Catheter

Abstract

To provide a catheter which easily pierces a biological membrane, allows a user to confirm a position of the distal end of the catheter in a body lumen, and reduces the number of steps which are performed by an operator.SOLUTION: A catheter 1 comprises: a resin tube 10; and a guide wire member 20 which has a tip end chip 21, a coil 22, and a core wire 23, and moves relative to the resin tube 10 in a longitudinal direction x. In a first state in which, after moving the guide wire member 20 to the distal side so that the proximal end 22p of the coil 22 is positioned on the furthest side relative to the resin tube 10, a load other than gravity is not applied to the coil 22, the coil 22 has a first zone 227 where the coil is arranged in the lumen 13 of the resin tube 10, and a second zone 228 where the coil protrudes from the distal end 10d of the resin tube 10. An average of a pitch P2p of the proximal part of the second section 228 is larger than an average of a pitch P2d of the distal part of the second section 228.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a catheter for puncturing a biological membrane. [Background technology]

[0002] Catheters equipped with electrodes are used for the examination and treatment of arrhythmias such as atrial fibrillation (AF) and atrioventricular reentrant tachycardia (AVRT). During examinations, such catheters are inserted into the cardiac chambers and the electrodes measure the intracardiac potential to identify the abnormal part of the heart that is causing the arrhythmia. During treatment, the electrodes are used to apply energy including high-frequency current to the abnormal part of the heart that is causing the arrhythmia. This causes the source of the arrhythmia to necrose and is electrically isolated from the heart. This technique is generally called ablation surgery. During examinations and treatments, atrial fibrillation may occur naturally or may be induced to identify the abnormal part of the heart. In such cases, defibrillation is performed by applying an electrical stimulus to the heart from the electrodes.

[0003] In ablation surgery, the surgeon must move the catheter from the patient's right atrium to the left atrium. The Brockenbrough technique is used to achieve this. The Brockenbrough technique is a method in which a septal needle (also called a Brockenbrough needle) is inserted from the right atrium into the fossa ovalis in the septum of the atrium, forming a path for the catheter to enter the left atrium.

[0004] More specifically, while checking the positions of the septal puncture needle and the fossa ovalis by ultrasound or X-ray irradiation, the tip of the septal puncture needle is pressed against the fossa ovalis, the fossa ovalis is cauterized by passing an electric current through the septal puncture needle, and the septal puncture needle penetrates the fossa ovalis. With the septal puncture needle penetrating the fossa ovalis, a liquid such as physiological saline or contrast agent is poured from the tip of the septal puncture needle, and by checking that the liquid flows into the left atrium using ultrasound or X-ray irradiation, it is possible to check whether a hole communicating the right atrium and the left atrium has been formed in the fossa ovalis.

[0005] For example, Patent Document 1 describes a puncture device having a resin tube having a distal end and a proximal end and extending in the longitudinal direction, a metal tube disposed in the lumen of the resin tube, a metal core material joined to the distal end of the metal tube, and a metal tip joined to the distal end of the metal core material. The puncture device has a liquid flow path between the inner surface of the resin tube and the outer surface of the metal core material, the flow path communicating with the lumen of the metal tube, and the resin tube has an opening on its side that communicates the flow path with the outside of the resin tube. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2022 / 102319 Summary of the Invention [Problem to be solved by the invention]

[0007] When using the puncture device described in Patent Document 1, the surgeon first inserts a guidewire into the body, and then inserts a sheath into the body along the guidewire. After removing the guidewire, the surgeon inserts the puncture device into the lumen of the sheath and transports the puncture device to the area to be treated. As described above, the surgeon must perform many steps with conventional puncture devices, and therefore there has been a demand for the development of a device that requires fewer steps.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a catheter that can easily penetrate biological membranes and enable the position of the distal end of the catheter within a body cavity to be confirmed, while reducing the number of steps required by the surgeon compared to conventional methods. [Means for solving the problem]

[0009] A catheter according to one embodiment of the present invention is as follows. [1] A resin tube having a longitudinal direction, a distal end and a proximal end in the longitudinal direction, and an inner lumen extending from the distal end to the proximal end; a guide wire member including a distal tip, a coil wound with a wire having a first end and a second end located proximal to the first end, the first end of the wire being connected to the distal tip, and a core wire connected to the distal tip and disposed in an inner cavity of the coil, the guide wire member moving in the longitudinal direction relative to the resin tube; a catheter in which, in a first state in which no load other than gravity is applied to the coil after the guidewire member is moved distally so that the proximal end of the coil is positioned at the distal end relative to the plastic tube, the coil has a first section disposed in the inner cavity of the plastic tube and a second section protruding from the distal end of the plastic tube, and when the length of the second section is divided in half in the longitudinal direction, the distal side is called the distal second section and the proximal side is called the proximal second section, the average pitch of the proximal second section is greater than the average pitch of the distal second section.

[0010] In the above catheter, the direction of travel of the guidewire member can be easily adjusted by moving the core wire to the distal side or the proximal side. That is, the guidewire member can function as a so-called guidewire. Also, when the core wire is moved proximally with respect to the proximal end of the coil, the second section of the coil shrinks and the pitch becomes smaller. This increases the rigidity of the distal end of the guidewire member, and the distal tip can pierce the biological membrane. That is, the guidewire member can function as a so-called puncture needle by adjusting the coil pitch. Here, since the average pitch of the proximal second section of the coil is greater than the average pitch of the distal second section in the first state, the rigidity of the distal second section is increased compared to the proximal second section. Therefore, the coil can be stably operated when piercing the biological membrane with the distal tip. Also, since the average pitch is set in this way, the liquid such as physiological saline or contrast medium that has passed through the lumen of the coil can be discharged from between the adjacent wires at least in the proximal second section of the coil. The position of the catheter inside the body can be confirmed by observing the state of the liquid being discharged using ultrasound or X-ray irradiation. This eliminates the need for the conventional process of removing the guidewire and then inserting a puncture needle, reducing the number of steps that the surgeon must take compared to conventional processes.

