Catheter

Abstract

To provide a low-invasive catheter which is capable of confirming a state of a part having an X-ray impermeable marker arranged therein under fluoroscopy.SOLUTION: A catheter 1 includes: an outer side resin tube 11 having a long direction x1; an inner side resin tube 12 arranged in a lumen of the outer side resin tube 11; and a first marker 41, a second marker 42, and a third marker 43, being X-ray impermeable. The first marker 41, the second marker 42, and the third marker 43 have an outer shape in a cross section vertical to the long direction x1 having a long axis and a short axis. In the first marker 41, the second marker 42, and the third marker 43, orientation of the long axis of each outer shape in the cross section vertical to the long direction x1 is aligned.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a catheter. [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] In conventional catheters as described in Patent Documents 1 to 3, a radiopaque marker is provided on a treatment section of the catheter, such as a balloon, basket, or stent, which is used for treatment. This makes it possible to confirm the position of the treatment section in the lumen of the living body under X-ray fluoroscopy using an X-ray imaging device. In a lumen of the living body, a treatment section such as a balloon may be twisted, but with conventional catheters, it is difficult to confirm the detailed state of the treatment section in the lumen of the living body, such as the presence or absence of twisting of the treatment section. In a state in which a twist occurs in the treatment section of the catheter, there is a risk that it is impossible to confirm the progress of the procedure or to judge whether the procedure was successful or unsuccessful. As a specific example, when a balloon is twisted, the balloon may not be sufficiently expanded, resulting in insufficient expansion to a lesion such as a stenosis, or the balloon may be in a twisted state, and even though the balloon is not sufficiently expanded, it may be mistaken for an insufficient expansion pressure, and an excessive expansion fluid may be sent to the balloon, resulting in overexpansion and increased burden on the patient.

[0010] In addition, since it is difficult to check the detailed condition of the catheter treatment site by X-ray fluoroscopy with conventional catheters, intravascular ultrasound (IVUS) or optical coherence tomography (OCT) examinations are sometimes performed in parallel to check the progress and status of the treatment and to check the condition of the lumen wall in the body. However, in order to perform IVUS or OCT examinations, it is necessary to use additional instruments such as an examination catheter in addition to the catheter used for the treatment, which increases the procedure time and labor, and increases the burden on the surgeon and patient.

[0011] The present invention has been made in consideration of the above circumstances, and its object is to provide a minimally invasive catheter that allows the condition of the area in which an X-ray opaque marker is placed to be confirmed under X-ray fluoroscopy. [Means for solving the problem]

[0012] A catheter 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 first marker, a second marker, and a third marker that are radiopaque; the first marker, the second marker, and the third marker each have a major axis and a minor axis in a cross section perpendicular to the longitudinal direction; A catheter in which the first marker, the second marker, and the third marker have the long axes of their respective outlines aligned in a cross section perpendicular to the longitudinal direction. [2] The catheter described in [1], further comprising an expansion member disposed in the distal portion of the outer plastic tube. [3] The catheter described in [2], wherein the first marker, the second marker, and the third marker are positioned inside the expansion member and outside the inner plastic tube. [4] The inner resin tube has a first inner resin tube and a second inner resin tube, The catheter according to any one of [1] to [3], wherein the inner lumen of the first inner resin tube is disposed in parallel with the inner lumen of the second inner resin tube. [5] A catheter described in any of [1] to [4], in which the ratio of the length of the minor axis to the length of the major axis in the respective outlines of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction (length of minor axis / length of major axis) is 0.6 or greater and less than 1.0. [6] A catheter described in any of [1] to [5], wherein the difference in the length of the long axis at the respective contours of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction is less than 50% of the average value of the length of the long axis at the respective contours of the first marker, the second marker, and the third marker. [7] The expansion member is a balloon that can be expanded and contracted; 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 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 catheter according to [2] or [3], wherein the third marker is positioned in the central region. [8] the first marker is disposed at a location where a distal end of the straight tube portion is located; The catheter described in [7], wherein the second marker is positioned at a location where the proximal end of the straight tube portion is located. [9] A catheter as described in [7] or [8], wherein the third marker is located distal to the midpoint of the length of the balloon in the longitudinal direction.

