Catheter tube, continuous catheter tube, and method for manufacturing a catheter tube

Abstract

The present invention provides a catheter tube, a continuous catheter tube, and a method for manufacturing a catheter tube that can improve suction performance compared to a case where the inclination of the inner circumferential surface of the inclined section connecting the large-diameter section and the small-diameter section is a constant tapered shape. [Solution] The catheter tube 1 comprises a large-diameter section 2, a small-diameter section 4 whose inner diameter is smaller than the inner diameter of the large-diameter section 2, and an inclined section 3 connecting the large-diameter section 2 and the small-diameter section 4 by an inclined inner circumferential surface 3a. The inclined inner circumferential surface 3a is mainly composed of a convex curve whose cross-sectional shape along the axial direction of the inner circumferential surface 3a passes outside the straight line Lt connecting the boundary P2 with the inner circumferential surface 2a of the large-diameter section and the boundary P1 with the inner circumferential surface 4a of the small-diameter section.

Description

[Technical Field]

[0001] The present invention relates to catheter tubes, and more particularly to catheter tubes in which the inner or outer circumferential surface of an inclined section connecting a large-diameter section and a small-diameter section is mainly composed of a convex curve, a continuous catheter tube, and a method for manufacturing a catheter tube. Regarding. [Background technology]

[0002] Conventionally, catheter tubes have been used as medical devices for inserting into biological tubular structures such as blood vessels to perform treatment, diagnosis, etc. (see, for example, Patent Document 1).

[0003] The catheter tube described in Patent Document 1 comprises a large-diameter section with a large inner and outer diameter at the proximal end to increase rigidity and ensure sufficient pushability while securing the injection characteristics of drugs and contrast agents, a small-diameter section that is narrower than the large-diameter section to improve access to peripheral blood vessels and followability to guide wires by making it flexible, and an inclined section connecting the large-diameter section and the small-diameter section with an inclined inner surface. The inclined section has a tapered shape on the outer and inner surfaces in a cross-section along the axial direction. Such a catheter tube is used, for example, to aspirate and collect or discharge objects to be aspirated from the body (blood, thrombus, body fluid, etc.). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2008-183226 [Overview of the project] [Problems that the invention aims to solve]

[0005] According to the catheter tube described in Patent Document 1, in the case of a tapered shape with a constant inclination on the inner peripheral surface of the inclined portion, since the cross-sectional area of the tube lumen increases linearly, there is a risk that the suction target cannot be sufficiently suctioned due to the suction resistance in the inclined portion when suctioning the suction target from inside the living body.

[0006] An object of the present invention is to provide a catheter tube, a continuous body of catheter tubes, and a method for manufacturing a catheter tube that can improve suction performance as compared with the case of a tapered shape with a constant inclination on the inner peripheral surface of the inclined portion connecting the large-diameter portion and the small-diameter portion.

Means for Solving the Problems

[0007] [1] Provided on the base end side A large-diameter portion, Located at the tip, a small-diameter portion having an inner diameter smaller than the inner diameter of the large-diameter portion, and an inclined portion connecting the large-diameter portion and the small-diameter portion with an inclined inner peripheral surface, the catheter tube comprising: the inner peripheral surface of the inclined portion has a convex curve passing outside a straight line connecting the boundary with the inner peripheral surface of the large-diameter portion and the boundary with the inner peripheral surface of the small-diameter portion in the cross-sectional shape along the axial direction of the inner peripheral surface It's fine formed into Ori , The tube lumen is formed so as to extend from the opening at the base end to the opening at the tip end. a catheter tube. <9000088> [3] When the shape is such that the cross-sectional shape is a tapered shape with a constant inclination, the degree of bulging of the convex curve at the intermediate position in the axial direction of the inclined portion is expressed by the following formula (1): A catheter tube as described in [1] above, wherein k is 0.2 or greater and 0.8 or less. k = (Dr - Dt) / (Dt - Db) ... (1) However, Dr is the inner diameter of the inner surface at the intermediate position, Db is the inner diameter of the inner surface of the small diameter portion, and Dt is the diameter at the intersection of the vertical line passing through the intermediate position and the straight line. 4 The convex curve has a slope of zero at the boundary with the inner peripheral surface of the large-diameter portion, and is a curve whose slope continuously or stepwise increases from the boundary with the inner peripheral surface of the large-diameter portion toward the boundary with the inner peripheral surface of the small-diameter portion, the catheter tube according to [1]. 5 The outer diameter size of the large-diameter portion is 2.0 Fr or more and 7.0 Fr or less, the 1 catheter tube according to the above. 6 ​​​The large diameter portion, the small diameter portion, and the inclined portion are formed from an inner layer made of resin and the outer surface of the inner layer From wire A reinforced layer is formed, and on the outside of the reinforced layer From resin Comprising an outer layer formed, The catheter tube according to [1], wherein the inner circumferential surfaces of the large diameter portion, the small diameter portion, and the inclined portion are the inner circumferential surfaces of the inner layer. [ 7 ] A method for manufacturing a catheter tube as described in [1] above, A core wire having a large diameter portion and a small diameter portion that are continuous at a predetermined interval, and the large diameter portion and the small diameter portion connected by an inclined portion having an inclined outer surface, wherein the outer surface of the inclined portion has a cross-sectional shape along the axial direction of the outer surface that is a convex curve passing outside the straight line connecting the boundary between the outer surface of the large diameter portion and the outer surface of the small diameter portion It's fine The core wire preparation process involves preparing the core wires that have already been assembled, A coating formation step involves coating the outer surface of the core wire with synthetic resin to form a coating, The continuous body on which the covering is formed is cut at predetermined positions of the large diameter portion and the small diameter portion of the core wire. With core material The cutting process for cutting out the tube, A core wire removal step of removing the core wire from the tube with the core wire, A method for manufacturing catheter tubes, including the tube itself. [8] A method for manufacturing the catheter tube described in [6] above, A core wire preparation step of preparing a core wire having a large diameter portion and a small diameter portion that are continuous at a predetermined interval, and the large diameter portion and the small diameter portion connected by an inclined portion having an inclined outer surface, wherein the outer surface of the inclined portion has a cross-sectional shape along the axial direction of the outer surface that is a convex curve passing outside the straight line connecting the boundary with the outer surface of the small diameter portion and the boundary with the outer surface of the large diameter portion, An inner layer forming step is performed by coating the outer surface of the core wire with resin to form an inner layer. A reinforcing layer formation step in which a reinforcing layer is formed on the outside of the inner layer using wire material, An outer layer forming step is performed by coating the outside of the reinforcing layer with resin to form an outer layer. A cutting step in which the continuous body on which the outer layer is formed is cut at predetermined positions of the large diameter portion and the small diameter portion of the core wire to cut out a tube with a core wire, A method for manufacturing a catheter tube, comprising a core wire removal step of removing the core wire from the tube with the core wire. [9] A core wire used in the method for manufacturing a catheter tube as described in [7] or [8] above.

