In vivo placement stent and stent delivery system

Abstract

A stent 1 has: a plurality of annular bodies 2 each formed from a linear component; and connection parts. The connection parts are based on a first pattern connection part 3 for connecting an apex 25 on one end side and a connection linear section 23 or 24 closer to the one end than the apex on the one end side or a second pattern connection part 4 for connecting a connection linear section and a connection linear section closer to the other end than the former connection linear section, and other connection parts are of one type of a first or second pattern connection part which is not selected, a third pattern connection part 5 for connecting an apex 26 on the other end side and a connection linear section closer to the other end than the apex on the other end side, and a fourth pattern connection part 6, 7 for connecting an apex on the one end side and an apex on the other end side positioned closer to the one end than the apex on the one end side. The number of connection parts between adjacent annular bodies is equal to or larger or smaller by 1 than the number of one end-side apexes or other end-side apexes of the connected annular body.

Description

[Technical Field]

[0001] The present invention relates to a stent for placement in a living body and a stent delivery system used to improve strictures or obstructions occurring in biological lumens such as blood vessels, bile ducts, tracheas, esophagus, and urethra. [Background technology]

[0002] Stents for placement in vivo are used to treat various diseases caused by narrowing or occlusion of blood vessels or other lumens in the body. Stents are formed in a tubular shape to expand the narrowed or occluded site and secure the lumen. A stent is inserted into the body from outside, and therefore has a small diameter when inserted. It expands at the target stenosis or occlusion site to increase its diameter and maintain the lumen intact. Stents are generally cylindrical metal wires or tubes that are thinned and attached to catheters, inserted into the body, and expanded at the target site by some method, adhering to and fixing to the inner wall of the lumen to maintain the lumen shape.

[0003] Stents are divided into self-expanding stents and balloon-expandable stents based on their function and placement method. Balloon-expandable stents do not have any expansion capabilities themselves; instead, the stent is mounted on a balloon and inserted into the target site. The balloon is then inflated, and the stent expands (plastically deforms) due to the balloon's expansion force, adhering and fixing it to the inner surface of the target lumen. This type of stent requires the stent expansion process described above. On the other hand, self-expanding stents have their own expansion capabilities; they are inserted into the body in a narrow, contracted state, and when released at the target site, they return to their original expanded state, adhering and fixing it to the inner wall of the lumen, maintaining the lumen shape.

[0004] One of the causes of ischemic cerebral arterial disease is stenosis or occlusion of intracranial arteries. Antiplatelet therapy is a common treatment method, and risk can be reduced. However, medical treatment has its limitations, and patients who are resistant to medication are treated with balloon dilatation or stent placement. Stent placement is associated with a high incidence of perioperative complications, one of the contributing factors being intra-stent thrombus formation. The blood-brain barrier is known to limit drug delivery to the brain, making it an environment prone to complications due to intra-stent thrombus formation, even with continued antithrombotic therapy after surgery.

[0005] Furthermore, intracranial blood vessels often have complex, tortuous sections. When a stent is placed in a curved area, a stent with poor tracking ability can buckle, causing the stent struts to intrude into the blood vessel lumen, obstructing blood flow and leading to thrombosis. Furthermore, the stent struts can damage the blood vessel wall, potentially causing perforation or injury. To reduce the risk of in-stent thrombosis, stents must be designed to ensure tracking ability without damaging the blood vessel.

[0006] As a self-expanding stent, the one shown in Japanese Patent Laid-Open Publication No. 2003-93519 (Patent Document 1) has been proposed.

[0007] The stent disclosed in Patent Document 1 comprises a plurality of wavy struts extending axially from one end of the stent to the other and arranged circumferentially around the stent, and a plurality of connecting struts connecting adjacent wavy struts and extending in a predetermined longitudinal direction, with the ends of the wavy struts being joined to the ends of adjacent wavy struts. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2003-93519 A (US2002-193868A, US2004-138730A, US2006-149355A, EP1266640A) Summary of the Invention [Problem to be solved by the invention]

[0009] However, the stent disclosed in Patent Document 1 has wavy struts that extend in the axial direction from one end of the stent to the other and are arranged in a plurality in the circumferential direction of the stent. Through research by the present inventors, it was found that the stent disclosed in Patent Document 1 does not have sufficient expansive force and tracking ability because the wavy struts extend in the axial direction.

[0010] Therefore, an object of the present invention is to provide a tubular stent for placement in a living body, in which a plurality of annular bodies formed by wavy and annular linear elements each having a plurality of one-end vertices at one axial end and a plurality of other-end vertices at the other axial end of the stent are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, and which has good storability and followability due to radial compression and sufficient expansion force, and a stent delivery system for placement in a living body. [Means for solving the problem]

[0011] The above objectives are achieved by the following: A stent for placement in vivo, in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in an axial direction, and adjacent annular bodies are connected by a connecting portion, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of the connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end side vertex and the connecting linear portion located on the one end side of the one end side vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are basic pattern connecting portions that are not selected in the basic pattern connecting portions. a third pattern connecting portion connecting the one end vertex to the connecting linear portion located on the other end side of the one end vertex; and a fourth pattern connecting portion connecting the one end vertex to the other end vertex located on the one end side of the one end vertex, and further, the number of connecting portions connecting adjacent annular bodies located in the central portion is the same as the number of the one end vertices or the other end vertices of the annular bodies connected by the connecting portions, or is one more or one less.

[0012] The above objectives are also achieved by the following: A stent delivery system comprising a sheath, the stent housed within the distal end of the sheath, and a shaft for inserting through the sheath and releasing the stent from the distal end of the sheath, wherein the stent is formed in a roughly cylindrical shape, is compressed in the direction of its central axis when inserted into a living body, and expands outward and restores to its pre-compression shape when placed in the living body. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a development view of a stent for placement in a living body according to one embodiment of the present invention during production. [Figure 2] FIG. 2 is a partially enlarged view of the in-vivo stent of FIG. [Figure 3] FIG. 3 is a development view of a stent for placement in a living body according to another embodiment of the present invention during production. [Figure 4] FIG. 4 is a partially enlarged view of the in-vivo stent of FIG. [Figure 5] FIG. 5 is a development view of a stent for placement in a living body according to another embodiment of the present invention during production. [Figure 6] FIG. 6 is a partially enlarged view of the in-vivo stent of FIG. [Figure 7] FIG. 7 is a development view of a stent for placement in a living body according to another embodiment of the present invention during production. [Figure 8] FIG. 8 is a partially enlarged view of the in-vivo stent of FIG. [Figure 9] FIG. 9 is a development view of a stent for placement in a living body according to another embodiment of the present invention during production. [Figure 10] FIG. 10 is a partially enlarged view of the in-vivo stent of FIG. [Figure 11] FIG. 11 is a front view of a stent delivery system according to an embodiment of the present invention. [Figure 12] FIG. 12 is an enlarged, partially cutaway view of the distal end portion of the stent delivery system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] The in-vivo stent of the present invention will be described with reference to the examples shown in the drawings. 1 and 2, the stent 1 for placement in vivo of the present invention is a stent for placement in vivo in which a plurality of annular bodies 2 formed in an annular shape by a single endless linear element (strut) are arranged in the axial direction, and adjacent annular bodies 2 (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2m) are connected by connecting portions 3, 8. In Figs. 1 and 2, the left side is referred to as "one end" and the right side is referred to as "the other end." The annular body 2 (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2m) is formed by a single endless linear element having a plurality of one-end vertices 25 (one-end bends) located on one end side of the stent in the axial direction, a plurality of other-end vertices 26 (other-end bends) located on the other end side of the stent in the axial direction, and a plurality of connecting linear portions 23, 24 connecting the one-end vertices 25 and the other-end vertices 26.

[0015] Adjacent sets of annular bodies 2 located at least in the central portion of the stent are connected by a plurality of connecting portions. Furthermore, 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions made up of first pattern connecting portions 3 connecting one end vertex 25 to a connecting linear portion 23 or 24 located on the one end side of this one end vertex 25, or second pattern connecting portions 4 connecting a connecting linear portion 23 or 24 to a connecting linear portion 23 or 24 located on the other end side of the connecting linear portion 23 or 24. Furthermore, the remaining connecting portions located in the central portion are at least one type of pattern connecting portion selected from the first pattern connecting portion 3 or the second pattern connecting portion 4 that was not selected in the basic pattern connecting portion, the third pattern connecting portion 5 that connects the other end side vertex 26 to the connecting line portion 23 or 24 located on the other end side of the other end side vertex 26, and the fourth pattern connecting portions 6, 7 that connect the one end side vertex 25 to the other end side vertex 26 located on the one end side of the one end side vertex 25. Furthermore, the number of connectors connecting adjacent central annular bodies 2 is the same as, or one more than, the number of vertices on one end or the number of vertices on the other end of the annular bodies connected by the connectors. Preferably, the number of connectors is the same as the number of vertices on one end or the number of vertices on the other end of the annular bodies connected by the connectors. Note that "one more than the number of vertices on one end or the number of vertices on the other end" refers to a state in which a connector is added between adjacent connectors in the circumferential direction of any stent. The added connector pattern may be any of the connector patterns described above. Furthermore, "one less than the number of vertices on one end or the number of vertices on the other end" refers to a state in which one connector is removed from the number of adjacent central annular bodies 2 in each embodiment shown in the figures. This stent 1 can be effectively used as a stent for dilating cerebral arteries (a stent for treating cerebral artery stenosis).

