Suction catheter and suction system

Abstract

Provided are: a suction catheter that can be inserted into a narrow biological lumen and can effectively suction a wide range; and a suction system.　This suction catheter (10) comprises: a deformable tubular distal end tip (23) comprising a distal end opening (32); and a base shaft (22) disposed on the proximal end side of the distal end tip (23) and comprising a proximal end opening (24) at the proximal end. The suction catheter (10) has a main body tube (20) in which a lumen (21) communicating from the distal end opening (32) to the proximal end opening (24) is formed. The cross-sectional shape of the inner peripheral surface of the distal end opening (32) has lengths in a first direction (Y) and a second direction (Z) perpendicular to the first direction (Y). A second length (L2) in the second direction (Z) is longer than a first length (L1) in the first direction (Y). The cross-sectional shape of the inner peripheral surface of the base shaft (22) is circular, and the distal end opening (32) can be deformed by inserting, into the lumen (21), a dilator (60) having an outer diameter that is longer than the first length (L1), shorter than the second length (L2), and equal to or less than the inner diameter of the base shaft (22).

Description

Suction catheter and suction system

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[0001] The present invention relates to a suction catheter and a suction system.

[0002] Currently, a suction catheter may be used to remove emboli such as thrombi formed in blood vessels. As shown in Patent Document 1, a suction catheter is a long medical device that is inserted percutaneously into a blood vessel, and can suck emboli collected by a filter of a filter device protruding from a tip opening through a lumen, and discharge them to the outside from a hub at the proximal end through the lumen.

[0003] Japanese Patent No. 5032489

[0004] When the shaft of the filter device is inserted into the lumen of the suction catheter, the radial movement of the suction catheter is restricted by the shaft of the filter device. Therefore, it is difficult to move the tip opening of the suction catheter to a position radially away from the shaft of the filter device. If it takes time to suck the emboli, a delay in the procedure will occur. Also, if it is difficult to suck the emboli, there is a possibility that the remaining emboli in the body will scatter.

[0005] By increasing the inner and outer diameters of the tip opening of the suction catheter, delays in the procedure and scattering of emboli can be suppressed. However, if the outer diameter of the tip opening is too large, it will be difficult to insert the suction catheter into a peripheral blood vessel.

[0006] The present invention has been made to solve the above-described problems, and an object thereof is to provide a suction catheter and a suction system that can be inserted into a narrow biological lumen and can effectively suck a wide range.

[0007] The above objective is achieved by the invention described in (1) below. (1) The suction catheter according to the present invention comprises a deformable tubular tip having a tip opening at its end, and a base shaft disposed on the proximal end side of the tip tip and having a proximal opening at its proximal end, and a main tube having a lumen that communicates from the tip opening to the proximal opening, wherein the cross-sectional shape of the inner surface of the tip opening perpendicular to the axis of the main tube has lengths in a first direction and a second direction perpendicular to the first direction, the second length in the second direction is longer than the first length in the first direction, and the cross-sectional shape of the inner surface of the base shaft perpendicular to the axis of the main tube is circular, and the tip opening is deformable when a dilator having an outer diameter less than or equal to the inner diameter of the base shaft is inserted into the lumen, the dilator being longer than the first length, shorter than the second length, and having an outer diameter less than or equal to the inner diameter of the base shaft.

[0008] The suction catheter described in (1) above can be inserted into narrow biological lumens because, when a dilator is inserted, the tip opening deforms so that the first length becomes longer and the second length becomes shorter, and the maximum outer diameter of the tip opening decreases. Furthermore, because the second length of the cross-sectional shape of the tip opening when the dilator is withdrawn is longer than the first length, the tip opening can reach a position radially away from the filter shaft even when the filter shaft of the filter device is inserted into the lumen, allowing for effective suction over a wide area.

[0009] (2) In the suction catheter described in (1) above, the cross-sectional shape of the tip opening may be elliptical or oblong. This allows the suction catheter to effectively change the maximum inner diameter of the inner surface of the tip opening, with the direction of the major axis of the ellipse or oblong being the second direction and the direction of the minor axis being the first direction. Furthermore, because the cross-sectional shape of the tip opening is easily deformed into a circular shape, it is easy to reduce the maximum outer diameter of the tip opening into which the dilator is inserted.

[0010] (3) In the suction catheter described in (1) or (2) above, the tip may be softer than the base shaft. This allows the tip to be easily deformed when a dilator is inserted. It also helps to suppress damage to biological tissue caused by contact with the tip.

