catheter

Abstract

To provide a catheter capable of easily realizing an intended bent shape by preventing bent torsion and kink of a catheter distal part while preventing interference of a cylindrical part on a wire as a traction member and a plate spring as a bending member when bending the catheter distal part.SOLUTION: A catheter 1 includes: a shaft 2; a coil 50 arranged in the lumen of the shaft 2; a cylindrical part 60 arranged outside the coil 50; one or more wires 30; and a plate spring 40 having a first connection part 41 where a proximal end part is connected to the distal end part of the coil 50, and a second connection part 42 where a distal end part is directly or indirectly fastened to the distal end part of the shaft 2. The distal end of the cylindrical part 60 is in the same position as the distal end of the coil 50 or is positioned at a proximal side from the distal end of the coil 50, and a length from the distal end of the coil 50 to the distal end of the cylindrical part 60 is 30 windings or less of the coil 50.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Catheters are inserted into the heart through arteries during examinations and treatments for heart disease. To deliver the tip of the catheter to the desired location within the heart, the distal portion of the catheter must be bent to follow the blood vessels within the heart. Therefore, catheters have been devised that allow the distal portion to be bent by operating a handle located at the proximal end of the catheter. Generally, the distal portion of a bendable catheter can be bent by pulling a wire fixed inside the tip of the catheter using the handle.

[0003] One such catheter has been proposed, in which the distal end of a leaf spring, which is a component that bends the distal portion of the catheter, and the distal end of a wire are fixed to the distal end of the catheter, and the proximal end of the leaf spring is connected to a tube placed in the lumen of the catheter.

[0004] In order to deliver the tip of a catheter to a desired location according to the size and purpose of the heart, the distal portion of the catheter must be able to bend freely in the desired direction by wire manipulation and move along the tortuous blood vessels (trackability). Furthermore, to prevent the distal portion of the catheter from moving in an undesired direction and damaging the lumen wall of the living body, and to improve the ability of the force generated by manipulation from the proximal side to be transmitted to the distal portion of the catheter (pushability), it is necessary to suppress problems such as twisting and kinking of the distal portion of the catheter when it is bent. For this reason, various configurations have been proposed for fixing the proximal side of the leaf spring, which is a component placed in the distal portion of the catheter and used to bend the distal portion of the catheter.

[0005] In the catheters disclosed in Patent Documents 1 and 2, a wire is disposed within a wire tube, and a leaf spring is disposed within the catheter tube with its proximal end fixed to a coil tube. Of these, Patent Document 2 discloses a catheter in which the wire tube is fixed to the surface of the leaf spring via an adhesive layer. Patent Document 3 discloses a catheter in which the leaf spring is fixed to the coil tube via a coil stopper. Patent Document 4 discloses a catheter in which the wire and leaf spring are disposed within a distal tube, and the proximal end of the leaf spring is fixed to the proximal tube. It also discloses that a protective tube is disposed outside the proximal tube, and the proximal end of the distal tube is distal to the distal end of the protective tube. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-61350 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-200445 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-64614 [Patent Document 4] International Publication No. 2019 / 156059 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in conventional catheters, when a coil is connected to the proximal end of a leaf spring to ensure the rigidity of the base end of the catheter, pulling on the wire compresses the coil, causing it to expand radially, causing the leaf spring connected to the coil to rotate and twist the distal catheter section. To prevent this, fixing the connection between the coil and leaf spring to the catheter tube is considered, but the fixed portion increases in rigidity, creating a rigidity step where the stiffness changes suddenly along the longitudinal axis of the catheter tube. This can lead to kinking, or breaking, of the distal catheter section at the rigidity step when the catheter is bent, leaving room for improvement. Furthermore, there is room for improvement in the fact that the wire, which serves as the traction member, and the leaf spring, which serves as the bending member, are subject to interference from other components, adversely affecting the curved shape of the distal catheter section.

[0008] Interference of other members with the traction member or bending member when bending the distal portion of the catheter, as well as twisting or kinking of the distal portion of the catheter, can lead to reduced pushability, making it difficult to achieve the desired curved shape and resulting in a catheter with reduced trackability. The present invention has been made in view of the above circumstances, and its object is to provide a catheter that can easily achieve the desired curved shape by preventing interference of the tubular part with the wire, which is the traction member, and the leaf spring, which is the bending member, when bending the distal portion of the catheter, while preventing twisting or kinking of the curved distal portion of the catheter. [Means for solving the problem]

[0009] A catheter that can solve the above problem comprises a shaft having a distal end and a proximal end in the longitudinal direction and having a lumen extending in the longitudinal direction, a coil having a lumen extending in the longitudinal direction and disposed in the lumen of the shaft, a tubular portion disposed outside the coil in the lumen of the shaft, and a wire extending in the lumen of the coil or outside the coil and the tubular portion in the lumen of the shaft, the distal side of the wire being directly or indirectly connected to the distal end of the shaft distal to the distal end of the coil. The catheter includes one or more wires disposed inside the shaft, and a leaf spring extending through the lumen of the shaft, the leaf spring having a first connection portion where the proximal end of the leaf spring is directly or indirectly connected to the distal end of the coil, and a second connection portion where the distal end of the leaf spring is fixed directly or indirectly to the distal end of the shaft, the distal end of the tubular portion being located at the same position as the distal end of the coil or more proximal to the distal end of the coil in the longitudinal axis direction, and the length from the distal end of the coil to the distal end of the tubular portion is 30 turns or less of the coil. This configuration prevents interference of the tubular portion with the wires used to pull the catheter distally and the leaf spring that determines the curved shape of the catheter distal portion when bending the catheter distal portion. This allows force from the proximal side to be easily transmitted to the wires disposed in the catheter distal portion, and the bending of the leaf spring caused by pulling the wire is less affected by the tubular portion, resulting in a catheter that is less likely to kink. Furthermore, even if the coil is compressed by pulling the wire, it can be prevented from expanding radially, and twisting of the curved distal section of the catheter due to rotation of the leaf spring connected to the coil can be suppressed. Because the ease with which the coil expands depends on the number of turns of the coil, the above effect can be achieved by ensuring that the length in the longitudinal direction from the distal end of the coil to the distal end of the tubular section is equal to or less than the predetermined number of turns of the coil. As a result, it becomes easier to achieve the desired curved shape of the catheter distal section.

[0010] It is preferable that at least a portion of the inner wall of the cylindrical portion abuts against the outer surface of the coil.

[0011] In the longitudinal direction, the distal end of the tubular portion is preferably located more proximal than the distal end of the coil.

