Stent

Abstract

The purpose of the present invention is to provide a stent having a large surface area, excellent shape followability to a blood vessel structure, and reduced diameter, the stent being capable of more appropriately maintaining a state in which the surface area is increased.　A cylindrical part 3 of a stent 1 comprises a first cylindrical part 10 having a plurality of first cells, and a second cylindrical part 20 having a plurality of second cells and inserted into the first cylindrical part 10, overlapping parts of the second cells being arranged in opening parts of the first cells in a state in which the second cylindrical part 20 is inserted into the first cylindrical part 10, a proximal side of the first cylindrical part 10, a proximal side of the second cylindrical part 20, and a distal side of a pusher wire 2 being directly or indirectly connected, and a rotation suppressing structure being provided between a first antenna part 102 provided on the proximal side of the first cylindrical part 10 and a second antenna part 202 provided on the proximal side of the second cylindrical part 20 to suppress relative rotation of the first antenna part 102 and the second antenna part 202 about the center axis.

Description

stents

[0001] The present invention relates to a stent.

[0002] 2. Description of the Related Art Catheter therapy is known in the art, in which a stent is deployed at a lesion site in a blood vessel lumen.

[0003] U.S. Pat. No. 10,390,982

[0004] As in Patent Document 1, by retrieving the stent after opening the blood flow, it is possible to reduce the risk of various complications while ensuring blood flow patency. Here, it is ideal to increase the surface area of ​​the stent (the area excluding the pore area of ​​the cells) in order to more uniformly expand the narrowed blood vessel. However, increasing the surface area of ​​the stent increases the bending rigidity of the stent, which reduces its ability to conform to the shape of the blood vessel structure and makes it difficult to insert the stent into a catheter with a small diameter.

[0005] The first object of the present invention is to provide a stent that has an excellent balance of a large surface area, conformability to the vascular structure, and ease of storage in a small-diameter catheter. The second object of the present invention is to provide a stent that can more appropriately maintain the increased surface area.

[0006] The first disclosure relates to a stent having a double-structured cylindrical portion used for expanding a narrowed portion of a biological lumen, the cylindrical portion comprising: a first cylindrical portion in which a plurality of first cells are arranged in a circumferential direction and in a central axis direction; and a second cylindrical portion in which a plurality of second cells are arranged in a circumferential direction and in a central axis direction, the second cylindrical portion having at least a region for expanding the narrowed portion of the biological lumen inserted into the first cylindrical portion; and a stent having a front end that is in contact with an opening of the first cell when at least the region for expanding the narrowed portion of the biological lumen of the second cylindrical portion is inserted into the first cylindrical portion. The stent has an overlapping portion of the second cell arranged, and the proximal side of the first cylindrical portion, the proximal side of the second cylindrical portion, and the distal side of the pusher wire are connected directly or indirectly.The stent has a rotation suppression structure between a first antenna portion provided between the proximal end of the first cylindrical portion and a region for expanding the narrowed portion of the biological lumen, and a second antenna portion provided between the proximal end of the second cylindrical portion and the region for expanding the narrowed portion of the biological lumen, which suppresses relative rotation about the central axis of the first antenna portion and the second antenna portion.

[0007] A second disclosure is a stent described in the first disclosure, wherein the distal side of the first cylindrical portion, the distal side of the second cylindrical portion, and the proximal end of the distal end shaft are directly or indirectly connected.

[0008] A third disclosure is the stent according to the first or second disclosure, wherein in the rotation suppression structure, a portion of the first antenna portion and a portion of the second antenna portion are joined to each other.

[0009] A fourth disclosure is a stent described in any one of the first to third disclosures, wherein in the rotation suppression structure, at least a portion of the first antenna portion and the second antenna portion are arranged so that their radial positions are interchanged and are configured to be able to abut against each other in the circumferential direction.

[0010] A fifth disclosure is a stent described in any one of the first to fourth disclosures, wherein, when a region of the second cylindrical portion that expands at least the narrowed portion of the biological lumen is inserted into the first cylindrical portion, the second cylindrical portion presses the first cylindrical portion radially outward.

[0011] A sixth disclosure is a stent according to any one of the first to fifth disclosures, which is used for applications in which the stent is temporarily placed in a biological lumen and then retrieved outside the body.

[0012] The seventh disclosure is a method for expanding a biological organ having a tubular structure using a stent, the stent having a double-structured cylindrical portion, the cylindrical portion comprising: a first cylindrical portion in which a plurality of first cells are arranged in a circumferential direction and a central axis direction; and a second cylindrical portion in which a plurality of second cells are arranged in a circumferential direction and a central axis direction, the second cylindrical portion having at least a region for expanding a narrowed portion of the biological lumen inserted into the first cylindrical portion, the overlapping portions of the second cells being disposed at openings of the first cells in a state in which at least the region for expanding a narrowed portion of the biological lumen of the second cylindrical portion is inserted into the first cylindrical portion, and the proximal side of the first cylindrical portion, the proximal side of the second cylindrical portion, and the distal side of a pusher wire are connected directly or indirectly. a rotation suppression structure for suppressing relative rotation about a central axis of the first antenna portion and the second antenna portion, the rotation suppression structure being disposed between the first antenna portion and the region where the narrowed portion of the biological lumen is expanded, and the second antenna portion being disposed between the proximal end of the second cylindrical portion and the region where the narrowed portion of the biological lumen is expanded; and the method includes: delivering the stent housed in a catheter in a contracted state together with the catheter through the biological organ to a planned position of expansion in the biological organ; withdrawing the catheter proximally and starting expansion of the stent from the distal side; completing expansion of the stent; and re-accommodating the expanded stent into the catheter.

[0013] According to the present invention, a stent having an excellent balance of a large surface area, conformability to the vascular structure, and diameter reduction property can be provided. Furthermore, according to the present invention, a stent capable of more appropriately maintaining an increased surface area can be provided.

[0014] 8A is a side view of a stent system 100 according to a first embodiment. FIG. 8B is a side view of a first stent body 10. FIG. 8C is a side view of a second stent body 20. FIG. 8D is a virtual development view of a portion of the first stent body 10. FIG. 8E is a virtual development view of a portion of the second stent body 20. FIG. 8F is a virtual development view of a portion of the stent 1. FIG. 8G is a virtual development view of a first body portion 101 of the first stent body 10. FIG. 8H is a diagram illustrating the outer diameter D1 of the first stent body 10 before assembly. FIG. 8I is a diagram illustrating the outer diameter D2 of the second stent body 20 before assembly. FIG. 8I is a diagram illustrating the process of inserting the second stent body 20 into the first stent body 10. FIG. 8I is a cross-sectional view taken along line s1-s1 of FIG. 1A. FIG. 8I is a partial enlarged view of region A shown in FIG. 1A. FIG. 8I is a cross-sectional view taken along line s2-s2 of FIG. 8A. FIG. 8I is a cross-sectional view taken along line s3-s3 of FIG. 8A. FIG. 8I is a side view schematically illustrating the connection between the stent 1 and the pusher wire 2 and the rotation suppression structure provided on the antenna portion 4. FIG. 8I is a cross-sectional view taken along line s4-s4 of FIG. 10A. A development view schematically showing another form of the rotation suppression structure provided on the antenna portion 4. A side view of the stent system 100A according to the third embodiment. A side view of the first stent body 10 in the third embodiment. A side view of the second stent body 20 in the third embodiment. A schematic diagram showing a procedure for dilating a stenotic site in a blood vessel using the stent 1 ...

