Balloon catheter system

Abstract

To provide a balloon catheter system capable of determining which part of a balloon is being visually recognized under X-ray fluoroscopy using an X-ray imaging apparatus.SOLUTION: A balloon catheter system includes: an outer resin tube 11; an inner resin tube 12; a balloon 31; a balloon catheter 1 having a first marker 41, a second marker 42, and a third marker 43 being an X-ray impermeable marker 40; and an X-ray imaging apparatus 50. In a longitudinal direction x1, the third marker 43 is positioned between the first marker 41 and the second marker 42. The X-ray imaging apparatus 50 has a first field of view including the first marker 41 in an imaging field of the X-ray imaging apparatus 50, and a second field of view including the second marker 42 in the imaging field of the X-ray imaging apparatus 50. The first field of view may further include the third marker 43 in the imaging field and the second field of view does not include the first marker 41 and the third marker 43 in the imaging field.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a balloon catheter system including a balloon catheter and an X-ray imaging device. [Background technology]

[0002] Catheter therapy is widely used as a minimally invasive treatment for lesions in blood vessels and organs without open surgery. Catheters are inserted into internal lumens, such as blood vessels in the limbs or groin, or the digestive tract, such as the bile duct, and delivered to the lesion site to treat stenotic lesions or to perform procedures or examinations such as administering contrast agents or drugs into blood vessels.

[0003] It is known that various diseases occur when stenosis occurs in blood vessels, which are the channels through which blood circulates in the body, causing blood circulation to stagnate. In particular, stenosis in the coronary arteries that supply blood to the heart can lead to serious diseases such as angina pectoris and myocardial infarction. One method for treating such stenotic areas of blood vessels is angioplasty (PTA, PTCA, etc.), which uses a balloon catheter or stent to expand the stenotic area. Angioplasty is a minimally invasive therapy that does not require open chest surgery like bypass surgery. Angioplasty is also used to treat stenosis that occurs in shunts for dialysis.

[0004] In addition, bile ducts may be blocked by gallstones or tumors, or the flow of bile may be impeded within the bile duct, causing bile to stagnate in the bile duct and lead to bacterial infection. Bacterial infection of the bile can lead to cholangitis, and if bile containing bacteria passes through the liver and enters the bloodstream throughout the body, it may cause sepsis. In such cases, a procedure is required to drain the bile from the bile duct, and a catheter is inserted into the bile duct to perform percutaneous transhepatic biliary drainage (PTCD) or endoscopic biliary drainage (ERBD), etc.

[0005] Patent Document 1 describes a balloon catheter capable of transmitting a pushing force transmitted from a proximal side to a distal side. The balloon catheter includes a balloon, a cylindrical outer shaft constituting an expansion lumen for supplying a fluid for expanding the balloon, an opening control section having a control hole communicating with the expansion lumen, a core wire having a pressing section capable of contacting the control hole of the opening control section, an inner shaft having a guidewire lumen therein for inserting a guidewire, a tip guidewire port formed at the distal end of the inner shaft, and a rear guidewire port formed at the proximal end of the inner shaft, and it is disclosed that the rear guidewire port is formed in the opening control section of the outer shaft.

[0006] Patent Document 2 describes a balloon catheter that can be located or identified during use. The balloon catheter includes a shaft, an inflatable balloon attached to the shaft and having an interior, and at least three radiopaque markings spaced apart along a longitudinal axis of the catheter in the interior of the balloon, wherein a first distance separating a first radiopaque marking from an adjacent second radiopaque marking is different from a second distance separating the second radiopaque marking from an adjacent third radiopaque marking.

[0007] Patent Document 3 describes a balloon catheter that is excellent in pushability and can prevent kinking. The balloon catheter includes an outer shaft, a balloon connected to the tip of the outer shaft, a hub connected to the rear end of the outer shaft, a resin tube that forms a guidewire lumen, the rear end of which opens as a guidewire port on the side surface of the outer shaft, an inner tube whose tip is fixed to the tip of the balloon and whose tip is open, and a core wire having a straight portion and a reduced diameter portion, the core wire is fixed to the inner circumferential surface of the outer shaft, and the straight portion of the core wire is press-fitted between the inner circumferential surface of the outer shaft and the outer circumferential surface of the inner tube, and the cross section of the outer shaft at the portion where the straight portion of the core wire is press-fitted is deformed into an elliptical shape. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2015-013207 A [Patent Document 2] Special Publication No. 2015-527123 [Patent Document 3] JP 2016-083279 A Summary of the Invention [Problem to be solved by the invention]

[0009] Conventional catheters such as those described in Patent Documents 1 to 3 have a radiopaque marker at the portion where the balloon is located, so that the position of the balloon in the lumen of the living body can be confirmed under X-ray fluoroscopy using an X-ray imaging device. By being able to confirm the position of the balloon in the lumen of the living body, it is possible to reliably perform treatment such as dilating the stenosis while checking the position of the balloon and the state of the lumen of the living body where the balloon is located, and it is also possible to shorten the procedure time. However, if the size of the balloon in the longitudinal direction of the catheter is larger than the size of the imaging field of the X-ray imaging device, it is difficult to immediately determine which part of the balloon is being confirmed under X-ray fluoroscopy, and there is room for improvement in terms of shortening the procedure time and reducing the effort of the procedure.

[0010] The present invention has been made in consideration of the above circumstances, and its object is to provide a balloon catheter system that can determine which part of the balloon is visible under X-ray fluoroscopy with an X-ray imaging device. [Means for solving the problem]

[0011] A balloon catheter system according to an embodiment of the present invention that can solve the above problems is as follows. [1] An outer resin tube having a longitudinal direction; an inner resin tube disposed in an inner cavity of the outer resin tube; a balloon disposed at a distal portion of the outer resin tube and capable of expanding and contracting; a balloon catheter having a first marker, a second marker, and a third marker, which are X-ray opaque markers arranged inside the balloon and outside the inner resin tube; and an X-ray imaging device capable of irradiating X-rays and capturing an image of the transmitted X-rays, the third marker is located between the first marker and the second marker in the longitudinal direction, the X-ray imaging device has a first field of view in which the first marker is included in an imaging field of view of the X-ray imaging device, and a second field of view in which the second marker is included in an imaging field of view of the X-ray imaging device, The first field of view may further include the third marker in an imaging field of view of the X-ray imaging device, A balloon catheter system in which the second field of view does not include the first marker and the third marker in the imaging field of view of the X-ray imaging device. [2] The balloon catheter system described in [1], wherein the second field of view does not include other X-ray opaque markers in the imaging field of view of the X-ray imaging device. [3] the first marker is located distal to the third marker; The balloon catheter system according to claim 1, wherein the second marker is located proximally relative to the third marker. [4] The balloon has a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, and a distal tapered portion located distal to the straight tube portion, the straight pipe portion has a length in the longitudinal direction divided into three equal parts, the length being a distal region located at the most distal side, a proximal region located at the most proximal side, and a central region located proximal to the distal region and distal to the proximal region, the first marker is disposed in the distal region; the second marker is disposed in the proximal region; The balloon catheter system according to any one of [1] to [3], wherein the third marker is disposed in the central region. [5] the first marker is disposed at a location where a distal end of the straight tube portion is located; The balloon catheter system according to [4], wherein the second marker is positioned at a location where the proximal end of the straight tube portion is located. [6] The balloon catheter system according to any one of [1] to [5], wherein the third marker is located distal to the midpoint of the length of the balloon in the longitudinal direction. [7] The balloon catheter system described in [6], wherein the distance between the midpoint of the length of the balloon in the longitudinal direction and the third marker is smaller than the distance between the first marker and the third marker in the longitudinal direction. [8] A balloon catheter system described in any of [1] to [7], wherein the positions of the first marker, the second marker, and the third marker relative to the balloon are different between an expanded state in which the balloon is expanded and a contracted state in which the balloon is contracted. [9] A balloon catheter system described in any of [1] to [8], wherein the positions of the first marker, the second marker, and the third marker relative to the balloon are the same in an expanded state in which the balloon is expanded and in a contracted state in which the balloon is contracted.

