stent

Abstract

This invention provides a stent that can be better positioned within a bifurcated biological lumen. [Solution] The stent 100 has a main pipe 10, a first branch pipe 20 and a second branch pipe 30, and the main pipe 10, the first branch pipe 20 and the second branch pipe 30 each have a first tubular body 41, a second tubular body 42 and a third tubular body 43 which are made up of a mesh structure formed by weaving wires, and the mesh structure has a plurality of zigzags that extend in the circumferential direction of the tubular body 40 while swinging in a zigzag pattern in the axial direction at each stage 52 Including the extended portion 50, each zigzag extended portion 50, after swinging in a zigzag pattern, loops with the zigzag extended portion 50 of the adjacent step 52 to form a mutual loop portion 60, and the depth of the loop between the zigzag extended portion 50 of the second tubular body 42 and the zigzag extended portion 50 of the third tubular body 43 is deeper than the depth of the loop between the zigzag extended portion 50 of the first tubular body 41 and the zigzag extended portion 50 of the second tubular body 42.

Description

Technical Field

[0001] The present invention relates to a stent.

Background Art

[0002] As a stent having a diagonal lattice structure composed of wires, for example, there is one described in Patent Document 1. Patent Document 1 describes a stent having a structure branched in a Y shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the study of the inventor of the present application, the stent of Patent Document 1 still has room for improvement from the viewpoint of being satisfactorily placed in a bifurcated biological lumen.

Means for Solving the Problems

[0005] According to the present invention, there is provided a stent having a main tube, a first branch tube and a second branch tube respectively branched from a stent branch portion which is one end of the main tube, the main tube, the first branch tube and the second branch tube each have a tubular body having a mesh structure formed by braiding wires, the mesh structure includes a plurality of stages arranged at positions shifted from each other in the axial direction of the tubular body, the wires each include a plurality of zigzag extending portions extending in the circumferential direction of the tubular body while zigzagging in the axial direction at each stage, each zigzag extending portion is continuous with a zigzag extending portion of an adjacent stage at the tip extending in the circumferential direction, and each zigzag extending portion loops with a zigzag extending portion of an adjacent stage at the zigzagged tip to form an interlocking loop portion. The zigzag extension at one end of the first tubular body, which constitutes the main pipe, loops with the zigzag extension at one end of the second tubular body, which constitutes the first branch pipe, forming a mutual loop section, and also loops with the zigzag extension at one end of the third tubular body, which constitutes the second branch pipe, forming a mutual loop section. The zigzag extension at one end of the second tubular body loops with the zigzag extension at one end of the third tubular body to form a mutual loop portion. The axial direction of the first tubular body is defined as the first axial direction, The axial direction of the second tubular body is defined as the second axial direction, The axial direction of the third tubular body is defined as the third axial direction, The plane containing the first axis direction and the second axis direction is defined as the first plane. The plane containing the second axis direction and the third axis direction is defined as the second plane. In the first plane, the angle bisector of the angle between the first axis direction and the second axis direction is defined as the first bisector. If the angle bisector of the angle between the second axis direction and the third axis direction in the second plane is defined as the second bisector, When viewing the mutual loop portion at the intersection of the first tubular body and the second tubular body in a direction parallel to the first bisector, the depth of the loop between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body is greater than the depth of the loop between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body. When viewing the mutual loop portion at the intersection of the second tubular body and the third tubular body in a direction parallel to the second bisector, the depth of the loop between the zigzag extension portion of the second tubular body and the zigzag extension portion of the third tubular body is greater than the depth of the zigzag extension portion of the third tubular body. A deep stent is provided. [Effects of the Invention]

[0006] According to the present invention, the stent can be placed more effectively within a bifurcated biological lumen. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic plan view of the stent according to the embodiment. [Figure 2] This is a schematic exploded plan view of the stent according to the embodiment. [Figure 3] This is a schematic exploded plan view of the stent according to the embodiment, showing the state before both ends of the wires of the first tubular body and the second tubular body are fixed. [Figure 4] This is a schematic plan view of the stent according to the embodiment, showing the stent as a whole deformed into a roughly I-shape. [Figure 5] This is a partially enlarged view of one end of the main pipe in the embodiment. [Figure 6] Figure 6(a) is a diagram showing the boundary between the main pipe and the first branch pipe and the surrounding structure in the embodiment, and is shown as viewed in the direction of arrow A shown in Figure 1. Figure 6(b) is a partial enlarged view of section A shown in Figure 6(a). [Figure 7] Figure 7(a) is a diagram showing the boundary between the main pipe and the second branch pipe and the surrounding structure in the embodiment, and is shown as viewed in the direction of arrow B shown in Figure 1. Figure 7(b) is a partial enlarged view of section A shown in Figure 7(a). [Figure 8] Figure 8(a) shows the boundary between the first branch pipe and the second branch pipe and the surrounding structure in the embodiment, as viewed in the direction of arrow C shown in Figure 1, and Figure 8(b) is a partial enlarged view of section A shown in Figure 8(a). [Figure 9] Figure 9(a) is a diagram showing the boundary between the main pipe and the first branch pipe and the surrounding structure in the embodiment, and is shown as viewed in the direction of arrow A shown in Figure 4. Figure 9(b) is a partial enlarged view of section A shown in Figure 9(a). [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to Figures 1 to 9(b). In all drawings, similar components are denoted by the same reference numeral, and explanations are omitted where appropriate. Figures 1 to 5, 6(a), 7(a), 8(a), and 9(a) show simplified and schematic representations of the shapes of the multiple zigzag extensions 50.