[10] A continuum used in the method for manufacturing a catheter tube as described in [7] or [8] above.

[11] A tube with a core wire used in the method for manufacturing a catheter tube as described in [7] or [8] above. [Effects of the Invention]

[0008] According to the present invention, suction performance can be improved compared to the case where the inclination of the inner circumferential surface of the inclined portion connecting the large-diameter portion and the small-diameter portion is a constant tapered shape. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows a schematic configuration of a catheter tube according to the first embodiment of the present invention, where (a) is a longitudinal cross-sectional view and (b) is an enlarged view of part A in (a). [Figure 2] Figures 2(a) to 2(c) show the manufacturing process for catheter tubes in order of steps. [Figure 3] Figure 3 shows a schematic configuration of a continuous catheter tube according to a second embodiment of the present invention. [Figure 4] Figures 4(a) to 4(c) are schematic diagrams showing the process steps for manufacturing a catheter tube from a continuous tube of catheter tubes as shown in Figure 3. [Figure 5] Figure 5 is a longitudinal cross-sectional view showing the schematic configuration of a catheter tube according to a third embodiment of the present invention. [Figure 6] Figure 6 shows a schematic configuration of a continuous catheter tube according to a fourth embodiment of the present invention. [Figure 7] Figure 7 shows a schematic configuration of a catheter tube according to the fifth embodiment of the present invention, where (a) is a longitudinal cross-sectional view and (b) is an enlarged view of part A in (a). [Figure 8] Figure 8 shows the convex curve that constitutes the inner surface of the inclined portion of Example 1, along with Comparative Examples 1 and 2. [Figure 9] Figure 9 shows the convex curve that constitutes the inner surface of the inclined portion of Example 2, along with Comparative Examples 1 and 3. [Figure 10] Figure 10 shows the convex curve that constitutes the inner surface of the inclined portion of Example 3, along with Comparative Examples 1 and 4. [Figure 11] Figure 11 shows the convex curve that constitutes the inner surface of the inclined portion of Example 4, along with Comparative Examples 1 and 5. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In each figure, components having substantially the same function are denoted by the same reference numerals, and redundant descriptions thereof are omitted. In this specification, the side inserted into the body is referred to as the distal end, and the side operated by the surgeon is referred to as the proximal end.

[0011] [First Embodiment] Figure 1 shows a schematic configuration of a catheter tube according to the first embodiment of the present invention, where (a) is a longitudinal cross-sectional view and (b) is an enlarged view of part A in (a). As shown in Figure 1(a), this catheter tube 1A comprises a large-diameter section 2 having a predetermined inner diameter, a small-diameter section 4 having an inner diameter smaller than that of the large-diameter section 2, and an inclined section 3 connecting the large-diameter section 2 and the small-diameter section 4 with an inclined inner circumferential surface 3a. The catheter tube 1 is used, for example, to be inserted from the tip end into a lumen in the body (e.g., digestive tract, bile duct, pancreatic duct, blood vessel, ureter, etc.) for examination, treatment, etc.

[0012] The catheter tube 1A has a tube lumen 10 formed along the axial direction from a proximal opening 10a to a distal opening 10b. The tube lumen 10 is defined by a large-diameter inner surface 2a, an inclined inner surface 3a, and a small-diameter inner surface 4a. In Figure 1(a), 2b is the large-diameter outer surface, 3b is the inclined outer surface, and 4b is the small-diameter outer surface. The tube lumen 10 is used, for example, to pass a guide wire that guides the catheter tube 1A when it is inserted into a lumen in the body, or as a flow path for fluids such as drug solutions, contrast agents, and embolic materials. The catheter tube 1 is also used, for example, to aspirate and collect or discharge objects to be aspirated from the body (blood, thrombus, body fluids, etc.).

[0013] As shown in Figure 1(b), the inner circumferential surface 3a of the inclined section is mainly composed of a convex curve whose cross-sectional shape along the axial direction is outside the straight line connecting the boundary P2 with the inner circumferential surface 2a of the large diameter section and the boundary P1 with the inner circumferential surface 4a of the small diameter section, i.e., the tapered line Lt (on the opposite side of the central axis 10c of the tube lumen 10) (for example, when the convex curve occupies 80% or more of the axial length). The convex curve may be, for example, a curve in which the slope at the boundary P2 with the inner circumferential surface 2a of the large diameter section is zero, and the slope increases continuously or gradually from the boundary P2 towards the boundary P1 with the inner circumferential surface 4a of the small diameter section. By using such a curve, the cross-sectional area of ​​the tube lumen 10 of the inclined section increases more than if it were to increase linearly, so that when aspirating an object from inside the body, the suction resistance in the inclined section is reduced and the amount of object to be aspirated can be increased.

