Distal stabilizer

Abstract

A distal stabilizer 1 for use in catheter delivery in a living body lumen is provided with: a linear delivery member; and a cylindrical part 2 connected to the linear delivery member and locked to the inner wall of the living body lumen. The cylindrical part 2 includes a body part 11 having a mesh pattern structure in which cells 20 having a shape surrounded by wire members are arranged along at least the major axis direction. At least one of the cells 20 forming the body part 11 has at least one open cell part 21 in which two wire members are connected at the top part 25. In at least one of the open cell parts 21, in a reduced diameter state, the two wire members extend along the major axis direction, and, in a natural state, the top part 25 protrudes along the circumferential direction orthogonal to the major axis direction.

Description

TECHNICAL FIELD

[0001] The present invention relates to, for example, a distal stabilizer used for catheter delivery in a biological lumen.

BACKGROUND ART

[0002] In a biological lumen such as a patient's artery, a treatment device is delivered to a target position by using a catheter whose distal end is guided to the vicinity of the target position, whereby treatment with the treatment device or treatment in which the catheter itself is used as a treatment device is performed. For example, Patent Document 1 discloses an anchor device (distal stabilizer) in which a cylindrical portion is joined to the distal end of a delivery wire. When this cylindrical portion is released from the microcatheter and expanded, the cylindrical portion is anchored to the inner wall of the biological lumen. Therefore, the operation of delivering the target catheter externally inserted over the microcatheter to the vicinity of the target position can be easily performed. In addition, Patent Document 2 discloses a distal stabilizer in which the free convex ends of the open cell portions protrude only to the distal side. According to this distal stabilizer, by having the open cell portions, it has excellent anchoring force to the inner wall of the biological lumen and also has the property of easily following the bending of the biological lumen.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] Most target catheters extrapolated to microcatheters have a large outer diameter and high rigidity. Therefore, as the target catheter advances, it repeatedly applies forces that pull the less rigid microcatheter or delivery wire proximally. In particular, if the blood vessel, which is a biological lumen, contains highly curved or tortuous vessels, the target catheter is likely to get caught in the curves and branching points, and when force is applied to pass through these sections, forces are repeatedly applied that pull the microcatheter or delivery wire proximally.

[0005] When a force is applied to pull the delivery wire proximal, the position of the cylindrical portion locked to the inner wall of the biological lumen may shift proximal. This displacement of the cylindrical portion occurs not only when delivering the target catheter to the vicinity of the target position, but also when re-sheathing the cylindrical portion locked to the inner wall of the biological lumen onto the catheter. If the position of the cylindrical portion locked in the biological lumen shifts proximal, it becomes difficult to deliver the tip of the target catheter to the vicinity of the target position. To suppress the displacement of the cylindrical portion, it is conceivable to increase the expansion force (the force supporting the blood vessel) of the cylindrical portion. However, increasing the expansion force of the cylindrical portion not only increases the burden on the blood vessel wall, but also increases the sliding resistance with the inner wall of the microcatheter, thus reducing the pushability of the cylindrical portion. This decrease in pushability of the cylindrical portion occurs, for example, when delivering the cylindrical portion distally in highly curved, tortuous blood vessels. Thus, improving pushability is a challenge that arises not only when the expansion force of the cylindrical portion is increased, but also with cylindrical portions that have a normal expansion force. The distal stabilizer described in Patent Document 2, mentioned above, has the problem that it is difficult to improve the pushability of the cylindrical portion because the free convex end of the open cell portion protrudes only on the distal side.

[0006] The object of the present invention is to provide a distal stabilizer that has an open cell portion, suppresses displacement of the cylindrical portion locked in a biological lumen, and further improves the pushability of the cylindrical portion. [Means for solving the problem]

[0007] First Disclosure: A distal stabilizer used for catheter delivery in a biological lumen, comprising: a linear delivery member; and a cylindrical portion connected to the linear delivery member and locked to the inner wall of a biological lumen, wherein the cylindrical portion comprises a main body having a mesh pattern structure in which cells surrounded by wire-like members are arranged at least along the longitudinal axis, and at least one of the cells forming the main body has at least one open cell portion in which two wire-like members are connected at the top, and at least one of the open cell portions has two wire-like members extending along the longitudinal axis in a reduced diameter state, and the top of the open cell portion protrudes along the circumferential direction perpendicular to the longitudinal axis in a natural state.

[0008] Second disclosure: The distal stabilizer according to the first disclosure, wherein the open cell portion, in its natural state, has its top protruding in a direction of +30° to -30° with respect to the circumferential direction of the cylindrical portion.

[0009] Third disclosure: The distal stabilizer according to the first or second disclosure, wherein the open cell portion is provided in at least one of the cells located at the distal end of the main body in the longitudinal direction.

[0010] Fourth disclosure: The distal stabilizer according to the first or second disclosure, wherein the open cell portion is provided in at least one of the cells located at the proximal end in the longitudinal direction of the main body.

[0011] Fifth disclosure: The distal stabilizer according to the first or second disclosure, wherein the open cell portion is provided in at least one cell located between the distal end and the proximal end in the longitudinal direction of the main body.

[0012] Sixth disclosure: The distal stabilizer according to the first or second disclosure, wherein the open cell portion is also provided in an antenna portion that connects the proximal end of the main body to the linear delivery member.

[0013] Seventh Disclosure: The distal stabilizer according to the first or second disclosure, wherein at least one of the cells having the open cell portion has an open cell portion in which, in a reduced diameter state, a portion of the wire-like member does not substantially extend along the longitudinal axis, and in a natural state, a portion of the wire-like member protrudes along a circumferential direction perpendicular to the longitudinal axis.

[0014] Eighth disclosure: The distal stabilizer according to the first or second disclosure, wherein at least one of the cells having the open cell portion has an open cell portion such that in the reduced diameter state and the natural state, a portion of the wire-like member does not substantially extend along the longitudinal axis.

[0015] Ninth disclosure: The distal stabilizer according to the first or second disclosure, wherein the cylindrical portion has a structure in which the cells are arranged spirally with respect to the longitudinal axis.

[0016] Tenth disclosure: The distal stabilizer according to the first or second disclosure, which is used for applications where it is temporarily placed in a biological lumen and then retrieved outside the body.

[0017] Eleventh Disclosure: A catheter delivery method comprising a linear delivery member, a distal stabilizer extending from the distal end of the linear delivery member and having a cylindrical portion that can be locked to the inner wall of a biological lumen, a small catheter capable of housing the cylindrical portion in a reduced diameter state together with the linear delivery member, and at least one large catheter externally fitted to the linear delivery member or the small catheter, the method comprising: a first step of releasing the cylindrical portion housed in the small catheter in a reduced diameter state from the distal end of the small catheter and locking it to the inner wall distal to the target position of the biological lumen; and a second step of retracting the small catheter proximal to the biological A catheter delivery method comprising: a second step of exposing the catheter in a lumen; and a third step of advancing the large catheter distally with the large catheter extrapolated onto the linear delivery member and positioning it at a target location in a biological lumen, wherein in the first step, there is one or more bends in the biological lumen between the target location where the target catheter is positioned and the position where the cylindrical portion is locked; and at least at the start of the third step, the linear delivery member is retracted proximally, and with the exposed portion of the linear delivery member in contact with one or more bends in the biological lumen, the large catheter is advanced distally with the large catheter extrapolated onto the linear delivery member.

[0018] Twelfth Disclosure: A method for delivering a catheter system according to the eleventh disclosure, wherein in the first step, the cylindrical portion is engaged with the inner wall of a more bendable biological lumen among a plurality of biological lumens that branch at a branching site distal to the target location.

[0019] Thirteenth Disclosure: A method for delivering a catheter system according to the eleventh or twelfth disclosure, wherein, in the first step, the cylindrical portion is engaged distal to the target location of the biological lumen, and the exposed portion of the linear delivery member is engaged at a position that spans one or more bends or branches of the biological lumen.

