Bile aspiration catheter

Abstract

To provide a bile aspiration catheter capable of optimally aspirating bile by preventing the bile aspiration from being easily obstructed by a gallstone when aspirating the bile in a bile duct.SOLUTION: A bile aspiration catheter comprises a shaft 2 extending in a longitudinal direction, where the shaft 2 includes a first tube 3 having a liquid discharge port 5 at a distal end and a second tube 6 having a liquid aspiration port 8 at the distal end, and the liquid aspiration port 8 is located on a proximal side with respect to the liquid discharge port 5. A distal-side edge 21 of the second tube 6 has an upper end located on the proximal side with respect to a lower end, in a site not overlapping with a lumen of the second tube 6 in a side view of the shaft 2, the distal-side edge 21 of the second tube 6 is formed in a linear shape of connecting the upper end and the lower end of the distal-side edge 21, and in at least a part of a site overlapping with a lumen of the second tube 6, has a portion located on the proximal side and / or the distal side with respect to a virtual straight line of connecting the upper end and the lower end of the distal-side edge 21.SELECTED DRAWING: Figure 2

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 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 cholangiography 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 thin-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 thin-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 thin-diameter straight body portion is 20 to 80% of the outer diameter of the main body portion, and the length of the thin-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 project] [Problems that the invention aims to solve]

[0005] When aspirating bile from the bile duct using a catheter, it is desirable that suction is not obstructed by gallstones, and that gallstones do not block the suction port of the catheter. The present invention has been made in view of the above circumstances, and its purpose is to provide a bile aspirator that allows for suitable bile aspiration without obstruction by gallstones when aspirating bile from 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 inserting it into the bile duct, having a shaft that extends longitudinally from the proximal to the distal side, wherein the shaft has a first tube having a liquid discharge port at its distal end and a second tube arranged alongside the first tube and having a liquid aspiration port at its distal end, the liquid aspiration port being located proximal to the liquid discharge port, the shaft has an upper side where the second tube is located and a lower side where the first tube is located, the distal end edge of the second tube has an upper end located proximal to the lower end, and in a side view from a direction perpendicular to the longitudinal and vertical directions of the shaft, the distal end edge of the second tube is formed in a straight line connecting the upper and lower ends of the distal end edge in the portion that does not overlap with the lumen of the second tube, and at least a portion of the portion that overlaps with the lumen of the second tube has a portion that is located proximal and / or distal to the imaginary straight line connecting the upper and lower ends of the distal end edge.

[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, the distal end edge of the second tube is formed, making it difficult for gallstones to become lodged in the liquid aspiration port, and thus reducing the likelihood of the liquid aspiration port being blocked by gallstones. Furthermore, even if gallstones are present in a way that blocks the liquid aspiration port from the distal side, bile can be easily drawn into the lumen of the second tube through the gap at the distal end edge of the second tube. Therefore, bile accumulated in the bile duct can be effectively aspirated.

[0008] In a side view of the shaft, the distal end edge of the second tube may be configured such that, in the portion overlapping with the lumen of the second tube, it has a portion located proximal to the imaginary straight line and no portion located distal to the imaginary straight line. In a side view of the shaft, the distal end edge of the second tube may be configured such that, in the portion overlapping with the lumen of the second tube, it has a portion located distal to the imaginary straight line and no portion located proximal to the imaginary straight line. In a side view of the shaft, the distal end edge of the second tube may be configured such that, in the portion overlapping with the lumen of the second tube, it has a portion located proximal to the imaginary straight line and a portion located distal to the imaginary straight line.

[0009] In a cross-section perpendicular to the longitudinal direction of the shaft, it is preferable that the cross-sectional area of ​​the lumen of the second tube is larger than that of the lumen of the first tube. This makes it less likely for the lumen of the second tube to become blocked when aspirating bile. In addition, it becomes easier to forcefully discharge the lavage solution from the liquid outlet of the first tube, making it easier to lavage deeper into the bile duct. [Effects of the Invention]

[0010] The bile aspiration catheter of the present invention is less likely to be blocked by gallstones. Therefore, it is possible to effectively aspirate bile accumulated in the bile duct. [Brief explanation of the drawing]

[0011] [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 side view of the second tube at the distal end of the bile aspiration catheter. [Figure 5] This figure shows an auxiliary side view of the second tube at the distal end of the bile aspiration catheter shown in Figure 4. [Figure 6] Figure 4 shows a modified side view of the second tube at the distal end of the bile aspiration catheter. [Figure 7] Figure 4 shows a modified side view of the second tube at the distal end of the bile aspiration catheter. [Figure 8] Figure 1 shows a cross-sectional view of the bile aspiration catheter from point VIII to VIII. [Modes for carrying out the invention]

[0012] 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.