[10] further comprising a fourth radiopaque marker, the fourth marker has an outer shape in a cross section perpendicular to the longitudinal direction having a major axis and a minor axis; A catheter described in any of [1] to [9], wherein the orientation of the long axis of the outline of the fourth marker in a cross section perpendicular to the longitudinal direction is aligned with the orientation of the long axis of the outline of each of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction.

[11] Further comprising an expansion member disposed at a distal portion of the outer resin tube, The expansion member is a balloon that can be expanded and contracted, 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 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 catheter according to

[10] , wherein the fourth marker is positioned in the central region.

[12] A catheter as described in

[10] or

[11] , in which the ratio of the length of the minor axis to the length of the major axis in the outline of the fourth marker in a cross section perpendicular to the longitudinal direction (length of minor axis / length of major axis) is 0.6 or greater and less than 1.0.

[13] A catheter described in any of

[10] to

[12] , wherein the length of the major axis of the fourth marker in a cross section perpendicular to the longitudinal direction is 50% or more and 150% or less of the average length of the major axis of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction. Effect of the Invention

[0013] According to the catheter, the first, second, and third markers, which are radiopaque, have a major axis and a minor axis in the cross section perpendicular to the longitudinal direction, and the major axes of the first, second, and third markers are aligned in the cross section perpendicular to the longitudinal direction, so that when the sizes and shapes of the markers are different under X-ray fluoroscopy, it can be determined that a twist has occurred in the portion of the catheter where the first, second, and third markers are arranged. As a result, the condition of the portion of the catheter where the markers are arranged can be confirmed by X-ray fluoroscopy, making the catheter a minimally invasive catheter. [Brief description of the drawings]

[0014] [Figure 1] 1 illustrates a side view of a catheter according to an embodiment of the present invention. [Diagram 2] 2 illustrates a longitudinal cross-sectional view of the catheter shown in FIG. 1. [Diagram 3]2 illustrates an enlarged view of the distal portion of the catheter shown in FIG. 1. [Figure 4] 4 shows a cross-sectional view of the catheter shown in FIG. 1 along line IV-IV. [Diagram 5] 2 shows a VV cross-sectional view of the catheter shown in FIG. 1. [Figure 6] 6 shows a cross-sectional view of the catheter shown in FIG. 1 along line VI-VI. [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

[0015] 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.

[0016] A catheter according to an embodiment of the present invention has an outer resin tube having a longitudinal direction, an inner resin tube disposed in the lumen of the outer resin tube, and first, second, and third markers that are opaque to X-rays, the first, second, and third markers having major and minor axes in their outlines in a cross section perpendicular to the longitudinal direction, and the long axes of the first, second, and third markers are aligned in the same direction.

[0017] Hereinafter, a balloon catheter according to an embodiment of the present invention will be described with reference to Figs. 1 to 6. Fig. 1 is a side view of a catheter according to an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of the catheter, and Fig. 3 is an enlarged view of a distal portion of the catheter, which is an enlarged side view of the distal portion of the catheter. Fig. 4 is a IV-IV cross-sectional view of the catheter, which is a cross-sectional view perpendicular to the longitudinal direction at a portion where a first marker is arranged. Fig. 5 is a VV cross-sectional view of the catheter, which is a cross-sectional view perpendicular to the longitudinal direction at a portion where a second marker is arranged. Fig. 6 is a VI-VI cross-sectional view of the catheter, which is a cross-sectional view perpendicular to the longitudinal direction at a portion where a third marker is arranged.

[0018] As shown in Figures 1 to 3, the catheter 1 has an outer resin tube 11 having a longitudinal direction x1, an inner resin tube 12 arranged in the inner cavity of the outer resin tube 11, and a first marker 41, a second marker 42, and a third marker 43 that are opaque to X-rays.

[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] The catheter 1 has a first marker 41, a second marker 42, and a third marker 43 that are radiopaque. The first marker 41, the second marker 42, and the third marker 43 can be confirmed under X-ray fluoroscopy. The catheter 1 may further have a radiopaque marker 40 that is different from the first marker 41, the second marker 42, and the third marker 43.

[0034] The shape of the radiopaque marker 40 including the first marker 41, the second marker 42, and the third marker 43 is preferably tubular, and examples of such shapes include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross section with a slit in the tube, and a coil shape with a wound wire. 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.

