Catheter

Abstract

To provide a catheter capable of easily preventing deformation of a distal end part of the catheter.SOLUTION: A catheter includes: an outer tube 20 having a lumen 20a extending in a longitudinal axis direction x; an inner tube 30 extending in the lumen 20a of the outer tube 20; a spacer member 40 arranged outside in a radial direction of the inner tube 30; a tip tube 50 arranged more on a distal side than a distal end of the outer tube 20, and outside in a radial direction of the spacer member 40; and a cover tube 60 arranged outside in the radial direction of the tip tube 50 and the outer tube 20.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In the examination and treatment of visceral diseases, the use of a catheter enables a minimally invasive method that does not involve open abdominal surgery. For example, in the examination and treatment of arrhythmia such as atrial fibrillation, the tip side of the catheter is delivered into the heart, and a tip tip is sometimes provided at the distal end of the catheter so as not to damage blood vessels or the inner wall of the heart. Patent Document 1 discloses that a catheter shaft with a double tube structure is constructed by connecting a tip tip to the tip side of a catheter shaft, inserting the tip of an inner tube into a through hole formed in the tip tip, and inserting the inner tube connected to the tip tip into the inside of an outer tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 145503 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned conventional catheters have a problem in that the connection strength of the tip provided at the distal end of the catheter needs to be improved, and that the space between the outer tube and the inner tube is reduced in diameter and deformed by heating when connecting the tip to the distal end of the catheter. In view of the above circumstances, the object of the present invention is to provide a catheter that can improve the connection strength of the members connected to the distal end of the catheter and can easily prevent deformation of the distal end of the catheter. [Means for solving the problem]

[0005] A catheter according to an embodiment of the present invention that can solve the above problems is as follows. [1] A catheter having a longitudinal direction and a radial direction perpendicular to the longitudinal direction, and having a distal end and a proximal end in the longitudinal direction, the catheter comprising: an outer tube having an inner lumen extending in the longitudinal direction; an inner tube extending into the inner lumen of the outer tube; a spacer member disposed on the outside of the inner tube in the radial direction; a tip tube disposed distal to the distal end of the outer tube and on the outside of the spacer member in the radial direction; and a cover tube disposed on the outside of the tip tube and the outer tube in the radial direction.

[0006] Since the tip tube is disposed distal to the distal end of the outer tube, the tip tube can function as a tip tip, and since the cover tube is disposed radially outward of the tip tube and the outer tube, the connection strength between the tip tube and the outer tube can be improved. Also, since the tip tube is disposed radially outward of the spacer member, i.e., the spacer member is disposed radially inward of the tip tube and radially outward of the inner tube, the space between the outer tube and the inner tube can be prevented from shrinking in diameter and becoming deformed. This improves the strength of the distal end of the catheter, and also ensures a space between the outer tube and the inner tube, making it possible to insert a separate member such as a lead wire into the space, and the catheter can be used for various examinations and treatments.

[0007] The catheter according to the embodiment of the present invention is preferably any one of the following items [2] to

[10] . [2] The catheter described in [1], wherein the spacer member is made of a material having a higher Shore D hardness than the material constituting the tip tube. [3] A catheter according to [1] or [2], wherein the spacer member is tubular. [4] The catheter according to any one of [1] to [3], wherein in the longitudinal axis direction, the proximal end of the spacer member is located proximal to the proximal end of the tip tube. [5] The catheter according to any one of [1] to [4], wherein the distal end of the inner tube is located distal to the proximal end of the tip tube in the longitudinal axis direction. [6] The catheter according to any one of [1] to [5], wherein in the longitudinal axis direction, the proximal end of the cover tube is located distal to the proximal end of the spacer member. [7] The catheter according to any one of [1] to [6], wherein the tip tube is made of a material having a lower Shore D hardness than the material constituting the cover tube. [8] A catheter described in any of [1] to [7], wherein the outer surface of the inner tube is welded to the inner surface of the spacer member in the radial direction, the outer surface of the spacer member in the radial direction is welded to the inner surface of the tip tube, and the outer surface of the tip tube is welded to the inner surface of the cover tube. [9] The catheter described in any of [1] to [8] is an electrode catheter having a plurality of electrodes spaced apart in the longitudinal axis direction on the outer surface of the distal portion of the outer tube.

