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

[Technical Field]

[0001] This invention relates to a balloon catheter used in the medical field. [Background technology]

[0002] Medical balloon catheters generally consist of a shaft and a balloon formed at its tip, and treatment is performed minimally invasively by expanding the balloon. Specific therapeutic applications include arrhythmia treatment, embolic material removal, angioplasty, and balloon aortic valve repair.

[0003] In angioplasty and balloon aortic valve repair, the balloon catheter itself can be used to dilate a narrowed body lumen, or to deploy an expandable internal prosthesis such as a stent after it has been delivered into the body lumen by expanding the balloon.

[0004] Furthermore, when a new artificial valve is implanted transcatheterally due to deterioration of a surgically implanted valve, the valve orifice area may become narrower. Therefore, to widen the valve orifice area, a treatment can be performed to break up the frame of the surgically implanted artificial valve by dilation with a balloon catheter.

[0005] In balloon catheter treatment, the required inflation pressure varies depending on the treatment method. For example, treating aortic valve stenosis requires an inflation pressure of 2-3 atm or higher, while the balloon required to expand and place a stent requires an inflation pressure of 7 atm or higher. Furthermore, an inflation pressure of 15 atm or higher is required to break up the frame of a surgically implanted artificial valve.

[0006] In surgical techniques that use balloon catheters to expand lesions or organs such as blood vessels, a balloon catheter has been reported that, in order to achieve both flexibility to follow the curvature of the biological lumen and sufficient strength to expand it, has two layers, an inner layer and an outer layer, in which a tubular mesh reinforcing member is placed between the inner and outer layers, and the reinforcing member is fixed only at the ends of the inner and outer layers, without directly fixing the intermediate portion (Patent Document 1).

[0007] Furthermore, in surgical procedures for delivering and deploying expandable internal prostheses such as artificial valves and stents to a target site within a body lumen, a balloon catheter equipped with an adjustment device for adjusting the balloon position relative to a compression-type artificial valve has been reported, enabling physicians to accurately control the positioning of the artificial valve at the intended implantation site (Patent Document 2).

[0008] Furthermore, a surgical technique has been reported for pulverizing artificial valves using a balloon with improved pressure resistance due to the spiral arrangement of high-strength fibers inside (Non-Patent Literature 1).

[0009] Furthermore, there is a procedure to remove blood clots, thrombi, occlusions, or obstructions that are hindering blood flow in an artery by engaging and removing a stent retriever that has been deployed by self-expansion. After blood clot removal, an intravascular device has been reported in which the self-expanding stent retriever is further expanded with a semi-compliant balloon and then detached from the shaft for placement. (Patent Document 3) [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2016-052447 [Patent Document 2] Japanese Patent Publication No. 2020-062399 [Patent Document 3] Japanese Patent Publication No. 2021-013743 [Non-patent literature]

[0011] [Non-Patent Document 1] 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. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The catheter described in Patent Document 1 includes a tubular mesh-like member (such as a high-strength fiber with a tensile breaking strength of 2 GPa or more and an elastic modulus of 50 GPa or more) that constitutes 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 specific position, the inner layer, intermediate layer, and outer layer of the balloon are integrated, so when the balloon is inflated at the desired position, it is carried away by the blood flow and its position shifts. Furthermore, because the position shifts during inflation, it becomes necessary to inflate the balloon multiple times to reposition it, stopping the blood flow each time.

[0013] Furthermore, with regard to the catheter described in Patent Document 2, when inflating the balloon at the target location, the balloon may slip due to blood flow, causing displacement or deviation from the target location. If such balloon displacement occurs, it becomes necessary to deflate the balloon again and perform the same procedure, which prolongs the surgical time.

[0014] Furthermore, regarding the catheter described in Non-Patent Document 1, there is a problem in that when the balloon is inflated to the target position, it is carried away by the blood flow and shifts position. In addition, because it shifts from the target position during inflation, multiple balloon inflations are required, which can lead to accidental inflation of the artificial valve leaflets or left ventricular outflow tract, causing symptoms such as artificial valve dysfunction or atrioventricular block.

[0015] Furthermore, the endovascular device of Patent Document 3 has a structure in which the stent retriever and the shaft are separable, and therefore has a problem that it is difficult to use in procedures requiring high pressure. Additionally, since the stent retriever is self-expanding, it is necessary to use it in combination with a member such as a microcatheter for delivery into a blood vessel.

[0016] Accordingly, an object of the present invention is to provide a balloon catheter that can independently and reliably fix a balloon at a target position without blocking blood flow.

Means for Solving the Problems

[0017] As a result of intensive studies to solve the above problems, the present inventors have found the following inventions (1) to (7). (1) A balloon catheter comprising: a flexible outer shaft; a flexible inner shaft inserted through the outer shaft; a balloon fixed to the outer shaft, the balloon expanding or contracting in a lateral direction by pressure of an internal fluid supplied through a space inside the outer shaft; and a fixing member disposed on an outer peripheral side of the balloon, the fixing member expanding or contracting in diameter in a lateral direction independently of the balloon by mutual movement of the outer shaft and the inner shaft in the longitudinal direction, wherein a distal end portion of the inner shaft and a distal end portion of the fixing member are fixed to each other, a distal end portion of the outer shaft and a rear end portion of the fixing member are fixed to each other, and the fixing member has a gap that allows external fluid to pass through when the diameter is expanded. (2) The balloon catheter according to (1), wherein the fixing member is made of a wire rod, and the wire rod has any one shape selected from a braided shape, a woven shape, a spiral shape, and a linear shape. (3) The balloon catheter according to (1) or (2), wherein the wire rod 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 comprises 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 having a smaller inner diameter than 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 above wire is 0.0019 mm². 2 The balloon catheter described in any of (1) to (4) above consists of one or more layers including a layer of elastic material and is for the treatment of aortic valve stenosis. (6) The cross-sectional area of ​​the above wire is 0.0038 mm². 2 The balloon catheter described in any of (1) to (4) above comprises two or more layers, including a layer of elastic material and a braided layer of resin fibers, and is for stent expansion. (7) The cross-sectional area of ​​the above wire is 0.0063 mm². 2 The balloon catheter described in any of (1) to (4) above comprises three or more layers, including a layer of elastic material and a braided layer of resin fibers, and is for artificial valve lithotripsy. [Effects of the Invention]