[10] The plurality of radiopaque markers further includes a fourth marker located between the first marker and the second marker in the longitudinal direction; The balloon catheter system according to any one of [1] to [9], wherein the distance between the third marker and the fourth marker in the longitudinal direction is smaller than the distance between the first marker and the third marker in the longitudinal direction.

[11] The balloon catheter system described in

[10] , wherein the distance between the first marker and the third marker in the longitudinal direction is greater than the distance between the first marker and the fourth marker in the longitudinal direction.

[12] A balloon catheter system described in

[10] or

[11] , wherein the distance between the first marker and the fourth marker in the longitudinal direction is smaller than the distance between the second marker and the fourth marker in the longitudinal direction.

[13] The balloon has a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, and a distal tapered portion located distal to the straight tube portion, the straight pipe portion has a length in the longitudinal direction divided into three equal parts, the length being a distal region located at the most distal side, a proximal region located at the most proximal side, and a central region located proximal to the distal region and distal to the proximal region, The balloon catheter system according to any one of

[10] to

[12] , wherein the fourth marker is disposed in the central region. Effect of the Invention

[0012] According to the balloon catheter system, the third marker is located between the first marker and the second marker in the longitudinal direction, the X-ray imaging device has a first field of view in which the first marker is included in the imaging field of view of the X-ray imaging device and a second field of view in which the second marker is included in the imaging field of view of the X-ray imaging device, the first field of view may further include the third marker in the imaging field of view of the X-ray imaging device, and the second field of view does not include the first marker and the third marker in the imaging field of view of the X-ray imaging device, so that it is possible to determine which part of the balloon is being visually recognized by checking the X-ray-opaque marker included in the imaging field of view of the X-ray imaging device. As a result, the position of the balloon and the state of the intravital lumen in which the balloon is located can be confirmed by X-ray fluoroscopy, and it becomes possible to perform minimally invasive treatment using the balloon catheter system. [Brief description of the drawings]

[0013] [Figure 1] 1 illustrates a schematic diagram of a balloon catheter system according to an embodiment of the present invention. [Diagram 2] 2 is a longitudinal cross-sectional view of the balloon catheter shown in FIG. 1. [Diagram 3] 2 illustrates an enlarged view of the distal portion of the balloon catheter shown in FIG. 1. [Figure 4] 2 shows a schematic diagram of a first field of view of the balloon catheter system shown in FIG. 1. [Diagram 5] 2 shows a schematic diagram of a second field of view of the balloon catheter system shown in FIG. 1. [Figure 6]FIG. 2 is a schematic diagram of an X-ray imaging device in the balloon catheter system shown in FIG. 1. [Figure 7] 4 shows a cross-sectional view along the longitudinal direction of a core material according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments, and can be modified as appropriate within the scope of the above and below, and all of these are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, the specification and other drawings should be referred to. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, since priority is given to helping understand the features of the present invention.

[0015] A balloon catheter system according to an embodiment of the present invention is a balloon catheter system including: an outer resin tube having a longitudinal direction; an inner resin tube disposed in the lumen of the outer resin tube; a balloon disposed in the distal portion of the outer resin tube and capable of expanding and contracting; a balloon catheter having a first marker, a second marker, and a third marker which are X-ray opaque markers disposed inside the balloon and outside the inner resin tube; and an X-ray imaging device capable of irradiating X-rays and imaging the transmitted X-rays, wherein the third marker is located between the first marker and the second marker in the longitudinal direction, and the X-ray imaging device has a first field of view in which the first marker is included in the imaging field of the X-ray imaging device and a second field of view in which the second marker is included in the imaging field of the X-ray imaging device, the first field of view may further include the third marker in the imaging field of the X-ray imaging device, and the second field of view does not include the first marker and the third marker in the imaging field of the X-ray imaging device.

[0016] Hereinafter, a balloon catheter system according to an embodiment of the present invention will be described with reference to Figs. 1 to 6. Fig. 1 is a schematic diagram of a balloon catheter system according to an embodiment of the present invention, Fig. 2 is a cross-sectional view along the longitudinal direction of the balloon catheter, Fig. 3 is an enlarged view of a distal portion of the balloon catheter, and Fig. 4 is a schematic diagram of a first field of view in the balloon catheter system, and Fig. 5 is a schematic diagram of a second field of view in the balloon catheter system. Fig. 6 is a schematic diagram of an X-ray imaging device in the balloon catheter system.

[0017] The balloon catheter system includes a balloon catheter 1 and an X-ray imaging device 50 capable of irradiating X-rays and capturing an image of the transmitted X-rays.

[0018] The balloon catheter 1 has an outer resin tube 11 having a longitudinal direction x1, an inner resin tube 12 disposed in the lumen of the outer resin tube 11, a balloon 31 disposed in the distal portion of the outer resin tube 11 and capable of expanding and contracting, and a first marker 41, a second marker 42, and a third marker 43 that are X-ray opaque markers 40 disposed inside the balloon 31 and outside the inner resin tube 12. Hereinafter, the balloon catheter 1 may be simply referred to as the "catheter 1."

[0019] The outer resin tube 11 has a longitudinal direction x1, a radial direction y1 connecting the centroid of the outer edge of the outer resin tube 11 and a point on the outer edge in a cross section perpendicular to the longitudinal direction x1, and a circumferential direction z1 along the outer periphery of the outer resin tube 11 in a cross section perpendicular to the longitudinal direction x1. In this specification, the direction toward the user's hand of the catheter 1 is referred to as the proximal side, and the opposite side to the proximal side, i.e., the direction toward the subject of treatment, is referred to as the distal side. The direction from the proximal side to the distal side of the outer resin tube 11 is referred to as the longitudinal direction x1.

[0020] Members and parts other than the outer resin tube 11 also have longitudinal directions, radial directions, and circumferential directions, which may or may not be the same as the longitudinal direction x1, radial direction y1, and circumferential direction z1 of the outer resin tube 11. However, for ease of understanding, this specification will describe all members and parts as having the same longitudinal directions, radial directions, and circumferential directions as the longitudinal direction x1, radial direction y1, and circumferential direction z1 of the outer resin tube 11.

[0021] The outer resin tube 11 has a longitudinal direction x1 and has an inner cavity extending in the longitudinal direction x1.

[0022] The outer resin tube 11 has a distal end 11d and a proximal end 11p in the longitudinal direction x1. The outer resin tube 11 may have an opening at at least one of the distal end 11d and the proximal end 11p. When the distal end 11d of the outer resin tube 11 has an opening, it is preferable that the opening of the distal end 11d of the outer resin tube 11 communicates with the inner cavity of the outer resin tube 11. When the proximal end 11p of the outer resin tube 11 has an opening, it is preferable that the opening of the proximal end 11p of the outer resin tube 11 communicates with the inner cavity of the outer resin tube 11.

[0023] Examples of materials constituting the outer resin tube 11 include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, polyetherpolyamide resins, polyurethane resins, polyimide resins, fluorine resins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. Among these, the material constituting the outer resin tube 11 is preferably a polyamide resin, and more preferably a polyamide elastomer. When the material constituting the outer resin tube 11 is a polyamide elastomer, the outer surface of the outer resin tube 11 has good slipperiness and the outer resin tube 11 has appropriate rigidity. Therefore, the catheter 1 can be easily inserted into a blood vessel.

[0024] The outer resin tube 11 may have a single-layer structure or a multi-layer structure. When the outer resin tube 11 has a multi-layer structure, for example, the outer resin tube 11 may have a structure in which a middle layer of the resin tube constituting the outer resin tube 11 is made of a metal braid such as stainless steel, carbon steel, or nickel-titanium alloy.

[0025] The inner resin tube 12 is disposed in the lumen of the outer resin tube 11. The inner resin tube 12 has a lumen extending in the longitudinal direction x1. Hereinafter, the outer resin tube 11 and the inner resin tube 12 may be collectively referred to as the "shaft 10."