[10] A catheter as described in [9], wherein, in the longitudinal axis direction, the proximal end of the spacer member is positioned at the same position as the distal end of a first electrode that is positioned most distally among the plurality of electrodes or distal to the distal end of the first electrode. Effect of the Invention

[0008] According to the above-mentioned catheter, the connection strength of the member connected to the distal end of the catheter can be improved, and deformation of the distal end of the catheter can be easily prevented, thereby preventing the member connected to the distal end of the catheter from falling off and preventing the distal end of the catheter from breaking, enabling safe and efficient treatment. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of a catheter according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of the catheter shown in FIG. 1 when the distal portion is curved. [Diagram 3] 2 is a longitudinal cross-sectional view of the distal portion of the catheter shown in FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view of the distal portion of the catheter shown in FIG. 3 taken along line IV-IV. [Diagram 5] FIG. 5 is a cross-sectional view showing a modified example of FIG. [Figure 6] 6 is a cross-sectional view of the distal portion of the catheter shown in FIG. 3 taken along line VI-VI. [Figure 7] 7 is a cross-sectional view of the distal portion of the catheter shown in FIG. 3 taken along line VII-VII. [Figure 8] FIG. 8 is a cross-sectional view of the distal portion of the catheter shown in FIG. 3 taken along line VIII-VIII. [Figure 9] 2 is a longitudinal cross-sectional view of the distal portion of the catheter shown in FIG. 1. [Figure 10] FIG. 13 is a side view of a catheter according to another embodiment of the present invention. [Figure 11] FIG. 11 is a longitudinal cross-sectional view of the distal portion of the catheter shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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.

[0011] A catheter according to an embodiment of the present invention will be described with reference to Figs. 1 to 11. Fig. 1 is a side view of a catheter according to an embodiment of the present invention. Fig. 2 is a side view of the catheter shown in Fig. 1 when the distal part is curved. Fig. 3 is a longitudinal axial cross-sectional view of the distal part of the catheter shown in Fig. 1. Fig. 4 is a IV-IV cross-sectional view of the distal part of the catheter shown in Fig. 3, and Fig. 5 is a cross-sectional view showing a modified example of Fig. 4. Figs. 6 to 8 are VI-VI, VII-VII, and VIII-VIII cross-sectional views, respectively, of the distal part of the catheter shown in Fig. 3. Fig. 9 is a longitudinal axial cross-sectional view of the distal part of the catheter shown in Fig. 1. Fig. 10 is a side view of a catheter according to another embodiment of the present invention. Fig. 11 is a longitudinal axial cross-sectional view of the distal part of the catheter shown in Fig. 10.

[0012] 1, the catheter 10 has a longitudinal direction x which is the extension direction of the outer tube 20, a radial direction y which is perpendicular to the longitudinal direction x and extends radially from the central axis of the outer tube 20, and a circumferential direction z which is a direction along the outer periphery of the outer tube 20, and has a distal end and a proximal end in the longitudinal direction x. In this specification, the direction toward the user's hand in the longitudinal direction x is referred to as the proximal side, and the side opposite to the proximal side, i.e., the direction toward the subject of treatment, is referred to as the distal side.

[0013] The members and parts of the catheter 10 each have a longitudinal axis direction, a radial direction, and a circumferential direction, which may or may not be the same as the longitudinal axis direction x, radial direction y, and circumferential direction z of the catheter 10. However, for ease of understanding, this specification will be described as assuming that all members and parts have the same longitudinal axis direction, radial direction, and circumferential direction as the longitudinal axis direction x, radial direction y, and circumferential direction z1 of the catheter 10.

[0014] 2, the distal portion of the catheter 10 may be curved in its natural state by forming a bend in the distal portion of the catheter 10 before use. By forming the distal portion of the catheter 10 to be curved, it becomes easier to follow the curvature of blood vessels and the inside of the heart, and it is possible to improve the ease of insertion and the effect of preventing damage to the body cavity wall. Alternatively, the distal portion of the catheter 10 may be curved by pulling a wire fixed to the distal end of the catheter 10 from the proximal side.

[0015] As shown in FIG. 2, when the distal portion of the catheter 10 is curved, the longitudinal axis direction x is curved along the extension direction of the catheter 10, and a radial direction y and a circumferential direction z are defined at each position in the longitudinal axis direction x.

[0016] 1 and 2, a handle 70 may be connected to the proximal side of the outer tube 20. A user can easily operate the catheter 10 by gripping the handle 70. A guidewire tube 71 through which a guidewire is inserted and a guidewire port 72 serving as an insertion port for the guidewire may be provided on the proximal side of the handle 70.

[0017] 3, the catheter 10 has an outer tube 20 having a lumen 20a extending in the longitudinal axis direction x, and an inner tube 30 extending into the lumen 20a of the outer tube 20. By disposing the inner tube 30 in the lumen 20a of the outer tube 20, a double-tube structure can be formed, and various functions can be imparted to the catheter 10 by disposing components such as conducting wires connected to electrodes (described later), an internal structure for bending the distal portion of the catheter 10, and a guide wire in the space inside the outer tube 20 and outside the inner tube 30, or in the lumen 30a of the inner tube 30.

[0018] When using the catheter 10 for examination or treatment, the catheter 10 is inserted into a body cavity from the distal end side of the outer tube 20 and the inner tube 30, and the distal end of the catheter 10 is delivered to the treatment site by operating the handle 70 or the like. For this reason, it is preferable that the outer tube 20 and the inner tube 30 are flexible. The outer tube 20 and the inner tube 30 can be made of a resin or a metal.