[0011] (4) In the suction catheter described in (1) or (2) above, the tip may be harder than the base shaft. This allows the tip to easily break up the embolus and effectively aspirate the embolus from the tip opening.

[0012] (5) The suction catheter described in any one of (1) to (4) above may be used for aspirating emboli in pulmonary vessels. This allows the suction catheter to be inserted into narrow pulmonary vessels and to effectively aspirate a wide area of ​​the pulmonary vessels.

[0013] (6) The suction catheter described in any one of (1) to (4) above may be used for aspirating emboli in deep veins. This allows the suction catheter to be inserted into narrow deep veins and to effectively aspirate a wide area of ​​the deep veins.

[0014] (7) The suction catheter described in any one of (1) to (4) above may be used for aspirating emboli in peripheral blood vessels. This allows the suction catheter to be inserted into narrow peripheral blood vessels and to effectively aspirate a wide area of ​​peripheral blood vessels.

[0015] (8) The suction system according to the present invention is characterized by comprising a suction catheter as described in any one of (1) to (7) above, and a filter device comprising a long filter shaft that can be inserted into the lumen and a filter connected to the filter shaft for collecting emboli. As a result, when a dilator is inserted, the tip opening of the catheter of the suction system deforms so that the first length becomes shorter and the second length becomes longer, and the maximum outer diameter of the tip opening decreases, so that it can be inserted into a narrow biological lumen. Furthermore, since the second length of the cross-sectional shape of the tip opening of the suction catheter of the suction system when the dilator is withdrawn is longer than the first length, the tip opening can reach a position radially away from the filter shaft even when the filter shaft is inserted into the lumen, so that a wide area can be effectively aspirated. For this reason, the suction system can be inserted into a narrow biological lumen and can effectively aspirate emboli collected in the filter.

[0016] This is a plan view showing a suction system including a suction catheter according to an embodiment. This is a plan view showing the tip of the suction catheter, where (A) is an enlarged plan view of the tip of the suction catheter in Figure 1, and (B) is an enlarged plan view seen from arrow A in Figure 2(A). This is a cross-sectional view of the tip of the suction catheter, where (A) is a cross-sectional view along the line B-B in Figure 2(A), and (B) is a cross-sectional view along the line C-C in Figure 2(A). This is a plan view showing the tip of a suction catheter with a dilator inserted. This is a cross-sectional view of the tip of a suction catheter with a dilator inserted, where (A) is a cross-sectional view along the line D-D in Figure 4, and (B) is a cross-sectional view along the line E-E in Figure 4. This is a schematic diagram showing a filter device and suction catheter inserted into a blood vessel. This is a cross-sectional view showing a filter device and suction catheter inserted into a blood vessel, where (A) is a cross-sectional view along the line F-F in Figure 6, and (B) is a cross-sectional view of the suction catheter in Figure 7(A) rotated 90 degrees. These are cross-sectional views of the tip of a modified suction catheter, with (A) showing the cross-section of the first modified version, (B) showing the second modified version, and (C) showing the third modified version.

[0017] Embodiments of the present invention will be described below with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for illustrative purposes and may differ from the actual ratios. In the following description, the side of the suction catheter that is operated will be referred to as the "proximal end," and the side that is inserted into the body will be referred to as the "proximal end."

[0018] As shown in Figure 6, the suction catheter 10 according to an embodiment of the present invention is a long medical device that is inserted percutaneously into a blood vessel 100 and used to aspirate and remove an embolus 101, which is a substance that causes occlusion of the blood vessel 100. The embolus 101 is a substance that causes occlusion of the blood vessel 100, and is not limited to, but can be any substance that can cause occlusion of the blood vessel 100, such as a thrombus, plaque, calcified lesion, fat, tumor, biological tissue, or air.

[0019] The suction catheter 10 is used, for example, to treat pulmonary embolism, deep vein thrombosis, or peripheral vascular occlusion, but may also be used to treat other medical conditions. In the treatment of pulmonary embolism, the suction catheter 10 is used to treat embolisms in the pulmonary artery. In deep vein thrombosis, the suction catheter 10 is used to treat embolisms in veins running deeper than the deep fascia. In peripheral vascular occlusion, the suction catheter 10 is used to treat embolisms in arteries or veins in the leg or arm.