[0016] The stent 1 of this embodiment is formed in a substantially cylindrical shape, is compressed in the direction of its central axis when inserted into the body, and is a so-called self-expanding stent that expands outward and restores its shape before compression when placed in the body. As shown in FIGS. 1 and 2 , the stent 1 of this embodiment has a configuration in which a plurality of annular bodies 2 (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, and 2m) are arranged in parallel in the axial direction so that adjacent annular bodies are connected to each other. Each annular body 2 (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, and 2m) is formed of a wavy, annular linear element having a plurality of one-end bent portions with vertices 25 at one axial end and a plurality of other-end bent portions with vertices 26 at the other axial end of the stent 1. The one-end bent portions and the other-end bent portions are connected by connecting linear portions 23 and 24. In the stent of this embodiment, the connecting linear portions 23 and 24 have a substantially straight or gently curved shape. The number of ring-shaped bodies 2 in the stent of the present invention is preferably 4 to 100, and particularly preferably 6 to 80. The number of ring-shaped bodies 2 in stents 1 to 1d is 12 or 14.

[0017] As shown in Fig. 1, the annular bodies 2 (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2m) in the stent 1 of this embodiment have a plurality of one-end vertices 25 and other-end vertices 26 arranged at approximately the same pitch. The number of one-end vertices 25 and other-end vertices 26 in one annular body of the stent of the present invention is preferably 4 to 12, and more preferably 4 to 10.

[0018] First, the stent 1 of the embodiment shown in FIGS. 1 and 2 will be described. In the stent 1 of this embodiment, as shown in Figures 1 and 2, the basic pattern between adjacent pairs of annular bodies 2 (2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k) located in the central portion is a first pattern connecting portion 3 (3a, 3b) that connects one end side vertex 25 (e.g., 25f, 25g) to a connecting linear portion 23 or 24 (e.g., 23e, 24f) located on the one end side of the one end side vertex 25 (e.g., 25f, 25g), and further, between the annular bodies connected by the first pattern connecting portion 3 (3a, 3b), there is provided a third pattern connecting portion 5 (5a, 5b) that connects the other end side vertex 26 (e.g., 26e, 26f) to a connecting linear portion 23 or 24 (e.g., 23f, 24g) located on the other end side of the other end side vertex 26 (e.g., 26e, 26f).

[0019] The advantages of the first pattern connecting portion 3 and the third pattern connecting portion 5 are that they suppress buckling in curved blood vessels and enable the stent to follow the blood vessel while maintaining the lumen. The connecting portions connected to the connecting linear portions 23 and 24 can deform so that the axial compressive force applied to the stent at the curved portion of the blood vessel acts in a rotational direction, thereby suppressing buckling.

[0020] Generally, when a stent is placed in a bent section, an axial compressive force is applied to the inside of the bend, causing adjacent annular members to move closer together. This force is transmitted to the connectors connecting the annular members, deforming the stent. However, if the force cannot be alleviated by deformation of the connectors and surrounding struts alone, the stent will buckle, causing significant deformation. When buckling occurs, the stent will intrude into the blood vessel lumen, making it impossible to maintain the blood vessel diameter in that area and creating a breeding ground for thrombus formation. If the connecting part is the vertex, the compressive force caused by placing the bent part acts in the axial direction, but if the connecting part is the connecting linear part, the compressive force changes from the axial direction to the rotational direction, thereby suppressing buckling.

[0021] In the stent 1 of this embodiment, all adjacent annular bodies located in the central portion are connected by a first pattern connecting portion 3 that connects the one end side vertex 25 to a connecting linear portion 23 or 24 located on the one end side of the one end side vertex 25, and a third pattern connecting portion 5 that connects the other end side vertex 26 to a connecting linear portion 23 or 24 located on the other end side of the other end side vertex 26, and the first pattern connecting portions 3 and the third pattern connecting portions 5 are arranged alternately in the circumferential direction between adjacent annular bodies.

[0022] In the stent 1 of this embodiment, adjacent pairs of annular bodies 2 (2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k) located in the central portion are connected only by first pattern connecting portions 3 (3a, 3b) and third pattern connecting portions 5 (5a, 5b). Therefore, the proportions of the first pattern connecting portions 3 (3a, 3b) and the third pattern connecting portions 5 (5a, 5b) are each 50%. As in this embodiment, it is preferable that adjacent annular bodies 2 located in the central portion are connected by connecting portions of different patterns.

[0023] In the stent 1 of this embodiment, the first pattern connecting portions 3 (3a, 3b) and the third pattern connecting portions 5 (5a, 5b) are arranged alternately in the circumferential direction, and the inclination directions of each are the same. In addition, it is preferable that adjacent connecting portions in the axial direction of the stent in all adjacent annular bodies located in the central portion have different circumferential directions in which the connecting portions extend.Furthermore, it is preferable that adjacent connecting portions of the same pattern in the axial direction of the stent located in the central portion have different circumferential directions in which the connecting portions extend.

[0024] In the stent 1 of this embodiment, the first pattern connection portions 3a and 3b adjacent to each other in the axial direction of the stent 1 have different inclination directions, and similarly, the third pattern connection portions 5a and 5b adjacent to each other in the axial direction of the stent 1 also have different inclination directions. Furthermore, in the stent 1 of this embodiment, the first pattern connection portions 3 (3a, 3b) and the third pattern connection portions 5 (5a, 5b) have approximately the same axial length.

[0025] Furthermore, in the stent 1 of this embodiment, one end of the first pattern connecting portion 3 (3a, 3b) is connected to the other end bent portion side (the other end apex side) of the connecting linear portion 23 or 24 (e.g., 23e, 24f). Specifically, it is connected to a position closer to the other end apex side than the center of the connecting linear portion 23 or 24 (e.g., 23e, 24f). Furthermore, the other end of the third pattern connecting portion 5 (5a, 5b) is connected to the one end bent portion side (the one end apex side) of the connecting linear portion 23 or 24 (e.g., 23f, 24g). Specifically, it is connected to a position closer to the one end apex side than the center of the connecting linear portion 23 or 24 (e.g., 23f, 24g).

[0026] In the stent 1 of this embodiment, the first pattern connecting portions 3a have one-end curved portions 31a that are curved in the direction opposite to the inclination direction of the connecting portions 3a (upward in connecting portions that slope downward to the right in FIG. 2). The apex of this curved portion 31a is close to the apex 26 on the other end side of the connecting linear portions to which the connecting portions 3a are connected. The first pattern connecting portions 3b have one-end curved portions 31b that are curved in the direction opposite to the inclination direction of the connecting portions (downward in connecting portions that slope upward to the right in FIG. 2). The apex of this curved portion 31b is close to the apex 26 on the other end side of the connecting linear portions to which the connecting portions 3b are connected.

[0027] In the stent 1 of this embodiment, the third pattern connecting portion 5a has an other-end curved portion 51a that is curved in the inclined direction of the connecting portion 5a (downward at the connecting portion that slopes downward to the right in FIG. 2). The apex of the other-end curved portion 51a of the third pattern connecting portion 5a is close to the apex 25 on one end side of the connecting linear portion to which the connecting portion 5a is connected. The third pattern connecting portion 5b also has an other-end curved portion 51b that curves in the inclined direction of the connecting portion 5b (upward in the connecting portion that slopes upward to the right in FIG. 2). The vertex of the other-end curved portion 51a of the third pattern connecting portion 5b is close to the vertex 25 on one end side of the connecting linear portion to which the connecting portion 5b is connected.