[0009] As shown in Figure 1, the stent 100 has a main pipe 10 and a first branch pipe 20 and a second branch pipe 30 that branch off from a stent branch section 15, which is one end of the main pipe 10. The main pipe 10, the first branch pipe 20, and the second branch pipe 30 each have a tubular body 40 with a mesh structure 40a formed by weaving wires. As shown in Figure 5, the mesh structure 40a includes a plurality of steps 52 positioned offset from each other in the axial direction of the tubular body 40, and each wire includes a plurality of zigzag extensions 50 that extend in the circumferential direction of the tubular body 40 while swinging in a zigzag pattern in the axial direction at each step 52, and each zigzag extension 50 is connected to a zigzag extension 50 of the adjacent step 52 at the end of its circumferential extension, and each zigzag extension 50 loops with the zigzag extension 50 of the adjacent step 52 at the end of its zigzag swing to form a mutual loop section 60. More specifically, the zigzag extension 50 at one end 41a of the first tubular body 41, which constitutes the main pipe 10, loops with the zigzag extension 50 at one end 42a of the second tubular body 42, which constitutes the first branch pipe 20, to form a mutual loop section (hereinafter, the first mutual loop section 62). It also loops with the zigzag extension 50 at one end 43a of the third tubular body 43, which constitutes the second branch pipe 30, to form a mutual loop section (hereinafter, the third mutual loop section 66). Furthermore, the zigzag extension 50 at one end 42a of the second tubular body 42 loops with the zigzag extension 50 at one end 43a of the third tubular body 43, to form a mutual loop section (hereinafter, the second mutual loop section 64). Here, the axial direction of the first tubular body 41 is taken as the first axial direction, the axial direction of the second tubular body 42 is taken as the second axial direction, the axial direction of the third tubular body 43 is taken as the third axial direction, the plane including the first axial direction and the second axial direction is taken as the first plane 110 (see FIG. 6(a)), and the plane including the second axial direction and the third axial direction is taken as the second plane 120 (see FIG. 8(a)). Further, the angle bisector of the angle formed by the first axial direction and the second axial direction in the first plane 110 is taken as the first angle bisector 206, and the angle bisector of the angle formed by the second axial direction and the third axial direction in the second plane 120 is taken as the second angle bisector 207. When viewing the mutual loop portion (the first mutual loop portion 62) of the intersection portion 45 between the first tubular body 41 and the second tubular body 42 in the direction parallel to the first angle bisector 206 (the direction of arrow A shown in FIG. 1), the depth of the loop of the zigzag extending portion 50 of the first tubular body 41 and the zigzag extending portion 50 of the second tubular body 42 (dimension L1 shown in FIG. 6(b)) is smaller than the depth of the loop of the zigzag extending portion 50 of the second tubular body 42 and the zigzag extending portion 50 of the third tubular body 43 (dimension L3 shown in FIG. 8(b)) when viewing the mutual loop portion (the second mutual loop portion 64) of the intersection portion 46 between the second tubular body 42 and the third tubular body 43 in the direction parallel to the second angle bisector 207 (the direction of arrow C shown in FIG. 1). [[ID=*4]]In FIG. 1, the axis of the first tubular body 41 is indicated by a virtual line 201, the axis of the second tubular body 42 is indicated by a virtual line 202, and the axis of the third tubular body 43 is indicated by a virtual line 203. The first axial direction of the first tubular body 41 is the extending direction of the virtual line 201, the second axial direction of the second tubular body 42 is the extending direction of the virtual line 202, and the third axial direction of the third tubular body 43 is the extending direction of the virtual line 203. Also, the "depth of the loop of the zigzag extending portion 50 of the first tubular body 41 and the zigzag extending portion 50 of the second tubular body 42" as referred to here is the maximum opening width of the first mutual loop portion 62, and is the maximum separation distance between the wire of the first tubular body 41 and the wire of the second tubular body 42 that constitute the first mutual loop portion 62. More specifically, in the case of this embodiment, it is the maximum separation distance between the peak portion 57 and the valley portion 58 (to be described in detail later) that constitute the first mutual loop portion 62. [[ID=*7]]<000009*0> Note: There seems to be a formatting issue with the number in tag in the original text. It's translated as <000009*0> here to show the potential problem. You may want to correct it in the original text for a proper translation. Also, the numbering in ID=4 and ID=7 seems a bit off compared to the rest of the sequence. You might need to review and correct those as well for a more consistent presentation.Similarly, the "depth of the loop between the zigzag extension 50 of the second tubular body 42 and the zigzag extension 50 of the third tubular body 43" as referred to herein is the maximum opening width of the second mutual loop portion 64 and is the maximum separation distance between the wire of the second tubular body 42 and the wire of the third tubular body 43 that constitute the second mutual loop portion64. More specifically, in the case of the present embodiment, it is the maximum separation distance between the trough portions 58 (details will be described later) that constitute the second mutual loop portion 64. In the present invention, the "one end 41a of the first tubular body 41" is one end in the first axial direction of the first tubular body 41 alone as shown in FIG. 2. Similarly, the "one end 42a of the second tubular body 42" is one end in the second axial direction of the second tubular body 42 alone as shown in FIG. 2, and the "one end 43a of the third tubular body 43" is one end in the third axial direction of the third tubular body 43 alone as shown in FIG. 2. Note that FIG. 2 shows an excerpt of the first tubular body 41, the second tubular body 42, and the third tubular body 43, and shows them disassembled from each other.

