Suction catheter

Abstract

The present invention provides a suction catheter for veins that is capable of effective suction while suppressing excessive deformation of and damage to a tip section.　Provided is a suction catheter (10) for veins comprising an elongate body tube (40) and a tubular distal-end tip (50) which is fixed to the distal-end side of the body tube (40), wherein: the distal-end tip (50) has an inner tapered surface (52) at which the inner diameter decreases toward the distal end and an outer tapered surface (51) at which the outer diameter decreases toward the distal end, and is formed from a resin which is harder than the resin from which the body tube (40) is formed; and a first inclination angle (α), which is the angle at which the inner tapered surface (52) is inclined with respect to the axis of the distal-end tip (50), is less than a second inclination angle (β), which is the angle at which the outer tapered surface (51) is inclined with respect to the axis of the distal-end tip (50).

Description

suction catheter

[0001] The present invention relates to a suction catheter.

[0002] Currently, catheters are sometimes used to remove foreign bodies such as blood clots that have formed in blood vessels. A catheter is a long medical device that is inserted percutaneously into a blood vessel, and can aspirate blood clots from an opening at the tip and expel them to the outside through a lumen at the hub at the base end.

[0003] When a thrombus formed in a vein is removed by suction, a guiding catheter or an introducer sheath is used as the catheter for suction.

[0004] International Publication No. 2013 / 002286

[0005] Guiding catheters and introducer sheaths usually have a flexible tip at the distal end where a distal opening is formed. For example, when aspirating a hard, large thrombus, the flexible tip of the guiding catheter or introducer sheath may bend, crush, or roll up due to the suction force. If the tip of the aspiration catheter becomes excessively deformed (bending, crushing, rolling, etc.), it becomes difficult to aspirate the thrombus, and the aspiration catheter must be replaced with another one, resulting in a delay in the procedure.

[0006] For example, Patent Document 1 describes an introducer sheath having a distal end that is formed with a higher degree of crystallinity than a proximal end and is harder than the proximal end in order to prevent curling of the distal end. However, because this introducer sheath has a thin distal end in order to improve insertability into the skin and blood vessels, it is difficult to reliably prevent excessive deformation or damage to the distal end.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a venous suction catheter that can perform effective suction while suppressing excessive deformation and damage to the tip.

[0008] The above object is achieved by the invention described in (1) below. (1) The suction catheter according to the present invention is a venous suction catheter having a long main tube and a tubular distal tip fixed to the distal end of the main tube, wherein the distal tip has an inner tapered surface whose inner diameter decreases toward the distal end and an outer tapered surface whose outer diameter decreases toward the distal end, and is formed of a resin harder than the resin forming the main tube, and wherein a first inclination angle, which is the angle at which the inner tapered surface is inclined with respect to the axis of the distal tip, is smaller than a second inclination angle, which is the angle at which the outer tapered surface is inclined with respect to the axis of the distal tip.

[0009] The suction catheter described in (1) above has an inner diameter larger than the distal tip toward the proximal end so that even large thrombi can be aspirated, while the inner diameter is reduced by the inner tapered surface of the distal tip, thereby concentrating and increasing the suction force. Furthermore, because the inner tapered surface has a first inclination angle smaller than the second inclination angle of the outer tapered surface, the distal tip gradually becomes thinner toward the distal end, while preventing the wall thickness at the distal end from becoming too thin, thereby maintaining sufficient strength. Therefore, when aspirating, for example, a hard, large thrombus, the suction catheter can effectively aspirate the thrombus by inserting the distal end and effectively breaking it down, while preventing excessive deformation or damage to the distal end.

[0010] (2) In the suction catheter described in (1) above, the second inclination angle may exceed 15 degrees. This allows the suction catheter to effectively increase suction power by reducing the inner diameter of the tip, and to effectively destroy thrombi by reducing the outer diameter of the tip, thereby suppressing deformation during insertion.

[0011] (3) In the suction catheter according to (1) or (2), the joint between the distal tip and the main tube may be inclined with respect to a plane perpendicular to the axis of the distal tip, thereby ensuring a large joint area of ​​the suction catheter and achieving high joint strength.

