Catheter

Abstract

A catheter (100) has: a first shaft (1) provided with a first cylindrical part (10), a bag-like body part (20), and a flow passage (40); and a second shaft (2) provided with a second cylindrical part (50) and an expanded diameter part (60). A first portion (61) is located in the lumen of the first shaft (1), and a second portion (62) is located outside the first shaft (1). The maximum outer diameter of the second portion (62) is greater than the maximum outer diameter of the first cylindrical part (10), and the outer surface of the first portion (61) is in contact with the inside of the first shaft (1).

Description

catheter

[0001] The present invention relates to a catheter.

[0002] For example, a resin tube is used to transport a medical device such as a balloon or a stent to a treatment site. Specifically, the medical device is placed in the lumen of the resin tube and inserted into a body cavity such as a blood vessel, and then transported to the treatment site. If the resin tube used in this case has a simple cylindrical shape as described in Patent Document 1, there is a problem that the tip of the resin tube hits the wall of the body cavity, causing damage to the wall or reducing passability.

[0003] Patent Document 2 describes a catheter that can reduce damage to the walls of a body cavity. The catheter has a long, elastic tubular component with at least one lumen. A soft, deformable tip component is attached to the distal end of the catheter, and the tip component expands in outer diameter and increases in contact area when pressed against a relatively stationary surface. Patent Document 2 describes that this makes it possible to reduce the pressure or force per unit area applied to the tissue.

[0004] Patent Document 3 describes a medical technical instrument that is easy to operate. The instrument includes a longitudinally elongated, flexible inner body, a longitudinally elongated outer envelope surrounding the inner body at least partially on the circumferential side, and a device for transitioning the instrument from a flexible state to a rigid state and vice versa. The inner body is formed in a double-tube shape, with an inner tube forming an inner wall and an outer tube forming an outer wall and concentrically surrounding the inner tube. The device for transitioning the instrument from a flexible state to a rigid state and vice versa is described as being easy to operate by increasing the pressure in the annular gap to radially expand the outer tube, thereby applying pressure to the envelope and causing the instrument to become rigid. Patent Document 3 also describes that while the outer diameter of the double-tube inner body increases, the size of the internal space of the inner body remains fixed.

[0005] Furthermore, when performing treatment on a blood vessel or the like, an expandable / contractable portion such as a balloon or stent may be delivered to the treatment site, which is the target of treatment, and the diameter of the expandable / contractable portion may be expanded. Because the size of the treatment site varies from patient to patient, there has been a need for a catheter that allows the length of the balloon or stent that contacts the treatment site to be adjusted to the desired length.

[0006] Patent document 4 describes a technology that allows the length of the portion of the balloon that abuts the treatment site to be adjusted by expanding the diameter of the balloon while part of the balloon is positioned inside the sheath.

[0007] U.S. Patent No. 9,327,101 JP-A-60-040069 JP-A-2009-505700 U.S. Patent No. 6,884,257

[0008] The first problem corresponding to the first invention is as follows.

[0009] The catheter described in Patent Document 2 prevents damage to the wall of the body cavity by expanding the outer diameter of the tip part, but the configuration of the catheter described in Patent Document 2 does not solve the problem that the expanded tip part is prone to getting caught on the wall of the body cavity, making it difficult to pass through the body cavity.

[0010] Furthermore, the medical technology instrument described in Patent Document 3 improves operability by applying pressure to expand the outer diameter, thereby creating a rigid state, and the expanded diameter portion is prone to getting caught on the wall of the body cavity, so there is still room for improvement in terms of improving passability within the body cavity.

[0011] In both the catheter of Patent Document 2 and the medical technical instrument of Patent Document 3, it is necessary to transport and place a medical device such as a balloon or a stent to a treatment site, which is a treatment target. For this reason, the lumen into which the medical device is inserted needs to have an inner diameter large enough to allow the medical device to pass from the distal end to the proximal end.

[0012] The first invention was made in consideration of the first problem, and its purpose is to provide a catheter that can easily prevent damage to the wall of a body cavity when transporting it to a treatment site and can also easily improve its passability within the body cavity.

[0013] The second problem corresponding to the second invention is as follows.

[0014] The catheter described in Patent Document 4 has a problem in that it is difficult to visually confirm the position of the proximal end of the balloon, which is in contact with the treatment site.

[0015] The second invention was made in consideration of the second problem, and its purpose is to provide a catheter that makes it easy to adjust the length of the expandable / contractable portion that abuts against the treatment portion to the desired length and makes it easy to visualize the proximal end of the expandable / contractable portion that abuts against the treatment portion.

[0016] A first embodiment of the first invention that can solve the first problem is as follows: [1] A catheter comprising: a first shaft having a longitudinal direction and a lumen extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction, a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape, and a flow path having a space through which a fluid can be injected up to the bag-shaped body portion; and a second shaft comprising: a second tubular portion and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion, wherein a first portion that is a part of the expanding / contracting diameter portion is located in the lumen of the first shaft, a second portion that is a portion of the expanding / contracting diameter portion located distal to the first portion is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, and the outer surface of the first portion is inscribed in the first shaft, A catheter in which, when the expandable / contractable portion is not positioned in the lumen of the distal end of the bag-shaped body portion and the bag-shaped body portion is pressurized by injecting fluid into the flow path, the minimum inner diameter of the bag-shaped body portion is larger than the minimum inner diameter of the bag-shaped body portion when it is not pressurized by injecting fluid into the flow path.

[0017] The catheter can be used, for example, by inserting the distal end of the first shaft to a treatment site, and then protruding a portion of the expandable / contractable section disposed in the lumen of the first shaft from the first shaft. When transporting the first shaft to the treatment site, the first shaft is placed in a state where it is not pressurized by injecting a fluid into the flow path. In this state, the minimum inner diameter of the pouch-like body portion is smaller than the minimum inner diameter of the pouch-like body portion when it is pressurized by injecting a fluid into the flow path, making it easier to reduce the outer diameter of the pouch-like body portion. This makes it less likely for the first shaft to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve its passability through the body cavity. After transporting the first shaft to the treatment site, the pouch-like body portion is placed in a state where it is pressurized by injecting a fluid into the flow path. In this state, the minimum inner diameter of the pouch-like body portion is larger than the minimum inner diameter of the pouch-like body portion when it is not pressurized by injecting a fluid into the flow path. This makes it easier to protrude a portion of the expandable / contractable section from the expanded pouch-like body portion. After the bag-shaped body portion is pressurized by injecting a fluid into the flow path, the first portion is positioned in the lumen of the first shaft, the second portion is positioned outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, and the outer surface of the first portion is inscribed in the first shaft. This makes it easy to adjust the length of the expandable diameter portion that abuts on the treatment portion to a desired length.

[0018] The catheter described in [1] above is preferably any one of [2] to [8] below. [2] The catheter described in [1], wherein, when the diameter-expanding section is not disposed in the lumen of the distal end of the bag-shaped body section and the bag-shaped body section is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path, the minimum inner diameter of the bag-shaped body section is larger than the minimum inner diameter of the bag-shaped body section when no pressurization is performed by injecting a fluid into the flow path. [3] The catheter described in [1] or [2], wherein, when no pressurization is performed by injecting a fluid into the flow path, the first tubular section has a protrusion that protrudes radially inward of the first tubular section. [4] The catheter described in any one of [1] to [3], wherein a radiopaque section is provided at the distal end of the bag-shaped body section. [5] The catheter described in any one of [1] to [4], wherein the fluid is radiopaque. [6] The catheter described in any one of [1] to [5], wherein a reinforcing member is disposed between the flow path and the lumen of the first tubular section. [7] The catheter according to [6], wherein the reinforcing member is made of metal, and the reinforcing member is made of a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof. [8] The catheter according to any one of [1] to [7], wherein, in a state in which the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the maximum inner diameter of the bag-shaped body portion is larger than the maximum inner diameter of the first tubular portion.

[0019] The second embodiment of the first invention that can solve the first problem is as follows. [9] A catheter comprising: a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction; a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape; a bulging portion bulging radially inward of the first tubular portion; and a flow path having a space in which a fluid can be injected up to the bag-shaped body portion and a space in which a fluid can be injected up to the bulging portion; and a second shaft comprising: a second tubular portion and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion; wherein a first portion that is a part of the expanding / contracting diameter portion is located in the inner cavity of the first shaft, a second portion that is a portion of the expanding / contracting diameter portion located distal to the first portion is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer surface of the first portion is inscribed in the first shaft, and the bulging portion bulges and bulges radially inward of the first tubular portion, the bulging portion bulges radially inward of the first tubular portion when the bulging portion is pressurized by injecting fluid into the flow path, and when the expandable / contractable portion is not positioned in the lumen of the distal end of the bag-shaped body portion, the minimum inner diameter of the bag-shaped body portion when the bag-shaped body portion is pressurized by injecting fluid into the flow path is larger than the minimum inner diameter of the bag-shaped body portion when it is not pressurized by injecting fluid into the flow path.

[0020] The catheter can be used, for example, by inserting the distal end of the first shaft to a treatment site, and then protruding a portion of the expandable / contractable section disposed in the lumen of the first shaft from the first shaft. When transporting the first shaft to the treatment site, the first shaft is in a state where no pressurization is being performed by injecting a fluid into the flow path. In this state, the minimum inner diameter of the bag-like body portion is smaller than the minimum inner diameter of the bag-like body portion when the bag-like body portion is pressurized by injecting a fluid into the flow path, making it easier to reduce the outer diameter of the bag-like body portion. This makes it less likely for the first shaft to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. After transporting the first shaft to the treatment site, the bag-like body portion is in a state where it is pressurized by injecting a fluid into the flow path. In this state, the minimum inner diameter of the bag-like body portion is larger than the minimum inner diameter of the bag-like body portion when the bag-like body portion is not pressurized by injecting a fluid into the flow path. This makes it easier to protrude a portion of the expandable / contractable diameter section disposed in the lumen of the first shaft from the expanded-diameter bag-shaped body section. After the bag-shaped body section is pressurized by injecting fluid into the flow path, the first portion is positioned in the lumen of the first shaft, the second portion is positioned outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular section, the outer surface of the first portion is inscribed in the first shaft, and the bulging portion bulges radially inward of the first tubular section. This makes it easier to adjust the length of the expandable / contractable diameter section that abuts against the treatment section to a desired length. Furthermore, the bulging portion bulges radially inward of the first tubular section, making it easier to abut against the second shaft. This makes it easier to suppress movement of the second shaft in the longitudinal direction of the first shaft.

[0021] The catheter described in [9] above is preferably any one of

[10] to

[23] below.

[10] The catheter described in [9], wherein the bulging portion bulges radially inward of the first tubular portion when pressurized to a first predetermined pressure or higher by injection of fluid into the flow path, and the minimum inner diameter of the bag-shaped body portion when pressurized to a second predetermined pressure or higher by injection of fluid into the flow path with the expandable / contractable portion not disposed in the lumen of the distal end of the bag-shaped body portion is larger than the minimum inner diameter of the bag-shaped body portion when not pressurized by injection of fluid into the flow path.

[11] The catheter described in

[10] , wherein the second predetermined pressure is smaller than the first predetermined pressure.

[12] The catheter described in any one of [9] to

[11] , wherein the fluid injected up to the bag-shaped body portion passes through a space through which fluid can be injected up to the bulging portion.

[13] The catheter according to

[10] or

[11] , wherein when the flow path is pressurized to the first predetermined pressure or higher by injection of a fluid, a surface of the bulging portion located on the radially inner side of the first tubular portion abuts the expanding / contracting diameter portion.

[14] The catheter according to

[10] or

[11] , wherein when the flow path is pressurized to the first predetermined pressure or higher by injection of a fluid, the lumen of the first tubular portion is blocked by the expanded bulging portion or the expanding / contracting diameter portion.

[15] The catheter according to

[10] or

[11] , wherein when the flow path is pressurized to the first predetermined pressure or higher by injection of a fluid, in a state in which the second shaft is not positioned distal to the proximal end of the bulging portion, a first surface portion that is a part of the surface of the bulging portion located on the radially inner side of the first tubular portion abuts a second surface portion that is a part of the surface of the bulging portion located on the radially inner side of the first tubular portion and is different from the first surface portion.

[16] A catheter as described in

[10] or

[11] , wherein when the second shaft is not positioned distal to the proximal end of the bulge portion and the flow path is pressurized to a pressure equal to or greater than the first predetermined pressure by injecting a fluid into the flow path, the inner cavity of the first tubular portion is blocked by the bulged bulge portion.

[17] The catheter according to any one of [9] to

[16] , wherein the frictional force of the surface of the bulging portion located on the radially inner side of the first tubular portion is higher than the frictional force of the inner surface of the first tubular portion facing the lumen of the first tubular portion.

[18] The catheter according to any one of [9] to

[17] , wherein the bulging portion is located proximal to the proximal end of the sac-shaped body portion.

[19] The catheter according to any one of [9] to

[18] , wherein a radiopaque portion is provided at the distal end of the sac-shaped body portion.

[20] The catheter according to any one of [9] to

[19] , wherein the fluid is radiopaque.

[21] The catheter according to any one of [9] to

[20] , wherein a reinforcing member is disposed between the flow path and the lumen of the first tubular portion.

[22] The catheter according to

[21] , wherein the reinforcing member is made of metal, and wherein the reinforcing member is formed of a tube, a braid with woven wire, a coil with wound wire, or a combination thereof.

[23] A catheter described in any one of [9] to

[22] , wherein when the maximum outer diameter of the second part of the expandable diameter section is larger than the maximum outer diameter of the first tubular section, the maximum inner diameter of the bag-shaped body section is larger than the maximum inner diameter of the first tubular section.

[0022] A third embodiment of the first invention that can solve the first problem is as follows:

[24] A first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction, a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape, a bulging portion bulging outward in the radial direction of the first tubular portion, and a flow path having a space in which a fluid can be injected up to the bag-shaped body portion and a space in which a fluid can be injected up to the bulging portion; and a second shaft that comprises a second tubular portion and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion, and is disposed in the inner cavity of the first shaft. a catheter in which a first portion, which is a part of the expandable / contractable diameter section, is located in the lumen of the first shaft, a second portion, which is a portion of the expandable / contractable diameter section located distal to the first portion, is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer surface of the first portion is inscribed in the first shaft, and the bulging portion bulges and bulges radially outward of the first tubular portion, wherein the bulging portion bulges and bulges radially outward of the first tubular portion when the bulging portion is pressurized by injecting a fluid into the flow path, and when the expandable / contractable diameter section is not positioned in the lumen of the distal end of the bag-shaped body portion, the minimum inner diameter of the bag-shaped body portion when the bag-shaped body portion is pressurized by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-shaped body portion when it is not pressurized by injecting a fluid into the flow path.

[0023] The catheter can be used, for example, by inserting the distal end of the first shaft to a treatment site, and then protruding a portion of the expandable / contractable section disposed in the lumen of the first shaft from the first shaft. When transporting the first shaft to the treatment site, the first shaft is in a state where no pressurization is being performed by injecting a fluid into the flow path. In this state, the minimum inner diameter of the bag-like body portion is smaller than the minimum inner diameter of the bag-like body portion when the bag-like body portion is pressurized by injecting a fluid into the flow path, making it easier to reduce the outer diameter of the bag-like body portion. This makes it less likely for the first shaft to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. After transporting the first shaft to the treatment site, the bag-like body portion is in a state where it is pressurized by injecting a fluid into the flow path. In this state, the minimum inner diameter of the bag-like body portion is larger than the minimum inner diameter of the bag-like body portion when the bag-like body portion is not pressurized by injecting a fluid into the flow path. This makes it easier to protrude a portion of the expandable / contractable diameter section disposed in the lumen of the first shaft from the expanded-diameter bag-shaped body section. After the bag-shaped body section is pressurized by injecting fluid into the flow path, the first portion is positioned in the lumen of the first shaft, the second portion is positioned outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular section, the outer surface of the first portion is inscribed within the first shaft, and the bulging portion bulges outward in the radial direction of the first tubular section. This makes it easier to adjust the length of the expandable / contractable diameter section that contacts the treatment section to a desired length. Furthermore, because the bulging portion bulges outward in the radial direction of the first tubular section, the bulging portion can be easily brought into contact with the wall of the body cavity. This makes it easier to suppress movement of the first shaft within the body cavity.

[0024] The catheter described in

[24] above is preferably any one of

[25] to

[36] below.

[25] The catheter described in

[24] , wherein the bulging portion bulges outward in the radial direction of the first tubular portion when pressurized to a third predetermined pressure or higher by injection of fluid into the flow path, and the minimum inner diameter of the bag-shaped body portion when pressurized to a fourth predetermined pressure or higher by injection of fluid into the flow path with the expandable / contractable portion not disposed in the lumen of the distal end of the bag-shaped body portion is larger than the minimum inner diameter of the bag-shaped body portion when not pressurized by injection of fluid into the flow path.

[26] The catheter described in

[25] , wherein the fourth predetermined pressure is equal to or higher than the third predetermined pressure.

[27] The catheter described in any one of

[24] to

[26] , wherein the bulging height of the bulging portion in the radial direction of the first tubular portion varies in the circumferential direction of the first tubular portion.

[28] The catheter according to any one of

[24] to

[27] , wherein the fluid injected up to the sac-shaped body portion passes through a space through which the fluid can be injected up to the bulging portion.

[29] The catheter according to any one of

[24] to

[28] , wherein the frictional force of the outer surface of the bulging portion is higher than the frictional force of the outer surface of the first tubular portion.

[30] The catheter according to any one of

[24] to

[29] , wherein the first tubular portion has a protruding portion that protrudes radially inward of the first tubular portion when no pressurization is performed by injecting a fluid into the flow path.

[31] The catheter according to any one of

[24] to

[30] , wherein the bulging portion is located proximal to the proximal end of the sac-shaped body portion.

[32] The catheter according to any one of

[24] to

[31] , wherein a radiopaque portion is provided at the distal end of the sac-shaped body portion.

[33] The catheter according to any one of

[24] to

[32] , wherein the fluid is radiopaque.

[34] The catheter according to any one of

[24] to

[33] , wherein a reinforcing member is disposed between the flow path and the lumen of the first tubular portion.

[35] The catheter according to

[34] , wherein the reinforcing member is made of metal, and the reinforcing member is made of a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof.

[36] A catheter according to any one of

[24] to

[35] , wherein when the maximum outer diameter of the second part of the expandable / contractable diameter section is larger than the maximum outer diameter of the first tubular section, the maximum inner diameter of the bag-shaped body section is larger than the maximum inner diameter of the first tubular section.

[0025] The fourth embodiment of the first invention that can solve the first problem is as follows.

[37] A catheter comprising: a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction; a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape, the bag-shaped body portion having an X-ray opaque portion at its distal end; and a flow path having a space into which a fluid can be injected up to the bag-shaped body portion; and a second shaft comprising: a second tubular portion and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion; wherein a first portion that is a part of the expanding / contracting diameter portion is located in the inner cavity of the first shaft, a second portion that is a portion of the expanding / contracting diameter portion located distal to the first portion is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the first portion is inscribed in the first shaft, and the outer diameter at the distal end of the bag-shaped body portion is larger than the maximum outer diameter of the first tubular portion, A catheter in which, when the expandable / contractable portion is not positioned in the lumen of the distal end of the bag-shaped body portion and the bag-shaped body portion is pressurized by injecting fluid into the flow path, the minimum inner diameter of the bag-shaped body portion is larger than the minimum inner diameter of the bag-shaped body portion when it is not pressurized by injecting fluid into the flow path.

[0026] The catheter can be used, for example, by inserting the distal end of the first shaft to a treatment site, and then protruding a portion of the expandable / contractable section disposed in the lumen of the first shaft from the first shaft. When transporting the first shaft to the treatment site, the first shaft is placed in a state where it is not pressurized by injecting a fluid into the flow path. In this state, the minimum inner diameter of the pouch-like body portion is smaller than the minimum inner diameter of the pouch-like body portion when it is pressurized by injecting a fluid into the flow path, making it easier to reduce the outer diameter of the pouch-like body portion. This makes it less likely for the first shaft to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve its passability through the body cavity. After transporting the first shaft to the treatment site, the pouch-like body portion is placed in a state where it is pressurized by injecting a fluid into the flow path. In this state, the minimum inner diameter of the pouch-like body portion is larger than the minimum inner diameter of the pouch-like body portion when it is not pressurized by injecting a fluid into the flow path. This makes it easier to protrude a portion of the expandable / contractable section from the expanded pouch-like body portion. After the bag-shaped body portion is pressurized by injecting a fluid into the flow path, the first portion is positioned within the lumen of the first shaft, the second portion is positioned outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, and the first portion is inscribed within the first shaft. This makes it easy to adjust the length of the expandable / contractable portion that contacts the treatment portion to a desired length. Furthermore, because the outer diameter at the distal end of the bag-shaped body portion is larger than the maximum outer diameter of the first tubular portion and the distal end of the bag-shaped body portion is provided with an X-ray opaque portion, the proximal end of the expandable / contractable portion that contacts the treatment portion can be easily visualized.

[0027] The catheter described in

[37] above is preferably any one of

[38] to

[43] below.

[38] The catheter described in

[37] , wherein, when the diameter-expanding section is not disposed in the lumen of the distal end of the bag-shaped body section and the bag-shaped body section is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path, the minimum inner diameter of the bag-shaped body section is larger than the minimum inner diameter of the bag-shaped body section when no pressurization is performed by injecting a fluid into the flow path.

[39] The catheter described in

[37] or

[38] , wherein, when no pressurization is performed by injecting a fluid into the flow path, the first tubular section has a protrusion that protrudes radially inward of the first tubular section.

[40] The catheter described in any one of

[37] to

[39] , wherein a reinforcing member is disposed between the flow path and the lumen of the first tubular section.

[41] The catheter described in

[40] , wherein the reinforcing member is made of metal and is composed of a tube, a braid with woven wire, a coil with wound wire, or a combination thereof.

[42] The catheter according to any one of

[37] to

[41] , wherein, when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the maximum inner diameter of the sac-shaped body portion is larger than the maximum inner diameter of the first tubular portion.

[43] The catheter according to any one of

[37] to

[42] , when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer diameter at the distal end of the sac-shaped body portion is within ±3 mm of the maximum outer diameter of the second portion.

[0028] The second embodiment of the invention that can solve the second problem is as follows.

[44] A catheter comprising: a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction; a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape; and a flow path having a space through which a fluid having radiopacity can be injected up to the bag-shaped body portion; and a second shaft disposed in the inner cavity of the first shaft, the second tubular portion comprising: a second tubular portion; and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion, wherein a first portion that is a part of the expanding / contracting diameter portion is located in the inner cavity of the first shaft, a second portion that is a portion of the expanding / contracting diameter portion located distal to the first portion is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the first portion is inscribed within the first shaft, and the outer diameter at the distal end of the bag-shaped body portion is larger than the maximum outer diameter of the first tubular portion.

[0029] The catheter can be used, for example, by inserting the distal end of the first shaft to a treatment site and then protruding a portion of the expandable / contractable section disposed within the lumen of the first shaft from the first shaft. After the expandable / contractable section protrudes from the lumen of the first shaft, the first portion is positioned within the lumen of the first shaft, the second portion is positioned outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular section, and the first portion is inscribed within the first shaft. This makes it easier to adjust the length of the expandable / contractable section that contacts the treatment site to a desired length. Furthermore, because the outer diameter at the distal end of the sac-shaped body section is larger than the maximum outer diameter of the first tubular section, and because the distal end of the sac-shaped body section can be easily visualized by injecting a radiopaque fluid, the proximal end of the expandable / contractable section that contacts the treatment site can be easily visualized.

[0030] The catheter described in

[44] above is preferably any one of

[45] to

[51] below.

[45] The catheter described in

[44] , wherein the first tubular portion has a protrusion that protrudes radially inward of the first tubular portion when no pressurization is performed by injecting a fluid into the flow path.

[46] The catheter described in

[44] or

[45] , wherein a reinforcing member is disposed between the flow path and the lumen of the first tubular portion.

[47] The catheter described in

[46] , wherein the reinforcing member is made of metal, and the reinforcing member is formed of a tube, a braid in which a wire is woven, a coil in which a wire is wound, or a combination thereof.

[48] The catheter described in any one of

[44] to

[47] , wherein the maximum inner diameter of the bag-shaped body portion is larger than the maximum inner diameter of the first tubular portion when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion.

[49] The catheter according to any one of

[44] to

[48] , wherein, when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer diameter at the distal end of the bag-shaped body portion is within ±3 mm of the maximum outer diameter of the second portion.

[50] The catheter according to any one of

[44] to

[49] , wherein, when the expandable / contractible section is not disposed in the lumen of the distal end of the bag-shaped body portion, the minimum inner diameter of the bag-shaped body portion when pressurized by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-shaped body portion when not pressurized by injecting a fluid into the flow path.

[51] The catheter according to

[50] , wherein, when the expandable / contractible section is not disposed in the lumen of the distal end of the bag-shaped body portion, the minimum inner diameter of the bag-shaped body portion when pressurized at a predetermined pressure or higher by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-shaped body portion when not pressurized by injecting a fluid into the flow path.

[0031] The catheter according to the first embodiment of the invention is less likely to get caught on the wall of the body cavity when the first shaft is delivered to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity. The catheter according to the first embodiment of the invention also makes it easier to make a portion of the expandable / contractable section protrude from the expanded-diameter bag-shaped body. Furthermore, the catheter according to the first embodiment of the invention makes it easier to adjust the length of the expandable / contractable section that contacts the treatment site to a desired length.

[0032] The catheter according to the second embodiment of the present invention makes it easy to adjust the length of the expandable / contractable portion that contacts the treatment portion to the desired length, and makes it easy to visualize the proximal end of the expandable / contractable portion that contacts the treatment portion.

