Stents with wires, catheters, and catheter-stent systems

Abstract

The present invention provides a stent with a wire that further improves operability. The stent with a wire (10) comprises a wire (12) and a stent (11) connected at the distal side (D1) of the wire (12). The wire (12) forms a high-slidability portion in the area of ​​the distal side (D1). The stent with a wire (10) is inserted into a catheter having a structure in which a grid coil and a spiral coil are superimposed for use.

Description

Technical Field

[0001] The invention relates to a stent with a wire, a catheter and a catheter-stent system. Background Art

[0002] In the past, in order to capture thrombi generated in blood vessels, a catheter stent system (hereinafter referred to as a "CS system") having a thread and a stent connected to the distal end thereof was used. According to such a CS system, after the thrombus is captured by the stent inserted into the blood vessel, the thread is pulled out through the catheter to pull the thrombus out of the body together with the stent, thereby recovering the thrombus. As a catheter used in the CS system, a catheter having two types of coil structures superimposed is known (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent Application Publication No. 2016-185206.

[0006] Problem that the invention aims to solve

[0007] In the above-mentioned catheter, the flexibility of the top end is high and the torque transmission to the top end is excellent. However, in the above-mentioned catheter, since two kinds of coils are superimposed, the inner surface of the resin covering the coils is formed with concave and convex corresponding to the steps of the superimposed coils. On the other hand, the stent with a wire inserted into the catheter is connected to a coil-shaped member at the distal end of the wire. Since the metal wire is wound into a spiral shape, the coil-shaped member is formed with concave and convex on the outside.

[0008] When the stent with wires of the prior art is inserted into the above-mentioned catheter for use, the concavo-convex of the inner surface of the catheter and the concavo-convex of the coil-shaped member connected with the wires rub against each other, and the sliding resistance of the stent with wires in the catheter becomes larger. When the sliding resistance of the stent with wires in the catheter becomes larger, the operability of the doctor when pushing in and pulling out the wires becomes worse. Therefore, it is required to improve the operability of the stent with wires inserted into the catheter with concavo-convex inner surface. Summary of the invention

[0009] An object of the present invention is to provide a stent with a wire, a catheter, and a catheter-stent system that further improves operability.

[0010] Solutions for solving problems

[0011] The first invention relates to a stent with a wire, comprising a wire and a stent connected to the distal side of the wire, wherein the wire has a high sliding portion formed in the distal side region, and the stent with the wire is inserted into a catheter having a structure in which a grid coil and a spiral coil are superimposed and used.

[0012] The high slidability portion may be configured not to include a coil-shaped member.

[0013] The surface roughness Ra of the outer surface of the high sliding portion may be 0.5 nm or more and less than 2.0 nm.

[0014] The high sliding portion may be a solid layer made of a hydrophobic material.

[0015] The high sliding property portion may be a fluidized bed made of a hydrophilic material.

[0016] The above-mentioned stent may be used together with the above-mentioned catheter to reach the area after the M1 area in the skull.

[0017] The above-mentioned stent can be used to recover thrombus generated in cerebral blood vessels in the area after the M1 area.

[0018] The second invention relates to a catheter having a structure in which a grid coil and a spiral coil are superimposed, and a stent with a wire is inserted into the catheter and used. The stent with the wire has a wire that does not contain a coil-like component on the distal side and has a high-slidability portion, and a stent connected to the distal side of the wire.

[0019] The above-mentioned conduit may have irregularities on the inner surface.

[0020] The above-mentioned catheter can also reach the area after the M1 area in the skull and be used.

[0021] The third invention relates to a stent-catheter system having the above-mentioned stent with a wire and the above-mentioned catheter.

[0022] Effects of the Invention

[0023] According to the present invention, it is possible to provide a stent with a wire, a catheter, and a catheter-stent system that further improves operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 2 is a diagram showing the structure of the stent 10 with wires.

[0025] Figure 2 1 is a conceptual diagram showing the structure of the catheter stent system 1 .

[0026] Figure 3 2 is a conceptual diagram showing the structure of the mesh coil 211 and the helical coil 212 in the catheter 20 .