[0020] Fourteenth Disclosure: A catheter delivery method comprising a linear delivery member, a distal stabilizer extending from the distal end of the linear delivery member and having a cylindrical portion that can be locked to the inner wall of a biological lumen, a small catheter capable of housing the cylindrical portion in a reduced diameter state together with the linear delivery member, and at least one large catheter extrapolated to the small catheter, the method comprising: a first step of releasing the cylindrical portion housed in the small catheter in a reduced diameter state from the distal end of the small catheter and locking it to the inner wall distal to the target position of the biological lumen; a second step of retracting the small catheter proximal to expose the linear delivery member in the biological lumen; and advancing the large catheter distally while extrapolated to the linear delivery member to the target position in the biological lumen. A method for delivering a therapeutic device, comprising: a third step of positioning; a fourth step of reducing the diameter of the cylindrical portion and storing it in a retrieval catheter and withdrawing it from the biological lumen; and a fifth step of inserting the therapeutic device into the large catheter and advancing it distally, and delivering it to the target position by pushing it out of the large catheter at the target position, wherein in the first step, there is one or more bends in the biological lumen between the target position where the target catheter is positioned and the position where the cylindrical portion is locked, and at least at the start of the third step, the linear delivery member is pulled proximally, and with the exposed portion of the linear delivery member in contact with one or more bends in the biological lumen, the large catheter is advanced distally with the linear delivery member externally inserted.

[0021] Fifteenth disclosure: A method for delivering a therapeutic device according to the fourteenth disclosure, wherein in the first step, the cylindrical portion is engaged with the inner wall of a more bendable biological lumen among a plurality of biological lumens that branch at a branching site distal to the target location.

[0022] Sixteenth Disclosure: A method for delivering a therapeutic device according to the Fourteenth or Fifteenth Disclosure, wherein in the first step, the cylindrical portion is engaged at a position distal to the target location of the biological lumen, and the exposed portion of the linear delivery member spans one or more bends or branches of the biological lumen.

[0023] Seventeenth disclosure: A treatment method using a catheter system comprising a linear delivery member, a distal stabilizer extending from the distal end of the linear delivery member and having a cylindrical portion engageable with the inner wall of a biological lumen, a small catheter capable of accommodating the cylindrical portion in a reduced-diameter state together with the linear delivery member, and at least one large catheter externally fitted onto the small catheter, the treatment method comprising: a first step of releasing the cylindrical portion, which is accommodated in the small catheter in a reduced-diameter state, from the distal end of the small catheter and engaging the cylindrical portion with the inner wall on the distal side of the target position in the biological lumen; a second step of retracting the small catheter to the proximal side to expose the linear delivery member in the biological lumen; a third step of advancing the large catheter distally in a state of being externally fitted onto the linear delivery member, and disposing the large catheter at a target position in the biological lumen; a fourth step of reducing the diameter of the cylindrical portion to accommodate it in a recovery catheter, and withdrawing it out of the biological lumen; a fifth step of inserting a treatment device into the large catheter, advancing the treatment device distally, and pushing the treatment device out of the large catheter at the target position, thereby delivering the treatment device to the target position; and a sixth step of performing treatment using the treatment device delivered to the target position. In the second step, one or more bent portions of the biological lumen exist between the target position where the target catheter is disposed and the position where the cylindrical portion is engaged, and at least at the start of the third step, the linear delivery member is retracted to the proximal side, and in a state where the exposed portion of the linear delivery member is in contact with the one or more bent portions of the biological lumen, the large catheter is advanced distally in a state of being externally fitted onto the linear delivery member.

[0024] Eighteenth disclosure: The treatment method using the catheter system according to the seventeenth disclosure, wherein in the first step, the cylindrical portion is engaged with the inner wall of a biological lumen with a larger bend among a plurality of biological lumens that branch at a branch site located distal to the target position.

[0025] Nineteenth disclosure: The treatment method using the catheter system according to the seventeenth disclosure or the eighteenth disclosure, wherein in the first step, the cylindrical portion is locked at a position that is distal to the target position in the biological lumen and where the exposed portion of the linear delivery member straddles one or more bent sites or branched sites of the biological lumen.

[0026] In the eleventh disclosure, the fourteenth disclosure, and the seventeenth disclosure described above, the cylindrical portion may have the same mesh pattern structure as the cylindrical portion of the first disclosure, or may have a different structure. For example, the free protruding end (described later) of the open cell portion of the cylindrical portion may protrude only to the proximal side, or open cell portions whose free protruding ends protrude to the distal side and open cell portions whose free protruding ends protrude to the proximal side may coexist. Further, the cylindrical portion may have a mixture of open cell portions and closed cell portions, or may be composed only of closed cell portions. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide a distal stabilizer that has an open cell portion, suppresses positional displacement of the cylindrical portion locked in a biological lumen, and further improves the pushability of the cylindrical portion. [Brief Description of the Drawings]

[0028] [Figure 1] It is a diagram showing a delivery system 10 provided with a distal stabilizer 1 according to an embodiment. [Figure 2] It is a diagram of the locking stent 2 of the first configuration in a state virtually developed on a plane, viewed from the inner side. [Figure 3A] It is a diagram of the locking stent 2 in a reduced-diameter state in a state virtually developed on a plane, viewed from the inner side. [Figure 3B] It is a diagram of a general locking stent in a reduced-diameter state in a state virtually developed on a plane, viewed from the inner side. [Figure 4] It is a conceptual diagram illustrating the direction in which the top portion 25 of the open cell portion 21 protrudes relative to the circumferential direction RD. [Figure 5]This is a view from the inside of the second configuration's locking stent 2, virtually unfolded on a plane. [Figure 6] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 7] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 8] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 9] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 10] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 11] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 12] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 13] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 14] This is a schematic diagram showing a first example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 15] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 16] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 17] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 18] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 19] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 20] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 21] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Figure 22] This is a schematic diagram showing a second example of a procedure using a delivery system 10 including a distal stabilizer 1. [Modes for carrying out the invention]

[0029] Embodiments of the distal stabilizer according to the present invention will be described below. Note that the drawings attached to this specification are all schematic or conceptual diagrams, and for ease of understanding, the shape, scale, and aspect ratio of each part have been altered or exaggerated from the actual object. For example, the longitudinal direction of a catheter, etc., is shown as shorter, and the radial direction as thicker. In this specification, terms that specify shape, geometric conditions, and the degree thereof, such as "direction," include not only the strict meaning of the term but also a broader interpretation that can be considered as roughly that direction. Therefore, "~direction" may also be referred to as "~side" as appropriate.

[0030] In this specification, the longitudinal axis direction when the distal stabilizer 1 is extended in a straight line is also referred to as the "longitudinal axis LD". In the direction of inserting the locking stent 2 (described later) into the catheter, the proximal side of the longitudinal axis LD closer to the operator is designated as "D1", and the distal side further away from the operator is designated as "D2". The direction perpendicular to the longitudinal axis LD is also referred to as the "radial axis RD" or simply "radial direction". When the locking stent 2 is virtually unfolded in a plane (see Figure 2), the radial axis RD corresponds to the circumferential direction of the locking stent 2. Therefore, in the description of the locking stent 2 virtually unfolded in a plane, the "radial axis RD" is also appropriately referred to as the "circumferential axis RD". In the circumferential axis RD, one circumferential direction is designated as the "circumferential axis D3", and the other circumferential direction is designated as the "circumferential axis D4" (see Figures 2 and 5).

[0031] Figure 1 shows a delivery system 10 equipped with a distal stabilizer 1 according to an embodiment. Figure 2 is a view from the inside of a locking stent 2 of the first configuration virtually unfolded on a plane. Figure 3A is a view from the inside of a locking stent 2 in a reduced diameter state virtually unfolded on a plane. Figure 3B is a view from the inside of a general locking stent in a reduced diameter state virtually unfolded on a plane. Figure 4 is a conceptual diagram illustrating the direction in which the top 25 of the open cell portion 21 protrudes relative to the circumferential direction RD.

[0032] The delivery system 10 shown in Figure 1 can be used to deliver therapeutic devices to blood vessels in the luminal structure of the body, such as the anterior cerebral artery (ACA), anterior communicating artery (Acom), and middle cerebral artery (MCA) within the skull. However, the blood vessels in the luminal structure of the body to which the delivery system 10 is used are not limited to the examples above. Blood vessels in the luminal structure of the body may include, for example, blood vessels in the coronary arteries, blood vessels (arteries and veins) of the upper and lower limbs, and organs, in addition to those of the brain. In the following description, the term "luminal structure of the body" will also be used to refer to "blood vessels."