[0033] FIG. 1 is an enlarged cross-sectional view (partial side view) of a distal portion of a catheter according to an embodiment of the present invention, illustrating a state in which pressurization by injection of a fluid into the flow channel is not being performed. FIG. 2 is a cross-sectional view of the catheter shown in FIG. 1 taken along line II-II. FIG. 3 is a cross-sectional view (partial side view) of the catheter shown in FIG. 1 when pressurized by injection of a fluid into the flow channel. FIG. 4 is a cross-sectional view (partial side view) of the catheter shown in FIG. 1 when pressurized by injection of a fluid into the flow channel. FIG. 5 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 5. FIG. 7 is a cross-sectional view of the first shaft shown in FIG. 6 taken along line VII-VII. FIG. 8 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 6 when pressurization by injection of a fluid into the flow channel is not being performed. FIG. 9 is a cross-sectional view of the first shaft shown in FIG. 8 when pressurized by injection of a fluid into the flow channel. FIG. 10 is a cross-sectional view of the first shaft shown in FIG. 8 taken along line X-X. FIG. 11 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 8. FIG. 12 is a cross-sectional view of the first shaft shown in FIG. 11 taken along line XII-XII. FIG. 13 is a cross-sectional view of a modified example of the first shaft shown in FIG. 8. FIG. 14 is a cross-sectional view of the first shaft shown in FIG. 13 taken along line XIV-XIV. FIG. 15 is a cross-sectional view of a modified example of the first shaft shown in FIG. 8. FIG. 16 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in FIG. 4. FIG. 17 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in FIG. 4. FIG. 18 is an enlarged cross-sectional view (partially a side view) of a distal portion of a catheter according to an embodiment of the present invention, showing a state in which pressurization by injection of a fluid into the flow path is not being performed. FIG. 19 is a cross-sectional view of the catheter shown in FIG. 18 taken along line XIX-XIX. Figure 20 shows a cross-sectional view (partially a side view) of the catheter shown in Figure 18 when it is pressurized by injecting a fluid into the flow path. Figure 21 shows a cross-sectional view (partially a side view) of the catheter shown in Figure 18 when it is pressurized by injecting a fluid into the flow path.FIG. 22 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 23 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 22. FIG. 24 is a cross-sectional view of the first shaft shown in FIG. 23 taken along line XXIV-XXIV. FIG. 25 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 23, showing a state in which pressurization due to fluid injection into the flow channel has not been performed. FIG. 26 is a cross-sectional view of the first shaft shown in FIG. 25 when pressurized due to fluid injection into the flow channel. FIG. 27 is a cross-sectional view of the first shaft shown in FIG. 25 when pressurized due to fluid injection into the flow channel. FIG. 28 is a cross-sectional view of the first shaft shown in FIG. 27 taken along line XXVIII-XXVIII. FIG. 29 is a cross-sectional view showing a modified version of the first shaft shown in FIG. 28. FIG. 30 is a cross-sectional view showing a modified version of the first shaft shown in FIG. 28. FIG. 31 is a cross-sectional view of the first shaft shown in FIG. 25 taken along line XXXI-XXXI. FIG. 32 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 25. FIG. 33 is a cross-sectional view of the first shaft shown in FIG. 32 taken along line XXXIII-XXXIII. FIG. 34 is a cross-sectional view of a modified example of the first shaft shown in FIG. 25. FIG. 35 is a cross-sectional view of the first shaft shown in FIG. 34 taken along line XXXV-XXXV. FIG. 36 is a cross-sectional view of a modified example of the first shaft shown in FIG. 25. FIG. 37 is an enlarged cross-sectional view (partially a side view) of a distal portion of a catheter according to an embodiment of the present invention, showing a state in which pressurization by injection of fluid into the flow path has not been performed. FIG. 38 is a cross-sectional view of the catheter shown in FIG. 37 taken along line XXXVIII-XXXVIII. FIG. 39 is a cross-sectional view (partially a side view) of the catheter shown in FIG. 37 when pressurized by injection of fluid into the flow path. Fig. 40 is a cross-sectional view (partial side view) of the catheter shown in Fig. 37 when pressurized by injection of fluid into the flow path. Fig. 41 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. Fig. 42 is an enlarged cross-sectional view of a portion of the first shaft shown in Fig. 41 that is located distally.FIG. 43 is a cross-sectional view of the first shaft shown in FIG. 42 taken along line XLIII-XLIII. FIG. 44 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 42, showing a state in which pressurization by injection of fluid into the flow channel is not being performed. FIG. 45 is a cross-sectional view of the first shaft shown in FIG. 44 when pressurized by injection of fluid into the flow channel. FIG. 46 is a cross-sectional view of the first shaft shown in FIG. 44 when pressurized by injection of fluid into the flow channel. FIG. 47 is a cross-sectional view of the first shaft shown in FIG. 46 taken along line XLVII-XLVII. FIG. 48 is a cross-sectional view showing a modified version of the first shaft shown in FIG. 47. FIG. 49 is a cross-sectional view showing a modified version of the first shaft shown in FIG. 47. FIG. 50 is a cross-sectional view of the first shaft shown in FIG. 44 taken along line L-L. FIG. 51 is a cross-sectional view showing a modified version of the first shaft shown in FIG. 44. FIG. 52 is a cross-sectional view of the first shaft shown in FIG. 51 taken along line LII-LII. FIG. 53 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 44. FIG. 54 is a cross-sectional view of the first shaft shown in FIG. 53 taken along line LIV-LIV. FIG. 55 is a cross-sectional view of a modified example of the first shaft shown in FIG. 44. FIG. 56 is an enlarged cross-sectional view (partially a side view) of a distal portion of a catheter according to an embodiment of the present invention, showing a state in which pressurization due to injection of fluid into the flow channel is not performed. FIG. 57 is a cross-sectional view of the catheter shown in FIG. 56 taken along line LVII-LVII. FIG. 58 is a cross-sectional view (partially a side view) of the catheter shown in FIG. 56 when pressurized due to injection of fluid into the flow channel. FIG. 59 is a cross-sectional view (partially a side view) of the catheter shown in FIG. 56 when pressurized due to injection of fluid into the flow channel. FIG. 60 is a side view showing an example of a first shaft provided in a catheter according to an embodiment of the present invention. Fig. 61 is an enlarged cross-sectional view of a portion of the first shaft shown in Fig. 60 that is located on the distal side. Fig. 62 is a cross-sectional view of the first shaft shown in Fig. 61 taken along line LXII-LXII. Fig. 63 is an enlarged cross-sectional view of a portion of the first shaft shown in Fig. 61 that is located on the distal side, illustrating a state in which pressurization by injection of a fluid into the flow channel has not been performed.Fig. 64 is a cross-sectional view of the first shaft shown in Fig. 63 when it is pressurized by injection of fluid into the flow channel. Fig. 65 is a cross-sectional view of the first shaft shown in Fig. 63 taken along line LXV-LXV. Fig. 66 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 63. Fig. 67 is a cross-sectional view of the first shaft shown in Fig. 66 taken along line LXVII-LXVII. Fig. 68 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 63. Fig. 69 is a cross-sectional view of the first shaft shown in Fig. 68 taken along line LXIX-LXIX. Fig. 70 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 63. Fig. 71 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Fig. 59. Fig. 72 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Fig. 59. FIG. 73 is an enlarged cross-sectional view (partial side view) of a distal portion of a catheter according to an embodiment of the present invention, illustrating a state in which pressurization by injection of fluid into the flow path is not being performed. FIG. 74 is a cross-sectional view of the catheter shown in FIG. 73 taken along line LXXIV-LXXIV. FIG. 75 is a cross-sectional view (partial side view) of the catheter shown in FIG. 73 when pressurized by injection of fluid into the flow path. FIG. 76 is a cross-sectional view (partial side view) of the catheter shown in FIG. 73 when pressurized by injection of fluid into the flow path. FIG. 77 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 78 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 77. FIG. 79 is a cross-sectional view of the first shaft shown in FIG. 78 taken along line LXXIX-LXXIX. FIG. 80 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 78 when pressurization by injection of fluid into the flow path is not being performed. Fig. 81 is a cross-sectional view of the first shaft shown in Fig. 80 when it is pressurized by injecting a fluid into the flow path. Fig. 82 is a cross-sectional view of the first shaft shown in Fig. 80 taken along line LXXXII-LXXXII. Fig. 83 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 80. Fig. 84 is a cross-sectional view of the first shaft shown in Fig. 83 taken along line LXXXIV-LXXXIV. Fig. 85 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 80.Figure 86 is a cross-sectional view taken along line LXXXVI-LXXXVI of the first shaft shown in Figure 85. Figure 87 is a cross-sectional view showing a modified example of the first shaft shown in Figure 80. Figure 88 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Figure 76. Figure 89 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Figure 76.

[0034] The present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the illustrated examples, and appropriate modifications can be made within the scope of the above and below-described purpose, and all such modifications are within the technical scope of the present invention. In each drawing, hatching, symbols, etc. may be omitted for convenience. In such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various parts in the drawings may differ from their actual dimensions, as priority is given to helping understand the features of the present invention.

[0035] (First Invention) First, the first invention will be described. The first invention includes a first embodiment, a second embodiment, a third embodiment, and a fourth embodiment.

[0036] (First embodiment) Hereinafter, the first embodiment of the first invention will be described.

[0037] A first embodiment of the first invention is a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft including: a first tubular portion extending in the longitudinal direction of the first shaft; a bag-like body portion located distal to the first tubular portion and formed in an annular shape; and a flow path having a space through which a fluid can be injected up to the bag-like body portion; and a second shaft including a second tubular portion and an expandable / contractable portion fixed to a distal portion of the second tubular portion, wherein a first portion which is a part of the expandable / contractable portion is located in the inner cavity of the first shaft and the expandable / contractable portion is fixed to a distal portion of the second tubular portion. The catheter has a second portion, which is located distal to the first portion, located outside the first shaft, a maximum outer diameter of the second portion greater than the maximum outer diameter of the first tubular portion, and an outer surface of the first portion inscribed within the first shaft, and is characterized in that when the expandable diameter portion is not positioned in the lumen of the distal end of the bag-like body portion, the minimum inner diameter of the bag-like body portion when it is pressurized by injecting fluid into the flow path is greater than the minimum inner diameter of the bag-like body portion when it is not pressurized by injecting fluid into the flow path.

[0038] The overall configuration of the first embodiment will be described with reference to Figures 1 to 17. The figures show a catheter 100 having a first shaft 1 equipped with a first tubular portion 10, a bag-shaped portion 20, and a flow path 40, and a second shaft 2 disposed in the lumen of the first shaft 1. In the figures, the longitudinal direction of the first tubular portion 10 is indicated by x, and the radial direction is indicated by y.

[0039] In this specification, the proximal side refers to the direction toward the user's hand relative to the longitudinal direction x of the first tubular portion 10, and the distal side refers to the opposite side of the proximal side, i.e., the direction toward the treatment target. Furthermore, when each component or part is divided into two equal parts in the longitudinal direction x of the first tubular portion 10, the distal portion of each component or part is referred to as the distal portion of each component or part, and the proximal portion of each component or part is referred to as the proximal portion of each component or part. The distal end of each component or part is the most distal end of each component or part. The proximal end of each component or part is the most proximal end of each component or part. The end includes the peripheral portion of the end. In other words, the distal end refers to the distal end and the peripheral portion of the distal end, and the proximal end refers to the proximal end and the peripheral portion of the proximal end. This also applies to the second embodiment, third embodiment, fourth embodiment, and second invention.

[0040] FIG. 1 is an enlarged cross-sectional view (partial side view) of a distal portion of a catheter according to an embodiment of the present invention, illustrating a state in which pressurization by injection of a fluid into the flow channel is not being performed. FIG. 2 is a cross-sectional view of the catheter shown in FIG. 1 taken along line II-II. FIG. 3 is a cross-sectional view (partial side view) of the catheter shown in FIG. 1 when pressurized by injection of a fluid into the flow channel. FIG. 4 is a cross-sectional view (partial side view) of the catheter shown in FIG. 1 when pressurized by injection of a fluid into the flow channel. FIG. 5 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 5. FIG. 7 is a cross-sectional view of the first shaft shown in FIG. 6 taken along line VII-VII. FIG. 8 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 6 when pressurization by injection of a fluid into the flow channel is not being performed. FIG. 9 is a cross-sectional view of the first shaft shown in FIG. 8 when pressurized by injection of a fluid into the flow channel. Fig. 10 is a cross-sectional view taken along line X-X of the first shaft shown in Fig. 8. Fig. 11 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 8. Fig. 12 is a cross-sectional view taken along line XII-XII of the first shaft shown in Fig. 11. Fig. 13 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 8. Fig. 14 is a cross-sectional view taken along line XIV-XIV of the first shaft shown in Fig. 13. Fig. 15 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 8. Fig. 16 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Fig. 4. Fig. 17 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Fig. 4.

[0041] As shown in FIGS. 1 to 4, the catheter 100 has a first shaft 1 and a second shaft 2 .

[0042] The first shaft 1 includes a first cylindrical portion 10 , a bag-shaped portion 20 , and a flow path 40 .

[0043] As shown in FIGS. 1 to 4, the first shaft 1 has a longitudinal direction and an inner lumen extending in the longitudinal direction.

[0044] 1 to 4, the first shaft 1 has a first tubular portion 10 extending in the longitudinal direction of the first shaft 1. The first tubular portion 10 has a longitudinal direction x and a radial direction y that is a direction perpendicular to the longitudinal direction x. The first tubular portion 10 preferably has an inner cavity 11 extending in the longitudinal direction x of the first tubular portion 10.

[0045] As shown in Figures 1, 3, and 4, the bag-like body portion 20 is a portion having a bag-like shape. Because the bag-like body portion 20 is bag-shaped, it is preferable that it has an internal space 23 therein. Furthermore, the bag-like body portion 20 is a portion formed in an annular shape. It is preferable that the bag-like body portion 20 has an inner cavity 25 formed therein by being formed in an annular shape. The bag-like body portion 20 is located distal to the first tubular portion 10.

[0046] As shown in FIGS. 1 to 4, the flow path 40 has a space that allows fluid to be injected up to the bag-shaped body portion 20 .

[0047] The inner cavity of the first shaft 1 is preferably configured by the inner cavity 11 of the first tubular portion 10 and the inner cavity 25 of the bag-like body portion 20 communicating with each other.

[0048] The second shaft 2 includes a second cylindrical portion 50 and an expanded / contracted diameter portion 60 , and is disposed in the inner cavity of the first shaft 1 .

[0049] The second cylindrical portion 50 preferably extends in the longitudinal direction of the first shaft 1. The second cylindrical portion 50 preferably has an inner cavity extending in the longitudinal direction of the first shaft 1.

[0050] The expandable / contractable section 60 is a section that can expand and contract in diameter, and is fixed to the distal part of the second tubular section 50 .

[0051] 4, a first portion 61, which is a part of the expandable / contractable section 60, is located in the lumen of the first shaft 1, and a second portion 62, which is a portion of the expandable / contractable section 60 located distal to the first portion 61, is located outside the first shaft 1. Furthermore, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular section 10, and the outer surface of the first portion 61 is inscribed in the first shaft 1. With the above configuration, the length of the expandable / contractable section 60 that contacts the treatment area can be easily adjusted to a desired length.

[0052] 1 and 3, when the diameter-expanding section 60 is not disposed in the lumen 25 at the distal end of the bag-shaped body section 20, the minimum inner diameter of the bag-shaped body section 20 when the bag-shaped body section 20 is pressurized by injecting fluid into the flow path 40 is configured to be larger than the minimum inner diameter of the bag-shaped body section 20 when no pressurization is performed by injecting fluid into the flow path 40. This causes the minimum inner diameter of the bag-shaped body section 20 to be larger when it is pressurized.

[0053] The catheter 100 can be used, for example, by inserting the distal end of the first shaft 1 to a treatment site, and then protruding a portion of the expandable / contractable section 60 disposed in the lumen of the first shaft 1 from the first shaft 1. When transporting the first shaft 1 to the treatment site, as shown in FIG. 1 , the first shaft 1 is not pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-like body portion 20 is smaller than the minimum inner diameter of the bag-like body portion 20 when the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40, making it easier to reduce the outer diameter of the bag-like body portion 20. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. After transporting the first shaft 1 to the treatment site, as shown in FIG. 3 , the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-shaped body portion 20 is larger than the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injection of fluid into the flow path 40 has not been performed. This makes it easier to protrude a portion of the expandable / contractable portion 60 from the expanded-diameter bag-shaped body portion 20. After the bag-shaped body portion 20 is pressurized by injection of fluid into the flow path 40, as shown in FIG. 4 , the first portion 61 is located in the lumen of the first shaft 1, the second portion 62 is located outside the first shaft 1, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular portion 10, and the outer surface of the first portion 61 is inscribed within the first shaft 1. This makes it easier to adjust the length of the expandable / contractable portion 60 that contacts the treatment site to a desired length.

[0054] The first cylindrical portion 10 is preferably flexible, which allows the first cylindrical portion 10 to be easily deformed to conform to the shape of the body cavity. In addition, the first cylindrical portion 10 is preferably elastic in order to maintain its shape.

[0055] The first tubular portion 10 may be a hollow body formed by arranging one or more wires in a predetermined pattern; a hollow body having a resin coating on at least one of the inner and outer surfaces; a resin tube; or a combination thereof, such as a combination of these, connected in the longitudinal direction. Examples of hollow bodies having wires arranged in a predetermined pattern include a tubular body having a mesh structure in which wires are woven, or a coil in which wires are wound. The wires may be solid or twisted. The resin tube may be manufactured by extrusion molding, for example. When the first tubular portion 10 is a resin tube, the resin tube may be single-layered or multi-layered. In the longitudinal direction x of the first tubular portion 10 or the circumferential direction of the first tubular portion 10, a portion of the first tubular portion 10 may be composed of a single layer, and other portions may be composed of multiple layers.

[0056] The first cylindrical portion 10 can be made of, for example, a synthetic resin such as polyolefin resin (e.g., polyethylene or polypropylene), polyamide resin (e.g., nylon), polyester resin (e.g., PET), aromatic polyether ketone resin (e.g., PEEK), polyether polyamide resin, polyurethane resin, polyimide resin, or fluororesin (e.g., PTFE, PFA, or ETFE), or a metal such as stainless steel, carbon steel, or nickel-titanium alloy. These may be used alone or in combination of two or more.

[0057] The first cylindrical portion 10 preferably has a distal end 10 a and a proximal end 10 b. The first cylindrical portion 10 also preferably has an inner surface 10 c facing the lumen 11 of the first cylindrical portion 10 and an outer surface 10 d facing the outside of the first cylindrical portion 10.

[0058] The outer surface 10d of the first cylindrical portion 10 is preferably coated with a hydrophilic polymer, which makes it easier to insert the first cylindrical portion 10 into a body cavity. Examples of hydrophilic polymers include poly (2-hydroxyethyl methacrylate), polyacrylamide, polyvinylpyrrolidone, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers, and polyethylene glycol.

[0059] The inner surface 10c of the first tubular portion 10 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin, or the entire inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin. This makes the first tubular portion 10 more easily slippery relative to components placed in the lumen 11 of the first tubular portion 10, thereby making it easier to improve the operability of the catheter 100.

[0060] The outer diameter of the first cylindrical portion 10 can be, for example, 1.0 mm or more, 1.1 mm or more, 1.2 mm or more, etc. The outer diameter of the first cylindrical portion 10 can be, for example, 5.0 mm or less, 4.0 mm or less, 3.0 mm or less, etc., but is preferably 2.0 mm or less.

[0061] The inner diameter of the first cylindrical portion 10 can be, for example, 4.0 mm or less, 3.8 mm or less, 3.5 mm or less, etc. The inner diameter of the first cylindrical portion 10 can be, for example, 0.4 mm or more, 0.5 mm or more, 0.6 mm or more, etc., but is preferably 0.8 mm or more, and more preferably 1.2 mm or more. The inner diameter of the first cylindrical portion 10 is also preferably large enough to allow the second shaft 2 to pass through.

[0062] As shown in Figure 6, the first tubular portion 10 has a distal opening 11a at a distal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10, and may have a proximal opening 11b at a proximal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10.

[0063] As shown in Figures 5 and 6, the first tubular portion 10 can be configured to have a tapered region 13 in the proximal portion of the first tubular portion 10, whose length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x of the first tubular portion 10 decreases toward the proximal side.

[0064] 6 , it is preferable that a proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in the tapered region 13. It is more preferable that the proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in a portion that slopes so that the length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x decreases toward the proximal side. With this configuration, for example, the guidewire 4 or the second shaft 2 can be inserted into and removed from the lumen 11 of the first tubular portion 10 through the proximal opening 11b.

[0065] 5 and 6 , the first shaft 1 may further include a third tubular portion 70. A distal portion of the third tubular portion 70 is fixed to a proximal portion of the reduced diameter region 13, and a lumen 71 of the third tubular portion 70 and the flow path 40 can be configured to communicate with each other.

[0066] The third cylindrical portion 70 is a cylindrical portion having an inner cavity 71. It is preferable that the maximum outer diameter of the third cylindrical portion 70 is smaller than the maximum outer diameter of the first cylindrical portion 10. Furthermore, the minimum outer diameter of the third cylindrical portion 70 may be smaller than the minimum outer diameter of the first cylindrical portion 10.

[0067] For the configuration of the third cylindrical portion 70, such as the material constituting the third cylindrical portion 70, reference can be made to the description of the first cylindrical portion 10. The material constituting the third cylindrical portion 70 and the material constituting the first cylindrical portion 10 may be the same or different.

[0068] The outer diameter of the third cylindrical portion 70 can be, for example, 0.60 mm or more, 0.65 mm or more, 0.70 mm or more, etc. The outer diameter of the third cylindrical portion 70 can be, for example, 3.00 mm or less, 2.95 mm or less, 2.90 mm or less, etc., but is preferably 1.00 mm or less.

[0069] The inner diameter of the third cylindrical portion 70 can be, for example, 2.50 mm or less, 2.45 mm or less, 2.35 mm or less, etc. The inner diameter of the third cylindrical portion 70 can be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc., but is preferably 0.50 mm or more.

[0070] The length from the distal end of the third cylindrical portion 70 to the proximal end of the third cylindrical portion 70 can be, for example, 100 mm or more, 150 mm or more, 200 mm or more, etc. Furthermore, the length from the distal end of the third cylindrical portion 70 to the proximal end of the third cylindrical portion 70 can be, for example, 2400 mm or less, 2350 mm or less, 2300 mm or less, etc.

[0071] When the first shaft 1 includes the third cylindrical portion 70, the length from the distal end 10a of the first cylindrical portion 10 to the proximal end 10b of the first cylindrical portion 10 can be, for example, 30 mm or more, 35 mm or more, 40 mm or more, etc. Furthermore, the length from the distal end 10a of the first cylindrical portion 10 to the proximal end 10b of the first cylindrical portion 10 can be, for example, 700 mm or less, 650 mm or less, 600 mm or less, etc.

[0072] It is preferable that a lubricating coating layer containing PTFE, PFA, or the like is formed on the outer surface of the third cylindrical portion 70. This makes it easier to insert the third cylindrical portion 70 into a body cavity.

[0073] The third cylindrical portion 70 may be provided with a position indication marker for indicating the length of the inserted portion when the first shaft 1 is inserted into a body cavity. The position indication marker may be formed, for example, by inserting the third cylindrical portion 70 into the inner cavity of a marker tube and welding it, or may be formed by peeling off a part of the lubricating coating layer containing the above-mentioned PTFE, PFA, or the like.

[0074] The position indication markers can be provided, for example, at positions 600 mm, 900 mm, 1200 mm, etc. from the distal end of the first shaft 1.

[0075] It is preferable that the distal portion of the third tubular portion 70 and the proximal portion of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is more preferable that the distal end of the third tubular portion 70 and the proximal end of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is preferable that the lumen 71 of the third tubular portion 70 does not communicate with the lumen 11 of the first tubular portion 10.

[0076] 5, the catheter 100 preferably further includes a hub 72 connected to the proximal end of the first shaft 1. The hub 72 may be connected to the third cylindrical portion 70. In this case, the hub 72 preferably includes a port therein that communicates with the lumen 71 of the third cylindrical portion 70, and a fluid can be injected into the lumen 71 of the third cylindrical portion 70 via the port.

[0077] Although not shown, the first shaft 1 may not include the third cylindrical portion 70, and the proximal end 10b of the first cylindrical portion 10 may be directly connected to the hub 72. In this case, it is preferable that the hub 72 has a port therein that communicates with the flow path 40, and that a fluid can be injected into the flow path 40 via the port.

[0078] The material constituting the bag-shaped body portion 20 can be, for example, any of the materials listed as being constituting the first tubular portion 10. The material constituting the bag-shaped body portion 20 and the material constituting the first tubular portion 10 may be the same or different.

[0079] As shown in Figures 5 and 6, the proximal portion of the bag-shaped body portion 20 may be connected to the distal portion of the first tubular portion 10, or the proximal end of the bag-shaped body portion 20 may be connected to the distal end 10a of the first tubular portion 10.

[0080] The minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. In particular, as shown in FIG. 8 , when pressurization by injecting a fluid into the flow path 40 is not performed, the minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. This makes it less likely that the first shaft 1 will get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. From the viewpoint of enhancing this effect, as shown in FIG. 8 , it is more preferable that the maximum outer diameter of the bag-shaped body portion 20 is equal to or smaller than the outer diameter of the first tubular portion 10 when pressurization by injecting a fluid into the flow path 40 is not performed. Note that, as shown in FIG. 9 , even when the bag-shaped body portion 20 is pressurized by injecting a fluid into the flow path 40, the minimum outer diameter of the bag-shaped body portion 20 may be smaller than the outer diameter of the first tubular portion 10. As shown in Figure 4, when the expandable diameter section 60 is arranged in the inner cavity 25 of the bag-shaped body section 20 and the expandable diameter section 60 expands, the maximum outer diameter of the bag-shaped body section 20 may be greater than or equal to the outer diameter of the first tubular section 10.

