Medical tubing

Abstract

The present invention provides medical tubing having raised portions on the outer circumferential surface thereof to reduce frictional resistance, inhibit sticking to objects of contact, facilitate the maintaining of proper shape, and suppress breakage.　A catheter (10) has a body (20) extending in a longitudinal direction X and comprising an inner layer (40), a stiffener (50) located on the radial outside of the inner layer (40), and an outer layer (60) covering the radial outside of the inner layer (40), wherein the stiffener (50) has at least one coiled wire (51) or a plurality of ring-shaped wires (51) arranged in the longitudinal direction (X), the outer layer (60) has covering portions (61) located on the radial outside of the wires (51) and intermediate portions (62) located between covering portions (61) adjacent in the longitudinal direction (X) and extending circumferentially, and the intermediate portions (62) have raised portions (63) protruding radially outward and extending circumferentially.

Description

Medical Tubes

[0001] The present invention relates to a medical tubular body such as a catheter or endoscope.

[0002] Intravascular treatment is performed to diagnose and treat lesions in blood vessels by percutaneously inserting a catheter into the blood vessel under radiographic guidance. It is desirable for the catheter to have low frictional resistance on its outer surface so that it can move through curved blood vessels and not stick to objects it comes into contact with.

[0003] For example, Patent Document 1 describes a catheter in which protrusions are formed on an outer layer located radially outward of a coiled reinforcing body, and the protrusions are covered with a lubricating layer. By having the protrusions on the outer peripheral surface, the catheter can reduce sliding resistance and prevent sticking to contact objects such as blood vessel walls.

[0004] Japanese Patent Application Laid-Open No. 2019-154827

[0005] When a catheter, which is a medical tubular body, has a convex portion on the outer peripheral surface where the reinforcing member is located, the wall thickness of the portion where the reinforcing member is not located tends to be thin, making the catheter prone to excessive bending at the thin portion. If the catheter is excessively bent, the lumen becomes narrow, making it difficult to pass a long device (e.g., a guidewire or another catheter) or a fluid (e.g., a drug, a contrast agent, or physiological saline) through the lumen, and the catheter may break at the bent position.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical tubing body that has a convex portion on its outer surface to reduce frictional resistance, prevent it from sticking to the object it comes into contact with, make it easier to maintain an appropriate shape, and prevent breakage.

[0007] The above object is achieved by the invention described in (1) below. (1) A medical tubing according to the present invention has a main body extending in a longitudinal direction, the main body including an inner layer, a reinforcing member located radially outward of the inner layer, and an outer layer covering the radially outer side of the inner layer, the reinforcing member having at least one coil-shaped wire or a plurality of ring-shaped wires aligned in the longitudinal direction, the outer layer having a covering portion located radially outward of the wire and an intermediate portion extending circumferentially and located between adjacent covering portions in the longitudinal direction, the intermediate portion having a convex portion that protrudes radially outward and extends circumferentially.

[0008] The medical tubing described in (1) above has protrusions on its outer surface, which reduce the contact area with the contact object, thereby reducing frictional resistance and preventing sticking to the contact object. Furthermore, the medical tubing has protrusions that reinforce its middle section, which is prone to bending due to the absence of wire rods on the radially inner side, and can prevent excessive bending in the middle section. Excessive bending of the medical tubing can narrow the lumen, making it difficult to pass wires or fluids through the lumen, and can lead to breakage at the bent position. In contrast, the present medical tubing can prevent excessive bending, making it easier to maintain an appropriate shape that allows for easy passage of wires and other components or fluids through the lumen, and can prevent breakage at the bent position.

[0009] (2) In the medical tubing described in (1) above, the wire may be coiled, and the protrusions may be spirally formed over substantially the entire length of the intermediate section. This allows the medical tubing to have protrusions over a wide area of ​​the outer circumferential surface of the main body, reducing frictional resistance over a wide area of ​​the main body, preventing the tubing from sticking to objects it comes into contact with, making it easier to maintain an appropriate shape, and reducing breakage.

[0010] (3) In the medical tubing described in (1) or (2) above, the difference between the maximum outer diameter of the intermediate portion and the minimum outer diameter of the covering portion may be 0.02 mm or more and 0.1 mm or less. This prevents the covering portion from coming into contact with the contact object when the protrusion of the intermediate portion comes into contact with the contact object, effectively reducing frictional resistance of the outer surface of the medical tubing and the occurrence of sticking to the contact object.

[0011] (4) In the medical tubing described in any one of (1) to (3) above, the maximum outer diameter of the main body may be 8 mm or more. As the maximum outer diameter of a medical tubing increases, the contact area with an object to be contacted increases, making it more likely that frictional resistance and sticking will occur. However, by providing the protrusions, frictional resistance and sticking can be effectively reduced even when the medical tubing has a large outer diameter of 8 mm or more.