[0011] The catheter according to the embodiment of the present invention preferably satisfies the following items [2] to [9]. [2] A catheter as described in [1], wherein in the first state, the average pitch of the coil in the proximal second section is greater than the average pitch of the first section. [3] A catheter as described in [1] or [2], wherein in the first state, the average pitch of the coil in the distal second section is greater than the average pitch of the first section. [4] The catheter according to any one of [1] to [3], wherein in the first state, the proximal second section is configured to be able to come into contact with a biological membrane. [5] A catheter described in any one of [1] to [4], wherein, after the guide wire member is moved proximally so that the proximal end of the coil is positioned most proximal relative to the resin tube, in a second state in which no load other than gravity is applied to the coil, the distal end of the tip chip is at the same position as the distal end of the resin tube or at a position proximal to the distal end of the resin tube. [6] The catheter according to any one of [1] to [5], wherein in the first state, adjacent wires are in close contact with each other in the distal second section of the coil. [7] The catheter described in any one of [1] to [6], wherein in the first state, there are gaps between adjacent wires in the proximal second section of the coil. [8] The catheter described in any one of [1] to [7], wherein in the first state, the second section has a curved or bent shape. [9] A catheter as described in [8], wherein in a third state, the guide wire member is moved distally so that the proximal end of the coil is positioned most distally relative to the plastic tube, and then the core wire is moved proximally relative to the proximal end of the coil so that the distal end of the core wire is positioned most proximal, so that the second section has a straight shape. Effect of the Invention

[0012] The above catheter has a guidewire member that can function as both a guidewire and a puncture needle, and can also eject liquids such as saline, contrast medium, etc. This eliminates the need for the conventional process of inserting a puncture needle after removing the guidewire, thereby reducing the number of steps performed by the surgeon compared to conventional processes. [Brief description of the drawings]

[0013] [Figure 1]FIG. 1 is a side view (partial cross-sectional view) of a catheter according to an embodiment of the present invention, showing a first state in which no load other than gravity is applied to the coil after the guidewire member has been moved distally so that the proximal end of the coil is positioned at the most distal side relative to the resin tube. [Diagram 2] FIG. 2 is a side view (partial cross-sectional view) showing a second state in which no load other than gravity is applied to the coil in the catheter shown in FIG. 1 after the guidewire member has been moved proximally so that the proximal end of the coil is positioned most proximal relative to the resin tube. [Diagram 3] FIG. 2 is a side view (partial cross-sectional view) showing a third state in which, in the catheter shown in FIG. 1, the guide wire member is moved distally so that the proximal end of the coil is positioned most distally relative to the resin tube, and then the core wire is moved proximally relative to the proximal end of the coil so that the distal end of the core wire is positioned most proximal. [Figure 4] 1. FIG. 4 is a side view (partially in cross section) showing a modification of the first state of the catheter shown in FIG. [Diagram 5] 1. FIG. 4 is a side view (partially in cross section) showing another modified example of the catheter in the first state shown in FIG. [Figure 6] 1. FIG. 4 is a side view (partially in cross section) showing still another modified example of the catheter in the first state shown in FIG. [Figure 7] 4 is a side view (partially in cross section) showing a modification of the second state of the catheter shown in FIG. 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the illustrated examples, and can be modified appropriately within the scope of the above and below, and all of these are included in the technical scope of the present invention. In each drawing, hatching and symbols may be omitted for convenience, but in such cases, the specification and other drawings should be referred to. In addition, the dimensions of various parts in the drawings may differ from the actual dimensions, since priority is given to helping understand the features of the present invention.

[0015] A catheter according to an embodiment of the present invention includes a resin tube having a longitudinal direction, a distal end and a proximal end in the longitudinal direction, and an inner cavity extending from the distal end to the proximal end, a distal tip, a coil wound with a wire having a first end and a second end located proximal to the first end, the first end of the wire being connected to the distal tip, and a core wire connected to the distal tip and disposed in the inner cavity of the coil, and a guide wire member that moves in the longitudinal direction relative to the resin tube, and a proximal end of the coil. After the guide wire member is moved distally so that its end is positioned most distal relative to the plastic tube, in a first state in which no load other than gravity is applied to the coil, the coil has a first section disposed in the inner cavity of the plastic tube and a second section protruding from the distal end of the plastic tube, and when the length of the second section is divided in half in the longitudinal direction, the distal side is called the distal side second section and the proximal side is called the proximal side second section, and the gist of the invention is that the average pitch of the proximal side second section is greater than the average pitch of the distal side second section.

[0016] The overall configuration of a catheter according to an embodiment of the present invention will be described with reference to Figs. 1 to 7. Fig. 1 is a side view (partially sectional) of a catheter according to an embodiment of the present invention, showing a first state. Fig. 2 is a side view (partially sectional) of the catheter shown in Fig. 1, showing a second state. Fig. 3 is a side view (partially sectional) of the catheter shown in Fig. 1, showing a third state. Figs. 4 to 6 are side views (partially sectional) of modified examples of the catheter shown in Fig. 1 in the first state. Fig. 7 is a side view (partially sectional) of a modified example of the catheter shown in Fig. 2 in the second state. The catheter 1 comprises a resin tube 10 and a guidewire member 20. The guidewire member 20 has a distal tip 21, a coil 22, and a core wire 23.

