Bile aspiration catheter

Abstract

To provide a bile aspiration catheter capable of washing a further deep part in a bile duct and easily washing away bile attached to the inner wall of the bile duct.SOLUTION: A catheter for being inserted into a bile duct to aspirate bile, comprises a shaft 2 extending in a longitudinal direction from a proximal side to a distal side, a first lumen 4 provided in the shaft 2, extending in the longitudinal direction, and having a liquid discharge port 5 at a distal end, and a second lumen 7 provided in the shaft 2, extending in the longitudinal direction, and having a liquid aspiration port 8 at the distal end. The liquid discharge port 5 is located on the distal side with respect to the liquid suction port 8. The first lumen 4 includes a constricted part 14 at the distal end, and a cross-sectional area of the first lumen 4 at the constricted part 14 is formed narrower than those on the distal side and the proximal side.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a bile aspiration catheter.

Background Art

[0002] When the bile duct is blocked by gallstones, tumors, etc., or the flow of bile in the bile duct is inhibited, bile may stagnate in the bile duct and cause bacterial infection. Bacterial infection of bile can lead to cholangitis, and if the bile containing bacteria further flows into the systemic blood through the liver, it may cause sepsis. In such cases, a treatment for discharging bile from the bile duct is required, and percutaneous transhepatic cholangial drainage (PTCD), endoscopic retrograde biliary drainage (ERBD), etc. are performed.

[0003] As a catheter used by being inserted into the bile duct, for example, in Patent Document 1, there is a bile duct drainage catheter including a catheter tube whose distal end side is inserted into the bile duct. The catheter tube has a main body portion whose outer diameter is substantially the same along the longitudinal direction, a first tapered portion that is continuous with the distal end side of the main body portion and whose outer diameter becomes thinner toward the distal end side, a small-diameter straight body portion that is continuous with the distal end side of the first tapered portion and whose outer diameter is substantially the same along the longitudinal direction, and a second tapered portion that is continuous with the distal end side of the small-diameter straight body portion and whose outer diameter becomes thinner toward the distal end side. A bile duct drainage catheter is disclosed in which the outer diameter of the small-diameter straight body portion is 20 to 80% of the outer diameter of the main body portion, and the length of the small-diameter straight body portion is 30 to 250 mm. Patent Document 2 discloses an elongated medical member including a long insertion portion provided with a plurality of lumens through which a working treatment tool for performing a predetermined medical act can be inserted, and a guide portion extending from the tip of the insertion portion for guiding the insertion portion. An opening is formed in the tip surface of the guide portion, and fluid supply lumens are formed in the insertion portion and the guide portion. Patent Document 2 describes that bile in the bile duct may be aspirated from the opening at the tip of the insertion portion.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-329314 [Patent Document 2] Japanese Patent Publication No. 2011-251140 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] When aspirating bile from the bile duct using a catheter, it is desirable to be able to remove not only the bile accumulated in the bile duct but also the bile adhering to the inner wall of the bile duct. The present invention has been made in view of the above circumstances, and its purpose is to provide a bile aspiration catheter that can clean deeper into the bile duct and easily wash away bile adhering to the inner wall of the bile duct. [Means for solving the problem]

[0006] The bile aspiration catheter of the present invention, which has been able to solve the aforementioned problems, is a catheter for aspirating bile by insertion into the bile duct, and comprises a shaft extending longitudinally from the proximal to the distal side, a first lumen provided on the shaft and extending longitudinally, having a liquid discharge port at its distal end, and a second lumen provided on the shaft and extending longitudinally, having a liquid aspiration port at its distal end, wherein the liquid discharge port is located distal to the liquid aspiration port, the first lumen has a constricted portion at its distal end, and the cross-sectional area of ​​the first lumen at the constricted portion is formed to be narrower than that of its distal and proximal sides.

[0007] The bile aspiration catheter of the present invention can dilute the bile accumulated in the bile duct and reduce its viscosity by discharging a lavage solution into the bile duct from the liquid discharge port. This makes it easier to aspirate the bile, which has been diluted and reduced in viscosity by the lavage solution, from the liquid aspiration port. At that time, as described above, a constriction is formed at the distal end of the first lumen, allowing the lavage solution to be discharged radially toward the distal side from the liquid discharge port. This makes it possible to clean deeper into the bile duct and makes it easier to wash away bile adhering to the inner wall of the bile duct.

[0008] The constriction section is preferably formed proximal to the liquid discharge port and distal to the liquid suction port. This configuration facilitates the discharge of the cleaning liquid distally from the liquid discharge port, spreading radially.