[0015] Hereinafter, an embodiment of a stent system including a stent will be described. Note that the drawings attached to this specification are all schematic diagrams, and the shape, scale, aspect ratio, etc. may be modified or exaggerated from the actual product. Furthermore, hatching indicating the cross section of a component may be omitted as appropriate in the drawings.

[0016] In this specification, terms specifying the shape, geometric conditions, and the extent of these, such as "direction," include not only the strict meaning of the term but also the range that can be roughly considered to be that direction. In this specification, the axial direction LD refers to the side closer to the practitioner (proximal) as the LD1 side, and the side farther from the practitioner (distal) as the LD2 side, and the direction perpendicular to the axial direction LD refers to the radial direction RD. The axial direction LD refers to the direction parallel to the central axis CA (central axis direction). The central axis CA refers to a line that passes through the center of the stent 1 in the radial direction RD along the longitudinal direction, as shown in FIG. 1, for example. In addition, in this specification, the direction in which the cells are arranged is referred to as the circumferential direction OD.

[0017] (First embodiment) Fig. 1 is a side view of a stent system 100 according to the first embodiment. Fig. 2A is a side view of a first stent body 10. Fig. 2B is a side view of a second stent body 20. Fig. 3A is a virtual developed view of a portion of the first stent body 10. Fig. 3B is a virtual developed view of a portion of the second stent body 20. Fig. 3C is a virtual developed view of a portion of a stent 1. Fig. 4 is a virtual developed view of the first body portion 101 of the first stent body 10. Fig. 5A is a view illustrating the outer diameter D1 of a single first stent body 10. Fig. 5B is a view illustrating the outer diameter D2 of a single second stent body 20. Fig. 6 is a view illustrating the process of inserting the second stent body 20 into the first stent body 10. Fig. 7 is a cross-sectional view taken along line s1-s1 in Fig. 1.

[0018] In the drawings, to facilitate distinction between the first stent body 10 and the second stent body 20, struts of the first stent body 10 are shown in black, and struts of the second stent body 20 are shown in white. Furthermore, in this specification, etc., "cell" refers to a strut forming a stent. "Cells" may have the same shape and size as each other, or they may differ. "Strut" refers to a portion made of the wire-like material. In this specification, etc., the opening of a cell is also referred to as an "opening portion," and the portion where struts of adjacent cells are connected or overlapped is also referred to as an "overlap portion." Within the overlap portion, the point where struts intersect is also referred to as an "intersection portion." The overlap portion may have a certain range (area). The overlap portion may include one or more intersection portions.

[0019] The stent system of the first embodiment is used, for example, to be housed in a catheter (not shown), and to dilate a narrowed or blocked blood vessel by withdrawing the stent from the catheter and expanding the diameter thereof in the lumen of the blood vessel. In the stent system, the stent is temporarily placed in the blood vessel while ensuring the patency of the blood vessel, and then withdrawn from the body. The blood vessel of the biological lumen in which the stent system is used may be a blood vessel (artery, vein) of the brain, coronary artery, upper or lower limbs, organ, etc. In the following description, the biological lumen may also be simply referred to as a "blood vessel."

[0020] As shown in FIG. 1 , the stent system 100 includes a stent 1 and a pusher wire 2. The stent 1 is a structure to be placed, for example, at a stenotic site in a blood vessel. The stent 1 is configured to have a generally cylindrical shape as a whole in its natural state. The natural state refers to a state in which the stent 1 is not contracted (an unloaded state). Although not shown, the stent 1 has an elongated cylindrical shape in its contracted state. As shown in FIG. 1 , on the proximal side LD1 of the stent 1, the first antenna portion 102 of the first stent body 10 and the second antenna portion 202 of the second stent body 20, which constitute the antenna portion 4 (described below), gradually contract in diameter toward the proximal side LD1 and are connected to the distal side LD2 of the pusher wire 2.

[0021] As shown in FIG. 1 , the stent 1 comprises a main body portion (cylindrical portion) 3 and an antenna portion 4. The main body portion 3 is a portion that dilates a narrowed portion of a biological lumen, and comprises a first stent body (first cylindrical portion) 10 and a second stent body (second cylindrical portion) 20. The first stent body 10 is a substantially cylindrical structure that is disposed on the outside of the stent 1. The second stent body 20 is a substantially cylindrical structure that is disposed on the inside of the first stent body 10. The stent 1 is configured as a two-layer stent in which the second stent body 20 is inserted into the first stent body 10. In particular, it is sufficient that at least the region of the second stent body 20 that dilates a narrowed portion of a biological lumen (the second main body portion 201 described below) is inserted into the first stent body 10.

[0022] The antenna portion 4 is a portion that converges the proximal side LD1 of the main body portion 3 to the distal side LD2 of the pusher wire 2 and is formed integrally with the main body portion 3 in the axial direction. The antenna portion 4 is composed of a first antenna portion 102 of the first stent body 10 and a second antenna portion 202 of the second stent body 20. The antenna portion 4 has a mesh pattern structure similar to the main body portion 3, but the cells that form the antenna portion 4 are designed not to support the inner wall of the blood vessel when expanded within the blood vessel. The end of the proximal side LD1 of the antenna portion 4 is connected to the distal side LD2 of the pusher wire 2. In FIG. 1 , the connection portion between the antenna portion 4 and the pusher wire 2 is not shown. In the stent 1 of the first embodiment, the distal side LD2 of the main body portion 3 is open. That is, the stent 1 of the first embodiment does not have an antenna portion on the distal side LD2 of the main body portion 3.

[0023] (First Stent Body 10) As shown in FIG. 2A , the first stent body 10 includes a first body portion 101 and a first antenna portion 102. The first body portion 101 is a self-expanding cylindrical portion. The first body portion 101 is a region of the first stent body 10 that expands a stenosed portion of a blood vessel (biological lumen). The first body portion 101 self-expands to a cylindrical shape within the blood vessel and expands the stenosed or blocked portion together with the second body portion 201 (second stent body 20), which will be described later. The self-expansion force of the first body portion 101 cooperates with the self-expansion force of the second body portion 201 to act as a force that pushes the inner wall of the blood vessel radially outward. This allows the stent 1, expanded within the blood vessel, to be placed in place. The first antenna portion 102 is a portion that converges the proximal side LD1 of the first main body portion 101 to the distal side LD2 of the pusher wire 2, and gradually reduces in diameter as it moves from the end of the proximal side LD1 of the first main body portion 101 toward the distal side LD2 of the pusher wire 2.