[0019] Specific examples of the resin constituting the outer tube 20 and the inner tube 30 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 ketones, such as PEEK; polyether polyamide resins; polyurethane resins; fluorine resins, such as PTFE, PFA, ETFE; vinyl chloride resins; and silicone resins, as well as natural rubber. Specific examples of the metal constituting the outer tube 20 and the inner tube 30 include stainless steel, carbon steel, and nickel-titanium alloys. These may be used alone or in combination of two or more.

[0020] The outer tube 20 and the inner tube 30 are not particularly limited in configuration as long as they have a cylindrical structure, and examples thereof include a hollow coil formed by winding one or more wires in a spiral shape, a hollow coil or a hollow body with at least one of the inner and outer surfaces coated with a resin in the longitudinal axis direction x, a cylindrical resin tube, or a combination of these. The outer tube 20 and the inner tube 30 may each have a single-layer structure or a multi-layer structure. Alternatively, the outer tube 20 and the inner tube 30 may each have a single layer in a portion in the longitudinal axis direction x or the circumferential direction z, and the other portion may have a multi-layer structure. When the outer tube 20 and the inner tube 30 have a multi-layer structure, for example, the outer layer is preferably made of a polyamide resin or a polyether polyamide resin, and the inner layer is preferably made of a fluorine-based resin having high slipperiness. Furthermore, when the outer tube 20 and the inner tube 30 have a multi-layer structure, for example, a metal braid may be provided as an intermediate layer of the resin tube. The outer tube 20 and the inner tube 30 may have the same configuration or different configurations.

[0021] The length in the longitudinal direction x of the outer tube 20 and the inner tube 30 can be selected to be an appropriate length for treatment. For example, the length in the longitudinal direction x of the outer tube 20 and the inner tube 30 can be 400 mm or more and 2000 mm or less. The length in the longitudinal direction x of the outer tube 20 and the inner tube 30 should be relatively long when the tip of the catheter 10 is inserted from a lower limb vein and delivered to the heart, and may be relatively short when the tip of the catheter 10 is inserted from a subclavian vein or a jugular vein and delivered to the heart.

[0022] The outer diameter of the outer tube 20 is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 1 mm or more. By setting the lower limit of the outer diameter of the outer tube 20 within the above range, the outer tube 20 can be given an appropriate rigidity, and the catheter 10 can be made to have high insertability into blood vessels. Moreover, the outer diameter of the outer tube 20 is preferably 3 mm or less, more preferably 2.8 mm or less, and even more preferably 2.5 mm or less. By setting the upper limit of the outer diameter of the outer tube 20 within the above range, the outer diameter of the catheter 10 can be prevented from becoming too large, and low invasiveness can be improved. Furthermore, the outer diameter of the outer tube 20 may be 2.0 mm or less, 1.8 mm or less, 1.7 mm or less, or 1.5 mm or less. This makes it possible to suppress the outer diameter of the distal end of the catheter 10, and to deliver the distal end of the catheter 10 to the periphery of the coronary sinus.

[0023] The thickness of the outer tube 20, i.e., the thickness of the side wall of the outer tube 20, is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. By setting the lower limit of the thickness of the outer tube 20 within the above range, it is possible to increase the rigidity of the outer tube 20 and provide a catheter 10 with good insertability into a blood vessel. Moreover, the thickness of the outer tube 20 is preferably 350 μm or less, more preferably 300 μm or less, and even more preferably 250 μm or less. By setting the upper limit of the thickness of the outer tube 20 within the above range, it is possible to widen the lumen 20a of the outer tube 20, making it easier to arrange the inner tube 30, and to make the electrodes multipolar when the catheter 10 is an electrode catheter described later.

[0024] The outer diameter of the inner tube 30 is not particularly limited as long as the inner tube 30 can be placed in the lumen 20a of the outer tube 20, but is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. By setting the lower limit of the inner tube 30 within the above range, the inner tube 30 can be given appropriate rigidity, and the catheter 10 can be made to have high insertability into blood vessels. Furthermore, the outer diameter of the inner tube 30 is preferably 2.8 mm or less, more preferably 2.5 mm or less, and even more preferably 2.0 mm or less. By setting the upper limit of the outer diameter of the inner tube 30 within the above range, the inner tube 30 can be easily placed in the lumen 20a of the outer tube 20. Furthermore, the outer diameter of the inner tube 30 may be 1.8 mm or less, 1.7 mm or less, 1.5 mm or less, 1.2 mm or less, or 1.0 mm or less when the outer diameter of the outer tube 20 is small.

[0025] The thickness of the inner tube 30 , i.e., the thickness of the side wall of the inner tube 30 , may be equal to the thickness of the outer tube 20 or may be thinner than the thickness of the outer tube 20 .

