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, which allow for a longer fluid injection distance from the tip opening compared to a case where the inner circumferential surface of the inclined section connecting the large-diameter section and the small-diameter section has a tapered shape with a constant incline. [Solution] The catheter tube 1A 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 concave curve whose cross-sectional shape along the axial direction of the inner circumferential surface passes inside the straight line connecting the boundary with the inner circumferential surface 4a of the small diameter section and the boundary with the inner circumferential surface 2a of the large diameter section.

Description

[Technical Field]

[0001] The present invention relates to catheter tubes, and more particularly to catheter tubes in which the inner circumferential surface of the inclined portion connecting the large-diameter portion and the small-diameter portion is mainly composed of a concave curve, a continuous catheter tube, and a method for manufacturing a catheter tube. [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 a sloping section connecting the large-diameter section and the small-diameter section with a sloping inner surface. The sloping section has a tapered shape on the outer and inner surfaces in a cross-section along the axial direction. When injecting fluids such as drugs and contrast agents into the body using such a catheter tube, the proximal end of the large-diameter section is usually connected to a fluid source, and the fluid is introduced into the catheter tube from there. The fluid introduced into the catheter tube flows through the lumen of the sloping section due to the pressure applied at the proximal end, and then through the lumen of the small-diameter section before being injected into the body through the tip opening. [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, since the inclination of the inner peripheral surface of the inclined portion is a constant tapered shape, the inclination of the inner peripheral surface becomes a resistance when pumping a fluid such as a drug or a contrast agent from the inclined portion to the small-diameter portion, and there is a risk that the fluid cannot be pumped to the target location.

[0006] An object of the present invention is to provide a catheter tube, a continuum of catheter tubes, and a method for manufacturing a catheter tube that can increase the injection distance of fluid from the tip opening as compared with the case where the inclination of the inner peripheral surface of the inclined portion connecting the large-diameter portion and the small-diameter portion is a constant tapered shape.

Means for Solving the Problems

[0007] [1] A catheter tube comprising a large-diameter portion, 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, wherein the inner peripheral surface of the inclined portion has a concave curve whose cross-sectional shape along the axial direction of the inner peripheral surface passes inside a straight line connecting the boundary with the inner peripheral surface of the small-diameter portion and the boundary with the inner peripheral surface of the large-diameter portion It's fine formed by Ori , The inner circumferential surface of the inclined portion has a shape such that the fluid injection distance from the tip opening of the small diameter portion is longer than when the cross-sectional shape is a tapered shape with a constant incline. Catheter tube. [2] The catheter tube according to [1], wherein the shape is such that the spray distance is three times or more than that when the cross-sectional shape is a tapered shape with a constant incline. [3] When the shape is such that the cross-sectional shape is a tapered shape with a constant inclination, the degree of concavity k of the concave 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 = (Dt - Dr) / (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 catheter tube according to [1], wherein the inner diameter of the small diameter portion is 0.55 mm or less. [5] The catheter tube according to [4], wherein the inner diameter of the large diameter portion is 0.50 mm or more and 0.70 mm or less, the axial length of the inclined portion is 50 mm or more and 80 mm or less, and the inner diameter of the small diameter portion is 0.35 mm or more and 0.55 mm or less. 6 The concave curve has a slope of zero at the boundary with the inner peripheral surface of the small-diameter portion, and is a curve whose slope continuously or stepwise increases from the boundary with the inner peripheral surface of the small-diameter portion toward the boundary with the inner peripheral surface of the large-diameter portion. The catheter tube according to [1]. 7 The outer diameter size of the large-diameter portion is 2.0 Fr or more and 2.7 Fr or less. The catheter tube according to 1 above.​​ [ 8 The catheter tube has a tube lumen formed along the axial direction from a proximal opening to a distal opening, and when in use, it is inserted into a lumen in the body from the distal end, and the fluid introduced from the proximal opening is injected into the body through the tube lumen from the distal opening, the [ 7 Catheter tube as described in [ ]. [ 9 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. [ 10 ] 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 shape along the axial direction of the outer surface that is a concave curve passing inside the straight line connecting the boundary between the outer surface of the small diameter portion and the outer surface of the large diameter portion. It's fine The core wire preparation process involves preparing the core wires that have already been assembled, Outer surface of the core wire ni tree A coating formation step involves coating with oil to form a coating, The coating body is formed The continuous body is cut at predetermined positions of the large diameter portion and the small diameter portion of the core wire. With core wire 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.

