JP3475039B2 - Indwelling stent - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stent for in-vivo use, which is used for ameliorating a stenosis portion that occurs in a living body such as a blood vessel, a bile duct, a trachea, an esophagus, a urethra, and other organs.

[0002]

2. Description of the Related Art A stent is a generally tubular device having a function of keeping a blood vessel or other empty portion of an incised tube open, and is effective in improving a narrowed portion such as a blood vessel. Stents are classified into self-expandable stents and balloon expandable stents according to their functions and placement methods. The balloon expandable stent does not have an expansion function in the stent itself. After inserting the stent at the target site, the balloon is positioned inside the stent to expand the balloon, and the expansion force of the balloon expands (plastically deforms) the stent. Fix it by making close contact with the inner surface of the target area. This type of stent requires the expansion work of the stent as described above. Examples of balloon expandable stents include those disclosed in Japanese Patent Publication No. 4-6377 and Japanese Patent Application Laid-Open No. 2-174859. Japanese Examined Patent Publication No. 4-6377 and Japanese Patent Laid-Open No. Hei 2
The stent disclosed in Japanese Patent No. 174859 has a groove formed in the axial direction of the pipe, and by combining the grooves, a continuous rhombus is formed when expanded.

[0003]

[Patent Document 1] Japanese Patent Publication No. 4-6377 discloses a diamond shape which is continuous after being expanded, and therefore has excellent shape retention after expansion, and for example, resistance to the force of blood vessel contraction. Is strong. Further, when it is desired to partially increase the diameter at the time of expansion, there is an advantage that a balloon having that diameter can be added and inserted into the stent for expansion. However, the non-expanded side shape is a state in which a groove is dug in the pipe in the axial direction, so there is no flexibility in the axial direction and it is possible to pass a bent blood vessel when inserting this stent to the lesion site. It can be difficult. Further, when expanded, the entire length is considerably shortened, so that the entire stenosis of the target blood vessel cannot be expanded, and the expected placement site under the X-ray contrast and the actual placement state of the stent. There may be a gap between them, and it may not be possible to effectively improve the narrowed portion.

Therefore, an object of the present invention is to have an excellent shape-retaining property after dilation, to easily pass through a bent blood vessel, and even when dilated, the entire length of the blood vessel hardly changes, so that the desired blood vessel can be obtained. The present invention provides a stent in which the entire stenosis can be expanded, and a stent can be placed without being displaced from an arrangement site that was supposed under X-ray imaging, and the stenosis can be effectively improved.

[0005]

[Means for Solving the Problems] What achieves the above-mentioned object is that it is formed in a substantially tubular body, has a diameter for insertion into a living body, and has a force that spreads radially outward from the inside of the tubular body. A stent that is expandable when loaded (loaded),
The stent has a plurality of substantially elliptical or polygonal constituent elements that are long in the axial direction of the stent and open at the center, and are arranged so as to surround the central axis of the stent, and adjacent portions of the constituent elements are connected. And a plurality of the annular units are arranged in the axial direction of the stent, and the connecting portion of one annular unit and the connecting portion of an adjacent annular unit are connected by a connecting portion. The stent has at least one connection.

It is preferable that the stent has at least three annular units in the axial direction, and that the annular units at both ends are thinner than the other annular units. Furthermore, it is preferable that the substantially elliptical or polygonal component has a width at both ends in the axial direction narrower than that of the other portions. Further, the stent has at least three annular units in the axial direction,
Moreover, it is preferable that the annular units at both ends have a smaller cross-sectional area of the unit forming material than the other annular units. Further, it is preferable that the axially opposite end portions of the substantially elliptical or polygonal component have a smaller cross-sectional area than other portions.

Further, it is preferable that only one connecting portion is formed between the adjacent annular units. Further, it is preferable that the connecting portions are arranged so as not to be continuous with the adjacent connecting portions. In particular, the connection is
It is preferable that the arrangement position is spiral when viewed from the entire stent. The constituent elements are preferably arranged at substantially equal angular intervals with respect to the central axis of the stent. Furthermore, the substantially oval or polygonal components are arranged substantially linearly with respect to the axial direction of the stent, and the connecting portion is also substantially parallel to the axial direction of the stent. preferable. Further, an end portion of the constituent element of the adjacent annular unit may enter a space formed between the connecting portion of the annular unit and two constituent elements connected by the connecting portion. preferable. Further, in a state in which the stent was parallel to the long central axis of the stent is cut in a direction expansion, the connection portion, to the length and direction of the stent, may be inclined at a predetermined angle degrees.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The stent of the present invention will be described with reference to the embodiments shown in the drawings. FIG. 1 is a perspective view of an embodiment of the stent of the present invention. FIG. 2 is a front view of the stent shown in FIG. FIG. 3 is a partially omitted cross-sectional view of the stent shown in FIG. FIG. 4 is a side view of the stent shown in FIG. FIG. 5 is a development view of the stent shown in FIG. 1 before expansion. FIG. 6 is a front view of the stent shown in FIG. 1 after expansion. FIG. 7 is a developed view of the stent after expansion. FIG. 8 is an explanatory diagram for explaining a state in which the stent is inserted.

The stent 1 of the present invention is formed in a substantially tubular body, has a diameter for insertion into a living body, and is expandable when a force spreading radially outward from the inside of the tubular body is applied. It is a so-called balloon balloon expandable stent. As shown in FIGS. 1 to 3, the stent 1 has a substantially elliptical or polygonal component 2 which is long in the axial direction of the stent 1 and has an opening in the center, and is substantially equiangularly spaced from the central axis of the stent. Are arranged on a circle around
Moreover, the annular unit 4 (4a, 4b, 4c, 4d, 4e, 4f) in which the circumferentially adjacent portions (side portions) of the constituent elements are connected by the connection portion 3 (3a, 3b, 3c, 3d). And a plurality of annular units 4a, 4b, 4c, 4
d, 4e, and 4f are arranged in the axial direction of the stent 1. Further, the connecting portion 3 of one annular unit 4 and the connecting portion 3 of the adjacent annular unit 4 are connected to each other by the connecting portions 5 (5a, 5b, 5).
c, 5d, 5e) are connected at least at one place. From a different point of view, the stent 1 is a tubular body formed by connecting a large number of annular units 4 with connecting portions 5.

