Balloon catheter

Abstract

[Problem] To provide a balloon catheter with which it is possible for a balloon to be reliably secured, independently, in a target position without blocking the flow of blood. This balloon catheter has: a flexible outer cylinder shaft; a flexible inner cylinder shaft inserted through the outer cylinder shaft; a balloon that is secured to the outer cylinder shaft and that expands or contracts in the transverse direction due to pressure of an internal fluid fed via a space in the outer cylinder shaft; and a securing member that is disposed on the outer circumferential side of the balloon and that and that increases or decreases in diameter in the transverse direction, independently of the balloon, due to mutual movement of the outer cylinder shaft and the inner cylinder shaft in the longitudinal direction. The distal end part of the inner cylinder shaft and the distal end part of the securing member are secured to each other, the distal end part of the outer cylinder shaft and the rear end part of the securing member are secured to each other, and the securing member has a gap through which an external fluid can pass when the diameter is increased.

Description

Balloon catheter

[0001] The present invention relates to a balloon catheter used in the medical field.

[0002] Medical balloon catheters generally have a shaft with a balloon at its tip, and treatments are minimally invasively performed by expanding the balloon. Specific therapeutic applications include arrhythmia treatment, embolic material removal, angioplasty, and balloon aortic valvuloplasty.

[0003] In angioplasty and balloon aortic valvuloplasty, the balloon of the balloon catheter itself can be used to expand a stenotic body lumen, or to deliver an expandable endoprosthesis such as a stent into the body lumen and then expand the balloon to deploy the endoprosthesis.

[0004] Furthermore, when a surgically implanted prosthetic valve deteriorates and a new prosthetic valve is placed via a catheter, the valve orifice area may become narrower. To expand the valve orifice area, a treatment can be performed in which the frame of the surgically implanted prosthetic valve is crushed by expansion using a balloon catheter.

[0005] For example, a pressure of 2-3 atm or more is required to treat a narrowed portion of the aortic valve (aortic stenosis), and a pressure of 7 atm or more is required for the balloon to expand and place a stent. Furthermore, a pressure of 15 atm or more is required to fracture the frame of a surgically implanted artificial valve.

[0006] In a surgical technique for using a balloon catheter to expand a lesion or an organ such as a blood vessel, in order to achieve both flexibility that can follow the curvature of a biological lumen and strength sufficient for the expansion, a balloon catheter has been reported in which a tubular mesh-like reinforcing member is placed between the inner and outer layers of a balloon having two layers, an inner layer and an outer layer, and the reinforcing member is fixed only at the ends of the inner and outer layers, with the middle portion not being directly fixed (Patent Document 1).

[0007] Furthermore, in a surgical technique for delivering and deploying an expandable internal prosthesis, such as an artificial valve or a stent, to a target site within a body lumen, a balloon catheter has been reported that includes an adjustment device for adjusting the position of the balloon relative to a crimped artificial valve, allowing a physician to precisely control the positioning of the artificial valve at the intended implantation site (Patent Document 2).

[0008] Furthermore, a technique has been reported in which artificial valves are crushed using a balloon with improved pressure resistance due to the inclusion of high-strength fibers in a spiral pattern inside (Non-Patent Document 1).

[0009] In addition, there is a procedure in which a stentreaver deployed by self-expansion engages with and removes the internal blood clot to remove a blood clot, thrombus, blockage, or obstruction that is obstructing blood flow in an artery. An intravascular device has been reported in which, after removing the blood clot, the self-expanding stentreaver is further expanded with a semi-compliant balloon and then detached from the shaft to leave it in place (Patent Document 3).

[0010] JP 2016-052447 A JP 2020-062399 A JP 2021-013743 A

[0011] John T. Saxon et al., "Bioprosthetic Valve Fracture During Valve-in-Valve TAVR: Bench to Bedside," Interventional Cardiology Review, Vol. 13, No. 1, January 2018, pp. 20-26

[0012] The catheter described in Patent Document 1 is equipped with a tubular mesh member (e.g., a high-strength fiber with a tensile breaking strength of 2 GPa or more and an elastic modulus of 50 GPa or more) that forms an intermediate layer between the inner and outer layers of the balloon in order to improve pressure resistance. However, when it is desired to inflate the balloon at a desired position, the inner, intermediate, and outer layers of the balloon are integrated, so that when the balloon is inflated at the desired position, the balloon is swept away by the blood flow and may become displaced. Furthermore, because the position of the balloon is displaced during inflation, it is necessary to inflate the balloon multiple times to reposition it, which blocks the blood flow each time.

[0013] Furthermore, with regard to the catheter described in Patent Document 2, when the balloon is inflated at the target position, the balloon may slip due to blood flow, causing it to shift out of position or deviate from the target position. If such a shift in position occurs, it becomes necessary to deflate the balloon again and then perform the same procedure, which increases the time required for the surgery.

[0014] Furthermore, the catheter of Non-Patent Document 1 also has the problem that when the balloon is inflated at the target position, it is swept away by the blood flow and shifts out of position. Furthermore, because the balloon shifts from the target position during inflation, multiple inflations are required, which can lead to the balloon being inflated incorrectly at the artificial valve cusp or left ventricular outflow tract, resulting in symptoms such as artificial valve dysfunction and atrioventricular block.

[0015] Furthermore, the intravascular device of Patent Document 3 has a problem in that the stentriever and the shaft are detachable, making it difficult to use in procedures requiring high pressure. Furthermore, since the stentriever is self-expanding, it must be used in combination with a component such as a microcatheter for delivery into the blood vessel.

[0016] Therefore, an object of the present invention is to provide a balloon catheter that can reliably fix the balloon at a desired position by itself without blocking the flow of blood.