[11] A method for manufacturing the catheter tube described in [9] 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 shape along the axial direction of the outer surface that is a concave curve passing inside the straight line connecting the boundary between the outer surface of the small diameter portion and the boundary between the outer surface of the large diameter portion and the outer surface, 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.

[12] A core wire used in the method for manufacturing a catheter tube as described in

[10] or

[11] above.

[13] A continuum used in the method for manufacturing a catheter tube as described in

[10] or

[11] above.

[14] A tube with a core wire used in the method for manufacturing a catheter tube as described in

[10] or

[11] above. [Effects of the Invention]

[0008] According to the present invention, the fluid injection distance from the tip opening can be increased compared to the case where the inner circumferential surface of the inclined portion connecting the large-diameter portion and the small-diameter portion has a tapered shape with a constant inclination. [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) are schematic diagrams showing 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 is a diagram illustrating an example of the use of a catheter tube. [Figure 8] Figure 8 shows the concave 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 concave 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 concave 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 concave curve that constitutes the inner surface of the inclined portion of Example 4, along with Comparative Examples 1 and 5. [Figure 12] Figure 12 shows the measurement results for torque. [Figure 13] Figure 13 is a diagram illustrating the torque testing apparatus. [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 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.

[0012] The catheter tube 1A has a tube lumen 10 formed along the axial direction from the proximal opening 10a to the distal opening 10b. The tube lumen 10 is defined by 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. In Figure 1(a), 2b is the outer surface of the large diameter section, 3b is the outer surface of the inclined section, and 4b is the outer surface of the small diameter section. 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. That is, when the catheter tube 1A is used, it is inserted into a lumen in the body from the distal end, and the fluid introduced from the proximal opening 10a is injected into the body through the tube lumen 10 and then into the body from the distal opening 10b.

[0013] As shown in Figure 1(b), the inner circumferential surface 3a of the inclined section is mainly composed of a concave curve whose cross-sectional shape along the axial direction is inside the straight line connecting the boundary P1 with the inner circumferential surface 4a of the small diameter section and the boundary P2 with the inner circumferential surface 2a of the large diameter section, i.e., the tapered line Lt (on the side of the central axis 10c of the tube lumen 10) (for example, when the concave curve occupies 80% or more of the axial length). The concave curve may be, for example, a curve in which the slope at the boundary P1 with the inner circumferential surface 4a of the small diameter section is zero, and the slope increases continuously or gradually from the boundary P1 towards the boundary P2 with the inner circumferential surface 2a of the large diameter section. By using such a curve, the position where the slope of the inner circumferential surface 3a of the inclined section is maximum can be made closer to the large diameter section 2, and as a result, the resistance when the fluid flows from the inclined section 3 to the small diameter section 4 is reduced, and the fluid injection distance from the tip opening 10b can be increased.

[0014] Next, the degree of concavity of the concave 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 boundary P1 and boundary P2), and Dr is the inner diameter of the concave curve along the vertical line Lv. Ld is the amount of concavity of the concave curve from the tapered line Lt, and can be expressed as (Dt-Dr) / 2. Here, "degree of concavity" is defined as the amount of concavity 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-Dr) / (Dt-Db)). From the viewpoint of increasing the fluid injection distance, the degree of the depression 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 0.60 mm, an outer diameter of 0.70 mm, and an axial length of 1200 mm. The axial length of the inclined section 3 is 70 mm. The small diameter section 4 has an inner diameter of 0.45 mm, an outer diameter of 0.55 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 0.50 to 0.70 mm and the inner diameter of the small diameter section 4 may be 0.35 to 0.55 mm, or the inner diameter of the large diameter section 2 may be 0.55 to 0.65 mm and the inner diameter of the small diameter section 4 may be 0.40 to 0.50 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 2.7 Fr (0.9 mm) or less. For example, a catheter tube 1A with an outer diameter of 2.0 Fr (approximately 0.7 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) are schematic diagrams showing the manufacturing method 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) According to the catheter tube 1A of this embodiment, the position where the inclination of the inner circumferential surface 3a of the inclined portion 3 is maximum can be made close to the large diameter portion 2. As a result, the resistance when the fluid flows from the inclined portion 3 to the small diameter portion 4 is reduced, and the fluid injection distance from the tip opening 10b is increased compared to the case where the inclination of the inner circumferential surface of the inclined portion is a constant tapered shape.