[0024] As shown in FIG. 3A , the first main body portion 101 of the first stent body 10 has a mesh pattern structure in which multiple outer cells (first cells) 12 are arranged in the circumferential direction OD and the axial direction (central axis direction) LD. A "cell," also referred to as an opening or compartment, refers to a frame-shaped portion surrounded by struts 11 that form the mesh pattern structure. In the following description, an outer cell at a specific position will be identified by an identification symbol and referred to as, for example, "outer cell 12f." The outer cell 12 has an opening portion 13. The opening portion is the opening portion of the cell. Adjacent outer cells 12 are connected at intersections 14.

[0025] The cell structure is not particularly specified, but may be entirely open cells or entirely closed cells. Furthermore, the cell structure may include both open and closed cells. In this specification, the definitions of open and closed cells are not uniquely specified. For example, in a closed cell including a free end, half of the region surrounded by the two sides (struts) that form the free end may be specified as an open cell (part), and the other half may be specified as a closed cell (part). Alternatively, a closed cell including a free end may be specified as an open cell, and a closed cell not including a free end may be specified as a closed cell.

[0026] As shown in FIG. 4 , the range of the first main body portion 101 in the axial direction LD corresponds to the range of the effective length VL of the first stent body 10. The range of the effective length VL refers to the range between the distal end 121 of the outer cell 12f located on the most distal side LD2 of the first main body portion 101 and the proximal end 122 of the cell 12n located on the most proximal side LD1. In the first main body portion 101, the range of the effective length VL is a region where the stenotic site of the blood vessel (biological lumen) is expanded. Within the range of the effective length VL, the first main body portion 101 can support the inner wall of the blood vessel by expanding in diameter. The effective length VL of the first stent body 10 is preferably longer than the axial length of the stenotic site and long enough to contact normal blood vessels located near the stenotic site. The effective length VL of the first stent body 10 is preferably, for example, approximately 1.3 to 2.0 times the axial length of the stenotic site.

[0027] 4 illustrates the range of the effective length VL using the first stent body 10 as an example, but the range of the effective length VL in the axial direction is substantially the same for the second stent body 20. In this embodiment, the range of the effective length VL of the first body portion 101 and the range of the effective length VL of the second body portion 201 are the same, but are not limited to this. For example, the range of the effective length VL of the first stent body 10 may be longer than the range of the effective length VL of the second stent body 20.

[0028] (Second Stent Body 20) As shown in FIG. 2B , the second stent body 20 includes a second body portion 201 and a second antenna portion 202. The second body portion 201 is a self-expanding cylindrical portion. The second body portion 201 is a region of the second stent body 20 that expands a stenosed portion of a blood vessel (biological lumen). The second body portion 201 self-expands to a cylindrical shape within the blood vessel and expands the stenosed or blocked portion together with the first body portion 101 (first stent body 10). The self-expansion force of the first body portion 101 cooperates with the self-expansion force of the first body portion 101 to act as a force pushing the inner wall of the blood vessel from the inside to the outside in the radial direction. This allows the stent 1 expanded within the blood vessel to be placed in place. The second antenna portion 202 is a portion that converges the proximal side LD1 of the second main body portion 201 to the distal side LD2 of the pusher wire 2, and gradually reduces in diameter from the end of the proximal side LD1 of the second main body portion 201 toward the distal side LD2 of the pusher wire 2.

[0029] 3B , the second main body portion 201 of the second stent body 20 has a mesh pattern structure in which a plurality of inner cells (second cells) 22 are arranged in the circumferential direction OD and the axial direction (central axis direction) LD. Like the outer cells 12 of the first main body portion 101, the inner cells 22 have openings 23. Adjacent inner cells 22 are connected at intersections 24.

[0030] 3A and 3B, in the stent 1 of the first embodiment, the outer cells 12 constituting the first stent body 10 and the inner cells 22 constituting the second stent body 20 are configured to have the same size, shape, and arrangement, for example. That is, the mesh pattern of the first stent body 10 shown in Fig. 3A and the mesh pattern of the second stent body 20 shown in Fig. 3B are substantially the same pattern. Note that the mesh patterns of the first stent body 10 and the second stent body 20 may differ in shape, density, etc.

[0031] As shown in Figure 3C, in the stent 1, the first stent body 10 and the second stent body 20 are overlapped such that the intersections 24 of the inner cells 22 are positioned at the openings 13 of the outer cells 12. Specifically, in a configuration in which the intersections 24 of the inner cells 22 are positioned at the openings 13 of the outer cells 12, the overlapping is performed such that the intersections 24 of one inner cell 22 are positioned at the openings 13 of one outer cell 12. By overlapping the mesh patterns of the stent bodies in this manner, the density of the mesh pattern is increased throughout the stent, thereby increasing the surface area of ​​the stent 1. In the stent 1 of the first embodiment, the proportion of non-opening areas per unit area of ​​the surface where the first stent body 10 and the second stent body 20 overlap is, for example, 5 to 50%.

[0032] When the second stent body 20 is inserted into the first stent body 10, the first stent body 10 and the second stent body 20 are not connected to each other in the radial direction RD. Therefore, the stent 1 allows the first stent body 10 and the second stent body 20 to deform independently in the radial, circumferential, and axial directions. Meanwhile, the proximal end LD1 of the antenna portion of each of the first stent body 10 and the second stent body 20 is connected to the distal end LD2 of the pusher wire 2. In the first embodiment, the antenna portions of the first stent body 10 and the second stent body 20 are joined by a rotation suppression structure (described below).

[0033] As described below, the stent 1 of the first embodiment is fabricated by inserting a second stent body 20, which has an outer diameter larger than that of the first stent body 10, into the first stent body 10 in a reduced diameter state. As a result, in the stent 1, the inserted second stent body 20 constantly presses the first stent body 10 outward in the radial direction RD. Therefore, the stent 1 can more firmly adhere the first stent body 10 and the second stent body 20 while maintaining a state in which the first stent body 10 and the second stent body 20 can deform independently in the radial, circumferential, and axial directions. Furthermore, the stent 1 is less likely to kink or break due to buckling in a blood vessel with a small bending radius. Note that in the aforementioned FIGS. 2A and 2B , the stent bodies are illustrated as having the same diameter.

