catheter

Abstract

The present invention provides a catheter that facilitates the deployment of a balloon at the target location in the bile duct. [Solution] A catheter 10, the tip of which is inserted into the bile duct 6, comprises a catheter body 11 extending in the axial direction, a tip balloon 12 positioned on the tip side of the catheter body 11 and capable of maintaining a predetermined radial length D1 when pressure exceeding a predetermined inflation pressure is applied, and a proximal balloon 13 positioned adjacent to the proximal end of the tip balloon 11 on the catheter body 11 and capable of gradually expanding in response to an increase in inflation pressure. The radial length D2 of the proximal balloon 13 in the deployed state is greater than the radial length D1 of the tip balloon 12 in the deployed state, and the proximal balloon 13 forms a locking portion on the outside of the bile duct 6 when deployed.

Description

Technical Field

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[0001] The present invention relates to a catheter whose tip is inserted into the bile duct.

Background Art

[0002] For example, a technique is known in which a catheter is inserted from the duodenum into the bile duct using an endoscope to perform cholangiography, collection of biological tissue in the bile duct, removal of gallstones, etc. When it is necessary to expand the bile duct during such a technique, a catheter having a balloon that expands within the biological lumen can be applied.

[0003] <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ One aspect of the present invention is a catheter, the tip of which is inserted into the bile duct, comprising: a catheter body extending in the axial direction; a tip balloon positioned on the tip side of the catheter body and capable of maintaining a predetermined radial length when pressure exceeding a predetermined inflation pressure is applied; and a proximal balloon positioned adjacent to the proximal end of the tip balloon on the catheter body and capable of gradually expanding in response to an increase in inflation pressure. The radial length of the proximal balloon in the deployed state is greater than the radial length of the tip balloon in the deployed state, and the proximal balloon, when deployed, forms a locking portion on the outside of the bile duct. [Effects of the Invention]

[0008] According to one aspect of the present invention, a catheter can be provided that facilitates the deployment of a balloon at a target location in the bile duct. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing an example of an endoscopic procedure using the catheter of this embodiment. [Figure 2] This figure shows an example of the catheter configuration of this embodiment. [Figure 3] (a) is a diagram showing a cross-section of the catheter body along the axial direction, and (b) is a diagram showing a cross-section of the catheter body perpendicular to the axial direction. [Figure 4] This is an enlarged view showing the proximal end of the deployed tip balloon and the tip of the deployed proximal balloon. [Figure 5] Figures (a) to (c) show examples of the attachment state of the proximal end of the tip balloon and the tip end of the proximal balloon. [Figure 6] This figure shows a modified version of the catheter body. [Figure 7] This figure shows other variations of the catheter body. [Modes for carrying out the invention]

[0010] The following describes an example of the catheter configuration according to the embodiment, with reference to the drawings. Note that the shapes and dimensions of each part in the drawings are schematic and do not represent the actual shapes and dimensions.

[0011] Figures 1(a) to 1(c) are schematic diagrams showing an example of an endoscopic procedure using the catheter of this embodiment. In the following description, the end furthest from the operator of the procedure will be referred to as the proximal end, and the end closer to the operator will be referred to as the proximal end.

[0012] As shown in Figures 1(a) to 1(c), the catheter 10 of this embodiment is introduced into the patient's body via a duodenal endoscope 1 during the procedure. Here, the duodenal endoscope 1 has a long tubular insertion section 2 that is inserted into the patient's biological lumen and is operated by an operator from the proximal end.

[0013] The tubular insertion section 2 has multiple lumens (not shown) that communicate from the proximal end to the distal end of the tubular insertion section 2 along its long axis. Each lumen of the tubular insertion section 2 is used, for example, as a forceps channel for inserting various treatment instruments including the catheter 10 or a guide wire, a suction channel for aspirating liquid toward the proximal end of the tubular insertion section 2, or a channel for inserting a cable for an imaging unit or illumination unit provided at the distal end of the tubular insertion section 2. One lumen may be used for multiple purposes.

[0014] As shown in Figures 1(a) to 1(c), the tip end of the tubular insertion section 2 is positioned near the papilla 5 of the duodenum 4 during the procedure. The tip end of the tubular insertion section 2 is equipped with an objective lens (not shown) for the imaging unit, an illumination unit (not shown), and a forceps channel. The duodenal endoscope 1 can image the inside of the biological lumen with the imaging unit via the objective lens and display the image of the biological lumen in real time on a display device (not shown). The illumination unit can illuminate the inside of the biological lumen with light guided from a light source, for example, by an optical fiber. The forceps channel is provided for inserting and removing various instruments, including the catheter 10, and for taking biological tissue with the instruments, and is in communication with the lumen of the forceps channel of the tubular insertion section 2.

[0015] The catheter 10 is inserted into the lumen (forceps channel) of the tubular insertion portion 2 in a nested manner from the proximal end side. As shown in each figure of FIG. 1, the tip side portion of the catheter 10 protrudes from the forceps opening of the tubular insertion portion 2 during the procedure and is exposed into the duodenum 4. The tip side portion of the catheter 10 protruding from the tubular insertion portion 2 is inserted into the common bile duct 6.