[0027] Figure 4 (A) to (E) are schematic diagrams showing the steps of removing a thrombus in a blood vessel using the catheter stent system 1 . DETAILED DESCRIPTION

[0028] The following is an explanation of the embodiments of the stent with a wire, the catheter, and the catheter stent system according to the present invention. In addition, the drawings added to this specification are schematic diagrams, and for the sake of easy understanding, the shapes, proportions, aspect ratios, etc. of each part are changed or exaggerated compared with the actual object. In addition, in the drawings, the section lines representing the cross-section of the component are appropriately omitted.

[0029] Figure 1 2 is a diagram showing the structure of the stent 10 with wires. Figure 2 1 is a conceptual diagram showing the structure of the catheter stent system 1 . Figure 3 2 is a conceptual diagram showing the structure of the mesh coil 211 and the helical coil 212 in the catheter 20 .

[0030] In the present specification, in the axial direction LD of the CS system (catheter stent system) 1 , the side farther from the doctor is referred to as the distal end side D1 , and the side closer to the doctor is referred to as the proximal end side D2 .

[0031] The CS system 1 of the present embodiment includes a stent 10 with a wire and a catheter 20 as described later.

[0032] like Figure 1 As shown, the stent with wires 10 has a stent 11 , a push wire 12 , and a cover layer (highly slidable portion) 13 as main structures.

[0033] The stent 11 is a part that captures the thrombus. The stent 11 is configured in a roughly cylindrical shape. The peripheral wall of the stent 11 is composed of a plurality of closed cells 11a surrounded by a filamentary material. In this specification, the peripheral wall of the stent 11 refers to the part that separates the inside of the cylinder of the roughly cylindrical structure of the stent 11 from the outside. The closed cell is also called an opening or a compartment, and refers to an opening portion surrounded by the filamentary material forming the mesh pattern of the stent 11. In addition, Figure 1 The bracket 11 is shown in an unloaded state. The unloaded state refers to a state in which the bracket 11 has no diameter reduction.

[0034] The stent 11 having the structure as described above is manufactured by laser processing a biocompatible material, for example, a tube formed of a superelastic alloy. In the case of manufacturing a superelastic alloy tube, in order to reduce costs, it is preferably manufactured by laser processing a tube of about 2 to 3 mm, expanding it to a desired diameter, and subjecting the tube to a shape memory treatment. In addition, the stent 11 is not limited to laser processing, and can also be manufactured by other methods such as cutting processing, or by braiding a metal wire formed into a filament into a cylindrical shape.

[0035] As the material of the bracket 11, it is preferred that the material itself has high rigidity and good biocompatibility. As such a material, for example, titanium, nickel, stainless steel, platinum, gold, silver, copper, iron, chromium, cobalt, aluminum, molybdenum, manganese, tantalum, tungsten, niobium, magnesium, calcium or alloys containing them can be cited. In addition, as such a material, synthetic resin materials such as polyolefins such as polyethylene (PE) and polypropylene (PP), polyamide, polyvinyl chloride, polyphenylene sulfide, polycarbonate, polyether, polymethyl methacrylate, etc. can also be used. Furthermore, as such a material, biodegradable resins (biodegradable polymers) such as polylactic acid (PLA), polyhydroxybutyric acid (PHB), polyglycolic acid (PGA), poly-ε-caprolactone can also be used.

[0036] Among them, titanium, nickel, stainless steel, platinum, gold, silver, copper, magnesium or alloys containing them are preferred. As alloys, for example Ni-Ti alloys, Cu-Mn alloys, Cu-Cd alloys, Co-Cr alloys, Cu-Al-Mn alloys, Au-Cd-Ag alloys, Ti-Al-V alloys, etc. can be cited. In addition, as alloys, alloys of magnesium and Zr, Y, Ti, Ta, Nd, Nb, Zn, Ca, Al, Li, Mn, etc. can be cited. Among these alloys, Ni-Ti alloys are preferred.

[0037] The end portion on the proximal end side D2 of the stent 11 is connected to the mark 14. The mark 14 is a member that serves as a mark for confirming the position of the end portion on the proximal end side D2 of the stent 11. The push wire 12 is connected to the proximal end side D2 of the mark 14.