[0033] As shown in Figure 1, the delivery system 10 comprises a distal stabilizer 1 and a plurality of catheters, including a first catheter 5 and a second catheter 6. The first catheter 5 is, for example, a catheter called a microcatheter. The second catheter 6 is extrapolated into the first catheter 5. The second catheter 6 is a large-diameter catheter. The diameter of the first catheter 5 is set according to the target location to which the second catheter 6 is delivered and the inner diameter and curvature of the biological lumen of the path leading thereto. Although not particularly limited, the inner diameter of the first catheter 5 is preferably 0.017 inches or less, more preferably 0.0165 inches or less. As catheters, one or more other catheters (not shown) that are extrapolated into the second catheter 6 may be used as needed. Generally, by using a large number of catheters, it is possible to eventually insert and advance a catheter with a large inner diameter into the biological lumen.

[0034] The distal stabilizer 1 is a device used for catheter delivery in a biological lumen. The distal stabilizer 1 comprises a locking stent (cylindrical portion) 2 and a delivery wire (linear delivery member) 3.

[0035] The locking stent 2 is an anchor device that is inserted into the first catheter 5 in a reduced diameter state and, upon release from the first catheter 5 within the blood vessel, expands and locks onto the inner wall of the biological lumen. "Locking" to the inner wall of the biological lumen means not only that it does not shift from its expanded position within the biological lumen, but also that it allows for a degree of displacement that does not substantially affect catheter delivery. The locking stent 2 is connected to the distal end of the delivery wire 3. Note that the locking stent 2 is not limited to being connected to the distal end of the delivery wire 3; it may also be connected in the middle of the delivery wire 3. As shown in Figure 1, the locking stent 2 comprises a main body 11 and an antenna 12. The main body 11 is cylindrical and has a mesh pattern structure, which will be described later. Figure 1 shows a simplified representation of the main body 11. The antenna 12 is the part that converges the proximal D1 of the main body 11 onto the delivery wire 3.

[0036] As shown in Figure 2, a distal marker 13 is provided at the distal end D2 of the locking stent 2. A proximal marker 14 is provided at the proximal end D1 of the locking stent 2. Each marker is made of radiopaque material. The distal marker 13 is a landmark for confirming the position of the distal end D2 of the locking stent 2. The proximal marker 14 is a landmark for confirming the position of the proximal end D1 of the locking stent 2.

[0037] The main body 11 has a structure in which a plurality of cells 20 are arranged along the longitudinal axis LD of the locking stent 2. In this embodiment, the main body 11 has a mesh pattern structure in which a plurality of cells 20 are arranged spirally with respect to the longitudinal axis LD of the locking stent 2, and is designed to support the inner wall of the biological lumen when expanded in a blood vessel. As shown in Figure 2, the plurality of cells 20 are arranged spirally along the cell arrangement direction (design arrangement direction of the cells) SD, which is inclined with respect to the longitudinal axis LD. In this embodiment, the cell arrangement direction SD is inclined diagonally upward to the right from the distal side D2 to the proximal side D1 of the locking stent 2, as shown in Figure 2 (the direction when the longitudinal axis LD is viewed as the up and down direction in the figure). However, the cell arrangement direction SD is not limited to this. The cell arrangement direction SD may be inclined diagonally upward to the left from the distal side D2 to the proximal side D1 of the locking stent 2 (the opposite direction to that in Figure 2). "Along the cell arrangement direction SD" means parallel or substantially parallel to the cell arrangement direction SD. "Approximately parallel" means, for example, that the angle at which the arrangement direction of cell 20 intersects the cell arrangement direction SD is in the range of approximately 1 to 15°. In the locking stent 2, the angle at which the longitudinal axis LD intersects the cell arrangement direction SD is, for example, less than 45°.

[0038] A cell 20, also called an opening or compartment, refers to a portion surrounded by wire-like struts (wire-like members) 24 that constitute the mesh pattern of the main body 11. As shown in Figure 2, in the locking stent 2 (main body 11) of this embodiment, at least one of the cells 20 has open cell portions 21 and 22.

[0039] Cells 20 having open cell portions 21 and 22 (hereinafter also referred to as "cells 20a") only need to be provided at least once in any region along the long axis LD (distal end, proximal end, or between the distal end and the proximal end). As shown in Figure 2, in the main body 11, cells 20 without open cell portions 21 may be mixed with cells 20a, or all cells located in each region along the long axis LD may be cells 20a. Furthermore, the number of cells 20a in each region may be the same or different. In addition, cells 20a may be provided along the long axis LD or along the circumferential direction RD. In each direction, there may be one cell 20a or multiple cells 20a.

[0040] The open cell portion 21 of cell 20a is the portion where one end of two roughly straight struts 24a and 24b is connected at the apex 25, forming a roughly V shape overall, and where no other strut is connected to the apex 25. The term "roughly straight" does not mean strictly straight, but includes shapes that can be considered nearly straight or roughly straight. In Figure 2, for cell 20a shown in regions A1 and A2, the struts and apex that constitute the open cell portion 21 (21a, 21b) are labeled with reference numerals.

[0041] In the open cell portion 21a shown in region A1 of Figure 2, the other ends of the two struts 24a and 24b are connected to the struts and / or closed cell portion 23 (described later) of the same row extending in the cell arrangement direction SD. On the other hand, the other ends of the struts 24a and 24b are not connected in the cell arrangement direction SD. Therefore, the open cell portion 21 is roughly V-shaped.

[0042] Furthermore, in the open cell portion 21a shown in region B1 of Figure 2, the other ends of the struts 24a and 24b are connected to the other ends of the struts 24a and 24b of the open cell portion 21b(21) of another cell 20a adjacent in the cell arrangement direction SD. In region B1, the top 25 of the open cell portion 21a protrudes generally along the circumferential direction D4. On the other hand, the top 25 of the open cell portion 21b protrudes generally along the circumferential direction D3. In the open cell portion 21a shown in region B1, the other ends of the struts 24a and 24b are not connected in the cell arrangement direction SD. Similarly, in the open cell portion 21b, the other ends of the struts 24a and 24b are not connected in the cell arrangement direction SD. Therefore, the two open cell portions 21a and 21b of two cells 20a adjacent in the cell arrangement direction SD form a roughly rhombus shape as a whole. The open cell portion 21a provided in cell 20a may be a single portion, as shown in region A1, or it may be connected to the open cell portions 21b of other adjacent cells 20a, as shown in region A2.

[0043] The shape of the open cell portion 21 can be, for example, roughly V-shaped, roughly U-shaped, roughly Ω-shaped, etc. Figure 2 shows an example in which one or more open cell portions 21 (21a, 21b) are provided in one cell 20a, but the number and arrangement of open cell portions 21 provided in one cell 20a are not limited to the example in Figure 2.

[0044] In the open cell portion 21 of cell 20a, the direction in which the top portion 25 protrudes is not limited to the downward-sloping or upward-sloping direction to the right, as shown in Figure 2, but may also be downward-sloping or upward-sloping to the left (the direction when the long axis LD is viewed as the vertical direction in the figure). Furthermore, the size of the open cell portion 21 (the virtual area of ​​the space enclosed by the strut) can be appropriately set by the size of the cell 20 in which the open cell portion 21 is provided, the reduction ratio of the locking stent 2, etc. For example, the size of the open cell portion 21 may occupy about half of the entire cell.

[0045] In the open cell portion 21 of cell 20a, when the locking stent 2 is in a reduced diameter state, the two struts 24a and 24b extend along the longitudinal axis LD. The reduced diameter state refers to the state in which the locking stent 2 is reduced in diameter and housed in a catheter (for example, the first catheter 5). Figure 3A shows the two struts 24a and 24b of the open cell portion 21 provided in the antenna portion 12 extending along the longitudinal axis LD. In the antenna portion 12 in the reduced diameter state shown in Figure 3A, the number of struts extending along the longitudinal axis is greater than that of a typical locking stent shown in Figure 3B.