[0026] The inner resin tube 12 has a distal end 12d and a proximal end 12p in the longitudinal direction x1. The inner resin tube 12 may have an opening at at least one of the distal end 12d and the proximal end 12p. When the distal end 12d of the inner resin tube 12 has an opening, it is preferable that the opening of the distal end 12d of the inner resin tube 12 communicates with the inner cavity of the inner resin tube 12. When the proximal end 12p of the inner resin tube 12 has an opening, it is preferable that the opening of the proximal end 12p of the inner resin tube 12 communicates with the inner cavity of the inner resin tube 12.

[0027] Examples of materials constituting the inner resin tube 12 include the synthetic resins listed above as materials constituting the outer resin tube 11. Among them, the material constituting the inner resin tube 12 is preferably a polyamide resin, and more preferably a polyamide elastomer. By using a polyamide elastomer as the material constituting the inner resin tube 12, the slipperiness of the surface of the inner resin tube 12 can be increased, and appropriate rigidity can be imparted to the inner resin tube 12. As a result, it becomes easier to insert an article such as a guidewire into the inner resin tube 12, and it becomes easier to insert the catheter 1 into a blood vessel.

[0028] The inner resin tube 12 may have a single layer structure or a multi-layer structure. When the inner resin tube 12 has a multi-layer structure, it may have a structure in which a plurality of layers made of synthetic resins or the like listed as materials constituting the outer resin tube 11 are combined. Furthermore, the inner resin tube 12 may have a structure in which a middle layer of the resin tube constituting the inner resin tube 12 is made of a metal braid such as stainless steel, carbon steel, or nickel-titanium alloy.

[0029] The material constituting the inner resin tube 12 may be different from the material constituting the outer resin tube 11, but is preferably the same. By using the same material constituting the inner resin tube 12 and the outer resin tube 11, it becomes easier to increase the bonding strength between the outer resin tube 11 and the inner resin tube 12 when the inner resin tube 12 is placed in the lumen of the outer resin tube 11 and the outer resin tube 11 and the inner resin tube 12 are fixed together.

[0030] Methods for joining the outer resin tube 11 and the inner resin tube 12 include, for example, bonding with an adhesive, welding, attaching a ring-shaped member to the overlapping portion of the outer resin tube 11 and the inner resin tube 12 and crimping, etc. Among these, it is preferable that the outer resin tube 11 and the inner resin tube 12 are joined by welding. By joining the outer resin tube 11 and the inner resin tube 12 by welding, the joining strength between the outer resin tube 11 and the inner resin tube 12 is easily increased, and the joining between the outer resin tube 11 and the inner resin tube 12 can be made difficult to be released.

[0031] 1, a hub 5 may be provided on the proximal side of the shaft 10. In addition, when a fluid is supplied to the inner cavity of the shaft 10, the hub 5 may be provided with a fluid injection section 6 that is in communication with a flow path of the fluid supplied to the inner cavity of the shaft 10.

[0032] The shaft 10 and the hub 5 can be joined by, for example, bonding with an adhesive, welding, or the like. Among these, it is preferable that the shaft 10 and the hub 5 are joined by adhesion. By joining the shaft 10 and the hub 5 by adhesion, it is possible to increase the bonding strength between the shaft 10 and the hub 5 and improve the durability of the catheter 1 when the materials constituting the shaft 10 and the hub 5 are different, for example, when the shaft 10 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0033] 1 and 2 show a so-called rapid exchange type catheter 1 having an opening 13 which is a guidewire port midway from the distal side to the proximal side of the shaft 10, and a guidewire insertion passage from the opening 13 to the distal side of the shaft 10. In the case of the rapid exchange type, the outer resin tube 11 preferably has a distal tube 11a and a proximal tube 11b, and the distal tube 11a and the proximal tube 11b may be separate members. When the distal tube 11a and the proximal tube 11b are separate members, the proximal tube 11b may be made of resin or metal.

[0034] Alternatively, although not shown, the present invention can also be applied to a so-called over-the-wire type catheter 1 having a passage for inserting a guide wire from the distal side to the proximal side of the shaft 10.

[0035] In the case of a rapid exchange type catheter 1, it is preferable that an appropriate coating is applied to the outer wall of at least one of the distal tube 11a and the proximal tube 11b, and it is more preferable that a coating is applied to the outer walls of both the distal tube 11a and the proximal tube 11b. In the case of an over-the-wire type catheter 1, it is preferable that an appropriate coating is applied to the outer wall of the outer resin tube 11.

[0036] The coating can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and can be applied by immersing the shaft 10 in a hydrophilic or hydrophobic coating agent, by applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 10, or by covering the outer wall of the shaft 10 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs or additives.

[0037] Examples of hydrophilic coating agents include hydrophilic coating agents made of hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, or any combination thereof.

[0038] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coat, diamond coat, diamond-like carbon (DLC) coat, ceramic coat, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0039] The balloon 31 is disposed at the distal portion of the outer resin tube 11 and is capable of expanding and contracting.

[0040] The balloon 31 preferably has a straight pipe section 34, a proximal taper section 33 located proximally of the straight pipe section 34, and a distal taper section 35 located distally of the straight pipe section 34 in the longitudinal direction x1. The straight pipe section 34 is preferably formed in a substantially cylindrical shape extending in the longitudinal direction x1, and the length (outer diameter) of the balloon 31 in the radial direction y1 is preferably the largest. The straight pipe section 34 preferably has approximately the same diameter in the longitudinal direction x1, but may have different diameters in the longitudinal direction x1. The proximal taper section 33 is located proximally of the straight pipe section 34 and connects to the proximal end of the straight pipe section 34. The distal taper section 35 is located distally of the straight pipe section 34 and connects to the distal end of the straight pipe section 34. It is preferable that the proximal taper section 33 and the distal taper section 35 are formed in a generally conical or truncated conical shape with their outer diameters tapering away from the straight tube section 34 .

[0041] The balloon 31 preferably further has a proximal sleeve portion 32 located proximal to the proximal taper portion 33 and a distal sleeve portion 36 located distal to the distal taper portion 35. The proximal sleeve portion 32 is located proximal to the proximal taper portion 33 and connected to the proximal end of the proximal taper portion 33. The distal sleeve portion 36 is located distal to the distal taper portion 35 and connected to the distal end of the distal taper portion 35. The proximal sleeve portion 32 and the distal sleeve portion 36 are preferably formed in a substantially cylindrical shape.

[0042] When a fluid is introduced into the balloon 31, the proximal tapered section 33, the straight tube section 34, and the distal tapered section 35 are sections that expand, whereas the proximal sleeve section 32 and the distal sleeve section 36 preferably do not expand. Since the proximal sleeve section 32 and the distal sleeve section 36 do not expand, it is possible to configure at least a portion of the proximal sleeve section 32 to be fixed to the distal end section of the outer resin tube 11, and at least a portion of the distal sleeve section 36 to be fixed to the inner resin tube 12.

[0043] The balloon 31 is preferably made of a resin, and more preferably made of a thermoplastic resin. By making the balloon 31 of a resin, it becomes easy to manufacture the balloon 31 by molding.

[0044] Examples of the resin constituting the balloon 31 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyamide resins such as polyphenylene sulfide resin, polyamide and polyamide elastomer, fluorine-based resins, silicone resins, and natural rubbers such as latex rubber. These may be used alone or in combination of two or more. Among them, polyamide resins, polyester resins, and polyurethane resins are preferably used as the resin constituting the balloon 31. In particular, from the viewpoint of thinning and flexibility of the balloon 31, it is preferable to use elastomer resins as the resin constituting the balloon 31. For example, among polyamide resins, examples of suitable materials for the balloon 31 include nylon 12 and nylon 11, and nylon 12 is preferably used because it is relatively easy to mold during blow molding. In addition, from the viewpoint of thinning and flexibility of the balloon 31, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used as the resin constituting the balloon 31. Among these, polyether ester amide elastomer is preferably used as the resin constituting the balloon 31 because it has high yield strength and the dimensional stability of the balloon 31 is good.

[0045] The catheter 1 is configured so that fluid is supplied to the inner cavity of the balloon 31 through the shaft 10, and the expansion and contraction of the balloon 31 can be controlled using an indeflator (a balloon pressurizer / depressurizer). The fluid may be a pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied to the inner cavity of the balloon 31 may be referred to as a "balloon expansion fluid."