[0018] According to the present invention, a fixing member with a gap is placed on the outside of the balloon so as not to block external fluids such as blood flow, and since the fixing member and the balloon can expand and contract independently, the fixing member alone can be expanded by the movement of the inner cylinder shaft in the longitudinal direction, thereby fixing it in the lumen without blocking external fluids, and then treatment can be performed by expanding the balloon. This reduces the effect of blood flow blockage and minimizes balloon displacement. Furthermore, if the fixing member is rigid, a wide range of surgical procedures can be performed, from those requiring high pressure resistance, such as artificial valve lithotripsy, which was previously difficult, to aortic valve dilation, which only requires low pressure resistance. [Brief explanation of the drawing]

[0019] [Figure 1]This is a cross-sectional view of a balloon catheter according to the first embodiment of the present invention, when the fixing member is expanded in diameter and the balloon is inflated. [Figure 2] This is a cross-sectional view of the fixing member according to the first embodiment of the present invention when its diameter is reduced and the balloon is deflated. [Figure 3] This is a cross-sectional view of the fixing member according to the first embodiment of the present invention when its diameter is expanded and the balloon is contracted. [Figure 4] This figure shows an example of a treatment method using the first embodiment of the present invention. [Figure 5] This is a cross-sectional view of the vicinity of the balloon of a balloon catheter according to a second embodiment of the present invention. [Figure 6] This is a cross-sectional view of the vicinity of the balloon of a balloon catheter according to a third embodiment of the present invention. [Figure 7] This is a cross-sectional view of the vicinity of the balloon of a balloon catheter according to a fourth embodiment of the present invention. [Modes for carrying out the invention]

[0020] The balloon catheter of the present invention comprises a flexible outer cylindrical shaft, a flexible inner cylindrical shaft inserted through the outer cylindrical shaft, a balloon fixed to the outer cylindrical shaft and expanding or contracting in the short direction by the pressure of an internal fluid supplied through the space within the outer cylindrical shaft, and a fixing member positioned on the outer circumference of the balloon and expanding or contracting in the short direction independently of the balloon due to the mutual movement of the outer cylindrical shaft and the inner cylindrical shaft in the longitudinal direction, wherein the tip of the inner cylindrical shaft and the tip of the fixing member are fixed to each other, the tip 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 that allows external fluid to pass through when it expands.

[0021] The present invention will be described in detail below, along with its embodiments.

[0022] In this specification, "distal end" means the longitudinal end of the component shown in the specification when the operator recognizes the balloon catheter, and "proximal end" means the proximal end of the component shown in the specification of the balloon catheter when the operator recognizes the balloon catheter. Furthermore, "fixed" means that the two components are fixed together, and unless otherwise specified, they may be fixed together via other components.

[0023] "Internal fluid" refers to the fluid that flows inside the balloon, such as liquids like water or saline solution, or gases like nitrogen gas. "External fluid" refers to the fluid that flows outside the balloon, such as blood that flows 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 the internal fluid is injected into the balloon. "Inelastic material" refers to a material with low elasticity, meaning its modulus of elasticity (Young's modulus) at room temperature (test method: ISO6892-1) is approximately 10 GPa or higher.

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

[0025] <Fixing components> In the present invention, the fixing member 100 in the balloon catheter 10 is fixed to the tip of the inner cylinder shaft 103 (described later) and to the rear end of the fixing member 100, and is positioned on the outer circumference of the balloon 101. Therefore, due to the mutual movement of the outer cylinder shaft 102 and the inner cylinder shaft 103 in the longitudinal direction, the structure of the balloon catheter 10 changes as shown in Figure 2 (cross-sectional view when the fixing member 100 is reduced in diameter and the balloon 101 is deflated) and Figure 3 (cross-sectional view when the fixing member 100 is expanded in diameter and the balloon 101 is deflated), respectively. This allows the fixing member 100 to expand or contract in the short direction independently of the balloon 101 without using internal fluid. In other words, the balloon catheter 10 itself can be fixed to the body cavity simply by moving the inner cylinder shaft 103 to the desired position within the body cavity. For example, a narrowed area in a body cavity can be treated using the balloon catheter 10 by following the procedure (steps (1) to (4)) of the treatment method using the balloon catheter according to the first embodiment shown in Figure 4. Furthermore, since the fixing member 100 has a gap that allows external fluid to pass through when it expands, the balloon catheter 10 itself can be fixed to the body cavity without blocking the external fluid flowing into the body cavity, even when it is expanding.

[0026] The fixing member 100 should have high rigidity and a gap that does not block external fluid, but it is preferably made of wire. The specific structure of the wire is preferably one of the following: a braided shape formed by weaving together straight resin fibers or metal wires by tying or intertwining them and arranging them in an alternating pattern (crossing them alternately); a woven shape formed by weaving together straight fibers or metal wires; a spiral shape formed by winding one or more fiber materials in a spiral shape; or a linear shape formed by arranging one or more fiber materials parallel to the axial direction of the balloon 101. A combination shape of any of these shapes is also acceptable.

[0027] Furthermore, braided and woven shapes can be obtained, for example, by assembling, braiding, or weaving multiple wires of inelastic material. Here, "assembling" broadly means combining wires to maintain their shape, and "braiding" refers to the process of creating a fabric-like structure by tying or intertwining wires and assembling them in an alternating pattern (crossing them alternately). "Weaving" refers to the process of creating a fabric-like structure (woven fabric structure) by crossing warp threads and weft threads according to certain rules. Furthermore, as for gaps that do not block external fluid, for example, if the external fluid is blood, the size of the gap is 0.002 mm. 2 It is preferable that the above conditions are met.