[0046] Furthermore, as a structural requirement to facilitate the extension of struts 24a and 24b along the longitudinal axis LD when the locking stent 2 is in a reduced diameter state, as shown in Figure 4, the angle θa at which the struts 24a and 24b, which are connected in a roughly V-shape, intersect can be in the range of 100° to 160°. In addition, in the open cell portion 21 of cell 20a, it is preferable that the other end of struts 24a and 24b (opposite the top side) is connected to the strut and / or closed cell portion 23 of the same row extending in the cell arrangement direction SD. By satisfying the above structural requirements in the open cell portion 21 of cell 20a, when the locking stent 2 is in a reduced diameter state, struts 24a and 24b can easily extend along the longitudinal axis LD.

[0047] Furthermore, regarding the open cell portion 21 provided on the main body 11, when the locking stent 2 is in a reduced diameter state, the two struts 24a and 24b (see Figure 2) constituting the open cell portion 21 take on a shape (not shown) that extends along the long axis direction LD. On the other hand, as will be described later, when the locking stent 2 is in its natural state, the top portion 25 of the open cell portion 21 of cell 20a protrudes along the circumferential direction RD perpendicular to the long axis direction LD. The natural state refers to the state in which the locking stent 2 is not reduced in diameter (unloaded state).

[0048] As shown in Figure 4, when the locking stent 2 is in its natural state, the top 25 of the open cell portion 21 protrudes along the circumferential direction RD, which is perpendicular to the longitudinal axis LD. Specifically, the top 25 of the open cell portion 21 protrudes in the direction of +θ to -θ with respect to the circumferential direction RD of the main body portion 11 (locking stent 2). In Figure 4, if we define the line that bisects the top 25 of the open cell portion 21 as line L1, which indicates the direction in which the top 25 of the open cell portion 21 protrudes, and define the line parallel to the circumferential direction RD as line L2, and the line parallel to the longitudinal axis LD as line L3, then the angle (θ) at which line L1 of the top 25 of the open cell portion 21 intersects with line L2 parallel to the circumferential direction RD is 0 to +30° in the range of 0 to +θ, and 0 to -30° in the range of 0 to -θ. More preferably, the angle (θ) is 0 to +10° in the range of 0 to +θ, and 0 to -10° in the range of 0 to -θ. When lines L1 and L2 of the top 25 of the open cell portion 21 coincide, the angle (θ) is 0 (zero). The directions "+θ" and "-θ" shown in Figure 4 are added for explanatory purposes, and the directions "+" and "-" are not particularly limited. Also, since Figure 4 is a conceptual diagram, the shape, size, etc. of the open cell portion 21 are not limited to the example shown.

[0049] Furthermore, the top 25 of the open cell portion 21 of the locking stent 2 protrudes along the circumferential direction RD, not only in its natural state but also when it is released from the first catheter 5 within the blood vessel (hereinafter also referred to as the "expanded state"). In the expanded state, the top 25 of the open cell portion 21 of the locking stent 2 protrudes in a direction of +30° to -30° relative to the circumferential direction RD of the main body portion 11.

[0050] Returning to Figure 2, the open cell portion 22 of cell 20 (cell 20a) is the portion where one end of the two struts 24c and 24d are connected at the top 26, and no other strut is connected to the top 26. In Figure 2, for cell 20a located in the center of the figure, the struts and top of the open cell portion 22 are labeled. In the open cell portion 22, the other ends of the two struts 24c and 24d are connected to another strut or to the closed cell portion 23 (described later). In the reduced diameter state and the natural state, the two struts 24c and 24d do not substantially extend along the longitudinal axis LD in the open cell portion 22. Substantially not extending means that even if the two struts were to extend along the longitudinal axis LD, it would not extend to the extent that it would affect the pushability of the locking stent 2.

[0051] The shape of the open cell portion 22 is, for example, roughly V-shaped, roughly U-shaped, roughly Ω-shaped, etc. In the open cell portion 22 of this embodiment, the direction in which the top portion 26 protrudes is generally along the distal side D2 of the longitudinal axis LD, as shown in Figure 2. Since the open cell portion 22 is not easily constrained by other struts, displacement and deformation in the radial direction RD are not easily restricted. Note that the direction in which the top portion 26 of the open cell portion 22 protrudes is not limited to the example in Figure 2, but may also be along the cell arrangement direction SD, for example.

[0052] The closed cell portion 23 of cell 20 (cell 20a) is the portion where the proximal D1 ends of two struts 24e and 24f are connected, and another strut 24g is connected to that connected portion. Like the open cell portion 21 described above, the closed cell portion 23 hardly changes shape in the longitudinal direction LD or circumferential direction RD in the reduced diameter state and the natural state. The shape of the closed cell portion 23 is, for example, roughly V-shaped, roughly U-shaped, roughly Ω-shaped, etc. The protruding direction of the closed cell portion 23 should generally be towards the proximal D1. In this way, the closed cell portion 23 protrudes towards the proximal D1, but outward rebound is suppressed by the other strut 24g, so it is less likely to be an obstacle when resheathing (storing) into the first catheter 5.

[0053] The antenna portion 12 is the part that converges the proximal side D1 of the main body portion 11 to the delivery wire 3, and is connected to the main body portion 11 in the longitudinal direction LD. The antenna portion 12 has a mesh pattern structure similar to the main body portion 11. The antenna portion 12 is designed so that when expanded in a blood vessel, the force supporting the inner wall of the biological lumen is relatively lower than that of the main body portion 11. The antenna portion 12 is composed of a plurality of cells 20 similar to the main body portion 11. The cells 20 constituting the antenna portion 12 include cells 20a having open cell portions 21 and 22, and cells 20 without these portions (hereinafter also referred to as "cell 20b"). Cell 20b is, for example, a cell surrounded by four struts 24 and does not have open cell portions 21 and 22. Note that the cells constituting the antenna portion 12 are not limited to the example of this embodiment, and may include, for example, cells that include either open cell portions 21 or 22, or cells that include either open cell portions 21 or 22 may have or not have closed cell portions 23.

[0054] As shown in Figure 2, in the antenna section 12 of this embodiment, cell 20a has two open cell portions 21, but it may also have one or three or more open cell portions 21, or it may have no open cell portions 21. Furthermore, cells 20a having open cell portions 21 and cells 20 without open cell portions 21 may be mixed. Moreover, the antenna section 12 may be composed of any form of cell, not limited to the example of being composed of cells 20a and 20b, as long as it does not impair the function of the antenna section 12.

[0055] The locking stent 2 can be manufactured, for example, by laser processing a tube formed from a biocompatible material, particularly preferably a superelastic alloy. When manufactured from a superelastic alloy tube, it is preferable to laser process a tube of about 2 to 3 mm in diameter, expand it to the desired diameter, and then apply a shape memory treatment to the tube. The main body 11 can be manufactured not only by laser processing, but also by cutting, for example, or by weaving wire-shaped metal wires into a tubular shape.

[0056] The material for the locking stent 2 is preferably a material that has high rigidity and high biocompatibility. Examples of such materials include titanium, nickel, stainless steel, platinum, gold, silver, copper, iron, chromium, cobalt, aluminum, molybdenum, manganese, tantalum, tungsten, niobium, magnesium, calcium, and alloys containing these materials. Alternatively, synthetic resin materials such as polyethylene (PE), polypropylene (PP), polyolefins, polyamides, polyvinyl chloride, polyphenylene sulfide, polycarbonate, polyethers, and polymethyl methacrylate can also be used. Furthermore, biodegradable resins (biodegradable polymers) such as polylactic acid (PLA), polyhydroxybutyrate (PHB), polyglycolic acid (PGA), and poly-ε-caprolactone can also be used.

[0057] Next, other components of the locking stent 2 will be described. Figure 5 is a view from the inside of the locking stent 2 of the second configuration, virtually unfolded on a plane. The locking stent 2 of the second configuration differs from the locking stent 2 of the first configuration in that at least one cell 20 of the main body 11 has open cell portions 21 and 27. In the locking stent 2 of the second configuration, the other components are the same as those of the locking stent 2 of the first configuration, so some reference numerals are omitted, the same reference numerals are used for equivalent parts, and redundant explanations are omitted.

[0058] As shown in Figure 5, in the second configuration of the locking stent 2, at least one of the cells 20a having an open cell portion 21 has an open cell portion 27. In Figure 5, an example is shown in which the cell 20a having the open cell portion 27 is provided at the distal end of the longitudinal axis LD, but the cell 20a having the open cell portion 27 may be provided at the proximal end of the longitudinal axis LD, or between the distal end and the proximal end. Furthermore, the cell 20a having the open cell portion 27 may be provided along the longitudinal axis LD, along the circumferential direction RD, or spirally along the longitudinal axis LD. In each direction, there may be one or more cells 20a having the open cell portion 27.