[0014] Next, the degree of bulging of the convex curve that constitutes the cross-sectional shape along the axial direction of the inner circumferential surface 3a of the inclined section is defined as follows. As shown in Figure 1(b), Da is the inner diameter of the large diameter section 2 (diameter of the inner circumferential surface 2a of the large diameter section), Db is the inner diameter of the small diameter section 4 (diameter of the inner circumferential surface 4a of the small diameter section), Dt is the diameter at the intersection P3 of the vertical line Lv and the tapered line Lt, passing through the axial intermediate position of the inclined section 3 (a position equidistant S in the axial direction from boundaries P1 and P2), and Dr is the inner diameter of the convex curve along the vertical line Lv. Ld is the amount of bulging of the convex curve from the tapered line Lt, and can be expressed as (Dr-Dt) / 2. Here, the "degree of bulging" is defined as the amount of bulging Ld = Small diameter inner peripheral surface 4a It is defined as the value obtained by dividing by the distance from ((Dt-Db) / 2) to intersection point P3 ((Dt-Db)). From the viewpoint of reducing suction resistance, the degree of bulging is preferably 0.1 or more or 0.2 or more as the lower limit, and 0.9 or less or 0.8 or less as the upper limit.

[0015] The material used to form the catheter tube 1A is not particularly limited, but examples include resin materials with elasticity such as flexibility that allows them to bend easily along the path of entry into the body, such as polyamide resins such as nylon, polyimide resins, polyolefin resins, polyester resins, polyurethane resins, fluororesins, etc., and elastomers thereof. These resin materials may be used individually or in combination of two or more. For example, a mixture of non-rubber materials such as nylon and polyurethane resin, a mixture of non-rubber and rubber materials such as nylon and polyimide elastomer, or a mixture of rubber materials such as polyamide elastomer and polyimide elastomer may be used. The material used to form the catheter tube 1A may be either a thermoplastic resin or a thermosetting resin, but a thermoplastic resin is preferred from the viewpoint of moldability and other factors.

[0016] As an example of the specific dimensions of catheter tube 1A, the large diameter section 2 has an inner diameter of 1.82 mm, an outer diameter of 2.00 mm, and an axial length of 1200 mm. The inclined section 3 has an axial length of 70 mm. The small diameter section 4 has an inner diameter of 1.66 mm, an outer diameter of 1.72 mm, and an axial length of 200 mm. The wall thickness of the large diameter section 2, inclined section 3, and small diameter section 4 is 0.05 mm. Note that the dimensions are not limited to the above and other sizes are also acceptable. For example, the inner diameter of the large diameter section 2 may be 1.72 to 1.92 mm and the inner diameter of the small diameter section 4 may be 1.56 to 1.76 mm, or the inner diameter of the large diameter section 2 may be 1.77 to 1.87 mm and the inner diameter of the small diameter section 4 may be 1.61 to 1.71 mm. The wall thickness may be 0.05 to 0.10 mm. The axial length of the inclined section 3 may be 50 to 80 mm. The outer diameter of the large-diameter section 2 may be 2.0 Fr (approximately 0.7 mm) or more, and 7.0 Fr (approximately 2.3 mm) or less. For example, a catheter tube 1 with an outer diameter of 6.0 Fr (2.0 mm) for the large-diameter section 2 may be used to aspirate and collect or discharge substances from within the body (blood, thrombus, body fluids, etc.). Alternatively, a catheter tube 1A with an outer diameter of 3.0 Fr (1.0 mm) for the large-diameter section 2 may be used when injecting fluids such as drug solutions, contrast agents, or embolic materials into the neurovascular or peripheral vascular system.

[0017] (Manufacturing method according to the first embodiment) Next, an example of a method for manufacturing catheter tube 1A will be described with reference to Figure 2. Figures 2(a) to (c) show the manufacturing process of catheter tube 1A in order of steps.

[0018] (1) Core wire preparation process As shown in Figure 2(a), a core wire preparation process is performed to manufacture a core wire 5 having an outer surface corresponding to the inner surface of the catheter tube 1A, that is, a core wire 5 having a large diameter section 51, an inclined section 52, and a small diameter section 53, each having an outer surface corresponding to the inner surface 2a of the large diameter section, the inner surface 3a of the inclined section, and the inner surface 4a of the small diameter section, respectively.

[0019] The core wire 5 can be manufactured, for example, by machining (cutting, polishing, grinding, forging such as swaging, drawing and stretching using a split die, etc.) or chemical processing (wet etching, etc.) of the material, through a process of reducing the diameter so that a large-diameter portion 51 having a predetermined outer diameter, a small-diameter portion 53 having a smaller outer diameter than the large-diameter portion 51, and an inclined portion 52 connecting the large-diameter portion 51 and the small-diameter portion 53 each have a predetermined length.

[0020] Examples of materials for the core wire 5 include metals with excellent ductility such as copper wire and stainless steel soft wire. The core wire 5 is not limited to a circular shape, but can be any shape such as an ellipse, semicircle, or polygon. Furthermore, the surface of the core wire 5 may be plated with silver or the like.

[0021] (2) Covering formation process Next, as shown in Figure 2(b), a coating formation step is performed to form a coating 6 on the outer surface of the core wire 5.

[0022] The coating 6 can be made of synthetic resin (mainly thermoplastic resin), such as polyamide resin, polyimide resin, polyolefin resin, polyester resin, polyurethane resin, fluororesin, etc., or elastomers thereof. These resin materials may be used individually or in combination of two or more. For example, a mixture of non-rubber materials such as nylon and polyurethane resin, a mixture of non-rubber and rubber materials such as nylon and polyimide elastomer, or a mixture of rubber materials such as polyamide elastomer and polyimide elastomer may be used. The coating 6 may be a laminated structure of two or more layers, not just one layer. Furthermore, a coating method may be used in which the rigidity of the tube changes continuously or stepwise from the handle side to the tip side.

