JP2021153995A - In vivo indwelling stent and stent delivery system - Google Patents

Abstract

To provide a stent that can be re-stored after a certain amount of discharge and has a favorable radial compressibility and expansive force, and biological organ dilator.SOLUTION: A stent 1 includes annular bodies 2a, 2b, 2c, 2d, 2e and 2f formed of linear components having one-end side bent portions 21 and 22 and other-end side bent portions 30, where an apex of two adjacent other-end side bent portions 30 is connected by one one-end side bent portion 22 and a V-shaped connecting portion 4 of adjacent annular bodies. The stent 1 does not have the other-end side bent portions 30 becoming free ends excluding an annular body 2f located at the other end of the stent 1, and the respective annular bodies 2a, 2b, 2c, 2d, 2e and 2f include a plurality of one-end side bent portions 21 becoming free ends 21a.SELECTED DRAWING: Figure 1

Description

The present invention relates to an in vivo indwelling stent and a stent delivery system used for improving a stenosis or an obstruction formed in a living lumen such as a blood vessel, a bile duct, a trachea, an esophagus, or a urethra.

In vivo stents are used to treat a variety of disorders caused by the narrowing or obstruction of blood vessels or other in vivo lumens. The stent is formed in a tubular shape to dilate the site of stenosis or occlusion and to secure its lumen.
Hereinafter, blood vessels will be described as an example, but the present invention is not limited thereto.
Since a stent is inserted into the body from outside the body, it has a small diameter at the time of insertion, and is a stent that expands at a target stenosis or occlusion site to increase the diameter and retains the lumen as it is.
The stent is generally a metal wire or a cylindrical one obtained by processing a metal tube. It is attached to a catheter or the like in a thin state, inserted into a living body, expanded by some method at a target site, and adhered to and fixed to the inner wall of the lumen to maintain the shape of the lumen.
Stents are classified into self-expandable stents and balloon dilated stents according to their function and placement method. The balloon expansion type stent does not have an expansion function in the stent itself, and after inserting the stent mounted on the balloon into the target site, the balloon is expanded and the stent is expanded (plastically deformed) by the expansion force of the balloon to expand the target lumen. Fix it in close contact with the inner surface. This type of stent requires the above-mentioned stent expansion work. On the other hand, a self-expandable stent is a stent itself that has an expanding function. It is inserted into the living body as a thinly contracted state, and by opening it at the target site, it returns to its original expanded state and the inner wall of the lumen. It adheres to and is fixed to maintain the shape of the lumen.

The purpose of current stent placement is to restore blood vessels that have been stenotic for some reason to their original patency. Most of the self-expandable stents are used in the peripheral area such as blood vessels and carotid arteries of the lower limbs, and in the coronary area, Boston Scientific's Radius stent has been introduced to the market in the past. This stent has a form as shown in Japanese Patent Application Laid-Open No. 11-505441 (Patent Document 1). It has been reported that this type of stent is difficult to position at the time of placement due to its nature, and a so-called jumping phenomenon occurs in which the stent moves excessively from the sheath and is placed.

As a self-expandable stent, those shown in Japanese Patent Application Laid-Open No. 2003-93519 (Patent Document 2) have been proposed.
The stent disclosed in Patent Document 2 is defined by connecting a plurality of wavy struts extending axially from one end side to the other end side of the stent and arranged in the circumferential direction of the stent and adjacent wavy struts. It is provided with a plurality of connecting struts extending in the long axis direction, and the end portion of the wavy strut is connected to the end portion of the adjacent wavy strut. It is flexible because it is composed of a plurality of wavy struts extending in the axial direction of the stent in this way.

Further, as the self-expandable stent, the actual fair 6-5800 (Patent Document 3) and the actual fair 5-111880 (Patent Document 4) include a plurality of one-sided bent portions having an apex on one end side in the axial direction. An annular body formed of a wavy and annular wire rod having a plurality of bending portions on the other end side having vertices on the other end side in the axial direction of the stent is arranged in a plurality of axial directions, and adjacent annular bodies are arranged. A tubular in vivo indwelling stent connected by a connecting portion connected to the apex of the bending portion on the other end side is disclosed. This stent can be re-stored after being discharged to some extent.

Special Table No. 11-505441 Japanese Patent Application Laid-Open No. 2003-93519 Real fairness 5-11880 Real fairness 6-5800

However, in Patent Document 2, the connecting strut extends in the axial direction while being curved. As a result of research by the present inventors, it was found that in the stent of Patent Document 2, since the connecting strut is curved so as to extend in the axial direction of the stent, the deformability at the time of radial compression is not sufficient.
Further, in Patent Document 3, the wire wire 4 which is the connecting portion is continuously linearly continuous in the axial direction of the stent, which may hinder the flexibility of the stent, and the wire wire is a bent portion. Since it is connected to the apex of the bent portion and passes through the inside of the bent portion, it hinders the inward deformation of the bent portion and the radial compressibility is not sufficient.
Further, in Patent Document 4, since there is no bent portion which is a free end other than both side portions of the stent, the expanding force of the stent is not sufficient.