[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 concave curve whose cross-sectional shape along the axial direction of the outer surface passes inside (towards the central axis of the core wire 5) of the straight line connecting the boundary with the outer surface of the small diameter portion 53 and the boundary with the outer surface of the large diameter portion 51 (for example, when the concave 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 1 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 obtained from a single continuous catheter tube 100A, 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 an X-ray opaque 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 (die temperature) and a 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 such as nylon, 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 taken from a single continuous catheter tube 100B, thus improving productivity compared to manufacturing catheter tubes 1B one by one.

[0046] (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).

[0047] (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.

[0048] (Variation 3) A catheter tube can be made in which the tip end is more flexible than the proximal end by coating it with resins of gradually different flexibility from the large diameter section to the small diameter section.

[0049] (Example of use) Figure 7 illustrates an example of the use of catheter tubes 1A and 1B. When inserting catheter tubes 1A and 1B (hereinafter referred to as catheter tube 1) from an arteriole 20 into one of the peripheral blood vessels 21a and 21b, by following the guidewire 30, it is necessary that the catheter tube 1 has torque transmission performance (hereinafter referred to as torque performance) such that the torque from the proximal end is transmitted to the tip without attenuation when the catheter tube 1 is manipulated once the tip reaches the peripheral blood vessel 21a. High torque performance makes it easier to insert the tip of catheter tube 1 into the target peripheral blood vessel 21a. Note that the tip of the small diameter section 2 of catheter tube 1 may be curved depending on the purpose.

Example

[0050] Next, an example according to the first embodiment will be described.

[0051] (Example 1) FIG. 8 is a diagram showing a concave curve constituting the inner peripheral surface 3a of the inclined portion in Example 1, together with Comparative Example 1 and Comparative Example 2. Comparative Example 1 shows the case where the inner peripheral surface of the inclined portion is tapered, and Comparative Example 2 shows the case where the inner peripheral surface of the inclined portion is formed as a convex curved surface. The convex curve is a curve passing outside (the side opposite to the central axis 10c side of the tube lumen 10) of a taper line Lt connecting a boundary P1 between the inner peripheral surface 4a of the small-diameter portion and a boundary P2 between the inner peripheral surface 2a of the large-diameter portion (the same applies to FIGS. 9 to 11). In the figure, the horizontal axis indicates the axial length (x direction) from the boundary P1 (mm), and the vertical axis indicates the inner diameter (mm) in the radial direction (y direction) of the inner peripheral surface of the inclined portion (the same applies to FIGS. 9 to 11). Also, in the figure, the solid line indicates the actually measured value obtained by measuring the actually manufactured core wire, and the broken line indicates the approximated value obtained by approximating the actually measured value using a polynomial (the same applies to FIGS. 9 to 11).

[0052] The approximated formula of the concave curve in Example 1 can be expressed as follows. y = -3×10 -8 x 4 +6×10 -6 x 3 -0.0004x 2 +0.0123x + 0.225

[0053] The straight line in Comparative Example 1 can be expressed as follows. y = 0.0021x + 0.225

[0054] The approximated formula of the convex curve in Comparative Example 2 can be expressed as follows. y = 3×10 -8 x 4 -3×10 -6 x 3 +8×10 -5 x 2 -0.0004x + 0.225

[0055] (Example 2) Figure 9 shows the concave curve that constitutes the inner circumferential surface 3a of the inclined portion in Example 2, along with Comparative Examples 1 and 3. Comparative Example 1 shows the case where the inner circumferential surface of the inclined portion is tapered, and Comparative Example 3 shows the case where the inner circumferential surface of the inclined portion is constructed as a convex curved surface.