[0020] As shown in Figure 1, the suction catheter 10 is used together with a dilator 60 that can be inserted into the suction catheter 10 and a filter device 70 having a filter 71 for collecting the embolus 101. The suction catheter 10, dilator 60, and filter device 70 form a suction system 1.

[0021] As shown in Figures 1 to 3, the suction catheter 10 includes a tubular main tube 20 through which a lumen 21 is formed along the axial direction X, through which a wire (e.g., a guidewire) or embolizer 101 can pass; a hub 40 fixed to the proximal end of the main tube 20; and a kink-resistant protector 50. The outer and inner circumferential surfaces of at least the tip of the main tube 20 may be coated with a lubricating coating. The lubricating coating may be, for example, a hydrophilic polymer or a fluororesin material.

[0022] The hub 40 has a hub opening 41 that opens at the base end face of the hub 40 and communicates with the lumen 21 of the main tube 20, and a suction port 42 that opens on the side of the hub 40 and communicates with the lumen 21 of the main tube 20. By connecting a syringe or the like to the suction port 42, a suction force can be applied to the lumen 21 of the main tube 20. A valve body may be placed in the hub opening 41. The hub 40 does not have to have a suction port 42. In this case, the hub opening 41 functions as a suction port.

[0023] The main tube 20 has a base shaft 22 that is elongated in the axial direction X, and a tubular tip 23 fixed to the tip side of the base shaft 22.

[0024] The base shaft 22 is a long tube in the axial direction X, with a tip 23 connected to its front end and a hub 40 connected to its base end. A base end opening 24 is formed at the base end of the base shaft 22, through which the lumen 21 opens. The base end opening 24 communicates with the hub opening 41.

[0025] As shown in Figure 3(A), the base shaft 22 has an inner layer 25, a reinforcing body 26 located radially outside the inner layer 25, and an outer layer 27 covering the radially outside of the inner layer 25 and the reinforcing body 26. Radially outside means in a direction perpendicular to the axis of the main tube 20, and away from the axis. Radially inside means in a direction perpendicular to the axis of the main tube 20, and approaching the axis. The base shaft 22 does not have a portion with a curved axis at its tip, but it may have one. A suction catheter 10 having a portion with a curved axis allows the direction of the tip to be adjusted by rotation, so the direction of suction can be selected. The suction catheter 10 has a reinforcing body 26 on the base shaft 22 and has high torque transmission, so the direction of suction can be easily selected and deformation that causes the lumen 21 to collapse due to suction can be suppressed. The base shaft 22 may have other layers, may not have a reinforcing body 26, and may be formed of only one layer.

[0026] The inner layer 25 is a layered member that forms the lumen 21 of the main tube 20. The inner layer 25 has an inner diameter that is approximately constant in the axial direction X.

[0027] The reinforcing body 26 is a member for reinforcing the main tube 20 and has a plurality of wires 28 braided into a tubular shape. The reinforcing body 26 may be a coil formed by winding one or more wires 28 in a spiral shape, or a multi-strand coil formed by winding two or more wires 28 arranged in the circumferential direction into a coil shape. The wires 28 are loosely wound with gaps in the axial direction X of the main tube 20. The gaps in the wires 28 in the reinforcing body 26 are filled with the material of the outer layer 27 or the inner layer 25. The wires 28 are made of a metal such as stainless steel or NiTi. The cross-sectional shape of the wires 28 is not particularly limited and may be rectangular, square, circular, oval, or elliptical, for example. The wires 28 may also be bundles of two or more strands. The main tube 20 having the reinforcing body 26 can secure sufficient rigidity and strength without increasing the wall thickness, that is, while keeping the inner diameter of the main tube 20 relatively large.

[0028] The outer layer 27 is a member that covers the radially outer side of the inner layer 25 and the reinforcing body 26. The outer layer 27 has an outer diameter that is approximately constant in the axial direction X.

[0029] The inner layer 25 and the outer layer 27 may be formed from the same material or from different materials. Examples of constituent materials for the inner layer 25 and the outer layer 27 include polystyrene, polyolefin, polyurethane, polyester, polyamide, and various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based materials. One or more of these can be combined (polymer alloy, polymer blend, laminate, etc.), and thermoplastic elastomers are preferred.

