JP2003088591A - Stent and graft with stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent easily contractible in diameter, having sufficient extending force, minimized in length change between diameter contracting time and diameter extending time, and hardly buckling-deformed, and a graft with stent. SOLUTION: This graft 10 with stent comprises the stent 20 formed by cylindrical weaving a metal wire rod in a mesh form and a cylindrical cover 30 for covering the circumference of the stent 20. The stent 20 comprises an intersection part A where metal wire rods 21 pass crosswise and an intersection part B where the wire rods are mutually combined at a V-shaped folding part. The combined intersection part B is annularly arranged along the circumferential direction of the stent 20. The area where the combined intersection part B is annularly arranged is provided in at least one position along the axial direction of the stent 20. The combined intersection part B is preferably annular arranged along the circumferential direction while being alternately shifted in the axial direction of the stent 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stent and a graft with a stent which are inserted and placed in a tubular organ of a human body such as a blood vessel, a ureter, a bile duct, a trachea.

[0002]

2. Description of the Related Art In recent years, a stent has been inserted and placed through a catheter for treatment of tubular organs of the human body such as blood vessels, ureters, bile ducts, and trachea. For example, a treatment method is known in which a stent is placed in a narrowed portion of a blood vessel to expand it, or a stent is placed in a place where an aneurysm is formed to prevent the aneurysm from rupturing. In particular, in the treatment of aneurysms, a stent-equipped graft obtained by covering the outer circumference of the stent with a woven fabric called a graft is used.

As a conventional stent, for example, Japanese Unexamined Patent Publication No. Hei 11
In Japanese Patent Laid-Open No. 57021, a predetermined number of filaments are twisted in a sinusoidal shape to form a cylindrical basket-shaped braid structure, and both ends of the cylindrical cage-shaped braid structure are folded or joined to each other. Disclosed is a stent characterized in that it is formed into a loop structure and each filament is an infinite loop with no ends as a whole.

Further, Japanese Patent No. 2975584 discloses that
In a stent for expanding a body cavity, which is composed of one filament formed from a cylindrical shape having a number of zigzag bands, the band includes a number of straight portions, peak portions and valley portions, and the peak portions and valley portions. Are arranged in the circumferential direction of the stent and on the same plane, and the peak portion of the adjacent lower band is connected to the valley portion forming the band by a twist method of twisting at least one and a half rotations or more. A stent for expanding a body cavity is disclosed, wherein the filament of the adjacent lower band is a filament extending downward from the end straight portion of the adjacent upper band.

Further, Japanese Patent Laid-Open No. 2000-279529 discloses a self-expanding device which is formed into a substantially cylindrical shape and has an outer diameter that is compressed when inserted in a living body and expands when placed in a living body to restore its original shape. A stent for indwelling in a mold body cavity, an inner sheath that holds the inner diameter of the stent on the inner surface of the distal end in a compressed state, an outer sheath that houses the inner sheath, and a discharge mechanism that discharges the stent in a living body An apparatus for treating a lesion in a body cavity, comprising: a stent, a side surface of which is coated with a film; and the outer sheath is capable of discharging the distal end portion of the inner sheath from the distal end, and at least slightly from the distal end. Disclosed is a device for treating a lesion in a body cavity, which is provided with a blood circulation opening at a position on the proximal side.

[0006]

SUMMARY OF THE INVENTION These stents are
While being attached to the inner periphery of the distal end of the catheter, the catheter is carried to a predetermined position in the tubular organ of the human body and is pushed out of the catheter there to be left in the tubular organ. Therefore, the diameter of the catheter can be easily reduced when it is attached to the inner circumference of the distal end of the catheter, and when it is pushed out from the catheter, the tubular organ can be spread with a sufficient expansion force. There is a demand for a structure in which there is little change in length between when the diameter is expanded and when the material is extruded and the position is unlikely to shift. Further, it is also required that it is less likely to buckle and deform when it is inserted into a curved conduit such as a blood vessel.

Therefore, an object of the present invention is to provide a stent and a stent which can be easily reduced in diameter, have a sufficient expansion force, have little change in length between the diameter reduction and the diameter expansion, and are less likely to buckle and deform. To provide an attached graft.