[0028] Furthermore, while the material of the fixing member 100 is not particularly limited, it is preferable that its Young's modulus (test method: ISO6892-1) is 60 GPa to 500 GPa and its tensile strength is 500 MPa or more, and more preferably that it is 100 GPa to 500 GPa and its tensile strength is 500 MPa or more. In addition, a characteristic of the fixing member 100 is its cross-sectional area of ​​0.0019 mm². 2 Preferably, it is 0.0063 mm or more. 2 The following is preferable. It is also preferable that the material be made of an X-ray opaque material. For example, carbon or metal approved for medical use can be used. If it is a metal, examples include elemental 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 viewpoint of workability and economy, stainless steel is preferable, from the viewpoint of Young's modulus, tungsten or cobalt-chromium alloy (cobalt-chromium-molybdenum, etc.) is preferable, 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 stenosis, the required expansion pressure is 2 to 3 atm or more, so the cross-sectional area is 0.0019 mm 2 or more is preferable. In the case of stent placement, the required expansion pressure is 7 atm or more, so 0.0038 mm 2 or more of cross-sectional area is preferable. In the case of prosthetic valve crushing, the required expansion pressure is 15 atm or more, so 0.0063 mm 2 or more of cross-sectional area is preferable.

[0030] Further, the cross-sectional shape of the fixing member 100 is not particularly limited, but a circular shape is preferable from the viewpoint of workability, and a rectangular shape is preferable from the viewpoint of bendability and friction of the fixing member.

[0031] <Balloon> The balloon 101 has a structure that can be expanded or contracted in the lateral direction by the pressure of internal fluid supplied through a space in the outer cylinder shaft 102 described later. The structure of the balloon 101 is preferably formed of one layer or a multilayer of two or more layers, as shown in the cross-sectional view of the balloon catheter of the first embodiment in Fig. 1 and the cross-sectional view of the balloon catheter of the second embodiment in Fig. 5.

[0032] Furthermore, in the case of a single-layer balloon 101, it is preferable that the inner layer forming the inner surface is made of a layer of elastic material 107; in the case of a two-layer balloon, it is preferable that the inner layer forming the inner surface is made of a layer of elastic material 107; and in the case of a multilayer balloon of three or more layers, it is preferable that the outer 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 any general rubber elastic material is acceptable. As for rubber elastic materials, for example, those with a hardness of 15 to 80 according to JIS-A are preferred. 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® and Viton®), butyl rubber, synthetic polyisoprene rubber, styrene-butadiene rubber, tetrafluoroethylene propylene copolymer, thermoplastic copolyester, polyurethane, etc. Furthermore, different materials may be selected for each section of the balloon wall or for each layer of the balloon, or two or more materials may be mixed to adjust the modulus of elasticity according to the intended use. From the viewpoint of processability and cost-effectiveness, natural rubber (latex) is preferable, while from the viewpoint of pressure resistance and cost-effectiveness, polyurethane is preferable.

[0033] Natural rubber refers to rubber that occurs naturally, and is usually obtained as natural rubber latex, which is an emulsion in which natural rubber particles are dispersed in a medium such as water.

[0034] Within limits that do not impair the effects of the present invention, if the balloon 101 has two layers, a braided layer 106 made of resin fibers may be included as the surface layer of the balloon 101, and if it has three or more layers, a braided layer 106 made of resin fibers may be included as an intermediate layer inside the balloon 101. The material of the resin fibers is not particularly limited, but any material commonly used for resin fibers may be used, 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 copolymer or its saponified product, polystyrene, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide, aromatic polyamide, polyimide, polyamide-imide, cellulose, cellulose acetate, polyvinylidene chloride, polyacrylonitrile, polyvinyl alcohol, etc., and copolymers thereof. In particular, polyester and polyurethane are preferably used from the viewpoint 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 characteristics. Specifically, it may be a perfectly circular cross-section or a non-circular cross-section. Specific examples of non-circular cross-sections include, but are not limited to, multi-lobed, polygonal, flattened, elliptical, C-shaped, H-shaped, S-shaped, T-shaped, W-shaped, X-shaped, Y-shaped, grid-shaped, and hollow shapes. Furthermore, multiple types of cross-sectional shapes may be employed.

[0036] When using resin fibers as a composite false twist yarn, the weight ratio of the core resin fiber to the sheath resin fiber is not particularly limited. For example, when using a composite false twist yarn of urethane fiber and polyester fiber, if the weight of the urethane fiber is in the range of 30 to 70% of the total weight (assuming the total weight is 100%), sufficient stretchability can be obtained, and the polyester fiber, which is the sheath yarn, can sufficiently cover the core yarn, so effects such as improved abrasion resistance can be expected. The degree of entanglement of the composite false twist yarn is not particularly limited, but is preferably 50 to 150. If the degree of entanglement is 50 or higher, the separation of the core yarn and the sheath yarn is suppressed. Also, if it is 150 or lower, it is preferable because there is no decrease in the stretch recovery rate.

[0037] Furthermore, the knitting method for the braided layer 106 can be warp knitting, weft knitting, or plain knitting, as long as it provides 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, but methods such as bonding with adhesive, heat pressing, kneading, extrusion molding, resin impregnation, and coating can be used. For example, a balloon may be obtained by bonding a braided layer 106, formed by knitting a false twist yarn made of polyurethane and polyester into a tubular shape, with natural rubber using rubber adhesive.