[0046] When the catheter 1 is an over-the-wire type balloon catheter, it is preferable that the inflation lumen and the guidewire lumen extend to a hub 5 located on the proximal side, and that the proximal openings of each lumen are provided in a bifurcated hub 5.

[0047] The radiopaque markers 40 are disposed inside the balloon 31 and outside the inner resin tube 12. The radiopaque markers 40 include a first marker 41, a second marker 42, and a third marker 43. The radiopaque markers 40 can be confirmed under X-ray fluoroscopy. The catheter 1 may further have a radiopaque marker 40 different from the first marker 41, the second marker 42, and the third marker 43.

[0048] The shape of the radiopaque marker 40 is preferably tubular, and examples of such shapes include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross section with a notch in the tube, a coil shape with a wound wire, etc. The material constituting the radiopaque marker 40 may be, for example, a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt chromium alloy.

[0049] In the longitudinal direction x1, the third marker 43 is located between the first marker 41 and the second marker 42. That is, the first marker 41, the second marker 42, and the third marker 43 are arranged in the longitudinal direction x1 in the following order: first marker 41, third marker 43, second marker 42.

[0050] As shown in Figures 4 to 6, the X-ray imaging device 50 has a first field of view F1 in which the imaging field of view of the X-ray imaging device 50 includes a first marker 41, and a second field of view F2 in which the imaging field of view of the X-ray imaging device 50 includes a second marker 42, and the first field of view F1 may further include a third marker 43 in the imaging field of view of the X-ray imaging device 50, and the second field of view F2 in which the imaging field of view of the X-ray imaging device 50 does not include the first marker 41 or the third marker 43.

[0051] 4, in a first field of view F1 in which the first marker 41 is included in the imaging field of view of the X-ray imaging device 50, the third marker 43 may also be included in the imaging field of view of the X-ray imaging device 50. In the first field of view F1, the second marker 42 is not included in the imaging field of view of the X-ray imaging device 50. In other words, in the first field of view F1, at least the first marker 41 is included in the imaging field of view of the X-ray imaging device 50 and may also include the third marker 43, but the second marker 42 is not included. It is preferable that the first field of view F1 is such that the entire first marker 41 is included in the imaging field of view of the X-ray imaging device 50 and may include the entire third marker 43, and the entire second marker 42 is not included in the imaging field of view of the X-ray imaging device 50.

[0052] 5, in a second field of view F2 in which the second marker 42 is included in the imaging field of view of the X-ray imaging device 50, the first marker 41 and the third marker 43 are not included in the imaging field of view of the X-ray imaging device 50. That is, in the second field of view F2, at least the second marker 42 is included in the imaging field of view of the X-ray imaging device 50, but the first marker 41 and the third marker 43 are not included. It is preferable that the second field of view F2 is such that the entire second marker 42 is included in the imaging field of view of the X-ray imaging device 50, and the entire first marker 41 and the entire third marker 43 are not included in the imaging field of view of the X-ray imaging device 50.

[0053] As shown in Fig. 6, the X-ray imaging device 50 includes an X-ray irradiator 51 that irradiates X-rays and an X-ray detector 52 that detects the irradiated X-rays. A subject 53 such as a patient or an animal is placed between the X-ray irradiator 51 and the X-ray detector 52, and X-ray imaging is performed by irradiating X-rays from the X-ray irradiator 51 toward the subject 53 and detecting the X-rays that have passed through the subject 53 with the X-ray detector 52. In Fig. 6, the X-rays irradiated from the X-ray irradiator 51 toward the subject 53 are indicated by dashed arrows.

[0054] The X-ray imaging device 50 may have a configuration in which an X-ray irradiation unit 51 and an X-ray detection unit 52 are connected by an arm 54. The arm 54 may have a dolly 55. Furthermore, the X-ray imaging device 50 may have a bed 56 between the X-ray irradiation unit 51 and the X-ray detection unit 52 on which a subject 53 is placed.

[0055] The shape and size of the imaging field of the X-ray imaging device 50 depend on the shape and size of the X-ray detection unit 52, and are often almost the same. The shape of the X-ray detection unit 52 or the imaging field is preferably square or rectangular, and may be polygonal, circular, or elliptical. The size of the X-ray detection unit 52 or the imaging field varies depending on the subject 53, such as a body part of a patient or animal to be imaged, and the longitudinal length of the X-ray detection unit 52 or the imaging field is preferably 4 inches (10 cm) or more, more preferably 6 inches (15 cm) or more, and even more preferably 8 inches (20 cm) or more. The larger the X-ray detection unit 52, the wider the imaging field. The size of the X-ray detection unit 52 or the imaging field is preferably 20 inches (50 cm) or less in the longitudinal direction, more preferably 16 inches (40 cm) or less, and even more preferably 12 inches (30 cm) or less. The smaller the X-ray detection unit 52, the easier it is to perform high-definition imaging.

[0056] In the balloon catheter system, the first field of view F1 may further include the third marker 43 in the imaging field of the X-ray imaging device 50, and the second field of view F2 does not include the first marker 41 and the third marker 43 in the imaging field of the X-ray imaging device 50. Therefore, even if the balloon 31 has a length in the longitudinal direction x1 that is longer than the size of the field of view of the X-ray imaging device 50, it is possible to know which part of the balloon 31 is being viewed under X-ray fluoroscopy based on the number of X-ray-opaque markers 40 that are visible. Therefore, by using the X-ray imaging device 50, it is possible to check the balloon 31, the intravital lumen, the status of the procedure, and the like.

[0057] To explain this with a specific example, in the balloon catheter system as shown in Figures 1 to 3, the first field of view F1 is as shown in Figure 4, and the second field of view F2 is as shown in Figure 5. Under X-ray fluoroscopy, when two X-ray opaque markers 40 are visible as in the first field of view F1, it can be determined that the distal side of the balloon 31 of the balloon catheter 1 is being observed by the X-ray imaging device 50, and when only one X-ray opaque marker 40 is visible as in the second field of view F2, it can be determined that the proximal side of the balloon 31 of the balloon catheter 1 is being observed by the X-ray imaging device 50.

[0058] It is preferable that the second field of view F2 does not include other radiopaque markers 40 in the imaging field of the X-ray imaging device 50. In other words, it is preferable that in the second field of view F2, only the second marker 42 of the radiopaque markers 40 is reflected in the imaging field of the X-ray imaging device 50. In the second field of view F2, since the imaging field of the X-ray imaging device 50 does not include other radiopaque markers 40, it becomes easier to determine that the second marker 42 is being confirmed under X-ray fluoroscopy, and it becomes easier to understand which part of the balloon 31 is being observed.

[0059] It is preferable that the first marker 41 is located distal to the third marker 43, and the second marker 42 is located proximal to the third marker 43. That is, it is preferable that the first marker 41, the second marker 42, and the third marker 43 are arranged in the order of the first marker 41, the third marker 43, and the second marker 42 from the distal side to the proximal side of the balloon 31. Since the first marker 41 is located distal to the third marker 43 and the second marker 42 is located proximal to the third marker 43, if the first marker 41 and the third marker 43 are reflected in the imaging field of the X-ray imaging device 50 under X-ray fluoroscopy, it can be determined that the distal side of the balloon 31 is being viewed, and if the second marker 42 is reflected in the imaging field of the X-ray imaging device 50, it can be determined that the proximal side of the balloon 31 is being viewed. Therefore, it is easy to know which part of the balloon 31 is being visually recognized by the X-ray imaging device 50, and the state of the balloon 31 and the intravital lumen can be quickly and accurately grasped.