Therefore, an object of the present invention is to provide a wavy and annular shape having a plurality of one-end bending portions having an apex on one end side in the axial direction and a plurality of other-end bending portions having an apex on the other end side in the axial direction of the stent. A tubular in-vivo indwelling stent in which the annular bodies formed by the linear components of the above are arranged in a plurality of axial directions and the adjacent annular bodies are connected by a connecting portion, and the stent is a stent after discharge to some extent. Provided are an in vivo indwelling stent and a biological organ dilating device that can be re-stored and have good radial compressibility and sufficient dilating force.

Those that achieve the above objectives are as follows.
(1) A wavy and annular linear configuration including a plurality of bent portions on one end side having an apex on one end side in the axial direction and a plurality of bent portions on the other end side having an apex on the other end side in the axial direction of the stent. The annular body formed by the element is a tubular in vivo indwelling stent in which the annular bodies formed by the elements are arranged in a plurality of axial directions and the adjacent annular bodies are connected to each other.
In the annular body other than the annular body located at the other end of the stent, the apex of all two adjacent other end side bending portions of each annular body is one one end of the adjacent annular body. The side bend and the V-shaped connecting portion are connected, and the adjacent annular bodies are connected by a plurality of the V-shaped connecting portions, and the stent is further attached to the other end of the stent. Except for the located annular body, each of the annular bodies does not have the other end side bent portion having a free end at the apex, and each of the annular bodies includes a plurality of the one end side bent portions having a free end at the apex. Stent for indwelling.

(2) The in vivo indwelling stent according to (1) above, wherein the bent portion on one end side of the stent is arranged so as to be substantially linear in the axial direction of the stent.
(3) The in vivo indwelling stent according to (1) or (2) above, wherein the bent portion on the other end side of the stent is arranged so as to be substantially linear in the axial direction of the stent.
(4) The stent is for in-vivo placement according to any one of (1) to (3) above, wherein an intersection is formed by the V-shaped connecting portion and the bending portion on one end side connected to the V-shaped connecting portion. Stent.
(5) Any of the above (1) to (4), wherein the annular body excluding the annular body located at the other end of the stent has the same number of the one end side bent portions and the same number of the other end side bent portions. In vivo indwelling stent described in Crab.
(6) The annular body excluding the annular body located at one end of the stent alternates between a long bending portion on one end side having a long bending portion and a short bending portion on one end side having a shorter bending portion than the long bending portion on one end side. The in vivo indwelling stent according to any one of (1) to (5) above.
(7) The in-vivo indwelling stent according to (6) above, wherein the one-sided long bending portion and the one-one-side short bending portion of the stent are arranged substantially linearly and alternately in the axial direction of the stent.
(8) The two end side ends of the V-shaped connecting portion are connected to the vertices of the two bent portions on the other end side, and the other end side of the V-shaped connecting portion is short on the one end side. The in vivo indwelling stent according to (6) or (7) above, which is connected to the apex of the bent portion.
(9) The stent is formed by a plurality of the V-shaped connecting portions and the other end side bent portions connected thereto, and a plurality of first inclined lines inclined in a first direction with respect to the central axis of the stent. The shape portion, a plurality of second inclined linear portions inclined in a second direction different from the inclined direction of the first inclined linear portion with respect to the central axis of the stent, and the first inclined linear portion and the said portion. The in-vivo indwelling stent according to any one of (1) to (8) above, which has a linear network structure formed by an intersection with a second inclined linear portion.
(10) In the stent, the one end side bent portion is located in each mesh of the linear mesh structure, and the two other end side ends of the one end side bent portion form the respective meshes. It is connected to the vicinity of the central portion of the two other-side linear components, and each mesh is divided into a substantially square hollow portion and a substantially "<" -shaped hollow portion by the one end side bending portion. The in vivo indwelling stent according to (9) above.
(11) Any of the above (1) to (10), wherein the plurality of bent portions on the other end side of the annular body are substantially located on one circumference orthogonal to the central axis of the stent. In vivo indwelling stent according to.
(12) The in-vivo indwelling according to any one of (1) to (11) above, wherein the number of bent portions on one end side in the annular body excluding the annular body located at the other end of the stent is an even number. Stent.
(13) The stent is the number of linear components existing in a cross section orthogonal to the central axis of the stent in a portion other than the annular body located at one end of the stent and the annular body located at the other end. Is the in vivo indwelling stent according to any one of (1) to (12) above, which is almost the same.
(14) The stent is formed in a substantially cylindrical shape, is compressed in the central axial direction when inserted into a living body, and expands outward when placed in a living body to restore the shape before compression. The in vivo indwelling stent according to any one of (13).