[0013] A bile aspiration catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 8. Figure 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. Figures 2 and 3 show a side view and a perspective view of the distal end of the bile aspiration catheter shown in Figure 1, respectively. Figure 8 shows a VIII-VIII cross-sectional view of the bile aspiration catheter shown in Figure 1. Figures 4 to 7 show a side view of the second tube at the distal end of the bile aspiration catheter shown in Figure 2 and a modified example thereof.

[0014] The bile aspiration catheter 1 is a catheter used to aspirate bile by inserting it into the bile duct. The bile aspiration catheter 1 of the present invention can aspirate bile accumulated in the bile duct while supplying liquid into the bile duct to flush it. Hereinafter, the bile aspiration catheter will be simply referred to as "catheter".

[0015] Catheter 1 has a shaft 2 that extends in the longitudinal direction. In catheter 1, the longitudinal direction is determined based on the direction of extension of shaft 2. Catheter 1 has a proximal side and a distal side, which are the sides of the longitudinal direction. The proximal side refers to the direction toward the user of catheter 1, i.e., the operator's proximal side, and the distal side refers to the opposite direction of the proximal side, i.e., the direction toward the target of treatment. Shaft 2 has a radial direction, which is perpendicular to the longitudinal direction. In Figure 1, the right side of the figure corresponds to the proximal side, and the left side of the figure corresponds to the distal side.

[0016] The shaft 2 comprises a first tube 3 having a liquid discharge port 5 at its distal end and a second tube 6 having a liquid suction port 8 at its distal end. The first tube 3 and the second tube 6 each extend longitudinally and are arranged side by side radially. The first tube 3 has a first lumen 4 as a longitudinally extending internal lumen, and the second tube 6 has a second lumen 7 as a longitudinally extending internal lumen. Preferably, the first tube 3 and the second tube 6 are welded or bonded together to form a single unit, or the first tube 3 and the second tube 6 are placed in the lumen of a protective tube 9, and the protective tube 9 integrates the first tube 3 and the second tube 6.

[0017] When using the catheter 1, a liquid (washing liquid) to be supplied into the bile duct flows through the first lumen 4 of the first tube 3, and the liquid is discharged into the bile duct from the liquid discharge port 5 at the distal end of the first tube 3. Therefore, the first tube 3 preferably has a proximal opening, and a liquid supply part is preferably provided in communication with the proximal opening of the first tube 3. Examples of the liquid supply part include a syringe and a pump.

[0018] Bile and the like accumulated in the bile duct are sucked from the liquid suction port 8 at the distal end of the second tube 6 and discharged from the bile duct through the second lumen 7 of the second tube 6. Therefore, the second tube 6 preferably has a proximal opening, and a liquid suction part is preferably provided in communication with the proximal opening of the second tube 6. Examples of the liquid suction part include a syringe and a pump. As the syringe of the liquid suction part, a backlock syringe may be used.

[0019] The first lumen 4 can also serve as a guide wire lumen. By having the first lumen 4 also serve as a guide wire lumen, the outer diameter of the shaft 2 can be reduced. In addition, bile can be sucked or the bile duct can be washed without removing the guide wire, leading to simplification of the procedure and shortening of the operation time.

[0020] Preferably, a hub 10 is provided on the proximal side of the shaft 2. The hub 10 has a supply connection port 11 communicating with the first lumen 4 and a suction connection port 12 communicating with the second lumen 7. Preferably, the liquid supply part is connected to the supply connection port 11 of the hub 10, and the liquid suction part 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The first tube 3, the second tube 6, and the protective tube 9 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.

[0031] The first tube 3, the second tube 6, and the protective tube 9 may be composed of a single layer or multiple layers. 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 and other portions composed of multiple layers.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The shaft 2 is configured such that the liquid suction port 8 is located proximal to the liquid discharge port 5. 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 tube 3, the irrigation fluid that has been transported to the distal end of the first tube 3 through the first lumen 4 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 positioning of the liquid suction port 8 proximal to the liquid discharge port 5 makes it easier to aspirate the bile accumulated in the bile duct. That is, by positioning the liquid suction port 8 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.