[0039] Various additives may be included in the elastic material 107 at a concentration of 30% by mass or less relative to 100% by mass, as long as they do not impair the effects of the present invention. Examples of such additives include X-ray contrast agents, colorants, antioxidants, heat stabilizers, lubricants, etc. There is no particular lower limit to the content of additives, and it is acceptable even if it is 0% by mass relative to 100% by mass of the elastic material. Furthermore, inorganic or organic particles may be included in the elastic material 107 at a concentration of 20% by mass or less relative to 100% by mass, as long as they do not impair the performance of the present invention. Examples include calcium carbonate, titanium dioxide, silicon dioxide, calcium fluoride, lithium fluoride, alumina, barium sulfate, zirconia, calcium phosphate, cross-linked polystyrene particles, and metal nanoparticles. There is no particular lower limit to the content of inorganic or organic particles, and it is acceptable even if it is 0% by mass 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 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 a balloon consisting of one or more layers including a layer of elastic material 107 is preferred. When used for stent placement, the required expansion pressure is 7 atm or more, so a balloon consisting of two or more layers including an inner layer of elastic material 107 and an outer layer of braided material 106 is preferred. When used for artificial valve lithotripsy, the required expansion pressure is 15 atm or more, so a balloon consisting of three or more layers including an outer layer of elastic material 107, an intermediate layer of braided resin fiber 106, and an inner layer of elastic material 107 is preferred.

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

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

[0043] When the outer shaft 102 consists of a single layer of tubing, the material used for the outer shaft 102 is preferably made of a polymer material with excellent antithrombotic properties, as it comes into contact with biological tissue. Examples include vinyl chloride, polyurethane, polyamide, polyether block amide copolymer, polypropylene, polyolefin, or polyethylene terephthalate. It is preferable that the outer shaft 102 be made of polyurethane or polyether block amide copolymer, which matches the material of the balloon 101, in order to enable heat welding with the balloon.

[0044] If the outer shaft 102 is a multilayer tube, the outer layer of the outer shaft 102 is in contact with biological tissue, so it is preferable that it be formed from a polymer material with excellent antithrombotic properties. Examples of such polymer materials include vinyl chloride, polyurethane, polyamide, polyether block amide copolymer, polypropylene, polyolefin, or polyethylene terephthalate. It is preferable that the polymer material be polyurethane or polyether block amide copolymer, which matches the material of the balloon 101, in order to enable heat welding with the balloon 101.

[0045] If the outer cylindrical shaft 102 is a multilayer tube, the intermediate layer of the outer cylindrical shaft 102 preferably includes a metal flat wire or the like, as durability and rigidity are required. As the metal, it is preferable to use, for example, stainless steel, which is commonly used in medical devices.

[0046] When the outer cylindrical shaft 102 is a multilayer tube, the inner layer of the outer cylindrical shaft 102 is required to be slippery, and it is preferable that the tube as a whole be formed from a polymer material that has stretch resistance. As the polymer material, it is preferable to use a fluorine-based polymer such as PTFE or a polyether block amide copolymer containing barium. Furthermore, from the viewpoint of adhesion, it is preferable to use a polyether block amide copolymer containing barium.

[0047] In forming the above-mentioned multilayer tubes, the materials used to satisfy the required properties for the outer layer, inner layer, and the overall structure are not particularly limited. Multilayer tubes can be obtained using methods such as bonding with adhesives, thermocompression bonding, multilayer molding by co-extrusion, kneading and extrusion molding, resin impregnation, and surface coating.

[0048] <Internal shaft> The inner cylinder shaft 103 can be any flexible tube shape, for example, formed from a single-layer tube or a multi-layer tube of two or more layers. From the viewpoint of preventing buckling of the guide wire inside the inner cylinder shaft 103, it is preferable to adjust the bending stiffness according to the application, such as by using a two-layer tube with a hard material and a soft material laminated together.

[0049] In the case where the inner cylinder shaft 103 is a single-layer tube consisting only of a layer of polymer material, the polymer material may be, but is not particularly limited to, polyamide, polyether block amide, polyimide, polyether ether ketone, polyphenylene sulfide, polyether imide, or polyamide imide. 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 shaft 103 (test method: ISO 527) preferably have 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 shaft 103 will be less likely to deform when the balloon 101 is stretched, and if it is 1400 MPa or less, it will be easier for the balloon to pass through curved sections such as the aortic arch. Similarly, if the yield strength is 25 MPa or more, it will also be easier for the balloon to pass through curved sections such as the aortic arch. The wall thickness of the inner shaft 103 is preferably 0.1 mm to 0.23 mm.

[0051] Furthermore, as in the balloon catheter according to the third embodiment shown in Figure 6, the inner cylinder shaft 103 has a large diameter portion 109 provided at the distal end of the inner cylinder shaft 103, a small diameter portion provided at the proximal end of the inner cylinder shaft 103 with a smaller inner diameter 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 is directly fixed to the small diameter portion. If the length in the longitudinal direction of the part where the fixing member 100 and the balloon 101 are fixed becomes longer due to the fixing member 100 being directly fixed onto the inner cylinder shaft 103, the inner diameter of the inner cylinder shaft 103 at the part fixed by the fixing member 100 is made into the large diameter portion 109 so as not to impair the guide wire's ability to follow curves such as the aortic arch when passing through curved sections. This prevents the guidewire from getting caught on the tip of the inner shaft, even if the balloon catheter is curved when passing through a curved section. Here, the dimensions of the large-diameter section 109 of the inner 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 large-diameter section 109 of the inner shaft is 1.1 to 2 times the inner diameter of the small-diameter section of the inner shaft 103.

[0052] <End component> Furthermore, as shown in Figure 7, the balloon catheter may be further provided with a tapered tip member 108 at the distal end of the inner shaft 103, which narrows towards the tip. By having a tapered tip member 108 that narrows towards the tip, the clearance between the guide wire and the distal end of the inner shaft can be narrowed, preventing the balloon catheter from getting caught on curved sections such as the aortic arch. Also, if the inner shaft 103 has a large diameter section, it is preferable that the inner diameter of the tip member 108 is smaller than the inner diameter of the large diameter section of the inner shaft 103. In addition, it is preferable that the tip member 108 is made of a flexible material that does not impair the followability of the guide wire and can mitigate the difference in hardness between the guide wire and the connection point. The material is not particularly limited, but from the viewpoint of contrast-enhancing properties and flexibility, a polyether block amide copolymer containing barium sulfate is preferred.