In addition, those that achieve the above objectives are as follows.
(15) The sheath, the stent of (14) housed in the tip of the sheath, and an inner tube for slidably inserting the inside of the sheath and pushing out the stent from the tip of the sheath are provided. Stent delivery system.

The in vivo indwelling stent of the present invention has a wavy shape including a plurality of one-sided bending portions having an apex on one end side in the axial direction and a plurality of other end-side bending portions having an apex on the other end side in the axial direction of the stent. The annular body formed by the annular linear component is arranged in a plurality of axial directions, and the adjacent annular bodies are connected to each other to form a tubular in vivo indwelling stent. A stent is an annulus other than an annulus located at the other end of the stent, with the apex of all two adjacent end-side bends of each annulus being V with one one end bend of the adjacent annulus. The annulus is connected by a character-shaped connecting part, and the adjacent ring-shaped bodies are connected by a plurality of V-shaped connecting parts, and the stent has an apex except for the ring-shaped body located at the other end of the stent. Each annular body does not have a free end bent at the other end, and each annular body has a plurality of bent ends at the free end.
In particular, the vertices of all two adjacent end-side bends of each ring are connected to one end-side bend of the adjacent ring by a V-shaped connecting portion, and the outermost ring is formed. Other than that, since it does not have a bent portion on the other end side where the apex is a free end, the stent can be re-stored after a certain amount of discharge. Further, by having an intersection formed by a V-shaped connecting portion and a bent portion on one end side connected to the V-shaped connecting portion, good radial deformability is provided. In addition, the stent has a large number of one-sided bends that maintain the free end, thus providing sufficient dilation force.

FIG. 1 is a development view of an in-vivo indwelling stent according to an embodiment of the present invention at the time of manufacture. FIG. 2 is a partially enlarged view of the in vivo indwelling stent of FIG. FIG. 3 is a developed view of the in vivo indwelling stent of FIG. 1 when compressed. FIG. 4 is an explanatory view of the in vivo indwelling stent of FIG. FIG. 5 is a front view of the stent delivery system according to the embodiment of the present invention. FIG. 6 is an enlarged view of a partial breakage of the tip of the stent delivery system shown in FIG.

The in vivo indwelling stent of the present invention will be described with reference to the examples shown in the drawings.
The in-vivo indwelling stent 1 of the present invention has a plurality of one-end bent portions 20, 21 and 22 having vertices on one end side in the axial direction, and a plurality of other ends having vertices on the other end side in the axial direction of the stent 1. The annular bodies 2a, 2b, 2c, 2d, 2e, and 2f formed by the wavy and annular linear components having the side bent portion 30 are arranged in a plurality of axial directions, and the annular bodies 2a, 2b adjacent to each other are arranged in a plurality of axial directions. , 2c, 2d, 2e, 2f are connected to each other to form a tubular in vivo stent.

The stent 1 is an annular body 2a, 2b, 2c, 2d, 2e excluding the annular body 2f located at the other end of the stent 1, in which all two adjacent bodies 2a, 2b, 2c, 2d, 2e are adjacent to each other. The apex of the end-side bent portion 30 is one end-side bent portion 22 and a connecting portion 4 of adjacent annular bodies 2b, 2c, 2d, 2e, 2f (annular bodies adjacent to each other in the axial direction and located on the other end side). Are connected by. Then, the adjacent annular bodies 2a, 2b, 2c, 2d, 2e, and 2f are connected by a plurality of connecting portions 4. Further, the stent 1 does not have the other end side bent portion 30 whose apex is a free end, except for the annular body 2f located at the other end of the stent 1, and each annular body 2a, 2b, 2c, 2d, 2e. , 2f include a plurality of one-end side bent portions 21 in which the apex 21a is a free end.
This stent 1 can be effectively used as a stent for dilation of a cerebral artery.

The stent 1 of this embodiment is a so-called self-expanding stent which is formed in a substantially cylindrical shape, is compressed in the central axial direction when inserted into a living body, and expands outward when placed in a living body to restore the shape before compression. ..
As shown in FIGS. 1 to 3, the stent 1 of this embodiment is arranged in parallel in the axial direction so that a plurality of annular bodies 2a, 2b, 2c, 2d, 2e, and 2f are adjacent to each other in the axial direction. , Adjacent ring bodies are connected. Each of the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f has a plurality of one-sided bent portions 20, 21, 22 having vertices on one end side in the axial direction, and apex on the other end side in the axial direction of the stent 1. It is formed of a wavy and annular linear component having a plurality of bent portions 30 on the other end side.

As shown in FIG. 1, the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f in the stent 1 of this embodiment have a plurality of one-end bent portions 20, 21, 22, and other end-side bent portions having substantially the same pitch. It has 30. The number of the bent portions 20, 21 and 22 (or the bent portions 30 on the other end side) of each of the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f is preferably 4 to 10.