[0023] The coating formation process is carried out, for example, by extrusion molding of a synthetic resin (mainly a thermoplastic resin). Alternatively, dip molding may be performed, in which the core wire 5 is immersed in a coating solution in which a synthetic resin (mainly a thermoplastic resin) is dissolved in a predetermined solvent at a predetermined concentration, and then pulled out at a predetermined speed to coat the outer circumference of the core wire 5 with synthetic resin and form a coating 6 of approximately the same thickness. In this dip molding, fluororesins such as PTFE and PFA are preferable among the thermoplastic resins. Alternatively, a method of coating and sintering PTFE dispersion or the like may also be used.

[0024] (3) Core wire removal process Next, as shown in Figure 2(c), a core wire removal process is performed to remove the core wire 5 embedded in the insulation 6.

[0025] The core wire removal process involves cutting or removing the ends of the core wire 5 and the covering 6 to a predetermined length (for example, 20 mm) to expose the core wire 5, then fixing it to a stretching machine to stretch the entire core wire 5, and finally pulling out the core wire 5 from the large diameter portion 51 side in the direction of the large diameter portion 51 (in the direction of the arrow in Figure 2(c)).

[0026] (Effects of the first embodiment) The catheter tube 1A according to this embodiment provides the following effects. (a) By mainly constructing the inner circumferential surface 3a of the inclined section 3 with a convex curve, the cross-sectional area of ​​the tube lumen 10 of the inclined section 3 increases more significantly than if it increased linearly, and the suction resistance in the inclined section is reduced when aspirating the object to be aspirated from inside the body. As a result, the amount of the object to be aspirated can be increased. (b) When using catheter tube 1A to inject fluids such as drugs or contrast agents into the body, pressure fluctuations during fluid injection can be reduced. In other words, fluids can be injected at low pressure. Therefore, even fluids with high viscosity can be injected.

[0027] [Second Embodiment] Figure 3 shows a schematic configuration of a continuous catheter tube according to a second embodiment of the present invention. The continuous catheter tube 100A allows for the production of multiple catheter tubes 1A according to the first embodiment, and comprises a core wire 5 in which a large diameter portion 51 and a small diameter portion 53 are continuous at predetermined intervals and the large diameter portion 51 and the small diameter portion 53 are connected by an inclined portion 52, and a covering 6 obtained by coating the outer surface of the core wire 5 with a synthetic resin (mainly a thermoplastic resin).

[0028] The outer surface of the inclined portion 52 of the core wire 5 is mainly composed of a convex curve whose cross-sectional shape along the axial direction of the outer surface passes outside (on the opposite side of the central axis of the core wire 5) the straight line connecting the boundary with the outer surface of the large diameter portion 51 and the boundary with the outer surface of the small diameter portion 53 (for example, when the convex curve occupies 80% or more of the axial length).

[0029] (Manufacturing method according to the second embodiment) Figures 4(a) to 4(c) are schematic diagrams showing the process sequence for manufacturing a catheter tube from the continuous catheter tube 100A shown in Figure 3. First, as shown in Figure 4(a), a core wire preparation process is performed to manufacture a core wire 5 in which a large diameter section 51 and a small diameter section 53 are continuous at a predetermined interval, and the large diameter section 51 and the small diameter section 53 are connected by an inclined section 52. Note that the material and processing method of the core wire 5 are the same as in the first embodiment, so their explanation is omitted.

[0030] Next, as shown in Figure 4(b), a coating formation step is performed to form a coating 6 on the outer surface of the core wire 5. The material of the coating 6 and the coating formation step are the same as in the first embodiment, so their explanation will be omitted.

[0031] Next, as shown in Figure 4(c), a cutting process is performed to cut multiple catheter tubes by cutting the large-diameter portion 51 and the small-diameter portion 53 of the core wire 5 at predetermined cutting positions (for example, positions 7A and 7B). Alternatively, the cutting may be done at the position of the cutting position 7C in the longitudinal center of the large-diameter portion 51, and at the position of the cutting position 7D in the longitudinal center of the small-diameter portion 53. This allows for the production of catheter tubes 1A to the left and right of a single cutting position 7C. The cutting method can be cutting with a cutting blade, for example, by a shearing machine, but any cutting method that cuts the core wire 5 and the covering 6 is acceptable.

[0032] After cutting, a core wire removal process is performed to remove the core wire 5 embedded in the covering 6, as shown in Figure 2(c). Multiple catheter tubes 1A are manufactured in this manner.

[0033] (Effects of the second embodiment) According to the continuous catheter tube 100A of this embodiment, multiple catheter tubes 1A can be taken from a single continuous catheter tube 100, thus improving productivity compared to manufacturing catheter tubes 1A one by one.

[0034] [Third Embodiment] Figure 5 is a longitudinal cross-sectional view showing the schematic configuration of a catheter tube according to the third embodiment of the present invention. In this embodiment, the catheter tube 1B has the catheter tube 1A of the first embodiment as an inner layer 11A, a reinforcing layer 11B formed on the outside of the inner layer 11A, and an outer layer 11C formed on the outside of the reinforcing layer 11B. Since the outer layer 11C reflects the shape of the inner layer 11A, the catheter tube 1B comprises a large-diameter section 12 having a predetermined inner diameter, a small-diameter section 14 with an inner diameter smaller than the large-diameter section 12, and an inclined section 13 connecting the large-diameter section 12 and the small-diameter section 14 at the inclined inner circumferential surface of the inclined section.

[0035] The reinforcing layer 11B may be composed of a coil formed by spirally winding a linear member, or a braided body formed by weaving a linear member. As the linear member, strands made of metal (e.g., stainless steel, tungsten steel, titanium-nickel alloy (Ti-Ni), etc.) or non-metal (e.g., fluorocarbon fiber, aramid fiber, polyphenylene sulfide fiber, polyarylate fiber, etc.) can be used. Note that the reinforcing layer 11B may not be formed along the entire length of the inner layer 11A, but only on a part of the inner layer 11A (e.g., the large diameter portion 2).