[0010] The stent 100 is placed in the biological lumen using a stent placement device (not shown). The stent 100 is in a reduced diameter state while being accommodated in an outer sheath (not shown) of the stent placement device. When the distal end portion of the outer sheath accommodating the stent 100 is delivered to the placement location of the biological lumen and the stent 100 is detached from the outer sheath, the stent 100 elastically restores from the reduced diameter state to the expanded diameter state. Thus, the stent 100 can be transported and placed at the placement location of the biological lumen. More specifically, as described above, the stent 100 is a Y-shaped stent having a main tube 10 and a first branch tube 20 and a second branch tube 30 that branch from a stent branch portion 15 which is one end of the main tube 10, respectively. The outer sheath of the stent placement device is a single tubular body. While housed in the outer sheath, the first branch pipe 20 bends relative to the main pipe 10 so that its second axial direction extends parallel to the first axial direction, and the second branch pipe 30 bends relative to the main pipe 10 so that its third axial direction extends parallel to the first axial direction. In this way, while housed in the outer sheath, the entire stent 100 is deformed into a roughly I-shape (see Figure 4), and further elongates axially, becoming reduced in diameter. When the stent 100 is placed, the first branch duct 20 and the second branch duct 30 are respectively placed in the bifurcated biological lumen (for example, the left hepatic duct and the right hepatic duct). The first branch duct 20 and the second branch duct 30 are bent relative to the main duct 10 in a direction that brings them closer together or away from each other, in accordance with the angle formed between the bifurcated biological lumen (same as above). The contracted state of stent 100 refers to a state in which stent 100 is compressed radially to the extent that it can exist within the outer sheath. The expanded state of stent 100 refers to a state in which it is at least larger than the contracted state, for example, the natural state of stent 100. In Figures 1 to 9(b), stent 100 is shown in the expanded state (natural state). Furthermore, the loop depth L1 between the zigzag extension 50 of the first tubular body 41 and the zigzag extension 50 of the second tubular body 42, and the loop depth L3 between the zigzag extension 50 of the second tubular body 42 and the zigzag extension 50 of the third tubular body 43, are the loop depths of the stent 100 in its natural state. Furthermore, in this embodiment, the left branch pipe in Figure 1 is designated as the first branch pipe 20, and the right branch pipe is designated as the second branch pipe 30. However, the present invention is not limited to this example, and the left branch pipe may be designated as the second branch pipe 30, and the right branch pipe may be designated as the first branch pipe 20.

[0011] With this configuration, the depth of the loop in the mutual loop section 60 (second mutual loop section 64) at the intersection 46 between the second tubular body 42 and the third tubular body 43 is greater than the depth of the loop in the mutual loop section 60 (first mutual loop section 62) at the intersection 45 between the first tubular body 41 and the second tubular body 42. This makes it possible to realize a stent 100 with a structure that allows for bending in the direction that the angle between the second tubular body 42 and the third tubular body 43 (angle R1 shown in Figure 1) opens up (away from each other). Therefore, even if the angle between the bifurcated biological lumens is greater than the angle R1 between the second tubular body 42 and the third tubular body 43 in the natural state of the stent 100, when the stent 100 is placed, the second tubular body 42 and the third tubular body 43 can bend well away from each other while suppressing deformation of their mesh structure 40a. Therefore, the stent 100 can be placed more effectively within the bifurcated biological lumen.

[0012] In this embodiment, the depth L3 of the loop between the zigzag extension 50 of the second tubular body 42 and the zigzag extension 50 of the third tubular body 43 is preferably 1.1 to 5 times the depth L1 of the loop between the zigzag extension 50 of the first tubular body 41 and the zigzag extension 50 of the second tubular body 42, more preferably 1.2 to 4 times the depth L3, and even more preferably 1.3 to 3.7 times the depth L3.

[0013] Furthermore, the plane containing the first axis direction and the third axis direction is defined as the third plane 130 (see Figure 7(a)), and the angle bisector of the angle between the first axis direction and the third axis direction in the third plane 130 is defined as the third bisector 208. In this embodiment, when viewing the mutual loop portion (third mutual loop portion 66) of the intersection 47 of the first tubular body 41 and the third tubular body 43 in a direction parallel to the third bisector 208 (direction of arrow B in Figure 1), the loop depth L3 of the loop between the zigzag extension portion 50 of the second tubular body 42 and the zigzag extension portion 50 of the third tubular body 43 when viewing the mutual loop portion (second mutual loop portion 64) of the intersection 46 of the second tubular body 42 and the third tubular body 43 in a direction parallel to the second bisector 207 (direction of arrow C in Figure 1) is deeper than the loop depth (dimension L2 shown in Figure 7(b)) of the intersection 46 of the second tubular body 42 and the third tubular body 43 (direction of arrow C in Figure 1). This allows for greater flexibility in the stent 100, enabling the angle R1 between the second tubular body 42 and the third tubular body 43 to bend in the direction of opening (away from each other). Therefore, when the stent 100 is implanted, the second tubular body 42 and the third tubular body 43 can bend more effectively in the direction of moving away from each other while suppressing deformation of their mesh structure 40a. In this context, "the depth of the loop between the zigzag extension 50 of the first tubular body 41 and the zigzag extension 50 of the third tubular body 43" refers to the maximum opening width of the third mutual loop section 66, and the maximum separation distance between the wire of the first tubular body 41 and the wire of the second tubular body 42 that constitute the third mutual loop section 66. More specifically, in this embodiment, it refers to the maximum separation distance between the peaks 57 and valleys 58 (details described later) that constitute the third mutual loop section 66.

[0014] In this embodiment, the depth L3 of the loop between the zigzag extension 50 of the second tubular body 42 and the zigzag extension 50 of the third tubular body 43 is preferably 1.1 to 5 times the depth L2 of the loop between the zigzag extension 50 of the first tubular body 41 and the zigzag extension 50 of the third tubular body 43, more preferably 1.2 to 4 times the depth L3, and even more preferably 1.3 to 3.7 times the depth L3.

[0015] In the following description, unless otherwise specified, the positional relationships and shapes of the parts of the stent 100 refer to the positional relationships and shapes of the stent 100 in its expanded diameter state.

[0016] As described above, the stent 100 includes a first tubular body 41 which constitutes the main pipe 10, a second tubular body 42 which constitutes the first branch pipe 20, and a third tubular body 43 which constitutes the first branch pipe 20. As shown in Figures 1 and 2, the first tubular body 41, the second tubular body 42, and the third tubular body 43 are each formed in a cylindrical shape with a mesh structure 40a. The luminal region of the first tubular body 41 is in communication with the luminal region of the second tubular body 42 and the luminal region of the third tubular body 43, respectively, on the side of the stent bifurcation 15. For example, the second axial direction of the second tubular body 42 and the third axial direction of the third tubular body 43 are inclined with respect to the first axial direction of the first tubular body 41, and the overall shape of the stent 100 is Y-shaped.