[0012] It is preferable that the first connecting portion is not disposed inside the cylindrical portion in the longitudinal axis direction.

[0013] In the longitudinal direction, the proximal end of the tubular portion is preferably located distal to the proximal end of the coil, and the coil preferably has a first fixing portion fixed to the shaft proximal to the proximal end of the tubular portion. In this case, in the longitudinal direction, the length from the distal end of the first fixing portion to the proximal end of the tubular portion is preferably 20 turns or less of the coil.

[0014] The cylindrical portion preferably has a second fixed portion fixed to the shaft. In this case, the length from the distal end of the second fixed portion to the distal end of the coil in the longitudinal direction is preferably no more than twice the length of the leaf spring. Furthermore, in this case, the distal end of the second fixed portion is preferably located proximal to the proximal end of the first connecting portion in the longitudinal direction, and the length from the distal end of the second fixed portion to the proximal end of the first connecting portion is preferably at least ¼ the length of the leaf spring. [Effects of the Invention]

[0015] According to the present invention, in a catheter having a bendable distal section, interference of the tubular section with the wire and leaf spring can be prevented when bending the catheter distal section. This allows force from the proximal side to be easily transmitted to the wire disposed in the catheter distal section, and the bending of the leaf spring caused by pulling the wire is less affected by the tubular section, making the catheter less prone to kinking. Furthermore, twisting of the bent catheter distal section can be prevented. As a result, a catheter can be provided in which the desired bent shape of the catheter distal section can be achieved by manipulating the wire, and the catheter distal section can be easily delivered to a desired location. [Brief explanation of the drawings]

[0016] [Figure 1] 1 illustrates a plan view of a catheter according to an embodiment of the present invention. [Figure 2]2 is a longitudinal sectional view (partial plan view) of the distal portion of the catheter shown in FIG. 1. [Figure 3] 3 shows a cross-sectional view of the catheter taken along line III-III in FIG. 2. [Figure 4] 4 shows a cross-sectional view of the catheter taken along line IV-IV in FIG. 2. [Figure 5] 3 shows a cross-sectional view of the catheter taken along line VV in FIG. 2. [Figure 6] 6 shows a cross-sectional view of the catheter taken along line VI-VI in FIG. 2. [Figure 7] 1 illustrates a plan view of a coil according to an embodiment of the present invention. [Figure 8] 8 is a plan view of the coil shown in FIG. 7 at maximum compression. [Figure 9] 10 is a longitudinal axial cross-sectional view (partial plan view) of a distal portion of a catheter according to another embodiment of the present invention. FIG. [Figure 10] 10 shows a cross-sectional view of the catheter taken along line XX in FIG. 9. [Figure 11] 11 illustrates another example of the cross-sectional view shown in FIG. 10. [Figure 12] 10 is a longitudinal axial cross-sectional view (partial plan view) of a distal portion of a catheter according to yet another embodiment of the present invention. FIG. [Figure 13] 13 shows a cross-sectional view of the catheter taken along line XIII-XIII in FIG. 12. [Figure 14] 14 illustrates another example of the cross-sectional view shown in FIG. 13. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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 implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience. In such cases, reference should be made to the specification or other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0018] A catheter according to an embodiment of the present invention comprises a shaft having a distal end and a proximal end in the longitudinal direction and having a lumen extending in the longitudinal direction; a coil having a lumen extending in the longitudinal direction and disposed in the lumen of the shaft; a tubular portion disposed outside the coil in the lumen of the shaft; one or more wires extending in the lumen of the shaft within the lumen of the coil or outside the coil and the tubular portion, the distal ends of the wires being connected directly or indirectly to the distal end of the shaft distal to the distal end of the coil; and a leaf spring extending in the lumen of the shaft, the leaf spring having a first connecting portion where the proximal end of the leaf spring is directly or indirectly connected to the distal end of the coil and a second connecting portion where the distal end of the leaf spring is fixed directly or indirectly to the distal end of the shaft, wherein the distal end of the tubular portion is located at the same position as the distal end of the coil or more proximal to the distal end of the coil in the longitudinal direction, and the length from the distal end of the coil to the distal end of the tubular portion is equal to or less than 30 turns of the coil.

[0019] With the above configuration, the catheter according to the embodiment of the present invention can bend the distal catheter section distal to the distal end of the coil by bending the leaf spring connected to the distal end of the shaft by pulling the wire while ensuring rigidity at the proximal end of the catheter using the coil. From the viewpoint of operation, the wire can be considered the pulling member, and the leaf spring can be considered the bending member. By positioning the distal end of the tubular section at the same position as the distal end of the coil or more proximal than the distal end of the coil, interference between the tubular section and the wire, which serves as the pulling member, and the leaf spring, which serves as the bending member, can be prevented. This allows force from the proximal side to be easily transmitted to the wire disposed in the distal catheter section, and the bending of the leaf spring caused by pulling the wire is less affected by the tubular section, resulting in a catheter that is less likely to kink. Furthermore, since the tubular portion is disposed outside the coil and the longitudinal length from the distal end of the coil to the distal end of the tubular portion is equal to or less than 30 coil turns, the tubular portion can be disposed close to the distal end of the coil, which is the base end of the curvature. This prevents the coil from expanding radially even when compressed by pulling the wire, and prevents twisting of the curved distal portion of the catheter due to rotation of the leaf spring connected to the coil. Because the ease of expansion of a coil depends on the number of coil turns, the above effect can be achieved by ensuring that the longitudinal length from the distal end of the coil to the distal end of the tubular portion is equal to or less than the predetermined number of coil turns. As a result, the catheter can achieve the desired curved shape and be easily delivered to the desired location, facilitating examinations and treatments using the catheter and preventing accidents such as the distal catheter portion damaging the lumen wall of a living body or moving in an undesired direction.

[0020] A catheter according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 shows a plan view of a catheter according to an embodiment of the present invention, with the dotted line indicating the state when the distal portion of the catheter is bent toward one side of the leaf spring in the radial direction of the shaft. FIG. 2 shows a longitudinal cross-sectional view of the catheter shown in FIG. 1 when the distal portion is not bent, and is a plan view of the coil only. FIGS. 3 to 6 show cross-sectional views of different positions in the longitudinal direction of the catheter shown in FIG. 2, and are cross-sectional views along line III-III, line IV-IV, line VV, and line VI-VI, respectively. FIG. 7 shows a plan view of a coil according to an embodiment of the present invention, and FIG. 8 shows a plan view of the coil shown in FIG. 7 when it is maximally compressed.

