Thrombus aspiration catheter

Abstract

Provided is a thrombus aspiration catheter having a novel structure in which the shape of the tip section can be designed with a large degree of freedom. A thrombus aspiration catheter (10) is provided with: an aspiration tube (12) having an aspiration tube lumen (18) for aspirating thrombus in a blood vessel; a guidewire insertion tube (14) having a guidewire lumen (24) through which a guidewire (56) is inserted; and a tip tip (16) which is attached to the tip section of the suction tube (12) and the guidewire insertion tube (14) and which has a tip lumen (34) that communicates with the suction tube lumen of the suction tube (12), a tube fitting groove (38) that extends in the axial direction is provided on the outer peripheral surface of the tip tip (16), and the guidewire insertion tube (14), which is separate from the tip tip (16), is inserted into the tube fitting groove (38) and affixed to the tip tip (16).

Description

Technical Field

[0001] The present invention relates to a thrombus aspiration catheter for aspirating and removing thrombus in a blood vessel. Background Art

[0002] Peripheral arterial disease (PAD), which develops due to insufficient blood flow, is known to cause intermittent claudication, ulcers, necrosis, and other potential problems as it progresses, and therefore sometimes requires treatment. For example, in cases of PAD caused by deteriorating blood flow due to arteriosclerosis, thrombus removal therapy has been proposed to eliminate thrombotic lesions by removing thrombus within the blood vessels. One method of removing thrombus within the blood vessels is to aspirate and remove the thrombus using a thrombus aspiration catheter.

[0003] A thrombus aspiration catheter, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2013-126573 (Patent Document 1), includes an aspiration lumen for aspirating thrombi, is percutaneously inserted into a blood vessel, and aspirates blood containing thrombi into the aspiration lumen, thereby removing the thrombi from the blood vessel.

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-126573 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Furthermore, the thrombus aspiration catheter of Patent Document 1 is formed with a beveled distal end, with the distal end opening of the aspiration lumen opening obliquely forward (toward the distal end). By forming the distal end opening of the aspiration lumen in this oblique shape, it is expected that the opening area can be ensured and the direction of the aspiration force can be adjusted.

[0008] However, the structure of Patent Document 1 is limited to the beveled shape of the distal end of the thrombus aspiration catheter. This significantly limits the design freedom of the catheter distal end, which significantly influences the direction of the aspiration force and insertability into the blood vessel. In particular, simply orienting the aspiration lumen obliquely forward will aspirate thrombi in the anterior direction, but may make it difficult to effectively aspirate thrombi adhering to the lateral side of the blood vessel wall, preventing efficient aspiration and removal of thrombi.

[0009] The problem to be solved by the present invention is to provide a thrombus aspiration catheter having a novel structure in which the shape of the distal end can be designed with a large degree of freedom.

[0010] Means used to solve problems

[0011] The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is merely illustrative and can be appropriately combined and employed with one another. Furthermore, the multiple components described in each embodiment can be individually identified and employed as much as possible, and can be appropriately combined and employed with any component described in another embodiment. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

[0012] The present inventors believed that by forming the distal end of a thrombus aspiration catheter with a distal tip that is independent of the tube portion, the catheter's distal end could achieve greater freedom in shape. However, through trial production and research, the present inventors discovered that, while the catheter's distal end has greater freedom in shape when formed as a molded part, such as an injection molded part, it is difficult to form the small-diameter lumen through which a guidewire is inserted, a significant factor limiting the shape of the distal tip. Based on this newly acquired knowledge, the present inventors completed the present invention.

[0013] The first method is a thrombus aspiration catheter, which includes: a suction tube, which has a suction lumen for aspirating thrombus in a blood vessel; a guidewire insertion tube, which has a guidewire lumen for inserting a guidewire; and a front end tip, which is installed at the front end portion of the suction tube and the guidewire insertion tube, and has a front end lumen connected to the suction lumen of the suction tube. A tube assembly groove extending in the axial direction is provided on the outer peripheral surface of the front end tip, and the guidewire insertion tube independent of the front end tip is inserted into the tube assembly groove and fixedly connected to the front end tip.

[0014] According to the thrombus aspiration catheter structured in accordance with this method, the catheter front end comprises a tip that is independent of the aspiration tube and the guidewire insertion tube. Therefore, by forming the tip into a molded product such as an injection molded product, the catheter front end can be greatly shaped with greater freedom. Furthermore, since the tip is separate from the guidewire insertion tube, the shape and structure of the tip can be designed with greater freedom, regardless of the formability of the small-diameter guidewire lumen. This large degree of freedom in the design of the tip allows, for example, the opening on the front side of the lumen connected to the aspiration lumen to be formed to open laterally to the tip, and the direction of the suction force can be set with greater freedom.

[0015] A second embodiment is that, in the thrombus aspiration catheter described in the first embodiment, the front end lumen has a suction opening portion that opens laterally on the outer peripheral surface of the front end tip, and a closing wall surface that closes the front end side of the front end lumen is provided on the front end side of the suction opening portion in the front end tip, and the tube mounting groove is arranged at a position deviated from the suction opening portion in the circumferential direction of the front end tip.