[0017] As shown in Figure 2, the first tubular body 41 to the third tubular body 43 are each individually formed by a single wire. In each of the first tubular body 41 to the third tubular body 43, one end and the other end of a single wire are crimped and fixed to each other at the lowest stage of the mesh structure 40a (for example, via one of the multiple marker portions 91 described later). The material of the wire is not particularly limited and may be a metal or a resin. The wire diameter (outer diameter) is not particularly limited, but is preferably, for example, 0.05 mm or more and 0.5 mm or less. In the present invention, the wire diameters of each wire in the first tubular body 41 to the third tubular body 43 may be the same size as each other, or they may be different sizes. That is, for example, the wire diameters of each wire in the second tubular body 42 and the third tubular body 43 may be the same size as each other, and smaller than the wire diameter of the wire in the first tubular body 41.

[0018] In the tubular body 40, the zigzag extension portion 50 of each stage 52 extends approximately one full turn in the circumferential direction while oscillating in a zigzag pattern, forming a diagonal grid-like mesh structure 40a. Each of the multiple zigzag extensions 50 of the tubular body 40 has a shape in which a first extension 55 extending in a first inclination direction (upward to the right in Figure 5) and a second extension 56 extending in a second inclination direction opposite to the first inclination direction (downward to the right in Figure 5) are alternately repeated. The number of first extensions 55 and second extensions 56 in the zigzag extension 50 of each stage 52 can be changed according to the outer diameter of the tubular body 40 and the desired mesh size of the mesh structure 40a. The zigzag extensions 50 of adjacent steps 52 have shapes that are inverted relative to each other in the axial direction. In other words, in Figure 5, the zigzag extensions 50 of odd-numbered steps from the top alternately consist of a first extension 55 and a second extension 56 from left to right, while the zigzag extensions 50 of even-numbered steps from the top alternately consist of a second extension 56 and a first extension 55 from left to right. In Figure 5, the first tubular body 41 is shown as the tubular body 40, but the mesh structures 40a of the second tubular body 42 and the third tubular body 43 are formed in the same way as the first tubular body 41. That is, each of the zigzag extensions 50 of the second tubular body 42 and the third tubular body 43 also has a shape in which the first extension 55 and the second extension 56 are alternately repeated.

[0019] In the multiple zigzag extensions 50 of the tubular body 40, the length dimension (dimension in the extension direction) of each first extension 55 and the length dimension (same as above) of each second extension 56 are set to be approximately the same length. Furthermore, each first extension portion 55 is set to have the same length dimension as each second extension portion 56. Furthermore, in the multiple zigzag extensions 50, the inclination angle of the first extension 55 with respect to the axis of the tubular body 40 and the inclination angle of the second extension 56 with respect to the axis are set to be the same dimension. Furthermore, the inclination angles of each first extension 55 are set to be the same as those of each other, and the inclination angles of each second extension 56 are also set to be the same as those of each other. However, in the present invention, for example, in a plurality of zigzag extensions 50, the first extension 55 and the second extension 56 may be set to have equivalent length dimensions (dimensions in the extension direction) and inclination angles, or they may be set to have different length dimensions and inclination angles. Also, each first extension 55 may be set to have equivalent length dimensions and inclination angles, or they may be set to have different length dimensions and inclination angles. Similarly, each second extension 56 may be set to have equivalent length dimensions and inclination angles, or they may be set to have different length dimensions and inclination angles.

[0020] In this embodiment, as an example, the second tubular body 42 and the third tubular body 43 are set to have the same outer diameter and length dimensions (dimensions in the respective axial directions). More specifically, in the second tubular body 42 and the third tubular body 43, the number of zigzag extensions 50 (number of steps 52), and the number of first extensions 55 and second extensions 56 in the zigzag extension 50 of each step 52 are the same. On the other hand, the first tubular body 41 has a larger outer diameter and length (dimensions in the first axial direction) than the second tubular body 42 and the third tubular body 43, respectively. More specifically, in the first tubular body 41, the number of zigzag extensions 50 (number of steps 52) is greater than the number of zigzag extensions 50 (number of steps 52) in the second tubular body 42 and the third tubular body 43, respectively. Also, in the first tubular body 41, the number of first extensions 55 and second extensions 56 in the zigzag extensions 50 of each step 52 is greater than the number of first extensions 55 and second extensions 56 in the zigzag extensions 50 of each step 52 in the second tubular body 42 and the third tubular body 43, respectively. However, the present invention is not limited to this example, and the second tubular body 42 and the third tubular body 43 may be set to have different outer diameters and lengths, or each of the first tubular body 41 to the third tubular body 43 may be set to have the same outer diameter and length. More specifically, in the first tubular body 41 to the third tubular body 43, the number of zigzag extensions 50 (number of steps 52), and the number of first extensions 55 and second extensions 56 in the zigzag extension 50 of each step 52 may be different from or the same from each other, depending on the desired outer diameter and length dimensions. Furthermore, in the present invention, the length dimensions of the first extension portion 55 and the length dimensions of the second extension portion 56 of each of the first tubular body 41 to the third tubular body 43 may be set to approximately the same length dimensions, or they may be set to different length dimensions.

[0021] As described above, each zigzag extension 50, after swinging in a zigzag pattern, loops with the zigzag extension 50 of the adjacent stage 52 to form a mutual loop section 60. The corner of the boundary between the first extension 55 and the second extension 56 that has an upward convex shape in Figure 5 is referred to as the peak 57, and the corner of the boundary between the first extension 55 and the second extension 56 that has a downward convex shape in Figure 5 is referred to as the valley 58. In each reciprocal loop section 60, the valley section 58 of one zigzag extension section 50 and the peak section 57 of the other zigzag extension section 50 are each loop-shaped. The reciprocal loop section 60 is formed when the valley section 58 of one zigzag extension section 50 and the peak section 57 of the other zigzag extension section 50 pass under each other's loops and their extension directions are reversed. In the mesh structure 40a of the tubular body 40, each valley 58 of the zigzag extension 50 of each stage 52 loops with each peak 57 of the zigzag extension 50 of the stage below to form a reciprocal loop section 60.