[0021] In the present invention, the proximal side refers to the direction toward the user's hand in the extending direction of the catheter 1, and the distal side refers to the opposite side of the proximal side, i.e., the direction toward the patient to be treated. The extending direction of the catheter 1 is the longitudinal axis direction d of the shaft 2. L It is preferable that the longitudinal axis direction d is the same as L In the cross section perpendicular to the axis, the direction connecting the center of the shaft 2 and a point on the circumscribed circle of the shaft 2 is the radial direction d R In the figures in this specification, the bottom of the figure is the proximal side and the top of the figure is the distal side.

[0022] As shown in FIG. 1, the catheter 1 is L and a distal end and a proximal end in a longitudinal direction d L The device has a shaft 2 with an inner lumen extending from the distal end to the treatment site. The distal end of the shaft 2 is inserted into the body, and by manipulating the proximal end, the distal end is delivered to the treatment site. For this reason, it is preferable that the shaft 2 is flexible, and metal or resin can be used as the material. Because it is inserted into the body, the shaft 2 is preferably made of a biocompatible material.

[0023] Examples of materials constituting the shaft 2 include synthetic resins such as polyolefin resins such as polyethylene and polypropylene; polyamide resins such as nylon; polyester resins such as PET; polyimide resins; aromatic polyether ketone resins such as PEEK; polyether polyamide resins; polyurethane resins; fluorine-based resins such as PTFE, PFA, and ETFE; vinyl chloride resins; and silicone resins, as well as natural rubber. The shaft 2 may have a single-layer structure or a multi-layer structure. When the shaft 2 has a multi-layer structure, for example, the intermediate layer of the resin tube constituting the shaft 2 may be a metal braid made of stainless steel, carbon steel, nickel-titanium alloy, or the like.

[0024] Components for testing and treatment, such as electrodes and sensors, can be arranged on the surface of the shaft 2. Furthermore, components such as an internal structure for bending the catheter distal section 1D and leads connecting to the electrodes and sensors can be arranged in the lumen of the shaft 2. By connecting the distal end of the lead to an electrode provided on the surface of the shaft 2 and connecting the proximal end of the lead to a detector or power source through the proximal side of the catheter 1, it is possible to receive electrical signals from the electrode or to apply electricity to the electrode. With this configuration, the catheter 1 can be used as an electrode catheter for measuring cardiac potentials or an ablation catheter for cauterizing tissue. The longitudinal axis direction d of the shaft 2 L The length, outer diameter, thickness, etc. of the tube can be selected appropriately depending on the intended use.

[0025] 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 formed as part of the same member. 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 lumen of the shaft 2 or a portion that protrudes distally from the distal end of the shaft 2. When the tip portion 20 is formed as part of 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 of the shaft 2.

[0026] A handle 7 is preferably disposed proximal to the shaft 2, and the proximal end of the shaft 2 is preferably fixed inside the handle 7. The proximal end of the wire 30, which will be described later and the lead wires extending from the lumen of the shaft 2, are preferably disposed inside the handle 7. The handle 7 may be provided with a wire manipulation unit 70 to facilitate manipulation of the wire 30. By fixing the proximal end of the wire 30 to the wire manipulation unit 70, the wire manipulation unit 70 can be manipulated to pull or release the wire 30, thereby bending or returning the catheter distal section 1D to its original shape.

[0027] As shown in FIG. 2, the catheter 1 includes a wire 30 extending through the lumen of the shaft 2, a leaf spring 40, and a longitudinal axis d L and a coil 50 having an inner lumen extending from the distal end of the coil 50. The wire 30 is a pulling member, the leaf spring 40 is a bending member, and the coil 50 is a member disposed on the proximal side of the bending. By pulling the wire 30, the leaf spring 40 is bent, and the catheter distal section 1D on the distal side from the distal end of the coil 50 can be bent.

[0028] As shown in FIGS. 2, 5, and 6, the leaf spring 40 has a longitudinal axis d LPreferably, the leaf spring 40 has a plate-like shape extending from the distal end of the coil 50 to the distal end of the coil 50, and has one surface 40a and the other surface 40b. The leaf spring 40 has a plate-like shape, which determines the bending direction of the catheter distal section 1D and allows the catheter distal section 1D to bend toward the one surface 40a and / or the other surface 40b of the leaf spring 40. The leaf spring 40 has a first connection portion 41, where the proximal end of the leaf spring 40 is directly or indirectly connected to the distal end of the coil 50. As shown in FIG. 5, the proximal end of the leaf spring 40 may be fixed to the distal end of the coil 50 by adhesive, soldering, laser welding, or the like, thereby forming the first connection portion 41. Alternatively, although not shown, the proximal end of the leaf spring 40 may be brought into abutting contact with the distal end of the coil 50, thereby forming the first connection portion 41 without using any special fixing means. The first connection portion 41, which connects the proximal end of the leaf spring 40 and the distal end of the coil 50, may not be formed by directly abutting or fixing the respective ends, but may be formed indirectly by abutting or fixing the vicinity of each end.

[0029] The positional relationship between the leaf spring 40 and the coil 50 at the first connection portion 41 may be arbitrary. For example, the proximal end of the leaf spring 40 may be disposed within the lumen of the coil 50 or may be disposed outside the coil 50. Alternatively, the proximal end of the leaf spring 40 may be abutted against or fixed to the distal end of the coil 50. Among these positional relationships, it is particularly preferable that a portion of the proximal end of the leaf spring 40 is disposed within the lumen of the coil 50 at the first connection portion 41, and the coil 50 receives the proximal end of the leaf spring 40. This allows for a stable connection between the leaf spring 40 and the coil 50.

[0030] The leaf spring 40 also has a second connection portion 42 where the distal end of the leaf spring 40 is directly or indirectly fixed to the distal end of the shaft 2. At the second connection portion 42, the distal end of the leaf spring 40 may be directly fixed to the distal end of the shaft 2. Alternatively, the ends of the leaf spring 40 and the shaft 2 may not be directly fixed to each other, but may be fixed to each other by fixing the vicinity of each end. For example, the distal end of the leaf spring 40 may be indirectly fixed to the distal end of the shaft 2, such as by providing a tip portion 20 at the distal end of the shaft 2 and fixing the distal end of the leaf spring 40 to the tip portion 20. The method for fixing the distal end of the leaf spring 40 to the distal end of the shaft 2 is not particularly limited, and examples of such fixing methods include adhesive, soldering, and laser welding.