[0017] The present inventors conducted extensive research to solve the above problems and discovered the following inventions (1) to (7): (1) A balloon catheter comprising: a flexible outer cylindrical shaft; a flexible inner cylindrical shaft inserted into the outer cylindrical shaft; a balloon fixed to the outer cylindrical shaft and expanding or contracting in the transverse direction due to the pressure of an internal fluid supplied through a space within the outer cylindrical shaft; and a fixing member disposed on the outer circumferential side of the balloon and expanding or contracting in the transverse direction independently of the balloon as the outer cylindrical shaft and the inner cylindrical shaft move relative to each other in the longitudinal direction, wherein a distal end of the inner cylindrical shaft and a distal end of the fixing member are fixed to each other, and a distal end of the outer cylindrical shaft and a proximal end of the fixing member are fixed to each other, and the fixing member has a gap that allows the passage of an external fluid when expanded in diameter. (2) A balloon catheter according to (1), wherein the fixing member is made of a wire material, and the wire material has any of a braided, woven, spiral, and linear shape. (3) The balloon catheter according to (1) or (2), wherein the wire has a Young's modulus of 60 to 500 GPa and a tensile strength of 500 MPa or more. (4) The balloon catheter according to any one of (1) to (3), wherein the inner cylindrical shaft has a large-diameter portion provided at a distal end of the inner cylindrical shaft and a small-diameter portion provided at a proximal end of the inner cylindrical shaft and having an inner diameter smaller than that of the large-diameter portion, the balloon is fixed to the small-diameter portion of the inner cylindrical shaft, and the fixing member is directly fixed to the large-diameter portion of the inner cylindrical shaft. (5) The cross-sectional area of ​​the wire is 0.0019 mm ２ (6) The balloon catheter according to any one of (1) to (4), wherein the balloon is made of one or more layers including a layer of an elastic material, and is used for treating aortic valve stenosis. ２ (7) The balloon catheter according to any one of (1) to (4), wherein the balloon is made of two or more layers including a layer of elastic material and a layer of braided resin fiber, and is used for expanding a stent. ２ The balloon catheter according to any one of (1) to (4), wherein the balloon is made of three or more layers including a layer of elastic material and a braided layer of resin fiber, and is for crushing artificial valves.

[0018] According to the present invention, a fixing member with a gap is disposed on the outside of the balloon so as not to block external fluids such as blood flow, which will be described later, and the fixing member and balloon can be expanded and contracted independently. Therefore, by moving the inner cylindrical shaft in the longitudinal direction, the diameter of only the fixing member can be expanded, and the balloon can be fixed to the lumen without blocking external fluids, and then treatment can be performed by expanding the balloon. This reduces the impact of blood flow blockage and reduces balloon displacement. Furthermore, if the fixing member is rigid, a wide range of procedures can be performed, from procedures requiring high pressure resistance, such as artificial valve fragmentation, which was previously difficult, to aortic valve dilation, which only requires low pressure resistance.

[0019] FIG. 1 is a cross-sectional view of a balloon catheter according to a first embodiment of the present invention when the fixing member is expanded in diameter and the balloon is expanded. FIG. 2 is a cross-sectional view of a balloon catheter according to a first embodiment of the present invention when the fixing member is contracted in diameter and the balloon is deflated. FIG. 3 is a cross-sectional view of a balloon catheter according to a first embodiment of the present invention when the fixing member is expanded in diameter and the balloon is deflated. FIG. 4 is a diagram showing an example of a treatment method using the first embodiment of the present invention. FIG. 5 is a cross-sectional view of the vicinity of the balloon of a balloon catheter according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view of the vicinity of the balloon of a balloon catheter according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view of the vicinity of the balloon of a balloon catheter according to a fourth embodiment of the present invention.

[0020] The balloon catheter of the present invention comprises a flexible outer cylindrical shaft, a flexible inner cylindrical shaft inserted into the outer cylindrical shaft, a balloon fixed to the outer cylindrical shaft and expanded or contracted in the transverse direction by the pressure of an internal fluid supplied through a space within the outer cylindrical shaft, and a fixing member disposed on the outer periphery of the balloon and expanded or contracted in the transverse direction independently of the balloon as the outer cylindrical shaft and the inner cylindrical shaft move relative to each other in the longitudinal direction, wherein the distal end of the inner cylindrical shaft and the distal end of the fixing member are fixed to each other, and the distal end of the outer cylindrical shaft and the rear end of the fixing member are fixed to each other, and the fixing member has a gap which allows the passage of an external fluid when expanded in diameter.

[0021] The present invention will be described in detail below with reference to embodiments.

[0022] In this specification, the term "distal end" refers to the longitudinal end of the balloon catheter as seen by the surgeon, and the term "proximal end" refers to the longitudinal end of the balloon catheter as seen by the surgeon. Furthermore, the term "fixed" refers to two components being fixed together, and unless otherwise specified, they may be fixed together via another component.

[0023] "Internal fluid" refers to a fluid flowing inside the balloon, such as a liquid like water or saline, or a gas like nitrogen gas. "External fluid" refers to a fluid flowing outside the balloon, such as blood flowing outside the balloon when the catheter enters a blood vessel during a balloon catheterization procedure. "Expansion pressure" refers to the internal pressure generated in the lumen of the balloon when an internal fluid is injected into the balloon. "Non-elastic material" refers to a material with low elasticity, i.e., a modulus of elasticity (Young's modulus) at room temperature (test method: ISO 6892-1) of approximately 10 GPa or more.

[0024] 1 is a cross-sectional view of a balloon catheter 10 according to a first embodiment of the present invention, showing the state in which the fixing member is expanded and the balloon is inflated. The balloon catheter 10 shown in FIG. 1 is formed of a fixing member 100, a balloon 101, an outer cylindrical shaft 102, and an inner cylindrical shaft 103.

[0025] <Fixing Member> In the present invention, the fixing member 100 of the balloon catheter 10 is fixed to the distal end of the inner cylindrical shaft 103 (described later) and to the proximal end of the outer cylindrical shaft 102, and is disposed on the outer periphery of the balloon 101. Therefore, relative longitudinal movement of the outer cylindrical shaft 102 and the inner cylindrical shaft 103 changes the structure of the balloon catheter 10 from the cross-sectional view of FIG. 2 , in which the fixing member 100 is contracted and the balloon 101 is deflated, to the cross-sectional view of FIG. 3 , in which the fixing member 100 is expanded and the balloon 101 is deflated. This allows the diameter of the fixing member 100 to be expanded or contracted in the transverse direction independently of the balloon 101 without using an internal fluid. In other words, the balloon catheter 10 itself can be fixed to a body cavity simply by moving the inner cylindrical shaft 103 at a desired position within the body cavity. For example, a stricture occurring in a body cavity can be treated with the balloon catheter 10 by the procedure (procedures (1) to (4)) of the treatment method using the balloon catheter according to the first embodiment shown in Figure 4. Furthermore, because the fixing member 100 has gaps that allow external fluid to pass through when the diameter is expanded, the balloon catheter 10 itself can be fixed to the body cavity without blocking the external fluid flowing into the body cavity, even when the diameter is expanded.

[0026] The fixing member 100 is preferably made of wire material, as long as it has high rigidity and has gaps that do not block external fluids. Specific structures of the wire material include a braided shape formed by knotting or intertwining linear resin fiber, metal wire, or other wire material and braiding them in a staggered pattern (crossing them alternately), a woven shape formed by weaving linear fiber, metal wire, or other material, a spiral shape formed by winding a single or multiple fiber material in a spiral, or a linear shape formed by arranging a single or multiple fiber material in parallel to the axial direction of the balloon 101, and a combination of any of these shapes may also be used.

