JP2003000723A - Stent graft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent graft which is easily adapted to a bending shape of a human body's tubular organ and which is hand to change in an axial length at the time of radial shrinking or enlarging. SOLUTION: The coupling stent graft 30 comprises a plurality of stents 32a, 32b formed by knitting metal wires 31 in a mesh-like and cylindrical state. These stents 32a, 32b are axially coupled by at least one wire 33. In this case, fixed parts 34 of the stents 32a, 32b to the wire 33 are provided at remote site ends of the stents 32a, 32b. The stents 32a, 32b and the wire 33 are covered at outer or inner peripheries with the graft 35 made of cylindrical covers. When the graft 30 is radially shrunk or enlarged, the stents 32a, 32b disposed at both ends are slid at their inside ends to the wire 33 so that the entirety of the graft 30 is not changed in length.

Description

Detailed Description of the Invention

[0001]

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

[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. Particularly in the treatment of aneurysms, a stent graft in which a woven cloth called a graft is coated on the outer circumference of the stent is used.

As a conventional stent, for example, Japanese Unexamined Patent Publication No. Hei 11
In No. 57021, a predetermined number of filaments are twisted in a sine curve shape to form a cylindrical cage-shaped braid structure, and both ends of the cylindrical cage-shaped braid structure are formed by folding or joining the filaments. Disclosed is a stent which is formed in a loop structure and in which each filament is an endless infinite loop as a whole.

Further, in Japanese Patent Laid-Open No. 2000-279529, a self-expanding type which is formed in a substantially cylindrical shape, has an outer diameter that is compressed when inserted in a living body and expands to be restored to its original shape when placed in a living body. A stent for indwelling in a 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 covered with a membrane; 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 an opening for blood circulation at a position on the end side.

[0005]

These stents have such a structure that they can be inserted into a bent shape of a tubular organ of a human body while being fit as much as possible, and that the stent is less likely to be displaced when being pushed into the tubular organ. Is required to be. In order to prevent the above-mentioned displacement from occurring easily, it is preferable that there is little change in the length of the stent between the reduced diameter state where the stent is inserted and held in the catheter and the enlarged diameter state where the stent is pushed out.

[0006] Therefore, an object of the present invention is to provide a stent graft which can be easily adapted to the bent shape of a tubular organ of a human body and whose axial length is unlikely to change between the diameter reduction and the diameter expansion. .

[0007]

In order to achieve the above object, the first aspect of the present invention is to connect a plurality of stents formed by knitting a metal wire rod into a mesh shape and a tubular shape and these stents in the axial direction. A connecting stent having at least one wire, the wire being connected to the distal ends of the stents located at both ends of the connecting stent and covering the outer circumference and / or the inner circumference of the connecting stent. The present invention provides a stent graft, which is provided with a tubular cover.

According to the above invention, since a plurality of stents formed by knitting a metal wire rod into a mesh shape and a tubular shape are axially connected by at least one wire rod,
It can be naturally bent and adapted to the bent shape of a tubular organ. Further, when the diameter of the stent is changed from the diameter-reduced shape to the diameter-expanded shape, even if the axial length of each stent changes, the axial length of the entire stent graft does not change because they are connected by the wire. Therefore, when pushed out from the catheter, it is unlikely to be displaced, and it is easy to place it accurately on the affected area. Further, since the graft composed of the tubular cover covering the outer circumference and / or the inner circumference of the connected stent is provided, for example, when the graft is placed on the inner circumference of the aneurysm of blood vessel, blood flows inside the stent and the aneurysm on the outside of the stent. Inflow can be prevented.

A second aspect of the present invention is the stent graft according to the first aspect, wherein the stents are arranged so that they do not overlap with each other in a reduced diameter state so that they can be inserted into a catheter. Is provided.

According to the above invention, since the stent graft is inserted into the catheter, when the expanded shape is changed to the contracted shape, the individual stents are in positions where they do not overlap each other even if they are extended in the axial direction. It is possible to prevent the occurrence of a trouble in which the ends of the stent come into contact with each other and become entangled with each other, which becomes an obstacle when the diameter is expanded.

A third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, a portion of the tubular cover that abuts the stent has a straight tubular shape, and the other portions have a bellows shape. The present invention provides a stent graft.

According to the above invention, since the tubular cover has a straight tubular shape in the portion where the stent is arranged, the stent can be expanded smoothly while conforming to the tubular cover. In addition, since the tubular cover has a bellows shape in a portion where the stent is not placed and only the wire is present, it is easy to fit even a bent blood vessel, and the tubular cover is kinked (flattened). It is possible to prevent the flow path from being narrowed.