[0059] As shown in region A3 of Figure 5, in the second configuration of the locking stent 2, the open cell portion 27 of cell 20a is the portion where one end of two struts 24h and 24i are connected at the top 28, and where no other strut is connected to the top 28. The strut 24h (part of the wire-like member) is formed in a roughly U-shape, roughly J-shape, etc. toward the circumferential direction D4. The strut 24i (part of the wire-like member) is formed in a roughly curved shape. That is, in the open cell portion 27, neither of the two struts 24h and 24i is formed in a roughly straight line. Therefore, the open cell portion 27 as a whole is not roughly V-shaped, but has a shape with two bent portions such as a roughly S-shape, roughly N-shape, or roughly Z-shape.

[0060] In the open cell portion 27, the other ends of the two struts 24h and 24i are connected to the struts of other adjacent cells 20 and / or the closed cell portion 23 in the cell arrangement direction SD. That is, the open cell portion 27 differs from the open cell portion 21 in that the other ends of the struts 24h and 24i are not connected to the struts of the same row and / or the closed cell portion 23 extending in the cell arrangement direction SD. Thus, the open cell portion 27 does not satisfy the structural requirements for the two struts to extend along the longitudinal axis LD when the locking stent 2 is in a reduced diameter state, and therefore, when the locking stent 2 is in a reduced diameter state, the two struts will not extend along the longitudinal axis LD.

[0061] In the open cell portion 27, the shape of the strut 24h is not limited to a substantially U-shape, but may be, for example, a substantially V-shape, a substantially Ω-shape, etc. When the locking stent 2 is in a reduced diameter state, the two struts 24h and 24i of the open cell portion 27 of cell 20a do not substantially extend along the longitudinal axis LD. Also, when the locking stent 2 is in its natural state, the top 28 of the open cell portion 27 of cell 20a protrudes along the circumferential direction RD perpendicular to the longitudinal axis LD. The range of direction in which the top 28 of the open cell portion 27 protrudes along the circumferential direction RD may be, for example, the same as the range of direction in which the top 25 of the open cell portion 21 protrudes relative to the circumferential direction RD (see Figure 4). Furthermore, the top 28 of the open cell portion 27 of the locking stent 2 protrudes substantially along the circumferential direction RD not only in the natural state, but also in the expanded diameter state released from the first catheter 5 in the blood vessel.

[0062] Next, some procedures for delivering a treatment device to a target location TP using the delivery system 10 of this embodiment will be described. Note that various other operations are performed during the procedure, but these will be omitted here. In this embodiment, the biological lumen V is a blood vessel. In particular, the distal stabilizer 1 and delivery system 10 of this embodiment are preferably used when the blood vessel includes highly curved, tortuous vessels. Furthermore, the distal stabilizer 1 and delivery system 10 of this embodiment are preferably used when the target location TP is located in a region with a blood vessel diameter of 7 mm or less, specifically less than 2.5 mm (preferably 2.0 mm or less or 1.5 mm or less). Specifically, the target location TP may be the region of the middle cerebral artery (MCA) from M2 onwards (M2, M3, M4, etc.), the A1, A2 region of the anterior cerebral artery (ACA), the region of the posterior cerebral artery (PCA) from P1 onwards (P1, P2, etc.), the internal carotid artery (ICA), etc. However, the target location (TP) is not limited to these and may be located in a wide range of areas with a vascular inner diameter of 0.5 to 10 mm.

[0063] Figures 6 to 14 are schematic diagrams showing a first example of a procedure using the delivery system 10, which includes the distal stabilizer 1. First, the second catheter 6 is introduced into the proximal D1 of the patient's biological lumen V. Typically, as shown in Figures 6 and 7, the second catheter 6 is difficult to advance distally because its distal end 61 tends to get caught on bends and branches in the biological lumen V. In such cases, as shown in Figure 8, the first catheter 5 is inserted into the biological lumen V and pushed out from the distal end 61 of the second catheter 6, and then the distal end 51 of the first catheter 5 is advanced to the vicinity of the target position TP. Subsequently, as shown in Figure 9, the distal stabilizer 1 is inserted into the first catheter 5 and advanced to the vicinity of the target position TP. At this time, the locking stent 2 (not shown) of the distal stabilizer 1 is housed in the first catheter 5 in a reduced diameter state. As shown in Figure 3A, in the reduced diameter state of the locking stent 2, the two struts 24a and 24b of the open cell portion 21 extend along the long axis LD, similar to the other struts 24. This makes it easier for the thrust force applied by the operator to the delivery wire 3 to be transmitted along the long axis of the locking stent 2, thereby improving the pushability of the locking stent 2. Note that in Figure 9, the distal stabilizer 1 (locking stent 2 + delivery wire 3) is housed throughout the entire first catheter 5, but for convenience, only the distal side of the first catheter 5 is shown with a dashed line representing the distal stabilizer 1.

[0064] Next, as shown in Figure 10, the locking stent 2, which is housed in the first catheter 5 in a reduced diameter state, is released from the distal end 51 of the first catheter 5. The release of the locking stent 2 is performed, for example, by retracting the first catheter 5 towards the proximal end D1. Once released from the distal end 51 of the first catheter 5, the locking stent 2 expands due to its own self-expansion force. As a result, the locking stent 2 pushes against the inner wall V1 of the biological lumen V from the inside out, and is locked to the inner wall V1 by frictional force.

[0065] Next, as shown in Figure 11, the second catheter is extrapolated onto the first catheter 5, and the second catheter 6 is advanced distally to D2 in the biological lumen V. Alternatively, after locking the locking stent 2 to the inner wall V1 of the biological lumen V, the first catheter 5 may be removed, and the second catheter 6 may be advanced distally to D2 in the biological lumen V along the delivery wire 3. The second catheter 6 has a large outer diameter and high rigidity. Therefore, as the second catheter 6 advances, it repeatedly applies a pulling force to the less rigid first catheter 5 and delivery wire 3 proximal to D1. As mentioned above, in conventional locking stents, the force applied to pull the delivery wire proximal to D1 can cause the position of the locking stent 2, which is locked to the inner wall of the biological lumen V, to shift. However, in this embodiment, the locking stent 2 expands in diameter within the blood vessel, causing the top 25 of the open cell portion 21 to protrude along the circumferential direction RD, creating a structural catch. This, combined with the frictional force due to self-expansion, further improves the anchoring force. Therefore, displacement of the locking stent 2 due to repeated application of tensile force can be suppressed. Furthermore, in the procedure of advancing the second catheter 6 along the delivery wire 3, by advancing the second catheter 6 with the delivery wire 3 in contact with the inner wall of the bent portion of the biological lumen, a frictional force is generated at the point where the inner wall and the delivery wire 3 come into contact, further improving the apparent anchoring force of the locking stent 2. Here, the delivery wire 3 is pulled proximal D1 to bring it into contact with the inner wall of the biological lumen.

[0066] In order to perform such a procedure, it is necessary to be able to visually confirm the position and curvature of the delivery wire 3 in the X-ray transmission image. Specifically, the delivery wire 3 has a visibility portion that includes an X-ray opaque portion provided on the distal side of the delivery wire 3 and which can be bent axially together with the delivery wire 3. The visibility portion is provided along the axial direction from the distal end of the linear delivery member toward the proximal end. The axial length of the visibility portion may be 10 to 500 mm. Preferably, the X-ray opaque portion is provided in 10% or more of the surface area of ​​the visibility portion. The X-ray opaque portion may be composed of a tubular member provided on the outer circumferential surface of the delivery wire 3, or it may be composed of a wire-shaped member wrapped around the outer circumferential surface of the delivery wire 3. Furthermore, the X-ray opaque portion may be provided continuously or discontinuously in the axial direction of the visibility portion.

[0067] Examples of X-ray opaque materials include platinum, gold, tantalum, tungsten, iridium, platinum-tungsten, and their alloys. Examples of alloy materials include X-ray opaque polymer materials to which X-ray opaque fillers have been added.