[0053] <Bonding of fixing members, balloon, inner cylinder shaft, and outer cylinder shaft> The method of bonding each component is not particularly limited, but examples include bonding with adhesive, welding, welding (heat welding, vibration welding, ultrasonic welding, laser welding, etc.), insert injection molding, outsert injection molding, and wrapping with thread. For example, in the case of difficult-to-weld materials such as natural rubber or synthetic rubber, the components may be bonded by wrapping them with thread such as fishing line, and if high pressure is required, the fixing components may be bonded by wrapping them with aramid fibers. [Examples]

[0054] (Example 1) The outer layer material is polyether block amide copolymer, and the intermediate layer material is stainless steel flat wire. A braided structure was created using a polyether block amide copolymer as the inner layer material, and a three-layer tube with an outer diameter of 3.1 mm, an inner diameter of 2.6 mm, and a length of 1050 m was molded.

[0055] Next, a stepped pipe with a narrow diameter section at the tip and a wide diameter section at the base (the narrow diameter section has an outer diameter of 2 mm, an inner diameter of 1.84 mm, and a length of 7 mm, while the wide diameter section has an outer diameter of 2.4 mm, and an inner diameter A 2.24mm diameter, 3mm long (made of stainless steel) aramid fiber (1200mm long, 0.3mm in diameter) was prepared, and its end was wrapped around the step of the stepped pipe and secured. After the aramid fiber was passed through the blade tube, the wide-diameter section of the stepped pipe and the tip of the blade tube were fixed together with an adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.) to create the outer cylinder shaft 102.

[0056] A Y-type connector with a cap fitting portion into which an O-ring can be fitted is used as the gripping member, and aramid fibers are arranged to be stretched along the entire length of the lumen of the outer cylinder shaft 102 to act as an anti-stretching member, with the aramid fibers folded back onto the outer circumference of the base end of the outer cylinder shaft 102, and the base end of the outer cylinder shaft 102 and the tube connection port of the Y-type connector are fixed with adhesive (manufactured by Alteco Co., Ltd., cyanoacrylate type).

[0057] As a pressing member, a stainless steel pipe with a handle and a three-stage change in outer diameter was prepared. In the pressing member, when the sections with different diameters were considered as the large diameter section, the middle section, and the small diameter section from the base end in the longitudinal direction, the large diameter section had an outer diameter of 2.1 mm and a length of 60 mm, the middle section had an outer diameter of 1.8 mm and a length of 10 mm, the taper length from the large diameter section to the middle section was 0.5 mm, and the small diameter section had an outer diameter of 1.16 mm and a length of 805 mm. The minimum inner diameter of the pressing member 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 externally fitted onto the pressing member (with the cap at the base end). At the point where the O-ring was located at the base end of the middle section, the anti-slip member was fixed to the middle section of the pressing member, but further forward than the O-ring, using adhesive (cyanoacrylate-based, manufactured by Toagosei Co., Ltd.). The anti-slip member was made of polyimide, with an inner diameter of 1.9 mm, a wall thickness of 0.06 mm, and a length of 8.5 mm.

[0059] As the tube constituting the inner cylinder shaft 103, an inner layer tube (made of polyamide) with a tensile modulus of elasticity of 1300 MPa (test method: ISO 527) and a yield strength of 40 MPa (test method: ISO 527) was used. It had 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 widened and fixed to the tip of the narrow diameter section of the push-in member with an adhesive (manufactured by Toagosei Co., Ltd., cyanoacrylate-based). Furthermore, an outer layer 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 externally fitted onto the inner layer tube constituting the inner cylinder shaft 103 so that the base end of the outer layer tube and the tip of the narrow diameter section of the pipe of the push-in member were in contact, and approximately 2 mm of the base end of the inner layer tube was fixed with adhesive. Furthermore, the tip of this inner layer tube was enlarged, and a cylindrical stainless steel pipe (outer diameter 1.16 mm, inner diameter 1.0 mm, length 7 mm) was fitted into the lumen of the tube and fixed with adhesive (manufactured by Toagosei Co., Ltd., cyanoacrylate type). Finally, the distal end of the outer layer tube and the distal end of the inner layer tube were fixed with adhesive. This constituted the inner cylinder shaft 103. The inner shaft assembly, which consists of the inner shaft 103 and the push-in member, was inserted into the outer shaft assembly, and the cap of the gripping member was fitted onto the gripping member.

[0060] A balloon was formed by wrapping 3mm lengths of 0.6-gauge nylon fishing line around the narrow-diameter section of the stepped pipe of the outer cylinder shaft 102 and around the stainless steel pipe of the inner cylinder shaft 103 using natural rubber with an inner diameter of 4.5mm and a thickness of 0.3mm on one side. This was then fixed with adhesive (Toagosei Co., Ltd., cyanoacrylate-based) to form a balloon. This resulted in a round balloon 101 made of a single layer of natural rubber. The natural length of the balloon was set to 25mm.

[0061] The fixing member 100 was constructed by preparing 48 sets of three round wires made of SUS304 (Young's modulus: 140 MPa, tensile strength: 2300 MPa), oriented symmetrically to one another, and intersecting them to form a braided structure. The cross-sectional area of ​​the round wires in this fixing member was 0.0019 mm². 2 The fixing member 100 was placed on the outer circumference of the balloon 101, and the rear end of the fixing member 100 was wrapped with 425dtex liquid crystal polyester thread and fixed with adhesive (Toagosei Co., Ltd., cyanoacrylate type) to cover the tip of the outer cylindrical shaft 102 and the part where the balloon 101 is wrapped with nylon fishing line. This process was repeated three times. The tip of the fixing member 100 was also wrapped with 425dtex liquid crystal polyester thread and fixed with adhesive (Toagosei Co., Ltd., cyanoacrylate type) to cover the tip of the inner cylindrical shaft 103 and the part where the balloon 101 is wrapped and fixed with nylon fishing line. This process was repeated three times, thereby fixing the tip of the inner cylindrical shaft 103 and the rear end of the fixing member 100 to each other, and fixing the tip of the outer cylindrical shaft 102 and the rear end of the fixing member 100 to each other via the balloon, thus completing the balloon catheter 10.