[0031] The leaf spring 40 is a spring made of a plate material, and examples of materials for the leaf spring 40 include metals such as stainless steel, titanium, carbon steel, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy. Alternatively, the material for the leaf spring 40 may be a synthetic resin such as aromatic polyether ketone resin (e.g., PEEK), polycarbonate resin, or fiber-reinforced resin. Alternatively, the leaf spring 40 may be made of synthetic rubber such as butadiene rubber, isoprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, acrylic rubber, or silicone rubber, or natural rubber. Among these, stainless steel is preferred as the material for the leaf spring 40.

[0032] The wire 30 is a traction member for bending the catheter distal section 1D. By pulling the wire 30 proximally, the leaf spring 40 bends toward the one surface 40a or the other surface 40b, thereby bending the catheter distal section 1D toward the one surface 40a or the other surface 40b. The degree of bending of the leaf spring 40 can be adjusted by adjusting the force pulling the wire 30 proximally. Releasing the pulling force of the wire 30 returns the leaf spring 40 to its original curve, allowing the catheter distal section 1D to return to its original state before bending. For example, by placing the wire 30 on the one surface 40a side of the leaf spring 40, the leaf spring 40 can be bent toward the one surface 40a, and by placing the wire 30 on the other surface 40b side of the leaf spring 40, the leaf spring 40 can be bent toward the other surface 40b. Multiple wires 30 may be arranged; for example, by arranging wires 30 on one side 40a and the other side 40b of the leaf spring 40, it is possible to make the catheter 1 bendable on both the one side 40a and the other side 40b.

[0033] The wire 30 may extend into the lumen of the coil 50 as shown in FIG. 2 , or may extend outside the coil 50 and the tubular portion 60 (described later), although not shown. The distal side of the wire 30 is directly or indirectly connected to the distal end of the shaft 2 distal to the distal end of the coil 50. This allows the catheter distal section 1D to be bent by pulling the wire 30. Of the distal side of the wire 30, the distal end of the wire 30 is preferably connected to the distal end of the shaft 2, or the distal end of the wire 30 may be connected to the distal end of the shaft 2. The distal side of the wire 30 may be connected to the distal end of the shaft 2 by being directly fixed thereto, or may be indirectly connected to the distal end of the shaft 2 by being fixed to the tip section 20 or another member, such as a leaf spring 40, disposed at the distal end of the shaft 2. The distal portion of the wire 30 connected to the distal end of the shaft 2, and the portion of the distal end of the shaft 2 to which the wire 30 is connected, can be selected appropriately depending on the desired curved shape of the catheter distal portion 1D.

[0034] Wire 30 can be made of a metal wire such as stainless steel or a wire made of a synthetic resin such as a fluororesin, and one wire 30 can be a single wire or a structure made of multiple wires. Wire 30 and shaft 2 can be connected by fixing them using a method similar to the method for fixing leaf spring 40 and shaft 2, or they can be connected without using any special fixing means by abutting the distal end of wire 30 against the distal end of shaft 2 or its periphery so as to be tensioned.

[0035] The catheter 1 has the coil 50, which ensures the rigidity of the proximal end side of the curved distal portion 1D of the catheter, and L In this case, the distal catheter section 1D can be bent from the distal end of the coil 50. In order to ensure a certain level of rigidity on the proximal end side of the bending of the catheter distal section 1D, it is preferable that the coil 50 is an uncompressed, so-called tightly wound coil. If the coil 50 is uncompressed, the catheter distal section 1D can be easily bent starting from the distal end of the coil 50. As shown in Figures 7 and 8, an uncompressed coil is, strictly speaking, a coil whose total length L is the length of the coil in its natural state when no external force is applied to the coil and whose total length L is the length of the coil when it is fully compressed. c Relative to L c / L is 1, but L c A coil with a value of / L of 0.95 or more, or 0.9 or more, is also included in the category of a substantially uncompressed coil. If the coil 50 is such an uncompressed coil, the rigidity of the proximal end side of the catheter distal section 1D when bending can be easily ensured, and the catheter distal section 1D can be bent from the distal end of the coil 50 to the distal side. The coil 50 may extend to the proximal end of the shaft 2, or may extend beyond the proximal end of the shaft 2, or the proximal end of the coil 50 may be disposed midway along the shaft 2. The coil 50 has a longitudinal axis d L In this case, the shaft 2 may be switched to a different tube midway.

[0036] The coil 50 is preferably flexible, and can be made of metal or resin, and can be made of metal wire such as stainless steel or nickel-titanium alloy, or synthetic resin wire such as aromatic polyether ketone resin (e.g., PEEK) or polycarbonate resin. The cross-sectional shape of the coil wire 55 forming the coil 50 can be circular, rectangular, or a combination thereof. In particular, the coil 50 is preferably a coil formed by winding a metal wire, and the coil 50 is preferably a coil formed by winding a stainless steel coil wire 55 having a circular cross section. The diameter of the coil wire 55 forming the coil 50 is preferably 0.1 mm to 0.5 mm. When the coil 50 is formed by using a coil wire 55 having a rectangular cross section, each side of the rectangle can be 0.05 mm to 1 mm. The catheter 1 according to the embodiment of the present invention has a longitudinal axis d L Since the internal structure changes at the distal end of the coil 50, it is preferable to select the material, size, and flexibility of the coil 50 so that the stiffness of the catheter 1 does not differ too greatly between the distal and proximal sides of the distal end of the coil 50.

[0037] 2, the catheter 1 has a tubular portion 60 disposed outside the coil 50 in the lumen of the shaft 2. The tubular portion 60 may be a tube made of resin. Alternatively, the tubular portion 60 may be an adhesive layer applied to the outer surface of the coil 50, or a coating made of a resin material or the like formed on the outer surface of the coil 50.

[0038] For the resin that constitutes the tube or coating, the description of the synthetic resin among the materials that constitute the shaft 2 can be referred to, but among them, elastomers made of polyolefin resin, polyimide resin, and polyamide resin are preferred. Examples of adhesives include polyamide adhesives, polyimide adhesives, polyester adhesives, polyurethane adhesives, polyolefin adhesives, and silicone adhesives, but are not particularly limited to these.

[0039] As shown in Figure 2, the longitudinal axis direction d LIn this case, the distal end of the tubular portion 60 is located at the same position as the distal end of the coil 50 or more proximal to the distal end of the coil 50, and the length d from the distal end of the coil 50 to the distal end of the tubular portion 60 is equal to or less than 30 turns of the coil 50. That is, the catheter 1 according to the embodiment of the present invention has a longitudinal axis d L 3, a tubular portion 60 is disposed on the outside of the coil 50 proximal to the distal end of the coil 50, but in a section of length d at the distal end of the coil 50 and distal to the distal end of the coil 50, the tubular portion 60 is not present around the wire 30 and the leaf spring 40 as shown in FIGS. 4 to 6. This configuration prevents interference of the tubular portion 60 with the wire 30, which is a pulling member, and the leaf spring 40, which is a bending member. As a result, force from the proximal side is easily transmitted to the wire 30 disposed in the catheter distal section 1D, and bending of the leaf spring 40 caused by pulling the wire 30 is less affected by the tubular portion 60, making it easier to achieve a desired curved shape for the catheter distal section 1D.

