Catheters and Aspiration Systems

Abstract

To provide a catheter of a new structure capable of securing rigidity, push-in properties, torque transmission properties, and kink resistance of the catheter while keeping the thickness of the catheter small.SOLUTION: A catheter 50 includes a slender lumen LM along a longitudinal axis, and is provided with an inner layer member 61 having an inner peripheral surface 61a that comes in contact with the lumen LM, an outer layer member 62 having an outer peripheral surface 62a of the catheter 50, a coil-like first reinforcement member 71 provided outside the inner layer member 61 between the inner peripheral surface 61a and the outer peripheral surface 62a, a braid-like second reinforcement member 72 provided outside the first reinforcement member 71 between the inner peripheral surface 61a and the outer peripheral surface 62a, and so on.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a catheter that is percutaneously introduced into a body, and to an aspiration system for removing foreign bodies such as thrombi present in blood vessels. [Background technology]

[0002] When a foreign body such as a thrombus clogs a cerebral blood vessel (main cerebral artery) and causes cerebral infarction (acute cerebral artery occlusion), a method of dissolving the foreign body using a drug is known. However, depending on the patient, this drug may not work effectively or may not be applicable. In such cases, a catheter is percutaneously introduced into the body, and then a flexible core wire called a separator is inserted into the catheter, and the foreign body is mechanically crushed or entangled by the movement of the separator, and then sucked out of the blood vessel and removed, or the foreign body is entangled by a stent retriever (stent-type thrombus retrieval device) to reopen the cerebral blood vessel.

[0003] Catheters must be inserted into blood vessels in the arms, legs, etc., and their tip must reach the treatment site reliably, so they must have characteristics such as pushability, torque performance, flexible bending, restorability, kink resistance, etc. The following patent documents disclose catheters equipped with a reinforcing structure to achieve these characteristics. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-189213 A [Patent Document 2] JP 2005-296078 A [Patent Document 3] Japanese Patent Application Publication No. 10-57495 [Patent Document 4] Patent No. 5659788 [Patent Document 5] JP 2010-88833 A Summary of the Invention [Problem to be solved by the invention]

[0005] The tip of the catheter is required to have flexibility and restorability, etc., since it advances through a blood vessel having a thin and complex shape. On the other hand, the base end of the catheter is required to have relatively high rigidity, pushability, torque transmission, kink resistance, etc., since it transmits the operation of the operator to the entire catheter. In addition, in order to insert and remove medical devices / instruments through the catheter lumen and to maintain the suction force of thrombus, it is preferable that the catheter has a large inner diameter. However, in order to ensure the insertability into blood vessels and the operability within blood vessels, the outer diameter of the catheter is limited to a certain extent. Therefore, if the inner diameter of the catheter is increased, the thickness of the catheter is reduced and the strength is reduced, which results in a decrease in pushability, torque transmission, and kink resistance.

[0006] An object of the present invention is to provide a catheter of a novel structure that can ensure the rigidity, pushability, torque transmission, and kink resistance of the catheter while maintaining a small thickness of the catheter.

[0007] It is also an object of the present invention to provide an aspiration system using such a catheter. [Means for solving the problem]

[0008] In order to achieve the above object, the catheter according to the present invention comprises: A catheter having an elongated lumen along a longitudinal axis, an inner layer member having an inner circumferential surface in contact with the lumen; an outer layer member having an outer peripheral surface of the catheter; a coil-shaped first reinforcing member provided outside the inner layer member between the inner circumferential surface and the outer circumferential surface; and a blade-shaped second reinforcing member provided outside the first reinforcing member between the inner circumferential surface and the outer circumferential surface.