The annular unit 4 comprises, in this embodiment, four components 2a, 2b, 2 arranged at substantially equal angular intervals.
c, 2d. One component is formed in a substantially elliptical shape that is long in the axial direction of the stent 1, and the center is opened in a substantially elliptical shape corresponding to the shape of the component. In this way, each constituent element has a shape that forms an independent closed system, in other words, the constituent element is a ring-shaped element that opens on the side surface of the stent 1. Since the component has such a shape, it exerts a strong expansion holding force. In addition, as shown in FIG. 4 which is a side view, each of the constituent elements 2a, 2b, 2c and 2d is circumferentially arranged so that the whole is substantially equidistant from the central axis of the stent 1 (annular unit 4). It is curved.

The constituent element is a connecting portion 3a, 3b, 3c, 3d in which the center of the axial side portion of the stent 1 and the center of the axial side portion of another constituent element adjacent in the radial direction are short.
Connected by. That is, the connecting portions 3a, 3b, 3c,
3d connects each component 2a, 2b, 2c, 2d in the circumferential direction. Since the connecting portion 3 does not substantially change even when the stent 1 is expanded, the force at the time of expansion is easily applied to the center of each constituent element, and each constituent element can be uniformly expanded (deformed). The number of constituent elements is not limited to four, but 3 to 8 is preferable. Further, the shape of the constituent element is preferably a substantially elliptical shape, but may be a polygonal shape, for example, a rhombus, a rectangle long in the axial direction, a hexagon, an octagon, or the like. The ellipse shape is preferable because of the stability of deformation when the stent is expanded.

The connecting portion 3 of the annular unit 4 and the connecting portion 3 of the adjacent annular unit 4 are relatively long (longer than the connecting portion) and are formed by the connecting portion 5 formed parallel to the axial direction of the stent 1. It is connected. Specifically, the annular unit 4a and the adjacent annular unit 4b are connected to each other by the connecting portions 3a, 3
They are connected by a connecting portion 5a connecting between a. The annular unit 4b and the adjacent annular unit 4c are connected by a connecting portion 5b that connects the connecting portions 3b and 3b. The annular unit 4c and the adjacent annular unit 4d are connected by a connecting portion 5c that connects the connecting portions 3c, 3c. The ring-shaped unit 4d and the ring-shaped unit 4e adjacent to the ring-shaped unit 4d connect the connection portions 3d and 3d to each other.
Are connected by. The annular unit 4e and the adjacent annular unit 4f are connected by a connecting portion 5e that connects the connecting portions 3a, 3a.

These connecting portions 5a, 5b, 5c, 5d, 5
e does not substantially change when the stent 1 is expanded.
Since the connecting portion 5 and the connecting portion 3 do not substantially change due to the expansion of the stent 1, the entire length of the entire stent 1 hardly changes before and after expansion, and the stent may become extremely short after expansion. Absent. In other words, the connecting portion 3 for connecting the expansion element does not move in the axial direction even when the stent is expanded, and since the connecting portions are connected by the connecting portion 5 parallel to the axis, the total length of the stent is almost the same. It does not shorten.

The connecting portion 5 is provided so as to connect the adjacent annular units 4 at only one place. Although two or more places may be connected, it is preferable to connect only one place as in the embodiment in order to improve followability to the deformation of blood vessels. Further, in this embodiment, the connecting portions 5 are arranged so as not to be continuous with the adjacent connecting portions. For this reason, it is possible to prevent the load when one annular unit 4 is changed so as to follow the deformation of the blood vessel from being directly (or linearly) transmitted to the annular units 4 which are not adjacent to each other, and the annular units are Demonstrate individual independent extensions. Further, as in the embodiment, the connecting portions 5a, 5b, 5
If the arrangement of c, 5d, and 5e is spiral when viewed from the entire stent 1, it is favorable because it is less likely to be affected by annular units that are not adjacent to each other.

Further, the respective constituent elements are aligned substantially linearly with respect to the axial direction of the stent 1, so that all the connecting portions 5 are also parallel with the axial direction of the stent 1.
Therefore, the connecting portion 5 is unlikely to be twisted. Furthermore, all the connecting portions 3 are orthogonal to the axial direction of the stent 1. Therefore, the connecting portion 5 is also unlikely to be twisted. Further, the components 2a, 2b, 2c, 2d are
When the stent 1 is expanded, both ends 21 in the axial direction
The a and 21b are deformed so as to be spread. In order to ensure this deformation and to surely manifest this deformation at both ends, it is assumed that the axial ends of the constituent elements 2a, 2b, 2c, 2d have a smaller cross-sectional area than other portions. Has become. Specifically, in the stent 1 of this example, the widths of both axial end portions 21a and 21b are narrower than those of the other portions. Further, the thickness of the both end portions 21a and 21b in the axial direction is not limited to this, and may be thinner than other portions.

Further, as shown in FIG. 3, the annular units 4a and 4f located at both ends of the stent 1 have a smaller cross-sectional area of the unit forming material than the other annular units 4b, 4c, 4d and 4e. There is. Therefore, the expansion force of the both end portions exerted when the stent 1 is expanded is lower than that of the other portions, but conversely, the followability to the bending of the blood vessel is improved, and both ends of the stent are Has a good affinity. Specifically, the annular unit 4a
As a method of reducing the wall thickness of the portions 4f and 4f, after forming the stent into the final shape, the annular units 4a and 4
It can be performed by chemically or mechanically polishing the f portion. The chemical polishing is preferably performed by immersing it in a stainless chemical polishing liquid. As the stainless chemical polishing liquid, any liquid capable of dissolving stainless steel may be used. For example, a mixed liquid of hydrochloric acid and nitric acid is used as a basic component, and an organic sulfur compound for adjusting the dissolution rate, smoothing and imparting gloss And those to which a surfactant is added are preferable. However, the width of the forming material of the annular units 4a and 4f is not limited to this, and the width of the other annular units
It may be narrower than the width of the forming material of b, 4c, 4d and 4e.

Further, the material for forming the annular unit in the central portion of the stent 1 may have the largest cross-sectional area, and the material for forming the annular unit 4 may have a smaller cross-sectional area toward the end. Specifically, the thickness of the annular unit 4 in the central portion of the stent 1 is thickest and becomes thinner toward the ends. More specifically, the annular units 4c and 4d located in the center of the stent 1 are made thickest to have the largest thickness.
The annular units 4b and 4e adjacent to c and 4d are made thinner than the annular units 4c and 4d, and the annular units 4a and 4f located at both ends are made thinner.
It is thinner than b and 4e. By doing this,
A sufficient expansion force is exerted in the central portion, the followability to the bending of the blood vessel is improved, and both ends of the stent 1 have a better affinity with the blood vessel. In addition, the width of the forming material of the annular unit in the central portion of the stent 1 is the widest,
The width of the forming material of the annular unit may become narrower toward the end.