[0026] 3 to 5, the catheter 10 has a spacer member 40 disposed on the outside of the inner tube 30 in the radial direction y, and a tip tube 50 disposed distal to the distal end of the outer tube 20 and disposed outside in the radial direction y of the spacer member 40. That is, the tip tube 50 is disposed outside the inner tube 30 in the radial direction y via the spacer member 40 and distal to the distal end of the outer tube 20.

[0027] In this way, by arranging the tip tube 50 via the spacer member 40 on the outside of the inner tube 30 in the radial direction y, the distal end portions of the outer tube 20 and the inner tube 30 can have a stable double tube structure. Furthermore, by arranging the tip tube 50, which is a member different from the outer tube 20, on the distal side of the distal end of the outer tube 20, it is possible to impart functions such as making the distal end of the catheter 10 less likely to damage the body cavity wall and easier to insert into the body cavity by controlling the properties of the tip tube 50, such as hardness and flexibility.

[0028] In addition, as shown in Figs. 3 to 5, the spacer member 40 is disposed between the tip tube 50 and the inner tube 30 in the radial direction y, so that the interval between the inner wall of the tip tube 50 and the outer wall of the inner tube 30 can be prevented from being reduced. This makes it possible to prevent the distal end of the catheter 10 from being deformed and broken. In addition, the spacer member 40 is disposed between the tip tube 50 and the inner tube 30 in the radial direction y, so that it is easy to prevent the deformation of the distal end of the catheter 10 due to the collapse of the lumen 20a of the outer tube 20 disposed proximal to the proximal end of the tip tube 50, that is, the collapse of the space inside the outer tube 20 and outside the inner tube 30 in the radial direction y. This makes it possible to secure the lumen 20a of the outer tube 20, that is, the space inside the outer tube 20 and outside the inner tube 30, without collapsing, as shown in Fig. 6, and makes it possible to insert a member such as a lead wire into the space while preventing the distal end of the catheter 10 from being broken.

[0029] Specifically, if the distal end of the catheter 10 is subjected to processing such as heating when the tip tube 50 is disposed distal to the distal end of the outer tube 20, the distal end of the catheter 10 may shrink in diameter due to heat, and the gap between the inner wall of the tip tube 50 and the outer wall of the inner tube 30 may shrink, which may result in the collapse of the lumen 20a of the outer tube 20. That is, the space inside the outer tube 20 and outside the inner tube 30 in the radial direction y may collapse and deform, but the arrangement of the spacer member 40 can prevent such deformation.

[0030] In particular, in the case of a catheter 10 in which the outer tube 20 has a small outer diameter, such as 2.5 mm or less, 2.0 mm or less, 1.8 mm or less, 1.7 mm or less, or 1.5 mm or less, when heat is applied to the distal end of the catheter 10, the outer diameter suddenly reduces, which becomes the starting point for bending, and the distal end of the catheter 10 is likely to become deformed and break. However, since the catheter 10 has the spacer member 40, the spacer member 40 can suppress the sudden reduction in diameter and prevent the starting point for bending from occurring, thereby preventing bending of the distal end of the catheter 10.

[0031] As shown in Fig. 3, the spacer member 40 is preferably disposed at the distal end of the catheter 10, and as shown in Fig. 6, it is preferable that no member functioning as a spacer is disposed in the space inside the outer tube 20 and outside the inner tube 30 proximal to the proximal end of the spacer member 40. As a result, at least a part of the space in the circumferential direction z between the inner wall of the outer tube 20 and the outer wall of the inner tube 30 in the portion where the spacer member 40 is disposed in the longitudinal axis direction x is filled by the spacer member 40, as shown in Fig. 3 to Fig. 5, Fig. 7, and Fig. 8, while the space inside the outer tube 20 and outside the inner tube 30 proximal to the proximal end of the spacer member 40 can be left unfilled and secured as shown in Fig. 6.

[0032] 4, 7, and 8, the spacer member 40 may be disposed in a portion of the circumferential direction z. In this case, the range that the spacer member 40 occupies in 360° of the circumferential direction z is preferably 45° or more, more preferably 60° or more, and even more preferably 90° or more, and may be 270° or less, 240° or less, 180° or less, etc. If the spacer member 40 is disposed in the circumferential direction z at an angle within such a range, the inner lumen 20a of the outer tube 20 can be easily secured.

[0033] Alternatively, as shown in Fig. 5, the spacer member 40 may be tubular and disposed over the entire circumferential direction z. If the spacer member 40 is tubular and disposed over the entire circumferential direction z, the collapse of the lumen 20a of the outer tube 20 can be more easily prevented. In addition, the lumen 20a of the outer tube 20 is filled over the entire circumferential direction z, i.e., between the inner wall of the distal end tube 50 and the outer wall of the inner tube 30 in the radial direction y, and between the inner wall of the outer tube 20 and the outer wall of the inner tube 30, with the spacer member 40, so that it is possible to prevent unintended intrusion of foreign matter such as blood into the space inside the outer tube 20 and outside the inner tube 30.