[0060] The balloon 31 has a straight tube section 34, a proximal tapered section 33 located proximal to the straight tube section 34, and a distal tapered section 35 located distal to the straight tube section 34. The straight tube section 34 is a region obtained by dividing the length L34 of the straight tube section 34 in the longitudinal direction x1 into three equal parts, and has a distal region Rd located on the most distal side, a proximal region Rp located on the most proximal side, and a central region Rc located proximal to the distal region Rd and distal to the proximal region Rp. It is preferable that the first marker 41 is arranged in the distal region Rd, the second marker 42 is arranged in the proximal region Rp, and the third marker 43 is arranged in the central region Rc. By arranging the first marker 41 in the distal region Rd, the second marker 42 in the proximal region Rp, and the third marker 43 in the central region Rc, it is possible to determine that the distal side of the balloon 31 is being viewed when the first marker 41 and the third marker 43 are visible in the imaging field of the X-ray imaging device 50 under X-ray fluoroscopy, and it is possible to determine that the proximal side of the balloon 31 is being viewed when the second marker 42 is visible in the imaging field of the X-ray imaging device 50. As a result, it is possible to quickly determine which part of the balloon 31 is being viewed by the X-ray imaging device 50, making it easier to grasp the state of the balloon 31 and the intravital lumen.

[0061] It is preferable that the first marker 41 is disposed at a location where the distal end 34d of the straight pipe section 34 is located, and the second marker 42 is disposed at a location where the proximal end 34p of the straight pipe section 34 is located. By disposing the first marker 41 at a location where the distal end 34d of the straight pipe section 34 is located, and the second marker 42 at a location where the proximal end 34p of the straight pipe section 34 is located, the positions of the distal end 34d and the proximal end 34p of the straight pipe section 34 of the balloon 31 can be confirmed under X-ray fluoroscopy, and the state of the straight pipe section 34 of the balloon 31 can be easily grasped.

[0062] The third marker 43 is preferably located distal to the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1. The length L31 of the balloon 31 refers to the length in the longitudinal direction x1 of the portion that expands when a fluid is introduced into the balloon 31. In other words, when the balloon 31 has a proximal taper portion 33, a straight tube portion 34, and a distal taper portion 35, the length L31 of the balloon 31 refers to the length from the proximal end of the proximal taper portion 33 to the distal end of the distal taper portion 35. Since the third marker 43 is located distal to the midpoint P1 of the length L31 of the balloon 31, the third marker 43 is disposed closer to the distal side of the balloon 31. Therefore, if the third marker 43 is reflected in the imaging field of the X-ray imaging device 50 under X-ray fluoroscopy, it is easy to determine that the distal side of the balloon 31 is being visually recognized.

[0063] The length L31 of the balloon 31 in the longitudinal direction x1 is preferably 100 mm or more, more preferably 150 mm or more, even more preferably 200 mm or more, and even more preferably 250 mm or more. The upper limit of the length L31 of the balloon 31 in the longitudinal direction x1 is not particularly limited, but may be, for example, 500 mm or less, 400 mm or less, or 300 mm or less.

[0064] The distance DP3 between the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1 and the third marker 43 is preferably smaller than the distance D343 between the distal end 34d of the straight tube portion 34 of the balloon 31 in the longitudinal direction x1 and the third marker 43. The distance DP3 between the midpoint P1 of the length L31 of the balloon 31 and the third marker 43 in the longitudinal direction x1 is the shortest distance from the midpoint P1 of the length L31 of the balloon 31 to the end of the third marker 43 closer to the midpoint P1 of the length L31 of the balloon 31. The distance D343 between the distal end 34d of the straight tube portion 34 of the balloon 31 and the third marker 43 in the longitudinal direction x1 is the shortest distance from the distal end 34d of the straight tube portion 34 of the balloon 31 to the end of the third marker 43 closer to the distal end 34d of the straight tube portion 34 of the balloon 31. In the balloon catheter 1 shown in Fig. 3, the distance DP3 from the midpoint P1 of the length L31 of the balloon 31 to the proximal end of the third marker 43 in the longitudinal direction x1 is preferably smaller than the distance D343 from the distal end 34d of the straight tube portion 34 of the balloon 31 to the distal end of the third marker 43. Since the distance DP3 between the midpoint P1 of the balloon 31 and the third marker 43 in the longitudinal direction x1 is smaller than the distance D343 between the distal end 34d of the straight tube portion 34 and the third marker 43, the third marker 43 is positioned near the center of the balloon 31 while being closer to the distal side of the balloon 31. As a result, the state of the central portion of the balloon 31 can also be confirmed under X-ray fluoroscopy.

[0065] The distance DP3 between the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1 and the third marker 43 is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less of the distance D343 between the distal end 34d of the straight tube portion 34 of the balloon 31 in the longitudinal direction x1 and the third marker 43. By setting the upper limit value of the ratio of the distance DP3 from the midpoint P1 of the balloon 31 to the third marker 43 in the longitudinal direction x1 and the distance D343 from the distal end 34d of the straight tube portion 34 to the third marker 43 within the above range, the third marker 43 is disposed in the center of the balloon 31, and by checking the third marker 43 under X-ray fluoroscopy, the state of the center of the balloon 31 can be easily checked. Moreover, the distance DP3 between the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1 and the third marker 43 is preferably 2% or more of the distance D343 between the distal end 34d of the straight tube portion 34 of the balloon 31 in the longitudinal direction x1 and the third marker 43, more preferably 4% or more, even more preferably 8% or more, and even more preferably 12% or more. By setting the lower limit of the ratio of the distance DP3 from the midpoint P1 of the balloon 31 to the third marker 43 in the longitudinal direction x1 and the distance D343 from the distal end 34d of the straight tube portion 34 to the third marker 43 within the above range, the third marker 43 can be separated from the midpoint P1 of the length L31 of the balloon 31, and when the third marker 43 is reflected in the imaging field of the X-ray imaging device 50, it is easy to determine that the distal side of the balloon 31 is visually recognized.

[0066] The distance DP3 between the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1 and the third marker 43 is preferably smaller than the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1. The distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is the shortest distance from the end of the first marker 41 closer to the third marker 43 to the end of the third marker 43 closer to the first marker 41. In the balloon catheter 1 shown in FIG. 3, the distance DP3 from the midpoint P1 of the length L31 of the balloon 31 to the proximal end of the third marker 43 in the longitudinal direction x1 is preferably smaller than the distance D13 from the proximal end of the first marker 41 to the distal end of the third marker 43. In the longitudinal direction x1, the distance DP3 between the midpoint P1 of the balloon 31 and the third marker 43 is smaller than the distance D13 between the first marker 41 and the third marker 43, so that the location where the third marker 43 is located is close to the midpoint P1 of the length L31 of the balloon 31. Therefore, it becomes possible to grasp the state of the balloon 31 and the intravital lumen at the center of the balloon 31 under X-ray fluoroscopy.

[0067] The distance DP3 between the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1 and the third marker 43 is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less of the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1. By setting the upper limit of the ratio of the distance DP3 from the midpoint P1 of the balloon 31 to the third marker 43 in the longitudinal direction x1 and the distance D13 between the first marker 41 and the third marker 43 within the above range, the third marker 43 is provided at a position close to the midpoint P1 of the length L31 of the balloon 31, and it becomes easier to check the condition of the center of the balloon 31 by checking the third marker 43 under X-ray fluoroscopy. Moreover, the distance DP3 between the midpoint P1 of the length L31 of the balloon 31 in the longitudinal direction x1 and the third marker 43 is preferably 3% or more of the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1, more preferably 6% or more, even more preferably 10% or more, and even more preferably 14% or more. By setting the lower limit of the ratio of the distance DP3 from the midpoint P1 of the balloon 31 to the third marker 43 in the longitudinal direction x1 and the distance D13 between the first marker 41 and the third marker 43 to the above range, the distance between the third marker 43 and the midpoint P1 of the length L31 of the balloon 31 can be increased, and it becomes easier to determine that the distal side of the balloon 31 is being visually recognized when the third marker 43 is reflected in the imaging field of view of the X-ray imaging device 50.

[0068] When the length L34 of the straight tube portion 34 of the balloon 31 is 200 mm or more and 400 mm or less, it is preferable that the distance DP3 from the midpoint P1 of the balloon 31 to the third marker 43 in the longitudinal direction x1 is 10 mm or more and 60 mm or less, and the distance D13 from the first marker 41 to the third marker 43 in the longitudinal direction x1 is 50 mm or more and 190 mm or less. By setting the distance DP3 from the midpoint P1 of the balloon 31 to the third marker 43 and the distance D13 from the first marker 41 to the third marker 43 within the above ranges, the first field of view F1 of the X-ray imaging device 50 is likely to include the first marker 41 and the third marker 43, making it easier to determine that the distal part of the balloon 31 is being viewed under X-ray fluoroscopy, and to easily confirm the condition of the central part of the balloon 31.