[0009] According to the present invention, not only the first coil-shaped reinforcing member but also the braid-shaped second reinforcing member is provided between the inner and outer circumferential surfaces of the catheter. When the catheter is bent, the gaps between the coils become smaller inside the curved portion, compressing the outer layer member, while the gaps between the coils become larger outside the curved portion, causing the outer layer member to expand. If the curve becomes even larger, the outer layer member may expand further and break. As a countermeasure, by providing a braid-shaped second reinforcing member on the outside of the first reinforcing member, the stress generated outside the curved portion can be supported by the second reinforcing member, thereby preventing the outer layer member from breaking. As a result, it is possible to maintain strength even if the catheter is thin, and pushability, torque transmission, and kink resistance can be ensured.

[0010] In the present invention, the second reinforcing member is preferably configured as a long member made of synthetic resin.

[0011] According to this aspect, by using a more flexible and easily processable synthetic resin, a flat reinforcing member with a small thickness can be realized, which allows the thickness of the catheter to be further reduced while maintaining its strength.

[0012] In the present invention, the long member is preferably formed of a bundle of a plurality of fibers.

[0013] According to this embodiment, the stiffness and flexibility of the catheter can be adjusted by increasing or decreasing the number of fibers. That is, a catheter with desired performance can be easily realized by increasing or decreasing the number of fibers, since a catheter with a reduced number of fibers has a higher flexibility and a catheter with a higher stiffness can be easily realized by increasing or decreasing the number of fibers. In addition, since the long member is composed of a plurality of fibers, even if a part of the long member is damaged, i.e., even if a part of the plurality of fibers is broken, the catheter does not immediately kink, and a catheter with excellent durability can be obtained.

[0014] In the present invention, the first reinforcing member is preferably made of a wire having a rectangular cross section.

[0015] According to this aspect, the strength per unit length of the catheter can be increased.

[0016] In the present invention, the first reinforcing member is preferably made of a metal wire.

[0017] According to this aspect, the first reinforcing member can have high strength and can support the stress generated in the curved portion of the catheter.

[0018] In the present invention, the second reinforcing member is preferably provided in an area at a predetermined distance from the proximal end.

[0019] According to this aspect, by providing a region with the second reinforcing member and a region without the second reinforcing member, it is possible to realize a catheter having different characteristics in each region.

[0020] The suction system according to the present invention further comprises: The catheter described above, and a suction pump connected to the catheter.

[0021] According to the present invention, a catheter having a large inner diameter capable of maintaining a high suction force, a small outer diameter allowing for excellent insertability into blood vessels and maneuverability within blood vessels, etc., and sufficient strength is used, making it possible to efficiently remove foreign bodies such as thrombi present within blood vessels. Effect of the Invention

[0022] According to the present invention, it is possible to provide a catheter having a novel structure that can ensure the rigidity, pushability, torque transmission, and kink resistance of the catheter while maintaining a small thickness of the catheter, and also to provide an aspiration system using such a catheter. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a side view showing one embodiment of a catheter according to the present invention. [Diagram 2] FIG. 2 is a partial side view of the proximal end of the catheter shown in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 3 is a longitudinal cross-sectional view along the longitudinal axis corresponding to the partial side view of FIG. 2. [Diagram 5] FIG. 2 is a side view showing another embodiment of a catheter according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0025] [1. Catheter] FIG. 1 is a side view showing one embodiment of a catheter according to the present invention. The catheter 50 is a hollow member having an elongated lumen along the longitudinal axis. For ease of understanding, the catheter 50 is roughly divided into a tip portion SA, a middle portion SB, and a base portion SC, and is configured such that the geometric shapes such as the outer diameter and the inner diameter, and the physical properties such as elasticity and restorability change continuously and / or stepwise from the proximal end of the base portion SC to the distal end of the tip portion SA. For example, the outer diameter of the catheter 50 changes in the range of 1.7 mm to 2.2 mm, and the inner diameter changes in the range of 1.5 mm to 1.8 mm. The tip portion SA, the middle portion SB, and the base portion SC can be further divided into a plurality of regions having different geometric shapes and physical properties. It is also possible to make the geometric shapes and physical properties the same from the proximal end of the base portion SC to the distal end of the tip portion SA.