[0036] The outer layer 11C can be made of thermoplastic resins, such as polyamide resins, polyimide resins, polyolefin resins, polyester resins, polyurethane resins, fluororesins, etc., or elastomers thereof. These resin materials may be used individually or in combination of two or more. For example, a mixture of non-rubber materials such as nylon and polyurethane resin, a mixture of non-rubber and rubber materials such as nylon and polyimide elastomer, or a mixture of rubber materials such as polyamide elastomer and polyimide elastomer may be used. The outer layer 11C may also be made by mixing a radiopaque substance with the thermoplastic resin. This makes it easier to confirm the position of the catheter tube 1B under X-ray fluoroscopy, etc. Furthermore, an outermost layer made of thermoplastic resin, etc., may be formed on a part of the outer layer 11C (for example, the large diameter portion 12). This increases the rigidity of the large diameter portion 12 and improves the pushability.

[0037] (Manufacturing method according to the third embodiment) Next, an example of a method for manufacturing the catheter tube 1B will be described. Similar to the first embodiment, a core wire preparation step is performed to manufacture the core wire 5, and a coating formation step is performed to form a coating 6 on the outer surface of the core wire 5.

[0038] Next, a reinforcing layer forming step is performed to form a reinforcing layer 11B on the outside of the covering 6. The reinforcing layer forming step is a step of continuously braiding linear members made of metal or nonmetal on the covering 6 at a predetermined grid distance. The braiding may be done by winding the wires while changing the winding direction, such as horizontal winding in the same direction, or right-handed winding, left-handed winding, etc., and there are no particular limitations on the winding pitch or grid distance.

[0039] Next, an outer layer forming step is performed to form an outer layer 11C on the outside of the reinforcing layer 11B. The outer layer coating forming step is a process in which, for example, a thermoplastic resin is used and the outside of the reinforcing layer 11B is coated and integrally extruded using an extrusion molding machine at a predetermined molding temperature and predetermined take-up speed.

[0040] Next, a core wire removal process is performed to remove the core wire 5 embedded in the inner layer 11A's covering 6. The core wire removal process is performed in the same manner as described in the first embodiment.

[0041] (Effects of the third embodiment) According to the catheter tube 1B of this embodiment, the reinforcing layer 11B reinforces the tube along its longitudinal direction, thereby improving its indentation resistance and kink resistance.

[0042] [Fourth Embodiment] Figure 6 shows a schematic configuration of a continuous catheter tube according to the fourth embodiment of the present invention. The continuous catheter tube 100B allows for the production of multiple catheter tubes 1B according to the third embodiment, and comprises a core wire 5 in which a large diameter portion 51 and a small diameter portion 53 are continuous at a predetermined interval and the large diameter portion 51 and the small diameter portion 53 are connected by an inclined portion 52, a covering 6 which constitutes an inner layer 101A obtained by coating the outer surface of the core wire 5 with synthetic resin (mainly thermoplastic resin), a reinforcing layer 101B formed on the outside of the covering 6, and an outer layer 101C formed on the outside of the reinforcing layer 101B.

[0043] The reinforcing layer 101B may be composed of a coil formed by spirally winding a linear member, or a braided body formed by weaving a linear member, similar to the reinforcing layer 11B in the third embodiment.

[0044] The outer layer 101C can be made of a thermoplastic resin, similar to the outer layer 11C in the third embodiment.

[0045] (Effects of the fourth embodiment) According to the continuous catheter tube 100B of this embodiment, similar to the second embodiment, multiple catheter tubes 1B can be obtained from a single continuous catheter tube 100B by cutting at the positions of the cutting sections 7A to 7D, thus improving productivity compared to manufacturing catheter tubes 1B one by one.

[0046] [Fifth Embodiment] Figure 7 shows a schematic configuration of a catheter tube according to the fifth embodiment of the present invention, where (a) is a longitudinal cross-sectional view and (b) is an enlarged view of part A in (a). As shown in Figure 7(a), this catheter tube 1A comprises a large-diameter section 2 having a predetermined outer diameter, a small-diameter section 4 having an outer diameter smaller than that of the large-diameter section 2, and an inclined section 3 connecting the large-diameter section 2 and the small-diameter section 4 by an inclined outer surface 3b. The catheter tube 1A is used, for example, to be inserted from the tip end into a lumen in the body (e.g., digestive tract, bile duct, pancreatic duct, blood vessel, ureter, etc.) for examination, treatment, etc.

[0047] The catheter tube 1A has a tube lumen 10 formed along the axial direction from a proximal opening 10a to a distal opening 10b. The tube lumen 10 is defined by a large-diameter inner surface 2a, an inclined inner surface 3a, and a small-diameter inner surface 4a. In Figure 7(a), 2b is the large-diameter outer surface, 3b is the inclined outer surface, and 4b is the small-diameter outer surface. The tube lumen 10 is used, for example, to pass a guide wire that guides the catheter tube 1A when it is inserted into a lumen in the body, or as a flow path for fluids such as drug solutions, contrast agents, and embolic materials. The catheter tube 1A is also used, for example, to aspirate and collect or discharge objects to be aspirated from the body (blood, thrombi, body fluids, etc.).

[0048] As shown in Figure 7(b), the outer surface 3b of the inclined portion has a cross-sectional shape along the axial direction that is mainly composed of a convex curve passing outside the straight line connecting the boundary P2 with the outer surface 2b of the large diameter portion and the boundary P1 with the outer surface 4b of the small diameter portion, i.e., the tapered line Lt (on the opposite side of the central axis 10c of the tube lumen 10) (for example, when the convex curve occupies 80% or more of the axial length). The convex curve may be, for example, a curve in which the slope at the boundary P2 with the outer surface 2b of the large diameter portion is zero, and the slope increases continuously or gradually from the boundary P2 towards the boundary P1 with the outer surface 4b of the small diameter portion. By using such a curve, the torsional rigidity of the inclined portion 3 is increased compared to when the outer surface of the inclined portion is tapered, and the torqueability is increased.