[0035] As shown in Figures 4 to 6, the first marker 41, the second marker 42, and the third marker 43 have outlines in a cross section perpendicular to the longitudinal direction x1 that have major axes A1a, A2a, A3a and minor axes A1b, A2b, A3b, and the first marker 41, the second marker 42, and the third marker 43 have the major axes A1a, A2a, A3a of their respective outlines in a cross section perpendicular to the longitudinal direction x1 that are aligned with each other.

[0036] The major axis of the marker's outline in a cross section perpendicular to the longitudinal direction x1 is the line segment that passes through the centroid of the marker's outline and connects any two points on the edge of the marker's outline, and has the longest length. The minor axis of the marker's outline in a cross section perpendicular to the longitudinal direction x1 is the line segment that passes through the centroid of the marker's outline and connects any two points on the edge of the marker's outline, and has the shortest length.

[0037] The orientations of the long axes A1a, A2a, A3a of the outer shapes of each of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 are considered to be aligned when, in two X-ray opaque markers 40 among the first marker 41, the second marker 42, and the third marker 43, the angle formed by the long axes A1a, A2a, A3a of the outer shapes of each of the X-ray opaque markers 40 in a cross section perpendicular to the longitudinal direction x1 is 30 degrees or less. Specifically, for example, when the angle between the long axis A1a of the contour of the first marker 41 in a cross section perpendicular to the longitudinal direction x1 and the long axis A2a of the contour of the second marker 42 in a cross section perpendicular to the longitudinal direction x1 is 30 degrees or less, it is determined that the orientations of the long axes A1a, A2a of the contours of the first marker 41 and the second marker 42, respectively, are aligned.

[0038] In other words, the alignment of the orientations of the long axes A1a, A2a, A3a of the contours of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 means that, as shown in Figures 4 to 6, in a cross section perpendicular to the longitudinal direction x1, the angle formed by the long axis A1a of the contour of the first marker 41 and the long axis A2a of the contour of the second marker 42, the angle formed by the long axis A1a of the contour of the first marker 41 and the long axis A3a of the contour of the third marker 43, and the angle formed by the long axis A2a of the contour of the second marker 42 and the long axis A3a of the contour of the third marker 43 are all 30 degrees or less.

[0039] The first marker 41, the second marker 42, and the third marker 43 are configured so that the directions of the long axes A1a, A2a, and A3a of the respective outer shapes in a cross section perpendicular to the longitudinal direction x1 are aligned. Therefore, when the sizes and shapes of the first marker 41, the second marker 42, and the third marker 43 are different under X-ray fluoroscopy, it can be determined that a twist has occurred in the part of the catheter 1 where the first marker 41, the second marker 42, and the third marker 43 are provided. If the catheter 1 is in a state where a twist has occurred, it may be impossible to check the progress of the procedure under X-ray fluoroscopy or to determine whether the procedure has been successful. Since it is possible to determine the presence or absence of a twist in the part of the catheter 1 where the first marker 41, the second marker 42, and the third marker 43 are provided under X-ray fluoroscopy, there is no need to use a separate instrument for performing an IVUS or OCT examination to determine the state of the catheter 1 in the lumen of the living body, and the procedure time and the effort required for the procedure can be reduced, resulting in a minimally invasive catheter 1.

[0040] Furthermore, even if the orientation of the long axes A1a, A2a, A3a of the outer shape is aligned, and the angle between the long axes A1a, A2a, A3a of the outer shape of each X-ray opaque marker 40 of two of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 is 45 degrees or less, it is possible to determine under X-ray fluoroscopy whether or not a large twist has occurred in the portion of the catheter 1 where the first marker 41, the second marker 42, and the third marker 43 are located when the sizes and shapes of the first marker 41, the second marker 42, and the third marker 43 are different. In order to detect even small twists in the portions of the catheter 1 where the first marker 41, the second marker 42, and the third marker 43 are provided, it is preferable to consider the orientation of the long axes A1a, A2a, A3a of the outer shape of each of the first marker 41, the second marker 42, and the third marker 43 to be aligned when the angle formed by the long axes A1a, A2a, A3a of the outer shape of each of the X-ray opaque markers 40 in a cross section perpendicular to the longitudinal direction x1 is 30 degrees or less.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The catheter 1 preferably has a treatment section disposed at the distal part of the outer resin tube 11. The treatment section is for performing treatment on a target site such as a lesion in a lumen within a living body. Examples of the treatment section include an expansion member such as a balloon, stent, or basket, an electrode for measuring an intracardiac potential or passing a high-frequency current, and a drug holding section for releasing a drug.