The material for forming the stent 1 is preferably one having a certain degree of biocompatibility, and examples thereof include stainless steel, tantalum or a tantalum alloy, platinum or a platinum alloy, gold or a gold alloy, and a cobalt base alloy. Alternatively, precious metal plating (gold, platinum) may be applied after the stent shape is produced. As stainless steel, SUS316L, which has the most corrosion resistance, is suitable. Further, it is preferable to anneal after forming the final shape of the stent 1. By performing the annealing, the flexibility and plasticity of the entire stent are improved, and the indwelling property in a bent blood vessel is improved. Compared to the case without annealing, the force to restore the pre-expansion shape after expanding the stent, in particular, the force to return to the linear shape developed when expanded at the bent blood vessel site is reduced, The physical irritation applied to the curved inner wall of the blood vessel is reduced, and the factor of restenosis can be reduced. Annealing is preferably performed by heating to 900 to 1200 ° C. in an inert gas atmosphere (for example, argon gas) and then slowly cooling so that an oxide film is not formed on the surface of the stent.

The non-expanded diameter of the stent 1 is 1.2 to
1.8 mm is suitable, especially 1.3 to 1.6 m
m is more preferred. Also, the length of one annular unit,
In other words, the axial length of one component is 1.
It is preferably about 5 to 4.0 mm, particularly 2.0 to 3.
0 mm is more preferable. The number of annular units is preferably 3 to 10. The thickness of the annular unit in the central portion of the stent 1 is preferably about 0.05 to 0.12 mm, and particularly preferably 0.06 to 0.10 mm. The thickness of the annular unit at both ends is 0.05
Approximately 0.07 mm is suitable. The thickness of the annular unit at both ends is 3/5 to the thickness of the annular unit in the central portion.
About 4/5 is preferable.

Next, the stent 20 of the embodiment shown in FIG.
The basic configuration is the same as the stent 1 described above. The stent 20 has a substantially elliptical or polygonal constituent element 17 (17a, 1a) that is long in the axial direction and has an opening in the center.
7b, 17c, 17d, 17e), a plurality of stents 20
Are arranged so as to surround the central axis of each of the connecting parts 21 (21a, 21b, 21).
c, 21d, 21e) connected annular unit 18
(18a, 18b, 18c, 18d, 18e, 18f,
18g, 18h) and a plurality of annular units 18a, 1
8b, 18c, 18d, 18e, 18f, 18g, 18
h are arranged in the axial direction of the stent 20. Further, the connecting portion 21 of one annular unit 18 and the connecting portion 21 of the adjacent annular unit 18 are connected to each other by the connecting portions 19 (19a, 19b,
19c, 19d, 19e, 19f, 19g) are connected at one place.

Further, in this stent 20, in the space formed between the connecting portion 21 of the annular unit 18 and the two constituent elements 17 connected by the connecting portion, the constituent element 17 of the adjacent annular unit 18 is The edge is invading.
Therefore, in the stent 20, the annular units are partially overlapped when viewed in the axial direction of the stent.
For this reason, when the stent 20 is expanded, even if the individual components become shorter in the axial direction of the stent, the increase in the gap on the side surface of the stent 20 is small, and the narrowed portion of the blood vessel can be expanded more reliably. , Its maintenance will also be higher. This stent 20 also has a large number of annular units 18,
It is a tubular body configured by being connected by the connecting portion 19.

The annular unit 18 in this embodiment has five components 17a, 17b, 17c, 17d, 17e arranged so as to surround the central axis of the stent. One component is formed in a substantially rhombic shape that is long in the axial direction of the stent 20, and the center is opened in a substantially rhombic shape corresponding to the shape of the component. In addition, the components located at both ends of the stent 20 have substantially half-ends at both ends in order to ensure sufficient expansion force at the ends and to reduce damage to the indwelling vessel inner wall and the balloon. It has an elliptical shape. All components are circumferentially curved such that they are generally equidistant from the central axis of the stent.

The constituent element is connected to the center of the axial side portion of the stent 20 and the center of the axial side portion of another constituent element adjacent in the radial direction by a short connecting portion. In this example, the component 17 has two groups (17
a and 17b, 17c and 17d and 17e), the components in each group are connected by a very short connecting portion. The groups are connected by a slightly long connecting portion. Specifically, 17a and 17b are connected by a very short connecting portion 21b, and 17c and 17d are connected by
Due to the very short connection 21d, 17d and 17e are also connected by the very short connection 21e. And 17
e and 17a and 17b and 17c are slightly longer connecting portions 2
They are connected by 1a and 21c. For this reason, the intervals between all components are not uniform. Further, the shape of the constituent element is formed in a substantially rhombic shape because a void can be surely formed between the ends of the adjacent constituent elements. For this reason, a substantially V-shaped or substantially trapezoidal space is formed between the ends of the adjacent components.

Then, as shown in FIG. 8 and FIG. 9, the ends of the constituent elements of the adjacent annular units invade the voids to reduce the voids formed on the side surfaces of the stent. In this way, the constituent elements of the adjacent annular units intrude between the adjacent constituent elements of the annular unit (in the vicinity of the connecting portion), and a part of the constituent elements overlap in the axial direction of the stent. , Many annular units can be placed on a stent of a given length. In this embodiment, eight annular units are connected.

The slightly longer connecting portion 21a of the annular unit 18a and the slightly longer connecting portion 21b of the adjacent annular unit 18b are relatively long (longer than the connecting portion),
They are connected by a connecting portion 19a extending in the axial direction of the stent 20. In this embodiment, the connecting portion 19 extends slightly obliquely (about 12 °) with respect to the central axis of the stent. In other words, the stent 20 is cut in the longitudinal direction parallel to the central axis of the stent and deployed (FIG. 9).
1) in the developed state as shown in FIG.
9, with respect to the long and direction of the stent 20 is inclined at a predetermined angle of, all of the connecting portion are parallel to each other. Also in the stent 20 of this embodiment, the connecting portion 19
Are provided so that adjacent annular units 18 are connected only at one place. Further, the connecting portions 19 are arranged so as not to be continuous with the adjacent connecting portions. For this reason,
The load when one annular unit 18 changes so as to follow the deformation of the blood vessel can be suppressed from being directly (linearly) transmitted to the annular units 18 which are not adjacent to each other. Demonstrate extended functions. In the stent 20 of this embodiment, the connecting portions 19 are not continuous and are arranged in a spiral shape with an interval. Moreover, since all the connecting portions are parallel to each other, they are less likely to be twisted when the stent is expanded.