[0016] In a thrombus aspiration catheter configured according to this embodiment, the aspiration opening of the distal lumen opens laterally of the distal tip rather than toward the distal end of the distal tip. This allows the aspiration force to be efficiently applied laterally of the distal tip, effectively removing a thrombus adhered to the inner surface of a blood vessel wall, for example.

[0017] The suction opening is opened at a position offset from the tube mounting groove in the circumferential direction. Therefore, the suction opening is not covered by the guide wire insertion tube attached to the front end tip, the opening area can be efficiently ensured, and the suction opening can be easily brought close to the blood vessel wall.

[0018] A third embodiment is a thrombus aspiration catheter according to the second embodiment, wherein the distal end portion of the distal tip is formed as a small-diameter portion including a tapered conical portion, and the proximal end portion of the distal tip is formed as a cylindrical large-diameter portion having a larger diameter than the small-diameter portion, and the aspiration opening is opened in the large-diameter portion.

[0019] The thrombus aspiration catheter constructed according to this embodiment has a small-diameter distal tip, which improves insertability into blood vessels and facilitates access to narrowed blood vessels. Furthermore, the large-diameter proximal tip ensures a large cross-sectional area of ​​the aspiration lumen and opening, enabling efficient thrombus recovery.

[0020] A fourth embodiment is a thrombus aspiration catheter according to the second or third embodiment, wherein the distal tip is formed of a resin material mixed with an X-ray opaque material, and an X-ray transparent hole penetrating the bottom wall of the tube mounting groove is formed in the distal tip at a position that overlaps with the aspiration opening in a radial direction of the distal tip.

[0021] According to the thrombus aspiration catheter structured in accordance with this embodiment, visibility under X-ray fluoroscopy can be ensured by the distal tip. In particular, by employing a distal tip formed by mixing an X-ray opaque material with a resin material, visibility can be ensured at a lower cost than by providing a ring-shaped marker made of a precious metal.

[0022] Furthermore, when visually observing the distal tip in the direction of the suction opening under X-ray fluoroscopy, the X-ray transmittance is higher in the area where the X-ray transmission hole and the suction opening overlap, resulting in a thinner contrast image in the area where the X-ray transmission hole and the suction opening overlap. Therefore, even under low-resolution X-ray fluoroscopy, the opening direction of the suction opening can be easily determined based on the contrast density.

[0023] A fifth embodiment is the thrombus aspiration catheter according to any one of the second to fourth embodiments, wherein the inclination angle of the distal end side wall surface of the aspiration opening relative to the axial direction of the distal tip is greater than the inclination angle of the proximal end side wall surface of the aspiration opening relative to the axial direction of the distal tip.

[0024] According to the thrombus aspiration catheter structured according to this embodiment, the distal end wall surface of the aspiration opening is formed at a large inclination angle. This allows, for example, efficient scraping of thrombi adhered to the inner wall of a blood vessel using the distal end wall surface of the aspiration opening, thereby improving thrombus recovery performance. Furthermore, the proximal end wall surface of the aspiration opening is formed at a small inclination angle. This reduces the proximal end wall surface of the aspiration opening from catching on the blood vessel wall when the thrombus aspiration catheter is inserted into a blood vessel and advanced distally, thereby enabling smooth insertion.

[0025] A sixth aspect is the thrombus aspiration catheter according to any one of the first to fifth aspects, further comprising a control mechanism for applying an external operating force to bend and deform the distal ends of the aspiration tube and the guidewire insertion tube.

[0026] According to the thrombus aspiration catheter configured according to this embodiment, the distal end of the aspiration tube is bent and deformed by the control mechanism, thereby bringing the aspiration port of the thrombus connected to the aspiration lumen closer to the thrombus, thereby enabling efficient aspiration and removal of the thrombus.

[0027] Effects of the Invention

[0028] According to the present invention, the shape of the distal end of the thrombus aspiration catheter can be designed with a large degree of freedom. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a right side view showing the thrombus aspiration catheter as the first embodiment of the present invention.

[0030] Figure 2 yes Figure 1 A top view of the thrombus aspiration catheter is shown.

[0031] Figure 3 yes Figure 2 Sectional view III-III.

[0032] Figure 4 yes Figure 3 IV-IV sectional view of FIG.

[0033] Figure 5 yes Figure 3 VV cross-sectional view.

[0034] Figure 6 yes Figure 3 VI-VI sectional view.

[0035] Figure 7 yes Figure 3 VII-VII sectional view.

[0036] Figure 8 yes Figure 3 Sectional view VIII-VIII of FIG.

[0037] Figure 9 It is composed Figure 1 A perspective view of the front end tip of the thrombus aspiration catheter is shown.

[0038] Figure 10 From another angle Figure 9 A perspective view of the front end tip is shown.