[0048] Among them, it is preferable that the catheter 1 further has an expansion member 30 disposed at the distal portion of the outer resin tube 11. Examples of the expansion member 30 include a balloon, a stent, and a basket. In a procedure using the catheter 1 having the expansion member 30, if the expansion member 30 is twisted, the expansion member 30 may not be sufficiently expanded, resulting in insufficient expansion of the lesion, or the expansion member 30 may be twisted and therefore unable to be sufficiently expanded, but the expansion pressure may be mistakenly considered to be insufficient, leading to overexpansion, resulting in more expansion fluid than necessary. Since the catheter 1 of the present invention has the expansion member 30, the presence or absence of twisting of the expansion member 30 can be confirmed under X-ray fluoroscopy, making it possible to prevent insufficient expansion or overexpansion by the expansion member 30.

[0049] The expansion member 30 is preferably a long object. Specifically, the length of the expansion member 30 in the longitudinal direction x1 is preferably 10 cm or more, more preferably 15 cm or more, even more preferably 20 cm or more, and even more preferably 25 cm or more. Since the expansion member 30 is a long object, even if the expansion member 30 is a long object that is prone to twisting, the presence or absence of twisting can be confirmed under X-ray fluoroscopy with the catheter 1 of the present invention, making it easier to reliably perform a minimally invasive procedure. The upper limit of the length of the expansion member 30 in the longitudinal direction x1 is not particularly limited, but can be, for example, 50 cm or less, 40 cm or less, or 30 cm or less.

[0050] It is more preferable that the expansion member 30 is a balloon 31. That is, it is preferable that the catheter 1 has a balloon 31 disposed in the distal portion of the outer resin tube 11. When the expansion member 30 is a balloon 31, it is possible to easily and efficiently expand a target site such as a lesion.

[0051] 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 .

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] When the catheter 1 has a balloon 31, the catheter 1 is configured so that a 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."

[0057] 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.

[0058] When the catheter 1 has a balloon 31, although not shown, it is preferable that a tip member is provided at the distal end of the catheter 1. The tip member may be provided at the distal end of the balloon catheter by being connected to the distal end of the balloon 31 as a member separate from the inner resin tube 12, 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The proximal end 20p of the core material 20 is preferably located closer to the proximal side than the proximal end 11p of the outer resin tube 11. By having the proximal end 20p of the core material 20 located closer to the proximal side 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.

[0069] 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.

[0070] The first marker 41, the second marker 42, and the third marker 43 are preferably arranged inside the expansion member 30 and outside the inner resin tube 12. By arranging the first marker 41, the second marker 42, and the third marker 43 inside the expansion member 30 and outside the inner resin tube 12, it is possible to check under X-ray fluoroscopy whether or not the expansion member 30 is twisted, and it is also possible to make it difficult to hinder the expansion of the expansion member 30.

[0071] Although not shown, the inner resin tube 12 may have a first inner resin tube and a second inner resin tube, and the inner cavity of the first inner resin tube may be arranged in parallel with the inner cavity of the second inner resin tube.

[0072] The ratio (length of minor axis A2 / length of major axis A1) of the lengths LA1b, LA2b, LA3b of the minor axes A1b, A2b, A3b to the lengths LA1a, LA2a, LA3a of the major axes A1a, A2a, A3a in the outlines of the first marker 41, the second marker 42, and the third marker 43 in the cross section perpendicular to the longitudinal direction x1 is preferably 0.6 or more and less than 1.0. That is, in each of the first marker 41, the second marker 42, and the third marker 43, the ratio of the lengths LA1b, LA2b, LA3b of the minor axes A1b, A2b, A3b to the lengths LA1a, LA2a, LA3a of the major axes A1a, A2a, A3a in the outlines of the respective X-ray impermeable markers 40 in the cross section perpendicular to the longitudinal direction x1 is preferably 0.6 or more and less than 1.0. By having the ratio of the lengths LA1b, LA2b, LA3b of the minor axes A1b, A2b, A3b to the lengths LA1a, LA2a, LA3a of the major axes A1a, A2a, A3a in the respective external shapes of the first marker 41, the second marker 42, and the third marker 43 be 0.6 or more and less than 1.0, it becomes easier to ensure the width of the lumen in the portion where the first marker 41, the second marker 42, and the third marker 43 are arranged of the catheter 1. Therefore, it becomes easier to feed articles such as a guidewire or fluid inside the portion where the first marker 41, the second marker 42, and the third marker 43 are arranged.