[0008]

In order to achieve the above object, a first aspect of the present invention is a stent formed by knitting a metal wire rod to form a tubular shape, wherein the metal wire rod is V-shaped. Has a portion that is assembled and intersects with each other in a shape-folded portion, and a portion that the metal wire rod intersects in a cross shape, and the portion that is assembled and intersects has an annular shape along the circumferential direction of the stent. The present invention provides a stent, which is arranged, and the annular arrangement of the assembled and intersecting portions is at least at one position along the axial direction of the stent.

According to the above invention, in the portion where the metal wire rods cross each other in a cross shape, the metal wire rods can be slid or the crossing angle can be changed relatively freely. On the other hand, at the portions where the metal wire rods are folded back in a V shape and are assembled with each other and intersect with each other, the metal wire rods are less likely to slide and the crossing angle is less likely to change. As a result, the diameter of the crossed portion is likely to be reduced, but the expansion force tends not to be so large. The diameter of the assembled and intersected portion is difficult to reduce, but the expansion force tends to be strong. Further, since the metal wire rods are assembled and intersect at the intersecting portion, the elongation of the axial length at the time of the diameter reduction is suppressed, and the change in the length between the diameter reduction and the diameter expansion becomes small. .

Therefore, according to the above invention, the diameter can be relatively easily reduced when the catheter is inserted into the inner circumference of the catheter, and a sufficient expansion force can be obtained when the catheter is extruded from the catheter. Thus, it is possible to provide a stent whose length changes little and which is less likely to buckle and deform.

In a second aspect of the present invention, in the first aspect of the invention, the assembled and intersecting portions are circumferentially displaced while being displaced in the axial direction of the stent, preferably alternately alternating in the axial direction of the stent. The present invention provides a stent that is arranged in a ring shape along the stent.

According to the above invention, since the assembled and intersecting portions are arranged along the circumferential direction while being displaced in the axial direction, the expansion force is applied evenly with a relatively wide width, and locally. It is possible to prevent the occurrence of a portion that is difficult to reduce the diameter so as not to impair the workability when reducing the diameter.

Further, since the portion having a high expansion force is formed in a ring shape along the circumferential direction with a relatively wide width, the stent buckles and deforms even when it is inserted into a bent portion of a tubular organ such as a blood vessel. (Bent so that the flow path is crushed)
It becomes difficult to do it, and safety can be improved.

In a third aspect of the present invention, in the first or second aspect of the invention, the assembled and intersecting portions are made of a metal wire rod that is folded back into a V shape at a small angle, and a V shape at a larger angle.
The present invention provides a stent in which metal wires that are folded back in a letter shape are combined with each other.

According to the above invention, since the metal wire rod which is folded back into a V shape at a small angle extends in the axial direction relatively long and is intertwined with the metal wire rod which is bent back into a V shape at a large angle, the shafts of the intersecting parts are assembled. It is possible to widen the deviation width in the direction and average the expansion force in the portions arranged along the circumferential direction while the assembled and intersecting portions are displaced in the axial direction alternately.

In a fourth aspect of the present invention, in any one of the first to third aspects, the annular array of the assembled and intersecting portions sandwiches the annular array of the cross-shaped intersecting portions, The present invention provides a stent provided at at least two positions along the axial direction of the stent.

According to the above invention, since the annular arrangement of the intersecting and assembled portions is provided at at least two positions along the axial direction of the stent with the annular arrangement of the intersecting portions in the cross shape interposed therebetween. Applying expansion force and buckling deformation prevention force,
It can be applied evenly over the entire axial direction of the stent.

A fifth aspect of the present invention provides a stent-equipped graft comprising the stent of the first to fourth aspects of the present invention and a tubular cover that covers a part or all of the inner circumference and / or the outer circumference of the stent. It is a thing.

According to the above invention, it is possible to prevent blood from flowing into the aneurysm by arranging the blood vessel at the place where the aneurysm is formed.

In the present invention, it is preferable that the assembled and intersecting portions are formed by entwining the metal wire rods without making a round.