[0016] FIG. 2 is a diagram showing a configuration example of the catheter 10 of the present embodiment. FIG. 3(a) is a diagram showing a cross section along the axial direction of the catheter body, and FIG. 3(b) is a diagram showing a cross section orthogonal to the axial direction of the catheter body. In the drawings, the axial direction Ax of the catheter is appropriately indicated by an arrow. Also, a direction substantially orthogonal to the axial direction Ax is defined as the radial direction, and a rotational direction centered on the axial direction Ax is defined as the circumferential direction.

[0017] As shown in FIG. 2, the catheter 10 includes a catheter body 11, a tip side balloon 12, a proximal end side balloon 13, a first marker 14, and a second marker 15. Before balloon deployment, the catheter 10 may be housed in a cylindrical sheath (not shown) and introduced into the body, and the tip side portion may be released from the sheath before balloon deployment.

[0018] The catheter body 11 is a flexible, elongated tubular body extending in the axial direction. The outer diameter of the catheter body 11 is formed smaller than the inner diameter of the lumen of the tubular insertion portion 2. Thereby, the catheter body 11 can be inserted into and removed from the lumen of the tubular insertion portion 2.

[0019] The catheter body 11 is formed into a tubular shape having a substantially uniform thickness in the circumferential direction by a biocompatible material. Inside the catheter body 11, a main lumen 21 and two diluent lumens 22a, 22b are formed along the axial direction, respectively.

[0020] The main lumen 21 is formed in the axial center of the catheter body 11 and is a gap that penetrates the catheter body 11 in the axial direction. The main lumen 21 is used, for example, as a channel for inserting other instruments or as a channel for flowing medication or contrast agents.

[0021] Each of the expansion fluid lumens 22a and 22b is smaller in diameter than the main lumen 21 and is a gap extending axially from the proximal end of the catheter body 11. Each of the expansion fluid lumens 22a and 22b is located on the outer circumference of the main lumen 21 and is positioned at a predetermined interval in the circumferential direction of the catheter body 11. For example, in Figure 3, two expansion fluid lumens 22a and 22b are positioned circumferentially around the main lumen 21 at a 180-degree interval. Note that Figure 3(b) shows an example where the cross-sectional shape of the expansion fluid lumens 22a and 22b is circular, but the cross-sectional shape of the expansion fluid lumens 22a and 22b may be other shapes, such as elliptical or semicircular.

[0022] As shown in Figure 3(a), the tip end of one of the expansion fluid lumens 22a communicates with the outer circumference of the catheter body 11 in the attachment area of ​​the tip balloon 12. As a result, one of the expansion fluid lumens 22a functions as a channel for supplying expansion fluid from the proximal end of the catheter 10 to the tip balloon 12.

[0023] Furthermore, the tip end of the other expansion fluid lumen 22b communicates with the outer circumference of the catheter body 11 in the mounting area of ​​the proximal balloon 13, as shown in Figure 3(a). As a result, the other expansion fluid lumen 22b functions as a channel for supplying expansion fluid from the proximal end of the catheter 10 to the proximal balloon 13.

[0024] The main lumen 21 and the expansion fluid lumens 22a and 22b in the catheter body 11 can be formed, for example, by applying a resin solution to the core wires corresponding to each lumen to form the catheter body 11, and then pulling these core wires out from the catheter body 11.

[0025] Furthermore, a wide range of thermoplastic polymers can be used as the material for the catheter body 11. While not particularly limited, examples of materials that can be used for the catheter body 11 include polyimide (PI), polyamide-imide (PAI), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), nylon elastomer, polyurethane (PU), ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVA), or polypropylene (PP). In addition, inorganic fillers such as barium sulfate or bismuth subcarbonate may be mixed into the catheter body 11 to improve radiopaqueness.

[0026] Furthermore, although not particularly limited, a hydrophilic coating may be formed on the outer surface of the catheter body 11 using a material such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone.

[0027] Furthermore, the catheter body 11 may have a coating layer (inner layer) made of a biocompatible resin material on the outer circumference of the main lumen 21. Although not particularly limited, the inner layer may be made of fluorine-based thermoplastic polymer materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or perfluoroalkoxy fluoropolymer (PFA), as an example.

[0028] Furthermore, the catheter body 11 may have a reinforcing layer that houses the main lumen 21 on its inside and is tubular in shape along the axial direction. The reinforcing layer may be formed by winding wires such as metal wires or polymer fiber wires, or it may be formed by weaving the above wires into a mesh and tubular in shape.

[0029] Next, the tip balloon 12 and the proximal balloon 13 will be described. The distal balloon 12 and the proximal balloon 13 are balloons that can be inflated independently within the biological lumen. As shown in Figure 2, the distal balloon 12 and the proximal balloon 13 are arranged adjacent to each other in the axial direction at the distal portion of the catheter body 11.

[0030] Here, the statement that the tip balloon 12 and the proximal balloon 13 are adjacent in the axial direction includes both the configuration in which the tip balloon 12 and the proximal balloon 13 are adjacent to each other without any gap in the axial direction, and the configuration in which the tip balloon 12 and the proximal balloon 13 are separated by a gap in the axial direction. Preferably, the gap between the tip balloon 12 and the proximal balloon 13 before deployment is such that contact occurs between the tip balloon 12 and the proximal balloon 13 after each balloon is deployed, or that the tip balloon 12 and the proximal balloon 13 after deployment are slightly separated. For example, the axial length of the gap on the catheter body 11 may be such that, as shown in Figure 4 below, the amount by which the proximal balloon 13 protrudes toward the tip due to expansion after deployment is smaller, and the gap on the catheter body 11 is covered by the proximal balloon 13 after deployment. The balloon covering the gap on the catheter body 11 may be the tip balloon 12.