[0009] Preferably, the first lumen has a constricted section on the proximal side of the constriction where the inner diameter of the first lumen decreases from the proximal side to the distal side, and an expanded section on the distal side of the constriction where the inner diameter of the first lumen increases from the proximal side to the distal side. By forming the distal end of the first lumen in this way, the cleaning liquid can pass through the constriction smoothly, and the pressure loss when the cleaning liquid passes through the constriction can be reduced. Therefore, it becomes easier to forcefully discharge the cleaning liquid distally from the liquid outlet.

[0010] It is preferable that the shaft has a tapered section distal to the liquid aspirator port, where the outer diameter decreases towards the distal end. This shape of the shaft tip makes it easier to insert the shaft into the bile duct.

[0011] In a cross-section perpendicular to the longitudinal direction of the shaft, it is preferable that the cross-sectional area of ​​the first lumen is smaller than that of the second lumen. This makes it easier to forcefully discharge the cleaning fluid from the liquid outlet of the first lumen, facilitating cleaning deeper into the bile duct. It also reduces the likelihood of the second lumen becoming clogged when aspirating bile from its liquid suction port. [Effects of the Invention]

[0012] The bile aspiration catheter of the present invention has a constriction formed at the distal end of the first lumen, which has a liquid discharge port at its distal end. This allows the lavage fluid to be discharged radially from the liquid discharge port toward the distal end. As a result, it is possible to lavage deeper into the bile duct and to easily wash away bile adhering to the inner wall of the bile duct. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of a bile aspiration catheter according to an embodiment of the present invention, and represents an overall side view of the bile aspiration catheter. [Figure 2] Figure 1 shows a side view of the distal end of the bile aspiration catheter. [Figure 3] Figure 1 shows a perspective view of the distal end of the bile aspiration catheter. [Figure 4] Figure 2 shows a cross-sectional view of the distal end of the bile aspiration catheter along its longitudinal direction. [Figure 5] Figure 4 shows a modified example of a cross-sectional view along the longitudinal direction of the distal end of the bile aspiration catheter. [Figure 6] Figure 1 shows a cross-sectional view of the bile aspiration catheter from point VI to VI. [Figure 7] Figure 2 shows a modified side view of the distal end of the bile aspiration catheter. [Modes for carrying out the invention]

[0014] The bile aspiration catheter of the present invention will be described in detail below based on the embodiments described below. However, the present invention is not limited by the embodiments described below, and it is certainly possible to implement the invention with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of the present invention.

[0015] Referring to FIGS. 1 to 7, a bile aspiration catheter according to an embodiment of the present invention will be described. FIG. 1 is an example of a bile aspiration catheter according to an embodiment of the present invention, showing an overall side view of the bile aspiration catheter. FIGS. 2 and 3 respectively show a side view and a perspective view of the distal end portion of the bile aspiration catheter shown in FIG. 1. FIG. 6 shows a VI-VI cross-sectional view of the bile aspiration catheter shown in FIG. 1. Further, FIG. 5 shows a cross-sectional view along the longitudinal direction of the distal end portion of the bile aspiration catheter shown in FIG. 4 and a modified example thereof. FIG. 7 shows a modified example of the side view of the distal end portion of the bile aspiration catheter shown in FIG. 2.

[0016] The bile aspiration catheter 1 is a catheter used for inserting into the bile duct and aspirating bile. The bile aspiration catheter 1 of the present invention can aspirate the bile accumulated in the bile duct while supplying a liquid into the bile duct and washing the inside of the bile duct. Hereinafter, the bile aspiration catheter will be simply referred to as "catheter".

[0017] The catheter 1 has a shaft 2 extending in the longitudinal direction. In the catheter 1, the longitudinal direction is determined based on the extending direction of the shaft 2. The catheter 1 has a proximal side and a distal side as one side and the other side with respect to the longitudinal direction. The proximal side refers to the direction on the side of the user of the catheter 1, that is, the side of the surgeon's hand. The distal side refers to the opposite direction to the proximal side, that is, the direction on the side of the treatment target. The shaft 2 has a radial direction as a direction orthogonal to the longitudinal direction. In FIG. 1, the right side of the figure corresponds to the proximal side, and the left side of the figure corresponds to the distal side.