[0026] The tip portion SA is set in an area at a predetermined distance from the distal end and includes a tube 53 having an elongated lumen along the longitudinal axis. A tip tip 51 made of a flexible material that is gentle on blood vessels is attached to the distal end of the tube 53. An X-ray contrast marker 52 made of a Pt alloy or the like is attached near the tip tip 51.

[0027] The base end SC is set in a region a predetermined distance from the proximal end and includes a tube 55 having an elongated lumen along a longitudinal axis. The middle section SB is set in a region between the tip end SA and the base end SC and includes a tube 54 having an elongated lumen along a longitudinal axis. The tubes 53, 54, and 55 may be connected using known joining techniques, such as welding, adhesive bonding, crimping, melting, etc., or may be formed integrally.

[0028] A hub 57 having radially extending fins 58 is connected to the proximal end of tube 55. Hub 57 is a hollow member and is in fluid communication with tubes 53, 54, and 55. A strain relief 56 is attached to the distal side of hub 57 so as to cover tube 55 to prevent kinking.

[0029] Fig. 2 is a partial side view of the proximal end SC of the catheter 50 shown in Fig. 1. Fig. 3 is a transverse cross-sectional view taken along line AA in Fig. 1. Fig. 4 is a longitudinal cross-sectional view taken along the longitudinal axis corresponding to the partial side view in Fig. 2.

[0030] The tube 55 includes an inner layer member 61, an outer layer member 62, a first reinforcing member 71, and a second reinforcing member 72. The inner layer member 61 has an inner circumferential surface 61a that contacts the lumen LM. The outer layer member 62 has an outer circumferential surface 62a of the catheter 50. The first reinforcing member 71 is provided outside the inner layer member 61, between the inner circumferential surface 61a and the outer circumferential surface 62a. The second reinforcing member 72 is provided outside the first reinforcing member 71, between the inner circumferential surface 61a and the outer circumferential surface 62a.

[0031] The inner layer member 61 is preferably made of a fluorine-based thermoplastic synthetic resin, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy fluorine resin (PFA), etc., and is more preferably made of polytetrafluoroethylene (PTFE). Although the inner layer member 61 is exemplified here as a single-layer tube, it may be a multi-layer tube made of the same or different materials.

[0032] The outer layer member 62 is preferably made of a thermoplastic synthetic resin, such as polyether block amide (PEBA), polyethylene (PE), polypropylene (PP), polyamide (PA), polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polyurethane (PU), nylon elastomer, ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVC), etc., and is more preferably made of polyamide (PA). The outer peripheral surface 62a of the outer layer member 62 is preferably coated with a hydrophilic coating such as hyaluronic acid, polyvinylpyrrolidone, polyvinyl alcohol (PVA), etc. The outer layer member 62 is illustrated here as a single-layer tube, but may be a multi-layer tube made of the same or different materials.

[0033] The first reinforcing member 71 is formed in a coil shape. In other words, the first reinforcing member 71 has a structure in which a wire is wound in a spiral shape clockwise or counterclockwise along the longitudinal axis. The spiral lead angle α of the first reinforcing member 71 (the inclination angle of the spiral with respect to the perpendicular plane of the longitudinal axis) is set in the range of 0°<α<90°, preferably 0°<α≦15°, and more preferably 0°<α≦10°. The lead angle α may vary along the longitudinal axis, and may, for example, increase continuously and / or stepwise from the proximal end to the distal end of the catheter.

[0034] The first reinforcing member 71 can be preferably made of a metal wire, for example, a wire made of stainless steel (SUS), NiTi alloy, etc. In this way, when the catheter is curved, the first reinforcing member 71 can support the stress generated on the outside of the curved part, thereby suppressing deformation of the outer layer member 62.

[0035] The cross-sectional shape of the first reinforcing member 71 may be a perfect circle, ellipse, square, rectangle, polygon, etc., but it is preferable to use a wire having a rectangular cross section, so-called flat wire, in order to increase the strength per unit length.

