. 2017-518122 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to deliver the distal part of the catheter to the optimal site according to the size and purpose of the heart, it is necessary to make the catheter asymmetrically curved, not only so that the distal part of the catheter can be curved to either one side or the other side, but also so that the curved diameters are different. In addition, by increasing the degree of asymmetric curvature, it becomes possible to easily deliver the distal part of the catheter to the desired site. However, with the configurations such as those in Patent Documents 4 and 5, it is difficult to make a catheter with a higher degree of asymmetric curvature diameter.

[0006] The present invention has been made in consideration of the above circumstances, and its object is to provide an asymmetrically curved type catheter in which the distal portion of the catheter can be curved to either one side or the other side, and the curved shapes are different for each side. [Means for solving the problem]

[0007] The catheter that has been able to solve the above problem includes: a shaft having a distal end and a proximal end and having an inner lumen extending in a longitudinal direction; a first wire and a second wire having a distal end and a proximal end, the distal end being fixed to the distal end of the shaft and the proximal end being disposed at the proximal end of the shaft, extending into the inner lumen of the shaft; a leaf spring that is disposed in the inner lumen of the shaft so as to separate the inner lumen of the shaft in the longitudinal direction into a first portion in which the first wire is disposed and a second portion in which the second wire is disposed; and a leaf spring that extends in the longitudinal direction and has an inner lumen in which the first wire and the second wire are disposed, the proximal end of the leaf spring being fixed, and the leaf spring being disposed in the inner lumen of the shaft. a support member disposed proximal to the distal end of the support member, the support member having an inner cavity in which a first wire is disposed, and a first coil disposed within the first portion distal to the distal end of the support member, the first coil being fixed at at least two points on the proximal end side of the leaf spring, the first coil having a first fixed portion at which the first coil and the leaf spring are fixed, a second fixed portion located proximal to the first fixed portion at which the first coil and the leaf spring are fixed, and an intermediate non-fixed portion located between the first fixed portion and the second fixed portion and not fixed to the leaf spring, the first coil having a total length L1 in a natural state and a total length L2 at a maximum compression C1 and L C1 / L1 is 0.9 or more.

[0008] The support member is preferably a proxy tube.

[0009] The first coil is preferably uncompressed.

[0010] The portion where the first coil and the leaf spring are fixed is preferably located on a surface of the first coil facing one surface of the leaf spring.

[0011] Of the non-fixed parts of the first coil, the non-fixed part having the longest longitudinal length preferably has a length in the longitudinal direction in its natural state that is 50% or more of the total length L1 of the first coil in its natural state.

[0012] It is preferable that the first coil further has a distal side non-fixed portion between the distal end of the first coil and the first fixed portion, which does not have a fixed portion that fixes the first coil and the leaf spring.

[0013] The device further includes a second coil, the second coil having an inner lumen in which the first wire is disposed, and is preferably disposed within the first portion and distal to the first coil.

[0014] In this case, the second coil has a total length L2 in the natural state and a total length L C2 and L C2 It is preferable that / L2 is smaller than 0.9.

[0015] It is preferable that the bending rigidity of the first coil is greater than the bending rigidity of the second coil, and the difference between the bending rigidity of the first coil and the bending rigidity of the second coil is 50% or less.

[0016] The first coil comprises a first helically wound coil wire and the second coil comprises a second helically wound coil wire, the pitch spacing of the first coil being preferably smaller than the pitch spacing of the second coil.

[0017] The coil wire diameter and coil diameter of the first coil are preferably the same as the coil wire diameter and coil diameter of the second coil.

[0018] It is further preferred that the device further comprises a third coil, the third coil having an inner lumen in which the second wire is disposed, and disposed in the second portion.

[0019] The third coil has a total length L3 in its natural state and a total length L4 at maximum compression. C3 and L C3 It is preferable that / L3 is smaller than 0.9.

[0020] It is preferable that the shaft further comprises a second coil having an inner lumen in which the first wire is disposed and disposed distal to the first coil in the first section; a third coil having an inner lumen in which the second wire is disposed and disposed in the second section; and a protective tube having an inner lumen and disposed within the shaft lumen, the protective tube having the leaf spring, the first coil, the second coil, and the third coil disposed within its inner lumen.

[0021] It is preferable that the first coil has the first fixed portion and the second fixed portion fixed by welding, soldering, adhesion, or pressure welding. Effect of the Invention

[0022] According to the present invention, it is possible to provide an asymmetrically curved type catheter in which the distal portion of the catheter can be curved to either one side or the other, and the curved shapes are different, so that the distal portion of the catheter can be easily delivered to the desired position. [Brief description of the drawings]