[0017] As shown in FIG. 1 to FIG. 7, the resin tube 10 has a longitudinal direction x, a distal end 10d and a proximal end 10p in the longitudinal direction x, and an inner lumen 13 extending from the distal end 10d to the proximal end 10p. The resin tube 10 preferably has a radial direction perpendicular to the longitudinal direction x and a circumferential direction along the outer circumference. The catheter 1, like the resin tube 10, preferably has a longitudinal direction x, a radial direction, and a circumferential direction. In this specification, the direction toward the user's hand in the longitudinal direction x is referred to as the proximal side, and the opposite side to the proximal side, i.e., the direction toward the treatment target, is referred to as the distal side. The longitudinal direction x can also be referred to as the near-far direction or the extending direction of the resin tube 10. The radial direction refers to the radial direction of the resin tube 10, the inward direction in the radial direction of the resin tube 10 refers to the direction toward the longitudinal central axis of the resin tube 10, and the outward direction in the radial direction refers to the direction extending radially from the longitudinal central axis opposite to the inward direction. In this drawing, the left side of the drawing is the distal side and the right side of the drawing is the proximal side.

[0018] As shown in Figs. 1 to 7, the guidewire member 20 has a distal tip 21, a coil 22, and a core wire 23. The coil 22 is formed by winding a wire 220. The wire 220 has a first end and a second end. The second end is located proximal to the first end. The first end of the wire 220 is connected to the distal tip 21. The core wire 23 is connected to the distal tip 21 and is disposed in the inner cavity 223 of the coil 22. The guidewire member 20 moves in the longitudinal direction x with respect to the resin tube 10. The distal tip 21 is a member provided at the distal portion of the guidewire member 20. The distal tip 21 is preferably provided at a first end of the guidewire member 20.

[0019] 1 and 4 to 6, in a first state in which no load other than gravity is applied to the coil 22 after the guidewire member 20 is moved distally so that the proximal end 22p of the coil 22 is located at the most distal side with respect to the resin tube 10, the coil 22 has a first section 227 disposed in the lumen 13 of the resin tube 10 and a second section 228 protruding from the distal end 10d of the resin tube 10. In addition, when the length of the second section 228 is divided into two equal parts in the longitudinal direction x, the distal side is defined as the distal second section 228d and the proximal side is defined as the proximal second section 228p, the average pitch P2p of the proximal second section 228p is larger than the average pitch P2d of the distal second section 228d.

[0020] In the catheter 1, the moving direction of the guidewire member 20 can be easily adjusted by moving the core wire 23 to the distal side or the proximal side. That is, the guidewire member 20 can function as a so-called guidewire. Also, when the core wire 23 is moved proximally with respect to the proximal end 22p of the coil 22, the second section 228 of the coil 22 is contracted and the pitch becomes smaller. This increases the rigidity of the distal end of the guidewire member 20, and the distal tip 21 can pierce the biological membrane. That is, the guidewire member 20 can function as a so-called puncture needle by adjusting the pitch of the coil 22. Here, in the first state of the coil 22, the average pitch P2p of the proximal second section 228p is larger than the average pitch P2d of the distal second section 228d, so that the rigidity of the distal second section 228d is increased compared to the proximal second section 228p. This allows the coil 22 to be stably operated when the distal tip 21 pierces the biological membrane. In addition, because the average pitch is set in this manner, liquid such as physiological saline or contrast medium that has passed through lumen 223 of coil 22 can be discharged from between adjacent wires 220 at least in proximal second section 228p of coil 22. The position of the catheter in the body can be confirmed by observing the state in which the liquid is discharged using ultrasound or X-ray irradiation. This makes it unnecessary to perform the conventional process of inserting a puncture needle after removing the guidewire, thereby reducing the number of steps performed by the surgeon compared to the conventional process.

[0021] In this specification, the first state refers to a state in which the guidewire member 20 is moved distally so that the proximal end 22p of the coil 22 is located most distally relative to the resin tube 10, and then no load other than gravity is applied to the coil 22. The second state refers to a state in which the guidewire member 20 is moved proximally so that the proximal end 22p of the coil 22 is located most proximal relative to the resin tube 10, and then no load other than gravity is applied to the coil 22. The third state refers to a state in which the guidewire member 20 is moved distally so that the proximal end 22p of the coil 22 is located most distally relative to the resin tube 10, and then the core wire 23 is moved proximally relative to the proximal end 22p of the coil 22 so that the distal end of the core wire 23 is located most proximal.

[0022] In this specification, the pitch refers to the distance between the central axes of adjacent wire rods 220 when the coil 22 is viewed in the radial direction, and refers to the portion having the longest length. For example, as shown in Figs. 5 to 6, when the length of the distance between the central axes of adjacent wire rods 220 varies depending on the radial position of the coil 22 due to the core wire 23 being curved or bent in a state where no load other than gravity is applied to the coil 22, the length measured at the position where the distance is the longest is taken as the pitch between the adjacent wire rods 220. When calculating the average pitch of each section, the pitch, which is the longest distance between the central axes of adjacent wire rods 220, is measured for each pair of adjacent wire rods 220, and the sum of all the measured pitches is divided by the number of distances between adjacent wire rods 220 when viewed in the radial direction (the number of turns of the coil 22 minus 1). To explain an extreme example, for example, when the number of turns in the first section 227 of the coil 22 is 4 when viewed from the radial direction, the pitches P11, P12, and P13, which are the distance between the central axes of adjacent wire rods 220, are obtained, and the sum P11+P12+P13 of all the measured pitches is divided by the number of distances between adjacent wire rods 220, which is 3, to obtain the average pitch P1 of the first section 227. The average pitch P2d of the distal second section 228d and the average pitch P2p of the proximal second section 228p can also be obtained in a similar manner. Note that, when the boundary between the sections is located between the central axes of two adjacent wire rods 220, the distance between the two adjacent wire rods 220 is not taken into consideration when obtaining the average pitch. For example, when the boundary between the distal second section 228d and the proximal second section 228p is located between the central axes of adjacent wires 220 as shown in FIG. 5, the spacing P0 between the two adjacent wires 220 is not used in calculating the average pitch.