[0038] The push wire 12 is operated by the doctor when moving the stent 11. The doctor pushes in and pulls out the push wire 12 through an operation unit (not shown) connected to the proximal end D2 of the push wire 12, thereby moving the stent 11 in the catheter 20 (described later) or in the blood vessel.

[0039] A covering layer 13 is formed in the area on the distal side D1 of the push wire 12. The covering layer 13 is used to improve the sliding property with the inner surface of the catheter 20 (described later). The covering layer 13 is formed to cover the outer surface of the area on the distal side D1 of the push wire 12. The area on the distal side D1 of the push wire 12 refers to, for example, a range of 50 to 3000 mm from the end of the distal side D1 of the push wire 12 in the direction toward the proximal side D2. The end of the distal side D1 of the covering layer 13 is bonded to the marker 14 via an adhesive (not shown). In addition, the end of the distal side D1 of the covering layer 13 is preferably as shown in FIG. Figure 1 As shown, there is seamless bonding with the mark 14, but there may be a gap of about several mm between the mark 14.

[0040] The covering layer 13 can be formed by a solid layer of a hydrophobic resin. As the solid layer of the hydrophobic resin, materials such as PTFE (polytetrafluoroethylene) and DLC (diamond-like carbon) can be used. Since these materials have low surface friction resistance (high sliding property), they can reduce the sliding resistance caused by mutual friction between the concave and convex surfaces formed on the inner surface of the catheter 20. In addition, the covering layer 13 can be formed in the region of the distal end side D1 of the above-mentioned push wire 12, and the length in the axial direction LD can be shorter or longer than the length of this region.

[0041] The covering layer 13 may also be formed of a fluidized layer of a hydrophilic resin. As the hydrophilic fluidized layer, materials such as hyaluronic acid and MPC polymers can be used. These materials are coated on the outer surface of the push wire 12 to form a semi-fixed layer with low surface friction resistance (high sliding property). Therefore, the sliding resistance generated by the mutual friction with the concave and convex formed on the inner surface of the catheter 20 can be reduced.

[0042] In the stent 10 with a wire of the present embodiment, the high sliding portion can be formed by a component whose surface roughness (arithmetic mean roughness) Ra of the outer surface is greater than 0.5nm and less than 2.0nm. In this embodiment, the high sliding portion can be formed by any material as long as it has physical properties that are safe for the human body. In addition, in the stent 10 with a wire of the present embodiment, a structure including a coil-shaped component between the distal side D1 of the push wire 12 and the stent 11 can also be adopted. In this case, on the outer surface of the coil-shaped component, a component that satisfies the above-mentioned surface roughness Ra condition is formed, so that the coil-shaped component can be configured as a high sliding portion. That is, if the stent with a wire involved in the present invention forms a high sliding portion in the distal side area of ​​the wire, a structure without a coil-shaped component can be adopted, and a structure containing a coil-shaped component can also be adopted.

[0043] In the stent with a wire 10 of this embodiment, a structure without forming the covering layer 13 may also be adopted. In this embodiment, the area on the distal side D1 of the push wire 12 becomes a high sliding portion. In addition, in the stent with a wire 10 of this embodiment, the high sliding portion does not contain a coil-shaped member.

[0044] like Figure 2 As shown in FIG. 1 , the CS system 1 of this embodiment includes the stent 11 and the catheter 20 configured as described above. The stent 11 is inserted into the catheter 20 in a state of reduced diameter. Figure 2 , a cross section of the stent 11 after the diameter reduction is schematically shown. Figure 2 In the CS system 1 shown, the push wire 12 is pushed out toward the distal end D1 when the stent 11 is delivered to the target site in the blood vessel, and is pulled out toward the proximal end D2 when the stent 11 is retrieved from the body.

[0045] In addition, if Figure 2 As shown in the enlarged area A of the conduit 20, the conduit 20 is composed of a core material 21 and a resin layer 22 covering the core material 21. Since the core material 21 has a structure in which a mesh coil 211 and a spiral coil 212 described later are superimposed, the inner surface 23 and the outer surface 24 of the conduit 20 have concavities and convexities corresponding to the steps of the two coils.