Each of the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f has a plurality of one-sided bending portions 20, 21, 22 having vertices on one end side in the axial direction of the stent 1, and other than the axial direction of the stent 1. It is provided with a plurality of other end side bent portions 30 having vertices on the end side, and a plurality of V-shaped connecting portions 4 for connecting the two other end side bent portions 30 and one one end side bent portion 22. The V-shaped connecting portion 4 is also formed by linear components.

In the stent 1 of this embodiment, in each of the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f, one end side bending portions 20, 21 and 22 located on one end side of the stent are substantially linear in the axial direction of the stent. The bent portion 30 on the other end side is also arranged so as to be substantially linear in the axial direction of the stent.

Then, the stent 1 has all the adjacent 2a, 2b, 2c, 2d, 2e of the annular bodies 2a, 2b, 2c, 2d, 2e in the annular bodies 2a, 2b, 2c, 2d, 2e except the annular body 2f located at the other end of the stent 1. The apex of the other end side bent portion 30 is connected to the apex of one one end side bent portion 22 of the adjacent annular bodies 2b, 2c, 2d, 2e, 2f by a V-shaped connecting portion 4.

Further, adjacent annular bodies 2a, 2b, 2c, 2d, 2e, 2f are connected by a plurality of connecting portions 4 (V-shaped connecting portions 4), and the stent 1 is attached to the other end of the stent 1. Except for the annular body 2f located, the other end side bending portion 30 having a free bending end is not provided, and each of the annular bodies 2a, 2b, 2c, 2d, 2e, 2f has a plurality of one ends having a free bending end 21a. A side bending portion 21 is provided. The annular body 2f located at the other end has a plurality of bent portions 31 on the other end side having free bending ends.

The annular bodies 2a, 2b, 2c, 2d, and 2e excluding the annular body 2f located at the other end of the stent 1 are provided with the same number of one-end side bent portions 20, 21, 22 and the same number of other end-side bent portions 30. ing. It should be noted that the number of the one-sided bent portions 21 and 22 and the other-ended bent portion 31 in the annular body 2f located at the other end is larger than the number of the one-ended side bent portion and the other-ended bent portion in the annular body other than the annular body 2f. It may be.

Then, in the stent 1, the annular bodies 2b, 2c, 2d, 2e, and 2f excluding the annular body 2a located at one end of the stent 1 are formed from the one end side long bending portion 21 having a long bending portion and the one end side long bending portion 21. The short bent portions 22 on one end side, which have short bent portions, are provided so as to alternate. Therefore, the annular bodies 2b, 2c, 2d, 2e, and 2f have a plurality of vertices and have different heights of adjacent vertices.
The axial length of the one end side short bent portion 22 is preferably 9/10 to 3/10 of the axial length of the one end side long bent portion 21, and is particularly 3/4 to 1/2. Is preferable.

Each end side length bent portion 21 has substantially the same height (bent portion length). The short bent portion 22 on one end side has substantially the same height (bending portion length). Further, in the stent 1, the long bending portion 21 on the one end side and the short bending portion 22 on the one end side are arranged substantially linearly and alternately in the axial direction of the stent 1. In particular, in this embodiment, the short bent portion 22 on the one end side is arranged on the other end side of the long bent portion 21 on the one end side, and both are connected to each other.

In the stent 1 of this embodiment, the annular body 2a has only one end side bending portion 20 having the same bending portion length as the one end side bending portion. In particular, in this embodiment, the annular body 2a at one end includes only a single short bending portion 20 on one end side having a relatively short bending length. The annular body 2a at one end may include a long bending portion 21 at one end and a short bending portion 22 at one end, as in the annular body described above, or includes only the long bending portion 21 at one end. It may be a thing.

Next, the connecting portion 4 (V-shaped connecting portion 4) will be described with reference to FIG.
In the stent 1 of this embodiment, the vertices of all two adjacent other end bending portions 30 of the respective annulus 2a, 2b, 2c, 2d, 2e are adjacent annulus 2a, 2b, 2c, 2d, 2e. , 2f is connected to one end-side bent portion 22 by a connecting portion 4 (V-shaped connecting portion 4).

One end side ends of the two linear components 41 and 42 of the connecting portion 4 (V-shaped connecting portion 4) are connected to the vertices of the two other end side bent portions 30. As a result, the other end side bent portion 30 becomes the other end side bent portion having no free end, although maintaining the bent portion. Further, the connecting portion between the bent portion 30 on the other end side and the linear components 41 and 42 of the V-shaped connecting portion 4 is a Y-shaped connecting portion.
Further, the other end side end portion 43 of the V-shaped connecting portion 4 is connected to the apex 22a of the one end side short bending portion 22. The other end side end 43 of the V-shaped connecting portion 4 and the apex 22a of the one end side short bending portion 22 are integrated by being connected. The portion where the other end side end 43 of the V-shaped connecting portion 4 and the apex 22a of the one end side short bending portion 22 are integrated is wider than the linear component of the other portion. The width of the integrated portion is preferably 1.5 to 2.5 times the width of the linear component of the other portion.