[0030] The outer diameter D2 of the base shaft 22 is preferably 3.0 mm or more and 9.0 mm or less, and more preferably 3.5 mm or more and 5.5 mm or less. The inner diameter D1 of the base shaft 22 is preferably 2.5 mm or more and 8.5 mm or less, and more preferably 3.0 mm or more and 5.5 mm or less. The outer diameter D2 and inner diameter D1 of the base shaft 22 are constant along the axial direction X, but may vary slightly, for example, decreasing at the tip near the tip 23.

[0031] As shown in Figures 1 to 3, the tip 23 has a tip base portion 29 with a circular cross-sectional shape perpendicular to the axis of the main tube 20, a tip portion 30 with a non-circular cross-sectional shape perpendicular to the axis of the main tube 20, and a transition portion 31 between the tip base portion 29 and the tip portion 30 where the inner and outer diameters gradually change.

[0032] The tip base end 29 has a shape that is continuous with the base shaft 22. Therefore, the inner diameter of the tip base end 29 matches the inner diameter D1 of the base shaft 22, and the outer diameter of the tip base end 29 matches the outer diameter D2 of the base shaft 22. However, the inner and outer diameters of the tip base end 29 do not necessarily have to match the inner diameter D1 and outer diameter D2 of the base shaft 22.

[0033] The tip portion 30 has a tip opening 32 through which the lumen 21 opens. The cross-sectional shape of the inner circumferential surface of the tip opening 32, which is perpendicular to the axis of the main tube 20, has lengths in a first direction Y parallel to the cross-section and a second direction Z perpendicular to the first direction Y, with the second length L2 in the second direction Z being longer than the first length L1 in the first direction Y. In this embodiment, the cross-sectional shape of the inner circumferential surface of the tip opening 32 is elliptical. The cross-sectional shape of the inner circumferential surface of the tip portion 30 is constant from the tip of the tip tip 23 toward the base end. Note that the tip portion 30 may be formed only at the tip of the tip tip 23. That is, the length L4 in the axial direction X of the tip portion 30 is 0 mm or more, and in this embodiment it is greater than 0 mm but may be 0 mm. The length L4 is preferably 2.0 mm or more and 7.0 mm or less, and more preferably 3.0 mm or more and 5.0 mm or less.

[0034] The first length L1 is shorter than the inner diameter D1 of the base shaft 22, and the second length L2 is longer than the inner diameter D1 of the base shaft 22. Furthermore, the first length L1 is shorter than the outer diameter D3 (see Figure 5) of the portion of the dilator 60 that is inserted into the lumen 21, and the second length L2 is longer than the outer diameter D3 of the portion of the dilator 60 that is inserted into the lumen 21. The circumference of the inner surface of the tip opening 32 is approximately the same as the circumference of the inner surface of the base shaft 22. The circumference of the inner surface of the tip opening 32 is approximately the same as the circumference of the dilator 60, or slightly longer than the circumference of the dilator 60.

[0035] The circumference of the inner surface of the tip opening 32 is preferably approximately equal to the circumference of the inner surface of the base shaft 22 (or tip base end 29). If the circumference of the inner surface of the tip opening 32 is longer than the circumference of the inner surface of the base shaft 22 (or tip base end 29), it may be difficult to house the tip 23 in the sheath. If the circumference of the inner surface of the tip opening 32 is shorter than the circumference of the inner surface of the base shaft 22 (or tip base end 29), the suction area of ​​the tip opening 32 will be reduced.

[0036] The circumference of the inner surface of the tip opening 32 may be slightly shorter or slightly longer than the circumference of the inner surface of the base shaft 22 (or tip base end 29). If the circumference of the inner surface of the tip opening 32 is slightly shorter than the circumference of the inner surface of the base shaft 22 (or tip base end 29), the tip 23 can easily enter narrow areas such as constrictions. If the circumference of the inner surface of the tip opening 32 is slightly longer than the circumference of the inner surface of the base shaft 22 (or tip base end 29), the suction area of ​​the tip opening 32 becomes larger.

[0037] As an example of the dimensions of the tip 23, the inner diameter D1 of the base shaft 22 is 4.5 mm, the outer diameter D2 is 5.2 mm, the first length L1 is 3.6 mm, the second length L2 is 5.5 mm, and the thickness of the tip 23 is 0.35 mm. The axial length L3 of the tip 23 in the X direction is 5.0 mm. The axial length L4 of the tip portion 30 in the X direction is 3.0 mm.