A fourth aspect of the present invention provides the stent graft according to any one of the first to third aspects, wherein the wire rod has a shape bent along a circumferential direction in a portion between the plurality of stents. It is a thing.

According to the above-mentioned invention, since the wire rod is bent along the circumferential direction at the portion where the stent is not arranged and only the wire rod is formed, the portion is reinforced and kink (crushed) is obtained. ) A preventive effect is brought about.

[0015]

1 to 4 show an embodiment of a stent graft according to the present invention. FIG. 1 is a perspective view showing the stent graft without a graft in a diameter-expanded state, FIG. 2 is a perspective view without a graft in a diameter-reduced state of the stent graft, and FIG. 3 is a perspective view of the stent graft. 4 is an explanatory view showing a state in which the stent graft is arranged inside an aneurysm of a blood vessel. FIG.

This stent graft 30 is formed by knitting a predetermined number of metal wire rods 31 in a mesh shape and a tubular shape.
It has one stent 32a, 32b. These stents 32a and 32b are self-expanding stents.

In this case, as the material of the metal wire rod 31,
A shape memory alloy that imparts a shape memory effect by heat treatment or superelasticity is preferably adopted, but stainless steel, tantalum, titanium, platinum, gold, tungsten, or the like may be used depending on the application. As a shape memory alloy, Ni-Ti
A system, Cu-Al-Ni system, Cu-Zn-Al system, etc. 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 31 is not particularly limited, but in the case of, for example, a blood vessel stent, it is preferably 0.08 to 1 mm.

Various weaves can be used for weaving the metal wire 31, but at the intersections of the metal wire 31, the stent 32 is used.
It is preferable that they are not fixed except for the ends of a and 32b. By not fixing the intersection of the metal wire rod 31,
The degree of freedom of displacement between the wire rods 31 is increased, and it is possible to easily reduce the diameter when the catheter is inserted and the diameter when the catheter is pushed out. In addition, the stents 32a, 32
In the end portion of b, the portion where the end portions of the metal wire 31 overlap with each other may be fixed by, for example, solder, metal brazing, or adhesive to form the binding portion 31a.

The two stents 32a, 32b
Are connected by two wire rods 33 arranged in the axial direction. As the wire 33, the stent 32 is used.
A wire similar to the metal wire rod 31 forming a and 32b is preferably used, but a wire rod made of synthetic resin or the like can also be used. The thickness of the wire 33 is preferably 0.08 to 20 mm. Two wires 33 are attached to the distal ends of the two axially arranged stents 32a and 32b, for example, solder, brazing metal, adhesive, or polypropylene.
It is fixed with sutures such as silk and nylon.

The fixed portion 34 is formed of the stents 32a and 32b.
Is preferably provided at the farthest distal end of the stent 32a, but the effect of the present invention can be provided if the stent 32a, 32b is located on the distal end side with respect to the middle thereof. The distal end portion in the present invention is not limited to the farthest distal end as described above, but means at least a portion on the distal end side from the middle of each stent. In addition, each stent 3
It is necessary that the inner part of the middle of 2a and 32b is not fixed to the wire 33.

A graft 35 as a cylindrical cover of the present invention is coated on the outer circumference of the connected stent composed of the stents 32a and 32b and the wire material 33 connecting them.
The graft 35 is formed by molding a thermoplastic resin into a cylindrical shape processed by a molding method such as extrusion molding or blow molding,
A knitted fabric of thermoplastic resin fibers formed in a cylindrical shape, a thermoplastic resin nonwoven fabric formed in a cylindrical shape, a flexible resin sheet 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. Further, as the graft 35, one having a fold such as crimping can be used.

Among these, as the graft 35,
In particular, a knitted woven fabric of thermoplastic resin fibers formed in a cylindrical shape, and a plain weave woven fabric of thermoplastic resin fibers formed in a cylindrical shape are preferable because of their excellent strength, porosity, and productivity.

As the thermoplastic resin, polyolefin such as polyethylene, polypropylene, 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.

Particularly, 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 graft 35 is covered by a connecting stent composed of the stents 32a and 32b and a wire member 33 connecting the stents 32a and 32b by means such as sewing, adhesion and welding. The graft 35 may be coated on the inner circumference of the connecting stent.