According to the above-mentioned invention, since the metal wire rods are entwined with each other without making one round, the intersecting and assembled portions are entangled when the metal wire rods are twisted at least one and a half rotations or more. Compared with, the degree of freedom when the diameter is reduced is increased.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to only these embodiments.

One embodiment of a stented graft according to the present invention is shown in FIGS. 1 is a perspective view showing a tubular cover of the stent-equipped graft with a part thereof cut away, FIG. 2 is a perspective view showing the stent-equipped graft stent, FIG. 3 is a development view showing a knitting pattern of a metal wire rod, and FIG. FIG. 5 is a side view showing a reduced diameter state and an enlarged diameter state of the stent-equipped graft, and FIG. 5 is an explanatory view showing a state in which the stent-equipped graft is arranged inside an aneurysm of a blood vessel.

As shown in FIG. 1, the stent-equipped graft 10 includes a stent 20 formed by knitting a predetermined number of metal wires 21 in a mesh shape and a tubular shape, and the stent 2
And a cylindrical cover 30 that covers 0.

The stent 20, as shown in FIGS.
A portion A where the metal wire rod 21 intersects in a cross shape and a portion B where the metal wire rod is folded into a V shape and assembled and intersect with each other.
And have. And the part B that is assembled and intersects,
The stents 20 are arranged annularly along the circumferential direction while being alternately displaced in the axial direction of the stent 20.

The stent 20 has a region II in which the assembled and intersecting portions B are annularly arranged as described above, and a region I in which the cross-shaped intersecting portions A are annularly arranged, Regions II and I are alternately repeated in the axial direction, and in this embodiment, regions II are provided at a total of three places. As a result, an expansion force and a buckling deformation preventing force that are as uniform as possible in the axial direction can be obtained.

Further, the assembled and intersecting portion B is formed by intertwining a metal wire rod 21a which is folded back in a V shape at a small angle and a metal wire rod 21b which is bent back in a V shape at a larger angle. In the case of 2 and 3, when the assembled and intersecting portion B is arranged above, the above-mentioned wire rod 21b having a large angle V shape and the above wire rod 21a having a small angle V shape are provided below. When the portion B that is arranged and assembled and intersects is arranged below, the above-mentioned wire 21a having a small angle V-shape and the above-mentioned wire 21b having a large angle V-shape are arranged below. ing.

As a result, the metal wire rods 21a which are folded back in a V shape at a small angle are arranged so as to connect the intersecting portions B which are displaced in the axial direction, and the axial displacement is made large so that the expansion force is increased. The particles are dispersed so that the expansion force and the buckling degeneration preventing force of the stent 20 can be obtained in the axial direction as uniformly as possible.

Further, in this embodiment, the metal wire rods 21 are bent in a V-shape, and the bent portions are intertwined with each other without making a round. Here, “without making one round” means a state in which the metal wire rods 21 are engaged with each other only at the bent portions and are not wrapped around the wire rod of the other party. As a result, the degree of freedom when the diameter of the intersection B is reduced can be increased. However, the metal wire rod 21 is the other metal wire rod 21.
It can also be entwined by wrapping it around one and a half rounds.

It should be noted that all intersecting portions of the metal wire rod 21 (A +
The ratio of the assembled and intersecting portions B to B) is preferably 2 to 50%, more preferably 3 to 40%, more preferably 4 to 35%, and particularly preferably 5 to 30%. If the portion B that is assembled and intersects is less than 2%, the improvement effect of the expansion force and the effect of reducing the length change between the diameter reduction and the diameter expansion become poor.

Further, in the present invention, the weaving pattern of the metal wire rod 21 may be changed in density.

It is preferable that the intersections of the metal wire rods 21 are not fixed to each other, thereby increasing the degree of freedom of displacement between the wire rods 21 and reducing the diameter when inserting the catheter or expanding the diameter when extruding from the catheter. Can be made easier. The portions where the ends of the metal wire 21 overlap with each other and the portions where the ends of the metal wire 21 and the metal wire 21 overlap with each other may be fixed by, for example, solder, metal brazing, or an adhesive. Further, the stent 20 may be knitted with a single metal wire rod 21 or a plurality of metal wire rods 21.