[0049] Next, the degree of bulging of the convex curve that constitutes the cross-sectional shape along the axial direction of the outer surface 3b of the inclined section is defined as follows. As shown in Figure 7(b), Da is the outer diameter of the large diameter section 2 (diameter of the outer surface 2b of the large diameter section), Db is the outer diameter of the small diameter section 4 (diameter of the outer surface 4b of the small diameter section), Dt is the diameter at the intersection P3 of the vertical line Lv and the tapered line Lt, passing through the axial intermediate position of the inclined section 3 (a position equidistant S in the axial direction from boundaries P1 and P2), and Dr is the outer diameter of the convex curve at the vertical line Lv. Ld is the amount of bulging of the convex curve from the tapered line Lt and can be expressed as (Dr-Dt) / 2. Here, the "degree of bulging" is the amount of bulging Ld Small diameter part outer peripheral surface 4b It is defined as the value obtained by dividing by the distance from ((Dt-Db) / 2) to intersection point P3 ((Dt-Db)). From the viewpoint of reducing suction resistance, the degree of bulging is preferably 0.1 or more or 0.2 or more as the lower limit, and 0.9 or less or 0.8 or less as the upper limit.

[0050] The material used to form the catheter tube 1A is not particularly limited, but examples include resin materials with elasticity such as flexibility that allows them to bend easily along the path of entry into the body, such as polyamide resins, polyimide resins, polyolefin resins (such as low-density polyethylene), and fluororesins. The material used to form the catheter tube 1A may be either a thermoplastic resin or a thermosetting resin, but a thermoplastic resin is preferred from the viewpoint of moldability and other factors.

[0051] As an example of the specific dimensions of catheter tube 1A, the large diameter section 2 has an inner diameter of 1.34 mm, an outer diameter of 1.40 mm, and an axial length of 1200 mm. The inclined section 3 has an axial length of 70 mm. The small diameter section 4 has an inner diameter of 0.99 mm, an outer diameter of 1.05 mm, and an axial length of 200 mm. The wall thickness of the large diameter section 2, inclined section 3, and small diameter section 4 is 0.06 mm. Note that the dimensions are not limited to the above and other sizes are also acceptable. For example, the outer diameter of the large diameter section 2 may be 1.30 to 1.50 mm and the outer diameter of the small diameter section 4 may be 0.95 to 1.15 mm, or the outer diameter of the large diameter section 2 may be 1.35 to 1.45 mm and the outer diameter of the small diameter section 4 may be 1.00 to 1.10 mm. The wall thickness may be 0.05 to 0.10 mm. The axial length of the inclined section 3 may be 50 to 80 mm. The outer diameter of the large-diameter section 2 may be 3.0 Fr (1.0 mm) or more, and 5.0 Fr (approximately 1.7 mm) or less. For example, a catheter tube 1A with an outer diameter of 3.0 Fr (1.0 mm) of the large-diameter section 2 may be used when inserting it into the neurovascular or peripheral vascular system while transmitting torque force from the proximal end to the tip, following the guidewire.

[0052] The method for manufacturing the catheter tube 1A in the fifth embodiment is the same as in the first embodiment, so its description will be omitted.

[0053] (Effects of the fifth embodiment) According to the catheter tube 1A of this embodiment, by mainly configuring the outer circumferential surface 3b of the inclined portion 3 with a convex curve, the same effects as in the first embodiment, in which the inner circumferential surface 3a of the inclined portion 3 is mainly configured with a convex curve, can be obtained. Furthermore, according to this embodiment, compared to the case in which the inner circumferential surface 3a and the outer circumferential surface 3b of the inclined portion are mainly configured with concave curves, the cross-sectional area of ​​the inclined portion 3 can be increased, thereby improving rigidity. For this reason, if this embodiment is used in a guiding catheter or the like, backup properties (the property that the tip of the catheter is less likely to come out of the target site when a therapeutic device or the like is used in the guiding catheter) can also be expected.

[0054] Furthermore, the fifth embodiment may be a continuous catheter tube, similar to the second embodiment. Moreover, the fifth embodiment may be a catheter tube having a reinforcing layer, similar to the third embodiment. Furthermore, the fifth embodiment may be a continuous catheter tube having a reinforcing layer, similar to the fourth embodiment.

[0055] (Variation 1) The catheter tube 1A is not limited to a single-layer structure, but may also have a structure comprising multiple resin layers (for example, an inner resin layer and an outer resin layer).

[0056] (Modification 2) Each step in the process from the continuous catheter tube to the manufacture of the catheter tube may be distributed among multiple companies. For example, Company A may manufacture a continuous catheter tube with a coating (inner layer) formed on the outer circumference of the core wire, cut this continuous tube at a predetermined position to manufacture a catheter tube with a core wire, and Company B may form a reinforcing layer and an outer layer on the outer circumference of the core tube manufactured by Company A, and pull out the core wire to manufacture a catheter tube. Alternatively, Company A may manufacture a continuous catheter tube with a coating (inner layer) formed on the outer circumference of the core wire and a reinforcing layer formed on the inner layer, cut this continuous tube at a predetermined position to manufacture a catheter tube with a core wire, and Company B may form an outer layer on the outer circumference of the core tube manufactured by Company A, and pull out the core wire to manufacture a catheter tube.

[0057] (Variation 3) By coating the catheter tube with resins of gradually different flexibility from the large diameter section to the small diameter section, the tip end may be made more flexible than the proximal end. [Examples]

[0058] Next, an embodiment relating to the first embodiment will be described.