[0036] The second reinforcing member 72 is formed in a braid shape. In other words, the second reinforcing member 72 constitutes a tubular braided body in which a first group in which a plurality of elongated members (for example, 4 to 8 members) are arranged at equal intervals around the longitudinal axis and spirally wound clockwise along the longitudinal axis and a second group in which a plurality of elongated members (for example, 4 to 8 members) are arranged at equal intervals around the longitudinal axis and spirally wound counterclockwise along the longitudinal axis are alternately overlapped. Such a long member may be hollow or solid, and the length of the long member in the short direction can be freely selected as long as it can constitute a tubular braided body, and it may be linear or strip-shaped.

[0037] The helical lead angle β of the second reinforcing member 72 (the inclination angle of the helix with respect to a plane perpendicular to the longitudinal axis) is set in the range of 0°<β≦90°, preferably 15°≦β≦75°, and more preferably 30°≦β≦60°. Here, the lead angle β of the second reinforcing member 72 is larger than the lead angle α of the first reinforcing member 71, i.e., it is preferable that α<β is satisfied, and this makes it possible to support both the longitudinal and circumferential components of the stress generated in the catheter. The lead angle β may vary along the longitudinal axis, and may, for example, increase continuously and / or stepwise from the proximal end to the distal end of the catheter.

[0038] The second reinforcing member 72 can be preferably made of a long member made of synthetic resin, such as a long member made of nylon resin, polyethylene resin, polyetheretherketone (PEEK), polysulfone (PSF), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), or a long member made of metal, such as a long member made of stainless steel (SUS), NiTi alloy, or a long member made of carbon fiber, glass fiber, or the like, and is more preferably made of a long member made of nylon resin. As a result, when the catheter is curved, the stress generated on the outside of the curved part can be supported by both the first reinforcing member 71 and the second reinforcing member 72, so that deformation and breakage of the outer layer member 62 can be suppressed.

[0039] One long member constituting the second reinforcing member 72 is preferably composed of a bundle of a plurality of fibers 73, thereby realizing a reinforcing member that is flat, thin, and has high strength. In Figs. 3 and 4, a case where one long member is composed of a bundle of eight fibers 73 is illustrated, but it is also possible to compose it with a bundle of 2 to 7 or 9 or more fibers 73. In Figs. 3 and 4, a case where a plurality of fibers 73 are arranged in a line so as to be adjacent to each other in the circumferential direction is illustrated, but it is also possible to arrange the fiber bundle so that the cross section is a perfect circle, ellipse, square, rectangle, or polygon. Such fibers may be hollow or solid.

[0040] Next, an example of a method for manufacturing a catheter will be described, but the method is not limited to this. First, a tubular inner layer member 61 is prepared. Next, a first reinforcing member 71 is wound in a coil shape around the outer peripheral surface of the inner layer member 61. Next, a second reinforcing member 72 is woven in a braid shape around the outer peripheral surface of the first reinforcing member 71. Next, a material for the outer layer member 62 is applied to the outer peripheral surface and cured to form the outer layer member 62. In this manner, the tube 55 that constitutes the base end SC is obtained.

[0041] In the above-described embodiment, a structure in which the first reinforcing member 71 contacts the outer peripheral surface of the inner layer member 61 is exemplified, but the first reinforcing member 71 may be separated from the outer peripheral surface of the inner layer member 61 or may be partially embedded inside the inner layer member 61.

[0042] In addition, in the above-described embodiment, a structure in which the second reinforcing member 72 is in contact with the outer peripheral surface of the first reinforcing member 71 has been exemplified, but the second reinforcing member 72 may be separated from the outer peripheral surface of the first reinforcing member 71.

[0043] Tube 53 constituting tip portion SA and tube 54 constituting intermediate portion SB have a structure obtained by omitting second reinforcing member 72 from the structure of tube 55. Also, the cross-sectional shape of first reinforcing member 71 in tubes 53 and 54 may be a perfect circle, ellipse, square, rectangle, polygon, etc., but it is preferable to use a wire having a perfect circle cross section, a so-called round wire, in order to increase flexibility per unit length.