[0069] The distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably smaller than the distance D23 between the second marker 42 and the third marker 43 in the longitudinal direction x1. The distance D23 between the second marker 42 and the third marker 43 in the longitudinal direction x1 is the shortest distance from the end of the second marker 42 closer to the third marker 43 to the end of the third marker 43 closer to the second marker 42. In the longitudinal direction x1, the distance D13 between the first marker 41 and the third marker 43 is smaller than the distance D23 between the second marker 42 and the third marker 43, so that the first field of view F1 of the X-ray imaging device 50 includes the first marker 41 and the third marker 43, and the second field of view F2 does not include the first marker 41 and the third marker 43. Therefore, it is easy to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0070] The distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably 90% or less of the distance D23 between the second marker 42 and the third marker 43 in the longitudinal direction x1, more preferably 85% or less, even more preferably 80% or less, and even more preferably 75% or less. By setting the upper limit value of the ratio of the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 to the distance D23 between the second marker 42 and the third marker 43 in the longitudinal direction x1 within the above range, the first marker 41 and the third marker 43 can be easily included in the first field of view F1 of the X-ray imaging device 50 under X-ray fluoroscopy, and can be difficult to be included in the second field of view F2. In addition, the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably 10% or more of the distance D23 between the second marker 42 and the third marker 43 in the longitudinal direction x1, more preferably 20% or more, and even more preferably 30% or more. By setting the lower limit of the ratio between the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 and the distance D23 between the second marker 42 and the third marker 43 to the above range, it is easy to ensure a sufficient distance between the first marker 41 and the third marker 43, making it easier to distinguish between the first marker 41 and the third marker 43 in the first field of view F1 of the X-ray imaging device 50.

[0071] When the length L34 of the straight tube portion 34 of the balloon 31 is 200 mm or more and 400 mm or less, it is preferable that the distance D13 from the first marker 41 to the third marker 43 in the longitudinal direction x1 is 50 mm or more and 190 mm or less, and the distance D23 from the second marker 42 to the third marker 43 in the longitudinal direction x1 is 60 mm or more and 240 mm or less. By setting the distance D13 from the first marker 41 to the third marker 43 and the distance D23 from the second marker 42 to the third marker 43 within the above ranges, the first marker 41 and the third marker 43 are easily included in the first field of view F1 of the X-ray imaging device 50, and the first marker 41 and the third marker 43 are difficult to include in the second field of view F2, making it easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0072] The positions of the first marker 41, the second marker 42, and the third marker 43 relative to the balloon 31 may be different between the expanded state in which the balloon 31 is expanded and the contracted state in which the balloon 31 is contracted. Specifically, for example, in the expanded state of the balloon 31, the first marker 41 is disposed at a location where the distal end 34d of the straight tube portion 34 of the balloon 31 is located, the second marker 42 is disposed at a location where the proximal end 34p of the straight tube portion 34 of the balloon 31 is located, and the third marker 43 is disposed distal to the midpoint P1 of the length L31 of the balloon 31. In the contracted state of the balloon 31, the first marker 41 may be disposed proximal to the location where the distal end 34d of the straight tube portion 34 of the balloon 31 is located, the second marker 42 is disposed distal to the location where the proximal end 34p of the straight tube portion 34 of the balloon 31 is located, and the third marker 43 is disposed at the midpoint P of the length L31 of the balloon 31.

[0073] Furthermore, the positions of the first marker 41, the second marker 42, and the third marker 43 relative to the balloon 31 may be the same in an expanded state in which the balloon 31 is expanded and in a contracted state in which the balloon 31 is contracted. That is, for example, in the expanded state of the balloon 31, if the first marker 41 is disposed at a location where the distal end 34d of the straight tube portion 34 of the balloon 31 is located, the second marker 42 is disposed at a location where the proximal end 34p of the straight tube portion 34 of the balloon 31 is located, and the third marker 43 is disposed distal to the midpoint P1 of the length L31 of the balloon 31, then the first marker 41, the second marker 42, and the third marker 43 may be located at the same positions even in the contracted state of the balloon 31.

[0074] The multiple radiopaque markers 40 further include a fourth marker 44 located between the first marker 41 and the second marker 42 in the longitudinal direction x1, and a distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 is preferably smaller than a distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1. The distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 is the shortest distance from an end of the third marker 43 closer to the fourth marker 44 to an end of the fourth marker 44 closer to the third marker 43. In the longitudinal direction x1, the distance D34 between the third marker 43 and the fourth marker 44 is smaller than the distance D13 between the first marker 41 and the third marker 43, and therefore, two X-ray opaque markers 40 that are closer than the distance D13 between the first marker 41 and the third marker 43 are reflected in the imaging field of the X-ray imaging device 50 under X-ray fluoroscopy, and therefore, it can be determined that the third marker 43 and the fourth marker 44 are being imaged by the X-ray imaging device 50. Since the third marker 43 and the fourth marker 44 are reflected in the imaging field of the X-ray imaging device 50, it can be determined that the center of the balloon 31 is being viewed, and it can be easily understood which part of the balloon 31 is being viewed under X-ray fluoroscopy by the X-ray imaging device 50.

[0075] The distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 is preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less of the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1. By setting the upper limit of the ratio of the distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 to the distance D13 between the first marker 41 and the third marker 43 within the above range, it is easy to make the distance D34 between the third marker 43 and the fourth marker 44 sufficiently smaller than the distance D13 between the first marker 41 and the third marker 43, and it is easy to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy. Furthermore, the distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 is preferably 2% or more, more preferably 4% or more, and even more preferably 6% or more of the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1. By setting the lower limit of the ratio of the distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 to the distance D13 between the first marker 41 and the third marker 43 within the above range, a space is likely to be formed between the third marker 43 and the fourth marker 44, making it easier to see that what is being viewed under X-ray fluoroscopy is not one X-ray opaque marker 40 but two X-ray opaque markers 40, the third marker 43 and the fourth marker 44.

[0076] When the length L34 of the straight tube portion 34 of the balloon 31 is 200 mm or more and 400 mm or less, it is preferable that the distance D34 from the third marker 43 to the fourth marker 44 in the longitudinal direction x1 is 5 mm or more and 50 mm or less, and the distance D13 from the first marker 41 to the third marker 43 is 50 mm or more and 190 mm or less. By setting the distance D34 from the third marker 43 to the fourth marker 44 and the distance D13 from the first marker 41 to the third marker 43 within the above ranges, it is possible to easily determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0077] The distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably greater than the distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1. The distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1 is the shortest distance from the end of the first marker 41 closer to the fourth marker 44 to the end of the fourth marker 44 closer to the first marker 41. In the longitudinal direction x1, the distance D13 between the first marker 41 and the third marker 43 is greater than the distance D14 between the first marker 41 and the fourth marker 44, so that the first marker 41 and the fourth marker 44 can be brought closer to each other. As a result, the first field of view F1 of the X-ray imaging device 50 includes the first marker 41, the third marker 43, and the fourth marker 44, making it easier to distinguish the part of the balloon 31 viewed under X-ray fluoroscopy.