[0059] (Example 1) Figure 8 shows the convex curve that constitutes the inner circumferential surface 3a of the inclined section of Example 1, along with Comparative Examples 1 and 2. Comparative Example 1 shows the case where the inner circumferential surface of the inclined section is tapered, and Comparative Example 2 shows the case where the inner circumferential surface of the inclined section is constructed with a concave curve. The concave curve is a curve that passes inside the straight line Lt connecting the boundary P2 with the inner circumferential surface 2a of the large diameter section and the boundary P1 with the inner circumferential surface 4a of the small diameter section (on the side of the central axis 10c of the tube lumen 10) (the same applies to Figures 9 to 11). In the same figure, the horizontal axis shows the length (mm) in the axial direction (x direction) from the boundary P1, and the vertical axis shows the inner diameter (mm) in the radial direction (y direction) of the inner circumferential surface of the inclined section (the same applies to Figures 9 to 11). Also, in the same figure, the solid line shows the measured value of the core wire that was actually manufactured, and the dashed line shows the approximate value obtained by approximating the measured value using a polynomial (the same applies to Figures 9 to 11).

[0060] The approximate formula for the convex curve of Example 1 can be expressed as follows. y = 3×10 -8 x 4 - 3×10 -6 x 3 + 8×10 -5 x 2 - 0.0004x + 0.83

[0061] The straight line of Comparative Example 1 can be expressed as follows. y = 0.0021x + 0.83

[0062] The approximate formula for the concave curve of Comparative Example 2 can be expressed as follows. y = - 3×10 -8 x 4 + 6×10 -6 x 3 - 0.0004x 2 + 0.0123x + 0.83

[0063] (Example 2) FIG. 9 is a diagram showing the convex curve constituting the inner peripheral surface 3a of the inclined portion of Example 2 together with Comparative Example 1 and Comparative Example 3. Comparative Example 1 shows the case where the inner peripheral surface of the inclined portion is tapered, and Comparative Example 3 shows the case where the inner peripheral surface of the inclined portion is formed of a concave curved surface.

[0064] The approximate formula for the convex curve of Example 2 can be expressed as follows. y = 4×10 -8 x 4 - 5×10 -6 x 3 + 0.0002x 2 - 0.0012x + 0.83

[0065] The approximate formula for the concave curve of Comparative Example 3 can be expressed as follows. y = - 4×10 -8 x 4 + 7×10 -6 x 3 - 0.0004x 2 + 0.0108x + 0.83

[0066] (Example 3) Figure 10 shows the convex curve that constitutes the inner circumferential surface 3a of the inclined portion in Example 3, along with Comparative Examples 1 and 4. Comparative Example 1 shows the case where the inner circumferential surface of the inclined portion is tapered, and Comparative Example 4 shows the case where the inner circumferential surface of the inclined portion is composed of a concave curve.

[0067] The approximate formula for the convex curve in Example 3 can be expressed as follows: y = 3 × 10 -8 x 4 -3 × 10 -6 x 3 +0.0001x 2 +0.0001x+0.83

[0068] The approximate formula for the concave curve in Comparative Example 4 can be expressed as follows: y = -3 × 10 -8 x 4 +5 × 10 -6 x 3 -0.0003x 2 +0.0095x+0.83

[0069] (Example 4) Figure 11 shows the convex curve that constitutes the inner circumferential surface 3a of the inclined portion in Example 4, along with Comparative Examples 1 and 5. Comparative Example 1 shows the case where the inner circumferential surface of the inclined portion is tapered, and Comparative Example 5 shows the case where the inner circumferential surface of the inclined portion is composed of a concave curve.

[0070] The approximate formula for the convex curve in Example 4 can be expressed as follows: y = 4 × 10 -9 x 4 -1 × 10 -17 x 3 -1 × 10 -5 x 2 +0.0013x+0.83

[0071] The approximate formula for the concave curve in Comparative Example 5 can be expressed as follows: y = -3 × 10 -8 x 4 +5 × 10 -6 x 3 -0.0003x 2 +0.0078x+0.83

[0072] (Suction volume comparison experiment 1) Tables 1 and 2 show the results of comparative experiment 1 on the amount of suction for Examples 1 to 4 and Comparative Examples 1 to 5 described above. Since it is difficult to quantify the amount of suction when thrombi are used as the target of suction, the amount of physiological saline suctioned was evaluated. Specifically, a catheter hub was attached to the proximal end of the catheter tube used in the experiment (large diameter section length: 1185 mm, large diameter section inner diameter: 1.82 mm, inclined section length: 100 mm, small diameter section length: 200 mm, small diameter section inner diameter: 1.66 mm), the tip of the catheter tube was immersed in a beaker containing physiological saline, a syringe with a stopcock was connected to the catheter hub, the syringe was made negatively pressurized with the stopcock closed, and the amount of physiological saline suctioned was measured after 10 seconds had passed since opening the stopcock. In Tables 1 and 2, the evaluation was as follows: △ for the amount of suction of Comparative Example 1, ○ for 10% or more than Comparative Example 1, and × for 10% or more than less than Comparative Example 1.

[0073] (Comparative experiment on pressure fluctuations during fluid injection 2) Tables 1 and 2 show the results of comparative experiment 2 on pressure fluctuations during fluid injection for Examples 1 to 4 and Comparative Examples 1 to 5 described above. When positive pressure is applied during drug administration, the internal pressure of the catheter tube gradually increases, reducing operability. Therefore, the pressure increase trend was evaluated using a pressure gauge. Specifically, a catheter hub was incorporated into the proximal end of the experimental catheter tube (large diameter section length: 1185 mm, large diameter section inner diameter: 1.82 mm, inclined section length: 100 mm, small diameter section length: 200 mm, small diameter section inner diameter: 1.66 mm), a syringe filled with a glycerin aqueous solution with a viscosity of 10 cP was connected to the catheter hub, and the pressure when the syringe was pushed was measured using a pressure gauge. In Tables 1 and 2, the evaluation was as follows: △ for the suction volume and pressure of Comparative Example 1, ○ for cases that were 10% or more smaller than Comparative Example 1, and × for cases that were 10% or more larger than Comparative Example 1.

[0074] [Table 1]

[0075] [Table 2]

[0076] (Evaluation results) From the results of Comparative Experiment 1, as shown in Tables 1 and 2, it was found that by mainly composing the shape of the inclined inner surface of Examples 1 to 4 with a convex curve, the suction volume could be increased compared to Comparative Example 1, and even more so than Comparative Examples 2 to 5.