[0056] The approximate formula for the concave curve in Example 2 can be expressed as follows: y = -4 × 10 -8 x 4 +7 × 10 -6 x 3 -0.0004x 2 +0.0108x+0.225

[0057] The approximate formula for the convex curve in Comparative Example 3 can be expressed as follows: y = 4 × 10 -8 x 4 -5×10 -6 x 3 +0.0002x 2 -0.0012x+0.225

[0058] (Example 3) Figure 10 shows the concave 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 constructed as a convex curved surface.

[0059] The approximate formula for the concave curve in Example 3 can be expressed as follows: y = -3 × 10 -8 x 4 +5 × 10 -6 x 3 -0.0003x 2 +0.0095x+0.225

[0060] The approximate formula for the convex curve in Comparative Example 4 can be expressed as follows: y = 3 × 10 -8 x 4 -3 × 10 -6 x 3 +0.0001x 2 +0.0001x+0.225

[0061] (Example 4) Figure 11 shows the concave 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 convex curved surface.

[0062] The approximate formula for the concave curve in Example 4 can be expressed as follows: y = -3 × 10 -8 x 4 +5 × 10 -6 x 3 -0.0003x 2 +0.0078x+0.225

[0063] The approximate formula for the convex curve in Comparative Example 5 can be expressed as follows: y = 4 × 10 -9 x 4 -1 × 10 -17 x 3 -1 × 10 -5 x 2 +0.0013x+0.225

[0064] (Comparison experiment of fluid injection distance 1) Tables 1 and 2 show the results of comparative experiment 1 on fluid injection distance for Examples 1 to 4 and Comparative Examples 1 to 5 described above. If excessive positive pressure is applied during drug administration, the position of the tip of the catheter tube 1 may become unstable, potentially causing a kickback phenomenon where the tip moves away from contact with the blood vessel wall. To confirm that the drug reaches further peripherally when the same low positive pressure as during drug administration is applied, the fluid injection distance (straight-line distance) was evaluated. Specifically, a three-way stopcock was connected to the proximal end of the catheter tube (large diameter section length: 1500 mm, large diameter section inner diameter: 0.60 mm, inclined section length: 70 mm, small diameter section length: 80 mm, small diameter section inner diameter: 0.45 mm) used in the experiment. A syringe filled with a glycerin aqueous solution with a viscosity of 10 cP was attached to one end of the three-way stopcock. The stopcock was closed to create positive pressure in the syringe, then the stopcock was opened, and the fluid in the syringe was injected into the tube lumen 10 through the proximal end opening of the catheter tube. The distance (straight line distance) of the fluid ejected from the tip opening 10b was then measured. In Tables 1 and 2, the evaluation was as follows: △ for the ejection distance of Comparative Example 1, ○ for distances 10% or more longer than Comparative Example 1, and × for distances 10% or more shorter than Comparative Example 1.

[0065] [Table 1]

[0066] [Table 2]

[0067] (Torque comparison experiment 2) For Example 1, a catheter tube 1A with a large diameter section length of 1500 mm, an inner diameter of 0.60 mm, an inclined section length of 70 mm, a small diameter section length of 80 mm, and an inner diameter of 0.45 mm was used as the experimental subject. For Comparative Example 1, a catheter tube with a large diameter section length of 1500 mm, an inner diameter of 0.60 mm, an inclined section length of 70 mm, a small diameter section length of 80 mm, and an inner diameter of 0.45 mm was used as the experimental subject.

[0068] Figure 12 shows the results of the torque measurement. Torque was measured using the torque testing apparatus shown in Figure 13, which will be described later. Torque was evaluated by measuring the angle at which the tip of the catheter tube followed when the proximal end was rotated once at a rotational speed of 1 rpm.