[0040] As shown in FIGS. 2 and 3, the longitudinal axis direction d L In the section proximal to the section of the coil 50 having a length d of 30 turns or less, the tubular portion 60 is disposed outside the coil 50. As a result, in the section where the tubular portion 60 is disposed outside, even if the coil 50 is compressed as the wire 30 is pulled when bending the catheter distal portion 1D, the coil 50 is prevented from moving in the radial direction d. R This prevents deformation such as swelling, and suppresses twisting of the curve of the catheter distal section 1D caused by rotation of the leaf spring 40 connected to the coil 50. Since the tendency of the coil 50 to swell depends on the number of turns of the coil 50, the longitudinal axis direction d from the distal end of the coil 50 to the distal end of the tubular section 60 is L The above effect can be achieved by making the length d equal to or less than a predetermined number of turns of the coil 50.

[0041] Here, one turn of the coil 50 refers to the length of one turn of the coil wire 55 forming the coil 50 in the longitudinal direction of the coil 50 in a natural state where no external force is applied to the coil 50, as shown in Fig. 7. When the coil 50 is an uncompressed coil, the total length L of the coil in the natural state and the total length L of the coil when it is maximally compressed are c Relative to L c When / L is 1, one turn of the coil 50 corresponds to the wire diameter of the coil wire 55 that forms the coil 50. When the coil 50 is not a completely uncompressed coil, as shown in FIG. 7, one turn of the coil 50 can be determined as the length S from one end of one turn of the coil wire 55 to one end of the next turn in the longitudinal axis direction of the coil 50. When the coil 50 is not an uncompressed coil, the length S is the sum of the wire diameter of the coil wire 55 and the length of the gap between the coil wires 55, and is the same as the pitch of the coil 50. The length of 30 turns of the coil 50 is 30 times the length S.

[0042] The length d from the distal end of the coil 50 to the distal end of the tubular portion 60 is preferably 25 turns or less of the coil 50, more preferably 20 turns or less, and may be 15 turns or less, 12 turns or less, or 10 turns or less. L In this case, the distal end of the tubular portion 60 may be disposed at the same position as the distal end of the coil 50, and therefore the length d from the distal end of the coil 50 to the distal end of the tubular portion 60 may be 0 turns of the coil 50, but the length d is preferably 1 turn or more of the coil 50, more preferably 3 turns or more, and even more preferably 5 turns or more. By setting the upper limit of the length d within the above range, the tubular portion 60 can be disposed up to the vicinity of the distal end of the coil 50, which is the base end of the curvature when the catheter distal portion 1D is bent, and the distal end of the coil 50, which is the base end of the curvature, is positioned in the radial direction d R When the lower limit of the length d is within the above range other than 0, the catheter 1 according to the embodiment of the present invention can prevent twisting of the leaf spring 40 due to the rotation of the first connection portion 41 between the coil 50 and the leaf spring 40. L4 and 5, the tubular portion 60 is not disposed on the outside of the distal end of the coil 50, which makes it difficult for a further difference in rigidity due to the tubular portion 60 to occur at the distal end of the coil 50. This makes it possible to prevent twisting and kinking when the catheter distal portion 1D is bent.

[0043] The inner wall of the cylindrical portion 60 may be in full or partial contact with the outer surface of the coil 50, or may not be in contact at all. Even if the inner wall of the cylindrical portion 60 is not in contact with the outer surface of the coil 50, the above-mentioned effect can be achieved by disposing the cylindrical portion 60 outside the coil 50. As shown in Figures 12 to 14, when the inner wall of the cylindrical portion 60 is not in contact with the outer surface of the coil 50, a gap may be formed between the inner wall of the cylindrical portion 60 and the outer surface of the coil 50.

[0044] As shown in FIG. 3, the cylindrical portion 60 has a length d L That is, the cylindrical portion 60 is preferably cylindrical in the radial direction d. R It is preferable that the cross section has a continuous cross section in the radial direction d of the coil 50. As a result, even if the inner wall of the cylindrical portion 60 does not abut on the outer surface of the coil 50, R Alternatively, although not shown, the cylindrical portion 60 can be easily prevented from expanding in the longitudinal direction d L In other words, the cylindrical portion 60 may have a non-cylindrical portion due to a gap or a missing portion in a certain region of the radial direction d. RThe cylindrical portion 60 may have a discontinuous cross section in the cross section. The position where the tubular portion 60 has the cut or missing portion is not particularly limited, but for example, the cylindrical portion 60 may be cylindrical on the proximal side and have a cylindrical shape with a cut or missing portion at the distal end. Also, for example, the cylindrical portion 60 may be cylindrical on the distal side and have a cylindrical shape with a cut or missing portion somewhere on the proximal side. Even if the cylindrical portion 60 has a non-cylindrical portion in this way, for example, the inner wall of the cylindrical portion 60 may be in full or partial contact with the outer surface of the coil 50, thereby preventing the radial direction d of the coil 50 from being broken. R Alternatively, even if the cylindrical portion 60 has a non-cylindrical portion and the inner wall of the cylindrical portion 60 does not abut against the outer surface of the coil 50, by providing a second fixing portion 61 as shown in FIGS. R This can prevent swelling.

[0045] Longitudinal direction d L In the embodiment, the cylindrical portion 60 may extend to the proximal end of the coil 50, or the proximal end of the cylindrical portion 60 may be located distal to the proximal end of the coil 50. The cylindrical portion 60 may be formed of a single member from the distal end to the proximal end, or may be formed of a single member extending in the longitudinal axis direction d L The longitudinal axis direction d may be switched to another member at any position. L In this case, the cylindrical portion 60 is preferably arranged outside the coil 50 in a section that is 50% or more of the length of the coil 50. The section in which the cylindrical portion 60 is arranged outside the coil 50 is more preferably 60% or more of the length of the coil 50, even more preferably 75% or more, and may be 80% or more, 90% or more, or even 100%. By arranging the cylindrical portion 60 outside the coil 50 in the above range, the cylindrical portion 60 can prevent the coil 50 from being twisted in the radial direction d R This makes it easier to prevent the bulge from occurring.