[0073] The ratio of the length LA1b, LA2b, LA3b of the minor axis A1b, A2b, A3b to the length LA1a, LA2a, LA3a of the major axis A1a, A2a, A3a in the cross section perpendicular to the longitudinal direction x1 of each of the first marker 41, the second marker 42, and the third marker 43 is preferably 0.55 or more, more preferably 0.60 or more, even more preferably 0.65 or more, and even more preferably 0.70 or more. By setting the lower limit of the ratio of the length LA1b, LA2b, LA3b of the minor axis A1b, A2b, A3b to the length LA1a, LA2a, LA3a of the major axis A1a, A2a, A3a of each of the radiopaque markers 40 to the length LA1a, LA2a, LA3a of the major axis A1a, A2a, A3a of each of the radiopaque markers 40 within the above range, it becomes easier to ensure a large width of the lumen of the radiopaque marker 40. In addition, the ratio of the length LA1b, LA2b, LA3b of the minor axis A1b, A2b, A3b to the length LA1a, LA2a, LA3a of the major axis A1a, A2a, A3a in the cross section perpendicular to the longitudinal direction x1 in the respective outer shapes of the first marker 41, the second marker 42, and the third marker 43 is preferably less than 1.0, more preferably 0.95 or less, and even more preferably 0.90 or less. By setting the upper limit value of the ratio of the length LA1b, LA2b, LA3b of the minor axis A1b, A2b, A3b to the length LA1a, LA2a, LA3a of the major axis A1a, A2a, A3a of each radiopaque marker 40 within the above range, it is possible to easily determine whether or not a twist has occurred in the portion where the radiopaque marker 40 is provided under X-ray fluoroscopy.

[0074] It is preferable that the difference between the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 is 50% or less of the average value of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1. In other words, it is preferable that the value of each of the difference between the length LA1a of the long axis A1a at the outline of the first marker 41 and the length LA2a of the long axis A2a at the outline of the second marker 42 in a cross section perpendicular to the longitudinal direction x1, the difference between the length LA1a of the long axis A1a at the outline of the first marker 41 and the length LA3a of the long axis A3a at the outline of the third marker 43, and the difference between the length LA2a of the long axis A2a at the outline of the second marker 42 and the length LA3a of the long axis A3a at the outline of the third marker 43 is 50% or less of the average value of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the outlines of the first marker 41, the second marker 42, and the third marker 43, respectively, in a cross section perpendicular to the longitudinal direction x1. The difference between the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outer shapes of the first marker 41, the second marker 42, and the third marker 43 is 50% or less of the average value of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outer shapes of the first marker 41, the second marker 42, and the third marker 43, so that the sizes of the first marker 41, the second marker 42, and the third marker 43 are approximately the same. As a result, it is possible to easily determine the presence or absence of twisting of the catheter 1 by comparing the sizes of the respective radiopaque markers 40 under X-ray fluoroscopy.

[0075] The difference in the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 is preferably 50% or less of the average value of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1, more preferably 45% or less, and even more preferably 40% or less. By setting the upper limit value of the ratio between the difference in the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 and the average values ​​of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 to the above range, the sizes of the first marker 41, the second marker 42, and the third marker 43 tend to be similar. In addition, the lower limit of the ratio between the difference in lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 and the average value of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a at the respective outlines of the first marker 41, the second marker 42, and the third marker 43 is not particularly limited, but can be, for example, 0% or more.

[0076] When the catheter 1 has an expansion member 30, the expansion member 30 is a balloon 31 that is capable of expanding and contracting, and the balloon 31 has a straight tube portion 34, a proximal tapered portion 33 located proximal to the straight tube portion 34, and a distal tapered portion 35 located distal to the straight tube portion 34, and the straight tube portion 34 has a length L34 of the straight tube portion 34 in the longitudinal direction x1 divided 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, and 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, the distal region Rd, central region Rc, and proximal region Rp of the straight tube section 34 of the balloon 31 can be confirmed under X-ray fluoroscopy, making it possible to determine whether or not the balloon 31 is twisted in each region.

