JP2003079743A - Stent and graft with stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent and a graft with a stent in which a diameter is easily reduced, further, sufficient expandability is provided and the change of a length in the case of diameter reduction and diameter expansion is reduced. SOLUTION: A graft 10 with stent is composed of a stent 20 formed by weaving metal wires in the shape of cylinder and mesh and a cylindrical cover 30 overlaying the inner and/or outer periphery of this stent 20. The stent 20 has a portion A in which metal wires 21 cross, and a portion B in which the metal wires cross while being mutually woven at V-shaped turning parts. Then, it is preferable that a line L arrayed with the woven crossing portions B is extended spirally while being wound once or more times along with the outer periphery 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.

Therefore, an object of the present invention is to provide a stent and a stent-equipped graft which can be easily reduced in diameter, have a sufficient expansion force, and have a small change in length between the diameter reduction and the diameter expansion. is there.

[0008]

In order to achieve the above object, the stent 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. The present invention provides a stent characterized in that it has a portion that is folded back to be assembled with each other and intersects with each other, and a portion where the metal wire material intersects with each other in a cross shape.

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. Therefore, by combining these,
It is possible to provide a stent which has excellent expandability, is easy to be reduced in diameter, and has little change in length between the reduced diameter and the enlarged diameter, which is extremely easy to use.

In the stent of the present invention, it is preferable that the metal wire rods are folded back in a V shape, and the intersecting portions are arranged in a spiral shape. Also,
The portions where the metal wire rods are assembled and intersect with each other may be arranged in a plurality of spirals, or may be arranged in a spiral of a plurality of windings of 0.1 or more, and a plurality of them may be arranged in parallel. It may be arranged in a spiral shape, or may be arranged in parallel in a spiral shape with a plurality of windings of 0.1 or more.

The number of windings in the case where the portions where the wires are assembled and intersect with each other are arranged in a spiral shape is preferably 0.1 or more, more preferably 0.1 to 5, and more preferably 0.1 to 5. Is in the range of 0.1 to 3, particularly preferably 0.2.
The range of -2.5 is preferable. Further, the portions where the wire rods are assembled and intersect with each other may have a plurality of spiral shapes, and may be arranged so that the spiral shapes intersect with each other.

Since the portions where the metal wires are assembled and intersect with each other are arranged in a spiral shape as described above, the assembled and intersecting portions are arranged in a dispersed manner.
The uniformity of the expansion force in the circumferential direction of the stent is excellent, the uniformity of rigidity in the circumferential direction and the length direction of the stent is improved, and the length change between the diameter reduction and the expansion is reduced.

In the stent according to the present invention, one or a plurality of the cross-shaped intersecting portions are arranged between the assembled and intersecting portions, and the assembled and intersecting portions are arranged in a spiral pattern. May be arranged in.

According to the above-mentioned invention, since the assembled and intersecting portions are arranged in a dispersed manner, the expansion force in the circumferential direction of the stent is excellent, and the rigidity of the stent in the circumferential direction and the longitudinal direction is uniform. Is improved, and the change in length between when the diameter is reduced and when it is expanded is reduced.

In the stent of the present invention, the assembled and intersecting portions are spirally arranged, and the arrangement line is
At least one may be arranged on any line along the axial direction and on any line along the circumferential direction.

[0016] According to the above invention, since the intersecting and assembled parts are arranged in a dispersed manner, the expansion force in the circumferential direction of the stent is excellent, and the rigidity of the stent in the circumferential direction and the longitudinal direction is uniform. Is improved, and the change in length between when the diameter is reduced and when it is expanded is reduced.

The present invention can also provide a stent-equipped graft having a tubular cover covering the inner circumference and / or the outer circumference of the stent.

The tubular cover can be fixed to a part or the whole of the stent of the present invention by using known fixing means such as sewing, adhesion, and welding. In particular, it is preferable to fix the tubular cover at or near the end of the stent of the present invention.

The tubular cover can cover a part or all of the outer circumference and / or the inner circumference of the stent of the present invention.

[0020]

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,
They are arranged in a spiral shape of 0.1 or more windings along the outer periphery of the stent 20, and in this embodiment, three spiral lines L are formed in parallel in the development view of FIG.

The portion B which is assembled and intersects is a metal wire rod 21.
They are bent in a V shape and are entwined with each other at their bent portions 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.

Further, in the stent 20 shown in FIG. 3, the line L in which the assembled and intersecting portions B are arranged is on any line along the axial direction of the stent 20 (direction of arrow C in FIG. 3) and in the circumferential direction. There is at least one on each arbitrary line along (the direction of arrow D in FIG. 3) (the line L is intersected at least once on the arbitrary line). As a result, the rigidity improving effect due to the assembled and intersecting portions B can be imparted over the entire stent 20.

Note that all the crossing portions of the metal wire rod 21 (A +
The proportion of the assembled and intersecting portion B with respect to B) is preferably 2 to 50%, more preferably 3 to 40%, more preferably 4 to 35%, particularly preferably 5 to 30%. It is preferable because the force is improved, the uniformity of rigidity in the circumferential direction and the length direction of the stent is improved, and the change in length between the diameter reduction and the expansion is further reduced.

Further, in the present invention, the knitting pattern of the metal wire rod 21 may be varied 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 the catheter is inserted or the diameter when the catheter is pushed out. 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.