[0038] As another example, the inner diameter D1 of the base shaft 22 is 4.0 mm, the outer diameter D2 is 4.4 mm, the first length L1 is 3.5 mm, the second length L2 is 4.5 mm, and the thickness of the tip 23 is 0.2 mm. The axial length L3 of the tip 23 in the X direction is 7.0 mm. The axial length L4 of the tip portion 30 in the X direction is 5.0 mm.

[0039] The thickness of the tip portion 30 is approximately the same as the thickness of the base portion 29 of the tip, but may differ. For example, the thickness of the tip 23 may decrease towards the tip.

[0040] The shape of the transition portion 31 gradually changes from the tip base portion 29 to the tip portion 30. That is, the inner diameter of the transition portion 31 in the first direction Y gradually decreases from D1 at the base to L1 towards the tip. The inner diameter of the transition portion 31 in the second direction Z gradually increases from D1 at the base to L2 towards the tip. The circumferential length of the inner surface of the transition portion 31 is preferably approximately constant along the axial direction X, but it does not have to be constant.

[0041] The base end of the tip 23 is preferably located closer to the tip than the front end of the reinforcing body 26. This prevents the deformation of the tip 23 from being hindered by the reinforcing body 26. The tip 23 is made of a resin that is softer than the resin that forms the base shaft 22, i.e., the resin that forms the inner layer 25 and the outer layer 27. Alternatively, the tip 23 may be made of a resin that is harder than the resin that forms the base shaft 22, or it may be made of a resin with the same hardness as the resin that forms the base shaft 22. The hardness of the resin can be compared using Shore D hardness, Shore A hardness, Rockwell hardness, etc.

[0042] The tip 23 is preferably made of an elastically deformable material that can be deformed to have an inner diameter approximately circular and then restored to its original shape. Examples of materials for the tip 23 include polystyrene, polyolefin, polyurethane, polyester, polyamide, and various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based materials. One or more of these can be combined (polymer alloy, polymer blend, laminate, etc.).

[0043] As shown in Figure 1, the dilator 60 has a tubular dilator shaft 62 through which a dilator lumen 61, through which a wire (e.g., a guide wire) can pass, is formed along its axis, and a dilator hub 63 fixed to the proximal end of the dilator shaft 62. The dilator hub 63 has a dilator hub opening 64 that opens at the proximal end face of the dilator hub 63 and communicates with the dilator lumen 61. The dilator hub 63 may or may not be connectable to the hub 40 of the suction catheter 10.

[0044] The filter device 70 has a net-like filter 71 that collects emboli 101 and a long filter shaft 72 connected to the filter 71. The filter 71 is not particularly limited as long as it can collect emboli 101. For example, it has a plurality of wires 73 knitted in a cylindrical shape so as to have gaps, and the plurality of wires 73 are gathered and fixed at the tip fixing portions 74 and the base end fixing portions 75 at both ends. The cylindrical portion between the tip fixing portion 74 and the base end fixing portion 75 of the filter 71 can be elastically expanded and contracted in diameter. It is preferable that the maximum outer diameter of the filter 71 is larger than the maximum outer diameter of the tip chip 23 of the aspiration catheter 10. The filter 71 is accommodated in a catheter or a sheath in a diameter-reduced state and transported to the target position in the blood vessel 100, and is released from the inside of the catheter or the sheath, so that it expands in diameter by its own elastic force and is placed on the inner wall surface of the blood vessel 100. Since the filter 71 is net-like, it can collect emboli 101 flowing in the blood vessel 100. Note that the shape of the filter 71 is not particularly limited. For example, the filter 71 may be umbrella-shaped, disk-shaped, cage-shaped, or the like. Alternatively, the filter 71 may be formed not by a plurality of wires 73 but by a sheet-like member having a plurality of through holes.

[0045] Next, a method of using the aspiration catheter 10 according to the present embodiment will be described.

[0046] As shown in FIGS. 4 to 5, the operator inserts the aspiration catheter 10 containing the dilator 60 into the lumen 21 and advances it along a guide wire (not shown) inserted into the dilator lumen 61 to reach the target position in the blood vessel 100. The distal end portion of the dilator 60 is also disposed inside the distal tip 23 of the lumen 21. As shown in FIGS. 2 to 3, the first length L1 of the distal tip 23 before the dilator 60 is inserted is shorter than the outer diameter D2 of the dilator 60, and the second length L2 of the distal tip 23 is longer than the outer diameter D2 of the dilator 60. Therefore, as shown in FIGS. 4 to 5, when the dilator 60 is inserted into the lumen 21, the distal tip 23 is deformed so as to follow the shape of the dilator 60. That is, the cross-sectional shape of the distal tip 23 becomes a shape close to a perfect circle. For this reason, the maximum outer diameter of the distal tip 23 becomes smaller, and the operability of the aspiration catheter 10 inside a narrow blood vessel 100, a sheath, or another catheter is improved.