[0022] Furthermore, the tubular body 40 has a plurality of connecting parts 70 (see Figure 5) that connect adjacent zigzag extensions 50 in the axial direction of the tubular body 40. In this embodiment, the connecting portion 70 includes a first inclined portion 72 extending in a first inclination direction (upward direction to the right in Figure 5) and a second inclined portion 74 extending in a second inclination direction opposite to the first inclination direction (downward direction to the right in Figure 5). The first inclined portion 72 connects the second extension portion 56 of one zigzag extension portion 50 to the second extension portion 56 of another zigzag extension portion 50 that is in axial proximity to the said second extension portion 56. Similarly, the second inclined portion 74 connects the first extension portion 55 of one zigzag extension portion 50 to the first extension portion 55 of another zigzag extension portion 50 that is in axial proximity to the first extension portion 55. As shown in Figure 5, the first inclined portion 72 and the second inclined portion 74 do not loop around each other, but rather intersect each other in an X-shape. In this way, each of the multiple zigzag extensions 50 of the tubular body 40 is connected to one another by the connecting portion 70. Note that the multiple connection points 70 are not shown in Figures 1, 2, and 8.

[0023] As described above, the zigzag extension 50 at one end 41a of the first tubular body 41 (the uppermost zigzag extension 50 in Figures 1 and 2 in this embodiment) loops with the zigzag extension 50 at one end 42a of the second tubular body 42 (the lowermost zigzag extension 50 in Figures 1 and 2 in this embodiment) to form a first mutual loop section 62. More specifically, each peak 57 of a part of the zigzag extension 50 at one end 41a of the first tubular body 41 loops with each valley 58 of a part of the zigzag extension 50 at one end 42a of the second tubular body 42 to form a plurality of first mutual loop sections 62. When crimping and fixing one end 42aa and the other end 42ab (see Figure 3) of a single wire that forms the second tubular body 42 to each other, the wire is looped around the zigzag extension 50 of one end 41a of the first tubular body 41, as shown above. Similarly, the zigzag extension 50 at one end 41a of the first tubular body 41 loops with the zigzag extension 50 at one end 43a of the third tubular body 43 (in this embodiment, the lowest zigzag extension 50 in Figures 1 and 2) to form a third mutual loop section 66. More specifically, the remaining peaks 57 of the zigzag extension 50 at one end 41a of the first tubular body 41 (each peak 57 that is not looped with one end 42a of the second tubular body 42) loop with some of the valleys 58 of the zigzag extension 50 at one end 43a of the third tubular body 43 to form a plurality of third mutual loop sections 66. When crimping one end 43aa and the other end 43ab (see Figure 3) of a single wire forming the third tubular body 43 together, the wire is looped around the zigzag extension 50 of one end 41a of the first tubular body 41, as shown above. Furthermore, the zigzag extension 50 at one end 42a of the second tubular body 42 loops with the zigzag extension 50 at one end 43a of the third tubular body 43 to form a second mutual loop section 64. More specifically, the remaining valleys 58 of the zigzag extension 50 at one end 42a of the second tubular body 42 (the valleys 58 that do not loop with one end 41a of the first tubular body 41) loop with the remaining valleys 58 of the zigzag extension 50 at one end 43a of the third tubular body 43 (the valleys 58 that do not loop with one end 41a of the first tubular body 41) to form a second mutual loop section 64. When crimping and fixing one end 42aa and the other end 42ab of a single wire forming the second tubular body 42 (or third tubular body 43) to each other, the wire is looped around the zigzag extension 50 of one end 43a of the third tubular body 43 (or second tubular body 42) in this manner. In this way, the stent branch portion 15 is formed in the stent 100.

[0024] In this embodiment, as shown in Figure 6(a), when viewing the mutual loop portion (first mutual loop portion 62) of the intersection 45 between the first tubular body 41 and the second tubular body 42 in a direction parallel to the first bisector 206, one of the multiple first mutual loop portions 62a is positioned so as to coincide with the axis 201 of the first tubular body 41 and the axis 202 of the second tubular body 42 in the circumferential direction. Similarly, as shown in Figure 7(a), when viewing the mutual loop portion (third mutual loop portion 66) of the intersection 47 between the first tubular body 41 and the third tubular body 43 in a direction parallel to the third bisector 208, one of the multiple third mutual loop portions 66a is positioned so as to coincide with the axis 201 of the first tubular body 41 and the axis 203 of the third tubular body 43 in the circumferential direction. Furthermore, when viewing the second mutual loop portion 64 at the intersection 46 of the second tubular body 42 and the third tubular body 43 in a direction parallel to the second bisector 207 (the direction of arrow C shown in Figure 1), the second mutual loop portion 64 is positioned so as to coincide with the axis 201 of the first tubular body 41 and the axis 203 of the third tubular body 43 in the circumferential direction. In the present invention, at least the depth L3 of the loop of the second mutual loop portion 64 is greater than the depth L1 of the loop of the first mutual loop portion 62a. More preferably, the depth L3 of the loop of the second mutual loop portion 64 is greater than the depth of all the loops of the first mutual loop portion 62 at the intersection 45 of the first tubular body 41 and the second tubular body 42. Similarly, in the present invention, it is sufficient that the loop depth L3 of the second mutual loop portion 64 is deeper than the loop depth L2 of the third mutual loop portion 66a. More preferably, the loop depth L3 of the second mutual loop portion 64 is deeper than the loop depth of all the third mutual loop portions 66 at the intersection 47 of the first tubular body 41 and the third tubular body 43.

[0025] Here, as shown in Figure 1, in this embodiment, the stent 100 has a coating film 80 that covers both the first tubular body 41 and the second tubular body 42 together. Note that the coating film 80 is not shown in Figures 2 and 5. The first condition is that when the intersection 45 of the second tubular body 42 and the first tubular body 41 is deformed so that the second axial direction extends parallel to the first axial direction, the pair of zigzag extensions 50 constituting the mutual loop portion (first mutual loop portion 62) between the zigzag extensions 50 of the first tubular body 41 and the zigzag extensions 50 of the second tubular body 42 engage with each other, and the pair of zigzag extensions 50 pull each other in a direction that separates them. Furthermore, when the intersection 47 of the third tubular body 43 and the first tubular body 41 is deformed so that the third axis direction extends parallel to the first axis direction, the second condition is that, with respect to the reciprocal loop portion (third reciprocal loop portion 66) between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the third tubular body 43, the pair of zigzag extension portions 50 constituting the reciprocal loop portion (third reciprocal loop portion 66) engage with each other, and the pair of zigzag extension portions 50 pull each other in a direction that separates them. The stent 100 according to this embodiment satisfies at least one of the first and second conditions.