[0012] Fig. 1 is a plan view showing a catheter according to the present embodiment; Fig. 2 is a plan view showing an enlarged view of a portion of the main body of the catheter; Fig. 3 is a cross-sectional view showing an enlarged view of a portion of the main body of the catheter; Fig. 4 is a plan view showing an enlarged view of a portion of the main body of a modified example of the catheter.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional proportions in the drawings may be exaggerated for convenience of explanation and may differ from the actual proportions. In the following description, the side of the catheter 10 (medical tubular body) that is operated will be referred to as the "proximal end" and the side that is inserted into the living body will be referred to as the "distal end."

[0014] As shown in Figures 1 to 3, a catheter 10 (medical tubular body) according to an embodiment of the present invention is used by being percutaneously inserted into a blood vessel under fluoroscopy for intravascular treatment to diagnose and treat lesions occurring in the blood vessel. The blood vessel to be treated by the catheter 10 and the blood vessel into which the catheter 10 is inserted (punctured) are not particularly limited. As an example, the catheter 10 is used to treat deep vein thrombosis (DVT). In this case, the catheter 10 is inserted into a vein at the thigh, knee, or more peripherally, and advanced into the blood vessel to be treated. The blood vessel to be treated is a vein more peripheral than the inferior vena cava (e.g., the iliac vein, femoral vein, or popliteal vein).

[0015] The catheter 10 has a tubular main body 20 having an inner lumen 21 formed along the longitudinal axis direction X through which a long device (e.g., a guidewire or another catheter) or a fluid (e.g., a drug, a contrast agent, or saline solution) can pass, a hub 30 fixed to the base end of the main body 20, and a kink-resistant protector 70.

[0016] The main body 20 has an inner layer 40, a reinforcing body 50 located radially outward of the inner layer 40, and an outer layer 60 covering the radially outer side of the inner layer 40. The radially outward direction is a direction perpendicular to the axis of the main body 20 and away from the axis. The radially inward direction is a direction perpendicular to the axis of the main body 20 and toward the axis.

[0017] The inner layer 40 is a layered member that forms the lumen 21 of the main body 20. The inner layer 40 is preferably formed from a low-friction material. This reduces resistance when a guidewire, another catheter, a drug, a contrast agent, physiological saline, or the like is passed through the lumen 21, thereby improving operability. Examples of low-friction materials include fluorine-based resin materials such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA). The inner layer 40 may also be formed from a material that is applicable to the outer layer 60, which will be described later.

[0018] The reinforcing member 50 is a member for reinforcing the main body 20 and includes a single wire 51 wound in a coil shape. The reinforcing member 50 may be a multi-thread coil formed by winding two or more circumferentially arranged wires 51 into a coil shape. The wire 51 is loosely wound with gaps in the longitudinal axis direction X of the main body 20. The material of the outer layer 60 or the inner layer 40 fills the gaps between the wires 51 in the reinforcing member 50. The wire 51 is formed of a metal such as stainless steel or NiTi. The cross-sectional shape of the wire 51 is not particularly limited and may be, for example, rectangular, square, circular, oval, or elliptical. The wire 51 may also be a bundle of two or more strands. The main body 20 having the reinforcing member 50 can ensure sufficient rigidity and strength without increasing the wall thickness, i.e., while relatively increasing the inner diameter of the main body 20.

[0019] The outer layer 60 is a member that covers the outside of the inner layer 40 and the reinforcing body 50. The outer layer 60 has a covering portion 61 located radially outside the wire 51 and an intermediate portion 62 located between adjacent covering portions 61 in the long axis direction X. The covering portion 61 is formed in a spiral shape along the wire 51. The intermediate portion 62 is formed in a spiral shape and extends circumferentially between adjacent covering portions 61 in the long axis direction X.

[0020] The outer layer 60 has, on the outer peripheral surface of the intermediate portion 62, convex portions 63 that protrude radially outward, and on the outer peripheral surface of the covering portion 61, concave portions 64 that are recessed between adjacent convex portions 63 in the long axis direction X. The outer peripheral surface of the outer layer 60 located at a boundary portion 65 between the intermediate portion 62 and the covering portion 61 in the long axis direction X is preferably inclined so that the outer diameter changes between the convex portions 63 and the concave portions 64, but it is also possible that the outer diameter does not change and the surface is not inclined.

[0021] The convex portion 63 is preferably formed without interruption over substantially the entire spiral intermediate portion 62. The convex portion 63 may be formed only in a portion of the spiral intermediate portion 62, rather than over the entire spiral intermediate portion 62, or may be formed in multiple divided portions. The outer diameter of the portion of the outer layer 60 where the convex portion 63 ends may be the same as the outer diameter of the concave portion 64, or may be larger than the outer diameter of the concave portion 64.