[0046] like Figure 3 As shown, the core material 21 is composed of a mesh coil 211 and a spiral coil 212. The mesh coil 211 is a portion in which metal wires are woven into a mesh shape. The mesh coil 211 is formed in the entire area of ​​the axial direction LD in the catheter 20. The spiral coil 212 is a portion in which metal wires are wound into a spiral shape on the outer peripheral side of the mesh coil 211.

[0047] like Figure 3 As shown, the catheter 20 of this embodiment is composed of an overlapping portion 21A and a mesh portion 21B, wherein the overlapping portion 21A is formed by overlapping a mesh coil 211 and a spiral coil 212, and the mesh portion 21B is composed only of the mesh coil 211. The mesh portion 21B is mainly formed in the area of ​​the distal end side D1 of the catheter 20. By forming the distal end side D1 of the catheter 20 only by the mesh coil 211, the flexibility of the top end portion (distal end side D1) of the catheter 20 can be improved. In addition, in the catheter 20, the entire area in the axial direction LD can also be formed by the overlapping portion 21A.

[0048] The outer diameter of the catheter 20 constructed as described above is, for example, 0.55 to 2.10 mm. The inner diameter is, for example, 0.33 to 1.78 mm. In the region where the mesh coil 211 and the spiral coil 212 overlap, the surface roughness (arithmetic mean roughness) Ra of the resin layer forming the inner surface is, for example, about 1 to 50 μm.

[0049] Next, an example of a method of using the stent catheter system 1 including the stent 11 according to the present embodiment will be described.

[0050] Figure 4 (A) to (E) are schematic diagrams showing the steps of removing a thrombus in a blood vessel using the stent catheter system 1. Figure 4 In (A) to (E) of FIG. 2 , in order to facilitate understanding of the deployed state of the stent 11 , the stent 11 and the push wire 12 in the catheter 20 are shown by solid lines.

[0051] First, if Figure 4As shown in (A), the catheter 20 is inserted into the patient's blood vessel BV to reach the position of the thrombus BC as the lesion site. The catheter 20 is sent until its tip reaches the distal end D1 of the thrombus BC. In addition, the catheter 20 may not penetrate the thrombus BC, for example, it may be inserted between the thrombus BC and the inner surface of the blood vessel BV.

[0052] Next, the stent 11 is inserted into the catheter 20 in a state where the diameter is reduced. Since the stent 11 has improved slidability, even when inserted into a relatively thin catheter, it can be pushed in with a lighter force than conventional stents.

[0053] Next, if Figure 4 As shown in (B), the push wire 12 is operated to push the stent 11 in a reduced diameter state along the inner lumen of the catheter 20. Then, the tip of the stent 11 is positioned at a position closer to the distal end side D1 than the thrombus BC.

[0054] Next, if Figure 4 As shown in (C), the stent 11 is pushed out from the top of the catheter 20 at the location of the thrombus BC and deployed. Figure 4 The position shown in (B) is pulled out toward the proximal end side D2, and the stent 11 is relatively pushed out from the catheter 20 and deployed. The entire stent 11 is pushed out from the catheter 20.

[0055] Next, if Figure 4 As shown in (D), the catheter 20 and the push wire 12 are pulled out toward the proximal end D2. Figure 4 As shown in (E), the stent 11 that has captured the thrombus BC can be pulled out from the body.

[0056] By operating the CS system 1 according to the above steps, the thrombus BC can be recovered from the body. Figure 4 (A) to (E) are diagrams showing an overview of the work of recovering the blood clot BC. The work of actually recovering the blood clot BC from the body includes various steps depending on the lesion site and the like.

[0057] According to the CS system 1 of the above embodiment, since the cover layer 13 with high sliding property is formed between the distal end side D1 of the push wire 12 and the marker 14, the sliding resistance generated by the friction with the concave and convex formed on the inner surface of the catheter 20 can be further reduced. As a result, the doctor can push in and pull out the push wire 12 with less force, so the operability of the CS system 1 can be further improved.

[0058] In addition, the CS system 1 of the embodiment is mainly used to recover thrombi generated in cerebral blood vessels, but there are many small and curved blood vessel inner diameters in the area after the M1 area of ​​the skull. In such areas, since the inner diameter of the catheter used is also reduced, the sliding resistance in the catheter is large in the stent with a wire in the prior art, and the operability is poor. In contrast, according to the CS system 1 of this embodiment, since the sliding resistance of the stent with a wire in the catheter can be further reduced, excellent operability can be obtained even in the area after the M1 area of ​​the skull.