[0023] Compared to the case where the average pitch P2d of the distal second section 228d and the average pitch P2p of the proximal second section 228p are the same, the catheter 1 requires a smaller amount of retraction of the core wire 23 proximally relative to the resin tube 10 when transitioning from the first state in Fig. 1 to the third state in Fig. 3. This allows the catheter 1 to be quickly prepared for use as a puncture needle.

[0024] In the second state, the distal end 21d of the tip 21 is preferably in the same position as the distal end 10d of the resin tube 10 or in a position more proximal than the distal end 10d of the resin tube 10. Fig. 2 shows an example in which the distal end 21d of the tip 21 is in a position more proximal than the distal end 10d of the resin tube 10. By determining the movement range of the guidewire member 20 in this manner, it is possible to prevent the guidewire member 20 from coming into contact with non-target tissue during transport of the catheter 1.

[0025] As shown in FIG. 7, in the second state, the distal end 21d of the tip chip 21 may be located distal to the distal end 10d of the resin tube 10. In addition, in the second state, the distal second section 228d of the coil 22 may protrude from the distal end 10d of the resin tube 10. In that case, it is preferable that the proximal second section 228p of the coil 22 is disposed in the lumen 13 of the resin tube 10. When the guidewire member 20 is moved to the most proximal side with respect to the resin tube 10, the distal second section 228d of the coil 22 is exposed from the resin tube 10, so that the catheter 1 can be used as a puncture needle. By protruding the distal second section 228d from the resin tube 10, the proximal second section 228p, which has a lower rigidity than the distal second section 228d in the first state, can be easily accommodated in the resin tube 10. By housing the proximal second section 228p within the resin tube 10, the radially outward side of the coil in the proximal second section 228p can be reinforced by the resin tube 10. This makes it easier to stably manipulate the coil 22 when penetrating the biological membrane with the distal tip 21.

[0026] As shown in Figures 5 and 6, in the first state, when the coil 22, for example the second section 228 of the coil 22, has a curved or bent shape, the position of the distal end 21d of the tip chip 21 and the position of the distal end of the coil 22 may differ between the first state and the second state.

[0027] The first state can also be said to be a state in which the guidewire member 20 protrudes from the distal end 10d of the resin tube 10. In the first state, it is preferable that the guidewire member 20 protrudes from the distal end 10d of the resin tube 10 and is exposed to the outside of the resin tube 10.

[0028] In the first state, there is a gap between adjacent wires 220 in at least the proximal second section 228p. For this reason, in the first state, it is preferable to eject liquid from between adjacent wires 220 in the second section 228 of the coil 22.

[0029] 1, in the first state, the proximal second section 228p of the coil 22 is preferably configured to be capable of contacting the biological membrane. This makes it easier for liquid discharged from between adjacent wires 220 in the proximal second section 228p to come into contact with the biological membrane. In the first state, the entire proximal second section 228p of the coil 22 may be capable of contacting the biological membrane, or only a part of the proximal second section 228p of the coil 22 may be capable of contacting the biological membrane.

[0030] In the first state, the distal second section 228d of the coil 22 may be configured to be capable of contacting the biological membrane. This makes it easier for liquid discharged from between adjacent wires 220 in the distal second section 228d to come into contact with the biological membrane. In the first state, the entire distal second section 228d of the coil 22 may be capable of contacting the biological membrane, or only a part of the distal second section 228d of the coil 22 may be capable of contacting the biological membrane.

[0031] The resin tube 10 may have multiple lumen, but preferably has only one lumen 13 as shown in Fig. 1. In other words, the resin tube 10 preferably has a mono-tubular shape. Examples of the shape of the resin tube 10 include a hollow cylinder and a hollow polygonal column. In the radial direction, the resin tube 10 preferably has an outer surface 14 facing the outside of the resin tube 10 and an inner surface 15 facing the lumen 13.

[0032] Since the resin tube 10 is inserted into the body, it is preferable that the resin tube 10 has flexibility, which allows the resin tube 10 to be deformed to conform to the shape of the body cavity. In addition, it is preferable that the resin tube 10 has elasticity in order to maintain its shape.

[0033] The resin tube 10 can be manufactured by, for example, extrusion molding. The resin tube 10 can be made of a single layer or multiple layers. A part of the resin tube 10 in the longitudinal direction x or circumferential direction may be made of a single layer, and the other part may be made of multiple layers.

[0034] The resin tube 10 can be made of synthetic resins such as polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyether polyamide resins, polyurethane resins, polyimide resins, fluororesins (e.g., PTFE, PFA, ETFE), etc. These may be used alone or in combination of two or more.

[0035] It is preferable that a lubricating coating layer containing PTFE, PFA, etc. is formed on the outer surface of the resin tube 10. This makes it easier to insert the resin tube 10 into a body cavity.

[0036] The length of the resin tube 10 from the distal end 10d to the proximal end 10p can be, for example, 100 mm or more, 150 mm or more, 200 mm or more, etc. The length of the resin tube 10 from the distal end 10d to the proximal end 10p can be, for example, 2400 mm or less, 2350 mm or less, 2300 mm or less, etc.