[0023] [Figure 1] 1 illustrates a plan view of a catheter according to an embodiment of the present invention. [Diagram 2] 1 illustrates a plan view of a catheter according to an embodiment of the present invention. [Diagram 3] 1 illustrates a plan view of a catheter according to an embodiment of the present invention. [Figure 4] 3 illustrates a longitudinal cross-sectional view of the distal portion of the catheter shown in FIG. 2. [Diagram 5] 5 shows a VV cross-sectional view of the distal portion of the catheter shown in FIG. 4. [Figure 6] 6 shows a cross-sectional view of the distal portion of the catheter shown in FIG. 4 taken along the line VI-VI. [Figure 7] 7 shows a cross-sectional view of the distal portion of the catheter shown in FIG. 4 taken along line VII-VII. [Figure 8] 5 shows a side view of the inside of the shaft of part A of the distal portion of the catheter shown in FIG. 4. [Figure 9] FIG. 2 illustrates a side view of a first coil according to an embodiment of the present invention. [Figure 10] FIG. 10 is a side view of the first coil shown in FIG. 9 at maximum compression. [Figure 11] FIG. 4 illustrates a side view of a first coil according to another embodiment of the present invention. [Figure 12] 13 illustrates a longitudinal cross-sectional view of a distal portion of a catheter according to another embodiment of the present invention. [Figure 13] 13 illustrates a longitudinal cross-sectional view of a distal portion of a catheter according to yet another embodiment of the present invention. [Figure 14] This shows the method for measuring stiffness. [Figure 15] 5 illustrates another example of a VV cross-sectional view of the distal portion of the catheter shown in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments, and can be modified as appropriate within the scope of the above and below, and all of these are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, the specification and other drawings should be referred to. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, since priority is given to helping understand the features of the present invention.

[0025] The catheter of the present invention comprises: a shaft having a distal end and a proximal end and having a lumen extending in a longitudinal direction; a first wire and a second wire having a distal end and a proximal end, the distal end being fixed to the distal end of the shaft and the proximal end being disposed at the proximal end of the shaft, the first wire and the second wire extending in the lumen of the shaft; a leaf spring disposed in the lumen of the shaft so as to longitudinally separate the lumen of the shaft into a first portion in which the first wire is disposed and a second portion in which the second wire is disposed; and a leaf spring having a lumen extending in the longitudinal direction and in which the first wire and the second wire are disposed, the proximal end of the leaf spring being fixed and proximal to the leaf spring. a support member disposed on the distal end of the support member, the support member having an inner cavity in which a first wire is disposed, and a first coil disposed within the first portion distal to the distal end of the support member, the first coil being fixed at at least two points on the proximal end side of the leaf spring, the first coil having a first fixed portion at which the first coil and the leaf spring are fixed, a second fixed portion located proximal to the first fixed portion at which the first coil and the leaf spring are fixed, and an intermediate non-fixed portion located between the first fixed portion and the second fixed portion and not fixed to the leaf spring, the first coil having a total length L1 in a natural state and a total length L2 at a maximum compression C1 and L C1 / L1 is 0.9 or more and the first coil.

[0026] With the above configuration, the catheter of the present invention can be an asymmetrically curved catheter in which the catheter distal portion can be curved to both one side and the other side of the leaf spring in the radial direction of the shaft, and the curved shape when curved to one side of the leaf spring is different from the curved shape when curved to the other side of the leaf spring. Therefore, the catheter of the present invention can easily deliver the catheter distal portion to a desired position in a blood vessel or the heart. The different curved shapes refer to the shape when curved to one side and the shape when curved to the other side being different, and include the size of the circle along which the curved shape follows, in other words, the radius being different. According to the present invention, the difference in the curved shape between the curved shape on one side and the curved shape on the other side can be made larger, particularly the difference in size, so that it can accommodate various curves of blood vessels.

[0027] A catheter according to an embodiment of the present invention will be described below with reference to Figs. 1 to 15. Figs. 1 to 3 show plan views of a catheter according to an embodiment of the present invention, and the dotted lines show the state when the catheter distal part is curved toward one side and the other side of the leaf spring in the radial direction of the shaft. The dotted lines in Fig. 2 show the state when the catheter distal part is curved further than the case shown in Fig. 1. The dotted lines in Fig. 3 show the state when the catheter distal part is curved further than the case shown in Fig. 2. Fig. 4 shows a longitudinal cross-sectional view of the distal part of the catheter shown in Fig. 2, and the dotted lines show the state when the catheter distal part is curved toward one side and the other side of the leaf spring in the radial direction of the shaft. Figs. 5 to 7 show the VV cross-sectional view, the VI-VI cross-sectional view, and the VII-VII cross-sectional view of the catheter distal part shown in Fig. 4, respectively. Fig. 8 shows a side view of the first wire and the second wire, the leaf spring, the support member, and the first coil arranged in the shaft lumen in part A of the catheter distal part shown in Fig. 4. FIG. 9 shows a side view of the first coil according to one embodiment of the present invention in a natural state, and FIG. 10 shows a side view of the first coil shown in FIG. 9 at maximum compression. FIG. 11 shows a side view of the first coil according to another embodiment of the present invention in a natural state. FIG. 12 shows a longitudinal cross-sectional view of the distal part of the catheter according to another embodiment of the present invention, and the dotted lines show the state when the distal part of the catheter is bent to one side and the other side of the leaf spring in the radial direction of the shaft. FIG. 13 shows a longitudinal cross-sectional view of the distal part of the catheter according to yet another embodiment of the present invention, and the dotted lines show the state when the distal part of the catheter is bent to one side and the other side of the leaf spring in the radial direction of the shaft. FIG. 14 shows a method for measuring the stiffness. FIG. 15 shows another example of a VV cross-sectional view of the distal part of the catheter shown in FIG. 4.

[0028] In the present invention, the proximal side refers to the side of the user's hand with respect to the extending direction of the shaft, and the distal side refers to the opposite side of the proximal side, i.e., the side of the subject of treatment. The extending direction of the shaft is also referred to as the longitudinal direction d. L The radial direction d RThe radial direction d of the shaft is perpendicular to the extending direction of the shaft. In Figs. 1 to 4, 8, 12, and 13, the lower side of the figure is the proximal side, and the upper side of the figure is the distal side. Also, in Figs. 1 to 4, 8, 12, and 13, the left side of the figure is the radial direction d of the shaft. R The right side of the figure is the radial direction d of the shaft. R This is the other side of the leaf spring.