[0018] The shaft 2 has a first lumen 4 having a liquid discharge port 5 at its distal end and a second lumen 7 having a liquid suction port 8 at its distal end. The first lumen 4 and the second lumen 7 each extend in the longitudinal direction and are arranged side by side in the radial direction. The shaft 2 has a first tube 3 and a second tube 6, and the inner cavity of the first tube 3 can be used as the first lumen 4, and the inner cavity of the second tube 6 can be used as the second lumen 7. The first tube 3 and the second tube 6 are arranged side by side, a liquid discharge port 5 is formed at the distal end of the first tube 3, and a liquid suction port 8 is formed at the distal end of the second tube 6. The first tube 3 and the second tube 6 are preferably welded or adhered to each other and integrated, or the first tube 3 and the second tube 6 are arranged in the inner cavity of the protective tube 9, and the first tube 3 and the second tube 6 are integrated by the protective tube 9. Although not shown in the drawings, it is also possible to form two inner cavities in one tube to serve as the first lumen and the second lumen.

[0019] When using the catheter 1, a liquid (washing liquid) to be supplied into the bile duct flows through the first lumen 4, and the liquid is discharged into the bile duct from the liquid discharge port 5 at the distal end of the first lumen 4. Therefore, the first lumen 4 preferably has a proximal opening, and a liquid supply part is preferably provided in communication with the proximal opening of the first lumen 4. Examples of the liquid supply part include a syringe and a pump.

[0020] Bile and the like accumulated in the bile duct are sucked from the liquid suction port 8 at the distal end of the second lumen 7 and discharged from the bile duct through the second lumen 7. Therefore, the second lumen 7 preferably has a proximal opening, and a liquid suction part is preferably provided in communication with the proximal opening of the second lumen 7. Examples of the liquid suction part include a syringe and a pump. A backlock syringe may be used as the syringe of the liquid suction part.

[0021] Lumen 4 (the first lumen) can also serve as the guidewire lumen. By having Lumen 4 (the first lumen) also serve as the guidewire lumen, the outer diameter of shaft 2 can be reduced. In addition, bile can be aspirated or the bile duct can be irrigated without removing the guidewire, leading to a simplification of the procedure and a reduction in surgical time.

[0022] It is preferable that a hub 10 is provided on the proximal side of the shaft 2. The hub 10 has a supply connection port 11 that communicates with the first lumen 4 and a suction connection port 12 that communicates with the second lumen 7, and it is preferable that the liquid supply unit is connected to the supply connection port 11 of the hub 10 and the liquid suction unit is connected to the suction connection port 12 of the hub 10. By providing the hub 10, the operability of the catheter 1 can be improved.

[0023] The hub 10 preferably further has a guide wire port 13. The guide wire port 13 is preferably provided in communication with the first lumen 4. In this case, inside the hub 10, the internal passage communicating with the first lumen 4 branches into two, with one branch connecting to the supply connection port 11 and the other connecting to the guide wire port 13.

[0024] The hub 10 may further have auxiliary ports into which other medical devices can be inserted. The auxiliary ports can be provided, for example, in communication with the second lumen 7. In this case, the internal passage in the hub 10 that communicates with the second lumen 7 branches into two, one of which connects to the suction connection port 12 and the other to the auxiliary port. Examples of other medical devices include cytological brushes, which allow for the collection of a specimen for cytology immediately after bile aspiration.

[0025] A check valve may be provided in the internal passage of the hub 10. For example, by providing a check valve in the internal passage connecting the first lumen 4 of the hub 10 and the supply connection port 11, liquid can be flowed in one direction from the supply connection port 11 towards the first lumen 4. By providing a check valve in the internal passage connecting the second lumen 7 of the hub 10 and the suction connection port 12, liquid can be flowed in one direction from the second lumen 7 towards the suction connection port 12.

[0026] Although not shown in the drawings, a first hub connected to the first lumen 4 and a second hub connected to the second lumen 7 may be provided on the proximal side of the shaft 2. The first hub and / or the second hub may have internal passages that branch into two or more, and each internal passage may have two or more ports communicating with it. For example, the first hub connected to the first lumen 4 may have a supply connection port 11 and a guide wire port 13. The second hub connected to the second lumen 7 may have a suction connection port 12 and the auxiliary ports described above. Check valves may be provided in the internal passages of the first hub and / or the second hub.

[0027] The longitudinal length of shaft 2 is preferably 1500 mm or more, more preferably 1800 mm or more, preferably 3000 mm or less, and more preferably 2800 mm or less. The outer diameter of shaft 2 is preferably 1.2 mm or more, more preferably 1.3 mm or more, even more preferably 1.4 mm or more, preferably 8.0 mm or less, more preferably 7.0 mm or less, and even more preferably 6.0 mm or less. The outer diameter of shaft 2 may be even smaller, for example 4.0 mm or less, 3.6 mm or less, or 3.2 mm or less. The inner diameters of the first lumen 4 and the second lumen 7 are preferably 1.0 mm or more, more preferably 1.1 mm or more, even more preferably 1.3 mm or more, preferably 3.5 mm or less, more preferably 3.0 mm or less, and even more preferably 2.5 mm or less. The inner diameters of the first lumen 4 and the second lumen 7 may be even smaller, for example 2.2 mm or less, 2.0 mm or less, or 1.9 mm or less.