[0034] The practitioner advances and retracts the stent 1 within the catheter or blood vessel by pushing and pulling the pusher wire 2 via an ex vivo operating unit (not shown) connected to the proximal side LD1 of the pusher wire 2.

[0035] The proximal side LD1 of the first stent body 10 (first antenna portion 102), the proximal side LD1 of the second stent body 20 (second body portion 201), and the distal side LD2 of the pusher wire 2 are directly or indirectly connected. Here, "directly connected" means, for example, that the proximal side LD1 of the first stent body 10 is connected to the distal side LD2 of the pusher wire 2, and that the proximal side LD1 of the second stent body 20 is connected to the distal side LD2 of the pusher wire 2. In this case, the position where the proximal side LD1 of the first stent body 10 is connected to the pusher wire 2 and the position where the proximal side LD1 of the second stent body 20 is connected to the pusher wire 2 may be the same as or different from each other. On the other hand, being indirectly connected refers to, for example, a configuration in which the proximal side LD1 of the first stent body 10 is connected to the distal side LD2 of the pusher wire 2, and the proximal side LD1 of the first stent body 10 is connected to the proximal side LD1 of the second stent body 20 (or a connection configuration in which the connections of the two stent bodies are reversed). In this case, the proximal side LD1 of the second stent body 20 is indirectly connected to the pusher wire 2 via the proximal side LD1 of the first stent body 10. Alternatively, this configuration refers to a configuration in which the proximal side LD1 of the first stent body 10 and the proximal side LD1 of the second stent body 20 are connected via a pipe-shaped sleeve (not shown) fitted around the distal side LD2 of the pusher wire 2. In this case, the proximal side LD1 of the first stent body 10 and the proximal side LD1 of the second stent body 20 are indirectly connected to the distal side LD2 of the pusher wire 2 via the sleeve. Thus, in this specification, "indirectly connected" includes a configuration in which one of the proximal side LD1 of the first stent body 10 or the proximal side LD1 of the second stent body 20 is directly connected to the pusher wire 2, and the other stent body is indirectly connected to the pusher wire 2 via the directly connected stent body. Examples of methods for connecting the proximal end of each stent body to the pusher wire 2 include welding, UV bonding, and impregnation with silver solder, but are not particularly limited as long as they are connection methods used in general medical devices. An example of a connection configuration between the stent 1 and the pusher wire 2 will be described in the second embodiment.

[0036] 5A and 5B, the relationship between the outer diameter D1 of a single first stent body 10 and the outer diameter D2 of a single second stent body 20 is set to satisfy LD1 < LD2. Therefore, by reducing the diameter of the second stent body 20, which has an outer diameter larger than that of the first stent body 10, to form the second stent body 20A according to the procedure indicated by the arrows in Fig. 6 and inserting this into the first stent body 10, it is possible to produce a stent 1 having a two-layer structure in which the second stent body 20 is closely attached to the inside of the first stent body 10 due to the self-expansion force of the second stent body 20. Note that for ease of understanding, Fig. 5 shows only the annular cell rows arranged in the circumferential direction in each stent body.

[0037] In the stent 1 fabricated as described above, the first stent body 10 and the second stent body 20 are in close contact with each other with no gaps in the radial direction RD due to the self-expansion force of the second stent body 20, as shown in Fig. 7. Therefore, the first stent body 10 and the second stent body 20 are less likely to be displaced relative to each other in the axial direction LD of the stent 1 (see Fig. 1).

[0038] In the first embodiment, the second stent body 20 inserted into the first stent body 10 in a contracted state is itself a self-expanding body (elastic body). Therefore, the second stent body 20 is constantly pressing the first stent body 10 outward in the radial direction RD. Therefore, even if the first stent body 10 and the second stent body 20 are not connected to each other in the radial direction, the first stent body 10 and the second stent body 20 can be more firmly adhered to each other.

[0039] Furthermore, since the first stent body 10 and the second stent body 20 of the stent 1 are not connected to each other in the radial direction, the first stent body 10 and the second stent body 20 can maintain a state in which they can deform independently in the radial, circumferential, and axial directions. Furthermore, the two-layer stent 1 has an expansion force that is the sum of the expansion force of the outer first stent body 10 and the expansion force of the inner second stent body 20. Therefore, even with the same surface area, the expansion force can be made greater than that of a single-layer stent.

[0040] The stent 1 (first stent body 10, second stent body 20) is preferably formed from a material that is highly rigid and biocompatible. While not particularly limited, such a material is preferably a material with superelastic properties, such as a nickel-titanium (Ni-Ti) alloy. The first stent body 10 and second stent body 20 can be fabricated, for example, by laser processing a substantially cylindrical tube made of the above material.

[0041] The stent 1 may also contain a drug. Here, "the stent 1 contains a drug" means that the stent 1 releasably supports the drug so that the drug can be eluted. The drug is not limited, and for example, a physiologically active substance can be used. Examples of physiologically active substances include drugs that suppress intimal hyperplasia, anticancer drugs, immunosuppressants, antibiotics, antirheumatic drugs, antithrombotic drugs, HMG-CoA reductase inhibitors, ACE inhibitors, calcium channel blockers, antihyperlipidemic drugs, anti-inflammatory drugs, integrin inhibitors, antiallergic drugs, antioxidants, GPIIbIIIa antagonists, retinoids, flavonoids and carotenoids, lipid-improving drugs, DNA synthesis inhibitors, tyrosine kinase inhibitors, antiplatelet drugs, vascular smooth muscle proliferation inhibitors, anti-inflammatory drugs, interferons, etc., and a plurality of these drugs can also be used.

[0042] The double-layered stent 1 is radially contracted from the state shown in Fig. 1 and housed in the lumen of a catheter (not shown). When the catheter is withdrawn and the stent 1 is deployed, it recovers to the shape shown in Fig. 1. The shape recovery function described above can be achieved by forming the stent 1 from an elastic material such as a superelastic alloy or a shape-memory alloy. Note that the method of manufacturing the stent 1 is not limited to laser processing, and it can also be manufactured by other methods such as cutting.

[0043] Next, the rotation suppression structures provided on the first antenna portion 102 of the first stent body 10 and the second antenna portion 202 of the second stent body 20 will be described. Fig. 8 is a partial enlarged view of region A shown in Fig. 1. Fig. 9A is a cross-sectional view taken along line s2-s2 in Fig. 8. Fig. 9B is a cross-sectional view taken along line s3-s3 in Fig. 8.