[0039] Figure 11A It's shot from above Figure 1 Radiograph of the thrombus aspiration catheter shown.

[0040] Figure 11B Shot from the right Figure 1 Radiograph of the thrombus aspiration catheter shown.

[0041] Figure 12 This is a cross-sectional view showing a thrombus aspiration catheter according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0043] Figures 1 to 8 The thrombus aspiration catheter 10 is shown as a first embodiment of the present invention. The thrombus aspiration catheter 10 is a catheter for thrombus aspiration therapy for removing thrombi from blood vessels by aspiration, and is particularly suitable for removing thrombi from blood vessels of the lower limbs. The thrombus aspiration catheter 10 has a structure in which a front end tip 16 is attached to the front end of the aspiration tube 12 and the guide wire insertion tube 14. In principle, the up and down directions refer to the Figure 1 In principle, the front-back direction refers to Figure 1 The left and right directions in Figure 2 The up and down directions in .

[0044] The suction tube 12 is a hollow body with a roughly circular cross-section, and its axially extending inner cavity forms the suction lumen 18. The suction tube 12 in this embodiment comprises a braided layer 20 formed by weaving together metal wires, such as stainless steel, and a two-layered peripheral wall with an inner layer 22 made of a low-friction material, such as fluororesin. The braided layer 20 provides the suction tube 12 with flexibility, ensuring axial pushability. Furthermore, the inner circumference of the braided layer 20 is covered by the low-friction inner layer 22, thereby reducing flow resistance within the suction lumen 18. The peripheral wall of the suction tube 12 can have a multilayer structure, for example, with three or more layers, or a single layer structure with only one layer. The braided layer 20 is not required; for example, the peripheral wall of the suction tube 12 can be formed into a multilayer structure using multiple resin materials of varying quality. Alternatively, a reinforcing layer made of spiral metal wires can be provided in place of or in addition to the braided layer 20.

[0045] The guidewire insertion tube 14 is a hollow body with a roughly circular cross-section, and an inner cavity that passes through in the axial direction forms a guidewire lumen 24. The guidewire insertion tube 14 is formed of a synthetic resin or the like and has flexibility. The inner diameter and outer diameter of the guidewire insertion tube 14 are formed to be smaller than the inner diameter and outer diameter of the suction tube 12. The guidewire insertion tube 14 does not have a braided body like the suction tube 12, and its flexibility is higher than that of the suction tube 12. The guidewire insertion tube 14 of this embodiment has a peripheral wall with a single-layer structure, but may also have a peripheral wall with a multi-layer structure, for example, composed of two or more resins. Preferably, the X-ray transmittance of the guidewire insertion tube 14 is higher than the transmittance of the front end tip 16, and is preferably formed of a material that does not contain X-ray opaque material.

[0046] The front end tip 16 has both flexibility to achieve the ability to follow the curvature of the blood vessel and deformation rigidity to prevent the front end lumen 34 from being flattened by the suction force (negative pressure) described later. The front end tip 16 is formed of, for example, an X-ray opaque resin obtained by mixing an X-ray opaque material such as bismuth oxide into a resin material such as polyethylene. Figure 9 、 Figure 10 As shown, the distal tip 16 integrally includes a small diameter portion 26 constituting the distal end portion and a large diameter portion 28 constituting the proximal end side of the small diameter portion 26. The distal tip 16, the suction tube 12, and the guidewire insertion tube 14 are formed as separate components.

[0047] The small diameter portion 26 is formed as a semi-cylindrical portion 30 extending in the axial direction with a substantially constant outer diameter at the front end, and is formed as a conical portion 32 whose base end portion decreases in diameter toward the front end. The conical portion 32 is composed of a curved surface with a smooth outer circumference, and is provided to be smoothly continuous with the semi-cylindrical portion 30. Figure 5 As shown, the small diameter portion 26 is preferably formed flat in the vertical direction at least in the conical portion 32 .

[0048] The large-diameter portion 28 is formed into a generally cylindrical shape with a larger diameter than the small-diameter portion 26. It includes a distal lumen 34 extending axially and opening toward the proximal end. In this embodiment, a thin-walled connecting portion 36 with a stepped outer diameter is provided at the proximal end of the large-diameter portion 28. Furthermore, when the distal tip 16 is obtained by die molding, for example, it is preferable to provide a draft angle in the large-diameter portion 28 to facilitate removal from the mold when the molded product is axially demolded. In this embodiment, the large-diameter portion 28 is formed so that its diameter increases slightly from the distal end toward the proximal end.

[0049] The maximum outer diameter R of the front end tip 16 (see Figure 2 ) is set to 1.5 mm ≤ R ≤ 3.0 mm. Thus, the thrombus aspiration catheter 10 having the distal tip 16 can be preferably used for thrombus aspiration therapy on blood vessels in the lower limbs, for example. Examples of blood vessels in the lower limbs include the iliac artery and vein, the femoral artery and vein, and the popliteal (infrapopliteal) artery and vein.