[0081] The bag-shaped body portion 20 provided distal to the distal end 10a of the first tubular portion 10 preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 8 , when pressurization by injecting a fluid into the flow path 40 is not performed, the bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 8 , when pressurization by injecting a fluid into the flow path 40 is not performed, the entire bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. Note that, as shown in FIG. 9 , when pressurization by injecting a fluid into the flow path 40 is performed, the bag-shaped body portion 20 may have a tapered portion whose outer diameter decreases toward the distal side. 9, the entire bag-shaped body portion 20 may be a tapered portion in which the outer diameter decreases toward the distal side when the bag-shaped body portion 20 is pressurized by injection of a fluid into the flow path 40. As shown in FIG. 4, when the expandable / contractable diameter portion 60 is disposed in the lumen 25 of the bag-shaped body portion 20 and the expandable / contractable diameter portion 60 expands in diameter, the bag-shaped body portion 20 may have a tapered portion in which the outer diameter decreases toward the proximal side, or the entire bag-shaped body portion 20 may be a tapered portion in which the outer diameter decreases toward the proximal side.

[0082] Although the bag-shaped body portion 20 is formed in an annular shape, it may also have a hollow truncated cone shape, as shown in Figures 5 to 7. Although not shown, the bag-shaped body portion 20 may also have a hollow truncated polygonal pyramid shape, or a shape that combines a hollow truncated cone and a hollow truncated polygonal pyramid, for example, a shape in which a hollow truncated cone and a hollow truncated polygonal pyramid are connected in the longitudinal direction x of the first tubular portion 10.

[0083] When the expandable / contractable section 60 is not disposed in the lumen 25 at the distal end of the bag-shaped body section 20, the minimum inner diameter of the bag-shaped body section 20 when the bag-shaped body section 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 is preferably larger than the minimum inner diameter of the bag-shaped body section 20 when no pressurization is performed by injecting a fluid into the flow path 40. This increases the minimum inner diameter of the bag-shaped body section 20 when it is pressurized to a predetermined pressure or higher.

[0084] 6 to 9, the bag-shaped body portion 20 can be configured to have an inner surface portion 21 facing the lumen 25 of the bag-shaped body portion 20 and an outer surface portion 22 facing the exterior of the bag-shaped body portion 20. The inner surface portion 21 has an inner surface facing the lumen 25, and the outer surface portion 22 has an outer surface facing the exterior. The inner surface portion 21 has a distal end 21a and a proximal end 21b. The outer surface portion 22 has a distal end 22a and a proximal end 22b. It is preferable that an internal space 23 exists between the inner surface portion 21 and the outer surface portion 22.

[0085] It is preferable that the elongation percentage (%) of the length from the distal end 21 a to the proximal end 21 b of the inner surface portion 21 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 is greater than the elongation percentage (%) of the length from the distal end 22 a to the proximal end 22 b of the outer surface portion 22 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40. With the above-described configuration, when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid, the inner surface portion 21, which is more elongate than the outer surface portion 22, stretches, and the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. This allows the minimum inner diameter of the bag-shaped body portion 20 when it is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 to be larger than the minimum inner diameter of the bag-shaped body portion 20 when it is not pressurized by injecting a fluid into the flow path 40. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 8 to the state shown in FIG. 9. Therefore, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site, it is possible to make the second shaft 2 easily protrude from the expanded diameter portion. The elongation rate (%) is calculated by dividing the length of each portion after pressurization by the length of each portion before pressurization.

[0086] The inner surface portion 21 and the outer surface portion 22 may be made of the same material or different materials.

[0087] When the inner surface portion 21 and the outer surface portion 22 are made of the same material, for example, it is preferable that the thickness of the inner surface portion 21 is thinner than the thickness of the outer surface portion 22. This makes the inner surface portion 21 more stretchable than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in Fig. 8 to the state shown in Fig. 9. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0088] When the inner surface portion 21 and the outer surface portion 22 are made of different materials, for example, it is preferable that the elongation rate of the material making up the inner surface portion 21 be higher than that of the material making up the outer surface portion 22. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material making up the inner surface portion 21 and a sample made of the material making up the outer surface portion 22, formed to the same shape as the sample, are prepared, and then the samples are gripped at one end and the other end so that the grip width is the same length and pulled with the same strength (N). This makes the inner surface portion 21 more elongate than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to increase compared to before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in FIG. 8 to the state shown in FIG. 9. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0089] In a cross section of the first tubular portion 10 parallel to the longitudinal direction x, the angle α formed between the inner surface portion 21 and the outer surface portion 22 when pressurization by injecting a fluid into the flow path 40 is not performed is preferably an acute angle, as shown in FIG. 8 . The angle α may be 85° or less, 80° or less, or 70° or less. The angle α may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity.

[0090] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, when the first tubular portion 10 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40, the angle β between the inner surface portion 21 and the outer surface portion 22 is preferably an acute angle, as shown in FIG. 9 . The angle β may be 85° or less, 80° or less, or 70° or less. The angle β may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the thickness of the distal end of the bag-shaped body portion 20. In other words, it makes it easier to shorten the length between the inner surface of the inner surface portion 21 and the outer surface of the outer surface portion 22. Therefore, it makes it easier to increase the inner diameter of the distal end of the bag-shaped body portion 20 when the first tubular portion 10 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40. Therefore, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to a treatment site, it makes it easier to protrude the second shaft 2 from the expanded diameter portion.

[0091] As shown in Figures 6 and 7 , the internal space 23 is a space formed within the wall that constitutes the annular bag-shaped body portion 20. In the example shown in Figures 6 and 7 , the internal space 23 is a space that exists within the wall that forms the lumen 25 of the bag-shaped body portion 20. As shown in Figures 6 and 7 , the internal space 23 preferably exists throughout the entire circumferential direction within the wall of the bag-shaped body portion 20. In other words, the internal space 23 is preferably a space that is circumferentially connected within the wall of the bag-shaped body portion 20. Although not shown, the internal space 23 may exist only partially within the circumferential direction within the wall of the bag-shaped body portion 20.

[0092] It is preferable that the internal space 23 does not communicate with the lumen 11 of the first tubular portion 10. It is also preferable that the internal space 23 does not communicate with the lumen 25 of the bag-shaped body portion 20. This makes it easier for the fluid injected into the flow path 40 to efficiently flow into the internal space 23 formed in the bag-shaped body portion 20.

[0093] 8 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when pressurization by injection of a fluid into the flow path 40 is not being performed, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0094] 9 , when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injection of a fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, when the minimum internal diameter of the bag-shaped body portion 20 increases due to pressurization to a predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0095] 8 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when pressurization by injection of a fluid into the flow path 40 is not being performed, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, when the first shaft 1 is transported to the treatment site, it is less likely to get caught on the wall of the body cavity, which makes it easier to prevent damage to the wall of the body cavity and also makes it easier to improve passability through the body cavity.

[0096] 9 , when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injection of a fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, when the minimum inner diameter of the bag-shaped body portion 20 increases due to pressurization to a predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0097] The length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when no pressurization is performed by injecting a fluid into the flow path 40 and the length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 may be the same or different.

[0098] The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0099] The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-like body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-like body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0100] The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed is preferably a size that allows the guide wire 4 to be inserted therethrough. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 30% or more, 35% or more, or 40% or more of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 70% or less, 65% or less, or 60% or less of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc. Furthermore, the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 2.00 mm or less, 1.95 mm or less, 1.90 mm or less, etc.

[0101] 8 , in a state where no pressurization is performed by injecting a fluid into the flow path 40, it is preferable that the inner diameter of the bag-shaped body portion 20 is smallest at the distal end of the bag-shaped body portion 20. In a state where pressurization is performed at a predetermined pressure or higher by injecting a fluid into the flow path 40, it may be the proximal end or the distal end of the bag-shaped body portion 20 where the inner diameter is smallest.

[0102] The minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 0.31 mm or more, 0.36 mm or more, 0.41 mm or more, etc. Furthermore, the minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 3.00 mm or less, 2.90 mm or less, 2.80 mm or less, etc.

[0103] As shown in Fig. 8, in a state where no pressurization is performed by injecting a fluid into the flow path 40, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter. As shown in Fig. 9, in a state where pressurization is performed to a predetermined pressure or higher by injecting a fluid into the flow path 40, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter.

[0104] 1 to 4 and 8 to 12, the first tubular portion 10 has a wall 12 that forms the lumen 11, and the flow path 40 can be configured to be formed within the wall 12 of the first tubular portion 10. This configuration eliminates the need to provide a separate member for forming the flow path 40, making it easier to make the catheter 100 thinner.

[0105] 8 and 10, the first tubular portion 10 may have a first outer cylinder 15 and a first inner cylinder 14 disposed in the lumen of the first outer cylinder 15, and the flow path 40 may be a space defined by an inner surface 15c of the first outer cylinder 15 and an outer surface 14d of the first inner cylinder 14. This configuration eliminates the need to provide a separate member for forming the flow path 40, making it easier to make the catheter 100 thinner.

[0106] The thickness of the first outer cylinder 15 may be 0.010 mm or more, 0.015 mm or more, 0.020 mm or more, etc. The thickness of the first outer cylinder 15 may be 0.500 mm or less, 0.450 mm or less, 0.400 mm or less, etc.

[0107] The thickness of the first inner cylinder 14 can be 0.010 mm or more, 0.015 mm or more, 0.020 mm or more, etc. The thickness of the first inner cylinder 14 can be 0.500 mm or less, 0.450 mm or less, 0.400 mm or less, etc.

[0108] 10 , the distance between the inner surface 15c of the first outer cylinder 15 and the outer surface 14d of the first inner cylinder 14 is preferably 0.01 mm or more and 1.0 mm or less, which can reduce pressure loss when delivering fluid to the distal end through the flow path 40.

[0109] The first outer cylinder 15 may have a distal end and a proximal end, and may have a lumen extending in the longitudinal direction x. The same applies to the first inner cylinder 14.

[0110] When the bag-shaped body portion 20 changes from a state in which it is not pressurized by injecting a fluid into the flow path 40 to a state in which it is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40, the elongation percentage (%) of the length from the distal end 21a to the proximal end 21b of the inner surface portion 21 is preferably greater than the elongation percentage (%) of the length from the distal end 10a to the proximal end 10b of the first tubular portion 10. This configuration is particularly preferable when the flow path 40 is formed within the wall 12 of the first tubular portion 10. The higher elongation percentage (%) of the bag-shaped body portion 20 than that of the first tubular portion 10 makes it possible to make the first tubular portion 10 less susceptible to deformation by fluid pressure, thereby facilitating the stable supply of fluid injected into the flow path 40 to the bag-shaped body portion 20.

[0111] 11 and 12 , the flow path 40 may extend linearly in the longitudinal direction x of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10. Although not shown, the flow path 40 may be formed in a wave shape within the wall 12 of the first cylindrical portion 10, or the flow path 40 may be formed in a spiral shape that circles around the inner cavity 11 of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10.

[0112] 11 and 12 , when the flow path 40 extends linearly in the longitudinal direction x of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10, it is preferable that the internal space 23 that is continuous throughout the entire circumferential direction of the first cylindrical portion 10 within the wall of the bag-shaped body portion 20 communicates with the linear flow path 40. This allows the fluid injected into the flow path 40 to be injected into the internal space 23 of the bag-shaped body portion 20.

[0113] The flow path 40 may be formed not only within the wall 12 of the first cylindrical portion 10, but also by providing a component separate from the first cylindrical portion 10. For example, as shown in FIGS. 13 and 14 , the flow path 40 may be formed by a fourth cylindrical portion 41 disposed in the lumen 11 of the first cylindrical portion 10. The fourth cylindrical portion 41 is a cylindrical portion having a lumen, and the lumen of the fourth cylindrical portion 41 is the flow path 40. By disposing the fourth cylindrical portion 41 in the lumen 11 of the first cylindrical portion 10, the catheter 100 can be made thinner. Although not shown, the fourth cylindrical portion 41 may also be disposed outside the first cylindrical portion 10.

[0114] When the flow path 40 is formed by the fourth cylindrical portion 41, it is preferable that the distal end portions of the bag-shaped body portion 20 and the fourth cylindrical portion 41 are fixed together, as shown in Figures 13 and 14. It is also preferable that the bag-shaped body portion 20 has a hole 24 that connects the flow path 40 with the internal space 23. This allows the fluid injected into the flow path 40 formed by the fourth cylindrical portion 41 to be injected into the internal space 23 of the bag-shaped body portion 20.

[0115] For the configuration of the fourth cylindrical portion 41, such as the material constituting the fourth cylindrical portion 41, reference can be made to the portion described for the first cylindrical portion 10. The material constituting the first cylindrical portion 10, the material constituting the third cylindrical portion 70, and the material constituting the fourth cylindrical portion 41 may be the same or different.

[0116] The fluid to be introduced into the flow channel 40 is not particularly limited, but may be, for example, a liquid such as physiological saline, a contrast medium, or a mixture thereof, or a gas such as air, nitrogen, or carbon dioxide.

[0117] The fluid is preferably radiopaque. By injecting a radiopaque fluid, the distal end of the bag-shaped body portion 20 can be more easily visualized, and therefore the proximal end of the expandable diameter portion 60 that contacts the treatment site can be more easily visualized.

[0118] 1 and 2 , a reinforcing member 16 may be disposed between the flow path 40 and the lumen 11 of the first tubular portion 10. This makes it possible to more easily prevent the flow path 40 from collapsing even when a member that expands in diameter is disposed in the lumen of the first shaft 1.

[0119] The reinforcing member 16 may be made of metal. The reinforcing member 16 may be made of resin. As the metal or resin constituting the reinforcing member 16, the materials listed as the materials constituting the first tubular portion 10 can be used.

[0120] The reinforcing member 16 is preferably configured by a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof. The wire may be a solid wire or a twisted wire.

[0121] 15 , in a state where pressurization by injection of a fluid into the flow path 40 is not performed, the first tubular portion 10 may have a protrusion 17 that protrudes inward in the radial direction y of the first tubular portion 10. In other words, the protrusion 17 is a portion that protrudes inward in the radial direction y of the first tubular portion 10 regardless of whether or not a fluid is injected into the flow path 40. This makes it easier to suppress movement of a member disposed in the lumen of the first shaft 1 in the longitudinal direction x of the first tubular portion 10.

[0122] A radiopaque portion 3 may be provided in at least one of the sac-shaped body portion 20 and a region of the first tubular portion 10 extending 10 cm proximally from the distal end 10a. This configuration makes it possible to visually confirm the position of the distal end of the catheter 100 using an X-ray imaging device. Figures 13 and 14 show an embodiment in which the radiopaque portion 3 is provided in the first tubular portion 10, while Figures 1, 3, and 4 show an embodiment in which the radiopaque portion 3 is provided in the sac-shaped body portion 20.

[0123] The radiopaque portion 3 may be provided only in the bag-shaped body portion 20. The radiopaque portion 3 may be provided only in a region from the distal end 10a of the first cylindrical portion 10 to a position 10 cm proximal to the bag-shaped body portion 20. The radiopaque portion 3 may be provided both in the bag-shaped body portion 20 and in a region from the distal end 10a of the first cylindrical portion 10 to a position 10 cm proximal to the bag-shaped body portion 20.

[0124] As shown in Fig. 4, it is preferable that an X-ray opaque portion 3 is provided at the distal end of the bag-shaped body portion 20. This makes it easier to visualize the proximal end of the expandable / contractable portion 60 that contacts the treatment site.

[0125] The shape of the radiopaque portion 3 is preferably tubular, and examples thereof include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross section with a notch in the tube, and a coil shape with a wound wire.

[0126] The material constituting the radiopaque portion 3 may be, for example, a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt-chromium alloy, and may be a form in which radiopaque particles such as barium sulfate are dispersed in the first tubular portion 10, the bag-shaped body portion 20, or a separately provided resin member.

[0127] 16 and 17 , the first shaft 1 may include a bulging portion 30 that bulges when pressurized by injection of a fluid into the flow path 40. The bulging portion 30 is a portion that bulges inward in the radial direction y of the first tubular portion 10 or outward in the radial direction y.

[0128] 16 when pressurized by injection of fluid into the flow path 40, the bulging portion 30 may be configured to bulge inward in the radial direction y of the first tubular portion 10. When pressurized, the bulging portion 30 bulges, making it easier to come into contact with the second shaft 2 and making it easier to suppress movement of the second shaft 2 in the longitudinal direction of the first shaft 1.

[0129] 17 when pressurized by injection of fluid into the flow path 40, the bulging portion 30 may be configured to bulge outward in the radial direction y of the first tubular portion 10. The bulging portion 30 bulges when pressurized, making it easier to bring the bulging portion 30 into contact with the wall of the body cavity and making it easier to suppress movement of the first shaft 1 within the body cavity.

[0130] The material constituting the bulging portion 30 may be any of the materials listed as the materials constituting the first tubular portion 10 and the materials listed as the materials constituting the balloon described below. The material constituting the bulging portion 30 and the material constituting the first tubular portion 10 may be the same or different.

[0131] The flow path 40 for injecting fluid into the bulging portion 30 and the flow path 40 for injecting fluid into the bag-shaped body portion 20 may be provided separately. The flow path 40 for injecting fluid into the bulging portion 30 and the flow path 40 for injecting fluid into the bag-shaped body portion 20 may be connected to each other, or the flow path 40 for injecting fluid into the bulging portion 30 and the flow path 40 for injecting fluid into the bag-shaped body portion 20 may partially overlap each other.

[0132] 16 and 17 , the bulging portion 30 may be a portion that bulges inward in the radial direction y or outward in the radial direction y of the first tubular portion 10 by expanding a portion of the first tubular portion 10. Although not shown, the bulging portion 30 may have a configuration separate from the first tubular portion 10. For example, the bulging portion 30 may be a bag-like member that is disposed in the lumen 11 of the first tubular portion 10 or outside the first tubular portion 10, and the fluid may be injected through a tubular member connected to the bag-like member. In this case, the lumen of the tubular member functions as the flow path 40.

[0133] 16 and 17 , when the bulging portion 30 is a portion that bulges inward in the radial direction y or outward in the radial direction y of the first tubular portion 10 due to expansion of a portion of the first tubular portion 10, it is preferable that the portion of the first tubular portion 10 that constitutes the bulging portion 30 is thinner than the portion of the first tubular portion 10 other than the bulging portion 30. This makes the portion of the first tubular portion 10 that constitutes the bulging portion 30 more easily stretchable than the portion of the first tubular portion 10 other than the bulging portion 30, making it easier to bulge the portion of the first tubular portion 10 that constitutes the bulging portion 30. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 1 to the state shown in FIGS. 16 and 17 .

[0134] 16 and 17 , when the bulging portion 30 is a portion of the first cylindrical portion 10 that bulges inward in the radial direction y or outward in the radial direction y due to the expansion of a portion of the first cylindrical portion 10, it is preferable that the elongation rate of the material constituting the bulging portion 30 of the first cylindrical portion 10 be higher than the elongation rate of the material constituting the rest of the first cylindrical portion 10. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material constituting the bulging portion 30 of the first cylindrical portion 10 and a sample formed to the same shape as the sample made of the material constituting the rest of the first cylindrical portion 10 other than the bulging portion 30 are prepared, and one end and the other end of each sample are gripped to the same length and pulled with the same strength (N). This makes the bulging portion 30 more elongate than the portion other than the bulging portion 30, making the bulging portion 30 more likely to expand when pressurized. In the above example, the first shaft 1 is likely to change from the state shown in FIG. 1 to the states shown in FIGS.

[0135] The bulging portion 30 may be present on a portion of the first cylindrical portion 10 in the circumferential direction, or may be present on the entire first cylindrical portion 10 in the circumferential direction.

[0136] The first shaft 1 may have only one bulging portion 30 or may have a plurality of bulging portions 30 .

[0137] The bulging height 30L of the bulging portion 30 in the radial direction y of the first cylindrical portion 10 may vary in the circumferential direction of the first cylindrical portion 10. The bulging height 30L of the bulging portion 30 refers to the length of the bulging portion in the radial direction y of the first cylindrical portion 10. The bulging height 30L of the bulging portion 30 in the radial direction y of the first cylindrical portion 10 may be constant and not vary in the circumferential direction of the first cylindrical portion 10.

[0138] 16 , when the bulging portion 30 is a portion that bulges inward in the radial direction y of the first tubular portion 10 due to a portion of the first tubular portion 10 expanding, the frictional force of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y is preferably higher than the frictional force of the inner surface 10c of the first tubular portion 10 facing the lumen 11 of the first tubular portion 10, which constitutes the first tubular portion 10 other than the bulging portion 30. It is more preferable that the frictional force of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y when the first tubular portion 10 is pressurized by the injection of fluid into the flow path 40 is higher than the frictional force of the inner surface 10c of the first tubular portion 10 facing the lumen 11 of the first tubular portion 10, which constitutes the first tubular portion 10 other than the bulging portion 30 when the first tubular portion 10 is pressurized by the injection of fluid into the flow path 40. The frictional force of each surface can be adjusted by changing the coating, surface roughness, material, etc. With the above configuration, it is possible to easily suppress movement of the second shaft 2 and the guide wire 4 disposed in the lumen of the first shaft 1 in the longitudinal direction x of the first tubular portion 10.

[0139] As shown in FIG. 17 , when the bulging portion 30 is a portion that bulges outward in the radial direction y of the first tubular portion 10 due to partial expansion of the first tubular portion 10, the frictional force of the outer surface of the bulging portion 30 is preferably higher than the frictional force of the outer surface 10d of the first tubular portion 10 that constitutes the first tubular portion 10 other than the bulging portion 30. It is more preferable that the frictional force of the outer surface of the bulging portion 30 when pressurized by the injection of fluid into the flow path 40 is higher than the frictional force of the outer surface 10d of the first tubular portion 10 that constitutes the first tubular portion 10 other than the bulging portion 30 when pressurized by the injection of fluid into the flow path 40. The frictional force of each surface can be adjusted by changing the coating, surface roughness, material, etc. This configuration makes it easier to suppress movement of the first shaft 1 within the body cavity.

[0140] 16 and 17 , the bulging portion 30 is preferably located proximal to the proximal end of the bag-shaped body portion 20. Alternatively, the bulging portion 30 may be located proximal to the distal end 10 a of the first tubular portion 10. The bulging portion 30 is preferably provided in the distal portion of the first tubular portion 10.

[0141] The protruding height 17L of the protruding portion 17 and the protruding height 30L of the bulging portion 30 may be the same or different. The protruding height 17L of the protruding portion 17 may be higher than the protruding height 30L of the bulging portion 30. The protruding height 17L of the protruding portion 17 may be lower than the protruding height 30L of the bulging portion 30. The protruding height 17L of the protruding portion 17 refers to the length of the protruding portion in the radial direction y of the first cylindrical portion 10. The protruding height 30L of the bulging portion 30 refers to the length of the bulging portion in the radial direction y of the first cylindrical portion 10.

[0142] The second cylindrical portion 50 may have a lumen extending in the longitudinal direction of the first shaft 1. The lumen of the second cylindrical portion 50 may be used as a passage for inserting a guide wire 4 or the like, as shown in Figures 1 to 4 .

[0143] As shown in Figures 1 to 4, the second tubular portion 50 may be configured to include a second outer tube 52 arranged in the inner cavity 11 of the first tubular portion 10, and a second inner tube 51 arranged in the inner cavity of the second outer tube 52.

[0144] For the configuration of the second cylindrical portion 50, such as the material constituting the second cylindrical portion 50, reference can be made to the portion described for the first cylindrical portion 10. The material constituting the first cylindrical portion 10, the material constituting the third cylindrical portion 70, the material constituting the fourth cylindrical portion 41, and the material constituting the second cylindrical portion 50 may be the same or different. Note that the material constituting the second inner cylinder 51 and the material constituting the second outer cylinder 52 may be the same or different.

[0145] The inner surface of the second inner tube 51 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface of the second inner tube 51 may be made of a fluororesin or a polyolefin resin, or the entire inner surface of the second inner tube 51 may be made of a fluororesin or a polyolefin resin. This allows the second inner tube 51 to slide easily over the guidewire 4, thereby making it easier to improve the operability of the catheter 100.

[0146] A control mechanism that suppresses movement of the second shaft 2 in the longitudinal direction x of the first tubular portion 10 may be provided in the proximal portion of the catheter 100. With this configuration, the control mechanism makes it possible to transport the catheter 100 to the treatment site while suppressing movement of the second shaft 2 in the longitudinal direction x of the first tubular portion 10, thereby making it easier to transport the catheter 100 to the treatment site.

[0147] Although not shown, one example of the control mechanism is a mode in which the third tubular portion 70 is provided with a gripping member capable of gripping the second tubular portion 50. By gripping the second tubular portion 50 with the gripping member, it is possible to temporarily suppress movement of the second tubular portion 50 in the longitudinal direction x of the first tubular portion 10. Then, by detaching the second tubular portion 50 from the gripping member, it is possible to return the second tubular portion 50 to a state in which it is movable relative to the first shaft 1. Examples of the gripping member include a rubber member provided with a slit that grips the second tubular portion 50 by pinching it, and a clip made of rigid resin.

[0148] The expandable / contractable section 60 may be, for example, a balloon or a stent that can expand and contract in diameter.

[0149] The balloon is preferably made of a resin. Examples of resins constituting the balloon include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, vinyl chloride resins, silicone resins, and natural rubber. These may be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, and polyurethane resins are preferably used. Elastomer resins can be used from the viewpoint of thinning and flexibility of the balloon.

[0150] 1, 3, and 4, when the second tubular portion 50 has a second inner cylinder 51 and a second outer cylinder 52, and the expandable / contractable portion 60 is a balloon, it is preferable that the distal end of the expandable / contractable portion 60 is fixed to the distal portion of the second inner cylinder 51, and the proximal end of the expandable / contractable portion 60 is fixed to the distal portion of the second outer cylinder 52. The expandable / contractable portion 60 can be expanded by injecting a fluid into the space surrounded by the second inner cylinder 51 and the second outer cylinder 52.