[0047] When the distal end of the aspiration catheter 10 reaches the target position, the operator removes the dilator 60 while leaving the aspiration catheter 10. As a result, the distal tip 23 deformed by the dilator 60 restores to its original shape having the first length L1 and the second length L2 in cross section by its own elastic force. The maximum outer diameter of the distal tip 23 is preferably smaller than the maximum outer diameter of the filter 71 and smaller than the inner diameter of the blood vessel 100 where the filter 71 is to be placed. Thereby, it is possible to prevent the distal tip 23 from getting caught on the blood vessel 100.

[0048] Next, the operator inserts the filter device 70 into the lumen 21 from the proximal end side of the aspiration catheter 10, projects the filter 71 to the outside from the distal opening 32 to expand its diameter, and places it on the inner wall surface of the blood vessel 100 as shown in FIG. 6. The filter 71 placed on the inner wall surface of the blood vessel 100 can collect emboli 101 flowing with the blood.

[0049] Note that the filter device 70 may be placed in the blood vessel 100 before inserting the aspiration catheter 10 into the blood vessel 100. Also, the filter device 70 may be housed in a catheter or a sheath other than the aspiration catheter 10 and transported to the target position for placement.

[0050] The operator connects a device that applies suction force, such as a syringe, to the suction port 42 of the suction catheter 10, and while applying suction force to the lumen 21, brings the tip opening 32 of the suction catheter 10 closer to the filter 71. This allows the operator to aspirate the embolus 101 collected in the filter 71 into the lumen 21 through the tip opening 32. The embolus 101 aspirated into the lumen 21 is collected by the device connected to the suction port 42. At this time, the cross-sectional shape of the inner surface of the tip opening 32 of the tip tip 23, shown by the solid line in Figure 7(A), is non-circular, having a second length L2 that is longer in the second direction Z. Therefore, the maximum clearance between the inner surface of the tip opening 32 and the outer surface of the filter shaft 72 that penetrates the lumen 21 is longer than when the cross-sectional shape of the inner surface of the tip opening 32 is perfectly circular. For this reason, the tip opening 32 of the tip tip 23 can aspirate large embolus 101. Generally, once the embolus 101 clogs the lumen 21, it is necessary to remove the suction catheter 10 and clean it in order to restore the suction force. In contrast, the suction catheter 10 according to this embodiment is less prone to the embolus 101 clogging the lumen 21, thus reducing the need to remove the suction catheter 10 and clean it in order to restore the suction force.

[0051] Furthermore, as shown in Figures 7(A) and (B), the operator can use the device by rotating the tip opening 32 of the tip tip 23 around the axis of the main tube 20, thereby enabling suction over a wide area around the entire circumference.

[0052] Furthermore, because the tip 23 is elongated in the second direction Z, it can move far radially relative to the filter shaft 72, as shown by the dashed line in Figures 7(A) and (B). Therefore, the operator can suction a wider area by rotating the tip 23 while moving it far radially relative to the filter shaft 72.

[0053] After the embolus 101 has been aspirated using the suction catheter 10, the operator places the filter 71 into the suction catheter 10 and removes the filter device 70 and the suction catheter 10 from the blood vessel 100. The filter device 70 may be removed in a different catheter or sheath than the suction catheter 10. It is preferable to remove the suction catheter 10 by inserting the dilator 60 into the lumen 21 from the proximal end of the suction catheter 10 and deforming the cross-section of the tip 23 into a shape close to a perfect circle. This reduces the maximum outer diameter of the tip 23 of the suction catheter 10, making it easier to remove the suction catheter 10 from the narrow blood vessel 100.