[0028] The stent 1 of this embodiment has multiple convex portions formed on the outer surface of the stent 1 by the outward protrusion of the intermediate portions of the first pattern connection portion 3 and the third pattern connection portion 5. Specifically, the first pattern connection portion 3 (3a, 3b) and the third pattern connection portion 5 (5a, 5b) protrude outward when the stent is expanded, forming convex portions on the outer surface of the stent whose protrusion amount increases from both ends of the first pattern connection portion 3 and the third pattern connection portion 5 toward the center. The height of the convex portions is preferably 50 μm or more. The distance between the convex portions in the axial direction is approximately the same as the distance between the vertices on one end of adjacent annular bodies (the distance between the vertices on the other end).

[0029] In the stent 1 of this embodiment, between adjacent annular bodies 2, the connecting linear portions 23 and 24 of one annular body 2, the connecting linear portions 23 and 24 of the other adjacent annular body 2, and the first pattern connecting portions 3 and third pattern connecting portions 5 adjacent in the circumferential direction are formed, and the approximately rectangular closed cells are inclined in the first circumferential direction (first direction) of the stent, and are arranged in parallel in the circumferential direction. Furthermore, adjacent to the approximately rectangular closed cells in the axial direction are approximately rectangular closed cells inclined in a second direction, which is the opposite direction to the first circumferential direction of the stent 1, and are arranged in parallel in the circumferential direction. Furthermore, in the stent 1 of this embodiment, one end of the approximately rectangular closed cell inclined in the second direction is inserted into the recess between the other ends of the approximately rectangular closed cells inclined in the first direction. This provides good expansion retention.

[0030] 1, the stent 1 of this embodiment further comprises a one-end annular-body connecting portion 8 that connects the apex 26 of the other end of the annular body 2a located at one end to the apex 25 of the annular body 2b located at one end with the apex 26 of the adjacent annular body 2b, and an other-end annular-body connecting portion 8 that connects the apex 25 of the annular body 2m located at the other end to the apex 26 of the adjacent annular body 2k located at the other end with the apex 26 of the adjacent annular body 2m located at the other end. The connecting portion 8 has a shorter axial length than the connecting portions 3 and 5. Therefore, the stent 1 of this embodiment has so-called closed cells that are approximately diamond-shaped at both ends, and has high axial rigidity.

[0031] Next, a stent 1a according to an embodiment shown in FIGS. 3 and 4 will be described. In the stent 1a of this embodiment, the adjacent sets (first sets) of annular bodies 2 located in the central portion (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, between 2m and 2n) are connected, as shown in Figures 3 and 4, by a basic pattern of first pattern connecting portions 3 (3a, 3b) that connect one end vertex 25 (e.g., 25g, 25e) to connecting linear portions 23, 24 (e.g., 23f, 24d) located on the one end side of the one end vertex 25 (e.g., 25g, 25e), and further by third pattern connecting portions 5 (5a, 5b) that connect the other end vertex 26 (e.g., 26f, 26d) to connecting linear portions 23 or 24 (e.g., 23g, 24e) located on the other end side of the other end vertex 26 (e.g., 26f, 26d).

[0032] In the stent 1a of this embodiment, adjacent pairs of annular bodies located in the central portion (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, and between 2m and 2n) are connected only by first pattern connecting portions 3 (3a, 3b) and third pattern connecting portions 5 (5a, 5b). Therefore, among the above pairs of annular bodies, the proportion of first pattern connecting portions 3 (3a, 3b) and third pattern connecting portions 5 (5a, 5b) is 50% each. As in this embodiment, it is preferable that adjacent pairs of annular bodies 2 located in the central portion are connected by connecting portions of different patterns.

[0033] In the stent 1a of this embodiment, the first pattern connecting portions 3 (3a, 3b) and the third pattern connecting portions 5 (5a, 5b) are arranged alternately in the circumferential direction, and the inclination directions of each are the same. Furthermore, the first pattern connection portions 3a and 3b adjacent to each other in the axial direction of the stent 1a have different inclination directions, and similarly, the third pattern connection portions 5a and 5b adjacent to each other in the axial direction of the stent 1a also have different inclination directions. Furthermore, in the stent 1a of this example, the first pattern connection portions 3 (3a, 3b) and the third pattern connection portions 5 (5a, 5b) have approximately the same axial length.

[0034] Furthermore, in the stent 1a of this embodiment, as shown in Figures 3 and 4, the adjacent sets (first sets) of annular bodies 2 located in the central portion (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, and between 2m and 2n) of the multiple sets (second sets) of annular bodies 2 (between 2a and 2b, between 2c and 2d, between 2e and 2f, between 2g and 2h, between 2i and 2j, between 2k and 2m, and between 2n and 2p) are all connected by short fourth pattern connecting portions 6 (6a, 6b) that connect one end side vertex 25 (e.g., 25f, 25h) and the other end side vertex 26 (e.g., 26e, 26g). The apex-to-apex joints provide increased resistance to axial compression, facilitate stent release, and are less susceptible to shortening. In addition, they offer manufacturing advantages such as easier mounting.

[0035] In the stent 1a of this embodiment, the fourth pattern connecting portions 6 (6a, 6b) adjacent to each other in the circumferential direction of the stent are inclined in the same direction, while the fourth pattern connecting portions 6a and 6b adjacent to each other in the axial direction of the stent 1a are inclined in different directions. Furthermore, the fourth pattern connecting portions 6a and 6b have approximately the same axial length.

[0036] In the stent 1a of this embodiment, the fourth pattern connection portions 6 (6a, 6b) have a shorter axial length than the first pattern connection portions 3 (3a, 3b) and the third pattern connection portions 5 (5a, 5b). Therefore, the distances between the second set of annular bodies 2 (between 2a and 2b, between 2c and 2d, between 2e and 2f, between 2g and 2h, between 2i and 2j, between 2k and 2m, and between 2n and 2p) are shorter than the distances between the first set of annular bodies 2 (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, and between 2m and 2n).

[0037] In the stent 1a of this embodiment, the substantially rectangular closed cells inclined in the first circumferential direction (first direction) of the stent are also arranged in parallel in the circumferential direction. Furthermore, adjacent to the substantially rectangular closed cells in the axial direction are substantially rectangular closed cells inclined in a second direction, which is the opposite direction to the first circumferential direction of the stent 1a, also arranged in parallel in the circumferential direction. Furthermore, in the stent 1a of this embodiment, one end of the substantially rectangular closed cell inclined in the second direction is inserted into the recess between the other ends of the substantially rectangular closed cells inclined in the first direction. This provides expansion retention.

[0038] The stent 1a of this embodiment comprises a one-end annular body connecting portion that connects the other-end bent portion of the annular body located at one end with the one-end bent portion of the adjacent annular body, and a one-end annular body connecting portion that connects the one-end bent portion of the annular body located at the other end with the other-end bent portion of the adjacent annular body, and the one-end annular body connecting portion includes a fourth pattern connecting portion 6, and the other-end annular body connecting portion includes a fourth pattern connecting portion 6.

[0039] Specifically, in the stent 1a of this embodiment, as shown in Fig. 3, the vertex 26 on the other end side of the annular body 2a located at one end and the vertex 25 on one end side of the annular body 2b adjacent to the annular body 2a located at one end are connected by a fourth pattern connecting portion 6a. The vertex 25 on one end side of the annular body 2p located at the other end and the vertex 26 on the other end side of the annular body 2n adjacent to the annular body 2p located at the other end are connected by a fourth pattern connecting portion 6a. The axial length of the stent is shorter than that of connecting portion 3 and connecting portion 5. Therefore, the stent 1a of this embodiment has so-called closed cells that are approximately diamond-shaped at both ends, and has high axial rigidity.

[0040] Next, a stent 1b according to an embodiment shown in FIGS. 5 and 6 will be described. In the stent 1b of this embodiment, adjacent pairs of annular bodies 2 (2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k) located in the central portion are connected by second pattern connecting portions 4 (4a, 4b) that connect connecting linear portions 23, 24 (e.g., 23e, 24f) to connecting linear portions 23, 24 (e.g., 23f, 24g) located on the other end side of the connecting linear portions 23, 24 (e.g., 23e, 24f), and long fourth pattern connecting portions 7 (7a, 7b) that connect one end side vertices 25 (e.g., 25f, 25g) to other end side vertices 26 (e.g., 26e, 26f) located on the one end side of the one end side vertices 25 (e.g., 25f, 25g), as shown in Figures 5 and 6.

[0041] Since the second pattern connecting portion 4 (4a, 4b) connects the connecting linear portions, when the second pattern connecting portion 4 (4a, 4b) is placed at a bent portion of a blood vessel, the axial compressive force applied by the bent portion can be changed to act in a rotational direction, thereby suppressing buckling and providing good blood vessel tracking ability. The long fourth pattern connecting portions 7 (7a, 7b) connect adjacent vertices, so that when the stent is contracted, the connecting portions are sandwiched between the vertices, improving axial rigidity, making it easier to store in the sheath and release from the sheath, and making it less likely to shorten, i.e., the axial length of the stent becomes shorter, when the stent is expanded.