[0062] (Example 2) The material of the fixing member 100 has a cross-sectional area of ​​0.0038 mm². 2 Except for changing the material to SUS304, it was manufactured in the same manner as in Example 1.

[0063] (Example 3) Balloon 101 was manufactured in the same manner as in Example 1, except that it was modified to a two-layer balloon consisting of a natural rubber layer with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side as the inner layer, and a mesh knitted into a tube with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at a false-twist count of 424 t / m and Z-twist, bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1) as the outer layer.

[0064] (Example 4) The material of the fixing member 100 has a cross-sectional area of ​​0.0038 mm². 2The balloon was manufactured in the same manner as in Example 1, except that the material was changed to SUS304, and balloon 101 was modified to consist of two layers: an inner layer of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, and an outer layer of a mesh knitted into a tube with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at a false-twist count of 424 t / m and Z-twist, bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1).

[0065] (Example 5) The material of the fixing member 100 has a cross-sectional area of ​​0.0038 mm². 2 The balloon was manufactured in the same manner as in Example 1, except that the stainless steel was changed to SUS304, and balloon 101 was modified to consist of three layers, each bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1). The modifications were made as follows: the inner layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side; the middle layer was made of a mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at 424 t / m with a Z twist; and the outer layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side.

[0066] (Example 6) The material of the fixing member 100 has a cross-sectional area of ​​0.0063 mm². 2 The balloon was manufactured in the same manner as in Example 1, except that the stainless steel was changed to SUS304, and balloon 101 was modified to consist of three layers, each bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1). The modifications were made as follows: the inner layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side; the middle layer was made of a mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at 424 t / m with a Z twist; and the outer layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side.

[0067] (Example 7) The material of the fixing member 100 has a cross-sectional area of ​​0.0095 mm². 2The balloon was manufactured in the same manner as in Example 1, except that the stainless steel was changed to SUS304, and balloon 101 was modified to consist of three layers, each bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1). The modifications were made as follows: the inner layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side; the middle layer was made of a mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at 424 t / m with a Z twist; and the outer layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side.

[0068] (Example 8) The material of the fixing member 100 has a cross-sectional area of ​​0.0063 mm². 2 The balloon 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 balloon 101 was modified to consist of three layers: an inner layer of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, an intermediate layer of mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at 424 t / m with a Z twist, and an outer layer of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, all bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1).

[0069] (Example 9) The stainless steel pipe attached to the distal end of the inner cylinder shaft 103 was changed to a stepped stainless steel pipe (the narrow section has an outer diameter of 1.16 mm, an inner diameter of 1.00 mm, and a length of 5 mm; the wide section has an outer diameter of 1.7 mm, an inner diameter of 1.5 mm, and a length of 6 mm). In addition, the fixing of the tip of the fixing member 100 was changed to be directly fixed to the wide section at the tip of the inner cylinder shaft 103, and the fixing of the tip of the balloon 101 was changed to be directly fixed to the tip side of the narrow section of the inner cylinder shaft 103. Otherwise, it was manufactured in the same manner as in Example 1.

[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 adhesive (Toagosei Co., Ltd., cyanoacrylate-based), resulting in Example 9. In the tip member 108, when the base end side in the longitudinal direction was divided into a large diameter section and a small diameter section, 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 had a tapered shape transitioning from the large diameter section to the small diameter section. The small diameter section, with a tapered length of 8 mm, had a minimum outer diameter of 1.34 mm and 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 has a cross-sectional area of ​​0.0095 mm². 2 The material was changed to SUS304. In addition, balloon 101 was manufactured in the same manner as in Example 1, except that it was changed to a balloon consisting of three layers: an inner layer of polyurethane with a maximum outer diameter of 14 mm and a thickness of 0.04 mm on one side; an intermediate layer of mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fibers (33 dtex) and polyester fibers (78 dtex) twisted at a false-twist count of 424 t / m and Z-twisted; and an outer layer of polyurethane with a maximum outer diameter of 16 mm and a thickness of 0.04 mm on one side. Each layer was wrapped with 0.6 nylon fishing line to a length of 3 mm and fixed with adhesive (Toagosei Co., Ltd., cyanoacrylate type).

[0072] (Example 11) The material of the fixing member 100 has a cross-sectional area of ​​0.0123 mm². 2The material was changed to nickel-titanium (Young's modulus: 64 GPa, tensile strength: 2100 MPa). In addition, balloon 101 was manufactured in the same manner as in Example 1, except that it was changed to a balloon consisting of three layers: an inner layer of polyurethane with a maximum outer diameter of 14 mm and a thickness of 0.04 mm on one side; an intermediate layer of mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fibers (33 dtex) and polyester fibers (78 dtex) twisted in a Z-twist with a false-twist count of 424 t / m; and an outer layer of polyurethane with a maximum outer diameter of 16 mm and a thickness of 0.04 mm on one side. Each layer was wrapped with 0.6 nylon fishing line to a length of 3 mm and fixed with adhesive (Toagosei Co., Ltd., cyanoacrylate-based).

[0073] (Example 12) The material of the fixing member 100 has a cross-sectional area of ​​0.0095 mm². 2 The material was changed to SUS304. In addition, the balloon 101 was changed to a three-layer balloon, with the inner layer being a natural rubber layer with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, the middle layer being a mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at a false-twist count of 424 t / m and Z-twist, and the outer layer being a natural rubber layer with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, each layer being bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1). Furthermore, the rear end of the fixing member 100 was made of para-aramid fiber made by twisting two strands of 1100 dtex, and the tip of the fixing member 100 was made by wrapping a para-aramid fiber yarn made by twisting two strands of 1100 dtex around it and fixing it with adhesive in a single step.

[0074] (Comparative Example 1) The device was manufactured in the same manner as in Example 1, except that the fixing member 100 was not used.