[0077] From the results of Comparative Experiment 2, as shown in Tables 1 and 2, it was found that Examples 1 to 4 could reduce the pressure more than Comparative Example 1 and even more than Comparative Examples 2 to 5 by mainly composing the shape of the inclined inner circumferential surface with a convex curve.

[0078] Although embodiments of the present invention have been described above, the embodiments of the present invention are not limited to those described above, and various modifications and implementations are possible.

[0079] Furthermore, some of the components of the above embodiment may be omitted or modified. Also, steps may be added, deleted, modified, or replaced in the method of the above embodiment. [Explanation of Symbols]

[0080] 1A, 1B…Catheter tube, 2, 12…Large diameter section, 2a…Inner surface of large diameter section, 2b…Outer surface of large diameter section, 3, 13…Inclined section, 3a…Inner surface of inclined section, 3b…Outer surface of inclined section, 4, 14…Small diameter section, 4a…Inner surface of small diameter section, 4b…Outer surface of small diameter section, 5…Core wire, 6…Sheathing, 7A, 7B…Cut section, 10…Tube lumen, 10a…Proximal end opening, 10b…Tip opening, 10c…Central axis, 51…Large diameter section, 52…Inclined section, 53…Small diameter section, 100A, 100B…Continuous catheter tube, Lt…Tapered line, Lv…Vertical line, P1, P2…Boundary, P3…Intersection

Claims

1. A catheter tube comprising: a large-diameter portion provided on the proximal end side; a small-diameter portion provided on the tip side, having an inner diameter smaller than the inner diameter of the large-diameter portion; and an inclined portion connecting the large-diameter portion and the small-diameter portion with an inclined inner circumferential surface, The inner circumferential surface of the inclined portion has a cross-sectional shape along the axial direction of the inner circumferential surface that is a convex curve passing outside the straight line connecting the boundary between the inner circumferential surface of the large diameter portion and the boundary between the inner circumferential surface of the small diameter portion. The tube lumen is formed so as to extend from the opening at the base end to the opening at the tip end. Catheter tube.

2. The inner circumferential surface of the inclined portion has a shape such that the suction resistance when a fluid from within a living body is drawn in from the opening on the tip side is smaller than when the cross-sectional shape of the inclined portion is tapered with a constant incline. A catheter tube according to claim 1.

3. When the shape is such that the cross-sectional shape is a tapered shape with a constant inclination, the degree of bulging of the convex curve at the intermediate position in the axial direction of the inclined portion k is expressed by the following formula (1): The catheter tube according to claim 1, wherein k is 0.2 or more and 0.8 or less. k=(Dr-Dt) / (Dt-Db)...(1) However, Dr is the inner diameter of the inner circumferential surface at the intermediate position, Db is the inner diameter of the inner circumferential surface of the small diameter portion, and Dt is the diameter at the intersection of the vertical line passing through the intermediate position and the straight line.

4. The aforementioned convex curve has zero slope at the boundary with the inner surface of the large diameter portion, and the slope increases continuously or gradually from the boundary with the inner surface of the large diameter portion towards the boundary with the inner surface of the small diameter portion. A catheter tube according to claim 1.

5. The outer diameter size of the large diameter portion is 2.0 Fr or more and 7.0 Fr or less. A catheter tube according to claim 1.

6. The large-diameter portion, the small-diameter portion, and the inclined portion each comprise an inner layer formed from resin, a reinforcing layer formed from wire on the outside of the inner layer, and an outer layer formed from resin on the outside of the reinforcing layer. The inner circumferential surfaces of the large diameter portion, the small diameter portion, and the inclined portion are the inner circumferential surfaces of the inner layer. A catheter tube according to claim 1.

7. A method for manufacturing a catheter tube according to Claim 1, A core wire preparation step of preparing a core wire having a large diameter portion and a small diameter portion that are continuous at a predetermined interval, and the large diameter portion and the small diameter portion connected by an inclined portion having an inclined outer surface, wherein the outer surface of the inclined portion has a cross-sectional shape along the axial direction of the outer surface that is a convex curve passing outside the straight line connecting the boundary with the outer surface of the large diameter portion and the boundary with the outer surface of the small diameter portion, A coating formation step involves coating the outer surface of the core wire with synthetic resin to form a coating, A cutting step in which the continuous body on which the covering is formed is cut at predetermined positions of the large-diameter and small-diameter portions of the core wire to cut out a tube with the core wire, A core wire removal step of removing the core wire from the tube with the core wire, A method for manufacturing catheter tubes, including the tube itself.

8. A method for manufacturing a catheter tube according to claim 6, A core wire preparation step of preparing a core wire having a large diameter portion and a small diameter portion that are continuous at a predetermined interval, and the large diameter portion and the small diameter portion connected by an inclined portion having an inclined outer surface, wherein the outer surface of the inclined portion has a cross-sectional shape along the axial direction of the outer surface that is a convex curve passing outside the straight line connecting the boundary with the outer surface of the small diameter portion and the boundary with the outer surface of the large diameter portion, An inner layer forming step is performed by coating the outer surface of the core wire with resin to form an inner layer. A reinforcing layer formation step in which a reinforcing layer is formed on the outside of the inner layer using wire material, An outer layer forming step is performed by coating the outside of the reinforcing layer with resin to form an outer layer. A cutting step in which the continuous body on which the outer layer is formed is cut at predetermined positions of the large diameter portion and the small diameter portion of the core wire to cut out a tube with a core wire, A core wire removal step of removing the core wire from the tube with the core wire, A method for manufacturing catheter tubes, including the tube itself.

9. A core wire used in the method for manufacturing a catheter tube according to claim 7 or 8.

10. A continuous body used in the method for manufacturing a catheter tube according to claim 7 or 8.

11. A tube with a core wire used in the method for manufacturing a catheter tube according to claim 7 or 8.

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