[0044] Fig. 5 is a side view showing another embodiment of the catheter according to the present invention. Tube 53 constituting tip section SA and tube 54 constituting intermediate section SB also have the structures shown in Fig. 2 to Fig. 4, and are provided with braid-shaped second reinforcing member 72, similar to tube 55 constituting base section SC. This structure ensures rigidity, pushability, torque transmission, and kink resistance throughout the entire catheter.

[0045] In the above embodiment, the catheter 50 is a single lumen type, but the present invention can also be applied to double lumen and triple lumen type catheters.

[0046] In the above embodiment, the catheter 50 is an over-the-wire type, but the present invention can also be applied to a rapid exchange type catheter in which a guidewire lumen is provided independently.

[0047] In addition, in the above-described embodiment, the catheter 50 is percutaneously introduced into a blood vessel, but the present invention is also applicable to catheters introduced into body cavities such as the thoracic cavity and abdominal cavity, the digestive tract such as the mouth and anus, the ureter, etc.

[0048] [2. Suction system] The suction system according to the present invention includes the above-mentioned catheter 50 and a suction pump connected to the catheter 50.

[0049] When using such an aspiration system, the operator operates the catheter 50 while checking an X-ray contrast marker provided on the catheter 50 under X-ray imaging. The operator advances and positions the catheter 50, for example, from the femoral artery toward a site of thrombus occlusion in a cerebral blood vessel. Next, when the operator activates the aspiration pump, the thrombus moves inside the catheter 50 and is removed outside the body. The operator may also use a separator or stent retriever to crush or entangle the thrombus. [Explanation of symbols]

[0050] 50 catheter, 51 tip, 52 X-ray contrast marker, 53,54,55 Tube, 56 Strain relief, 57 Hub, 61 inner layer member, 61a inner peripheral surface, 62 outer layer member, 62a outer peripheral surface, 71 first reinforcing member, 72 second reinforcing member, 73 fiber, SA tip, SB middle, SC base

Claims

1. A catheter having a proximal portion, an intermediate portion, and a distal portion between a proximal end and a distal end, the catheter having an elongated lumen along a longitudinal axis, an inner layer member having an inner circumferential surface in contact with the lumen; an outer layer member having an outer peripheral surface of the catheter; a coil-shaped first reinforcing member provided outside the inner layer member between the inner circumferential surface and the outer circumferential surface; a blade-shaped second reinforcing member provided outside the first reinforcing member between the inner circumferential surface and the outer circumferential surface; A tip is provided at the distal end of the catheter, the tip being made of a flexible material that is gentle on blood vessels. and an X-ray contrast marker attached near the tip; The first reinforcing member is formed of a wire provided at a base end, an intermediate portion, and a tip end, A tip portion of the first reinforcing member is disposed adjacent to the X-ray contrast marker on a distal end side thereof, The second reinforcing member is provided in a region at a predetermined distance from the proximal end, and is omitted in the intermediate portion and the tip portion. catheter.

2. The catheter according to claim 1 , wherein the second reinforcing member is formed of a long member made of synthetic resin.

3. 3. The catheter according to claim 1, wherein the first reinforcing member is made of a metal wire.

4. The catheter according to any one of claims 1 to 3, wherein the second reinforcing member is composed of a bundle of multiple fibers.

5. The catheter according to any one of claims 1 to 4, wherein the cross-sectional shape of the first reinforcing member is rectangular.

6. The catheter according to any one of claims 1 to 4, wherein the cross-sectional shape of the first reinforcing member is circular.

7. The catheter according to any one of claims 1 to 4, wherein the cross-sectional shape of the tip portion of the first reinforcing member is circular.

8. A catheter according to any one of claims 1 to 7, a suction pump connected to the catheter.

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