[0068] Furthermore, if it is difficult to advance the second catheter 6, the delivery wire 3 may be pulled proximal D1 while the locking stent 2 is locked to the inner wall V1 of the biological lumen V. This pulling operation allows the second catheter 6 to be advanced distally D2. Specifically, when the delivery wire 3 is pulled proximal D1 while the locking stent 2 is locked to the inner wall V1, the path of the delivery wire 3 within the biological lumen V shortens as it tries to become more linear. At this time, if the proximal D1 portion of the second catheter 6 is held directly or indirectly, the position of the proximal D1 portion of the second catheter 6 does not change, and instead, as shown in Figure 11, the distal end 61 of the second catheter 6 advances within the biological lumen V. Also, if the position of the proximal D1 portion of the second catheter 6 does not change and the distal end 61 of the second catheter 6 advances within the biological lumen V, the path of the second catheter 6 approaches a linear shape. This procedure is particularly useful when attempting to pass the second catheter 6 through areas that are difficult to access, such as areas with sharp bends or small inner diameters in the biological lumen V. The distal stabilizer 1 of this embodiment can suppress displacement of the locking stent 2, which is locked to the inner wall V1 of the biological lumen V, even when such a procedure is performed.

[0069] Furthermore, when locking the locking stent 2 distal to the aneurysm and delivering a target catheter with a large outer diameter to the vicinity of the aneurysm, the first catheter 5, which is inserted into the target catheter (second catheter 6) during its advancement, may become lost in the aneurysm (not shown) along with the delivery wire 3. In such cases, by pulling the delivery wire 3 proximal D1 while the locking stent 2 is locked distal to the aneurysm, the path of the delivery wire 3 within the biological lumen V is shortened, allowing the delivery wire 3 and the first catheter 5 to be returned from the aneurysm to the biological lumen V. As described above, the distal stabilizer 1 of this embodiment can suppress displacement of the locking stent 2 locked within the biological lumen V even when returning a wire or catheter lost in the aneurysm back into the biological lumen V. Therefore, it can be suitably used for delivering the target catheter to the vicinity of the target position while the locking stent 2 is locked distal to the aneurysm.

[0070] After the delivery of the second catheter 6 is completed in this manner, as shown in Figure 12, the distal stabilizer 1 is retracted to the proximal D1 and the locking stent 2 is re-sheathed (stored) in the first catheter 5 (not shown). With the distal stabilizer 1 of this embodiment, even when re-sheathing the locking stent 2, displacement of the locking stent 2, which is locked to the inner wall V1 of the biological lumen V, can be suppressed during re-sheathing. After re-sheathing the distal stabilizer 1 in the first catheter 5, the first catheter 5 and the distal stabilizer 1 may be withdrawn from the proximal D1 of the second catheter 6. Alternatively, after withdrawing the first catheter 5 from the proximal D1, the distal stabilizer 1 may be re-sheathed in the second catheter 6 and withdrawn from the proximal D1. In the locking stent 2 of this embodiment, the direction in which the top 26 of the open cell portion 22 protrudes is generally along the longitudinal axis LD, which facilitates resheathing of the first catheter 5 and the second catheter 6.

[0071] Next, as shown in Figure 13, the second catheter 6 is positioned at the target location TP in the biological lumen V. This allows the treatment device 7 inserted into the second catheter 6 to be easily delivered to the target location TP, as shown in Figure 14. Alternatively, the second catheter 6 or the third catheter itself may be used as the treatment device. For example, when the second catheter 6 is used as a thrombus aspiration device, the thrombus at the target location TP is aspirated and removed from the distal end 61 by creating negative pressure in the internal flow path of the second catheter 6. Note that the removal of the distal stabilizer 1 is not limited to before the delivery of the treatment device 7, but may also be done afterward. In the latter case, the second catheter 6 has a dual or dual structure, with a lumen through which the distal stabilizer 1 and the first catheter 5 are inserted, and a lumen through which the treatment device 7 is inserted.

[0072] The treatment device 7 is, for example, a thrombus aspiration device, a flow diverter, an embolization coil, an aneurysm embolization device, a thrombectomy device (such as a stent retriever), a stent for treating an aneurysm, a stent for treating intracranial artery stenosis, a balloon catheter, a shunt, or a means for releasing liquid embolizing material (such as a catheter equipped with a lumen for passing liquid embolizing material). According to the distal stabilizer 1 of this embodiment, these treatment devices can be delivered transcatheterally to the area of ​​the blood vessel with an inner diameter of 0.5 mm to 10 mm, preferably 7 mm or less, specifically less than 2.5 mm (preferably 2.0 mm or less, or 1.5 mm or less), and diseases or conditions (such as vascular occlusion and aneurysms) in these areas can be treated or improved with minimal burden on the patient.

[0073] The therapeutic device 7 delivered to the target position TP may be used within the biological lumen (e.g., thrombus aspiration device, flow diverter, aneurysm embolization device, thrombectomy device, stent for aneurysm treatment, stent for intracranial artery stenosis treatment, balloon catheter, or liquid embolic material release means), or it may be used protruding outside the biological lumen (e.g., shunt). The distal stabilizer 1 of this embodiment is also applicable to a method in which the therapeutic device 7 is delivered to the target position TP in the biological lumen V by the delivery system 10, and the therapeutic device 7 is used to perform a therapeutic procedure by protruding from the target position TP within the biological lumen V or from the target position TP outside the biological lumen V.

[0074] Next, a second example of the procedure using the delivery system 10, including the distal stabilizer 1, will be described using Figures 15 to 22. In the second example of the procedure, the steps up to delivering the first catheter 5 towards the target position TP are substantially the same as in the first example of the procedure. Therefore, in the second example of the procedure, the explanation will begin from the stage of delivering the first catheter 5 to the target position TP, and the explanation of the preceding steps will be omitted. Figures 15 to 22 are schematic diagrams showing the second example of the procedure using the delivery system 10, including the distal stabilizer 1.

[0075] The second example of the procedure describes the treatment of an aneurysm formed at the target point (TP) within the biological lumen V. Therefore, in Figures 15 to 22, the shape of the target point (TP) and the distal vessel differ from that in the first example of the procedure. In this example, the aneurysm at the target point (TP) is, for example, an aneurysm formed distal to narrow, tortuous vessels such as the anterior cerebral artery (ACA), anterior communicating artery (Acom), and middle cerebral artery (MCA) within the skull. The distal side of the internal carotid artery (ICA) has many tortuous vessels. Therefore, as shown in the second example of the procedure, when treating an aneurysm formed in the middle cerebral artery (MCA), which is distal to the internal carotid artery, it is important to make contact with more bends in the delivery wire 3 on the distal side of the internal carotid artery.

[0076] As shown in Figure 15, the first catheter 5 is inserted into the second catheter 6 and advanced into the biological lumen V. After pushing the first catheter 5 out from the distal end 61 of the second catheter 6, the distal end 51 of the first catheter 5 is advanced distal to the target position TP. In the second example of the procedure, the distal side of the target position TP branches into two biological lumen Va and Vb at the bifurcation point BP. Figure 15 shows an example in which the distal end 51 of the first catheter 5 is advanced toward the biological lumen Va, which has a greater bend. "Greater bend" means that among the multiple branched biological lumen, it has the greatest bend relative to the other biological lumen. Subsequently, as shown in Figure 16, the distal stabilizer 1 is inserted into the first catheter 5 and advanced toward the distal side of the target position TP (biological lumen Va).

[0077] Next, as shown in Figure 17, the locking stent 2, which is housed in the first catheter 5 in a reduced diameter state, is released from the distal end 51 of the first catheter 5. Once released from the distal end 51 of the first catheter 5, the locking stent 2 expands due to its self-expanding force. As a result, the locking stent 2 is locked to the inner wall of the biological lumen Va, which has greater curvature at the bifurcation site BP (first step). The locking stent 2 is also locked to a position where there is one or more bends between the target position TP and the position where the locking stent 2 is locked. In this example, the locking stent 2 is locked to a position where there are two bends in the biological lumen V between the target position TP and the position where the locking stent 2 is locked. Between the target position TP and the position where the locking stent 2 is locked, the upper limit of bends is three, for example, in the case of the middle cerebral artery, if the vessel diameter at the bend is 1.0 to 3.0 mm. In the case of the anterior cerebral artery, if the diameter of the vessel at the bend is between 1.0 and 3.0 mm, there are four arteries.