[0050] like Figure 10 As shown, the distal tip 16 is provided with a tube mounting groove 38 extending axially and opening onto the lower surface. Tube mounting groove 38 extends along the entire axial length of the distal tip 16, with a substantially uniform cross-sectional shape, and opens at the distal end and base end surfaces of the distal tip 16. Tube mounting groove 38 has an inner surface with an arcuate cross-section, with the width increasing downward. Furthermore, tube mounting groove 38 can be formed with a major arc cross-section extending over more than half its circumference. This allows the opening width of tube mounting groove 38 to be smaller than the diameter of the guidewire insertion tube 14, thereby facilitating positioning of the guidewire insertion tube 14 relative to the distal tip 16.

[0051] An X-ray transmission hole 40 is formed in the front end tip 16, extending vertically through the bottom wall of the tube mounting groove 38. The X-ray transmission hole 40 is an elongated through-hole formed in the axial direction with a long side, and the front end reaches the wall surface of the front end side of the front end lumen 34, that is, the closed wall surface 42 (described later), and the base end reaches the base end of the front end tip 16. In short, the X-ray transmission hole 40 is continuously provided from the middle of the axial direction of the front end tip 16 to the base end and is open toward the base end. The X-ray transmission hole 40 of this embodiment is formed to have a substantially constant width dimension from the front end to the base end, but the width dimension may also increase from the front end toward the base end, for example.

[0052] A suction opening 44 is formed in the large diameter portion 28 of the front end tip 16. The suction opening 44 is formed by cutting off the peripheral wall of the front end lumen 34 in the large diameter portion 28 in a part of the circumferential direction. Figure 6As shown, the central part in the left-right direction is open upward. The suction opening portion 44 is provided at the front end portion of the front end tube cavity 34, and the front end of the front end tube cavity 34 is opened toward the side (upward) on the outer peripheral surface of the front end tip 16 through the suction opening portion 44, and does not extend closer to the front end side than the suction opening portion 44, and the front end side is closed by the closed wall surface 42. Therefore, in the present embodiment, the front end opening of the front end tube cavity 34 is not open toward the front, but only opens toward the top. The suction opening portion 44 is preferably formed into a shape that can be formed by dividing into a mold in the left-right direction when the mold of the front end tip 16 is formed. In the present embodiment, the upper surface of the opening peripheral portion of the suction opening portion 44 extends approximately parallel to the left-right direction.

[0053] The maximum depth dimension D of the suction opening 44 is preferably set to 0.5 mm ≤ D ≤ 1.2 mm, for example, 0.8 mm. Furthermore, the axial length dimension L of the suction opening 44 is preferably 5 mm ≤ L ≤ 20 mm, more preferably 8 mm ≤ L ≤ 15 mm. By setting the maximum depth dimension D and the axial length dimension L of the suction opening 44 within the above ranges, a high suction force can be achieved when aspirating blood containing a thrombus at a suction pressure of 600 mmHg, and a large thrombus can be aspirated without clogging the suction opening 44. This also further reduces the size of the distal tip 16.

[0054] The front end side wall surface 46 of the suction opening 44 is inclined at an angle α with respect to the axial direction (see Figure 3 ) is greater than the inclination angle β of the base end side wall surface 48 of the suction opening 44 relative to the axial direction (refer to Figure 3 The inclination angle α of the front end side wall surface 46 of the suction opening 44 relative to the axial direction is preferably 30 degrees ≤ α ≤ 75 degrees, and is set to approximately 45 degrees in this embodiment. The closed wall surface 42 continuous with the front end side wall surface 46 extends in a direction substantially perpendicular to the axis, and the boundary portion between the front end side wall surface 46 and the closed wall surface 42 is Figure 3 The method shown here forms a corner. On the other hand, the base end side wall surface 48 is smoothly continuous with the upper surfaces of the left and right sides of the opening periphery of the suction opening 44 without forming any corners. Furthermore, the distal end side wall surface 46 and the closed wall surface 42 are both formed as substantially flat surfaces in this embodiment, but they can also be formed as curved surfaces, or have concavities and convexities, etc.

[0055] In the present embodiment, the tube assembly groove 38 is formed to open downward on the outer circumferential surface of the front end tip 16, and the suction opening portion 44 is formed to open upward on the outer circumferential surface of the front end tip 16. Thus, the tube assembly groove 38 and the suction opening portion 44 are arranged at positions that are offset from each other in the circumferential direction of the front end tip 16. In addition, the front end portion of the X-ray transmission hole 40 that passes through the bottom wall portion of the tube assembly groove 38 is approximately opposite to the suction opening portion 44 in the radial direction of the front end lumen 34, and overlaps with the suction opening portion 44 in the vertical direction. In the present embodiment, the width dimension of the suction opening portion 44 is larger than the width dimension of the X-ray transmission hole 40. However, the suction opening portion 44 and the X-ray transmission hole 40 can have approximately the same width dimension, or the X-ray transmission hole 40 can be set to have a width larger than the suction opening portion 44.