[0028] In a cross-section perpendicular to the longitudinal direction of shaft 2, the shape of the outer edge of shaft 2, the shape of the outer edge of the first tube 3, the shape of the outer edge of the second tube 6, the shape of the first lumen 4, and the shape of the second lumen 7 are not particularly limited and can be circular, elliptical, oblong, egg-shaped, polygonal, irregular, etc. If the shape of the outer edge of shaft 2 or the shapes of the first lumen 4 and the second lumen 7 are not circular, the outer diameter of shaft 2 and the inner diameters of the first lumen 4 and the second lumen 7 described above represent the average value of the major axis and the minor axis. Regarding the major axis and minor axis, taking the outer edge of shaft 2 as an example, the major axis of the outer edge of shaft 2 means the length in the major axis direction of the outer edge of shaft 2 (the maximum diameter of the outer edge), and the minor axis of the outer edge of shaft 2 means the longest length in the minor axis direction that is perpendicular to the major axis direction of shaft 2. Furthermore, the shape of the outer edge of shaft 2, the shape of the outer edge of the first tube 3, the shape of the outer edge of the second tube 6, the shape of the first lumen 4, and the shape of the second lumen 7 are preferably circular, oval, elliptical, or egg-shaped.

[0029] The shaft 2 may be formed with substantially the same outer diameter along its entire longitudinal direction, or it may be formed so that the outer diameter differs between a part of the longitudinal direction and other parts. For example, the outer diameter of the shaft 2 may differ between the distal and proximal parts of the shaft 2. The inner and outer diameters of the first tube 3 and / or the second tube 6 may also differ between the distal and proximal parts of the shaft 2.

[0030] In one embodiment, it is preferable that the outer diameter of the shaft 2 at its proximal end is larger than the outer diameter of the shaft 2 at its distal end. In this case, the shaft 2 may be formed such that the outer diameter of the first tube 3 at its proximal end is larger than the outer diameter of the first tube 3 at its distal end, or the outer diameter of the second tube 6 at its proximal end is larger than the outer diameter of the second tube 6 at its distal end, or both. Furthermore, the shaft 2 may be formed such that the outer diameter of the protective tube 9 at its proximal end is larger than the outer diameter of the protective tube 9 at its distal end, or the protective tube 9 may not be provided at the distal end of the shaft 2, but only at its proximal end. By configuring the shaft 2 in this way, it becomes easier to insert the distal end of the shaft 2 deeper into the bile duct while ensuring the rigidity of the proximal end of the shaft 2.

[0031] The shaft 2 may be configured such that the inner diameter of the first tube 3 at the proximal end of the shaft 2 is larger than the inner diameter of the first tube 3 at the distal end of the shaft 2, or the inner diameter of the second tube 6 at the proximal end of the shaft 2 is larger than the inner diameter of the second tube 6 at the distal end of the shaft 2, or both. With the shaft 2 configured in this way, the lavage fluid can be discharged more effectively, or bile can be aspirated.

[0032] The shaft 2, or the first tube 3, second tube 6, and protective tube 9 that constitute the shaft 2, can be made of resin. Examples of resins include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as polyethylene terephthalate, aromatic polyether ketone resins such as PEEK, polyether polyamide resins, polyurethane resins, polyimide resins, polyamide-imide resins, fluororesins such as PTFE, PFA, and ETFE, polyvinyl chloride resins, and silicone resins.

[0033] The shaft 2, the first tube 3, the second tube 6, and the protective tube 9 may be composed of a single layer or multiple layers. The shaft 2, the first tube 3, the second tube 6, and the protective tube 9 may have a portion of their longitudinal direction composed of a single layer, while other parts are composed of multiple layers.

[0034] The shaft 2, the first tube 3, the second tube 6, and the protective tube 9 may have a reinforcing layer. The reinforcing layer can increase the rigidity of the shaft 2. Preferably, the reinforcing layer is placed between an inner layer and an outer layer made of resin.

[0035] The reinforcing layer can be made of metal wires, fibers, etc. Examples of materials for the metal wires include stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy. Stainless steel is preferred among these. The metal wire may be a single wire or a stranded wire. Examples of fibers include polyarylate fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, PBO fibers, and carbon fibers. The fibers may be monofilaments or multifilaments.

[0036] The shape of the reinforcing layer is not particularly limited, but helical, mesh-like, and braided shapes are preferred. Among these, a braided shape is more preferred because it can effectively increase the rigidity of the shaft 2.