[0031] The distal balloon 12 is positioned distal to the proximal balloon 13 at the distal portion of the catheter body 11. When the distal balloon 12 is deployed by pressurization with the expansion fluid, it expands concentrically with the catheter body 11 when viewed from the axial direction, and plays the role of expanding the target position of the common bile duct 6 from the inside (see Figure 1(c)).

[0032] The tip balloon 12 expands to a predetermined radial length (diameter) D1 in response to an increase in expansion pressure until a predetermined expansion pressure is reached. When pressure exceeding the predetermined expansion pressure is applied, the balloon does not expand further and maintains the predetermined radial length D1. The tip balloon 12 is suitable for expanding constricted areas.

[0033] In its deployed state (the state after the balloon has expanded and unfolded), the tip balloon 12 has a cylindrical shape with an axial length longer than its radial length. For example, the tip balloon 12 may have a cross-sectional shape such as an oblong, elliptical, or hexagonal shape that is long in the axial direction and flattened in the radial direction. Figure 2 shows an example in which the tip balloon 12 is oblong.

[0034] The predetermined radial length D1 of the tip balloon 12 in the deployed state is defined within the range necessary for dilating the narrowed portion of the bile duct. While not particularly limited, the value of D1 is, for example, 3 mm to 25 mm.

[0035] However, in the case of the tip balloon 12, variations in the dimensions of the deployed state may occur from product to product due to factors such as the dimensional tolerance of the balloon itself, errors during balloon installation, and errors in the elongation of the membrane. Therefore, the predetermined radial length D1 is defined as a value that has a tolerance range set considering the above variations. In other words, the dimensions of the tip balloon 12 in the deployed state will satisfy the specification of the predetermined radial length D1 whether they are smaller or larger than D1, as long as they are within the tolerance range.

[0036] The axial length L1 of the tip balloon 12 is set to a length corresponding to the range of the target position, such that it is longer than the range of the target position (i.e., the axial length of the narrowed portion of the bile duct). While not particularly limited, the value of L1 is, for example, 20 mm to 50 mm.

[0037] The tip balloon 12 is, for example, composed of a non-compliant balloon. While not particularly limited, the tip balloon 12 may have a pressure resistance higher than, for example, 6 atmospheres.

[0038] For example, PET can be used as the material for the tip balloon 12, but the tip balloon 12 may be made of other materials.

[0039] Furthermore, the tip balloon 12 is made of a material that is transparent to the wavelength of the illumination light of the duodenal endoscope 1 in order to ensure the visibility of the first marker 14.

[0040] The proximal balloon 13 is positioned adjacent to the tip balloon 12 at the tip portion of the catheter body 11, on the proximal side. When the proximal balloon 13 is deployed by pressurization with the expansion fluid, it expands concentrically with the catheter body 11 when viewed from the axial direction. In the deployed state, the proximal balloon 13 has a shape in which the outer portion protrudes axially outward relative to the inner portion, and the inner portion is constricted axially inward.

[0041] Unlike the tip balloon 12, the proximal balloon 13 is a balloon that can gradually expand in response to an increase in expansion pressure. "Gradually expandable in response to an increase in expansion pressure" means that, within a range below the burst pressure of the proximal balloon 13, it continues to expand in such a way that its length in the direction intersecting the axial direction increases in response to the increase in expansion pressure. For example, the radial length of the proximal balloon 13, as the length in the direction intersecting the axial direction, may increase in an almost linear relationship with the increase in expansion pressure, or it may increase in a nonlinear relationship with the increase in expansion pressure.

[0042] The membrane of the proximal balloon 13 is made of a material with lower membrane rigidity than that of the tip balloon 12, and is more flexible and stretchable than the tip balloon 12. Furthermore, the flexibility and stretchability of the membrane of the proximal balloon 13 make it easier to suppress the profile during deflation compared to the tip balloon 12.

[0043] The proximal balloon 13 may be composed of, for example, a compliant balloon or a semi-compliant balloon. While not particularly limited, the pressure resistance of the proximal balloon 13 may be lower than that of the tip balloon 12, for example, 6 atmospheres or less.

[0044] Examples of materials for the proximal balloon 13 include urethane and nylon 12, but the proximal balloon 13 may be formed from other materials.