[0034] 3 to 5 and 7 to 9, it is preferable that no space is formed on the outside or inside in the radial direction y of the spacer member 40. This makes it easier to prevent deformation of the distal end portion of the catheter 10.

[0035] 3, it is preferable that the thickness of the outer tube 20, i.e., the thickness of the side wall of the outer tube 20, is equal to the thickness of the tip tube 50, i.e., the thickness of the side wall of the tip tube 50. The thickness of the outer tube 20 and the thickness of the tip tube 50 being equal means that there is no step on the outside or inside of the connection portion between the outer tube 20 and the tip tube 50 from the distal end of the outer tube 20 to the proximal end of the tip tube 50. This makes it easier to arrange the spacer member 40 and the cover tube 60 described later.

[0036] 3, a cover tube 60 is disposed on the outside of the tip tube 50 and the outer tube 20 in the radial direction y. This allows the tip tube 50, which is disposed distal to the distal end of the outer tube 20, to be stably connected to the outer tube 20. This improves the connection strength of the tip tube 50 to the distal end of the catheter 10, and prevents the tip tube 50 from falling off the catheter 10.

[0037] The thickness of the cover tube 60, i.e., the thickness of the side wall of the cover tube 60, is preferably thinner than the thickness of the outer tube 20 and the thickness of the tip tube 50. This can improve the flexibility of the distal end portion of the catheter 10.

[0038] The spacer member 40, the tip tube 50, and the cover tube 60 are preferably made of an insulating material, and are preferably made of a resin. The resin constituting the spacer member 40, the tip tube 50, and the cover tube 60 can refer to the resin constituting the outer tube 20 and the inner tube 30.

[0039] The spacer member 40 is preferably made of a material having a higher Shore D hardness than the material of the tip tube 50. Since the spacer member 40 is harder than the tip tube 50, the spacer member 40 can firmly support the inner wall of the tip tube 50 and the outer wall of the inner tube 30, and can easily exert the effect of preventing the gap between the inner wall of the tip tube 50 and the outer wall of the inner tube 30 from shrinking. In addition, since the tip tube 50 is relatively soft, the flexibility of the distal end portion of the catheter 10 can be improved, and the effect of preventing damage to the body cavity wall can be improved.

[0040] The Shore D hardness of the material constituting the spacer member 40 is preferably more than 50, 52 or more, 55 or more, and is preferably 65 or less, 62 or less, or 60 or less. The Shore D hardness of the material constituting the tip tube 50 is preferably 15 or more, 20 or more, 30 or more, or 35 or more, and is preferably 50 or less, 45 or less, or 40 or less. The Shore D hardness can be measured, for example, using a type D durometer based on the description of JIS K6253-2:2012.

[0041] The tip tube 50 may be made of a material having a lower Shore D hardness than the material of the outer tube 20 and the inner tube 30. In this case, the Shore D hardness of the material of the outer tube 20 and the inner tube 30 may be relatively higher than the Shore D hardness of the material of the tip tube 50. For example, the Shore D hardness of the material of the outer tube 20 and the inner tube 30 is preferably 30 or more, 35 or more, 40 or more, 45 or more, or 50 or more, and is preferably 70 or less, 65 or less, or 55 or less. The tip tube 50 is softer than the outer tube 20 and the inner tube 30, so that the flexibility of the distal end of the catheter 10 can be further improved, and the effect of preventing damage to the body cavity wall can be further improved.

[0042] As shown in Fig. 3, in the longitudinal axis direction x, the proximal end of the spacer member 40 is preferably located proximal to the proximal end of the tip tube 50. As a result, the spacer member 40 can fill not only the gap between the inner wall of the tip tube 50 and the outer wall of the inner tube 30, but also the gap between the inner wall at the distal end of the outer tube 20 and the outer wall of the inner tube 30 as shown in Figs. 7 and 8, and more effectively prevent the space inside the outer tube 20 and outside the inner tube 30 from collapsing. As a result, bending of the distal end of the catheter 10 can be more easily prevented.

[0043] As shown in Fig. 9, when the position where the distal end of the outer tube 20 and the proximal end of the tip tube 50 are connected in the longitudinal axis direction x is defined as the reference position A, it is preferable that the length L1 from the proximal end of the spacer member 40 to the reference position A is shorter than the length L2 from the distal end of the spacer member 40 to the reference position A. This makes it possible to prevent the space between the inner wall of the tip tube 50 and the outer wall of the inner tube 30 from being reduced, and to prevent the space inside the outer tube 20 and outside the inner tube 30 from being crushed, without making the length in the longitudinal axis direction x where the spacer member 40 fills the gap between the inner wall of the outer tube 20 and the outer wall of the inner tube 30 too long. Alternatively, the length L1 from the proximal end of the spacer member 40 to the reference position may be the same as or longer than the length L2 from the distal end of the spacer member 40 to the reference position, and it is preferable that L1 is 0.5 times or more, 1 time or more, 1.5 times or more, and 3 times or less, or 2 times or less of L2.