[0037] The shaft 2 is configured such that the liquid discharge port 5 is located distal to the liquid suction port 8. This allows the liquid discharge port 5 to be located at the tip of the shaft 2, making it easier to insert it deeper into the bile duct for irrigation and aspiration. Since the liquid discharge port 5 is formed at the distal end of the first lumen 4, the irrigation fluid that has been transported through the first lumen 4 to its distal end is discharged distally from the liquid discharge port 5, making it possible to irrigate the inside of the bile duct distal to the liquid discharge port 5. In addition, bile is relatively viscous, and bacterial-infected bile is even more viscous. By discharging the irrigation fluid into the bile duct from the liquid discharge port 5, the bile accumulated in the bile duct is diluted, and its viscosity can be reduced. On the other hand, the liquid suction port 8 is located proximal to the liquid discharge port 5, which makes it easier to aspirate bile accumulated in the bile duct. That is, because the liquid suction port 8 is located proximal to the liquid discharge port 5, it becomes easier to aspirate bile that has been diluted by the irrigation fluid and has reduced viscosity from the liquid suction port 8. Therefore, it becomes easier to aspirate bile from the liquid aspirator port 8, and the aspirated bile is less likely to clog the second lumen 7.

[0038] The liquid discharge port 5 is preferably located at least 3 mm distal to the liquid suction port 8, more preferably at least 4 mm, even more preferably at least 5 mm, preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 15 mm or less. By positioning the liquid discharge port 5 and the liquid suction port 8 in this manner, the aspiration of undiluted bile is suppressed, and it becomes easier to aspirate bile diluted with the washing solution. In addition, it becomes easier to aspirate bile accumulated deep inside the bile duct, and the amount of bile left behind can be reduced. The separation distance between the liquid discharge port 5 and the liquid suction port 8 is determined by measuring the longitudinal separation distance between the proximal end of the liquid discharge port 5 and the distal end of the liquid suction port 8.

[0039] When discharging the lavage solution into the bile duct from the liquid outlet 5 to cleanse the inside of the bile duct, it is desirable that the lavage solution be discharged so that it reaches further distally from the liquid outlet 5. This makes it easier to clean deep inside the bile duct. On the other hand, bile is relatively viscous and tends to adhere to the inner wall of the bile duct. Therefore, when the lavage solution is discharged from the liquid outlet 5, it is desirable that the lavage solution discharged from the liquid outlet 5 washes away the bile adhering to the inner wall of the bile duct. From this viewpoint, the first lumen 4 has a constriction portion 14 at its distal end, and the cross-sectional area of ​​the first lumen 4 at the constriction portion 14 is formed to be narrower than its distal and proximal sides. By forming the distal end of the first lumen 4 in this way, the lavage solution can be discharged while spreading radially toward the distal side from the liquid outlet 5. This makes it possible to clean deeper inside the bile duct and makes it easier to wash away the bile adhering to the inner wall of the bile duct.

[0040] In the throttling section 14, the cross-sectional area of ​​the first lumen 4 (specifically, the cross-sectional area perpendicular to the longitudinal direction of the first lumen 4) is formed to be narrower than the cross-sectional area of ​​the first lumen 4 on its distal and proximal sides. The cross-sectional shape of the first lumen 4 in the throttling section 14 is not particularly limited and can be circular, elliptical, oblong, egg-shaped, polygonal, irregular, etc. Among these, the cross-sectional shape of the first lumen 4 in the throttling section 14 is preferably circular, elliptical, or oblong, and more preferably circular. This makes it easier for the cleaning liquid to be discharged from the liquid discharge port 5 so that it spreads radially over the entire circumferential direction of the liquid discharge port 5.

[0041] The inner diameter of the first lumen 4 in the diaphragm 14 may be narrower than the inner diameters of the distal and proximal first lumens 4 throughout its entire circumferential direction, or it may be narrower than the inner diameters of the distal and proximal first lumens 4 in only a portion of its circumferential direction. Preferably, the inner diameter of the first lumen 4 in the diaphragm 14 is narrower than the inner diameters of the distal and proximal first lumens 4 throughout its entire circumferential direction. In other words, it is preferable that the cross-sectional size of the first lumen 4 is narrower throughout its entire circumferential direction in the diaphragm 14.