[0042] In the stent 1b of this embodiment, adjacent pairs of annular bodies 2 are connected only by the second pattern connection portions 4 (4a, 4b) and the fourth pattern connection portions 7 (7a, 7b). Furthermore, the second pattern connection portions 4 (4a, 4b) and the fourth pattern connection portions 7 (7a, 7b) are alternately arranged in the circumferential direction of the stent, and the inclination directions of each are the same. The second pattern connection portions 4a and 4b adjacent to each other in the axial direction of the stent 1b have different inclination directions. Similarly, the fourth pattern connection portions 7a and 7b adjacent to each other in the axial direction of the stent 1b also have different inclination directions. Furthermore, in the stent 1b of this embodiment, the second pattern connection portions 4 (4a, 4b) have a longer axial length than the fourth pattern connection portions 7 (7a, 7b).

[0043] Furthermore, in the stent 1b of this embodiment, one end of the second pattern connecting portion 4 (4a, 4b) is connected to the other end bent portion side of the connecting linear portion 23 or 24 (e.g., 23e, 24f). Specifically, one end of the second pattern connecting portion 4 (4a, 4b) is connected to a position closer to the other end vertex side than the center of the connecting linear portion 23 or 24 (e.g., 23e, 24f). Furthermore, the other end of the second pattern connecting portion 4 (4a, 4b) is connected to the one end bent portion side of the connecting linear portion 23 or 24 (e.g., 23f, 24g). Specifically, the other end of the second pattern connecting portion 4 (4a, 4b) is connected to a position closer to the one end vertex side than the center of the connecting linear portion 23 or 24 (e.g., 23f, 24g).

[0044] In addition, in stent 1b of this embodiment, second pattern connecting portions 4a include one-end curved portions 91a curved in the direction opposite to the inclination direction of the connecting portions (upward in the right-downward connecting portions in FIG. 6), and the other-end curved portions 91b curved in the inclination direction of the connecting portions (downward in the right-downward connecting portions in FIG. 6). Similarly, second pattern connecting portions 4b include one-end curved portions 92a curved in the direction opposite to the inclination direction of the connecting portions (downward in the right-upward connecting portions in FIG. 6), and the other-end curved portions 92b curved in the inclination direction of the connecting portions (upward in the right-upward connecting portions in FIG. 6). The apex of each curved portion is close to one-end vertex 25 or the other-end vertex 26 of the connecting linear portions connecting connecting portions 4 (4a, 4b).

[0045] Stent 1b of this embodiment has multiple protrusions extending from the outer surface of stent 1b. Specifically, second pattern connecting portions 4a and 4b protrude outward when the stent is expanded, forming protrusions on the outer surface of the stent whose protrusion amount increases from both ends of the connecting portions toward the center, and second pattern connecting portions 4a and 4b as a whole form protrusions. The protrusions formed by second pattern connecting portions 4a and 4b as a whole are most protruding at their center. The height of the protrusions is preferably 50 μm or more.

[0046] In stent 1b of this embodiment, substantially rectangular closed cells inclined in a first circumferential direction (first direction) of the stent are arranged in parallel in the circumferential direction. Furthermore, adjacent to the substantially rectangular closed cells in the axial direction are substantially rectangular closed cells inclined in a second direction, which is the opposite direction to the first circumferential direction of stent 1b, also arranged in parallel in the circumferential direction. Furthermore, in stent 1b of this embodiment, one end of a substantially rectangular closed cell inclined in the second direction is inserted into a recess between the other ends of the substantially rectangular closed cells inclined in the first direction. This provides expansion retention.

[0047] 5, the stent 1b of this embodiment includes a first-end annular-body connecting portion 8 that connects the vertex 26 of the annular body 2a located at one end to the vertex 25 of the annular body 2b located at one end with the vertex 26 of the annular body 2a located at one end, and an second-end annular-body connecting portion 8 that connects the vertex 25 of the annular body 2m located at the other end with the vertex 26 of the annular body 2k located at the other end with the vertex 25 of the annular body 2m located at the other end. The connecting portion 8 has a shorter axial length than the second pattern connecting portions 4 (4a, 4b) and the fourth pattern connecting portions 7 (7a, 7b). Therefore, the stent 1b of this embodiment has so-called closed cells that are approximately diamond-shaped at both ends, resulting in high axial rigidity.

[0048] Next, a stent 1c according to an embodiment shown in FIGS. 7 and 8 will be described. In the stent 1c of this embodiment, the adjacent sets of annular bodies 2 (2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k) located in the central portion are connected by a first pattern connecting portion 3 (3a, 3b) that uses a basic pattern to connect one end vertex 25 (e.g., 25f, 25g) to a connecting linear portion 23 or 24 (e.g., 23e, 24f) located on the one end side of the one end vertex 25 (e.g., 25f, 25g), as shown in Figures 7 and 8, and further by a long fourth pattern connecting portion 7 (7a, 7b) that connects the other end vertex 26 (e.g., 26e, 26f) to the one end vertex 25 (e.g., 25f, 25g) located on the other end side of the other end vertex 26 (e.g., 26e, 26f).

[0049] In the stent of the present invention, it is preferable that the number of connecting portions connecting adjacent ring bodies located in the central portion is the same as the number of vertices on one end side or the number of vertices on the other end side of the ring bodies connected by the connecting portion, or one more or one less. In the stent 1c of this embodiment, all adjacent annular bodies located in the central portion are connected by the first pattern connecting portion 3 (3a, 3b) or the fourth pattern connecting portion 7 (7a, 7b), and the first pattern connecting portion 3 and the fourth pattern connecting portion 7 are arranged alternately in the circumferential direction between adjacent annular bodies.

[0050] In the stent 1c of this embodiment, adjacent pairs of annular bodies 2 (2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k) located in the central portion are connected only by first pattern connecting portions 3 (3a, 3b) and fourth pattern connecting portions 7 (7a, 7b). Therefore, the proportions of the first pattern connecting portions 3 (3a, 3b) and the fourth pattern connecting portions 7 (7a, 7b) are each 50%. In the stent 1c of this embodiment, the first pattern connecting portions 3 (3a, 3b) and the fourth pattern connecting portions 7 (7a, 7b) are arranged alternately in the circumferential direction of the stent, and the inclination directions of each are the same.

[0051] Furthermore, the first pattern connection portions 3a and 3b adjacent to each other in the axial direction of the stent 1c have different inclination directions, and similarly, the fourth pattern connection portions 7a and 7b adjacent to each other in the axial direction of the stent 1c also have different inclination directions. Furthermore, in the stent 1c of this embodiment, the first pattern connection portions 3 (3a, 3b) have a longer axial length than the fourth pattern connection portions 7 (7a, 7b).

[0052] Furthermore, in the stent 1c of this embodiment, one end of the first pattern connecting portion 3 (3a, 3b) is connected to the other end bent portion side of the connecting linear portion 23 or 24 (e.g., 23e, 24f). Specifically, it is connected to a position closer to the other end vertex side than the center of the connecting linear portion 23 or 24 (e.g., 23e, 24f).

[0053] In stent 1c of this embodiment, first pattern connecting portions 3a have one-end curved portions 31a that are curved in the direction opposite to the inclination direction of connecting portions 3a (upward in connecting portions that slope downward to the right in FIG. 8). The apex of this curved portion 31a is close to apex 26 on the other end side of the connecting linear portions to which connecting portions 3a are connected. In addition, first pattern connecting portions 3b have one-end curved portions 31b that are curved in the direction opposite to the inclination direction of the connecting portions (downward in connecting portions that slope upward to the right in FIG. 8). The apex of this curved portion 31b is close to apex 26 on the other end side of the connecting linear portions to which connecting portions 3b are connected.

[0054] In the stent 1c of this embodiment, the first pattern connecting portion of the stent 1c has multiple protrusions extending toward the outer surface. Specifically, the first pattern connecting portion 3 (3a, 3b) protrudes outward when the stent is expanded, forming protrusions on the outer surface of the stent whose protrusion amount increases from both ends of the connecting portion toward the center. The height of the protrusions is preferably 50 μm or more. The distance between the protrusions in the axial direction is approximately the same as the distance between the vertices on the other end of adjacent annular bodies.