[0046] 2 and 3, it is preferable that at least a part of the inner wall of the cylindrical portion 60 abuts against the outer surface of the coil 50. More preferably, the entire inner wall of the cylindrical portion 60 abuts against the outer surface of the coil 50. This allows the radial direction d of the coil 50 to be R This makes it easier to suppress swelling.

[0047] When the cylindrical portion 60 is a tube or a film, the cylindrical portion 60 can be provided so that the inner wall of the cylindrical portion 60 abuts against the outer surface of the coil 50 by, for example, placing the coil 50 in the lumen of a resin molded into a cylindrical shape and heat-shrinking the resin to the outside of the coil 50. If the cylindrical portion 60 is formed on the outside of the coil 50 in this way, the cylindrical portion 60 is in close contact with the outer surface of the coil 50, and the radial direction d of the coil 50 is R However, even when the cylindrical portion 60 is formed so as to be in close contact with the outer surface of the coil 50, the cylindrical portion 60 is not fixed to the outer surface of the coil 50, and the cylindrical portion 60 and the coil 50 are spaced apart from each other in the longitudinal axis direction d. L This prevents the coil 50 from being constrained by the cylindrical portion 60 more than necessary, thereby improving the flexibility of the catheter 1.

[0048] Longitudinal direction d L In this configuration, the distal end of the tubular portion 60 is preferably located proximal to the distal end of the coil 50. In other words, the length d is preferably not zero. This allows the tubular portion 60 to be configured not to be disposed at the distal end of the coil 50, making it easier to prevent interference of the tubular portion 60 with the wire 30 and the leaf spring 40. As a result, force from the proximal side is transmitted to the wire 30 of the catheter distal portion 1D without interference, and bending of the leaf spring 40 due to pulling of the wire 30 is not impeded, making it easier to achieve the desired curved shape of the catheter distal portion 1D. Furthermore, since it is possible to make it less likely that an additional rigidity step will be created by the tubular portion 60 at the distal end of the coil 50, kinking at the distal end of the coil 50 can be prevented when the catheter distal portion 1D is bent.

[0049] As shown in FIGS. 2 to 6 and 9 to 14, the longitudinal axis direction d L In the figure, the wire 30 and the leaf spring 40 may be exposed to the lumen of the shaft 2 at a position distal to the distal end of the coil 50. Alternatively, although not shown, L In the embodiment, the wire 30 and the leaf spring 40 may be disposed in a lumen provided in the shaft 2 or in the cavity of another tubular member distal to the distal end of the coil 50. In either case, since the distal end of the tubular portion 60 is located proximal to the distal end of the coil 50, the tubular portion 60, which prevents the coil 50 from expanding, can be prevented from interfering with the wire 30 and the leaf spring 40.

[0050] Longitudinal direction d L In the above, it is preferable that the first connection portion 41 is not disposed inside the cylindrical portion 60. That is, it is preferable that the first connection portion 41 is disposed in a section having a length d from the distal end of the coil 50 to the distal end of the cylindrical portion 60. The first connection portion 41 is likely to have high rigidity because it is the portion where the leaf spring 40 is connected to the coil 50, as shown in an example in FIG. 5 , but since the cylindrical portion 60 is not disposed in this portion, it is possible to prevent a further difference in rigidity caused by the cylindrical portion 60.

[0051] As shown in Figure 9, the longitudinal axis direction d L In the catheter distal section 1D, the proximal end of the tubular section 60 is preferably located distal to the proximal end of the coil 50, and the coil 50 preferably has a first fixed portion 51 fixed to the shaft 2 proximal to the proximal end of the tubular section 60. By having the first fixed portion 51 fixed to the shaft 2, it becomes easier to suppress twisting of the coil 50, and the catheter distal section 1D can be curved in a certain direction without twisting. It is preferable that the first fixed portion 51 is formed by some kind of fixing means, such as bonding with an adhesive or brazing with solder, rather than simply bonding the coil 50 to the shaft 2.

[0052] Longitudinal direction d LIn the coil 50, the length L1 from the distal end of the first fixed portion 51 to the proximal end of the tubular portion 60 is preferably 20 turns or less of the coil 50. The length L1 is more preferably 15 turns or less of the coil 50, even more preferably 12 turns or less, and may be 10 turns or less. Furthermore, since the first fixed portion 51 may be provided so as to be in contact with the proximal end of the tubular portion 60, an embodiment in which the length L1 is 0 and the distal end of the first fixed portion 51 and the proximal end of the tubular portion 60 are not separated is also acceptable. Alternatively, the distal end of the first fixed portion 51 and the proximal end of the tubular portion 60 may be separated from each other, in which case the length L1 is preferably 3 turns or more of the coil 50, and more preferably 5 turns or more. By setting the upper limit of the length L1 within the above range, the first fixing portion 51 can be provided near the proximal end of the tubular portion 60, which makes it easier to prevent twisting of the coil 50 and allows the catheter distal portion 1D to be curved in a certain direction without twisting. By setting the lower limit of the length L1 within the above range, the first fixing portion 51 can be provided near the proximal end of the tubular portion 60 in the longitudinal axis direction d L Since the tubular portion 60 can be positioned at a certain distance proximal to the first fixing portion 51, the change in rigidity caused by the tubular portion 60 and the change in rigidity caused by the first fixing portion 51 can be prevented from overlapping, and the flexibility of the catheter distal portion 1D can be improved, making it easier to achieve the desired curved shape.

[0053] Alternatively, although not shown, the first fixing portion 51 may be L The first fixing portion 51 may be provided so as to extend distally beyond the proximal end of the cylindrical portion 60, and a part of the first fixing portion 51 may fix the cylindrical portion 60 and the shaft 2 together.

[0054] The longitudinal axis direction d of the first fixing portion 51 L The length of the first fixing portion 51 in the longitudinal direction d is preferably 50 turns or less of the coil 50, more preferably 30 turns or less, and even more preferably 10 turns or less. L If the length of the first fixing part 51 is long, the rigidity of the catheter distal part 1D at the part where the first fixing part 51 is provided will be high, and there is a risk of problems such as kinking of the catheter distal part 1D due to the difference in rigidity. LIf the length of the first fixing part 51 is within the above range, the difference in rigidity caused by the first fixing part 51 can be reduced. Furthermore, if the catheter 1 has a conductor connected to an electrode or the like disposed at the tip, the conductor is disposed inside the shaft 2 and outside the coil 50. Therefore, the length of the first fixing part 51 in the longitudinal axis direction d L By setting the length of the first fixing portion 51 within the above range, the influence of the first fixing portion 51 on the lead wire can be suppressed, and the lead wire can be prevented from being pulled, making it possible to easily bend the catheter distal portion 1D into a desired shape. L The lower limit of the length of the longitudinal axis d is not particularly limited, but is preferably at least three turns of the coil 50, more preferably at least five turns, and even more preferably at least seven turns. L In this configuration, it is preferable that the length of the tubular portion 60, the length of the first fixing portion 51, and the length L1 from the distal end of the first fixing portion 51 to the proximal end of the tubular portion 60 decrease in this order. With this configuration, the tubular portion 60 and the first fixing portion 51 can prevent deformation such as swelling and twisting of the coil 50, while reducing the effect of differences in rigidity due to the various components, making it easier to shape the catheter distal portion 1D into the desired curved shape.