[0029] As shown in FIGS. 1 to 3, the catheter 1 has a distal end and a proximal end, and extends in a longitudinal direction d L The catheter has a shaft 2 having a lumen extending therethrough. A tip 20 is preferably disposed at the distal end of the shaft 2, and a handle 7 is preferably disposed at the proximal end of the shaft 2.

[0030] The shaft 2 is inserted into the body from the distal end and delivered to the treatment site. For this reason, it is preferable that the shaft is flexible, and metal or resin can be used as the material. Since it is inserted into the body, it is preferable to use a biocompatible material. Treatment devices such as electrodes and sensors can be placed on the surface of the shaft 2. By providing electrodes on the surface of the shaft 2, it can be used as an electrode catheter that measures cardiac potentials or an ablation catheter that cauterizes tissue.

[0031] In the inner cavity of the shaft 2, an internal structure for bending the catheter, or a device for treatment or its internal structure, such as a sensor or a lead wire, can be placed. The inner cavity of the shaft 2 may be a single lumen, or may partially have multiple lumen. The structure for bending of the present invention is placed in the single lumen. For example, in order to bend the shaft distal portion 2D of the catheter 1, the portion to be bent can be a single lumen, and the lumen proximal to that can be multiple. The lumen may have a double structure. In the longitudinal direction d of the shaft L The length, outer diameter, thickness, etc. of the catheter can be selected to be an appropriate size for treatment.

[0032] A tip portion 20 is preferably disposed at the distal end of the shaft 2. The tip portion 20 may be a separate member from the shaft 2, or may be the same member as the shaft 2. When the tip portion 20 is a separate member from the shaft 2, the tip portion 20 may include a portion that is inserted into the inner cavity of the shaft 2 or a portion that protrudes distally from the distal end of the shaft. When the tip portion 20 is the same member as the shaft 2, the tip portion 20 may be formed by sealing the opening at the distal end of the shaft 2 by heat fusion or the like of the distal end portion of the shaft 2.

[0033] A handle 7 is preferably disposed on the proximal side of the shaft 2, and the proximal end of the shaft 2 is preferably fixed inside the handle 7. Conductive wires and operating wires extending from the inner cavity of the shaft 2 are disposed inside the handle 7. The handle 7 may include a wire operating unit 70 to facilitate operating the operating wire. By fixing the proximal end of the operating wire to the wire operating unit 70, the wire operating unit 70 can be operated to pull the wire, etc., and bend the distal end of the catheter 1.

[0034] As shown in FIGS. 4 to 7, the catheter 1 has a distal end and a proximal end in the inner cavity of the shaft 2, the distal end is fixed to the distal end of the shaft 2, for example, the tip portion 20, and the proximal end is disposed in the proximal end of the shaft 2, for example, the handle 7, and includes a first wire 41 and a second wire 42 extending in the inner cavity of the shaft 2 (for example, extending from the tip portion 20 to the handle 7), and the first wire 41 and the second wire 42 extend in the inner cavity of the shaft 2 (for example, extending from the tip portion 20 to the handle 7). L The leaf spring 30 is arranged to separate the inner cavity of the shaft 2 into a first portion 21 in which a first wire 41 is arranged and a second portion 22 in which a second wire 42 is arranged, and has a distal end and a proximal end, and is extended in a longitudinal direction d. L and a support member 60, which has an inner cavity extending from the leaf spring 30 to the proximal side of the leaf spring 30 and in which the first wire 41 and the second wire 42 are arranged, and to which the proximal end of the leaf spring 30 is fixed and which is arranged proximally of the leaf spring 30.

[0035] The first wire 41 and the second wire 42 are operation wires for bending and operating the shaft distal portion 2D of the catheter 1. The first wire 41 and the second wire 42 are disposed in the lumen of the shaft 2, and it is preferable that the distal end is fixed to the tip portion 20 and the proximal end is fixed to the handle 7. As the first wire 41 and the second wire 42, a metal wire such as stainless steel or a wire made of a synthetic resin such as a fluororesin can be used. The first wire 41 and the second wire 42 may each be a single wire or may have a structure made of multiple wires.

[0036] The leaf spring 30 is a member that determines the bending direction of the catheter 1, and is provided in the inner cavity of the shaft 2 in the longitudinal direction d. L 2, the first wire 41 is disposed in a first portion 21 and the second wire 42 is disposed in a second portion 22, so as to separate the inner cavity of the shaft 2 into a first portion 21 in which the first wire 41 is disposed and a second portion 22 in which the second wire 42 is disposed. The proximal end of the leaf spring 30 is fixed to the support member 60. The distal end of the leaf spring 30 is preferably fixed to the distal end of the shaft 2. When the tip portion 20 is provided at the distal end of the shaft 2, it is preferably fixed to the tip portion 20. The distal end of the leaf spring 30 does not have to be fixed. The distal end and the proximal end of the leaf spring 30 may be fixed by fixing the ends not directly but by fixing the vicinity of the ends. The method of fixing the distal end and the proximal end of the leaf spring 30 is not particularly limited, but may be, for example, brazing with solder or the like, welding, bonding with an adhesive, connection by crimping, or the like. When the tip portion 20 and the support member 60 are made of metal, they are preferably fixed by laser welding.