[0059] Next, the test results of the slidability of the stent with a wire according to the present invention will be described.

[0060] As Examples 1 to 3, three types of stents with high sliding properties were produced. Among them, in the stent with silk thread of Example 1, a PTFE layer (solid layer) with a thickness of 0.05 mm and a length of 250 mm was formed on the outer surface of the distal side D1 of the push wire 12 as a high sliding portion. In the stent with silk thread of Example 2, a resin layer (flowing layer) of hyaluronic acid with a thickness of 0.001 mm and a length of 250 mm was coated on the outer surface of the distal side D1 of the push wire 12 as a high sliding portion. In the stent with silk thread of Example 3, the stent is connected without adding a coil-shaped member on the distal side D1 of the push wire. In Example 3, the area on the distal side D1 of the push wire becomes the high sliding portion. In addition, as an example of the prior art, a stent with silk thread having a coil-shaped member between the distal side D1 of the push wire and the stent was produced. The example of the prior art is an existing product that is generally widely used. For these four stents with silk threads, the tensile load was measured under the following measurement conditions.

[0061] Equipment used: Catheter:

[0062] A catheter having a surface roughness (arithmetic mean roughness) Ra of 1.5 nm for a resin layer formed by overlapping a mesh coil and a spiral coil as a core material and forming an inner surface

[0063] Digital force gauge (push-pull pressure gauge)

[0064] Pull-out device

[0065] Constant temperature bath

[0066] thermometer

[0067] Test conditions:

[0068] Speed: 60mm / min

[0069] Stretching distance: effective length of bracket + 10mm

[0070] Test temperature: 37±2℃

[0071] Test method:

[0072] (1) Use a thermometer to confirm that the temperature of the thermostatic bath is 37±2℃.

[0073] (2) A catheter is set in a constant temperature bath.

[0074] In addition, the catheter was assumed to be S-shaped consisting of arcs with a radius of 5 mm, in anticipation that the catheter would actually pass through a curved part in the body.

[0075] (3) Insert the stent with the silk thread from the hand side of the catheter until the tip of the stent is located further distal than the place where the catheter is bent into an S shape.

[0076] (4) Connect the digital force gauge installed on the pulling device to the hand side of the bracket with the wire.

[0077] (5) When the catheter and the stent with the thread are in an S-shape, the stent with the thread is pulled toward the hand side at a predetermined speed by a pulling device.

[0078] (6) When the stent with the silk thread is stretched to an effective length of +10 mm, the maximum and minimum values ​​of the tensile load measured by the digital dynamometer are recorded.

[0079] For the stents with silk threads of Examples 1 to 3 and Comparative Examples, the above test was repeated several times and the values ​​were measured. Moreover, the average value of the tensile load less than 1N was recorded as "0", 1N or more and less than 3N was recorded as "△", and 3N or more was recorded as "×". Among them, the evaluation of "×" was recorded as poor (NG: Not Good), and the evaluation of "△" and "0" was recorded as good (OK). In addition, "△" means: it is a good level in actual use, but slightly lower than the evaluation of "0".

[0080] Table 1 shows the evaluation results of the above-mentioned tests for each of the stents with wires of Examples 1 to 3 and Comparative Example.

[0081] [Table 1]

[0082]

[0083] As shown in Table 1, the average tensile load of the stents with filaments of Examples 1 to 3 was less than 1 N, and was evaluated as “0”. In addition, the average tensile load of the stents with filaments of Comparative Example was 3 N or more, and was evaluated as “×”.

[0084] The above results show that the stents with wires of Examples 1 to 3 are all excellent in operability. In particular, it can be seen that the average tensile load of Example 1 in which a PTFE layer is formed on the outer surface of the distal end D1 of the push wire 12 and Example 2 in which a hyaluronic acid resin layer is formed is 0.7N or less, and the operability is even better.