[0077] 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, respectively, 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 position of the twist generated in the balloon 31 can be easily grasped in detail.

[0078] 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, it is possible to confirm the state of the distal side of the midpoint P1 of the length L31 of the balloon 31 under X-ray fluoroscopy. The distal portion of the balloon 31 is farther from the hand side of the catheter 1 than the proximal portion of the balloon 31, and therefore tends to be more easily twisted than the proximal portion of the balloon 31. By locating the third marker 43 distal to the midpoint P1 of the length L31 of the balloon 31, it becomes easier to determine twisting in the distal portion of the balloon 31, which is prone to twisting.

[0079] 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 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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 80 mm or more and 180 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, it becomes easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0084] 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, making it easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0085] The distance D13 between the first marker 41 and the third marker 43 in the longitudinal direction x1 is preferably 90% or less, more preferably 85% or less, even more preferably 80% or less, and even more preferably 75% or less of the distance D23 between the second marker 42 and the third marker 43 in the longitudinal direction x1. By setting the upper limit 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, it is possible to easily determine which part of the balloon 31 is being visually recognized under X-ray fluoroscopy. 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, more preferably 20% or more, and even more preferably 30% or more of the distance D23 between the second marker 42 and the third marker 43 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 in the longitudinal direction x1 to the distance D23 between the second marker 42 and the third marker 43 within the above range, it becomes easier 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 under X-ray fluoroscopy.

[0086] 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, it becomes easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0087] The catheter 1 further includes a fourth marker 44 that is radiopaque, and the fourth marker 44 has a long axis and a short axis in a cross section perpendicular to the longitudinal direction x1, and it is preferable that the orientation of the long axis of the outline of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is aligned with the orientation of the long axes A1a, A2a, A3a of the outlines of the first marker 41, the second marker 42, and the third marker 43, respectively, in a cross section perpendicular to the longitudinal direction x1.

[0088] The orientation of the long axis of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is aligned with the orientation of the long axes A1a, A2a, A3a of the respective contours of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 when the angle between the long axes of the contours of each X-ray opaque marker 40 in a cross section perpendicular to the longitudinal direction x1 between the fourth marker 44 and the first marker 41, between the fourth marker 44 and the second marker 42, and between the fourth marker 44 and the third marker 43 is 30 degrees or less. In other words, the orientation of the long axis of the outline of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is aligned with the orientation of the long axes A1a, A2a, A3a of the outlines of the first marker 41, the second marker 42, and the third marker 43, which means that in a cross section perpendicular to the longitudinal direction x1, the angle between the long axis of the outline of the fourth marker 44 and the long axis A1a of the outline of the first marker 41, the angle between the long axis of the outline of the fourth marker 44 and the long axis A2a of the outline of the second marker 42, and the angle between the long axis of the outline of the fourth marker 44 and the long axis A3a of the outline of the third marker 43 are all 30 degrees or less.

[0089] Since the orientation of the long axis of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is aligned with the orientation of the long axes A1a, A2a, A3a of the respective outlines of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1, it becomes possible to determine the presence or absence of twisting at the location where the fourth marker 44 of the catheter 1 is located under X-ray fluoroscopy, making it easier to check the condition of the catheter 1 in the intravital lumen.

[0090] As with the first marker 41, the second marker 42, and the third marker 43 described above, when the angle between the long axis of the outline of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 and the long axes A1a, A2a, A3a of the outlines of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1 is 45 degrees or less, it is possible to determine whether or not the catheter 1 is significantly twisted under X-ray fluoroscopy even if the directions of the long axes of the outlines are aligned.

[0091] The shape of the fourth marker 44 may be the same as those listed as the shapes of the radiopaque marker 40 including the first marker 41, the second marker 42, and the third marker 43. In addition, the material constituting the fourth marker 44 may be the same radiopaque substance as those listed as the materials constituting the radiopaque marker 40.

[0092] When the catheter 1 has a balloon 31, 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 becomes easier to check the presence or absence of twisting in the central region Rc of the straight tube section 34 of the balloon 31 by checking the fourth marker 44 under X-ray fluoroscopy.

[0093] When the catheter 1 has a balloon 31, 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 determine under X-ray fluoroscopy which part of the straight tube section 34 of the balloon 31 is twisted, making it easier to perform the procedure.