[0044] As shown in Fig. 8 , the antenna portion 4 of the first embodiment includes joints 15 and 16 as a rotation suppression structure. As shown in Fig. 9A , the joint 15 joins the strut 11 of the first antenna portion 102 (first stent body 10) to the strut 21 of the second antenna portion 202 (second stent body 20) on the radially outer side (upper side in the figure). As shown in Fig. 9B , the joint 16 joins the strut 11 of the first antenna portion 102 to the strut 21 of the second antenna portion 202 on the radially inner side (lower side in the figure). Examples of methods for joining the radially overlapping struts 11 and 21 include welding, UV bonding, and impregnation with silver brazing. Alternatively, for example, the intersecting portions of the struts 11 and 21 may be connected with a thin wire-like material. The method for joining the struts 11 and 21 is not particularly limited as long as it is a connection method commonly used in medical devices.

[0045] By providing the antenna unit 4 with the joints 15 and 16 as a rotation suppression structure, relative rotation about the central axis of the first antenna unit 102 and the second antenna unit 202 is suppressed, and therefore relative rotation about the central axis of the first main body unit 101 formed integrally with the first antenna unit 102, and the second main body unit 201 formed integrally with the second antenna unit 202 can be suppressed. Note that it is sufficient that the joints 15 and 16 are provided in at least one location in the portion where the strut 11 of the first antenna unit 102 and the strut 21 of the second antenna unit 202 overlap in the radial direction.

[0046] The stent 1 of the first embodiment described above has the following advantages, for example. The stent 1 of the first embodiment has a double-layer structure including a first stent body 10 and a second stent body 20, which are overlapped such that the intersections 24 of the inner cells 22 of the second stent body 20 are positioned at the openings 13 of the outer cells 12 of the first stent body 10 (see FIG. 3C ). Overlapping the mesh patterns of the stent bodies in this manner increases the density of the mesh pattern throughout the stent, thereby increasing the surface area of ​​the stent 1. Therefore, the stent 1 of the first embodiment can dilate a stenosed blood vessel more uniformly.

[0047] In the stent 1 of the first embodiment, when the second stent body 20 is inserted into the first stent body 10, the first stent body 10 and the second stent body 20 are not connected to each other in the radial direction. This configuration allows the first stent body 10 and the second stent body 20 to deform independently in the radial, circumferential, and axial directions, and interference that would hinder each other's deformation is unlikely to occur, thereby further increasing the flexibility of the stent as a whole. As such, the stent 1 of the first embodiment has excellent shape-following ability to the vascular structure, even when its surface area is increased, because its bending rigidity does not become too high.

[0048] In the stent 1 of the first embodiment, the first stent body 10 and the second stent body 20 can deform independently in the radial, circumferential, and axial directions, so that when the stent 1 is contracted, the struts in each layer can be contracted without interfering with each other. Because the stent 1 of the first embodiment has excellent contraction properties, it can be easily accommodated in a catheter with a small diameter compared to a stent with a large surface area due to a single-layer mesh pattern. Therefore, the stent 1 of the first embodiment has a large surface area and is excellent in terms of shape conformability to the vascular structure and contraction properties.

[0049] The stent 1 of the first embodiment includes joints 15 and 16 as a rotation suppression structure in the antenna portion 4 having a double structure. Therefore, when the stent 1 is repeatedly contracted and expanded, relative rotation about the central axis of the first body portion 101, which is integrally formed with the first antenna portion 102, and the second body portion 201, which is integrally formed with the second antenna portion 202, can be suppressed. As a result, as shown in FIG. 3C , the intersections 24 of the inner cells 22 of the second body portion 201 can be maintained in the openings 13 of the outer cells 12 of the first body portion 101, thereby more appropriately maintaining the increased surface area. The effect of the rotation suppression structure described above is exerted in the antenna portion 4, and does not prevent the first body portion 101 and the second body portion 201 from independently deforming in the radial, circumferential, and axial directions in the main body portion 3.

[0050] Incidentally, if the antenna portion 4 does not have a rotation suppression structure, the first body portion 101 and the second body portion 201 will rotate relatively about the central axis when the stent 1 is repeatedly contracted and expanded, and this may result in misalignment, for example, such that the opening portion 13 of the outer cell 12 of the first body portion 101 overlaps the opening portion 23 of the inner cell 22 of the second body portion 201. When the struts 11 forming the outer cell 12 of the first body portion 101 and the struts 21 forming the inner cell 22 of the second body portion 201 overlap in the circumferential direction in this way, the surface area of ​​the stent 1 is reduced, thereby compromising the benefits of a two-layer stent. However, the stent 1 of the first embodiment includes the joints 15 and 16 in the antenna portion 4 as a rotation suppression structure. This prevents the first body portion 101 and the second body portion 201 from rotating relative to each other around the central axis, even when the stent 1 is repeatedly contracted and expanded. This prevents the intersections 24 of the inner cells 22 of the second body portion 201 from being positioned at the openings 13 of the outer cells 12 of the first body portion 101. This allows the increased surface area, a benefit of a two-layer stent, to be more appropriately maintained. Experiments conducted by the inventors have confirmed that the problem of the first body portion 101 and the second body portion 201 rotating relative to each other around the central axis when the stent 1 is repeatedly contracted and expanded, is likely to occur in curved blood vessels. Therefore, the stent 1 of the first embodiment is suitable for use in cerebral blood vessels with a small bending radius.

[0051] By deploying the stent 1 of the first embodiment at a lesion site in the lumen of a blood vessel, the lumen of the blood vessel is expanded, ensuring patency of the lesion site. By removing (retrieving) the stent 1 from the lumen of the blood vessel after a predetermined period of time has passed, complications caused by the indwelling stent, such as restenosis, re-occlusion, and thrombosis, can be prevented. Furthermore, the stent 1 of the first embodiment has excellent shape-following properties, and therefore is highly protective of the blood vessel. Note that the stent 1 of the first embodiment can be used not only for the treatment of blood vessels, but also for the treatment of luminal structures in general, such as the esophagus and large intestine.

[0052] The stent 1 of the first embodiment can also be used to treat cerebral vasospasm. Note that the stents of other embodiments described below also exhibit the same effects as the stent 1 of the first embodiment.

[0053] (Second embodiment) The stent 1 of the second embodiment differs from the first embodiment in the rotation suppression structure provided on the antenna portion 4. The other configurations of the stent 1 of the second embodiment are the same as those of the first embodiment. Therefore, in the second embodiment, only the different parts are illustrated, and the entire stent 1 is not illustrated. Furthermore, in the description and drawings of the second embodiment, the same reference numerals as in the first embodiment are used for components and the like that are equivalent to those in the first embodiment, and redundant explanations will be omitted.

[0054] FIG. 10A is a side view schematically illustrating the connection between the stent 1 and the pusher wire 2 and the rotation suppression structure provided on the antenna portion 4. In FIG. 10A, the mesh pattern structure of the struts 11 and 21 connected to the pusher wire 2 is appropriately simplified to facilitate understanding of the rotation suppression structure of the second embodiment. Similar to FIG. 1, FIG. 10A illustrates the shape of the stent 1 in its natural state. Furthermore, FIG. 10B is a cross-sectional view taken along line s4-s4 in FIG. 10A. FIG. 10C is a cross-sectional view taken along line s5-s5 in FIG. 10A. Although the circumferential direction OD shown in FIG. 10C does not strictly coincide with the circumferential direction OD shown in FIG. 10A, the present specification will be described assuming that the circumferential direction OD shown in FIG. 10C is generally the same direction as the circumferential direction OD shown in FIG. 10A.