[0027] Furthermore, the braided and woven shapes can be obtained, for example, by braiding, knitting, weaving, etc., multiple wires made of inelastic materials. Here, braiding broadly means combining wires together to maintain a shape, and knitting refers to the process of creating a cloth-like structure by knotting or intertwining wires together and braiding them in a staggered pattern (crossing them alternately). Furthermore, weaving refers to the process of creating a cloth-like structure (woven fabric structure) by crossing wires that serve as warp threads and wires that serve as weft threads according to a certain rule. Furthermore, the gaps that do not block external fluids are, for example, 0.002 mm when the external fluid is blood. ２ It is preferable that this is equal to or greater than this.

[0028] The material of the fixing member 100 is not particularly limited, but preferably has a Young's modulus (test method: ISO6892-1) of 60 GPa to 500 GPa and a tensile strength of 500 MPa or more, and more preferably has a Young's modulus of 100 GPa to 500 GPa and a tensile strength of 500 MPa or more. ２ It is preferable that the thickness is 0.0063 mm or more. ２ It is preferable that the material is one of the following. It is also preferable that the material is radiopaque. For example, carbon or metals approved for medical use can be used. Metals include simple metals such as aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, niobium, molybdenum, rhodium, palladium, tantalum, tungsten, rhenium, platinum, and gold, as well as alloys containing two or more metals such as stainless steel. From the viewpoints of workability and economy, it is preferable to use stainless steel, and from the viewpoint of Young's modulus, it is preferable to use tungsten or a cobalt-chromium alloy (such as cobalt-chromium-molybdenum), and from the viewpoint of shape memory, nickel-titanium is preferable.

[0029] The fixing member 100 is not particularly limited as long as it achieves the expansion pressure required for the treatment method. For example, when used for the treatment of aortic valve stenosis, the required expansion pressure is 2 to 3 atm or more, so the cross-sectional area is 0.0019 mm ２In the case of stent placement, the required expansion pressure is 7 atm or more, so 0.0038 mm ２ In the case of artificial valve crushing applications, the required expansion pressure is 15 atm or more, so a cross-sectional area of ​​0.0063 mm ２ The above cross-sectional area is preferred.

[0030] The cross-sectional shape of the fixing member 100 is not particularly limited, but is preferably circular from the viewpoint of workability, and rectangular from the viewpoint of ease of bending and friction of the fixing member.

[0031] <Balloon> The balloon 101 has a structure that allows it to expand or contract in the transverse direction due to the pressure of an internal fluid supplied via a space within the outer cylindrical shaft 102 (described later). The structure of the balloon 101 is preferably formed of one layer or two or more layers, as shown in the cross-sectional view of the balloon catheter of the first embodiment in Figure 1 and the cross-sectional view of the balloon catheter of the second embodiment in Figure 5.

[0032] Furthermore, if the balloon 101 has one layer, it is preferable that it is made only of a layer of elastic material 107. If it has two layers, it is preferable that the inner layer forming the inner surface is made of a layer of elastic material 107. If it has three or more layers, it is preferable that the surface layer forming the outer surface and the inner layer forming the inner surface are made of a layer of elastic material 107. The elastic material 107 is not particularly limited, but may be a general rubber elastic material. For example, a rubber elastic material having a hardness JIS-A of 15 to 80 is preferable. Specific examples include natural rubber (latex), silicone elastomer, thermoplastic elastomer, isobutylene or polybutadiene rubber, polytetrafluoroethylene, fluorosilicone rubber, chlorinated polyethylene elastomer, ethylene vinyl acetate, hexafluoropropylene-vinylidene fluoride-tetrafluoroethylene copolymer (e.g., trade names Fluorel (registered trademark) and Viton (registered trademark)), butyl rubber, synthetic polyisoprene rubber, styrene-butadiene rubber, tetrafluoroethylene propylene copolymer, thermoplastic copolyester, polyurethane, etc. Different materials may be selected for different portions of the balloon wall or for different layers of the balloon, or two or more materials may be mixed to adjust the modulus of elasticity according to the intended use. From the viewpoints of processability and economy, natural rubber (latex) is preferred, while polyurethane is preferred from the viewpoints of pressure resistance and economy.

[0033] Natural rubber means rubber that is naturally produced, and is usually obtained as natural rubber latex, which is an emulsion of natural rubber particles dispersed in a medium such as water.

[0034] As long as the effects of the present invention are not impaired, a braided layer 106 made of resin fibers may be included as a surface layer of the balloon 101 if the balloon 101 has two layers, or as an intermediate layer inside the balloon 101 if the balloon 101 has three or more layers. The material of the resin fibers is not particularly limited, but may be any material commonly used for resin fibers, such as polyurethane, polyolefins such as polyethylene or polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate, polyamides such as nylon 6 and nylon 12, polyvinyl chloride, ethylene-vinyl acetate copolymers or saponified products thereof, polystyrene, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide, aromatic polyamides, polyimides, polyamideimides, cellulose, cellulose acetate, polyvinylidene chloride, polyacrylonitrile, polyvinyl alcohol, and copolymers thereof. In particular, polyesters and polyurethanes are preferred from the viewpoints of biocompatibility and elastic modulus.

[0035] The cross-sectional shape of the resin fiber is not particularly limited, and various cross-sectional shapes can be appropriately selected depending on the application and required properties. Specifically, the cross-section may be a perfect circular cross-section, or a non-perfect circular cross-section. Specific examples of non-perfect circular cross-sections include, but are not limited to, multi-lobed, polygonal, flat, elliptical, C-shaped, H-shaped, S-shaped, T-shaped, W-shaped, X-shaped, Y-shaped, square-shaped, and hollow. Furthermore, multiple types of cross-sectional shapes may be employed.

[0036] When resin fibers are used as composite false-twist yarns, the weight ratio of the resin fiber core yarn to the resin fiber sheath yarn is not particularly limited. For example, when a composite false-twist yarn of urethane fiber and polyester fiber is used, if the weight of the urethane fiber is in the range of 30 to 70% by weight, assuming the total weight to be 100% by weight, sufficient extensibility can be obtained, and the polyester fiber sheath yarn can sufficiently cover the periphery of the core yarn, which is expected to result in improved abrasion resistance, etc. The degree of entanglement of the composite false-twist yarn is not particularly limited, but is preferably 50 to 150. An entanglement degree of 50 or more suppresses separation of the core yarn and the sheath yarn. Furthermore, a degree of 150 or less is preferable because it does not reduce the stretch recovery rate.

[0037] The braided layer 106 may be knitted by any method, such as warp knitting, weft knitting, or flat knitting, as long as it has elasticity and pressure resistance. Weft knitting is preferred.