[0042] The distal end of the first lumen 4 where the throttling portion 14 is provided is preferably the portion of the first lumen 4 that is proximal to the liquid discharge port 5 and distal to the liquid suction port 8. Therefore, it is preferable that the throttling portion 14 is formed as the distal end of the first lumen 4, proximal to the liquid discharge port 5 and distal to the liquid suction port 8. Note that "proximal to the liquid discharge port 5 and distal to the liquid suction port 8" means the portion that is proximal to the proximal end of the liquid discharge port 5 and distal to the distal end of the liquid suction port 8. Furthermore, the throttling portion 14 means the portion of the distal end of the first lumen 4 with the narrowest cross-sectional area. By forming the throttling portion 14 in this way, the cleaning liquid is more easily discharged distally from the liquid discharge port 5 while spreading radially. The throttling portion 14 is also preferably located at least 1 mm proximal to the liquid outlet 5 (specifically, the proximal end of the liquid outlet 5), more preferably at least 2 mm, more preferably 15 mm or less, more preferably 12 mm or less, and even more preferably 10 mm or less.

[0043] The first lumen 4 can be formed such that its cross-sectional area gradually narrows from the proximal and / or distal side of the throttling section 14 toward the throttling section 14. For example, as shown in Figure 4, the first lumen 4 may have a narrowing section 15 on the proximal side of the throttling section 14 where the inner diameter of the first lumen 4 narrows from the proximal side toward the distal side, and an expanding section 16 on the distal side of the throttling section 14 where the inner diameter of the first lumen 4 widens from the proximal side toward the distal side. In the narrowing section 15, the inner diameter of the first lumen 4 may narrow continuously or narrow in stages. In the expanding section 16, the inner diameter of the first lumen 4 may widen continuously or widen in stages. By forming the distal end of the first lumen 4 in this way, the cleaning fluid can pass through the throttling section 14 more smoothly, and the pressure loss when the cleaning fluid passes through the throttling section 14 can be reduced. Therefore, it becomes easier to forcefully discharge the cleaning solution distally from the liquid discharge port 5. In this case, the longitudinal lengths of the reduced diameter section 15 and the expanded diameter section 16 are preferably 1 mm or more, more preferably 2 mm or more, preferably 12 mm or less, and more preferably 10 mm or less.

[0044] The first lumen 4 may not have a narrowed diameter section 15 or a widened diameter section 16 (see Figure 5). That is, the cross-sectional area of ​​the first lumen 4 may be abruptly narrowed at the constricted section 14, and the cross-sectional area of ​​the first lumen 4 may be narrowed only at the constricted section 14 at the distal end of the first lumen 4. By forming the distal end of the first lumen 4 in this way, turbulence is more likely to occur when the washing fluid passes through the constricted section 14, and when the washing fluid is discharged from the liquid outlet 5 in this state, bile adhering to the inner wall of the bile duct is more easily washed away.

[0045] The aperture portion 14 may be formed with a certain length in the longitudinal direction, or it may have substantially no length in the longitudinal direction and be formed at a single point in the longitudinal direction. For example, if the first lumen 4 has a reduced diameter section 15 and a widened diameter section 16, the aperture portion 14 can be formed at a single point in the longitudinal direction. The longitudinal length of the aperture portion 14 is preferably 8 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

[0046] The cross-sectional area of ​​the first lumen 4 in the constriction section 14 is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less, of the cross-sectional area of ​​the portion of the first lumen 4 proximal to the constriction section 14 that is not narrowed. This allows the lavage fluid to reach deeper into the bile duct and facilitates the discharge of the lavage fluid distally from the liquid outlet 5 while spreading radially. On the other hand, the cross-sectional area of ​​the first lumen 4 in the constriction section 14 is preferably 10% or more, more preferably 20% or more, and even more preferably 25% or more, of the cross-sectional area of ​​the portion of the first lumen 4 proximal to the constriction section 14 that is not narrowed. This reduces the pressure loss when the lavage fluid passes through the constriction section 14 and makes it easier to forcefully discharge the lavage fluid distally from the liquid outlet 5. Note that the portion of the first lumen 4 proximal to the aperture 14 where the cross-sectional area is not narrowed refers to the portion proximal to the reduced diameter section 15 when a reduced diameter section 15 is provided proximal to the aperture 14, as shown in Figure 4, and to the portion proximal to the aperture 14 when a reduced diameter section 15 is not provided proximal to the aperture 14, as shown in Figure 5. The cross-sectional area of ​​the portion of the first lumen 4 where the cross-sectional area is not narrowed can be measured, for example, in Figure 4, by measuring the cross-sectional area of ​​the portion within 10 mm proximal to the reduced diameter section 15, and in Figure 5, by measuring the cross-sectional area of ​​the portion within 10 mm proximal to the aperture 14.