[0075] (Comparative Example 2) The balloon was manufactured 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 two-layer balloon consisting of a natural rubber layer with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side as the inner layer, and a mesh knitted into a tube with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at a false-twist count of 424 t / m and Z-twist as the outer layer, and bonded with rubber adhesive (Sogo Shoten Co., Ltd., KST-1).

[0076] (Comparative Example 3) The balloon was manufactured 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 balloon consisting of three layers, each bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1), with the following modifications: the inner layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side; the middle layer was made of a mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at a false-twist count of 424 t / m and Z-twist; and the outer layer was made of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side.

[0077] (Comparative Example 4) The material of the fixing member 100 has a cross-sectional area of ​​0.0095 mm². 2 The balloon 101 was modified to have a three-layer structure, with the material changed to SUS304, and the balloon 101 being formed by bonding the following with rubber adhesive (Sogo Shoten Co., Ltd., KST-1): the inner layer being a layer of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, the middle layer being a mesh knitted in a tubular shape with 50 needles using false-twist yarn made of polyurethane fiber (33 dtex) and polyester fiber (78 dtex) twisted at 424 t / m with Z twist, and the outer layer being a layer of natural rubber with an inner diameter of 4.5 mm and a thickness of 0.3 mm on one side, and the two layers being bonded together with rubber adhesive (Sogo Shoten Co., Ltd., KST-1), and the fixing member 100 and balloon 101 being bonded together with adhesive (Toagosei Co., Ltd., cyanoacrylate type).

[0078] Table 1 summarizes the structural differences between Examples 1-9, and Table 2 summarizes the structural differences between Comparative Examples 1-4.

[0079] [Table 1]

[0080] [Table 2]

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

[0082] (1) External fluid permeability and expansion position retention test A transparent hose (18mm inner diameter, 1000mm length) was marked in the center with a black oil-based marker, and then a 0.035-inch, 260cm long guidewire (Cook Corporation; medical device approval number: 22400BZX00511000) was inserted through the inside of the hose. Subsequently, a balloon was inserted into the hose via the guidewire and positioned so that it overlapped with the marking on the hose and the center of the balloon. As an external fluid, water colored with a dye (Kyoritsu Foods Co., Ltd.; red food coloring) at a temperature of 36°C was flowed into the hose at a flow rate of 5 L / min using a liquid delivery pump. Here, "expansion position" refers to the target position for treatment by balloon expansion of a stenotic area, etc., but in this test, it refers to the position marked on the transparent hose.

[0083] A. Confirmation method in the case of a balloon catheter with a fixing member The fixing member was expanded only by pulling the gripping portion of the balloon catheter. At that time, whether the external fluid could pass over the balloon was visually confirmed by observing from the outside of the transparent hose and by observing the change in the flow rate of the fluid flowing out of the hose. After that, the balloon was expanded while the water was still flowing, and it was visually confirmed whether the center position of the balloon deviated from the marking on the hose.

[0084] B. Confirmation method for balloon catheters without fixing members When the balloon was inflated, we visually confirmed whether the external fluid could pass over the balloon by observing it from the outside of the transparent hose and by observing the change in the flow rate of the fluid flowing out of the hose. We also visually confirmed whether the center position of the balloon deviated from the marking on the hose before and after inflation.

[0085] The changes in the flow rate of the external fluid and the center position of the balloon, depending on the presence or absence of fixing members A and B, were evaluated using the following criteria as ○, △, and ×. ○: The external fluid flow did not stop, and the balloon's position did not shift before and after balloon expansion. △: The external fluid did not stop, but the balloon's position shifted before and after balloon expansion. △: The external fluid flow stopped, but the balloon's position did not shift before and after balloon expansion. ×: The external fluid flow stopped, and the balloon's position shifted before and after balloon expansion.

[0086] (2) Pressure test An annular shape with a thickness of 5 mm, a width of 10 mm, and an inner diameter of 19 mm was fabricated using acrylic resin (AR-M2, manufactured by Keyence Corporation) with a 3D printer (AGILISTA-3200, manufactured by Keyence Corporation) and used as a simulated valve. An indeflerator (Mercedes Medical Co., Ltd., registration number: 13B1X10229MM0005) and a pressure sensor (AP-V80, manufactured by Keyence Corporation) were connected to the catheter.

[0087] A. Method for confirming the maximum expansion pressure in an example of a balloon catheter with a fixing member. A balloon was inserted inside the simulated valve, and the gripping portion of the balloon catheter was pulled to expand the diameter of the fixing member so that it contacted the inner wall of the artificial valve frame. Then, the indeflerator handle was turned to inject water as the internal fluid into the shaft and expand the balloon. The pressure sensor value at the time the balloon burst was recorded as the maximum expansion 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 a simulated valve, and the indefleror handle was turned to inject water into the shaft as the internal fluid, thereby expanding the balloon. The pressure sensor reading at the time the balloon burst was recorded as the maximum expansion pressure.

[0089] The effect of the presence or absence of fixing members A and B on the maximum expansion pressure was evaluated using the following criteria, with a circle (○) or cross (×). ○: The maximum expansion pressure is higher compared to when there is no fixing member. ×: The maximum expansion pressure is lower compared to when there is no fixing member.

[0090] (3) Simulated blood vessel loop followability test Using a transparent pressure-resistant hose (25mm inner diameter, 70cm length), a loop was created around the hose, with the loop's center approximately 16cm from the end of the hose, ensuring the hose did not flatten. This loop served as a simulated blood vessel. The curvature of the created loop, when the central axis of the hose's cross-section was considered the circumference, resulted in a diameter of 5cm. The end of the hose on which the loop was created became the tip of the simulated blood vessel.