[0069] Figure 13 is a diagram illustrating the torque testing apparatus. The torque testing apparatus 300 inserts the catheter tube 1 into a loop-shaped test tube 301 with an inner diameter of 200 mm, and when the proximal end of the large diameter section 2 is rotated once at a rotational speed of 1 rpm by the drive unit 302, the angle at which the tip end of the small diameter section 4 follows is measured by the angle detection unit 303.

[0070] (Evaluation results) From the results of Comparative Experiment 1, as shown in Tables 1 and 2, it was found that Examples 1 to 4, by mainly composing the shape of the inclined inner circumferential surface with a concave curve, could achieve a longer fluid injection distance than Comparative Example 1, and even longer than Comparative Examples 2 to 5.

[0071] As is clear from Figure 12, when the hand-held side is rotated 180 degrees, Comparative Example 1 rotates approximately 50 degrees, whereas Example 1 Since it rotated by approximately 114 degrees, it was found that Example 1 had superior torque performance compared to Comparative Example 1.

[0072] 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.

[0073] 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]

[0074] 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...Coating, 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, 300...Torque testing device, 301...Test tube, 302...Drive unit, 303...Angle detection unit, Lt...Tapered line, Lv...Vertical line, P1, P2...Boundary, P3...Intersection

Claims

1. A catheter tube comprising a large-diameter section, a small-diameter section whose inner diameter is smaller than the inner diameter of the large-diameter section, and an inclined section connecting the large-diameter section and the small-diameter section with an inclined inner 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 concave curve passing inside the straight line connecting the boundary between the inner circumferential surface of the small diameter portion and the boundary between the inner circumferential surface of the large diameter portion. The inner circumferential surface of the inclined portion has a shape such that the fluid injection distance from the tip opening of the small diameter portion is longer than when the cross-sectional shape is a tapered shape with a constant incline. Catheter tube.

2. The shape is such that the injection distance is three times or more than when the cross-sectional shape is a tapered shape with a constant inclination. 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 concavity k of the concave curve at the intermediate position in the axial direction of the inclined portion 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=(Dt-Dr) / (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 inner diameter of the small diameter portion is 0.55 mm or less. A catheter tube according to claim 1.

5. The inner diameter of the large diameter portion is 0.50 mm or more and 0.70 mm or less, the axial length of the inclined portion is 50 mm or more and 80 mm or less, and the inner diameter of the small diameter portion is 0.35 mm or more and 0.55 mm or less. A catheter tube according to claim 4.

6. The concave curve is a curve in which the slope is zero at the boundary with the inner surface of the small diameter portion, and the slope increases continuously or gradually from the boundary with the inner surface of the small diameter portion to the boundary with the inner surface of the large diameter portion. A catheter tube according to claim 1.

7. The outer diameter size of the large diameter portion is 2.0 Fr or more and 2.7 Fr or less. A catheter tube according to claim 1.

8. The catheter tube has a lumen formed along the axial direction from a proximal opening to a distal opening, and when in use, it is inserted into a lumen in the body from the distal end, and fluid introduced from the proximal opening is injected into the body through the lumen of the tube from the distal opening. A catheter tube according to claim 7.

9. 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.

10. 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 shape along the axial direction of the outer surface that is a concave curve passing inside the straight line connecting the boundary between the outer surface of the small diameter portion and the boundary between the outer surface of the large diameter portion and the outer surface, A coating body forming step, in which a resin is applied to the outer surface of the core wire to form a coating body, 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.

11. A method for manufacturing a catheter tube according to claim 9, 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 shape along the axial direction of the outer surface that is a concave curve passing inside the straight line connecting the boundary between the outer surface of the small diameter portion and the boundary between the outer surface of the large diameter portion and the outer surface, 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.

12. A core wire used in the method for manufacturing a catheter tube according to claim 10 or 11.

13. A continuous body used in the method for manufacturing a catheter tube according to claim 10 or 11.

14. A tube with a core wire used in the method for manufacturing a catheter tube according to claim 10 or 11.

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