[0037] The leaf spring 30 has a distal end and a proximal end and extends in a longitudinal direction d. LThe leaf spring 30 is preferably disposed along the longitudinal axis of the shaft 2. As a result, the leaf spring 30 divides the inner cavity of the shaft 2 into two parts, a first portion 21 on one side including the longitudinal axis of the shaft 2 and a second portion 22 on the other side. The first wire 41 is disposed in the first portion 21 on one side of the divided inner cavity of the shaft 2, and the second wire 42 is disposed in the second portion 22 on the other side. The surface of the leaf spring 30 on the side where the first wire 41 is disposed is referred to as the first surface 31, and the surface of the leaf spring 30 on the side where the second wire 42 is disposed is referred to as the second surface 32. The first surface 31 of the leaf spring 30 can be referred to as one surface, and the second surface 32 can be referred to as the other surface.

[0038] The leaf spring 30 is a spring using a plate material, and examples of the material constituting the leaf spring 30 include metals such as stainless steel, titanium, carbon steel, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy. Alternatively, examples of the material constituting the leaf spring 30 include synthetic resins such as aromatic polyether ketone resin (e.g., PEEK), polycarbonate resin, and fiber-reinforced resin. Alternatively, the leaf spring 30 may be made of synthetic rubbers such as butadiene rubber, isoprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, acrylic rubber, and silicone rubber, or natural rubber. Among these, the material of the leaf spring 30 is preferably stainless steel.

[0039] The support member 60 is disposed proximal to the leaf spring 30 in the inner cavity of the shaft 2, and the first wire 41 and the second wire 42 are disposed in the inner cavity. The proximal end of the leaf spring 30 is fixed to the distal end of the support member 60. The proximal end of the support member 60 may extend to the proximal end of the shaft 2, or may be disposed midway along the shaft 2. The support member 60 may be switched to a different member, such as a tube, midway along the shaft 2.

[0040] The support member 60 may be a proxy tube having a cylindrical shape. If the support member 60 is a proxy tube, the proxy tube receives the proximal end of the leaf spring 30, and a part of the leaf spring 30 can be disposed in the inner cavity of the proxy tube. This makes it possible to firmly fix the leaf spring 30 and the support member 60.

[0041] The support member 60 is preferably flexible like the shaft 2, and may be made of a metal or resin. In particular, it is preferably a coil made of wound metal wire. Since the internal structure of the catheter 1 of the present invention changes at the distal end of the support member 60, it is preferable to select the size, flexibility, and material of the support member 60 so that the change in hardness of the catheter 1 between the distal side and the proximal side of the distal end of the support member 60 is not large.

[0042] The catheter 1 of the present invention can be curved in the section from where the leaf spring 30 is exposed from the distal end of the support member 60 to where the leaf spring 30 is fixed to the distal end of the shaft 2, for example, the tip portion 20. Therefore, the length of the curved portion of the catheter 1 can be appropriately set depending on the length of the leaf spring 30 and the position where the tip portion 20 or the support member 60 is fixed to the leaf spring 30. It is preferable that the support member 60 does not easily deform as the leaf spring 30 is curved.

[0043] As shown in FIG. 4, the catheter 1 has an inner cavity in which the first wire 41 is disposed, and includes a first coil 51 disposed distal to the distal end of the support member 60. The first coil 51 is disposed on the proximal end side of the leaf spring 30 and fixed at least two points on the proximal end side of the leaf spring 30. Disposed on the proximal end side of the leaf spring 30 means that it is disposed in a portion close to the proximal end of the leaf spring, and that the proximal end of the first coil 51 is disposed adjacent to or close to the distal end of the support member 60. The first coil 51 is a member that restricts the bending of the leaf spring 30 toward the one surface 31 side, so if the first coil 51 is fixed to the distal side of the leaf spring 30, the leaf spring 30 cannot bend toward the one surface 31 side. The first coil 51 has a first fixed portion 511, which is the portion where the first coil 51 and the leaf spring 30 are fixed, a second fixed portion 512, which is located proximal to the first fixed portion, and an intermediate non-fixed portion 510m, which is located between the first fixed portion 511 and the second fixed portion 512 and is not fixed to the leaf spring 30.

[0044] The first coil 51 can be made of a metal wire such as stainless steel or nickel-titanium alloy, or a synthetic resin wire such as aromatic polyetherketone resin (e.g., PEEK) or polycarbonate resin. The cross-sectional shape of the wire forming the first coil 51 can be circular, rectangular, or a combination thereof. In particular, the first coil 51 is preferably a metal coil using stainless steel wire having a circular cross section. The wire diameter, coil diameter, and length of the first coil 51 can be appropriately selected as necessary.

[0045] The first coil 51 and the leaf spring 30 are preferably fixed to each other by welding, soldering, adhesion, or pressure welding. Among these, fixing by welding is preferable. If they are fixed by welding, the first fixing portion 511 and the second fixing portion 512 can be formed without using materials such as solder or adhesive.

[0046] The first coil 51 and the leaf spring 30 may be fixed directly to each other, fixed by a proximal end of the first coil 51 being in contact with the support member 60, or indirectly fixed to the first coil 51 and the leaf spring 30 by fixing the first coil 51 to the support member 60 by welding, soldering, bonding, or pressure welding. The second fixing portion 512 may be a fixing portion fixed by a proximal end of the first coil 51 being in contact with the support member 60, or may be indirectly fixed to the first coil 51 and the leaf spring 30 by fixing the first coil 51 to the support member 60 by welding, soldering, bonding, or pressure welding.