[0094] The ratio of the minor axis length to the major axis length in the outer shape of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 (minor axis length / major axis length) is preferably 0.6 or more and less than 1.0. When the ratio of the minor axis length to the major axis length in the outer shape of the fourth marker 44 is 0.6 or more and less than 1.0, it becomes easier to ensure a wide inner cavity of the fourth marker 44. Therefore, it becomes easier to pass objects such as a guidewire or fluid inside the portion where the fourth marker 44 is arranged.

[0095] The ratio of the length of the minor axis to the length of the major axis in the outline of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is preferably 0.55 or more, more preferably 0.60 or more, even more preferably 0.65 or more, and even more preferably 0.70 or more. By setting the lower limit of the ratio of the length of the minor axis to the length of the major axis in the outline of the fourth marker 44 to the above range, it is possible to easily ensure a wide inner cavity of the fourth marker 44. In addition, the ratio of the length of the minor axis to the length of the major axis in the outline of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is preferably less than 1.0, more preferably 0.95 or less, and even more preferably 0.90 or less. By setting the upper limit of the ratio of the length of the minor axis to the length of the major axis in the outline of the fourth marker 44 to the above range, it is possible to easily determine the presence or absence of twisting in the part where the fourth marker 44 is provided under X-ray fluoroscopy.

[0096] The length of the major axis of the outer shape of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is preferably 50% to 150% of the average value of the lengths LA1a, LA2a, and LA3a of the major axes A1a, A2a, and A3a of the outer shapes in cross sections perpendicular to the longitudinal direction x1 of the first marker 41, the second marker 42, and the third marker 43. It is more preferable that the length of the major axis of the outer shape of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is 50% to 150% of the length LA1a of the major axis A1a of the outer shape in a cross section perpendicular to the longitudinal direction x1 of the first marker 41, the length LA2a of the major axis A2a of the outer shape in a cross section perpendicular to the longitudinal direction x1 of the second marker 42, and the length LA3a of the major axis A3a of the outer shape in a cross section perpendicular to the longitudinal direction x1 of the third marker 43. The length of the major axis of the outer shape of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is 50% or more and 150% or less of the average value of the lengths LA1a, LA2a, LA3a of the major axes A1a, A2a, A3a of the outer shapes of the first marker 41, the second marker 42, and the third marker 43, so that the size of the fourth marker 44 is approximately the same as the sizes of the first marker 41, the second marker 42, and the third marker 43. Therefore, by comparing the sizes of the respective radiopaque markers 40 under X-ray fluoroscopy, it can be easily determined whether or not the catheter 1 is twisted.

[0097] The length of the major axis of the outer shape of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is preferably 50% or more, more preferably 55% or more, and even more preferably 60% or more of the average of the lengths LA1a, LA2a, and LA3a of the major axes A1a, A2a, and A3a of the outer shapes of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1. The length of the major axis of the outer shape of the fourth marker 44 in a cross section perpendicular to the longitudinal direction x1 is preferably 150% or less, more preferably 145% or less, and even more preferably 140% or less of the average of the lengths LA1a, LA2a, and LA3a of the major axes A1a, A2a, and A3a of the outer shapes of the first marker 41, the second marker 42, and the third marker 43 in a cross section perpendicular to the longitudinal direction x1. By setting the lower and upper limits of the ratio between the length of the long axis of the outline of the fourth marker 44 and the average values ​​of the lengths LA1a, LA2a, LA3a of the long axes A1a, A2a, A3a of the outlines of the first marker 41, the second marker 42, and the third marker 43, respectively, within the above range, the size of the fourth marker 44 tends to be close to the sizes of the first marker 41, the second marker 42, and the third marker 43.

[0098] The distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 is preferably smaller than the 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 the end of the third marker 43 closer to the fourth marker 44 to the end of the fourth marker 44 closer to the third marker 43. Since the distance D34 between the third marker 43 and the fourth marker 44 in the longitudinal direction x1 is smaller than the distance D13 between the first marker 41 and the third marker 43, two X-ray-opaque markers 40 closer to each other 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 it can be determined that the third marker 43 and the fourth marker 44 are imaged by the X-ray imaging device 50. Because the third marker 43 and the fourth marker 44 are visible in the imaging field of view of the X-ray imaging device 50, it can be determined that the center of the balloon 31 is being viewed, making it easier to understand which part of the balloon 31 is being viewed under X-ray fluoroscopy with the X-ray imaging device 50.