[0012] Fig. 2 is a plan view showing the suction catheter according to the present embodiment;Fig. 3 is an enlarged cross-sectional view showing the distal end of the suction 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 suction catheter 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] 1 and 2, a suction catheter 10 according to an embodiment of the present invention is a long medical device that is percutaneously inserted into a blood vessel and used to aspirate and remove thrombi and the like that have formed in a vein. The blood vessel that can be treated with the suction catheter 10 is not particularly limited as long as it is a vein.

[0015] The suction catheter 10 has a tubular main body 20 having a lumen 21 formed along the longitudinal axis X, through which objects such as a wire (e.g., a guidewire) or a thrombus can pass, a hub 30 fixed to the proximal end of the main body 20, and a kink-resistant protector 70. At least the outer and inner surfaces of the distal end of the main body 20 may be coated with a lubricating coating. The lubricating coating may be made of, for example, a hydrophilic polymer or a fluorine-based resin material.

[0016] The hub 30 has a base end opening 31 that opens at the base end surface of the hub 30 and communicates with the lumen 21 of the main body 20, and a suction port 32 that opens at the side of the hub 30 and communicates with the lumen 21 of the main body 20. A syringe or the like can be connected to the suction port 32 to apply suction force to the lumen 21 of the main body 20. A valve may be disposed in the base end opening 31.

[0017] The main body 20 has a main body tube 40 that is long in the longitudinal axis direction X, and a tubular distal tip 50 that is fixed to the distal end side of the main body tube 40 .

[0018] The main tube 40 includes an inner layer 41, a reinforcing member 42 located radially outward of the inner layer 41, an outer layer 43 covering the radially outer sides of the inner layer 41 and the reinforcing member 42, and a contrast marker 44 that is radiopaque. The radially outward direction is a direction perpendicular to the axis of the main body 20, moving away from the axis. The radially inward direction is a direction perpendicular to the axis of the main body 20, moving closer to the axis. The main tube 40 may or may not have a curved portion 46 at its tip. The suction catheter 10 with the curved portion 46 can adjust the direction of the tip by rotating it, allowing the direction of suction to be selected. The suction catheter 10 includes the reinforcing member 42 in the main tube 40 and has high torque transmission, allowing the direction of suction to be easily selected.

[0019] The inner layer 41 is a layered member that forms the inner cavity 21 of the main body 20. The inner layer 41 has a substantially constant inner diameter D2 in the longitudinal axis direction X.

[0020] The reinforcing member 42 reinforces the main body 20 and includes multiple wires 45 braided in a tubular shape. The reinforcing member 42 may be a coil formed by spirally winding one or more wires 45 or a multi-thread coil formed by winding two or more circumferentially arranged wires 45 in a coil shape. The wires 45 are loosely wound with gaps in the longitudinal axis direction X of the main body 20. The material of the outer layer 43 or inner layer 41 fills the gaps between the wires 45 in the reinforcing member 42. The wires 45 are formed of a metal such as stainless steel or NiTi. The cross-sectional shape of the wires 45 is not particularly limited and may be, for example, rectangular, square, circular, oval, or elliptical. The wires 45 may also be a bundle of two or more strands. The main body 20 having the reinforcing member 42 can ensure sufficient rigidity and strength without increasing the wall thickness, i.e., while relatively increasing the inner diameter of the main body 20.

[0021] The outer layer 43 is a member that covers the radial outside of the inner layer 41 and the reinforcing body 42. The outer layer 43 has a substantially constant outer diameter in the long axis direction X.

[0022] The inner layer 41 and the outer layer 43 are both formed of a resin that is more flexible than the distal tip 50. The inner layer 41 and the outer layer 43 may be formed of the same material or different materials. Examples of materials that can be used for the inner layer 41 and the outer layer 43 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 thermoplastic elastomers, as well as combinations of one or more of these (polymer alloys, polymer blends, laminates, etc.). Thermoplastic elastomers are preferred, and thermoplastic elastomers with a Shore D hardness of 60 or less are more preferred.

[0023] The main tube 40 has a distal fixing surface 47 that faces the distal end and is fixed to the distal tip 50. The distal fixing surface 47 is inclined with respect to a plane perpendicular to the axis of the main body 20 so that the inner diameter tapers off toward the proximal end. This ensures a wide area for fixing the main tube 40 and the distal tip 50, and allows the distal tip 50 to be firmly fixed to the main tube 40.