[0037] The outer diameter of the resin tube 10 can be, for example, 0.25 mm or more, 0.36 mm or more, 0.64 mm or more, etc. The outer diameter of the resin tube 10 can be, for example, 1.28 mm or less, 0.95 mm or less, 0.82 mm or less, etc.

[0038] The guidewire member 20 may be made of synthetic resins such as polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyetherketone resins (e.g., PEEK), polyetherpolyamide resins, polyurethane resins, polyimide resins, and fluororesins (e.g., PTFE, PFA, and ETFE), or metals such as stainless steel, carbon steel, and nickel-titanium alloys. These may be used alone or in combination of two or more. The distal tip 21, coil 22, and core wire 23 constituting the guidewire member 20 may be made of the same material or different materials. When a high-frequency electric field is applied to the distal tip 21, it is preferable that the distal tip 21 is made of a conductive material.

[0039] It is preferable that the guidewire member 20 and the resin tube 10 are not fixed to each other. This allows the guidewire member 20 to move in the longitudinal direction x relative to the resin tube 10. It is preferable that the guidewire member 20 is not fixed to the resin tube 10 over the entire longitudinal direction x.

[0040] The catheter 1 may be provided with a structure for fixing the relative positions of the guidewire member 20 and the resin tube 10 when the guidewire member 20 is moved distally so that the proximal end 22p of the coil 22 is located at the most distal side relative to the resin tube 10. For example, as shown in FIG. 1, the guidewire member 20 may be disposed at the proximal end of the coil 22 and have a protruding portion 24 protruding radially outward. The protruding portion 24 may be disposed over the entire circumferential direction of the coil 22. The protruding portion 24 may come into contact with the proximal end of the resin tube 10 when the guidewire member 20 is moved distally so that the proximal end 22p of the coil 22 is located at the most distal side relative to the resin tube 10.

[0041] The protrusion 24 is preferably fixed to the proximal end of the coil 22. The protrusion 24 may be fixed to the inner surface, the outer surface, or both the inner surface and the outer surface of the coil 22. Although not shown, the protrusion 24 may be provided on the proximal portion of a tubular member, and the distal portion of the tubular member may be inserted into the lumen 223 of the coil 22, thereby disposing the protrusion 24 on the proximal end of the coil 22.

[0042] The protrusion 24 may be fixed to the coil 22 by a method such as adhesion with an adhesive or welding.

[0043] The material constituting the protrusion 24 may be any of the materials listed as the materials for the resin tube 10, the guide wire member 20, or the first handle 31 and the second handle 32 described below.

[0044] In the longitudinal direction x, it is preferable that the second section 228 of the coil 22 is shorter than the first section 227. By forming the coil 22 in this manner, it is possible to reduce the amount of retraction of the core wire 23 when the catheter 1 is used as a puncture needle, and to stably perform the puncture operation into the biological membrane.

[0045] The length from the first end of the guidewire member 20 to the second end of the guidewire member 20 can be, for example, 100 mm or more, 150 mm or more, 200 mm or more, 250 mm or more, etc. The length from the first end of the guidewire member 20 to the second end of the guidewire member 20 can be, for example, 2500 mm or less, 2400 mm or less, 2350 mm or less, 2300 mm or less, etc.

[0046] As shown in FIG. 1, the tip 21 preferably has a distal end 21d and a proximal end 21p. The tip 21 preferably has a first end 211 and a second end 212 in the longitudinal axis direction of the coil 22, and the second end 212 is located closer to the proximal end 22p of the coil 22 than the first end 211. As shown in FIG. 1, not only the embodiment in which the first end 211 and the distal end 21d of the tip 21 are located at the same position, but also the embodiment in which the first end 211 of the tip 21 is located proximal to the distal end 21d as shown in FIG. 5 to FIG. 6 is acceptable. In FIG. 5, the first end 211 of the tip 21 is located at the same position as the proximal end 21p.

[0047] The shape of the tip 21 may be, for example, a cylindrical shape, a conical shape, a truncated conical shape, a polygonal column shape, a polygonal pyramid shape, a polygonal pyramid truncated pyramid shape, a sphere shape, a hemisphere shape, or the like.

[0048] It is preferable that the tip chip 21 is not indirectly or directly fixed to the distal end 10d of the resin tube 10. For example, it is preferable that the tip chip 21 is not fixed to the distal end 10d of the resin tube 10 via another member, an adhesive, or the like. It is preferable that the tip chip 21 is not fixed to the distal end 10d of the resin tube 10 by welding.

[0049] The wire 220 of the coil 22 is preferably arranged so as to wind around the core wire 23. The coil 22 has a helical shape. The inner cavity 223 of the coil 22 is formed by the wire 220 being arranged in a helical shape. In the radial direction, the coil 22 preferably has an outer surface facing the resin tube 10 and an inner surface facing the inner cavity 223 of the coil 22.

[0050] The wire diameter of the wire 220 constituting the coil 22 and the number of turns of the wire 220 are not particularly limited. For example, the wire diameter of the wire 220 can be 0.05 mm or more, 0.10 mm or more, etc. The wire diameter of the wire 220 can be 0.50 mm or less, 0.40 mm or less, etc. The number of turns of the wire 220 can be 250 or more, 300 or more, etc. The number of turns of the wire 220 can be 60,000 or less, 55,000 or less, etc.

[0051] Coil 22 may be a single-layer wound coil, a multi-layer wound coil, or a combination of these. For example, Figs. 1 to 7 show an example in which coil 22 is a single-layer wound coil.

[0052] Wire 220 constituting coil 22 may be composed of a single linear member from the first end to the second end, or wire 220 may be composed of multiple linear members connected to each other in the longitudinal direction.