Components 17a, 17b, 17c, 17
When the stent 20 is expanded, d and 17e are deformed so that both ends are expanded in the axial direction. The components 17a, 17b, 17c, 1 are provided in order to ensure this deformation and to surely cause this deformation at both ends.
The axial end portions of 7d and 17e have smaller cross-sectional areas than the other portions. Further, as shown in FIG. 10, both end portions 20a and 20c of the stent 20 have a smaller cross-sectional area of the unit forming material than the other portion 20b. For this reason, the expansion force of the both end portions exerted when the stent 20 is expanded is lower than that of the other portions, but conversely, the followability to the bending of the blood vessel is improved, and both ends of the stent become blood vessels. Has a good affinity. Specifically, both ends 20a, 20c of the stent 20
The unit forming material is thinner than the other portion 20b. However, the width of both end portions 20a and 20c of the stent 20 is not limited to this, and may be narrower than the width of the other portion 20b.

The non-expanded diameter of the stent 20 is
About 1.2 to 1.8 mm is preferable, and especially 1.3 to
1.6 mm is more preferable. Further, the length of one annular unit, in other words, the axial length of one component is preferably about 1.5 to 4.0 mm, and particularly, 2.
0 to 3.0 mm is more preferable. Further, the number of annular units is preferably 6 to 10. Further, the length by which the constituent elements of the adjacent annular units overlap in the axial direction of the stent is preferably 0.5 to 1 mm. Further, the center-to-center distance between one constituent element and the constituent elements of the adjacent annular unit is preferably 1.3 to 2.5 mm. The length of the connecting portion is preferably 1.4 to 2.7 mm. Further, the angle of inclination of the connecting portion with respect to the central axis of the stent (the angle of inclination with respect to the longitudinal direction when viewed in a developed view) is preferably about 0 ° to 30 °, and particularly preferably 5 ° to 25 °.

Further, the thickness of the annular unit in the central portion of the stent 20 is preferably about 0.05 to 0.12 mm, and more preferably 0.06 to 0.10 mm. The wall thickness of the annular unit at both ends is from 0.05 to
About 0.07 mm is suitable. The thickness of the annular unit at both ends is 3/5 to 4 of the thickness of the annular unit in the central portion.
/ 5 is suitable. In addition, other matters, for example,
The stent forming material and the like are the same as those described above.

Next, the stent 50 of the embodiment shown in FIG.
Will be described. The stent 50 of the embodiment shown in FIG.
The basic configuration is the same as that of the stent 20 described above.
The stent 50 has a substantially elliptical or polygonal component 57 (57a, 57a, which is long in the axial direction and has an opening in the center).
57b, 57c, 57d) are plural (four), the stent 5
0 is arranged so as to surround the central axis, and the adjacent portions (side portions) of the constituent elements are connected portions 61 (61a, 61b, 6).
1c, 61d) connected annular unit 58 (58
a, 58b, 58c, 58d, 58e, 58f). A plurality of annular units 58a, 58b, 58c,
58d, 58e, and 58f are arranged in the axial direction of the stent 50. Furthermore, the connecting portion 61 of one annular unit 58
And the connecting portion 61 of the annular unit 58 adjacent to the connecting portion 5
9 (59a, 59b, 59c, 59d, 59e) are connected at one place.

Further, in this stent 50, in the space formed between the connecting portion 61 of the annular unit 58 and the two constituent elements 57 connected by the connecting portion, the constituent element 57 of the adjacent annular unit 58 is The edge is invading.
Therefore, in the stent 50, the annular units are partially overlapped when viewed in the axial direction of the stent.
Therefore, when the stent 50 is expanded, even if the individual components become shorter in the axial direction of the stent, the increase in the gap on the side surface of the stent 50 is small, and the narrowed portion of the blood vessel can be expanded more reliably. , Its maintenance will also be higher.

This stent 50 also has a large number of annular units 5.
Reference numeral 8 is a tubular body configured by being connected by the connecting portion 59. The annular unit 58, in this embodiment,
It has four constituent elements 57a, 57b, 57c, 57d arranged so as to surround the central axis of the stent. One component is formed in a substantially rhombic shape that is long in the axial direction of the stent 50, and the center is opened in a substantially rhombic shape corresponding to the shape of the component. Further, the components located at both ends of the stent 50 have substantially half-ends at both ends in order to ensure sufficient expansion force at the ends and to reduce damage to the indwelling vessel inner wall and the balloon. It has an elliptical shape. All components are circumferentially curved such that they are generally equidistant from the central axis of the stent.

In the constituent element, the center of the axial side portion of the stent 50 and the center of the axial side portion of the other constituent element adjacent in the radial direction are connected by a short connecting portion. In this example, component 57 has two groups (57
a and 57b, 57c and 57d), the components in each group are connected by a very short connecting portion. The groups are connected by a slightly long connecting portion. Specifically, 57a and 57b are connected by a very short connecting portion 61b, and 57c and 57d are connected by a very short connecting portion 61d. And 57d
And 57a and 57b and 57c are slightly longer connecting portions 61.
They are connected by a and 61c. For this reason, the intervals between all components are not uniform. Further, the shape of the constituent element is formed in a substantially rhombic shape because a void can be surely formed between the ends of the adjacent constituent elements. For this reason, a substantially V-shaped or substantially trapezoidal space is formed between the ends of the adjacent components.

Then, as shown in FIG. 12, the ends of the constituent elements of the adjacent annular units enter into this void,
It reduces the voids that form on the sides of the stent. In this way, the constituent elements of the adjacent annular units intrude between the adjacent constituent elements of the annular unit (in the vicinity of the connecting portion), and a part of the constituent elements overlap in the axial direction of the stent. , Many annular units can be placed on a stent of a given length. In this embodiment, six annular units are connected.