The connecting portion 4 is composed of two linear components, one end of which is connected to the apex of the adjacent other end side bending portion 30 of one annular body, and the other end of each is the above-mentioned. It may be connected to the apex 22a of the same one-end side short bending portion 22 of the annular body having one end connected and the annular body adjacent to each other in the axial direction. Even in such a case, a V-shaped connecting portion is formed in cooperation with the apex 22a of the short bending portion 22 on one end side.
In the stent 1, an X-shaped intersection is formed by the V-shaped connecting portion 4 and the one-end side bent portion 22 connected to the V-shaped connecting portion 4. Therefore, although the bent portion is maintained, the bent portion that is a free end does not exist in the connecting portion. Such intersections regulate the inward (central) deformation of the stent.

The two linear components 41 and 42 of the V-shaped connecting portion 4 include deformed portions 41a and 42a. The deformed portions 41a and 42a are provided on one end side, in other words, on the other end side bending portion 30. The deformed portions 41a and 42a bend the linear components 41 and 42 toward the other end side 43 side of the V-shaped connecting portion 4. Therefore, the linear components 41 and 42 on one end side of the deformed portions 41a and 42a face the other end side 43 of the V-shaped connecting portion 4 slightly diagonally from the other end side bent portion 30. The linear components 41 and 42 on the other end side of the deformed portions 41a and 42a are larger than the one end side portion and face the other end side 43 of the V-shaped connecting portion 4.

Further, from a different point of view, the stent 1 is formed by a plurality of V-shaped connecting portions 4 and the other end side bent portion 30 connected to the V-shaped connecting portion 4, and is formed with respect to the central axis of the stent 1. A plurality of first inclined linear portions 51 inclined in one direction and a second direction different from the inclined direction of the first inclined linear portion 51 with respect to the central axis of the stent 1 (specifically, the stent 1 A plurality of second inclined linear portions 52 inclined in a direction substantially symmetrical with respect to the central axis), and an intersection (V-shaped connecting portion 4) between the first inclined linear portion and the second inclined linear portion. It also has a linear network structure formed by a connecting portion between the other end side end portion 43 and the apex 22a of the one end side short bending portion 22).

Further, in the stent 1, one end side bent portion 21 (one end side long bent portion 21) is located in each mesh of the linear network structure, and one end side bent portion 21 (one end side long bent portion 21) 2 The other end side end portion is connected to the vicinity of the central portions 51a and 52a of the two other end side linear components forming each mesh, and each mesh is formed into a substantially square hollow shape by the one end side bending portion 21. It is divided into a portion 5a and a substantially “K” -shaped hollow portion 5b.

For this reason, in the entire stent, the hollow portion is a plurality of substantially “dogleg” -shaped hollow portions in which the above-mentioned relatively small closed shape substantially square hollow portion 5a is relatively wide and has an open shape. It is surrounded by the part 5b. Such a form contributes to good compressibility and expansion retention of the stent 1.

The plurality of bent portions 30 on the other end side of the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f are substantially located on one circumference orthogonal to the central axis of the stent 1. preferable.
Further, the total number of the bent portions 20, 21 and 22 on the one end side and the bent portions 30 on the other end side in the annular bodies 2a, 2b, 2c, 2d, 2e, and 2f is preferably 8 to 40, and in particular, 16 It is preferably ~ 24. Further, the number of V-shaped connecting portions 4 between the adjacent annular bodies 2a, 2b, 2c, 2d, 2e, and 2f is 1/2 of the number of the bent portions on one end side. The number of bent portions 30 on the other end side, which are free ends, is preferably 2 to 10, and particularly preferably 4 to 8.

Further, the stent 1 has a portion other than the annular body 2a located at one end of the stent 1 and the annular body 2f located at the other end, and the number of linear components existing in the cross section orthogonal to the central axis of the stent 1 is determined. It is preferable that they are almost the same. In this way, almost the entire stent has a substantially uniform expansion holding force. The number of linear components existing in the cross section orthogonal to the central axis of the stent 1 is preferably 8 to 40, and particularly preferably 16 to 24.

Further, in the stent 1 of this embodiment, the distance between adjacent annular bodies is substantially zero or close to zero. Specifically, in the adjacent annular bodies 2a, 2b, 2c, 2d, 2e, 2f, the other end edge of the apex of the other end side bending portion 30 of the annular body on one end side and the annular body on the other end side adjacent to each other. The tip edge of the apex of the bent portion 21 on one end side of the stent 1 is substantially the same position in the axial direction of the stent 1. Therefore, when the stent 1 is compressed, the vertices of both bent portions do not overlap, and a portion where the linear component constituting the bent portion does not exist is not formed.