[0047] The longitudinal direction d of the first fixing portion 511 and the second fixing portion 512 LThe positions of the first coil 51 and the second coil 512 are not particularly limited, and may be located anywhere on the surface of the first coil 51. For example, the first coil 51 may be located at the distal end of the first coil 51, and the second coil 512 may be located at the proximal end of the first coil 51. Although not shown, the first coil 51 may have a further fixing part in addition to the first coil 511 and the second coil 512. The total number of fixing parts is two or more, and the first coil 51 may have more than two fixing parts. By providing at least two fixing parts, the first coil 51 can be fixed to the leaf spring 30 such that the leaf spring 30 on the proximal side is not curved from the most distal fixing part to the one surface 31 side. In order to prevent the difference in rigidity between the part of the shaft 2 where the first coil 51 is located and the other parts from becoming too large, it is preferable to provide two fixing parts.

[0048] The longitudinal direction d of the fixing portion of the first coil 51 and the leaf spring 30 including the first fixing portion 511 and the second fixing portion 512 L The length in the longitudinal direction d of the fixing part can be set appropriately. L The length in the longitudinal direction d of the fixing portion is preferably short, and as shown in FIG. L If the length is too long, the catheter 1 may lose flexibility when bending toward the other surface 32 side.

[0049] As shown in FIGS. 9 and 10, the first coil 51 has a total length L1 in a natural state and a total length L2 in a maximum compressed state. C1 The ratio is L C1 / L1 is 0.9 or more. The first coil 51 is preferably uncompressed as shown in Fig. 11. In the present invention, an uncompressed coil is a tightly wound coil, i.e., a coil that is wound in the longitudinal direction d L A coil that is not compressed to the maximum, and the total length L1 of the coil in its natural state and the total length L of the coil at its maximum compression C1 Compared to L C1 / L1 is 1, but L C1 When / L1 is 0.9 or more, or 0.95 or more, the coil is substantially uncompressed and is included in the uncompressed coil.C1 It is preferable that / L1 is 0.95 or more.

[0050] By adopting the configuration of the present invention, the catheter 1 can bend the shaft distal portion 2D to either one side or the other side, and the respective curved shapes can be different. In particular, the respective curved diameters can be different, and further, the degree of difference in the curved diameters can be strictly controlled. When the first wire 41 arranged in the first portion 21 of the lumen of the shaft 2, in other words, the first wire 41 arranged on the one surface 31 side of the leaf spring 30, is pulled, the leaf spring 30 curves toward the one surface 31 side, and accordingly the shaft distal portion 2D of the catheter 1 curves toward the one surface 31 side. Since the first coil 51 is fixed to the leaf spring 30 at at least two points on the proximal side of the leaf spring 30 and is an uncompressed coil, the first coil cannot be curved toward the side where the leaf spring 30 is not present, that is, toward the one surface 31 side. Because the uncompressible coil is fixed at two points, the first coil 51 cannot be compressed between the two points when bent in one direction, and functions and behaves as a rigid tube. Therefore, only the portion of the leaf spring 30 between the portion fixed to the tip portion 20 and the fixed portion on the most distal side of the first coil 51 can be bent in one direction.

[0051] If the leaf spring 30 and the first coil 51 were fixed at only one point, the first coil 51 would be able to bend toward the one surface 31 as the leaf spring 30 bends. If the first coil 51 was not an incompressible coil, the coil would be able to expand toward both the one surface and the other surface, and would be able to bend toward the one surface. Therefore, even if the first coil 51 is not fixed to the leaf spring 30 at two points or is not incompressible, the leaf spring 30 would be able to bend toward the one surface 31 in the range from the distal side to the proximal side.

[0052] On the other hand, when the second wire 42 disposed in the second portion 22 of the lumen of the shaft 2 of the catheter 1, in other words, the second wire 42 disposed on the other side 32 of the leaf spring 30, is pulled, the leaf spring 30 bends toward the other side 32, and the shaft distal portion 2D of the catheter 1 bends toward the other side 32. The first coil 51 disposed on the one side 31 of the leaf spring 30 can bend toward the other side 32, following the bending of the leaf spring 30 on the other side 32, by increasing the spacing of the coil wires in the non-fixed portion on the one side of the coil. Therefore, the leaf spring 30 can bend toward the other side 32 in the entire portion between the portion fixed to the tip portion 20 and the distal end of the support member 60.

[0053] The portion where the first coil 51 and the leaf spring 30 are fixed is preferably located on the surface of the first coil 51 facing the one surface 31 of the leaf spring 30. This allows the first coil 51 to bend toward the leaf spring 30, i.e., toward the other surface 32, without being hindered.