[0151] A stent is a tubular structure that can expand and contract in diameter, for example, composed of a mesh or other network structure. It is preferable that the stent expands and contracts, for example, in its circumferential and axial directions. Examples of stents include a coil-shaped stent made of a single linear metal or polymeric material, a metal tube or a polymeric tube cut out with a laser or the like, a stent assembled by welding linear members, and a stent made by weaving multiple linear metal members.

[0152] The stent is preferably made of a shape-memory alloy or a shape-memory resin, but may also be made of, for example, stainless steel such as SUS304 or SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, a Ni—Ti alloy, or a Co—Cr alloy.

[0153] The stent may be a self-expanding stent or a balloon-expandable stent.

[0154] The expandable / contractable section 60 preferably uses a balloon or stent having a coating layer formed on its outer surface 63. After the catheter 100 reaches the treatment site, fluid is injected into the flow path 40 to pressurize the sac-shaped body portion 20, increasing the minimum inner diameter of the sac-shaped body portion 20 compared to before pressurization. In the example described above, the catheter 100 changes from the state shown in FIG. 1 to the state shown in FIG. 3 by injecting fluid. After the balloon or stent placed in the lumen of the first shaft 1 in the state shown in FIG. 1 is transported to the treatment site, the minimum lumen of the sac-shaped body portion 20 is enlarged as shown in FIG. 3. This makes it easier to protrude a portion of the second shaft 2 equipped with the balloon or stent from the first shaft 1. This makes it easier to prevent the coating layer provided on the outer surface 63 of the balloon or stent from peeling off when the balloon or stent is placed at the treatment site.

[0155] The coating layer can be formed by applying a coating agent to the outer surface of the balloon or stent. The coating layer may be formed only on a portion of the outer surface of the balloon or stent, or may be formed on the entire outer surface of the balloon or stent.

[0156] For example, the coating layer may include a lubricious coating agent or a biologically active agent.

[0157] Examples of lubricating coating agents include silicone-based coating agents such as silicone and polydimethylsiloxane; acrylic-based coating agents such as sodium (meth)acrylate, butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, octyl (meth)acrylate, and 2,2,2-trifluoroethyl methacrylate; fluorine-based coating agents such as polytetrafluoroethylene; and hydrophilic coating agents such as polyvinylpyrrolidone, hyaluronic acid, and polyethylene glycol.

[0158] Examples of physiologically active agents include paclitaxel, docetaxel, sirolimus, temsirolimus, everolimus, zotarolimus, biolimus A9, cilostazol, cyclosporine, and NF-κB decoy oligonucleotides. A physiologically active agent may be used alone, or multiple physiologically active agents may be used in combination. Furthermore, a balloon or stent may be coated with only a physiologically active agent, or may be coated with a physiologically active agent to which an appropriate additive has been added.

[0159] The length from the distal end to the proximal end of the catheter 100 can be, for example, 200 mm or more, 250 mm or more, 300 mm or more, etc. The length from the distal end to the proximal end of the catheter 100 can be, for example, 2500 mm or less, 2450 mm or less, 2400 mm or less, etc.

[0160] In a state in which the maximum outer diameter of the second portion 62 of the diameter-expanding portion 60 is larger than the maximum outer diameter of the first tubular portion 10, as shown in Figure 4, it is preferable that the maximum inner diameter of the bag-shaped body portion 20 is larger than the maximum inner diameter of the first tubular portion 10. This makes it easier for the bag-shaped body portion 20 to follow the shape of the diameter-expanding portion 60.

[0161] Although not shown, the proximal end of the catheter 100 is provided with the hub 72, a controller used to operate the catheter 100, other devices, and the like, and may further include a mechanism capable of fixing these components so that their relative positions do not change. Preferably, this mechanism is capable of fixing at least two of the hub 72, the controller, and other devices so that their relative positions do not change. Here, being capable of being fixed means that the relative positions of the at least two components can be fixed so that they do not change, and that the fixed state can be released so that the relative positions of the at least two components can be changed.

[0162] (Second embodiment) From here, a second embodiment of the first invention will be described. Note that explanations of the lengths and constituent materials of the members and parts that have already been explained will be omitted. The explanations in the first embodiment can be referred to as appropriate.

[0163] A second embodiment of the first invention is a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction of the first shaft; a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape; a bulging portion bulging radially inward of the first tubular portion; and a flow path having a space in which a fluid can be injected up to the bag-shaped body portion and a space in which a fluid can be injected up to the bulging portion; and a second shaft comprising: a second tubular portion; and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion, wherein a first portion which is a part of the expanding / contracting diameter portion is located in the inner cavity of the first shaft, and a portion of the expanding / contracting diameter portion located distal to the first portion. a second portion positioned outside the first shaft, the maximum outer diameter of the second portion being larger than the maximum outer diameter of the first tubular portion, the outer surface of the first portion being inscribed within the first shaft, and the bulging portion bulging radially inward of the first tubular portion, wherein the bulging portion bulges radially inward of the first tubular portion when pressurized by injecting fluid into the flow path, and when the expandable diameter portion is not positioned in the lumen of the distal end of the bag-like body portion, the minimum inner diameter of the bag-like body portion when pressurized by injecting fluid into the flow path is larger than the minimum inner diameter of the bag-like body portion when not pressurized by injecting fluid into the flow path.

[0164] The overall configuration of the second embodiment will be described with reference to Figures 18 to 36. These figures show a catheter 100 having a first shaft 1 equipped with a first tubular portion 10, a bag-shaped portion 20, a bulging portion 30, and a flow path 40, and a second shaft 2 disposed in the lumen of the first shaft 1. In these figures, the longitudinal direction of the first tubular portion 10 is indicated by x, and the radial direction is indicated by y.

[0165] FIG. 18 is an enlarged cross-sectional view (partial side view) of a distal portion of a catheter according to an embodiment of the present invention, illustrating a state in which pressurization by injection of a fluid into the flow path is not being performed. FIG. 19 is a cross-sectional view of the catheter shown in FIG. 18 taken along line XIX-XIX. FIG. 20 is a cross-sectional view (partial side view) of the catheter shown in FIG. 18 when pressurized by injection of a fluid into the flow path. FIG. 21 is a cross-sectional view (partial side view) of the catheter shown in FIG. 18 when pressurized by injection of a fluid into the flow path. FIG. 22 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 23 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 22. FIG. 24 is a cross-sectional view of the first shaft shown in FIG. 23 taken along line XXIV-XXIV. FIG. 25 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 23 when pressurization by injection of a fluid into the flow path is not being performed. FIG. 26 is a cross-sectional view of the first shaft shown in FIG. 25 when it is pressurized by injecting a fluid into the flow channel. FIG. 27 is a cross-sectional view of the first shaft shown in FIG. 25 when it is pressurized by injecting a fluid into the flow channel. FIG. 28 is a cross-sectional view of the first shaft shown in FIG. 27 taken along line XXVIII-XXVIII. FIG. 29 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 28. FIG. 30 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 28. FIG. 31 is a cross-sectional view of the first shaft shown in FIG. 25 taken along line XXXI-XXXI. FIG. 32 is a cross-sectional view of a modified example of the first shaft shown in FIG. 25. FIG. 33 is a cross-sectional view of the first shaft shown in FIG. 32 taken along line XXXIII-XXXIII. FIG. 34 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 25. Fig. 35 is a cross-sectional view taken along line XXXV-XXXV of the first shaft shown in Fig. 34. Fig. 36 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 25.

[0166] As shown in FIGS. 18 to 21, the catheter 100 has a first shaft 1 and a second shaft 2 .

[0167] The first shaft 1 includes a first cylindrical portion 10 , a bag-shaped portion 20 , a bulging portion 30 , and a flow path 40 .

[0168] As shown in FIGS. 18 to 21, the first shaft 1 has a longitudinal direction and an inner cavity extending in the longitudinal direction.

[0169] 18 to 21 , the first shaft 1 has a first tubular portion 10 extending in the longitudinal direction of the first shaft 1. The first tubular portion 10 has a longitudinal direction x and a radial direction y that is a direction perpendicular to the longitudinal direction x. The first tubular portion 10 preferably has an inner cavity 11 extending in the longitudinal direction x of the first tubular portion 10.

[0170] As shown in Figures 18, 20, and 21, the bag-like body portion 20 is a portion having a bag-like shape. Because the bag-like body portion 20 is bag-shaped, it is preferable that it has an internal space 23 therein. Furthermore, the bag-like body portion 20 is a portion formed in an annular shape. It is preferable that the bag-like body portion 20 has an inner cavity 25 formed therein by being formed in an annular shape. The bag-like body portion 20 is located distal to the first tubular portion 10.

[0171] As shown in FIG. 21 , the bulging portion 30 is a portion that bulges inward in the radial direction y of the first tubular portion 10 by expanding.

[0172] 18 to 21, the flow path 40 has a space into which the fluid can be injected up to the bag-shaped body portion 20 and a space into which the fluid can be injected up to the bulging portion 30. The space into which the fluid can be injected up to the bag-shaped body portion 20 and the space into which the fluid can be injected up to the bulging portion 30 may be connected to each other, or may be separate spaces that are not connected to each other.

[0173] The inner cavity of the first shaft 1 is preferably configured by the inner cavity 11 of the first tubular portion 10 and the inner cavity 25 of the bag-like body portion 20 communicating with each other.

[0174] The second shaft 2 includes a second cylindrical portion 50 and an expanded / contracted diameter portion 60 , and is disposed in the inner cavity of the first shaft 1 .

[0175] The second cylindrical portion 50 preferably extends in the longitudinal direction of the first shaft 1. The second cylindrical portion 50 preferably has an inner cavity extending in the longitudinal direction of the first shaft 1.

[0176] The expandable / contractable section 60 is a section that can expand and contract in diameter, and is fixed to the distal part of the second tubular section 50 .

[0177] 21 , a first portion 61, which is a part of the expandable / contractable section 60, is located in the lumen of the first shaft 1, and a second portion 62, which is a portion of the expandable / contractable section 60 located distal to the first portion 61, is located outside the first shaft 1. Furthermore, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular section 10, and the outer surface of the first portion 61 is inscribed in the first shaft 1. With the above configuration, the length of the expandable / contractable section 60 that contacts the treatment area can be easily adjusted to a desired length.

[0178] 21 , the bulging portion 30 of the catheter 100 bulges inward in the radial direction y of the first tubular portion 10. This makes it easier to suppress movement of the second shaft 2 in the longitudinal direction of the first shaft 1.

[0179] 21 when pressurized by injection of fluid into the flow path 40, the bulging portion 30 bulges inward in the radial direction y of the first cylindrical portion 10. This causes the bulging portion 30 to bulge when pressurized.

[0180] 18 and 20 , when the diameter-expanding section 60 is not disposed in the lumen 25 at the distal end of the bag-shaped body section 20, the minimum inner diameter of the bag-shaped body section 20 when the bag-shaped body section 20 is pressurized by injecting fluid into the flow path 40 is configured to be larger than the minimum inner diameter of the bag-shaped body section 20 when no pressurization is performed by injecting fluid into the flow path 40. This increases the minimum inner diameter of the bag-shaped body section 20 when it is pressurized.

[0181] The catheter 100 can be used, for example, by inserting the distal end of the first shaft 1 to a treatment site, and then protruding a portion of the expandable / contractable section 60 disposed in the lumen of the first shaft 1 from the first shaft 1. When transporting the first shaft 1 to the treatment site, as shown in FIG. 18 , the first shaft 1 is not pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-like body portion 20 is smaller than the minimum inner diameter of the bag-like body portion 20 when the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40, making it easier to reduce the outer diameter of the bag-like body portion 20. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. After transporting the first shaft 1 to the treatment site, as shown in FIG. 20 , the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-shaped body portion 20 is larger than the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injection of fluid into the flow path 40 is not performed. This makes it easier to protrude a portion of the expandable / contractable portion 60, which is disposed in the lumen of the first shaft 1, from the expanded-diameter bag-shaped body portion 20. After the bag-shaped body portion 20 is pressurized by injection of fluid into the flow path 40, as shown in FIG. 21 , the first portion 61 is located in the lumen of the first shaft 1, the second portion 62 is located outside the first shaft 1, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular portion 10, the outer surface of the first portion 61 is inscribed in the first shaft 1, and the bulging portion 30 bulges inward in the radial direction y of the first tubular portion 10. This makes it easier to adjust the length of the expandable / contractable portion 60 that contacts the treatment site to a desired length. Furthermore, the bulging portion 30 bulges inward in the radial direction y of the first tubular portion 10, which makes it easier for the bulging portion 30 to come into contact with the second shaft 2. This makes it easier to suppress movement of the second shaft 2 in the longitudinal direction of the first shaft 1.

[0182] The first cylindrical portion 10 preferably has a distal end 10 a and a proximal end 10 b. The first cylindrical portion 10 also preferably has an inner surface 10 c facing the lumen 11 of the first cylindrical portion 10 and an outer surface 10 d facing the outside of the first cylindrical portion 10.

[0183] The outer surface 10d of the first cylindrical portion 10 is preferably coated with a hydrophilic polymer, which makes it easier to insert the first cylindrical portion 10 into a body cavity. Examples of hydrophilic polymers include poly (2-hydroxyethyl methacrylate), polyacrylamide, polyvinylpyrrolidone, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers, and polyethylene glycol.

[0184] The inner surface 10c of the first tubular portion 10 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin, or the entire inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin. This makes the first tubular portion 10 more easily slippery relative to components placed in the lumen 11 of the first tubular portion 10, thereby making it easier to improve the operability of the catheter 100.

[0185] As shown in Figure 23, the first tubular portion 10 has a distal opening 11a at a distal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10, and may have a proximal opening 11b at a proximal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10.

[0186] As shown in Figures 22 and 23, the first tubular portion 10 can be configured to have a tapered region 13 in the proximal portion of the first tubular portion 10, in which the length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x of the first tubular portion 10 decreases toward the proximal side.

[0187] 23 , it is preferable that a proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in the tapered region 13. It is more preferable that the proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in a portion that slopes so that the length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x decreases toward the proximal side. With this configuration, for example, the guidewire 4 or the second shaft 2 can be inserted into and removed from the lumen 11 of the first tubular portion 10 through the proximal opening 11b.

[0188] 22 and 23 , the first shaft 1 may further include a third tubular portion 70. A distal portion of the third tubular portion 70 is fixed to a proximal portion of the reduced diameter region 13, and a lumen 71 of the third tubular portion 70 and the flow path 40 can be configured to communicate with each other.

[0189] The third cylindrical portion 70 is a cylindrical portion having an inner cavity 71. It is preferable that the maximum outer diameter of the third cylindrical portion 70 is smaller than the maximum outer diameter of the first cylindrical portion 10. Furthermore, the minimum outer diameter of the third cylindrical portion 70 may be smaller than the minimum outer diameter of the first cylindrical portion 10.

[0190] For the configuration of the third cylindrical portion 70, such as the material constituting the third cylindrical portion 70, reference can be made to the description of the first cylindrical portion 10. The material constituting the third cylindrical portion 70 and the material constituting the first cylindrical portion 10 may be the same or different.

[0191] It is preferable that a lubricating coating layer containing PTFE, PFA, or the like is formed on the outer surface of the third cylindrical portion 70. This makes it easier to insert the third cylindrical portion 70 into a body cavity.

[0192] The third cylindrical portion 70 may be provided with a position indication marker for indicating the length of the inserted portion when the first shaft 1 is inserted into a body cavity. The position indication marker may be formed, for example, by inserting the third cylindrical portion 70 into the inner cavity of a marker tube and welding it, or may be formed by peeling off a part of the lubricating coating layer containing the above-mentioned PTFE, PFA, or the like.

[0193] The position indication markers can be provided, for example, at positions 600 mm, 900 mm, 1200 mm, etc. from the distal end of the first shaft 1.

[0194] It is preferable that the distal portion of the third tubular portion 70 and the proximal portion of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is more preferable that the distal end of the third tubular portion 70 and the proximal end of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is preferable that the lumen 71 of the third tubular portion 70 does not communicate with the lumen 11 of the first tubular portion 10.

[0195] 22 , the catheter 100 preferably further includes a hub 72 connected to the proximal end of the first shaft 1. The hub 72 may be connected to the third cylindrical portion 70. In this case, the hub 72 preferably includes a port therein that communicates with the lumen 71 of the third cylindrical portion 70, and a fluid can be injected into the lumen 71 of the third cylindrical portion 70 via the port.

[0196] Although not shown, the first shaft 1 may not include the third cylindrical portion 70, and the proximal end 10b of the first cylindrical portion 10 may be directly connected to the hub 72. In this case, it is preferable that the hub 72 has a port therein that communicates with the flow path 40, and that a fluid can be injected into the flow path 40 via the port.

[0197] The material constituting the bag-shaped body portion 20 can be, for example, any of the materials listed as being constituting the first tubular portion 10. The material constituting the bag-shaped body portion 20 and the material constituting the first tubular portion 10 may be the same or different.

[0198] As shown in Figures 22 and 23, the proximal portion of the bag-shaped body portion 20 may be connected to the distal portion of the first tubular portion 10, or the proximal end of the bag-shaped body portion 20 may be connected to the distal end 10a of the first tubular portion 10.

[0199] The minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. In particular, as shown in FIG. 25 , when pressurization by injecting a fluid into the flow path 40 is not performed, the minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. This makes it less likely that the first shaft 1 will get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. From the viewpoint of enhancing this effect, as shown in FIG. 25 , when pressurization by injecting a fluid into the flow path 40 is not performed, the maximum outer diameter of the bag-shaped body portion 20 is more preferably equal to or smaller than the outer diameter of the first tubular portion 10. Note that, as shown in FIGS. 26 and 27 , even when the bag-shaped body portion 20 is pressurized by injecting a fluid into the flow path 40, the minimum outer diameter of the bag-shaped body portion 20 may be smaller than the outer diameter of the first tubular portion 10. As shown in Figure 21, when the expansion / contraction diameter portion 60 is placed in the inner cavity 25 of the bag-shaped body portion 20 and the expansion / contraction diameter portion 60 expands, the maximum outer diameter of the bag-shaped body portion 20 may be greater than or equal to the outer diameter of the first tubular portion 10.

[0200] The bag-shaped body portion 20 provided distal to the distal end 10a of the first tubular portion 10 preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 25 , when pressurization by injecting a fluid into the flow path 40 is not performed, the bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 25 , when pressurization by injecting a fluid into the flow path 40 is not performed, the entire bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. Note that, as shown in FIGS. 26 and 27 , when pressurization by injecting a fluid into the flow path 40 is performed, the bag-shaped body portion 20 may have a tapered portion whose outer diameter decreases toward the distal side. 26 and 27 , the entire bag-shaped body portion 20 may be a tapered portion whose outer diameter decreases toward the distal side when the bag-shaped body portion 20 is pressurized by injection of a fluid into the flow path 40. As shown in Fig. 21 , when the expandable / contractable diameter portion 60 is disposed in the lumen 25 of the bag-shaped body portion 20 and the expandable / contractable diameter portion 60 expands in diameter, the bag-shaped body portion 20 may have a tapered portion whose outer diameter decreases toward the proximal side, or the entire bag-shaped body portion 20 may be a tapered portion whose outer diameter decreases toward the proximal side.

[0201] The bag-shaped body portion 20 is formed in an annular shape, but may also have a hollow truncated cone shape, for example, as shown in Figures 22 to 24. Although not shown, the bag-shaped body portion 20 may also have a hollow truncated polygonal pyramid shape, or a shape that combines a hollow truncated cone and a hollow truncated polygonal pyramid, for example, a shape in which a hollow truncated cone and a hollow truncated polygonal pyramid are connected in the longitudinal direction x of the first tubular portion 10.

[0202] The bulging portion 30 preferably bulges inward in the radial direction y of the first tubular portion 10 when the fluid is injected into the flow path 40 and the pressure therein is equal to or greater than a first predetermined pressure. This allows the bulging portion 30 to bulge when the pressure therein is equal to or greater than the first predetermined pressure. Furthermore, when the expandable / contractable portion 60 is not disposed in the lumen 25 at the distal end of the bag-like body portion 20, the minimum inner diameter of the bag-like body portion 20 when the fluid is injected into the flow path 40 and the pressure therein is equal to or greater than a second predetermined pressure is preferably larger than the minimum inner diameter of the bag-like body portion 20 when the fluid is not injected into the flow path 40 and the pressure therein is equal to or greater than the second predetermined pressure. This allows the minimum inner diameter of the bag-like body portion 20 to increase when the pressure therein is equal to or greater than the second predetermined pressure.

[0203] The first predetermined pressure and the second predetermined pressure may be the same value or may be different values.

[0204] For example, if the space into which fluid can be injected up to the bulging portion 30 and the space into which fluid can be injected up to the bag-shaped body portion 20 are separate spaces that do not communicate with each other, it is possible to adjust the timing of inflating the bulging portion 30 and the timing of expanding the diameter of the bag-shaped body portion 20 by adjusting the order in which fluid is injected into each space. This allows the bulging portion 30 to be inflated after the diameter of the bag-shaped body portion 20 is expanded. More specifically, when fluid is injected into a space into which fluid can be injected into the bag-shaped body portion 20 but not into the bulging portion 30, the bag-shaped body portion 20 is pressurized, thereby increasing the minimum inner diameter of the bag-shaped body portion 20. When fluid is injected into a space into which fluid can be injected into the bulging portion 30 but not into the bag-shaped body portion 20, the bulging portion 30 is pressurized, thereby inflating the bulging portion 30.

[0205] Furthermore, when the space into which fluid can be injected up to the bulging portion 30 and the space into which fluid can be injected up to the bag-shaped body portion 20 are connected, or when the space into which fluid can be injected up to the bulging portion 30 and the space into which fluid can be injected up to the bag-shaped body portion 20 partially overlap, it is preferable that the second predetermined pressure be lower than the first predetermined pressure. This allows the bulging portion 30 to bulge after the diameter of the bag-shaped body portion 20 is expanded. More specifically, in the first shaft 1 shown in FIG. 25 in a state where pressurization by injecting fluid into the flow path 40 is not performed, the bag-shaped body portion 20 is pressurized at or above the second predetermined pressure by injecting fluid into the flow path 40, so that the minimum inner diameter of the bag-shaped body portion 20 increases as shown in FIG. 26 , and when fluid is injected into the flow path 40, the bulging portion 30 is pressurized at or above the first predetermined pressure that is higher than the second predetermined pressure, so that the bulging portion 30 bulges as shown in FIG. 27 .

[0206] 23 to 27, the bag-shaped body portion 20 can be configured to have an inner surface portion 21 facing the lumen 25 of the bag-shaped body portion 20, and an outer surface portion 22 facing the exterior of the bag-shaped body portion 20. The inner surface portion 21 has an inner surface facing the lumen 25, and the outer surface portion 22 has an outer surface facing the exterior. The inner surface portion 21 has a distal end 21a and a proximal end 21b. The outer surface portion 22 has a distal end 22a and a proximal end 22b. It is preferable that an internal space 23 exists between the inner surface portion 21 and the outer surface portion 22.

[0207] It is preferable that the elongation percentage (%) of the length from the distal end 21 a to the proximal end 21 b of the inner surface portion 21 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized at or above the second predetermined pressure by injecting a fluid into the flow path 40 is greater than the elongation percentage (%) of the length from the distal end 22 a to the proximal end 22 b of the outer surface portion 22 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized at or above the second predetermined pressure by injecting a fluid into the flow path 40. With the above-described configuration, when the bag-shaped body portion 20 is pressurized to or above the second predetermined pressure by injecting a fluid, the inner surface portion 21, which is more elongate than the outer surface portion 22, stretches, and the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. This allows the minimum inner diameter of the bag-shaped body portion 20 when it is pressurized to a pressure equal to or greater than the second predetermined pressure by injecting a fluid into the flow path 40 to be larger than the minimum inner diameter of the bag-shaped body portion 20 when it is not pressurized by injecting a fluid into the flow path 40. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 25 to the state shown in FIG. 26. Therefore, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site, it is possible to make the second shaft 2 more likely to protrude from the expanded diameter portion. The elongation rate (%) is calculated by dividing the length of each portion after pressurization by the length of each portion before pressurization.

[0208] The inner surface portion 21 and the outer surface portion 22 may be made of the same material or different materials.

[0209] When the inner surface portion 21 and the outer surface portion 22 are made of the same material, for example, it is preferable that the thickness of the inner surface portion 21 is thinner than the thickness of the outer surface portion 22. This makes the inner surface portion 21 more stretchable than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in Fig. 25 to the state shown in Fig. 26. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0210] When the inner surface portion 21 and the outer surface portion 22 are made of different materials, for example, it is preferable that the elongation rate of the material making up the inner surface portion 21 be higher than that of the material making up the outer surface portion 22. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material making up the inner surface portion 21 and a sample made of the material making up the outer surface portion 22, formed to the same shape as the sample, are prepared, and then the samples are gripped at one end and the other end so that the grip width is the same length and pulled with the same strength (N). This makes the inner surface portion 21 more elongate than the outer surface portion 22, and the inner diameter of the bag-shaped body portion 20 is likely to increase as a result of the elongation of the inner surface portion 21 of the bag-shaped body portion 20. In the example described above, the first shaft 1 is likely to change from the state shown in FIG. 25 to the state shown in FIG. 26. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0211] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, the angle α between the inner surface portion 21 and the outer surface portion 22 when pressurization by injecting a fluid into the flow path 40 is not performed is preferably an acute angle, as shown in FIG. 25 . The angle α may be 85° or less, 80° or less, or 70° or less. The angle α may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity.