[0047] One method for forming the constricted portion 14 is to prepare a cylindrical mold having an inner surface shape corresponding to the outer surface shape of the first tube 3 and a rod-shaped member having an outer surface shape corresponding to the inner surface shape of the constricted portion 14 of the first tube 3, place the rod-shaped member in the lumen of the cylindrical mold, insert a resin tube into the space between the cylindrical mold and the rod-shaped member and heat and melt it to form an inner surface shape in the lumen of the resin tube that corresponds to the outer surface shape of the rod-shaped member. The constricted portion 14 can also be formed by fitting a ring member into the lumen of the resin tube.

[0048] The distal end of the first tube 3, where the first lumen 4 is formed, preferably has a tapered portion 17 whose outer diameter decreases toward the distal end. That is, distal to the liquid aspiration port 8, the shaft 2 preferably has a tapered portion 17 whose outer diameter decreases toward the distal end. This shape of the tip of the shaft 2 makes it easier to insert the shaft 2 into the bile duct. The tapered portion 17 may be formed by processing the shaft 2 to become narrower, or a separate member with a tapered shape may be attached to the tip of the shaft 2.

[0049] The outer edge of the liquid outlet 5 is preferably formed to extend perpendicular to the longitudinal direction. Furthermore, the outer edge of the liquid outlet 5 is preferably chamfered or rounded in a side view. If the outer edge of the liquid outlet 5 is formed in this way, it becomes less likely to damage the bile duct when inserting the shaft 2 into the bile duct.

[0050] In a cross-section perpendicular to the longitudinal direction of the shaft 2, the cross-sectional area of ​​the first lumen 4 is preferably smaller than the cross-sectional area of ​​the second lumen 7 (see Figure 6). This makes it easier to forcefully discharge the cleaning fluid from the liquid outlet 5 of the first lumen 4, making it easier to clean deeper into the bile duct. Also, when aspirating bile from the liquid suction port 8 of the second lumen 7, clogging of the second lumen 7 is less likely to occur. The cross-sectional area of ​​the first lumen 4 (specifically, the cross-sectional area of ​​the part of the first lumen 4 where the cross-sectional area is not narrowed) is preferably 0.9 times or less, more preferably 0.8 times or less, more preferably 0.2 times or more, and more preferably 0.3 times or more than the cross-sectional area of ​​the second lumen 7. Note that in Figure 6, there is a gap between the protective tube 9 and the first tube 3 and the second tube 6, but there does not need to be a gap between the protective tube 9 and the first tube 3 and the second tube 6. For example, after placing the first tube 3 and the second tube 6 inside the lumen of the protective tube 9, a heat-shrinkable tube can be placed over the outside and heat-processed to create a gap between the protective tube 9 and the first tube 3 and the second tube 6.

[0051] The liquid aspiration port 8 is preferably formed in an inclined shape. Specifically, the outer edge of the liquid aspiration port 8 has an inclined portion, and the distal end of the inclined portion is preferably located closer to the first lumen 4 than the proximal end of the inclined portion. When the liquid aspiration port 8 is formed in this way, the size of the liquid aspiration port 8 can be made wider, making it easier to aspirate bile. In addition, by having the distal end of the inclined portion located closer to the first lumen 4 than the proximal end of the inclined portion, it becomes easier to aspirate bile that is proximal to the liquid aspiration port 8. The outer edge of the liquid aspiration port 8 may be formed in a straight line or a non-straight line.

[0052] The outer edge of the liquid suction port 8 has a linearly formed inclined portion, and notches or protrusions may be formed in this inclined portion. Specifically, when the side of the shaft 2 on which the second tube 6 is located is considered the upper side and the side on which the first tube 3 is located is considered the lower side, the outer edge of the liquid suction port 8 is linearly inclined distally from the upper side to the lower side in the inclined portion, and notches or protrusions may be formed in this inclined portion. Either a notch or a protrusion may be formed in the inclined portion, or both may be formed. If the outer edge of the liquid suction port 8 is formed in this way, it becomes less likely that gallstones will become lodged in the liquid suction port 8 or that the liquid suction port 8 will be blocked by gallstones when bile is aspirated from the liquid suction port 8.

[0053] Figure 7 shows an example in which a notch is provided on the outer edge of the liquid suction port 8. In Figure 7, the outer edge of the liquid suction port 8 has a linearly formed inclined portion 18, and a notch 19 is formed in the inclined portion 18. In the inclined portion 18, the outer edge of the liquid suction port 8 is formed to coincide with a hypothetical straight line connecting the upper and lower ends of the liquid suction port 8, and in the notch 19, the outer edge of the liquid suction port 8 is located proximal to the hypothetical straight line. If a protrusion is formed in the inclined portion 18, in the protrusion, the outer edge of the liquid suction port 8 is located distal to the hypothetical straight line connecting the upper and lower ends of the liquid suction port 8.