[0054] The intermediate non-fixed portion 510m, which is a portion of the first coil 51 between the first fixed portion 511 and the second fixed portion 512, is L In the case where the intermediate non-fixed portion 510m has a plurality of intermediate non-fixed portions 510m, the length of the intermediate non-fixed portion 510m in the longitudinal direction d of the longest intermediate non-fixed portion 510m is preferably 50% or more of the total length L1 of the first coil 51 in the natural state. L It is preferable that the length of the intermediate non-fixed portion 510m in its natural state is 50% or more of the total length L1 of the first coil 51 in its natural state. By ensuring a long intermediate non-fixed portion 510m, it is possible to prevent the first coil 51 from bending toward the one surface 31 while not hindering bending toward the other surface 32. The length of the longest intermediate non-fixed portion 510m of the first coil 51 is LThe length in the natural state of the first coil 51 may be 30% or more, or may be 20% or more, of the total length L1 of the first coil 51 in the natural state. Even in such a range, it is possible to prevent the first coil 51 from bending toward the one surface 31 while not hindering bending toward the other surface 32. In particular, when the fixed portion on the distal side of the longest intermediate non-fixed portion 510m is close to the distal side of the first coil 51, the longitudinal direction d of the longest intermediate non-fixed portion 510m is L Even if the length of the first coil 51 in its natural state is less than 50% of the total length L1 of the first coil 51 in its natural state, bending of the first coil 51 towards the one surface 31 can be effectively prevented.

[0055] It is possible to control the curved shape of the curved portion on the distal side of the catheter 1 by controlling the position of the fixing portion of the first coil 51. This is because the curve toward one side 31 is formed by the portion between the fixing point of the distal end of the shaft 2 of the first wire 41 and the fixing portion on the most distal side of the first coil 51, and the curve toward the other side 32 is formed by the portion from the fixing point of the distal end of the shaft 2 of the second wire 42 to the distal end of the support member 60.

[0056] It is preferable that the first coil 51 does not have a fixing portion between the distal end of the first coil 51 and the first fixed portion 511, which fixes the first coil 51 and the leaf spring 30. By having such a distal non-fixed portion 510d between the distal end of the first coil 51 and the most distal fixed portion, it is possible to prevent the shape of the curve from changing drastically between the bendable portion distal to the first coil 51 and the portion proximal to the most distal fixed portion of the first coil 51 that does not bend toward the one surface 31 side. For example, if the most distal fixed portion of the first coil 51 is at the distal end of the first coil 51, there is a risk that the catheter 1 will break at the distal end of the first coil 51.

[0057] 12, the catheter 1 may further include a second coil 52. The second coil 52 has an inner cavity in which the first wire 41 is disposed, and is a first portion 21 partitioned by the leaf spring 30 in the inner cavity of the shaft 2, and is disposed distal to the first coil 51. The second coil 52 may be in contact with any part of the leaf spring 30 or the like in the inner cavity of the shaft 2, but is preferably not fixed to any part.

[0058] 12, the catheter 1 may further include a third coil 53. The third coil 53 has an inner cavity in which the second wire 42 is disposed, and is disposed in the second portion 22 partitioned by the leaf spring 30 in the inner cavity of the shaft 2. The third coil 53 may be in contact with any part of the leaf spring 30 or the like within the inner cavity of the shaft 2, but is preferably not fixed to any part.

[0059] Although not shown, similar to the first coil 51 shown in FIGS. 9 and 10, the second coil 52 has a total length L2 in the natural state and a total length L3 at the maximum compression. C2 L C2 / L2 is more preferably smaller than 0.9, and L C1 Similarly, the third coil 53 has a total length L3 in the natural state and a total length L4 in the maximum compressed state. C3 L C3 / L3 is more preferably smaller than 0.9, and L C1 It is preferable that the total length L1 of the first coil 51 in the natural state and the total length L C1 Compared to L C1 / L1 is the ratio L C2 / L2 and L C3 If it is equal to or smaller than / L3, the first coil 51 will be equally or more easily deformed than the second coil 52 and the third coil 53, making it difficult to control the curved shape of the catheter 1.

[0060] The lengths of the first coil 51, the second coil 52, and the third coil 53 can be appropriately selected according to the shape of the curve required in the catheter 1. The first wire 41 and the second wire 42 may be partially exposed between the tip portion 20 and the support member 60 as shown in FIG. 12, or may be entirely disposed in the lumen of the first coil 51, the second coil 52, and the third coil 53 as shown in FIG. 13. For example, the first coil 51 and the third coil 53 can be disposed so as to be in contact with the support member 60. Alternatively, the first coil 51 and the third coil 53 may be disposed at a slight distance from the support member 60, and the first wire 41 and the second wire 42 may be exposed. This also applies to the relationship between the tip portion 20 and the second coil 52 and the third coil 53. Similarly, the first coil 51 and the second coil 52 may be in contact with each other or may have a gap therebetween.

[0061] As shown in FIG. 9, the first coil 51, the second coil 52, and the third coil 53 are made of coil wire wound in a spiral shape. The pitch intervals of the first coil 51, the second coil 52, and the third coil 53 can be set appropriately. Here, the coil pitch interval is the interval between the center points of adjacent coil wires forming the coil. The pitch interval can be measured as the pitch interval P1 of the first coil 51 shown in FIG. 9. When the pitch interval is larger than the thickness of the coil filaments, gaps are created between the coil filaments, and the coil can be compressed. At this time, the total length L of the coil in its natural state and the total length L of the coil when it is fully compressed are C Ratio of L C / L is smaller than 1. Therefore, in the present invention, L C / L is approximately equal to coil wire diameter / pitch spacing. L of the first coil 51 C1 When / L1 is 0.9 or more, the coil wire diameter / pitch interval of the first coil 51 is 0.9 or more.