[0212] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, when the first tubular portion 10 is pressurized to a second predetermined pressure or higher by the injection of a fluid into the flow path 40, the angle δ between the inner surface portion 21 and the outer surface portion 22 is preferably an acute angle, as shown in FIG. 26 . The angle δ may be 85° or less, 80° or less, or 70° or less. The angle δ may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the thickness of the distal end of the bag-shaped body portion 20. In other words, it makes it easier to shorten the length between the inner surface of the inner surface portion 21 and the outer surface of the outer surface portion 22. Therefore, it makes it easier to increase the inner diameter of the distal end of the bag-shaped body portion 20 when the first tubular portion 10 is pressurized to a second predetermined pressure or higher by the inflow of a fluid into the flow path 40. Therefore, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to a treatment site, it makes it easier to protrude the second shaft 2 from the expanded diameter portion.

[0213] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, when the first tubular portion 10 is pressurized to a first predetermined pressure or higher by injecting a fluid into the flow path 40, the angle γ between the inner surface portion 21 and the outer surface portion 22 is preferably an acute angle, as shown in FIG. 27 . The angle γ may be 85° or less, 80° or less, or 70° or less. The angle γ may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the thickness of the distal end portion of the bag-shaped body portion 20. In other words, it makes it easier to shorten the length between the inner surface of the inner surface portion 21 and the outer surface of the outer surface portion 22.

[0214] As shown in Figures 23 and 24 , the internal space 23 is a space formed within the wall that constitutes the annular bag-shaped body portion 20. In the example shown in Figures 23 and 24 , the internal space 23 is a space that exists within the wall that forms the lumen 25 of the bag-shaped body portion 20. As shown in Figures 23 and 24 , the internal space 23 preferably exists throughout the entire circumferential direction within the wall of the bag-shaped body portion 20. In other words, the internal space 23 is preferably a space that is circumferentially connected within the wall of the bag-shaped body portion 20. Although not shown, the internal space 23 may exist only partially within the circumferential direction within the wall of the bag-shaped body portion 20.

[0215] It is preferable that the internal space 23 does not communicate with the lumen 11 of the first tubular portion 10. It is also preferable that the internal space 23 does not communicate with the lumen 25 of the bag-shaped body portion 20. This makes it easier for the fluid injected into the flow path 40 to efficiently flow into the internal space 23 formed in the bag-shaped body portion 20.

[0216] 25 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when pressurization by injecting a fluid into the flow path 40 is not being performed, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0217] 26 , when the bag-shaped body portion 20 is pressurized to a second predetermined pressure or higher by injection of a fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, when the minimum internal diameter of the bag-shaped body portion 20 increases as a result of pressurization of the bag-shaped body portion 20 to a second predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0218] 25 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when pressurization by injection of a fluid into the flow path 40 is not being performed, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0219] 26 , when the bag-shaped body portion 20 is pressurized to a second predetermined pressure or higher by the injection of fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, when the minimum inner diameter of the bag-shaped body portion 20 increases as a result of the bag-shaped body portion 20 being pressurized to a second predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0220] The length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when no pressurization is performed by injecting a fluid into the flow path 40 and the length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when the bag-shaped body portion 20 is pressurized to a second predetermined pressure or higher by injecting a fluid into the flow path 40 may be the same or different.

[0221] The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0222] The length of the bag-shaped body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-shaped body portion 20 is pressurized to the second predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-shaped body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-shaped body portion 20 is pressurized to the second predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0223] The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed is preferably a size that allows the guide wire 4 to be inserted therethrough. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 30% or more, 35% or more, or 40% or more of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 70% or less, 65% or less, or 60% or less of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc. Furthermore, the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 2.00 mm or less, 1.95 mm or less, 1.90 mm or less, etc.

[0224] 25 , in a state where no pressurization is performed by injecting a fluid into the flow path 40, the inner diameter of the bag-shaped body portion 20 is preferably smallest at the distal end of the bag-shaped body portion 20. In a state where pressurization is performed to a pressure equal to or greater than the second predetermined pressure or the first predetermined pressure by injecting a fluid into the flow path 40, the inner diameter of the bag-shaped body portion 20 may be smallest at the proximal end or the distal end of the bag-shaped body portion 20.

[0225] The minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 0.31 mm or more, 0.36 mm or more, 0.41 mm or more, etc. Furthermore, the minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 3.00 mm or less, 2.90 mm or less, 2.80 mm or less, etc.

[0226] As shown in Fig. 25 , in a state where pressurization by injection of a fluid into the flow path 40 is not performed, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter. As shown in Fig. 26 , in a state where pressurization to a second predetermined pressure or higher by injection of a fluid into the flow path 40 is performed, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter. As shown in Fig. 27 , in a state where pressurization to a first predetermined pressure or higher by injection of a fluid into the flow path 40 is performed, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter.

[0227] The materials constituting the bulging portion 30 may be the same as or different from the materials constituting the first tubular portion 10 or the materials constituting the balloon.

[0228] 27 to 30 , the bulging portion 30 may be a portion that bulges inward in the radial direction y of the first tubular portion 10 by expanding a portion of the first tubular portion 10. Although not shown, the bulging portion 30 may have a configuration separate from the first tubular portion 10. For example, the bulging portion 30 may be a bag-shaped member disposed in the lumen 11 of the first tubular portion 10, and the fluid may be injected through a tubular member connected to the bag-shaped member. In this case, the lumen of the tubular member functions as the flow path 40.

[0229] As shown in Figure 27, when the bulging portion 30 is a portion that bulges inward in the radial direction y of the first tubular portion 10 due to the expansion of a portion of the first tubular portion 10, it is preferable that the portion of the first tubular portion 10 that constitutes the bulging portion 30 is thinner than the portion of the first tubular portion 10 other than the bulging portion 30. This makes the portion of the first tubular portion 10 that constitutes the bulging portion 30 more easily stretchable than the portion of the first tubular portion 10 other than the bulging portion 30, making it easier to bulge the portion of the first tubular portion 10 that constitutes the bulging portion 30. In the example described above, the first shaft 1 is more likely to change from the state shown in Figure 26 to the state shown in Figure 27.

[0230] As shown in FIG. 27 , when the bulging portion 30 is a portion of the first tubular portion 10 that bulges inward in the radial direction y due to expansion of a portion of the first tubular portion 10, it is preferable that the elongation rate of the material constituting the bulging portion 30 of the first tubular portion 10 be higher than the elongation rate of the material constituting the remaining portion of the first tubular portion 10. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material constituting the bulging portion 30 of the first tubular portion 10 and a sample formed to the same shape as the sample made of the material constituting the remaining portion of the first tubular portion 10 other than the bulging portion 30 are prepared, and one end of each sample is gripped to the same length and the other end is pulled with the same strength (N). This makes the bulging portion 30 more elongate than the remaining portion of the first tubular portion 10, making the bulging portion 30 more likely to bulge when pressurized. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 26 to the state shown in FIG. 27 .

[0231] The bulge portion 30 may be present in a portion of the circumference of the first tubular portion 10 as shown in Figures 28 and 29, or may be present in the entire circumference of the first tubular portion 10 as shown in Figure 30.

[0232] The first shaft 1 may have only one bulging portion 30 or may have a plurality of bulging portions 30 .

[0233] 29 , when the second shaft 2 is not positioned distal to the proximal end of the bulging portion 30 and is pressurized to a first predetermined pressure or higher by injecting a fluid into the flow path 40, it is preferable that a first surface portion 31, which is a part of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y, abuts against a second surface portion 32, which is a part of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y and is different from the first surface portion 31. For example, as shown in FIG. 18 , when the second shaft 2 and the guidewire 4 are disposed in the lumen of the first shaft 1 and used, the second shaft 2 can be moved proximal to the proximal end of the bulging portion 30 in the lumen of the first shaft 1 and then the bulging portion 30 is bulged, thereby sandwiching the guidewire 4 between the first surface portion 31 and the second surface portion 32 of the bulging portion 30. This makes it possible to easily suppress movement of the guide wire 4 in the longitudinal direction x of the first tubular portion 10. Therefore, it is possible to easily remove the second shaft 2 without removing the guide wire 4 from the lumen of the first shaft 1.

[0234] As shown in Figure 30 , when the second shaft 2 is not positioned distal to the proximal end of the bulging portion 30 and is pressurized to a pressure equal to or greater than the first predetermined pressure by injecting a fluid into the flow path 40, the lumen 11 of the first tubular portion 10 is preferably blocked by the bulging portion 30. For example, as shown in Figure 18 , when the second shaft 2 and the guidewire 4 are positioned in the lumen of the first shaft 1 and used, the second shaft 2 can be moved proximal to the proximal end of the bulging portion 30 in the lumen of the first shaft 1 and then the bulging portion 30 can be bulged to block the lumen 11, thereby allowing the bulging portion 30 to grip the guidewire 4. This makes it easier to suppress movement of the guidewire 4 in the longitudinal direction x of the first tubular portion 10. This makes it easier to remove the second shaft 2 without removing the guidewire 4 from the lumen of the first shaft 1.

[0235] The frictional force of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y is preferably higher than the frictional force of the inner surface 10c of the first tubular portion 10 facing the lumen 11 of the first tubular portion 10. It is more preferable that the frictional force of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y when the first tubular portion 10 is pressurized by injecting a fluid into the flow path 40 is higher than the frictional force of the inner surface 10c of the first tubular portion 10 facing the lumen 11 of the first tubular portion 10 when the first tubular portion 10 is pressurized by injecting a fluid into the flow path 40. The frictional force of each surface can be adjusted by changing the coating, surface roughness, material, etc. This configuration makes it easier to suppress movement of the second shaft 2 and the guide wire 4 placed in the lumen of the first shaft 1 in the longitudinal direction x of the first tubular portion 10. 27 , when the bulging portion 30 is a portion that bulges inward in the radial direction y of the first tubular portion 10 due to the bulging of a portion of the first tubular portion 10, the frictional force of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y is preferably higher than the frictional force of the inner surface 10c of the first tubular portion 10 facing the lumen 11 of the first tubular portion 10, which constitutes the first tubular portion 10 other than the bulging portion 30. It is more preferable that the frictional force of the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y when the first tubular portion 10 is pressurized by the injection of fluid into the flow path 40 is higher than the frictional force of the inner surface 10c of the first tubular portion 10 facing the lumen 11 of the first tubular portion 10, which constitutes the first tubular portion 10 other than the bulging portion 30 when the first tubular portion 10 is pressurized by the injection of fluid into the flow path 40.

[0236] 27 , the bulging portion 30 is preferably located more proximal than the proximal end of the bag-shaped body portion 20. Alternatively, the bulging portion 30 may be located more proximal than the distal end 10 a of the first tubular portion 10. The bulging portion 30 is preferably provided in the distal portion of the first tubular portion 10.

[0237] 18 to 21, 25 to 27, and 31 to 33, the first tubular portion 10 can have a wall 12 that forms the lumen 11, and the flow path 40 can be formed within the wall 12 of the first tubular portion 10. This configuration eliminates the need to provide a separate member for forming the flow path 40, making it easier to make the catheter 100 thinner.

[0238] 25 and 31 , the first tubular portion 10 may have a first outer cylinder 15 and a first inner cylinder 14 disposed in the lumen of the first outer cylinder 15, and the flow path 40 may be a space defined by an inner surface 15c of the first outer cylinder 15 and an outer surface 14d of the first inner cylinder 14. This configuration eliminates the need to provide a separate member for forming the flow path 40, making it easier to make the catheter 100 thinner.

[0239] 31 , the distance between the inner surface 15c of the first outer cylinder 15 and the outer surface 14d of the first inner cylinder 14 is preferably 0.01 mm or more and 1.0 mm or less, which can reduce pressure loss when delivering fluid to the distal end through the flow path 40.

[0240] The first outer cylinder 15 may have a distal end and a proximal end, and may have a lumen extending in the longitudinal direction x. The same applies to the first inner cylinder 14.

[0241] When the bag-shaped body portion 20 changes from a state in which it is not pressurized by injecting a fluid into the flow path 40 to a state in which it is pressurized at or above the second predetermined pressure by injecting a fluid into the flow path 40, the elongation percentage (%) of the length from the distal end 21a to the proximal end 21b of the inner surface portion 21 is preferably greater than the elongation percentage (%) of the length from the distal end 10a to the proximal end 10b of the first tubular portion 10. This configuration is particularly preferable when the flow path 40 is formed within the wall 12 of the first tubular portion 10. The higher elongation percentage (%) of the bag-shaped body portion 20 than that of the first tubular portion 10 makes it possible to make the first tubular portion 10 less susceptible to deformation by fluid pressure, thereby facilitating the stable supply of fluid injected into the flow path 40 to the bag-shaped body portion 20.

[0242] 32 and 33 , the flow path 40 may extend linearly in the longitudinal direction x of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10. Although not shown, the flow path 40 may be formed in a wave shape within the wall 12 of the first cylindrical portion 10, or the flow path 40 may be formed in a spiral shape that circles around the inner cavity 11 of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10.

[0243] 32 and 33 , when the flow path 40 extends linearly in the longitudinal direction x of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10, it is preferable that the internal space 23 that is continuous throughout the entire circumferential direction of the first cylindrical portion 10 within the wall of the bag-shaped body portion 20 communicates with the linear flow path 40. This allows the fluid injected into the flow path 40 to be injected into the internal space 23 of the bag-shaped body portion 20.

[0244] The flow path 40 may be formed not only within the wall 12 of the first cylindrical portion 10, but also by providing a component separate from the first cylindrical portion 10. For example, as shown in FIGS. 34 and 35 , the flow path 40 may be formed by a fourth cylindrical portion 41 disposed in the lumen 11 of the first cylindrical portion 10. The fourth cylindrical portion 41 is a cylindrical portion having a lumen, and the lumen of the fourth cylindrical portion 41 is the flow path 40. By disposing the fourth cylindrical portion 41 in the lumen 11 of the first cylindrical portion 10, the catheter 100 can be made thinner. Although not shown, the fourth cylindrical portion 41 may also be disposed outside the first cylindrical portion 10.

[0245] When the flow path 40 is formed by the fourth cylindrical portion 41, it is preferable that the distal end portions of the bag-shaped body portion 20 and the fourth cylindrical portion 41 are fixed together, as shown in Figures 34 and 35. It is also preferable that the bag-shaped body portion 20 has a hole 24 that connects the flow path 40 with the internal space 23. This allows the fluid injected into the flow path 40 formed by the fourth cylindrical portion 41 to be injected into the internal space 23 of the bag-shaped body portion 20.

[0246] For the configuration of the fourth cylindrical portion 41, such as the material constituting the fourth cylindrical portion 41, reference can be made to the portion described for the first cylindrical portion 10. The material constituting the first cylindrical portion 10, the material constituting the third cylindrical portion 70, and the material constituting the fourth cylindrical portion 41 may be the same or different.

[0247] The space into which the fluid can be injected up to the bulging portion 30 and the space into which the fluid can be injected up to the bag-shaped body portion 20 may be connected. Also, the space into which the fluid can be injected up to the bulging portion 30 and the space into which the fluid can be injected up to the bag-shaped body portion 20 may partially overlap.

[0248] The fluid to be introduced into the flow channel 40 is not particularly limited, but may be, for example, a liquid such as physiological saline, a contrast medium, or a mixture thereof, or a gas such as air, nitrogen, or carbon dioxide.

[0249] The fluid injected up to the bag-shaped body portion 20 may pass through a space through which the fluid can be injected up to the bulging portion 30. The fluid injected up to the bulging portion 30 may pass through a space through which the fluid can be injected up to the bag-shaped body portion 20.

[0250] The fluid is preferably radiopaque. By injecting a radiopaque fluid, the distal end of the bag-shaped body portion 20 can be more easily visualized, and therefore the proximal end of the expandable diameter portion 60 that contacts the treatment site can be more easily visualized.

[0251] 18 and 19 , a reinforcing member 16 may be disposed between the flow path 40 and the lumen 11 of the first tubular portion 10. This makes it possible to more easily prevent the flow path 40 from collapsing even when a member that expands in diameter is disposed in the lumen of the first shaft 1.

[0252] The reinforcing member 16 may be made of metal. The reinforcing member 16 may be made of resin. As the metal or resin constituting the reinforcing member 16, the materials listed as the materials constituting the first tubular portion 10 can be used.

[0253] The reinforcing member 16 is preferably configured by a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof. The wire may be a solid wire or a twisted wire.

[0254] 36 , in a state where pressurization by injection of a fluid into the flow path 40 is not performed, the first tubular portion 10 may have a protrusion 17 that protrudes inward in the radial direction y of the first tubular portion 10. In other words, the protrusion 17 is a portion that protrudes inward in the radial direction y of the first tubular portion 10 regardless of whether or not a fluid is injected into the flow path 40. This makes it easier to suppress movement of a member disposed in the lumen of the first shaft 1 in the longitudinal direction x of the first tubular portion 10.

[0255] The protruding height 17L of the protruding portion 17 and the protruding height 30L of the bulging portion 30 may be the same or different. The protruding height 17L of the protruding portion 17 may be higher than the protruding height 30L of the bulging portion 30. The protruding height 17L of the protruding portion 17 may be lower than the protruding height 30L of the bulging portion 30. The protruding height 17L of the protruding portion 17 refers to the length of the protruding portion in the radial direction y of the first cylindrical portion 10. The protruding height 30L of the bulging portion 30 refers to the length of the bulging portion in the radial direction y of the first cylindrical portion 10.

[0256] A radiopaque portion 3 may be provided in at least one of the sac-shaped body portion 20 and a region extending 10 cm proximally from the distal end 10a of the first tubular portion 10. This configuration makes it possible to visually confirm the position of the distal end of the catheter 100 using an X-ray imaging device. Figures 34 and 35 show an embodiment in which the radiopaque portion 3 is provided in the first tubular portion 10, while Figures 18 to 21 show an embodiment in which the radiopaque portion 3 is provided in the sac-shaped body portion 20.

[0257] The radiopaque portion 3 may be provided only in the bag-shaped body portion 20. The radiopaque portion 3 may be provided only in a region from the distal end 10a of the first cylindrical portion 10 to a position 10 cm proximal to the bag-shaped body portion 20. The radiopaque portion 3 may be provided both in the bag-shaped body portion 20 and in a region from the distal end 10a of the first cylindrical portion 10 to a position 10 cm proximal to the bag-shaped body portion 20.

[0258] 21, it is preferable that an X-ray opaque portion 3 is provided at the distal end of the bag-shaped body portion 20. This makes it easier to visualize the proximal end of the expandable / contractable portion 60 that contacts the treatment site.

[0259] The shape of the radiopaque portion 3 is preferably tubular, and examples thereof include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross section with a notch in the tube, and a coil shape with a wound wire.

[0260] The material constituting the radiopaque portion 3 may be, for example, a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt-chromium alloy, and may be a form in which radiopaque particles such as barium sulfate are dispersed in the first tubular portion 10, the bag-shaped body portion 20, or a separately provided resin member.

[0261] The second cylindrical portion 50 may have a lumen extending in the longitudinal direction of the first shaft 1. The lumen of the second cylindrical portion 50 may be used as a passage for inserting a guide wire 4 or the like, as shown in Figures 18 to 21 .

[0262] As shown in Figures 18 to 21, the second tubular portion 50 may be configured to include a second outer tube 52 arranged in the inner cavity 11 of the first tubular portion 10, and a second inner tube 51 arranged in the inner cavity of the second outer tube 52.

[0263] For the configuration of the second cylindrical portion 50, such as the material constituting the second cylindrical portion 50, reference can be made to the portion described for the first cylindrical portion 10. The material constituting the first cylindrical portion 10, the material constituting the third cylindrical portion 70, the material constituting the fourth cylindrical portion 41, and the material constituting the second cylindrical portion 50 may be the same or different. Note that the material constituting the second inner cylinder 51 and the material constituting the second outer cylinder 52 may be the same or different.

[0264] The inner surface of the second inner tube 51 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface of the second inner tube 51 may be made of a fluororesin or a polyolefin resin, or the entire inner surface of the second inner tube 51 may be made of a fluororesin or a polyolefin resin. This allows the second inner tube 51 to slide easily over the guidewire 4, thereby making it easier to improve the operability of the catheter 100.

[0265] A control mechanism that suppresses movement of the second shaft 2 in the longitudinal direction x of the first tubular portion 10 may be provided in the proximal portion of the catheter 100. With this configuration, the control mechanism makes it possible to transport the catheter 100 to the treatment site while suppressing movement of the second shaft 2 in the longitudinal direction x of the first tubular portion 10, thereby making it easier to transport the catheter 100 to the treatment site.

[0266] Although not shown, one example of the control mechanism is a mode in which the third tubular portion 70 is provided with a gripping member capable of gripping the second tubular portion 50. By gripping the second tubular portion 50 with the gripping member, it is possible to temporarily suppress movement of the second tubular portion 50 in the longitudinal direction x of the first tubular portion 10. Then, by detaching the second tubular portion 50 from the gripping member, it is possible to return the second tubular portion 50 to a state in which it is movable relative to the first shaft 1. Examples of the gripping member include a rubber member provided with a slit that grips the second tubular portion 50 by pinching it, and a clip made of rigid resin.

[0267] The expandable / contractable section 60 may be, for example, a balloon or a stent that can expand and contract in diameter.

[0268] 18, 20, and 21, when the second tubular portion 50 has a second inner cylinder 51 and a second outer cylinder 52, and the expandable / contractable portion 60 is a balloon, it is preferable that the distal end of the expandable / contractable portion 60 is fixed to the distal portion of the second inner cylinder 51, and the proximal end of the expandable / contractable portion 60 is fixed to the distal portion of the second outer cylinder 52. The expandable / contractable portion 60 can be expanded by injecting a fluid into the space surrounded by the second inner cylinder 51 and the second outer cylinder 52.

[0269] A stent is a tubular structure that can expand and contract in diameter, for example, composed of a mesh or other network structure. It is preferable that the stent expands and contracts, for example, in its circumferential and axial directions. Examples of stents include a coil-shaped stent made of a single linear metal or polymeric material, a metal tube or a polymeric tube cut out with a laser or the like, a stent assembled by welding linear members, and a stent made by weaving multiple linear metal members.

[0270] The stent may be a self-expanding stent or a balloon-expandable stent.

[0271] The expandable / contractable section 60 preferably uses a balloon or stent having a coating layer formed on its outer surface 63. After the catheter 100 reaches the treatment site, fluid is injected into the flow path 40 to pressurize the sac-shaped body portion 20, increasing the minimum inner diameter of the sac-shaped body portion 20 compared to before pressurization. In the example described above, the catheter 100 changes from the state shown in FIG. 18 to the state shown in FIG. 20 by injecting fluid. After the balloon or stent placed in the lumen of the first shaft 1 in the state shown in FIG. 18 is transported to the treatment site, the minimum lumen of the sac-shaped body portion 20 is enlarged as shown in FIG. 20. This makes it easier to protrude a portion of the second shaft 2 equipped with the balloon or stent from the first shaft 1. This makes it easier to prevent the coating layer provided on the outer surface 63 of the balloon or stent from peeling off when the balloon or stent is placed at the treatment site.

[0272] The coating layer can be formed by applying a coating agent to the outer surface of the balloon or stent. The coating layer may be formed only on a portion of the outer surface of the balloon or stent, or may be formed on the entire outer surface of the balloon or stent.

[0273] For example, the coating layer may include a lubricious coating agent or a biologically active agent.

[0274] 21 , in a state in which the maximum outer diameter of the second portion 62 of the diameter-expanding portion 60 is larger than the maximum outer diameter of the first tubular portion 10, the maximum inner diameter of the bag-shaped body portion 20 is preferably larger than the maximum inner diameter of the first tubular portion 10. This makes it easier for the bag-shaped body portion 20 to follow the shape of the diameter-expanding portion 60.

[0275] When the flow path 40 is pressurized to a pressure equal to or greater than the first predetermined pressure by injection of a fluid into the flow path 40, it is preferable that the surface of the bulging portion 30 located on the inner side of the first tubular portion 10 in the radial direction y abuts against the expanding / contracting diameter portion 60, as shown in Figure 21. This makes it easier to suppress movement of the second shaft 2 in the longitudinal direction of the first shaft 1.

[0276] When the flow path 40 is pressurized to a pressure equal to or greater than the first predetermined pressure by injection of a fluid, the inner cavity 11 of the first tubular portion 10 is preferably blocked by the expanded bulge portion 30 or the expanded / contracted diameter portion 60, as shown in Fig. 21 . The inner cavity 11 of the first tubular portion 10 may be blocked by the expanded bulge portion 30 and the expanded / contracted diameter portion 60, or may be blocked only by the expanded / contracted diameter portion 60. The inner cavity 11 of the first tubular portion 10 may have a portion blocked by the expanded bulge portion 30 and the expanded / contracted diameter portion 60, and a portion blocked only by the expanded / contracted diameter portion 60. This makes it easier to suppress movement of the second shaft 2 in the longitudinal direction of the first shaft 1.

[0277] Although not shown, the proximal end of the catheter 100 is provided with the hub 72, a controller used to operate the catheter 100, other devices, and the like, and may further include a mechanism capable of fixing these components so that their relative positions do not change. Preferably, this mechanism is capable of fixing at least two of the hub 72, the controller, and other devices so that their relative positions do not change. Here, being capable of being fixed means that the relative positions of the at least two components can be fixed so that they do not change, and that the fixed state can be released so that the relative positions of the at least two components can be changed.

[0278] (Third embodiment) From here, a third embodiment of the first invention will be described. Note that explanations of the lengths and constituent materials of the components and parts that have already been explained will be omitted. The explanations in the first and second embodiments can be referenced as appropriate.

[0279] A third embodiment of the first invention is a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction of the first shaft; a bag-shaped body portion located distal to the first tubular portion and formed in an annular shape; a bulging portion bulging outward in the radial direction of the first tubular portion; and a flow path having a space in which a fluid can be injected up to the bag-shaped body portion and a space in which a fluid can be injected up to the bulging portion; and a second shaft comprising: a second tubular portion; and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion, the second shaft being disposed in the inner cavity of the first shaft, wherein a first portion which is a part of the expanding / contracting diameter portion is located in the inner cavity of the first shaft, and a second portion of the expanding / contracting diameter portion located distal to the first portion. the second portion, which is a portion that is inscribed within the first shaft, is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer surface of the first portion is inscribed within the first shaft, and the bulging portion bulges outward in the radial direction of the first tubular portion, and the bulging portion bulges outward in the radial direction of the first tubular portion when the bulging portion is pressurized by injecting a fluid into the flow path, and when the expandable diameter portion is not positioned in the lumen of the distal end of the bag-like body portion, the minimum inner diameter of the bag-like body portion when the bag-like body portion is pressurized by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-like body portion when it is not pressurized by injecting a fluid into the flow path.