[0038] The method for joining the braided layer 106 and the elastic material 107 is not particularly limited, and may include lamination using an adhesive, thermocompression bonding, kneading, extrusion molding, resin impregnation, coating, etc. For example, a balloon may be obtained by bonding the braided layer 106, which is formed by braiding a false twisted yarn made of polyurethane and polyester into a cylindrical shape, to natural rubber with rubber cement.

[0039] Various additives may be contained in an amount of 30% by mass or less relative to 100% by mass of the elastic material 107, provided that the effects of the present invention are not impaired. Examples of such additives include X-ray contrast agents, colorants, antioxidants, thermal stabilizers, and lubricants. The lower limit of the additive content is not particularly limited, and even 0% by mass is acceptable relative to 100% by mass of the elastic material. Furthermore, inorganic or organic particles may be contained in an amount of 20% by mass or less relative to 100% by mass of the elastic material 107, provided that the performance of the present invention is not impaired. Examples include calcium carbonate, titanium oxide, silicon oxide, calcium fluoride, lithium fluoride, alumina, barium sulfate, zirconia, calcium phosphate, cross-linked polystyrene particles, and metal nanoparticles. The lower limit of the inorganic or organic particle content is not particularly limited, and even 0% by mass is acceptable relative to 100% by mass of the elastic material 107.

[0040] Furthermore, the balloon 101 is not particularly limited as long as it achieves the inflation pressure required for the treatment method; for example, when used to treat aortic valve stenosis, the required inflation pressure is 2 to 3 atm or more, so a balloon consisting of one or more layers including a layer of elastic material 107 is preferred; when used to place a stent, the required inflation pressure is 7 atm or more, so a balloon consisting of two or more layers including a layer of elastic material 107 as an inner layer and a braided layer 106 as a surface layer is preferred; and when used to crush an artificial valve, the required inflation pressure is 15 atm or more, so a balloon consisting of three or more layers including a layer of elastic material 107 as a surface layer, a braided layer 106 of resin fiber as an intermediate layer, and a layer of elastic material 107 as an inner layer is preferred.

[0041] <Outer cylindrical shaft> The inner cylindrical shaft 103 is inserted into the lumen of the outer cylindrical shaft 102, and a guide wire is passed through the lumen of the inner cylindrical shaft 103, and the inner cylindrical shaft 103 and the outer cylindrical shaft 102 are fed into the body along the guide wire.

[0042] The outer cylindrical shaft 102 may be any flexible tubular shape, and is preferably formed, for example, from a single-layer tube or a multi-layer tube having two or more layers, and is preferably formed from a multi-layer tube consisting of three layers: an outer layer, an intermediate layer, and an inner layer.

[0043] When the outer cylindrical shaft 102 is made of a single-layer tube, the material used for the outer cylindrical shaft 102 is preferably formed from a polymeric material with excellent antithrombotic properties, since it comes into contact with biological tissue. Examples of such a polymeric material include vinyl chloride, polyurethane, polyamide, polyether block amide copolymer, polypropylene, polyolefin, and polyethylene terephthalate. In order to enable thermal welding to the balloon, it is preferable that the material be polyurethane or polyether block amide copolymer that matches the material of the balloon 101.

[0044] When the outer cylindrical shaft 102 is a multilayer tube, the outer layer of the outer cylindrical shaft 102 is preferably formed from a polymeric material with excellent antithrombotic properties, since it comes into contact with biological tissue. Examples of such polymeric materials include vinyl chloride, polyurethane, polyamide, polyether block amide copolymer, polypropylene, polyolefin, and polyethylene terephthalate. To enable thermal welding to the balloon 101, polyurethane or polyether block amide copolymer that matches the material of the balloon 101 is preferred.

[0045] When the outer cylindrical shaft 102 is a multi-layer tube, the middle layer of the outer cylindrical shaft 102 preferably contains a metal flat wire or the like because durability and stiffness are required. As the metal, for example, stainless steel, which is commonly used in medical devices, is preferably used.

[0046] When the outer tubular shaft 102 is a multi-layer tube, the inner layer of the outer tubular shaft 102 is required to be easily slippery, and the tube as a whole is preferably formed from a polymeric material that is stretch-resistant. As the polymeric material, a fluorine-based polymer such as PTFE or a polyether block amide copolymer containing barium is preferably used. Furthermore, from the viewpoint of adhesiveness, a polyether block amide copolymer containing barium is preferably used.

[0047] In forming the multilayer tube, the materials used to satisfy the properties required for the outer layer, inner layer, and the entire tube are not particularly limited, and the multilayer tube can be obtained by laminating using an adhesive, thermocompression bonding, multilayer molding by coextrusion, kneading and extrusion molding, resin impregnation, surface coating, etc.

[0048] <Inner Cylindrical Shaft> The inner cylindrical shaft 103 may also be any flexible tubular shape, and may be formed, for example, from a single-layer tube or a multi-layer tube having two or more layers. From the viewpoint of preventing buckling of the guide wire inside the inner cylindrical shaft 103, it is preferable to adjust the bending rigidity according to the intended use, such as by using a two-layer tube in which a hard material and a soft material are laminated.

[0049] When the inner cylindrical shaft 103 is a single-layer tube made of only a layer of a polymer material, examples of the polymer material include, but are not limited to, polyamide, polyether block amide, polyimide, polyether ether ketone, polyphenylene sulfide, polyetherimide, and polyamideimide. From the viewpoint of flexibility, polyamide or polyether block amide is preferred, and from the viewpoint of rigidity, polyether ether ketone is more preferred.

[0050] The mechanical properties of the inner cylindrical shaft 103 (test method: ISO 527) are preferably a tensile modulus of 500 to 1400 MPa, and a yield strength of 25 MPa or more. If the tensile modulus is 500 MPa or more, the inner cylindrical shaft 103 is less likely to deform when the balloon 101 is stretched, and if it is 1400 MPa or less, it can easily pass through curved portions such as the aortic arch. Similarly, if the yield strength is 25 MPa or more, it can easily pass through curved portions such as the aortic arch. The wall thickness of the inner cylindrical shaft 103 is preferably 0.1 mm to 0.23 mm.