As the material of the metal wire rod 21, a shape memory alloy that 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 woven fabric of a thermoplastic resin fiber formed into a cylindrical shape, or a heat formed into a cylindrical shape. 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 into a cylindrical shape, and a plain weave fabric of thermoplastic resin fibers formed into 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 is coated on the stent 20 by means such as sewing, adhesion, and welding. 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. It should be noted that the tubular cover 30 may be covered or covered on the outer circumference and / or the inner circumference of the stent 20.

As the tubular cover 30, the fibers constituting the cover, and the metal wire 21 constituting the stent 20, those coated with an antithrombotic material such as heparin, collagen, acetylsalicylic acid, or gelatin are used. 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 2 to 50 mm and a length of 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 for treating 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 stent-equipped graft 10 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, it is difficult for the metal wire rods 21 to slide with each other and the crossing angle is also difficult to change (a repulsive force is generated if the part bent in the V shape is made smaller), so that the diameter is hard to be reduced. As described above, the presence of the portion A intersecting with the cross in the periphery as described above makes it possible to maintain the ease of diameter reduction so that the work is not difficult.

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, since the line L of the portion B which is assembled and intersects is formed in a spiral shape over the entire stent 20, the stent 20 is expanded as a whole as compared with a stent including only the portion A which intersects in a cross shape. The strength is increased, and the closeness of the blood vessel B 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, since the line L of the portion B which is assembled and intersects with each other is formed in a spiral shape over the entire stent 20, the mesh elongation is restricted at that portion, so that the line in FIG. The reduced diameter state (A) and the enlarged diameter state (B) bring about an advantage that there is less change in length in the axial direction. For this reason, when pushed out from the child catheter, it is unlikely to be displaced and workability is improved.

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. In each of the following embodiments, substantially the same parts as those in the embodiment shown in FIGS. 1 to 5 are designated by the same reference numerals, and the description thereof will be omitted.

In this stent 20a, only one line L in which the assembled and intersecting portions B are continuously arranged is formed in an oblique direction (three-dimensionally spiral shape) in the developed view.
In this way, by arranging the assembled and intersecting portions B continuously, it is possible to more effectively increase the rigidity of the line L, and it is possible to expand the stent 20a without providing a plurality of lines L. Can be effectively increased, and the fluctuation of the length when the diameter is reduced and when the diameter is increased can be effectively reduced.

FIG. 7 is a development view of a knitting pattern showing still another embodiment of the stent used in the graft with a stent of the present invention.

This stent 20b has a line L in which the assembled and intersecting portions B are arranged alternately with the crossing intersecting portion A interposed therebetween. In general, three are formed in parallel with each other in a spiral shape.

In this way, the part B which is assembled and intersects is 1
By arranging every other line, the rigidity can be slightly weakened, and by forming a plurality of lines L in parallel, the rigidity of the stent 20 can be increased on average.

FIG. 8 is a development view of a knitting pattern showing still another embodiment of the stent used in the graft with a stent of the present invention.

In this stent 20c, two parts B assembled and intersecting each other are sandwiched between two parts A intersecting each other in a cross shape.
A plurality of lines L1 arranged every other line and a portion B that is assembled and intersects each other are sandwiched by three portions A that intersect in a cross shape.
It has a plurality of lines L2 arranged at every other line, and has a pattern in which these lines L1 and L2 intersect in a grid pattern.

According to this, since the parts B which are assembled and intersect with each other are arranged evenly, the rigidity of the stent 20c can be increased more uniformly. Further, since the lines L1 and L2 of the portion B which is assembled and intersects with each other intersects in a lattice pattern, it is possible to reduce the deviation in strength with respect to the stretching or bending direction.

[0052]

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 280 gf.

When the stent-equipped graft 10 covered with the tubular cover (outer circumference) 30 having an inner diameter of 22 mmφ was reduced in diameter so that the outer diameter was 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.

[0056]

As described above, according to the present invention,
It is relatively easy to reduce the diameter when it is inserted into the inner circumference of the catheter, and a sufficient expansion force is obtained when it is pushed out from the catheter. Moreover, the change in length between the diameter reduction and the diameter expansion is small, which is extremely easy to use. Stents and stented grafts can be provided.

[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.

FIG. 7 is a development view of a knitting pattern showing still another embodiment of the stent used in the stent-equipped graft of the present invention.

FIG. 8 is a development view of a knitting pattern showing still another embodiment of the stent used in the stent-equipped graft of the present invention.

[Explanation of symbols]

10 Stented graft 20 stents 21 Metal wire rod 30 tubular cover A crossing part B Part that is assembled and intersects L, L1, L2 A line with assembled and intersecting parts 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) 4C060 MM24                 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. A stent having a crossed portion. 2. The stent according to claim 1, wherein the assembled and intersecting portions are arranged in a spiral shape. 3. The stent according to claim 1, wherein the assembled and intersecting portions are arranged in a spiral shape of 0.1 or more turns. 4. One or a plurality of the cross-shaped intersecting portions are arranged between the assembled and intersecting portions, and the assembled and intersecting portions are arranged in a spiral shape while being arranged in a scattered manner. The stent according to any one of claims 1 to 3. 5. A graft with a stent comprising the stent according to any one of claims 1 to 4 and a tubular cover that covers an inner circumference and / or an outer circumference of the stent.