[0055] First, the connection between the stent 1 and the pusher wire 2 will be described. As shown in Fig. 10A , an end 102a on the proximal side LD1 of the first stent main body 10 (first antenna portion 102) is connected to the distal side LD2 of the pusher wire 2 at a connection portion J10. Furthermore, an end 202a on the proximal side LD1 of the second stent main body 20 (second antenna portion 202) is connected to the distal side LD2 of the pusher wire 2 at a connection portion J20. Fig. 10A shows an example in which the connection portion J10 of the first stent main body 10 and the connection portion J20 of the second stent main body 20 are formed at the same position in the axial direction LD of the pusher wire 2, but the positions of the respective connection portions may be different in the axial direction LD of the pusher wire 2. 10A , the connection portions J10 of the first stent body 10 and the connection portions J20 of the second stent body 20 are shown schematically, showing the positions and ranges where they are connected by welding or the like. As shown in Fig. 10B , the connection portions J10 of the first stent body 10 and the connection portions J20 of the second stent body 20 are formed at equal intervals in the circumferential direction of the pusher wire 2. The intervals at which the connection portions are formed in the circumferential direction of the pusher wire 2 are not limited to the example shown in Fig. 10B and may be set as appropriate. The number of end portions 102 a on the proximal side LD1 of the first stent body 10 and the number of end portions 202 a on the proximal side LD1 of the second stent body 20 are not limited to the above example.

[0056] Next, we will explain the rotation suppression structure provided in the antenna portion 4. As shown in Figure 10A, the stent 1 of the second embodiment has, as a rotation suppression structure, an inverse intersection portion 25 in which some struts 11 of the first antenna portion 102 and some struts 21 of the second antenna portion 202 are arranged so that their radial positions are interchanged and are configured to be able to abut against each other in the circumferential direction OD. Here, "abutting" means, for example, contacting in an abutting manner.

[0057] The remaining struts 11 of the first antenna unit 102 and struts 21 of the second antenna unit 202 form intersections 26, as shown in Figure 10A. At the intersections 26, the struts 11 and 21 do not swap their radial positions, so they do not abut against each other in the circumferential direction OD. Figure 10A shows an example in which reverse intersections 25 and intersections 26 are alternately provided in the circumferential direction OD. By providing the antenna unit 4 with reverse intersections 25 as shown in Figure 10A, relative rotation about the central axis of the first antenna unit 102 and the second antenna unit 202 can be suppressed.

[0058] As shown in Figure 10C , at the reverse intersection 25 (rotation suppression structure), the struts 11 of the first antenna portion 102 and the struts 21 of the second antenna portion 202 are in contact with each other and overlap in the radial direction RD, but are not in contact with each other in the circumferential direction OD. In the state shown in Figure 10C , the struts 11 of the first antenna portion 102 and the struts 21 of the second antenna portion 202 do not necessarily have to be in contact with each other in the radial direction RD. In a stent 1 having a reverse intersection 25, repeated radial contraction and expansion can cause the first antenna portion 102 and the second antenna portion 202 to rotate relatively around the central axis. When the struts 11 and 21 that intersect at the reverse intersection 25 rotate relatively in the circumferential direction, the struts come into contact with each other in the circumferential direction, pressing against each other. 10C shows, as an example, how the strut 21 of the second antenna unit 202 moves in the circumferential direction OD (OD1-OD2) relative to the strut 11 of the first antenna unit 102. As shown in FIG. 10C , when the strut 21 moves in the circumferential direction OD1 (to the right in the figure), the struts 11 and 21 come into contact with each other in a region a1, pressing against each other. When the strut 21 moves in the circumferential direction OD2 (to the left in the figure), the struts 11 and 21 come into contact with each other in a region a2, pressing against each other. Although not shown, the same applies when the struts 11 of the first antenna unit 102 move in the circumferential direction OD (OD1-OD2) relative to the struts 21 of the second antenna unit 202, and when the struts 11 of the first antenna unit 102 and the struts 21 of the second antenna unit 202 move relative to each other in the circumferential direction OD (OD1-OD2). In this way, the two struts abut against each other in the circumferential direction so as to press against each other, thereby restricting the two struts from rotating (moving) relative to each other in the circumferential direction. Therefore, the relative rotation about the central axis of the first main body unit 101, which is formed integrally with the first antenna unit 102, and the second main body unit 201, which is formed integrally with the second antenna unit 202, is restricted.Therefore, the intersection portion 24 of the inner cell 22 of the second stent body 20 can be maintained in the opening portion 13 of the outer cell 12 of the first stent body 10 (see Figure 3C), so the increased surface area can be more appropriately maintained.

[0059] 10C , the struts 11 of the first antenna unit 102 and the struts 21 of the second antenna unit 202 may be in abutment with each other in the circumferential direction beforehand, so as to press against each other. That is, the struts 11 and 21 that intersect at the reverse intersection 25 may be in abutment with each other in the circumferential direction before they rotate relative to each other about the central axis, or, as described above, may be configured so that the struts are in abutment with each other in the circumferential direction when they rotate relative to each other about the central axis. Furthermore, the reverse intersection 25 (rotation suppression structure) may be provided at least at one location in the circumferential direction of the antenna unit 4.

[0060] FIG. 11 is a development view schematically illustrating another embodiment of a rotation suppression structure provided in the antenna unit 4. The antenna unit 4 of this embodiment has a Y-shaped branched connection portion 104 on the proximal side LD1 of the first antenna unit 102. The connection portion 104 is formed by a strut 11 located on the proximal-most side LD1 of the first antenna unit 102 and two struts 11 connected in a V-shape on the distal side LD2 of the strut 11. In the first antenna unit 102 illustrated in FIG. 11 , the connection portion 104 is formed at two locations in the circumferential direction OD. The antenna unit 4 also has a Y-shaped branched connection portion 204 on the proximal side LD1 of the second antenna unit 202. The connection portion 204 is formed by a strut 21 located on the proximal-most side LD1 of the second antenna unit 202 and two struts 21 connected in a V-shape on the distal side LD2 of the strut 21. In the second antenna part 202 illustrated in FIG. 11, the connection parts 204 are formed at two locations in the circumferential direction OD.