[0078] In this way, by securing the locking stent 2 as distal as possible to the delivery point of the second catheter 6, the exposed portion of the delivery wire 3 can be made longer distal to the target position TP. This increases the contact area between the delivery wire 3 and the bent portion of the biological lumen, thereby improving the anchoring force of the locking stent 2. Depending on the location of the biological lumen, the exposed portion of the delivery wire 3 should preferably be 10 mm or more, more preferably 20 mm or more, and if it is 50 mm or more, it can contact the bent portion in most biological lumens. If the exposed portion of the delivery wire 3 is 100 mm or more, it can contact the bent portion at any point in the biological lumen. The appropriate upper limit for the exposed portion of the delivery wire 30 is, for example, about 70 mm for the middle cerebral artery and about 50 mm for the anterior cerebral artery.

[0079] Furthermore, the locking stent 2 is locked distal to the target position TP, with the exposed portion of the delivery wire 3 spanning one or more bends or branches of the biological lumen V. In this example, the locking stent 2 is locked distal to the target position TP, with the exposed portion of the delivery wire 3 spanning one bend and one branch of the biological lumen V. Not limited to this example, the locking stent 2 may also be locked distal to the target position TP, with the exposed portion of the delivery wire 3 spanning one or more bends of the biological lumen V, or with the exposed portion of the delivery wire 3 spanning one or more branches of the biological lumen V. The upper limit of the number of bends of the biological lumen V that the exposed portion of the delivery wire 3 spans is, for example, XX. Also, the upper limit of the number of branches of the biological lumen V that the exposed portion of the delivery wire 3 spans is, for example, 3 in the case of the middle cerebral artery, if the vessel diameter at the bend is 1.0 to 3.0 mm. In the case of the anterior cerebral artery, if the diameter of the vessel at the bend is between 1.0 and 3.0 mm, there are four arteries.

[0080] Next, as shown in Figure 18, the first catheter 5 (not shown) is withdrawn to the proximal D1 and then removed, exposing the delivery wire 3 in the biological lumen V (second step). Alternatively, the first catheter 5 may be retracted to the vicinity of the distal end 61 of the second catheter 6 without being withdrawn from the second catheter 6. As will be described later, the first catheter 5 may or may not be removed as long as the exposed portion of the delivery wire 3 can be brought into contact with one or more bends in the biological lumen V.

[0081] Next, as shown in Figure 19, the delivery wire 3 is pulled in proximal D1 and brought into contact with the bent portion in the biological lumen V. In this example, by pulling the delivery wire 3 in proximal D1, the exposed portion of the delivery wire 3 comes into contact with three bent portions in the biological lumen V. Note that it is sufficient for the exposed portion of the delivery wire 3 to be in contact with one or more bent portions in the biological lumen V.

[0082] Next, as shown in Figure 20, the second catheter 6 is advanced distally to D2 with the delivery wire 3 extrapolated and positioned at the target position TP (third step). At least at the start of this third step, the exposed portion of the delivery wire 3 is in contact with one or more bends in the biological lumen V, while the second catheter 6 is advanced distally to D2 with the delivery wire 3 extrapolated. The locking stent 2 is firmly locked to the inner wall of distal D2 at the target position TP. Furthermore, as will be described later, the second catheter 6 can be advanced distally to D2 with the delivery wire 3 in contact with one or more bends in the biological lumen V. This increases the frictional force of the entire distal stabilizer 1 against the biological lumen V. Therefore, the entire distal stabilizer 1 can be more securely retained within the biological lumen V, counteracting the force that pulls the delivery wire 3 proximal when the second catheter 6 is advanced.

[0083] Furthermore, according to the distal stabilizer 1 of this embodiment, it is possible to reduce the self-expansion force of the locking stent 2 without significantly reducing the frictional force of the distal stabilizer 1 against the biological lumen V, thereby further reducing the burden on the blood vessel wall.

[0084] After the distal end 61 of the second catheter 6 reaches the target position TP in the biological lumen V, the second catheter 6 is further advanced distally to D2, and the locking stent 2 is re-sheathed onto the second catheter 6 (fourth step).

[0085] Next, although not shown in the diagram, a reduced-diameter stent 4 is inserted from the proximal D1 of the second catheter 6. The stent 4 is a stent (treatment device) for treating aneurysms. Then, as shown in Figure 22, the stent 4 is advanced distally towards D2 via the pusher wire 8, pushed out from the second catheter 6 at the target position TP, and delivered to the target position TP (5th step). The purpose of placing the stent 4 at the target position TP is to reduce the blood flow into the aneurysm AR located at the target position TP and to hold the embolic coil to be placed in the aneurysm AR. After placing the stent 4 at the target position TP, the embolic coil (not shown) is advanced distally towards D2 via a microcatheter inserted into the second catheter 6, allowing the embolic coil to be placed in the aneurysm AR through the mesh of the stent 4 (6th step). Furthermore, when the implanted stent 4 self-expands, the pusher wire 8 that was trapped in the implanted stent 4 becomes detached, allowing the pusher wire 8 to be retrieved while the implanted stent 4 remains in the bulge.

[0086] In a second example of a procedure in which the second catheter 6 is advanced along the delivery wire 3, the second catheter 6 can be advanced distally D2 while the delivery wire 3 is in contact with the inner wall of one or more bent sections in the biological lumen V. That is, as shown in Figure 19, when the second catheter 6 is advanced distally D2, the delivery wire 3 is in contact with one or more bent sections distal to the target position TP at D2. In addition, the delivery wire 3 is in contact with one or more bent sections proximal to the target position TP at D1. As a result, the frictional force generated by the contact between the delivery wire 3 and the inner wall of the biological lumen V is increased, and the frictional force of the distal stabilizer 1 against the biological lumen V can be further improved. Therefore, with the distal stabilizer 1 of this embodiment, the distal stabilizer 1 can be more securely fixed in the locking position against the force that pulls the delivery wire 3 proximal when the second catheter 6 is advanced.

[0087] At the branching point BP in the biological lumen V, the locking stent 2 is locked to the inner wall of the biological lumen Va, which has a greater bend. This increases the frictional force generated by the contact between the delivery wire 3 and the inner wall of the biological lumen Va, thereby improving the anchoring force of the distal stabilizer 1. Furthermore, as the second catheter 6 is advanced distally to D2, the exposed portion of the delivery wire 3 is inserted into the second catheter 6. Therefore, the number of points where the bends and the delivery wire 3 come into contact decreases as the second catheter 6 is advanced distally to D2. However, in the second example of the procedure, the delivery wire 3 maintains contact with one or more bends distal to the target position TP at D2. As a result, the anchoring force of the locking stent 2 can be maintained even when the second catheter 6 is advanced distally to D2, allowing the second catheter 6 to be advanced stably until its distal end 61 is positioned at the target position TP in the biological lumen V.

[0088] The distal stabilizer 1 of this embodiment described above provides, for example, the following effects.

[0089] In the first configuration of the locking stent 2, the open cell portion 21 provided in cell 20a extends along the longitudinal axis LD when the locking stent 2 is in a reduced diameter state, with two struts. This makes it easier for the thrust force applied by the operator to the delivery wire 3 to be transmitted along the longitudinal axis of the locking stent 2, thereby improving the pushability of the locking stent 2. Furthermore, in the main body portion 11 of the locking stent 2, the open cell portion 21 provided in cell 20a protrudes along the circumferential direction RD perpendicular to the longitudinal axis LD when the locking stent 2 is in an expanded diameter state, with the top portion 25 protruding. As a result, the top portion 25 of the open cell portion 21 of the locking stent 2 becomes a structural catch on the inner wall of the blood vessel, and the anchoring force can be further improved through a synergistic effect with the frictional force due to self-expansion.

[0090] In the first configuration of the locking stent 2, the top 25 of the open cell portion 21 provided in the cell 20a protrudes in a direction of +30° to -30° with respect to the circumferential direction RD of the locking stent 2 when the locking stent 2 is in an expanded diameter state. This allows the top 25 of the open cell portion 21 to protrude in a direction that provides sufficient structural engagement when the locking stent 2 is in an expanded diameter state.