[0056] A thrombus-disrupting wall portion 50 is provided between the small-diameter portion 26 and the large-diameter portion 28. The proximal end surface of the thrombus-disrupting wall portion 50 is formed by the closed wall surface 42 and the distal wall surface 46. The thrombus-disrupting wall portion 50 has an axial thickness greater than the thickness of the peripheral wall portion of the distal lumen 34, resulting in greater deformation rigidity. The conical portion 32 of the small-diameter portion 26 is integrally formed and continuous with the distal end of the thrombus-disrupting wall portion 50, and the suction opening 44 opens proximally to the thrombus-disrupting wall portion 50.

[0057] Furthermore, the front end face of the suction tube 12 abuts against the base end face of the front end tip 16, and the guide wire insertion tube 14 is inserted into the tube mounting groove 38 of the front end tip 16. A shield tube 52 for welding is externally inserted into the thin-walled connecting portion 36 of the suction tube 12, the guide wire insertion tube 14, and the front end tip 16 so as to span the abutment portion of the front end face of the suction tube 12 and the base end face of the front end tip 16 in the axial direction. Furthermore, the shield tube 52 is heated and melted by a laser or the like and then cooled and solidified, thereby fixing the suction tube 12, the guide wire insertion tube 14, and the front end tip 16 to each other via the shield tube 52. Thus, the front end tip 16 is attached to the front end portions of the suction tube 12 and the guide wire insertion tube 14.

[0058] In addition, the guidewire insertion tube 14 can be directly fixed to the front end tip 16 by means of welding, bonding, etc. In particular, since the guidewire insertion tube 14 extends much further than the suction tube 12 on the front end side, the guidewire insertion tube 14 on the front end side relative to the shield tube 52 is preferably fixed to the front end tip 16 by means of welding, bonding, etc. In addition, the suction tube 12 and the guidewire insertion tube 14 on the base end side relative to the shield tube 52 are inserted into the main tube 54, thereby positioning each other. In this embodiment, the main tube 54 and the shield tube 52 are formed of the same material as each other and are integrated by the shield tube 52 solidifying after melting, but in the figure, the boundary line is shown for ease of understanding.

[0059] The distal tip 16 is connected to the suction tube 12 in an axially abutting state, thereby communicating the distal lumen 34 of the distal tip 16 with the suction lumen 18 of the suction tube 12. The proximal opening of the distal lumen 34 and the distal opening of the suction lumen 18 differ in shape and size. When the distal tip 16 is in abutment with the suction tube 12, the proximal opening of the distal lumen 34 is partially open toward the proximal end on both the left and right sides of the suction tube 12. Furthermore, this open portion of the proximal opening of the distal lumen 34 is sealed by the shield tube 52, which is melted and deformed, when the distal tip 16 and the suction tube 12 are joined together.

[0060] The guidewire insertion tube 14 is inserted into the tube mounting groove 38 of the distal tip 16 and secured thereto, thereby covering the X-ray transmission hole 40 extending through the bottom wall of the tube mounting groove 38 with the guidewire insertion tube 14. Thus, the X-ray transmission hole 40, which extends through a portion of the peripheral wall of the distal lumen 34, is sealed by the guidewire insertion tube 14. This prevents negative pressure applied to the distal lumen 34 from escaping through the X-ray transmission hole 40, and allows efficient suction of the thrombus from the suction opening 44. From the perspective of ensuring suction force, the X-ray transmission hole 40 is preferably sealed fluid-tightly by the guidewire insertion tube 14. However, as long as a thrombus of a size to be removed cannot pass through the X-ray transmission hole 40, the opening of the X-ray transmission hole 40 may be narrowed by the guidewire insertion tube 14. In this embodiment, the width of the X-ray transmission hole 40 gradually increases from the distal end toward the proximal end. In the portion overlapping with the suction opening 44, the X-ray transmission hole 40 is closed by the guidewire insertion tube 14. Furthermore, on the proximal side of the suction opening 44, the X-ray transmission hole 40 is formed so that both left and right sides of the guidewire insertion tube 14 are open, and these open portions are closed by the cover tube 52. However, the entire X-ray transmission hole 40 may be closed by the guidewire insertion tube 14.

[0061] exist Figure 3 A guidewire 56, shown virtually in dashed double-dashed lines, is inserted through the guidewire lumen 24 of the guidewire insertion tube 14. The thrombus aspiration catheter 10 of this embodiment, constructed in this manner, is moved within the blood vessel to the lesion site along the guidewire 56, which has been previously inserted into the blood vessel. The distal end of the distal tip 16 of this embodiment is formed into a tapered small-diameter portion 26, thereby achieving excellent passability through blood vessels and facilitating insertion into the lesion site. The position of the thrombus aspiration catheter 10 within the blood vessel can be determined based on the length of the thrombus aspiration catheter 10 and can also be confirmed by X-ray imaging of the distal tip 16.