A superelastic metal is suitable as a constituent material of the stent. As the superelastic metal, a superelastic alloy is preferably used. The superelastic alloy referred to here is generally called a shape memory alloy, and exhibits superelasticity at least at a biological temperature (around 37 ° C.). Particularly preferably, a Ti—Ni alloy of 49 to 53 atomic% Ni, a Cu—Zn alloy of 38.5 to 41.5 wt% Zn, and a Cu—Zn—X alloy of 1 to 10 wt% X (X = Be, Superelastic alloys such as Si, Sn, Al, Ga) and 36-38 atomic% Al Ni—Al alloys are preferably used. Particularly preferred is the Ti—Ni alloy described above. Further, a Ti—Ni—X alloy in which a part of the Ti—Ni alloy is replaced with 0.01 to 10.0% X (X = Co, Fe, Mn, Cr, V, Al, Nb, W, B, etc.) Or a Ti—Ni—X alloy (Y = Cu, Pb, Zr) in which a part of the Ti—Ni alloy is replaced with 0.01-30.0% Y, and the cold working rate. Alternatively, the mechanical properties can be changed as appropriate by selecting / and the conditions of the final heat treatment. Further, the mechanical properties can be appropriately changed by selecting the cold working rate and / or the conditions of the final heat treatment using the above Ti—Ni—X alloy. The buckling strength (yield stress under load) of the superelastic alloy used is 5 to 200 kg / mm ² (22 ° C), more preferably 8 to 150 kg / mm ² , and the restoring stress (yield stress during unloading). ) Is 3 to 180 kg / mm ² (22 ° C.), more preferably 5 to 130 kg / mm ² . The term "superelasticity" as used herein means that even if a metal is deformed (bent, pulled, compressed) to a region where it is plastically deformed at the operating temperature, it recovers to almost the shape before compression without requiring heating after the deformation is released. Means to do.

When the stent 1 is used for dilation of a cerebral blood vessel, for example, the diameter at the time of dilation (uncompressed) is preferably about 0.8 to 1.8 mm, and particularly 0.9 to 1.8 to 1. 1.4 mm is more preferable. The length of the stent when expanded (uncompressed) is preferably about 5 to 50 mm.

Further, in the stent 1, each annular body 2a, 2b, 2c, 2d, 2e except the other end is provided with an even number of other end side bending portions 30 (and an even number of one end side bending portions 20, 21, 22). Is preferable, and the number of V-shaped connecting portions 4 is halved. The number of bent portions on one end side and the other end side of one annular body 2a, 2b, 2c, 2d, 2e, 2f is preferably 4 to 15, and particularly preferably 4 to 10. The length of each annular body 2a, 2b, 2c, 2d, 2e, 2f is preferably about 0.7 to 2.0 mm. Further, the number of annular bodies 2a, 2b, 2c, 2d, 2e, and 2f in the stent 1 is preferably 4 to 10. Further, the wall thickness of the stent is preferably about 0.05 to 0.15 mm, and particularly preferably 0.08 to 0.13 mm. The width of the linear component constituting the stent is preferably about 0.04 to 0.15 mm, and particularly preferably 0.05 to 0.13 mm.

Further, the stent 1 of this example includes a contrast marker 7. The contrast marker 7 is preferably provided on the end side of the stent. In particular, it is preferable to provide them on both ends. As shown in FIG. 1, it is preferable to provide a plurality of markers 7 on both ends.
The stent 1 of this embodiment has an annular portion 6 having an opening at the center protruding from the apex of the one-end side bent portion 20 located at one end of the stent, and the marker 7 is fixed so as to occlude the annular portion 6. ing.

For such a marker, for example, a disk-shaped member of an X-ray contrast medium having a portion slightly smaller and a portion larger than the small opening is placed in a small opening formed in the stent and pressed from both sides to form a rivet. , It is preferable to attach it by caulking.

The marker for contrast may be any marker for X-ray contrast, ultrasonic contrast, and the like. The marker is formed of a contrast-enhancing substance such as an X-ray contrast-enhancing substance or an ultrasonic contrast-enhancing substance. As the marker forming material, for example, gold, platinum, tungsten, tantalum, iridium, palladium or an alloy thereof, or a gold-palladium alloy, platinum-iridium, NiTiPd, NiTiAu or the like is suitable.

Next, the stent delivery system of the examples of the present invention will be described with reference to the examples shown in the drawings.
FIG. 5 is a partially omitted front view of the stent delivery system according to the embodiment of the present invention. FIG. 6 is an enlarged vertical cross-sectional view of the vicinity of the tip of the stent delivery system shown in FIG.
The stent delivery system 10 of this embodiment is for slidably inserting the sheath 12, the stent 1 housed in the tip of the sheath 12, and the inside of the sheath 12, and releasing the stent 1 from the tip of the sheath 12. It includes an inner tube 14.
In the stent delivery system 10 of this embodiment, the stent 1 is formed in a cylindrical shape, is compressed in the central axial direction when inserted in a living body, and can be expanded outward and restored to the shape before compression when placed in a living body. The self-expanding stent described above is used.