[0099] 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.

[0100] 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.

[0101] 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. Since 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 in the longitudinal direction x1, the first marker 41 and the fourth marker 44 can be brought closer to each other, and the portion of the balloon 31 viewed under X-ray fluoroscopy can be easily identified.

[0102] 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 of the ratio of the distance D13 between the first marker 41 and the third marker 43 and 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, making it easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0103] 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.

[0104] 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. As a result, it is possible to easily determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0105] 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 of the ratio of the distance D14 between the first marker 41 and the fourth marker 44 to the distance D24 between the second marker 42 and the fourth marker 44 within the above range, the fourth marker 44 can be brought closer to the first marker 41. Moreover, 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.

[0106] 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 30 mm or more and 190 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, it becomes easier to determine which part of the balloon 31 is being viewed under X-ray fluoroscopy.

[0107] 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]

[0108] 1: 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 30: Expansion member 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 60: Position marker A1a: Long axis of the outline of the first marker A1b: Short axis of the outline of the first marker A2a: Long axis of the outline of the second marker A2b: Minor axis of the outline of the second marker A3a: Long axis of the outline of the third marker A3b: Short axis of the outline of the third marker Rd: distal region Rc: Central area Rp: proximal region LA1a: Length of the major axis of the first marker LA1b: Length of the minor axis of the outline of the first marker LA2a: Length of the major axis of the outline of the second marker LA2b: Length of the minor axis of the outline of the second marker LA3a: Length of the major axis of the third marker LA3b: Length of the minor axis of the third marker 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 first marker, a second marker, and a third marker that are radiopaque; the first marker, the second marker, and the third marker each have a major axis and a minor axis in a cross section perpendicular to the longitudinal direction; A catheter in which the first marker, the second marker, and the third marker have the major axes of their respective outlines aligned in a cross section perpendicular to the longitudinal direction.

2. The catheter of claim 1 further comprising an expansion member disposed in a distal portion of the outer plastic tube.

3. The catheter according to claim 2 , wherein the first marker, the second marker, and the third marker are disposed inside the expansion member and outside the inner resin tube.

4. The inner resin tube has a first inner resin tube and a second inner resin tube, The catheter according to claim 1 , wherein the inner lumen of the first inner resin tube is disposed parallel to the inner lumen of the second inner resin tube.

5. The catheter according to claim 1, wherein the ratio of the length of the minor axis to the length of the major axis (minor axis length / major axis length) of the outline of each of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction is 0.6 or greater and less than 1.

0.

6. The catheter of claim 1, wherein a difference in the length of the major axis at the respective contours of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction is 50% or less of an average value of the length of the major axis at the respective contours of the first marker, the second marker, and the third marker.

7. The expansion member is a balloon that can be expanded and contracted, 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 catheter of claim 2 , wherein the third marker is disposed in the central region.

8. the first marker is located at a location where a distal end of the straight tube section is located; The catheter of claim 7 , wherein the second marker is disposed at a location where a proximal end of the straight tube portion is located.

9. The catheter according to claim 7 , wherein the third marker is located distal to a midpoint of the length of the balloon in the longitudinal direction.

10. further comprising a radiopaque fourth marker; The fourth marker has an outer shape in a cross section perpendicular to the longitudinal direction having a major axis and a minor axis, The catheter of claim 1, wherein the orientation of the long axis of the outline of the fourth marker in a cross section perpendicular to the longitudinal direction is aligned with the orientation of the long axis of each of the outlines of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction.

11. and an expansion member disposed at a distal portion of the outer plastic tube, The expansion member is a balloon that can be expanded and contracted, 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 catheter of claim 10 , wherein the fourth marker is located in the central region.

12. The catheter according to claim 10, wherein the ratio of the length of the minor axis to the length of the major axis in the outline of the fourth marker in a cross section perpendicular to the longitudinal direction (length of minor axis / length of major axis) is 0.6 or more and less than 1.

0.

13. The catheter described in claim 10, wherein the length of the major axis of the fourth marker in a cross section perpendicular to the longitudinal direction is 50% or more and 150% or less of the average length of the major axis of the first marker, the second marker, and the third marker in a cross section perpendicular to the longitudinal direction.

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