[0091] A 0.035-inch, 260 cm long guidewire (Cook Corporation; medical device approval number: 22400BZX00511000) was placed so as to penetrate the inside of the simulated blood vessel and introducer sheath. Subsequently, the balloon catheters of the example and comparative example were introduced into the simulated blood vessel from the proximal end along the guidewire, and their ability to follow the guidewire was evaluated. The loop portion within the simulated blood vessel was evaluated with ○ or × according to the following criteria. ○: Insertion was successful without any of the problems indicated by "×" below (= good responsiveness). ×: When inserting the balloon catheter into the loop portion of the simulated blood vessel, the balloon catheter failed to follow the guidewire, causing deformation of the guidewire's shape, or the balloon catheter peeled off the guidewire's coating (= poor followability).

[0092] [Table 3]

[0093] [Table 4]

[0094] [Table 5]

[0095] Regarding the external fluid permeability and expansion position retention tests, as shown in Tables 3 and 4, water passage was confirmed for Examples 1-8 and 10-12, and the balloons were able to be fixed without shifting from the target position. In contrast, water passage was not confirmed for Comparative Examples 1-4, and furthermore, shifting from the target position was observed when the balloons were expanded.

[0096] Regarding the pressure resistance test, as shown in Tables 3 and 4, Examples 1 and 2, which had balloons consisting of only one layer of natural rubber and equipped with a fixing member, achieved a higher expansion pressure to balloon rupture compared to Comparative Example 1, which did not have a fixing member, despite using balloons of the same structure, and achieved a pressure resistance of 3 atm or higher. Furthermore, Examples 3 and 4, which had balloons consisting of two layers, with natural rubber as the inner layer and a braided resin fiber layer as the outer layer, and equipped with a fixing member, achieved a higher expansion pressure to balloon rupture compared to Comparative Example 2, which did not have a fixing member, and achieved a pressure resistance of 7 atm or higher. In addition, Examples 5 to 8 and 12, which had balloons consisting of three layers, with natural rubber as the outer layer, a braided layer as the middle layer, and natural rubber as the inner layer, and equipped with a fixing member, and Examples 10 to 11, which had balloons consisting of three layers, with polyurethane as the outer layer, a braided layer as the middle layer, and polyurethane as the inner layer, and equipped with a fixing member, achieved a higher expansion pressure to balloon rupture compared to Comparative Example 3, which did not have a fixing member, and achieved a pressure resistance of 20 atm or higher. Based on the above, it was observed that pressure resistance is improved by placing the fixing member on the outer circumference of the balloon and then expanding the diameter of the fixing member in advance before the balloon expands.

[0097] Furthermore, regarding Comparative Example 4, although the pressure resistance was improved compared to Comparative Example 3, which lacked a fixing member, it was confirmed that blood flow was blocked and the expansion position shifted because the fixing member and the balloon were joined over a surface. From this, it was confirmed that although the pressure resistance is improved by having the fixing member on the outside of the balloon, external fluid cannot pass through, and the expansion position cannot be maintained.

[0098] Checking the maximum expansion pressure values ​​for the pressure resistance tests in Tables 3 and 4, we see that, as mentioned above, an expansion pressure of 2-3 atm is required to treat aortic valve stenosis, and therefore the cross-sectional area of ​​the fixing member wire is 0.0019 mm². 2 The above is considered achievable if the balloon consists of one or more layers of elastic material. Furthermore, as mentioned above, an expansion pressure of 7 atm or more is required to implant the stent, so the cross-sectional area of ​​the fixing member wire is 0.0038 mm². 2 The above is considered to be achievable if the balloon is constructed of two or more layers: an elastic material and a braided layer. Furthermore, as mentioned above, an expansion pressure of 15 atm or more is required to crush the artificial valve, so the cross-sectional area of ​​the fixing member wire is 0.0063 mm². 2 In conclusion, it was confirmed that this can be achieved if the balloon is constructed with three or more layers of elastic material and braided layers.

[0099] The simulated vascular loop followability test simulates whether a balloon catheter can follow a guidewire located in a curved section of a blood vessel during delivery to the affected area. As shown in Table 5, Example 9 showed good followability. [Industrial applicability]

[0100] This invention enables a wide range of surgical procedures, from those requiring high pressure resistance, such as artificial valve rupture, which were previously difficult, to aortic valve dilation, which only requires low pressure resistance. [Explanation of Symbols]

[0101] 10...Balloon catheter, 100...Fixation member, 101...Balloon, 102...Outer shaft, 103...Inner shaft, 104...Distal end of outer shaft, 105...Distal end of inner shaft, 106...Braided layer, 107...Elastic material, 108...Tip member, 109...Large diameter section of inner shaft

Claims

1. A flexible outer cylindrical shaft, A flexible inner cylinder shaft inserted through the outer cylinder shaft, A balloon fixed to the outer cylindrical shaft, which expands or contracts in the shorter direction by the pressure of the internal fluid supplied through the space within the outer cylindrical shaft, The balloon has a fixing member positioned on its outer circumference, which expands or contracts in the short direction independently of the balloon due to the mutual movement of the outer cylindrical shaft and the inner cylindrical shaft in the longitudinal direction, The tip of the inner cylinder shaft and the tip of the fixing member are fixed to each other, and the tip of the outer cylinder shaft and the rear end of the fixing member are fixed to each other. The fixing member is a balloon catheter having a gap that allows external fluid to pass through when the diameter is expanded.

2. The aforementioned fixing member is made of wire, The balloon catheter according to claim 1, wherein the wire material has either a braided shape or a woven shape.

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

5. The cross-sectional area of ​​the aforementioned wire is 0.0019 mm². ２ That's all. The balloon consists of one or more layers, including a layer of elastic material. A balloon catheter according to claim 2, for the treatment of aortic valve stenosis.

6. The cross-sectional area of ​​the aforementioned wire is 0.0038 mm². ２ That's all. The balloon consists of two or more layers, including a layer of elastic material and a braided layer of resin fibers. A balloon catheter for stent expansion according to claim 2.

7. The cross-sectional area of ​​the aforementioned wire is 0.0063 mm². ２ That's all. The balloon consists of three or more layers, including a layer of elastic material and a braided layer of resin fibers. A balloon catheter according to claim 2, for use in artificial valve lithotripsy.

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