As shown in FIG. 5, the stent delivery system 10 of this embodiment includes a sheath 12, a self-expandable stent 1, and an inner tube 14.
As shown in FIGS. 5 and 6, the sheath 12 is a tubular body, and the tip and base ends are open. The tip opening functions as an outlet for the stent 1 when the stent 1 is placed in a narrowed portion in the body cavity. By sliding the sheath 12 toward the proximal end side, the stent 1 is released from the tip opening, the stress load is released, and the stent 1 expands and restores the shape before compression. The tip of the sheath 12 is a stent accommodating portion 15 for accommodating the stent 1 inside. Further, the sheath 12 is provided with a side hole 41 provided on the base end side of the storage portion 15. The side hole 41 is for leading the guide wire to the outside.

The outer diameter of the sheath 12 is preferably about 1.0 to 4.0 mm, and particularly preferably 1.5 to 3.0 mm. The inner diameter of the sheath 12 is preferably about 0.8 to 2.5 mm. The length of the sheath 12 is preferably 300 to 2500 mm, particularly preferably about 300 to 2000 mm.
Further, as shown in FIG. 5, a sheath hub 16 is fixed to the base end portion of the sheath 12. The sheath hub 16 includes a sheath hub main body and a valve body (not shown) that is housed in the sheath hub main body and holds the inner pipe 14 in a slidable and liquid-tight manner. Further, the sheath hub 16 includes a side port 18 that branches obliquely rearward from the vicinity of the center of the sheath hub body. Further, it is preferable that the sheath hub 16 is provided with an inner pipe locking mechanism that regulates the movement of the inner pipe 14.

As shown in FIGS. 5 and 6, the inner pipe 14 is provided at the shaft-shaped inner pipe main body 40 and the tip of the inner pipe main body 40, and the tip 47 protruding from the tip of the sheath 12 and the inner pipe. An inner tube hub 17 fixed to a base end portion of the main body portion 40 is provided.
The tip portion 47 is preferably formed in a tapered shape that protrudes from the tip of the sheath 12 and gradually reduces in diameter toward the tip, as shown in FIG. By forming in this way, insertion into the narrowed portion becomes easy. Further, it is preferable that the inner tube 14 is provided on the distal end side of the stent 1 and is provided with a stopper that prevents the sheath from moving toward the distal end. The base end of the tip portion 47 is capable of contacting the tip end of the sheath 12, and functions as the stopper.

Further, as shown in FIG. 6, the inner tube 14 includes two protrusions 43 and 45 for holding the self-expandable stent 1. The protrusions 43 and 45 are preferably annular protrusions. A stent-holding protrusion 43 is provided on the proximal end side of the distal end portion 47 of the inner tube 14. A stent extrusion protrusion 45 is provided on the proximal end side of the stent holding protrusion 43 at a predetermined distance. The stent 1 is placed between these two protrusions 43 and 45. The outer diameters of the protruding portions 43 and 45 are large enough to come into contact with the compressed stent 1 described later.

Therefore, the movement of the stent 1 to the distal end side is restricted by the protruding portion 43, and the movement of the stent 1 to the proximal end side is restricted by the protruding portion 45. Further, when the inner tube 14 moves to the distal end side, the stent 1 is pushed toward the distal end side by the protruding portion 45 and is discharged from the sheath 12. Further, as shown in FIG. 6, the proximal end side of the stent extrusion protrusion 45 is preferably a tapered portion 46 whose diameter gradually decreases toward the proximal end side. Similarly, as shown in FIG. 6, the proximal end side of the stent-holding protrusion 43 is preferably a tapered portion 44 whose diameter gradually decreases toward the proximal end side.

By doing so, when the inner tube 14 is projected from the tip of the sheath 12, the stent 1 is released from the sheath, and then the inner tube 14 is re-stored in the sheath 12, the protruding portion is caught by the tip of the sheath. To prevent that. As described above, the stent 1 of the present invention does not have a bent portion 30 on the other end side which is a free end, except for the annular body 2f located at the other end of the stent 1, and the stent is provided. Even if it is exposed to some extent, it can be re-stored in the sheath 12. Further, the protruding portions 43 and 45 may be formed of a separate member from an X-ray contrast-enhancing material. As a result, the position of the stent can be accurately grasped under X-ray contrast, and the procedure becomes easier.

As shown in FIG. 6, the inner tube 14 has a lumen 48 extending from the tip to at least the stent storage site 15 of the sheath 12 to the proximal end side, and an inner tube side hole 42 communicating with the lumen 48 at the proximal end side from the stent storage site. And have. In the stent delivery system 10 of this embodiment, the lumen 48 is terminated at the site where the side hole 42 is formed. The lumen 48 is for inserting one end of a guide wire from the tip of the stent delivery system 10, partially inserting the inside of the inner tube, and then guiding the lumen 48 to the outside from the side surface of the inner tube. The inner tube side hole 42 is located slightly closer to the distal end side of the stent delivery system 10 than the sheath side hole 41. The center of the inner tube side hole 42 is preferably 0.5 to 10 mm from the center of the sheath side hole 41.