[0062] Furthermore, when the suction opening 44 of the distal tip 16 has reached the lesion site containing a thrombus, a negative pressure source such as a pump connected to the proximal end of the suction lumen 18 reduces the internal pressure of the distal lumen 34 and the suction lumen 18, causing a suction force to act on the blood within the blood vessel through the suction opening 44. As a result, blood containing the thrombus is drawn from the blood vessel into the distal lumen 34 and the suction lumen 18, thereby treating a stenotic lesion caused by the thrombus. Furthermore, the thrombus and blood recovered within the suction lumen 18 are discharged from the suction lumen 18 via a discharge line connected to the proximal end of the suction lumen 18.

[0063] The suction opening 44 connected to the suction lumen 18 opens laterally in the distal tip 16. This effectively applies suction force to thrombi adhering to the sides of the blood vessel wall, enabling efficient aspiration and removal of the thrombi. In particular, the distal end of the distal lumen 34 is sealed by the sealing wall 42, leaving no opening at the distal end of the distal tip 16. This allows the suction force to be concentrated on the suction opening 44. Furthermore, by rotating the distal tip 16 within the blood vessel, the opening direction of the suction opening 44 is circumferentially changed, enabling aspiration and removal of thrombi adhering to the blood vessel wall throughout the entire circumference.

[0064] The front end tip 16 is formed independently from the suction tube 12 and the guidewire insertion tube 14, thereby increasing the design freedom of the shape. This allows for the formation of a tapered small-diameter portion 26 that advantageously ensures insertability into a blood vessel, a suction opening 44 that opens to the side, and the like. In particular, the front end tip 16 of this embodiment can be formed using a mold such as injection molding, thereby increasing the degree of freedom of shape. Furthermore, the guidewire lumen, which has a small diameter and is difficult to form using mold molding, is not provided in the front end tip 16, thereby avoiding the restriction of the small diameter lumen on the shape freedom of the front end tip 16. Therefore, the front end tip 16 can be obtained with a greater degree of design freedom to meet the desired performance requirements, enabling excellent thrombus aspiration performance, etc.

[0065] The opening direction of the suction opening portion 44 in the front end tip 16 is formed so as to be easily confirmed under X-ray fluoroscopy. That is, when the opening direction of the suction opening portion 44 is consistent with the X-ray fluoroscopy direction, in other words, when the X-ray fluoroscopy direction is the up-down direction of the thrombus aspiration catheter 10, the suction opening portion 44 and the X-ray transmission hole 40 overlap with each other in the X-ray fluoroscopy direction. As a result, in these portions where the suction opening portion 44 and the X-ray transmission hole 40 overlap, the absorption of X-rays by the front end tip 16 made of X-ray opaque resin is suppressed, and the transmittance of X-rays becomes high. Therefore, as shown in FIG. Figure 11AAs shown in FIG. 1 , the contrast of the front end tip 16 is thinned at the suction opening 44. Therefore, under X-ray fluoroscopy, if there is a portion where the contrast is thinned, the suction opening 44 is opened to either side of the fluoroscopy direction. On the other hand, if the opening direction of the suction opening 44 is different from the X-ray fluoroscopy direction, no X-rays are transmitted through the suction opening 44 and the X-ray transmission hole 40. Figure 11B As shown, the contrast becomes thicker. Thus, under X-ray fluoroscopy, where clear imaging is difficult to obtain, the opening direction of the suction opening 44 can be identified by the contrast density within the distal tip 16. This allows for easy control of the opening direction of the suction opening 44 and application of suction force in the desired direction. Furthermore, while the X-ray transmission hole 40 is covered by the guidewire insertion tube 14, the guidewire insertion tube 14 has a higher X-ray transmittance than the distal tip 16, making it less likely to affect the contrast under X-ray fluoroscopy.

[0066] The distal tip 16 of this embodiment includes a thrombus-disrupting wall portion 50 at the distal end of the suction opening 44. With the thrombus-disrupting wall portion 50 positioned close to the blood vessel wall, the thrombus aspiration catheter 10 is moved proximally (proximally) toward the thrombus. This allows the thrombus-disrupting wall portion 50 to contact the thrombus adhered to the blood vessel wall, thereby scraping the thrombus away from the blood vessel wall. This also allows the recovery of thrombi that are firmly attached to the blood vessel wall and cannot be recovered by suction alone, thereby enhancing the effectiveness of thrombus aspiration therapy.

[0067] In particular, in this embodiment, the thrombus-disrupting wall portion 50 is configured such that the distal end side wall surface 46, which forms the contact surface with the thrombus, has a large inclination angle α relative to the axial direction. This shape allows for effective force to be applied to thrombi adhering to the vascular wall by axial movement toward the proximal end of the thrombus aspiration catheter 10. Consequently, the thrombus-disrupting wall portion 50 effectively achieves a thrombus-disrupting effect, enabling efficient removal of thrombi adhering to the vascular wall.