[0051] 6 , the inner cylindrical shaft 103 may include a large-diameter portion 109 at the distal end of the inner cylindrical shaft 103, a small-diameter portion at the proximal end of the inner cylindrical shaft 103, the small-diameter portion having an inner diameter smaller than the large-diameter portion 109, and a tapered portion connecting the large-diameter portion and the small-diameter portion. The balloon 101 may be fixed to the small-diameter portion, and the fixing member 100 may be directly fixed to the large-diameter portion. Here, it is preferable that the balloon 101 be directly fixed to the small-diameter portion. If the fixing member 100 is directly fixed to the inner cylindrical shaft 103, thereby increasing the longitudinal length of the portion where the fixing member 100 and the balloon 101 are fixed, the inner diameter of the inner cylindrical shaft 103 at the portion where the fixing member 100 is fixed may be set to the large-diameter portion 109, so as not to impair the tracking ability of the guidewire when passing through a curved portion such as the aortic arch. This prevents the guidewire from getting caught on the distal end of the inner cylindrical shaft even when the balloon catheter is in a curved state when passing through a curved section. Here, the dimensions of the thickened portion 109 of the inner cylindrical shaft are not particularly limited as long as they do not impair the guidewire's ability to follow the curved section, but it is preferable that the inner diameter of the thickened portion 109 of the inner cylindrical shaft be 1.1 to 2 times the inner diameter of the thinned portion of the inner cylindrical shaft 103.

[0052] <Tip Member> As in the balloon catheter according to the fourth embodiment shown in Fig. 7 , the distal end of the inner cylindrical shaft 103 may further include a tapered tip member 108 that narrows toward the tip. The tapered tip member 108 narrows toward the tip, thereby narrowing the clearance between the guidewire and the distal end of the inner cylindrical shaft and preventing the balloon catheter from getting caught on a curved portion such as the aortic arch. Furthermore, if the inner cylindrical shaft 103 has a thickened portion, the inner diameter of the tip member 108 is preferably smaller than the inner diameter of the thickened portion of the inner cylindrical shaft 103. The tip member 108 is preferably made of a flexible material that does not impair the guidewire's tracking ability and can reduce the difference in hardness between the guidewire and the joint. While the material is not particularly limited, a polyether block amide copolymer containing barium sulfate is preferred from the viewpoints of contrast properties and flexibility.

[0053] <Bonding of fixing member, balloon, inner cylindrical shaft, and outer cylindrical shaft> The method for bonding each member is not particularly limited, and examples include bonding with an adhesive, welding, adhesion (heat welding, vibration welding, ultrasonic welding, laser welding, etc.), insert injection molding, outsert injection molding, wrapping with thread, etc. For example, in the case of a material that is difficult to weld, such as natural rubber or synthetic rubber, the members may be bonded by wrapping with thread such as fishing line, and when high pressure is required, the fixing member may be bonded by wrapping with aramid fiber.

[0054] (Example 1) A three-layer tube was molded with an outer layer made of polyether block amide copolymer, an intermediate layer made of a braided structure using stainless steel rectangular wire, and an inner layer made of polyether block amide copolymer, with an outer diameter of 3.1 mm, an inner diameter of 2.6 mm, and a length of 1,050 m.

[0055] Next, a stepped pipe (made of stainless steel, with the thin diameter portion having an outer diameter of 2 mm, an inner diameter of 1.84 mm, and a length of 7 mm, and the thick diameter portion having an outer diameter of 2.4 mm, an inner diameter of 2.24 mm, and a length of 3 mm) was prepared, having a thin diameter portion on the tip side and a thick diameter portion on the base end side. The end of an aramid fiber (length 1200 mm, diameter 0.3 mm) was wrapped around and fixed to the step of the stepped pipe, and the aramid fiber was passed through the braid tube. Then, the thick diameter portion of the stepped pipe and the tip end of the braid tube were fixed with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.), thereby producing outer cylindrical shaft 102.

[0056] A Y-shaped connector having a cap fitting portion into which an O-ring can be fitted was used as the gripping member, and aramid fiber was arranged to be stretched over the entire length of the lumen of the outer cylindrical shaft 102 as the stretch prevention member to act as a stretch prevention member, and with the aramid fiber folded back onto the outer periphery of the base end of the outer cylindrical shaft 102, the base end of the outer cylindrical shaft 102 and the tube connection port of the Y-shaped connector were fixed with an adhesive (cyanoacrylate-based, manufactured by Alteco Co., Ltd.).

[0057] A stainless steel pipe with a handle and a three-stage outer diameter was prepared as a pusher. The different diameter sections of the pusher were, from the base end in the longitudinal direction, a large diameter section, an intermediate section, and a small diameter section. The large diameter section had an outer diameter of 2.1 mm and a length of 60 mm, the intermediate section had an outer diameter of 1.8 mm and a length of 10 mm, and the tapered length from the large diameter section to the intermediate section was 0.5 mm. The small diameter section had an outer diameter of 1.16 mm and a length of 805 mm. The minimum inner diameter of the pusher was 1.0 mm.

[0058] Next, the screw-type cap of the gripping member and an O-ring with an inner diameter of 1.4 mm and a wire diameter of 1.5 mm were fitted onto the pushing member (with the cap facing the base end), and where the O-ring was located at the end of the base end of the intermediate section, a slip-out prevention member was fixed with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.) on the intermediate section of the pushing member, closer to the tip than the O-ring. The slip-out prevention member was made of polyimide and had an inner diameter of 1.9 mm, a thickness of 0.06 mm, and a length of 8.5 mm.

[0059] The tube constituting the inner cylindrical shaft 103 was an inner layer tube (made of polyamide) with a tensile modulus of 1300 MPa (test method: ISO 527) and a yield strength of 40 MPa (test method: ISO 527), with an outer diameter of 1.2 mm, an inner diameter of 1.0 mm, and a length of approximately 305 mm. The base end was expanded in diameter and fixed to the tip of the narrow diameter part of the pushing member with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.). Furthermore, an outer tube (made of polyimide) with a flexural modulus of 3.5 GPa (test method: ASTM D790), a Rockwell hardness of R126 (test method: ASTM D785), an inner diameter of 1.25 mm, an outer diameter of 1.37 mm, and a length of 295 mm was inserted onto the inner tube constituting the inner cylindrical shaft 103 so that the proximal end of the outer tube was in contact with the distal end of the narrow-diameter pipe of the pushing member. Approximately 2 mm of the proximal end of the inner tube was then fixed with adhesive. The distal end of the inner tube was then expanded, and a cylindrical stainless steel pipe (outer diameter 1.16 mm, inner diameter 1.0 mm, length 7 mm) was inserted into the lumen of the tube and fixed with adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.). The distal end of the outer tube was then fixed with adhesive. This formed the inner cylindrical shaft 103. The inner cylindrical shaft assembly, which is composed of the inner cylindrical shaft 103 and the pushing member, is inserted into the outer cylindrical shaft assembly, and the cap of the gripping member is fitted onto the gripping member.