[0055] The first fixing portion 51 may be provided over the entire 360° circumferential direction of the space outside the coil 50 and inside the shaft 2, as shown in FIG. 10 , or may be provided over a portion of the 360° circumferential direction of the space, as shown in FIG. 11 . When the first fixing portion 51 is provided over a portion of the 360° circumferential direction of the space, there may be one or more first fixing portions 51. In this case, the total angle over which the first fixing portions 51 are provided in the circumferential direction is preferably 60° or more, and more preferably 90° or more. If the first fixing portions 51 are provided within the above range, the fixing strength between the coil 50 and the shaft 2 can be ensured. Furthermore, the total angle over which the first fixing portions 51 are provided in the circumferential direction is preferably 240° or less, and more preferably 180° or less. If the first fixing portions 51 are provided within the above range, the rigidity difference caused by the first fixing portions 51 can be suppressed. Furthermore, if the catheter 1 has a conductor connected to an electrode or the like disposed at the tip, the conductor can be inserted into a space outside the coil 50 and inside the shaft 2 where the first fixing part 51 is not disposed. This allows the conductor to be configured not to be fixed by the first fixing part 51, preventing the conductor from being pulled and making it easier to bend the catheter distal part 1D into a desired shape.

[0056] In one embodiment of the present invention in which the proximal end of the tubular portion 60 is located distal to the proximal end of the coil 50 as described above, L The length of the cylindrical portion 60 in the radial direction d of the coil 50 is preferably equal to or greater than 1 / 4 of the length of the leaf spring 40. R In addition, the effect of preventing deformation such as bulging of the first fixing portion 51 in the longitudinal axis direction d L Since the position of the first connecting portion 41 can be sufficiently separated from the first connecting portion 41, the stiffness change caused by the first connecting portion 41 and the stiffness change caused by the first fixing portion 51 can be prevented from overlapping, making it easier to improve the flexibility of the catheter distal portion 1D and to achieve the desired curved shape.

[0057] As shown in FIG. 12, a catheter 1 according to another embodiment of the present invention preferably has a second fixing portion 61 at which the tubular portion 60 is fixed to the shaft 2. By having the second fixing portion 61 at which the tubular portion 60 is fixed to the shaft 2, twisting of the coil 50 can be prevented, and the catheter distal portion 1D can be easily bent in a certain direction without twisting. The second fixing portion 61 is preferably formed by some fixing means, such as bonding with an adhesive or brazing with solder, rather than simply adhering the tubular portion 60 to the shaft 2. By fixing the tubular portion 60 to the shaft 2, rather than the coil 50 having a certain level of rigidity, twisting of the catheter distal portion 1D can be prevented while improving the flexibility of the catheter distal portion 1D. In addition, the tubular portion 60 and the coil 50 are fixed to the shaft 2 in the longitudinal axis direction d. L In the embodiment where the coil 50 and the cylindrical portion 60 are slidable relative to each other, a certain degree of freedom is ensured for the coil 50 even when the cylindrical portion 60 is fixed to the shaft 2, so the flexibility of the catheter distal portion 1D is unlikely to be impaired.

[0058] In the above embodiment, the cylindrical portion 60 has a length in the longitudinal axis direction d L Alternatively, the proximal end of the tubular portion 60 may extend to the proximal end of the coil 50 in the longitudinal axis direction d L The catheter 1 may further have a first fixing portion 51 located distal to the proximal end of the coil 50, and the coil 50 is fixed to the shaft 2 proximal to the proximal end of the tubular portion 60. In other words, the catheter 1 may have both the first fixing portion 51 and the second fixing portion 61.

[0059] The longitudinal axis direction d of the second fixing portion 61 L The length of the second fixing portion 61 in the longitudinal direction d is preferably equal to or less than 50 turns of the coil 50, more preferably equal to or less than 30 turns, and even more preferably equal to or less than 10 turns. L If the length of the second fixing part 61 is long, the rigidity of the catheter distal part 1D at the part where the second fixing part 61 is provided increases, and there is a risk of a problem such as kinking of the catheter distal part 1D due to the difference in rigidity. LIf the length of the second fixing portion 61 is within the above range, the difference in rigidity caused by the second fixing portion 61 can be reduced. Furthermore, if the catheter 1 has a conductor connected to an electrode or the like disposed at the tip, the conductor is disposed inside the shaft 2 and outside the coil 50 and the cylindrical portion 60. Therefore, the length of the second fixing portion 61 in the longitudinal axis direction d L By setting the length of the second fixing portion 61 within the above range, the influence of the second fixing portion on the lead wire can be suppressed, and the lead wire can be prevented from being pulled, making it possible to easily bend the catheter distal portion 1D into a desired shape. L The lower limit of the length is not particularly limited, but is preferably at least three turns of the coil 50, more preferably at least five turns, and even more preferably at least seven turns.

[0060] The second fixing portion 61 may be provided over the entire 360° circumferential range of the space outside the cylindrical portion 60 and inside the shaft 2, as shown in FIG. 13 , or may be provided over a portion of the 360° circumferential range of the space, as shown in FIG. 14 . When the second fixing portion 61 is provided over a portion of the 360° circumferential range of the space, there may be one or more second fixing portions 61. In this case, the total angle over which the second fixing portions 61 are provided in the circumferential direction is preferably 60° or more, more preferably 90° or more. If the second fixing portions 61 are provided within the above range, the fixing strength between the cylindrical portion 60 and the shaft 2 can be ensured. Furthermore, the total angle over which the second fixing portions 61 are provided in the circumferential direction is preferably 240° or less, more preferably 180° or less. If the second fixing portions 61 are provided within the above range, the rigidity difference caused by the second fixing portions 61 can be suppressed. Furthermore, if the catheter 1 has a conductor connected to an electrode or the like disposed at the tip, the conductor can be inserted into the space outside the tubular portion 60 and inside the shaft 2 where the second fixing portion 61 is not disposed. This allows the conductor to be configured not to be fixed by the second fixing portion 61, preventing the conductor from being pulled and making it possible to easily bend the catheter distal portion 1D into a desired shape.