[0022] The recesses 64 are preferably formed without interruption over substantially the entire spiral covering portion 61. The recesses 64 may be formed only in a portion of the spiral covering portion 61, or may be divided into multiple portions. The outer diameter of the portion of the outer layer 60 where the recesses 64 end may be smaller than the outer diameter of the protrusions 63, or may be the same as the outer diameter of the protrusions 63.

[0023] Examples of materials constituting the outer layer 60 include polystyrene, polyolefin, polyurethane, polyester, polyamide, and various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based elastomers, and examples include combinations of one or more of these (polymer alloys, polymer blends, laminates, etc.). The materials constituting the outer layer 60 and the inner layer 40 may be different or the same.

[0024] The effective length of the catheter 10 is not particularly limited, but is preferably 650 mm to 900 mm. The effective length of the catheter 10 is the length of the portion that can be inserted into a blood vessel or a tubular device. In this embodiment, the effective length of the catheter 10 is the length from the most distal end of the anti-kink protector 70 at the proximal end to the most distal end of the main body 20. If the catheter 10 does not have the anti-kink protector 70, the effective length of the catheter 10 is the length from the most distal end of the hub 30 at the proximal end to the most distal end of the main body 20.

[0025] The difference between the maximum outer diameter D1 of the intermediate portion 62 (protrusion 63) and the minimum outer diameter D2 of the covering portion 61 (recess 64) is not particularly limited, but is preferably 0.02 mm to 0.1 mm, more preferably 0.02 mm to 0.08 mm, and even more preferably 0.03 mm to 0.06 mm. The maximum outer diameter D1 of the main body 20 is not particularly limited, but is preferably 2 mm to 11 mm, more preferably 3 mm to 11 mm, and even more preferably 4 mm to 11 mm. When the catheter 10 is used to treat deep vein thrombosis (DVT), for example, it is preferably 8 mm to 10 mm.

[0026] The main body 20 has convex portions 63 and concave portions 64 over substantially the entire longitudinal direction X. The main body 20 may have a flexible portion 22 at its tip end that does not have a reinforcing member 50 and does not have convex portions 63 or concave portions 64. This can reduce damage to contacting objects (e.g., blood vessels) when the catheter 10 having the flexible portion 22 is moved within a blood vessel. The main body 20 may, but does not have, a tapered portion 23 at its tip end, whose outer diameter decreases toward the tip. A catheter 10 having a tapered portion 23 can be easily pushed into narrow areas. The main body 20 may, but does not have to, have a curved portion 24 at its tip end. A catheter 10 having a curved portion 24 can adjust the direction of the tip end by rotating it, improving operability.

[0027] The entire body 20 or at least the outer circumferential surface of the distal end may be coated with a lubricious coating 25. The lubricious coating 25 is, for example, a hydrophilic polymer, such as a cellulose-based polymer, a polyethylene oxide-based polymer, a maleic anhydride-based polymer (e.g., a maleic anhydride copolymer such as a methyl vinyl ether-maleic anhydride copolymer), an acrylamide-based polymer (e.g., a polyacrylamide, a glycidyl methacrylate-dimethylacrylamide block copolymer), a water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, or a derivative thereof. Hydrophilic polymers form a strong water immobilization layer on their surface, exhibiting high affinity for the blood in blood vessels and the blood vessel walls, as well as low friction.

[0028] The main body 20 of the catheter 10 according to this embodiment can be manufactured by forming the outer layer 60 by extruding resin onto the outer surface of a tubular member having a reinforcing body 50 disposed on the outer surface of the inner layer 40. In this case, by adjusting (e.g., narrowing) the gap of the extrusion mold and adjusting (e.g., increasing) the resin pressure, it is possible to reduce the amount of resin coated onto the hard reinforcing bodies 50 and increase the amount of resin coated between the reinforcing bodies 50. This makes it possible to manufacture a main body 20 having recesses 64 in the coated portions 61 of the outer layer 60 and protrusions 63 in the middle portions 62.

[0029] As described above, the medical tubing according to this embodiment is a catheter 10 having a main body 20 extending in the longitudinal axis direction X and including an inner layer 40, a reinforcing member 50 positioned radially outward of the inner layer 40, and an outer layer 60 covering the radially outer side of the inner layer 40. The reinforcing member 50 includes at least one coiled wire 51. The outer layer 60 includes a covering portion 61 positioned radially outward of the wire 51 and an intermediate portion 62 positioned between adjacent covering portions 61 in the longitudinal axis direction X and extending circumferentially. The intermediate portion 62 includes a protruding portion 63 that protrudes radially outward and extends circumferentially. The protruding portion 63 on the outer peripheral surface of the catheter 10 reduces the contact area with an object, thereby reducing frictional resistance and preventing the catheter 10 from sticking to the object. Furthermore, the intermediate portion 62, which is prone to bending due to the absence of wire 51 on the radially inner side, is reinforced by the protruding portion 63, thereby preventing excessive bending of the intermediate portion 62. If the catheter 10 bends excessively, the lumen 21 may become narrow, making it difficult to pass an elongated device (e.g., a guidewire) or (e.g., a drug, a contrast agent, or physiological saline solution) through the lumen 21, and there is a possibility that the catheter may break at the bent position. In contrast, the present catheter 10 can suppress excessive bending, making it easier to maintain an appropriate shape that allows for easy passage of an elongated device or fluid through the lumen 21, and suppressing breakage at the bent position.