[0054] As described above, the suction catheter 10 according to this embodiment comprises a deformable tubular tip 23 having a tip opening 32 at its tip, and a base shaft 22 positioned on the base end side of the tip tip 23 and having a base opening 24 at its base end, and a main tube 20 having a lumen 21 that communicates from the tip opening 32 to the base opening 24, wherein the cross-sectional shape of the inner surface of the tip opening 32 perpendicular to the axis of the main tube 20 has lengths in a first direction Y and a second direction Z perpendicular to the first direction Y, and the second length L2 in the second direction Z is longer than the first length L1 in the first direction Y, and the cross-sectional shape of the inner surface of the base shaft 22 perpendicular to the axis of the main tube 20 is circular, and the dilator 60 having an outer diameter less than or equal to the inner diameter of the base shaft 22 is inserted into the lumen 21, thereby making the tip opening 32 deformable. As a result, when the dilator 60 is inserted, the tip opening 32 of the suction catheter 10 deforms so that the first length L1 becomes longer and the second length L2 becomes shorter, reducing the maximum outer diameter of the tip opening 32, which allows it to be inserted into a narrow biological lumen. Furthermore, when the dilator 60 is withdrawn, the second length L2 of the cross-sectional shape of the tip opening 32 of the suction catheter 10 is longer than the first length L1, so even when the filter shaft 72 of the filter device 70 is inserted into the lumen 21, the tip opening 32 can reach a position radially away from the filter shaft 72, allowing for effective suction over a wide area.

[0055] Furthermore, the cross-sectional shape of the tip opening 32 is elliptical or oblong. This allows the suction catheter 10 to effectively change the maximum inner diameter of the inner surface of the tip opening 32, with the direction of the major axis of the ellipse or oblong being the second direction Z and the direction of the minor axis being the first direction Y. In addition, because the cross-sectional shape of the tip opening 32 can be easily deformed into a circular shape, it is easy to reduce the maximum outer diameter of the tip opening 32 into which the dilator 60 is inserted.

[0056] Furthermore, the tip 23 may be softer than the base shaft 22. This allows the tip 23 to be easily deformed when the dilator 60 is inserted. It also helps to suppress damage to biological tissue caused by contact with the tip 23.

[0057] Furthermore, the tip 23 may be harder than the base shaft 22. This allows the tip 23 to easily break up the embolus 101, and the embolus 101 to be effectively aspirated from the tip opening 32.

[0058] Furthermore, the suction catheter 10 may be used to aspirate emboli 101 in the pulmonary blood vessels. This allows the suction catheter 10 to be inserted into narrow pulmonary blood vessels and to effectively aspirate a wide area of ​​the pulmonary blood vessels.

[0059] Furthermore, the suction catheter 10 may be used to aspirate an embolus 101 in a deep vein. This allows the suction catheter 10 to be inserted into a narrow deep vein and to effectively aspirate a wide area of ​​the deep vein.

[0060] Furthermore, the suction catheter 10 may be used to aspirate emboli 101 in peripheral blood vessels. This allows the suction catheter 10 to be inserted into narrow peripheral blood vessels and to effectively aspirate a wide area of ​​peripheral blood vessels.

[0061] Furthermore, the suction system 1 in this embodiment includes the suction catheter 10 described above, and a filter device 70 equipped with a long filter shaft 72 that can be inserted into the lumen 21 and a filter 71 connected to the filter shaft 72 for collecting embolus 101. As a result, when the dilator 60 is inserted, the tip opening 32 of the suction catheter 10 of the suction system 1 deforms so that the first length L1 becomes shorter and the second length L2 becomes longer, and the maximum outer diameter of the tip opening 32 decreases, making it possible to insert it into a narrow biological lumen. In addition, when the dilator 60 is withdrawn, the second length L2 of the cross-sectional shape of the tip opening 32 of the suction catheter 10 of the suction system 1 is longer than the first length L1, so even when the filter shaft 72 is inserted into the lumen 21, the tip opening 32 can reach a position radially away from the filter shaft 72, and a wide area can be effectively aspirated. For this reason, the suction system 1 can be inserted into a narrow biological lumen and can effectively aspirate embolus 101 collected in the filter 71.

[0062] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made by those skilled in the art within the technical framework of the present invention. For example, the cross-sectional shape of the inner circumferential surface of the tip opening 32 formed in the tip portion 30 is not limited to an ellipse, as long as the second length L2 is longer than the first length L1 and is not circular. For example, as shown in the first modified example in Figure 8(A), the cross-sectional shape of the inner circumferential surface of the tip opening 32 may be an oval shape other than an ellipse.