[0026] With this configuration, when the first branch pipe 20 and the second branch pipe 30 are bent so that the Y-shaped stent 100 becomes approximately I-shaped overall (see Figure 4), the wire at one end 41a of the first tubular body 41 and the wire at one end 42a of the second tubular body 42 (or third tubular body 43) engage (changing from a state of simply being loosely looped to a state of being directly in contact and engaged with each other), resulting in a pulling state. As a result, when the stent 100 is housed in the outer sheath described above, the zigzag extension 50 of the first tubular body 41 and the zigzag extension 50 of the second tubular body 42 (or third tubular body 43) pull against each other in a direction that separates them at the first mutual loop section 62 (or third mutual loop section 66). Therefore, the deformation of the coating film 80 is not limited to a local deformation at the first mutual loop section 62 (same as above), but extends to positions separated from the first mutual loop section 62 (same as above). Thus, it is possible to suppress concentrated load on the coating film 80 at the first mutual loop section 62 (same as above), and to distribute the load acting on the coating film 80 when the stent 100 is housed.

[0027] In this embodiment, the stent 100 satisfies both the first and second conditions described above. This prevents concentrated stress on the coating film 80 at both the first mutual loop portion 62 and the third mutual loop portion 66 when the stent 100 is housed in the outer sheath, thereby better distributing the load acting on the coating film 80 when the stent 100 is housed.

[0028] More specifically, in a state where the intersection 45 of the second tubular body 42 and the first tubular body 41 is deformed so that the second axial direction extends parallel to the first axial direction, the depth of the loop between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the second tubular body 42 (L4 shown in Figure 9(b)) is preferably 2 / 3 or less of the loop depth L1 between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the second tubular body 42, and more preferably 1 / 2 or less of the depth L1. With this configuration, when the stent 100 is housed in the outer sheath, the wire of the main pipe 10 and the wire of the first branch pipe 20 engage and pull against each other more effectively. Similarly, in a state where the intersection 47 of the third tubular body 43 and the first tubular body 41 is deformed so that the third axial direction extends parallel to the first axial direction, the depth of the loop (not shown) between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the third tubular body 43 is preferably 2 / 3 or less of the loop depth L2 between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the third tubular body 43, and more preferably 1 / 2 or less of the loop depth L2. With this configuration, when the stent 100 is housed in the outer sheath, the wire of the main pipe 10 and the wire of the second branch pipe 30 engage and pull against each other more effectively.

[0029] Furthermore, in this embodiment, when the intersection 45 of the second tubular body 42 and the first tubular body 41 is deformed so that the second axial direction extends parallel to the first axial direction, the zigzag extension portion 50 at one end 42a of the second tubular body 42 and the zigzag extension portion 50 one level above it (the upper level in Figure 9(a)) also engage with each other, causing the pair of zigzag extension portions 50 to pull each other in a direction that separates them. Similarly, when the intersection 47 of the third tubular body 43 and the first tubular body 41 is deformed so that the third axis direction extends parallel to the first axis direction, the zigzag extension portion 50 at one end 43a of the third tubular body 43 and the zigzag extension portion 50 one level above it also engage with each other, causing the pair of zigzag extension portions 50 to pull apart from each other. This allows for a more even distribution of the load acting on the coating membrane 80 when the stent 100 is placed inside.

[0030] In this embodiment, the stent 100 has a covering film 80 that covers the first tubular body 41, the second tubular body 42, and the third tubular body 43 together. The coating film 80 has a first portion 81 that covers the first tubular body 41, a second portion 82 that covers the second tubular body 42, and a third portion 83 that covers the third tubular body 43. A first boundary line 86, which is a circumferential rib or groove, may be formed at the boundary between the first part 81 and the second part 82. Furthermore, a second boundary line 87, which is a circumferential rib or groove, may be formed at the boundary between the first part 81 and the third part 83. In this case, a third condition is set that the mutual loop portion (first mutual loop portion 62) between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the second tubular body 42 is positioned to avoid the intersection 112 between the first boundary line 86 and the first plane 110, and the plane including the first axis direction and the third axis direction is set as the third plane 130. Furthermore, a fourth condition is that the mutual loop portion (third mutual loop portion 66) between the zigzag extension portion 50 of the first tubular body 41 and the zigzag extension portion 50 of the third tubular body 43 is positioned to avoid the intersection 132 between the second boundary line 87 and the third plane 130. The stent 100 according to this embodiment satisfies at least one of the third and fourth conditions.

[0031] In the stent 100, the intersection 112 between the first boundary line 86 and the first plane 110 (or the intersection 132 between the second boundary line 87 and the third plane 130) and its vicinity are the points where the coating membrane 80 is subjected to the greatest load when the stent 100 is housed. In contrast, with the above-described configuration, since the first mutual loop section 62 is positioned to avoid the intersection 112 (or the third mutual loop section 66 is positioned to avoid the intersection 132), it is possible to suppress the rupture of the coating film 80 along the first boundary line 86 (or the second boundary line 87) when accommodating the stent 100.

[0032] In this embodiment, the stent 100 satisfies both the third and fourth conditions described above. With this configuration, the first mutual loop section 62 is positioned to avoid the intersection 112, and the third mutual loop section 66 is positioned to avoid the intersection 132. Therefore, it is possible to prevent the coating film 80 from breaking along the first boundary line 86, and to prevent the coating film 80 from breaking along the second boundary line 87.