[0045] As shown in Figure 2, the radial length (diameter) D2 of the proximal balloon 13 in the deployed state is greater than the radial length D1 of the proximal balloon 12 in the deployed state (D2 > D1). For example, the value of D2 in the deployed state is the value used in the standard operating environment of the proximal balloon 13 as a specification. Therefore, the proximal balloon 13 is more radially inflated than the proximal balloon 12 in the deployed state. Also, the axial length L2 of the proximal balloon 13 is smaller than the axial length L1 of the proximal balloon 12 (L2 <L1)。

[0046] The proximal balloon 13, located on the proximal side of the distal balloon 12 and expanding radially more than the distal balloon 12, forms a locking portion on the outside of the common bile duct 6 when expanded, as shown in Figures 1(b) and (c). That is, when the proximal balloon 13 is expanded by the pressurization of the expansion fluid, at least a portion of its outer surface comes into contact with the outer part of the common bile duct 6. The proximal balloon 13 then locks into the locking portion on the biological lumen side, thereby restricting the axial movement of the catheter body 11 toward the distal end and playing a role in positioning the catheter body 11 in the bile duct. Here, the proximal balloon 13 does not necessarily constitute a locking portion only when it is fully deployed. If the proximal balloon 13 is deployed and comes into contact with the outer portion of the common bile duct 6, and is locked into the locking portion on the biological lumen side, that is, if the axial movement of the catheter body 11 toward the tip is restricted and the catheter body 11 is positioned in the bile duct, then in this state, the proximal balloon 13 can be said to constitute a locking portion.

[0047] For example, the proximal balloon 13 may be positioned within the duodenum, and the tip of the proximal balloon 13 may be brought into contact with the papilla 5. In this case, the catheter body 11 can be positioned using the papilla 5 as the locking part and the tip of the proximal balloon 13 as the locking part.

[0048] Alternatively, for example, the catheter 10 may be advanced so that the tip balloon 12 is positioned within the common tube 8 where the common bile duct 6 and the pancreatic duct 7 merge, and the tip of the proximal balloon 13 may be brought into contact with the bifurcation 9 of the common bile duct 6 and the pancreatic duct 7. In this case, the bifurcation 9 within the common tube 8 can be used as the locking point, and the tip of the proximal balloon 13 can be used as the locking point to position the catheter body 11.

[0049] Alternatively, for example, the catheter 10 may be advanced so that the proximal balloon 13 is positioned within the common tube 8, bringing the tip of the proximal balloon 13 into contact with the branch 9 within the common tube 8, and the outer circumference of the proximal balloon 13 into contact with the inner wall of the common tube 8. In this case, the catheter body 11 can be positioned using the branch 9 and the inner wall of the common tube 8 as locking parts, and the tip of the proximal balloon 13 in contact with the branch 9 and the outer circumference of the proximal balloon 13 in contact with the inner wall of the common tube 9 as locking parts. Alternatively, the catheter 10 may be advanced so that the proximal balloon 13 is positioned within the common tube 8, and the catheter body 11 may be positioned by bringing the outer circumference of the proximal balloon 13 into contact with the inner wall of the common tube 8, without the proximal balloon 13 contacting the branching portion 9 within the common tube 8.

[0050] Here, the radial length D2 of the proximal balloon 13 in its deployed state is appropriately defined depending on the manner in which the catheter body 11 is secured. When the proximal balloon 13 is placed in the duodenum and in contact with the papilla, or when it is placed in the common tube, the value of the radial length D2 is, for example, 8 mm to 30 mm. The ratio of D2 to D1 (D2 / D1) can be appropriately set depending on the manner of use.

[0051] Furthermore, the axial length L2 of the proximal balloon 13 is determined by factors such as the difference between the profile (diameter) of the proximal balloon 13 when it is contracted and the radial length D2 of the proximal balloon 13 when it is deployed, and the degree of expansion and contraction of the membrane of the proximal balloon 13. For example, if the difference between the profile of the proximal balloon 13 when it is contracted and the above-mentioned D2 is large, L2 tends to be longer, and if the degree of expansion and contraction of the membrane of the proximal balloon 13 is small, L2 also tends to be longer. Although not particularly limited, the above-mentioned value of L2 is, for example, 5 mm to 20 mm. Note that the ratio of L2 to L1 (L2 / L1) can be set as appropriate depending on the usage.

[0052] Figure 4 is an enlarged view showing the base end of the deployed tip balloon 12 and the tip end of the deployed base balloon 13. Figures 5(a) to (c) show examples of the attachment state of the base end of the tip balloon 12 and the tip end of the base balloon 13.

[0053] As shown in Figure 4, in the axial direction of the catheter body 11, the proximal end connected to the catheter body 11 at the tip balloon 12 and the tip end connected to the catheter body 11 at the proximal balloon 13 are positioned adjacent to each other.

[0054] Here, the shape of the tip balloon 12 in the deployed state is, for example, an oval shape. Therefore, the base end P1 of the tip balloon 12 is the most base end, located furthest to the base in the axial direction of the tip balloon. On the other hand, the base balloon 13 in the deployed state has a shape in which the outer part protrudes axially outward relative to the inner part, and the inner part is constricted axially inward. Therefore, in the deployed base balloon 13, the outer part P2 protrudes towards the tip side than the tip end P2' of the base balloon, and this part P2 becomes the furthest tip, located furthest to the axial direction of the base balloon 13 in the deployed state.

[0055] As the proximal balloon 13 expands to protrude significantly toward the tip, the leading edge (P2) of the deployed proximal balloon 13 is located further toward the tip than the most proximal end (P1) of the tip balloon 12. This reduces the gap (constriction) between the tip balloon 12 and the proximal balloon 13 when the balloons are deployed.

[0056] Furthermore, as shown in Figure 2, in the deployed proximal balloon 13, at least a portion of the tip portion that protrudes further towards the tip than the tip end of the proximal balloon 13 can be in close contact with the deployed tip balloon 12. However, the deployed proximal balloon 13 does not necessarily have to be in close contact with the tip balloon 12.