[0078] The distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably 1.025 times or more, more preferably 1.050 times or more, and even more preferably 1.075 times or more, of the distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1. By setting the lower limit of the ratio of the distance D13 between the first marker 41 and the third marker 43 to the distance D14 between the first marker 41 and the fourth marker 44 within the above range, the distance between the third marker 43 and the fourth marker 44 can be increased, and the third marker 43 and the fourth marker 44 can be easily distinguished under X-ray fluoroscopy, making it easy to recognize them as two X-ray opaque markers 40. Moreover, the distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably 1.5 times or less, more preferably 1.4 times or less, and even more preferably 1.3 times or less, of the distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1. By setting the upper limit value of the ratio of the distance D13 between the first marker 41 and the third marker 43 to the distance D14 between the first marker 41 and the fourth marker 44 within the above range, the third marker 43 can be brought closer to the first marker 41 and the fourth marker 44, and the first field of view F1 is likely to include the first marker 41, the third marker 43, and the fourth marker 44, making it easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0079] When the length L34 of the straight tube portion 34 of the balloon 31 is 200 mm or more and 400 mm or less, it is preferable that the distance D13 from the first marker 41 to the third marker 43 in the longitudinal direction x1 is 50 mm or more and 190 mm or less, and the distance D14 from the first marker 41 to the fourth marker 44 is 45 mm or more and 185 mm or less. By setting the distance D13 from the first marker 41 to the third marker 43 and the distance D14 from the first marker 41 to the fourth marker 44 within the above ranges, it becomes easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0080] The distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1 is preferably smaller than the distance D24 between the second marker 42 and the fourth marker 44 in the longitudinal direction x1. The distance D24 between the second marker 42 and the fourth marker 44 in the longitudinal direction x1 is the shortest distance from the end of the second marker 42 closer to the fourth marker 44 to the end of the fourth marker 44 closer to the second marker 42. In the longitudinal direction x1, the distance D14 between the first marker 41 and the fourth marker 44 is smaller than the distance D24 between the second marker 42 and the fourth marker 44, so that the fourth marker 44 is closer to the first marker 41 than the second marker 42, and the fourth marker 44 is more likely to be included in the first field of view F1 of the X-ray imaging device 50 and is less likely to be included in the second field of view F2. As a result, it is possible to easily determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0081] The distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1 is preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less of the distance D24 between the second marker 42 and the fourth marker 44 in the longitudinal direction x1. By setting the upper limit value of the ratio of the distance D14 between the first marker 41 and the fourth marker 44 and the distance D24 between the second marker 42 and the fourth marker 44 to the above range, the fourth marker 44 can be brought closer to the first marker 41, and the fourth marker 44 is more likely to be included in the first field of view F1 of the X-ray imaging device 50. In addition, the distance D14 between the first marker 41 and the fourth marker 44 in the longitudinal direction x1 is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more of the distance D24 between the second marker 42 and the fourth marker 44 in the longitudinal direction x1. By setting the lower limit of the ratio of the distance D14 between the first marker 41 and the fourth marker 44 and the distance D24 between the second marker 42 and the fourth marker 44 to the above range, the position where the fourth marker 44 is placed is likely to be the center of the balloon 31, making it easier to determine which part of the balloon 31 is visible under X-ray fluoroscopy.

[0082] When the length L34 of the straight tube portion 34 of the balloon 31 is 200 mm or more and 400 mm or less, it is preferable that the distance D14 from the first marker 41 to the fourth marker 44 in the longitudinal direction x1 is 45 mm or more and 185 mm or less, and the distance D24 from the second marker 42 to the fourth marker 44 is 40 mm or more and 200 mm or less. By setting the distance D14 from the first marker 41 to the fourth marker 44 and the distance D24 from the second marker 42 to the fourth marker 44 within the above ranges, the fourth marker 44 is more likely to be included in the first field of view F1 of the X-ray imaging device 50 and is less likely to be included in the second field of view F2, making it easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0083] The fourth marker 44 is preferably disposed in the central region Rc of the straight tube section 34 of the balloon 31. By disposing the fourth marker 44 in the central region Rc, it can be determined that the central region Rc of the straight tube section 34 of the balloon 31 is being viewed by checking the fourth marker 44 under X-ray fluoroscopy, making it easier to grasp which part of the balloon 31 is being viewed.

[0084] It is preferable that the first marker 41 is disposed in the distal region Rd of the straight tube section 34 of the balloon 31, the second marker 42 is disposed in the proximal region Rp of the straight tube section 34 of the balloon 31, and the third marker 43 and the fourth marker 44 are disposed in the central region Rc of the straight tube section 34 of the balloon 31. By disposing the first marker 41 in the distal region Rd, the second marker 42 in the proximal region Rp, and the third marker 43 and the fourth marker 44 in the central region Rc, it is easy to accurately grasp which part of the balloon 31 is being viewed under X-ray fluoroscopy, making it easier to perform the procedure.

[0085] Although not shown, a tip member is preferably provided at the distal end of the catheter 1. The tip member may be provided at the distal end of the balloon catheter as a member separate from the inner resin tube 12 and connected to the distal end of the balloon 31, or the inner resin tube 12 may extend distally beyond the distal end of the balloon 31 so that the distal end of the inner resin tube 12 functions as the tip member.

[0086] The core material 20 is disposed in the inner cavity of the shaft 10. By disposing the core material 20 in the inner cavity of the shaft 10, the rigidity of the shaft 10 can be increased, and the insertability of the catheter 1 can be improved. In addition, a force applied to the shaft 10 from the proximal side of the catheter 1 can be easily transmitted to the distal side of the shaft 10 through the core material 20, and the operability of the catheter 1 can be improved.

[0087] The core material 20 may have a hollow structure, and is preferably a tube or pipe having a cylindrical structure, a coil formed by winding one or more wires in a spiral shape, or a combination of these. The core material 20 having a hollow structure can increase the rigidity of the shaft 10 while ensuring appropriate flexibility, making it easy to deliver the catheter 1 to the treatment target site even in a curved body lumen such as a blood vessel. The core material 20 may also have a solid structure such as a wire. The core material 20 having a solid structure can increase the rigidity of the shaft 10, making it easy to insert the shaft 10 into a body lumen such as a blood vessel.

[0088] The core material 20 is preferably a linear member of a single wire or a stranded wire. As the core material 20, a thread formed from a metal wire such as stainless steel, carbon steel, or nickel-titanium alloy, or a polyolefin resin such as polyethylene or polypropylene, a polyamide resin such as nylon, a polyester resin such as PET, an aromatic polyetherketone resin such as PEEK, a polyetherpolyamide resin, a polyurethane resin, a polyimide resin, a fluorine resin such as PTFE, PFA, or ETFE, or a synthetic resin such as polyvinyl chloride resin can be used. The core material 20 may have a structure combining a metal material and a synthetic resin material, and for example, a braided metal wire and a synthetic resin wire, or a resin-coated metal wire can be used. The material constituting the core material 20 is preferably a metal wire, and more preferably stainless steel. By using the core material 20 as a metal wire, the strength of the core material 20 is increased, and the core material 20 is less likely to break or deform even if it is repeatedly bent.

[0089] It is preferable that the core material 20 has flexibility. Since the core material 20 has flexibility, it is possible to deform the core material 20 to conform to the shape of a vessel in a living body, such as a blood vessel, and the catheter 1 can also deform to conform to the shape of a curved lumen in a living body. In addition, it is preferable that the core material 20 has elasticity in order to maintain the shape of the core material 20.

[0090] In order to facilitate deformation on the distal side of the catheter 1, it is preferable that the core material 20 has a portion in which the rigidity decreases from the proximal side to the distal side, and it is even more preferable that at least a portion of the core material 20 in the longitudinal direction has a continuously decreasing rigidity from the proximal side to the distal side.

[0091] It is preferable that the core material 20 has at least a portion where the outer diameter of the core material 20, i.e., the thickness of the core material 20, is tapered from the proximal side to the distal side. By having at least a portion where the thickness of the core material 20 is tapered from the proximal side to the distal side, the force applied to the shaft 10 from the proximal side of the catheter 1 is easily transmitted to the distal side of the shaft 10, and the insertability of the catheter 1 can be improved. In addition, by having a portion where the thickness of the core material 20 is tapered, the cross-sectional area occupied by the core material 20 in the lumen of the shaft 10 can be reduced, making it possible to reduce the diameter of the shaft 10 and ensure the width of the lumen of the shaft 10.