[0280] The overall configuration of the third embodiment will be described with reference to Figures 37 to 55. These figures show a catheter 100 having a first shaft 1 equipped with a first tubular portion 10, a bag-shaped portion 20, a bulging portion 30, and a flow path 40, and a second shaft 2 disposed in the lumen of the first shaft 1. In these figures, the longitudinal direction of the first tubular portion 10 is indicated by x, and the radial direction is indicated by y.

[0281] FIG. 37 is an enlarged cross-sectional view (partial side view) of a distal portion of a catheter according to an embodiment of the present invention, illustrating a state in which pressurization by injection of fluid into the flow path is not being performed. FIG. 38 is a cross-sectional view of the catheter shown in FIG. 37 taken along line XXXVIII-XXXVIII. FIG. 39 is a cross-sectional view (partial side view) of the catheter shown in FIG. 37 when pressurized by injection of fluid into the flow path. FIG. 40 is a cross-sectional view (partial side view) of the catheter shown in FIG. 37 when pressurized by injection of fluid into the flow path. FIG. 41 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 42 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 41. FIG. 43 is a cross-sectional view of the first shaft shown in FIG. 42 taken along line XLIII-XLIII. FIG. 44 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 42 when pressurization by injection of fluid into the flow path is not being performed. FIG. 45 is a cross-sectional view of the first shaft shown in FIG. 44 when it is pressurized by injecting a fluid into the flow channel. FIG. 46 is a cross-sectional view of the first shaft shown in FIG. 44 when it is pressurized by injecting a fluid into the flow channel. FIG. 47 is a cross-sectional view of the first shaft shown in FIG. 46 taken along line XLVII-XLVII. FIG. 48 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 47. FIG. 49 is a cross-sectional view showing a modified example of the first shaft shown in FIG. 47. FIG. 50 is a cross-sectional view of the first shaft shown in FIG. 44 taken along line L-L. FIG. 51 is a cross-sectional view of a modified example of the first shaft shown in FIG. 44. FIG. 52 is a cross-sectional view of the first shaft shown in FIG. 51 taken along line LII-LII. FIG. 53 is a cross-sectional view of a modified example of the first shaft shown in FIG. 44. FIG. 54 is a cross-sectional view of the first shaft shown in FIG. 53 taken along line LIV-LIV. FIG. 55 is a cross-sectional view showing a modified example of the first shaft shown in FIG.

[0282] As shown in FIGS. 37 to 40, the catheter 100 has a first shaft 1 and a second shaft 2.

[0283] The first shaft 1 includes a first cylindrical portion 10 , a bag-shaped portion 20 , a bulging portion 30 , and a flow path 40 .

[0284] As shown in FIGS. 37 to 40, the first shaft 1 has a longitudinal direction and an inner cavity extending in the longitudinal direction.

[0285] 37 to 40 , the first shaft 1 has a first tubular portion 10 extending in the longitudinal direction of the first shaft 1. The first tubular portion 10 has a longitudinal direction x and a radial direction y that is a direction perpendicular to the longitudinal direction x. The first tubular portion 10 preferably has an inner cavity 11 extending in the longitudinal direction x of the first tubular portion 10.

[0286] As shown in Figures 37, 39, and 40, the bag-like body portion 20 is a portion having a bag-like shape. Because the bag-like body portion 20 is bag-shaped, it is preferable that it has an internal space 23 therein. Furthermore, the bag-like body portion 20 is a portion formed in an annular shape. It is preferable that the bag-like body portion 20 has an inner cavity 25 formed therein by being formed in an annular shape. The bag-like body portion 20 is located distal to the first tubular portion 10.

[0287] As shown in Figures 39 and 40, the bulging portion 30 is a portion that bulges outward in the radial direction y of the first cylindrical portion 10 by expanding.

[0288] 37 to 40, the flow path 40 has a space into which the fluid can be injected up to the bag-shaped body portion 20 and a space into which the fluid can be injected up to the bulging portion 30. The space into which the fluid can be injected up to the bag-shaped body portion 20 and the space into which the fluid can be injected up to the bulging portion 30 may be connected to each other, or may be separate spaces that are not connected to each other.

[0289] The inner cavity of the first shaft 1 is preferably configured by the inner cavity 11 of the first tubular portion 10 and the inner cavity 25 of the bag-like body portion 20 communicating with each other.

[0290] The second shaft 2 includes a second cylindrical portion 50 and an expanded / contracted diameter portion 60 , and is disposed in the inner cavity of the first shaft 1 .

[0291] The second cylindrical portion 50 preferably extends in the longitudinal direction of the first shaft 1. The second cylindrical portion 50 preferably has an inner cavity extending in the longitudinal direction of the first shaft 1.

[0292] The expandable / contractable section 60 is a section that can expand and contract in diameter, and is fixed to the distal part of the second tubular section 50 .

[0293] 40 , a first portion 61, which is a part of the expandable / contractable section 60, is located in the lumen of the first shaft 1, and a second portion 62, which is a portion of the expandable / contractable section 60 located distal to the first portion 61, is located outside the first shaft 1. Furthermore, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular section 10, and the outer surface of the first portion 61 is inscribed in the first shaft 1. With the above configuration, the length of the expandable / contractable section 60 that contacts the treatment area can be easily adjusted to the desired length.

[0294] 40 , the bulging portion 30 of the catheter 100 bulges outward in the radial direction y of the first tubular portion 10. This makes it easier to suppress movement of the first shaft 1 within the body cavity.

[0295] The bulging portion 30 is configured to bulge outward in the radial direction y of the first cylindrical portion 10 as shown in Figures 39 and 40 when pressurized by injection of fluid into the flow path 40. This causes the bulging portion 30 to bulge outward when pressurized.

[0296] 37 and 39 , when the diameter-expanding section 60 is not disposed in the lumen 25 at the distal end of the bag-shaped body section 20, the minimum inner diameter of the bag-shaped body section 20 when the bag-shaped body section 20 is pressurized by injecting fluid into the flow path 40 is configured to be larger than the minimum inner diameter of the bag-shaped body section 20 when no pressurization is performed by injecting fluid into the flow path 40. This increases the minimum inner diameter of the bag-shaped body section 20 when it is pressurized.

[0297] The catheter 100 can be used, for example, by inserting the distal end of the first shaft 1 to a treatment site, and then protruding a portion of the expandable / contractable section 60 disposed in the lumen of the first shaft 1 from the first shaft 1. When transporting the first shaft 1 to the treatment site, as shown in FIG. 37 , the first shaft 1 is not pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-like body portion 20 is smaller than the minimum inner diameter of the bag-like body portion 20 when the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40. This makes it easier to reduce the outer diameter of the bag-like body portion 20. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. After transporting the first shaft 1 to the treatment site, as shown in FIG. 39 , the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-shaped body portion 20 is larger than the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injection of fluid into the flow path 40 is not performed. This makes it easier to protrude a portion of the expandable / contractable diameter portion 60, which is disposed in the lumen of the first shaft 1, from the expanded-diameter bag-shaped body portion 20. After the bag-shaped body portion 20 is pressurized by injection of fluid into the flow path 40, as shown in FIG. 40 , the first portion 61 is located in the lumen of the first shaft 1, the second portion 62 is located outside the first shaft 1, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular portion 10, the outer surface of the first portion 61 is inscribed in the first shaft 1, and the bulging portion 30 bulges outward in the radial direction y of the first tubular portion 10. This makes it easier to adjust the length of the expandable / contractable diameter portion 60 that contacts the treatment site to a desired length. Furthermore, since the bulging portion 30 bulges outward in the radial direction y of the first tubular portion 10, the bulging portion 30 can be easily brought into contact with the wall of the body cavity, which makes it easier to suppress movement of the first shaft 1 inside the body cavity.

[0298] The first cylindrical portion 10 preferably has a distal end 10 a and a proximal end 10 b. The first cylindrical portion 10 also preferably has an inner surface 10 c facing the lumen 11 of the first cylindrical portion 10 and an outer surface 10 d facing the outside of the first cylindrical portion 10.

[0299] The outer surface 10d of the first cylindrical portion 10 is preferably coated with a hydrophilic polymer, which makes it easier to insert the first cylindrical portion 10 into a body cavity. Examples of hydrophilic polymers include poly (2-hydroxyethyl methacrylate), polyacrylamide, polyvinylpyrrolidone, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers, and polyethylene glycol.

[0300] The inner surface 10c of the first tubular portion 10 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin, or the entire inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin. This makes the first tubular portion 10 more easily slippery relative to components placed in the lumen 11 of the first tubular portion 10, thereby making it easier to improve the operability of the catheter 100.

[0301] As shown in Figure 42, the first tubular portion 10 may have a distal opening 11a at a distal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10, and may have a proximal opening 11b at a proximal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10.

[0302] As shown in Figures 41 and 42, the first tubular portion 10 can be configured to have a tapered region 13 in the proximal portion of the first tubular portion 10, whose length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x of the first tubular portion 10 decreases toward the proximal side.

[0303] 42 , it is preferable that a proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in the tapered region 13. It is more preferable that the proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in a portion that slopes so that the length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x decreases toward the proximal side. With this configuration, for example, the guidewire 4 or the second shaft 2 can be inserted into and removed from the lumen 11 of the first tubular portion 10 through the proximal opening 11b.

[0304] 41 and 42 , the first shaft 1 may further include a third tubular portion 70. A distal portion of the third tubular portion 70 is fixed to a proximal portion of the reduced diameter region 13, and a lumen 71 of the third tubular portion 70 and the flow path 40 can be configured to communicate with each other.

[0305] The third cylindrical portion 70 is a cylindrical portion having an inner cavity 71. It is preferable that the maximum outer diameter of the third cylindrical portion 70 is smaller than the maximum outer diameter of the first cylindrical portion 10. Furthermore, the minimum outer diameter of the third cylindrical portion 70 may be smaller than the minimum outer diameter of the first cylindrical portion 10.

[0306] For the configuration of the third cylindrical portion 70, such as the material constituting the third cylindrical portion 70, reference can be made to the description of the first cylindrical portion 10. The material constituting the third cylindrical portion 70 and the material constituting the first cylindrical portion 10 may be the same or different.

[0307] It is preferable that a lubricating coating layer containing PTFE, PFA, or the like is formed on the outer surface of the third cylindrical portion 70. This makes it easier to insert the third cylindrical portion 70 into a body cavity.

[0308] The third cylindrical portion 70 may be provided with a position indication marker for indicating the length of the inserted portion when the first shaft 1 is inserted into a body cavity. The position indication marker may be formed, for example, by inserting the third cylindrical portion 70 into the inner cavity of a marker tube and welding it, or may be formed by peeling off a part of the lubricating coating layer containing the above-mentioned PTFE, PFA, or the like.

[0309] The position indication markers can be provided, for example, at positions 600 mm, 900 mm, 1200 mm, etc. from the distal end of the first shaft 1.

[0310] It is preferable that the distal portion of the third tubular portion 70 and the proximal portion of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is more preferable that the distal end of the third tubular portion 70 and the proximal end of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is preferable that the lumen 71 of the third tubular portion 70 does not communicate with the lumen 11 of the first tubular portion 10.

[0311] 41 , the catheter 100 preferably further includes a hub 72 connected to the proximal end of the first shaft 1. The hub 72 may be connected to the third cylindrical portion 70. In this case, the hub 72 preferably includes a port therein that communicates with the lumen 71 of the third cylindrical portion 70, and a fluid can be injected into the lumen 71 of the third cylindrical portion 70 via the port.

[0312] Although not shown, the first shaft 1 may not include the third cylindrical portion 70, and the proximal end 10b of the first cylindrical portion 10 may be directly connected to the hub 72. In this case, it is preferable that the hub 72 has a port therein that communicates with the flow path 40, and that a fluid can be injected into the flow path 40 via the port.

[0313] The material constituting the bag-shaped body portion 20 can be, for example, any of the materials listed as being constituting the first tubular portion 10. The material constituting the bag-shaped body portion 20 and the material constituting the first tubular portion 10 may be the same or different.

[0314] As shown in Figures 41 and 42, the proximal portion of the bag-shaped body portion 20 may be connected to the distal portion of the first tubular portion 10, or the proximal end of the bag-shaped body portion 20 may be connected to the distal end 10a of the first tubular portion 10.

[0315] The minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. In particular, as shown in FIG. 44 , when pressurization by injecting a fluid into the flow path 40 is not performed, the minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. This makes it less likely that the first shaft 1 will get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. From the viewpoint of enhancing this effect, as shown in FIG. 44 , when pressurization by injecting a fluid into the flow path 40 is not performed, the maximum outer diameter of the bag-shaped body portion 20 is more preferably equal to or smaller than the outer diameter of the first tubular portion 10. Note that, as shown in FIGS. 45 and 46 , even when the bag-shaped body portion 20 is pressurized by injecting a fluid into the flow path 40, the minimum outer diameter of the bag-shaped body portion 20 may be smaller than the outer diameter of the first tubular portion 10. As shown in Figure 40, when the expansion / contraction diameter portion 60 is placed in the inner cavity 25 of the bag-shaped body portion 20 and the expansion / contraction diameter portion 60 expands, the maximum outer diameter of the bag-shaped body portion 20 may be greater than or equal to the outer diameter of the first tubular portion 10.

[0316] The bag-shaped body portion 20 provided distal to the distal end 10a of the first tubular portion 10 preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 44 , when pressurization by injecting a fluid into the flow path 40 is not performed, the bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 44 , when pressurization by injecting a fluid into the flow path 40 is not performed, the entire bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. Note that, as shown in FIGS. 45 and 46 , when pressurization by injecting a fluid into the flow path 40 is performed, the bag-shaped body portion 20 may have a tapered portion whose outer diameter decreases toward the distal side. 45 and 46 , the entire bag-shaped body portion 20 may be a tapered portion whose outer diameter decreases toward the distal side when the bag-shaped body portion 20 is pressurized by injection of a fluid into the flow path 40. As shown in Fig. 40 , when the expandable / contractable diameter portion 60 is disposed in the lumen 25 of the bag-shaped body portion 20 and the expandable / contractable diameter portion 60 expands in diameter, the bag-shaped body portion 20 may have a tapered portion whose outer diameter decreases toward the proximal side, or the entire bag-shaped body portion 20 may be a tapered portion whose outer diameter decreases toward the proximal side.

[0317] Although the bag-shaped body portion 20 is formed in an annular shape, it may also have a hollow truncated cone shape, as shown in Figures 41 to 43. Although not shown, the bag-shaped body portion 20 may also have a hollow truncated polygonal pyramid shape, or a shape that combines a hollow truncated cone and a hollow truncated polygonal pyramid, for example, a shape in which a hollow truncated cone and a hollow truncated polygonal pyramid are connected in the longitudinal direction x of the first tubular portion 10.

[0318] The bulging portion 30 preferably bulges outward in the radial direction y of the first tubular portion 10 when the bulging portion 30 is pressurized to a third predetermined pressure or higher by injecting a fluid into the flow path 40. This causes the bulging portion 30 to bulge when the bulging portion 30 is pressurized to a third predetermined pressure or higher. Furthermore, when the expandable / contractable portion 60 is not disposed in the lumen 25 at the distal end of the bag-like body portion 20, the minimum inner diameter of the bag-like body portion 20 when the bulging portion 30 is pressurized to a fourth predetermined pressure or higher by injecting a fluid into the flow path 40 is preferably larger than the minimum inner diameter of the bag-like body portion 20 when the bulging portion 30 is not pressurized by injecting a fluid into the flow path 40. This causes the minimum inner diameter of the bag-like body portion 20 to become larger when the bulging portion 30 is pressurized to a fourth predetermined pressure or higher.

[0319] The third predetermined pressure and the fourth predetermined pressure may be the same value or may be different values.

[0320] The bulging portion 30 may be bulged first, and then the bulging portion 30 may be expanded in diameter. Alternatively, the bulging portion 30 may be bulged first, and then the bulging portion 30 may be expanded in diameter. The bulging portion 20 may be expanded in diameter and the bulging portion 30 may be bulged simultaneously.

[0321] A space into which fluid can be injected up to the bulging portion 30 and a space into which fluid can be injected up to the bag-shaped body portion 20 may be provided separately. The space into which fluid can be injected up to the bulging portion 30 and the space into which fluid can be injected up to the bag-shaped body portion 20 may be connected, or the space into which fluid can be injected up to the bulging portion 30 and the space into which fluid can be injected up to the bag-shaped body portion 20 may partially overlap.

[0322] The fourth predetermined pressure may be equal to or greater than the third predetermined pressure. In a case where the flow path 40 for injecting fluid into the bulging portion 30 and the flow path 40 for injecting fluid into the bag-shaped body portion 20 are connected or where the flow path 40 for injecting fluid into the bulging portion 30 and the flow path 40 for injecting fluid into the bag-shaped body portion 20 partially overlap, and the fourth predetermined pressure is greater than the third predetermined pressure, the bulging portion 30 can be inflated and then the bag-shaped body portion 20 can be expanded in diameter. More specifically, the first shaft 1 shown in FIG. 44 in a state where no fluid is being injected into the flow path 40 is pressurized to a pressure equal to or greater than the third predetermined pressure by the injection of fluid into the flow path 40, causing the bulging portion 30 to inflate as shown in FIG. 45. Thereafter, the minimum inner diameter of the bag-shaped body portion 20 increases as shown in FIG. 46 by the injection of fluid into the flow path 40 and the pressurized pressure equal to or greater than the fourth predetermined pressure, which is greater than the third predetermined pressure. In cases where the space through which fluid can be injected up to the bulging portion 30 and the space through which fluid can be injected up to the bag-shaped body portion 20 are connected, or where the space through which fluid can be injected up to the bulging portion 30 and the space through which fluid can be injected up to the bag-shaped body portion 20 partially overlap, and the fourth predetermined pressure is the same as the third predetermined pressure, the expansion of the diameter of the bag-shaped body portion 20 and the expansion of the bulging portion 30 can be performed simultaneously. More specifically, when the first shaft 1 shown in FIG. 44 is in a state in which no fluid is being injected into the flow path 40, the first shaft 1 is pressurized to a pressure equal to or greater than the third predetermined pressure (fourth predetermined pressure) by injecting fluid into the flow path 40, and as shown in FIG. 46 , the expansion portion 30 expands and the minimum inner diameter of the bag-shaped body portion 20 increases. This configuration makes it easier to suppress movement of the first shaft 1 within the body cavity when a portion of the second shaft 2 disposed in the lumen of the first shaft 1 is protruded from the expanded-diameter bag-shaped body portion 20. Note that an embodiment in which the fourth predetermined pressure is lower than the third predetermined pressure is also acceptable. In this case, it is preferable that a portion of the second shaft 2 disposed in the lumen of the first shaft 1 protrudes from the bag-shaped body portion 20 after the bulging portion 30 is bulged.

[0323] 42 to 46, the bag-shaped body portion 20 can be configured to have an inner surface portion 21 facing the lumen 25 of the bag-shaped body portion 20, and an outer surface portion 22 facing the exterior of the bag-shaped body portion 20. The inner surface portion 21 has an inner surface facing the lumen 25, and the outer surface portion 22 has an outer surface facing the exterior. The inner surface portion 21 has a distal end 21a and a proximal end 21b. The outer surface portion 22 has a distal end 22a and a proximal end 22b. It is preferable that an internal space 23 exists between the inner surface portion 21 and the outer surface portion 22.

[0324] It is preferable that the elongation percentage (%) of the length from the distal end 21 a to the proximal end 21 b of the inner surface portion 21 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized at or above the fourth predetermined pressure by injecting a fluid into the flow path 40 is greater than the elongation percentage (%) of the length from the distal end 22 a to the proximal end 22 b of the outer surface portion 22 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized at or above the fourth predetermined pressure by injecting a fluid into the flow path 40. With the above-described configuration, when the bag-shaped body portion 20 is pressurized to or above the fourth predetermined pressure by injecting a fluid, the inner surface portion 21, which is more elongate than the outer surface portion 22, stretches, and the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. This allows the minimum inner diameter of the bag-shaped body portion 20 when it is pressurized to a fourth predetermined pressure or higher by injecting a fluid into the flow path 40 to be larger than the minimum inner diameter of the bag-shaped body portion 20 when it is not pressurized by injecting a fluid into the flow path 40. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 44 to the state shown in FIG. 46. Therefore, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site, it is possible to make the second shaft 2 more likely to protrude from the expanded diameter portion. The elongation rate (%) is calculated by dividing the length of each portion after pressurization by the length of each portion before pressurization.

[0325] The inner surface portion 21 and the outer surface portion 22 may be made of the same material or different materials.

[0326] When the inner surface portion 21 and the outer surface portion 22 are made of the same material, for example, it is preferable that the thickness of the inner surface portion 21 is thinner than the thickness of the outer surface portion 22. This makes the inner surface portion 21 more stretchable than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in Fig. 44 to the state shown in Fig. 46. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0327] When the inner surface portion 21 and the outer surface portion 22 are made of different materials, for example, it is preferable that the elongation rate of the material making up the inner surface portion 21 be higher than that of the material making up the outer surface portion 22. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material making up the inner surface portion 21 and a sample made of the material making up the outer surface portion 22, formed to the same shape as the sample, are prepared, and then the samples are gripped at one end and the other end so that the grip width is the same length and pulled with the same strength (N). This makes the inner surface portion 21 more elongate than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to increase compared to before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in FIG. 44 to the state shown in FIG. 46. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0328] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, the angle α between the inner surface portion 21 and the outer surface portion 22 when pressurization by injecting a fluid into the flow path 40 is not performed is preferably an acute angle, as shown in FIG. 44 . The angle α may be 85° or less, 80° or less, or 70° or less. The angle α may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity.

[0329] In a cross section of the first cylindrical portion 10 parallel to the longitudinal direction x, the angle ε formed between the inner surface portion 21 and the outer surface portion 22 when the first cylindrical portion 10 is pressurized to a third predetermined pressure or higher by injection of a fluid into the flow path 40 is preferably an acute angle, as shown in Fig. 45. The angle ε may be 85° or less, 80° or less, or 70° or less. The angle ε may be 1° or more, 3° or more, or 5° or more.

[0330] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, when the first tubular portion 10 is pressurized to a fourth predetermined pressure or higher by the injection of a fluid into the flow path 40, the angle ζ between the inner surface portion 21 and the outer surface portion 22 is preferably an acute angle, as shown in FIG. 46 . The angle ζ may be 85° or less, 80° or less, or 70° or less. The angle ζ may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the thickness of the distal end of the bag-shaped body portion 20. In other words, it makes it easier to shorten the length between the inner surface of the inner surface portion 21 and the outer surface of the outer surface portion 22. Therefore, it makes it easier to increase the inner diameter of the distal end of the bag-shaped body portion 20 when the first tubular portion 10 is pressurized to a fourth predetermined pressure or higher by the inflow of a fluid into the flow path 40. Therefore, even when the second shaft 2 is placed in the inner cavity 11 of the first tubular portion 10 and transported to the treatment site, it is possible to easily protrude the second shaft 2 from the expanded diameter portion.

[0331] As shown in Figures 42 and 43 , the internal space 23 is a space formed within the wall that constitutes the annular bag-shaped body portion 20. In the example shown in Figures 42 and 43 , the internal space 23 is a space that exists within the wall that forms the inner cavity 25 of the bag-shaped body portion 20. As shown in Figures 42 and 43 , the internal space 23 preferably exists throughout the entire circumferential direction within the wall of the bag-shaped body portion 20. In other words, the internal space 23 is preferably a space that is circumferentially connected within the wall of the bag-shaped body portion 20. Although not shown, the internal space 23 may exist only partially within the circumferential direction within the wall of the bag-shaped body portion 20.

[0332] It is preferable that the internal space 23 does not communicate with the lumen 11 of the first tubular portion 10. It is also preferable that the internal space 23 does not communicate with the lumen 25 of the bag-shaped body portion 20. This makes it easier for the fluid injected into the flow path 40 to efficiently flow into the internal space 23 formed in the bag-shaped body portion 20.

[0333] 44 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when pressurization by injection of a fluid into the flow path 40 is not being performed, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0334] 46 , when the bag-shaped body portion 20 is pressurized to a fourth predetermined pressure or higher by the injection of fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, when the minimum internal diameter of the bag-shaped body portion 20 increases as a result of the bag-shaped body portion 20 being pressurized to a fourth predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0335] 44 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when pressurization by injection of a fluid into the flow path 40 is not being performed, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0336] 46 , when the bag-shaped body portion 20 is pressurized to a fourth predetermined pressure or higher by the injection of fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, when the minimum inner diameter of the bag-shaped body portion 20 increases as a result of the bag-shaped body portion 20 being pressurized to a fourth predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0337] The length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when no pressurization is performed by injecting a fluid into the flow path 40 and the length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when the bag-shaped body portion 20 is pressurized to a fourth predetermined pressure or higher by injecting a fluid into the flow path 40 may be the same or different.

[0338] The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0339] The length of the bag-shaped body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-shaped body portion 20 is pressurized to a fourth predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-shaped body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-shaped body portion 20 is pressurized to a fourth predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0340] The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed is preferably a size that allows the guide wire 4 to be inserted therethrough. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 30% or more, 35% or more, or 40% or more of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 70% or less, 65% or less, or 60% or less of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc. Furthermore, the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 2.00 mm or less, 1.95 mm or less, 1.90 mm or less, etc.