[0044] As shown in Fig. 3, in the longitudinal axis direction x, the distal end of the inner tube 30 is preferably located distal to the proximal end of the tip tube 50. This allows the distal end of the catheter 10 to have a configuration in which three members are stacked in the order of the inner tube 30, the spacer member 40, and the tip tube 50 from the inside in the radial direction y, as shown in Fig. 4 and Fig. 5, making it easier to prevent the distal end of the catheter 10 from shrinking in diameter and becoming deformed.

[0045] 3, the inner tube 30 preferably extends to the distal end of the catheter 10. With this configuration, by forming the inner wall of the inner tube 30 from a fluororesin having high slipperiness, it is possible to improve the ease of insertion of treatment tools such as a guidewire or forceps into the lumen 30a of the inner tube 30.

[0046] The guidewire may be disposed in the lumen 30a of the inner tube 30, and the tip of the guidewire may reach the site to be treated first, and then the catheter 10 may be delivered along the guidewire to the site to be treated, or the catheter 10 may be delivered near the site to be treated first, and then the tip of the guidewire may be delivered to the site to be treated, thereby positioning the distal end of the catheter 10. The guidewire is preferably introduced into the lumen 30a of the inner tube 30 from a guidewire port 72 provided on the catheter 10 through a guidewire tube 71.

[0047] It is preferable that the distal end of the inner tube 30, the distal end of the spacer member 40, and the distal end of the tip tube 50 all extend to the distal end of the catheter 10. This allows the distal end of the catheter 10 to have a configuration in which three members are stacked in this order from the inside in the radial direction y: the inner tube 30, the spacer member 40, and the tip tube 50, making it easier to prevent the distal end of the catheter 10 from shrinking in diameter and becoming deformed.

[0048] The tip tube 50 is preferably made of a material having a lower Shore D hardness than the material constituting the cover tube 60. This allows the cover tube 60 to be relatively hard, and the connection between the outer tube 20 and the tip tube 50 can be more easily stabilized to improve the strength of the distal end of the catheter 10. In addition, in the radial direction y, a hard member (cover tube 60), a soft member (tip tube 50), and a hard member (spacer member 40) can be stacked in this order from the outside of the distal end of the catheter 10, and while the flexibility of the distal end of the catheter 10 is ensured by the soft member (tip tube 50), the strength of the distal end of the catheter 10 is improved by the hard member (cover tube 60), and the catheter 10 can be prevented from bending by the hard member (spacer member 40).

[0049] 3, in the longitudinal axis direction x, the proximal end of the cover tube 60 is preferably located distal to the proximal end of the spacer member 40. This allows the length of the cover tube 60 in the longitudinal axis direction x to be set to a predetermined value or less, so that even if the cover tube 60 is made of a relatively hard material, the flexibility of the distal end of the catheter 10 can be controlled by the material hardness of the cover tube 60 and the spacer member 40.

[0050] It is preferable that the distal end of the cover tube 60, the distal end of the inner tube 30, the distal end of the spacer member 40, and the distal end of the tip tube 50 all extend to the distal end of the catheter 10. This allows the distal end of the catheter 10 to have a configuration in which four members are stacked in the order of the inner tube 30, the spacer member 40, the tip tube 50, and the cover tube 60 from the inside in the radial direction y, and this makes it possible to easily prevent the distal end from being deformed due to diameter reduction while ensuring the strength of the catheter 10.

[0051] It is preferable that the outer surface of the inner tube 30 is welded to the inner surface in the radial direction y of the spacer member 40, the outer surface of the spacer member 40 in the radial direction y is welded to the inner surface of the tip tube 50, and the outer surface of the tip tube 50 is welded to the inner surface of the cover tube 60. This makes it possible to prevent the inner tube 30, the spacer member 40, and the tip tube 50 from shifting from one another or falling off, making it easier to give the distal end of the catheter 10 a stable structure that is less likely to deform.

[0052] As shown in Fig. 10, the catheter 10 is preferably an electrode catheter having a plurality of electrodes 90 arranged at intervals in the longitudinal axis direction x on the outer surface of the distal portion of the outer tube 20. The electrode catheter is used as a medical instrument for diagnosing arrhythmia by measuring the potential of the heart, and for cauterizing body tissue by passing a high-frequency current through the electrodes 90 to treat arrhythmia. In addition, by forming the electrodes 90 into an electrode group, the electrode catheter can also be used as a defibrillation catheter that provides an electrical signal to the heart from the electrode group when atrial fibrillation occurs.