[0053] In the first state, the pitches P1 of the first section 227 of the coil 22 may all be the same width, or some of the pitches P1 may have different widths.

[0054] In the first state, the pitch P1 of the first section 227 is preferably the same length as the wire diameter of the wire 220, and more preferably, the entire pitch P1 of the first section 227 is the same length as the wire diameter of the wire 220. In addition, in the first state, it is more preferable that the adjacent wires 220 of the coil 22 are in close contact with each other in the first section 227. That is, in the first state, it is more preferable that the adjacent wires 220 of the coil 22 are not spaced apart from each other in the first section 227. This makes it easier for liquid to pass through the inner cavity 223 of the coil 22 from the proximal side to the distal side. Note that an embodiment in which only a part of the pitch P1 of the coil 22 in the first section 227 in the first state is the same length as the wire diameter of the wire 220 is also acceptable.

[0055] In the first state, all pitches P2d of the distal second section 228d of the coil 22 may have the same width, or some pitches P2d may have different widths.

[0056] As shown in FIG. 1, in the first state, the pitch P2d of the distal second section 228d of the coil 22 is preferably the same length as the wire diameter of the wire 220, and more preferably, the entire pitch P2d of the distal second section 228d of the coil 22 is the same length as the wire diameter of the wire 220. Also, as shown in FIG. 1, in the first state, it is more preferable that the adjacent wires 220 are in close contact with each other in the distal second section 228d of the coil 22. That is, in the first state, it is more preferable that there is no gap between the adjacent wires 220 in the distal second section 228d of the coil 22. This increases the rigidity of the distal second section 228d, so that the coil 22 can be stably operated when the distal tip 21 penetrates the biological membrane. Note that an embodiment in which only a part of the pitch P2d of the coil 22 in the distal second section 228d in the first state is the same length as the wire diameter of the wire 220 is also acceptable.

[0057] As shown in Fig. 4, in the first state, there may be gaps between adjacent wires 220 in the distal second section 228d of the coil 22. Even if there are gaps between adjacent wires 220, the average pitch P2p of the proximal second section 228p is larger than the average pitch P2d of the distal second section 228d, so that the retraction amount of the core wire 23 is small when transitioning from the first state to the third state, and the coil 22 can be stably operated when penetrating the biological membrane. In addition, by having gaps between adjacent wires 220 in the distal second section 228d, the liquid that has passed through the lumen 223 of the coil 22 in the first state can be discharged from between adjacent wires 220 in the proximal second section 228p.

[0058] In the first state, the coil 22 may have all the pitches P2p of the proximal second section 228p having the same width, or some of the pitches P2p may have different widths.

[0059] As shown in FIG. 1 and FIG. 4, in the first state, it is preferable that there is a gap between adjacent wires 220 in the proximal second section 228p of the coil 22. That is, in the first state, it is preferable that adjacent wires 220 of the coil 22 are not in close contact with each other in the proximal second section 228p. For example, in the first state, the pitch P2p of the proximal second section 228p can be 1.5 times or more, 1.8 times or more, 2.0 times or more, etc., of the wire diameter of the wire 220. In the first state, the pitch P2p of the proximal second section 228p can be 10.0 times or less, 8.0 times or less, 5.0 times or less, etc., of the wire diameter of the wire 220. In the first state, only a part of the pitch P2p of the proximal second section 228p may be within the above numerical range, but it is preferable that all of the pitches P2p of the proximal second section 228p are within the above numerical range. This makes it possible to easily expel the liquid that has passed through the inner cavity 223 of the coil 22 from the proximal side to the distal side from between the adjacent wires 220 in the proximal second section 228p.

[0060] 1, in the first state, it is preferable that the average pitch P2p of the proximal second section 228p of the coil 22 is larger than the average pitch P1 of the first section 227. This makes it easier for liquid to pass from the proximal side to the distal side in the inner cavity 223 of the coil 22, while making it easier for liquid to be discharged from between adjacent wires 220 in the proximal second section 228p.

[0061] 4, in the first state, it is preferable that the average pitch P2d of the distal second section 228d of the coil 22 is greater than the average pitch P1 of the first section 227. This increases the rigidity of the distal second section 228d, making it easier to stably manipulate the coil 22 when penetrating the biological membrane, and also enabling liquid to be ejected from between adjacent wires 220 in the distal second section 228d.

[0062] In the first state, it is preferable that adjacent wires 220 of the coil 22 in the distal second section 228d are in close contact with each other, and that adjacent wires 220 of the coil 22 in the proximal second section 228p have gaps therebetween.

[0063] The core wire 23 is a member for adjusting the pitch of the coil 22. The pitch of the coil 22 can be reduced by pulling the core wire 23 proximally, and the pitch can be restored to its original size by returning the core wire 23 to the distal side. The core wire 23 preferably extends in the longitudinal direction x of the resin tube 10. The shape of the core wire 23 is preferably, for example, linear.

[0064] There is no particular limitation on the wire diameter of the linear member constituting the core wire 23. For example, the wire diameter of the linear member may be 0.10 mm or more, 0.15 mm or more, etc. The wire diameter of the linear member may be 0.80 mm or less, 0.60 mm or less, etc.

[0065] The core wire 23 has a first end and a second end. The second end is located proximal to the first end. It is preferable that the first end of the core wire 23 is connected to the distal tip 21, and it is more preferable that the first end of the core wire 23 is connected to the distal tip 21. From the viewpoint of facilitating manipulation of the position of the core wire 23 relative to the coil 22, it is preferable that in the first state, the second end of the core wire 23 is located proximal to the proximal end 22p of the coil 22.

[0066] 1, in the first state, the distal end 21d of the tip chip 21 may be located distal to the distal end of the wire 220. In addition, in the first state, the guidewire member 20 may extend linearly or along the longitudinal direction x of the resin tube 10.