The slightly longer connecting portion 61a of the annular unit 58a and the slightly longer connecting portion 61b of the adjacent annular unit 58b are relatively long (longer than the connecting portion),
They are connected by a connecting portion 59a extending in the axial direction of the stent 50. In this embodiment, the connecting portion 5 9 extends to be slightly oblique (approximately 12 °) with respect to the central axis of the stent. In other words, in the developed state as shown in FIG.
Against long and direction, are inclined at a predetermined angle of, all of the connecting portion are parallel to each other.

As in the stent of FIG. 12, the connecting portions (59a, 59c, 59e) at odd positions from the distal end side are
Parallel to each other. The connection part (59
b, 59d) are parallel to each other. The even-numbered position and the odd-numbered position are not parallel to each other. Further, the odd-numbered connecting portions (59a, 59c, 59e) from the tip end side are not continuous, and are arranged in a spiral pattern with an interval, which jumps over the even-numbered connecting portions (59b, 59d). Similarly, the even-numbered connecting portions (59b, 59d) are not continuous and jump over the connecting portion (59c) located between them.
It is arranged in a spiral pattern with an interval.

Also in the stent 50 of this embodiment, the connecting portion 59 is provided so as to connect the adjacent annular units 58 only at one place. Further, the connecting portion 59 is
It is arranged so as not to be continuous with the adjacent connecting portion. Therefore, the load when one annular unit 58 changes so as to follow the deformation of the blood vessel can be suppressed from being directly (linearly) transmitted to the annular units 58 that are not adjacent to each other. Demonstrate independent extensions of. In the stent 50 of this embodiment, the connecting portions 59 are not continuous and are arranged in a spiral shape with an interval.

Components 57a, 57b, 57c, 57d
Deforms so that both ends are axially expanded when the stent 50 is expanded. In order to ensure this deformation and to surely manifest this deformation at both ends, it is assumed that the axial ends of the constituent elements 57a, 57b, 57c, 57d have a smaller cross-sectional area than the other portions. Has become. Further, both end portions 50a, 5 of the stent 50
0c has a smaller cross-sectional area of the unit forming material than the other portion 50b. For this reason, the expansion force of both end portions exerted when the stent 50 is expanded is lower than that of the other portions, but conversely, the followability to the bending of the blood vessel is improved, and both ends of the stent become blood vessels. Has a good affinity. Specifically, both ends 5 of the stent 50
In 0a and 50c, the wall thickness of the unit forming material is thinner than that of the other portion 50b. However, the width of both ends 50a, 50c of the stent 50 is not limited to this, and may be narrower than the width of the other portion 50b.

The diameter of the non-expanded stent 50 is
About 1.2 to 1.8 mm is preferable, and especially 1.3 to
1.6 mm is more preferable. Further, the length of one annular unit, in other words, the axial length of one component is preferably about 1.5 to 4.0 mm, and particularly, 2.
0 to 3.0 mm is more preferable. Further, the number of annular units is preferably 5 to 15. Further, the length in which the constituent elements of the adjacent annular units overlap in the axial direction of the stent is preferably 0.2 to 1.05 mm. In addition, the center-to-center distance between one constituent element and the constituent elements of the adjacent annular unit is preferably 2.5 to 4.0 mm. The length of the connecting portion is preferably 2,6 to 5.0 mm. Further, the angle of inclination of the connecting portion with respect to the central axis of the stent (the angle of inclination with respect to the longitudinal direction when viewed in a developed view) is preferably about 0 ° to 30 °, and particularly preferably 5 ° to 25 °.

Furthermore, the thickness of the central portion 50b of the stent 50 is preferably about 0.05 to 0.12 mm, and particularly preferably 0.06 to 0.10 mm. The thickness of both ends 50a, 50c of the stent 50 is 0.
It is preferably about 05 to 0.07 mm. The thickness of both ends 50a and 50c of the stent 50 is preferably about 3/5 to 4/5 of the thickness of the central portion 50b of the stent 50. Other matters, for example, the material for forming the stent, are the same as those described above.

Next, the method for indwelling the stent of the present invention will be described with reference to FIGS. 6, 7 and 11. The stent placement device 10 includes a stent 1, a balloon catheter 11 for expanding the stent in a blood vessel, and a protective sheath 13 accommodating the balloon catheter. The stent is fitted on the balloon 12 of the folded balloon catheter 11. In order to prevent the stent from falling off due to friction with the blood vessel as it passes through a narrow tortuous blood vessel, the entire stent is protected by a protective sheath 1
It is inserted into the blood vessel in the state of being retracted into the blood vessel 3. When advancing in the blood vessel, the guide wire 16 is inserted into the balloon catheter 11, the guide wire 16 is passed through the narrowed part of the blood vessel, and then the stent placement device 10 is placed along the guide wire 16. To proceed.
Then, after the stent indwelling device 10 together with the sheath 13 is infiltrated to the vicinity of the stenosis portion 15, the distal end of the sheath is positioned inside the stenosis portion under fluoroscopy to confirm the position, and only the sheath is retracted at that position. Next, a contrast agent is injected into the balloon 12 at high pressure, and the force expands the balloon. When the balloon is expanded, the stent is plastically deformed and expanded (expanded) so that the diameter is expanded in the radial direction, and the narrowed portion is expanded. The balloon pressure is then removed and deflated. Since the stent has an expansion holding force (shape holding force) due to plastic deformation, it does not contract but stays in that position, keeps the blood vessel expanded and improves blood flow disorders.

When the expansion force of the balloon was applied, the stent was subjected to a force to be spread in the radial direction (radial direction), and this portion was pulled because there was a connecting portion at the center of the side portion of the elliptical component. Thus, although not an exact representation, the components deform regularly and neatly into a roughly rhombic shape, as shown in FIGS. 6 and 7. When expanded, each component shortens, but shortens individually, the shortening width is negligible, and the length of the stent is hardly shortened. In the above description, the stent of the present invention has been described using a stent for expanding a vascular stenosis, but the present invention is not limited to this, and a stenosis occurs in a living body such as the bile duct, trachea, esophagus, urethra, and other organs. Can be used to improve.
The size of the stent and the size of the constituent elements are determined in consideration of the living body part to be applied.