[0062] When the catheter 1 includes the second coil 52 or the third coil 53, the coil wire diameter and coil diameter of the second coil 52 and the third coil 53 can be appropriately selected according to the required curved shape of the catheter 1. As mentioned above as the material of the first coil, the material constituting the second coil 52 and the third coil 53 can be metal or resin. The total length L of the coil in the natural state and the total length L of the coil when maximally compressed can be changed not only by the pitch interval but also by the coil wire diameter, coil diameter, material, etc. of the coil. C It is possible to control the above.

[0063] When the catheter 1 includes the second coil 52 or the third coil 53, it is preferable that the pitch interval P1 of the first coil 51 is smaller than the pitch interval of the second coil 52 or the pitch interval of the third coil 53. By setting the pitch interval in this manner, the total length L of the coil in the natural state and the total length L of the coil at the maximum compression are C Adjust the L C2 / L2 and L C3 / L3 to L C1 It can be made smaller than / L1.

[0064] In particular, when the catheter 1 includes the second coil 52, it is preferable that the pitch interval P1 of the first coil 51 is smaller than the pitch interval of the second coil 52. In this case, it is preferable that the coil wire diameter and the coil diameter of the first coil 51 are the same as the coil wire diameter and the coil diameter of the second coil 52. The coil wire diameter is the diameter of the wire forming the coil, and the coil diameter is the diameter of the coil. This makes it possible to balance the size of the internal structure of the shaft 2, and also makes it possible to make the rigidity of the first coil 51 and the second coil 52 close to each other when curved toward the other surface 32, so that the curved shape toward the other surface 32 can be made closer to a circle.

[0065] The pitch interval of the second coil 52 may be the same as or different from the pitch interval of the third coil 53. The pitch interval of the second coil 52 and the pitch interval of the third coil 53 may be such that the coils are not completely compressed when the catheter 1 is bent to the maximum extent. Due to the presence of the first coil 51, the curvature diameter of the catheter 1 toward the one surface 31 side is smaller than the curvature diameter of the catheter 1 toward the other surface 32 side, and the second coil 52 is shorter than the third coil 53. Since the second coil 52 is shorter than the third coil 53, the second coil 52 is more likely to be completely compressed. From this point of view, it is preferable to set the pitch interval of the second coil 52 wider. The coil wire diameter and coil diameter of the second coil 52 may be the same as or different from the coil wire diameter and coil diameter of the third coil 53, but are preferably the same. By making the pitch interval of the second coil 52 different from the pitch interval of the third coil 53, the shape of the curvature of the catheter 1 toward the one surface 31 side and the shape of the curvature of the catheter 1 toward the other surface 32 side can be made more different. The coil wire diameter and coil diameter of the first coil 51 may be the same as those of the second coil 52 and the third coil 53, or may be different.

[0066] The bending rigidity of the first coil 51 is greater than that of the second coil 52, and the difference between the bending rigidity of the first coil 51 and the bending rigidity of the second coil 52 is preferably 50% or less. This allows the shape of the curve when the shaft distal portion 2D curves toward one surface 31 of the leaf spring 30 to be a smooth curve. Methods for adjusting the rigidity include selecting the type and amount of wire constituting each coil, adjusting the inner and outer diameters of each coil, adjusting the pitch interval of each coil, and the like.

[0067] The rigidity can be obtained by a three-point bending test as shown in Fig. 14. The three-point bending test was performed in accordance with JIS K7171. A rigidity measurement sample 603 was placed on two supports 602 arranged on a support table 601 at a distance D between the supports, and a load F was measured when an indenter 604 arranged at the center of the distance D between the supports was moved a certain distance in the vertical direction. This load F was taken as the rigidity of the rigidity measurement sample 603.

[0068] 1 to 4, the catheter 1 having the above configuration can have a curved shape when the shaft distal portion 2D is curved toward one surface 31 of the leaf spring 30 different from a curved shape when the shaft distal portion 2D is curved toward the other surface 32 of the leaf spring 30 by the first coil 51. Preferably, the curved diameter d1 when the shaft distal portion 2D is curved toward one surface 31 of the leaf spring 30 can be made smaller than the curved diameter d2 when the shaft distal portion 2D is curved toward the other surface 32 of the leaf spring 30. Here, the curved diameter d1 is the diameter of a circumscribed circle of the outer surface of the shaft distal portion 2D curved toward the first wire 41 side of the shaft distal portion 2D curved toward the one surface 31 of the leaf spring 30, and is the diameter of the circle when the curve of the shaft distal portion 2D is a part of an arc. The curved diameter d2 is the diameter of a circumscribing circle of the outer surface of the shaft distal portion 2D on the second wire 42 side curved toward the other surface 32 of the leaf spring 30, and is the diameter of the circle when the curve of the shaft distal portion 2D is a part of an arc. The circumscribing circle of the curved shape does not necessarily have to be a perfect circle. Depending on the state of curvature, the curved shape may be a shape on the circumscribing circle or a combination of straight lines and curves rather than an arc. In any case, the catheter 1 of the present invention can have different shapes of curvature on the one surface 31 side and the other surface 32 side by using the first coil 51.

[0069] As shown in FIG. 15, the catheter 1 further includes a protective tube 80 having an inner cavity and disposed in the inner cavity of the shaft 2, and the leaf spring 30, the first coil 51, the second coil 52, and the third coil 53 are preferably disposed in the inner cavity of the protective tube 80. The protective tube 80 can be formed using a material similar to that used to form the shaft 2. The protective tube 80 can protect the leaf spring 30, the first coil 51, the second coil 52, and the third coil 53, as well as the first wire 41 and the second wire 42. The protective tube 80 may be in contact with any of the points, but is preferably fixed to the support member 60. This allows the protective tube 80 to prevent the coils from moving within the shaft 2.