[0030] Furthermore, the wire 51 is coil-shaped, and the protrusions 63 are formed in a spiral shape over substantially the entire extension direction of the intermediate portion 62. That is, the protrusions 63 are formed without interruption over substantially the entire extension direction of the intermediate portion 62. As a result, the catheter 10 has the protrusions 63 over a wide range on the outer circumferential surface of the main body 20, which reduces frictional resistance over a wide range of the main body 20, suppresses sticking to objects in contact with the catheter, makes it easier to maintain an appropriate shape, and suppresses breakage.

[0031] Furthermore, the difference between the maximum outer diameter D1 of the intermediate portion 62 and the minimum outer diameter D2 of the covering portion 61 is 0.02 mm or more and 0.1 mm or less, which prevents the covering portion 61 from contacting the blood vessel wall (contact object) when the protrusion 63 of the intermediate portion 62 contacts the blood vessel wall, effectively reducing the frictional resistance of the outer surface of the catheter 10 and the occurrence of sticking to the contact object.

[0032] Furthermore, the maximum outer diameter D1 of the main body 20 may be 8 mm or more. As the maximum outer diameter of the catheter 10 increases, the contact area with the contact object increases, which increases the likelihood of frictional resistance and sticking. However, by providing the protrusions 63, it is possible to effectively reduce frictional resistance and sticking even when the catheter 10 has a large outer diameter of 8 mm or more.

[0033] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical spirit of the present invention. For example, as shown in a modified example in Fig. 4, the reinforcing member 50 may have a plurality of ring-shaped wire rods 52 arranged in the longitudinal axis direction X. In this case, the protrusions 63 and recesses 64 are also formed in a ring shape, and the plurality of protrusions 63 and the plurality of recesses 64 are alternately arranged in the longitudinal axis direction X.

[0034] Furthermore, the base end of the tapered portion 23 may be disposed in a range on the outer peripheral surface of the main body 20 that has the convex portions 63 and the concave portions 64. This effectively reduces the sliding resistance of the base end of the tapered portion 23 and the portion close to the base end of the tapered portion 23, which are likely to come into strong contact with the contact object. Furthermore, the curved portion 24 may be disposed in a range on the outer peripheral surface of the main body 20 that has the convex portions 63 and the concave portions 64. This effectively reduces the sliding resistance of the curved portion 24, which is likely to come into strong contact with the contact object. It is preferable that the entire curved portion 24 in the long axis direction X be located in a range on the outer peripheral surface of the main body 20 that has the convex portions 63 and the concave portions 64, but a portion of the curved portion 24 may be located.

[0035] Furthermore, the medical tubular body is not limited to the catheter 10, but may be, for example, an endoscope, a sheath, etc. The outer diameter of the endoscope is, for example, 5 mm to 15 mm.

[0036] This application is based on Japanese Patent Application No. 2024-047841 filed on March 25, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0037] REFERENCE SIGNS LIST 10 Catheter (medical tubular body) 20 Main body 40 Inner layer 50 Reinforcement body 51, 52 Wire rod 60 Outer layer 61 Covering portion 62 Middle portion 63 Convex portion 64 Concave portion X Long axis direction

Claims

1. A catheter having a main body extending in a longitudinal direction and including an inner layer, a reinforcing body located radially outside the inner layer, and an outer layer covering the radially outside of the inner layer, wherein the reinforcing body has at least one coil-shaped wire or a plurality of ring-shaped wires aligned in the longitudinal direction, and the outer layer has a covering portion located radially outside the wire and an intermediate portion located between adjacent covering portions in the longitudinal direction and extending circumferentially, and the intermediate portion has a convex portion that protrudes radially outward and extends circumferentially.

2. The catheter according to claim 1, wherein the wire is coil-shaped, and the protrusion is formed in a spiral shape over substantially the entire extension direction of the intermediate section.

3. A catheter according to claim 1 or 2, characterized in that the difference between the maximum outer diameter of said intermediate portion and the minimum outer diameter of said covering portion is 0.02 mm or more and 0.1 mm or less.

4. A catheter according to claim 1 or 2, characterized in that the maximum outer diameter of the main body is 8 mm or more.

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