Next, another method for placing the stent of the present invention will be described with reference to FIGS. 6, 7 and 13. The stent placement device 70 includes the stent 1 and a balloon catheter 11 for expanding the stent in a blood vessel. The stent is fitted on the balloon 12 of the folded balloon catheter 11. When advancing through the blood vessel, the guide wire 16 is inserted into the balloon catheter 11.
After passing the guide wire 16 through the narrowed portion of the blood vessel, the stent placement device 70 is advanced along the guide wire 16. Then, after the stent indwelling device 70 is inserted to the vicinity of the stenosis portion 15, the stent is positioned inside the stenosis portion under fluoroscopy. Next, a contrast agent is injected into the balloon 12 at high pressure, and the force expands the balloon. When the balloon is expanded, the stent is plastically deformed and expanded (expanded) so that the diameter is expanded in the radial direction, and the narrowed portion is expanded. The balloon pressure is then removed and deflated. Since the stent has an expansion holding force (shape holding force) due to plastic deformation, it does not contract but stays in that position, keeps the blood vessel expanded and improves blood flow disorders.

[0043]

EXAMPLES Specific examples of the stent of the present invention will be described. (Example 1) A stainless steel (SUS316L) having a diameter of 1.4 mm and a wall thickness of 0.10 mm has a length of 50 mm.
A metal pipe cut into pieces was used. As a method of manufacturing the present stent, a method of hollowing out the stent portion from a metal pipe was used. Various methods are conceivable for hollowing out the stent from the pipe. For example, there are an etching method using masking and chemicals called photofabrication, an electric discharge machining method using a mold, and a mechanical cutting machining method. Here, the laser processing method was used as the simplest method with high processing accuracy. As a laser processing machine, N
An EC YAG laser (trade name SL116E) was used. The metal pipe was set on a jig with a rotary motor equipped with a chuck mechanism so that the shaft would not move, and this was set on an XY table capable of numerical control. And XY
The table and the rotary motor were connected to a personal computer, and the output of the personal computer was input to the numerical controller and rotary motor of the XY table. Drawing software is stored in the personal computer, and a development drawing of the stent having the composition as shown in FIG. 5 is input therein.

With such a configuration, the XY table and the rotary motor are driven based on the drawing data output from the personal computer. By irradiating it with a laser, a stent structure having a shape as shown in FIG. 1 was prepared. A mandrel was inserted in the pipe to prevent the laser light from penetrating the pipe. As a laser processing condition for the metal pipe, a current value of 25
A, output 1.5 W, drive speed 10 mm / min. Note that the system is not limited to the above-described system, and a so-called laser marker (galvanometer system) driven by a laser processing machine may be used. Then, about 9 chemical polishing liquids for stainless steel (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunbit 505, containing a mixed liquid of hydrochloric acid and nitric acid as a basic component and an organic sulfur compound and a surfactant added)
Only the annular unit portion at one end of the above-mentioned stent structure was immersed in what was heated at 8 ° C. for about 5 minutes. Similarly, the annular unit at the other end is similarly treated with the above processing liquid,
It was immersed for about 5 minutes. As a result, the thickness of the annular units at both ends of the stent was made thinner than the other annular units.

In this way, the stent of the present invention having the shape shown in FIGS. 1 to 3 was prepared. The constituent elements of the produced stent are elliptical, with the major axis having a length of 2.6 mm and the minor axis having a length of 0.72 mm, which are arranged linearly with a gap of 0.2 mm in the axial direction. I'm out.
The total length of the stent in the axial direction is 16.6 mm, and the length of the connecting portion that connects the constituent elements in the circumferential direction is 0.38 m.
m, and the length of the connecting portion connecting the annular units is
The width was 2.8 mm and the width was 0.2 mm. The width of the constituent element was 0.2 mm, and the width near both ends (bending points) in the axial direction was 0.17 mm. Further, the cross-sectional area of most of the constituent elements was 0.02 mm ² , and the cross-sectional area near both ends (bending points) in the axial direction was 0.014 mm ² . Further, the thickness of the constituent material of the annular unit in the central portion was 0.1 mm, and the thickness of the constituent material of the annular unit at both ends was 0.08 mm. The outer diameter of the stent (annular unit) was 1.4 mm.

Then, a balloon catheter was inserted into the stent, an X-ray contrast medium was pressed into the balloon lumen at a pressure of 10 kg / cm ² , and the balloon was inflated, whereby the stent expanded substantially evenly. The outer diameter of the expanded stent was 3.2 mm. At this time, the major axis of the elliptical component is shortened from 2.6 mm to about 1.6 mm, the minor axis 0.72 mm is extended to 2.1 mm, and the major axis and minor axis lengths are reversed, As shown in FIGS. 6 and 8, the shape was changed to a substantially rhombic shape. However, since the annular units are connected by a long connecting portion parallel to the axial direction, the total length of the stent is hardly shortened. The shortened part is only the amount that the annular units at both ends of the stent are shortened, and since the elliptical major axis 2.6 mm becomes 1.6 mm, half the difference of 1 mm, 0.5 mm, is shortened at one end of the stent. 1mm will be shortened. This is the total length of the stent 1
It was only 6% of 6.5 mm, which was a level that had no problem in actual clinical practice.

Example 2 Up to laser processing was carried out in the same manner as in Example 1 to prepare a stent structure. And
The two annular unit portions from one end of the above-mentioned stent structure were immersed for about 5 minutes in the above-mentioned chemical polishing liquid for stainless steel heated to about 98 ° C. Similarly, the two annular units at the other end were also immersed in this chemical polishing liquid for about 5 minutes. Further, only the annular unit portion at one end was immersed for about 3 minutes. Similarly, only the annular unit at the other end was further immersed in the above chemical polishing liquid for about 3 minutes. As a result, the two annular units in the central portion of the stent had the largest wall thickness, the annular units at both ends had the smallest wall thickness, and the annular units between them had an intermediate wall thickness.

(Example 3) Stainless steel (SUS316)
A metal pipe obtained by cutting L) having a diameter of 1.4 mm and a wall thickness of 0.10 mm into a length of 50 mm was used. As a method for manufacturing the present stent, a method of hollowing out a portion of the stent from a metal pipe by laser processing was used. As the laser processing machine, a YAG laser (trade name SL116E) manufactured by NEC was used. The metal pipe was set on a jig with a rotary motor equipped with a chuck mechanism so that the shaft would not move, and this was set on an XY table capable of numerical control. Then, the XY table and the rotary motor were connected to a personal computer, and the output of the personal computer was input to the numerical controller of the XY table and the rotary motor. Drawing software is stored in the personal computer, and a development drawing of a stent having a composition as shown in FIG. 9 is input therein.