[0036] The liquid suction port 8 is preferably located at least 3 mm proximal to the liquid discharge port 5, 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 suction port 8 and liquid discharge port 5 in this manner, the aspiration of undiluted bile is suppressed, and it becomes easier to aspirate bile diluted with the lavage 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 suction port 8 and the liquid discharge port 5 is determined by measuring the longitudinal separation distance between the distal end of the liquid suction port 8 and the proximal end of the liquid discharge port 5.

[0037] When inserting the shaft 2 into the bile duct and aspirating bile from the liquid aspiration port 8, it is desirable that gallstones do not become lodged in the liquid aspiration port 8 or that the liquid aspiration port 8 is not blocked by gallstones. From this perspective, the distal end edge 21 of the second tube 6 that forms the liquid aspiration port 8 is formed in a non-linear shape when viewed from the side of the shaft 2. Specifically, when the side of the shaft 2 where the second tube 6 is located is considered the upper side and the side where the first tube 3 is located is considered the lower side, the distal end edge 21 of the second tube 6 is formed such that the upper end 21A is located proximal to the lower end 21B. Furthermore, as shown in Figures 4 to 7, in a side view of the shaft 2, the distal end edge 21 of the second tube 6 is formed in a straight line connecting the upper end 21A and the lower end 21B of the distal end edge 21 in the portion 22 that does not overlap with the lumen of the second tube 6, i.e., the second lumen 7. At least a portion of the portion 23 that overlaps with the lumen of the second tube 6, i.e., the second lumen 7, is formed to have a portion that is located proximal and / or distal to the imaginary straight line 24 connecting the upper end 21A and the lower end 21B of the distal end edge 21. In Figures 4 and 5, in the portion 23 overlapping with the second lumen 7, the distal edge 21 of the second tube 6 is formed to have a portion located proximal to the virtual straight line 24. In Figure 6, in the portion 23 overlapping with the second lumen 7, the distal edge 21 of the second tube 6 is formed to have a portion located distal to the virtual straight line 24. In Figure 7, in the portion 23 overlapping with the second lumen 7, the distal edge 21 of the second tube 6 is formed to have portions located both proximal and distal to the virtual straight line 24.

[0038] Note that the side view of shaft 2 refers to the plan view of shaft 2 when viewed from a direction perpendicular to the longitudinal and vertical directions. Figures 4 to 7 show a side view of shaft 2. In addition, the portion 22 in the side view of shaft 2 where the distal end edge 21 of the second tube 6 does not overlap with the second lumen 7 is the upper end (including the upper end 21A) and lower end (including the lower end 21B) of the distal end edge 21, and the portion 23 in the side view of shaft 2 where the distal end edge 21 of the second tube 6 overlaps with the second lumen 7 is the portion between the upper end and lower end of the distal end edge 21.

[0039] The distal end edge 21 of the second tube 6 is formed such that its upper end 21A is located proximal to its lower end 21B, which allows for a wider liquid aspiration port 8 and makes bile aspiration easier. Furthermore, the distal end edge 21 of the second tube 6 extends distally from the upper end 21A to the lower end 21B, and at least a portion of the part 23 that overlaps with the second lumen 7 is formed to protrude distally or recess proximally, making it difficult for gallstones to become lodged in the liquid aspiration port 8. Even if a gallstone does become lodged in the liquid aspiration port 8, it is less likely that the gallstone will completely block the liquid aspiration port 8. In particular, the distal end edge 21 of the second tube 6 is formed with a straight upper end and a straight lower end, while the portion in between is formed in a non-linear shape, protruding distally or recessed proximally. As a result, the direction of extension of the distal end edge 21 changes significantly near the boundary between these straight and non-linear portions, making it less likely for gallstones to become lodged in the liquid aspiration port 8 or to block the liquid aspiration port 8.

[0040] Preferably, the distal edge 21 is formed in a straight line connecting the upper end 21A and the lower end 21B in the portion 22 that does not overlap with the second lumen 7, and further in a straight line connecting the upper end 21A and the lower end 21B in a part of the portion 23 that overlaps with the second lumen 7. That is, preferably, the distal edge 21 is formed in a straight line connecting the upper end 21A and the lower end 21B from the portion 22 that does not overlap with the second lumen 7 in a side view of the shaft 2 to a part of the portion 23 that overlaps with the second lumen 7. Hereinafter, the portion of the distal edge 21 that includes the upper end 21A and the lower end 21B, and is formed in a straight line connecting the upper end 21A and the lower end 21B, will be referred to as the "straight edge portion". Also, the portion of the distal edge 21 between the straight edge portion on the upper end 21A side and the straight edge portion on the lower end 21B side, that is, the portion located proximal and / or distal to the imaginary straight line 24, will be referred to as the "uneven edge portion". The uneven edges may consist only of recesses or only of protrusions.