[0033] The coating film 80 is made of, for example, silicone rubber. However, the materials constituting the coating film 80 are not limited to this example and may be made of resin materials such as urethane, polytetrafluoroethylene, and polyethylene. The coating film 80 is formed, for example, by impregnating the tubular body 40 with a resin material, and is a cylindrical film in the same layer as the tubular body 40. More specifically, the first part 81 is a cylindrical film in the same layer as the first tubular body 41, the second part 82 is a cylindrical film in the same layer as the second tubular body 42, and the third part 83 is a cylindrical film in the same layer as the third tubular body 43. One end of the first section 81 (the end on the stent branching section 15 side) is connected to one end of the second section 82 and one end of the third section 83, respectively, and at that end, the portion excluding the connection point with the second section 82 and the third section 83 is closed. In this invention, the stent 100 does not necessarily have to be equipped with a coating film 80; for example, it may be a bare stent.

[0034] The first boundary line 86 is formed, for example, on the inner circumferential surface of the coating film 80, in a circumferential manner along the circumferential direction of the second tubular body 42. Similarly, the second boundary line 87 is formed in a circumferential manner along the circumferential direction of the third tubular body 43, for example, on the inner circumferential surface of the coating film 80. In this invention, the stent 100 does not necessarily have a first boundary line 86 and a second boundary line 87, and in the coating film 80, for example, the first portion 81 to the third portion 83 may be smoothly connected to one another.

[0035] Furthermore, in this embodiment, the angle R1 between the second axial direction and the third axial direction is preferably 75° or less. This configuration allows for a reduction in the amount of bending (bending angle) of the first branch tube 20 and the second branch tube 30 when bending the Y-shaped stent 100 so that its overall shape becomes approximately I-shaped (see Figure 4). Therefore, it is possible to suppress concentrated stress on the covering membrane 80 at the intersection 45 between the second tubular body 42 and the first tubular body 41, and at the intersection 47 between the third tubular body 43 and the first tubular body 41. Furthermore, since the structural strength of the stent 100 in the first axial direction can be adequately ensured, it is possible to suppress buckling of the stent 100 when it is placed in a biological lumen.

[0036] As shown in Figures 1 and 2, the stent 100 is equipped with multiple radiopaque marker portions 91. When implanting the stent 100, the marker portions 91 can be used as indicators to position the stent 100 relative to the biological lumen. In this embodiment, multiple marker portions 91 are formed on the tubular body 40 (more specifically, on each of the first tubular body 41 to the third tubular body 43). The multiple marker portions 91 are provided, for example, at multiple locations in the circumferential direction of the tubular body 40, and also at multiple locations in the axial direction of the tubular body 40.

[0037] Although embodiments have been described above with reference to the drawings, these are merely examples of the present invention, and the present invention is not limited to the above embodiments. It also includes various modifications, improvements, and other forms as long as the objectives of the present invention are achieved.

[0038] Furthermore, the various components of the stent 100 do not need to be independent entities; it is permissible for multiple components to be formed as a single member, for one component to be made up of multiple members, for one component to be part of another component, and for parts of one component to overlap with parts of another component.

[0039] This embodiment encompasses the following technical concepts. (1) A stent having a main pipe and a first branch pipe and a second branch pipe that branch off from a stent branch section which is one end of the main pipe, The main pipe, the first branch pipe, and the second branch pipe each have a tubular body with a mesh structure formed by weaving wires. The mesh structure includes a plurality of steps arranged at offset positions in the axial direction of the tubular body, and each wire includes a plurality of zigzag extensions that extend in the circumferential direction of the tubular body while swinging in a zigzag pattern in the axial direction at each step, each zigzag extension connects to a zigzag extension of the adjacent step at the end of its circumferential extension, and each zigzag extension loops with the zigzag extension of the adjacent step at the end of its zigzag swing to form a mutual loop section. The zigzag extension at one end of the first tubular body, which constitutes the main pipe, loops with the zigzag extension at one end of the second tubular body, which constitutes the first branch pipe, forming a mutual loop section, and also loops with the zigzag extension at one end of the third tubular body, which constitutes the second branch pipe, forming a mutual loop section. The zigzag extension at one end of the second tubular body loops with the zigzag extension at one end of the third tubular body to form a mutual loop portion. The axial direction of the first tubular body is defined as the first axial direction, The axial direction of the second tubular body is defined as the second axial direction, The axial direction of the third tubular body is defined as the third axial direction, The plane containing the first axis direction and the second axis direction is defined as the first plane. The plane containing the second axis direction and the third axis direction is defined as the second plane. In the first plane, the angle bisector of the angle between the first axis direction and the second axis direction is defined as the first bisector. If the angle bisector of the angle between the second axis direction and the third axis direction in the second plane is defined as the second bisector, When viewing the mutual loop portion at the intersection of the first tubular body and the second tubular body in a direction parallel to the first bisector, the depth of the loop between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body is greater than the depth of the loop between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body. When viewing the mutual loop portion at the intersection of the second tubular body and the third tubular body in a direction parallel to the second bisector, the depth of the loop between the zigzag extension portion of the second tubular body and the zigzag extension portion of the third tubular body is greater than the depth of the zigzag extension portion of the third tubular body. A deep stent. (2) Having a coating film that covers the first tubular body and the second tubular body together, When the intersection of the second tubular body and the first tubular body is deformed so that the second axial direction extends parallel to the first axial direction, the first condition is that, with respect to the mutual loop portion between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body, the pair of zigzag extension portions constituting the mutual loop portion engage with each other and pull the pair of zigzag extension portions apart from each other. When the intersection of the third tubular body and the first tubular body is deformed so that the third axial direction extends parallel to the first axial direction, if the second condition is that the pair of zigzag extensions constituting the mutual loop portion between the zigzag extension of the first tubular body and the zigzag extension of the third tubular body engage with each other and pull the pair of zigzag extensions apart, A stent according to (1) that satisfies at least one of the first and second conditions. (3) Having a coating film that covers the first tubular body, the second tubular body and the third tubular body together, The coating film has a first portion that covers the first tubular body, a second portion that covers the second tubular body, and a third portion that covers the third tubular body. A first boundary line, which is a circumferential rib or groove, is formed at the boundary between the first part and the second part. A second boundary line, which is a circumferential rib or groove, is formed at the boundary between the first part and the third part. A third condition is that the mutual loop portion between the zigzag extension of the first tubular body and the zigzag extension of the second tubular body is positioned to avoid the intersection of the first boundary line and the first plane. The plane containing the first axis direction and the third axis direction is defined as the third plane. If the fourth condition is that the mutual loop portion between the zigzag extension of the first tubular body and the zigzag extension of the third tubular body is positioned to avoid the intersection of the second boundary line and the third plane, A stent according to (1) or (2) that satisfies at least one of the conditions of the third and fourth conditions. (4) The stent according to (1) or (2), wherein the angle between the second axis direction and the third axis direction is 75° or less. [Explanation of Symbols]