[0055] In stent 1c of this embodiment, substantially rectangular closed cells inclined in a first circumferential direction (first direction) of the stent are arranged in parallel in the circumferential direction. Furthermore, adjacent to the substantially rectangular closed cells in the axial direction are substantially rectangular closed cells inclined in a second direction, which is the opposite direction to the first circumferential direction of stent 1c, also arranged in parallel in the circumferential direction. Furthermore, in stent 1c of this embodiment, one end of a substantially rectangular closed cell inclined in the second direction is inserted into a recess between the other ends of the substantially rectangular closed cells inclined in the first direction. This provides expansion retention.

[0056] 7, stent 1c of this embodiment further includes a one-end annular-body connecting portion 8 that connects apex 26 of the other end of annular body 2a located at one end to apex 25 of one end of annular body 2b adjacent to annular body 2a located at one end, and an other-end annular-body connecting portion 8 that connects apex 25 of one end of annular body 2m located at the other end to apex 26 of the other end of annular body 2k adjacent to annular body 2m located at the other end. The axial length of connecting portion 8 is shorter than that of connecting portions 3 and 7. Therefore, stent 1c of this embodiment has so-called closed cells that are approximately diamond-shaped at both ends, and has high axial rigidity.

[0057] As described above, the stent 1c of this embodiment does not have a bent portion on the other end that is a free end, except for the annular body 2m located at the other end of the stent 1c, and even if the stent is exposed to some extent, it can be re-stored within the sheath 12.

[0058] Next, a stent 1d according to an embodiment shown in FIGS. 9 and 10 will be described. In the stent 1d of this embodiment, adjacent sets (first sets) of annular bodies 2 located in the central portion (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, between 2m and 2n) are connected by second pattern connecting portions 4 (4a, 4b) that connect connecting linear portions 23, 24 (e.g., 23e, 24g) to connecting linear portions 23, 24 (e.g., 23f, 24h) located on the other end side of the connecting linear portions 23, 24 (e.g., 23e, 24g), as shown in Figures 9 and 10.

[0059] In stent 1d of this embodiment, adjacent pairs of annular bodies located in the central portion (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, and between 2m and 2n) are connected only by second pattern connecting portions 4 (4a, 4b). In addition, second pattern connecting portions 4a and 4b adjacent to each other in the axial direction of stent 1d have different inclination directions. Furthermore, in the stent 1d of this embodiment, as shown in Figures 9 and 10, the adjacent sets (first sets) of annular bodies 2 located in the central portion (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, between 2m and 2n) of the multiple sets (second sets) of annular bodies 2 (between 2a and 2b, between 2c and 2d, between 2e and 2f, between 2g and 2h, between 2i and 2j, between 2k and 2m, between 2n and 2p) are all connected by short fourth pattern connecting portions 6 (6a, 6b) connecting one end side vertex 25 (e.g., 25g, 25i) and the other end side vertex 26 (e.g., 26f, 26h).

[0060] Therefore, when the first and second sets are combined, the number of second pattern connecting portions 4 (4a, 4b) and the number of fourth pattern connecting portions 6 (6a, 6b) are the same, and the proportion of second pattern connecting portions 4 (4a, 4b) located in the central portion is 50% of the total number of connecting portions in that portion.

[0061] In the stent 1d of this embodiment, the fourth pattern connecting portions 6 (6a, 6b) adjacent to each other in the circumferential direction of the stent are inclined in the same direction, while the fourth pattern connecting portions 6a and 6b adjacent to each other in the axial direction of the stent 1d are inclined in different directions. Furthermore, the fourth pattern connecting portions 6a and 6b have approximately the same axial length.

[0062] In the stent 1d of this embodiment, the fourth pattern connecting portions 6 (6a, 6b) have a shorter axial length than the second pattern connecting portions 4 (4a, 4b). Therefore, the distances between the second set of annular bodies 2 (between 2a and 2b, between 2c and 2d, between 2e and 2f, between 2g and 2h, between 2i and 2j, between 2k and 2m, and between 2n and 2p) are shorter than the distances between the first set of annular bodies 2 (between 2b and 2c, between 2d and 2e, between 2f and 2g, between 2h and 2i, between 2j and 2k, and between 2m and 2n).

[0063] In the stent 1d of this embodiment, the second pattern connecting portion of the stent 1d has multiple protrusions extending toward the outer surface. Specifically, the second pattern connecting portion 4 (4a, 4b) protrudes outward when the stent is expanded, forming protrusions on the outer surface of the stent whose protrusion amount increases from both ends of the connecting portion toward the center. The height of the protrusions is preferably 50 μm or more. The distance between the protrusions in the axial direction is approximately the same as the distance between the vertices on the other end of adjacent annular bodies.

[0064] In stent 1d of this embodiment, generally rectangular closed cells inclined in a first circumferential direction (first direction) of the stent are also arranged in parallel in the circumferential direction. Furthermore, adjacent to the generally rectangular closed cells in the axial direction are generally rectangular closed cells inclined in a second direction, which is the opposite direction to the first circumferential direction of stent 1d, also arranged in parallel in the circumferential direction. Furthermore, in stent 1d of this embodiment, one end of a generally rectangular closed cell inclined in the second direction is inserted into a recess between the other ends of the generally rectangular closed cells inclined in the first direction. This provides expansion retention.

[0065] 9, in the stent 1d of this embodiment, the vertex 26 on the other end side of the annular body 2a located at one end is connected to the vertex 25 on one end side of the annular body 2b adjacent to the annular body 2a located at one end by a connecting portion 6a, and the vertex 25 on one end side of the annular body 2p located at the other end is connected to the vertex 26 on the other end side of the annular body 2n adjacent to the annular body 2p located at the other end by a connecting portion 6a. The connecting portion 6a has a shorter axial length of the stent than the connecting portion 4. Therefore, the stent 1d of this embodiment has so-called closed cells that are approximately diamond-shaped at both ends, and has high axial rigidity.

[0066] When the conformability of the examples of the present invention at bent sections was compared and evaluated, it was found that the stent shown in Figures 1 and 2 had the best conformability, followed by the stent shown in Figures 5 and 6, the stent shown in Figures 7 and 8, and the stent shown in Figures 9 and 10, and then the stent shown in Figures 3 and 4.

[0067] In all the above-mentioned examples, the axial length of the first pattern connecting portions 3 (3a, 3b) is preferably 0.2 mm to 3.0 mm, and more preferably 0.5 mm to 2.0 mm. The inclination angle of the first pattern connecting portions 3 (3a, 3b) with respect to the central axis of the stent is preferably 40 to 70 degrees, and more preferably 45 to 65 degrees.

[0068] The axial length of the second pattern connecting portions 4 (4a, 4b) is preferably 0.2 mm to 3.0 mm, and particularly preferably 0.5 mm to 2.0 mm. The inclination angle of the second pattern connecting portions 4 (4a, 4b) relative to the central axis of the stent is preferably 40 to 70 degrees, and particularly preferably 45 to 65 degrees.

[0069] The axial length of the third pattern connecting portions 5 (5a, 5b) is preferably 0.2 mm to 3.0 mm, and particularly preferably 0.5 mm to 2.0 mm. The inclination angle of the third pattern connecting portions 5 (5a, 5b) relative to the central axis of the stent is preferably 40 to 70 degrees, and particularly preferably 45 to 65 degrees.

[0070] The axial length of the fourth pattern connecting portions 6 (6a, 6b) is preferably 0.1 mm to 1.5 mm, and more preferably 0.15 mm to 1.0 mm. The inclination angle of the fourth pattern connecting portions 6 (6a, 6b) relative to the central axis of the stent is preferably 40 to 70 degrees, and more preferably 45 to 65 degrees.

[0071] The axial length of the fourth pattern connecting portions 7 (7a, 7b) is preferably 0.2 mm to 3.0 mm, and particularly preferably 0.5 mm to 2.0 mm. The inclination angle of the fourth pattern connecting portions 7 (7a, 7b) relative to the central axis of the stent is preferably 40 to 70 degrees, and particularly preferably 45 to 65 degrees.

[0072] A superelastic metal is suitable as a constituent material of the stent. A superelastic alloy is preferably used as the superelastic metal. The superelastic alloy referred to here is generally called a shape memory alloy, and exhibits superelasticity at least at body temperature (around 37°C). Particularly preferred are superelastic alloys such as a Ti-Ni alloy containing 49 to 53 atomic % Ni, a Cu-Zn alloy containing 38.5 to 41.5 weight % Zn, a Cu-Zn-X alloy containing 1 to 10 weight % X (X = Be, Si, Sn, Al, Ga), a Ni-Al alloy containing 36 to 38 atomic % Al, and a Mg-Sc alloy containing 15 to 25 atomic % Sc. The Ti-Ni alloy is particularly preferred. Furthermore, the mechanical properties can be appropriately changed by substituting 0.01 to 10.0% of X to form a Ti-Ni-X alloy (X = Co, Fe, Mn, Cr, V, Al, Nb, W, B, etc.) or 0.01 to 30.0% of Y to form a Ti-Ni-Y alloy (Y = Cu, Pb, Zr), and by selecting the cold working rate and / or the final heat treatment conditions.