[0063] Furthermore, as shown in the second modified example in Figure 8(B), the cross-sectional shape of the inner circumferential surface of the tip opening 32 may be oval. In this case, the tip portion 30 has a top portion 33 with a narrow width in the first direction Y on one side in the second direction Z, and a bottom portion 34 with a wide width in the first direction Y on the other side in the second direction Z. The radius of curvature of the top portion 33 is smaller than the radius of curvature of the bottom portion 34. In this case, for example, by arranging the filter shaft 72 in the tip opening 32 on the top portion 33 side, the bottom portion 34 side of the tip opening 32, which has a larger area, can be positioned away from the filter shaft 72 to avoid interference, thereby improving suction efficiency. Then, for example, with the filter shaft 72 positioned in the tip opening 32 on the top portion 33 side, by rotating the bottom portion 34 side, which has a larger area, around the top portion 33 side of the tip opening 32, a wide area can be efficiently suctioned.

[0064] Furthermore, as shown in the third modified example in Figure 8(C), the cross-sectional shape of the inner circumferential surface of the tip opening 32 may be pear-shaped. In this case, similar to the second modified example, the tip portion 30 has a top portion 33 with a narrow width in the first direction Y on one side in the second direction Z, and a bottom portion 34 with a wide width in the first direction Y on the other side in the second direction Z. The radius of curvature of the top portion 33 is smaller than the radius of curvature of the bottom portion 34. Two inwardly convex portions 35 are formed between the top portion 33 and the bottom portion 34. In the case of the third modified example, for example, by arranging the filter shaft 72 in the tip opening 32 on the top portion 33 side, the bottom portion 34 side of the tip opening 32, which has a wider area, can be positioned away from the filter shaft 72 to avoid interference, thereby improving suction efficiency. The inward convex portions 35 can hold the position of the filter shaft 72 in a desired position. For example, by positioning the filter shaft 72 at the tip opening 32 on the top 33 side and rotating the tip opening 32 so that the wider bottom 34 side swings around the top 33 side, a wide area can be efficiently suctioned.

[0065] Furthermore, the biological lumen into which the suction catheter 10 is inserted is not limited to a blood vessel 100, but may also be a blood vessel, ureter, bile duct, fallopian tube, hepatic duct, etc.

[0066] This application is based on Japanese Patent Application No. 2024-226016, filed on December 23, 2024, and its disclosures are referenced and incorporated as a whole.

[0067] 1 Suction system 10 Suction catheter 20 Main tube 21 Lumen 22 Base shaft 23 Tip 24 Proximal opening 29 Tip proximal end 30 Tip tip 32 Tip opening 60 Dilator 61 Dilator lumen 62 Dilator shaft 70 Filter device 71 Filter 72 Filter shaft 100 Blood vessel (biological lumen) 101 Embolism L1 First length L2 Second length X Axial direction Y First direction Z Second direction

Claims

1. A suction catheter comprising a deformable tubular tip having a tip opening at its end, and a base shaft positioned on the proximal end side of the tip and having a proximal opening at its proximal end, wherein a lumen is formed that communicates from the tip opening to the proximal opening, wherein the cross-sectional shape of the inner surface of the tip opening perpendicular to the axis of the main tube has lengths in a first direction and a second direction perpendicular to the first direction, the second length in the second direction is longer than the first length in the first direction, the cross-sectional shape of at least a portion of the inner surface of the base shaft perpendicular to the axis of the main tube is circular, and the tip opening is deformable when a dilator having an outer diameter longer than the first length, shorter than the second length, and less than or equal to the inner diameter of the base shaft is inserted into the lumen.

2. The suction catheter according to claim 1, characterized in that the cross-sectional shape of the tip opening is elliptical or oblong.

3. The suction catheter according to claim 1 or 2, characterized in that the tip is softer than the base shaft.

4. The suction catheter according to claim 1 or 2, characterized in that the tip is harder than the base shaft.

5. The aspiration catheter according to claim 1 or 2, characterized in that it is used for aspirating emboli from pulmonary blood vessels.

6. The aspiration catheter according to claim 1 or 2, characterized in that it is used for aspirating emboli in deep veins.

7. The aspiration catheter according to claim 1 or 2, characterized in that it is used for aspirating emboli in peripheral blood vessels.

8. A suction system comprising the suction catheter described in claim 1, and a filter device comprising a long filter shaft insertable into the lumen and a filter connected to the filter shaft for collecting emboli.

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