[0067] 5 to 6, in the first state, the second section 228 preferably has a curved or bent shape. When the second section 228 has such a shape, a portion of the coil 22 that has a relatively low rigidity can be easily positioned at the distal end of the catheter 1, thereby reducing the risk of damaging non-target tissue.

[0068] As shown in FIG. 5, the second section 228 of the coil 22 may be folded back in the longitudinal direction x in the first state. As a result, the first end 211 of the tip tip 21 may face the proximal side in the first state. In FIG. 5, the curved portion of the second section 228 protrudes toward the distal side, and the second section 228 has a J-shape. Also, as shown in FIG. 6, the second section 228 of the coil 22 may be bent in the first state. As a result, the first end 211 of the tip tip 21 may face radially outward in the first state. In FIG. 6, the second section 228 has an L-shape. By providing the second section 228 of the coil 22 with a curved or bent shape in this way, the pitch of the second section 228 can be increased, making it easier to eject liquid from between the adjacent wires 220 in the second section 228 in the first state.

[0069] In a third state in which the guidewire member 20 is moved distally so that the proximal end 22p of the coil 22 is located most distally relative to the resin tube 10, and then the core wire 23 is moved proximally relative to the proximal end 22p of the coil 22 so that the distal end of the core wire 23 is located most proximally, the second section 228 may be linear. As can be seen from Figs. 5 to 6 and 3, it is preferable that the second section 228 of the coil 22 having a curved or bent shape in the first state is linear in the third state. It is more preferable that the entire second section 228 is linear in the third state. The linear shape of the second section 228 makes it easier to stably operate the coil 22 when penetrating a biological membrane.

[0070] In the first state, first section 227 is preferably linear, and more preferably the entire first section 227 is linear. Forming first section 227 in this manner makes it easier to adjust the pitch by retracting core wire 23 and provides rigidity to first section 227, making it easier to stably manipulate coil 22 when penetrating a biological membrane.

[0071] As shown in Figs. 1 to 7, a first handle 31 may be connected to the proximal portion of the catheter 1. The position of the resin tube 10 relative to the guidewire member 20 may be changed by moving the first handle 31 in the longitudinal direction x. In another embodiment, the first handle 31 may have a first operating part for changing the position of the resin tube 10 relative to the guidewire member 20. Examples of the first operating part include a button and a dial. By operating the first operating part, for example by pressing a button or turning a dial, the resin tube 10 can be moved distally or proximally relative to the guidewire member 20.

[0072] The first handle 31 is preferably fixed to the radially outer side of the resin tube 10. The first handle 31 is preferably fixed to the proximal portion of the resin tube 10. For example, as shown in Fig. 1, the first handle 31 may be configured to be a hollow cylinder having a hollow portion, into which the proximal portion of the resin tube 10 is inserted.

[0073] As shown in Figs. 1 to 7, a second handle 32 may be connected to a proximal portion of the core wire 23. By moving the second handle 32 in the longitudinal direction x, the coil 22 connected to the core wire 23 via the distal tip 21 can be expanded or contracted. In detail, by moving the second handle 32 proximally from the first state shown in Fig. 1, the coil 22, particularly the pitch P2p of the proximal second section 228p, can be narrowed to a third state as shown in Fig. 3, and by moving the second handle 32 distally from the third state, the coil 22, particularly the pitch P2p of the proximal second section 228p can be returned to the first state.

[0074] The second handle 32 is preferably fixed radially outward of the core wire 23. The second handle 32 is preferably fixed to a proximal portion of the core wire 23. For example, as shown in Fig. 1, the second handle 32 may be configured to be a hollow cylinder having a hollow portion, into which the proximal portion of the resin tube 10 is inserted.

[0075] The first handle 31 and the second handle 32 can each be made of one or more members. The materials for making the first handle 31 and the second handle 32 are not particularly limited, but examples of the materials that can be used include synthetic resins such as polyolefin resins such as polypropylene (PP) and polyethylene (PE), polyester resins such as polyethylene terephthalate (PET), polycarbonate resins, ABS resins, and polyurethane resins.

[0076] The first handle 31 and the second handle 32 may have, for example, a hollow cylindrical shape or a hollow polygonal prism shape.

[0077] As shown in Fig. 1, the catheter system 100 may include a catheter 1 in which a first handle 31 is connected to a proximal portion of a resin tube 10 and a second handle 32 is connected to a proximal portion of a core wire 23, a high-frequency generator 51 connected to a distal tip 21, and a liquid supply device 52 that supplies liquid to a lumen 223 of the coil 22. In Figs. 2 to 7, the high-frequency generator 51, the liquid supply device 52, the conductive wire 41, the tubular member 42, and the switch 34 and the second operation unit 35 of the second handle 32 are omitted.

[0078] The high frequency generator 51 is a device capable of applying a high frequency electric field to the distal tip 21. The high frequency generator 51 may include a power supply circuit and a high frequency oscillation circuit.

[0079] The tip 21 and the high-frequency generator 51 may be connected via a conductive member such as a conductor 41. For example, one end of the conductor 41 may be connected to the tip 21, the conductor 41 may extend to the proximal side, and the other end of the conductor 41 may be connected to the high-frequency generator 51. In this case, the conductor 41 may be disposed inside the core wire 23 and inside the second handle 32, or may be disposed inside the lumen 223 of the coil 22 and inside the second handle 32. In this configuration, the tip 21 can be heated by applying a high-frequency electric field, making it easier to puncture the biological membrane. In addition, the tip 21 and the core wire 23 may be made of a conductive material, the core wire 23 may be connected to one end of the conductor 41, the conductor 41 may extend to the proximal side, and the other end of the conductor 41 may be connected to the high-frequency generator 51. In Figs. 1 to 7, an example is shown in which one end of the conductor 41 is connected to the core wire, and the other end of the conductor 41 is connected to the high-frequency generator 51.