[0068] As described above, the distal wall surface 46 located on the distal side of the aspiration opening 44 is formed to have a large inclination angle α with respect to the axial direction. Meanwhile, the proximal wall surface 48 located on the proximal side of the aspiration opening 44 is formed to have an inclination angle β with respect to the axial direction that is smaller than the inclination angle α. Consequently, when the thrombus aspiration catheter 10 is inserted into a blood vessel and advanced distally, the proximal wall surface 48 is less likely to become caught on the inner circumferential surface of the blood vessel, etc., allowing smooth advancement of the thrombus aspiration catheter 10.

[0069] Furthermore, the thrombus-disintegrating wall 50 is formed to be thickest at the distal tip 16, providing excellent visibility under X-ray fluoroscopy. Such a thrombus-disintegrating wall 50 disposed on the distal side of the suction opening 44 makes it easier to determine the distal position of the suction opening 44 under X-ray fluoroscopy.

[0070] The thrombus aspiration catheter 10 may be provided with Figure 3 The control mechanism 58 is virtually represented by a double-dotted line. The control mechanism 58 includes, for example: a control wire 60, which is inserted into the front end portion of the suction tube 12; and a fixing portion 62, which is provided on the inner circumferential surface of the front end portion of the suction tube 12 to fix the front end of the control wire 60 to the suction tube 12. Moreover, the operating force from the outside, which is input to the base end side of the control wire 60, is applied from the control wire 60 to the suction tube 12, whereby the control mechanism 58 can bend and deform the front end portion of the suction tube 12 and the front end portion of the guidewire insertion tube 14. Thus, the opening direction of the suction opening portion 44 can be changed by the control mechanism 58, so that the suction force can act efficiently on the thrombus. In addition, as the control mechanism 58, for example, the structure disclosed in International Publication No. 2018 / 061598 can be adopted, and a detailed description is omitted here.

[0071] Figure 12 A thrombus aspiration catheter 70 is shown as a second embodiment of the present invention. The thrombus aspiration catheter 70 has a structure in which a distal tip 72 is attached to an aspiration tube 74 and the distal end of a guidewire insertion tube 14. In the following description, components and locations substantially identical to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted.

[0072] The large diameter portion 75 of the distal tip 72 has an axial length longer than that of the large diameter portion 28 of the first embodiment. In particular, a tube connection portion 76 is provided that extends toward the proximal end. The tube connection portion 76 forms the proximal end of the large diameter portion 75 and is slightly larger than the distal end. Furthermore, the large diameter portion 75 of this embodiment does not have the thin-walled connection portion 36 of the first embodiment.

[0073] The suction tube 74 is inserted into the inner circumference of the tube connection portion 76 of the front end tip 72. Moreover, the tube connection portion 76 and the suction tube 74 are fixed to each other by means such as welding or bonding. The suction tube 74 of this embodiment has a two-layer structure of a peripheral wall in which an inner layer 22 made of a resin material is provided on the inner side of a braided layer 20 made of a braided body. The front end portion of the suction tube 74 overlapping the inner circumferential surface of the tube connection portion 76 protrudes from the main pipe 54 toward the front end side, and the braided layer 20 is exposed to the outer circumference. The main pipe 54 is closer to the base end side than the tube connection portion 76 of the front end tip 72, and the main pipe 54 is not inserted into the tube connection portion 76. Therefore, it is possible to achieve both a reduced diameter of the tube connection portion 76 and a guaranteed inner diameter size of the suction tube 74.

[0074] As shown in this embodiment, the connection structure between the aspiration tube and the distal tip is not limited to the structure using the cover tube 52 as in the first embodiment. According to the thrombus aspiration catheter 70 of this embodiment, the cover tube 52 is not required, thereby reducing the number of components. Furthermore, the distal end of the aspiration tube 74 is inserted into the tube connection portion 76 of the distal tip 72, thereby facilitating the positioning of the distal tip 72 and the aspiration tube 74.

[0075] Furthermore, by increasing the inner diameter of the front end tip 72 in the tube connection portion 76, the front end tip 72 is prevented from being enlarged, while allowing the suction tube 74 to be enlarged. In this case, if a step is formed on the inner circumferential surface of the front end tip 72 on the front end side of the tube connection portion 76, the front end surface of the suction tube 74 abuts against the step, thereby simplifying the axial positioning of the front end tip 72 and the suction tube 74.

[0076] While the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific descriptions. For example, the material forming the distal tip 16 is not limited to the materials exemplified in the aforementioned embodiments. Specifically, the material forming the distal tip 16, i.e., the radiopaque material, is not limited to the bismuth oxide exemplified in the aforementioned embodiments; it can be appropriately selected and employed from various known contrast agents, such as platinum, tungsten, bismuth subcarbonate, and barium sulfate.

[0077] In the embodiment, the suction opening portion 44 is exemplified as having an opening shape of a long strip with the axial direction as the long side, but the opening shape of the suction opening portion 44 is not particularly limited. For example, the axial dimension can be smaller than the circumferential width dimension, or it can be formed into a circular point shape.