[0061] As described above, the stent 1 is fabricated by inserting the second stent body 20, which has been reduced in diameter, into the first stent body 10 (see FIG. 6 ). After inserting the second stent body 20 into the first stent body 10, as shown in FIG. 11 , the connecting portion 204 of the second antenna unit 202, which is located on the inside in the radial direction, is passed outside the connecting portion 104 of the first antenna unit 102. Furthermore, on the proximal side LD1 of the antenna unit 4, the connecting portion 204 of the second antenna unit 202 is passed inside the connecting portion 104 of the first antenna unit 102. By performing these operations for the two connecting portions 204 of the second antenna unit 202, the two struts 21 (second antenna unit 202) connected in a V-shape are caught on the outside of the Y-shaped portion (first antenna unit 102) formed by the two outer struts 11 connected in a V-shape and the end portions 102 a, thereby forming two reverse intersections 25 along the circumferential direction OD of the antenna unit 4. Thereafter, as shown in Figures 10A and 10B, the end 102a of the proximal side LD1 of the first antenna portion 102 and the end 202a of the proximal side LD1 of the second antenna portion 202 are connected to the distal side LD2 of the pusher wire 2, thereby obtaining a stent having a rotation suppression structure formed in the antenna portion 4.

[0062] (Third Embodiment) The stent system of the third embodiment differs from the first embodiment in that it includes a separate antenna portion on the distal side of the stent. The other configurations of the stent system of the third embodiment are the same as those of the first embodiment. Therefore, in the third embodiment, only the different configurations are illustrated, and the common configurations are not illustrated. Furthermore, in the description and drawings of the third embodiment, the same reference numerals as those of the first embodiment are used for components and the like that are equivalent to those of the first embodiment, and redundant explanations are omitted.

[0063] Fig. 12 is a side view of a stent system 100A according to the third embodiment. Fig. 13A is a side view of a first stent body 10 in the third embodiment. Fig. 13B is a side view of a second stent body 20 in the third embodiment. As shown in Fig. 12, the stent system 100A of the third embodiment comprises a stent 1A and a pusher wire 2. The stent 1A comprises a main body portion 3, a proximal antenna portion 4, and a distal antenna portion 5. In the stent 1A of the third embodiment, the proximal antenna portion 4 is substantially the same as the antenna portion 4 in the stent 1 of the first embodiment, and is therefore designated by the same reference numeral.

[0064] The distal antenna section 5 is a section that converges the distal side LD2 of the main body section 3 to the proximal side LD1 of the distal end shaft 6 (described later) and is formed integrally with the main body section 3 in the axial direction. The distal antenna section 5 is composed of a third antenna section 103 (described later) of the first stent body 10 and a fourth antenna section 203 (described later) of the second stent body 20. The distal antenna section 5 has a mesh pattern structure similar to the main body section 3, but the cells that form the distal antenna section 5 are designed not to support the inner wall of the blood vessel when expanded within the blood vessel. The distal side LD2 of the distal antenna section 5 is connected to the proximal side LD1 of the distal end shaft 6. In FIG. 12 , the connection portion between the distal antenna section 5 and the distal end shaft 6 is not shown. The distal end shaft 6 is a mark for identifying the position of the distal side LD2 of the stent 1A in an X-ray image, and at least a portion of the distal end shaft 6 is made of a radiopaque material. The connection between the distal side antenna portion 5 of the stent 1A and the distal end shaft 6 may be the same as the connection between the stent 1 and the pusher wire 2 described above (see FIG. 10A ). That is, the distal side LD2 of the first stent main body 10 (third antenna portion 103), the distal side LD2 of the second stent main body 20 (fourth antenna portion 203), and the proximal side LD1 of the distal end shaft 6 are connected directly or indirectly.

[0065] The main body portion 3 is a portion that dilates a narrowed portion of a biological lumen and includes a first stent body (first cylindrical portion) 10 and a second stent body (second cylindrical portion) 20. As shown in Fig. 13A, the first stent body 10 of the third embodiment includes a first main body portion 101, a first antenna portion 102, and a third antenna portion 103. The third antenna portion 103 converges the proximal side LD1 of the first main body portion 101 toward the distal side LD2 of the distal end shaft 6, and gradually reduces in diameter from the end of the proximal side LD1 of the first main body portion 101 toward the distal side LD2 of the distal end shaft 6. The configuration of the third antenna portion 103 is substantially the same as that of the first antenna portion 102, except that the direction of diameter reduction is from the proximal side LD1 to the distal side LD2.

[0066] 13B , the second stent body 20 of the third embodiment includes a second main body portion 201, a second antenna portion 202, and a fourth antenna portion 203. The fourth antenna portion 203 is a portion that converges the proximal side LD1 of the second main body portion 201 toward the distal side LD2 of the distal end shaft 6, and is gradually reduced in diameter from the end of the proximal side LD1 of the first main body portion 101 toward the distal side LD2 of the distal end shaft 6. The configuration of the fourth antenna portion 203 is substantially the same as that of the second antenna portion 202, except that the direction of diameter reduction is from the proximal side LD1 to the distal side LD2.

[0067] Although not shown in Fig. 12, in the stent 1A of the third embodiment, the proximal antenna portion 4 and the distal antenna portion 5 are provided with a rotation suppression structure. The structures described in the first and / or second embodiments can be applied as the rotation suppression structure. It is sufficient that the rotation suppression structure is provided at least in the proximal antenna portion 4, and it is more preferable that the rotation suppression structure is also provided in the distal antenna portion 5. When the rotation suppression structure is provided in the proximal antenna portion 4 and the distal antenna portion 5 of the stent 1A, the respective rotation suppression structures may be the same or different.

[0068] Like the stent 1 of the first embodiment, the stent 1A of the third embodiment has a large surface area and excellent shape-conforming ability to the vascular structure and diameter reduction ability. Furthermore, the stent 1A of the third embodiment is provided with a rotation suppression structure, which allows the increased surface area to be more appropriately maintained. In particular, the stent 1A of the third embodiment includes antenna portions on the proximal and distal sides of the main body portion 3, and by providing a rotation suppression structure on each of these two antenna portions, the relative rotation of the first stent body 10 and the second stent body 20 about the central axis can be more effectively suppressed.

[0069] (Method of Use) Next, an example of a method of using the stents 1, 1A of each embodiment will be described. Here, the stent 1 of the first embodiment will be described, but the same applies to the stent 1A of the other embodiments. Figures 14A to 14D are schematic diagrams showing the procedure for dilating a stenotic site in a blood vessel using the stent 1. Figures 14C and 14D show a simplified shape of the stent 1. Here, a procedure for widening a stenotic site CS formed in a blood vessel BV to ensure blood flow will be described. Note that the following procedure is performed while the position of the stent, etc., is grasped using a visible marker (radiopaque marker).