The graft 35, the stents 32a and 32b, and the wire material 33 connecting them may be coated with an antithrombotic material such as heparin, collagen, acetylsalicylic acid and gelatin.

Further, an X-ray impermeable material may be fixed to an appropriate portion of the stent graft 30 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, brazed, welded, or welded to the stents 32a and 32b and the wire material 33 connecting them.
It can be fixed by means such as adhesion or caulking.

The stent graft 30 of the present invention thus obtained has an outer diameter of 2 to 50 mm and a length of 1 to
It is preferably about 20 cm.

Next, a method of using the stent graft 30 will be described. This stent graft 30 can be applied to any part of a human body tubular organ such as a blood vessel, a ureter, a bile duct, a bronchus, etc. In particular, it is arranged inside a blood vessel aneurysm to prevent blood from flowing into the aneurysm. It is suitable for treatment to prevent and prevent aneurysm rupture.

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 diameter of the stent graft 30 is reduced as shown in FIG. 2 and inserted into the distal end portion of the child catheter, and this child catheter is inserted into the blood vessel through the parent catheter.

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 graft 30 is pushed inside the aneurysm A'of the blood vessel A as shown in FIG. As a result, the stent graft 30
Is self-expanding, it expands in diameter by its self-expanding force, and its both ends are arranged in close contact with the inner circumference of both ends of the aneurysm A ′. At this time, the stents 32a and 32b constituting the stent graft 30 have a predetermined number of metal wire rods 3.
Since it is formed by knitting 1 into a mesh shape and a tubular shape, it naturally fits the bent shape of the blood vessel A, and adheres tightly to the inner circumference of the blood vessel A. As a result, the blood flowing through the blood vessel A does not flow into the aneurysm A ′ through the stent graft 30, so that the risk of rupture of the aneurysm A ′ can be avoided.

Further, in this stent graft 30, 2
Two stents 32a, 32b arranged axially 2
Since their distal ends are connected by the wire 33 of the book, even if the diameter is changed from the diameter-reduced state of FIG. 2 to the diameter-enlarged state of FIG. For this reason, the position of the blood vessel A is less likely to shift when pushed out from the child catheter.
It can be placed exactly in the intended place.
In addition, in the reduced diameter state of FIG.
It is preferable to define the interval between the two 2a and 32b so that they do not overlap each other.

5 and 6 show other respective embodiments of the stent graft according to the present invention. In the following description, substantially the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

That is, the stent graft 3 shown in FIG.
In 0a, the single wire 33 that connects the two stents 32a and 32b is configured. Further, in the stent graft 30b shown in FIG. 6, the two stents 32a, 32
The wire 33 that connects b is composed of three wires. Thus, at least one wire 33 is sufficient, and two wires 33,
The number may be three or more.

As in the above embodiment, each wire 33
Is fixed to the distal ends of the two stents 32a and 32b by a fixing portion 34, and the stent graft 30a
When the diameter of the stent is reduced or expanded, the inner ends of the respective stents 32a and 32b slide with respect to the wire rod 33 as shown by the arrows in the figure, and the length of the stent graft 30a as a whole does not change. There is.

FIG. 7 shows still another embodiment of the stent graft according to the present invention. In this stent graft 30c, another stent 32c is arranged between two stents 32a and 32b. The two wires 33 have stents 32a and 32b arranged at both ends.
It is fixed to the distal end of the by a fixing portion 34. Further, it is also fixed to one end of the stent 32c arranged in the middle by the fixing portion 34. In this stent graft 30c, when the diameter is reduced or expanded, the ends of the respective stents 32a, 32b, 32c, which are not fixed, slide as shown by the arrows in the figure, and the overall length of the stent graft 30a. Is not changing.

FIG. 8 shows still another embodiment of the stent graft according to the present invention. This stent graft 30d is basically the same as the embodiment shown in FIG. 7, and includes three stents 32a, 32b, 32c.
It has a structure in which it is connected by a wire 33 of a book. However, this embodiment is different in that the wire 33 is fixed to the middle of the stent 32c arranged in the middle by a fixing portion 34. In this stent graft 30c, when the diameter is reduced or expanded, the stent 32c arranged in the middle
The both ends slide as shown by the arrows in the figure. In this manner, the wire rod 33 has the stent 32 arranged at both ends.
It is necessary to be fixed to the distal ends of a and 32b, but it may be fixed to any position with respect to the stent 32c arranged in the middle part. However, the stents 32a, 3
It is preferable that each fixing point is one so as not to impair expansion and contraction of 2b and 32c.