[0041] The angle between the imaginary straight line 24 connecting the upper end 21A and the lower end 21B of the distal edge 21 and the longitudinal direction of the shaft 2 is preferably 10° or more, more preferably 20° or more, and preferably 75° or less, and more preferably 70° or less. By forming the distal edge 21 in this way, the size of the liquid aspiration port 8 can be made wider, and bile located distal to the liquid aspiration port 8 can be easily aspirated.

[0042] As shown in Figures 4 and 5, in a side view of the shaft 2, when the length of the imaginary straight line 24 connecting the upper end 21A and the lower end 21B of the distal edge 21 (specifically, the length between the upper end 21A and the lower end 21B of the imaginary straight line 24) is L1, and the length of the portion of the distal edge 21 that overlaps with the imaginary straight line 24, i.e., the straight edge portion, is L2, the value of L2 / L1 is preferably 0.1 or greater, more preferably 0.2 or greater, preferably 0.7 or less, and more preferably 0.6 or less. By forming the distal edge 21 in this way, it becomes less likely for gallstones to become lodged in the liquid aspiration port 8.

[0043] In a side view of the shaft 2, the shape of the uneven edge portion 21Z is not particularly limited. Examples of the shape of the uneven edge portion 21Z include an arc shape, an ellipse or an oblong shape with part of it removed, a polygon with one side removed, a polygon with rounded corners and one side removed, and shapes that combine these.

[0044] In a side view of the shaft 2, when the length of the imaginary straight line 24 between the two ends of the uneven edge portion 21Z of the distal end edge 21 is L3, and the length from the imaginary straight line 24 to the point where the uneven edge portion 21Z is furthest distal or proximal to the imaginary straight line 24 is L4, the value of L4 / L3 is preferably 0.3 or more, more preferably 0.5 or more, preferably 1.5 or less, and more preferably 1.2 or less. The formation of the distal end edge 21 in this manner makes it difficult for gallstones to become lodged in the liquid aspiration port 8. In addition, the distal end edge 21 becomes less prone to distortion, making it easier to suitably aspirate bile from the liquid aspiration port 8. Note that the length L3 corresponds to the length L1 of the imaginary straight line 24 connecting the upper end 21A and the lower end 21B of the distal end edge 21 minus the length L2 of the straight edge portion.

[0045] The distal edge 21 preferably forms an angle at the boundary between the straight edge portion and the uneven edge portion 21Z. In other words, the distal edge 21 is preferably formed by a bend rather than being rounded at the boundary between the straight edge portion and the uneven edge portion 21Z. This formation of the distal edge 21 makes it less likely for gallstones to become lodged in the liquid aspiration port 8.

[0046] As one embodiment, as shown in Figures 4 and 5, in a side view of the shaft 2, it is preferable that the distal end edge 21 of the second tube 6 has a portion located proximal to the virtual straight line 24 in the portion 23 that overlaps with the second lumen 7, and does not have a portion located distal to the virtual straight line 24. By forming the distal end edge 21 in this way, it becomes easier to aspirate not only bile distal to the liquid aspiration port 8, but also bile proximal to the liquid aspiration port 8. Furthermore, even if gallstones are present blocking the liquid aspiration port 8 from the distal side, bile can be easily drawn into the second lumen 7 through the gap in the recessed edge portion 21Z that is recessed proximal to the virtual straight line 24.

[0047] As shown in Figure 6, in a side view of the shaft 2, the distal end edge 21 of the second tube 6 may be formed such that, in the portion 23 overlapping with the second lumen 7, it has a portion located distal to the virtual straight line 24 and no portion located proximal to the virtual straight line 24. If the distal end edge 21 is formed in this way, gallstones are less likely to become lodged in the liquid aspiration port 8. Also, when a gallstone hits the distal end edge 21 along the flow aspirated from the liquid aspiration port 8, the gallstone is more likely to be repelled away from the liquid aspiration port 8.

[0048] As shown in Figure 7, in a side view of the shaft 2, the distal end edge 21 of the second tube 6 may be formed such that, in the portion 23 overlapping with the second lumen 7, it has both a portion located proximal to the imaginary straight line 24 and a portion located distal to it. Even if the distal end edge 21 is formed in this way, gallstones are less likely to become lodged in the liquid aspiration port 8. Furthermore, it becomes easier to aspirate not only bile distal to the liquid aspiration port 8, but also bile proximal to the liquid aspiration port 8.