[0057] For example, the tips of the inflated tip balloon 12 and the proximal balloon 13 may come into contact at a single point, with the balloon with higher internal pressure pressing against the other balloon with lower internal pressure, or the balloons pressing against each other, resulting in the tip of the proximal balloon 13 being in close contact with the tip balloon 12. Alternatively, the contact area between the tip balloon 12 and the proximal balloon 13 may extend further axially from a single point, so that the tip of the proximal balloon 13 comes into planar contact with the tip balloon 12, creating a tight seal.

[0058] To facilitate the deployment of the tip balloon 12 and proximal balloon 13 as described above, it is preferable that at least one of the proximal end of the tip balloon 12 and the tip end of the proximal balloon 13 is attached to the catheter body 11 by folding the balloon membrane in the opposite direction axially relative to other balloons adjacent in the axial direction, as shown in Figures 5(a) to (c).

[0059] In the example shown in Figure 5(a), the proximal end of the tip balloon 12 is attached outward to the catheter body 11 so that the membrane of the tip balloon 12 faces the proximal end. The proximal end of the tip balloon 12 in Figure 5(a) may be fixed to the catheter body 11 with adhesive, or it may be fixed to the catheter body 11 using a combination of adhesive and heat shrink tubing.

[0060] On the other hand, at the tip end of the proximal balloon 13 in Figure 5(a), a folded portion 13a of the membrane is formed, and the membrane of the proximal balloon 13 is folded back toward the opposite side (proximal side) from the tip balloon before being attached to the catheter body 11. The tip end (folded portion 13a) of the proximal balloon 13 in Figure 5(a) may be fixed to the catheter body with adhesive, or it may be fixed to the catheter body 11 using a combination of adhesive and heat shrink tubing.

[0061] In the example shown in Figure 5(b), a folded portion 12a of the membrane is formed at the proximal end of the tip balloon 12, and the membrane of the tip balloon 12 is folded back toward the opposite side (tip side) from the proximal balloon 13 before being attached to the catheter body 11. In Figure 5(b), the proximal end (folded portion 12a) of the tip balloon 12 may be fixed to the catheter body with adhesive, or it may be fixed to the catheter body 11 using a combination of adhesive and heat shrink tubing.

[0062] On the other hand, at the tip end of the proximal balloon 13 in Figure 5(b), the membrane of the proximal balloon 13 is attached outward relative to the catheter body 11 so that it faces the tip. The tip end of the proximal balloon 13 in Figure 5(b) may be fixed to the catheter body 11 with adhesive, or it may be fixed to the catheter body 11 using a combination of adhesive and heat shrink tubing.

[0063] In the example shown in Figure 5(c), a folded portion 12a of the membrane is formed at the proximal end of the tip balloon 12, and the membrane of the tip balloon 12 is folded back toward the opposite side (tip side) relative to the proximal balloon 13 before being attached to the catheter body 11. Similarly, a folded portion 13a of the membrane is also formed at the tip end of the proximal balloon 13 in Figure 5(c), and the membrane of the proximal balloon 13 is folded back toward the opposite side (proximal side) relative to the tip balloon 12 before being attached to the catheter body 11. Note that the proximal end (folded portion 12a) of the tip balloon 12 and the tip end (folded portion 13a) of the proximal balloon 13 in Figure 5(c) may be fixed to the catheter body with adhesive, or they may be fixed to the catheter body using a combination of adhesive and heat shrink tubing.

[0064] Next, we will describe the first marker 14 and the second marker 15. The first marker 14 and the second marker 15 are respectively located within the attachment area of ​​the tip balloon 12 of the catheter body 11 (the range from the tip end to the proximal end of the tip balloon 12).

[0065] The first marker 14 is an optically visible marker formed on the catheter body 11, and is provided for the operator to visually confirm the position of the catheter body 11 during endoscopic observation. The first marker 14 only needs to be identifiable by the illumination light of the duodenal endoscope 1, and can be formed, for example, by applying paint or coating to the catheter body 11.

[0066] As an example, the first marker 14 is positioned in the center of the attachment area of ​​the tip balloon 12. By positioning the first marker 14 in the center of the attachment area of ​​the tip balloon 12, the operator can more easily intuitively grasp the position of the tip balloon 12 on the catheter body 11 during endoscopic observation. However, the position of the first marker 14 is not limited to the above example; the first marker 14 may be positioned at a location shifted towards the tip or proximal end from the center of the attachment area, as long as the operator can grasp the position of the catheter body 11 from the first marker 14 during endoscopic observation. Furthermore, the first marker 14 may be positioned more proximal to the second marker 15 on the proximal end, as described later, and more proximal to the second marker 15 on the tip, as described later. Note that Figure 2 shows an example where one first marker 14 is positioned on the catheter body 11, but multiple first markers 14 may be positioned on the catheter body 11.

[0067] The second marker 15 is a thin-walled ring or tubular body made of an X-ray opaque material. The second marker 15 is provided to allow the operator to confirm the position of the tip balloon 12 under X-ray contrast. Examples of materials for the second marker 15 include tungsten, tantalum, and platinum (iridium).