[0024] The distal end fixing surface 47 may be inclined with respect to the axis of the main body 20 so that the outer diameter increases in a tapered manner toward the base end. Even in this case, a large area can be secured over which the main body tube 40 and the distal tip 50 are fixed. Alternatively, the distal end fixing surface 47 may be formed perpendicular to the axis of the main body 20.

[0025] The outer diameter D1 of the main tube 40 is preferably 3.3 mm or more and 5.6 mm or less, for example, 4.5 mm. The inner diameter D2 of the main tube 40 is preferably 2.8 mm or more and 5.2 mm or less, for example, 4.0 mm. The outer diameter D1 and inner diameter D2 of the main tube 40 are constant along the longitudinal axis direction X, but may vary slightly, for example, may decrease at the distal end near the distal tip 50. If the outer diameter D1 of the main tube 40 decreases at the distal end near the distal tip 50, the outer periphery of the proximal end of the rigid distal tip 50 does not form the maximum outer diameter portion of the main body 20, making it less likely to come into contact with the blood vessel, thereby reducing damage to the blood vessel.

[0026] The distal tip 50 has an outer tapered surface 51 whose outer diameter tapers distally, an inner tapered surface 52 whose inner diameter tapers distally, a distal surface 53 facing the distal end, and a proximal fixed surface 54 facing the proximal end and fixed to the main tube 40. The proximal end of the distal tip 50 is preferably located distally of the forefront of the reinforcing member 42. The distal tip 50 is formed of a resin that is harder than the resin forming the main tube 40, i.e., the resin forming the inner layer 41 and the outer layer 43. Examples of the resin 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 thermoplastic elastomers. Examples include combinations of one or more of these (polymer alloys, polymer blends, laminates, etc.). Thermoplastic elastomers are preferred, and thermoplastic elastomers or thermoplastic resins having a Shore D hardness of greater than 60 are more preferred. As an example, the material of the inner layer 41 and the outer layer 43 is a polyamide elastomer having a Shore D hardness of 47, and the material of the distal tip 50 is a polyamide having a Shore D hardness of 75.

[0027] The second inclination angle β, which is the angle at which the outer tapered surface 51 is inclined with respect to the axis of the main body 20, is preferably greater than 0 degrees and less than or equal to 30 degrees, more preferably greater than 15 degrees, and is, for example, 20 degrees. The first inclination angle α, which is the angle at which the inner tapered surface 52 is inclined with respect to the axis of the main body 20, is smaller than the second inclination angle β and is preferably greater than 0 degrees and less than or equal to 20 degrees, more preferably greater than or equal to 5 degrees and less than or equal to 10 degrees, and is, for example, 7.5 degrees. The tip surface 53 is formed approximately perpendicular to the axis of the main body 20.

[0028] The angle (β-α) obtained by subtracting the first tilt angle α from the second tilt angle β is preferably greater than 0 degrees and equal to or less than 30 degrees, and more preferably 5 to 15 degrees.

[0029] The length L1 of the outer tapered surface 51 in the major axis direction X is preferably 1.5 mm or more and 5 mm or less, for example, 3 mm. The outer diameter D3 of the outer tapered surface 51 at its narrowest tip is preferably 2.8 mm or more and 5.6 mm or less, for example, 3.5 mm.

[0030] The length L2 of the inner tapered surface 52 in the major axis direction X is preferably 2 mm or more and 5 mm or less, for example, 3.5 mm. The inner diameter D4 of the inner tapered surface 52 at its narrowest tip is preferably 2.8 mm or more and 5.2 mm or less, for example, 3.3 mm.

[0031] The thickness ((D3-D4) / 2) of the tip where the tip surface 53 of the tip tip 50 is formed is preferably 0 mm or more and 0.5 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less.

[0032] The effective length of the suction catheter 10 is not particularly limited, but is, for example, 300 mm to 1150 mm, and is, for example, 900 mm. The effective length of the suction 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 suction catheter 10 is the length from the tip of the hub 30 or the anti-kink protector 70 at the proximal end to the tip of the main body 20.