[0049] In a cross-section perpendicular to the longitudinal direction of shaft 2, the cross-sectional area of ​​the second lumen 7 is preferably larger than the cross-sectional area of ​​the first lumen 4 (see Figure 8). This makes it less likely for the second lumen 7 to become clogged when aspirating bile. It also makes it easier to forcefully discharge the lavage solution from the liquid outlet 5 of the first lumen 4, making it easier to lavage deeper into the bile duct. The cross-sectional area of ​​the second lumen 7 is preferably 1.1 times or more, more preferably 1.2 times or more, preferably 4.0 times or less, more preferably 3.0 times or less, and even more preferably 2.5 times or less than the cross-sectional area of ​​the first lumen 4. In Figure 8, 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.

[0050] As shown in Figures 2 and 3, it is preferable that the shaft 2 has a tapered portion 25 distal to the liquid suction port 8, where the outer diameter decreases towards 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 25 may be formed by machining the shaft 2 to narrow towards the end, or a separate member with a tapered shape may be attached to the tip of the shaft 2.

[0051] The outer edge of the liquid outlet 5, that is, the distal end edge of the first tube 3, 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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]

[0058] 1: Bile aspiration catheter 2: Shaft 3: First tube 4: First Lumen 5:Liquid outlet 6: Second tube 7: Second lumen (the inner lumen of the second tube) 8:Liquid suction port 9: Protective tube 10: Hub 11: Supply connection port 12: Suction connection port 13: Guide wire port 21: Distal end edge (of the second tube), 21A: Upper end, 21B: Lower end, 21Z: Uneven edge 22: The portion of the second tube that does not overlap with the lumen. 23: The part that overlaps with the lumen of the second tube 24: Virtual Line 25: Tapered section

Claims

1. A catheter having a shaft that extends longitudinally from the proximal to the distal end, for insertion into the bile duct to aspirate bile, The shaft comprises a first tube having a liquid discharge port at its distal end, and a second tube arranged alongside the first tube and having a liquid suction port at its distal end. The liquid suction port is located proximal to the liquid discharge port. The shaft has an upper side on which the second tube is disposed and a lower side on which the first tube is disposed. The distal end edge of the second tube is such that the upper end is located proximal to the lower end. In a side view from a direction perpendicular to the longitudinal and vertical directions of the shaft, the distal end edge of the second tube is formed in a straight line connecting the upper and lower ends of the distal end edge, from a portion that does not overlap with the lumen of the second tube to a portion that overlaps with the lumen of the second tube, and in other parts of the portion that overlaps with the lumen of the second tube, there are portions that are located proximal and / or distal to the imaginary straight line connecting the upper and lower ends of the distal end edge.

2. The bile aspiration catheter according to claim 1, wherein, in the side view of the shaft, the distal end edge of the second tube has a portion located proximal to the imaginary straight line in the portion overlapping with the lumen of the second tube, and no portion located distal to the imaginary straight line.

3. The bile aspiration catheter according to claim 1, wherein, in the side view of the shaft, the distal end edge of the second tube has a portion located distal to the imaginary straight line in the portion overlapping with the lumen of the second tube, and no portion located proximal to the imaginary straight line.

4. The bile aspiration catheter according to claim 1, wherein, in the side view of the shaft, the distal end edge of the second tube has a portion located proximal to the imaginary straight line and a portion located distal to the imaginary straight line in the portion that overlaps with the lumen of the second tube.

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 lumen of the second tube is greater than the cross-sectional area of ​​the lumen of the first tube.

6. The bile aspiration catheter according to any one of Claims 1 to 4, wherein when L1 is the length of the imaginary straight line connecting the upper and lower ends of the distal edge, and L2 is the length of the portion of the distal edge that overlaps with the imaginary straight line, the value of L2 / L1 is 0.2 or more and 0.7 or less.

7. In a side view of the shaft, the distal end edge of the second tube has a straight edge portion formed in a straight line connecting the upper and lower ends of the distal end edge from a portion that does not overlap with the lumen of the second tube to a portion that overlaps with the lumen of the second tube, and an uneven edge portion located proximal and / or distal to a virtual straight line connecting the upper and lower ends of the distal end edge in the other portion that overlaps with the lumen of the second tube, and an angle is formed at the boundary between the straight edge portion and the uneven edge portion, as described in any one of Claims 1 to 4.

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