[0073] Furthermore, by using the above Ti-Ni alloy, Ti-Ni-X alloy, or Ti-Ni-Y alloy and selecting the cold working rate and / or the final heat treatment conditions, the mechanical properties can be appropriately changed. The buckling strength (yield stress under load when superelastic properties are expressed) of the superelastic alloy used is 5 to 200 kgf / mm 2 (22°C), more preferably 8 to 150 kgf / mm 2 , the recovery stress (yield stress when unloaded) is 3 to 180 kgf / mm 2 (22°C), more preferably 5 to 130 kgf / mm 2The term "superelasticity" used here means that even if the material is deformed (bent, stretched, compressed) to the extent that normal metals would undergo plastic deformation at the operating temperature, it will recover to almost its original shape after the deformation is released without the need for heating.

[0074] When the stent 1 is used for dilating cerebral blood vessels, for example, the diameter of the stent 1 when expanded (uncompressed) is preferably about 0.5 to 6.0 mm, and more preferably 0.9 to 5.0 mm, and the length of the stent when expanded (uncompressed) is preferably about 5 to 50 mm.

[0075] The wall thickness of the stent is preferably about 0.05 to 0.15 mm, and more preferably 0.06 to 0.13 mm. The width of the linear elements constituting the stent is preferably about 0.04 to 0.15 mm, and more preferably 0.05 to 0.13 mm.

[0076] The stent of the present invention may also contain a physiologically active substance in a releasable manner. For example, a method for releasably containing a physiologically active substance includes coating the surface of the stent with a polymer (e.g., a biodegradable polymer) containing the physiologically active substance. The biodegradable polymer is not particularly limited as long as it is degraded enzymatically or non-enzymatically in the body and the degradation products are not toxic. For example, polylactic acid, polyglycolic acid, polylactic acid-polyglycolic acid copolymer, polycaprolactone, polylactic acid-polycaprolactone copolymer, polyorthoester, polyphosphazene, polyphosphate ester, polyhydroxybutyric acid, polymalic acid, poly-α-amino acid, collagen, gelatin, laminin, heparan sulfate, fibronectin, vitronectin, chondroitin sulfate, hyaluronic acid, polypeptide, chitin, chitosan, etc. can be used.

[0077] Examples of physiologically active substances that can be used include substances that promote the dissolution or metabolism of thrombi or thrombus complexes, substances that suppress the growth of thrombi or thrombus complexes, substances 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, biomaterials, interferon, and epithelial cells produced by genetic engineering. Mixtures of two or more of the above substances may also be used.

[0078] Substances that promote the dissolution or metabolism of thrombi or thrombus complexes or that inhibit the buildup of thrombi or thrombus complexes include streptokinase, plasminogen activator, urokinase, staphinokinase, lumbrokinase, nattokinase, or analogs thereof. Substances that inhibit the buildup of thrombi or thrombus complexes include antiplatelet drugs such as acetylsalicylic acid, ticlopidine, dipyridamole, cilostazol, beraprost Na, limaprost alfatex, ethyl icosapentoenoate, salvogrelate hydrochloride, trapidil, clopidogrel, prasugrel, and analogs thereof, or anticoagulants such as GP IIb / IIIa antagonists, heparin, and warfarin potassium.

[0079] Next, a stent delivery system according to an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 11 is a partially omitted front view of a stent delivery system according to an embodiment of the present invention, and Fig. 12 is an enlarged longitudinal sectional view of the vicinity of the distal end of the stent delivery system shown in Fig. 11.

[0080] The stent delivery system 10 of this embodiment comprises a sheath 12, a stent 1 housed within the distal end of the sheath 12, and an inner tube 14 that is slidably inserted through the sheath 12 and used to release the stent 1 from the distal end of the sheath 12.

[0081] In the stent delivery system 10 of this embodiment, the stent 1 is the above-mentioned self-expanding stent, which is formed in a cylindrical shape, compressed in the central axis direction when inserted into the body, and expands outward when placed in the body, and can restore to its pre-compression shape.

[0082] As shown in FIG. 11, the stent delivery system 10 of this embodiment comprises a sheath 12, a self-expanding stent 1, and an inner tube 14. As shown in Figures 11 and 12, the sheath 12 is a tubular body with openings at the distal and proximal ends. The distal opening functions as a release port for the stent 1 when the stent 1 is placed in a stricture within a body cavity. The stent 1 is released from this distal opening by sliding the sheath 12 toward the proximal end, where it expands as the stress load is released and it returns to its pre-compression shape. The distal end of the sheath 12 serves as a stent storage region 15 for storing the stent 1 inside. The sheath 12 also has a side hole 41 provided on the proximal side of the storage region 15. The side hole 41 is for leading out a guide wire to the outside.

[0083] The outer diameter of the sheath 12 is preferably about 0.4 to 4.0 mm, and particularly preferably 0.5 to 3.0 mm. The inner diameter of the sheath 12 is preferably about 0.3 to 2.0 mm. The length of the sheath 12 is preferably about 300 to 2500 mm, and particularly preferably about 300 to 2000 mm.

[0084] 11, a sheath hub 16 is fixed to the proximal end of the sheath 12. The sheath hub 16 includes a sheath hub body and a valve body (not shown) that is housed within the sheath hub body and that slidably holds the inner tube 14 in a liquid-tight manner. The sheath hub 16 also includes a side port 18 that branches off obliquely rearward from near the center of the sheath hub body. The sheath hub 16 also preferably includes an inner tube locking mechanism that restricts movement of the inner tube 14.

[0085] As shown in Figures 11 and 12, the inner tube 14 comprises a shaft-shaped inner tube main body portion 40, a tip portion 47 provided at the tip of the inner tube main body portion 40 and protruding from the tip of the sheath 12, and an inner tube hub 17 fixed to the base end of the inner tube main body portion 40.

[0086] The distal end portion 47 preferably projects beyond the distal end of the sheath 12 and is formed in a tapered shape that gradually reduces in diameter toward the distal end, as shown in Figure 12. Forming it in this manner facilitates insertion into a stricture. The inner tube 14 is also preferably provided with a stopper that is located distal to the stent 1 and prevents the sheath from moving toward the distal end. The base end of the distal end portion 47 is capable of abutting against the distal end of the sheath 12, functioning as the stopper.

[0087] As shown in Fig. 12, the inner tube 14 is also provided with two protrusions 43, 45 for holding the self-expanding stent 1. The protrusions 43, 45 are preferably annular protrusions. A stent-holding protrusion 43 is provided on the proximal end side of the distal end 47 of the inner tube 14. A stent-pushing protrusion 45 is provided a predetermined distance proximal to the stent-holding protrusion 43. The stent 1 is positioned between these two protrusions 43, 45. The outer diameters of these protrusions 43, 45 are large enough to abut against the compressed stent 1, which will be described later.

[0088] Therefore, the movement of the stent 1 toward the distal end is restricted by the protrusion 43, and the movement toward the proximal end is restricted by the protrusion 45. Furthermore, when the inner tube 14 moves toward the distal end, the protrusion 45 pushes the stent 1 toward the distal end, and the stent 1 is ejected from the sheath 12. Furthermore, the proximal end side of the stent-pushing protrusion 45 preferably has a tapered portion 46 that gradually reduces in diameter toward the proximal end, as shown in Fig. 12. Similarly, the proximal end side of the stent-retaining protrusion 43 preferably has a tapered portion 44 that gradually reduces in diameter toward the proximal end, as shown in Fig. 12.

[0089] This allows the inner tube 14 to protrude from the distal end of the sheath 12, and after the stent 1 is released from the sheath, the protruding portion is prevented from getting caught on the distal end of the sheath when the inner tube 14 is retracted into the sheath 12. The protruding portions 43 and 45 may also be formed as separate members made of an X-ray contrast material. This allows the position of the stent to be accurately determined under X-ray contrast, making the procedure easier.

[0090] As shown in Figure 12, the inner tube 14 has a lumen 48 that extends from its distal end to at least the proximal side of the stent-storing site 15 of the sheath 12, and an inner tube side hole 42 that communicates with the lumen 48 proximal to the stent-storing site. In the stent delivery system 10 of this embodiment, the lumen 48 terminates at the site where the side hole 42 is formed. The lumen 48 is used to insert one end of a guidewire from the distal end of the stent delivery system 10, partially pass through the inner tube, and then lead it to the outside from the side surface of the inner tube. The inner tube side hole 42 is located slightly distal to the sheath side hole 41 of the stent delivery system 10. The center of the inner tube side hole 42 is preferably 0.5 to 10 mm distal from the center of the sheath side hole 41.