[0061] Longitudinal direction d LIn the above, the length L2 from the distal end of the second fixing portion 61 to the distal end of the coil 50 is preferably two times or less the length of the leaf spring 40. The length L2 is more preferably 1.5 times or less the length of the leaf spring 40, and even more preferably 1 time or less. The length L2 is preferably 1 / 3 or more the length of the leaf spring 40, more preferably 1 / 2 or more, and even more preferably 3 / 4 or more. When the length L2 is within the above range, the longitudinal axis direction d L Since the tubular portion 60 and the shaft 2 can be fixed at a position within a predetermined distance proximal to the distal end of the coil 50, which is the base end of the bending when bending the catheter distal portion 1D, twisting of the coil 50 can be more easily prevented, and the catheter distal portion 1D can be bent in a fixed direction without twisting.

[0062] Longitudinal direction d L In the above, the distal end of the second fixing portion 61 is located proximal to the proximal end of the first connecting portion 41, and the length L3 from the distal end of the second fixing portion 61 to the proximal end of the first connecting portion 41 is preferably 1 / 4 or more of the length of the leaf spring 40. The length L3 is more preferably 1 / 3 or more of the length of the leaf spring 40, and even more preferably 1 / 2 or more. The upper limit of the length L3 can be set to the same as the preferred range of the length L2. If the length L3 is within the above range, the longitudinal axis direction d of the second fixing portion 61 is L Since the position of the second fixing portion 61 can be sufficiently separated from the first connecting portion 41, the stiffness change caused by the first connecting portion 41 and the stiffness change caused by the second fixing portion 61 can be prevented from overlapping, making it easier to improve the flexibility of the catheter distal portion 1D and to achieve the desired curved shape.

[0063] The catheter 1 according to the embodiment of the present invention may have another fixing portion where the coil 50 or the tubular portion 60 is fixed to the shaft 2 on the proximal side of the proximal end of the second fixing portion 61. If the fixing portion is on the proximal side of the proximal end of the second fixing portion 61, it is sufficiently far from the distal end of the coil 50 and the first connecting portion 41, and therefore has little effect on the change in the rigidity of the catheter 1. However, from the viewpoint of reducing the number of manufacturing steps and ensuring the slidability of the conductor wire when the catheter 1 has one, it is preferable to keep the number of fixing portions to a minimum. LThe number of other fixing portions in is preferably 5 or less, more preferably 3 or less, and may be 2 or less, 1 or less, or 0.

[0064] The catheter 1 according to the embodiment of the present invention has a longitudinal axis d L In this case, it is preferable that the tubular portion 60 and the shaft 2 are not fixed to each other distally of the distal end of the second fixing portion 61. This prevents a portion near the distal end of the coil 50 from having increased rigidity due to the fixing portion, thereby preventing a step in rigidity in the catheter distal portion 1D. [Explanation of symbols]

[0065] 1: Catheter 1D: Distal part of the catheter 2: Shaft 7: Handle 20:Tip 30: Wire 40: Leaf spring 40a: One side 40b: Other side 41: First connection part 42: Second connection part 50: Coil 51: 1st fixed part 55: Coil wire 60: Cylindrical part 61:Second fixed part d: Length from the distal end of the coil to the distal end of the tubular part d L : Longitudinal axis direction d R :radial direction L: length of the coil in its natural state L C : Coil length at maximum compression L1: Length from the distal end of the first fixing part to the proximal end of the tubular part L2: Length from the distal end of the second fixation part to the distal end of the coil L3: Length from the distal end of the second fixing part to the proximal end of the first connecting part

Claims

1. The catheter has a distal end and a proximal end in a longitudinal direction and has a lumen extending in the longitudinal direction. A shaft and a lumen extending in the longitudinal direction and disposed in the lumen of the shaft; A coil and a cylindrical portion disposed outside the coil in the inner cavity of the shaft; The coil is inserted into the inner cavity of the shaft, or the coil is inserted into the outer cavity of the cylindrical portion. a wire located distal to the distal end of the coil and on the distal side of the wire; one or more wires connected directly or indirectly to the distal end of the shaft; a leaf spring extending through the lumen of the shaft, the proximal end of the leaf spring being in contact with the coil; a leaf spring having a first connection portion directly or indirectly connected to a distal end of the shaft, and a second connection portion at which the distal end of the leaf spring is fixed directly or indirectly to a distal end of the shaft; In the longitudinal axis direction, the distal end of the cylindrical portion is the same as or closer to the distal end of the coil. the length from the distal end of the coil to the distal end of the tubular portion is equal to or less than 30 turns of the coil; A catheter in which the entire inner wall of the cylindrical portion is in full contact with the outer surface of the coil.

2. In the longitudinal axis direction, the distal end of the tubular portion is located proximal to the distal end of the coil. The catheter of claim 1.

3. a first connecting portion that is not disposed inside the cylindrical portion in the longitudinal axis direction; 3. The catheter according to claim 1 or 2.

4. In the longitudinal axis direction, the proximal end of the tubular portion is located distal to the proximal end of the coil. The coil is fixed to the shaft on the proximal side of the proximal end of the cylindrical portion. The catheter according to any one of claims 1 to 3, further comprising a first fixing portion.

5. a length from a distal end of the first fixing portion to a proximal end of the tubular portion in the longitudinal axis direction; 5. The catheter of claim 4, wherein the number of turns of the coil is 20 or less.

6. The catheter according to any one of claims 1 to 5, wherein the tubular portion has a second fixing portion fixed to the shaft.

7. a length from a distal end of the second fixed portion to a distal end of the coil in the longitudinal axis direction; The catheter according to claim 6, wherein the length of the leaf spring is not more than twice the length of the leaf spring.

8. 8. The catheter according to claim 6 or 7, wherein, in the longitudinal axis direction, the distal end of the second fixing portion is located proximal to the proximal end of the first connecting portion, and the length from the distal end of the second fixing portion to the proximal end of the first connecting portion is 1 / 4 or more of the length of the leaf spring.

9. The device further includes an electrode provided on the shaft and a conductor connected to the electrode, The catheter according to any one of claims 1 to 8, wherein the conducting wire is arranged inside the shaft and outside the tubular portion, proximal to the first connecting portion.

10. A catheter described in any one of claims 1 to 9, wherein the wire and the leaf spring are exposed in the inner cavity of the shaft distal to the distal end of the coil.

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