As the material of the metal wire 21, a shape memory alloy which gives a shape memory effect by heat treatment and superelasticity is preferably adopted, but depending on the application, stainless steel, tantalum, titanium, platinum, gold, tungsten. Etc. may be used. As the shape memory alloy, Ni-Ti system,
Cu-Al-Ni type, Cu-Zn-Al type and the like are preferably used. Further, the surface of the shape memory alloy may be coated with gold, platinum, or the like by a means such as plating. The thickness of the metal wire 21 is not particularly limited, but in the case of, for example, a blood vessel stent, it is preferably 0.08 to 1 mm.

The cylindrical cover 30 is formed by molding a thermoplastic resin into a cylindrical shape by a molding method such as extrusion molding or blow molding, a knitted fabric of a thermoplastic resin fiber formed into a cylindrical shape, or a cylindrically formed heat. A non-woven fabric of a plastic resin, a sheet of a flexible resin formed in a cylindrical shape, a porous sheet, or the like can be used. As the knitted fabric, known knitted fabrics and fabrics such as plain weave and twill weave can be used. In addition, the tubular cover 30
As the, it is possible to use a crimped product or the like with a fold. Further, as the cylindrical cover 30, a cover provided with holes on its side can be used.

Among these, as the cylindrical cover 30, a knitted woven fabric of thermoplastic resin fibers formed in a cylindrical shape, and a plain woven fabric of thermoplastic resin fibers formed in a cylindrical shape are particularly preferable. It is preferable because it has excellent porosity and productivity.

As the thermoplastic resin, polyethylene, polypropylene, polyolefin such as ethylene-α-olefin copolymer, polyamide, polyurethane, polyethylene terephthalate, polybutylene terephthalate,
Polycyclohexane terephthalate, polyethylene-
Resins such as polyesters such as 2,6-naphthalate and fluororesins such as polyfluorinated ethylene and polyfluorinated propylene, which have less durability and less tissue reaction, can be used.

In particular, polyesters such as polyethylene terephthalate and fluororesins such as polyfluorinated ethylene and polyfluorinated propylene, which are chemically stable, have high durability, and have little tissue reaction, can be preferably used.

The tubular cover 30 can be fixed to a part or the whole of the stent 20 by using known fixing means such as sewing, adhesion, and welding. Especially the cylindrical cover 30
Are preferably fixed at or near the ends of the stent 20. In this case, it is necessary to select a fixed portion to the stent 20 so as not to prevent the diameter reduction and the diameter expansion of the stent 20. The tubular cover 30 may cover the inner circumference of the stent 20.

The tubular cover 30, the fibers constituting the cover, and the metal wire 21 constituting the stent 20 are those coated with an antithrombotic material such as heparin, collagen, acetylsalicylic acid, or gelatin. You can also

Further, an X-ray impermeable material may be fixed to an appropriate portion of the stent-equipped graft 10 such as both ends. As the X-ray opaque material, for example, gold, platinum, iridium, tantalum, tungsten, silver and the like, and alloys containing them are preferably used. The radiopaque material is soldered to the stent 20,
It can be fixed by means such as brazing, welding, adhesion, and caulking.

The stent-graft 10 of the present invention thus obtained preferably has an outer diameter of about 2 to 50 mm and a length of about 1 to 20 cm.

Next, a method of using the above-mentioned stent-equipped graft 10 will be described. This stent graft 3
0 is applicable to all parts of the human body tubular organs such as blood vessels, ureters, bile ducts, and bronchi, but it is especially placed inside the aneurysm of blood vessels to prevent blood from flowing into the aneurysm. Suitable for treatment to prevent rupture of aneurysm.

An example of the procedure for inserting a blood vessel to treat an aneurysm will be described below. First, a guide wire is inserted into a blood vessel by a conventional method, its tip is positioned in the affected area, and then a parent catheter is inserted along the outer circumference of the guide wire. When the tip reaches a target location, the guide wire is pulled out.