[0341] As shown in Fig. 44 , in a state where pressurization by injection of a fluid into the flow path 40 is not performed, the inner diameter of the bag-shaped body portion 20 is preferably smallest at the distal end of the bag-shaped body portion 20. As shown in Fig. 45 , in a state where pressurization to a third predetermined pressure or higher by injection of a fluid into the flow path 40 is performed, the inner diameter of the bag-shaped body portion 20 is preferably smallest at the distal end of the bag-shaped body portion 20. In a state where pressurization to a fourth predetermined pressure or higher by injection of a fluid into the flow path 40 is performed, the inner diameter of the bag-shaped body portion 20 may be smallest at either the proximal end or the distal end of the bag-shaped body portion 20.

[0342] The minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 0.31 mm or more, 0.36 mm or more, 0.41 mm or more, etc. Furthermore, the minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 3.00 mm or less, 2.90 mm or less, 2.80 mm or less, etc.

[0343] As shown in Fig. 44 , in a state where pressurization by injection of fluid into the flow path 40 is not performed, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter. As shown in Fig. 45 , in a state where pressurization to a third predetermined pressure or higher by injection of fluid into the flow path 40 is performed, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter. As shown in Fig. 46 , in a state where pressurization to a fourth predetermined pressure or higher by injection of fluid into the flow path 40 is performed, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter.

[0344] The materials constituting the bulging portion 30 may be the same as or different from the materials constituting the first tubular portion 10 or the materials constituting the balloon.

[0345] 46 to 49 , the bulging portion 30 may be a portion that bulges outward in the radial direction y of the first tubular portion 10 by a portion of the first tubular portion 10 expanding. Although not shown, the bulging portion 30 may have a configuration separate from the first tubular portion 10. For example, the bulging portion 30 may be a bag-shaped member disposed outside the first tubular portion 10, and the fluid may be injected through a tubular member connected to the bag-shaped member. In this case, the inner cavity of the tubular member functions as the flow path 40.

[0346] 45 and 46 , when the bulging portion 30 is a portion that bulges outward in the radial direction y of the first tubular portion 10 due to the bulging of a portion of the first tubular portion 10, it is preferable that the portion of the first tubular portion 10 that constitutes the bulging portion 30 is thinner than the portion of the first tubular portion 10 other than the bulging portion 30. This makes the portion of the first tubular portion 10 that constitutes the bulging portion 30 more easily stretchable than the portion of the first tubular portion 10 other than the bulging portion 30, making it easier to bulge the portion of the first tubular portion 10 that constitutes the bulging portion 30. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 44 to the state shown in FIGS. 45 and 46 .

[0347] As shown in Figures 45 and 46, when the bulging portion 30 is a portion of the first tubular portion 10 that bulges outward in the radial direction y of the first tubular portion 10 due to expansion of a portion of the first tubular portion 10, it is preferable that the elongation rate of the material constituting the bulging portion 30 of the first tubular portion 10 be higher than the elongation rate of the material constituting the rest of the first tubular portion 10. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material constituting the bulging portion 30 of the first tubular portion 10 and a sample formed to the same shape as the sample made of the material constituting the rest of the first tubular portion 10 other than the bulging portion 30 are prepared, and one end and the other end of each sample are gripped to the same length and pulled with the same strength (N). This makes the bulging portion 30 more elongate than the rest of the first tubular portion 10, making the bulging portion 30 more likely to bulge when pressurized. In the example described above, the first shaft 1 is more likely to change from the state shown in Figure 44 to the state shown in Figures 45 and 46.

[0348] The bulge portion 30 may be present in a portion of the circumference of the first tubular portion 10 as shown in Figures 47 and 48, or may be present in the entire circumference of the first tubular portion 10 as shown in Figure 49.

[0349] The first shaft 1 may have only one bulging portion 30 or may have a plurality of bulging portions 30 .

[0350] 47 to 49 , the bulging height 30L of the bulging portion 30 in the radial direction y of the first cylindrical portion 10 may vary in the circumferential direction of the first cylindrical portion 10. The bulging height 30L of the bulging portion 30 refers to the length of the bulging portion in the radial direction y of the first cylindrical portion 10. Although not shown, the bulging height 30L of the bulging portion 30 in the radial direction y of the first cylindrical portion 10 may be constant and not vary in the circumferential direction of the first cylindrical portion 10.

[0351] The frictional force of the outer surface of the bulging portion 30 is preferably higher than the frictional force of the outer surface 10d of the first tubular portion 10. More preferably, the frictional force of the outer surface of the bulging portion 30 when pressurized by injecting a fluid into the flow path 40 is higher than the frictional force of the outer surface 10d of the first tubular portion 10 when pressurized by injecting a fluid into the flow path 40. The frictional force of each surface can be adjusted by coating, surface roughness, changing the material, etc. This configuration can make it easier to suppress movement of the first shaft 1 within the body cavity. Note that, as shown in FIG. 45 , when the bulging portion 30 is a portion of the first tubular portion 10 that bulges outward in the radial direction y of the first tubular portion 10 due to partial expansion of the first tubular portion 10, the frictional force of the outer surface of the bulging portion 30 is preferably higher than the frictional force of the outer surface 10d of the first tubular portion 10 that constitutes the first tubular portion 10 other than the bulging portion 30. It is more preferable that the frictional force of the outer surface of the bulge portion 30 when it is pressurized by injecting a fluid into the flow path 40 is higher than the frictional force of the outer surface 10d of the first tubular portion 10 that constitutes the part of the first tubular portion 10 other than the bulge portion 30 when it is pressurized by injecting a fluid into the flow path 40.

[0352] 46 , the bulging portion 30 is preferably located more proximal than the proximal end of the bag-shaped body portion 20. Alternatively, the bulging portion 30 may be located more proximal than the distal end 10 a of the first tubular portion 10. The bulging portion 30 is preferably provided in the distal portion of the first tubular portion 10.

[0353] 37 to 40, 44 to 46, and 50 to 52, the first tubular portion 10 can have a wall 12 that forms the lumen 11, and the flow path 40 can be formed within the wall 12 of the first tubular portion 10. This configuration eliminates the need to provide a separate member for forming the flow path 40, making it easier to make the catheter 100 thinner.

[0354] 44 and 50, the first tubular portion 10 may have a first outer cylinder 15 and a first inner cylinder 14 disposed in the lumen of the first outer cylinder 15, and the flow path 40 may be a space defined by an inner surface 15c of the first outer cylinder 15 and an outer surface 14d of the first inner cylinder 14. This configuration eliminates the need to provide a separate member for forming the flow path 40, making it easier to make the catheter 100 thinner.

[0355] 50 , the distance between the inner surface 15c of the first outer cylinder 15 and the outer surface 14d of the first inner cylinder 14 is preferably 0.01 mm or more and 1.0 mm or less, so that pressure loss can be reduced when the fluid is delivered to the distal end through the flow path 40.

[0356] The first outer cylinder 15 may have a distal end and a proximal end, and may have a lumen extending in the longitudinal direction x. The same applies to the first inner cylinder 14.

[0357] When the bag-shaped body portion 20 changes from a state in which it is not pressurized by injecting a fluid into the flow path 40 to a state in which it is pressurized at or above the fourth predetermined pressure by injecting a fluid into the flow path 40, the elongation percentage (%) of the length from the distal end 21a to the proximal end 21b of the inner surface portion 21 is preferably greater than the elongation percentage (%) of the length from the distal end 10a to the proximal end 10b of the first tubular portion 10. This configuration is particularly preferable when the flow path 40 is formed within the wall 12 of the first tubular portion 10. The higher elongation percentage (%) of the bag-shaped body portion 20 than that of the first tubular portion 10 makes it possible to make the first tubular portion 10 less susceptible to deformation by fluid pressure, thereby facilitating the stable supply of fluid injected into the flow path 40 to the bag-shaped body portion 20.

[0358] 51 and 52 , the flow path 40 may extend linearly in the longitudinal direction x of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10. Although not shown, the flow path 40 may be formed in a wave shape within the wall 12 of the first cylindrical portion 10, or the flow path 40 may be formed in a spiral shape that circles around the inner cavity 11 of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10.

[0359] 51 and 52 , when the flow path 40 extends linearly in the longitudinal direction x of the first cylindrical portion 10 within the wall 12 of the first cylindrical portion 10, it is preferable that the internal space 23 that is continuous throughout the entire circumferential direction of the first cylindrical portion 10 within the wall of the bag-shaped body portion 20 communicates with the linear flow path 40. This allows the fluid injected into the flow path 40 to be injected into the internal space 23 of the bag-shaped body portion 20.

[0360] The flow path 40 may be formed not only within the wall 12 of the first cylindrical portion 10, but also by providing a component separate from the first cylindrical portion 10. For example, as shown in FIGS. 53 and 54 , the flow path 40 may be formed by a fourth cylindrical portion 41 disposed in the lumen 11 of the first cylindrical portion 10. The fourth cylindrical portion 41 is a cylindrical portion having a lumen, and the lumen of the fourth cylindrical portion 41 is the flow path 40. By disposing the fourth cylindrical portion 41 in the lumen 11 of the first cylindrical portion 10, the catheter 100 can be made thinner. Although not shown, the fourth cylindrical portion 41 may also be disposed outside the first cylindrical portion 10.

[0361] When the flow path 40 is formed by the fourth cylindrical portion 41, it is preferable that the distal end portions of the bag-shaped body portion 20 and the fourth cylindrical portion 41 are fixed together, as shown in Figures 53 and 54. It is also preferable that the bag-shaped body portion 20 has a hole 24 that connects the flow path 40 with the internal space 23. This allows the fluid injected into the flow path 40 formed by the fourth cylindrical portion 41 to be injected into the internal space 23 of the bag-shaped body portion 20.

[0362] For the configuration of the fourth cylindrical portion 41, such as the material constituting the fourth cylindrical portion 41, reference can be made to the portion described for the first cylindrical portion 10. The material constituting the first cylindrical portion 10, the material constituting the third cylindrical portion 70, and the material constituting the fourth cylindrical portion 41 may be the same or different.

[0363] The space into which the fluid can be injected up to the bulging portion 30 may be connected to the space into which the fluid can be injected up to the bag-shaped body portion 20. Also, a part of the space into which the fluid can be injected up to the bulging portion 30 may overlap a part of the space into which the fluid can be injected up to the bag-shaped body portion 20.

[0364] The fluid to be introduced into the flow channel 40 is not particularly limited, but may be, for example, a liquid such as physiological saline, a contrast medium, or a mixture thereof, or a gas such as air, nitrogen, or carbon dioxide.

[0365] The fluid injected up to the bag-shaped body portion 20 may pass through a space through which the fluid can be injected up to the bulging portion 30. The fluid injected up to the bulging portion 30 may pass through a space through which the fluid can be injected up to the bag-shaped body portion 20.

[0366] The fluid is preferably radiopaque. By injecting a radiopaque fluid, the distal end of the bag-shaped body portion 20 can be more easily visualized, and therefore the proximal end of the expandable diameter portion 60 that contacts the treatment site can be more easily visualized.

[0367] 37 and 38 , a reinforcing member 16 may be disposed between the flow path 40 and the lumen 11 of the first tubular portion 10. This makes it possible to more easily prevent the flow path 40 from collapsing even when a member that expands in diameter is disposed in the lumen of the first shaft 1.

[0368] The reinforcing member 16 may be made of metal. The reinforcing member 16 may be made of resin. As the metal or resin constituting the reinforcing member 16, the materials listed as the materials constituting the first tubular portion 10 can be used.

[0369] The reinforcing member 16 is preferably configured by a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof. The wire may be a solid wire or a twisted wire.

[0370] 55 , in a state where pressurization by injection of a fluid into the flow path 40 is not being performed, the first tubular portion 10 may have a protrusion 17 that protrudes inward in the radial direction y of the first tubular portion 10. In other words, the protrusion 17 is a portion that protrudes inward in the radial direction y of the first tubular portion 10 regardless of whether or not a fluid is injected into the flow path 40. This makes it easier to suppress movement of a member disposed in the lumen of the first shaft 1 in the longitudinal direction x of the first tubular portion 10.

[0371] The protruding height 17L of the protruding portion 17 and the protruding height 30L of the bulging portion 30 may be the same or different. The protruding height 17L of the protruding portion 17 may be higher than the protruding height 30L of the bulging portion 30. The protruding height 17L of the protruding portion 17 may be lower than the protruding height 30L of the bulging portion 30. The protruding height 17L of the protruding portion 17 refers to the length of the protruding portion in the radial direction y of the first cylindrical portion 10. The protruding height 30L of the bulging portion 30 refers to the length of the bulging portion in the radial direction y of the first cylindrical portion 10.

[0372] A radiopaque portion 3 may be provided in at least one of the sac-shaped body portion 20 and a region extending 10 cm proximally from the distal end 10a of the first tubular portion 10. This configuration makes it possible to visually confirm the position of the distal end of the catheter 100 using an X-ray imaging device. Figures 53 and 54 show an embodiment in which the radiopaque portion 3 is provided in the first tubular portion 10, while Figures 37 to 40 show an embodiment in which the radiopaque portion 3 is provided in the sac-shaped body portion 20.

[0373] The radiopaque portion 3 may be provided only in the bag-shaped body portion 20. The radiopaque portion 3 may be provided only in a region from the distal end 10a of the first cylindrical portion 10 to a position 10 cm proximal to the bag-shaped body portion 20. The radiopaque portion 3 may be provided both in the bag-shaped body portion 20 and in a region from the distal end 10a of the first cylindrical portion 10 to a position 10 cm proximal to the bag-shaped body portion 20.

[0374] 40, it is preferable that an X-ray opaque portion be provided at the distal end of the bag-shaped body portion 20. This makes it easier to visualize the proximal end of the expandable / contractable portion 60 that contacts the treatment site.

[0375] The shape of the radiopaque portion 3 is preferably tubular, and examples thereof include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross section with a notch in the tube, and a coil shape with a wound wire.

[0376] The material constituting the radiopaque portion 3 may be, for example, a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt-chromium alloy, and may be a form in which radiopaque particles such as barium sulfate are dispersed in the first tubular portion 10, the bag-shaped body portion 20, or a separately provided resin member.

[0377] The second cylindrical portion 50 can be configured to have a lumen extending in the longitudinal direction of the first shaft 1. The lumen of the second cylindrical portion 50 can be used as a passage for inserting a guide wire 4 or the like, as shown in Figures 37 to 40 .

[0378] As shown in Figures 37 to 40, the second tubular portion 50 may be configured to include a second outer tube 52 arranged in the inner cavity 11 of the first tubular portion 10, and a second inner tube 51 arranged in the inner cavity of the second outer tube 52.

[0379] For the configuration of the second cylindrical portion 50, such as the material constituting the second cylindrical portion 50, reference can be made to the portion described for the first cylindrical portion 10. The material constituting the first cylindrical portion 10, the material constituting the third cylindrical portion 70, the material constituting the fourth cylindrical portion 41, and the material constituting the second cylindrical portion 50 may be the same or different. Note that the material constituting the second inner cylinder 51 and the material constituting the second outer cylinder 52 may be the same or different.

[0380] The inner surface of the second inner tube 51 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface of the second inner tube 51 may be made of a fluororesin or a polyolefin resin, or the entire inner surface of the second inner tube 51 may be made of a fluororesin or a polyolefin resin. This allows the second inner tube 51 to slide easily over the guidewire 4, thereby making it easier to improve the operability of the catheter 100.

[0381] A control mechanism that suppresses movement of the second shaft 2 in the longitudinal direction x of the first tubular portion 10 may be provided in the proximal portion of the catheter 100. With this configuration, the control mechanism makes it possible to transport the catheter 100 to the treatment site while suppressing movement of the second shaft 2 in the longitudinal direction x of the first tubular portion 10, thereby making it easier to transport the catheter 100 to the treatment site.

[0382] Although not shown, one example of the control mechanism is a mode in which the third tubular portion 70 is provided with a gripping member capable of gripping the second tubular portion 50. By gripping the second tubular portion 50 with the gripping member, it is possible to temporarily suppress movement of the second tubular portion 50 in the longitudinal direction x of the first tubular portion 10. Then, by detaching the second tubular portion 50 from the gripping member, it is possible to return the second tubular portion 50 to a state in which it is movable relative to the first shaft 1. Examples of the gripping member include a rubber member provided with a slit that grips the second tubular portion 50 by pinching it, and a clip made of rigid resin.

[0383] The expandable / contractable section 60 may be, for example, a balloon or a stent that can expand and contract in diameter.

[0384] When the second tubular portion 50 has a second inner cylinder 51 and a second outer cylinder 52, and the expandable / contractable portion 60 is a balloon, it is preferable that the distal end of the expandable / contractable portion 60 is fixed to the distal portion of the second inner cylinder 51, and the proximal end of the expandable / contractable portion 60 is fixed to the distal portion of the second outer cylinder 52, as shown in Figures 37, 39, and 40. The expandable / contractable portion 60 can be expanded by injecting a fluid into the space surrounded by the second inner cylinder 51 and the second outer cylinder 52.

[0385] A stent is a tubular structure that can expand and contract in diameter, for example, composed of a mesh or other network structure. It is preferable that the stent expands and contracts, for example, in its circumferential and axial directions. Examples of stents include a coil-shaped stent made of a single linear metal or polymeric material, a metal tube or a polymeric tube cut out with a laser or the like, a stent assembled by welding linear members, and a stent made by weaving multiple linear metal members.

[0386] The stent may be a self-expanding stent or a balloon-expandable stent.

[0387] The expandable / contractable section 60 preferably uses a balloon or stent having a coating layer formed on its outer surface 63. After the catheter 100 reaches the treatment site, fluid is injected into the flow path 40 to pressurize the sac-shaped body portion 20, increasing the minimum inner diameter of the sac-shaped body portion 20 compared to before pressurization. In the example described above, the catheter 100 changes from the state shown in FIG. 37 to the state shown in FIG. 39 by injecting fluid. After the balloon or stent placed in the lumen of the first shaft 1 in the state shown in FIG. 37 is transported to the treatment site, the minimum lumen of the sac-shaped body portion 20 is enlarged as shown in FIG. 39. This makes it easier to protrude a portion of the second shaft 2 equipped with the balloon or stent from the first shaft 1. This makes it easier to prevent the coating layer provided on the outer surface 63 of the balloon or stent from peeling off when the balloon or stent is placed at the treatment site.

[0388] The coating layer can be formed by applying a coating agent to the outer surface of the balloon or stent. The coating layer may be formed only on a portion of the outer surface of the balloon or stent, or may be formed on the entire outer surface of the balloon or stent.

[0389] For example, the coating layer may include a lubricious coating agent or a biologically active agent.

[0390] 40 , in a state in which the maximum outer diameter of the second portion 62 of the diameter-expanding portion 60 is larger than the maximum outer diameter of the first tubular portion 10, the maximum inner diameter of the bag-shaped body portion 20 is preferably larger than the maximum inner diameter of the first tubular portion 10. This makes it easier for the bag-shaped body portion 20 to follow the shape of the diameter-expanding portion 60.

[0391] Although not shown, the proximal end of the catheter 100 is provided with the hub 72, a controller used to operate the catheter 100, other devices, and the like, and may further include a mechanism capable of fixing these components so that their relative positions do not change. Preferably, this mechanism is capable of fixing at least two of the hub 72, the controller, and other devices so that their relative positions do not change. Here, being capable of being fixed means that the relative positions of the at least two components can be fixed so that they do not change, and that the fixed state can be released so that the relative positions of the at least two components can be changed.

[0392] (Fourth embodiment) From here, a fourth embodiment of the first invention will be described. Note that explanations of the lengths and constituent materials of the members and parts that have already been explained will be omitted. The explanations in the first, second, and third embodiments can be referenced as appropriate.

[0393] A fourth embodiment of the first invention is a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction of the first shaft; a bag-like body portion located distal to the first tubular portion and formed in an annular shape, the bag-like body portion having an X-ray opaque portion at its distal end; and a flow path having a space into which a fluid can be injected up to the bag-like body portion; and a second shaft comprising: a second tubular portion; and an expandable / contractable portion fixed to a distal portion of the second tubular portion, wherein a first portion which is a part of the expandable / contractable portion is located in the inner cavity of the first shaft, and the expandable / contractable portion a second portion, which is located distal to the first portion, located outside the first shaft, the maximum outer diameter of the second portion being larger than the maximum outer diameter of the first tubular portion, the first portion being inscribed within the first shaft, and the outer diameter at the distal end of the bag-like body portion being larger than the maximum outer diameter of the first tubular portion, wherein, when the expandable / contractable portion is not positioned in the lumen of the distal end of the bag-like body portion, the minimum inner diameter of the bag-like body portion when it is pressurized by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-like body portion when it is not pressurized by injecting a fluid into the flow path.

[0394] The overall configuration of the fourth embodiment will be described with reference to Figures 56 to 72. These figures show a catheter 100 having a first shaft 1 equipped with a first tubular portion 10, a bag-shaped portion 20, and a flow path 40, and a second shaft 2 disposed in the lumen of the first shaft 1. In these figures, the longitudinal direction of the first tubular portion 10 is indicated by x, and the radial direction is indicated by y.

[0395] FIG. 56 is an enlarged cross-sectional view (partial side view) of a distal portion of a catheter according to an embodiment of the present invention, illustrating a state in which pressurization by injection of fluid into the flow path is not being performed. FIG. 57 is a cross-sectional view of the catheter shown in FIG. 56 taken along line LVII-LVII. FIG. 58 is a cross-sectional view (partial side view) of the catheter shown in FIG. 56 when pressurized by injection of fluid into the flow path. FIG. 59 is a cross-sectional view (partial side view) of the catheter shown in FIG. 56 when pressurized by injection of fluid into the flow path. FIG. 60 is a side view showing an example of a first shaft included in a catheter according to an embodiment of the present invention. FIG. 61 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 60. FIG. 62 is a cross-sectional view of the first shaft shown in FIG. 61 taken along line LXII-LXII. FIG. 63 is an enlarged cross-sectional view of a distal portion of the first shaft shown in FIG. 61 when pressurization by injection of fluid into the flow path is not being performed. Fig. 64 is a cross-sectional view of the first shaft shown in Fig. 63 when it is pressurized by injection of fluid into the flow channel. Fig. 65 is a cross-sectional view of the first shaft shown in Fig. 63 taken along line LXV-LXV. Fig. 66 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 63. Fig. 67 is a cross-sectional view of the first shaft shown in Fig. 66 taken along line LXVII-LXVII. Fig. 68 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 63. Fig. 69 is a cross-sectional view of the first shaft shown in Fig. 68 taken along line LXIX-LXIX. Fig. 70 is a cross-sectional view showing a modified example of the first shaft shown in Fig. 63. Fig. 71 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Fig. 59. Fig. 72 is a cross-sectional view (partially a side view) showing a modified example of the catheter shown in Fig. 59.

[0396] As shown in FIGS. 56 to 59, the catheter 100 has a first shaft 1 and a second shaft 2.

[0397] The first shaft 1 includes a first cylindrical portion 10 , a bag-shaped portion 20 , and a flow path 40 .

[0398] As shown in FIGS. 56 to 59, the first shaft 1 has a longitudinal direction and an inner cavity extending in the longitudinal direction.

[0399] 56 to 59 , the first shaft 1 has a first tubular portion 10 extending in the longitudinal direction of the first shaft 1. The first tubular portion 10 has a longitudinal direction x and a radial direction y that is perpendicular to the longitudinal direction x. The first tubular portion 10 preferably has an inner cavity 11 extending in the longitudinal direction x of the first tubular portion 10.

[0400] As shown in Figures 56, 58, and 59, the bag-like body portion 20 is a portion having a bag-like shape. Because the bag-like body portion 20 is bag-shaped, it is preferable that it has an internal space 23 therein. Furthermore, the bag-like body portion 20 is a portion formed in an annular shape. It is preferable that the bag-like body portion 20 has an inner cavity 25 formed therein by being formed in an annular shape. The bag-like body portion 20 is located distal to the first tubular portion 10.

[0401] As shown in FIGS. 56, 58 and 59, the distal end of the bag-shaped body portion 20 is provided with an X-ray opaque portion 3.

[0402] As shown in FIGS. 56 to 59, the flow path 40 has a space that allows fluid to be injected up to the bag-shaped body portion 20.

[0403] The inner cavity of the first shaft 1 is preferably configured by the inner cavity 11 of the first tubular portion 10 and the inner cavity 25 of the bag-like body portion 20 communicating with each other.

[0404] The second shaft 2 includes a second cylindrical portion 50 and an expanded / contracted diameter portion 60 , and is disposed in the inner cavity of the first shaft 1 .

[0405] The second cylindrical portion 50 preferably extends in the longitudinal direction of the first shaft 1. The second cylindrical portion 50 preferably has an inner cavity extending in the longitudinal direction of the first shaft 1.

[0406] The expandable / contractable section 60 is a section that can expand and contract in diameter, and is fixed to the distal part of the second tubular section 50 .

[0407] 59 , a first portion 61, which is a part of the expandable / contractable section 60, is located in the lumen of the first shaft 1, and a second portion 62, which is a portion of the expandable / contractable section 60 located distal to the first portion 61, is located outside the first shaft 1. Furthermore, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular section 10, and the first portion 61 is inscribed within the first shaft 1. With the above configuration, the length of the expandable / contractable section 60 that contacts the treatment area can be easily adjusted to a desired length.

[0408] 59 , the outer diameter at the distal end of the bag-shaped body portion 20 is larger than the maximum outer diameter of the first tubular portion 10, and an X-ray opaque portion 3 is provided at the distal end of the bag-shaped body portion 20. This makes it easier to visualize the proximal end of the expandable diameter portion 60 that comes into contact with the treatment site.

[0409] 56 and 58 , when the diameter-expanding section 60 is not disposed in the lumen 25 at the distal end of the bag-shaped body section 20, the minimum inner diameter of the bag-shaped body section 20 when the bag-shaped body section 20 is pressurized by injecting fluid into the flow path 40 is configured to be larger than the minimum inner diameter of the bag-shaped body section 20 when no pressurization is performed by injecting fluid into the flow path 40. This increases the minimum inner diameter of the bag-shaped body section 20 when it is pressurized.