[0033] As described above, the suction catheter 10 according to this embodiment is a venous suction catheter 10 having a long main tube 40 and a tubular distal tip 50 fixed to the distal end of the main tube 40, the distal tip 50 having an inner tapered surface 52 whose inner diameter decreases toward the distal end and an outer tapered surface 51 whose outer diameter decreases toward the distal end, and is formed of a resin harder than the resin forming the main tube 40, and the first inclination angle α, which is the angle at which the inner tapered surface 52 is inclined relative to the axis of the distal tip 50, is smaller than the second inclination angle β, which is the angle at which the outer tapered surface 51 is inclined relative to the axis of the distal tip 50. As a result, the suction catheter 10 has a large inner diameter on the proximal side beyond the distal tip 50 so that even large thrombi can be aspirated, and the inner diameter is reduced by the inner tapered surface 52 of the distal tip 50, thereby concentrating and increasing suction force. Furthermore, because the inner tapered surface 52 has a first inclination angle α that is smaller than the second inclination angle β of the outer tapered surface 51, the distal tip 50 can be gradually tapered toward the distal end while preventing the distal end from becoming too thin, thereby maintaining sufficient strength. Therefore, when aspirating a hard, large thrombus, for example, the suction catheter 10 can thrust the distal end to effectively break up the thrombus and perform effective suction, while also preventing excessive deformation (for example, bending, crushing, or curling) or damage to the distal end.

[0034] Since the present suction catheter 10 is designed for use in veins with low blood pressure and therefore poses a low risk of severe bleeding due to vascular perforation, a distal tip 50 made of a harder resin than the main tube 40 can be used. Furthermore, because the distal tip 50 is made of resin rather than metal, it can deform to a certain extent, thereby minimizing damage to the blood vessel. Metal distal tips are virtually indeformable, meaning they cannot be deformed along with the thrombus contained in the lumen while being retrieved into a sheath, etc., and in some cases, the thrombus may fall off the distal tip. In contrast, the present suction catheter 10 has a distal tip 50 made of resin, which allows it to deform to a certain extent, allowing it to be retrieved into a sheath, etc., while deforming along with the thrombus contained in the lumen 21. Furthermore, when using the suction catheter 10, a protector such as a filter is typically placed in the blood vessel distal to the suction position. If the distal tip 50 is made of resin and is deformable, interference with the protector, such as getting caught on the protector, can be reduced.

[0035] Furthermore, the suction catheter 10 is intended to be inserted into a blood vessel via a guiding catheter, an introducer sheath, etc., and is not inserted directly into the blood vessel at the puncture site. Therefore, the suction catheter 10 does not need to be thinner toward the tip in order to be inserted directly into the blood vessel, and can be inserted into the blood vessel even if the tip is somewhat thick.

[0036] In addition, the second inclination angle exceeds 15 degrees. As a result, the suction catheter 10 can concentrate and effectively increase the suction force by reducing the inner diameter of the tip, and can effectively destroy thrombi by suppressing deformation during insertion by reducing the outer diameter of the tip.

[0037] In addition, the joint between the distal tip 50 and the main tube 40 is inclined with respect to a plane perpendicular to the axis of the distal tip 50. This ensures a wide joint area for the suction catheter 10, thereby achieving high joint strength.

[0038] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical concept of the present invention. For example, the main body 20 may have a curved portion 46 with a curved axis at the tip, but it is not necessary to have such a portion. The suction catheter 10 having the curved portion 46 can be rotated to adjust the direction of the tip, thereby improving operability.

[0039] This application is based on Japanese Patent Application No. 2024-148181 filed on August 30, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0040] 10 suction catheter 20 main body 21 lumen 40 main body tube 47 distal end fixing surface 50 distal tip 51 outer tapered surface 52 inner tapered surface 53 distal end surface 54 proximal end fixing surface X long axis direction

Claims

1. A suction catheter for intravenous use having a long main tube and a tubular distal tip fixed to the distal end of the main tube, wherein the distal tip has an inner tapered surface whose inner diameter decreases toward the tip and an outer tapered surface whose outer diameter decreases toward the tip, and is formed from a resin harder than the resin forming the main tube, and wherein a first inclination angle, which is the angle at which the inner tapered surface is inclined relative to the axis of the distal tip, is smaller than a second inclination angle, which is the angle at which the outer tapered surface is inclined relative to the axis of the distal tip.

2. The aspiration catheter of claim 1, wherein the second angle of inclination is greater than 15 degrees.

3. The suction catheter according to claim 1 or 2, wherein the joint between the distal tip and the main tube is inclined with respect to a plane perpendicular to the axis of the distal tip.

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