[0092] As shown in Fig. 2, the core material 20 has a large diameter portion on the distal side where the core material 20 is thick, and a small diameter portion on the proximal side where the core material 20 is thin, and more preferably has a tapered portion between the large diameter portion and the small diameter portion where the core material 20 is tapered from the proximal side to the distal side. By having the core material 20 configured to have a large diameter portion, a small diameter portion, and a tapered portion, the difference in rigidity in the longitudinal direction of the core material 20 is unlikely to become large. As a result, it is possible to reduce the rigidity step in the shaft 10 and prevent kinking.

[0093] 7 is a cross-sectional view along the longitudinal direction of the core material 20 in another embodiment. As shown in FIG. 7, the core material 20 has a large diameter portion on the distal side where the core material 20 is thick, a small diameter portion on the proximal side where the core material 20 is thin, and a transition portion between the large diameter portion and the small diameter portion. In the cross-sectional view along the longitudinal direction x1, the transition portion is preferably configured such that one side of the central axis extending in the extension direction of the core material 20 is tapered, and the other side of the central axis is parallel to the extension direction of the core material 20. In other words, in the cross-sectional view along the longitudinal direction x1, the transition portion of the core material 20 is preferably configured to have a so-called one-sided tapered shape. Since the core material 20 has a large diameter portion, a small diameter portion, and a transition portion, the force applied to the proximal side of the catheter 1 is easily transmitted to the distal side by the core material 20. Furthermore, since the core material 20 has a transition section with one side tapered and the other side parallel to the extension direction of the core material 20, the volume occupied by the distal end of the core material 20 in the inner cavity of the shaft 10 can be reduced, and space can be secured in the inner cavity of the shaft 10 for placing other items such as tubes.

[0094] The cross-sectional shape of the core material 20 can be, for example, a circle, an oval, a polygon, a star, a crescent, a fan, or a combination of these. Note that the oval shape includes an ellipse, an egg, and a rounded rectangular shape. The cross-sectional shape of the core material 20 refers to the shape of a cross section perpendicular to the longitudinal direction when the core material 20 is in a straight state.

[0095] The proximal end 20p of the core material 20 is preferably located more proximal than the proximal end 11p of the outer resin tube 11. By having the proximal end 20p of the core material 20 located more proximal than the proximal end 11p of the outer resin tube 11, the rigidity of the shaft 10 on the proximal side of the catheter 1 can be increased.

[0096] The proximal end of the core material 20 is preferably fixed to the hub 5. By fixing the proximal end of the core material 20 to the hub 5, the fixing strength of the core material 20 is increased, and the core material 20 is less likely to move in the longitudinal direction x1 even when the shaft 10 is curved. Methods for fixing the proximal end of the core material 20 to the hub 5 include, for example, adhesion with an adhesive, fitting, and the like.

[0097] A position marker 60 may be provided on the shaft 10 in order to confirm the length to which the catheter 1 has been inserted into the body cavity. Methods for providing the position marker 60 on the shaft 10 include, for example, placing a marker on the outer resin tube 11 or the inner resin tube 12, partially coloring the outer surfaces of the outer resin tube 11 or the inner resin tube 12, or partially peeling off a coating applied to the outer surfaces of the outer resin tube 11 or the inner resin tube 12. The number of position markers 60 provided on the shaft 10 may be multiple. [Explanation of symbols]

[0098] 1: Balloon catheter 5: Hub 6:Fluid injection part 10: Shaft 11: Outer resin tube 11d: Distal end of outer resin tube 11p: Proximal end of outer resin tube 11a: Distal tube 11b: Proximal tube 12: Inner resin tube 12d: Distal end of inner resin tube 12p: Proximal end of inner resin tube 13: Opening 20: Core material 20d: Distal end of the core 20p: Proximal end of core 31: Balloon 32: Proximal sleeve part 33: Proximal taper 34: Straight pipe section 34d: Distal end of straight pipe section 34p: Proximal end of straight tube 35: Distal taper 36: Distal sleeve part 40: Radiopaque marker 41: First marker 42: Second marker 43: 3rd marker 44: 4th marker 50: X-ray imaging device 51:X-ray irradiation section 52: X-ray detector 53: Subject 60: Position marker F1: 1st field of view F2: 2nd field of view Rd: distal region Rc: Central area Rp: proximal region L31: Balloon length L34: Length of straight pipe P1: Midpoint of balloon length DP3: Distance between the midpoint of the balloon length and the third marker D13: Distance between 1st and 3rd markers D14: Distance between 1st and 4th markers D23: Distance between 2nd and 3rd markers D24: Distance between 2nd and 4th markers D34: Distance between 3rd and 4th markers D343: Distance between the distal end of the straight tube and the third marker

Claims

1. an outer resin tube having a longitudinal direction; an inner resin tube disposed in an inner cavity of the outer resin tube; a balloon disposed at a distal portion of the outer resin tube and capable of expanding and contracting; a balloon catheter having a first marker, a second marker, and a third marker, which are X-ray opaque markers arranged inside the balloon and outside the inner resin tube; and an X-ray imaging device capable of irradiating X-rays and capturing an image of the transmitted X-rays, the third marker is located between the first marker and the second marker in the longitudinal direction, the X-ray imaging device has a first field of view in which the first marker is included in an imaging field of view of the X-ray imaging device, and a second field of view in which the second marker is included in an imaging field of view of the X-ray imaging device, The first field of view may further include the third marker in an imaging field of view of the X-ray imaging device, A balloon catheter system in which the second field of view does not include the first marker and the third marker in the imaging field of view of the X-ray imaging device.

2. The balloon catheter system according to claim 1 , wherein the second field of view does not include other radiopaque markers in the imaging field of view of the X-ray imaging device.

3. the first marker is located distal to the third marker; The balloon catheter system according to claim 1 , wherein the second marker is located proximally relative to the third marker.

4. The balloon has a straight tube portion, a proximal tapered portion located proximally of the straight tube portion, and a distal tapered portion located distally of the straight tube portion, the straight pipe portion has a length in the longitudinal direction divided into three equal parts, the length being defined by a distal region located at the most distal side, a proximal region located at the most proximal side, and a central region located proximal to the distal region and distal to the proximal region; the first marker is disposed in the distal region; the second marker is disposed in the proximal region; The balloon catheter system of claim 1 , wherein the third marker is disposed in the central region.

5. the first marker is located at a location where a distal end of the straight tube section is located; The balloon catheter system according to claim 4 , wherein the second marker is disposed at a location where a proximal end of the straight tube portion is located.

6. The balloon catheter system according to claim 1 , wherein the third marker is located distal to a midpoint of the length of the balloon in the longitudinal direction.

7. 7. The balloon catheter system of claim 6, wherein a distance between a midpoint of the length of the balloon in the longitudinal direction and the third marker is smaller than a distance between the first marker and the third marker in the longitudinal direction.

8. 2. The balloon catheter system of claim 1, wherein the positions of the first marker, the second marker, and the third marker relative to the balloon are different in an expanded state in which the balloon is expanded and in a deflated state in which the balloon is deflated.

9. 2. The balloon catheter system of claim 1, wherein the positions of the first marker, the second marker, and the third marker relative to the balloon are the same in an expanded state in which the balloon is expanded and in a deflated state in which the balloon is deflated.

10. the plurality of radiopaque markers further includes a fourth marker located between the first marker and the second marker in the longitudinal direction; The balloon catheter system according to claim 1 , wherein a distance between the third marker and the fourth marker in the longitudinal direction is smaller than a distance between the first marker and the third marker in the longitudinal direction.

11. The balloon catheter system of claim 10 , wherein a distance between the first marker and the third marker in the longitudinal direction is greater than a distance between the first marker and the fourth marker in the longitudinal direction.

12. The balloon catheter system according to claim 10 , wherein a distance between the first marker and the fourth marker in the longitudinal direction is smaller than a distance between the second marker and the fourth marker in the longitudinal direction.

13. The balloon has a straight tube portion, a proximal tapered portion located proximally of the straight tube portion, and a distal tapered portion located distally of the straight tube portion, the straight pipe portion has a length in the longitudinal direction divided into three equal parts, the length being defined by a distal region located at the most distal side, a proximal region located at the most proximal side, and a central region located proximal to the distal region and distal to the proximal region; The balloon catheter system of claim 10 , wherein the fourth marker is disposed in the central region.

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