[0410] The catheter 100 can be used, for example, by inserting the distal end of the first shaft 1 to a treatment site, and then protruding a portion of the expandable / contractable section 60 disposed in the lumen of the first shaft 1 from the first shaft 1. When transporting the first shaft 1 to the treatment site, as shown in FIG. 56 , the first shaft 1 is not pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-like body portion 20 is smaller than the minimum inner diameter of the bag-like body portion 20 when the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40. This makes it easier to reduce the outer diameter of the bag-like body portion 20. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. After transporting the first shaft 1 to the treatment site, as shown in FIG. 58 , the bag-like body portion 20 is pressurized by injecting a fluid into the flow path 40. In this state, the minimum inner diameter of the bag-shaped body portion 20 is larger than the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injection of fluid into the flow path 40 has not been performed. This makes it easier to protrude a portion of the expandable / contractable portion 60 from the expanded-diameter bag-shaped body portion 20. After the bag-shaped body portion 20 is pressurized by injection of fluid into the flow path 40, as shown in Fig. 59, the first portion 61 is located in the lumen of the first shaft 1, the second portion 62 is located outside the first shaft 1, the maximum outer diameter of the second portion 62 is larger than the maximum outer diameter of the first tubular portion 10, and the first portion 61 is inscribed within the first shaft 1. This makes it easier to adjust the length of the expandable / contractable portion 60 that contacts the treatment site to a desired length. In addition, the outer diameter at the distal end of the bag-shaped body portion 20 is larger than the maximum outer diameter of the first tubular portion 10, and an X-ray opaque portion 3 is provided at the distal end of the bag-shaped body portion 20, making it easier to visualize the proximal end of the expansion / contraction portion 60 that abuts the treatment area.

[0411] The first cylindrical portion 10 preferably has a distal end 10 a and a proximal end 10 b. The first cylindrical portion 10 also preferably has an inner surface 10 c facing the lumen 11 of the first cylindrical portion 10 and an outer surface 10 d facing the outside of the first cylindrical portion 10.

[0412] The outer surface 10d of the first cylindrical portion 10 is preferably coated with a hydrophilic polymer, which makes it easier to insert the first cylindrical portion 10 into a body cavity. Examples of hydrophilic polymers include poly (2-hydroxyethyl methacrylate), polyacrylamide, polyvinylpyrrolidone, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers, and polyethylene glycol.

[0413] The inner surface 10c of the first tubular portion 10 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin, or the entire inner surface 10c of the first tubular portion 10 may be made of a fluororesin or a polyolefin resin. This makes the first tubular portion 10 more easily slippery relative to components placed in the lumen 11 of the first tubular portion 10, thereby making it easier to improve the operability of the catheter 100.

[0414] As shown in Figure 61, the first tubular portion 10 may have a distal opening 11a at a distal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10, and may have a proximal opening 11b at a proximal portion of the first tubular portion 10 that connects the inner cavity 11 of the first tubular portion 10 to the outside of the first tubular portion 10.

[0415] As shown in Figures 60 and 61, the first tubular portion 10 can be configured to have a tapered region 13 in the proximal portion of the first tubular portion 10, whose length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x of the first tubular portion 10 decreases toward the proximal side.

[0416] 61 , it is preferable that a proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in the tapered region 13. It is more preferable that the proximal opening 11b that communicates between the lumen 11 of the first tubular portion 10 and the outside of the first tubular portion 10 is formed in a portion that slopes so that the length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x decreases toward the proximal side. With this configuration, for example, the guidewire 4 or the second shaft 2 can be inserted into and removed from the lumen 11 of the first tubular portion 10 through the proximal opening 11b.

[0417] 60 and 61 , the first shaft 1 may further include a third tubular portion 70. A distal portion of the third tubular portion 70 is fixed to a proximal portion of the reduced diameter region 13, and a lumen 71 of the third tubular portion 70 and the flow path 40 can be configured to communicate with each other.

[0418] The third cylindrical portion 70 is a cylindrical portion having an inner cavity 71. It is preferable that the maximum outer diameter of the third cylindrical portion 70 is smaller than the maximum outer diameter of the first cylindrical portion 10. Furthermore, the minimum outer diameter of the third cylindrical portion 70 may be smaller than the minimum outer diameter of the first cylindrical portion 10.

[0419] For the configuration of the third cylindrical portion 70, such as the material constituting the third cylindrical portion 70, reference can be made to the description of the first cylindrical portion 10. The material constituting the third cylindrical portion 70 and the material constituting the first cylindrical portion 10 may be the same or different.

[0420] It is preferable that a lubricating coating layer containing PTFE, PFA, or the like is formed on the outer surface of the third cylindrical portion 70. This makes it easier to insert the third cylindrical portion 70 into a body cavity.

[0421] The third cylindrical portion 70 may be provided with a position indication marker for indicating the length of the inserted portion when the first shaft 1 is inserted into a body cavity. The position indication marker may be formed, for example, by inserting the third cylindrical portion 70 into the inner cavity of a marker tube and welding it, or may be formed by peeling off a part of the lubricating coating layer containing the above-mentioned PTFE, PFA, or the like.

[0422] The position indication markers can be provided, for example, at positions 600 mm, 900 mm, 1200 mm, etc. from the distal end of the first shaft 1.

[0423] It is preferable that the distal portion of the third tubular portion 70 and the proximal portion of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is more preferable that the distal end of the third tubular portion 70 and the proximal end of the tapered region 13 are fixed together so that the lumen 71 of the third tubular portion 70 and the flow path 40 are in communication with each other. It is preferable that the lumen 71 of the third tubular portion 70 does not communicate with the lumen 11 of the first tubular portion 10.

[0424] 60 , the catheter 100 preferably further includes a hub 72 connected to the proximal end of the first shaft 1. The hub 72 may be connected to the third cylindrical portion 70. In this case, the hub 72 preferably includes a port therein that communicates with the lumen 71 of the third cylindrical portion 70, and a fluid can be injected into the lumen 71 of the third cylindrical portion 70 via the port.

[0425] Although not shown, the first shaft 1 may not include the third cylindrical portion 70, and the proximal end 10b of the first cylindrical portion 10 may be directly connected to the hub 72. In this case, it is preferable that the hub 72 has a port therein that communicates with the flow path 40, and that a fluid can be injected into the flow path 40 via the port.

[0426] The material constituting the bag-shaped body portion 20 can be, for example, any of the materials listed as being constituting the first tubular portion 10. The material constituting the bag-shaped body portion 20 and the material constituting the first tubular portion 10 may be the same or different.

[0427] As shown in Figures 60 and 61, the proximal portion of the bag-shaped body portion 20 may be connected to the distal portion of the first tubular portion 10, or the proximal end of the bag-shaped body portion 20 may be connected to the distal end 10a of the first tubular portion 10.

[0428] The minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. In particular, as shown in FIG. 63 , when pressurization by injecting a fluid into the flow path 40 is not performed, the minimum outer diameter of the bag-shaped body portion 20 is preferably smaller than the outer diameter of the first tubular portion 10. This makes it less likely that the first shaft 1 will get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. From the viewpoint of enhancing this effect, as shown in FIG. 63 , when pressurization by injecting a fluid into the flow path 40 is not performed, the maximum outer diameter of the bag-shaped body portion 20 is more preferably equal to or smaller than the outer diameter of the first tubular portion 10. Note that, as shown in FIG. 64 , even when the bag-shaped body portion 20 is pressurized by injecting a fluid into the flow path 40, the minimum outer diameter of the bag-shaped body portion 20 may be smaller than the outer diameter of the first tubular portion 10. As shown in Figure 59, when the expandable diameter portion 60 is placed in the inner cavity 25 of the bag-shaped body portion 20 and the expandable diameter portion 60 expands, the maximum outer diameter of the bag-shaped body portion 20 may be greater than or equal to the outer diameter of the first tubular portion 10.

[0429] The bag-shaped body portion 20 provided distal to the distal end 10a of the first tubular portion 10 preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 63 , when pressurization by injecting a fluid into the flow path 40 is not performed, the bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. As shown in FIG. 63 , when pressurization by injecting a fluid into the flow path 40 is not performed, the entire bag-shaped body portion 20 more preferably has a tapered portion whose outer diameter decreases toward the distal side. This makes it less likely for the first shaft 1 to get caught on the wall of the body cavity when transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity. Note that, as shown in FIG. 64 , when pressurization by injecting a fluid into the flow path 40 is performed, the bag-shaped body portion 20 may have a tapered portion whose outer diameter decreases toward the distal side. 64, the entire bag-shaped body portion 20 may have a tapered portion with an outer diameter that decreases toward the distal side when the bag-shaped body portion 20 is pressurized by injecting a fluid into the flow path 40. As shown in Fig. 59, when the expandable / contractable diameter portion 60 is disposed in the lumen 25 of the bag-shaped body portion 20 and the expandable / contractable diameter portion 60 expands in diameter, the bag-shaped body portion 20 may have a tapered portion with an outer diameter that decreases toward the proximal side, or the entire bag-shaped body portion 20 may have a tapered portion with an outer diameter that decreases toward the proximal side.

[0430] Although the bag-shaped body portion 20 is formed in an annular shape, it may also have a hollow truncated cone shape, as shown in Figures 60 to 62. Although not shown, the bag-shaped body portion 20 may also have a hollow truncated polygonal pyramid shape, or a shape that combines a hollow truncated cone and a hollow truncated polygonal pyramid, for example, a shape in which a hollow truncated cone and a hollow truncated polygonal pyramid are connected in the longitudinal direction x of the first tubular portion 10.

[0431] When the expandable / contractable section 60 is not disposed in the lumen 25 at the distal end of the bag-shaped body section 20, the minimum inner diameter of the bag-shaped body section 20 when the bag-shaped body section 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 is preferably larger than the minimum inner diameter of the bag-shaped body section 20 when no pressurization is performed by injecting a fluid into the flow path 40. This increases the minimum inner diameter of the bag-shaped body section 20 when it is pressurized to a predetermined pressure or higher.

[0432] 61 to 64, the bag-shaped body portion 20 can be configured to have an inner surface portion 21 facing the lumen 25 of the bag-shaped body portion 20, and an outer surface portion 22 facing the outside of the bag-shaped body portion 20. The inner surface portion 21 has an inner surface facing the lumen 25, and the outer surface portion 22 has an outer surface facing the outside. The inner surface portion 21 has a distal end 21a and a proximal end 21b. The outer surface portion 22 has a distal end 22a and a proximal end 22b. It is preferable that an internal space 23 exists between the inner surface portion 21 and the outer surface portion 22.

[0433] It is preferable that the elongation percentage (%) of the length from the distal end 21 a to the proximal end 21 b of the inner surface portion 21 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 is greater than the elongation percentage (%) of the length from the distal end 22 a to the proximal end 22 b of the outer surface portion 22 when the bag-shaped body portion 20 changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 40 to a state in which the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40. With the above-described configuration, when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid, the inner surface portion 21, which is more elongate than the outer surface portion 22, stretches, and the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. This allows the minimum inner diameter of the bag-shaped body portion 20 when it is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 to be larger than the minimum inner diameter of the bag-shaped body portion 20 when it is not pressurized by injecting a fluid into the flow path 40. In the example described above, the first shaft 1 is more likely to change from the state shown in FIG. 63 to the state shown in FIG. 64. Therefore, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site, it is possible to make the second shaft 2 easily protrude from the expanded diameter portion. The elongation rate (%) is calculated by dividing the length of each portion after pressurization by the length of each portion before pressurization.

[0434] The inner surface portion 21 and the outer surface portion 22 may be made of the same material or different materials.

[0435] When the inner surface portion 21 and the outer surface portion 22 are made of the same material, for example, it is preferable that the thickness of the inner surface portion 21 is thinner than the thickness of the outer surface portion 22. This makes the inner surface portion 21 more stretchable than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to become larger than before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in Fig. 63 to the state shown in Fig. 64. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0436] When the inner surface portion 21 and the outer surface portion 22 are made of different materials, for example, it is preferable that the elongation rate of the material making up the inner surface portion 21 be higher than that of the material making up the outer surface portion 22. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material making up the inner surface portion 21 and a sample made of the material making up the outer surface portion 22, formed to the same shape as the sample, are prepared, and then the samples are gripped at one end and the other end so that the grip width is the same length and pulled with the same strength (N). This makes the inner surface portion 21 more elongate than the outer surface portion 22, and as the inner surface portion 21 of the bag-shaped body portion 20 stretches, the inner diameter of the bag-shaped body portion 20 tends to increase compared to before pressurization. In the example described above, the first shaft 1 tends to change from the state shown in FIG. 63 to the state shown in FIG. 64. This makes it easier for the second shaft 2 to protrude from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to the treatment site.

[0437] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, the angle α between the inner surface portion 21 and the outer surface portion 22 when pressurization by injecting a fluid into the flow path 40 is not performed is preferably an acute angle, as shown in FIG. 63 . The angle α may be 85° or less, 80° or less, or 70° or less. The angle α may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and improve passability through the body cavity.

[0438] In a cross section parallel to the longitudinal direction x of the first tubular portion 10, when the first tubular portion 10 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40, the angle β between the inner surface portion 21 and the outer surface portion 22 is preferably an acute angle, as shown in FIG. 64 . The angle β may be 85° or less, 80° or less, or 70° or less. The angle β may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the thickness of the distal end of the bag-shaped body portion 20. In other words, the length between the inner surface of the inner surface portion 21 and the outer surface of the outer surface portion 22 can be easily shortened. This makes it easier to increase the inner diameter of the distal end of the bag-shaped body portion 20 when the first tubular portion 10 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40. This makes it easier to protrude the second shaft 2 from the expanded diameter portion, even when the second shaft 2 is placed in the lumen of the first shaft 1 and transported to a treatment site.

[0439] As shown in Figures 61 and 62 , the internal space 23 is a space formed within the wall that constitutes the annular bag-shaped body portion 20. In the example shown in Figures 61 and 62 , the internal space 23 is a space that exists within the wall that forms the lumen 25 of the bag-shaped body portion 20. As shown in Figures 61 and 62 , the internal space 23 preferably exists throughout the entire circumferential direction within the wall of the bag-shaped body portion 20. In other words, the internal space 23 is preferably a space that is circumferentially connected within the wall of the bag-shaped body portion 20. Although not shown, the internal space 23 may exist only partially within the circumferential direction within the wall of the bag-shaped body portion 20.

[0440] It is preferable that the internal space 23 does not communicate with the lumen 11 of the first tubular portion 10. It is also preferable that the internal space 23 does not communicate with the lumen 25 of the bag-shaped body portion 20. This makes it easier for the fluid injected into the flow path 40 to efficiently flow into the internal space 23 formed in the bag-shaped body portion 20.

[0441] 63 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when no pressurization is being performed by injecting a fluid into the flow path 40, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0442] 64 , when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injection of a fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 preferably decreases from the proximal end to the distal end of the internal space 23 of the bag-shaped body portion 20. This makes it easier to reduce the outer diameter of the distal end of the bag-shaped body portion 20. Therefore, when the minimum internal diameter of the bag-shaped body portion 20 increases due to pressurization to a predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0443] 63 , in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10 when no pressurization is being performed by injecting a fluid into the flow path 40, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, the first shaft 1 is less likely to get caught on the wall of the body cavity when being transported to the treatment site, making it easier to prevent damage to the wall of the body cavity and to improve passability through the body cavity.

[0444] 64 , when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injection of a fluid into the flow path 40, in a cross section passing through the central axis of the first tubular portion 10 and taken along the longitudinal direction x of the first tubular portion 10, the length of the internal space 23 of the bag-shaped body portion 20 in the radial direction y of the first tubular portion 10 is preferably equal to or less than the length of the flow path 40 in the radial direction y of the first tubular portion 10. This makes it easier to reduce the outer diameter of the bag-shaped body portion 20. Therefore, when the minimum inner diameter of the bag-shaped body portion 20 increases due to pressurization to a predetermined pressure or higher, it is easier to prevent the bag-shaped body portion 20 from unintentionally contacting the wall of the body cavity.

[0445] The length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when no pressurization is performed by injecting a fluid into the flow path 40 and the length of the bag-shaped body portion 20 in the longitudinal direction x of the first tubular portion 10 when the bag-shaped body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 may be the same or different.

[0446] The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0447] The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-like body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-like body portion 20 in the longitudinal direction x of the first cylindrical portion 10 when the bag-like body portion 20 is pressurized to a predetermined pressure or higher by injecting a fluid into the flow path 40 can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0448] The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed is preferably a size that allows the guide wire 4 to be inserted therethrough. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 30% or more, 35% or more, or 40% or more of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be 70% or less, 65% or less, or 60% or less of the inner diameter of the first tubular portion 10. The minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc. Furthermore, the minimum inner diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed may be, for example, 2.00 mm or less, 1.95 mm or less, 1.90 mm or less, etc.

[0449] 63 , in a state where pressurization by injection of a fluid into the flow path 40 is not performed, the inner diameter of the bag-shaped body portion 20 is preferably smallest at the distal end of the bag-shaped body portion 20. In a state where pressurization at a predetermined pressure or higher by injection of a fluid into the flow path 40 is performed, the inner diameter of the bag-shaped body portion 20 may be smallest at the proximal end or the distal end of the bag-shaped body portion 20.

[0450] The minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 0.31 mm or more, 0.36 mm or more, 0.41 mm or more, etc. Furthermore, the minimum outer diameter of the bag-shaped body portion 20 in a state where pressurization by injecting a fluid into the flow path 40 is not performed can be, for example, 3.00 mm or less, 2.90 mm or less, 2.80 mm or less, etc.

[0451] As shown in Fig. 63, in a state where no pressurization is performed by injecting a fluid into the flow path 40, it is preferable that the distal end of the bag-shaped body portion 20 has the smallest outer diameter. As shown in Fig. 64, in a state where pressuri...

Claims

1. A catheter comprising: a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising: a first tubular portion extending in the longitudinal direction, a pouch portion located distal to the first tubular portion and formed in an annular shape, and a flow path having a space capable of injecting a fluid up to the pouch portion; and a second shaft comprising: a second tubular portion and an expanding / contracting portion fixed to a distal portion of the second tubular portion, wherein a first portion which is a part of the expanding / contracting portion is located in the inner cavity of the first shaft, a second portion which is a portion of the expanding / contracting portion located distal to the first portion is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, and the outer surface of the first portion is inscribed in the first shaft, A catheter in which, when the expandable / contractable portion is not positioned in the inner cavity of the distal end of the bag-shaped body portion and the bag-shaped body portion is pressurized by injecting fluid into the flow path, the minimum inner diameter of the bag-shaped body portion is larger than the minimum inner diameter of the bag-shaped body portion when it is not pressurized by injecting fluid into the flow path.

2. A catheter as described in claim 1, wherein when the expandable / contractable portion is not positioned in the lumen of the distal end of the bag-like body portion and the bag-like body portion is pressurized to a predetermined pressure or more by injecting fluid into the flow path, the minimum inner diameter of the bag-like body portion is greater than the minimum inner diameter of the bag-like body portion when it is not pressurized by injecting fluid into the flow path.

3. A catheter as described in claim 1 or 2, wherein when no pressure is applied by injecting a fluid into the flow path, the first tubular portion has a protrusion that protrudes radially inward from the first tubular portion.

4. A catheter as claimed in claim 1 or 2, further comprising a reinforcing member disposed between said flow path and the inner lumen of said first tubular portion.

5. The catheter according to claim 4, wherein the reinforcing member is made of metal, and the reinforcing member is made of a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof.

6. A catheter as described in claim 1 or 2, wherein when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the maximum inner diameter of the bag-shaped portion is larger than the maximum inner diameter of the first tubular portion.

7. A catheter as described in claim 1, wherein the first shaft has a bulge portion that bulges radially inward from the first tubular portion, the flow path has a space into which fluid can be injected up to the bulge portion, and the bulge portion bulges and bulges radially inward from the first tubular portion when the bulge portion is pressurized by injection of fluid into the flow path.

8. A catheter as described in claim 7, wherein the bulging portion swells and bulges radially inwardly of the first tubular portion when the bag-like body portion is pressurized to a first predetermined pressure or higher by injection of fluid into the flow path, and when the expandable / contractable portion is not positioned in the inner cavity of the distal end of the bag-like body portion, the minimum inner diameter of the bag-like body portion when the bag-like body portion is pressurized to a second predetermined pressure or higher by injection of fluid into the flow path is greater than the minimum inner diameter of the bag-like body portion when it is not pressurized by injection of fluid into the flow path.

9. The catheter of claim 8, wherein said second predetermined pressure is less than said first predetermined pressure.

10. A catheter as described in claim 8 or 9, wherein when the flow path is pressurized to a pressure equal to or greater than the first predetermined pressure by injection of fluid into the flow path, the surface of the bulge portion located radially inward of the first tubular portion abuts against the expansion / contraction portion.

11. A catheter as described in claim 8 or 9, wherein when the flow path is pressurized to a pressure equal to or greater than the first predetermined pressure by injection of fluid into the flow path, the inner cavity of the first tubular portion is blocked by the expanded bulge portion or the expandable / contractable portion.

12. A catheter as described in claim 8 or 9, wherein when the second shaft is not positioned distal to the proximal end of the bulge portion and the bulge portion is pressurized to a pressure equal to or greater than the first specified pressure by injecting fluid into the flow path, a first surface portion that is a part of the surface of the bulge portion located radially inward of the first tubular portion abuts a second surface portion that is a part of the surface of the bulge portion located radially inward of the first tubular portion and is different from the first surface portion.

13. A catheter as described in claim 8 or 9, wherein when the second shaft is not positioned distal to the proximal end of the bulge portion and the flow path is pressurized to a pressure equal to or greater than the first predetermined pressure by injection of fluid into the flow path, the inner cavity of the first tubular portion is blocked by the bulged portion.

14. A catheter as described in claim 1, wherein the first shaft has a bulge portion that bulges radially outward from the first tubular portion, the flow path has a space capable of injecting fluid up to the bulge portion, and the bulge portion bulges and bulges radially outward from the first tubular portion when the bulge portion is pressurized by injecting fluid into the flow path.

15. A catheter as described in claim 14, wherein the bulging portion swells and bulges radially outwardly of the first tubular portion when the bag-like body portion is pressurized to a third predetermined pressure or higher by injection of fluid into the flow path, and when the expandable / contractable portion is not positioned in the inner cavity of the distal end of the bag-like body portion, the minimum inner diameter of the bag-like body portion when the bag-like body portion is pressurized to a fourth predetermined pressure or higher by injection of fluid into the flow path is greater than the minimum inner diameter of the bag-like body portion in a state where it is not pressurized by injection of fluid into the flow path.

16. The catheter of claim 15, wherein said fourth predetermined pressure is greater than or equal to said third predetermined pressure.

17. A catheter as described in any one of claims 14 to 16, wherein the bulging height of the bulging portion in the radial direction of the first tubular portion varies in the circumferential direction of the first tubular portion.

18. The catheter according to claim 1, wherein the distal end of the bag-shaped body portion is provided with an X-ray opaque portion, and the outer diameter at the distal end of the bag-shaped body portion is larger than the maximum outer diameter of the first tubular portion.

19. A catheter as described in claim 18, wherein when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer diameter at the distal end of the bag-shaped portion is within ±3 mm of the maximum outer diameter of the second portion.

20. A catheter comprising: a first shaft having a longitudinal direction and an inner cavity extending in the longitudinal direction, the first shaft comprising a first tubular portion extending in the longitudinal direction, a bag-like body portion located distal to the first tubular portion and formed in an annular shape, and a flow path having a space through which a fluid having radiopacity can be injected up to the bag-like body portion; and a second shaft comprising a second tubular portion and an expanding / contracting diameter portion fixed to a distal portion of the second tubular portion and disposed in the inner cavity of the first shaft, wherein a first portion that is a part of the expanding / contracting diameter portion is located in the inner cavity of the first shaft, a second portion that is a portion of the expanding / contracting diameter portion located distal to the first portion is located outside the first shaft, the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the first portion is inscribed in the first shaft, and the outer diameter at the distal end of the bag-like body portion is larger than the maximum outer diameter of the first tubular portion.

21. A catheter as described in claim 20, wherein when no pressure is applied by injecting a fluid into the flow path, the first tubular portion has a protrusion that protrudes radially inward from the first tubular portion.

22. The catheter according to claim 20 or 21, wherein a reinforcing member is disposed between the flow path and the lumen of the first cylindrical portion.

23. The catheter of claim 22, wherein the reinforcing member is made of metal, and the reinforcing member is made of a tube, a braid in which wire is woven, a coil in which wire is wound, or a combination thereof.

24. A catheter as described in claim 20 or 21, wherein when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the maximum inner diameter of the bag-shaped portion is larger than the maximum inner diameter of the first tubular portion.

25. A catheter as described in claim 20 or 21, wherein when the maximum outer diameter of the second portion is larger than the maximum outer diameter of the first tubular portion, the outer diameter at the distal end of the bag-shaped portion is within ±3 mm of the maximum outer diameter of the second portion.

26. A catheter as described in claim 20 or 21, wherein when the expandable / contractable portion is not disposed in the lumen of the distal end of the bag-like body portion and the bag-like body portion is pressurized by injecting fluid into the flow path, the minimum inner diameter of the bag-like body portion is greater than the minimum inner diameter of the bag-like body portion when it is not pressurized by injecting fluid into the flow path.

27. A catheter as described in claim 26, wherein when the expandable / contractable portion is not disposed in the lumen of the distal end of the bag-like body portion and the bag-like body portion is pressurized to a predetermined pressure or more by injection of fluid into the flow path, the minimum inner diameter of the bag-like body portion is larger than the minimum inner diameter of the bag-like body portion when it is not pressurized by injection of fluid into the flow path.

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