[0053] 11, the electrode 90 is preferably disposed on the outside of a side hole 21 provided in the side wall of the distal part of the outer tube 20 so as to penetrate the outside and inside of the outer tube 20. The electrode 90 can function as a measurement electrode or a reference electrode when measuring a potential, and also as an electrode for passing a high-frequency current or an electrode for applying an electrical signal.

[0054] As an example of the shape of the electrode 90, a ring-shaped form is shown in FIG. 11, but other shapes include a C-shaped cross section with a cut in the ring, a coil-shaped form with a wound wire, and the like. When the electrode 90 has such a shape, the electrode 90 can be arranged on the outer surface of the outer tube 20 by crimping the electrode 90 to the outer tube 20. Alternatively, the electrode 90 may be a flat plate electrode formed independently in an island shape when viewed from the outside of the outer tube 20. The shape of the flat plate electrode may be any shape such as a polygonal shape such as a rectangle or a square, or a circular shape. It is preferable that at least one of the inner surface and the outer surface of such a flat plate electrode is curved so as to easily follow the curved surface of the outer tube 20. Among them, the electrode 90 is preferably ring-shaped. By the electrode 90 being ring-shaped, the area of ​​the electrode 90 on the outer peripheral surface of the outer tube 20 can be increased, and the electrode 90 can be easily brought into contact with a target tissue such as the inner wall of the heart.

[0055] The electrode 90 may be made of any material as long as it is conductive, and may be made of a metal or a mixture containing a metal and a resin. In particular, metals such as platinum, platinum-iridium alloy, stainless steel, and tungsten, or conductive resins, are preferably used as the material for the electrode 90. When the electrode 90 is made of conductive resin, it is preferable to mix a contrast agent such as barium sulfate or bismuth oxide into the electrode 90 so that the electrode 90 can be viewed under X-ray fluoroscopy.

[0056] The number of electrodes 90 is not particularly limited, and may be, for example, 2 or more, 3 or more, 5 or more, 8 or more, 10 or more, or 30 or less, 25 or less, 20 or less, etc. Depending on the purpose of using the electrode catheter, the multiple electrodes 90 may form an electrode group, and the multiple electrode groups may be arranged at intervals in the longitudinal axis direction x.

[0057] The size of each of the multiple electrodes 90 may be the same or different. The different sizes of the electrodes 90 refer to, for example, that the lengths of the electrodes 90 in the longitudinal axis direction x are different.

[0058] 11, a conductor 80 is connected to the electrode 90, and the conductor 80 preferably extends through a side hole 21 provided in the outer tube 20 into the lumen 20a of the outer tube 20 outside the inner tube 30. The conductor 80 preferably extends proximally from the proximal end of the lumen 20a of the outer tube 20 and is connected to a connector 82 through a conductor tube 81. The connector 82 is connected to an external device such as a power source or an electrocardiograph, so that the conductor 80 can electrically connect the electrode 90 to the external device. It is preferable that one conductor 80 is connected to each of the multiple electrodes 90.

[0059] The conductor wire 80 may be any wire that is electrically conductive, and may be, for example, a copper wire, an iron wire, a stainless steel wire, a piano wire, a tungsten wire, a nickel-titanium alloy wire, etc. Among these, a stainless steel wire is particularly preferable because it has linearity and rigidity, making it easy to pass the conductor wire 80 through the side hole 21 of the outer tube 20, and because disconnection at the connection between the conductor wire 80 and the electrode 90 is unlikely to occur.

[0060] Each conductor 80 may be a solid wire or a stranded wire. The cross-sectional shape of each conductor 80 perpendicular to the longitudinal axis direction x may be, for example, a circle, an oval, a polygon, or a combination of these. The major axis of the conductor 80 is not particularly limited, and is preferably 0.05 mm or more, more preferably 0.08 mm or more, even more preferably 0.1 mm or more, and is preferably 0.3 mm or less, more preferably 0.2 mm or less, and even more preferably 0.15 mm or less. The major axis of the conductor 80 means the diameter of a circumscribing circle of the conductor 80 in a cross-section perpendicular to the longitudinal axis direction x, regardless of whether the conductor 80 is a solid wire or a stranded wire, and regardless of the cross-sectional shape.

[0061] The conductor 80 may have a coating material on a portion other than the end connected to the electrode 90. This can prevent short circuiting with adjacent members. The material of the coating material of the conductor 80 may be an insulating material, and examples of the material include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, polyetherpolyamide resins, polyurethane resins, polyimide resins, fluororesins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. Among these, fluororesins are preferable, and PFA is more preferable. By using a fluororesin as the material of the coating material of the conductor 80, the insulation of the conductor 80 can be improved, and the sliding property against other members such as the conductor 80 connected to other electrodes 90 and the inner wall of the outer tube 20 can be improved in the lumen 20a of the outer tube 20, and damage caused by contact of the coating material of the conductor 80 with other parts can be prevented, thereby improving the protective effect of the coating material on the conductor 80.