[0054] The liquid discharged from the liquid discharge port 5, i.e., the irrigation solution, is preferably physiological saline. This allows the bile in the bile duct to be diluted with physiological saline while being aspirated from the liquid suction port 8, thereby effectively irrigating the bile duct. For example, if there is infected bile in the bile duct, irrigating the bile duct can suppress the formation of gallstones and bile stasis.

[0055] The discharge of the lavage solution from the liquid discharge port 5 and the aspiration of bile from the liquid aspirator port 8 may be performed at the same time, at different times, or alternately. By lavaging the bile duct in this way, bile can be efficiently aspirated from the bile duct, and the internal pressure of the bile duct can be prevented from becoming excessively high. Therefore, the occurrence of sepsis caused by infected bile flowing through the liver into the blood vessels throughout the body can be suppressed.

[0056] Using saline solution as a lavage solution allows for efficient bile aspiration due to the difference in specific gravity between saline and bile. During endoscopic retrograde cholangiopancreatography (ERCP), the patient is usually placed prone or left lateral decubitus. In this position, the opening of the bile duct is located above the inside of the bile duct. When catheter 1 is used in this position and saline solution is discharged from liquid outlet 5, saline solution has a lower specific gravity than bile. Therefore, when saline solution flows deep into the bile duct, it rises as a supernatant, efficiently mixing and diluting the bile. As a result, the diluted bile can be efficiently removed from the bile duct by aspirating it from liquid aspirator 8.

[0057] Contrast agent may be discharged from the liquid outlet 5. For example, after flushing the bile duct with saline solution, injecting contrast agent into the bile duct from the liquid outlet 5 makes it easier to perform imaging diagnosis of the bile duct.

[0058] The shaft 2 may contain a radiopaque material to facilitate its position under X-ray fluoroscopy. Examples of radiopaque materials include lead, barium, iodine, tungsten, gold, platinum, iridium, platinum-iridium alloy, stainless steel, titanium, cobalt-chromium alloy, palladium, and tantalum. For example, it is preferable to provide radiopaque markers at the proximal and distal ends of the shaft 2, thereby allowing the position of the shaft 2 within the body cavity to be confirmed under X-ray fluoroscopy.

[0059] The shaft 2 may have its outer surface coated with a hydrophilic polymer. This facilitates insertion of the shaft 2 into the forceps channel from the forceps channel of the endoscope. Examples of hydrophilic polymers include polyethylene glycol, poly-2-hydroxyethyl methacrylate, polyacrylamide, polyvinylpyrrolidone, and maleic anhydride copolymers such as methyl vinyl ether maleic anhydride copolymer. [Explanation of symbols]

[0060] 1: Bile aspiration catheter 2: Shaft 3: First tube 4: First Lumen 5:Liquid outlet 6: Second tube 7: Second Lumen 8:Liquid suction port 9: Protective tube 10: Hub 11: Supply connection port 12: Suction connection port 13: Guide wire port 14: Aperture section 15: Reduced diameter section 16: Widening section 17: Tapered section 18: Inclined part 19: Notch

Claims

1. A catheter for inserting into the bile duct to aspirate bile, A shaft extending longitudinally from the proximal to the distal side, A first lumen is provided on the shaft, extending in the longitudinal direction and having a liquid discharge port at its distal end, The shaft is provided with a second lumen that extends in the longitudinal direction and has a liquid suction port at its distal end, The liquid discharge port is located distal to the liquid suction port and at the tip of the shaft. A bile aspiration catheter in which the first lumen has a constriction at its distal end, and the cross-sectional area of ​​the first lumen at the constriction is formed to be narrower than that of its distal and proximal sides.

2. The bile aspiration catheter according to claim 1, wherein the constriction portion is formed proximal to the liquid discharge port and distal to the liquid suction port.

3. The bile aspiration catheter according to claim 1 or 2, wherein the first lumen has a narrowing section on the proximal side of the constriction where the inner diameter of the first lumen narrows from the proximal side to the distal side, and an expanding section on the distal side of the constriction where the inner diameter of the first lumen widens from the proximal side to the distal side.

4. The bile aspiration catheter according to any one of claims 1 to 3, wherein the shaft has a tapered portion distal to the liquid aspiration port, with the outer diameter decreasing toward the distal end.

5. The bile aspiration catheter according to any one of claims 1 to 4, wherein in a cross section perpendicular to the longitudinal direction of the shaft, the cross-sectional area of ​​the first lumen is smaller than the cross-sectional area of ​​the second lumen.

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