[0060] A balloon was formed by wrapping 3 mm of No. 0.6 nylon thread around the narrow-diameter portion of the stepped pipe of the outer cylindrical shaft 102 and the stainless steel pipe of the inner cylindrical shaft 103 using natural rubber having an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, and securing the wound pieces with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.). This resulted in a round balloon 101 consisting of a single layer of natural rubber. The natural length of the balloon was set to 25 mm.

[0061] The fixing member 100 was made of 48 sets of three round wires made of SUS304 (Young's modulus: 140 MPa, tensile strength: 2300 MPa), which were oriented axially symmetrically and crossed to form a braided structure. The cross-sectional area of ​​the round wires in this fixing member was 0.0019 mm２ This fixing member 100 was placed around the outer periphery of the balloon 101, and the rear end of the fixing member 100 was wound with 425 dtex liquid crystal polyester thread and fixed with an adhesive (cyanoacrylate, manufactured by Toagosei Co., Ltd.) so as to cover the portion where the distal end of the outer cylindrical shaft 102 and the balloon 101 were wound with nylon thread. This procedure was repeated three times. In addition, the distal end of the fixing member 100 was wound with 425 dtex liquid crystal polyester thread and fixed with an adhesive (cyanoacrylate, manufactured by Toagosei Co., Ltd.) so as to cover the portion where the distal end of the inner cylindrical shaft 103 and the balloon 101 were wound with nylon thread. This procedure was repeated three times. As a result, the distal end of the inner cylindrical shaft 103 and the rear end of the fixing member 100 were fixed to each other, and the distal end of the outer cylindrical shaft 102 and the rear end of the fixing member 100 were fixed to each other via the balloon, and the balloon catheter 10 was completed.

[0062] (Example 2) The material of the fixing member 100 is a 0.0038 mm ２ The manufacturing process was the same as in Example 1, except that the material was changed to SUS304.

[0063] Example 3 The balloon 101 was produced in the same manner as in Example 1, except that the balloon 101 was changed to a two-layer balloon, using a natural rubber layer with an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm as the inner layer, and a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist as the surface layer, and the mesh was bonded together with rubber cement (KST-1, manufactured by Sogo Shoten Co., Ltd.).

[0064] (Example 4) The material of the fixing member 100 is a 0.0038 mm ２ The balloon 101 was manufactured in the same manner as in Example 1, except that the material was changed to SUS304, and the balloon 101 was changed to a two-layer balloon using an inner layer of natural rubber with an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, and a surface layer of a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and the mesh was bonded together with rubber cement (KST-1, Sogo Shoten Co., Ltd.).

[0065] (Example 5) The material of the fixing member 100 is a 0.0038 mm ２ The balloon 101 was manufactured in the same manner as in Example 1, except that the material was changed to SUS304, the balloon 101 was changed to a three-layer balloon using an inner layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, an intermediate layer of mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and a surface layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, which were bonded together with rubber cement (KST-1, Sogo Shoten Co., Ltd.).

[0066] (Example 6) The material of the fixing member 100 is a 0.0063 mm ２ The balloon 101 was manufactured in the same manner as in Example 1, except that the material was changed to SUS304, the balloon 101 was changed to a three-layer balloon using an inner layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, an intermediate layer of mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and a surface layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, which were bonded together with rubber cement (KST-1, Sogo Shoten Co., Ltd.).

[0067] (Example 7) The material of the fixing member 100 is a 0.0095 mm ２ The balloon 101 was manufactured in the same manner as in Example 1, except that the material was changed to SUS304, the balloon 101 was changed to a three-layer balloon using an inner layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, an intermediate layer of mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and a surface layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, which were bonded together with rubber cement (KST-1, Sogo Shoten Co., Ltd.).

[0068] (Example 8) The material of the fixing member 100 is a 0.0063 mm ２The balloon 101 was manufactured in the same manner as in Example 1, except that the material was changed to tungsten (Young's modulus: 270 GPa, tensile strength: 2800 MPa), and the balloon 101 was changed to a three-layer balloon using a natural rubber layer having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm as the inner layer, a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist as the middle layer, and a natural rubber layer having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm as the surface layer, which were bonded together with rubber cement (KST-1, manufactured by Sogo Shoten Co., Ltd.).

[0069] Example 9 The stainless steel pipe attached to the distal end of the inner cylindrical shaft 103 was changed to a single-step stainless steel pipe (thinner diameter portion: outer diameter 1.16 mm, inner diameter 1.00 mm, length 5 mm; thicker diameter portion: outer diameter 1.7 mm, inner diameter 1.5 mm, length 6 mm). The same manufacturing method as in Example 1 was used, except that the distal end of the fixing member 100 was fixed directly to the thicker diameter portion at the tip of the inner cylindrical shaft 103, and the distal end of the balloon 101 was fixed directly to the distal side of the thin portion of the inner cylindrical shaft 103.

[0070] Furthermore, the tip member 108 was fitted and fixed to the distal end of the inner cylindrical shaft 103, to which the fixing member 100 was attached, using an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.), to form Example 9. The tip member 108 had a large diameter section and a small diameter section from the base end side in the longitudinal direction. The large diameter section had an outer diameter of 4.1 mm, an inner diameter of 3.9 mm, and a length of 5 mm, and was tapered from the large diameter section to the small diameter section. The small diameter section, with a taper length of 8 mm, had a minimum outer diameter of 1.34 mm, an inner diameter of 0.94 mm, and was made of polyether block amide copolymer.

[0071] (Example 10) The material of the fixing member 100 is a 0.0095 mm ２In addition, the balloon 101 was manufactured in the same manner as in Example 1, except that the balloon 101 was changed to a three-layer balloon using an inner layer of polyurethane having a maximum outer diameter of 14 mm and a one-side film thickness of 0.04 mm, an intermediate layer of mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and a surface layer of polyurethane having a maximum outer diameter of 16 mm and a one-side film thickness of 0.04 mm, each layer wrapped with 0.6 No. nylon fishing line to a length of 3 mm and fixed with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.).

[0072] (Example 11) The material of the fixing member 100 is a 0.0123 mm ２ The balloon 101 was manufactured in the same manner as in Example 1, except that the balloon 101 was changed to a three-layer balloon using an inner layer of polyurethane having a maximum outer diameter of 14 mm and a thickness of 0.04 mm on one side, an intermediate layer of mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and a surface layer of polyurethane having a maximum outer diameter of 16 mm and a thickness of 0.04 mm on one side, each layer wrapped with 0.6 No. nylon fishing line to a length of 3 mm and fixed with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.).