[0062] The conductive wire 80 and the electrode 90 can be connected by a method such as laser welding, resistance welding, or bonding with an adhesive.

[0063] As shown in Fig. 11, in the longitudinal axis direction x, the proximal end of the spacer member 40 is preferably disposed at the same position as the distal end of the first electrode 91, which is disposed at the most distal side of the multiple electrodes 90, or further distal than the distal end of the first electrode 91. A conductor 80 connected to the electrodes 90 including the first electrode 91 is disposed proximal to the distal end of the first electrode 91, but by disposing the proximal end of the spacer member 40 at the same position as the distal end of the first electrode 91 or further distal than the distal end of the first electrode 91, it is possible to prevent the spacer member 40 from interfering with the conductor 80 connected to the electrode 90. This makes it possible to prevent the deformation or bending of the distal end of the catheter 10 by the spacer member 40 without impairing the function of the conductor 80.

[0064] As shown in Fig. 11, in the longitudinal axis direction x, the length L3 between the proximal end of the spacer member 40 and the distal end of the first electrode 91 is preferably 5 times or less the length of the first electrode 91. This allows the spacer member 40 to be disposed as far as possible on the proximal side without interfering with the conductor 80, so that the length of the portion in which the spacer member 40 is disposed in the longitudinal axis direction x can be increased, and the effect of preventing the distal end of the catheter 10 from bending can be improved. In addition, since the spacer member 40 is disposed as far as possible on the proximal side without interfering with the conductor 80, it is also easier to prevent the lumen 20a of the outer tube 20 proximal to the proximal end of the spacer member 40 from being crushed and deformed.

[0065] From the viewpoint of arranging the spacer member 40 as close as possible to the proximal side, the length L3 is more preferably 4.5 times or less, further preferably 4 times or less, particularly preferably 3 times or less, and may be 2 times or less, 1 time or less, or 0.5 times or less of the length of the first electrode 91 in the longitudinal axis direction. The length L3 may be zero, that is, the proximal end of the spacer member 40 may be disposed at the same position as the distal end of the first electrode 91 that is disposed on the most distal side of the multiple electrodes 90, but from the viewpoint of more easily preventing interference of the spacer member 40 with the conductor 80, the length L3 is preferably 0.1 times or more, more preferably 0.2 times or more, and even more preferably 0.3 times or more of the length of the first electrode 91 in the longitudinal axis direction. [Explanation of symbols]

[0066] 10: Catheter 20: Outer tube 20a: Lumen of outer tube 21: Side hole 30: Inner tube 30a: Lumen of inner tube 40: Spacer member 50: Tip tube 60: Cover tube 70: Handle 71: Guidewire tube 72: Guidewire port 80: Conductor 81: Conductive tube 82: Connector 90: Electrode 91: 1st electrode

Claims

1. A catheter having a longitudinal axis and a radial direction perpendicular to the longitudinal axis, and having a distal end and a proximal end in the longitudinal axis direction, an outer tube having a lumen extending in the longitudinal direction; an inner tube extending into the lumen of the outer tube; a spacer member disposed on an outer side of the inner tube in the radial direction; a tip tube disposed distal to the distal end of the outer tube and disposed radially outward of the spacer member; A catheter comprising the tip tube and a cover tube disposed radially outside the outer tube.

2. 2. The catheter according to claim 1, wherein the spacer member is made of a material having a Shore D hardness higher than that of a material constituting the distal end tube.

3. 3. The catheter according to claim 1, wherein the spacer member is tubular.

4. The catheter according to claim 1 or 2, wherein a proximal end of the spacer member is located proximally relative to a proximal end of the tip tube in the longitudinal axis direction.

5. The catheter according to claim 1 or 2, wherein a distal end of the inner tube is located distal to a proximal end of the tip tube in the longitudinal axis direction.

6. The catheter according to claim 1 or 2, wherein a proximal end of the cover tube is located distal to a proximal end of the spacer member in the longitudinal axis direction.

7. 3. The catheter according to claim 1, wherein the tip tube is made of a material having a Shore D hardness lower than that of a material constituting the cover tube.

8. 3. A catheter as described in claim 1 or 2, wherein the outer surface of the inner tube is welded to the radially inner surface of the spacer member, the radially outer surface of the spacer member is welded to the radially inner surface of the tip tube, and the outer surface of the tip tube is welded to the radially inner surface of the cover tube.

9. 3. The catheter according to claim 1, wherein the catheter is an electrode catheter having a plurality of electrodes spaced apart in the longitudinal direction on the outer surface of the distal portion of the outer tube.

10. 10. The catheter according to claim 9, wherein, in the longitudinal axis direction, a proximal end of the spacer member is disposed at the same position as a distal end of a first electrode that is disposed most distally among the plurality of electrodes, or distal to the distal end of the first electrode.

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