With such a configuration, the XY table and the rotary motor are driven based on the drawing data output from the personal computer. By irradiating it with a laser, a stent structure having a shape as shown in FIG. 8 was prepared. A mandrel was inserted in the pipe to prevent the laser light from penetrating the pipe. As a laser processing condition for the metal pipe, a current value of 25
A, output 1.5 W, drive speed 10 mm / min. Then, a chemical polishing liquid for stainless steel (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunbit 505, containing a mixed liquid of hydrochloric acid and nitric acid as a basic component and an organic sulfur compound and a surfactant added) at about 98 ° C. One end portion (one and a half annular unit, 20a portion) of the above stent structure was immersed in the heated material for about 5 minutes. Similarly, the other end (one and a half annular unit, 20c portion) was similarly immersed in the treatment liquid for about 5 minutes. As a result, the thickness of both ends of the stent was made thinner than the other annular units.

In this way, the stent of the present invention having the shape shown in FIG. 9 was prepared. The constituent elements of the produced stent are substantially rhombic, and only the end portions of the constituent elements located at both ends are semielliptical. The component has a major axis (longer on the diagonal line) of 2.6 mm, a shorter axis (shorter on the diagonal line) of 0.6 mm, and the length of the connecting portion connecting the components in the circumferential direction. Has a short connection length of 0.2
5 mm, the length of the long connecting portion is 0.4 mm,
The width of the constituent element was 0.2 mm, and the width near both ends (bending points) in the axial direction was 0.17 mm. The cross-sectional area of most of the components is 0.02 mm.
² and the cross-sectional area near both ends (bending points) in the axial direction is
It was 0.015 mm ² . One annular unit was formed by six components and five connections (three short connections and two long connections).

Between the adjacent constituent elements of the annular unit (in the vicinity of the connecting portion), the constituent elements of the adjacent annular unit intrude, and 0.7 mm overlaps in the axial direction of the stent. It was in the state of connecting eight. In addition, the center-to-center distance between one constituent element and the constituent element of the adjacent annular unit was 1.9 mm. The length of the connecting portion that connects the annular units is 2.0 mm,
The width was 0.2 mm, and the inclination angle with respect to the central axis of the stent was 12 °. Furthermore, the central part 2 of the stent
The thickness of the constituent material of 0b is 0.1 mm, and the thickness of the constituent material of both ends (20a, 20c) is 0.08 mm.
Met. The outer diameter of the stent (annular unit) is 1.4
It was mm.

Then, a balloon catheter was inserted into the stent, an X-ray contrast medium was pressed into the balloon lumen at a pressure of 10 kg / cm ² , and the balloon was inflated, so that the stent expanded substantially evenly. The outer diameter of the expanded stent was 3.0 mm. At this time, the long axis of the component is shortened from 2.6 mm to about 1.5 mm, the short axis of 0.6 mm is extended to 1.7 mm, and the lengths of the long axis and the short axis are reversed and further opened. It was transformed into a rhombus shape. However, since the annular units are connected to each other by long and substantially parallel connecting portions, the total length of the stent is hardly shortened. The part to be shortened is only the amount that the annular units at both ends of the stent are shortened, and the elliptical long axis 2.6 mm is 1.
Since it is 5 mm, the difference of 1.1 mm is half 0.55 mm
Is shortened at one end of the stent and 1.1 mm at both ends of the stent
Will be shortened. This was only 6% of the total stent length of 16 mm, which was a level that had no problem in actual clinical practice.

(Example 4) Stainless steel (SUS316)
A metal pipe obtained by cutting L) having a diameter of 1.4 mm and a wall thickness of 0.08 mm into a length of 50 mm was used. As a method for manufacturing the present stent, a method of hollowing out a portion of the stent from a metal pipe by laser processing was used. As the laser processing machine, a YAG laser (trade name SL116E) manufactured by NEC was used. The metal pipe was set on a jig with a rotary motor equipped with a chuck mechanism so that the shaft would not move, and this was set on an XY table capable of numerical control. Then, the XY table and the rotary motor were connected to a personal computer, and the output of the personal computer was input to the numerical controller of the XY table and the rotary motor. Drawing software is stored in the personal computer, and a development drawing of a stent having a composition as shown in FIG. 12 is input therein.

With such a configuration, the XY table and the rotary motor are driven based on the drawing data output from the personal computer. The stent structure was created by irradiating it with a laser. A mandrel was inserted in the pipe to prevent the laser light from penetrating the pipe. The laser processing conditions for the metal pipe were a current value of 25 A, an output of 1.5 W and a driving speed of 10 mm / min.

In this way, the stent of the present invention was prepared. The constituent elements of the produced stent are substantially rhombic, and only the end portions of the constituent elements located at both ends are semielliptical. The constituent elements have a major axis (longer diagonal line) of 3.8 mm and a shorter axis (shorter diagonal line) of 0.65.
mm, the length of the connecting portion connecting the components in the circumferential direction is such that the length of the short connecting portion is 0.3 mm, the length of the long connecting portion is 0.6 mm, Width is 0.1
The width was 5 mm, and the width in the vicinity of both ends (bending points) in the axial direction was 0.25 mm. The cross-sectional area of most of the constituent elements was 0.012 mm ² . An annular unit was formed by the four components and the four connections (two short connections and two long connections).

Between the adjacent constituent elements of the annular unit (in the vicinity of the connecting portion), the constituent elements of the adjacent annular unit intrude, and 0.7 mm overlaps in the axial direction of the stent. There were 6 connected. In addition, the center-to-center distance between one constituent element and the constituent elements of the adjacent annular unit was 3.1 mm. The length of the connecting portion that connects the annular units is 3.2 mm,
The width was 0.15 mm, and the inclination angle with respect to the central axis of the stent was 12 °.

Then, a balloon catheter was inserted into the stent, an X-ray contrast medium was pressed into the balloon lumen at a pressure of 10 kg / cm ² , and the balloon was inflated, whereby the stent was expanded substantially uniformly. The outer diameter of the expanded stent was 3.0 mm. At this time, the major axis of the component is shortened from 3.8 mm to about 2.5 mm, the minor axis 0.65 mm is extended to 2.9 mm, and the major axis and minor axis lengths are reversed and opened more. It was transformed into a rhombus shape. However, since the annular units are connected to each other by long and substantially parallel connecting portions, the total length of the stent is hardly shortened. The shortened part is only the amount that the annular units at both ends of the stent are shortened, and the elliptical major axis 3.8 mm becomes 2.5 mm.
mm shortened at one end of the stent and 1.3 at both ends of the stent
mm will be shortened. This has a total stent length of 19.
It was only 6% of 3 mm, which was a level that was not problematic in actual clinical practice.