Then, the graft 10 with the stent is reduced in diameter as shown in FIG. 4 (A) and inserted into the distal end portion of the child catheter. At this time, the portion A of the graft with stent 10 that intersects with the cross of the stent 20 has a metal wire rod 21.
Since the positions are relatively freely displaced and the crossing angle thereof is relatively freely changeable, the diameter is easily reduced. Further, in the part B where the wires are assembled and intersected, the metal wire rods 21 are unlikely to slide, and the crossing angle is also difficult to change (a repulsive force is generated if the part bent in the V-shape is further reduced), and thus it is difficult to reduce the diameter. As described above, since the assembled and intersecting portions B are arranged along the circumferential direction while being alternately displaced in the axial direction as described above, a portion where it is difficult to reduce the diameter locally occurs. Therefore, the ease of diameter reduction can be maintained so that the catheter insertion work is prevented.

When the tip of the child catheter reaches the affected area in this way, a pusher is inserted into the child catheter, and the stent-equipped graft 10 is pushed inside the aneurysm a'of the blood vessel a as shown in FIG. Then, since the stent-equipped graft 10 is a self-expanding type, it expands in diameter as shown in FIG. 4B by its self-expanding force. As a result, both ends of the stent-equipped graft 10 are arranged in close contact with the inner circumferences of both ends of the aneurysm a '.

At this time, since the stent 20 constituting the stent-equipped graft 10 is formed by knitting the metal wire rod 21 in a mesh shape and a tubular shape, it naturally conforms to the bent shape of the blood vessel B, and Adhere tightly to the inner circumference of the blood vessel b. Further, in the stent 20, a region II in which assembled and intersecting portions B are arranged along the circumferential direction while being alternately displaced in the axial direction is sandwiched by a region I in which cross-shaped intersecting portions A are arranged. Since it is provided at a plurality of locations, the expansion force is strong as a whole, and the closeness of the blood vessel (i) to the inner wall is improved. As a result, the blood flowing in the blood vessel a does not flow into the aneurysm a ′ through the stent-equipped graft 10, so that the risk of rupture of the aneurysm a ′ can be avoided.

Further, the stent 20 has regions II in which the assembled and intersecting portions B are annularly arranged along the circumferential direction while being alternately displaced in the axial direction at a plurality of positions at predetermined intervals in the axial direction. , The expanded state of the mesh is regulated at that portion, so that the diameter is reduced in FIG. 4 (A)
In the expanded state (B), there is an advantage that the change in axial length is reduced. For this reason, when pushed out from the child catheter, it is unlikely to be displaced and workability is improved.

Further, since the region II in which the assembled and intersecting portions are arranged exhibits a strong resistance to the force of crushing the tubular shape, the seat II when it is inserted into a bent place such as a blood vessel. Flexural deformation can be prevented.

FIG. 6 is a development view of a knitting pattern showing another embodiment of the stent used in the graft with a stent of the present invention.

This stent 20b basically has the same knitting pattern as the stent 20 shown in FIG. That is, a region I in which a portion A intersecting in a cross shape is formed in a ring shape along the circumferential direction with a predetermined width, and a portion B in which the assembled and intersecting portions are displaced in the axial direction alternately form a ring shape in the circumferential direction. The formed regions II are formed alternately in the axial direction.

However, in this stent 20b, in the region I disposed at both ends in the axial direction, the metal wire rod 21 positioned closest to the end has a portion 21c protruding in a V-shape in the axial direction. It's different. That is, the V-shaped projecting portions 21c are formed so as to further project in the axial direction from both ends of the stent 20b, and a plurality of the projecting portions 21c are arranged at predetermined intervals in the circumferential direction.

According to this stent 20b, the V-shaped projecting portion 21c can be bent, for example, toward the outer diameter side to have a shape in which both ends are expanded. Thereby, when placed in a tubular organ such as a blood vessel, the both ends of the stent-equipped graft are strongly pressed by the inner wall of the tubular organ, so that the close contact force and the fixing force with the inner wall of the tubular organ such as a blood vessel can be increased. .