[0091] The stent delivery system is not limited to the above-mentioned type, and the lumen 48 may extend to the proximal end of the inner tube. In this case, the side hole 41 of the sheath is not necessary. The inner tube 14 passes through the sheath 12 and protrudes from the proximal end opening of the sheath 12. An inner tube hub 17 is fixed to the proximal end of the inner tube 14, as shown in FIG.

[0092] In addition, in all of the stents of the above-described embodiments, the stent may be provided with a contrast marker at one end and the other end. The contrast marker may be any type, such as for X-ray imaging or ultrasound imaging. The marker is formed from a contrast material, such as an X-ray contrast material or an ultrasound contrast material. Suitable materials for forming the marker include, for example, gold, platinum, tungsten, iridium, palladium, or alloys thereof, or gold-palladium alloys, platinum-iridium, NiTiPd, NiTiAu, etc.

[0093] The stent for placement in vivo of the present invention is a stent for placement in vivo in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by a connecting portion. The annular body is formed by a single endless linear element having a plurality of one-end vertices located on one axial end side of the stent, a plurality of other-end vertices located on the other axial end side of the stent, and a plurality of connecting linear portions connecting the one-end vertices to the other-end vertices. A plurality of pairs of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and further, 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions connecting one-end vertices to connecting linear portions located on the one end side of the one-end vertices or second pattern connecting portions connecting connecting linear portions to connecting linear portions located on the other end side of the connecting linear portions, and the remaining connecting portions located in the central portion are first pattern connecting portions not selected in the basic pattern connecting portions. The pattern connecting portion is at least one type selected from a connecting portion or a second pattern connecting portion, a third pattern connecting portion connecting an other end vertex and a connecting linear portion located on the other end side of the other end vertex, and a fourth pattern connecting portion connecting an one end vertex and an other end vertex located on the one end side of the one end vertex, and further, the number of connecting portions connecting adjacent annular bodies located in the central portion is the same as the number of one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less. Therefore, it has good storability and followability due to good radial compression, and sufficient expansion force. [Industrial Applicability]

[0094] The stent for placement in a living body of the present invention is as follows. (1) A stent for placement in vivo, in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by a connecting portion, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of the connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end side vertex and the connecting linear portion located on the one end side of the one end side vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are basic pattern connecting portions that are not selected in the basic pattern connecting portions. a third pattern connecting portion connecting the one end vertex to the connecting linear portion located on the other end side of the one end vertex; and a fourth pattern connecting portion connecting the one end vertex to the other end vertex located on the one end side of the one end vertex, and further, the number of connecting portions connecting adjacent annular bodies located in the central portion is the same as the number of the one end vertices or the other end vertices of the annular bodies connected by the connecting portions, or is one more or one less.

[0095] This stent for placement in vivo is a stent for placement in vivo in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by a connecting portion. The annular body is formed by a single endless linear element having a plurality of one-end vertices located on one axial end side of the stent, a plurality of other-end vertices located on the other axial end side of the stent, and a plurality of connecting linear portions connecting the one-end vertices to the other-end vertices. A plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and further, 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions connecting one-end vertices to connecting linear portions located on the one end side of the one-end vertices or second pattern connecting portions connecting connecting linear portions to connecting linear portions located on the other end side of the connecting linear portions, and the remaining connecting portions located in the central portion are first pattern connecting portions not selected in the basic pattern connecting portions. The pattern connecting portion is at least one type selected from a connecting portion or a second pattern connecting portion, a third pattern connecting portion connecting an other end vertex and a connecting linear portion located on the other end side of the other end vertex, and a fourth pattern connecting portion connecting an one end vertex and an other end vertex located on the one end side of the one end vertex, and further, the number of connecting portions connecting adjacent annular bodies located in the central portion is the same as the number of one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less. Therefore, it has good storability and followability due to good radial compression, and sufficient expansion force.

[0096] The above embodiment may also be as follows. (2) A stent for placement in vivo as described in (1) above, wherein the adjacent sets of annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end vertex and the connecting linear portion located on the one end side of the one end vertex, and a third pattern connecting portion that connects the other end vertex and the connecting linear portion located on the other end side of the other end vertex, and the first pattern connecting portion and the third pattern connecting portion are alternately arranged in the circumferential direction between the adjacent annular bodies. (3) A stent for placement in vivo as described in (1) above, in which all adjacent annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end vertex to the connecting linear portion located on the one end side of the one end vertex, and a third pattern connecting portion that connects the other end vertex to the connecting linear portion located on the other end side of the other end vertex, and the first pattern connecting portions and the third pattern connecting portions are arranged alternately in the circumferential direction between adjacent annular bodies. (4) A stent for placement in vivo as described in (1) above, wherein the adjacent first set of annular bodies located in the central portion are all connected by a second pattern connecting portion that connects the connecting linear portion to the connecting linear portion located on the other end side of the connecting linear portion, and the stent has a plurality of the first set of annular bodies, and the adjacent first sets are all connected by a fourth pattern connecting portion that connects the vertex on one end side to the vertex on the other end side. (5) A stent for placement in vivo as described in (1) above, wherein the adjacent annular bodies located in the central portion have second pattern connecting portions that connect the connecting linear portion with the connecting linear portion located on the other end side of the connecting linear portion, and fourth pattern connecting portions that connect the vertex on one end side with the vertex on the other end side, arranged alternately in the circumferential direction, and the second pattern connecting portions that are adjacent in the axial direction have different circumferential extension directions, and the fourth pattern connecting portions that are adjacent in the axial direction have different circumferential extension directions. (6) The first set of adjacent annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end vertex to the connecting linear portion located on the one end side of the one end vertex, and a third pattern connecting portion that connects the other end vertex to the connecting linear portion located on the other end side of the other end vertex, and the first pattern connecting portions and the third pattern connecting portions are arranged alternately in the circumferential direction of the first set of annular bodies, a stent for placement in vivo as described in (1) above. (7) The adjacent annular bodies of the first set located in the central portion are connected by a first pattern connecting portion that connects the one end vertex and the connecting linear portion located on the one end side of the one end vertex, and a third pattern connecting portion that connects the other end vertex and the connecting linear portion located on the other end side of the other end vertex, and the first pattern connecting portions and the third pattern connecting portions are alternately arranged in the circumferential direction of the annular bodies of the first set, The stent is a stent for placement in vivo as described in (1) above, which comprises a plurality of the first set of annular bodies, and adjacent first sets are all connected by a fourth pattern connecting portion that connects the apex on one end side to the apex on the other end side. (8) A stent for placement in vivo as described in (1) above, wherein the adjacent sets of annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end side vertex and the connecting linear portion located on the one end side of the one end side vertex, and a fourth pattern connecting portion that connects the one end side vertex and the other end side vertex, and the first pattern connecting portion and the fourth pattern connecting portion are arranged alternately in the circumferential direction. (9) A stent for placement in vivo as described in (1) above, wherein all adjacent annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end vertex to the connecting linear portion located on the one end side of the one end vertex, and a fourth pattern connecting portion that connects the one end vertex to the other end vertex that is located on the one end side of the one end vertex, and the first pattern connecting portions and the fourth pattern connecting portions are arranged alternately in the circumferential direction. (10) A stent for placement in vivo described in any of (1) to (9) above, wherein the connecting portions adjacent to each other in the axial direction of the stent in all adjacent annular bodies located in the central portion have different circumferential directions in which the connecting portions extend. (11) A stent for placement in vivo described in any one of (1) to (9) above, wherein adjacent connecting portions of the same pattern located in the central portion of the stent in the axial direction extend in different circumferential directions. (12) A stent for placement in vivo according to any one of (4), (5), (7) to (11) above, wherein the stent comprises: an other-end bent portion having the vertex on the other end side of the annular body located at one end; a one-end annular body connecting portion connecting the one-end bent portion having the vertex on the one end side of the annular body located at one end to the one-end bent portion having the vertex on the one end side of the annular body adjacent to the annular body located at the one end; and an other-end annular body connecting portion connecting the one-end bent portion having the vertex on the one end side of the annular body located at the other end to the one-end bent portion having the vertex on the other end side of the annular body adjacent to the annular body located at the other end, wherein the one-end annular body connecting portion includes the fourth pattern connecting portion, and the other-end annular body connecting portion includes the fourth pattern connecting portion. (13) A stent for placement in vivo described in any one of (1) to (12) above, wherein the connecting portions are inclined in the axial direction of the stent, and the connecting portions connecting adjacent annular bodies are all inclined in the same direction. (14) The stent for placement in a living body according to any one of (1) to (13) above, which has a plurality of protrusions on the outer surface of the stent. (15) The stent for placement in vivo according to (14) above, wherein the height of the convex portions is 50 μm or more. (16) A stent for placement in vivo described in any one of (1) to (15) above, which is formed in an approximately cylindrical shape, is compressed in the central axis direction when inserted into the body, and expands outward and restores to its original shape before compression when placed in the body.