[0040] 10 Main manager 15 Stent branch 20 1st branch pipe 30 Second branch pipe 40 Tubular body 40a Mesh structure 41 First tubular body 41a one end 42 Second tubular body 42a one end 42aa One end of the wire 42ab Other end of the wire 43 Third tubular body 43a one end 43aa One end of the wire 43ab Other end of the wire 45 Intersection of the first tubular body and the second tubular body 46. ​​Intersection of the second tubular body and the third tubular body 47 Intersection of the first tubular body and the third tubular body 50 Multiple zigzag extensions 52 steps 55 1st extension part 56 Second extension part 57 Yamabe 58 Tanibe 60 Mutual Loop Section 62, 62a First mutual loop section (mutual loop section between the zigzag extension of the first tubular body and the zigzag extension of the second tubular body) 64. Second mutual loop section (mutual loop section between the zigzag extension of the second tubular body and the zigzag extension of the third tubular body) 66 Third mutual loop section (mutual loop section between the zigzag extension of the first tubular body and the zigzag extension of the third tubular body) 70 Connection part 72 1st slope part 74 2nd slope part 80 Coating membrane 81 Part 1 82 Part 2 83 Part 3 86. First Boundary Line 87. Second Boundary Line 91 Marker section 100 Stents (Covered Stents) 110 1st plane 112 Intersection of the first boundary line and the first plane 120 2nd plane 130 3rd plane 132 Intersection of the second boundary line and the third plane 201 1st axis center 202 2nd axis center 203 3rd axis center 206 First bisector 207 Second bisector 208 Third bisector

Claims

1. A stent having a main pipe and a first branch pipe and a second branch pipe that branch off from a stent branch section which is one end of the main pipe, The main pipe, the first branch pipe, and the second branch pipe each have a tubular body with a mesh structure formed by weaving wires. The mesh structure includes a plurality of steps arranged at offset positions in the axial direction of the tubular body, and each wire includes a plurality of zigzag extensions that extend in the circumferential direction of the tubular body while swinging in a zigzag pattern in the axial direction at each step, each zigzag extension connects to a zigzag extension of the adjacent step at the end of its circumferential extension, and each zigzag extension loops with the zigzag extension of the adjacent step at the end of its zigzag swing to form a mutual loop section. The zigzag extension at one end of the first tubular body, which constitutes the main pipe, loops with the zigzag extension at one end of the second tubular body, which constitutes the first branch pipe, to form a mutual loop section, and also loops with the zigzag extension at one end of the third tubular body, which constitutes the second branch pipe, to form a mutual loop section. The zigzag extension at one end of the second tubular body loops with the zigzag extension at one end of the third tubular body to form a mutual loop. The axial direction of the first tubular body is defined as the first axial direction, The axial direction of the second tubular body is defined as the second axial direction, The axial direction of the third tubular body is defined as the third axial direction, The plane containing the first axial direction and the second axial direction is defined as the first plane. The plane including the second axis direction and the third axis direction is defined as the second plane. In the first plane, the angle bisector of the angle between the first axis direction and the second axis direction is defined as the first bisector. If the angle bisector of the angle between the second axis direction and the third axis direction in the second plane is defined as the second bisector, When viewing the mutual loop portion at the intersection of the first tubular body and the second tubular body in a direction parallel to the first bisector, the depth of the loop between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body is greater than the depth of the loop between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body. When viewing the mutual loop portion at the intersection of the second tubular body and the third tubular body in a direction parallel to the second bisector, the depth of the loop between the zigzag extension portion of the second tubular body and the zigzag extension portion of the third tubular body is greater than the depth of the zigzag extension portion of the third tubular body. A deep stent.

2. It has a coating film that covers the first tubular body and the second tubular body together, When the intersection of the second tubular body and the first tubular body is deformed so that the second axial direction extends parallel to the first axial direction, the first condition is that, with respect to the mutual loop portion between the zigzag extension portion of the first tubular body and the zigzag extension portion of the second tubular body, the pair of zigzag extension portions constituting the mutual loop portion engage with each other and pull the pair of zigzag extension portions apart from each other. When the intersection of the third tubular body and the first tubular body is deformed so that the third axial direction extends parallel to the first axial direction, if the second condition is that the pair of zigzag extensions constituting the mutual loop portion between the zigzag extension of the first tubular body and the zigzag extension of the third tubular body engage with each other and pull the pair of zigzag extensions apart, A stent according to claim 1 that satisfies at least one of the first and second conditions.

3. It has a coating film that covers the first tubular body, the second tubular body, and the third tubular body together, The coating film has a first portion that covers the first tubular body, a second portion that covers the second tubular body, and a third portion that covers the third tubular body. A first boundary line, which is a circumferential rib or groove, is formed at the boundary between the first part and the second part. A second boundary line, which is a circumferential rib or groove, is formed at the boundary between the first part and the third part. A third condition is that the mutual loop portion between the zigzag extension of the first tubular body and the zigzag extension of the second tubular body is positioned to avoid the intersection of the first boundary line and the first plane. The plane containing the first axis direction and the third axis direction is defined as the third plane. If the fourth condition is that the mutual loop portion between the zigzag extension of the first tubular body and the zigzag extension of the third tubular body is positioned to avoid the intersection of the second boundary line and the third plane, A stent according to claim 1 or 2 that satisfies at least one of the third and fourth conditions.

4. The stent according to claim 1 or 2, wherein the angle between the second axial direction and the third axial direction is 75° or less.

Images