[0078] In the above embodiment, a structure is illustrated in which the suction opening 44 is open to the side of the distal tip 16. However, for example, the suction opening connected to the distal end of the suction lumen 18 may also be open to the front of the distal tip 16. Furthermore, multiple distal openings, i.e., suction openings, of the distal lumen 16 may be provided. For example, in addition to the suction opening 44 opening to the side, a suction opening opening opening to the front may also be provided. In the case of multiple suction openings, for example, these suction openings can be selectively opened and closed, thereby achieving efficient suction force.

[0079] Preferably, the suction opening 44 is located on the radially opposite side of the tube mounting groove 38. These suction openings 44 and the tube mounting groove 38 can be arranged at different positions on the circumference of the front end tip 16. For example, the opening direction of the suction opening 44 and the opening direction of the tube mounting groove 38 can be set to a direction that deviates by approximately 90 degrees on the circumference of the front end tip 16.

[0080] The X-ray transmission hole 40 does not need to reach the base end of the distal end tip 16 , and may be provided, for example, penetrating midway in the axial direction of the distal end tip 16 .

[0081] The front end tip 16 preferably has a small diameter portion 26 and a large diameter portion 28, and the front end portion is formed into a structure with a smaller diameter than the base end portion, but the front end tip may not need to have a small diameter portion and a large diameter portion, for example, the outer diameter of the front end tip can be roughly constant throughout the entire axial direction.

[0082] The distal tip can also be multi-colored, for example, by using two or more materials. By making the distal tip partially different in material, for example, by making the distal tip partially different in X-ray transmittance, it is easier to determine the opening direction of the suction opening during X-ray fluoroscopy of the distal tip. It is also easier to achieve both excellent flexibility of the catheter distal end and shape stability of the distal lumen 34.

[0083] Description of Reference Numerals

[0084] 10: Thrombus aspiration catheter (first embodiment);

[0085] 12: Suction tube;

[0086] 14: Guide wire insertion tube;

[0087] 16: front end tip;

[0088] 18: Suction lumen;

[0089] 20: Braided layer;

[0090] 22: inner layer;

[0091] 24: guidewire lumen;

[0092] 26: Trail section;

[0093] 28: Large diameter part;

[0094] 30: semi-cylindrical part;

[0095] 32: cone;

[0096] 34: anterior lumen;

[0097] 36: thin-walled connection;

[0098] 38: pipe assembly groove;

[0099] 40: X-ray transmission hole;

[0100] 42: Closed wall;

[0101] 44: suction opening;

[0102] 46: front end side wall;

[0103] 48: base end side wall;

[0104] 50: thrombus wall fragmentation;

[0105] 52: hood tube;

[0106] 54: Supervisor;

[0107] 56: guide wire;

[0108] 58: Control mechanism;

[0109] 60: control line;

[0110] 62: fixed part;

[0111] 70: Thrombus aspiration catheter (second embodiment);

[0112] 72: front end;

[0113] 74: Suction tube;

[0114] 75: Large diameter part;

[0115] 76: Pipe connection part.

Claims

1. A thrombus aspiration catheter, comprising: an aspiration tube having an aspiration lumen for aspirating thrombus in a blood vessel; a guidewire insertion tube having a guidewire lumen for inserting a guidewire; and The front end tip is installed at the front end of the suction tube and the guide wire insertion tube, and has a front end lumen communicating with the suction lumen of the suction tube. in, The front end tip is provided with a tube mounting groove extending in the axial direction on the outer peripheral surface, and the guide wire insertion tube independent of the front end tip is inserted into the tube mounting groove and fixed to the front end tip.

2. The thrombus aspiration catheter according to claim 1, wherein: The front end lumen has a suction opening portion opened toward the side on the outer peripheral surface of the front end tip, and a closed wall surface is provided at the front end side of the suction opening portion in the front end tip to close the front end side of the front end lumen, The tube attachment groove is arranged at a position offset from the suction opening in the circumferential direction of the front end tip.

3. The thrombus aspiration catheter according to claim 2, wherein: The front end portion of the front end tip is formed as a small diameter portion including a tapered conical portion, and the base end portion of the front end tip is formed as a cylindrical large diameter portion having a larger diameter than the small diameter portion, and the suction opening portion opens in the large diameter portion.

4. The thrombus aspiration catheter according to claim 2 or 3, wherein: The front end tip is formed of a resin material mixed with an X-ray opaque material, and An X-ray transmission hole penetrating through the bottom wall of the tube attachment groove is formed at the front end tip at a position overlapping with the suction opening in the radial direction of the front end tip.

5. The thrombus aspiration catheter according to claim 2 or 3, wherein: The inclination angle of the front end side wall surface of the suction opening portion relative to the axial direction of the front end tip is larger than the inclination angle of the base end side wall surface of the suction opening portion relative to the axial direction of the front end tip.

6. The thrombus aspiration catheter according to claim 1 or 2, wherein: The thrombus aspiration catheter includes a control mechanism that applies an external operating force to bend and deform the distal ends of the aspiration tube and the guidewire insertion tube.

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