[0058]

INDUSTRIAL APPLICABILITY The stent of the present invention is formed in a substantially tubular body, has a diameter for insertion into a living body, and expands when a force that spreads radially outward from the inside of the tubular body is applied. A possible stent, wherein the stent comprises a plurality of substantially elliptical or polygonal constituent elements that are long in the axial direction of the stent and open at the center, and are arranged so as to surround the central axis of the stent, and Each adjacent part of the element is composed of an annular unit connected by a connecting part, and a plurality of the annular units are arranged in the axial direction of the stent, and further, the connecting part of one annular unit is adjacent to the annular unit. The connecting portion and at least one place are connected by the connecting portion.

For this reason, since the constituent elements which are substantially elliptical or substantially polygonal and each have an independent closed system with an opening at the center are connected in the circumferential direction to form an annular unit, strong expansion holding is achieved. Exert strength. In addition, the center of the axial side portion of the stent of one component and the center of the axial side portion of the other component adjacent in the radial direction are connected by a short connecting portion, and the stent is expanded. However, since the connection portion does not substantially change, the force during expansion tends to be applied to the center of each component, and each component can be uniformly expanded. Then, the connecting portion of one annular unit and the connecting portion of the adjacent annular unit are connected by a connecting portion extending in the axial direction of the stent, and this connecting portion also does not substantially change even when the stent is expanded. As a result of the expansion of the stent, the total length of the stent is almost unchanged.

Further, the end portion of the constituent element of the adjacent annular unit enters into the space formed between the connecting portion of the annular unit and the two constituent elements connected by the connecting portion. If they are, the annular units will partially overlap when viewed in the axial direction of the stent, and when the stent is expanded, even if individual components become shorter in the axial direction of the stent, In this case, the increase in the gap in the area is small, the narrowed portion of the blood vessel can be expanded more reliably, and the maintenance thereof is also higher.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the stent of the present invention.

FIG. 2 is a front view of the stent shown in FIG.

3 is a partially omitted cross-sectional view of the stent shown in FIG.

FIG. 4 is a side view of the stent shown in FIG.

FIG. 5 is a developed view of the stent shown in FIG. 1 before expansion.

FIG. 6 is a front view when the stent shown in FIG. 1 is expanded.

FIG. 7 is a developed view of the stent after expansion.

FIG. 8 is a front view of a stent according to another embodiment of the present invention.

9 is a developed view of the stent shown in FIG. 8 before expansion.

10 is a partially omitted cross-sectional view of the stent shown in FIG.

FIG. 11 is an explanatory diagram for explaining a state of inserting a stent.

FIG. 12 is a developed view of a stent according to another embodiment of the present invention before expansion.

FIG. 13 is an explanatory diagram for explaining a state of inserting a stent.

[Explanation of symbols]

1 Stent 2,2a, 2b, 2c, 2d Component 3,3a, 3b, 3c, 3d Connection part 4,4a, 4b, 4c, 4d, 4e, 4f Annular unit 5,5a, 5b, 5c, 5d, 5e Connecting part 20 Stent

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-2-174859 (JP, A) JP-A-6-181993 (JP, A) JP-A-6-292730 (JP, A) JP-A-8- 738 (JP, A) US Patent 5449733 (US, A) International Publication 95/31945 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61M 29/00-29/02 A61F 2 / 06

Claims (14)

(57) [Claims] 1. A stent formed into a substantially tubular body, having a diameter for insertion into a living body, and expandable when a force spreading radially outward from the inside of the tubular body is applied. The stent has a plurality of substantially elliptical or polygonal constituent elements that are long in the axial direction of the stent and open in the center, and are arranged so as to surround the central axis of the stent, and each adjacent part of the constituent elements is A plurality of annular units are arranged in the axial direction of the stent, and the connecting units of one annular unit are adjacent to the connecting units of adjacent annular units. A stent for indwelling a living body, characterized in that it is connected at least at one place by 2. The indwelling device according to claim 1, wherein the stent has at least three annular units in the axial direction, and the annular units at both ends are thinner than other annular units. For stent. 3. A width in the vicinity of a bending point located at both ends in the axial direction of the substantially elliptical or polygonal component.
Is narrower than other portions.
The stent for indwelling a living body according to 1. 4. The stent according to claim 1, wherein the stent has at least three axial units in the axial direction, and the annular units at both ends have a smaller cross-sectional area of a unit forming material than other annular units. The stent for indwelling a living body according to the above. 5. A wall thickness in the vicinity of a bending point located at both axial ends of the substantially elliptical or polygonal component.
Is thinner than other portions.
The stent for indwelling a living body according to 1. 6. The indwelling stent according to claim 1, wherein only one connecting portion is formed between adjacent annular units. 7. The indwelling stent for living body according to claim 1, wherein the connecting portion is arranged so as not to be continuous with an adjacent connecting portion. 8. The indwelling stent according to claim 7, wherein the connecting portion is arranged in a spiral shape when viewed from the entire stent. 9. The indwelling stent according to claim 1, wherein the stent is annealed. 10. The components are arranged at substantially equal angular intervals with respect to the central axis of the stent.
10. The stent for indwelling a living body according to any one of 1 to 9. 11. In the stent, the substantially elliptical or polygonal constituent elements are aligned substantially linearly with respect to the axial direction of the stent, and the connecting portion is substantially aligned with the axial direction of the stent. The indwelling stent according to any one of claims 1 to 10, which are parallel to each other. 12. An end portion of the component of an adjacent annular unit is inserted into a space formed between the connecting portion of the annular unit and two components connected by the connecting portion. The stent for indwelling a living body according to any one of claims 1 to 9. 13. The connecting portion is inclined with a predetermined accuracy with respect to the longitudinal direction of the stent when the stent is cut in a longitudinal direction parallel to the central axis of the stent and deployed, The stent for indwelling a living body according to any one of claims 1 to 12. 14. The constituent element is formed in a substantially rhombic shape that is long in the axial direction of the stent, and the constituent elements located at both ends of the stent have substantially semi-elliptical ends located at the outer sides. The stent for indwelling a living body according to any one of claims 1 to 13, which is a thing.