[0068] The second marker 15 is provided in the mounting area of ​​the tip balloon 12, at the tip and base ends of the cylindrical portion that constitutes the radial length D1 when the tip balloon 12 is deployed. The distance between the tip and base second markers 15 is specified to be greater than the range of the target position. For example, Figure 2 shows an example where the second markers 15 are positioned to match the tip and base ends of the cylindrical portion that constitutes the radial length D1 when the tip balloon 12 is deployed. However, the tip-side second marker 15 in Figure 2 may be provided closer to the base end, and the base-side second marker 15 in Figure 2 may be provided closer to the tip end.

[0069] Next, an example of how the catheter 10 is used in this embodiment will be described. As an example, the deployment of the proximal balloon 13 and the distal balloon 12 of the catheter 10 is performed in the following procedure.

[0070] First, a duodenal endoscope 1 is introduced into the patient's body, and the tip of the tubular insertion section 2 is positioned near the papilla 5 of the duodenum 4. Next, a catheter 10 is inserted into the lumen (forceps channel) of the duodenal endoscope 1 from the proximal end. By advancing the catheter 10 toward the tip of the tubular insertion section 2, the tip of the catheter 10 protrudes from the forceps channel of the tubular insertion section 2 and is exposed into the duodenum 4.

[0071] The operator manipulates the catheter 10 while checking the image from the duodenal endoscope 1, and inserts the tip of the catheter 10 into the common bile duct 6. Then, while confirming the position of the first marker 14 of the catheter 10 on the image from the duodenal endoscope 1, the operator positions the tip balloon 12, before deployment, near the target position (Figure 1(a)).

[0072] Next, the operator supplies expansion fluid to the proximal balloon 13 of the catheter 10 from a proximal fluid supply syringe (not shown), inflating the proximal balloon 13. The radially expanded proximal balloon 13 forms a locking portion that abuts against a locking portion on the biological lumen side outside the common bile duct 6 (for example, the papilla 5, the bifurcation 9 of the common bile duct 6 and the pancreatic duct 7, the inner wall of the common tube 8, etc.).

[0073] The operator advances the tip of the catheter 10 toward the tip, for example, until the tip of the proximal balloon 13, which is deployed outside the common bile duct 6, contacts the locking portion. When the tip of the proximal balloon 13 contacts the locking portion, the proximal balloon 13 acts as a stopper, positioning the tip balloon 12 at the target position in the common bile duct 6 in the axial direction of the catheter 10 (Figure 1(b)). In addition, the contact of the proximal balloon 13 with the locking portion outside the common bile duct 6 prevents the catheter body 11 inserted into the common bile duct 6 from being pushed too far into the bile duct.

[0074] The operator confirms by X-ray contrast whether the proximal and distal second markers 15 are positioned on opposite sides of the target location in the common bile duct 6 (i.e., whether the distal balloon 12 is positioned at the target location in the common bile duct 6). With the distal balloon 12 positioned at the target location in the common bile duct 6, the operator supplies dilation fluid to the distal balloon 12 of the catheter 10 from a proximal fluid syringe (not shown) to inflate the distal balloon 12 (Figure 1(c)). This expands the target location in the common bile duct 6 by the distal balloon 12.

[0075] The operation of the catheter 10 in this embodiment will be described below. In this embodiment, the catheter 10 is inserted into the common bile duct (bile duct) 6 at its tip. The catheter 10 comprises a catheter body 11 extending in the axial direction, a tip balloon 12 positioned on the tip side of the catheter body 11 and capable of maintaining a predetermined radial length D1 when pressure exceeding a predetermined inflation pressure is applied, and a proximal balloon 13 positioned adjacent to the proximal end of the tip balloon 12 on the catheter body 11 and capable of gradually expanding in response to an increase in inflation pressure. The radial length D2 of the proximal balloon 13 in its deployed state is greater than the radial length D1 of the tip balloon 12 in its deployed state (D2 > D1), and the proximal balloon 13, when deployed, forms a locking portion outside the common bile duct 6. According to this embodiment, the proximal balloon 13, which expands radially more than the distal balloon 12, is positioned on the proximal side of the distal balloon 12, thereby forming a locking portion for the catheter 10 on the outside of the common bile duct 6. This suppresses displacement of the distal balloon 12 toward the distal side, making it easier to deploy the distal balloon 12 at the target position in the common bile duct 6 during the procedure. Furthermore, the proximal balloon 13 is a relatively flexible and easily expandable balloon that can gradually expand in response to an increase in inflation pressure. The proximal balloon 13 expands radially outward more than the distal balloon 12, which can maintain a predetermined radial length D1, but because its membrane is more flexible and easily expandable than that of the distal balloon 12, it is relatively easy to suppress the profile of the proximal balloon 13 when it deflates. Therefore, despite having a proximal balloon 13 that expands radially, the catheter 10 of this embodiment can be loaded into a small-diameter sheath relatively easily, thereby reducing the invasiveness of the catheter 10.

[0076] Furthermore, in the axial direction, the outermost tip (P2) of the deployed proximal balloon 13 is located closer to the tip than the outermost tip (P1) of the deployed distal balloon 12. As a result, according to this embodiment, the gap (constriction) between the distal balloon 12 and the proximal balloon 13 becomes smaller when the balloons are deployed, making it less likely for body tissues (such as the papilla 5 or bifurcation 9) to get caught between the balloons during the procedure.