[0097] The stent delivery system of the present invention is as follows. (17) A stent delivery system comprising a sheath, the stent of (16) housed in the distal end of the sheath, and a shaft for passing through the sheath and releasing the stent from the distal end of the sheath.

Claims

1. A stent for placement in vivo, in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in an axial direction, and adjacent annular bodies are connected by a connecting portion, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, the plurality of adjacent sets of annular bodies located in the central portion are connected by the first pattern connecting portion that connects the one end vertex to the connecting linear portion located on the one end side of the one end vertex, and the third pattern connecting portion that connects the other end vertex to the connecting linear portion located on the other end side of the other end vertex, and the first pattern connecting portion and the third pattern connecting portion are arranged alternately in the circumferential direction between adjacent annular bodies.

2. A stent for placement in a living body, in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, a plurality of sets of adjacent annular bodies located at least in a central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of a first pattern connecting portion connecting the one end vertex to the connecting linear portion located on one end side of the one end vertex, or a second pattern connecting portion connecting the connecting linear portion to the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion not selected in the basic pattern connecting portion, a third pattern connecting portion connecting the other end vertex to the connecting linear portion located on the other end side of the other end vertex, and a fourth pattern connecting portion connecting the one end vertex to the other end vertex located on the one end side of the one end vertex, Furthermore, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as or one more or one less than the number of vertices on the one end side or the number of vertices on the other end side of the annular bodies connected by the connecting portions, Furthermore, all of the adjacent annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end side vertex and the connecting linear portion located on the one end side of the one end side vertex, and a third pattern connecting portion that connects the other end side vertex and the connecting linear portion located on the other end side of the other end side vertex, and the first pattern connecting portion and the third pattern connecting portion are arranged alternately in the circumferential direction between adjacent annular bodies.

3. A stent for placement in a living body, in which a plurality of annular bodies formed into a ring shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, the annular bodies of the first set, which are adjacent and located in the central portion, are all connected by a second pattern connecting portion that connects the connecting linear portion to the connecting linear portion located on the other end side of the connecting linear portion; the stent comprises a plurality of annular bodies of the first set, and adjacent first sets are all connected by a fourth pattern connecting portion that connects the vertex on one end side to the vertex on the other end side.

4. A stent for placement in a living body, in which a plurality of annular bodies formed into a ring shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, in the adjacent annular bodies located in the central portion, second pattern connection portions that connect the connecting linear portion to the connecting linear portion located on the other end side of the connecting linear portion and fourth pattern connection portions that connect the vertex on one end side to the vertex on the other end side are arranged alternately in the circumferential direction, and the second pattern connection portions that are adjacent in the axial direction extend in different directions in the circumferential direction, and the fourth pattern connection portions that are adjacent in the axial direction extend in different directions in the circumferential direction, characterized in that

5. A stent for placement in a living body, in which a plurality of annular bodies formed into a ring shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, the adjacent first set of annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end side vertex to the connecting linear portion located on the one end side of the one end side vertex, and a third pattern connecting portion that connects the other end side vertex to the connecting linear portion located on the other end side of the other end side vertex, and the first pattern connecting portions and the third pattern connecting portions are arranged alternately in the circumferential direction of the first set of annular bodies, characterized in that

6. A stent for placement in a living body, in which a plurality of annular bodies formed into a ring shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, adjacent annular bodies of the first set located in the central portion are connected by a first pattern connecting portion that connects the one end vertex and the connecting linear portion located on the one end side of the one end vertex, and a third pattern connecting portion that connects the other end vertex and the connecting linear portion located on the other end side of the other end vertex, and the first pattern connecting portions and the third pattern connecting portions are arranged alternately in the circumferential direction of the annular bodies of the first set, The stent is characterized in that it comprises a plurality of the first set of annular bodies, and adjacent first sets are all connected by a fourth pattern connecting portion that connects the apex on one end side to the apex on the other end side.

7. A stent for placement in a living body, in which a plurality of annular bodies formed into a ring shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, the plurality of adjacent sets of annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end side vertex and the connecting linear portion located on the one end side of the one end side vertex, and a fourth pattern connecting portion that connects the one end side vertex and the other end side vertex, and the first pattern connecting portion and the fourth pattern connecting portion are arranged alternately in the circumferential direction,

8. A stent for placement in a living body, in which a plurality of annular bodies formed into a ring shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, all of the adjacent annular bodies located in the central portion are connected by a first pattern connecting portion that connects the one end side vertex to the connecting linear portion located on the one end side of the one end side vertex, and a fourth pattern connecting portion that connects the one end side vertex to the other end side vertex located on the one end side of the one end side vertex, and the first pattern connecting portions and the fourth pattern connecting portions are arranged alternately in the circumferential direction.

9. A stent for placement in a living body, in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, the stent for placement in vivo is characterized in that the connecting portions adjacent to each other in the axial direction of the stent in all adjacent annular bodies located in the central portion have different circumferential directions in which the connecting portions extend.

10. A stent for placement in a living body, in which a plurality of annular bodies formed into an annular shape by linear elements are arranged in the axial direction, and adjacent annular bodies are connected by connecting parts, the annular body is formed by a single endless linear element having a plurality of one-end vertices located on one end side in the axial direction of the stent, a plurality of other-end vertices located on the other end side in the axial direction of the stent, and a plurality of connecting linear portions connecting the one-end vertices and the other-end vertices, The plurality of sets of adjacent annular bodies located at least in the central portion of the stent are connected by a plurality of connecting portions, and 25% to 75% of the total number of connecting portions located in the central portion are basic pattern connecting portions consisting of first pattern connecting portions that connect the one end vertex and the connecting linear portion located on the one end side of the one end vertex, or second pattern connecting portions that connect the connecting linear portion and the connecting linear portion located on the other end side of the connecting linear portion, and the remaining connecting portions located in the central portion are not selected from the basic pattern connecting portions. the annular bodies are at least one type of pattern connecting portion selected from the first pattern connecting portion or the second pattern connecting portion, a third pattern connecting portion connecting the one end side vertex and the connecting linear portion located on the other end side of the one end side vertex, and a fourth pattern connecting portion connecting the one end side vertex and the other end side vertex located on the one end side of the one end side vertex, and further, the number of connecting portions connecting the adjacent annular bodies located in the central portion is the same as the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, or is one more or one less than the number of the one end side vertices or the other end side vertices of the annular bodies connected by the connecting portion, Furthermore, a stent for placement in vivo is characterized in that adjacent connecting portions of the same pattern located in the central portion of the stent in the axial direction have different circumferential directions in which the connecting portions extend.

11. 11. The stent for placement in vivo according to claim 3, 4, 6 to 10, wherein the stent comprises: an other-end bent portion having the vertex on the other end side of the annular body located at one end; a one-end bent portion having the vertex on the one end side of the annular body located at one end; a one-end annular body connecting portion connecting the one-end bent portion having the vertex on the one end side of the annular body located at the one end and an adjacent annular body; and an other-end annular body connecting portion connecting the one-end bent portion having the vertex on the one end side of the annular body located at the other end and an other-end bent portion having the vertex on the other end side of the annular body located at the other end; wherein the one-end annular body connecting portion includes the fourth pattern connecting portion, and the other-end annular body connecting portion includes the fourth pattern connecting portion.

12. 12. The stent for placement in vivo according to claim 1, wherein the connecting portions are inclined in the axial direction of the stent, and the connecting portions connecting adjacent annular bodies are all inclined in the same direction.

13. 13. The stent for placement in a living body according to claim 1, wherein the stent has a plurality of protrusions on its outer surface.

14. 14. The stent for placement in vivo according to claim 13, wherein the height of the convex portions is 50 μm or more.

15. 15. A stent for placement in vivo according to any one of claims 1 to 14, which is formed in a substantially cylindrical shape, is compressed in the direction of its central axis when inserted into a living body, and expands outward and restores to its pre-compression shape when placed in the living body.

16. A stent delivery system comprising a sheath, the stent of claim 15 housed in the distal end of the sheath, and a shaft for passing through the sheath and releasing the stent from the distal end of the sheath.

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