[0073] (Example 12) The material of the fixing member 100 is a 0.0095 mm ２The material of the balloon 101 was changed to SUS304. In addition, the balloon 101 was changed to a three-layer balloon, with an inner layer being a natural rubber layer with an inner diameter of 4.5 mm and a one-side film thickness of 0.3 mm, an intermediate layer being a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a Z twist and a false twist number of 424 t / m, and a surface layer being a natural rubber layer with an inner diameter of 4.5 mm and a one-side film thickness of 0.3 mm, all of which were bonded together with rubber cement (KST-1, Sogo Shoten Co., Ltd.). The balloon was manufactured in the same manner as in Example 1, except that the rear end of the fixing member 100 was made of two-ply 1100 dtex para-aramid fiber, and the tip of the fixing member 100 was wound with two-ply 1100 dtex para-aramid fiber yarn and fixed with an adhesive only once.

[0074] Comparative Example 1 The manufacturing was carried out in the same manner as in Example 1, except that the fixing member 100 was not used.

[0075] Comparative Example 2 The manufacturing process was the same as in Example 1, except that the fixing member 100 was not used, and the balloon 101 was changed to a two-layer balloon, in which the inner layer was a layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, and the outer layer was a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and the mesh was bonded together with rubber cement (KST-1, manufactured by Sogo Shoten Co., Ltd.).

[0076] Comparative Example 3 The balloon 101 was produced in the same manner as in Example 1, except that the fixing member 100 was not used, and the balloon 101 was changed to a three-layer balloon, using as the inner layer a layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, as the inner layer, a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, as the middle layer, and a layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm as the surface layer, which were bonded together with rubber cement (KST-1, manufactured by Sogo Shoten Co., Ltd.).

[0077] (Comparative Example 4) The material of the fixing member 100 was a 0.0095 mm２ The balloon 101 was manufactured in the same manner as in Example 1, except that the material was changed to SUS304, the balloon 101 was changed to a three-layer structure in which the inner layer was a layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, the middle layer was a mesh woven into a cylindrical shape with 50 needles using a false twist yarn of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted with a false twist number of 424 t / m and Z twist, and the surface layer was a layer of natural rubber having an inner diameter of 4.5 mm and a film thickness on one side of 0.3 mm, all of which were bonded together with rubber cement (KST-1, manufactured by Sogo Shoten Co., Ltd.), and the fixing member 100 and the balloon 101 were bonded together with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.).

[0078] The structural differences between Examples 1 to 9 are summarized in Table 1, and the structural differences between Comparative Examples 1 to 4 are summarized in Table 2.

[0079]

[0080]

[0081] The characteristics of Examples 1 to 8 and Comparative Examples 1 to 4 were measured by conducting the following tests in the order of (1) external fluid permeability and expansion position retention test, and (2) pressure resistance test, and the results are summarized in Tables 3 and 4. The characteristics of Example 9 were measured by conducting the following (3) simulated blood vessel loop followability test, and the results are summarized in Table 5.

[0082] (1) External Fluid Passability and Expansion Position Retention Test: The center of a transparent hose (inner diameter 18 mm, length 1000 mm) was marked with a black permanent marker, and a 0.035-inch, 260-cm-long guidewire (Cook Medical Devices; Medical Device Approval Number: 22400BZX00511000) was then inserted through the hose. A balloon was then inserted into the hose via the guidewire and placed so that the marking on the hose overlapped the center of the balloon. As the external fluid, water colored with a dye (Kyoritsu Foods Co., Ltd.; red food coloring) at 36°C was pumped through the hose at a flow rate of 5 L / min using a fluid pump. Here, the "expansion position" refers to the target position for balloon expansion treatment of a stenosis or other site. In this test, this refers to the position marked on the transparent hose.

[0083] A. Verification method for an example of a balloon catheter with a fixing member: The grip of the balloon catheter was pulled to expand only the fixing member. At this time, whether the external fluid could pass beyond the balloon was confirmed by observing from the outside of the transparent hose and by visually checking the change in the flow rate of the fluid flowing out of the hose. After that, the balloon was expanded while water was still flowing, and it was visually confirmed whether the center position of the balloon was misaligned with the marking on the hose.

[0084] B. Verification method for an example of a balloon catheter without a fixing member When the balloon was inflated, whether the external fluid could pass beyond the balloon was confirmed by observing from the outside of the transparent hose and by visually checking the change in the flow rate of the fluid flowing out of the hose. In addition, it was visually confirmed whether the center position of the balloon was displaced from the marking on the hose before and after inflation.

[0085] The results of the change in the flow rate of the external fluid and the central position of the balloon with or without fixing members A and B were evaluated with ○, △, or × using the following criteria: ○: The external fluid did not stop, and the position of the balloon did not shift before and after balloon expansion. △: The external fluid did not stop, but the position of the balloon shifted before and after balloon expansion. △: The external fluid stopped, but the position of the balloon did not shift before and after balloon expansion. ×: The external fluid stopped, and the position of the balloon shifted before and after balloon expansion.

[0086] (2) Pressure resistance test: A ring-shaped valve measuring 5 mm thick, 10 mm wide, and 19 mm in inner diameter was created using acrylic resin (AR-M2, manufactured by Keyence Corporation) with a 3D printer (AGILISTA-3200, manufactured by Keyence Corporation). An indeflator (Merit Medical, notification number: 13B1X10229MM0005) and a pressure sensor (AP-V80, manufactured by Keyence Corporation) were connected to the catheter.

[0087] A. Method for confirming the maximum inflation pressure in an example of a balloon catheter with a fixing member: A balloon was inserted inside the simulated valve, and the grip of the balloon catheter was pulled to expand the fixing member so that it came into contact with the inner wall of the artificial valve frame. The handle of the indeflator was then turned to inject water into the shaft as an internal fluid, expanding the balloon. The value of the pressure sensor when the balloon broke was recorded as the maximum inflation pressure.

[0088] B. Method for confirming the maximum inflation pressure in an example of a balloon catheter without a fixing member A balloon was inserted inside the simulated valve, and the handle of the indeflator was turned to inject water as an internal fluid into the shaft, thereby inflating the balloon. The value of the pressure sensor when the balloon broke was recorded as the maximum inflation pressure.

[0089] The effect of the presence or absence of the fixing members A and B on the maximum expansion pressure was evaluated with ○ or × using the following criteria: ○: The maximum expansion pressure was higher than when there was no fixing member. ×: The maximum expansion pressure was lower than when there was no fixing member.

[0090] (3) Test for conformity of simulated blood vessel loop Using a transparent pressure-resistant hose (inner diameter 25 mm, length 70 cm), a loop was created around the center of the loop approximately 16 cm from the end of the pressure-resistant hose to prevent the pressure-resistant hose from flattening, and this was used as a simulated blood vessel. The curvature of the loop created was 5 cm in diameter, when the central axis of the cross section of the pressure-resistant hose was taken as the circumference. The end of the pressure-resistant hose on which the loop was created was the tip side of the simulated blood vessel.