9A and 9B show still another embodiment of the stent graft according to the present invention. FIG. 9A is a perspective view and FIG. 9B is a perspective view with the graft omitted.

This stent graft 30e is basically the same as the embodiment shown in FIGS. 1 to 4, except that the graft 35 as a tubular cover has a straight tubular portion 35a and a bellows shape. The difference is that it is configured with the formed portion 35b. In this case, the straight tubular portion 35a is arranged at a portion that abuts the stents 32a and 32b, and the bellows-shaped portion 35b is
It is arranged in a portion formed only of the wire rod 33 between the stents 32a and 32b.

According to this stent graft 30e, in the straight tubular portion 35a of the graft 35, the stents 32a and 32b can be smoothly expanded in conformity with the graft 35, and at the bellows-shaped portion 35b of the graft 35. Can easily fit into a bent portion such as a blood vessel, and can prevent the graft 35 from being kinked (crushed) at the bent portion to narrow the flow path.

FIG. 10 shows still another embodiment of the stent graft according to the present invention. This stent graft 30f is basically the same as the embodiment shown in FIGS. 1 to 4, but the stents 32a, 32b of the wire 33 are the same.
Between the two, namely the stents 32a, 32
The difference is that the wire 33 is bent in a U shape along the circumferential direction in a portion where only the wire 33 is provided without b.

According to this stent graft 30f, since the U-shaped bent portion 33a is provided in the portion where only the wire rod 33 is provided without the stents 32a and 32b, even if the stent graft 30f is bent at that portion. It is possible to prevent the flow path from being kinked (crushed) and being narrowed.

[0043]

As described above, according to the present invention,
Since a plurality of stents formed by knitting a metal wire rod into a mesh shape and a tubular shape are connected in the axial direction by at least one wire rod, it can be naturally bent and adapted to the bent shape of the tubular organ. You can Further, when the diameter of the stent is changed from the diameter-reduced shape to the diameter-expanded shape, even if the axial length of each stent changes, the axial length of the entire stent graft does not change because they are connected by the wire. Therefore, when pushed out from the catheter, it is unlikely to be displaced, and it is easy to place it accurately on the affected area.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a stent graft according to the present invention with the graft omitted in a state where the diameter is expanded.

FIG. 2 is a perspective view showing the stent graft with the graft omitted in a reduced diameter state.

FIG. 3 is a perspective view of the stent graft.

FIG. 4 is an explanatory view showing a state in which the stent graft is arranged inside a blood vessel aneurysm.

FIG. 5 is a perspective view showing another embodiment of the stent graft according to the present invention, with the graft omitted in the expanded state.

FIG. 6 is a perspective view showing still another embodiment of the stent graft according to the present invention, with the graft omitted in the expanded state.

FIG. 7 is a perspective view showing still another embodiment of the stent graft according to the present invention, with the graft omitted in the expanded state.

FIG. 8 is a perspective view showing still another embodiment of the stent graft according to the present invention, with the graft omitted in the expanded state.

9A and 9B show still another embodiment of the stent graft according to the present invention, FIG. 9A is a perspective view, and FIG.

FIG. 10 is a perspective view showing still another embodiment of the stent graft according to the present invention, with the graft omitted in the expanded state.

[Explanation of symbols]

30, 30a, 30b, 30c, 30d, 30e, 30
f Stent graft 31 Metal wire rods 32a, 32b, 32c Stent 33 Wire rod 34 Fixed part 35 Graft A Blood vessel A'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 AA45 AA50 AA53 BB05                       BB07 BB10 BB14 CC08 CC21                       CC22 CC26 DD08 EE03 GG04                       GG05 GG07 GG22 GG24 GG32                       GG36 HH08

Claims (4)

[Claims] 1. A connecting stent having a plurality of stents formed by knitting a metal wire rod in a mesh shape and a tubular shape, and at least one wire rod connecting these stents in an axial direction, the wire rod comprising: A stent graft provided with tubular covers connected to the distal ends of the stents arranged at both ends of the connected stent and covering the outer circumference and / or the inner circumference of the connected stent. 2. The stent graft according to claim 1, wherein the stents are arranged in a reduced diameter so that they can be inserted into a catheter and do not overlap each other. 3. The stent graft according to claim 1, wherein the tubular cover has a straight tubular shape at a portion contacting with the stent, and has a bellows shape at the other portion. 4. The stent graft according to claim 1, wherein the wire has a shape bent along a circumferential direction in a portion between the plurality of stents.