[0053]

Example 1 A stent 20 having an outer diameter of 30 mmφ and a length of 90 mm when expanded was produced by knitting a shape memory alloy wire having a wire diameter of 300 μm into a cylindrical shape in a pattern as shown in FIG. .

The outer circumference of the stent 20 is covered with a tubular cover 30 made of polyester woven cloth,
At both ends, the tubular cover 30 was sewn and fixed to the stent 20. Thus, the graft 10 with a stent of the present invention was obtained.

The expansion force of the stent-equipped graft 10 was measured as a reaction force when the outer diameter was 10 mmφ.
The expansion force was 450 gf.

Further, when the diameter of the stent-equipped graft 10 covering the tubular cover (outer periphery) 30 having an inner diameter of 22 mmφ was reduced to 7 mm, the axial length of the stent-equipped graft 10 was 110 mm. Became.
That is, it is understood that the axial length increases by 13% when the diameter is reduced.

[0057]

As described above, according to the present invention,
When inserted into the inner circumference of the catheter, it is relatively easy to reduce the diameter, and when it is pushed out from the catheter, a sufficient expansion force is obtained. Moreover, the length change between the diameter reduction and the diameter expansion is small, and further buckling It is possible to provide a stent and a stent-equipped graft that do not easily deform.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a stent-equipped graft according to the present invention with a tubular cover partially cut away.

FIG. 2 is a perspective view showing a stent of the graft with the stent.

FIG. 3 is a development view showing a knitting pattern of a metal wire rod of the stent.

FIG. 4 is a side view showing a reduced diameter state and an enlarged diameter state of the stent-equipped graft.

FIG. 5 is an explanatory view showing a state in which the stent-equipped graft is arranged inside an aneurysm of a blood vessel.

FIG. 6 is a development view of a knitting pattern showing another embodiment of the stent used in the graft with a stent of the present invention.

[Explanation of symbols]

10 Stented graft 20, 20b stent 21 Metal wire rod 30 tubular cover A crossing part B Part that is assembled and intersects I Area where intersections are formed in a cross shape II Area where assembled and intersecting parts are formed B blood vessels Lee ’aneurysm

Continued front page    (72) Inventor Hiroshi Takahashi             51 Iwai-cho, Hodogaya-ku, Yokohama-shi, Kanagawa             Piolax Medical Device Co., Ltd.             Within (72) Inventor Hiroyuki Asano             51 Iwai-cho, Hodogaya-ku, Yokohama-shi, Kanagawa             Piolax Medical Device Co., Ltd.             Within (72) Inventor Kunio Kuwahara             No. 8 Ube Ko, No. 8 Goi Minami Coast, Ichihara City, Chiba Prefecture             Sanken Co., Ltd. (72) Inventor Hideki Furuya             No. 8 Ube Ko, No. 8 Goi Minami Coast, Ichihara City, Chiba Prefecture             Sanken Co., Ltd. F-term (reference) 4C167 AA44 AA50 AA53 AA54 CC08                       CC21 CC22 CC26

Claims (5)

[Claims] 1. A stent, which is formed by knitting a metal wire rod into a tubular shape, wherein the stent has a portion in which the metal wire rod is folded back in a V shape, and a portion where the metal wire rod is assembled and intersects with each other. And a cross-shaped intersecting portion, the assembled and intersecting portions are arranged annularly along the circumferential direction of the stent, and the annular arrangement of the assembled and intersecting portions is A stent characterized in being at least at one location along the axial direction of the stent. 2. The stent according to claim 1, wherein the assembled and intersecting portions are arranged annularly along the circumferential direction while being displaced in the axial direction of the stent. 3. The metal wire rod that is folded back into a V shape at a small angle and the metal wire rod that is bent back into a V shape at a larger angle are combined at the assembled and intersecting portions. The stent according to any one of 1 to 2. 4. The annular array of the assembled and intersecting portions sandwiches the annular array of the cross-shaped intersecting portions,
The stent according to any one of claims 1 to 3, wherein the stent is provided at at least two locations in the axial direction of the stent. 5. A graft with a stent, comprising: the stent according to any one of claims 1 to 4; and a tubular cover that covers a part or all of the inner circumference and / or the outer circumference of the stent.