[0085] In addition to the above test, a sensory test was conducted for each stent with a thread in Examples 1 to 3 and the comparative example: the stent with a thread was inserted into the same S-shaped catheter as in the above test, and 20 subjects were asked to repeatedly push and pull the push thread several times to evaluate the operability. As a result, all the stents with a thread in Examples 1 to 3 were evaluated by the subjects as having improved operability. On the other hand, no subject evaluated the stent with a thread in the comparative example as having improved operability.

[0086] Although the embodiments of the present disclosure are described above, the present disclosure is not limited to the above-mentioned embodiments, and various deformations and changes can be made as described in the following deformation modes, and those are also included in the technical scope of the present disclosure. In addition, the effects described in the embodiments only list the most preferred effects achieved by the present disclosure, and are not limited to the effects described in the embodiments. In addition, the above-mentioned embodiments and the deformation modes described in the following can be used in appropriate combinations, but detailed descriptions are omitted.

[0087] (Deformation method)

[0088] In the stent 10 with a wire of the embodiment, a coil-shaped member may be provided between the distal end D1 of the push wire 12 and the stent 11, and a covering layer 13 may be formed on the outer surface of the coil-shaped member (see Figure 1 According to this embodiment, the entirety of the coil-shaped member and the cover layer 13 can be configured as a high-slidability portion. In this embodiment, the cover layer 13 can be formed of a solid layer of a hydrophobic resin or a fluidized layer of a hydrophilic resin.

[0089] In the embodiment, although the example of connecting the retractable stent 11 to the stent 10 with the wire is described, the stent connected to the stent 10 with the wire may also be a retention type. In this case, for example, the outside of the contracted balloon is surrounded by the stent after the diameter is reduced, and the balloon is inflated at the lesion site to open the blood vessel and expand the stent. Then, the balloon is deflated and the balloon is recovered together with the push wire, so that only the stent can be retained at the lesion site.

[0090] In the embodiment, the surface roughness Ra of the outer surface of the high sliding part (for example, the cover layer 13) is described as 0.5 nm or more and less than 2.0 nm. However, the outer surface of the high sliding part may be set to an average height Zc of 10 to 100 μm as specified in JIS B 0601, for example.

[0091] In the embodiment, an example of forming the covering layer 13 by a solid layer of a hydrophobic resin is described, and it is also described that the covering layer 13 can also be formed by a fluidized layer of a hydrophilic resin. Not limited to this, the covering layer 13 can also be formed by a solid layer made of a hydrophobic material. As a solid layer made of a hydrophobic material, DLC (diamond-like carbon) can be cited, for example. In addition, the covering layer 13 can also be formed by a fluidized layer made of a hydrophilic material. As a fluidized layer made of a hydrophilic material, silicone can be cited, for example.

[0092] Description of Reference Numerals

[0093] 1: Catheter stent system

[0094] 10: Bracket with silk thread

[0095] 11: Bracket

[0096] 12: Pushing

[0097] 13: Overlay

[0098] 20: Catheter

[0099] 21: Core material

[0100] 211: Grid coil

[0101] 212: Helical coil

Claims

1. A stent with a wire, comprising: A silk thread and a stent attached to the distal end of the silk thread, The wire has a high sliding portion formed in a distal end region, and the surface roughness Ra of the outer surface of the high sliding portion is greater than or equal to 0.5 nm and less than 2.0 nm. The stent with the wire is inserted into a catheter having a structure in which a grid coil and a spiral coil are superimposed.

2. The stent with wires according to claim 1, wherein: The high slidability portion does not include a coil-shaped member.

3. The stent with wires according to claim 1, wherein: The high-slidability portion is made of a solid layer made of a hydrophobic material.

4. The stent with wires according to claim 1, wherein: The high-slidability portion is made of a fluidized layer made of a hydrophilic material.

5. The stent with wires according to any one of claims 1 to 4, wherein: The stent is used after reaching the M1 region in the skull together with the catheter.

6. The stent with wires according to claim 5, wherein: The stent is used in the area after the M1 area to recover thrombus generated in the cerebral blood vessels.

7. A stent catheter system, comprising a stent with a wire according to any one of claims 1 to 6, and a catheter having a structure in which a grid coil and a spiral coil are superimposed, The conduit has concavities and convexities on the inner surface, The catheter is used after reaching the M1 region within the skull.

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