[0091] In the first configuration of the locking stent 2, the open cell portion 21 is provided in at least one cell located at the distal end of the main body portion 11 in the longitudinal direction LD. This allows the anchoring force of the locking stent 2 to be maintained until just before the locking stent 2 is re-sheathed into the catheter (first catheter 5).

[0092] In the first configuration of the locking stent 2, the open cell portion 21 is provided in at least one cell located at the proximal end of the main body portion 11 in the longitudinal direction LD. This improves the ability to push the stent into place at the proximal end of the main body portion 11, where the cell density tends to be sparser.

[0093] In the first configuration of the locking stent 2, the open cell portion 21 is provided in at least one cell located between the distal end and the proximal end of the longitudinal axis LD of the main body portion 11. This reduces the number of struts in the area where cells are densely arranged in the main body portion 11 and resistance tends to be high during re-sheathing, and the amount of metal in that area can be made relatively smaller than in other areas, thereby reducing resistance during re-sheathing.

[0094] In the first configuration of the locking stent 2, the open cell portion 21 is also provided in the antenna portion 12. This makes it easier for the thrust force applied by the operator to the delivery wire 3 to be transmitted to the main body portion 11 in the antenna portion 12 where the cell density is sparser, thereby improving the pushability of the locking stent 2.

[0095] In the first configuration of the locking stent 2, at least one of the cells having an open cell portion 21 has an open cell portion 22 in which, in the reduced diameter state and the natural state, the two struts do not substantially extend along the longitudinal axis LD. By making the top 26 of this open cell portion 22 protrude distally D2 along the longitudinal axis LD, resheathing to the first catheter 5 and the second catheter 6 is facilitated.

[0096] In the second configuration of the locking stent 2A, at least one of the cells 20a having an open cell portion 21 has an open cell portion 27. In the expanded state, the strut 24h (part of the wire-like member) of the open cell portion 27 protrudes along the circumferential direction RD. As a result, the top portion 28 of the open cell portion 27, in the expanded state, becomes a structural catch on the inner wall of the blood vessel, and the anchoring force can be further improved through a synergistic effect with the frictional force due to the self-expansion force. In particular, by positioning the cell having the open cell portion 27 distally, the anchoring force of the locking stent 2 can be exerted until just before the locking stent 2 is re-sheathed by the catheter (first catheter 5).

[0097] In the first and second configurations of the locking stent, the main body 11 has a mesh pattern structure in which multiple cells 20 are arranged spirally with respect to the longitudinal axis LD. Therefore, the distal stabilizer 1 having the locking stent is highly flexible and can easily follow the curvature of the biological lumen V. In this way, because the distal stabilizer 1 can easily follow the curvature of the biological lumen V, stress is less likely to concentrate at both ends of the longitudinal axis LD of the locking stent. As a result, the blood vessel to which the locking stent is locked is less likely to straighten, resulting in an open-cell structure that is highly protective of the blood vessel wall.

[0098] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications and changes are possible, as shown in the modified forms described later, and these are also included within the technical scope of the present invention. Furthermore, the effects described in the embodiments are merely a list of the most preferred effects resulting from the present invention and are not limited to those described in the embodiments. The embodiments described above and the modified forms described later can be used in combination as appropriate, but a detailed explanation is omitted. (Transformed form)

[0099] In the locking stent 2, at least one cell 20a having open cell portions 21 and 22 is provided in the main body portion 11, and the other cells 20 may, for example, have only the open cell portion 21 or 22, or may not have the open cell portions 21 and 22.

[0100] In the open cell portion 21 of cell 20a, the other ends of struts 24a and 24b may be connected by another strut in the cell arrangement direction SD. With this configuration, when the locking stent 2 is in a reduced diameter state, the two struts do not extend along the longitudinal axis direction LD, but when the locking stent 2 is in its natural state (and expanded diameter state), the top portion 25 protrudes along the circumferential direction RD. Therefore, an improvement in anchoring force in the expanded diameter state can be expected.

[0101] In the open cell portion 27 of cell 20a, the other ends of the two struts 24h and 24i are connected to the struts of other adjacent cells 20 or to the closed cell portion 23 in the cell arrangement direction SD (see Figure 5). In this configuration, by making the shape of the open cell portion 27 roughly L-shaped and appropriately setting the angle of the apex, the two struts can be extended along the longitudinal axis LD when the locking stent 2 is in a reduced diameter state.

[0102] In the locking stent 2, the mesh pattern structure in which the cells 20 are arranged along the longitudinal axis is not limited to a structure in which the cells 20 are arranged spirally with respect to the longitudinal axis LD, as shown in the embodiment. For example, it may be a mesh pattern structure in which the cells 20 are arranged along the longitudinal axis LD and also in the circumferential direction RD, or it may be a mesh pattern structure in which the cells 20 are arranged only along the longitudinal axis LD. In other words, the locking stent 2 only needs to have a mesh pattern structure in which the cells 20 are arranged at least along the longitudinal axis LD.

[0103] The locking stent 2 is used for temporary placement in a blood vessel and then retrieval from the body, but it can also be used in applications where the locking stent 2 is left in the blood vessel without being retrieved from the body. In such applications, for example, the connection between the locking stent 2 and the delivery wire 3 may be constructed using a heater coil, filament, etc., so that the connection is cut (melted) when current is passed through the delivery wire 3. Alternatively, the connection between the locking stent 2 and the delivery wire 3 may be mechanically cut when a rotational force is applied to the delivery wire 3 in the circumferential direction. The connection between the locking stent 2 and the delivery wire 3 is not limited to the above examples; any configuration is acceptable as long as the locking stent 2 and the delivery wire 3 can be separated by the operator's manipulation. [Explanation of Symbols]

[0104] 1. Distal stabilizer 2. Locking stent 3 Delivery wire 4. Indwelling stent 5. First catheter 6. Second catheter 10 Delivery System 11 Main body 12 Antenna section Cells 20, 20a, 20b 21(21a,21b),22,27 Open cell portion 23 Close cell section 24 (24a~24i) Strut 25,26,28 top

Claims

1. A distal stabilizer used for catheter delivery in a biological lumen, Linear delivery member and It comprises a cylindrical portion connected to the linear delivery member and locked to the inner wall of a biological lumen, The cylindrical portion comprises a main body having a mesh pattern structure in which cells, surrounded by wire-like members, are arranged at least along the long axis, At least one of the cells forming the main body has at least one open cell portion in which two wire-like members are connected at the top, and in the reduced diameter state, the two wire-like members extend along the longitudinal axis, and in the natural state, the top protrudes along the circumferential direction perpendicular to the longitudinal axis. Distal stabilizer.

2. In its natural state, the open cell portion has its top protruding in a direction of +30° to -30° relative to the circumferential direction of the cylindrical portion. The distal stabilizer according to claim 1.

3. The open cell portion is provided in at least one of the cells located at the distal end in the longitudinal direction of the main body, The distal stabilizer according to claim 1 or 2.

4. The open cell portion is provided in at least one of the cells located at the proximal end in the longitudinal direction of the main body, The distal stabilizer according to claim 1 or 2.

5. The open cell portion is provided in at least one of the cells located between the distal end and the proximal end in the longitudinal direction of the main body. The distal stabilizer according to claim 1 or 2.

6. The open cell portion is also provided in the antenna portion that connects the proximal end of the main body to the linear delivery member. The distal stabilizer according to claim 1 or 2.

7. At least one of the cells having the open cell portion has an open cell portion in which, in the reduced diameter state, a portion of the wire-like member does not substantially extend along the longitudinal axis direction, and in the natural state, a portion of the wire-like member protrudes along the circumferential direction perpendicular to the longitudinal axis direction. The distal stabilizer according to claim 1 or 2.

8. At least one of the cells having the open cell portion has an open cell portion in which, in the reduced diameter state and the natural state, a portion of the wire-like member does not substantially extend along the longitudinal axis. The distal stabilizer according to claim 1 or 2.

9. The cylindrical portion has a structure in which the cells are arranged spirally with respect to the long axis. The distal stabilizer according to claim 1 or 2.

10. The distal stabilizer is used for applications where it is temporarily placed in a biological lumen and then retrieved from the body. The distal stabilizer according to claim 1 or 2.

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