[0077] Furthermore, if the gap (constriction) between the tip balloon 12 and the proximal balloon 13 is large, the papilla may become trapped in the gap, potentially resulting in insufficient dilation of the papilla. In the catheter 10 of this embodiment, the gap (constriction) between the tip balloon 12 and the proximal balloon 13 is small when the balloon is deployed, making it less likely for the papilla to become trapped in the gap, thereby suppressing the occurrence of the above-mentioned problem.

[0078] Furthermore, by ensuring that at least a portion of the tip portion, including the very tip (P2) of the deployed proximal balloon 13, is in close contact with the deployed tip balloon 12, the gap between the tip balloon 12 and the proximal balloon 13 in the deployed state can be further reduced.

[0079] Further, the membrane body of the proximal balloon 13 has a lower hardness than the membrane body of the distal balloon 12. According to this embodiment, even when the deployed proximal balloon 13 contacts body tissues such as the papilla 5, the proximal balloon 13 is less likely to damage the normal body tissues outside the common bile duct 6, and the invasiveness of the catheter 10 can be further reduced.

[0080] Further, the axial length L2 of the proximal balloon 13 is smaller than the axial length L1 of the distal balloon 12 (L2 < L1). By making the axial length of the proximal balloon 13, which is relatively flexible and easy to expand and contract compared to the distal balloon 12, shorter than that of the distal balloon 12, an increase in the profile of the catheter 10 during balloon contraction can be suppressed while making the catheter 10 compact in the axial direction.

[0081] Further, at least one of the proximal end portion of the distal balloon 12 and the distal end portion of the proximal balloon 13 is attached to the catheter body 11 by folding the balloon membrane body to the opposite side in the axial direction with respect to the other balloon adjacent in the axial direction. As a result, the balloon is likely to expand so as to protrude with respect to the other balloon adjacent in the axial direction, and it becomes easy to reduce the gap (constriction) between the distal balloon 12 and the proximal balloon 13 in the deployed state of the balloon.

[0082] Further, the catheter body 11 has a first marker 14 that can be optically visualized within the attachment region of the distal balloon 12. Thereby, the operator can position the distal balloon 12 before deployment in the common bile duct 6 based on the position of the first marker 14 by the image of the duodenal endoscope 1.

[0083] Further, the catheter body 11 has second markers 15 that are radiopaque on the distal side and the proximal side within the attachment region of the distal balloon 12. Thereby, even when the proximal balloon 13 is deployed and the position of the distal balloon 12 cannot be confirmed from the side of the duodenal endoscope 1, the operator can confirm by X-ray imaging whether the distal balloon 12 is positioned at the target position of the common bile duct 6.

[0084] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention.

[0085] For example, in the above embodiment, a configuration in which a pair of expansion fluid lumens are formed in a single-tube catheter body 11 was described, but the configuration of the catheter body 11 is not limited to this.

[0086] As an example, the catheter body 11 may be formed of three concentrically arranged tubes, as shown in Figure 6. The catheter body 11 shown in Figure 6 has a first tube 31 located on the inner circumference, a second tube 32 located in the middle, and a third tube 33 located on the outer circumference.

[0087] A main lumen 34 is formed inside the first tube 31. The second tube 32 houses the first tube 31 inside. The tip of the first tube 31 protrudes from the tip of the second tube 32. A tip balloon 12 is attached to the tip of the second tube 32 and to the outer surface of the first tube 31 that protrudes from the second tube 32 at the tip end of the catheter body 11. An annular gap 35 communicating with the tip balloon 12 is formed between the first tube 31 and the second tube 32, and the gap 35 functions as an expansion fluid lumen that supplies expansion fluid to the tip balloon 12.

[0088] Furthermore, the third tube 33 houses the second tube 32 inside. The tip of the second tube 32 protrudes from the tip of the third tube 33. On the tip side of the catheter body 11, a proximal balloon 13 is attached to the tip of the third tube 33 and to the outer surface of the second tube 32 protruding from the third tube 33, on the proximal side of the tip balloon 12. In addition, an annular gap 36 communicating with the proximal balloon 13 is formed between the second tube 32 and the third tube 33, and the gap 36 functions as an expansion fluid lumen that supplies expansion fluid to the proximal balloon 13. Even when the catheter body 11 configuration shown in Figure 6 is applied, the same effects as in the above embodiment can be obtained.

[0089] As another example, the catheter body 11 may be formed of two concentrically arranged tubes, as shown in Figure 7. The catheter body 11 shown in Figure 7 has a first tube 31 located on the inner circumference and a second tube 32 located on the outer circumference.

[0090] A main lumen 34 is formed inside the first tube 31. The second tube 32 houses the first tube 31 inside. The tip of the first tube 31 protrudes from the tip of the second tube 32. A tip balloon 12 is attached to the tip of the second tube 32 and to the outer surface of the first tube 31 that protrudes from the second tube 32 at the tip end of the catheter body 11. An annular gap 35 is formed between the first tube 31 and the second tube 32, communicating with the tip balloon, and the gap 35 functions as an expansion fluid lumen that supplies expansion fluid to the tip balloon 12.