[0080] The liquid supply device 52 refers to a device capable of supplying liquid to the lumen 223 of the coil 22. Examples of the liquid supply device 52 include a syringe and a pump. Examples of the liquid supplied to the lumen 223 of the coil 22 include saline, a contrast agent, or a mixture thereof.

[0081] The liquid supply device 52 is preferably connected to a proximal portion of the coil 22. The liquid supply device 52 may be directly connected to the coil 22 or indirectly connected via another member. As an example of the latter, the catheter system 100 may further include a tubular member 42 having an inner cavity 421 capable of communicating with the inner cavity 223 of the coil 22. For example, one end of the tubular member 42 may be connected to the liquid supply device 52, and the other end of the tubular member 42 may be connected to the coil 22. In addition, as shown in FIG. 1, when the second handle 32 has a hollow portion, in the first state, one end of the tubular member 42 may be connected to the second handle 32 so that the inner cavity 421 of the tubular member 42 communicates with the hollow portion of the second handle 32, and the second handle 32 and the coil 22 may be connected so that the hollow portion of the second handle 32 communicates with the inner cavity 223 of the coil 22.

[0082] In the first state, it is preferable that the liquid supply device 52 can supply liquid to the inner cavity 223 of the coil 22, and the high frequency generator 51 does not apply a high frequency electric field to the distal tip 21. With this configuration, the liquid sent from the liquid supply device 52 can be discharged from between the adjacent wires 220 in the second section 228.

[0083] On the other hand, when the coil 22 is contracted as in the third state, it is preferable that the high frequency generator 51 can apply a high frequency electric field to the distal tip 21, and the liquid supply device 52 does not supply liquid to the lumen 223 of the coil 22. This configuration increases the rigidity of the distal end of the guidewire member 20, making it easier for the distal tip 21 to pierce a biological membrane.

[0084] Either the first handle 31 or the second handle 32 may be provided with a switch for switching ON / OFF the connection between the high frequency generator 51 and the tip tip 21. In detail, it is preferable that the switch is controlled so that the connection between the high frequency generator 51 and the tip tip 21 is turned OFF in the first state, and the switch is controlled so that the connection between the high frequency generator 51 and the tip tip 21 is turned ON in the third state. FIG. 1 shows an example in which the switch 34 is provided on the second handle 32.

[0085] The application of the high frequency electric field by the high frequency generator 51 can be performed by operating the second operation unit 35, such as a button or lever, provided on the high frequency generator 51 or the second handle 32. Either the first handle 31 or the second handle 32 may further have a switch for switching the application of the high frequency electric field from the high frequency generator 51 ON / OFF. [Explanation of symbols]

[0086] 1: Catheter 10: Resin tube 10d: Distal end of the resin tube 10p: Proximal end of the resin tube 13: Inner cavity of resin tube 20: Guide wire member 21: Tip 21d: Distal end of tip 21p: Proximal end of tip 211: First end of the tip 212: Second end of the tip 22: Coil 22p: Proximal end of coil 2: Coil bore 220: Wire rod 23: Core wire 24:Protrusion 31: First handle 32: Second handle 51: High frequency generator 52:Liquid supply device

Claims

1. a resin tube having a longitudinal direction, a distal end and a proximal end in the longitudinal direction, and an inner lumen extending from the distal end to the proximal end; a coil wound with a wire having a first end and a second end located proximal to the first end, the first end of the wire being connected to the tip; and a core wire connected to the tip and disposed in an inner cavity of the coil, the guide wire member moving in the longitudinal direction relative to the resin tube, a catheter in which, after the guidewire member is moved distally so that the proximal end of the coil is positioned at the distal end relative to the plastic tube, in a first state in which no load other than gravity is applied to the coil, the coil has a first section disposed in the inner cavity of the plastic tube and a second section protruding from the distal end of the plastic tube, and when the length of the second section is divided in half in the longitudinal direction, the distal side is called the distal second section and the proximal side is called the proximal second section, the average pitch of the proximal second section is greater than the average pitch of the distal second section.

2. 2. The catheter of claim 1, wherein in the first state, the coil has a greater average pitch in the proximal second section than in the average pitch of the first section.

3. 3. The catheter of claim 1, wherein in the first state, the coil has an average pitch in the distal second section that is greater than the average pitch in the first section.

4. The catheter according to claim 1 or 2, wherein in the first state, the proximal second section is configured to be able to come into contact with a biological membrane.

5. 3. A catheter as described in claim 1 or 2, wherein, after the guide wire member is moved proximally so that the proximal end of the coil is positioned most proximal relative to the resin tube, in a second state in which no load other than gravity is applied to the coil, the distal end of the tip chip is at the same position as the distal end of the resin tube or at a position proximal to the distal end of the resin tube.

6. The catheter according to claim 1 or 2, wherein in the first state, adjacent wire members are in close contact with each other in the distal second section of the coil.

7. The catheter according to claim 1 or 2, wherein in the first state, there are gaps between adjacent wire members in the proximal second section of the coil.

8. The catheter of claim 1 or 2, wherein in the first state, the second section has a curved or bent shape.

9. 9. The catheter of claim 8, wherein in a third state, the guide wire member is moved distally so that the proximal end of the coil is positioned most distally relative to the resin tube, and then the core wire is moved proximally relative to the proximal end of the coil so that the distal end of the core wire is positioned most proximal, the second section has a straight shape.

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