The stent delivery system is not limited to the above-mentioned type, and the above-mentioned lumen 48 may extend to the base end of the inner tube. In this case, the side hole 41 of the sheath becomes unnecessary.
Then, the inner tube 14 penetrates the inside of the sheath 12 and protrudes from the base end opening of the sheath 12. As shown in FIG. 5, the inner pipe hub 17 is fixed to the base end portion of the inner pipe 14.

1 In-vivo indwelling stent 2a, 2b, 2c, 2d, 2e, 2f Annulus 20 One-sided bending part 21 One-sided long bending part 22 One-sided short bending part 30 One-sided bending part 4 V-shaped connecting part 10 Stent Delivery system

Claims (15)

Formed by a wavy and annular linear component having a plurality of one-sided bends having vertices on one end in the axial direction and a plurality of other-side bends having vertices on the other end in the axial direction of the stent. It is a tubular in-vivo indwelling stent in which the formed annulus is arranged in a plurality of axial directions and the adjacent annular bodies are connected to each other.
In the annular body other than the annular body located at the other end of the stent, the apex of all two adjacent other end side bending portions of each annular body is one one end of the adjacent annular body. The side bend and the V-shaped connecting portion are connected, and the adjacent annular bodies are connected by a plurality of the V-shaped connecting portions, and the stent is further attached to the other end of the stent. Except for the located annular body, the annular body does not have the other end side bent portion having a free end at the apex, and each of the annular bodies includes a plurality of the one end side bent portions having a free end at the apex. In vivo indwelling stent. The in-vivo indwelling stent according to claim 1, wherein the bent portion on one end side of the stent is arranged so as to be substantially linear in the axial direction of the stent. The in-vivo indwelling stent according to claim 1 or 2, wherein the bent portion on the other end side of the stent is arranged so as to be substantially linear in the axial direction of the stent. The in-vivo indwelling stent according to any one of claims 1 to 3, wherein the stent is formed with an intersection formed by the V-shaped connecting portion and the one-sided bending portion connected to the V-shaped connecting portion. The in vivo according to any one of claims 1 to 4, wherein the annular body excluding the annular body located at the other end of the stent includes the same number of the one end side bending portions and the same number of the other end side bending portions. Indwelling stent. The annular body excluding the annular body located at one end of the stent alternates between a long bending portion on one end side having a long bending portion and a short bending portion on one end side having a shorter bending portion than the long bending portion on one end side. The in vivo indwelling stent according to any one of claims 1 to 5. The in-vivo indwelling stent according to claim 6, wherein the one-sided long bending portion and the one-one-side short bending portion of the stent are arranged substantially linearly and alternately in the axial direction of the stent. The two end side ends of the V-shaped connecting portion are connected to the vertices of the two bent portions on the other end side, and the other end side of the V-shaped connecting portion is the short bent portion on the one end side. The in vivo indwelling stent according to claim 6 or 7, which is connected to the apex. The stent is formed by a plurality of the V-shaped connecting portions and the other end side bent portions connected thereto, and includes a plurality of first inclined linear portions inclined in a first direction with respect to the central axis of the stent. A plurality of second inclined linear portions inclined in a second direction different from the inclined direction of the first inclined linear portion with respect to the central axis of the stent, and the first inclined linear portion and the second inclined portion. The in vivo indwelling stent according to any one of claims 1 to 8, which has a linear network structure formed by an intersection with a linear portion. In the stent, the one end side bending portion is located in each mesh of the linear mesh structure, and the two other end side ends of the one end side bending portion are the two others forming the respective meshes. Claims that are connected to the vicinity of the central portion of the end-side linear component, and each of the meshes is divided into a substantially square hollow portion and a substantially "<" -shaped hollow portion by the one-end side bent portion. Item 9. In vivo indwelling stent. The in-vivo placement according to any one of claims 1 to 10, wherein the plurality of bent portions on the other end side of the annular body are substantially located on one circumference orthogonal to the central axis of the stent. Stent for. The in-vivo indwelling stent according to any one of claims 1 to 11, wherein the number of bent portions on one end side in the annular body excluding the annular body located at the other end of the stent is an even number. In the stent, the number of linear components existing in a cross section orthogonal to the central axis of the stent is approximately the same except for the annular body located at one end of the stent and the annular body located at the other end. The in vivo indwelling stent according to any one of claims 1 to 12, which is the same. Any of claims 1 to 13, wherein the stent is formed in a substantially cylindrical shape, is compressed in the central axial direction when inserted in a living body, and expands outward when placed in a living body to restore the shape before compression. In vivo indwelling stent according to. It is characterized by including a sheath, a stent according to claim 14 housed in the tip of the sheath, and an inner tube for slidably inserting the inside of the sheath and pushing the stent out of the tip of the sheath. Stent delivery system.

Images