[0070] This application claims the benefit of priority based on Japanese Patent Application No. 2020-97338, filed on June 4, 2020. The entire contents of the specification of Japanese Patent Application No. 2020-97338, filed on June 4, 2020, are incorporated by reference into this application. [Explanation of symbols]

[0071] 1: Catheter 2: Shaft 2D: Distal shaft 7: Handle 20:Tip 21: Part 1 22: Part 2 30: Leaf spring 31: One side of the leaf spring 32: The other side of the leaf spring 41: First wire 42: Second wire 51: First coil 52: Second coil 53: Third coil 60: Support member 70: Wire operation unit 80: Protective tube 510d: Distal non-fixed part 510m: Intermediate non-fixed part 511: 1st fixed part 512:Second fixed part 601: Support stand 602:Fulcrum 603: Stiffness measurement sample 604: Indenter d1: Curvature diameter when the leaf spring is bent to one side d2: Curvature diameter when the leaf spring is bent to the other side d L : Longitudinal direction d R :radial direction D: Distance between supports F: Load L1: Total length of the first coil in its natural state L C1 : Total length of the first coil at maximum compression P1: Pitch spacing of the first coil

Claims

1. a shaft having a distal end and a proximal end and having a longitudinally extending lumen; a first wire and a second wire having a distal end and a proximal end, the distal end being fixed to the distal end of the shaft, the proximal end being disposed at the proximal end of the shaft, and extending into a lumen of the shaft; a leaf spring disposed in the inner cavity of the shaft so as to separate the inner cavity of the shaft in the longitudinal direction into a first portion in which the first wire is disposed and a second portion in which the second wire is disposed; a support member extending in the longitudinal direction, having an inner cavity in which the first wire and the second wire are disposed, to which a proximal end of the leaf spring is fixed, and disposed proximally of the leaf spring; a first coil having an inner lumen in which the first wire is disposed; the first coil is disposed within the first portion distal to a distal end of the support member and not within the second portion; The first coil is fixed to the proximal end side of the leaf spring at at least two points, and has a first fixed portion where the first coil and the leaf spring are fixed, a second fixed portion located proximal to the first fixed portion where the first coil and the leaf spring are fixed, and an intermediate non-fixed portion located between the first fixed portion and the second fixed portion and not fixed to the leaf spring, The first coil has a total length L １ and the total length L at maximum compression Ｃ１ and L Ｃ１ / L １ and the first coil is 0.9 or greater.

2. The catheter of claim 1 , wherein the support member is a tube or a coil.

3. 3. The catheter of claim 1, wherein the first coil is non-compressible.

4. The catheter according to any one of claims 1 to 3, wherein the portion where the first coil and the leaf spring are fixed is located on a surface of the first coil facing one side of the leaf spring.

5. The non-fixed portion of the first coil, which has the longest length in the longitudinal direction, has a length in the longitudinal direction in a natural state that is equal to or smaller than the total length L of the first coil in the natural state. １ The catheter according to any one of claims 1 to 4, wherein the thickness is 50% or more.

6. The catheter according to any one of claims 1 to 5, wherein the first coil further has a distal non-fixed portion between a distal end of the first coil and the first fixed portion, the distal non-fixed portion not having a fixed portion for fixing the first coil and the leaf spring.

7. The catheter according to any one of claims 1 to 6, further comprising a second coil, the second coil having an inner lumen in which the first wire is disposed, and disposed within the first portion and distal to the first coil.

8. The second coil has a total length L ２ and the total length L at maximum compression Ｃ２ and the ratio L Ｃ２ / L ２ The catheter of claim 7, wherein is less than 0.

9.

9. 9. The catheter according to claim 7, wherein the bending rigidity of the first coil is greater than the bending rigidity of the second coil, and the difference between the bending rigidity of the first coil and the bending rigidity of the second coil is 50% or less.

10. the first coil includes a first coil wire wound in a helical shape; the second coil includes a helically wound second coil wire; The catheter according to any one of claims 7 to 9, wherein the pitch interval of the first coil is smaller than the pitch interval of the second coil.

11. The catheter of claim 10 , wherein a coil wire diameter and a coil diameter of the first coil are the same as a coil wire diameter and a coil diameter of the second coil.

12. The catheter according to any one of claims 1 to 11, further comprising a third coil having an inner lumen in which the second wire is disposed and disposed in the second portion, the third coil having a total length L 3 in a natural state and a total length L C3 at maximum compression, the ratio L C3 / L 3 being less than 0.

9.

13. a second coil, the second coil having an inner lumen in which the first wire is disposed, the second coil being disposed distal to the first coil in the first section; a third coil, the third coil having an inner lumen in which the second wire is disposed, the third coil being disposed in the second portion, the third coil having a total length L3 in a natural state and a total length Lc3 at maximum compression, the ratio Lc3 / L3 being less than 0.9; The catheter according to any one of claims 1 to 12, further comprising a protective tube having an inner lumen and disposed within the inner lumen of the shaft, the protective tube having the leaf spring, the first coil, the second coil, and the third coil disposed within the inner lumen.

14. The catheter according to any one of claims 1 to 13, wherein the first coil is fixed at the first fixing portion and the second fixing portion by welding, soldering, adhesion, or crimping.

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