[0091] At the tip of the catheter body 11, a proximal balloon 13 is attached to the outer surface of the second tube 32, proximal to the tip balloon 12. An expansion fluid lumen 37 is formed inside the second tube 32 along the axial direction. As shown in Figure 7(a), the expansion fluid lumen 37 of the second tube 32 communicates with the outer surface of the catheter body 11 in the attachment area of ​​the proximal balloon 13. This allows expansion fluid to be supplied from the expansion fluid lumen 37 of the second tube 32 to the proximal balloon 13. While Figure 7 shows an example with two expansion fluid lumens 37 inside the second tube 32, the second tube 32 may have one or more expansion fluid lumens 37. Even when the catheter body 11 configuration shown in Figure 7 is applied, the same effects as in the above embodiment can be obtained.

[0092] Furthermore, although the above embodiment describes a catheter inserted into the bile duct, the catheter of the present invention may also be applied to biological lumens other than the bile duct. For example, the catheter of the present invention can be widely applied to procedures in which it is inserted into another biological lumen branching off from the main lumen where an endoscope is placed, and the other biological lumen is expanded with a balloon via the endoscope.

[0093] Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0094] Furthermore, the disclosure of the above embodiments encompasses the following technical concepts. (1) A catheter whose tip is inserted into the bile duct, comprising: a catheter body extending in the axial direction; a tip balloon disposed on the tip side of the catheter body and capable of maintaining a predetermined radial length when pressure exceeding a predetermined inflation pressure is applied; and a proximal balloon disposed on the catheter body adjacent to the proximal end of the tip balloon and capable of gradually expanding in response to an increase in inflation pressure, wherein the radial length of the proximal balloon in the deployed state is greater than the radial length of the tip balloon in the deployed state, and the proximal balloon, when deployed, forms a locking portion on the outside of the bile duct. (2) The catheter according to (1) above, wherein in the axial direction, the leading edge of the proximal balloon in the deployed state is located more towards the tip than the most proximal end of the leading edge balloon in the deployed state. (3) The catheter described in (2) above, wherein at least a portion of the tip portion of the proximal balloon in the deployed state, including the furthest tip, is in close contact with the furthest balloon in the deployed state. (4) The catheter according to any one of the above items (1) to (3), wherein the membrane of the proximal balloon is less rigid than the membrane of the distal balloon. (5) The catheter according to any one of the above items (1) to (4), wherein the axial length of the proximal balloon is smaller than the axial length of the distal balloon. (6) The catheter according to any one of the above items (1) to (5), wherein at least one of the proximal end of the tip balloon and the tip end of the proximal balloon is attached to the catheter body by folding the balloon membrane in the opposite direction axially relative to other balloons adjacent in the axial direction. (7) The catheter according to any one of the above items (1) to (6), wherein the catheter body has an optically visible first marker within the attachment area of ​​the tip balloon. (8) The catheter body is the catheter according to any one of the above items (1) to (7), wherein the catheter body has radiopaque second markers on the tip and proximal ends within the attachment area of ​​the tip balloon. [Explanation of Symbols]

[0095] 1…Duodenal endoscope, 2…Tubular insertion section, 4…Duodenum, 5…Papilla, 6…Common bile duct (bile duct), 7…Pancreatic duct, 8…Common tube, 9…Branch, 10…Catheter, 11…Catheter body, 12…Proximal balloon, 13…Proximal balloon, 14…First marker, 15…Second marker, 21,34…Main lumen, 22a,22b,37…Dilation fluid lumen, 31…First tubular body, 32…Second tubular body, 33…Third tubular body, 35,36…Cavity

Claims

1. A catheter whose tip is inserted into the bile duct, A catheter body extending in the axial direction, A tip balloon is positioned at the tip end of the catheter body and is capable of maintaining a predetermined radial length when pressure exceeding a predetermined inflation pressure is applied. The catheter comprises a proximal balloon positioned adjacent to the proximal end of the aforementioned tip balloon, and capable of gradually expanding in response to an increase in inflation pressure, The radial length of the base balloon in the deployed state is greater than the radial length of the tip balloon in the deployed state. The proximal balloon, when deployed, forms a locking portion on the outside of the bile duct. catheter.

2. In the axial direction, the leading edge of the deployed base balloon is located further forward than the most base end of the deployed tip balloon. The catheter according to claim 1.

3. At least a portion of the tip portion of the proximal balloon in the deployed state, including the furthest tip, is in close contact with the furthest tip balloon in the deployed state. The catheter according to claim 2.

4. The membrane of the proximal balloon has lower rigidity than the membrane of the tip balloon. The catheter according to any one of claims 1 to 3.

5. The axial length of the proximal balloon is smaller than the axial length of the tip balloon. The catheter according to any one of claims 1 to 3.

6. At least one of the proximal end of the tip balloon and the tip end of the proximal balloon is attached to the catheter body by folding the balloon membrane in the opposite direction axially relative to other balloons adjacent in the axial direction. The catheter according to any one of claims 1 to 3.

7. The catheter body has an optically visible first marker within the attachment area of ​​the tip balloon. The catheter according to any one of claims 1 to 3.

8. The catheter body has radiopaque second markers on both the tip and proximal ends within the attachment area of ​​the tip balloon. The catheter according to any one of claims 1 to 3.

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