[0070] First, as shown in Fig. 14A, a guidewire 40 is passed through the stenosis site CS. A catheter 50 is fitted onto the guidewire 40. Next, as shown in Fig. 14B, the tip of the catheter 50 fitted onto the guidewire 40 is inserted into the stenosis site CS along the passed guidewire 40 and passed through until it reaches the distal LD2 side of the stenosis site CS. Next, although not shown, the guidewire 40 is pulled out of the living body and recovered from the catheter 50. Then, a stent 1 is inserted from the proximal LD1 side of the catheter 50. The stent 1 is inserted into the catheter 50 in a contracted state.

[0071] Next, as shown in Figure 14C, the stent 1 is deployed from the tip of the catheter 50 on the distal LD2 side of the stenosis site CS. The tip of the catheter 50 is positioned on the distal LD2 side of the stenosis site CS, and the catheter 50 is retracted toward the proximal LD1 side, thereby deploying the stent 1 from the tip of the catheter 50. When the stent 1 is deployed from the tip of the catheter 50, the stent 1 expands by its own expansion force, thereby pushing open the stenosis site CS from the inside. By pushing open the stenosis site CS from the inside with the expanded stent 1, blood flow in the blood vessel BV can be ensured.

[0072] After it is confirmed that blood flow in the blood vessel BV is ensured, follow-up observation is performed for, for example, about 5 to 60 minutes. After follow-up observation, as shown in Figure 14D, the tip of the catheter 50 is advanced toward the distal end LD2 of the stent 1, and the entire stent 1 is retracted into the catheter 50. This allows the stent 1 and the catheter 50 to be retrieved outside the body.

[0073] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and variations, such as those described below, are possible, and are also within the technical scope of the present invention. Furthermore, the effects described in the embodiments are merely a list of the most preferable effects resulting from the present invention, and are not limited to those described in the embodiments. Note that the above-described embodiments and the modifications described below can also be used in appropriate combinations, but detailed description thereof will be omitted.

[0074] (Modification) In the rotation suppression structure of the first embodiment, either a joint 15 (see FIG. 9A) or a joint 16 (see FIG. 9B) may be provided in the portion where struts 11 and 21 overlap in the radial direction.

[0075] A structure may be adopted that combines the rotation suppression structure (joints 15, 16) of the first embodiment with the rotation suppression structure (reverse intersection 25) of the second embodiment. For example, at the reverse intersection 25 of the second embodiment, struts that are radially interchanged may be joined by welding or the like. Furthermore, at a portion other than the reverse intersection 25, struts that overlap in the radial direction may be joined by welding or the like.

[0076] In a structure in which struts are not joined by welding or the like, such as the rotation prevention structure (reverse intersection portion 25) of the second embodiment, the stent material may be a metal material or other material. For example, the stent material may be a synthetic resin material such as polyolefins such as PE and PP, polyamide, polyvinyl chloride, polyphenylene sulfide, polycarbonate, polyether, or polymethyl methacrylate. Biodegradable resins (biodegradable polymers) such as polylactic acid (PLA), polyhydroxybutyrate (PHB), polyglycolic acid (PGA), and polyε-caprolactone may also be used. When the reverse intersection portion 25 of the second embodiment is used as the rotation prevention structure of a stent, one of the stent bodies of the first antenna portion 102 and the second antenna portion 202 may be formed of a metal material, and the other stent body may be formed of a resin material.

[0077] The stent 1 (1A) is used in applications where it is temporarily placed in a blood vessel and then retrieved outside the body, but it can also be used in applications where the stent 1 (1A) remains in the blood vessel without being retrieved from the body. When used in such applications, for example, the connection portion between the stent 1 (1A) and the pusher wire 2 may be configured with a heater coil, filament, etc., so that the connection portion is cut (melted) when electricity is applied to the pusher wire 2. Also, the connection portion between the stent 1 (1A) and the pusher wire 2 may be configured so that it is mechanically cut when a rotational force is applied to the pusher wire 2 in the circumferential direction. The connection portion between the stent 1 (1A) and the pusher wire 2 is not limited to the above example, and may have any configuration as long as the stent 1 (1A) and the pusher wire 2 can be separated by the operator's operation.

[0078] DESCRIPTION OF SYMBOLS 1, 1A Stent 2 Pusher wire 3 Main body portion 4 Antenna portion / proximal antenna portion 5 Distal antenna portion 6 Distal end shaft 10, 10A First stent main body 11, 21 Strut 12 Outer cell 13 Opening portion 14 Intersection portion 15, 16 Junction portion (rotation suppression structure) 20, 20A Second stent main body 22 Inner cell 23 Opening portion 24 Intersection portion 25 Reverse intersection portion (rotation suppression structure) 100, 100A Stent system 101 First main body portion 102 First antenna portion 103 Third antenna portion 201 Second main body portion 202 Second antenna portion 203 Fourth antenna portion

Claims

1. A stent having a double - structure cylindrical portion used for expanding a stenotic portion of a biological lumen, wherein the cylindrical portion includes: a first cylindrical portion in which a plurality of first cells are arranged in the circumferential direction and the central axis direction; a second cylindrical portion in which a plurality of second cells are arranged in the circumferential direction and the central axis direction, and at least a region for expanding the stenotic portion of the biological lumen is inserted into the first cylindrical portion. In a state where at least a region for expanding the stenotic portion of the biological lumen of the second cylindrical portion is inserted into the first cylindrical portion, an overlapping portion of the second cells is arranged at an opening portion of the first cells. The proximal side of the first cylindrical portion, the proximal side of the second cylindrical portion, and the distal side of the pusher wire are directly or indirectly connected. A first antenna portion provided between an end portion on the proximal side of the first cylindrical portion and a region for expanding the stenotic portion of the biological lumen, and a second antenna portion provided between an end portion on the proximal side of the second cylindrical portion and a region for expanding the stenotic portion of the biological lumen are provided with a rotation - suppressing structure for suppressing relative rotation around the central axis of the first antenna portion and the second antenna portion.

2. The stent according to claim 1, wherein the distal side of the first cylindrical portion, the distal side of the second cylindrical portion, and the proximal side of the distal - end shaft are directly or indirectly connected.

3. The stent according to claim 1 or 2, wherein in the rotation - suppressing structure, a part of the first antenna portion and the second antenna portion are joined to each other.

4. The stent according to claim 1 or 2, wherein in the rotation - suppressing structure, at least a part of the first antenna portion and the second antenna portion are arranged such that their radial positions are interchanged and are configured to be in contact with each other in the circumferential direction.

5. The stent according to any one of claims 1 or 2, wherein in a state where at least a region for expanding the stenotic portion of the biological lumen of the second cylindrical portion is inserted into the first cylindrical portion, the second cylindrical portion presses the first cylindrical portion outward in the radial direction.

6. The stent according to any one of claims 1 or 2, which is used for a purpose of being temporarily placed in a biological lumen and then retrieved outside the body.

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