[0091] A 0.035-inch, 260-cm-long guidewire (manufactured by Cook; medical device approval number: 22400BZX00511000) was placed so as to penetrate the simulated blood vessel and the inside of the introducer sheath. The balloon catheters of the Examples and Comparative Examples were then advanced from the proximal end along the guidewire into the simulated blood vessel, and an evaluation was performed to see whether they could advance while following the guidewire. The loop portion within the simulated blood vessel was evaluated as either ○ or × based on the following criteria: ○: Insertion was possible without any of the defects indicated by "×" below (= good followability). ×: When inserted into the loop portion within the simulated blood vessel, the balloon catheter was unable to follow the guidewire, resulting in deformation of the guidewire, or the balloon catheter peeled off the coating of the guidewire (= poor followability).

[0092]

[0093]

[0094]

[0095] Regarding the external fluid permeability and expansion position retention tests, as shown in Tables 3 and 4, for Examples 1 to 8 and 10 to 12, the passage of water was confirmed and the balloon was able to be fixed without shifting from the intended position, whereas for Comparative Examples 1 to 4, the passage of water was not confirmed and further, the balloon was shifted from the intended position when expanded.

[0096] Regarding the pressure resistance test, as shown in Tables 3 and 4, Examples 1 and 2, which had a balloon consisting of only a single layer of natural rubber and which had a fixing member, achieved a higher inflation pressure until balloon failure compared to Comparative Example 1, which did not have a fixing member, despite using a balloon of the same structure, achieving a pressure resistance of 3 atm or more. Furthermore, Examples 3 and 4, which had a two-layer balloon consisting of a natural rubber inner layer and a braided resin fiber surface layer and which had a fixing member, achieved a higher inflation pressure until balloon failure compared to Comparative Example 2, which did not have a fixing member, achieving a pressure resistance of 7 atm or more. Furthermore, Examples 5 to 8 and 12, which had a three-layer balloon consisting of a natural rubber surface layer, a braided middle layer, and a natural rubber inner layer and which had a fixing member, and Examples 10 and 11, which had a three-layer balloon consisting of a polyurethane surface layer, a braided middle layer, and a polyurethane inner layer and which had a fixing member, achieved a higher inflation pressure until balloon failure compared to Comparative Example 3, which did not have a fixing member, achieving a pressure resistance of 20 atm or more. From the above, it was observed that pressure resistance was improved by placing the fixing member on the outer periphery of the balloon and expanding the diameter of the fixing member before expanding the balloon.

[0097] Furthermore, for Comparative Example 4, the pressure resistance was improved compared to Comparative Example 3, which did not have a fixing member, but because the fixing member and the balloon were joined at a surface, it was confirmed that the blood flow was blocked and the expansion position was misaligned. From this, it was confirmed that although the pressure resistance was improved by having the fixing member on the outside of the balloon, external fluids could not pass through, and the expansion position could not be maintained.

[0098] When checking the maximum expansion pressure values ​​in the pressure resistance test in Tables 3 and 4, as mentioned above, an expansion pressure of 2 to 3 atm is required to treat aortic valve stenosis. ２ This is considered to be achieved if the balloon is made of one or more layers of elastic material. In addition, as mentioned above, an expansion pressure of 7 atm or more is required to place a stent. Therefore, the cross-sectional area of ​​the wire of the fixing member is 0.0038 mm ２This is considered to be achieved if the balloon is made up of two or more layers, consisting of an elastic material and a braided layer. ２ As described above, it was confirmed that this can be achieved if the balloon is configured with three or more layers of elastic material and braided layer.

[0099] The simulated blood vessel loop tracking test simulated whether the balloon catheter could follow the guidewire at a curved portion of the blood vessel during delivery to the affected area. As shown in Table 5, Example 9 showed good tracking ability.

[0100] The present invention makes it possible to perform a wide range of surgical procedures, from procedures requiring high pressure resistance, such as artificial valve crushing, which was previously difficult, to aortic valve dilation, which only requires low pressure resistance.

[0101] 10...balloon catheter, 100...fixing member, 101...balloon, 102...outer cylindrical shaft, 103...inner cylindrical shaft, 104...distal end of outer cylindrical shaft, 105...distal end of inner cylindrical shaft, 106...braided layer, 107...elastic material, 108...tip member, 109...thick diameter portion of inner cylindrical shaft

Claims

1. A flexible outer cylindrical shaft, A flexible inner cylindrical shaft inserted into the outer cylindrical shaft, A balloon fixed to the outer cylindrical shaft and expanding or contracting in the short direction by the pressure of internal fluid supplied through the space inside the outer cylindrical shaft, A fixing member disposed on the outer peripheral side of the balloon and expanding or contracting in diameter in the short direction independently of the balloon by the relative movement in the longitudinal direction between the outer cylindrical shaft and the inner cylindrical shaft, The tip of the inner cylindrical shaft and the tip of the fixing member are fixed to each other, and the tip of the outer cylindrical shaft and the rear end of the fixing member are fixed to each other, The fixing member has a gap through which external fluid can pass when the diameter is expanded, a balloon catheter.

2. The fixing member is made of a wire, The wire has any one of the shapes of a braided shape, a woven shape, a spiral shape, and a straight shape, the balloon catheter according to Claim 1.

3. The wire has a Young's modulus of 60 to 500 GPa and a tensile strength of 500 MPa or more, the balloon catheter according to Claim 1 or 2.

4. The inner cylindrical shaft includes a large-diameter portion provided at the distal end of the inner cylindrical shaft and a small-diameter portion provided at the proximal end of the inner cylindrical shaft and having an inner diameter smaller than that of the large-diameter portion, The balloon is fixed to the small-diameter portion of the inner cylindrical shaft, The fixing member is directly fixed to the large-diameter portion of the inner cylindrical shaft, the balloon catheter according to Claim 1 or 2.

5. The cross-sectional area of the wire is 0.0019 mm ２ or more, The balloon is composed of one or more layers including a layer of an elastic material, For treating aortic valve stenosis, the balloon catheter according to Claim 1 or 2.

6. The cross-sectional area of the wire is 0.0038 mm ２ or more, The balloon is composed of two or more layers including a layer of an elastic material and a braided layer of resin fibers, For stent expansion, the balloon catheter according to Claim 1 or 2.

7. The cross-sectional area of the wire is 0.0063 mm ２ or more, The balloon is composed of three or more layers including a layer of an elastic material and a braided layer of resin fibers, For artificial valve fragmentation, the balloon catheter according to Claim 1 or 2.